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Tytuł:
19th-century real analysis, forward and backward
Autorzy:
Bair, Jacques
Blaszczyk, Piotr
Heinig, Peter
Kanovei, Vladimir
Katz, Mikhail
Powiązania:
https://bibliotekanauki.pl/articles/2012067.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
butterfly model
continuity
infinitesimals
\emph{limite}
standard part
variable quantity
Cauchy
de Prony
Opis:
19th-century real analysis received a major impetus from Cauchy's work. Cauchy mentions variable quantities, limits, and infinitesimals, but the meaning he attached to these terms is not identical to their modern meaning. Some Cauchy historians work in a conceptual scheme dominated by an assumption of a teleological nature of the evolution of real analysis toward a preordained outcome. Thus, Gilain and Siegmund-Schultze assume that references to limite in Cauchy's work necessarily imply that Cauchy was working with an Archimedean continuum, whereas infinitesimals were merely a convenient figure of speech, for which Cauchy had in mind a complete justification in terms of Archimedean limits. However, there is another formalization of Cauchy's procedures exploiting his limite, more consistent with Cauchy's ubiquitous use of infinitesimals, in terms of the standard part principle of modern infinitesimal analysis. We challenge a misconception according to which Cauchy was allegedly forced to teach infinitesimals at the Ecole Polytechnique. We show that the debate there concerned mainly the issue of rigor, a separate one from infinitesimals. A critique of Cauchy's approach by his contemporary de Prony sheds light on the meaning of rigor to Cauchy and his contemporaries. An attentive reading of Cauchy's work challenges received views on Cauchy's role in the history of analysis and indicates that he was a pioneer of infinitesimal techniques as much as a harbinger of the Epsilontik.
Dziewiętnastowieczna rzeczywista analiza otrzymała duży impuls w pracach Cauchy'ego. Cauchy posługuje się pojęciem zmiennej, granicy i nieskończenie małej, ale znaczenie, które wiąże z tymi terminami jest inne niż u jemu współczesnych autorów. Niektórzy historycy Cauchy'ego utrzymują schemat pojęciowy zdominowany przez założenie teleologicznej natury ewolucji rzeczywistej analizy w kierunku z góry ustalonej konstrukcji. Zatem Gilain i Siegmund-Schultze zakładają, że odniesienia do granicy (limite) w pracy Cauchy'ego niekoniecznie oznaczają, że Cauchy posługiwał się kontinuum Archimedesa, podczas gdy nieskończenie małe były jedynie wygodną figurą retoryczną, dla której Cauchy miał na myśli pełne uzasadnienie w kategoriach granic Archimedesa. Istnieje jednak inna formalizacja procedur Cauchy'ego wykorzystujących jego granice(limite), bardziej spójna z wszechobecnym użyciem nieskończenie małych Cauchy'ego, w kategoriach standardowej części zasady nowoczesnej analizy nieskończenie małej. Podważamy błędne przekonanie, zgodnie z którym Cauchy został rzekomo zmuszony do nauczania nieskończenie małych w Ecole Polytechnique. Pokazujemy, że debata dotyczyła głównie kwestii ścisłości, oddzielnego od nieskończenie małych. Krytyka podejścia Cauchy'ego przez jego współczesnego de Prony rzuca światło na znaczenie ścisłości dla Cauchy'ego i jego współczesnych. Uważna lektura wyzwań Cauchy'ego spotkała się z poglądem na rolę Cauchy'ego w historii analizy i wskazuje, że był on pionierem nieskończenie małych technik, podobnie jak zapowiedzią Epsilontiki.
Źródło:
Antiquitates Mathematicae; 2019, 13; 19-49
1898-5203
2353-8813
Pojawia się w:
Antiquitates Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
1D and 2D finite-difference operators for periodic functions on arbitrary mesh
Autorzy:
Sobczyk, Tadeusz Jan
Powiązania:
https://bibliotekanauki.pl/articles/2042801.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
arbitrary meshes
finite-difference operators
partial finite difference operators
periodic function
two-variable periodic functions
Opis:
This paper presents novel discrete differential operators for periodic functions of one- and two-variables, which relate the values of the derivatives to the values of the function itself for a set of arbitrarily chosen points over the function’s area. It is very characteristic, that the values of the derivatives at each point depend on the function values at all points in that area. Such operators allow one to easily create finite-difference equations for boundaryvalue problems. The operators are addressed especially to nonlinear differential equations.
Źródło:
Archives of Electrical Engineering; 2022, 71, 1; 265-275
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Better Estimator of Population Mean with Power Transformation Based on Ranked Set Sampling
Autorzy:
Mehta (Ranka), Nitu
Mandowara, V. L.
Powiązania:
https://bibliotekanauki.pl/articles/466002.pdf
Data publikacji:
2012
Wydawca:
Główny Urząd Statystyczny
Tematy:
ranked set sampling
ratio estimator
power transformation estimator auxiliary variable
Opis:
Ranked set sampling (RSS) was first suggested by McIntyre (1952) to increase the efficiency of estimate of the population mean. It has been shown that this method is highly beneficial to the estimation based on simple random sampling (SRS). There has been considerable development and many modifications were done on this method. This paper presents a modified ratio estimator using prior value of coefficient of kurtosis of an auxiliary variable x, with the intention to improve the efficiency of ratio estimator in ranked set sampling. The first order approximation to the bias and mean square error (MSE) of the proposed estimator are obtained. A generalized version of the suggested estimator by applying the Power transformation is also presented.
Źródło:
Statistics in Transition new series; 2012, 13, 3; 551-558
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A calibrated synthetic estimator for small area estimation
Autorzy:
Iseh, Matthew Joshua
Enang, Ekaette Inyang
Powiązania:
https://bibliotekanauki.pl/articles/1827531.pdf
Data publikacji:
2021-09-06
Wydawca:
Główny Urząd Statystyczny
Tematy:
auxiliary variable
calibration estimation
simulation
synthetic estimation
Opis:
Synthetic estimators are known to produce estimates of population mean in areas where no sampled data are available, but such estimates are usually highly biased with invalid confidence statements. This paper presents a calibrated synthetic estimator of the population mean which addresses these problematic issues. Two known special cases of this estimator were obtained in the form of combined ratio and combined regression synthetic estimators, using selected tuning parameters under stratified sampling. In result, their biases and variance estimators were derived. The empirical demonstration of the usage involving the proposed calibrated estimators shows that they provide better estimates of the population mean than the existing estimators discussed in this study. In particular, the estimators were examined through simulation under three distributional assumptions, namely the normal, gamma and exponential distributions. The results show that they provide estimates of the mean displaying less relative bias and greater efficiency. Moreover, they prove more consistent than the existing classical synthetic estimator. The further evaluation carried out using the coefficient of variation provides additional confirmation of the calibrated estimator's advantage over the existing ones in relation to small area estimation.
Źródło:
Statistics in Transition new series; 2021, 22, 3; 15-30
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Class of Regression Type Estimators in Survey Sampling
Autorzy:
Misra, Govind Charan
Yadav, Subhash Kumar
Shukla, Alok Kumar
Powiązania:
https://bibliotekanauki.pl/articles/465942.pdf
Data publikacji:
2011
Wydawca:
Główny Urząd Statystyczny
Tematy:
Auxiliary variable
Mean Squared Error
Ratio estimator
Regression type estimators
Opis:
A class of linear regression models has been proposed for the estimation of population mean and total when information regarding auxiliary variate is available in survey sampling using regression method of estimation by introducing a new auxiliary variable z, which may also be a function of the auxiliary variable x. The proposed model leads to reduction in mean squared error as compared to ordinary regression method of estimation. The improvement has been demonstrated over ordinary regression estimator and also on ratio estimator with the help of an empirical example.
Źródło:
Statistics in Transition new series; 2011, 12, 3; 579-586
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A concept of determining the relation between load and wear of tribological systems of ship main selfignition engines by using probabilistic approach
Autorzy:
Girtler, J.
Powiązania:
https://bibliotekanauki.pl/articles/258580.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
combustion engine load
probability
stochastic process
self-ignition engine
random variable
statistical relation
stochastic relation
Opis:
This paper presents a proposal of simultaneous consideration of load and wear associated with it , of tribological systems of ship main engines (intended for ship propulsion) . Based on results of investigations it was assumed that both the load Q (i.e. a cause of wear ) and the wear Z (i.e. an effect of load occurrence) considered in a given time t (0 ≤ t ≤ tn) are random variables Qt and Zt ,respectively. There was characterized operational principle of ship main engines in definite external conditions (WZ) as well as consequences of excessive load of engines. Three hypotheses highlighting relations existing between load and wear of the above mentioned systems, have been proposed. The first of them deals with explanation of stochastic relation between load and wear, the second highlights why it is possible to assume that the load Qt and the wear Zt are positively correlated , and the third – why it is possible to assume that coefficient of correlation between Qt and Zt may be taken close to one.
Źródło:
Polish Maritime Research; 2018, 4; 130-138
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Context-Based Approach to Linguistic Hedges
Autorzy:
De Cock, M.
Kerre, E. E.
Powiązania:
https://bibliotekanauki.pl/articles/908039.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
informatyka
L-fuzzy modifier
L-fuzzy relation
resemblance relation
linguistic hedge
linguistic variable
Opis:
We present a framework of L-fuzzy modifiers for L being a complete lattice. They are used to model linguistic hedges that act on linguistic terms represented by L-fuzzy sets. In the modelling process the context is taken into account by means of L-fuzzy relations, endowing the L-fuzzy modifiers with a clear inherent semantics. To our knowledge, these L-fuzzy modifiers are the first ones proposed that are suitable to perform this representation task for a lattice L different from the unit interval. In the latter case they undoubtedly outperform the traditional representations, such as powering and shifting hedges, from the semantical point of view.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 3; 371-382
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A continuum description of failure waves
Autorzy:
Said, H.
Glimm, J.
Powiązania:
https://bibliotekanauki.pl/articles/279743.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
brittle fracture
failure wave
internal variable
dissipative systems
variational principle
Opis:
Shattering of a brittle material such as glass occurs dynamically through a propagating failure wave, which however, can not be assigned to any of the classical wave. In this paper, we build a thermodynamically consistent theory based on the idea that a failure wave is analogous to a deflagration wave. Our theory admits, as special cases, the classical models of Feng and Clifton. Two fundamental thermodynamic functions form the basis of our theory. This approach allows for the construction of a new variational principle and a Lagrangian formulation. Finally, the theory is linearized to interpret specific experimental observations.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 3; 657-674
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A fixed point method in dynamic processes for a class of elastic-viscoplastic materials
Autorzy:
Amassad, A.
Powiązania:
https://bibliotekanauki.pl/articles/1294435.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
viscoplasticity
dynamic processes
Galerkin method
fixed point
internal state variable
Opis:
Two problems are considered describing dynamic processes for a class of rate-type elastic-viscoplastic materials with or without internal state variable. The existence and uniqueness of the solution is proved using classical results of linear elasticity theory together with a fixed point method.
Źródło:
Annales Polonici Mathematici; 1998, 68, 3; 237-247
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A geomorphodiversity map of the Soutpansberg Range, South Africa
Autorzy:
Kori, Edmore
Onyango Odhiambo, Beneah Daniel
Chikoore, Hector
Powiązania:
https://bibliotekanauki.pl/articles/294524.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Geomorfologów Polskich
Tematy:
geomorphological diversity
Soutpansberg
variable
geodiversity
geomorphology
Opis:
Within the emerging broad science of geodiversity, geomorphological diversity (geomorphodiversity) assesses the form of surface features of a place or region. This paper uses SRTM data and GIS techniques to assess geomorphological diversity of the Soutpansberg range, in Limpopo Province, South Africa. Suitable factors to assess geomorphological diversity were identified as geology, slope position, soil erodibility, landform position, relative heights, insolation, hydrography and ruggedness. Each factor was normalised to five classes by applying natural breaks. All the eight factors were weighted before overlaying. The weighting reveal that respectively, geology, slope and soils carry more weight. Ruggedness, relative height and insolation carry the least weight, in that order. The final geomorphodiversity map reveals that almost half of the Soutpansberg range has high to very high geomorphological diversity. We conclude that factor specific research can add more information to geomorphodiversity research and education.
Źródło:
Landform Analysis; 2019, 38; 13-24
1429-799X
Pojawia się w:
Landform Analysis
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Lagrangian Finite Element Analysis of Gravity Waves in Water of Variable Depth
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241185.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
gravity water wave
variable water depth
transient problem
Lagrangian formulation
finite element method
Opis:
The paper is concerned with the problem of gravitational wave propagation in water of variable depth. The problem is formulated in the Lagrangian description, and the ensuing equations are solved numerically by a finite element method. In computations a convecting mesh that follows the material fluid particles is used. As illustrations, results of numerical simulations carried out for plane gravity waves propagating over bottoms of simple geometry are presented. For parameters typical of a laboratory flume, the transformation of a transient wave, generated by a single movement of a piston-like wave maker, is investigated. The results show the evolution of the free-surface elevation, displaying steepening of the wave over sloping beds and its gradual attenuation in regions of uniform depth.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2009, 56, 1-2; 43-61
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mode-III crack with variable surface effects
Autorzy:
Wang, X.
Schiavone, P.
Powiązania:
https://bibliotekanauki.pl/articles/282009.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
surface elasticity
variable surface moduli
mode-III crack
Cauchy singular integro-differential equation
Opis:
We study the contribution of variable surface effects to the antiplane deformation of a linearly elastic material with a mode-III crack. The surface elasticity is incorporated using a modified version of the continuum based surface/interface model of Gurtin and Murdoch. In our discussion, the surface moduli are not constant but vary along the crack surfaces. Using Green’s function method, the problem is reduced to a single first-order Cauchy singular integro-differential equation, which is solved numerically using Chebyshev polynomials and a collocation method. Our results indicate that the gradient of the surface shear modulus exerts a significant influence on the crack opening displacement and on the singular stress field at the crack tips.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1319-1327
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A model for the inverse 1-median problem on trees under uncertain costs
Autorzy:
Nguyen, K. T.
Chi, N. T. L.
Powiązania:
https://bibliotekanauki.pl/articles/254814.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
location problem
uncertain variable
inverse optimization problem
tree
Opis:
We consider the problem of justifying vertex weights of a tree under uncertain costs so that a prespecified vertex become optimal and the total cost should be optimal in the uncertainty scenario. We propose a model which delivers the information about the optimal cost which respect to each confidence level α ∈ [0,1]. To obtain this goal, we first define an uncertain variable with respect to the minimum cost in each confidence level. If all costs are independently linear distributed, we present the inverse distribution function of this uncertain variable in [formula]time, where n is the number of vertices in the tree.
Źródło:
Opuscula Mathematica; 2016, 36, 4; 513-523
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Multivariate Technique to Develop Hybrid Water Quality Index of the Bengawan Solo River, Indonesia
Autorzy:
Lusiana, Evellin Dewi
Mahmudi, Mohammad
Hutahaean, Sarah Mega
Darmawan, Arief
Buwono, Nanik Retno
Arsad, Sulastri
Musa, Muhammad
Powiązania:
https://bibliotekanauki.pl/articles/2026733.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
principal component analysis
WQI
water quality index
variable selection
water quality assessment
Opis:
Surface water resource, such as river, is constantly contaminated by domestic and industrial pollutants. In order to properly manage the water resource, a composite index for water quality assessment, such as water quality index (WQI), has been designed to monitor and evaluate the properties of surface water. However, this index is quite subjective in terms of determination of relative weights. A principal component analysis (PCA) can be used to reduce the dimension and subjectivity of water quality variables. The purpose of this study was to implement the use of hybrid PCA and WQI methods to assess and monitor the water quality of the Bengawan Solo River, which is located in Java Island, Indonesia. The result suggested that COD, BOD, TSS, TDS, nitrate, nitrite, and ammonia were the main factors that determine water quality of the Bengawan Solo River. Furthermore, it was revealed that most samples from the river showed water quality status as slightly polluted. In addition to this, the seasonal variation of the PCWI values indicated a significant increase of water pollution in the Bengawan Solo River per year.
Źródło:
Journal of Ecological Engineering; 2022, 23, 2; 123-131
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new form of Boussinesq equations for long waves in water of non-uniform depth
Autorzy:
Szmidt, J.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/201637.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
long wave
Boussinesq equation
wave transformation
variable water depth
Opis:
The paper describes the non-linear transformation of long waves in shallow water of variable depth. Governing equations of the problem are derived under the assumption that the non-viscous fluid is incompressible and the fluid flow is a rotation free. A new form of Boussinesq-type equations is derived employing a power series expansion of the fluid velocity components with respect to the water depth. These non-linear partial differential equations correspond to the conservation of mass and momentum. In order to find the dispersion characteristic of the description, a linear approximation of these equations is derived. A second order approximation of the governing equations is applied to study a time dependent transformation of waves in a rectangular basin of water of variable depth. Such a case corresponds to a spatially periodic problem of sea waves approaching a near-shore zone. In order to overcome difficulties in integrating these equations, the finite difference method is applied to transform them into a set of non-linear ordinary differential equations with respect to the time variable. This final set of these equations is integrated numerically by employing the fourth order Runge - Kutta method.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 3; 631-643
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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