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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A study of two variables Legendre polynomials

Khan, Mumtaz Ahmad, Singh, Mukesh Pal 25 September 2017 (has links)
The present paper deals with a study of a two variable polynomial Pn(x) analogues to the Legendre polynomial Pn(x). The paper contains differential recurrence relations, a partial differential equation, double generating functions, double and triple hypergeometric forms, a special property and a bilinear double generating function for the newly defined polynomials Pn,k(x, y).
12

On a general class of Polynomials Ln (x, y) of two variables suggested by the Polynomials Ln (x, y) of Ragab and Ln (x) of Prabhakar and Rekha

Khan, Mumtaz Ahmad, Ahmad, Khvurshed 25 September 2017 (has links)
No description available.
13

Combinatorial problems related to sequences with repeated entries

Archibald, Margaret Lyn 15 November 2006 (has links)
Student Number : 9708525G - PhD thesis - School of Mathematics - Faculty of Science / Sequences of numbers have important applications in the field of Computer Science. As a result they have become increasingly regarded in Mathematics, since analysis can be instrumental in investigating algorithms. Three concepts are discussed in this thesis, all of which are concerned with ‘words’ or ‘sequences’ of natural numbers where repeated letters are allowed: • The number of distinct values in a sequence with geometric distri- bution In Part I, a sample which is geometrically distributed is considered, with the objective of counting how many different letters occur at least once in the sample. It is concluded that the number of distinct letters grows like log n as n → ∞. This is then generalised to the question of how many letters occur at least b times in a word. • The position of the maximum (and/or minimum) in a sequence with geometric distribution Part II involves many variations on the central theme which addresses the question: “What is the probability that the maximum in a geometrically distributed sample occurs in the first d letters of a word of length n?” (assuming d ≤ n). Initially, d is considered fixed, but in later chapters d is allowed to grow with n. It is found that for 1 ≤ d = o(n), the results are the same as when d is fixed. • The average depth of a key in a binary search tree formed from a sequence with repeated entries Lastly, in Part III, random sequences are examined where repeated letters are allowed. First, the average left-going depth of the first one is found, and later the right-going path to the first r if the alphabet is {1, . . . , r} is examined. The final chapter uses a merge (or ‘shuffle’) operator to obtain the average depth of an arbitrary node, which can be expressed in terms of the left-going and right-going depths.
14

Dinâmica adaptativa, genealogias e testes estatísticos de neutralidade em evolução molecular / Adaptive dynamics, Genealogies and statistical tests of neutrality in molecular evolution

Maia, Leonardo Paulo 24 August 2004 (has links)
Esta tese aborda diversos temas em evolução molecular, usando extensivamente o formalismo de funções geratrizes para obter resultados analíticos sempre que possível. Em primeiro lugar, apresenta-se a solução exata para o comportamento dinâmico de uma população infinita de seqüências infinitamente longas (não há mutações reversas) evoluindo sob a ação de mutações deletérias em um relevo adaptativo multiplicativo ou truncado. Além disso, foi estudado o comportamento de uma população submetida a sucessivas diluições de intensidades arbitrárias, como ocorre em alguns protocolos de evolução experimental. Foram obtidas expressões matemáticas que, em princípio, podem ser úteis na caracterização de populações reais de microorganismos. Demonstrou-se também que um processo estocástico de ramificação multidimensional generalizado é uma excelente ferramenta para analisar numericamente os efeitos da degeneração mutacional (especificamente, de um fenômeno denominado catraca de Muller) em populações sob variadas condições de crescimento exponencial. Finalmente, simulações foram extensivamente utilizadas para analisar a história evolutiva de populações finitas e averiguar a possibilidade de certas grandezas, como certas medidas da topologia de árvores genealógicas, serem empregadas na elaboração de testes estatísticos capazes de detectar as marcas deixadas pela seleção natural. / This thesis discusses some topics of molecular evolution, extensively using generating function methods to find analytical results whenever possible. In first place, it gives the exact solution for the dynamics of an infinite population of infinitely long sequences (no back mutations) evolving under the action of deleterious mutations on either multiplicative or truncated fitness landscapes. In addition, the behavior of a population subject to successive dilutions of arbitrary intensity, just like some experimental evolution protocols, is found. The mathematical expressions, in principle, may prove useful in characterizing real populations of microor¬ganisms. It was also demonstrated that a generalized multidimensional branching process is a nice tool in numerically studying mutational degeneration effects (specifically a pheno¬menon called Muller\'s ratchet) in populations under a wide variety of exponential growth settings. Finally, the evolutionary history of finite populations was studied by simulations to probe the viability of certain statistic, like some topological measures in genealogical trees, being incorporated in statistical tests to detect the fingerprints of natural selection.
15

Counting Vertices in Isohedral Tilings

Choi, John 31 May 2012 (has links)
An isohedral tiling is a tiling of congruent polygons that are also transitive, which is to say the configuration of degrees of vertices around each face is identical. Regular tessellations, or tilings of congruent regular polygons, are a special case of isohedral tilings. Viewing these tilings as graphs in planes, both Euclidean and non-Euclidean, it is possible to pose various problems of enumeration on the respective graphs. In this paper, we investigate some near-regular isohedral tilings of triangles and quadrilaterals in the hyperbolic plane. For these tilings we enumerate vertices as classified by number of edges in the shortest path to a given origin, by combinatorially deriving their respective generating functions.
16

Generating Functions And Their Applications

Bilgin, Begul 01 August 2010 (has links) (PDF)
Generating functions are important tools that are used in many areas of mathematics and especially statistics. Besides analyzing the general structure of sequences and their asymptotic behavior / these functions, which can be roughly thought as the transformation of sequences into functions, are also used effciently to solve combinatorial problems. In this thesis, the effects of the transformations of generating functions on their corresponding sequences and the effects of the change in sequences on the generating functions are examined. With these knowledge, the generating functions for the resulting sequence of some combinatorial problems such as number of partitions, number of involutions, Fibonacci numbers and Catalan numbers are found. Moreover, some mathematical identities are proved by using generating functions. The sequences are the bases of especially symmetric key cryptosystems in cryptography. It is seen that by using generating functions, linear complexities and periods of sequences generated by constant coeffcient linear homogeneous recursions, which are used in linear feedback shift register (LFSR) based stream ciphers, can be calculated. Hence studying generating functions leads to have a better understanding in them. Therefore, besides combinatorial problems, such recursions are also examined and the results are used to observe the linear complexity and the period of LFSR&rsquo / s combined in different ways to generate &ldquo / better&rdquo / system of stream cipher.
17

A study of modified hermite polynomials

Khan, Mumtaz Ahmad, Khan, Abdul Hakim, Ahmad, Naeem 25 September 2017 (has links)
The present paper is a study of modied Hermitepolynomials Hn(x; a) which reduces to Hermite polynomialsHn(x) for a = e.
18

Photovoltaic Systems: Forecasting for Demand Response Management and Environmental Modelling to Design Accelerated Aging Tests

January 2017 (has links)
abstract: Distributed Renewable energy generators are now contributing a significant amount of energy into the energy grid. Consequently, reliability adequacy of such energy generators will depend on making accurate forecasts of energy produced by them. Power outputs of Solar PV systems depend on the stochastic variation of environmental factors (solar irradiance, ambient temperature & wind speed) and random mechanical failures/repairs. Monte Carlo Simulation which is typically used to model such problems becomes too computationally intensive leading to simplifying state-space assumptions. Multi-state models for power system reliability offer a higher flexibility in providing a description of system state evolution and an accurate representation of probability. In this study, Universal Generating Functions (UGF) were used to solve such combinatorial problems. 8 grid connected Solar PV systems were analyzed with a combined capacity of about 5MW located in a hot-dry climate (Arizona) and accuracy of 98% was achieved when validated with real-time data. An analytics framework is provided to grid operators and utilities to effectively forecast energy produced by distributed energy assets and in turn, develop strategies for effective Demand Response in times of increased share of renewable distributed energy assets in the grid. Second part of this thesis extends the environmental modelling approach to develop an aging test to be run in conjunction with an accelerated test of Solar PV modules. Accelerated Lifetime Testing procedures in the industry are used to determine the dominant failure modes which the product undergoes in the field, as well as predict the lifetime of the product. UV stressor is one of the ten stressors which a PV module undergoes in the field. UV exposure causes browning of modules leading to drop in Short Circuit Current. This thesis presents an environmental modelling approach for the hot-dry climate and extends it to develop an aging test methodology. This along with the accelerated tests would help achieve the goal of correlating field failures with accelerated tests and obtain acceleration factor. This knowledge would help predict PV module degradation in the field within 30% of the actual value and help in knowing the PV module lifetime accurately. / Dissertation/Thesis / Masters Thesis Industrial Engineering 2017
19

Dinâmica adaptativa, genealogias e testes estatísticos de neutralidade em evolução molecular / Adaptive dynamics, Genealogies and statistical tests of neutrality in molecular evolution

Leonardo Paulo Maia 24 August 2004 (has links)
Esta tese aborda diversos temas em evolução molecular, usando extensivamente o formalismo de funções geratrizes para obter resultados analíticos sempre que possível. Em primeiro lugar, apresenta-se a solução exata para o comportamento dinâmico de uma população infinita de seqüências infinitamente longas (não há mutações reversas) evoluindo sob a ação de mutações deletérias em um relevo adaptativo multiplicativo ou truncado. Além disso, foi estudado o comportamento de uma população submetida a sucessivas diluições de intensidades arbitrárias, como ocorre em alguns protocolos de evolução experimental. Foram obtidas expressões matemáticas que, em princípio, podem ser úteis na caracterização de populações reais de microorganismos. Demonstrou-se também que um processo estocástico de ramificação multidimensional generalizado é uma excelente ferramenta para analisar numericamente os efeitos da degeneração mutacional (especificamente, de um fenômeno denominado catraca de Muller) em populações sob variadas condições de crescimento exponencial. Finalmente, simulações foram extensivamente utilizadas para analisar a história evolutiva de populações finitas e averiguar a possibilidade de certas grandezas, como certas medidas da topologia de árvores genealógicas, serem empregadas na elaboração de testes estatísticos capazes de detectar as marcas deixadas pela seleção natural. / This thesis discusses some topics of molecular evolution, extensively using generating function methods to find analytical results whenever possible. In first place, it gives the exact solution for the dynamics of an infinite population of infinitely long sequences (no back mutations) evolving under the action of deleterious mutations on either multiplicative or truncated fitness landscapes. In addition, the behavior of a population subject to successive dilutions of arbitrary intensity, just like some experimental evolution protocols, is found. The mathematical expressions, in principle, may prove useful in characterizing real populations of microor¬ganisms. It was also demonstrated that a generalized multidimensional branching process is a nice tool in numerically studying mutational degeneration effects (specifically a pheno¬menon called Muller\'s ratchet) in populations under a wide variety of exponential growth settings. Finally, the evolutionary history of finite populations was studied by simulations to probe the viability of certain statistic, like some topological measures in genealogical trees, being incorporated in statistical tests to detect the fingerprints of natural selection.
20

Introdução ao estudo de funções geradoras / Introduction to the study of generating functions

Rodrigues, Júlio César Prado Souza 06 March 2018 (has links)
Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-06-11T14:22:11Z No. of bitstreams: 2 Dissertação - Júlio César Prado Souza Rodrigues - 2018.pdf: 2605714 bytes, checksum: 66d166b7f935c98e7035a80c4ad2106b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-06-11T15:51:55Z (GMT) No. of bitstreams: 2 Dissertação - Júlio César Prado Souza Rodrigues - 2018.pdf: 2605714 bytes, checksum: 66d166b7f935c98e7035a80c4ad2106b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-11T15:51:55Z (GMT). No. of bitstreams: 2 Dissertação - Júlio César Prado Souza Rodrigues - 2018.pdf: 2605714 bytes, checksum: 66d166b7f935c98e7035a80c4ad2106b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work, our goal is to present some combinatorial problems that can be solved using the Generating Functions and also to show that this study can contribute to future research as well as to new methodological possibilities for the teaching of Mathematics. / Neste trabalho, temos como objetivo apresentar alguns problemas combinatórios que podem ser solucionados utilizando as Funções Geradoras e, também, mostrar que este estudo pode contribuir tanto para futuras pesquisas quanto para novas possibilidades metodológicas para o ensino da Matemática.

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