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Tytuł:
Optymizm a prawidłowości percepcyjne przy ważeniu prawdopodobieństwa
Optimism/Pesimism and the Probability Weighting Function
Autorzy:
Sokołowska, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/468708.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Filozofii i Socjologii PAN
Tematy:
optimistic predictions
probability weighting function
configural weighting
dispositional optimism
Opis:
The main question of the presented experiments has been whether the probability weighting function (Kahneman, Tversky, 1979) and configural weighting incorporated in the CPT model (Tversky & Kahneman, 1992) can account for the overweighting of positive outcomes and underweigthing of negative outcomes, the phenomena first observed in the 50−ties (Irwin, 1953; Marks, 1951; – Marks-Irwin effect) and called unrealistic optimism in the current literature. In Experiment 1, carried out with 133 students, the relations between expectations of success, weights attributed to positive and 0 outcomes and the objective frequency of such outcomes were investigated in a skill situation, i. e. a competition for the best student paper. It was found that: (1) expectations of success depended strongly on the objective frequency of prizes, (2) the best outcomes were weighted in agreement with predictions of the CPT model, but (3) the same was not true for the worst outcome, i. e. 0. The results, however, could not be easily generalised because the situation was constructed such that no negative outcomes were present and 0 outcome was always the most probable. To extend studies to lotteries with negative outcomes and wider range of probabilities an additional experiment was carried out. In Experiment 2 284 students made choices between 10 pairs of 5-outcome mixed lotteries. These lotteries were constructed such the absolute utilities (calculated from CPT) of positive and negative outcomes were equal, and positive and negative outcomes had the same probabilities of occurrence. According to CPT, such lotteries should be always rejected. because negative outcomes are weighted more heavily, yielding negative overall CPT values of the lotteries. The results, however, did not support such predictions – the acceptance rate was close to 1/ . In general, the binominal distribution of acceptance of gambles with negative CPT values might suggest that some people assign optimistic weights to outcomes, i. e. overweight probabilities of positive outcomes and underweight probabilities of negative outcomes. In particular, individual differences in dispositional optimism (measured with the LOT scale) can reinforce such tendency.
Źródło:
Prakseologia; 2006, 146; 65-88
0079-4872
Pojawia się w:
Prakseologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study and Assessment of Low Frequency Noise in Occupational Settings
Autorzy:
Shehap, A. M.
Shawky, H. A.
El-Basheer, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/177844.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low frequency noise
A-weighting
C-weighting
audible
method of assessment
Opis:
Low frequency noise is one of the most harmful factors occurring in human working and living environment. Low frequency noise components from 20 to 250 Hz are often the cause of employee complaints. Noise from power stations is an actual problem for large cities, including Cairo. The noise from equipments of station could be a serious problem for station and for environmental area. The development of power stations in Cairo leads to appearing a wide range of gas turbines which are strong source of noise. Two measurement techniques using C-weighted along side the A-weighted scale are explored. C-weighting is far more sensitive to detect low frequency sound. Spectrum analysis in the low frequency range is done in order to identify a significant tonal component. Field studies were supported by a questionnaire to determine whether sociological or other factors might influence the results by using annoyance rating mean value. Subjects included in the study were 153 (mean = 36.86, SD = 8.49) male employees at the three electrical power stations. The (C-A) level difference is an appropriate metric for indicating a potential low frequency noise problem. A-weighting characteristics seem to be able to predict quite accurately annoyance experienced from LFN at workplaces. The aim of the present study is to find simple and reliable method for assessing low frequency noise in occupational environment to prevent its effects on work performance for the workers. The proposed method has to be compared with European methods.
Źródło:
Archives of Acoustics; 2016, 41, 1; 151-160
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Some Composite Estimator of the Population Mean
O pewnym estymatorze złożonym średniej w populacji
Autorzy:
Gamrot, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/907039.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
nonresponse
regression
weighting adjustment
Opis:
In this paper an estimator of the finite population mean in the unit nonresponse situation is proposed. It is constructed as a combination of the well-known regression estimator derived from the linear model and a reweighting-type estimator based on a logistic regression model. Combination weights depend on goodness of fit of respective models. Hence, the estimator for which the corresponding model better describes observed sample data dominates in the combination. Some Monte Carlo simulation results revealing its properties are presented.
W artykule zaproponowano estymator złożony średniej w populacji skończonej przy brakach odpowiedzi. Jest on kombinacją estymatora regresyjnego opartego na modelu liniowym i estymatora wykorzystującego ważenie danych opartego na modelu logistycznym. Wagi kombinacji uzależniono od miar dobroci dopasowania tych modeli do danych. Przedstawiono wyniki symulacji wykonanych dla zbadania jego własności.
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:
Simultaneous interpretive structural modelling and weighting (SISMW)
Autorzy:
Nasrollahi, Mahdi
Ramezani, Javaneh
Sadraei, Mahmoud
Fathi, Mohammad Reza
Powiązania:
https://bibliotekanauki.pl/articles/2175834.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
SISMW
MCDM
criteria
modelling
weighting
Opis:
Multi-criteria decision-making (MCDM) methods have been implemented in many fields. In the meantime, several methods have been proposed to obtain the weight of the criteria determined by various methods in different ways. In this paper, a new approach, called simultaneous interpretive structural modelling and weighting (SISMW), is proposed to solve a multi-criterion decision-making (MCDM) problem. Using SISMW, the weight of the criteria and the relationship between them could be determined simultaneously. In this approach, like the ISM method, pair comparison between criteria was made by the decision-maker to determine the relationships among the different criteria. With the help of this data, the weight of the criteria, as well as the causal (cause and effect) relationships between them, were determined in 12 steps. The main advantage of this method is that only one stage of data collection is required for obtaining weights and modelling, and so the research process may be faster. This may increase the reliability of the collected data because, in a one-step survey, the impact of time is minimized. This process can be useful for conceptualizing and developing theories to help decisionmakers understand the problem better.
Źródło:
Operations Research and Decisions; 2022, 32, 1; 111--126
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weighting of new starch-polymer salted mud with PT-23 polymer
Autorzy:
Wysocki, S.
Bielewicz, D.
Wysocka, M.
Lewicki, D.
Wilaszek, J.
Powiązania:
https://bibliotekanauki.pl/articles/298703.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
drilling muds
weighting materials
starch mud
Opis:
Rheological properties of mud should assure high rate of penetration and supply maximal hydraulic power to the hole bottom. From this point of view drilling mud should have as little density and viscosity as possible and also minimal solid phase fraction. By the reason of the hole depth and geological conditions in the region it often occurs that maintenance of low density is impossible and drilling mud have to be treated with weighting materials. The process may cause change of mud rheological parameters and cause decrease of penetration rate. In case of weighted mud there is also a problem consisting in sedimentation of weighting material. During these project realization there was developed recipe of new mud for well completion with new PT-23 polymer. The next step was testing of possibilities of weighting the mud with different weighting materials: barite with grain size lower than 75 um, barite with grain size lower than 25 um, commercial barite, hematite, bridging agent M-25. Barite with grain size lower than 75 um and barite with grain size lower than 25 um were conditioned in water, then wet separated into fractions.
Źródło:
AGH Drilling, Oil, Gas; 2014, 31, 1; 157-165
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New efficient approximation of weighting functions for simulations of unsteady friction losses in liquid pipe flow
Nowe efektywne funkcje wagowe umożliwiające symulację niestacjonarnych oporów hydraulicznych podczas przepływówniestacjonarnych oporów hydraulicznych podczas przepływów cieczy w przewodach ciśnieniowych
Autorzy:
Urbanowicz, K.
Zarzycki, Z.
Powiązania:
https://bibliotekanauki.pl/articles/280429.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
transient flow
weighting function
friction losses
Opis:
Most papers dealing with calculations and simulations of the unsteady liquid pipe flow are based on the assumption that the formula for quasi-steady friction (Darcy-Weisbach formula) can be applied. In the case of fast changes, like fast transients e.g. water hammer, it fails. In this work, the wall shear stress is presented as a sum of quasi-steady and unsteady component. The unsteady component of the wall shear stress is modeled as a convolution of local fluid acceleration and a weighting function. The original weighting function has usually a very complicated structure, and what is more, makes impossible to carry out an efficient simulation of dynamical runs. In this paper, in order to enable efficient calculation of the unsteady component of the wall shear stress, new weighting functions are presented as sums of exponential components.
W dużej części prac, dotyczących obliczania oraz symulacji niestacjonarnego przepływu cieczy w przewodach ciśnieniowych, opory wyznacza się jedynie z dobrze znanej formuły Darcy-Weisbacha. Niestety w szybkozmiennych przepływach, takich jak np. uderzenie hydrauliczne, założenie quasi-stacjonarności oporów jest poważnym błędem. Wponiższej pracy naprężenie styczne na ściance przewodu wyznacza się z sumy quasi-stacjonarnego składnika oraz niestacjonarnego. Niestacjonarny składnik naprężenia stycznego modelowany jest jako splot lokalnego przyśpieszenia cieczy oraz funkcji wagi. Klasyczne funkcje wagi mają skomplikowaną postać, co uniemożliwia efektywne wyznaczanie oporów. W tej pracy przedstawione zostały nowe efektywne postacie funkcji wagowych o rozszerzonych zakresach stosowalności.
Źródło:
Journal of Theoretical and Applied Mechanics; 2012, 50, 2; 487-508
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An hourly reference evapotranspiration model as a tool for estimating plant water requirements
Autorzy:
Treder, W.
Klamkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/100923.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
weighting lysimeter
Penman-Monteith model
irrigation
Opis:
The usefulness of estimating hourly reference evapotranspiration for assessing the water requirements of plants over a 24-hour period was determined in the study. The values of hourly (ET0,h) and daily (ET0,d) evapotranspiration were calculated using the Penman-Monteith (PM) model. The daily ET0 was calculated automatically by the meteorological station, and the evapotranspiration values for individual hours were calculated using spreadsheet software. To verify the values of evapotranspiration calculated with these two approaches in relation to the actual water needs of grass, lysimetric measurements were performed. Additionally, substrate moisture content and temperature were measured using capacitance probes. The values of evapotranspiration estimated with the hourly PM model were higher than those determined with the daily model. An accuracy of the hourly model in relation to the data measured with a weighing lysimeter depended largely on the quality of the reproduction of meteorological parameters at the site of the crop. Observed underestimation of the actual daily evapotranspiration was presumably due to the use of air temperature values in the calculations (measured at a height of 2 m by the weather station). During strong solar radiation the air temperature was much lower than the temperature of the upper layer of the substrate in the weighing lysimeter. Reference evapotranspiration was recalculated by introducing into the hourly PM model the measured values of substrate temperature. After taking into consideration the higher temperatures, the calculated values of evapotranspiration increased, and the regression model took the form: y = 1.01x + 0.014 (R2 = 0.90), which proves the proportionality of the calculated and measured (actual water needs determined with the weighing lysimeter) data. Reliable data on the hourly variations in evapotranspiration over a 24-hour period can be a great tool for use in controlling the irrigation of plants grown in a limited volume of substrate.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2017, II/1; 469-481
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on face coloring entire weightings of plane graphs
Autorzy:
Jendrol, Stanislav
Šugerek, Peter
Powiązania:
https://bibliotekanauki.pl/articles/31232002.pdf
Data publikacji:
2014-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
entire weighting
plane graph
face colouring
Opis:
Given a weighting of all elements of a 2-connected plane graph $G = (V,E, F)$, let $f(α)$ denote the sum of the weights of the edges and vertices incident with the face α and also the weight of α. Such an entire weighting is a proper face colouring provided that $f(α) ≠ f(β)$ for every two faces α and β sharing an edge. We show that for every 2-connected plane graph there is a proper face-colouring entire weighting with weights 1 through 4. For some families we improved 4 to 3.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 2; 421-426
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Consistent Estimation of Cross-Classified Domains
Autorzy:
Lumiste, Kaur
Powiązania:
https://bibliotekanauki.pl/articles/466094.pdf
Data publikacji:
2011
Wydawca:
Główny Urząd Statystyczny
Tematy:
Consistent estimation
calibration
AC-calibration
repeated weighting
Opis:
Domain estimation has become an important area in survey sampling, however a lot of problems associate with it. One out of many is the lack of consistency between different surveys. The results of one survey do not coincide with the results of another survey done earlier or simultaneously, although the same variable is under study. We study two methods, AC-calibration (A – auxiliary, C – common) and repeated weighting (RW), for achieving consistency. A short overview of these two methods is given, and we develop formulas for a specified case, for the crossclassified domains. We assume that there are two sources of information on the study variables (either surveys or registers). The problem is that one source has information on domains formed by certain categorical variable, not considered or not identified in the other source. Instead, this second source has information on domains formed by another categorical variable. We are however interested in domains cross-classified with these categorical variables. A survey is done regarding these new domains, but the domain estimates will probably be inconsistent with marginal information, from earlier surveys. We require that the new domain estimates be consistent with the marginals. To achieve this we apply AC-calibration or repeated weighting. The formulas of AC-calibration and RW for the cross-classified domains are tested in a simulation study. Simulations were done on a population composed of real data from the Estonian Household Survey.
Źródło:
Statistics in Transition new series; 2011, 12, 2; 253-264
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-response and Weighting Systems in Business Tendency Surveys: Are Expectations Influenced?
Autorzy:
Tomczyk, Emilia
Kowalczyk, Barbara
Powiązania:
https://bibliotekanauki.pl/articles/500709.pdf
Data publikacji:
2011
Wydawca:
Szkoła Główna Handlowa w Warszawie
Tematy:
expectations
rationality
non-response
weighting
survey data
Opis:
Rationality of economic agents belongs to the basic assumptions of neoclassical economic theory, and for decades it has inspired research on whether expectations are indeed formed rationally. Direct data on expectations are available mainly through business tendency surveys which are subject to various types of non-response problems. Inclination of industrial enterprises to respond may be correlated with values of measured variable, introducing response bias. Response bias may also occur as a result of introducing weighting systems to control variable size of respondents. The two key properties of rational expectations, on which the majority of empirical analyses of survey data are focused, are unbiasedness and orthogonality. We analyze several sample balance statistics and expectations series based on quantified survey data, taking into consideration issues of non-response and weighting schemes. Alternative definitions of expectations series aim to account for: 1) influence of arbitrary assumptions concerning weighting of individual data, 2) changing sample structure that results from non-response, 3) response rates varying with degree of optimism / pessimism of respondents. Results of our analysis indicate that expectations concerning relative changes in production are unbiased but not efficient with respect to freely available information, namely, observed relative changes in production (lagged three months) and expectations balance (lagged two months). This result holds for a range of weighting schemes and non-response issues analyzed, including changes introduced to sample structure by non-response, and increased inclination of “optimists” and “pessimists” to supply answers in the business tendency survey, as long as their shares remain constant in time.
Źródło:
Prace i Materiały Instytutu Rozwoju Gospodarczego SGH; 2011, 86:Business Surveys, Business Cycles. Polish Contribution to the 30th CIRET Conference; 101-119
0866-9503
Pojawia się w:
Prace i Materiały Instytutu Rozwoju Gospodarczego SGH
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimating the substrate water status using capacitance measurements
Autorzy:
Klamkowski, K.
Treder, W.
Powiązania:
https://bibliotekanauki.pl/articles/101065.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
moisture sensor
irrigation
ornamental nursery
weighting lysimeter
Opis:
The suitability of capacitance probes for measuring the actual variations in substrate water content in container-grown ornamental species (Lawson cypress) was examined. The probes were installed in the plant containers. Weighing measurement data on water loss was used to assess the actual changes in substrate water content (plant water use). In an additional test, an evaluation of temperature sensitivity of the capacitance probe was performed under laboratory conditions. The probe was placed in a container containing the growing medium (peat substrate) with a defined (stable) moisture content. The substrate temperature was modified and the changes in probe output were recorded. The experiment demonstrated the existence of the effect of temperature on the quality of soil moisture measurements conducted with the capacitance method. The accuracy of the results obtained from measurements with dielectric sensors in relation to the data obtained by means of weighing platforms depended largely on the temperature profile of the measured medium. It was demonstrated that temperature variations explained 99% of the observed differences in the results of moisture content measured with the capacitance method. Due to the fact that there is no possibility of developing universal factors (for different sensors and substrates) for correcting the influence of temperature, this relationship should be defined independently for a given type of crop and the measuring system available.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2017, II/1; 521-533
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved method for simulating frictional losses in laminar transient liquid pipe flow
Autorzy:
Urbanowicz, K.
Zarzycki, Z.
Kudźma, S.
Powiązania:
https://bibliotekanauki.pl/articles/1943217.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska
Tematy:
unsteady pipe flow
unsteady friction
weighting function
Opis:
This paper is devoted to the problem of energy dissipation and it concerns unsteady friction modeling of the liquid flow in hydraulic lines. One dimensional (1D) quasi-steady model of energy dissipation is in common use. It means that the loss of energy is estimated by the Darcy-Weisbach formulae. Such an approximation is close to reality only for slow changes of the velocity field in the pipe cross-section. In case of fast changes, like fast transients, e.g. water hammer, it fails. In this work the wall shear stress (defined as an effect of unsteady fluid friction) is presented as a sum of quasi-steady and unsteady components. The unsteady component of the wall shear stress is modeled as an convolution of the local fluid acceleration and a weighting function w(t). The weighting function, in general, makes an allowance for a relation of the historic velocity changes and the unsteady component of the wall shear stress. Primitive weighting functions have usually very complicated structures, and what is more, they make it impossible to perform an efficient simulation of dynamical runs. In this paper, a new weighting function is presented as a sum of exponential components in order to enable efficient calculation of the unsteady component wall shear stress. A few examples of the new effective method of unsteady wall shear stress simulations, in case of the water hammer, are presented. The results of the calculations are compared with experiments known in literature and satisfying results are obtained.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2010, 14, 3; 175-188
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
APPLICABILITY OF THE EVIDEM MULTI-CRITERIA DECISION ANALYSIS FRAMEWORK FOR ORPHAN DRUGS – RESULTS FROM A STUDY IN 7 EURASIAN COUNTRIES.
Autorzy:
Baran-Kooiker, Aleksandra
ATIKELER, Kagan
GAITOVA, KAMILLA
HOLOWNIA-VOLOSKOVA, MALWINA
TURCU-STIOLICA, ADINA
Kooiker, Coen
PINIAZHKO, ORESTA
CZECH, MARCIN
Powiązania:
https://bibliotekanauki.pl/articles/895230.pdf
Data publikacji:
2019-06-28
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
rare diseases
MCDA
orphan drugs
EVIDEM
HTA
weighting
Opis:
Several Multi-Criteria Decision Analysis (MCDA) models for use in health technology assessment (HTA) have been developed over the years, including some for orphan drugs (OD). However, there is no general consensus yet on MCDA structure and which criteria should be included and implementation of MCDA into HTA practice has been slow so far. Our study tested the criteria preferences and possibilities for implementation of the EVIDEM MCDA framework for OD with a diverse group of 140 stakeholders in Kazakhstan, Netherlands, Poland, Romania, Russia, Turkey and Ukraine (KZ,NL,PL,RO,RU,TR,UA). The research elicited stakeholder preferences (weighting) for EVIDEM domains, criteria and sub-criteria to measure their relative importance. Correlations of work place and HTA/rare diseases experience with weighting results were investigated. Results showed that the ‘Need for intervention’ domain was assessed as the most important in: RO/NL/RU/TR, in KZ/PL the ‘Type of benefit of intervention’ and in UA ‘Economic consequences of intervention’. ‘Population Priorities’ was uniformly given a low priority. Further research, sharing of experiences and multi-stakeholder discussion is necessary to define a path forward for a robust and sustainable improvement of MCDA models and its application in orphan drug HTA. Model simplification and clarification of outcomes would be beneficial.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2019, 76, 3; 581-598
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Joint Calibration Estimator for dual frame surveys
Autorzy:
Elkasabi, Mahmoud A.
Heeringa, Steven G.
Lepkowski, James M.
Powiązania:
https://bibliotekanauki.pl/articles/465638.pdf
Data publikacji:
2015
Wydawca:
Główny Urząd Statystyczny
Tematy:
dual-frame estimation
calibration weighting
auxiliary variables
domain misclassification
Opis:
Many dual frame estimators have been proposed in the statistics literature. Some of these estimators are theoretically optimal but hard to apply in practice, whereas others are applicable but have larger variances than the first group. In this paper, a Joint Calibration Estimator (JCE) is proposed that is simple to apply in practice and meets many desirable properties for dual frame estimators. The JCE is asymptotically design unbiased conditional on the strong relationship between the estimation variable and the auxiliary variables employed in the calibration. The JCE achieves better performance when the auxiliary variables can fully explain the variability in the study variables or at least when the auxiliary variables are strong correlates of the estimation variables. As opposed to the standard dual frame estimators, the JCE does not require domain membership information. Even if included in the JCE auxiliary variables, the effect of the randomly misclassified domains does not exceed the random measurement error effect. Therefore, the JCE tends to be robust for the misclassified domains if included in the auxiliary variables. Meanwhile, the misclassified domains can significantly affect the unbiasedness of the standard dual frame estimators as proved theoretically and empirically in this paper.
Źródło:
Statistics in Transition new series; 2015, 16, 1; 7-36
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weighting function approximation in transient pipe flow
Autorzy:
Urbanowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/1933953.pdf
Data publikacji:
2012
Wydawca:
Politechnika Gdańska
Tematy:
numerical fluid mechanics
transient flow
hydraulic resistance
weighting function
Opis:
A very important problem in the transient liquid pipe flow analysis is accurate and effective modeling of hydraulic resistance. The so called integral convolution of the mean local acceleration of liquid and a weighting function need to be solved in a numerical way in order to simulate unsteady resistance. A necessary condition in effective numerical calculations is that the weighting function needs to be defined as a finite sum of exponential terms. The function keeps a constant shape in a laminar flow, in a turbulent flow, its shape changes and it is dependent on the instantaneous Reynolds number. In this article an easy method is presented to determine a proper weighting function in a very straightforward manner in a quick time. A comparison of the determined functions and function prototypes in a frequency domain will be presented as well.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2012, 16, 3-4; 263-276
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Missing Precipitation Data Estimation Using Long Short-Term Memory Deep Neural Networks
Autorzy:
Djerbouai, Salim
Powiązania:
https://bibliotekanauki.pl/articles/2086428.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
Hodna
K'sob basin
missing precipitation data
long short-term memory
CCWM
coefficient of correlation weighting method
IDWM
inverse distance weighting method
Opis:
Due to the spatiotemporal variability of precipitation and the complexity of physical processes involved, missing precipitation data estimation remains as a significant problem. Algeria, like other countries in the world, is affected by this problem. In the present paper, Long Short-Term Memory (LSTM) deep neural Networks model was tested to estimate missing monthly precipitation data. The application was presented for the K'sob basin, Algeria. In the present paper, the optimal architecture of LSTM model was adjusted by trial-and-error-procedure. The LSTM model was compared with the most widely used classical methods including inverse distance weighting method (IDWM) and the coefficient of correlation weighting method (CCWM). Finally, it was concluded that the LSTM model performed better than the other methods.
Źródło:
Journal of Ecological Engineering; 2022, 23, 5; 216--225
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-objective optimization of dielectric layer photonic crystal filter
Autorzy:
Yang, H.
Huang, C.
Meng, S.
Powiązania:
https://bibliotekanauki.pl/articles/174482.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
filter
photonic crystal
weighting factors method
response surface methodology
RSM
Opis:
The weighting factors method and the response surface methodology are used to achieve multi-objective optimization of a dielectric layer photonic crystal filter. The size of period and the transmission quantity are considered simultaneously and a multi-objective optimization model of filter is established, which takes the size of period and transmission quantity to be minimized in stop-band as objectives. Global approximate expressions of the objective and the constraint functions are found by response surface methodology. Then the weighting factors method is employed to convert the model into a quadratic programming model and the optimal parameters can be obtained using sequence quadratic programming. Examples provide the optimized results in three different weight coefficients. The effect of the weighting factors on the value of the objective function is also discussed. Results show that the present method is precise and efficient for multi-objective optimization of a dielectric layer photonic crystal filter.
Źródło:
Optica Applicata; 2017, 47, 1; 29-40
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of deteministic interpolation methods for the estimation of groundwater level
Autorzy:
Kamińska, A.
Grzywna, A.
Powiązania:
https://bibliotekanauki.pl/articles/123402.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
radial basis functions
Inverse Distance Weighting
groundwater levels
prediction maps
Opis:
This paper compares two spatial interpolation techniques – Radial Basis Functions (RBF) and Inverse Distance Weighting (IDW) – with the goal of determining which method creates the best representation of reality for measured groundwater levels in catchment area. The study used the results of research and field observations from the year 2011, in Sosnowica (West Polesie). The data set consists of groundwater levels measured at 15 points in three series of tests. Surface generation was obtained for each method. The water prediction maps showed spatial variation in the groundwater level in the study area and they are quite different. RBF method resulted in a smoother map. The analysis of the methods of interpolation of analyzed data with the help of cross validation statistics and plots showed that Radial Basis Functions creates better representation of reality for measured groundwater levels.
Źródło:
Journal of Ecological Engineering; 2014, 15, 4; 55-60
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Universal weighting function in modeling transient cavitating pipe flow
Uniwersalna funkcja wagi w modelowaniu niestacjonarnych przepływów z kawitacją występujących w przewodach ciśnieniowych
Autorzy:
Urbanowicz, K.
Zarzycki, Z.
Kudźma, S.
Powiązania:
https://bibliotekanauki.pl/articles/281804.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
transient pipe flow
unsteady wall shear stress
weighting function
cavitation
Opis:
This work concerns modeling of time-varying resistance during transient cavitating liquid pipe flow. The wall shear stress is presented in the way introduced by Zielke as the integral convolution of liquid local velocity changes and a weighting function. A new procedure for determination, so-called, a universal laminar-turbulent weighting function, which combines functions of Zielke and Vardy and Brown or Zielke and Zarzycki, is presented. Based on these weighting functions, the method of simulation transients in the pressure lines in a wide range of Reynolds numbers is presented. It eliminates numerical problems associated with the change of laminar flow into turbulent and vice versa. An example application of this method for simulation of water hammer is presented. The calculation results are compared against experiments presented by Bergant and Simpson, and good agreement is found.
Praca dotyczy modelowania zmiennych w czasie oporów podczas nieustalonego przepływu cieczy w przewodach ciśnieniowych. Naprężenie styczne na ściance przewodu przedstawione zostało w klasyczny sposób (wg. Zielke) jako całka splotowa z przyśpieszenia cieczy i pewnej funkcji wagowej. Przedstawiono procedury wyznaczania dwóch uniwersalnych funkcji wagowych laminarnoturbulentnych (wg. Zielke i Vardy-Browna oraz wg. Zielke i Zarzyckiego).W oparciu o te funkcje przedstawiono metodę modelowania (symulacji) przebiegów przejściowych w przewodach ciśnieniowych w szerokim zakresie liczb Reynoldsa. Eliminuje on problemy natury numerycznej związane z przechodzeniem min. z przepływu laminarnego w turbulentny i odwrotnie. Podano przykład zastosowania opracowanej metody do symulacji uderzenia hydraulicznego. Wyniki obliczeń porównano z wynikami eksperymentalnymi wg. Berganta i Simpsona, otrzymując dobrą zgodność.
Źródło:
Journal of Theoretical and Applied Mechanics; 2012, 50, 4; 889-902
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern modeling of water hammer
Autorzy:
Urbanowicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/259738.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
hydraulic system
cavitation
water hammer
wall shear stress
weighting function
Opis:
Hydraulic equipment on board ships is common. It assists in the work of: steering gear, pitch propellers, watertight doors, cargo hatch covers, cargo and mooring winches, deck cranes, stern ramps etc. The damage caused by transient flows (which include among others water hammer) are often impossible to repair at sea. Hence, it is very important to estimate the correct pressure runs and associated side effects during their design. The presented study compares the results of research on the impact of a simplified way of modeling the hydraulic resistance and simplified effective weighting functions build of two and three-terms on the estimated results of the pressure changes. As it turns out, simple effective two-terms weighting functions are able to accurately model the analyzed transients. The implementation of the presented method will soon allow current automatic protection of hydraulic systems of the adverse effects associated with frequent elevated and reduced pressures.
Źródło:
Polish Maritime Research; 2017, 3; 68-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of weights on the quality of agricultural producers multicriteria decision models
Autorzy:
Sielska, A.
Powiązania:
https://bibliotekanauki.pl/articles/406633.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Farm Accountancy Data Network (FADN)
agricultural producers
weighting methods
multiple criteria
Opis:
Decisions regarding agricultural production involve multiple goals. A multicriteria approach allows decision makers to consider more aspects of the decision scenario, although it also leads to other problems, such as difficulties with the selection of goals or criteria, as well as assigning them appropriate weights. It is argued that not only do goals vary depending on the decision-makers’ socioeconomic features, but their relative importance changes as well. A simulation study has been conducted based on the Farm Accountancy Data Network (FADN) database. We use the distance-to-the-negative-solution maximization model. Seven sets of criteria and different sets of weights are considered. The main purpose of the study is to determine the impact of weights on the quality of the model. Quality is assessed by comparing the optimal and observed values of the decision variables. The results lead to the conclusion that the differences between the quality of various models are small.
Źródło:
Operations Research and Decisions; 2015, 25, 4; 51-69
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local dependency in networks
Autorzy:
Kudělka, M.
Zehnalová, Š.
Horák, Z.
Krömer, P.
Snášel, V.
Powiązania:
https://bibliotekanauki.pl/articles/330805.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
complex networks
graphs
edge weighting
dependency
sieć złożona
grafy
zależność lokalna
Opis:
Many real world data and processes have a network structure and can usefully be represented as graphs. Network analysis focuses on the relations among the nodes exploring the properties of each network. We introduce a method for measuring the strength of the relationship between two nodes of a network and for their ranking. This method is applicable to all kinds of networks, including directed and weighted networks. The approach extracts dependency relations among the network's nodes from the structure in local surroundings of individual nodes. For the tasks we deal with in this article, the key technical parameter is locality. Since only the surroundings of the examined nodes are used in computations, there is no need to analyze the entire network. This allows the application of our approach in the area of large-scale networks. We present several experiments using small networks as well as large-scale artificial and real world networks. The results of the experiments show high effectiveness due to the locality of our approach and also high quality node ranking comparable to PageRank.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2015, 25, 2; 281-293
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of irrigation requirements and crop coefficients using weighing lysimeters in perennial plants
Autorzy:
Treder, J.
Treder, W.
Klamkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/101548.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
ornamental nurseries
evapotranspiration
crop coefficient Kc
weighting lysimeter
automatic irrigation systems
Opis:
The increasing role of perennials in ornamental nurseries requires the elaboration of efficient and accurate irrigation control of this specific group of plants. The experiment was conducted in 2015 in Research Institute of Horticulture, in Skierniewice. The aim of the study was to determine the water requirements and designate the specific evapotranspiration crop coefficient Kc of several perennials, commonly grown in Polish ornamental nurseries. Water requirements of perennials were evaluated using weighing lysimeters. At the same time the recorded climate parameters allowed to calculate the potential evapotranspiration (ET0). Lysimeter measurements and meteorological data allowed determine specific to each species crop coefficient (Kc). The Kc values were determined by dividing ETc by ET0. The obtained results showed that irrespectively of plant growth phase there is strong correlation between climate parameters and real crop evapotranspiration (ETc) of six evaluated perennials: Anemone hupehensis ‚Prinz Heinrich’, Echinacea purpurea ‘Guava Ice’, Hemerocallis, ‘Sandra Elisabeth’, Salvia nemorosa ‘Mainacht’ and Veronica spicata ‘Royal Candles Glory’. The Kc coefficients of all species were changed during the growth season and increased according to plant development and percentage of ground coverage of soil in the lysimeter by leaves. The strong, positive correlation was shown for daily and hourly calculated crop evapotranspiration and potential evapotranspiration (ET0) obtained from weather station. Determination of crop coefficients for ornamental perennials is essential for precise calculation of water doses and irrigation controlling in the nurseries.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2017, III/2; 1213-1228
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy cycles in weighted graphs
Autorzy:
Bondy, J.
Broersma, Hajo
van den Heuvel, Jan
Veldman, Henk
Powiązania:
https://bibliotekanauki.pl/articles/743527.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
weighted graph
(long, optimal, Hamilton) cycle
(edge-, vertex-)weighting
weighted degree
Opis:
An (edge-)weighted graph is a graph in which each edge e is assigned a nonnegative real number w(e), called the weight of e. The weight of a cycle is the sum of the weights of its edges, and an optimal cycle is one of maximum weight. The weighted degree w(v) of a vertex v is the sum of the weights of the edges incident with v. The following weighted analogue (and generalization) of a well-known result by Dirac for unweighted graphs is due to Bondy and Fan. Let G be a 2-connected weighted graph such that w(v) ≥ r for every vertex v of G. Then either G contains a cycle of weight at least 2r or every optimal cycle of G is a Hamilton cycle. We prove the following weighted analogue of a generalization of Dirac's result that was first proved by Pósa. Let G be a 2-connected weighted graph such that w(u)+w(v) ≥ s for every pair of nonadjacent vertices u and v. Then G contains either a cycle of weight at least s or a Hamilton cycle. Examples show that the second conclusion cannot be replaced by the stronger second conclusion from the result of Bondy and Fan. However, we characterize a natural class of edge-weightings for which these two conclusions are equivalent, and show that such edge-weightings can be recognized in time linear in the number of edges.
Źródło:
Discussiones Mathematicae Graph Theory; 2002, 22, 1; 7-15
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of 1x5 Planar Array Microstrip Antenna with Edge Weighting to Increase Gain
Autorzy:
Simanjuntak, Imelda Uli Vistalina
Sulistyaningsih
Heryanto
Astuti, Dian Widi
Powiązania:
https://bibliotekanauki.pl/articles/27311953.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
microstrip antenna
edge weighting
parasitic patch
proximity coupling
5G antenna gain
Opis:
Research on improving the performance of microstrip antennas is continuously developing the following technology; this is due to its light dimensions, cheap and easy fabrication, and performance that is not inferior to other dimension antennas. Especially in telecommunications, microstrip antennas are constantly being studied to increase bandwidth and gain according to current cellular technology. Based on the problem of antenna performance limitations, optimization research is always carried out to increase the gain to become the antenna standard required by 5G applications. This research aims to increase the gain by designing a 5-element microstrip planar array antenna arrangement at a uniform distance (lamda/2) with edge weights at a frequency of 2.6 GHz, Through the 1x5 antenna design with parasitic patch, without parasitic, and using proximity coupling.This study hypothesizes that by designing an N-element microstrip planar array antenna arrangement at uniform spacing (lamda/2) with edge weights, a multi-beam radiation pattern character will be obtained so that to increase gain, parasitic patches contribute to antenna performance. This research contributes to improving the main lobe to increase the gain performance of the 1x5 planar array antenna. Based on the simulation results of a 1x5 microstrip planar array antenna using a parasitic patch and edge weighting, a gain value of 7.34 dB is obtained; without a parasitic patch, a gain value of 7.03 dB is received, using a parasitic patch and proximity coupling, a gain value of 2.29 dB is obtained. The antenna configuration with the addition of a parasitic patch, even though it is only supplied at the end (edge weighting), is enough to contribute to the parameters impedance, return loss, VSWR, and total gain based on the resulting antenna radiation pattern. The performance of the 1x5 microstrip planar array antenna with parasitic patch and double substrate (proximity coupling), which is expected to contribute even more to the gain side and antenna performance, has yet to be achieved. The 1x5 planar array antenna design meets the 5G gain requirement of 6 dB.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 4; 683--690
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bootstrap Method with Calibration for Standard Error Estimators of Income Poverty Measures
Autorzy:
Zięba-Pietrzak, Agnieszka
Kordos, Jan
Wieczorkowski, Robert
Powiązania:
https://bibliotekanauki.pl/articles/465812.pdf
Data publikacji:
2011
Wydawca:
Główny Urząd Statystyczny
Tematy:
Auxiliary information
Bootstrap
Calibration
Complex sample surveys
EU-SILC
Poverty indicators
Weighting
Opis:
The authors begin with calibration approach in sample surveys, focussing on the Eurostat approach. Next, the indicators of poverty and social exclusion are discussed as an essential tool for monitoring progress in the reduction of these problems. Most of these indicators are calculated according to the Eurostat recommendations, using data from European Statistics on Income and Living Conditions (EU-SILC). Complex sample design of the EU-SILC requires weighted analyses for estimates of population parameters and approximate methods of standard error estimation. In our study McCarthy and Snowden (1985) bootstrap method for standard errors estimation of income poverty measures is presented. In the next step the reweighting of bootstrap weights is applied and results of such calibration are discussed.
Źródło:
Statistics in Transition new series; 2011, 12, 1; 81-96
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Virtual–real fusion maintainability verification based on adaptive weighting and truncated spot method
Autorzy:
Ge, Zhexue
Zhang, Yi
Wang, Fang
Luo, Xu
Yang, Yongmin
Powiązania:
https://bibliotekanauki.pl/articles/2200935.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
virtual–real fusion maintainability
maintainability verification
adaptive weighting method
truncated SPOT method
Opis:
Maintainability is an important general quality characteristic of products. Insufficient maintainability will lead to long maintenance time and high maintenance cost, thus affecting the availability of products. Maintainability verification is an important means to ensure maintainability meets design requirements. However, the cost of traditional real maintainability verification method is very high, and the virtual maintenance method has insufficient verification accuracy due to the lack of large maintenance force feedback when the human body is moving. In order to reduce the evaluation error and test sample size, the paper conducts maintainability verification based on the mixed physical and virtual maintainability test scenarios. Aiming at the problem that traditional methods are difficult to deal with the real test information and synchronous virtual simulation information in the test process, this study proposes a virtual–real fusion maintainability evaluation algorithm based on adaptive weighting and truncated SPOT (Sequential Posterior Odd Test) method. It can weigh real test information and virtual human simulation information adaptively to obtain a virtual–real fusion maintainability test sample. Then, the SPOT method is used to evaluate the maintainability of small samples. The adjustment of valve clearance, replacement of air filter element and replacement of starting motor maintenance tasks of ship engine are taken as examples for demonstration. The virtual–real fusion and virtual maintainability verification methods are respectively used for verification, and compared with the physical maintenance scenario constructed by 3D printing, indicating that the accuracy of virtual–real fusion maintainability test verification is 89%, while the virtual maintainability verification is only 33%.
Źródło:
Eksploatacja i Niezawodność; 2022, 24, 4; 738--746
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nielojalne szable? O badaniu zaplecza prezydenta miasta in spe za pomocą zmodyfikowanej metody AHP
Disloyal followers? About the study on political base of the mayor in spe using modified method of AHP
Autorzy:
Drzonek, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/514435.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Śląski. Wydział Nauk Społecznych
Tematy:
mayor
political preferences
AHP
method of weighting the selection preferences
local elections
Opis:
The article contents some results of research on political preferences of candidates for City Council in Szczecin. The survey was done just before the 2014 local elections. In the survey’s results published in this paper, the main object was to determine the relation of candidates for councilors to competition for the mayor of Szczecin. The analysis is focused on the issues of mayor’s potential attributes such as: previous achievements, personal competence, image, party affiliation and program for action in future. Moreover the concentration was also done on preferences of mayor’s candidates: it was very interesting to compare answers on the question who would be better mayor of Szczecin. In the research the modified Analytic Hierarchy Process methods was used. Firstly, the modification, called the method of weighting the selection preferences, showed Piotr Krzystek (mayor of Szczecin since 2006) as a most preferred pretender in 2014 - the majority of party electoral committees recognized him as a second choice candidate. Secondary, each electoral committee had disloyal followers.
Źródło:
Political Preferences; 2016, 12; 57-71
2449-9064
Pojawia się w:
Political Preferences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania możliwości zastąpienia barytu kredą w obciążonej płuczce poliglikolowej z polimerem PT-51 do przewiercania skał ilastych
Barite replacement with chalk in weighted polyglycol drilling mud with PT-51 polymer to drilling in clays and shales - lab research
Autorzy:
Kopeć, P.
Wysocki, S.
Powiązania:
https://bibliotekanauki.pl/articles/300495.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
płuczki wiertnicze
materiały obciążające
baryt
kreda
drilling muds
weighting agents
barite
chalk
Opis:
Prawidłowe obciążenie płuczki jest bardzo ważne dla procesu wiercenia, aby zrównoważyć ciśnienia złożowe oraz wywierać przeciwciśnienie na ściany otworu. W przypadku niewłaściwie dobranej płuczki wiertniczej do przewiercania skał ilastych obserwuje się efekt "płynięcia skał". Aby temu zapobiegać stosuje się płuczki o podwyższonej gęstości. Stosowane do obciążania płuczek materiały powinny być obojętne chemicznie względem składników płuczki oraz nie powinny wpływać znacząco na parametry technologiczne, dodatkowo, ze względu na duże zużycie, powinny być łatwodostępne oraz tanie. W niniejszej pracy przebadano możliwość zastąpienia barytu kredą w obciążonej płuczce poliglikolowej do przewiercania skał ilastych. Przeprowadzone badania wykazały, że użycie kredy i barytu w skomponowanej płuczce poliglikolowej skutecznie obciąża płuczkę do gęstości 1,5 g/cm3, bez znaczącego wpływu na parametry reologiczne. Kreda wpływa podobnie jak baryt na parametry technologiczne, przy czym posiada mniejsze właściwości ścierne i jest tańsza od barytu.
The right weighting of drilling mud is very important for drilling to balance well pressure and exert back pressure to the walls. In instance to wrong match of drilling mud, there is a crawling rocks effect. In order to prevent this effect, drilling mud with high density are use. Materials which we use to weighting should be a chemical inertness to other components of mud and don't change of technological parameters. Because of high consumption it also should be easily accessible and cheap. In this work we research for replacement barite by chalk in weighted polyglycol drilling mud to reboring clays and shales. Research show that using a chalk and barite on prepared mud successfully weight it to density of 1.5 g/cm3 without significant influence of rheological parameters. Chalk influence similarly like barite at technological parameters and have lower abrasiveness and it's cheaper than barite.
Źródło:
Wiertnictwo, Nafta, Gaz; 2010, 27, 1--2; 217-223
1507-0042
Pojawia się w:
Wiertnictwo, Nafta, Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of multi-valued weighting logical functions in the analysis of a degree of importance of construction parameters on the example of hydraulic valves
Autorzy:
Deptuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/955221.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
pompa
zawór hydrauliczny
optymalizacja
optimization process
weighting logical coefficients
hydraulic valves
pomps
Opis:
In the optimization process, changes in the construction parameters value influence the behaviour of functions depending on time. Weighting logical coefficients for the stabilisation time are taken into consideration here, i.e., a shorter (better) stabilisation time has a more important (bigger) value of the weighting coefficient. An example of applying weighting logical functions in the analysis of a degree of importance of construction parameters of a hydraulic valve is presented in the paper.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 3; 539-548
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Oriented Version of the 1-2-3 Conjecture
Autorzy:
Baudon, Olivier
Bensmail, Julien
Sopena, Éric
Powiązania:
https://bibliotekanauki.pl/articles/31339138.pdf
Data publikacji:
2015-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
oriented graph
neighbour-sum-distinguishing arc-weighting
complexity
1-2-3 Conjecture
Opis:
The well-known 1-2-3 Conjecture addressed by Karoński, Luczak and Thomason asks whether the edges of every undirected graph $G$ with no isolated edge can be assigned weights from {1, 2, 3} so that the sum of incident weights at each vertex yields a proper vertex-colouring of $G$. In this work, we consider a similar problem for oriented graphs. We show that the arcs of every oriented graph \(\overrightarrow{G}\) can be assigned weights from {1, 2, 3} so that every two adjacent vertices of \(\overrightarrow{G}\) receive distinct sums of outgoing weights. This result is tight in the sense that some oriented graphs do not admit such an assignment using the weights from {1, 2} only. We finally prove that deciding whether two weights are sufficient for a given oriented graph is an $\mathsf{NP}$-complete problem. These results also hold for product or list versions of this problem.
Źródło:
Discussiones Mathematicae Graph Theory; 2015, 35, 1; 141-156
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Saving Robust Control of Active Magnetic Bearings in Flywheel
Autorzy:
Mystkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/386963.pdf
Data publikacji:
2012
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
koło zamachowe
aktywne łożysko magnetyczne
weighting functions
flywheel
active magnetic bearings
singular control
Opis:
The paper reports on the investigation and development of the flywheel device as a energy storage system (FESS). The FESS is designed to operate in a vacuum and is supported on a low energy controlled active magnetic bearings (AMBs). The goal was to design and experimentally test the self integrated flywheel conception with a smart control of the flywheel rotor magnetic suspension. The low power control approach, with the reduced bias current, of the flywheel active magnetic bearings is used. The weighting functions are designed in order to meet robust control conditions. The laboratory investigations of the flywheel with high gyroscopic effect operated at low speed met the control and energy performances requirements.
Źródło:
Acta Mechanica et Automatica; 2012, 6, 3; 72-75
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparative study of 2DOF PID and 2DOF fractional order PID controllers on a class of unstable systems
Autorzy:
Bingi, K.
Ibrahim, R.
Karsiti, M. N.
Hassan, S. M.
Harindran, V. R.
Powiązania:
https://bibliotekanauki.pl/articles/229519.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fractional order controller
set-point weighting
2DOF PID
process control
unstable systems
Opis:
The proportional-integral-derivative (PID) controllers have experienced series of structural modifications and improvements. Example of such modifications are set-point weighting and fractional ordering. While the former is to achieve two-degree-of-freedom (2DOF) ability of set-point tracking and disturbance rejection, the latter is to ensure smooth control action. Therefore, this paper reviews various forms of PID controllers and provides a comparative analysis of 2DOF PID and 2DOF fractional order PID (FOPID) controllers. The paper also discusses the conversion of one PID form to another. For the comparative analysis of the various controllers, a class of unstable systems are considered. Simulation result shows that in most cases the conversion from one form to another does not significantly affect the performance of the system. It is also observed that the 2DOF controllers (2DOF PID and 2DOF FOPID) improved significantly the performance of the ordinary PID controllers.
Źródło:
Archives of Control Sciences; 2018, 28, 4; 635-682
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The PROMETHEE II method in multi-criteria evaluation of cryptocurrency exchanges
Metoda PROMETHEE II w wielokryterialnej ocenie giełd kryptowalut
Autorzy:
Kądziołka, K.
Powiązania:
https://bibliotekanauki.pl/articles/2048732.pdf
Data publikacji:
2021
Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Tematy:
k-means algorithm
hierarchical clustering
cryptocurrency exchanges
composite indicator
weighting scheme
PROMETHEE II
Opis:
Subject and purpose of work: The aim of this work is to present the application possibilities of PROMETHEE II method used to create a ranking of cryptocurrency exchanges as well as comparing the results of multi-criteria and multi-dimensional analysis. A simulation method for determining the weights of criteria is proposed, which maximizes the similarity of the final ranking to the other ones. Materials and methods: PROMETHEE II method and taxonomic measure were used to create rankings of exchanges. Hierarchical clustering combined with the k-means algorithm was used to identify groups of exchanges with a similar level of the values of net flows. Publicly available data published on the Internet were analysed. Results: There was a high consistency in the ordering of exchanges when a multi-criteria and a multi-dimensional approach were used. Four groups of exchanges with a similar level of the values of net flows were identified. Exchanges in group one were characterized by the highest average net flows. Conclusions: The multi-criteria approach can be used as an alternative to the multi-dimensional assessment of cryptocurrency exchanges. The proposed simulation method for determining the weights of criteria can be helpful in case the researcher has no information about the importance of the criteria.
Źródło:
Economic and Regional Studies; 2021, 14, 2; 131-145
2083-3725
2451-182X
Pojawia się w:
Economic and Regional Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Objective weights for scoring: the automatic democratic method
Autorzy:
Tofallis, Chris
Powiązania:
https://bibliotekanauki.pl/articles/2216202.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Ekonomiczny w Katowicach
Tematy:
multi attribute decision making
weighting
ranking
performance measurement
composite indices
data envelopment analysis
Opis:
When comparing performance (of products, services, entities, etc.), multiple attributes are involved. This paper deals with a way of weighting these attributes when one is seeking an overall score. It presents an objective approach to generating the weights in a scoring formula which avoids personal judgement. The first step is to find the maximum possible score for each assessed entity. These upper bound scores are found using Data Envelopment Analysis. In the second step the weights in the scoring formula are found by regressing the unique DEA scores on the attribute data. Reasons for using least squares and avoiding other distance measures are given. The method is tested on data where the true scores and weights are known. The method enables the construction of an objective scoring formula which has been generated from the data arising from all assessed entities and is, in that sense, democratic.
Źródło:
Multiple Criteria Decision Making; 2022, 17; 69-84
2084-1531
Pojawia się w:
Multiple Criteria Decision Making
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integration of Late Glacial and Holocene pollen data from Poland
Autorzy:
Walanus, A.
Nalepka, D.
Powiązania:
https://bibliotekanauki.pl/articles/973646.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
palynology
isopollen maps
radiocarbon dating
weighting function
bootstrapping
Vistulian Late Glacial
Holocene
Polska
Opis:
Quaternary palynological data are stored in tables which are typical computer database objects. The individual pollen table, in order to be integrated with other tables using computer-based methods, has to be attributed with (1) geographical coordinates, (2) dates attached to each row (sample) of the table, and (3) taxa names, common to all tables, attached to each column. In this paper, integration of individual lists of palynological taxa is shortly described, and some remarks are given on extracting data for selected time slices. The problem of dating of all pollen spectra, while few radiocarbon dates are available in the profile, is considered. Some mathematical models of age-depth relation are proposed, as well as incorporation of information derived from lithology of the profile. The algorithm of integration (averaging) of pollen percentages on the map of Poland is discussed. The techniques of bootstrap and so-called removed residuals are proposed as tools for assessment of reliability of isopollen lines. A possibility of construction of migration (rate of change) maps is also mentioned. The presented algorithm has been used to obtain hundreds of isopollen maps for the Holocene in the area of Poland .
Źródło:
Annales Societatis Geologorum Poloniae; 2004, 74, No 3; 285-294
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A bi-objective portfolio optimization with conditional value-at-risk
Autorzy:
Sawik, B.
Powiązania:
https://bibliotekanauki.pl/articles/375981.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
multi-criteria decision making
portfolio optimization
conditional value-at-risk
weighting approach
linear programming
Opis:
This paper presents a bi-objective portfolio model with the expected return as a performance measure and the expected worst-case return as a risk measure. The problems are formulated as a bi-objective linear program. Numerical examples based on 1000, 3500 and 4020 historical daily input data from the Warsaw Stock Exchange are presented and selected computational results are provided. The computational experiments prove that the proposed linear programming approach provides the decision maker with a simple tool for evaluating the relationship between the expected and the worst-case portfolio return.
Źródło:
Decision Making in Manufacturing and Services; 2010, 4, 1-2; 47-69
1896-8325
2300-7087
Pojawia się w:
Decision Making in Manufacturing and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Soil Pollution Levels in Al-Qadisiyah Governorate, Iraq Using Contamination Index and GIS
Autorzy:
Al-Khuzaie, Marwah M.
Abdul Maulud, Khairul Nizam
Powiązania:
https://bibliotekanauki.pl/articles/2068473.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
geo-accumulation index
pollution load index
trace element variation
inverse distance weighting
bayesian kriging
Opis:
The precise determination of trace element concentrations in the soil of the Al-Qadisiyah Governorate is part of the Iraqi sedimentary plain is required to eliminate high levels of harmful elements in polluted soils. The soil samples were collected from 28 representative profiles in Al-Shamiyah city. The soil profiles were defined using virtual characterization. In this study, I-geo was used to analyze soil pollution. The goals and destinations of the I-geo readings Contamination of Cd, Ni, Pb, and Zn in various soil strata. I-geo (Cd) generally range from 0.58 to 4.71, I-geo (Ni) range from 0.09 to 4.07, I-geo (Pb) ranged range from 0.07 to 2.79, and I-geo (Zn) ranges from zero to 2.79, depicting the local differences in I-geo for pollutants in the research area. Suggesting that the research area had been heavily polluted from Cd in the varied layers of the soils. On the maps pertaining to Zn and Pb, the majority of the research area was primarily covered in the orange and blue hues, suggesting that a significant portion of the research area was likely to be severely polluted from Cd and Ni. Moreover, the land cover layouts of Ni in layers of the soils revealed concentrations rising towards to the western sections, which could be attributed to proximity to a major drain. The results display that its I-geo value of four trace metals generally range from non-pollute to significantly heavily polluted. The I-geo data show significant differences in levels of the Ni, Cd, Zn, and Pb in different soils strata. Including these findings, the soil in Al-Shamiya, Al-Qadisiyah Governorate contains high levels of Cd, Ni, Pb, and Zn. Industries of fossil fuel combustion, as well as other man-made wastes include agricultural nutrients, soil conditioners, and sludge, particularly, ammonium phosphate pollution in soils. The pollutant load index (PLI) reveals a baseline level of contamination in 28 locations, as well as a decline in soil quality in four others. Finally, assessing the danger of contamination for trace metals utilizing the I-geo and PLI by using the GIS method and multimodal models is a helpful and relevant strategy.
Źródło:
Journal of Ecological Engineering; 2022, 23, 3; 206--213
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
``A Mathematical Look at Politics” by E. Arthur Robinson, Jr., Daniel H. Ullman
Autorzy:
Mercik, Jacek W.
Powiązania:
https://bibliotekanauki.pl/articles/748443.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
voting procedures, social choice function, divisor methods, game, conflict, Nash equilibrium, weighting voting, privileges
Opis:
The 460-page book “A Mathematical Look at Politics” (E. Arthur Robinson, Jr. and Daniel H. Ull-man. A mathematical look at politics. CRC Press–Taylor and Francis Group, Boca Raton, FL, 2011. ISBN: 978-1-4398-1983-8) written by Arthur Robinson and Daniel Ullman [1]   consists of four chapters (the descriptions of the chapters are given in parenthesis): I --- Voting (the two candidate case,  social choice functions, criteria for social choice, which methods are good?,  Arrow’s theorem, variations on a theme), II --- Apportionment (Hamilton’s Method, Divisor Methods, Criteria and Impossibility, the Method of Balinski and Young, Choosing a Divisor Method, History of Apportionment in the United States), III --- Conflict (Strategies and Outcomes, Chance and Expectation, Solving Zero-Sum Games, Conflict, Nash Equilibria, the Prisoner’s Dilemma) and chapter IV --- the Electoral College (Weighted Voting and Privileges). At the end of each chapter there are problems and exercises. Finally, solutions to the exercises and problems, bibliography and index are at the end. Recommendations for instructors are also presented at the end of the preface. In the preface, one may find the declaration of the Authors that this book focuses on mathematical reasoning about politics rather than on mathematics:--  Is there a good way to choose winners of elections?--  Is there a good way to apportion congressional seats?--  Is there a good way to make decisions in situations of conflict and uncertainty?The book offers an alternative textbook to the usual mathematics courses for liberal arts students seeking to meet a general education requirement in mathematics or quantitative reasoning. What makes this book mathematical is not numbers or formulas, but rather reasoning. The book requires rather little background in mathematics or political science. Some experience with the American system of government is assumed.
Źródło:
Mathematica Applicanda; 2013, 41, 2
1730-2668
2299-4009
Pojawia się w:
Mathematica Applicanda
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Effective Speaker Clustering Method using UBM and Ultra-Short Training Utterances
Autorzy:
Hossa, R.
Makowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/176593.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
automatic speech recognition
interindividual difference compensation
speaker clustering
universal background model
GMM weighting factor adaptation
Opis:
The same speech sounds (phones) produced by different speakers can sometimes exhibit significant differences. Therefore, it is essential to use algorithms compensating these differences in ASR systems. Speaker clustering is an attractive solution to the compensation problem, as it does not require long utterances or high computational effort at the recognition stage. The report proposes a clustering method based solely on adaptation of UBM model weights. This solution has turned out to be effective even when using a very short utterance. The obtained improvement of frame recognition quality measured by means of frame error rate is over 5%. It is noteworthy that this improvement concerns all vowels, even though the clustering discussed in this report was based only on the phoneme a. This indicates a strong correlation between the articulation of different vowels, which is probably related to the size of the vocal tract.
Źródło:
Archives of Acoustics; 2016, 41, 1; 107-118
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rozszerzony algorytm PID dla przemysłowego regulatora temperatury z samostrojeniem
Extended PID algorithm for industrial temperature controller with self-tuning
Autorzy:
Świder, Z.
Trybus, L.
Powiązania:
https://bibliotekanauki.pl/articles/276765.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
algorytm PID
samostrojenie przekaźnikowe
ważona wielkość zadana
PID control
set-point weighting
relay self-tuning
Opis:
Regulator PID z ważoną wielkością zadaną pozwala w pewnym zakresie zmniejszyć przeregulowanie na skokową zmianę wielkości zadanej, jednocześnie nie zmieniając odpowiedzi na zakłócenie (sprowadzone na wejście obiektu). Uzyskuje się to poprzez wprowadzenie „wagi” b w różnicy b W–Y, co ogranicza wpływ wielkości zadanej w torze P regulatora (W oznacza wielkość zadaną, a Y wyjście obiektu). Zmniejszając wartość współczynnika b można ograniczyć lub też całkowicie wyeliminować przeregulowanie w odpowiedzi na skokową zmianę wielkości zadanej W. Jednak dla nastaw regulatora otrzymanych w wyniku samostrojenia przekaźnikowego przy typowym zapasie wzmocnienia i fazy, przeregulowanie występuje nawet dla b=0. W artykule przedstawiono propozycję rozszerzenia algorytmu PID z ważoną wielkością zadaną o filtr pozwalający całkowicie wyeliminować to przeregulowanie.
PID controller with set-point weighting allows to correct set-point response without affecting disturbance response. This is done by means of a factor b in the difference b W–Y which determines proportional action of the controller (W denotes set-point and Y, plant output). By decreasing b one can reduce or even eliminate overshoot of set-point response. It turns out however, that for relay tuning with typical gain and phase margins the overshoot may remain even for b=0. So the paper presents an extension to the set-point weighting approach to eliminate the overshoot completely. Here, in addition to the original modification of proportional action, also the integral action is determined not by the error E but by the difference Wf -W, with Wf generated by a lead-lag filter.
Źródło:
Pomiary Automatyka Robotyka; 2013, 17, 2; 432-435
1427-9126
Pojawia się w:
Pomiary Automatyka Robotyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Central European geostrategic region’s importance for Europe and world
Autorzy:
Kobryński, Robert
Powiązania:
https://bibliotekanauki.pl/articles/121065.pdf
Data publikacji:
2017
Wydawca:
Towarzystwo Wiedzy Obronnej
Tematy:
power
Central European Geostrategic Region
rank-weighting method
potęga
Środkowoeuropejski Region Geostrategiczny
metoda rangowo-wagowa
Opis:
This article presents the concept of a Central European Geostrategic Region (CEGR) covering a belt of states located between the Baltic Sea and the Black Sea, and the Baltic Sea and the Adriatic Sea. This region is important for both NATO and the EU, as some of the countries constitute the Eastern wing (border) of these organisations. On the other hand, the states of this region are significant players for Russian Federation’s external policy, which was visible in the previous years. The Central European Geostrategic Region is, therefore, essential for both Central Eastern Europe’s and whole Europe’s security and is of a major importance for Euro-Atlantic and Eurasian Space. This is why the author presents power of CEGR states calculated with rank-weighting method, which partially reflects regional balance of power. As it results from the calculation, the region is characterised with vast diversity of power distribution between individual political units, which in turn impacts foreign and security policies of the states.
W artykule przedstawiono koncepcję Środkowoeuropejskiego Regionu Geostrategicznego (ŚRG) obejmującego pas państw między przewężeniami bałtycko-czarnomorskim i bałtycko-adriatyckim. Region ten jest istotny z punktu widzenia interesów NATO I UE ponieważ część jego państw stanowi wschodnią flankę (granicę) tych organizacji. Z drugiej strony państwa tego regionu są istotne dla polityki zagranicznej prowadzonej przez Federację Rosyjską, co potwierdzają wydarzenia ostatnich lat. Środkowoeuropejski Region Geostrategiczny odgrywa więc kluczową rolę dla bezpieczeństwa, zarówno Europy Środkowo-Wschodniej jak i całej Europy, a także przestrzeni euroatlantyckiej i euroazjatyckiej. Z tego też względu autor przedstawił potęgę państw ŚRG wyliczoną za pomocą metody rangowo-wagowej, która w pewnym stopniu odzwierciedla regionalny układ sił. Jak wynika z wyliczeń, region ten cechuje się ogromną różnicą w dystrybucji potęgi między poszczególne jednostki polityczne, co z kolei ma wpływ na kształtowanie polityki zagranicznej i bezpieczeństwo tychże państw.
Źródło:
Wiedza Obronna; 2017, 1-2; 13-26
0209-0031
2658-0829
Pojawia się w:
Wiedza Obronna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sample Surveys of Households in Belarus: State and Perspectives
Autorzy:
Bokun, Natalia
Powiązania:
https://bibliotekanauki.pl/articles/465903.pdf
Data publikacji:
2013
Wydawca:
Główny Urząd Statystyczny
Tematy:
sample fraction
territorial probabilistic multistage sampling
weighting
non-responses
private subsidiary plots
Labour Force Survey
Opis:
The main principles, characteristics and problems of three sample surveys of households (HH), conducted by the State Statistics of Belarus are considered: 1) The Household Sample Surveys (on expenses and incomes), 2) Private Subsidiary Plots in rural areas (PSP) and 3) Labour Force Survey (LFS). For each of them the purpose, sampling plan, sample design, data collection mode, the methods of estimation and possible ways to improve the surveys are discussed.
Źródło:
Statistics in Transition new series; 2013, 14, 1; 89-106
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algebraic Riccati equation based Q and R matrices selection algorithm for optimal LQR applied to tracking control of 3rd order magnetic levitation system
Autorzy:
Kumar E, V.
Jerome, J.
Powiązania:
https://bibliotekanauki.pl/articles/140600.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
algebraic Riccatti equation
linear quadratic regulator
magnetic levitation
system
weighting matrices
command following
cost function
Opis:
This paper presents an analytical approach for solving the weighting matrices selection problem of a linear quadratic regulator (LQR) for the trajectory tracking application of a magnetic levitation system. One of the challenging problems in the design of LQR for tracking applications is the choice of Q and R matrices. Conventionally, the weights of a LQR controller are chosen based on a trial and error approach to determine the optimum state feedback controller gains. However, it is often time consuming and tedious to tune the controller gains via a trial and error method. To address this problem, by utilizing the relation between the algebraic Riccati equation (ARE) and the Lagrangian optimization principle, an analytical methodology for selecting the elements of Q and R matrices has been formulated. The novelty of the methodology is the emphasis on the synthesis of time domain design specifications for the formulation of the cost function of LQR, which directly translates the system requirement into a cost function so that the optimal performance can be obtained via a systematic approach. The efficacy of the proposed methodology is tested on the benchmark Quanser magnetic levitation system and a detailed simulation and experimental results are presented. Experimental results prove that the proposed methodology not only provides a systematic way of selecting the weighting matrices but also significantly improves the tracking performance of the system.
Źródło:
Archives of Electrical Engineering; 2016, 65, 1; 151-168
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of active rectifier with LCL filter in the selection process of the weighting factors in finite control set-MPC
Autorzy:
Falkowski, P.
Sikorski, A.
Kulikowski, K.
Korzeniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200718.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
model predictive control (MPC)
active front end converters
inductive-capacitive-inductive (LCL) filter
weighting factors selection
Opis:
One of the main problems of multivariable cost functions in model predictive control is the choice of weighting factors. Two finite control set model predictive control algorithms, applied to the three-phase active rectifier with an LCL filter, are described in the paper. The investigated algorithms, i.e. PCicuc and PCigicuc, implement multivariable approaches applying line (grid) current, capacitor voltage and converter current. The main problem dealt with in the paper is the choice of optimum values of the cost function weighting factors. The values of the factors calculated using the method proposed in the paper are very close to the values represented by the lowest THDi of the line current. Moreover, simulations verifying the equations used in the prediction of controlled values, i.e. line current, capacitor voltage and converter current, are presented. Both simulation and experimental results are presented to verify effectiveness of the investigated control strategies under change of the load (P = 5 kW and 2.5 kW), during transient states, under unbalanced and balanced line voltage.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 1; 51-60
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transformation of geodetic heights between local reference systems – algorithm for rigorous adjustment
Transformacja wysokości geodezyjnych pomiędzy lokalnymi układami odniesienia – algorytm wyrównania ścisłego
Autorzy:
Gargula, Tadeusz
Gawronek, Pelagia
Powiązania:
https://bibliotekanauki.pl/articles/2201682.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Tematy:
1D transformation
post-transformation corrections
transformation weighting
transformacja 1D
korekty post-transformacyjne
wagowanie transformacji
Opis:
The topic of transformations between planar or spatial coordinate systems has been extensively addressed in the literature for years. Usually, researchers present in scientific papers the definitions of iterative algorithms or analytic solutions of 2D or 3D transformations. However, there is a gap in the field with regard to 1D (vertical) transformations. It seems to be quite easy to fill, as it is sufficient to determine one parameter – the vertical shift, i.e. the height difference between two local reference levels. For this purpose, a single (at least) adjustment point is needed, i.e. a surveying benchmark of known heights in both reference systems. However, there is no precisely defined model of rigorous adjustment for a larger number of adjustment points (s > 1). In this paper, the Authors’ have shown several variants of transformations between vertical coordinate systems. These variants include different approaches to weighting the “observations” (heights of adjustment points), such as transformation without weighting and transformation with weighting dependent on the distance between adjustment points (horizontal and vertical distances). Each of the variants was developed in two successive approaches: without transformation corrections and with post-transformation corrections. The research arrived at the latter analogically to the corrections used in planar coordinate transformations (a modification of post-transformation Hausbrandt correction). The analyses made it possible to draw general conclusions determining the relationships between weighting the observations together with applying post-transformation corrections, and the results of height transformation. These findings can become the basis for developers of geodetic computing systems, in terms of the possibility of extending them with a 1D transformation module (in addition to 2D and 3D transformations).
Zagadnienia transformacji pomiędzy układami współrzędnych płaskich bądź współrzędnych przestrzennych od lat znajdują swoje liczne opracowania w literaturze. Badacze w opracowaniach naukowych dokonują definicji zwykle nowych algorytmów iteracyjnych bądź analitycznych rozwiązań transformacji 2D lub 3D. W opracowaniach naukowych istnieje jednak luka naukowa, która dotyczy transformacji 1-wymiarowej (wysokościowej). Zadanie to wydaje się dość proste, ponieważ wystarczy wyznaczyć jeden parametr – przesunięcie pionowe, czyli różnicę wysokości pomiędzy dwoma lokalnymi poziomami odniesienia. W tym celu potrzebny jest jeden (minimalnie) punkt dostosowania, czyli reper o znanej wysokości w obydwu układach. Brakuje jednak jednoznacznie zdefiniowanego modelu wyrównania ścisłego w przypadku większej liczby punktów dostosowania (s > 1). W niniejszym artykule naukowym Autorzy zaprezentowali kilka wariantów transformacji pomiędzy układami współrzędnych wysokościowych. W wariantach tych zastosowano różne podejścia do kwestii wagowania „obserwacji” (wysokości punktów dostosowania), m.in. transformacja bez wagowania oraz transformacja z wagowaniem zależnym od odległości pomiędzy punktami dostosowania (odległości poziomych oraz odległości pionowych). Każdy z wariantów opracowano w dwóch kolejnych podejściach: bez korekt transformacyjnych oraz z korektami post-transformacyjnymi. Korekty post-transformacyjne opracowano analogicznie do korekt stosowanych w transformacji współrzędnych płaskich (modyfikacja korekty post-transformacyjnej Hausbrandta). Rezultaty przeprowadzonych analiz pozwoliły wysnuć wnioski ogólne, określające zależności pomiędzy wagowaniem obserwacji oraz stosowaniem korekt post-transformacyjnych a rezultatem transformacji wysokościowej. Wnioski z przeprowadzonych analiz mogą stać się podstawą dla twórców geodezyjnych systemów obliczeniowych, pod kątem możliwości ich rozszerzenia o moduł transformacji 1D (obok transformacji 2D i 3D).
Źródło:
Geomatics, Landmanagement and Landscape; 2022, 4; 123--135
2300-1496
Pojawia się w:
Geomatics, Landmanagement and Landscape
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neural networks for the generation of sea bed models using airborne lidar bathymetry data
Autorzy:
Kogut, T.
Niemeyer, J.
Bujakiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/145519.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
interpolacja
sieci neuronowe
triangulacja Delaunay
airborne lidar bathymetry
interpolation
neural networks
inverse distance weighting
Delaunay triangulation
Opis:
Various sectors of the economy such as transport and renewable energy have shown great interest in sea bed models. The required measurements are usually carried out by ship-based echo sounding, but this method is quite expensive. A relatively new alternative is data obtained by airborne lidar bathymetry. This study investigates the accuracy of these data, which was obtained in the context of the project ‘Investigation on the use of airborne laser bathymetry in hydrographic surveying’. A comparison to multi-beam echo sounding data shows only small differences in the depths values of the data sets. The IHO requirements of the total horizontal and vertical uncertainty for laser data are met. The second goal of this paper is to compare three spatial interpolation methods, namely Inverse Distance Weighting (IDW), Delaunay Triangulation (TIN), and supervised Artificial Neural Networks (ANN), for the generation of sea bed models. The focus of our investigation is on the amount of required sampling points. This is analyzed by manually reducing the data sets. We found that the three techniques have a similar performance almost independently of the amount of sampling data in our test area. However, ANN are more stable when using a very small subset of points.
Źródło:
Geodesy and Cartography; 2016, 65, 1; 41-53
2080-6736
2300-2581
Pojawia się w:
Geodesy and Cartography
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the moisture change ability of selected crop seeds
Ocena zdolności zmiany wilgotności wybranych nasion roślin uprawnych
Autorzy:
Kornarzyński, K.
Gładyszewska, B.
Powiązania:
https://bibliotekanauki.pl/articles/94000.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
seeds
water collection
capillary-weighting method
moisture content
nasiona
pobieranie wody
metoda kapilarno-wagowa
zawartość wody
Opis:
The objective of the paper was to investigate the moisture change ability of bean, broad bean, pea, lupine, radish, beetroot, winter wheat, maize, cucumber, pumpkin and sunflower seeds. Seeds absorbed water in the system for measurement of the water absorption kinetics with the capillary and weighting method. The research results were presented in the form of plots of the relation of kinetics of the moisture change of seeds in the time for the first and second stage of the process which precedes germination. Moreover, the water content in seeds for the time of the end of the second stage of water absorption was determined and the maximum water absorption speed coefficient and the time of its obtaining was calculated. The water content for the end of the 2nd stage of its collection was the highest for seeds which include a hard caryopsis and for broad bean plant seeds. The maximum water absorption speed coefficient was the highest for seeds with low initial moisture - radish, beetroot, cucumber and pumpkin. The measurement of the water absorption speed with the use of the capillary and weighting method enabled investigation of seeds with a varied size, construction of a seed coat and chemical composition for a long period of time to the moment seedlings were obtained.
Celem pracy było badanie zdolności zmiany wilgotności przez nasiona fasoli, bobu, grochu siewnego, łubinu żółtego, rzodkiewki, buraka ćwikłowego, pszenicy ozimej, pszenżyta, kukurydzy, ogórka, dyni i słonecznika. Nasiona pobierały wodę w układzie do pomiaru kinetyki pobierania wody metodą kapilarno-wagową. Wyniki badań przedstawiono w postaci wykresów zależności kinetyki zmiany wilgotności nasion w czasie dla pierwszej i drugiej fazy procesu poprzedzającej kiełkowanie. Wyznaczono również zawartość wody w nasionach dla czasu końca drugiego etapu pobierania wody oraz maksymalny współczynnik szybkości pobierania wody i czas jego uzyskania. Zawartość wody dla czasu końca II etapu jej pobierania była najwyższa dla nasion zawierających twardą okrywę nasienną oraz dla nasion roślin bobowatych. Maksymalny współczynnik szybkości pobierania wody był najwyższy dla nasion o niskiej wilgotności początkowej - rzodkiewki, buraka, ogórka i dyni. Pomiar szybkości pobierania wody przy wykorzystaniu metody kapilarno-wagowej umożliwił badanie nasion o różnej wielkości, budowie okrywy nasiennej i składzie chemicznym przez długi okres czasu, aż do momentu uzyskania siewek.
Źródło:
Agricultural Engineering; 2017, 21, 1; 59-68
2083-1587
Pojawia się w:
Agricultural Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Market risk, value-at-risk and exponential weighting
Autorzy:
Broll, Udo
Förster, Andreas
Powiązania:
https://bibliotekanauki.pl/articles/2058071.pdf
Data publikacji:
2022-07-11
Wydawca:
Uniwersytet Ekonomiczny w Poznaniu
Tematy:
banks
nfiancial intermediaries
risk management
market risk
exponen tially weighted moving average
weighting scheme
value-at-risk
Opis:
Banks and nfiancial intermediaries are exposed to market risk. The aim of the paper is to explore the implications of legal requirements on market risk valuation. The focus is on the calculation of the permissible weighting factor of the concept of value-at-risk (VaR). When measuring market risk, banks and nfiancial intermediaries may deviate from equally weighting historical data in their value-at-risk calculation and instead use an exponential time series weighting. eTh use of exponential weighting in the value-at-risk calculation is very popular because it takes into account changes in market volatility (immediately) and can therefore quickly adapt to VaR. In less volatile market phases this leads to a reduction in VaR and thus to lower own funds' requirements for banks and nfiancial intermediaries. However, in the exponential weighting a high volatility in the past is quickly forgotten and the VaR can be underestimated. To prevent this banks and nfiancial intermediaries are not completely free to choose a weighting (decay) factor. The exchange rate between Polish zloty and euro is used to estimate the value-at-risk as an example and exceptions to the general legal requirements are also discussed.
Źródło:
Economics and Business Review; 2022, 8, 2; 80-91
2392-1641
Pojawia się w:
Economics and Business Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithm for burden calculation for foundry furnaces using charge materials with an uncertain composition
Algorytm sterowania procesem namiarowania wsadu do pieców odlewniczych z zastosowaniem materiałów o nieprecyzyjnym składzie chemicznym
Autorzy:
Ziółkowski, E.
Powiązania:
https://bibliotekanauki.pl/articles/353302.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
burden calculation
melting optimization
control weighting of charge materials
namiar wsadu
optymalizacja topnienia
kontrola wagi materiałów wsadowych
Opis:
Calculation of charge burden to foundry furnaces by computing the proportions of particular charge materials is a most complicated task as a variety of technological aspects have to be considered. For practical and economic reasons, this problem is typically solved using computer-based optimisation methods, the main criterion being the optimal amount of charge materials related to the lowest costs of the burden. The problem is further complicated when the chemical composition of the charge materials is not accurately defined. So far the calculations of the charge burden were performed in order to work out the detailed melt procedure, which was to be modified and corrected by the trial and error method in subsequent melt processes. An algorithm has been developed for use in calculating the charge burden depending on the target chemical composition of the casting alloy. Of particular importance is the application of the algorithm when the process conditions are changeable.
Wyznaczanie namiaru wsadu do pieców odlewniczych, metodą obliczeń udziału poszczególnych materiałów wsadowych jest zadaniem złożonym z powodu znacznej liczby założeń technologicznych. Ze względów merytorycznych, praktycznych i ekonomicznych dąży się takiego zadania za pomocą komputerowych metod optymalizacyjnych, w których uwzględnia się kryterium optymalnej ilości materiałów przy najniższym koszcie całkowitym namiaru. Problem złożoności zadań jest tym większy im bardziej skład chemiczny materiałów wsadowych jest nieprecyzyjny. Dotychczas obliczanie namiaru wsadu było zazwyczaj realizowane wyłącznie na potrzeby przygotowania instrukcji wytopu, którą korygowano wynikami uzyskanymi metodą prób i błędów w kolejnych wytopach. W artykule przedstawiono algorytm wyznaczania namiaru wsadu zestawianego w sposób zależny od zapotrzebowania na określony skład chemiczny produkowanego stopu odlewniczego. Szczególną uwagę zwrócono na możliwość efektywnego działania algorytmu w zmiennych warunkach technologicznych.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 3; 887-889
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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