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Wyszukujesz frazę "sampling" wg kryterium: Temat


Tytuł:
Prediction of a Function of Misclassified Binary Data
Autorzy:
Al-Kandari, Noriah M.
Powiązania:
https://bibliotekanauki.pl/articles/973541.pdf
Data publikacji:
2016
Wydawca:
Główny Urząd Statystyczny
Tematy:
binary classification
double sampling
finite population sampling
misclassification
linkage error
sampling design
Opis:
We consider the problem of predicting a function of misclassified binary variables. We make an interesting observation that the naive predictor, which ignores the misclassification errors, is unbiased even if the total misclassification error is high as long as the probabilities of false positives and false negatives are identical. Other than this case, the bias of the naive predictor depends on the misclassification distribution and the magnitude of the bias can be high in certain cases. We correct the bias of the naive predictor using a double sampling idea where both inaccurate and accurate measurements are taken on the binary variable for all the units of a sample drawn from the original data using a probability sampling scheme. Using this additional information and design-based sample survey theory, we derive a biascorrected predictor. We examine the cases where the new bias-corrected predictors can also improve over the naive predictor in terms of mean square error (MSE).
Źródło:
Statistics in Transition new series; 2016, 17, 3; 429-448
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testing of adaptive nonuniform sampling switch algorithm with real-time simulation-in-the-loop
Autorzy:
Janczak, J.
Kondratiuk, M.
Pawluszewicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/206431.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
nonuniform sampling
sampled-data control
adaptive nonuniform sampling
Opis:
The study is motivated by the considerations concerning implementation of nonuniform sampling regarding the reallife objects. It is shown that nonuniform adaptive sampling switch algorithm can ensure a reduction in the number of taken samples and does not exert negative influence on the quality of the system control. Experiment was performed with 24VDC permanent magnet motor with encoder as a plant. Signals from the encoder were used for rotational speed calculations. The results of experiment are included.
Źródło:
Control and Cybernetics; 2016, 45, 3; 317-328
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Choice of Methods of Checking on Total Quality Control Costs
Wpływ wyboru metody sprawdzania na całkowite koszty kontroli jakości
Autorzy:
Chmielińska, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/905656.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
statistical quality control
acceptance sampling
acceptance sampling costs
Opis:
Acceptance sampling is commonly used in factories, because it decreases the probability of giving defective batch to the customer. From two distinguished ways of acceptance sampling, more frequently in practice is used an attribute sampling method. The purpose of this article is to emphasize the benefits of using acceptance sampling by variables.
Kontrola odbiorcza jest powszechnie stosowana w przedsiębiorstwach produkcyjnych, gdyż zmniejsza ona prawdopodobieństwo przekazania klientowi wadliwej partii produktów. Z wyróżnionych dwóch sposobów kontroli odbiorczej częściej wykorzystywana w praktyce jest kontrola według oceny alternatywnej. Celem niniejszego artykułu jest podkreślenie korzyści wynikających ze stosowania liczbowych planów kontroli odbiorczej.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2013, 285
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-stage cluster sampling with unequal probability sampling in the first stage and ranked set sampling in the second stage
Autorzy:
Ugwu, Michael C.
Madukaife, Mbanefo S.
Powiązania:
https://bibliotekanauki.pl/articles/2108165.pdf
Data publikacji:
2022-09-14
Wydawca:
Główny Urząd Statystyczny
Tematy:
cluster sampling
population mean estimator
probability proportional to size sampling
ranked set sampling
relative efficiency
Opis:
In this research work we introduce a new sampling design, namely a two-stage cluster sampling, where probability proportional to size with replacement is used in the first stage unit and ranked set sampling in the second in order to address the issue of marked variability in the sizes of population units concerned with first stage sampling. We obtained an unbiased estimator of the population mean and total, as well as the variance of the mean estimator. We calculated the relative efficiency of the new sampling design to the two-stage cluster sampling with simple random sampling in the first stage and ranked set sampling in the second stage. The results demonstrated that the new sampling design is more efficient than the competing design when a significant variation is observed in the first stage units.
Źródło:
Statistics in Transition new series; 2022, 23, 3; 199-214
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variance estimation in stratified adaptive cluster sampling
Autorzy:
Yasmeen, Uzma
Noor-ul-Amin, Muhammad
Hanif, Muhammad
Powiązania:
https://bibliotekanauki.pl/articles/2034098.pdf
Data publikacji:
2022
Wydawca:
Główny Urząd Statystyczny
Tematy:
variance estimator
stratified sampling
stratified adaptive cluster sampling (SACS)
Opis:
In many sampling surveys, the use of auxiliary information at either the design or estimation stage, or at both these stages is usual practice. Auxiliary information is commonly used to obtain improved designs and to achieve a high level of precision in the estimation of population density. Adaptive cluster sampling (ACS) was proposed to observe rare units with the purpose of obtaining highly precise estimations of rare and specially clustered populations in terms of least variances of the estimators. This sampling design proved to be more precise than its more conventional counterparts, including simple random sampling (SRS), stratified sampling, etc. In this paper, a generalised estimator is anticipated for a finite population variance with the use of information of an auxiliary variable under stratified adaptive cluster sampling (SACS). The bias and mean square error expressions of the recommended estimators are derived up to the first degree of approximation. A simulation study showed that the proposed estimators have the least estimated mean square error under the SACS technique in comparison to variance estimators in stratified sampling.
Źródło:
Statistics in Transition new series; 2022, 23, 1; 173-184
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial sampling methods modified by model use
Autorzy:
Bąk, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1054565.pdf
Data publikacji:
2021-06-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
spatial sampling
drawn-by-drawn sampling
kriging
employees distribution
Opis:
Recent years have seen an intensive development in the field of spatial sampling methods, which generally focus on a balanced distribution of the sample in space. Adaptive sampling methods constitute another dynamic direction in the sampling theory. The issue raised in this article involves the combination of these directions. Five of the commonly known spatial sampling methods have been analysed. The experiment was designed to include statistical model in the sampling procedure. As in the case of adaptive methods, it serves to modify drawing probabilities during sampling. The necessary theory of this sampling modification has been developed and presented. An experiment using artificial data was conducted in order to analyse the efficiency of the model modification in comparison with the primary methods.
Źródło:
Statistics in Transition new series; 2021, 22, 2; 143-154
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sub-phase power electronics inverters
Autorzy:
Gwóźdź, M.
Powiązania:
https://bibliotekanauki.pl/articles/97361.pdf
Data publikacji:
2011
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
inverter
Generalized Sampling Expansion
Whittaker-Kotelnikov-Shannon sampling theorem
WKS
Opis:
Dynamic changes of parameters of energy sources and receivers are reasons that decrease exactitude of output signals towards reference signals. To improve these parameters more advanced solutions of power electronics systems are necessary. Ones of possible solutions are a sub-phase inverters. The output quantity regulator there is based on Generalized Sampling Expansion, being crucial extension of Whittaker-Kotelnikov-Shannon sampling theorem. Wide-band power electronics current source with regulator based on that extension is analyzed further.
Źródło:
Computer Applications in Electrical Engineering; 2011, 9; 190-199
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonuniform Spatial Sampling in a Ground-Based Noise SAR
Autorzy:
Maślikowski, Ł.
Misiurewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/226510.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nonuniform sampling
noise radar
synthetic aperture
radar (SAR)
compressive sampling
Opis:
The paper presents an idea of nonuniform spatial sampling applied to a noise synthetic aperture radar. In certain cases it is desirable to limit the number of spatial (alongtrack) domain samples acquired in a SAR radar because of external constraints on sampling frequency or on the overall number of samples – e.g. in order to economy on time or power consumed. Lowering number of samples taken may, however, lead to spatial aliasing and incorrect reconstruction of the image. Nonuniform sampling allows to reduce the aliasing effect and reconstruct the image better. This technique can be applied with standard reconstruction methods, but it works best together with Compressive Sensing reconstruction algorithms. The idea will be verified with an experimental noise SAR built at ISE PW.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 1; 71-75
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new ratio estimator: an alternative to regression estimator in survey sampling using auxiliary information
Autorzy:
Subzar, Mir
Maqbool, S.
Raja, T. A.
Sharma, Prayas
Powiązania:
https://bibliotekanauki.pl/articles/1186907.pdf
Data publikacji:
2019-12-10
Wydawca:
Główny Urząd Statystyczny
Tematy:
simple random sampling
Opis:
The most dominant problem in the survey sampling is to obtain the better ratio estimators for the estimation of population mean or population variance. Estimation theory is enhanced by using the auxiliary information in order to improve on designs, precision and efficiency of estimators. A modified class of ratio estimator is suggested in this paper to estimate the population mean. Expressions for the bias and the mean square error of the proposed estimators are obtained. Both analytical and numerical comparison has shown the suggested estimator to be more efficient than some existing ones. The bias of the suggested estimator is also found to be negligible for the population under consideration, indicating that the estimator is as good the regression estimator and better than the other estimators under consideration.
Źródło:
Statistics in Transition new series; 2019, 20, 4; 181-189
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the strategy combining monetary unit sampling and a Horvitz-Thompson estimator of error amount in auditing – results of a simulation study
Autorzy:
Janusz, Bartłomiej
Powiązania:
https://bibliotekanauki.pl/articles/1194460.pdf
Data publikacji:
2019-07-02
Wydawca:
Główny Urząd Statystyczny
Tematy:
audit sampling
Monetary Unit Sampling
Horvitz-Thompson estimator
error distribution
Opis:
Auditors need information on the performance of different statistical methods when applied to audit populations. The aim of the study was to examine the reliability and efficiency of a strategy combining systematic Monetary Unit Sampling and confidence intervals for the total error based on the Horvitz-Thompson estimator with normality assumption. This strategy is a possible alternative for testing audit populations with high error rates. Using real and simulated data sets, for the majority of populations, the interval coverage rate was lower than the assumed confidence level. In most cases confidence intervals were too wide to be of practical use to auditors. Confidence intervals tended to become wider as the observed error rate increased. Tests disclosed the distribution of the HorvitzThompson estimator was not normal. A detailed analysis of the distributions of the error amount in the examined real audit populations is also given.
Źródło:
Statistics in Transition new series; 2019, 20, 2; 85-106
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Domain Means on The Basis of Strategy Dependent on Depth Function of Auxiliary Variables’ Distribution
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465849.pdf
Data publikacji:
2011
Wydawca:
Główny Urząd Statystyczny
Tematy:
sampling design
order statistic
auxiliary variable
sampling scheme
Horvitz-Thompson estimator
small area estimation
area sampling
depth function
Opis:
The paper deals with the problem of estimation of a domain means in a finite and fixed population. We assume that observations of a multidimensional auxiliary variable are known in the population. The proposed estimation strategy consists of the well known Horvitz-Thompson estimator and the non-simple sampling design dependent on a synthetic auxiliary variable whose observations are equal to the values of a depth function of the auxiliary variable distribution. The well known spherical and Mahalanobis depth functions are considered. A sampling design is proportionate to the maximal order statistic determined on the basis of the synthetic auxiliary variable observations in a simple sample drawn without replacement. A computer simulation analysis leads to the conclusion that the proposed estimation strategy is more accurate for domain means than the well known simple sample means.
Źródło:
Statistics in Transition new series; 2011, 12, 1; 127-138
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Order Statistics of Auxiliary Variable to Estimation the Population Mean
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465810.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
Order statistic
sample quantile
auxiliary variable
sampling scheme
sampling design
concomitant
Opis:
Estimation of the population average in a finite population by means of sampling strategies dependent on an auxiliary variable highly correlated with a variable under study is considered. The sample is drawn with replacement on the basis of the probability distribution of an order statistic of the auxiliary variable. Observations of the variable under study are the values of the concomitant of the order statistic. The mean of the concomitant values is the estimator of a population mean of the variable under study. The expected value and the variance of the estimator are derived. The limit distributions of the considered estimators were considered. Finally, on the basis of simulation analysis, the accuracy of the estimator is considered.
Źródło:
Statistics in Transition new series; 2012, 13, 2; 279-286
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Unexpected Result on Modelling the Behavior of A/D Converters and the Signals They Produce
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2203003.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modelling
signal
sampling operation
Opis:
In this paper, we show that the signal sampling operation considered as a non-ideal one, which incorporates finite time switching and operation of signal blurring, does not lead, as the researchers would expect, to Dirac impulses for the case of their ideal behavior.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 1; 185--191
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Order of approximation for nonlinear sampling Kantorovich operators in Orlicz spaces
Autorzy:
Costarelli, Danilo
Vinti, Gianluca
Powiązania:
https://bibliotekanauki.pl/articles/745018.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Nonlinear sampling Kantorovich operators, Orlicz spaces, order of approximation, Lipschitz classes, irregular sampling
Opis:
In this paper, we study the rate of approximation for the nonlinear sampling Kantorovich operators. We consider the case of uniformly continuous and bounded functions belonging to Lipschitz classes of the Zygmund-type, as well as the case of functions in Orlicz spaces. We estimate the aliasing errors with respect to the uniform norm and to the modular functional of the Orlicz spaces, respectively. The general setting of Orlicz spaces allows to deduce directly the results concerning the rate of convergence in \(L^p\)-spaces, \(1 \miu p\) < \(\infty\), very useful in the applications to Signal Processing. Others examples of Orlicz spaces as interpolation spaces and exponential spaces are discussed and the particular cases of the nonlinear sampling Kantorovich series constructed using Fej\'er and B-spline kernels are also considered.
Źródło:
Commentationes Mathematicae; 2013, 53, 2
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonresponse Bias in The Survey of Youth Understanding of Science and Technology in Bogotá
Autorzy:
Castellanos, Edgar Mauricio Bueno
Powiązania:
https://bibliotekanauki.pl/articles/466054.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
Sampling design
nonresponse bias
calibration
Opis:
The Colombian Observatory of Science and Technology -OCyT- developed, in 2009, a survey about understanding of Science and Technology in students of high school in Bogotá, Colombia. The sampling design was stratified according to the nature of school (public or private). Two sources of unit nonresponse were detected. The first one corresponds to schools that did not allowed to collect information. The second source corresponds to students who did not assist during the days when survey was applied. Estimates were obtained through two different approaches. Results obtained in both cases do not show visible differences when estimating ratios; even though, some great differences were observed when estimating totals. Results obtained using the second approach are believed to be more reliable because of the methodology used to handle item nonresponse.
Źródło:
Statistics in Transition new series; 2012, 13, 1; 79-94
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zwiększenie efektywności inwentaryzacji lasu metodą losowania warstwowego
Improving effectiveness of forest inventory by stratified sampling
Autorzy:
Banaś, J.
Drozd, M.
Zięba, S.
Bujoczek, L.
Powiązania:
https://bibliotekanauki.pl/articles/986979.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
inwentaryzacja lasu
losowanie warstwowe
poprawa efektywnosci
sampling design
inventory precision
stratified sampling
Opis:
The purpose of the stratification is to group stands basing on the homogeneity of the measured feature. During periodic forest inventory in Poland, strata are created on the basis of age and the main species in stand within the boundary of forest district. In this work an improvement of distinguishing the strata during the forest inventory is presented. Three variants are considered: (1) distinguishing homogeneous strata in boundary of the whole forest district, not separately in forest subdistricts, (2) splitting species−aged strata into homogeneous substrata with respect to site quality, and (3) dividing strata of stands in the regeneration class with respect to stand density. Study was conducted in four mountain forest districts located in the Kłodzko Basin (SW Poland). Total area of these stands amounted to 43,052 ha, where 6,648 sample plots were established during the periodic inventory. ANOVA was used to test significance of the differences in tree volume and to assess variability reducing in distinguished substrata. Results indicated that in stands with age up to 70 years mean volume of trees on the sample plot does not differ significantly between sites, but in older stands difference was significant. Dividing age−species strata of stands older than 70 years into substrata according to site conditions influenced reduction of volume variability from 10 to 57% in newly created substrata. Dividing strata consisted of stands in regeneration class according to stand density index allowed to decrease the volume variability from 9 to 20%. Mean volume of trees in stands on similar sites does no differ significantly between subdistricts in the same forest district. Strata distinguished within the whole forest district are bigger and represented by more sample plots than on the subdistrict level, which significantly reduced standard error of volume and improved effectiveness of stratification in forest inventory.
Źródło:
Sylwan; 2017, 161, 10; 804-811
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the performance of modified EWMA charts using resampling schemes
Autorzy:
Khan, N.
Yasmin, T.
Aslam, M.
Jun, C. -H.
Powiązania:
https://bibliotekanauki.pl/articles/406444.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
repetitive group sampling
multiple dependent state sampling
EWMA statistic
average run length
simulation
Opis:
Two popular sampling schemes have been used to design control charts by means of a modified exponentially weighted moving average (EWMA) statistic. The structures of the proposed charts, using repetitive group sampling and multiple dependent state sampling, have been presented. The values of average run length have been determined by some specified control chart parameters. The performance of the proposed chart was illustrated via a simulation study. The efficiency of the proposed chart has been compared with the existing one. A practical example based on real data was also given to explain the application of the proposed chart in industry.
Źródło:
Operations Research and Decisions; 2018, 28, 3; 29-43
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Effective Estimation Procedures Under Non- Esponse in Two-Phase Successive Sampling
Autorzy:
Singh, G. N.
Khetan, M.
Maurya, S.
Powiązania:
https://bibliotekanauki.pl/articles/465962.pdf
Data publikacji:
2016
Wydawca:
Główny Urząd Statystyczny
Tematy:
non-response, successive sampling two-phase sampling
mean square error
optimum replacement strategy
Opis:
This work is designed to assess the effect of non-response in estimation of the current population mean in two-phase successive sampling on two occasions. Sub-sampling technique of non-respondents has been used and exponential methods of estimation under two-phase successive sampling arrangement have been proposed. Properties of the proposed estimation procedures have been examined. Empirical studies are carried out to justify the suggested estimation procedures and suitable recommendations have been made to the survey practitioners.
Źródło:
Statistics in Transition new series; 2016, 17, 2; 163-182
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Conditional Simple Random Sample
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465622.pdf
Data publikacji:
2014
Wydawca:
Główny Urząd Statystyczny
Tematy:
simple random sample
conditional sampling design
sampling scheme
inclusion probabilities
auxiliary variable
order statistics
Opis:
Estimation of the population average in a finite and fixed population on the basis of the conditional simple random sampling design dependent on order statistics of the auxiliary variable is studied. The sampling scheme implementing the sampling design is proposed. The inclusion probabilities are derived. The well known Horvitz-Thompson statistic under the conditional simple random sampling designs is considered as the estimator of population mean. Moreover, it was shown that the Horvitz-Thompson estimator under some particular cases of the conditional simple random sampling design is more accurate than the ordinary mean from the simple random sample.
Źródło:
Statistics in Transition new series; 2014, 15, 4; 525-534
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods for combining probability and nonprobability samples under unknown overlaps
Autorzy:
Savitsky, Terrance D.
Williams, Matthew R.
Gershunskaya, Julie
Beresovsky, Vladislav
Powiązania:
https://bibliotekanauki.pl/articles/31342142.pdf
Data publikacji:
2023-12-07
Wydawca:
Główny Urząd Statystyczny
Tematy:
Survey sampling
Nonprobability sampling
Data combining
Inclusion probabilities
Exact sample likelihood
Bayesian hierarchical modeling
Opis:
Nonprobability (convenience) samples are increasingly sought to reduce the estimation variance for one or more population variables of interest that are estimated using a randomized survey (reference) sample by increasing the effective sample size. Estimation of a population quantity derived from a convenience sample will typically result in bias since the distribution of variables of interest in the convenience sample is different from the population distribution. A recent set of approaches estimates inclusion probabilities for convenience sample units by specifying reference sample-weighted pseudo likelihoods. This paper introduces a novel approach that derives the propensity score for the observed sample as a function of inclusion probabilities for the reference and convenience samples as our main result. Our approach allows specification of a likelihood directly for the observed sample as opposed to the approximate or pseudo likelihood. We construct a Bayesian hierarchical formulation that simultaneously estimates sample propensity scores and the convenience sample inclusion probabilities. We use a Monte Carlo simulation study to compare our likelihood based results with the pseudo likelihood based approaches considered in the literature.
Źródło:
Statistics in Transition new series; 2023, 24, 5; 1-34
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new OSS design based on parameter sensitivity to changes in measurements
Autorzy:
Kalicka, R.
Bochen, D.
Powiązania:
https://bibliotekanauki.pl/articles/969953.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal sampling schedule
sensitivity criterion
Opis:
As a result of the severe practical and ethical constraints imposed on medical measurements, the parameter estimation procedure designed for diagnosis and therapy is often a difficult problem. When blood sampling provides the data, the number of samples and the observation interval should be minimized. Designing an experiment for parameter estimation requires a step known as quantitative experiment design, usually preceded by a step called qualitative experiment design. The latter answers if a model is identifiable under particular experimental conditions. The former is suitable for the purpose of obtaining the maximum information from the data to be collected. An experiment design is based on the optimization of a suitable criterion formulated with respect to the analyzed variables of the experiment (input shape, sampling schedule). This paper considers sampling schedule design. New criteria for new optimal sampling schedules (OSS) have been formulated on the basis of sensitivity function. These are referred to as S-OSS and RS-OSS designs. The results of optimization for both criteria are compared with the result obtained with a reputable established D-optimal design based on the Fisher information matrix. By showing the results of S-OSS and RS-OSS design we can present the reliability and efficiency of the new criteria in comparison to D-OSS design. Illustrative examples are presented.
Źródło:
Control and Cybernetics; 2006, 35, 2; 385-406
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ADC Emulation on FPGA
Autorzy:
Tabassum, Huma
Prathik BV, Krishna
Hiremath, Sujatha S.
Powiązania:
https://bibliotekanauki.pl/articles/27311968.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ADC
resolution
FPGA
sampling
conversion
Opis:
Analog-to-Digital Converters (ADCs) are devices that transform analog signals into digital signals and are used in various applications such as audio recording, data acquisition, and measurement systems [1]. Prior to the development of actual chip, there is a need for prototyping, testing and verifying the performance of ADCs in different scenarios. Analog macros cannot be tested on an FPGA. In order to ensure the macros function properly, the emulation of the ADC is done first. This is a digital module and can be designed in System Verilog. This paper demonstrates the design of the module on FPGA for Analog to Digital Converter (ADC) emulation. The emulation is done specific to the ADC macro which has programmable resolutions of 12/10/8/6 bit.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 3; 425--430
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended Definitions of Spectrum of a Sampled Signal
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1844508.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spectrum of sample signal
ideal versus non-ideal sampling
modelling of signal sampling process
Opis:
It is shown that a number of equivalent choices for the calculation of the spectrum of a sampled signal are possible. Two such choices are presented in this paper. It is illustrated that the proposed calculations are more physically relevant than the definition currently in use.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 3; 395-401
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameter estimation of exponentiated exponential distribution under selective ranked set sampling
Autorzy:
Hassan, Amal S.
Elshaarawy, Rasha S.
Nagy, Heba F.
Powiązania:
https://bibliotekanauki.pl/articles/2156898.pdf
Data publikacji:
2022-12-15
Wydawca:
Główny Urząd Statystyczny
Tematy:
exponentiated exponential distribution
partial ranked set sampling
neoteric ranked set sampling
maximum likelihood method
Opis:
Partial ranked set sampling (PRSS) is a cost-effective sampling method. It is a combination of simple random sample (SRS) and ranked set sampling (RSS) designs. The PRSS method allows flexibility for the experimenter in selecting the sample when it is either difficult to rank the units within each set with full confidence or when experimental units are not available. In this article, we introduce and define the likelihood function of any probability distribution under the PRSS scheme. The performance of the maximum likelihood estimators is examined when the available data are assumed to have an exponentiated exponential (EE) distribution via some selective RSS schemes as well as SRS. The suggested ranked schemes include the PRSS, RSS, neoteric RSS (NRSS), and extreme RSS (ERSS). An intensive simulation study was conducted to compare and explore the behaviour of the proposed estimators. The study demonstrated that the maximum likelihood estimators via PRSS, NRSS, ERSS, and RSS schemes are more efficient than the corresponding estimators under SRS. A real data set is presented for illustrative purposes.
Źródło:
Statistics in Transition new series; 2022, 23, 4; 37-58
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On modelling and description of the output signal of a sampling device
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2202544.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal sampling
modelling
ideal or non-ideal sampling
averaging operator
Dirac and Kronecker deltas
Opis:
The problem of an inconsistent description of an “interface” between the A/D converter and the digital signal processor that implements, for example, a digital filtering (described by a difference equation) – when a sequence of some hypothetical weighted Dirac deltas occurs at its input, instead of a sequence of numbers – is addressed in this paper. Digital signal processors work on numbers, and there is no “interface” element that converts Dirac deltas into numbers. The output of the A/D converter is directly connected to the input of the signal processor. Hence, a clear conclusion must follow that sampling devices do not generate Dirac deltas. Not the other way around. Furthermore, this fact has far-reaching implications in the spectral analysis of discrete signals, as discussed in other works referred to in this paper.
Źródło:
Archives of Electrical Engineering; 2023, 72, 1; 147--155
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability and efficiency of the D, E, S, A-optimal sampling schedule design
Autorzy:
Kalicka, R.
Bochen, D.
Powiązania:
https://bibliotekanauki.pl/articles/1954507.pdf
Data publikacji:
1999
Wydawca:
Politechnika Gdańska
Tematy:
modelling
optimal sampling schedules
various criteria
Opis:
Due to the sharp practical and ethical constraints imposed on medical measurements, the parameter estimation procedure that is designed for diagnosis and therapy is often a difficult problem. When blood sampling provides the data, the number of samples and the measurement interval should be minimised. We have implemented D (determinant), E (eigenvalue), S (sensitivity) and A (trace) optimal sampling schedules (OSSs). These OSSs have minimal size, which means that the number of samples is equal to the number of model parameters that are being estimated. Setting up the results of the D, E, S and A approaches allows us to compare their efficiency and usefulness. Illustrative examples are presented.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1999, 3, 4; 453-464
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the application of compressive sampling techniques to high throughput data in computational genomics
Autorzy:
Hernández-Lemus, H.
Powiązania:
https://bibliotekanauki.pl/articles/375726.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compressive sampling
compressed sensing
computational genomics
Opis:
With the advent of high throughput experiments in genomics and proteomics, the researcher in computational data analysis is faced with new challenges, both with regards to the computational capacities and also in the probabilistic/statistical methodology fields; in order to handle such massive amounts of data in a systematic coherent way. In this paper we describe the basic aspects of the mathematical theory and the computational implications of a recently developed technique called Compressive Sampling, as well as some possible applications within the scope of Computational Genomics, and Computational Biology in general. The central idea behind this work is that most of the information sampled from the experiments turns out to be discarded (for being non-useful) in the final stages of biological analysis, hence it would be better if we could find an algorithm to remove selectively such information in order to get rid of the computational burden associated with processing and analyzing such huge amounts of data. Here we show that a possible algorithm for doing so it is precisely Compressive Sampling. As a working example, we will consider the data-analysis of whole-genome microarray gene expression for 1191 individuals within a breast cancer project.
Źródło:
Theoretical and Applied Informatics; 2011, 23, 3-4; 177-192
1896-5334
Pojawia się w:
Theoretical and Applied Informatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surveying Child Labour Through Households: Sampling Issues and Strategies
Autorzy:
Verma, Vijay
Gagliardi, Francesca
Powiązania:
https://bibliotekanauki.pl/articles/465721.pdf
Data publikacji:
2010
Wydawca:
Główny Urząd Statystyczny
Tematy:
child labour
household surveys
sampling
ILO
Opis:
This paper addresses sampling issues arising in the context of household-based child labour surveys. It presents some of the sampling strategies elaborated in the ILO book Sampling for Household-based Surveys of Child Labour (Verma, 2008). A typology of surveys of child labour is identified, and the fundamental distinction between two types with very different objectives - termed 'child labour surveys' and 'labouring children surveys', respectively - is clarified and emphasised. Following a broad survey of national practices in conducting surveys of child labour, linkages between different types of surveys and some specific sampling techniques are explained.
Źródło:
Statistics in Transition new series; 2010, 11, 3; 6-37
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical and mechanical properties of the black turnip root flesh
Autorzy:
Starek, A.
Kusińska, E.
Guz, T.
Powiązania:
https://bibliotekanauki.pl/articles/410690.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
black turnip
physical properties
sampling site
Opis:
The paper presents the results of measurement of the basic physical properties of black turnip and the results of studies on the impact of sampling site on the textural properties of its pulp. Selected texture indices, i.e. hardness, elasticity, cohesiveness and chewiness, were determined using the TPA double compression test. The tests were carried out on samples taken from well-defined root layers (upper layer, middle layer, lower layer) and zones (A, B, C) of black turnip, because of its structural heterogeneity. The samples were compressed at the longitudinal and transverse direction of the fibers relative to the compressing device movement. The results obtained were statistically analyzed using the Statistica 10.0 program. The research has shown that the site of sampling and the direction of fiber positioning have a significant impact on the value of all the black turnip texture parameters.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2018, 7, 1; 127-136
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the Categorisation Method Using Long-term Measurements
Autorzy:
Rey Gozalo, G.
Barrigón Morillas, J. M.
Gómez Escobar, V.
Vílchez-Gómez, R.
Méndez Sierra, J. A.
Carmona del Río, F. J.
Prieto Gajardo, C.
Powiązania:
https://bibliotekanauki.pl/articles/177690.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
noise pollution
sampling methods
street categorisation
Opis:
Previous studies concerning the categorisation method have been based on short daytime measure- ments. These studies demonstrated urban-noise stratification in the daytime. Nevertheless, legislation and standards refer to noise estimation throughout the day. This paper presents the first attempt to apply the categorisation method to indicators obtained through long-term measurements. The study was conducted in Plasencia, Extremadura (Spain) which has approximately 41,500 inhabitants. First, we conducted a stratification of the roads using the categorisation method. Second, long-term measurements (approxi- mately one week) were conducted at different sampling locations across different categories of streets. The results were analysed by category. Moreover, the profile of the noise-level variation was analysed during the day. The results revealed a stratification of sound levels measured across the different categories. Furthermore, we found health risks due to the noise levels in this town. Short-term measurements were also conducted to complete the categorisation method suitability analysis.
Źródło:
Archives of Acoustics; 2013, 38, 3; 397-405
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimized Driver Placement for Array-Driven Flat-Panel Loudspeakers
Autorzy:
Anderson, D. A.
Heilemann, M. C.
Bocko, M. F.
Powiązania:
https://bibliotekanauki.pl/articles/177774.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
loudspeaker
array
crossover network
spatial sampling
Opis:
The recently demonstrated ‘modal crossover network’ method for flat panel loudspeaker tuning employs an array of force drivers to selectively excite one or more panel bending modes from a spectrum of panel bending modes. A regularly spaced grid of drivers is a logical configuration for a two-dimensional driver array, and although this can be effective for exciting multiple panel modes it will not necessarily exhibit strong coupling to all of the modes within a given band of frequencies. In this paper a method is described to find optimal force driver array layouts to enable control of all the panel bending modes within a given frequency band. The optimization is carried out both for dynamic force actuators, treated as point forces, and for piezoelectric patch actuators. The optimized array layouts achieve similar maximum mode coupling efficiencies in comparison with regularly spaced driver arrays; however, in the optimized arrays all of the modes within a specified frequency band may be independently addressed, which is important for achieving a desired loudspeaker frequency response. Experiments on flat panel loudspeakers with optimized force actuator array layouts show that each of the panel modes within a selected frequency band may be addressed independently and that the inter-modal crosstalk is typically −30 dB or less with non-ideal drivers.
Źródło:
Archives of Acoustics; 2017, 42, 1; 93-104
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectrum Aliasing Does Occur Only in Case of Non-ideal Signal Sampling
Autorzy:
Borys, Andrzej Marek
Powiązania:
https://bibliotekanauki.pl/articles/1844609.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal sampling
occurrence of spectrum aliasing and folding
signal modelling
non ideal signal sampling operation
Opis:
In this paper, it has been shown that the spectrum aliasing and folding effects occur only in the case of non-ideal signal sampling. When the duration of the signal sampling is equal to zero, these effects do not occur at all. In other words, the absolutely necessary condition for their occurrence is just a nonzero value of this time. Periodicity of the sampling process plays a secondary role.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 1; 79-85
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Rotation Methods in Sample Surveys in Poland
Autorzy:
Kordos, Jan
Powiązania:
https://bibliotekanauki.pl/articles/466006.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
Rotation sampling
sampling on successive occasions survey across time
panel survey
data quality
sample survey
Opis:
The author reviews theory and application of rotation methods in sample surveys in Poland. He begins with reviewing designs of the surveys across time, depending on different objectives, focusing on partial rotation of sub-samples, and considers estimation problems and data quality issues generally. Next, he refers to some articles and books about surveys published over time, starting with Wilks (1940), Patterson (1950), Eckler (1955), Woodruff (1963), Rao and Graham (1964), Bailar (1975), Duncan and Kalton (1987) and Kalton and Citro (1993). He mentions also early Polish papers on rotation methods (Kordos (1966, 1967, 1971, 1982); Lednicki, 1982; Szarkowski and Witkowski, 1994), and concentrates on Polish household surveys, mainly Household Budget Survey (HBS), Labour Force Survey (LFS) and EU Statistics on Living Conditions and Income (EU-SILC). Special attention is devoted to last research on rotation sampling done by Polish sampling statisticians: Ciepiela et al. (2012), Kordos (2002), Kowalczyk (2002, 2003, 2004), Kowalski (2006, 2009), Kowalski and Wesołowski (2012) and Wesołowski (2010). Concluding remarks are given at the end.
Źródło:
Statistics in Transition new series; 2012, 13, 2; 243-260
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating the population mean using a continuous sampling design dependent on an auxiliary variable
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/1059051.pdf
Data publikacji:
2020-12-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
continuous sampling design
Horvits-Thompson estimator
inclusion density
sampling scheme
bivariate gamma distribution
ratio estimator
Opis:
Continuous distribution of variables under study and auxiliary variables are considered. The purpose of the paper is to estimate the mean of the variable under study using a sampling design which is dependent on the observation of a continuous auxiliary variable in the whole population. Auxiliary variable values observed in this population allow to estimate the inclusion density function of the sampling design. The variance of the continuous version of the Horvitz-Thompson estimator under the proposed sampling design is compared with the variance of the mean of a simple random sample. The accuracy of the estimation strategies is analysed by means of simulation experiments.
Źródło:
Statistics in Transition new series; 2020, 21, 5; 1-16
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probabilistyczny model wyniku pomiaru wartości chwilowej wielkości zmiennej w czasie
Probabilistic model of instantaneous value measurement result of varying in time quantity
Autorzy:
Jakubiec, J.
Powiązania:
https://bibliotekanauki.pl/articles/156154.pdf
Data publikacji:
2005
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
sampling
quantizing
probabilistic error model
uncertainty
Opis:
W artykule rozpatrywane jest zagadnienie pomiaru wartości chwilowej wielkości zmieniającej się w czasie za pomocą toru pomiarowego składającego się z układu próbkująco/pamietającego oraz przetwornika A/C. Opisano sposób modelowania właściwości metrologicznych elementów toru oraz probabilistyczny model wyniku pomiaru uzyskiwanego na jego wyjściu. Przedstawiono metodę weryfikacji tego rodzaju modelu dla przypadku, gdy obejmuje on wiele źródeł błędu.
The paper characterizes the problem of instantaneous value measurement of a quantity varying in time by using a measuring chain consists of a Sample/Hold circuit and an AD converter. A method of metrological properties modeling of the chain elements and a model of measurement result obtained at the output of the chain has been presented. A verification method of such a kind model, for the situation when it contains many error sources, has been described.
Źródło:
Pomiary Automatyka Kontrola; 2005, R. 51, nr 2, 2; 28-31
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The variability of mechanical properties of the kohlrabi stalk parenchyma
Autorzy:
Starek, A.
Kusińska, E.
Powiązania:
https://bibliotekanauki.pl/articles/410825.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
kohlrabi
mechanical properties
place of sampling
Opis:
The paper presents the results of the impact of kohlrabi parenchyma sampling site on textural properties. Selected texture parameters, i.e. hardness, springinees, cohesiveness and chewiness were determined by the double compression test TPA. The study was conducted on samples taken from well-defined kohlrabi layers (upper layer, middle layer, lower layer) and zones (A, B, C), because the vegetable's structure is heterogeneous. The samples were compressedat the longitudinal and transverse orientation of the fibers relative to the movement of the working tool. The results were statistically analyzed using the program Statistica 8.0. The research has shown that the place of sampling and orientation of the fibers have a significant impact on the value of all the kohlrabi texture parameters.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2016, 5, 3; 9-18
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sample size in multilevel structural equation modeling – the Monte Carlo approach
Autorzy:
Sagan, Adam
Powiązania:
https://bibliotekanauki.pl/articles/424921.pdf
Data publikacji:
2019
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
sampling
multilevel SEM
Monte Carlo simulations
Opis:
In the process of sample selection, an important issue is the relationship between sample size and the type and complexity of the statistical model, which is the basis for testing research hypotheses. The paper presents methodological aspects of sample size determination in multilevel structural equation modelling (SEM) in the analysis of satisfaction with the banking products in Poland. The multilevel SEM results from the necessity to take into account both the sample size at the level of individual respondents, as well as at the higher level of analysis and the intraclass correlation coefficient. A comparison of factor loading bias based on the Monte Carlo simulation is made for different cluster sizes and the number of clusters.
Źródło:
Econometrics. Ekonometria. Advances in Applied Data Analytics; 2019, 23, 4; 63-79
1507-3866
Pojawia się w:
Econometrics. Ekonometria. Advances in Applied Data Analytics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Two-phase Sampling Strategy for Estimating Multiple Mean Values in the Presence of Nonresponse
Strategia losowania dwufazowego dla estymacji wartości przeciętnej wielu cech w obecności braków odpowiedzi
Autorzy:
Gamrot, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/904925.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
nonresponse
callbacks
subsampling
two-phase sampling
Opis:
The phenomenon of nonresponse in sample surveys usually results in biased estimates of population characteristics. One of the means to deal with nonresponse is the subsampling technique. It relies on re-contacting some subset of nonrespondents by using more expensive and more efficient tools (e.g. direct interview) than those used in the first attempt to collect data. This allows to increase response rate and to obtain unbiased estimates of population characteristics. In this paper, the problem of establishing the sample and subsample sizes minimizing the expected cost of the survey, while achieving desired precision of multiple mean value estimates, is considered. An algorithm is proposed that allows to establish the optimum initial sample and subsample sizes for two-phase sampling strategy.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2004, 175
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Useful Results Related with Sampling Theorem and Reconstruction Formula
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/963792.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sampling theorem
cardinal series
reconstruction formula
Opis:
In this paper, we present some useful results related with the sampling theorem and the reconstruction formula. The first of them regards a relation existing between bandwidths of interpolating functions different from a perfectreconstruction one and the bandwidth of the latter. Furthermore, we prove here that two non-identical interpolating functions can have the same bandwidths if and only if their (same) bandwidth is a multiple of the bandwidth of an original unsampled signal. The next result shows that sets of sampling points of two nonidentical (but not necessarily interpolating) functions possessing different bandwidths are unique for all sampling periods smaller or equal to a given period (calculated in a theorem provided). These results are completed by the following one: in case of two different signals possessing the same bandwidth but different spectra shapes, their sets of sampling points must differ from each other.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 3; 471-475
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Topological Aspects of Sampling Theorem and Reconstruction Formula
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/226041.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
topological issues
reconstruction formula
sampling theorem
Opis:
We present here a few thoughts regarding topological aspects of transferring a signal of a continuous time into its discrete counterpart and recovering an analog signal from its discrete-time equivalent. In our view, the observations presented here highlight the essence of the above transformations. Moreover, they enable deeper understanding of the reconstruction formula and of the sampling theorem. We also interpret here these two borderline cases that are associated with a time quantization step going to zero, on the one hand, and approaching its greatest value provided by the sampling theorem, on the other.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 2; 301-307
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using a particular sampling method for impedance measurement
Autorzy:
Lentka, G.
Powiązania:
https://bibliotekanauki.pl/articles/221836.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
impedance measurement
impedance analyzer
particular sampling
Opis:
The paper presents an impedance measurement method using a particular sampling method which is an alternative to DFT calculation. The method uses a sine excitation signal and sampling response signals proportional to current flowing through and voltage across the measured impedance. The object impedance is calculated without using Fourier transform. The method was first evaluated in MATLAB by means of simulation. The method was then practically verified in a constructed simple impedance measurement instrument based on a PSoC (Programmable System on Chip). The obtained calculation simplification recommends the method for implementation in simple portable impedance analyzers destined for operation in the field or embedding in sensors.
Źródło:
Metrology and Measurement Systems; 2014, 21, 3; 497-508
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analizy PVT jako skuteczne narzędzie w rękach inżyniera naftowego. Pobór wgłębnych próbek płynów złożowych do badań PVT
PVT analyses as an effective tool in the hands of the petroleum engineer. Downhole reservoir fluid sampling for PVT analysis
Autorzy:
Warnecki, Marcin
Wojnicki, Mirosław
Kuśnierczyk, Jerzy
Szuflita, Sławomir
Powiązania:
https://bibliotekanauki.pl/articles/1833918.pdf
Data publikacji:
2020
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
PVT
pobór wgłębny
zmiany fazowe
wgłębny pobór płynów złożowych
downhole sampling
phase behavior
reservoir fluid sampling
Opis:
The most important aspect of laboratory analysis is undoubtedly to acquire data of the highest quality. The worldwide trend of drilling into deeper reservoirs characterised by the high temperature and high pressure (HTHP) conditions makes the newly discovered reservoirs challenging because of bearing fluids with an unprecedented diversity of phase behaviour and variability of phase parameters over time. Due to the high temperature of the deep horizons constituting the reservoir rock, many individual components of the reservoir fluids are located in a region close to their critical temperatures, i.e. gas condensate (retrograde condensation region) or volatile oil. In particular, gas condensate reservoirs are challenging to analyse. They are highly prone to the errors resulting from phase behaviour testing when using samples that are incompatible with the original reservoir in-situ fluid that saturates the reservoir rock pores. Taking the representative samples of reservoir fluid is an essential requirement to obtain reliable data that can characterise such phase-variable multicomponent reservoirs. The primary purpose of hydrocarbon fluid analysis in case of new discoveries is to determine the type of reservoir fluid system. It should also be borne in mind that without a sufficiently long production process from several intervals and/or several wells, it can be challenging to classify the fluid with confidence, especially at the initial analysis stage. The paper presents issues related to sampling of the reservoir fluid (such as crude oil and natural gas) for the physical property and phase behaviour analyses (PVT), usually accompanied by chemical analyses. The importance of representativeness of the samples in performing reliable tests that have a significant impact on the hydrocarbon production was discussed. The data obtained from the PVT laboratory are widely used in economic reports concerning local, regional or finally national hydrocarbon reserves. Other applications of the PVT data include coordination of reservoir exploitation methods related to a particular fluid composition, as well as input to design requirements for the surface facilities development, and selection of the suitable technology for hydrocarbon fluid treatment prior to introduction to the market. Various techniques of downhole sampling were mentioned and characterised with an explanation of their applicability. The criteria for selection of a proper method were also presented.
Źródło:
Nafta-Gaz; 2020, 76, 11; 784--793
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved Estimators for Simple Random Sampling and Stratified Random Sampling under Second Order of Approximation
Autorzy:
Sharma, Prayas
Powiązania:
https://bibliotekanauki.pl/articles/465938.pdf
Data publikacji:
2014
Wydawca:
Główny Urząd Statystyczny
Tematy:
simple random sampling
stratified random sampling population mean
study variable
exponential ratio type estimators
bias and MSE
Opis:
Singh and Solanki (2012) and Koyuncu (2012) proposed estimators for estimating population meanY. Up to the first order of approximation and under optimum conditions, the minimum mean squared error of both the estimators is equal to the MSE of the regression estimator. In this paper, we have tried to find out the second order biases and mean square errors of these estimators using information on auxiliary variable based on simple random sampling. Finally, we have compared the performance of these estimators with some numerical illustration.
Źródło:
Statistics in Transition new series; 2014, 15, 3; 379-390
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal allocation for equal probability two-stage design
Autorzy:
Molefe, Wilford
Powiązania:
https://bibliotekanauki.pl/articles/2156993.pdf
Data publikacji:
2022-12-15
Wydawca:
Główny Urząd Statystyczny
Tematy:
sample designs
optimal allocation
composite estimation
mean squared error
two-stage sampling
simple random sampling without replacement
Opis:
This paper develops optimal designs when it is not feasible for every cluster to be represented in a sample as in stratified design, by assuming equal probability two-stage sampling where clusters are small areas. The paper develops allocation methods for two-stage sample surveys where small-area estimates are a priority. We seek efficient allocations where the aim is to minimize the linear combination of the mean squared errors of composite small area estimators and of an estimator of the overall mean. We suggest some alternative allocations with a view to minimizing the same objective. Several alternatives, including the area-only stratified design, are found to perform nearly as well as the optimal allocation but with better practical properties. Designs are evaluated numerically using Switzerland canton data as well as Botswana administrative districts data.
Źródło:
Statistics in Transition new series; 2022, 23, 4; 129-148
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of non-ideal signal sampling via averaging operation and spectrum of sampled signal predicted by this model
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/2172501.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
modelling of non-Ideal signal sampling
non-Ideal signal
spectrum of sampled signal
A/D converters
non-Ideal signal sampling
signal sampling
discrete time fourier transform
Opis:
In this paper, a novel model of a non-ideal signal sampling via a local, periodic averaging operation is present-ed. The spectrum of a sampled signal predicted by this model is also analysed as well as compared with a one following from another model.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2022, 16, 2; 274--278
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ensuring the reliability and reduction of quality control costs by minimizing process variability
Autorzy:
Rogalewicz, Michał
Kujawińska, Agnieszka
Feledziak, Adrianna
Powiązania:
https://bibliotekanauki.pl/articles/24200827.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
quality inspection
reliability
quality cost
sampling inspection
Opis:
This paper presents a method for planning the range of quality control while ensuring its reliability and minimizing costs. The method is dedicated to destructive inspection, in which the cost of performing the measurement is significant in relation to the cost of manufacturing a part or product. The methodology was divided into four main stages: (1) selection of the measurement system and definition of the inspection scope and sample size, (2) process control, (3) redefining the scope of control and (4) verification of control cost and reliability after sample size change. The article presents the results of applying the author's procedure to the process of evaluating seat belts in automotive industry. Belts are used in the process of controlling the final product, which is a seat belt anchor plate. This approach allowed to reduce the number of destroyed parts during control while maintaining the credibility of the decision based on the assessment. As a result of double-decreasing the sample size, the costs of seat belt quality control were reduced. Assuming an average of 40 seat belt deliveries per year, the material cost was reduced by 50%. Limiting the sample size to 15 pieces per delivery would reduce the cost of testing from by 45%. It was achieved maintaining the appropriate level of credibility of decisions made greater than 0.8.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 162626
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Measurement Error Using Local Sampling and Joint Nonparametric Linearisation
Estymowanie błędu pomiarowego z zastosowaniem łącznej nieparametrycznej linearyzacji prób lokalnych
Autorzy:
Górkiewicz, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/906540.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
local sampling
linearisation
measurement error
neear neighbours
Opis:
This paper presents how to use the near neighbours technique in aim to transform a given data set (Z, X, YT) of size N into a set of J ~ N local samples (Z, X), with restrictions on minimal number К of members in each local sample and on maximal difference of Y inside each local sample, where Z plays role of an outcome, X is an independent variable, and Y1 - (Y ..., YL) is a vector of L supplementary continuous variables. Then the procedure for non-parametric joint linearisation of an obtained set of local samples was proposed. The whole proposed method was applied to estimation of models with standard deviation of measurements as outcome Z and measured value as independent variable X. The paper was inspired by difficulties with estimation of the measurement error, which often occur in medicine, if accuracy of a measurement procedure depends on some properties of patient. Nevertheless, the proposed approach seems to be more general. It can be useful in many analyses of observational studies, which aim to estimate a family of the functions, preferable the linear ones, instead a single multivariate model.
Praca prezentuje zastosowanie techniki najbliższych sąsiadów w celu przekształcenia zbioru N danych postaci (Z, X, YT) w zbiór J ~ N prób lokalnych (Z, X), przy ograniczeniach dotyczących minimalnej liczby danych К oraz różnic wartości YT w każdej próbie lokalnej, gdzie Z pełni rolę zmiennej zależnej, X - zmiennej niezależnej, a Y1 = (Y, ..., YL) jest L-wymiarową zmienną dodatkową. Następnie proponuje się procedurę nieparametrycznej łącznej linearyzacji zbioru prób lokalnych. Obie procedury proponuje się stosować do oceny dokładności metod pomiarowych, z odchyleniem standardowym błędu pomiarów jako zmienną Z i wielkością mierzoną jako zmienną X. Proponowane podejście może być użyteczne w innych zastosowaniach, kiedy zamiast modelu regresji wielowymiarowej estymuje się rodzinę zależności regresyjnych.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2002, 162
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric prediction of finite population total under Informative sampling and nonignorable nonresponse
Autorzy:
Abdulhakeem, Eideh
Powiązania:
https://bibliotekanauki.pl/articles/1358422.pdf
Data publikacji:
2020-03-23
Wydawca:
Główny Urząd Statystyczny
Tematy:
response distribution
nonignorable nonresponse
informative sampling design
Opis:
In this paper, we combine two methodologies used in the model-based survey sampling, namely the prediction of the finite population total, named T, under informative sampling and full response, see Sverchkov and Pfeffermann (2004), and the prediction of T with a noninformative sampling design and the nonignorable nonresponse mechanism, see Eideh (2012). The former approach involves the dependence of the first order inclusion probabilities on the study variable, while the latter involves the dependence of the probability of nonresponse on unobserved or missing observations. The main aim of the paper is to consider how to account for the joint effects of informative sampling designs and notmissing- at-random response mechanism in statistical models for complex survey data. For this purpose, theoretically, we use the response distribution and relationships between the moments of the superpopoulation, the sample, sample-complement, response, and nonresponse distributions for the prediction of finite population totals, see Eideh (2016). The derived parametric predictors of T use the observation for the response set of the study variable or variable of interest, values of auxiliary variables and their population totals, sampling weights, and propensity scores. An interesting outcome of the T study is that most predictors known from model-based survey sampling can be derived as a special case from this general theory, see Chambers and Clark (2012).
Źródło:
Statistics in Transition new series; 2020, 21, 1; 13-35
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rola statystyki w życiu społeczeństwa i funkcjonowaniu państwa
The role of statistics for society and the functioning of the state
Autorzy:
Iwasiewicz, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/528349.pdf
Data publikacji:
2011
Wydawca:
Krakowska Akademia im. Andrzeja Frycza Modrzewskiego
Tematy:
statistics
survey sampling
sampling techniques
sampling methods
advetising research
consumer price index (CPI)
producer price index (PPI)
demography
statystyka
badania sondażowe
metoda reprezentacyjna
wskaźniki inflacji (CPI, PPI)
demografia
Źródło:
Państwo i Społeczeństwo; 2011, 2; 105-132
1643-8299
2451-0858
Pojawia się w:
Państwo i Społeczeństwo
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performing quantiles in multiple regression sampling strategy
Ocena wartości przeciętnej za pomocą regresyjnej strategii losowania wykorzystującej kwantyle zmiennej pomocniczej
Autorzy:
Wywiał, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/907013.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
sampling design
order statistic
sample quantile
auxiliary variable
Horvitz-Thompson statistic
inclussion probabilities
sampling scheme
regression estimator
Opis:
Estimation of the population average in a finite population by means of sampling strategy dependent on the sample quantile of an auxiliary variables is considered. The sampling design is proportionate to the determinant of the matrix dependent on some quantiles of an auxiliary variables. The sampling scheme implementing the sampling design is proposed. The derived inclusion probabilities are applied to estimation the population mean using the well known Horvitz-Thompson estimator. Moreover, the regression estimator is defined as the function of the coefficient dependent on the quantiles of the auxiliary variables. The properties of this estimator under the above defined sampling design are studied. The considerations are supported by empirical examples.
Problem oceny wartości średniej z wykorzystaniem danych o wszystkich wartościach cech pomocniczych jest rozważany. W tym celu znany estymator regresyjny zależny od wielu zmiennych pomocniczych jest wykorzystywany. W odróżnieniu od zwykłego podejścia znanego w metodzie reprezentacyjnej do oceny parametrów regresji są wykorzystywane kwantyle jednej ze zmiennych dodatkowych. Otrzymane na tym polu wyniki są adoptowane do konstrukcji predytorów wartości średniej w nadpopulacji. Wyprowadzono również wariancje różnych odmian proponowanych predykatorów.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2008, 216
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Another Proof of Ambiguity of the Formula Describing Aliasing and Folding Effects in Spectrum of Sampled Signal
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2055252.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal sampling
occurrence of spectrum aliasing and folding
modelling of non-ideal signal sampling operation
Vetterli's model
Opis:
In this paper, a new proof of ambiguity of the formula describing the aliasing and folding effects in spectra of sampled signals is presented. It uses the model of non-ideal sampling operation published by Vetterli et al. Here, their model is modified and its black-box equivalent form is achieved. It is shown that this modified model delivers the same output sequences but of different spectral properties. Finally, a remark on two possible understandings of the operation of non-ideal sampling is enclosed as well as fundamental errors that are made in perception and description of sampled signals are considered.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 1; 115--122
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sampling Designs Proportionate to Sum of Two Order Statistics of Auxiliary Variable
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/465790.pdf
Data publikacji:
2013
Wydawca:
Główny Urząd Statystyczny
Tematy:
sampling design
order statistic
sample quantile
auxiliary variable
Horvitz-Thompson statistic
inclusion probabilities
sampling scheme
ratio estimator
Opis:
In this paper the case of a conditional sampling design proportional to the sum of two order statistics is considered. Several strategies including the Horvitz-Thompson estimator and ratio-type estimators are discussed. The accuracy of these estimators is analyzed on the basis of computer simulation experiments.
Źródło:
Statistics in Transition new series; 2013, 14, 2; 231-248
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectrum Aliasing Does not Occur in Case of Ideal Signal Sampling
Autorzy:
Borys, Andrzej Marek
Powiązania:
https://bibliotekanauki.pl/articles/1844614.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal sampling
occurrence of spectrum aliasing and folding
signal modelling
signal sampling operation
Kronecker time function
Kronecker comb
Opis:
A new model of ideal signal sampling operation is developed in this paper. This model does not use the Dirac comb in an analytical description of sampled signals in the continuous time domain. Instead, it utilizes functions of a continuous time variable, which are introduced in this paper: a basic Kronecker time function and a Kronecker comb (that exploits the first of them). But, a basic principle behind this model remains the same; that is it also a multiplier which multiplies a signal of a continuous time by a comb. Using a concept of a signal object (or utilizing equivalent arguments) presented elsewhere, it has been possible to find a correct expression describing the spectrum of a sampled signal so modelled. Moreover, the analysis of this expression showed that aliases and folding effects cannot occur in the sampled signal spectrum, provided that the signal sampling is performed ideally.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 1; 71-77
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
THE ACCEPTANCE CONTROL COSTS FOR VARIABLE SAMPLING IN CASE OF DISTRIBUTION OF CHARACTERISTIC INCOMPATIBLE WITH ASSUMPTIONS
KOSZTY KONTROLI ODBIORCZEJ DLA LICZBOWEJ OCENY WŁAŚCIWOŚCI PRZY NIEZGODNOŚCI ROZKŁADU CHARAKTERYSTYKI Z ZAŁOŻENIAMI
Autorzy:
Chmielińska, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/654511.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
Statystyczna kontrola jakości
kontrola według oceny liczbowej
koszty kontroli odbiorczej
Statistical quality control
variable sampling
acceptance sampling costs
Opis:
Plan odbiorczy jest procedurą rozstrzygania na podstawie próby losowo pobranej z większej partii o jakości w tej badanej partii. Kontrola odbiorcza prowadzona może być zarówno w oparciu o ocenę alternatywną, jak i w oparciu o ocenę właściwości liczbowych. Plan kontroli odbiorczej oparty na ocenie właściwości liczbowych zakłada, iż kontrolowana charakterystyka ma rozkład normalny. W artykule zostanie zaprezentowana procedura wyznaczania stałej k liczbowego planu odbiorczego o zadanej liczebności próbki i ryzyku producenta, w przypadku rozkładu kontrolowanej charakterystyki istotnie różnego od rozkładu normalnego. W artykule porównano proponowaną metodę z metodą klasyczną pod względem generowanych kosztów. Założono, iż w przypadku rozkładów istotnie różnych od rozkładu normalnego, proponowana metoda okaże się tańsza w stosowaniu. 
The acceptance sampling is the settlement procedure based on a sample randomly selected from a larger batch of quality in the controlled batch. The inspection can be run in case of variable assessment and attribute assessment. Variable sampling assumes that the parameter of quality characteristic follows the normal distribution. In paper will be presented the procedure of determining the acceptance constant k of acceptance sampling by set sample size and risk of the producer, in the case of distribution of a controlled characteristics significantly different from the normal distribution. In the article the proposed method with the classical method in terms of the generated costs, is compared. It was assumed that in the case of distributions significantly different from normal distribution, the proposed method proves to be cheaper in the application.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2015, 3, 314
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Addressing the problem of lack of representativeness on syndromic surveillance schemes
Autorzy:
Natário, Isabel
Lucília Carvalho, M.
Powiązania:
https://bibliotekanauki.pl/articles/729974.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
syndromic surveillance
state space models
importance sampling
Opis:
A major concern with some contagious diseases has recently led to an enormous effort to monitor population health status by several different means.
This work presents a modeling approach to overcome this poor data characteristic, allowing its use for the estimation of the true population disease picture. We use a state space model, where we run two processes in parallel - a process describing the non observable states of the population concerning the presence/absence of disease, and an observational process resulting from the monitoring.
We then use resampling importance sampling estimation techniques, in a Bayesian framework, which enables us to estimate the population states and, thus, the corresponding disease incidence curves.
Źródło:
Discussiones Mathematicae Probability and Statistics; 2009, 29, 2; 169-183
1509-9423
Pojawia się w:
Discussiones Mathematicae Probability and Statistics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CZY MOŻNA POŁĄCZYĆ ILOŚĆ Z JAKOŚCIĄ? MOŻLIWOŚCI I BARIERY PODEJŚCIA ILOŚCIOWEGO W BADANIACH INTEGRACJI MIGRANTÓW W POLSCE
ARE QUANTITY AND QUALITY POSSIBLE TO COMBINE? OPPORTUNITIES AND CONSTRAINTS OF QUANTITATIVE RESEARCH ON MIGRANT INTEGRATION IN POLAND
Autorzy:
Górny, Agata
Torunczyk-Ruiz, Sabina
Powiązania:
https://bibliotekanauki.pl/articles/580277.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
QUANTITATIVE STUDIES
IMMIGRATION TO POLAND
INTEGRATION
SAMPLING
Opis:
The article is devoted to the opportunities and the constraints of the quantitative approach in studying migrant integration in Poland. It is argued that taking into account the specific character of the inflow of foreigners to Poland, the small number of migrants and temporariness of mobility, some special methodological solutions are needed, regarding mainly the sampling procedures. At the same time, it is claimed that the representativeness of the results should be targeted. Taking into account the existing limitations, the article recommends first of all quantitative studies of selected groups of migrants and areas where they are present. The methodological reflections demonstrated in the article are based on two quantitative research projects conducted by the Centre of Migration Research, University of Warsaw.
Źródło:
Studia Migracyjne - Przegląd Polonijny; 2011, 37, 2(140); 41-58
2081-4488
2544-4972
Pojawia się w:
Studia Migracyjne - Przegląd Polonijny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sampling Rate Impact on the Tuning of PID Controller Parameters
Autorzy:
Laskawski, M.
Wcislik, M.
Powiązania:
https://bibliotekanauki.pl/articles/226068.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PID controllers
tuning
optimal control
sampling rate
Opis:
The paper deals with an analysis of automatic control system with continuous and discrete PID controllers. A method of tuning the parameters of the continuous controller is presented, which is optimal according to the ITAE criterion. The behavior of control systems with discrete controllers whose parameters were tuned using the mentioned method are described. The impact of changes in the sampling period of controlled signal on the control quality is shown. Changes of the values of optimal parameters of discrete PID controllers in relation to changes of the sampling rate of controlled signal are characterized.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 1; 43-48
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Filtering Property of Signal Sampling in General and Under-Sampling as a Specific Operation of Filtering Connected with Signal Shaping at the Same Time
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/226441.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signal sampling
filtering
discrete-time Fourier transform
Opis:
In this paper, we show that signal sampling operation can be considered as a kind of all-pass filtering in the time domain, when the Nyquist frequency is larger or equal to the maximal frequency in the spectrum of a signal sampled. We demonstrate that this seemingly obvious observation has wide-ranging implications. They are discussed here in detail. Furthermore, we discuss also signal shaping effects that occur in the case of signal under-sampling. That is, when the Nyquist frequency is smaller than the maximal frequency in the spectrum of a signal sampled. Further, we explain the mechanism of a specific signal distortion that arises under these circumstances. We call it the signal shaping, not the signal aliasing, because of many reasons discussed throughout this paper. Mainly however because of the fact that the operation behind it, called also the signal shaping here, is not a filtering in a usual sense. And, it is shown that this kind of shaping depends upon the sampling phase. Furthermore, formulated in other words, this operation can be viewed as a one which shapes the signal and performs the low-pass filtering of it at the same time. Also, an interesting relation connecting the Fourier transform of a signal filtered with the use of an ideal low-pass filter having the cut frequency lying in the region of under-sampling with the Fourier transforms of its two under-sampled versions is derived. This relation is presented in the time domain, too.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 3; 589-594
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pobieranie próbek gleby w kontekście prowadzenia oceny zanieczyszczenia powierzchni ziemi
Soil sampling in the context of land surface pollution assessment
Autorzy:
Gajec, M.
Król, A.
Kukulska-Zając, E.
Mostowska-Stąsiek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1835187.pdf
Data publikacji:
2018
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
pobieranie próbek
gleba
niepewność
sampling
soil
uncertainty
Opis:
W artykule omówiono prawodawstwo w zakresie pobierania próbek gleby, obowiązujące podczas prowadzenia oceny zanieczyszczenia powierzchni ziemi. Dokonany przegląd pokazał, że na szczeblu unijnym problem regulacji prawnej związanej z ochroną gleb został dostrzeżony, lecz nadal nie doszło do wprowadzenia jednej dyrektywy poruszającej ten temat. W przypadku regulacji krajowych istnieje rozporządzenie podejmujące zagadnienia związane z pobieraniem próbek gleb w celu dokonania oceny zanieczyszczenia powierzchni ziemi, która powinna być prowadzona na podstawie wiarygodnych wyników wraz z oszacowaną niepewnością, uwzględniającą wszystkie kluczowe składowe. Zaprezentowano wyniki badań otrzymane dla próbek gleby, pobranych zgodnie z omówionymi regulacjami prawnymi. Na podstawie wyników analiz czterech parametrów otrzymanych dla próbek pobranych zgodnie z projektem zrównoważonym (polegającym na wykonaniu dwukrotnych analiz dla dwukrotnie pobranych próbek z ośmiu obiektów), oszacowano niepewność procesu oraz jej składowe (stosując analizę wariancji robust ANOVA). Najbardziej znaczącym udziałem w oszacowanej niepewności procesu (Umeas) była niepewność pochodząca z etapu pobierania próbek.
The article discusses the legislation in the field of soil sampling, which is obligatory during the assessment of soil surface pollution. The review showed that at the EU level, the problem of legal regulation related to soil protection has been noticed, but a single directive dealing with soil protection has not yet been implemented. In the case of national regulations, there is one that deals with issues related to the sampling of soils in order to assess the pollution of the Earth surface. The assessment of ground contamination should be based on reliable results together with estimated uncertainty, which takes into account all key components. The results of the tests obtained for the soil samples that have been collected according to mentioned legal regulations have been presented and discussed. The article shows the results of empirical methodology (robust ANOVA) using data from balanced experimental design, which includes duplicate samples analyzed in duplicate from 8 sampling targets. Robust ANOVA methodology is used for the estimation of the uncertainty arising from the manual sampling of soils and determination of four tested parameters. Based on the results of the study, it was found that the most significant contribution to the estimated uncertainty of the process (Umeas), was the uncertainty arising from sampling.
Źródło:
Nafta-Gaz; 2018, 74, 3; 215-225
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nowy, zremiksowany świat [rec. David J. Gunkel: Of Remixology. Ethics and Aesthetics After Remix. Cambridge: MIT Press, 2016, ss. 240.]
A New Remixed World [re: D.J. Gunkel: Of Remixology. Ethics and Aesthetics After Remix]
Autorzy:
Marcela, Mikołaj
Powiązania:
https://bibliotekanauki.pl/articles/534921.pdf
Data publikacji:
2018
Wydawca:
Wydawnictwo Uniwersytetu Śląskiego
Tematy:
remix
sampling
mash-up
deconstruction
copyright rights
Opis:
According to many researchers and theoreticians mentioned by Davis J. Gunkel we live today in digital culture of “mash-up”, which is at the same time configurable convergence culture. Therefore in the contemporary world the concept of remix enjoys such great popularity. It is in sampling and remixing that “the cultural logic of networked global capitalism” should be sought. However, the mentioned terms occur mainly in the disputes over copyright laws and freedom of the access to culture. For Gunkel this aspect is not a key one. In Of Remixology he suggests a departure from the current way of thinking about remix in terms of an original and a copy, innovation and derivation, authorship and plagiarism. Instead, Gunkel proposes the third way of thinking, where his companions become such theoreticians as Jacques Derrida, Roland Barthes, Jean Baudrillard and Slavoj Žižek.
Źródło:
Śląskie Studia Polonistyczne; 2018, 11, 1; 203-210
2084-0772
2353-0928
Pojawia się w:
Śląskie Studia Polonistyczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Legalność samplingu muzycznego w świetle polskiego prawa autorskiego
The legality of music sampling in Polish copyright law
Autorzy:
Maryniak, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/28783055.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
sampling
music
copyright
quote
muzyka
prawa autorskie
cytat
Opis:
Jak wskazał Lawrence Lessig, żyjemy w czasach „kultury remiksu” – powszechny dostęp do Internetu, a przez to do wielu dóbr kultury, sprawia, że artyści często przerabiają lub w inny sposób wykorzystują twórczość innych osób. Jest to szczególnie widoczne w muzyce. Celem niniejszego artykułu jest wykazanie, że sampling muzyczny jest co do zasady zgodny z polskim prawem autorskim. W badaniach wykorzystano przede wszystkim metodę dogmatyczną, dokonując analizy przepisów ustawy o prawie autorskim i prawach pokrewnych regulujących pojęcia utworu i inspiracji oraz instytucję prawa cytatu. We wnioskach wskazano, że sampling muzyczny w wielu przypadkach nie narusza prawa autorskiego, ponieważ polega na wykorzystaniu nietwórczego (niechronionego) fragmentu utworu pierwotnego. Natomiast w pozostałych sytuacjach, tzn. wtedy gdy uzna się, że dany sampel jest jednak objęty ochroną prawnoautorską, przeważnie dopuszczalne będzie jego wykorzystywanie w ramach prawa cytatu. Niemniej powyższe twierdzenia nie oznaczają, że sampling stanowi w każdym przypadku działanie etyczne lub moralnie uzasadnione.
As Lawrence Lessig pointed out, we live in times of ‘remix culture’ – as a result of universal access to the Internet, and thus to many cultural goods, artists often remake or otherwise use the work of other people. This is especially common in music. The purpose of this article is to show that music sampling is generally compliant with Polish copyright law. The research mainly used the dogmatic method, analysing the provisions of the Act on Copyright and Related Rights regulating the concepts of work and inspiration, as well as the institution of the right to quote. The conclusions indicate that music sampling in many cases does not infringe copyright because it consists in the use of a non-creative (unprotected) fragment of the original work. In other situations, when it is considered that a given sample is protected by copyright protection, it will usually be permissible to use it under the right to quote. Nevertheless, the above statements do not mean that sampling is always ethical or morally justified.
Źródło:
Ruch Prawniczy, Ekonomiczny i Socjologiczny; 2022, 84, 4; 121-136
0035-9629
2543-9170
Pojawia się w:
Ruch Prawniczy, Ekonomiczny i Socjologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of sampling methods on the results of quantitative studies on molluscs of S Baltic
Autorzy:
Warzocha, J.
Powiązania:
https://bibliotekanauki.pl/articles/83620.pdf
Data publikacji:
1999
Wydawca:
Uniwersytet Mikołaja Kopernika. Wydział Biologii i Ochrony Środowiska. Stowarzyszenie Malakologów Polskich
Tematy:
sampling method
quantitative study
mollusc
Baltic Sea
locality
Źródło:
Folia Malacologica; 1999, 07, 4
1506-7629
Pojawia się w:
Folia Malacologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SAMPLE ALLOCATION IN ESTIMATION OF PROPORTION IN A FINITE POPULATION DIVIDED INTO TWO STRATA: AN EXAMPLE OF APPLICATION
Autorzy:
Sieradzki, Dominik
Zieliński, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/453168.pdf
Data publikacji:
2018
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Katedra Ekonometrii i Statystyki
Tematy:
survey sampling
sample allocation
stratification
estimation
election poll
Opis:
The problem of estimating a proportion of objects with particular attribute in a finite population is considered. This paper shows an example of the application of estimation fraction using new proposed sample allocation in a population divided into two strata. Variance of estimator of the proportion which uses proposed sample allocation is compared to variance of the standard one. In the paper an application of sample allocation described in Sieradzki & Zieliński [2017] is presented."
Źródło:
Metody Ilościowe w Badaniach Ekonomicznych; 2018, 19, 1; 71-77
2082-792X
Pojawia się w:
Metody Ilościowe w Badaniach Ekonomicznych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza jakości sygnału przy zmiennej częstotliwości w układzie kontroli poślizgu kół ciągnika rolniczego
Analysis of signal quality at varying frequency in the system of control of skid of farm tractor wheels
Autorzy:
Cieślikowski, B.
Długosz, A.
Knaga, J.
Powiązania:
https://bibliotekanauki.pl/articles/286879.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
częstotliwość próbkowania
częstotliwość sygnału
sampling frequency
signal frequency
Opis:
W pracy przedstawiono badanie wpływu częstotliwości próbkowania na jakość sygnału wyjściowego z czujników. Określono również błąd względny zmiany częstotliwości sygnału odniesiony do częstotliwości pierwotnej (2 KHz).
The work presents the analysis of the impact of sampling frequency on the quality of the output signal from sensors. The relative error of change of signal frequency referred to original frequency (2 KHz) was also determined.
Źródło:
Inżynieria Rolnicza; 2010, R. 14, nr 4, 4; 29-36
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementacja uogólnionego algorytmu szczególnego próbkowania dla wyznaczania harmonicznej podstawowej w środowisku LabVIEW
Implementation of generalized particular sampling algorithm for determining the fundamental harmonic in LabVIEW environment
Autorzy:
Ziółko, M.
Powiązania:
https://bibliotekanauki.pl/articles/267594.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
wyższe harmoniczne
próbkowanie
filtracja
filtering
harmonics
particular sampling
Opis:
Praca dotyczy opisu oraz implementacji uogólnionego algorytmu szczególnego próbkowania dla wyznaczania amplitudy harmonicznej podstawowej w środowisku LabVIEW. Algorytm szczególnego próbkowania umożliwia wyodrębnienie informacji o wartości amplitudy harmonicznej podstawowej ze spróbkowanego, odkształconego sygnału przy zastosowaniu stosunkowo prostych środków technicznych. Aplikacja może mieć zastosowanie w urządzeniach pomiarowych wyposażonych w prosty mikrokontroler. Zaleta opracowanego oprogramowania jest jego elastyczność, polegającą na automatycznym doborze zestawu próbek niezbędnych do filtracji wyższych harmonicznych, spełniającym zadeklarowane przez użytkownika wymagania.
The paper presents an implementation of generalized Particular Sampling Algorithm for determination the fundamental harmonic in LabVIEW environment. This algorithm is used to extract information about fundamental harmonic from distorted sampling signal. Information about the fundamental harmonic of current or voltage is substantial in many types of measurements. For example, some parameters in the protective measures in the power systems, like loop impedance or ground impedance, are calculated using such information. These parameters are very important in evaluation of effectiveness of protection against electric shocks. Extracted information about the fundamental harmonic with the application of Particular Sampling Method is possible using simplified technical resources compared to FFT algorithm. The measurement device based on Particular Sampling Method can be equipped with a simple microcontroller. In the literature a concrete implementations of this method were used. The sampling program, which was created so far manually, has been determined by the set of eliminated harmonics. The main advantage of presented software developed in LabVIEW environment is its flexibility, i.e. the sampling program is created automatically. The results obtained from the use of this software are consistent with the results of previous studies.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2013, 34; 81-84
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Synchronization Method for Transmission Systems with Variable Length of Bits
Autorzy:
Godek, J.
Golański, R.
Kołodziej, J.
Stępień, J.
Powiązania:
https://bibliotekanauki.pl/articles/226590.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
delta modulation
adaptation
non-uniform sampling
synchronization
codec
Opis:
Based on the Spartan 3E evaluation module, a flexible platform for the implementation of different algorithms for A/D conversion was developed. The aim of presented work was to improve the concept of the sampling rate adaptation to the input signal rate of change in terms of practical issues including synchronization of delta codecs. The new, original synchronization method, useful in systems dedicated for transmission of variable duration of bits was proposed and experimentally verified. Performed measures and observations have shown elimination of the synchronization lose phenomenon.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 1; 31-36
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Finite Population Mean Using Deciles of an Auxiliary Variable
Autorzy:
Subramani, J.
Kumarapandiyan, G.
Powiązania:
https://bibliotekanauki.pl/articles/466087.pdf
Data publikacji:
2013
Wydawca:
Główny Urząd Statystyczny
Tematy:
mean squared error
natural populations
simple random sampling
Opis:
The present paper deals with a class of modified ratio estimators for estimation of population mean of the study variable when the population deciles of the auxiliary variable are known. The biases and the mean squared errors of the proposed estimators are derived and compared with that of existing modified ratio estimators for certain known populations. Further, we have also derived the conditions for which the proposed estimators perform better than the existing modified ratio estimators. From the numerical study it is also observed that the proposed modified ratio estimators perform better than the existing modified ratio estimators.
Źródło:
Statistics in Transition new series; 2013, 14, 1; 75-88
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active power measurements - an overview and comparison of DSP algorithms by noncoherent sampling
Autorzy:
Sedlacek, M.
Stoudek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/220475.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
power estimation
digital signal processing
non-coherent sampling
Opis:
This paper presents an overview of algorithms for one-phase active power estimation using digital signal processing in the time domain and in the frequency domain, and compares the properties of these algorithms for a sinusoidal test signal. The comparison involves not only algorithms that have already been published, but also a new algorithm. Additional information concerning some known algorithms is also included. We present the results of computer simulations in MATLAB and measurement results gained by means of computer plug-in boards, both multiplexed and using simultaneous signal sampling. The use of new cosine windows with a recently published iterative algorithm is also included, and the influence of additive noise in the test signal is evaluated.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 173-184
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal random sampling for spectrum estimation in DASP applications
Autorzy:
Tarczyński, A.
Qu, D.
Powiązania:
https://bibliotekanauki.pl/articles/908447.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
cyfrowe przetwarzanie sygnału
próbkowanie losowe
analiza spektralna
próbkowanie optymalne
digital alias-free signal processing
random sampling
spectral analysis
optimal sampling
Opis:
In this paper we analyse a class of DASP (Digital Alias-free Signal Processing) methods for spectrum estimation of sampled signals. These methods consist in sampling the processed signals at randomly selected time instants. We construct estimators of Fourier transforms of the analysed signals. The estimators are unbiased inside arbitrarily wide frequency ranges, regardless of how sparsely the signal samples are collected. In order to facilitate quality assessment of the estimators, we calculate their standard deviations. The optimal sampling scheme that minimises the variance of the resulting estimator is derived. The further analysis presented in this paper shows how sampling instant jitter deteriorates the quality of spectrum estimation. A couple of numerical examples illustrate the main thesis of the paper
Źródło:
International Journal of Applied Mathematics and Computer Science; 2005, 15, 4; 463-469
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation analysis of accuracy estimation of population mean on the basis of regression type strategy dependent on order statistic of auxiliary variable
Autorzy:
Wywiał, Janusz L
Powiązania:
https://bibliotekanauki.pl/articles/658095.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
sampling design
order statistic
auxiliary variable
sampling scheme
estimation
strategy
accuracy comparison
relative efficiency
regression estimator
Horvitz-Thomson estimator
Opis:
Problem dotyczy oceny wartości średnie (globalnej) zmiennej w populacji ustalonej I skończonej. Zakład się, że z góry są znane w populacji wartości dodatniej zmiennej pomocniczej. Do estymacji użyto strategia kwantylowej zależnej m.in. od planu losowania proporcjonalnego do nieujemnej funkcji kwantyla z próby zmiennej pomocniczej. Ponadto, brano pod uwagę estymator Horvitza- Thompsona oraz estymator ilorazowy. Porównanie dokładności przeprowadzono na podstawie symulacji komputerowej.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2011, 255
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Mean on The Basis of Conditional Simple Random Sample
Autorzy:
Wywiał, Janusz L.
Powiązania:
https://bibliotekanauki.pl/articles/466050.pdf
Data publikacji:
2016
Wydawca:
Główny Urząd Statystyczny
Tematy:
conditional sampling design
order statistic
concomitant
sample quantile
auxiliary variable
Horvitz-Thompson statistic
inclusion probabilities
sampling scheme
ratio estimator
Opis:
Estimation of the population mean in a finite and fixed population on the basis of the conditional simple random sampling design dependent on order statistics (quantiles) of an auxiliary variable is considered. Properties of the well-known Horvitz-Thompson and ratio type estimators as well as the sample mean are taken into account under the conditional simple random sampling designs. The considered examples of empirical analysis lead to the conclusion that under some additional conditions the proposed estimation strategies based on the conditional simple random sample are usually more accurate than the mean from the simple random sample drawn without replacement.
Źródło:
Statistics in Transition new series; 2016, 17, 3; 411-428
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Przetwarzanie sygnałów próbkowanych nierównomiernie w systemach pomiarowych z częstotliwościowym nośnikiem informacji
Nonuniformly sampling signal processing in measurements systems with frequency carrier of information
Autorzy:
Pawłowski, E.
Powiązania:
https://bibliotekanauki.pl/articles/154408.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
próbkowanie nierównomierne
przetwarzanie sygnałów
nonuniform sampling
signal processing
Opis:
W referacie przedstawia się problematykę cyfrowego przetwarzania sygnałów w systemach pomiarowych z częstotliwościowym nośnikiem informacji. W przetwornikach z wyjściem częstotliwościowym w stanach dynamicznych częstotliwość chwilowa reprezentuje chwilową wartość przetwarzanej wielkości, a próbki sygnału są nierównomiernie rozmieszczone w czasie. Ten nierównomiernie próbkowany sygnał może być dalej przetwarzany po uzyskaniu próbek rozmieszczonych równomiernie poprzez zastosowanie resamplingu. Prezentowany algorytm może być zastosowany w tych wszystkich sytuacjach gdy częstotliwość sygnału niesie informację o chwilowych wartościach wielkości fizycznej przetwarzanej w systemie, np.: w badaniach ruchu obrotowego maszyn wirujących z zastosowaniem przetwornika inkrementalnego, testowaniu w stanach dynamicznych przetworników z wyjściem częstotliwościowym, w tym również generatorów sterowanych napięciowo (VCO), sprawdzaniu stabilności generatorów lub częstotliwości w sieci energetycznej i innych.
This paper presents several problems of digital signal processing in measurements systems with frequency carrier of information. In sensors of frequency output under dynamic conditions instantaneous frequency values represent instantaneous values of a processed quantity and the signal samples are irregularly distributed in time. This irregularly sampled signal can be analysed by extracting a regularly sampled signal from the irregular data with resampling. Presented algorithm can be applied in all the cases when frequency of a signal carries information about instantaneous values of a physical quantity processed in the system, for example: testing of angular motion in rotating machines with the application of an incremental encoder, testing of converters with frequency outputs in dynamic states including operation tests on oscillators controlled by voltage (VCO), stability testing of generators or frequency in power grids etc.
Źródło:
Pomiary Automatyka Kontrola; 2007, R. 53, nr 9 bis, 9 bis; 130-133
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressed sensing in MRI : mathematical preliminaries and basic examples
Autorzy:
Błaszczyk, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/146500.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
compressed sensing
magnetic resonance imaging
sampling theory
sparsity
Opis:
In magnetic resonance imaging (MRI), k-space sampling, due to physical restrictions, is very time- -consuming. It cannot be much improved using classical Nyquist-based sampling theory. Recent developments utilize the fact that MR images are sparse in some representations (i.e. wavelet coeffi cients). This new theory, created by Candès and Romberg, called compressed sensing (CS), shows that images with sparse representations can be recovered from randomly undersampled k-space data, by using nonlinear reconstruction algorithms (i.e. l1-norm minimization). Throughout this paper, mathematical preliminaries of CS are outlined, in the form introduced by Candès. We describe the main conditions for measurement matrices and recovery algorithms and present a basic example, showing that while the method really works (reducing the time of MR examination), there are some major problems that need to be taken into consideration.
Źródło:
Nukleonika; 2016, 61, 1; 41-43
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Automatic Synthesis of Musical Phrases from Multi-Pitch Samples
Autorzy:
Pluta, M.
Spalek, L. J.
Delekta, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/177577.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound synthesis
synthesis methods
sampling
Concatenative Sound Synthesis
Opis:
Sound synthesizers are a natural element of a musician’s toolset. In music arrangement, samplers can often produce satisfactory results, but it requires a combination of manual and automatic methods that may be arduous at times. Concatenative Sound Synthesis reproduces many of natural performance- and expression-related nuances but at a cost of high demand for processing power. Here, another method of musical phrase synthesis aimed at music arrangement is presented that addresses these and other related issues. Contrary to common practice, we propose to record and utilize sound samples containing not one, but short sequences of pitches. In effect, natural pitch transitions are preserved and phrases appear to be much smoother, despite using very limited set of performance rules. The proof-of-concept implementation of the proposed method is discussed in detail along with attempts at optimizing the final sound effects, based on auditory tests. The limitations and future applications of the synthesizer are also discussed.
Źródło:
Archives of Acoustics; 2017, 42, 2; 235-247
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of single gene multitrait effects in livestock by the use of Gibbs sampling
Autorzy:
Dobek, A
Molinski, K.
Szydlowski, M.
Szwaczkowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/2042024.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gene
gene frequency
major gene
livestock
Gibbs sampling
Źródło:
Journal of Applied Genetics; 2000, 41, 4; 275-283
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressed optical image encryption in the diffractive-imaging-based scheme by input plane and output plane random sampling
Autorzy:
Wan, Shujia
Gong, Qiong
Wang, Hongjuan
Ma, Shibang
Qin, Yi
Powiązania:
https://bibliotekanauki.pl/articles/2060687.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
diffractive-imaging-based encryption
compressive sensing
random sampling
Opis:
The successful recovery of the plaintext in the simplified diffractive-imaging-based encryption (S-DIBE) scheme needs to record one intact axial intensity map as the ciphertext. By aid of compressive sensing, we propose here a new image encryption approach, referred to as compressed DIBE (C-DIBE), which allows further compression of the intensity map. The plaintext is sampled before being sent to DIBE. Afterwards, the intensity map recorded by the CCD camera is also processed by such sampling operation to generate the ciphertext. For decryption, we first obtain the sparse plaintext using the proposed phase retrieval algorithm, and then reobtain the primary plaintext from it via compressive sensing. Numerical results show that a proper proportion of the intensity map (e.g. 50%) is enough to totally recover a grayscale image. We achieve multiple-image encryption by space multiplexing without enlarging the size of the ciphertext. The robustness of C-DIBE against brute-force attack evidently outperforms S-DIBE due to the extended key space. Numerical simulation has been presented to confirm the proposal.
Źródło:
Optica Applicata; 2022, 52, 1; 51--66
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Developing calibration estimators for population mean using robust measures of dispersion under stratified random sampling
Autorzy:
Audu, Ahmed
Singh, Rajesh
Khare, Supriya
Powiązania:
https://bibliotekanauki.pl/articles/1054567.pdf
Data publikacji:
2021-06-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
calibration
outliers
percentage relative efficiency (PRE)
stratified sampling
Opis:
In this paper, two modified, design-based calibration ratio-type estimators are presented. The suggested estimators were developed under stratified random sampling using information on an auxiliary variable in the form of robust statistical measures, including Gini’s mean difference, Downton’s method and probability weighted moments. The properties (biases and MSEs) of the proposed estimators are studied up to the terms of firstorder approximation by means of Taylor’s Series approximation. The theoretical results were supported by a simulation study conducted on four bivariate populations and generated using normal, chi-square, exponential and gamma populations. The results of the study indicate that the proposed calibration scheme is more precise than any of the others considered in this paper.
Źródło:
Statistics in Transition new series; 2021, 22, 2; 125-142
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena parametrów 3D wyznaczonych metodą próbkowania spiralnego
The evaluation of 3D parameters appointed using the spiral sampling method
Autorzy:
Majchrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/277341.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
próbkowanie spiralne
topografia powierzchni
spiral sampling
surface topography
Opis:
W Zakładzie Metrologii i Systemów Pomiarowych Politechniki Poznańskiej opracowano nową metodę pomiaru trójwymiarowej geometrii powierzchni bazującą na próbkowaniu spiralnym. Jest to nowe podejście do zagadnienia zbierania punktów z powierzchni za pomocą niekartezjańskiej siatki próbkowania. Pomiar wykonuje się na siatce utworzonej ze zbioru punktów tworzących spiralę Archimedesa. Główną zaletą tej metody jest mniejsza czasochłonność pomiaru w porównaniu z innymi siatkami próbkowania. Stosując siatkę prostokątną, po każdym przejściu końcówki pomiarowej należy wycofać ją w położenie początkowe. Należy także poprzecznie przesunąć stolik pomiarowy o wartość odpowiadającą odległości między kolejnymi przejściami. Jeśli przy próbkowaniu spiralnym może być mowa o odcinkach wejściowym i wyjściowym, to tylko przy rozpoczęciu i przy zakończeniu pomiaru, ponieważ końcówka przez cały czas pomiaru jest w ruchu. Jest to oczywisty zysk czasu, który może wynosić od 30 % do 70 % w porównaniu z czasem przy użyciu siatki prostokątnej. Próbkowanie spiralne rozwiązuje problem czasochłonności pomiarów przestrzennych powierzchni. Jednakże, jak pokazały badania, istnieją różnice w wartościach parametrów 3D, uzyskanych metodą próbkowania spiralnego i metodą siatki prostokątnej. Nie była również znana zależność opisująca wpływ parametrów siatki spiralnej (skok spirali) na wartości parametrów przestrzennych. W artykule przedstawiono analizę wpływu próbkowania spiralnego na parametry topografii powierzchni. Podczas badań korzystano z programów MATLAB, AWK, Statistica. Do pomiarów powierzchni wykorzystano profilometry Perthen, TOPO, Wyko. Za pomocą wymienionych narzędzi opracowano program do analizy i symulacji metody próbkowania spiralnego. Przeprowadzono badania symulacyjne strategii próbkowania spiralnego dla wytypowanych powierzchni.
In the world around us, all the surfaces are rough. Most of surfaces in mechanics are very complicated, and in order to describe it with certain values, the measurement and analysis of some parameters should be performed. Before 1980th, roughness analysis consisted of 2D measurement, which gave twodimensional characteristics of the surface. During the last decades, many scientists and constructors became convinced that the third dimension should be added to the analysis. At present, 3D analysis of the surface geometry is widely accepted, though some disorder in terminology and in 3D parameters classification is still present. One of important problems is also the way of measurement (points collection) for further analysis. Most of known measuring systems collect a number of parallel profiles. Are known also efforts to collect radial profiles from one point. Anyway, the stereometrical surface measurement requires far more time than typical 2D measurement. In the Division of Metrology of Poznan University of Technology the new method of measurement has been worked out, based on spiral sampling. One of the most important merits of this kind of measurement is much shorter time, when the surface of same dimensions is to be measured. When the parallel profiles are being collected, after each movement forward, the useless move back would come, and also the movement in perpendicular direction (step between profiles) would take additional time. Moreover, in each profile, beside the evaluation length, there are allowances for run-up and for overtravel. In spiral sampling, those allowances appear only once, at the beginning and at the end of measuring process, and the stylus collects the point during all the time of movement. Comparing to parallel profiles, the spiral sampling takes 30 % to 70 % less time of measurement.
Źródło:
Pomiary Automatyka Robotyka; 2012, 16, 6; 56-59
1427-9126
Pojawia się w:
Pomiary Automatyka Robotyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of digital transformation and MSMEs performance from a spatial perspective: Evidence from China
Autorzy:
Zheng, Bing
Yuan, Yuqing
Li, Huizhuan
Jiang, Yihan
Powiązania:
https://bibliotekanauki.pl/articles/18721474.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Ekonomiczny w Katowicach
Tematy:
digital transformation
double sampling frame
performance analysis
MSMEs
Opis:
Aim/purpose – Not only have micro, small, and medium enterprises (MSMEs) been regarded as a driving force of the national economy, but they have also become important in promoting innovation and entrepreneurship. In general, today’s MSMEs face problems, such as high business costs, insufficient innovation, and inadequate management capabilities, that have all forced the digital transformation of MSMEs. However, in existing studies, the impact of digital transformation on performance is controversial, and the subjects are generally listed companies. In this paper, we have decided to use micro business survey data and analyze them from a spatial perspective to explore how MSMEs’ digital transformation plays a role in influencing performance and the path of its effect. Design/methodology/approach – We use a sampling method with a dual directory-regional sampling frame to investigate MSMEs in Ningbo City, Zhejiang Province, China and then delve into the impact of digital transformation on enterprise performance from a spatial perspective by the spatial weighted logit model. Findings – Hierarchical analysis shows that there is a large room for improvement in the Digital transformation of enterprises. The digitalization level of an enterprise has a positive impact on performance. While from a spatial perspective, the digitalization level of neighboring enterprises has a negative impact on the performance of the enterprise. Path analysis shows that the digital transformation of enterprises can increase innovation, reduce costs, and improve the performance of enterprises. Originality/value – We provide an empirical basis for vigorously promoting the digital transformation of enterprises, jointly building digital parks, and improving enterprise performance by reducing costs and improving efficiency. At the same time, it provides relevant suggestions for digital transformation for manufacturing MSMEs that are hesitant to see or are at a loss in the digital transformation and helps manufacturing MSMEs to achieve cost reduction and increase efficiency.
Źródło:
Journal of Economics and Management; 2023, 45; 319-343
1732-1948
Pojawia się w:
Journal of Economics and Management
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probability vs. Nonprobability Sampling: From the Birth of Survey Sampling to the Present Day
Autorzy:
Kalton, Graham
Powiązania:
https://bibliotekanauki.pl/articles/18105097.pdf
Data publikacji:
2023-06-13
Wydawca:
Główny Urząd Statystyczny
Tematy:
Anders Kiaer
Jerzy Neyman
representative sampling
quota sampling
hard-to-survey populations
model-dependent inference
internet surveys
big data
administrative records
Opis:
At the beginning of the 20th century, there was an active debate about random selection of units versus purposive selection of groups of units for survey samples. Neyman's (1934) paper tilted the balance strongly towards varieties of probability sampling combined with design-based inference, and most national statistical offices have adopted this method for their major surveys. However, nonprobability sampling has remained in widespread use in many areas of application, and over time there have been challenges to the Neyman paradigm. In recent years, the balance has tilted towards greater use of nonprobability sampling for several reasons, including: the growing imperfections and costs in applying probability sample designs; the emergence of the internet and other sources for obtaining survey data from very large samples at low cost and at high speed; and the current ability to apply advanced methods for calibrating nonprobability samples to conform to external population controls. This paper presents an overview of the history of the use of probability and nonprobability sampling from the birth of survey sampling at the time of A. N. Kiaer (1895) to the present day.
Źródło:
Statistics in Transition new series; 2023, 24, 3; 1-22
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple proof of incorrectness of the formula describing aliasing and folding effects in spectrum of sampled signal in case of Ideal signal sampling
Autorzy:
Borys, A.
Powiązania:
https://bibliotekanauki.pl/articles/2063994.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
folding effects
ideal signal sampling
incorrectness of the Formula
aliasing effects
spectrum of a sampled signal
signal sampling
proof of incorrectness
Opis:
A simple proof of the incorrectness of the formula, which is used in the literature nowadays, for description of the aliasing and folding effects in the spectrum of a sampled signal in the case of an ideal signal sampling, is given in this paper. By the way, it is also shown that such the effects cannot occur at all, when the signal sampling is considered to be performed perfectly.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2021, 15, 3; 873--876
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pomiar strumienia płynu w rurociągu za pomocą przepływomierza próbkujacego z punktowym pomiarem predkości
Flow-rate measurement in the pipeline with help of sampling flowmeter with point velocity measurement
Autorzy:
Waluś, S.
Powiązania:
https://bibliotekanauki.pl/articles/152472.pdf
Data publikacji:
2008
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
pomiar strumienia płynu
przepływomierz próbkujący
pomiar prędkości płynu
flow-rate measurement
sampling flowmeter
optimization of sampling flowmeter
fluid velocity measurement
Opis:
W pracy zdefiniowano przepływomierz próbkujący i porównano go z przepływomierzem całoprzewodowym. Do modelowania rozkładu prędkości w rurociagu użyto wzoru Prandtla i uniwersalnego. Przedstawiono pięć sposobów umiejscowienia czujnika prędkości punktowej w powierzchni rurociagu: w osi, w miejscu przełomowym, w miejscu równopowierzchniowym, w miejscu równostrumieniowym i w miejscu optymalnym. Dla położenia optymalnego sformułowano dwie funkcje celu i dla konkretnego przypadku wyznaczono położenia czujnika. Przedstawiono metodę obliczania wielkości mierzonej, to jest strumienia objętości.
In the paper sampling tlowmeters are defined and compared with full-bore flowmeters. For modeling of velocity distribution in the pipeline Prandtl and universal formulae are introduced. Five arts of velocity sensor positions are introduced: centerline position - in the pipe axis, critical position - point velocity is equal to average velocity, equal surface position, equal flow-rate position and optimal position. For optimal position are proposed two objective functions. One concrete example of optimization is introduced - minimizing relative and absolute error. Calculations shows, that the sensor positions for these two objective functions are different. The method of reproducing measurand (volumetric flow-rate) in sampling flowmeter is given.
Źródło:
Pomiary Automatyka Kontrola; 2008, R. 54, nr 5, 5; 286-289
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Endometrial histopathology, bacteriology and cytology outcomes in mares with early embryonic death (EED): a field study
Autorzy:
Długołęcka, E.
Tobolski, D.
Janowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/2087526.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
equine
uterine biopsy
early embryonic loss
pregnancy
sampling methods
Źródło:
Polish Journal of Veterinary Sciences; 2019, 2; 377-384
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sampling, metadata and DNA extraction - important steps in metagenomic studies
Autorzy:
Felczykowska, Agnieszka
Krajewska, Anna
Zielińska, Sylwia
Łoś, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/1039153.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
sampling
DNA extraction
DNA purification
soil
water
wastewater
metadata
Opis:
Metagenomic studies have become increasingly popular. They allow for the estimation of biodiversity in complex populations. This diversity presents an enormous but largely unexpected genetic and biological pool and can be exploited for the recovery of novel genes, entire metabolic pathways and their products. Generally metagenomic study is a genomic analysis of organisms by direct extraction and cloning of DNA from their natural environment. The most common problems of modern metagenomics are as follows: majority of the microorganisms present in the environment cannot be cultivated by standard techniques, DNA extraction methods are not very effective, isolated DNA is contaminated with various compounds, a choice for a screening method is not obvious.
Źródło:
Acta Biochimica Polonica; 2015, 62, 1; 151-160
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Derivation of Discrete Time Fourier Transform from Its Continuous Counterpart
Autorzy:
Borys, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/227150.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sampling of signals
discrete time
continuous time
Fourier transforms
Opis:
This paper is devoted to some problems that appear in derivations of the discrete time Fourier transform from a formula for its continuous time counterpart for transformation from the time into the frequency domain as well as to those regarding transformation in the inverse direction. In particular, the latter ones remained so far an unresolved problem. It is solved for the first time here. Many detailed explanations accompanying the solution found are presented. Finally, it is also worth noting that our derivations do not exploit any of such sophisticated mathematical tools as the so-called Dirac delta and Dirac comb.
Źródło:
International Journal of Electronics and Telecommunications; 2020, 66, 2; 355-360
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cytaty i plagiaty. Tekst piosenki i wypowiedzi slamerskie w świetle prawa autorskiego
Quotes and Plagiarisms. Songs and Slam Poetry Texts Under the Copyright Law. Comparative Perspective
Autorzy:
Świerkowska, Dagmara
Powiązania:
https://bibliotekanauki.pl/articles/1787898.pdf
Data publikacji:
2021-09-30
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
slam poetry
songs lyrics
copyright
mash-up
sampling
plagiarism
Opis:
The most important function of copyright is the protection of products of creativity, property rights and personal creator. In this broad sense, the laws protecting the author are understood and accepted by practice all over the world. The main focus of this article is to analyse the lyrics of Polish songs whose authors entered the judicial path to investigate one’s rights, and to compare them with spoken word texts, which, due to frequent references to the works of other authors, could be considered illegal. The research material consists of open court judgments, song lyrics and recordings of slam poetry texts collected by the author.
Źródło:
Poznańskie Studia Polonistyczne. Seria Językoznawcza; 2021, 28, 1; 171-188
1233-8672
2450-4939
Pojawia się w:
Poznańskie Studia Polonistyczne. Seria Językoznawcza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The granular computing implementation for road traffic video-detector sampling rate finding
Zastosowanie teorii obliczeń ziarnistych do wyznaczania czasu próbkowania wideo-detektora pojazdów
Autorzy:
Płaczek, B.
Powiązania:
https://bibliotekanauki.pl/articles/375387.pdf
Data publikacji:
2009
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
wideodetektor
ruch drogowy
próbkowanie
video detector
sampling
road traffic
Opis:
The method discussed in this contribution allows to estimate the necessary data granularity for an on-line traffic controlling, using the information recorded by digital video-camera. Due to define the data sampling rate modelling and analysis methods were applied. They are used for extracting prediction rules of the traffic descriptors. The discussed scheme combines granular computing algorithms with assumptions of a cellular automata traffic model. It enables direct determination of temporal characteristics for the recognised and extracted traffic states. The traffic parameters prediction algorithm was introduced that allow determining the sampling time intervals of the video detection system
Metoda przedstawiona w niniejszym artykule pozwala na oszacowanie poziomu ziarnistości danych niezbędnego do sterowania on-line ruchem drogowym na podstawie informacji obrazowej rejestrowanej kamerą wideo. W celu zdefiniowania czasu próbkowania danych zastosowano metody modelowania i analizy, które pozwalają na wydobycie reguł predykcji dla deskryptorów ruchu drogowego. Prezentowana metoda stanowi połączenie algorytmów granulacji danych z założeniami komórkowego modelu ruchu. Metoda ta umożliwia bezpośrednie określenie charakterystyk czasowych na podstawie rozpoznanych stanów ruchu pojazdów. Zaproponowano algorytm predykcji parametrów ruchu drogowego, który pozwala wyznaczyć przedziały czasu próbkowania dla systemu wideo-detekcji.
Źródło:
Transport Problems; 2009, 4, 1; 55-62
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Losowanie zrównoważone i kalibracja
A balanced sampling and calibration
Сбалансированная выборка и калибровка
Autorzy:
Kozłowski, Arkadiusz
Powiązania:
https://bibliotekanauki.pl/articles/542548.pdf
Data publikacji:
2016-03
Wydawca:
Główny Urząd Statystyczny
Tematy:
losowanie zrównoważone
kalibracja
balanced sampling
calibration
сбалансированная выборка
калибровка
Opis:
Losowanie zrównoważone polega na takim doborze próby, aby szacunki sum zmiennych pomocniczych estymatorem Horvitza-Thompsona równały się rzeczywistym sumom tych zmiennych. Kalibracja natomiast polega na modyfikacji wyjściowych wag wynikających z planu losowania w taki sposób, aby zmodyfikowane wagi odtwarzały znane sumy zmiennych pomocniczych. Ideą obu metod jest odwzorowanie wartości globalnych zmiennych dodatkowych. Celem artykułu jest przedstawienie i porównanie obu technik traktowanych jako alternatywa do osiągnięcia tego samego celu. Więcej uwagi poświęcono losowaniu zrównoważonemu. Algorytm doboru próby zilustrowano za pomocą dwóch prostych przykładów. Porównanie losowania zrównoważonego z kalibracją wypada korzystniej dla tej drugiej metody, jednak najlepszym rozwiązaniem jest zastosowanie obu metod jednocześnie.
A balanced sampling design is a design in which Horvitz-Thompson estimators of population totals for a set of auxiliary variables equal the known totals of these variables. On the other hand, calibration is a technique where the modification of design weights occurs in such a way that the new weights, when applied to auxiliary variables, reproduce, i.e. estimate without error, the known totals for these variables. The general idea behind balanced sampling and calibration is thus the same — both techniques tend to reproduce known totals of the auxiliary variables. The purpose of the paper is to describe and compare both techniques, considering them as alternatives in achieving the same goal. More attention was devoted to balanced sampling. The algorithm for selecting a sample was illustrated with two numerical examples. The comparison between balanced sampling and calibration, as alternatives, indicates calibration, but the best strategy is to use both methods simultaneously.
Сбалансированная выборка заключается в такой выборке, чтобы оценки вспомогательных сумм величин оценкой Хорвица-Томсона были равны фактическим суммам этих величин. В то же время калибровка состит в модификации выходных весов являющихся результатом плана выборки так, чтобы модифицированные весы воссоздавали известные суммы вспомогательных величин. Идея обоих методов состоит в копировании значения глобальных дополнительных величин. Целью статьи является представление и сопоставление двух методов, которые считаются альтернативой для достижения той же цели. Больше внимание было уделено сбалансированной выборке. Алгоритм выборки представлен с помощью двух простых примеров. Сравнение сбалансированной выборки с калибровкой является выгодным для другого метода, но самым хорошим решением является одновременное использование обоих методов.
Źródło:
Wiadomości Statystyczne. The Polish Statistician; 2016, 3; 38-60
0043-518X
Pojawia się w:
Wiadomości Statystyczne. The Polish Statistician
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Best Linear Unbiased Estimators of Population Mean on Current Occasion in Two-Occasion Rotation Patterns
Autorzy:
Singh, G. N.
Prasad, S.
Powiązania:
https://bibliotekanauki.pl/articles/465782.pdf
Data publikacji:
2013
Wydawca:
Główny Urząd Statystyczny
Tematy:
successive sampling
auxiliary information
unbiased
variance
optimum replacement policy
Opis:
Best linear unbiased estimators have been proposed to estimate the population mean on current occasion in two-occasion successive (rotation) sampling. Behavior of the proposed estimators have been studied and their respective optimum replacement policies are discussed. Empirical studies are carried out to examine the performance of the proposed estimators and consequently the suitable recommendations are made.
Źródło:
Statistics in Transition new series; 2013, 14, 1; 57-74
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation tests on errors of the measuring path with a frequency carrier of information
Symulacyjne badania błędów toru pomiarowego z częstotliwościowym nośnikiem informacji
Autorzy:
Pawłowski, E.
Powiązania:
https://bibliotekanauki.pl/articles/157165.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
instantaneous frequency
nonuniformly sampling
resampling
częstotliwość chwilowa
próbkowanie nierównomierne
Opis:
The paper presents a problem concerning digital processing of signals in measuring systems with sensors of pulse frequency output. Under dynamic conditions instantaneous frequency values represent instantaneous values of a processed quantity and the signal samples are irregularly distributed in time. Moreover, the time between samples may depend on the current and previously values of the processed quantity. Such an irregularly sampled signal can be further analyzed with the application of resampling to extract a regularly sampled signal from the irregular data. The difference between the estimated and the true signal is analyzed as a measuring error.
W pracy rozpatrzono zagadnienie cyfrowego przetwarzania sygnału w torze pomiarowym z czujnikiem posiadającym impulsowe wyjście częstotliwościowe. W stanie statycznym częstotliwość impulsów na wyjściu takiego czujnika jest proporcjonalna do wartości wielkości przetwarzanej w torze pomiarowym. Niezmienną w czasie częstotliwość można wieloma znanymi sposobami przetworzyć na wartość cyfrową ze stosunkowo wysoką dokładnością. W rozdziale 2 przedstawiono problem analizy pracy rozważanego toru pomiarowego w stanach dynamicznych, gdy chwilowe wartości częstotliwości impulsowego sygnału reprezentują chwilowe wartości przetwarzanej wielkości. Ponieważ dla sygnału impulsowego nie jest możliwe wyznaczenie przyrostów fazy mniejszych od jednego okresu, w praktyce nie można również wyznaczyć jego częstotliwości chwilowej. Próbki sygnału częstotliwościowego mogą być wyznaczone nie częściej niż co kolejny jego okres i reprezentują one wartości średnie wielkości wejściowej w tym okresie. Dodatkowym utrudnieniem jest nierównomierne rozmieszczenie tych próbek w czasie. W rozdziale 3 przedstawiono algorytm przetwarzania sygnału częstotliwościowego w celu uzyskania próbek rozmieszczonych równomiernie w czasie, a w rozdziale 4 omówiono metodę symulacyjnego badania błędów w rozpatrywanym torze pomiarowym. Błędy zdefiniowano jako różnicę pomiędzy odtworzonymi wartościami chwilowymi sygnału i wartościami sygnału podanego w postaci analitycznej na wejście algorytmu symulacyjnego. Wyznaczano wartości chwilowe i średniokwadratowe błędów. W rozdziale 5 przedstawiono uzyskane przykładowe wartości błędów kwantowania i uśredniania oraz błędów równomiernego resamplingu, w zależności od parametrów przetwarzanej wielkości: jej częstotliwości oraz stosunku składowej stałej do składowej przemiennej.
Źródło:
Pomiary Automatyka Kontrola; 2014, R. 60, nr 8, 8; 607-609
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prawo Benforda w rewizji finansowej
Benfords law in auditing
Autorzy:
Jeremicz, Patryk
Powiązania:
https://bibliotekanauki.pl/articles/2041299.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Ekonomiczny w Katowicach
Tematy:
Audyt
Prawo Benforda
Próbkowanie
Audit
Benford’s law
Sampling
Opis:
Najczęściej stosowane metody doboru próby w celu zebrania dowodów księgowych i przeprowadzenia badania ksiąg rachunkowych są oparte na rachunku prawdopodobieństwa. Wyróżnić można próbkowanie proste, monetarne oraz warstwowe. Biorąc pod uwagę tylko kryterium losowości, można również dodać technikę opartą na wyborze losowym. W celu zminimalizowania subiektywności w ocenie poszczególnych segmentów sprawozdania finansowego badacz może poszerzyć spektrum swoich obserwacji o analizę zmian poszczególnych kategorii. Dodatkowo istnieje metoda pozwalająca porównać rozkład częstości występowania danej cyfry w sprawozdaniu z rozkładem, który występuje naturalnie, a jest zwany rozkładem Benforda. Stosowanie prawa cyfr pierwszych jest mniej popularne od metod bazujących na rachunku prawdopodobieństwa. Wynika to m.in. z faktu, iż prawo Benforda wymaga wielu obliczeń i pozwala wyznaczyć jedynie pewne grupy operacji, które powinny być zbadane. W niniejszym artykule zostaną zaprezentowane pewne metody pozwalające wdrożyć to prawo w badaniu ksiąg rachunkowych.
The most common sampling methods used to gather audit evidence are based on probability. Sampling can be distinguished: simple, monetary and stratified. Considering only the randomness criterion, one can also add a technique based on random selection. In order to minimize the subjectivity in assessing particular segments of the financial statements, an investigator may extend the observations to include an analysis of changes in individual categories. Additionally, there is a method that allows you to compare the frequency distribution of a given digit in the report with the distribution that occurs naturally, called the Benford distribution. The application of the law of prime numbers is less popular than the methods based on probability theory. This is due, inter alia, to the fact that Benford's law requires many calculations and allows to designate only certain groups of operations that should be examined. In this article some methods will be presented to implement this law in auditing the books of accounts.
Źródło:
Studia Ekonomiczne; 2020, 394; 19-38
2083-8611
Pojawia się w:
Studia Ekonomiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Attention-based U-Net for image demoiréing
Autorzy:
Lehmann, Tomasz M.
Powiązania:
https://bibliotekanauki.pl/articles/2201228.pdf
Data publikacji:
2022
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Instytut Informatyki Technicznej
Tematy:
image demoiréing
computer vision
attention U-Net
cross-sampling
Opis:
Image demoiréing is a particular example of a picture restoration problem. Moiré is an interference pattern generated by overlaying similar but slightly offset templates. In this paper, we present a deep learning based algorithm to reduce moiré disruptions. The proposed solution contains an explanation of the cross-sampling procedure - the training dataset management method which was optimized according to limited computing resources. Suggested neural network architecture is based on Attention U-Net structure. It is an exceptionally effective model which was not proposed before in image demoiréing systems. The greatest improvement of this model in comparison to U-Net network is the implementation of attention gates. These additional computing operations make the algorithm more focused on target structures. We also examined three MSE and SSIM based loss functions. The SSIM index is used to predict the perceived quality of digital images and videos. A similar approach was applied in various computer vision areas. The author’s main contributions to the image demoiréing problem contain the use of the novel architecture for this task, innovative two-part loss function, and the untypical use of the cross-sampling training procedure.
Źródło:
Machine Graphics & Vision; 2022, 31, 1/4; 3--17
1230-0535
2720-250X
Pojawia się w:
Machine Graphics & Vision
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Macroelements: zinc and iron in well water in the Upper Narew River catchment
Makroelementy, cynk i zelazo w wodach studziennych doliny Gornej Narwi
Autorzy:
Skorbilowicz, M
Skorbilowicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/15849.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Tematy:
Upper Narew River
Narew catchment
potassium
well water sampling
well water sampling site
shallow ground water
macroelement
zinc
well water
iron
Opis:
The aim of the present study was to evaluate the spatial distribution of concentrations of some elements in shallow ground waters as well as to find the main sources of their origin. The investigations were carried out in 8 villages in Podlasie region. The water sampling sites were in the villages Sobótka, Narew, Ciełuszki, Kaniuki, Zawyki, Uhowo, Topilec, and Złotoria, all on or near the Narew River. Water samples were collected in spring, summer, and autumn of 2006. The samples underwent determinations of calcium, magnesium, sodium, potassium, zinc, and iron concentrations by means of AAS and EAS techniques after previous filtering through micro-pore filters (d=0.45 pm). None of the tested water samples met the standards for potable water specified in the Decree of the Ministry for Health of 2007 as they exceeded permissible concentrations of iron ions. Regarding potassium ions, the well waters were classified to underground waters quality class V. The waters with the highest values of the tested parameters were found in wells in Kaniuki, Złotoria and Zawyki.
Celem pracy było określenie rozkładu przestrzennego stężenia wybranych składników płytkich wód podziemnych oraz określenie głównych czynników ich pochodzenia. Badania przeprowadzono w 8 wsiach położonych w województwie podlaskim. Miejsca poboru próbek wody wyznaczono w miejscowościach: Sobótka, Narew, Ciełuszki, Kaniuki, Zawyki, Uhowo, Topilec, Złotoria, zlokalizowanych wzdłuż rzeki Narew w jej bezpośrednim sąsiedztwie. Próbki wody pobierano w terminach: wiosna, lato, jesień 2006 r. W próbkach oznaczono stężenie jonów wapnia, magnezu, sodu, potasu, cynku i żelaza metodą AAS i ESA po ich przefiltrowaniu przez filtry mikroporowate o średnicy porów 0,45 pm. Badane wody nie odpowiadały standardom wody przeznaczonej do spożycia określonym w Rozporządzeniu Ministra Zdrowia z 2007 r., z powodu przekroczenia wartości dopuszczalnych stężenia jonów żelaza. Ze względu na stężenie jonów potasu wody badanych studni zakwalifikowano do V klasy jakości wód podziemnych. Wody o najwyższych wartościach stężenia badanych parametrów stwierdzono w studniach zlokalizowanych we wsiach Kaniuki, Złotoria i Zawyki.
Źródło:
Journal of Elementology; 2008, 13, 1
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of pressure behavior in a temperature controlled molecular dynamic flow
Autorzy:
Najafi, H. R.
Karimian, S. M. H.
Powiązania:
https://bibliotekanauki.pl/articles/280901.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nanofluid
molecular dynamics
pressure
bin size
sampling
periodic flow
Opis:
Thermo-fluid properties are required for numerical modeling of nano/micro devices. These properties are mostly obtained from results of molecular dynamics (MD) simulations. Therefore, efforts have been put in developing methods for numerical evaluation of fluid properties, such as pressure. In this paper, the pressure behavior in a controllable nanochannel flow is investigated. The nanoflow field is created by imposing a gradient of a macroscopic property such as temperature. Details of the pressure calculation method in a molecular system and its sensitivity to the approximations made are described first. The effect of temperature rise in a uniform flow on the pressure field is studied next. Then, in the flow under a fixed mean velocity condition, the effect of temperature gradient as a controllable property on the pressure field of nanoflow is studied. Velocity, pressure and molecular density of nanoflows with various temperature gradients and different temperature levels are investigated as well. It has been found that the temperature level at which the temperature gradient is imposed, is important. A fixed temperature gradient will not always lead to the same pressure gradient at different temperature levels. Furthermore, quite interestingly, it is observed that at a fixed temperature gradient, with the variation of mean velocity the pressure field also varies.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 881-892
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Określenie próby i jej liczności w badaniach pedagogicznych
Definition of the sample and its size in pedagogical research
Autorzy:
Matuszak, Alla
Matuszak, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/443077.pdf
Data publikacji:
2011
Wydawca:
ADVSEO
Tematy:
SAMPLE SIZE
SAMPLING
DRAWING SAMPLE
DRAWING SAMPLE FROM STRATA
Opis:
In the statistical analysis it is sometimes necessary to determine sample size. It is not required if the results are not collected by means of statistical apparatus, and it serves only to present the observed phenomena or mileages. In the presented material some ways to determine sample size and sampling are given. Sampling from unknown and known set, drawing sample from strata, as well as multistage sample, systematic and in beams is characterized. Also comments on the costs of sampling and the proportions in the sample are presented.
Źródło:
General and Professional Education; 2011, 2; 33-39
2084-1469
Pojawia się w:
General and Professional Education
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Maximization of Estimation Accuracy in Multiparameter Two Stage Sampling
O maksymalizacji dokładności estymacji w wieloparametrowym losowaniu dwustopniowym
Autorzy:
Skibicki, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/904926.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
two stage sampling
sample allocation
covariance matrix
spectral radius
Opis:
In the paper the problem of sample allocation for both stages in such a way, that the accuracy of an estimation of the means of many variables is maximal and the survey cost is restricted is considered. As the measure of accuracy, value of the spectral radius of covariance matrix of means estimators vector is taken. It was proved that the spectral radius is a convex function of sample sizes. That allows effective solving the problem using known methods adapted to this issue.
W pracy rozważano zadanie ustalenia liczebności prób losowanych na obydwu stopniach losowania tak, aby dokładność estymacji średnich wielu cech populacji była maksymalna przy kosztach obserwacji próby nieprzekraczających zadanego poziomu. Za miarę dokładności estymacji przyjęto wartość promienia spektralnego macierzy kowariancji wektora estymatorów wartości średnich cech. Wykazano, że promień spektralny tej macierzy dla przekształconego zadania jego minimalizacji jest wypukłą funkcją odpowiedniego wektora. Pozwala to na efektywne poszukiwanie optymalnego rozwiązania przy użyciu znanych metod adaptowanych do tego problemu.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2004, 175
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of Wearable EEG Device for Seizures Early Detection
Autorzy:
Gaidar, Viktoriia
Sudakov, Oleksandr
Powiązania:
https://bibliotekanauki.pl/articles/1844635.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
circuit design
statistical sampling
Hilbert-Huang transform
feature selection
Opis:
This paper presents the design of a wearable electroencephalography device and signal processing algorithm for early detection and forecasting of the epileptiform activity. The availability of the examination of functional brain activity for a prolonged period, outside of the hospital facilities, can provide new advantages in early diagnosis and intervention systems. In this study, the low-cost five-channel device is presented. The system consists of two main parts: the data acquisition and transmission units and processing algorithms. In order to create the robust epileptiform pattern recognition approach the application of statistical sampling and signal processing techniques are performed. The discrete wavelet and Hilbert-Huang transforms with principal component analysis are used in order to extract and select a low-dimension feature vector.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 2; 187-192
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sample allocation decisions for program evaluation: a case of multiplicative effect on units due to the developmental initiatives carried out in a phased manner
Autorzy:
Pandey, R.
Powiązania:
https://bibliotekanauki.pl/articles/38469.pdf
Data publikacji:
2010
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
developmental initiative
stratified sampling
temporal impact
sample allocation
weight
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2010, 52, 2
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of benzene, toluene, ethylbenzene and xylene in field and laboratory by means of cold fiber SPME equipped with thermoelectric cooler and GC/FID method
Autorzy:
Tajik, L.
Bahrami, A.
Ghiasvand, A.
Shahna, F. G.
Powiązania:
https://bibliotekanauki.pl/articles/779634.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
aromatic hydrocarbons
air sampling
cold fiber
solid-phase microextraction
Opis:
A simple and effective cooling device based on a thermoelectric cooler was applied to cool the SPME fiber. The device was used for quantitative extraction of aromatic hydrocarbons in the air. Several factors such as coating temperature, extraction temperature and relative humidity in the laboratory setting were optimized. Comparison of the results between the cold fiber SPME (CF-SPME) and NIOSH 1501 method on standard test atmosphere indicated a satisfactory agreement. The CF-SPME and SPME method were also compared. The results revealed that CF-SPME has the most appropriate outcome for the extraction of aromatic hydrocarbons from the ambient air. The cold fiber SPME technique showed good results for several validation parameters. Under the optimized conditions, the limits of detection (LOD) and the limits of quantification (LOQ) ranged from 0.00019 to 0.00033 and 0.0006 to 0.001 ng ml−1 , respectively. The intra-day relative standard deviation (RSD) showed ranging from 4.8 to 10.5%.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 3; 9-15
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Sampling Spacing on the Accuracy of Volume of a Medium-Size Gully
Autorzy:
Jun, Luo
Bin, Zhang
Du, Zhengpin
Zheng, Jilin
Liu, Hui
Qin, Fachao
Deng, Qinchun
Powiązania:
https://bibliotekanauki.pl/articles/123269.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
three modes
sampling spacing
gully volume
gully cross-section
Opis:
Accurate morphological parameters are key to understand the process and mechanism of gully erosion, but little information exists regarding the accuracy of gully volume influenced by sampling spacing. In order to assess the influence of sampling spacing on volume of medium gully under the condition of different shapes of gully cross-sections, as well as to provide information for proposed surveys, a MultiStation was utilized to obtain the point cloud of a Uand V-shaped gully. The coordinates were subsequently rarefied to a certain sampling spacing, and the gully volumes of three modes (Mode 1 only including rarefied terrain points; Mode 2 including detailed terrain and rarefied terrain points; Mode 3 including the rarefied detailed terrain points and terrain points with a given sampling spacing) were calculated in ArcGIS. The results showed that the error of gully volume increased non-monotonously with sampling spacing increased, and that the detail points had greater influence on the gully volume of a U-shaped than a V-shaped gully. As to Mode 1 and 2, the relative error (RE) of U-shaped gully volume increased faster with sampling spacing increasing, and presented high positive correlation. However, in the case of a V-shaped gully, a middle positive correlation for Mode 1 can be observed, and the RE was below 3% for Mode 2. For Mode 3, an increase in the sampling spacing of the terrain led to the larger RE, average RE, and variance of absolute error. If extremely high accuracy (2.5% of RE) is required, sampling spacing is less than 0.5 m; if high accuracy (5% of RE) is set, the sampling spacing of terrain points is below 0.8 m for a U-shaped gully, while the corresponding sampling spacing of terrain points and detail points are 2.0 m and 1.85 m, 3.0 m and 1.80 m, and 4.0 m and 0.75 m for a V-shaped gully. The shape of the gully’s cross-section, as well as the exact location of the shoulder line will affect the accuracy of the gully’s volume. This study will increase the efficiency of detail survey in the field for medium gully.
Źródło:
Journal of Ecological Engineering; 2019, 20, 11; 109-121
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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