Dissertations / Theses on the topic 'SHANNON ENTROPHY'
To see the other types of publications on this topic, follow the link: SHANNON ENTROPHY.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'SHANNON ENTROPHY.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Pougaza, Doriano-Boris. "Utilisation de la notion de copule en tomographie." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00684637.
Full textAbstract:
Cette thèse porte sur le lien entre la tomographie et la notion de copule. La tomographie à rayons X consiste à (re)construire la structure cachée d'un objet (une densité de matière, la distribution d'une quantité physique, ou une densité de loi conjointe) à partir de certaines données obtenues ou mesurées de l'objet (les projections, les radiographies, les densités marginales). Le lien entre les mesures et l'objet se modélise mathématiquement par la Transformée à Rayons X ou la Transformée de Radon. Par exemple, dans les problèmes d'imagerie en géométrie parallèle, lorsqu'on a seulement deux projections à deux angles de 0 et pi/2 (horizontale et verticale), le problème peut être identifié comme un autre problème très important en mathématique qui est la détermination d'une densité conjointe à partir de ses marginales. En se limitant à deux projections, les deux problèmes sont des problèmes mal posés au sens de Hadamard. Il faut alors ajouter de l'information a priori, ou bien des contraintes supplémentaires. L'apport principal de cette thèse est l'utilisation des critères de plusieurs entropies (Rényi, Tsallis, Burg, Shannon) permettant d'aboutir à une solution régularisée. Ce travail couvre alors différents domaines. Les aspects mathématiques de la tomographie via l'élément fondamental qui est la transformée de Radon. En probabilité sur la recherche d'une loi conjointe connaissant ses lois marginales d'où la notion de ''copule'' via le théorème de Sklar. Avec seulement deux projections, ce problème est extrêmement difficile. Mais en assimilant les deux projections (normalisées) aux densités marginales et l'image à reconstruire à une densité de probabilité, le lien se fait et les deux problèmes sont équivalents et peuvent se transposer dans le cadre statistique. Pour caractériser toutes les images possibles à reconstruire on a choisi alors l'outil de la théorie de probabilité, c'est-à-dire les copules. Et pour faire notre choix parmi les copules ou les images nous avons imposé le critère d'information a priori qui se base sur différentes entropies. L'entropie est une quantité scientifique importante car elle est utilisée dans divers domaines (en Thermodynamique, en théorie de l'information, etc). Ainsi, en utilisant par exemple l'entropie de Rényi nous avons découvert de nouvelles classes de copules. Cette thèse apporte de nouvelles contributions à l'imagerie, par l'interaction entre les domaines qui sont la tomographie et la théorie des probabilités et statistiques.
2
Wells, Michael John Christopher. "Curious Omosa : Does player satisfaction increase the more they learn about their game environment?" Thesis, Umeå universitet, Institutionen för psykologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-175281.
Full textAbstract:
The science of curiosity is not fully understood, yet it seems to be a key component of nature which drives both humans and animals to seek out new information. Humans actively seek out to solve problems for the sake of solving them, with evidence suggesting that the seeking and obtaining of new knowledge is itself inherently rewarding. This study uses new methods to collect data to investigate how humans react when presented with novel environments and a problem to solve. Information gain was tracked using Shannon’s entropy, a measure of how effective a communication is at communicating its message across. The study investigates if participants feelings of satisfaction will increase the more information they receive, as measured by a change in Shannon’s entropy. A total of 44 participants with complete data were recruited accross two conditions A and B, with A containing a complete knowlege graph to determine what knowledge is gained through interactions with the environment and B containing more uncertainty so that the participant can be observed building their own knowledge-graph. Participants entered a virtual enviroment named Omosa where they were told about a mystery involving the deaths of herbivores on the island. Participants were given free reign to explore and investigate for a minimum 6 minutes. In increments of 90s, participants were asked questions about what they thought was killing the herd and how confident they were of their answer. After 6 minutes final questions were presented collecting player satisfaction and trait curiosity. Additional meta-data including trajectory and interactions were also collected. No significant results were gleaned due to high drop out and incomplete data. Methodology could be altered in future renditions to increase participation and reduce drop out.Vetenskapen om nyfikenhet förstås inte helt, men det verkar vara en nyckelkomponent i naturen som driver både människor och djur att söka ny information. Människor försöker aktivt lösa problem för att lösa dem, med bevis som tyder på att att söka och få ny kunskap i sig är givande i sig. Denna studie använder nya metoder för att samla in data för att undersöka hur människor reagerar när de presenteras för nya miljöer och ett problem att lösa. Informationsvinster spårades med hjälp av Shannons entropi, ett mått på hur effektiv en kommunikation är för att kommunicera sitt budskap. Studien undersöker om deltagarnas känslor av tillfredsställelse kommer att öka mer information de får, mätt med en förändring i Shannons entropi. Totalt rekryterades 44 deltagare med fullständig data enligt två villkor A och B, där A innehöll en fullständig kunskapsgraf för att bestämma vilken kunskap som erhålls genom interaktioner med miljön och B som innehåller mer osäkerhet så att deltagaren kan observeras bygga sin egen kunskaps grafen. Deltagarna gick in i ett virtuellt miljö med namnet Omosa där de fick höra om ett mysterium som involverade djur av växtätare på ön. Deltagarna fick fri tid att utforska och undersöka i minst 6 minuter. I steg från 90-talet ställdes deltagarna frågor om vad de trodde dödade besättningen och hur säkra de var på svaret. Efter 6 minuter presenterades de sista frågorna för att samla spelarnas nöjdhet och dragkänslighet. Ytterligare metadata inklusive bana och interaktioner samlades också in. Inga signifikanta resultat samlades in på grund av högt bortfall och ofullständig data. Metodik kan ändras i framtida versioner för att öka deltagandet och minska bortfallet.
3
Silva, Danilo Antonio da [UNESP]. "Síntese e caracterização de partículas de poli(álcool vinílico) utilizadas em aplicações biomédicas: contribuição da análise fractal e entropia de Shannon." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87540.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:22:55Z (GMT). No. of bitstreams: 0
Previous issue date: 2011-02-10Bitstream added on 2014-06-13T20:10:06Z : No. of bitstreams: 1
silva_da_me_sjrp.pdf: 1617803 bytes, checksum: ac272edc3fa2d00a58fa6e743064acda (MD5)Embolização e quimioembolização são exemplos de procedimentos minimamente invasivos aplicados em medicina com objetivo de evitar e/ou amenizar efeitos colaterais causados por tratamentos e intervenções cirúrgicas convencionais. Partículas de poli(álcool vinílico) (PVA) destacam-se entre os materiais utilizados nesses procedimentos por apresentarem características físico-químicas desejáveis como elevada compressibilidade, biocompatibilidade e biodegradabilidade. A proposta deste trabalho foi sintetizar e caracterizar microesferas de PVA/PVAc com tamanhos de partículas entre 30µm e 1200µm por reação de polimerização em suspensão seguida por uma etapa de saponificação. Além disso, estudar a influência da concentração de solução alcalina no processo de saponificação. A caracterização morfológica e estrutural foi feita com auxílio das técnicas de microscopia eletrônica de varredura (MEV) e difração de raios-X (DRX). Além da caracterização físico-química, foi realizado o estudo histopatológico mediante implante subcutâneo das partículas em ratos, análise de dimensão fractal e entropia de Shannon. Os resultados mostraram que a concentração de solução alcalina exerce forte influência na cristalinidade, coloração e características superficiais do polímero obtido. As partículas com alta cristalinidade (saponificadas com solução 25 mol/L de NaOH) induziram à reação inflamatória similar ao comportamento observado para partículas disponíveis comercialmente, enquanto que as partículas menos cristalinas (saponificadas com solução 4 mol/L de NaOH) resultaram em baixa intensidade de reação inflamatória no tecido celular subcutâneo dos ratos. Dimensão fractal...
Embolization and chemoembolization are examples of minimally invasive procedures applied in medicine in order to avoid and/or reduce side effects caused by conventional treatments and surgeries. Particles of poly(vinyl alcohol) (PVA) stand out among these materials due to desirable physical and chemical characteristics such as high compressibility, biocompatibility and biodegradability. The purpose of this study was to synthesize and characterize PVA/PVAc microspheres with sizes between 30µm and 1200µm by reaction of suspension polymerization step followed by a process of saponification. Moreover, study the influence of the concentration of alkaline solution in the process of saponification. The morphological and structural characterization was made with scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition to the physico-chemical characterization, it was carried the histopathological study by subcutaneous implantation of particles in rats, analysis of fractal dimension and Shannon´s entropy. The results indicated that the concentration of alkaline solution strongly influence the crystallinity, color and surface characteristics of the polymer. Highly crystalline particles (saponified with 25 mol/L NaOH) induced inflammatory reaction similar to the behavior observed for the commercial particles, while particles with lower crystallinity (saponified with 4 mol/L NaOH) presented lower inflammation in the subcutaneous tissue of rats. Fractal dimension and Shannon´s entropy showed satisfactory correlation with the histopathological analysis: the values have changed as the permanence time of particles in rats, behavior was satisfactory from a clinical standpoint because it corroborates the qualitative changes observed in the subcutaneous tissues in response to disturbance of the immune... (Complete abstract click electronic access below)
4
Blažek, Petr. "Entropické modely datového provozu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-220416.
Full textAbstract:
This thesis solves possibility of using entropy for anomaly detection in data communication and especially for security attacks. The main advantage of using entropy is ability to identify unknown attacks because entropy detects changes in network traffic but not the content as existing methods. In this work was tested the suitability of different models entropy (Shannon, Renyi, Tsallis). Also been tested the effect of Renyi and Tsallis parameter on resulting entropy. From the resulting values, I found that all tested entropy achieve good result in the identification of anomalies in network traffic.
5
Livesey, Gillian Elizabeth. "Advancing egress complexity in support of rule-based evacuation modelling." Thesis, University of Ulster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288821.
Full text
6
Macedo, Diego Ximenes. "Fisher information and Shannon entropy of oscillators with position dependent mass." Universidade Federal do CearÃ, 2017. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=18902.
Full textAbstract:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoIn this work we study from both classical and quantum point of view the position dependent mass harmonic oscillator (PDMHO). Classically, we use the Legendre transformation to find the Hamiltonian of the system. Next, we define two functions, and , to simplify the hamiltonian of the PDMHO. By using the Poisson algebra we find the expressions for the position and moment. At last, by using a canonical transformation we relate the equations of the PDMHO to those of the simple harmonic oscillator (SHO). Quantically, we write the Hamiltonian of the PDMHO in terms of the operators and . Next, we consider that these operators satisfy the same algebra that those of the SHO. By assuming that both the classical and quantum PDMHO have the same form, we are able to find a simple form for the PDMHO Hamiltonian. Finally, by transforming the SchrÃdinger equation (SE) of the PDMHO into that of the SHO, we can write the wave function of the PDMHO in terms of that of the SHO. We will study two time-dependent systems, namely and , we observe that as , they tend to a simple harmonic oscillator. For each system we find the position and momentum (classical study), as well as the wave-function (quantum study). For both systems we analyze the the position e momentum uncertainty, the product uncertainty, the fisher information and Shannon entropy, for the ground state, as a function of the parameter .
Neste trabalho estudamos clÃssica e quanticamente o oscilador harmÃnico com massa dependente da posiÃÃo (OHMDP). Na parte clÃssica, utilizamos a transformaÃÃo de Legendre para encontrar a hamiltoniana do sistema. A seguir definimos duas funÃÃes e para escrevermos a hamiltoniana do OHMDP de uma forma mais simples. Utilizando a Ãlgebra de Poisson encontramos as expressÃes para a posiÃÃo e o momento. Por fim, atravÃs de uma transformaÃÃo canÃnica veremos como relacionar as equaÃÃes do OHMDP com aquelas do oscilador harmÃnico simples (OHS). Na parte quÃntica, escrevemos a hamiltoniana do OHMDP em termos de operadores e . Em seguida, vamos supor que estes operadores satisfaÃam a mesma relaÃÃo de comutaÃÃo que os operadores abaixamento e levantamento do OHS. Analisando que condiÃÃo deve ser satisfeita para que os osciladores OHMDP clÃssico e quÃntico tenham o mesmo potencial, encontramos uma forma simplificada da hamiltoniana do OHMDP. Em seguida, transformamos a equaÃÃo de SchrÃdinger (ES) para o OHMDP na ES para o OHS. Assim, obtemos a funÃÃo de onda do OHMDP em termos da funÃÃo de onda do OHS. Estudaremos dois sistemas com massa dependente da posiÃÃo, a saber: e , vemos que quando , recaÃmos no OHS. Para cada sistema encontraremos a posiÃÃo e o momento (estudo clÃssico), bem como a funÃÃo de onda (estudo quÃntico). Para os dois sistemas analisaremos tambÃm o comportamento da incerteza na posiÃÃo, incerteza no momento, produto de incerteza, informaÃÃo de Fisher e entropia de Shannon, para o estado fundamental, em funÃÃo do parÃmetro de deformaÃÃo .
7
Koch, David. "Investigation and improvement of criticality calculations in MCNP5 involving Shannon entropy convergence." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53484.
Full textAbstract:
Criticality calculations are often performed in MCNP5 using the Shannon entropy as an indicator of source convergence for the given neutron transport problem. The Shannon entropy is a concept that comes from information theory. The Shannon entropy is calculated for each batch in MCNP5, and it has been shown that the Shannon entropy tends to converge to a single value as the source distribution converges. MCNP5 has its own criteria for when the Shannon entropy has converged and recommends a number for how many batches should be skipped; however, this value for how many batches should be skipped is often not very accurate and has room for improvement.
This work will investigate an approach for using the Shannon entropy source distribution convergence information obtained in a shorter simulation to predict the required number of generations skipped in the reference case with desired statistical precision. In several test cases, it has been found that running a lesser number of particles per batch produces a similar Shannon entropy graph when compared to running more particles per batch. Then, by appropriate adjustment through a synthetic model, one is able to determine when the Shannon entropy will converge by running fewer particles, finding the point where it converges and then using this value to determine how many batches one should skip for a given problem. This reduces computational time and any "guessing" involved when deciding how many batches to skip. Thus, the purpose of this research is to develop a model showing how one can use this concept and produce a streamlined approach for applying this concept to a criticality problem.
8
Taing, Lieng. "Approches bioinformatiques pour l'exploitation des données génomiques." Phd thesis, Conservatoire national des arts et metiers - CNAM, 2012. http://tel.archives-ouvertes.fr/tel-00814272.
Full textAbstract:
Les technologies actuelles permettent d'explorer le génome entier pour identifier des variants génétiques associés à des phénotypes particuliers, notamment de maladies. C'est le rôle de la bioinformatique de répondre à cette problématique. Dans le cadre de cette thèse, un nouvel outil logiciel a été développé qui permet de mesurer avec une bonne précision le nombre de marqueurs génétiques effectivement indépendants correspondant à un ensemble de marqueurs génotypés dans une population donnée. Cet algorithme repose sur la mesure de l'entropie de Shannon contenue au sein de ces marqueurs, ainsi que des niveaux d'information mutuelle calculés sur les paires de SNPs choisis au sein d'une fenêtre de SNPs consécutifs, dont la taille est un paramètre du programme. Il a été montré que ce nombre de marqueurs indépendants devient constant dès que la population est homogène avec une taille suffisante (N > 60 individus) et que l'on utilise une fenêtre assez grande (taille > 100 SNPs). Ce calcul peut avoir de nombreuses applications pour l'exploitation des données.Une analyse génome-entier a été réalisée sur le photo-vieillissement. Elle a porté sur 502 femmes caucasiennes pour lesquelles un grade de photo-vieillissement a été évalué selon une technologie bien établie. Les femmes ont été génotypées sur des puces Illumina OmniOne (1M SNPs), et deux gènes ont été identifiés (STXBP5L et FBX040) associés à un SNP passant le seuil de Bonferroni, dont l'implication dans le photo-vieillissement était jusqu'alors inconnue. De plus, cette association a aussi été retrouvé dans deux autres phénotypes suggérant un mécanisme moléculaire commun possible entre le relâchement cutané et les rides. On n'observe pas de réplication au niveau du critère lentigines, la troisième composante étudiée du photo-vieillissement.Ces travaux sont en cours de publication dans des revues scientifiques internationales à comité de lecture.
9
Tánchez, Luis Eduardo Ortiz. "Entropies and predictability of variability indices of the tropical Pacific." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2004. http://dx.doi.org/10.18452/15055.
Full textAbstract:
Die folgende Arbeit befasst sich mit der Vorhersagbarkeit und der zeitlichen Struktur von Indizes der klimatischen Variabilität des tropischen Pazifiks, bekannt in der Jahrzentenskala als El-Nino-Southern Oscillation (ENSO). Untersucht wurden die Zeitreihen der Anomalien und Persistenzen der Southern Oscillation Index (SOI), den Multivariate ENSO Index (MEI) und die Meeresoberflächentemperatur (SST). Methoden der dynamischen und bedingten schannonschen Entropien wurden für die Untersuchung der Vorhersagbarkeit von symbolischen Sequenzen der Zeitreihen angewendet. Die Untersuchung der bedingten Entropien für symbolische Sequenzen ergibt, dass die meist vorhersagbare Evente von ENSO nach konstanten Teilsequenzen stattfinden. Für mehrere Evente sind zeitliche Korrelationen nachweisbar, die die Vorhersagbarkeit eines Symbols nach einer Teilsequenz in Funktion derer Länge bestimmen. Die Evolution nach Teilsequenzen, die Übergangszuständen entsprechen, sind mit vergleichsweiseniedrigeren Vorhersagbarkeiten versehen. Dabei ist auf die meist vorhersagbaren Teilsequenzen im Detail eingegangen. Es wurde weiterhin festgestellt, dass sich die SST in den meisten Fällen als die zuverlässigste Informationsquelle erweist. Die Analyse der Waveletspektren der Zeitreihen zeigt starke Periodizitäten der Ordnung zwischen 2 und 4 Jahren, die zwischen 1900 und 1960, und 1970 und 2000 in ENSO auftreten. Es besteht Evidenz dafür, dass diese Frequenzkomponenten nicht von einem gefiteten Markovprozess erster Ordnung zurückzuführen sind. Eine Steigung der Frequenzkomponenten zu niedrigeren Perioden ist weiterhin in den Anomalien der Meerestemperatur vorzuweisen.This doctoral thesis is concerned with the problems of the predictability and the temporal structure of indices of the climatic variability in the tropical Pacific, which is known in the scale of decades as El Nino-Southern Oscillation (ENSO). For this purpose, time series of the anomalies and persistences of the Southern Oscillation Index (SOI), Multivariate ENSO Index (MEI) and of the Sea Surface Temperature (SST) were investigated. Methods of the dynamical and conditional shannon entropies were applied for the investigation of the predictability of symbolic sequences derived from the time series. The investigation of the conditional entropies for symbolic sequences shows that the most probable Events of ENSO occur after constant short sequences. Time correlations are found for several events; these determine the predictability of a sequence as a function of its length. The evolutions of short sequences representing transitions between ENSO states are relatively less predictable. The most predictable short sequences have been studied in detail. It was further found that, in most cases, SST is the most reliable information source. The analysis of the wavelet spectra of the time series shows strong periodicities of 2 to 4 years, which appear between 1900 and 1960, and between 1970 and 2000 in ENSO. There is evidence of a non-markovian process being responsible for these frequency components. Furthermore, the anomalies of the SST series show a gradient of frequency components towards smaller periods.
10
Macdonald, Ruaridh (Ruaridh R. ). "Investigation of improved methods for assessing convergence of models in MCNP using Shannon entropy." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76954.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2012."June 2012." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 42).
Monte Carlo computationals methods are widely used in academia to analyze nuclear systems design and operation because of their high accuracy and the relative ease of use in comparison to deterministic methods. However, current Monte Carlo codes require an extensive knowledge of the physics of a problem as well as the computational methods being used in order to ensure accuracy. This investigation aims to provide better on-the-fly diagnostics for convergence using Shannon entropy and statistical checks for tally undersampling in order to reduce the burden on the code user, hopfully increasing the use and accuracy of Monte Carlo codes. These methods were tested by simulating the OECD/NEA benchmark #1 problem in MCNP. It was found that Shannon entropy does accurately predict the number of batches required for a source distribution to converge, though only when when the Shannon entropy mesh was the size of the tally mesh. The investigation of undersampling showed evidence of methods to predict undersampling on-the-fly using Shannon entropy as well as laying out where future work should lead.
by Ruaridh Macdonald.
S.B.
11
Pineda, José Octávio de Carvalho. "A entropia segundo Claude Shannon: o desenvolvimento do conceito fundamental da teoria da informação." Pontifícia Universidade Católica de São Paulo, 2006. https://tede2.pucsp.br/handle/handle/13330.
Full textAbstract:
Made available in DSpace on 2016-04-28T14:16:25Z (GMT). No. of bitstreams: 1
PINEDA, J O C - A Entropia segundo Claude Shannon.pdf: 616031 bytes, checksum: 1a97063c96e16c98801a4bc8853e1530 (MD5)
Previous issue date: 2006-04-20This dissertation s objective is to investigate the origins of the concept of Entropy as defined by Claude Shannon in the development of the Information Theory, as well as the influences that this concept and other ones from the same theory had over other sciences, especially in Physics. Starting from its origin in Mechanical Statistics, the concept of entropy was transformed into a measure of amount of information by Shannon. Since then the approach proposed by Information Theory has influenced other areas of knowledge and there were many attempts of integrating it with physical theories. The analysis on Information Theory main authors works viewed under a historical outlook, added to the analysis of proposals for its integration with Physics will allow to demonstrate that the integration is currently at the level of approach to physical problems and not at a more fundamental level as it was some scientists expectation
Esta dissertação tem por objetivo investigar as origens do conceito de Entropia formulado por Claude Shannon no desenvolvimento da Teoria da Informação, bem como as influências que este e outros conceitos da mesma teoria tiveram em outras ciências, em especial a Física. Partindo de sua origem na Mecânica Estatística, o conceito de Entropia foi transformado numa medida de quantidade de informação por Shannon. Desde então, a abordagem proposta pela Teoria da Informação influenciou outras áreas do conhecimento, e ocorreram várias tentativas de integrá-la às teorias físicas. A análise das obras dos principais formuladores da Teoria da Informação, colocadas em seu contexto histórico, aliada à análise das propostas de integração desta teoria com a Física permitirá demonstrar que a interação atual entre as áreas ainda se dá ao nível de abordagem dos problemas físicos, e não numa forma mais fundamental como era a expectativa de alguns cientistas
12
Macedo, Diego Ximenes. "Informação de Fisher e entropia de Shannon de osciladores com massa dependente da posição." reponame:Repositório Institucional da UFC, 2017. http://www.repositorio.ufc.br/handle/riufc/22523.
Full textAbstract:
MACEDO, D. X. Informação de Fisher e entropia de Shannon de osciladores com massa dependente da posição. 2017. 65 f. Tese (Doutorado em Física) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017.Submitted by Giordana Silva (giordana.nascimento@gmail.com) on 2017-04-12T20:33:31Z No. of bitstreams: 1 2017_tese_dxmacedo.pdf: 1506351 bytes, checksum: 0451b11cb3bbdfca718fe5d35f2c8a80 (MD5)
Approved for entry into archive by Giordana Silva (giordana.nascimento@gmail.com) on 2017-04-12T20:34:02Z (GMT) No. of bitstreams: 1 2017_tese_dxmacedo.pdf: 1506351 bytes, checksum: 0451b11cb3bbdfca718fe5d35f2c8a80 (MD5)
Made available in DSpace on 2017-04-12T20:34:02Z (GMT). No. of bitstreams: 1 2017_tese_dxmacedo.pdf: 1506351 bytes, checksum: 0451b11cb3bbdfca718fe5d35f2c8a80 (MD5) Previous issue date: 2017
In this work we study from both classical and quantum point of view the position dependent mass harmonic oscillator (PDMHO). Classically, we use the Legendre transformation to find the Hamiltonian of the system. Next, we define two functions, and , to simplify the hamiltonian of the PDMHO. By using the Poisson algebra we find the expressions for the position and moment. At last, by using a canonical transformation we relate the equations of the PDMHO to those of the simple harmonic oscillator (SHO). Quantically, we write the Hamiltonian of the PDMHO in terms of the operators and . Next, we consider that these operators satisfy the same algebra that those of the SHO. By assuming that both the classical and quantum PDMHO have the same form, we are able to find a simple form for the PDMHO Hamiltonian. Finally, by transforming the Schrödinger equation (SE) of the PDMHO into that of the SHO, we can write the wave function of the PDMHO in terms of that of the SHO. We will study two time-dependent systems, namely and , we observe that as , they tend to a simple harmonic oscillator. For each system we find the position and momentum (classical study), as well as the wave-function (quantum study). For both systems we analyze the the position e momentum uncertainty, the product uncertainty, the fisher information and Shannon entropy, for the ground state, as a function of the parameter.
Neste trabalho estudamos clássica e quanticamente o oscilador harmônico com massa dependente da posição (OHMDP). Na parte clássica, utilizamos a transformação de Legendre para encontrar a hamiltoniana do sistema. A seguir definimos duas funções e para escrevermos a hamiltoniana do OHMDP de uma forma mais simples. Utilizando a álgebra de Poisson encontramos as expressões para a posição e o momento. Por fim, através de uma transformação canônica veremos como relacionar as equações do OHMDP com aquelas do oscilador harmônico simples (OHS). Na parte quântica, escrevemos a hamiltoniana do OHMDP em termos de operadores e . Em seguida, vamos supor que estes operadores satisfaçam a mesma relação de comutação que os operadores abaixamento e levantamento do OHS. Analisando que condição deve ser satisfeita para que os osciladores OHMDP clássico e quântico tenham o mesmo potencial, encontramos uma forma simplificada da hamiltoniana do OHMDP. Em seguida, transformamos a equação de Schrödinger (ES) para o OHMDP na ES para o OHS. Assim, obtemos a função de onda do OHMDP em termos da função de onda do OHS. Estudaremos dois sistemas com massa dependente da posição, a saber: e , vemos que quando , recaímos no OHS. Para cada sistema encontraremos a posição e o momento (estudo clássico), bem como a função de onda (estudo quântico). Para os dois sistemas analisaremos também o comportamento da incerteza na posição, incerteza no momento, produto de incerteza, informação de Fisher e entropia de Shannon, para o estado fundamental, em função do parâmetro de deformação.
13
Liu, Wei. "The Effective Spin Concept to Study the Properties of the Shannon Entropy of Arrays of Elastic Scatterers." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1331300313.
Full text
14
Silva, Gilvan Ferreira. "Oscilador harmônico Caldirola-Kanai e aplicação da Teoria da Informação de Fisher e Entropia de Shannon." reponame:Repositório Institucional da UFC, 2017. http://www.repositorio.ufc.br/handle/riufc/23278.
Full textAbstract:
SILVA, G. F. Oscilador harmônico de Caldirola-Kanai e aplicação da Teoria da Informação de Fisher e Entropia de Shannon. 2017. 61 f. Dissertação (Mestrado em Física) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017.Submitted by Pós-Graduação em Física (posgrad@fisica.ufc.br) on 2017-06-13T15:46:22Z No. of bitstreams: 1 2017_ dis_gfsilva.pdf: 1262336 bytes, checksum: 0e6010a0850b0ac2aed199269f2335be (MD5)
Approved for entry into archive by Giordana Silva (giordana.nascimento@gmail.com) on 2017-06-13T21:30:10Z (GMT) No. of bitstreams: 1 2017_ dis_gfsilva.pdf: 1262336 bytes, checksum: 0e6010a0850b0ac2aed199269f2335be (MD5)
Made available in DSpace on 2017-06-13T21:30:10Z (GMT). No. of bitstreams: 1 2017_ dis_gfsilva.pdf: 1262336 bytes, checksum: 0e6010a0850b0ac2aed199269f2335be (MD5) Previous issue date: 2017
CAPES
In this dissertation, we give a brief historical overview of the elements that form it, namely Quantum Harmonic Oscillators with explicit temporal dependence; Lewis & Riesenfelds Method of the Invariants associated with Hartley & Rays technique; Shannon’s entropy and Fisher’s information theory. In this introductory description, we seek to present a procedural view of scientific knowledge. Also, in the introduction, we present the motivations for the execution of the academic work and its organization. In a later chapter, we describe Lewis and Riesenfeld’s formalism applied to oscillators that have an explicit temporal dependency. To better describe it, we divide the chapter into sections in which we define the Invariant, find its self-states, relate the self-states with the Schrödinger’s solution, and apply the formalism to the time-dependent oscillator which, in our work, was the well-known Caldirola-Kanai with M(t) = m eγt. We find the solutions in the coordinate of the position and, after that, we work with the wave function of the ground state. In the following chapter, we determine the uncertainty. To do so, we use the creation and destruction algebra of operators, So known by physicists. We find the Shannon’s entropy and Fisher’s information. We do an analysis of the analytical and graphical results, establishing a comparison between these techniques.
Nesta dissertação, fazemos um breve histórico dos elementos que a compõem, a saber, Osciladores Harmônicos Quânticos com dependência temporal explícita; Método dos Invariantes de Lewis e Riesenfeld associado com a técnica de Hartley e Ray; Entropia de Shannon e Teoria da informação de Fisher. Na descrição introdutória, buscamos apresentar uma visão processual dos conhecimentos científicos. Ainda, na introdução, apresentamos as motivações para a execução do trabalho acadêmico e sua organização. Em capítulo posterior, descrevemos o formalismo de Lewis e Riesenfeld aplicados a osciladores que têm uma dependência temporal explícita. Para melhor descrever, dividimos o capítulo em seções nas quais definimos o Invariante, encontramos seus autoestados, relacionamos os autoestados com a solução de Schrödinger e aplicamos o formalismo ao oscilador com dependência temporal que, para o nosso trabalho, foi o conhecido Oscilador de Caldirola-Kanai com M(t) = m eᵞt. Encontramos as soluções na coordenada da posição e, após, trabalhamos com a função de onda do estado fundamental. No capítulo seguinte, determinamos a incerteza. Para tanto, utilizamos a álgebra de operadores criação e destruição, tão conhecida pelos físicos. Encontramos a entropia de Shannon e a Informação de Fisher. Por fim, uma análise dos resultados analíticos e gráficos, estabelecendo uma comparação entre as técnicas.
15
Zegers, Pablo, B. Frieden, Carlos Alarcón, and Alexis Fuentes. "Information Theoretical Measures for Achieving Robust Learning Machines." MDPI AG, 2016. http://hdl.handle.net/10150/621411.
Full textAbstract:
Information theoretical measures are used to design, from first principles, an objective function that can drive a learning machine process to a solution that is robust to perturbations in parameters. Full analytic derivations are given and tested with computational examples showing that indeed the procedure is successful. The final solution, implemented by a robust learning machine, expresses a balance between Shannon differential entropy and Fisher information. This is also surprising in being an analytical relation, given the purely numerical operations of the learning machine.
16
Kawashita, Silvia Yukie [UNIFESP]. "Homologia, paralogia e função da DGF-1, uma família gênica específica de Trypanosoma cruzi." Universidade Federal de São Paulo (UNIFESP), 2009. http://repositorio.unifesp.br/handle/11600/9695.
Full textAbstract:
Made available in DSpace on 2015-07-22T20:50:18Z (GMT). No. of bitstreams: 0
Previous issue date: 2009-08-26Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Pesquisa e Desenvolvimento (CNPq)
World Health Organization (WHO)
Howard Hughes Medical Institute
Proteinas de adesao celular sao essenciais para a invasao celular do hospedeiro mamifero pelo parasita Trypanosoma cruzi. Neste trabalho, nos mostramos que membros de gDispersed Gene Family-1 h, originalmente descrita como uma familia de sequencias nucleares repetitivas presente em varios cromossomos e compondo a terceira maior familia genica especifica deste parasita, contem caracteristicas de adesinas, incluindo quatro segmentos com similaridade significante a sequencia da subunidade ƒÀ7 de integrina humana. Ensaios de biotinilacao da superficie de parasitas e citometria de fluxo com anticorpos anti-DGF-1 indicaram que os membros dessa familia genica sao expressos na superficie das formas tripomastigotas. A genealogia de DGF-1, inferida por algoritmos de rede a partir de dados do Projeto Genoma da linhagem CL Brener de T. cruzi, sugere que essa familia genica pode ser dividida em pelo menos tres grupos com diferentes padroes de distribuicao de seus dominios funcionais. Analisando o perfil de uso dos codons, observou-se que as copias expressas apresentavam um uso preferencial de codons, favorecendo as bases GC, ao passo que copias nao-expressas, incluindo alguns pseudogenes, apresentavam uma distribuicao homogenea no uso de codons. A entropia informacional de Shannon foi utilizada como uma medida da variabilidade de sequencia e revelou que quatro segmentos de alta entropia coincidem com modulos funcionais putativos das proteinas preditas. Contradizendo a ideia de que alta variabilidade esta associada a selecao positiva, os resultados de dois testes distintos de selecao mostraram que posicoes altamente variaveis nao estao necessariamente sob selecao positiva. Nossa hipotese e de que membros de DGF-1 estao associados com a habilidade do T. cruzi se ligar a proteinas da matriz extracelular, como fibronectina e laminina, e especulamos sobre os mecanismos que gerariam diversidade nessas moleculas na ausencia de selecao.
Surface adhesion proteins are essential for Trypanosoma cruzi invasion of mammalian cells. Here we show that Dispersed Gene Family-1 (DGF-1) members, previously identified as nuclear repeated sequences present in several chromosomes and comprising the third largest T. cruzi-specific gene family, have conserved adhesin motifs including four segments with significant similarity to human beta 7 integrin. Flow cytometry and biotinylation assays with anti-DGF-1 antibodies indicated that, as expected, DGF-1 members are expressed on the trypomastigote surface. The DGF-1 genealogy, inferred using T. cruzi Genome Project data and network phylogeny algorithms, suggests that this gene family is separated in at least three groups with differential distribution of functional domains. To identify which members of this gene family are expressed we used a combined approach of RT-PCR and codon usage profiles, showing that expressed members have a very biased codon usage favoring GC whereas non-expressed members have a homogeneous distribution. Shannon information entropy was used to measure sequence variability and revealed four major high entropy segments in the extracellular domain of DGF-1 overlapping with important putative functional modules of the predicted proteins. Testing for natural selection, however, indicated that these high entropy segments were not under positive selection, which contradicts the notion that positive selection is the cause of high variability in specific domains of a protein relative to other less variable regions in the same molecule. We hypothesize that members of the DGF-1 family are associated with the ability of T. cruzi to bind extracellular matrix proteins, such as fibronectin and laminin, and speculate on mechanisms that would be generating the localized diversity in these molecules in the absence of selection.
FAPESP: 03/05317-0
TEDE
BV UNIFESP: Teses e dissertações
17
Barbosa, Aline Amabile Viol. "Entropia de Shannon e propriedades topol?gicas de redes funcionais do c?rebro humano sob efeito de Ayahuasca." PROGRAMA DE P?S-GRADUA??O EM F?SICA, 2015. https://repositorio.ufrn.br/jspui/handle/123456789/21549.
Full textAbstract:
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-12-29T17:50:30Z
No. of bitstreams: 1
AlineAmabileViolBarbosa_TESE.pdf: 6434010 bytes, checksum: e3a07408423ecca8798dc99b1a3c1f71 (MD5)Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-02T20:15:57Z (GMT) No. of bitstreams: 1 AlineAmabileViolBarbosa_TESE.pdf: 6434010 bytes, checksum: e3a07408423ecca8798dc99b1a3c1f71 (MD5)
Made available in DSpace on 2017-01-02T20:15:57Z (GMT). No. of bitstreams: 1 AlineAmabileViolBarbosa_TESE.pdf: 6434010 bytes, checksum: e3a07408423ecca8798dc99b1a3c1f71 (MD5) Previous issue date: 2015-09-18
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
O recente desenvolvimento do poder de processamento computacional vem trazendo para dentro do escopo da f?sica e outras ci?ncia exatas desafios at? ent?o considerados exclusivos de ci?ncias qualitativas. M?todos e conceitos da F?sica t?m contribu?do para avan?os em diversas ?reas, dentre elas neuroci?ncia. Vimos na presente tese de doutorado estudar o comportamento do c?rebro humano em estado alterado de consci?ncia, a partir de mapas funcionais gerados por resson?ncia magn?tica funcional (fMRI, {\it functional Magnetic Ressonance}) usando ferramentas da f?sica estat?stica e da teoria de redes complexas. Analisamos dados de fMRI do c?rebro de sujeitos em estado de repouso em duas condi??es distintas: em estado natural e em estado alterado de consci?ncia pela ingest?o de uma infus?o psicoativa, proveniente da cultura ind?gena amaz?nica, chamada Ayahuasca. Em linhas gerais fomos guiados por duas perguntas. O Ayahuasca causa diferen?as nas redes funcionais do c?rebro? Como quantificar essas diferen?as? Inicialmente constru?mos redes complexas usando os dados de fMRI para mapear informa??es das redes funcionais do c?rebro de cada sujeito em ambas condi??es. A seguir analisamos as propriedades estat?sticas e topol?gicas dessas redes. Comparando as redes geradas a partir dos dados adquiridos antes e depois da ingest?o do Ayahuasca, detectamos duas mudan?as importantes nas propriedades estat?sticas e topol?gicas. Encontramos primeiramente um aumento na entropia de Shannon da distribui??o de grau. Encontramos tamb?m uma segunda mudan?a importante: Uma varia??o na topologia que interfere nas efici?ncias das redes referentes ao estado alterado. Parte das mudan?as nas efici?ncias de rede v?o al?m do que pode ser explicado exclusivamente pelo aumento de entropia. Interpretamos e discutimos esses dois resultados no contexto de neuroci?ncia. Comentamos tamb?m sobre a como a quantifica??o de informa??es das redes funcionais pode ser melhorar nossa compreens?o do funcionamento do c?rebro humano e, consequentemente, contribuir para o desenvolvimento de novas metodologias em diagn?stico e tratamento de dist?rbios psiqui?tricos ainda pouco compreendidos.
An important problem in nonlinear dynamics and statistical physics relates to the quantitative description of the behavior of complex systems. The human brain is one such system. Methods and concepts used in physics have contributed to the development of diverse fields, including neuroscience. In this thesis, we investigate the behavior of the human brain in altered states of consciousness. We study the functional maps of the brain generated by functional magnetic resonance imaging (fMRI), using the tools of statistical physics and the theory of complex networks. We analyze resting state fMRI data of the brains of 9 human subjects under two distinct conditions: under normal waking state and in an altered state of consciousness, induced by ingestion of the psychoactive infusion known as Ayahuasca, of Amazonian indigenous origin. Our study was broadly motivated by two questions: Does Ayahuasca affect the functional brain networks? How can we quantify these effects? We initially constructed complex network models of the brain using the fMRI data, before and after ingestion of Ayahuasca. We next analyzed the statistical and topological properties of these networks. Comparing the networks generated from the data before and after Ayahuasca ingestion, we find some significant changes which we highlight: an increase in the Shannon entropy, a increase in the mean geodesic distance and changes in network efficiencies. The increase in mean distance indicates a global expansion of the brain networks. This suggests a decrease in global integration of brain regions. Moreover, the increase in the entropy of the degree distribution suggests an increase in the range of possibilities of functional patterns. The change in the network efficiencies goes beyond what can be accounted for by the changes in degree distribution. We discuss and present potential interpretations of our results in the context of neuroscience.
18
Sheikhi, Farid. "Entropy Filter for Anomaly Detection with Eddy Current Remote Field Sensors." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31100.
Full textAbstract:
We consider the problem of extracting a specific feature from a noisy signal generated
by a multi-channels Remote Field Eddy Current Sensor. The sensor is installed on a
mobile robot whose mission is the detection of anomalous regions in metal pipelines.
Given the presence of noise that characterizes the data series, anomaly signals could
be masked by noise and therefore difficult to identify in some instances. In order
to enhance signal peaks that potentially identify anomalies we consider an entropy
filter built on a-posteriori probability density functions associated with data series.
Thresholds based on the Neyman-Pearson criterion for hypothesis testing are derived.
The algorithmic tool is applied to the analysis of data from a portion of pipeline with
a set of anomalies introduced at predetermined locations. Critical areas identifying
anomalies capture the set of damaged locations, demonstrating the effectiveness of
the filter in detection with Remote Field Eddy Current Sensor.
19
Regnault, Philippe. "Différents problèmes liés à l'estimation de l'entropie de Shannon d'une loi, d'un processus de Markov." Phd thesis, Université de Caen, 2011. http://tel.archives-ouvertes.fr/tel-00673694.
Full textAbstract:
On étudie à la fois l'estimation de l'entropie de Shannon d'une probabilité à partir d'observations indépendantes ou markoviennes, et l'estimation du taux d'entropie d'un processus markovien de sauts d'espace d'état fini, à partir d'observations continues ou discrètes. Plusieurs problèmes connexes sont traités. Certains apparaissent en amont de l'estimation, comme l'étude de la géométrie de la divergence de Kullback-Leibler en lien avec la transformation escorte. D'autres apparaissent comme des applications des résultats d'estimation obtenus. On construit ainsi des tests sur le niveau d'entropie d'une probabilité, à partir d'un principe de grandes déviations pour la suite des estimateurs empiriques de l'entropie d'une suite de variables indépendantes. On étudie également diverses propriétés en lien avec l'estimation de l'entropie et du taux d'entropie de files d'attente modélisées par des processus markoviens de naissance et de mort.
20
Silva, Danilo Antonio da. "Síntese e caracterização de partículas de poli(álcool vinílico) utilizadas em aplicações biomédicas : contribuição da análise fractal e entropia de Shannon /." São José do Rio Preto : [s.n.], 2011. http://hdl.handle.net/11449/87540.
Full textAbstract:
Resumo: Embolização e quimioembolização são exemplos de procedimentos minimamente invasivos aplicados em medicina com objetivo de evitar e/ou amenizar efeitos colaterais causados por tratamentos e intervenções cirúrgicas convencionais. Partículas de poli(álcool vinílico) (PVA) destacam-se entre os materiais utilizados nesses procedimentos por apresentarem características físico-químicas desejáveis como elevada compressibilidade, biocompatibilidade e biodegradabilidade. A proposta deste trabalho foi sintetizar e caracterizar microesferas de PVA/PVAc com tamanhos de partículas entre 30µm e 1200µm por reação de polimerização em suspensão seguida por uma etapa de saponificação. Além disso, estudar a influência da concentração de solução alcalina no processo de saponificação. A caracterização morfológica e estrutural foi feita com auxílio das técnicas de microscopia eletrônica de varredura (MEV) e difração de raios-X (DRX). Além da caracterização físico-química, foi realizado o estudo histopatológico mediante implante subcutâneo das partículas em ratos, análise de dimensão fractal e entropia de Shannon. Os resultados mostraram que a concentração de solução alcalina exerce forte influência na cristalinidade, coloração e características superficiais do polímero obtido. As partículas com alta cristalinidade (saponificadas com solução 25 mol/L de NaOH) induziram à reação inflamatória similar ao comportamento observado para partículas disponíveis comercialmente, enquanto que as partículas menos cristalinas (saponificadas com solução 4 mol/L de NaOH) resultaram em baixa intensidade de reação inflamatória no tecido celular subcutâneo dos ratos. Dimensão fractal... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: Embolization and chemoembolization are examples of minimally invasive procedures applied in medicine in order to avoid and/or reduce side effects caused by conventional treatments and surgeries. Particles of poly(vinyl alcohol) (PVA) stand out among these materials due to desirable physical and chemical characteristics such as high compressibility, biocompatibility and biodegradability. The purpose of this study was to synthesize and characterize PVA/PVAc microspheres with sizes between 30µm and 1200µm by reaction of suspension polymerization step followed by a process of saponification. Moreover, study the influence of the concentration of alkaline solution in the process of saponification. The morphological and structural characterization was made with scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition to the physico-chemical characterization, it was carried the histopathological study by subcutaneous implantation of particles in rats, analysis of fractal dimension and Shannon's entropy. The results indicated that the concentration of alkaline solution strongly influence the crystallinity, color and surface characteristics of the polymer. Highly crystalline particles (saponified with 25 mol/L NaOH) induced inflammatory reaction similar to the behavior observed for the commercial particles, while particles with lower crystallinity (saponified with 4 mol/L NaOH) presented lower inflammation in the subcutaneous tissue of rats. Fractal dimension and Shannon's entropy showed satisfactory correlation with the histopathological analysis: the values have changed as the permanence time of particles in rats, behavior was satisfactory from a clinical standpoint because it corroborates the qualitative changes observed in the subcutaneous tissues in response to disturbance of the immune... (Complete abstract click electronic access below)
Orientador: Prof. Dr. José Geraldo Nery
Coorientador: Dra. Rosa Sayoko Kawasaki-Oyama
Banca: José Geraldo Nery
Banca: Moacir Fernandes de Godoy
Banca: Sebastião Roberto Taboga
Mestre
21
Grigoli, Francesco. "Studio dei codici, trasmissione e correzione efficiente di un messaggio." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20965/.
Full textAbstract:
L'elaborato si prefigge di descrivere come avviene la codifica, la decodifica e la correzione di errori in una trasmissione dati, sfruttando l'entropia di Shannon, la codifica di Huffmann e i codici di Hamming.
22
Vennos, Amy Demetra Geae. "Security of Lightweight Cryptographic Primitives." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103781.
Full textAbstract:
Internet-of-Things (IoT) devices are increasing in popularity due to their ability to help automate many aspects of daily life while performing these necessary duties on billions of low-power appliances. However, the perks of these small devices also come with additional constraints to security. Security always has been an issue with the rise of cryptographic backdoors and hackers reverse engineering the security protocols within devices to reveal the original state that was encrypted. Security researchers have done much work to prevent attacks with high power algorithms, such as the international effort to develop the current Advanced Encryption Standard (AES). Unfortunately, IoT devices do not typically have the computational resources to implement high-power algorithms such as AES, and must rely on lightweight primitives such as pseudorandom number generators, or PRNGs.This thesis explores the effectiveness, functionality, and use of PRNGs in different applications. First, this thesis investigates the confidentiality of a single-stage residue number system PRNG, which has previously been shown to provide extremely high quality outputs for simulation and digital communication applications when evaluated through traditional techniques like the battery of statistical tests used in the NIST Random Number Generation and DIEHARD test suites or in using Shannon entropy metrics. In contrast, rather than blindly performing statistical analyses on the outputs of the single-stage RNS PRNG, this thesis provides both white box and black box analyses that facilitate reverse engineering of the underlying RNS number generation algorithm to obtain the residues, or equivalently the key, of the RNS algorithm. This thesis develops and demonstrate a conditional entropy analysis that permits extraction of the key given a priori knowledge of state transitions as well as reverse engineering of the RNS PRNG algorithm and parameters (but not the key) in problems where the multiplicative RNS characteristic is too large to obtain a priori state transitions. This thesis then discusses multiple defenses and perturbations for the RNS system that defeat the original attack algorithm, including deliberate noise injection and code hopping. We present a modification to the algorithm that accounts for deliberate noise, but rapidly increases the search space and complexity. Lastly, a comparison of memory requirements and time required for the attacker and defender to maintain these defenses is presented.
The next application of PRNGs is in building a translation for binary PRNGs to non-binary uses like card shuffling in a casino. This thesis explores a shuffler algorithm that utilizes RNS in Fisher-Yates shuffles, and that calls for inputs from any PRNG. Entropy is lost through this algorithm by the use of PRNG in lieu of TRNG and by its RNS component: a surjective mapping from a large domain of size $2^J$ to a substantially smaller set of arbitrary size $n$. Previous research on the specific RNS mapping process had developed a lower bound on the Shannon entropy loss from such a mapping, but this bound eliminates the mixed-radix component of the original formulation. This thesis calculates a more precise formula which takes into account the radix, $n$. This formulation is later used to specify the optimal parameters to simulate the shuffler with different test PRNGs. After implementing the shuffler with PRNGs with varying output entropies, the thesis examines the output value frequencies to discuss if utilizing PRNG is a feasible alternative for casinos to the higher-cost TRNG.Master of Science
Cryptography, or the encrypting of data, has drawn widespread interest for years, initially sparking public concern through headlines and dramatized reenactments of hackers targeting security protocols. Previous cryptographic research commonly focused on developing the quickest, most secure ways to encrypt information on high-power computers. However, as wireless low-power devices such as smart home, security sensors, and learning thermostats gain popularity in ordinary life, interest is rising in protecting information being sent between devices that don't necessarily have the power and capabilities as those in a government facility. Lightweight primitives, the algorithms used to encrypt information between low-power devices, are one solution to this concern, though they are more susceptible to attackers who wish to reverse engineer the encrypting process. The pesudorandom number generator (PRNG) is a type of lightweight primitive that generates numbers that are essentially random even though it is possible to determine the input value, or seed, from the resulting output values. This thesis explores the effectiveness and functionality of PRNGs in different applications. First, this thesis explores a PRNG that has passed many statistical tests to prove its output values are random enough for certain applications. This project analyzes the quality of this PRNG through a new lens: its resistance to reverse engineering attacks. The thesis describes and implements an attack on the PRNG that allows an individual to reverse engineer the initial seed. The thesis then changes perspective from attacker to designer and develop defenses to this attack: by slightly modifying the algorithm, the designer can ensure that the reverse engineering process is so complex, time-consuming, and memory-requiring that implementing such an attack would be impractical for an attacker. The next application of PRNGs is in the casino industry, in which low-power and cost-effective automatic card shufflers for games like poker are becoming popular. This thesis explores a solution for optimal shuffling of a deck of cards.
23
Murolo, Giuseppe. "Metodi matematici per l'analisi dell'andatura." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18224/.
Full textAbstract:
Il riconoscimento di una persona è una componente essenziale nella sicurezza o, più nello specifico, nella videosorveglianza. In particolare sono pochissime le tecniche biometriche utilizzabili in una situazione in cui c'è bisogno di un riconoscimento a distanza, o in cui serva poter non interferire con l'attività del soggetto da identificare. L'analisi dell'andatura, della deambulazione, del cammino, è tra queste ed ha un importante potenziale: le informazioni utili possono essere estratte da molti punti di vista diversi e, soprattutto, a distanze maggiori rispetto ad altri approcci biometrici, come l'analisi dell'iride o il riconoscimento facciale. In più, a differenza del riconoscimento tramite impronta digitale, non c'è bisogno di un interazione dell'individuo con l'ambiente.
In quest'elaborato vengono presentati, dopo una breve analisi dello stato dell'arte e dopo un'introduzione dei prerequisiti matematici necessari, due metodi per il riconoscimento dell'andatura, il primo basato sulla Teoria dell'Informazione, l'altro sulla Topologia Persistente.
Entrambi gli approcci vengono testati su due esperimenti diversi, e il secondo metodo si mostra più performante del primo soprattutto nel secondo esperimento, dove nelle andature gli individui della gallery sono sotto particolari condizioni non note a priori che influenzano l'andatura o la silhouette del soggetto (trasportare oggetti, indossare un particolare abbigliamento...).
24
Popovic, Marko. "Application of the Entropy Concept to Thermodynamics and Life Sciences: Evolution Parallels Thermodynamics, Cellulose Hydrolysis Thermodynamics, and Ordered and Disordered Vacancies Thermodynamics." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6996.
Full textAbstract:
Entropy, first introduced in thermodynamics, is used in a wide range of fields. Chapter 1 discusses some important theoretical and practical aspects of entropy: what is entropy, is it subjective or objective, and how to properly apply it to living organisms. Chapter 2 presents applications of entropy to evolution. Chapter 3 shows how cellulosic biofuel production can be improved. Chapter 4 shows how lattice vacancies influence the thermodynamic properties of materials. To determine the nature of thermodynamic entropy, Chapters 1 and 2 describe the roots, the conceptual history of entropy, as well as its path of development and application. From the viewpoint of physics, thermal entropy is a measure of useless energy stored in a system resulting from thermal motion of particles. Thermal entropy is a non-negative objective property. The negentropy concept, while mathematically correct, is physically misleading. This dissertation hypothesizes that concepts from thermodynamics and statistical mechanics can be used to define statistical measurements, similar to thermodynamic entropy, to summarize the convergence of processes driven by random inputs subject to deterministic constraints. A primary example discussed here is evolution in biological systems. As discussed in this dissertation, the first and second laws of thermodynamics do not translate directly into parallel laws for the biome. But, the fundamental principles on which thermodynamic entropy is based are also true for information. Based on these principles, it is shown that adaptation and evolution are stochastically deterministic. Chapter 3 discusses the hydrolysis of cellulose to glucose, which is a key reaction in renewable energy from biomass and in mineralization of soil organic matter to CO2. Conditional thermodynamic parameters, ΔhydG', ΔhydH', and ΔhydS', and equilibrium glucose concentrations are reported for the reaction C6H10O5(cellulose) + H2O(l) ⇄ C6H12O6(aq) as functions of temperature from 0 to 100°C. Activity coefficients of aqueous glucose solution were determined as a function of temperature. The results suggest that producing cellulosic biofuels at higher temperatures will result in higher conversion. Chapter 4 presents the data and a theory relating the linear term in the low temperature heat capacity to lattice vacancy concentration. The theory gives a quantitative result for disordered vacancies, but overestimates the contribution from ordered vacancies because ordering leads to a decreased influence of vacancies on heat capacity.
25
Chima, C. I. "Monitoring and modelling of urban land use in Abuja Nigeria, using geospatial information technologies." Thesis, Coventry University, 2012. http://curve.coventry.ac.uk/open/items/286e264c-3d26-4448-8049-6f2ef3fda727/1.
Full textAbstract:
This thesis addresses three research gaps in published literature. These are, the absence of Object Based Image Analysis (OBIA) methods for urban Land Use and Land Cover (LULC) analysis in Nigeria; the inability to use Nigeriasat-1 satellite data for urban LULC analysis and monitoring urban growth in Nigeria with Shannon’s Entropy Index. Using Abuja as a case study, this research investigated the nature of land use/land cover change (LULCC). Specific objectives were: design of an object based classification method to extract urban LULC; validate a method to extract LULC in developing countries from multiple sources of remotely sensed data; apply the method to extract LULC data; use the outputs to validate an Urban Growth Model (UGM); optimise an UGM to represent patterns and trends and through this iterative process identify and prioritise the driving forces of urban change; and finally use the outputs of the land use maps to determine if planning has controlled land use development. Landsat 7 ETM (2001), Nigeriasat-1 SLIM (2003) and SPOT 5 HRG (2006) sensor data were merged with land use cadastre in OBIA, to produce land use maps. Overall classification accuracies were 92%, 89% and 96% respectively. Post classification analysis of LULCC indicated 4.43% annual urban spread. Shannon’s Entropy index for the study period were 0.804 (2001), 0.898 (2003) and 0.930 (2006). Cellular Automata/Markov analysis was also used to predict urban growth trend of 0.89% per annum. For the first time OBIA has been used for LULC analysis in Nigeria. This research has established that Nigeriasat-1 data can contribute to urban studies using innovative OBIA methods. In addition, that Shannon’s Entropy Index can be used to understand the nature of urban growth in Nigeria. Finally, the drivers of LULCC in Abuja are similar to those of planned capital cities in other developing economies. Land use developments in Abuja can provide an insight into urban dynamics in a developing country’s capital region. OBIA, Shannon’s Entropy Index and UGM can aid urban administrators and provide information for sustainable urban planning and development.
26
Robles, Bernard. "Etude de la pertinence des paramètres stochastiques sur des modèles de Markov cachés." Phd thesis, Université d'Orléans, 2013. http://tel.archives-ouvertes.fr/tel-01058784.
Full textAbstract:
Le point de départ de ce travail est la thèse réalisée par Pascal Vrignat sur la modélisation de niveaux de dégradation d'un système dynamique à l'aide de Modèles de Markov Cachés (MMC), pour une application en maintenance industrielle. Quatre niveaux ont été définis : S1 pour un arrêt de production et S2 à S4 pour des dégradations graduelles. Recueillant un certain nombre d'observations sur le terrain dans divers entreprises de la région, nous avons réalisé un modèle de synthèse à base de MMC afin de simuler les différents niveaux de dégradation d'un système réel. Dans un premier temps, nous identifions la pertinence des différentes observations ou symboles utilisés dans la modélisation d'un processus industriel. Nous introduisons ainsi le filtre entropique. Ensuite, dans un but d'amélioration du modèle, nous essayons de répondre aux questions : Quel est l'échantillonnage le plus pertinent et combien de symboles sont ils nécessaires pour évaluer au mieux le modèle ? Nous étudions ensuite les caractéristiques de plusieurs modélisations possibles d'un processus industriel afin d'en déduire la meilleure architecture. Nous utilisons des critères de test comme les critères de l'entropie de Shannon, d'Akaike ainsi que des tests statistiques. Enfin, nous confrontons les résultats issus du modèle de synthèse avec ceux issus d'applications industrielles. Nous proposons un réajustement du modèle pour être plus proche de la réalité de terrain.
27
Elyoubi, Abderrahim. "Statistiques exhaustives en reconnaissance de formes." Rouen, 1995. http://www.theses.fr/1995ROUES058.
Full textAbstract:
Dans ce travail, nous avons développé une nouvelle approche des modèles de Markov. Le but visé à terme est son application en reconnaissance optique de l'écriture manuscrite. L'analyse faite est fondée sur le constat que les règles de grammaire définies sur un langage naturel agissent sur des séquences longues nécessitant l'emploi de chaines de Markov d'ordre k, élevé. L'augmentation en puissance de k du nombre des états rend un tel modèle pratiquement inapplicable. La méthode développée cherche à définir à partir d'une suite de variables aléatoires représentant les états d'un modèle de Markov d'ordre k, une chaîne de Markov à nombre d'états réduit, exhaustive et calculable de façon récursive. Cette chaîne, appelée chaîne induite de Markov, introduit les propriétés principales du système aléatoire. Elle envisage de regrouper les séquences des états à transitions égales. Une évolution compatible avec le regroupement est indispensable. Ainsi, les lois statistiques du phénomène étudié se déduisent de celles de la chaîne induite et de la suite des observations. En comparaison avec un modèle de Markov classique, un nouveau terme contenant les informations sur la structure des séquences des états apparaît dans la formule d'identification par modèle induit de Markov. Ce terme permet de mieux préciser l'estimation des états du modèle. La lecture automatique des nombres manuscrits en provenance de chèques est un cas qui se prête bien à l'application d'un modèle induit de Markov.
28
Camesasca, Marco. "MULTISCALING ANALYSIS OF FLUIDIC SYSTEMS: MIXING AND MICROSTRUCTURE CHARACTERIZATION." online version, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1144350255.
Full text
29
Ríos, Angulo Solange Guiuliana. "Evaluación del impacto social (SIA) y análisis de posibles conflictos socioambientales (ECA) en un proyecto minero en el sur del Perú usando los modelos matemáticos de Grey Clustering y entropía de Shannon." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2021. http://hdl.handle.net/20.500.12404/19399.
Full textAbstract:
El aspecto social se ha convertido en un factor clave para la viabilidad de los proyectos mineros en América Latina, y Perú no es una excepción. Por esta razón, la presente investigación busca prevenir posibles conflictos socioambientales y pérdidas económicas, que podrían ocurrir durante la ejecución de un proyecto, utilizando modelos cuantitativos. Por consiguiente, esta tesis presenta una justificación económica, social y metodológica. El objetivo es determinar el impacto social y analizar posibles conflictos socioambientales relacionados a un proyecto minero utilizando la metodología “Integration of the grey clustering and entropy-weight methods”, la cual es un modelo integrado del método grey clustering basado en funciones triangulares de Whitenización de punto central y del método de la entropía de Shannon. El caso de estudio es un proyecto minero situado en el sur de Perú, en el que se identificaron cuatro grupos de interés (stakeholders) y siete criterios relacionados a variables sociales propias del lugar. Los resultados obtenidos revelaron que, para las autoridades comunales y los ganaderos de alpacas, el impacto social del proyecto es negativo; mientras que, para el gobierno local y los comerciantes, el impacto es normal, siendo el gobierno local el que presenta un mayor grado de aceptabilidad con respecto a este proyecto. Por otro lado, también se concluye que los criterios con mayor probabilidad de generar conflictos socioambientales son la tasa de empleo y el Producto Bruto Interno (PBI) per cápita relacionados a las variables sociales de empleo y economía, respectivamente. Estos resultados podrían ayudar a los gobiernos central y regional de Perú a buscar las medidas adecuadas para prevenir oposiciones durante la ejecución del proyecto. Finalmente, la presente tesis puede contribuir a abordar cualquier conflicto de ámbito social y ambiental de manera mucho más efectiva, buscando el desarrollo sostenible y equilibrando los aspectos económico, social y ambiental.
30
Cherni, Afef. "Méthodes modernes d'analyse de données en biophysique analytique : résolution des problèmes inverses en RMN DOSY et SM." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ055/document.
Full textAbstract:
Cette thèse s’intéresse à la création de nouvelles approches algorithmiques pour la résolution du problème inverse en biophysiques. Dans un premier temps, on vise l’application RMN de type DOSY: une nouvelle approche de régularisation hybride a été proposée avec un nouvel algorithme PALMA (http://palma.labo.igbmc.fr/). Cet algorithme permet d’analyser des données réelles DOSY avec une précision importante quelque soit leur type. Dans un deuxième temps, notre intérêt s’est tourné vers l’application de spectrométrie de masse. Nous avons proposé une nouvelle approche par dictionnaire dédiée à l’analyse protéomique en utilisant le modèle averagine et une stratégie de minimisation sous contraintes d'une pénalité de parcimonie. Afin d’améliorer la précision de l’information obtenue, nous avons proposé une nouvelle méthode SPOQ, basée sur une nouvelle fonction de pénalisation, résolue par un nouvel algorithme Forward-Backward à métrique variable localement ajustée. Tous nos algorithmes bénéficient de garanties théoriques de convergence, et ont été validés expérimentalement sur des spectres synthétisés et des données réellesThis thesis aims at proposing new approaches to solve the inverse problem in biophysics. Firstly, we study the DOSY NMR experiment: a new hybrid regularization approach has been proposed with a novel PALMA algorithm (http://palma.labo.igbmc.fr/). This algorithm ensures the efficient analysis of real DOSY data with a high precision for all different type. In a second time, we study the mass spectrometry application. We have proposed a new dictionary based approach dedicated to proteomic analysis using the averagine model and the constrained minimization approach associated with a sparsity inducing penalty. In order to improve the accuracy of the information, we proposed a new SPOQ method based on a new penalization, solved with a new Forward-Backward algorithm with a variable metric locally adjusted. All our algorithms benefit from sounded convergence guarantees, and have been validated experimentally on synthetics and real data
31
Moura, Sílvia Cristina Garcia de. "Influência da manobra postural ativa e do diabetes mellitus tipo 2 na variabilidade da frequência cardíaca de homens de meia idade." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/5285.
Full textAbstract:
Made available in DSpace on 2016-06-02T20:19:17Z (GMT). No. of bitstreams: 1
4130.pdf: 7746703 bytes, checksum: 425a15aa93496be6f1802d7a31fd28d2 (MD5)
Previous issue date: 2012-02-29Financiadora de Estudos e Projetos
OBJECTIVE Evaluate the heart rate variability (HRV) of individuals with Type 2 diabetes, in the supine and in response to active postural maneuver from the supine to orthostatic position, by means of linear and non linear analysis and correlate these data. RESEARCH DESIGN AND METHODS Sixteen men with type 2 diabetes (DM) and sixteen control subjects (CG), age-range from 40 to 65 year were studied. The R-R intervals were recorded with a Polar RS800CX for 10 minutes in supine and 10 minutes in the orthostatic position. We assessed HRV using spectral (LFnu, HFnu and LF/HF), symbolic (0V%, 1V%, 2LV% and 2ULV%) analysis, Shannon (SE) and conditional entropy (complexity Index - CI and Normalized Complexity Index- NCI). RESULTS The DM presented higher sympathetic modulation (LFnu) in the supine position than the CG. In active postural maneuver for the variables LFnu and HFnu, DM showed no significant responses. Irrespective of position DM presented lower complexity than CG for SE. The same did not occur with conditional entropy, however, in both groups a reduction in values of entropies was observed with postural change. The reduction in complexity observed by SE was related to an increase in sympathetic modulation (0V%). CONCLUSION Our study showed that DM had higher sympathetic modulation in the supine position, which may be related to less complexity of HRV in this population. In addition, DM did not present the expected response of the autonomic nervous system to active postural maneuver for the variables LFnu and HFnu.
OBJETIVO Avaliar a variabilidade da frequência cardíaca (VFC) de indivíduos com diabetes mellitus tipo 2, na posição supina e em resposta a manobra postural ativa de supino para ortostático, por meio de análise linear e não linear e correlacioná-las. MÉTODOS Foram avaliados dezesseis homens com diabetes mellitus tipo 2 (DM) e dezesseis sujeitos controle (GC), na faixa etária de 40 a 65 anos. Os intervalos R-R (iRR) foram captados por um Polar RS800CX durante 10 minutos na posição supina e 10 minutos na posição ortostática. Avaliou-se a VFC utilizando análises espectral (BFun, AFun e BF/AF), simbólica (0V%, 1V%, 2LV% e 2ULV%), entropia de Shannon (ES) e condicional (índice de complexidade - IC e índice de complexidade normalizado - ICN). RESULTADOS O DM apresentou maior modulação simpática (BFun) na posição supina do que o GC. Na manobra postural ativa para as variáveis BFun e AFun o DM não mostrou resposta significativa. Independentemente da posição DM apresentou menor complexidade (menor ES) do que o GC. O mesmo não ocorreu com a entropia condicional, entretanto em ambos os grupos foi observada redução nos valores das entropias com a mudança postural. A redução da complexidade observada pela ES foi relacionada ao aumento da modulação simpática (0V%). CONCLUSÃO Nosso estudo mostrou que DM apresentou maior modulação simpática na posição supina, a qual pode estar relacionada com a menor complexidade da VFC nessa população. Além disso, DM não apresentou resposta esperada do sistema nervoso autonômico à manobra postural ativa para as variáveis BFun e AFun.
32
Mohammed, Abdulwasey. "Scaling up of peatland methane emission hotspots from small to large scales." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15772.
Full textAbstract:
Methane is an important greenhouse gas that is relatively long-lived in the atmosphere, and wetlands are a major natural source of atmospheric methane. Methane emissions from wetlands are variable across both space and time at scales ranging from meters to continents and a comprehensive accounting of wetland methane efflux is critical for quantifying the atmospheric methane balance. Major uncertainties in quantifying methane efflux arise when measuring and modelling its physical and biological determinants, including water table depth, microtopography, soil temperature, the distribution of aerenchymous vegetation, and the distribution of mosses. Further complications arise with the nonlinear interaction between flux and derivers in highly-heterogeneous wetland landscape. A possible solution for quantifying wetland methane efflux at multiple scales in space (‘upscaling’) is repeated observations using remote sensing technology to acquire information about the land surface across time, space, and spectra. These scaling issues must be resolved to progress in our understanding of the role of wetlands in the global atmospheric methane budget from peatlands. In this thesis, data collected from multiple aircraft and satellite-based remote sensing platforms were investigated to characterize the fine scale spatial heterogeneity of a peatland in southwestern Scotland for the purpose of developing techniques for quantifying (‘upscaling’) methane efflux at multiple scales and space. Seasonal variation in pools such as expansion and contraction was simulated with the LiDAR data to investigate the expansion and contraction of the lakes and pools that could give an idea of increase or decrease in methane emissions. Concepts from information theory applied on the different data sets also revealed the relative loss in some features on peatland surface and relative gain on others and find a natural application for reducing bias in multi-scale spatial classification as well as quantifying the length scales (or scales) at which important surface features for methane fluxes are lost. Results from the wavelet analysis demonstrated the preservation of fine scale heterogeneity up to certain length scale and the pattern on peatland surface was preserved. Variogram techniques were also tested to determine sample size, range and orientation in the data set. All the above has implications on estimating methane budget from the peatland landscape and could reduce the bias in the overall flux estimates. All the methods used can also be applied to contrasting sites.
33
Avila, Manuel. "Optimisation de modèles markoviens pour la reconnaissance de l'écrit." Rouen, 1996. http://www.theses.fr/1996ROUES034.
Full textAbstract:
Cette thèse traite de l'optimisation de modèles markoviens dédiés à la reconnaissance de textes manuscrits, dans le cas particulier d'une application à vocabulaire réduit : la lecture des montants littéraux de chèques. Le premier chapitre décrit brièvement les techniques utilisées pour la reconnaissance de l'écrit. Nous présentons également les descriptions des mots que nous avons utilisées. Le second chapitre présente les modèles de Markov cache. Nous présentons notamment les différents niveaux de représentation du problème de la lecture de l'écrit dans le cas de modélisations markoviennes : les niveaux phrase, mot et lettre. Finalement, nous présentons les algorithmes couramment utilisés pour exploiter des modèles de Markov : les algorithmes de Viterbi et de Baum-welch, avec des variantes que nous avons adaptées à nos besoins. Dans le troisième chapitre, nous traitons du problème d'une optimisation des descriptions des mots. Nous donnons trois méthodes de représentation des mots. Nous présentons ensuite une méthode de recherche de l'ordre optimal d'un processus de Markov basée sur la minimisation de critères d'information de type Akaike soit AIC, BIC etc. Finalement, nous comparons les résultats des trois alphabets pour les ordres de 1 à 3. Ceci nous permet de valider le choix de la description des mots et de l'ordre du modèle de Markov correspondant. Nous réutilisons ces résultats au chapitre 4. Dans ce chapitre, trois approches sont proposées pour la reconnaissance des mots : la première est une approche globale qui par définition ne s'attache pas à l'identification des lettres, la seconde est une approche analytique basée sur une modélisation complètement explicitée, la troisième méthode est une approche pseudo-analytique intermédiaire entre les deux approches précédentes. Elle modélise le mot de manière analytique en utilisant des modèles globaux de lettres. Finalement, les résultats de ces trois méthodes sont ensuite fusionnés : chapitre 5. Ce chapitre traite de l'identification des montants littéraux de chèques. La stratégie développée se décompose en trois parties : validation de la segmentation des mots, identification des mots et reconstitution de la phrase. A chaque partie correspond une modélisation markovienne adaptée.
34
Serpa, Barboza Andrea Keylin. "Los efectos de la diversificación de la cartera de préstamos en el rendimiento y riesgo del sistema bancario peruano." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653937.
Full textAbstract:
El objetivo de este estudio es analizar el impacto de la diversificación sobre el rendimiento y el riesgo. Se emplea un panel de datos de frecuencia mensual para el periodo 2010-2019 y se utiliza el estimador de MGM por la naturaleza dinámica del modelo. Los resultados muestran que la diversificación de la cartera de préstamos no tiene efecto en el rendimiento del sistema bancario, sin embargo, se observa que los bancos con mayores riesgos pueden aumentar sus rendimientos si aumentan su nivel de concentración por sector económico y departamento. El efecto en el riesgo dependerá del tipo de concentración, un mayor nivel de concentración de préstamos por sector y departamento disminuirá el riesgo crediticio; pero una mayor concentración de préstamos por tipo de crédito aumentará el nivel de riesgo. Además, se observó que no hay ningún efecto sobre el riesgo ni el rendimiento dependiendo de si el banco es de capitales domésticos o extranjeros. Los hallazgos son importantes para los bancos al elegir su estrategia crediticia y clave para las autoridades regulatorias.The objective of this study is to analyze the impact of diversification on performance and risk. A monthly frequency data panel is used for the period 2010-2019 and the MGM estimator is used because of the dynamic nature of the model. The results show that loan portfolio diversification does not affect the performance of the banking system, however, it is observed that banks with higher risks can increase their returns by increasing their level of concentration by economic sector and department. The effect on risk will depend on the type of concentration, a higher level of loan concentration by sector and department will decrease credit risk; but a higher concentration of loans by type of credit will increase the level of risk. Besides, it was noted that there is no effect on risk or return depending on whether the bank is domestic or foreign-owned. The findings are important for banks when choosing their credit strategy and key for regulatory authorities.
Trabajo de investigación
35
Borea, Anna Elisabetta. "il fenomeno dell'entanglement quantistico e suoi possibili riscontri in astrofisica." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18768/.
Full textAbstract:
Il lavoro presentato si apre con una descrizione dei postulati della MQ al fine dell'introduzione delle particelle correlate o entangled.Sono messi in evidenza i tratti caratteristici del fenomeno ed i mezzi fisici per lo studio dello stesso.Si pone l'attenzione anche sul percorso storico che ha portato alla completa verifica teorica e sperimentale dell'entanglement.La tesi si chiude con l'introduzione di particolari regioni astrofisiche al fine di studiare un articolo presentato da J.Gomez che lega il fenomeno alle regioni presentate.
36
COSTA, Washington César de Almeida. "Análise dinâmica não linear de sinais de voz para detecção de patologias laríngeas." Universidade Federal de Campina Grande, 2012. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1416.
Full textAbstract:
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-08-13T16:22:35Z
No. of bitstreams: 1
WASHINGTON CÉSAR DE ALMEIDA COSTA - TESE PPGEE 2012..pdf: 6463355 bytes, checksum: 40d8703ef8a6dd3ef05acde3025cf628 (MD5)Made available in DSpace on 2018-08-13T16:22:35Z (GMT). No. of bitstreams: 1 WASHINGTON CÉSAR DE ALMEIDA COSTA - TESE PPGEE 2012..pdf: 6463355 bytes, checksum: 40d8703ef8a6dd3ef05acde3025cf628 (MD5) Previous issue date: 2012-11-09
Patologias na laringe podem afetar a qualidade vocal, prejudicando a comunicação humana. As técnicas objetivas tradicionais para o diagnóstico dessas patologias fazem uso de exames considerados invasivos, causando certo desconforto ao paciente. Análise acústica, utilizando técnicas de processamento digital de sinais de voz, pode ser utilizada para o desenvolvimento de ferramentas não invasivas de auxílio ao diagnóstico de patologias laríngeas. A precisão do diagnóstico, contudo, depende da escolha das características e parâmetros da fala que melhor representem a desordem vocal provocada por uma determinada patologia. Este trabalho trata da caracterização e da classificação de sinais de vozes saudáveis e vozes afetadas por diferentes patologias laríngeas (edema, paralisia e nódulos nas pregas vocais), por meio da análise dinâmica não linear (e teoria do caos), como também por meio da análise de quantificação de recorrência. No processo de caracterização é investigado, por meio de testes estatísticos, o potencial de cada característica em discriminar os tipos de sinais de voz considerados. Para a classificação é empregada a técnica de análise discriminante com as funções linear ou quadrática, com validação cruzada, sendo considerado um intervalo de confiança de 95% para as médias das taxas de acuraria do classificador. A partir da combinação de características dos conjuntos das medidas de análise não linear (MNL) e das medidas de quantificação de recorrência (MQR), as médias da taxa de acurácia obtidas variaram nos intervalos de confiança: [95,44%; 100%) para a classificação entre vozes saudáveis e patológicas; [94,75%; 100%] entre vozes saudáveis e afetadas por edema, e entre saudáveis e nódulos. Para a classificação entre saudável e paralisia, obteve-se uma acurácia de 100% . Também são avaliados os efeitos do uso de vetores híbridos formados por características MNL, MQR e coeficientes extraídos da análise preditiva linear (LPC). Neste caso. as taxas de acurácia variaram nos intervalos de confiança: [95,02%; 97,62%] na discriminação entre vozes afetadas por paralisia e edema; [98,29%; 99,93%] para paralisia versus nódulos e [97,98%; 99,84%] para edema versus nódulos. Os resultados encontrados indicam que o método utilizado é promissor, podendo ser empregado no desenvolvimento de uma ferramenta computacional para apoio ao diagnóstico de patologias laríngeas.
Laryngeal pathologies may affect the voice quality, harniing human communication. The traditional objective techniques for diagnosing these pathologies make use of exams, considered invasive, causing discomfort to the patient. Acoustic analysis, using digital speech signal processing techniques. can be used for the development of non-invasive tools in order to aid laryngeal diseases diagnosis. The accuracy of diagnosis, however. depends on the choice of parameters and the speech characteristics diat better represent the voice disorder caused by a given pathology. This work deals with the characterization and classification of healthy voice signals and voices affecied by different laryngeal diseases (edema, paralysis and vocal fold nodules), by means of nonlinear dynamic analysis (and chãos theory) as well as recurrence quantification analysis. In the characterization process, the potential of each feature is investigated to discriminate the types of voice signals considered, by means of statistical tests. For the classification, the technique of discriminam analysis is employed with linear or quadratic functions, with cross-validation. A 95% confidence levei was considered for the average of accuracy rates of the classifier performance. From the feature combination of the set of nonlinear analysis measures (MNL) and the quantification recurrence measures (MQR). the average of accuracy rates varied in the following confidence intervals: [95.44%; 100%] for healthy and pathologícal classification: [94.75%; 100%] between healdiy and edema voices, and also between healthy and nodules. The accuracy rate was 100% between healthy and paralysis. We also evaluated the effects of using hybrid vectors formed by MNL, MQR and linear predictive coding (LPC) coefficients. In this case, the accuracy rates ranged in the confidence intervals: [95.02%; 97.62%] in the paralysis versus edema voices discrimination; [98.29%; 99.93%] for paralysis versus nodules and [97.98%; 99.84%] for edema versus nodules. Obtained results indicate that the used method is promising and it can even be used to develop a computational tool to support diagnosis of laryngeal diseases.
37
Kaced, Tarik. "Partage de secret et théorie algorithmique de l'information." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2012. http://tel.archives-ouvertes.fr/tel-00763117.
Full textAbstract:
Notre travail sur le partage de secret se base sur les points de vue de la Théorie de l'Information de Shannon et de la Complexité de Kolmogorov. Nous allons expliquer comment ces trois sujets sont intimement liés. Les inégalités d'information jouent un rôle central dans cette thèse: ce sont les inégalités pour l'entropie de Shannon, qui correspondent également aux inégalités valides pour la complexité de Kolmogorov. La Théorie Algorithmique de l'Information introduite par Kolmogorov formalise l'idée d'aléatoire pour les chaînes de caractères. Ce sont là deux raisons justifiant à elles seules la notion de partage de secret algorithmique dans le cadre de la Théorie Algorithmique de l'information (si l'on sait partager un secret aléatoire, on peut partager n'importe quel secret). Originalement étudié par sa définition combinatoire, le partage de secret a été plus tard généralisé par une formulation dans le langage de la théorie de l'information. Cette étape a permis l'utilisation des inégalités d'information, et s'est révélée très importante dans la caractérisation de l'efficacité des schémas de partage de secret. L'étude de ces inégalités n'en est qu'à ses débuts. Nous y contribuons en introduisant la notion d'inégalité essentiellement conditionnelle, qui montre une fois de plus que ces inégalités ne sont pas encore complètement comprises.
38
Lapuyade-Lahorgue, Jérôme. "Sur diverses extensions des chaînes de Markov cachées avec application au traitement des signaux radar." Phd thesis, Institut National des Télécommunications, 2008. http://tel.archives-ouvertes.fr/tel-00473711.
Full textAbstract:
L'objectif de cette thèse est de proposer différents modèles généralisant le modèle classique des chaînes de Markov cachées à bruit indépendant couramment utilisé en inférence bayésienne de signaux. Les diverses extensions de ce modèle visent à l'enrichir et à prendre en compte différentes propriétés du signal, comme le caractère non gaussien du bruit, ou la nature semi-markovienne du signal caché. Dans un problème d'inférence bayésienne, nous disposons de deux processus aléatoires X et Y , on observe la réalisation y de Y et nous estimons la réalisation cachée x de X. Le lien existant entre les deux processus est modélisé par la distribution de probabilité p(x, y). Dans le modèle classique des chaînes de Markov cachées à bruit indépendant, la distribution p(x) est celle d'une chaîne de Markov et la distribution p(y|x) est celle de marginales indépendantes conditionnellement à x. Bien que ce modèle puisse être utilisé dans de nombreuses applications, il ne parvient pas à modéliser toutes les situations de dépendance. Le premier modèle que nous proposons est de type “chaînes de Markov triplet”, on considère ainsi un troisième processus U tel que le triplet (X, U, Y ) soit une chaîne de Markov. Dans le modèle proposé, ce processus auxiliaire modélise la semi-markovianité de X ; on parvient ainsi à prendre en compte la non markovianité éventuelle du processus caché. Dans un deuxième modèle, nous considérons des observations à dépendance longue et nous proposons un algorithme d'estimation original des paramètres de ce modèle. Nous étudions par ailleurs différents modèles prenant en compte simultanément la semi-markovianité des données cachées, la dépendance longue dans les observations ou la non stationnarité des données cachées. Enfin, la nature non nécessairement gaussienne du bruit est prise en compte via l'introduction des copules. L'intérêt des différents modèles proposés est également validé au travers d'expérimentations. Dans la dernière partie de cette thèse, nous étudions également comment la segmentation obtenue par une méthode bayésienne peut être utilisée dans la détection de cibles dans le signal radar. Le détecteur original que nous implémentons utilise la différence de statistiques entre un signal recu et les signaux recus de son voisinage. Le détecteur ainsi implémenté s'avère donner de meilleurs résultats en présence de fort bruit que le détecteur habituellement utilisé en traitement radar.
39
JAIN, PARTH. "LANDSLIDE SUSCEPTIBILITY MAPPING USING GIS BASED PROBABILISTIC APPROACHES IN KALIMPONG AND DARJEELING, WEST BENGAL, INDIA." Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/20084.
Full textAbstract:
In West Bengal, India's Darjeeling Kalimpong area, landslides are a serious concern. With
the use of four GIS-based techniques, including the Shannon Entropy (SE), Statistical Index
Method (SIM), and Weight-of-Evidence (WoE), this study attempts to create an extensive
map of landslip susceptibility. These techniques were chosen because they are good at
managing huge datasets, tolerating various factors, and giving reliable estimates of landslip
vulnerability. The research area was split into two parts: the first was for training the models, and the second was for model validation. A total of 13 conditioning factors were chosen and
examined for their impact on the likelihood of landslides, including elevation, slope, aspect, curvature, distance from rivers, roads, and lineaments, lithology, land use/cover, stream
power index, topographic wetness index, rainfall, and geology. Each strategy was put into
practise, and the resulting maps of landslip susceptibility were compared and assessed. The
analysis's findings demonstrated that all four models were useful for estimating the likelihood
of landslides, with the SI, and WoE models performing somewhat better than the SE model. The Receiver Operating Characteristic (ROC) curve was used to evaluate the models' accuracy, and it revealed that the SI, SE, and WoE models had AUC values of 0.826, 0.77, and 0.825, respectively. The landslip inventory data was used to evaluate and validate the
landslip susceptibility maps produced by the four models. The comparison revealed that for
predicting landslip susceptibility, the SI and WoE models performed better than the SE model. This work provides useful data for land use planning and disaster management in the study
region and shows the efficiency of GIS-based models in landslip susceptibility mapping.
40
周三童. "Estimation of Shannon Entropy in Quadrat Sampling." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/78336941155413575763.
Full text
41
"On the relation between the Shannon entropy and the von Neumann entropy." 2003. http://library.cuhk.edu.hk/record=b5891654.
Full textAbstract:
Ho Siu-wai.Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references (leaves 103-104).
Abstracts in English and Chinese.
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Classical Information Theory --- p.2
Chapter 1.1.1 --- Shannon Entropy --- p.3
Chapter 1.1.2 --- "Shannon Joint Entropy, Conditional Entropy, Mutual Information and Conditional Mutual Information" --- p.5
Chapter 1.1.3 --- Applications of Shannon Entropy --- p.7
Chapter 1.2 --- Mathematical background for Quantum Mechanics --- p.8
Chapter 1.2.1 --- Dirac Notation --- p.8
Chapter 1.2.2 --- Linear Operators and Matrices --- p.11
Chapter 1.2.3 --- Spectral Decomposition and Diagonalization --- p.11
Chapter 1.2.4 --- Functions of Normal Matrices --- p.12
Chapter 1.2.5 --- Trace --- p.13
Chapter 1.2.6 --- Kronecker Product --- p.13
Chapter 1.3 --- Elementary Quantum Mechanics --- p.14
Chapter 1.3.1 --- State Space --- p.15
Chapter 1.3.2 --- Evolution --- p.16
Chapter 1.3.3 --- Quantum Measurements --- p.17
Chapter 1.3.4 --- Joint Systems --- p.20
Chapter 1.3.5 --- Quantum Mixtures --- p.22
Chapter 1.3.6 --- Subsystems --- p.28
Chapter 1.4 --- von Neumann Entropy --- p.31
Chapter 1.4.1 --- Definition --- p.32
Chapter 1.4.2 --- Applications of the von Neumann Entropy --- p.34
Chapter 1.4.3 --- Conditional Entropy --- p.34
Chapter 1.5 --- Organization of The Thesis --- p.36
Chapter Chapter 2 --- Problem Formulations --- p.38
Chapter 2.1 --- Measurements that Produce Pure States --- p.39
Chapter 2.2 --- The Shannon Entropy of a Quantum States --- p.41
Chapter 2.3 --- An Equivalent Density Matrix Obtained by Mixing Orthogonal States --- p.44
Chapter Chapter 3 --- Pure Post-Measurement States (PPMS) Measurements --- p.46
Chapter 3.1 --- Introduction --- p.46
Chapter 3.2 --- Definition of PPMS measurements --- p.46
Chapter 3.3 --- Properties of PPMS Measurement --- p.52
Chapter 3.4 --- An Alternative Definition of von Neumann entropy in terms of PPMS Measurements --- p.73
Chapter Chapter 4 --- Mental Measurement of a Quantum State --- p.75
Chapter 4.1 --- Introduction --- p.75
Chapter 4.2 --- An Alternative Definition of a Projective Measurement --- p.76
Chapter 4.3 --- Characteristics of a Projective PPMS Measurement --- p.81
Chapter 4.4 --- The Choice of the Mental Measurement --- p.84
Chapter 4.5 --- An Alternative Definition of von Neumann Entropy by Means of a Mental Measurement --- p.86
Chapter 4.6 --- Construction of the Mental Measurement --- p.86
Chapter Chapter 5 --- Completeness of Density Matrix Postulate --- p.92
Chapter 5.1 --- Introduction --- p.92
Chapter 5.2 --- Complete Specification of Quantum Ensemble by Density Matrix --- p.93
Chapter 5.3 --- An Alternative Definition of von Neumann Entropy by Shannon Entropy --- p.98
Chapter Chapter 6 --- Conclusion and Future Works --- p.99
Chapter 6.1 --- Conclusion --- p.99
Chapter 6.2 --- Future Work --- p.101
Reference --- p.103
42
Bodvin, Joanna Sylvia Liesbeth. "Bayesian estimation of Shannon entropy for bivariate beta priors." Diss., 2010. http://hdl.handle.net/2263/26191.
Full textAbstract:
Having just survived what is arguably the worst financial crisis in time, it is expected that the focus on regulatory capital held by financial institutions such as banks will increase significantly over the next few years. The probability of default is an important determinant of the amount of regulatory capital to be held, and the accurate calibration of this measure is vital. The purpose of this study is to propose the use of the Shannon entropy when determining the parameters of the prior bivariate beta distribution as part of a Bayesian calibration methodology. Various bivariate beta distributions will be considered as priors to the multinomial distribution associated with rating categories, and the appropriateness of these bivariate beta distributions will be tested on default data. The formulae derived for the Bayesian estimation of Shannon entropy will be used to measure the certainty obtained when selecting the prior parameters.Dissertation (MSc)--University of Pretoria, 2010.
Statistics
unrestricted
43
Liaw, Dah-Jing, and 廖大經. "Estimation and Simulation Study of the Shannon''s Entropy Index." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/23323791673283504067.
Full text
44
Dukkipati, Ambedkar. "On Generalized Measures Of Information With Maximum And Minimum Entropy Prescriptions." Thesis, 2006. https://etd.iisc.ac.in/handle/2005/353.
Full textAbstract:
Kullback-Leibler relative-entropy or KL-entropy of P with respect to R defined as ∫xlnddPRdP , where P and R are probability measures on a measurable space (X, ), plays a basic role in the
definitions of classical information measures. It overcomes a shortcoming of Shannon entropy – discrete case definition of which cannot be extended to nondiscrete case naturally. Further, entropy and other classical information measures can be expressed in terms of KL-entropy and
hence properties of their measure-theoretic analogs will follow from those of measure-theoretic KL-entropy. An important theorem in this respect is the Gelfand-Yaglom-Perez (GYP) Theorem which equips KL-entropy with a fundamental definition and can be stated as: measure-theoretic KL-entropy equals the supremum of KL-entropies over all measurable partitions of X . In this thesis we provide the measure-theoretic formulations for ‘generalized’ information measures, and
state and prove the corresponding GYP-theorem – the ‘generalizations’ being in the sense of R ´enyi and nonextensive, both of which are explained below.
Kolmogorov-Nagumo average or quasilinear mean of a vector x = (x1, . . . , xn) with respect to a pmf p= (p1, . . . , pn)is defined ashxiψ=ψ−1nk=1pkψ(xk), whereψis an arbitrarycontinuous and strictly monotone function. Replacing linear averaging in Shannon entropy with Kolmogorov-Nagumo averages (KN-averages) and further imposing the additivity constraint – a characteristic property of underlying information associated with single event, which is logarithmic – leads to the definition of α-entropy or R ´enyi entropy. This is the first formal well-known generalization of Shannon entropy. Using this recipe of R´enyi’s generalization, one can prepare only two information measures: Shannon and R´enyi entropy. Indeed, using this formalism R´enyi
characterized these additive entropies in terms of axioms of KN-averages. On the other hand, if one generalizes the information of a single event in the definition of Shannon entropy, by replacing the logarithm with the so called q-logarithm, which is defined as lnqx =x1− 1 −1 −q , one gets
what is known as Tsallis entropy. Tsallis entropy is also a generalization of Shannon entropy but it does not satisfy the additivity property. Instead, it satisfies pseudo-additivity of the form x ⊕qy = x + y + (1 − q)xy, and hence it is also known as nonextensive entropy. One can apply
R´enyi’s recipe in the nonextensive case by replacing the linear averaging in Tsallis entropy with KN-averages and thereby imposing the constraint of pseudo-additivity. A natural question that
arises is what are the various pseudo-additive information measures that can be prepared with this recipe? We prove that Tsallis entropy is the only one. Here, we mention that one of the important characteristics of this generalized entropy is that while canonical distributions resulting from ‘maximization’ of Shannon entropy are exponential in nature, in the Tsallis case they result in power-law distributions.
The concept of maximum entropy (ME), originally from physics, has been promoted to a general principle of inference primarily by the works of Jaynes and (later on) Kullback. This connects information theory and statistical mechanics via the principle: the states of thermodynamic equi-
librium are states of maximum entropy, and further connects to statistical inference via select the probability distribution that maximizes the entropy. The two fundamental principles related to the concept of maximum entropy are Jaynes maximum entropy principle, which involves maximizing Shannon entropy and the Kullback minimum entropy principle that involves minimizing relative-entropy, with respect to appropriate moment constraints.
Though relative-entropy is not a metric, in cases involving distributions resulting from relative-entropy minimization, one can bring forth certain geometrical formulations. These are reminiscent of squared Euclidean distance and satisfy an analogue of the Pythagoras’ theorem. This property
is referred to as Pythagoras’ theorem of relative-entropy minimization or triangle equality and plays a fundamental role in geometrical approaches to statistical estimation theory like information geometry. In this thesis we state and prove the equivalent of Pythagoras’ theorem in the
nonextensive formalism. For this purpose we study relative-entropy minimization in detail and present some results.
Finally, we demonstrate the use of power-law distributions, resulting from ME-rescriptions
of Tsallis entropy, in evolutionary algorithms. This work is motivated by the recently proposed generalized simulated annealing algorithm based on Tsallis statistics.
To sum up, in light of their well-known axiomatic and operational justifications, this thesis establishes some results pertaining to the mathematical significance of generalized measures of information. We believe that these results represent an important contribution towards the ongoing
research on understanding the phenomina of information.
(For formulas pl see the original document)
ii
45
Dukkipati, Ambedkar. "On Generalized Measures Of Information With Maximum And Minimum Entropy Prescriptions." Thesis, 2006. http://hdl.handle.net/2005/353.
Full textAbstract:
Kullback-Leibler relative-entropy or KL-entropy of P with respect to R defined as ∫xlnddPRdP , where P and R are probability measures on a measurable space (X, ), plays a basic role in the
definitions of classical information measures. It overcomes a shortcoming of Shannon entropy – discrete case definition of which cannot be extended to nondiscrete case naturally. Further, entropy and other classical information measures can be expressed in terms of KL-entropy and
hence properties of their measure-theoretic analogs will follow from those of measure-theoretic KL-entropy. An important theorem in this respect is the Gelfand-Yaglom-Perez (GYP) Theorem which equips KL-entropy with a fundamental definition and can be stated as: measure-theoretic KL-entropy equals the supremum of KL-entropies over all measurable partitions of X . In this thesis we provide the measure-theoretic formulations for ‘generalized’ information measures, and
state and prove the corresponding GYP-theorem – the ‘generalizations’ being in the sense of R ´enyi and nonextensive, both of which are explained below.
Kolmogorov-Nagumo average or quasilinear mean of a vector x = (x1, . . . , xn) with respect to a pmf p= (p1, . . . , pn)is defined ashxiψ=ψ−1nk=1pkψ(xk), whereψis an arbitrarycontinuous and strictly monotone function. Replacing linear averaging in Shannon entropy with Kolmogorov-Nagumo averages (KN-averages) and further imposing the additivity constraint – a characteristic property of underlying information associated with single event, which is logarithmic – leads to the definition of α-entropy or R ´enyi entropy. This is the first formal well-known generalization of Shannon entropy. Using this recipe of R´enyi’s generalization, one can prepare only two information measures: Shannon and R´enyi entropy. Indeed, using this formalism R´enyi
characterized these additive entropies in terms of axioms of KN-averages. On the other hand, if one generalizes the information of a single event in the definition of Shannon entropy, by replacing the logarithm with the so called q-logarithm, which is defined as lnqx =x1− 1 −1 −q , one gets
what is known as Tsallis entropy. Tsallis entropy is also a generalization of Shannon entropy but it does not satisfy the additivity property. Instead, it satisfies pseudo-additivity of the form x ⊕qy = x + y + (1 − q)xy, and hence it is also known as nonextensive entropy. One can apply
R´enyi’s recipe in the nonextensive case by replacing the linear averaging in Tsallis entropy with KN-averages and thereby imposing the constraint of pseudo-additivity. A natural question that
arises is what are the various pseudo-additive information measures that can be prepared with this recipe? We prove that Tsallis entropy is the only one. Here, we mention that one of the important characteristics of this generalized entropy is that while canonical distributions resulting from ‘maximization’ of Shannon entropy are exponential in nature, in the Tsallis case they result in power-law distributions.
The concept of maximum entropy (ME), originally from physics, has been promoted to a general principle of inference primarily by the works of Jaynes and (later on) Kullback. This connects information theory and statistical mechanics via the principle: the states of thermodynamic equi-
librium are states of maximum entropy, and further connects to statistical inference via select the probability distribution that maximizes the entropy. The two fundamental principles related to the concept of maximum entropy are Jaynes maximum entropy principle, which involves maximizing Shannon entropy and the Kullback minimum entropy principle that involves minimizing relative-entropy, with respect to appropriate moment constraints.
Though relative-entropy is not a metric, in cases involving distributions resulting from relative-entropy minimization, one can bring forth certain geometrical formulations. These are reminiscent of squared Euclidean distance and satisfy an analogue of the Pythagoras’ theorem. This property
is referred to as Pythagoras’ theorem of relative-entropy minimization or triangle equality and plays a fundamental role in geometrical approaches to statistical estimation theory like information geometry. In this thesis we state and prove the equivalent of Pythagoras’ theorem in the
nonextensive formalism. For this purpose we study relative-entropy minimization in detail and present some results.
Finally, we demonstrate the use of power-law distributions, resulting from ME-rescriptions
of Tsallis entropy, in evolutionary algorithms. This work is motivated by the recently proposed generalized simulated annealing algorithm based on Tsallis statistics.
To sum up, in light of their well-known axiomatic and operational justifications, this thesis establishes some results pertaining to the mathematical significance of generalized measures of information. We believe that these results represent an important contribution towards the ongoing
research on understanding the phenomina of information.
(For formulas pl see the original document)
ii
46
Santos, Micael João da Silva. "Uso da entropia de Shannon para classificação de zonas artificiais ou naturais em imagens." Master's thesis, 2013. http://hdl.handle.net/10400.6/3700.
Full textAbstract:
A identificação de zonas naturais e artificiais em imagens é muito útil para um conjunto de procedimentos, em particular na área do Ambient Assisted Living (AAL), por exemplo em sistemas de vídeo vigilância. Com a massificação das tecnologias é relativamente simples obter uma câmara de vídeo digital (por exemplo uma webacam), sendo por isso fácil implementar um sistema de vídeo vigilância que permita obter informações adicionais e importantes para a monitorização em AAL. Neste trabalho pretende-se elaborar uma aplicação que efetue a vigilância de espaços ao ar livre, com vista a identificação de subconjuntos estáticos, sendo estes naturais ou artificiais. A identificação dos subconjuntos estáticos baseia-se num algoritmo desenvolvido calculando entropia de uma dada imagem, que em vez de um varrimento linear efetua o cálculo de uma forma espacial, tirando partidodainformaçãodaáreacircundanteparasermaisconsistente. Associadaà análise encontra-se uma especificação do ambiente de operabilidade do sistema, permitindo assim o enriquecimento dos testes efetuados.The identification of natural and artificial areas in images is very useful for a group of procedures, particularly in the area of Ambient Assisted Living (AAL), for example in video surveillance systems. With the massification of technology is relatively simple to get a digital video camera (eg webacam), so it is easy to implement a video surveillance system that allows additional information and important for monitoring in AAL. In this work intended to develop an application that performs surveillance of outdoor spaces, in order to identifying subsets static, being these natural or artificial. The identification of static subsets is based on a algorithm developed by calculating entropy of a particular image, as instead of a linear sweep performs the calculation of a spatial form, taking advantage of the surrounding area information to be more consistent.Associated to the analysis is a specification of the environment operability of the system, allowing enrichment of the tests performed.
47
Ijaz, Ali Z. "Taxonomic and environmental annotation of bacterial 16S rRNA gene sequences via Shannon entropy and database metadata terms." Thesis, 2017. http://hdl.handle.net/1959.7/uws:47536.
Full textAbstract:
Microbial ecology seeks to describe the diversity and distribution of microorganisms in various habitats within the context of environmental variables. High throughput sequencing has greatly boosted the number and scope of projects aiming to study and analyse these organisms, with ever-increasing amounts of data being generated. Amplicon based taxonomic analysis, which determines the presence of microbial taxa in different environments on the basis of marker gene annotations, often uses percentage identity as the main metric to determine sequence similarity against databases. This data is then used to study the distribution of biodiversity as well as the response of microbial communities to stressors. However, the 16S rRNA gene displays varying degrees of sequence conservation along its length and is therefore prone to provide different results depending on the part of 16S rRNA gene used for sequencing and analysis. Furthermore, sequence alignment is primarily performed using the popular BLAST sequence alignment tool, which incurs a great computational performance penalty although newer, more efficient tools are being developed. A new approach that is fast and more accurate is critically needed to process the avalanche of data. Additionally, repositories of environmental metadata can provide contextual information to sequence annotations, potentially enhancing analysis if they can be incorporated into bioinformatics pipelines. The overarching aim of this work was to enhance the taxonomic annotation of bacterial sequences by developing a weighted scheme that utilizes inherent evolutionary conservation in the bacterial 16S rRNA gene sequences and by adding contextual, environmental information pertaining to these sequences in a systematic fashion.
48
May, John, Hannes Leo, and Alfred Taudes. "Evaluation of E-Participation Efficiency with Biodiversity Measures - the Case of the Digital Agenda Vienna." 2015. http://epub.wu.ac.at/4479/1/Final_version.pdf.
Full textAbstract:
We introduce the Effective Number of Issues measure for e-participation efficiency. This novel index is based on the Shannon entropy measure of biodiversity and summarizes the amount of information gained through an e-participation project in one number. This makes the comparison between different e-participation projects straightforward and lays the foundation for the rigorous analysis of success factors of e-participation projects in a data-driven way. After providing the formula and rationale for the new measure we use the ENI index to benchmark the idea generation process for the digital agenda Vienna against other projects. It turns out that the efficiency of this project is significantly higher than those observed for other cases. We conjecture that this can be attributed to the user-friendly design of the software platform and the effective communication strategy of the process management. Finally, suggestions for further research are given. (authors' abstract)
49
周欣穎. "Estimation of Shannon's Entropy and Hill's Family of Indices in One Community." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/75192106315484591171.
Full text
50
Ευθυμίου, Κωνσταντίνος. "On the assessment of manufacturing systems complexity." Thesis, 2013. http://hdl.handle.net/10889/6381.
Full textAbstract:
Objective of the present study is the development of methods for the assessment of
manufacturing systems complexity and the investigation of flexibility and complexity
relationship. Towards this target, a complete approach based on information theory
permitting the analytical, quantitative and systematic modeling and quantification of both
static and dynamic manufacturing complexity is proposed. Static complexity concerns the
structure of the manufacturing systems, namely the products, the processes, the resources that
constitute the systems as well as their interconnections. Static complexity is treated as the
information that is required for the description of a manufacturing system. Multi domain
matrices modeling the relationships between products, processes and resources are formalized
as networks following the notions of graph theory. The information content of each matrix is
assessed employing Shannon entropy measure and their aggregation yields the static
complexity. Dynamic complexity is related to the uncertainty in the behaviour of a
manufacturing system and in the present study is associated with the unpredictability of the
performance indicators timeseries. The unpredictability of the performance indicators
timeseries, which are provided by computer simulation, is captured employing the Lempel
Ziv algorithm that calculates the Kolmogorov complexity. The dynamic complexity is either
the unpredictability of a specific timeseries or the weighted mean of a series of performance
indicators timeseries produced under different product demand scenarios. The relationship
between flexibility and complexity is investigated for a group of 19 different configurations of
a manufacturing system. In particular, operation flexibility that refers to the system’s ability
to produce a set of products through different machines, materials, operations and sequences
of operations and total complexity, and both static and dynamic are examined employing a
utility function. As a case study, two assembly lines producing three car floor model types at
three different product mixes are investigated. The dynamic complexity of each assembly
line is assessed and the relationship between product mix and dynamic complexity is studied.
The evaluation of the case study revealed the efficiency of the suggested approach validated
its applicability to industrial environments.Αντικείμενο της παρούσας διατριβής είναι η ανάπτυξη μεθόδων για την εκτίμηση πολυπλοκότητας συστημάτων παραγωγής και η διερεύνηση της σχέσης ευελιξίας και πολυπλοκότητας. Προς αυτή την κατεύθυνση προτείνεται μια ολοκληρωμένη προσέγγιση βασισμένη στην θεωρία της πληροφορίας που επιτρέπει μια αναλυτική, ποσοτικοποιημένη και συστηματική προτυποποίηση και εκτίμηση τόσο της στατικής όσο και της δυναμικής πολυπλοκότητας των συστημάτων παραγωγής. Η στατική πολυπλοκότητα αφορά την δομή των συστημάτων παραγωγής, και σχετίζεται με τα προϊόντα, τις διεργασίες, τους παραγωγικούς πόρους που αποτελούν το σύστημα καθώς και τις μεταξύ τους σχέσεις. Η στατική πολυπλοκότητα αντιμετωπίζεται ως η πληροφορία που απαιτείται για να περιγραφεί ένα σύστημα παραγωγής. Πολυ-πεδιακοί πίνακες αναπαριστούν τις σχέσεις μεταξύ προϊόντων, διεργασιών και πόρων και προτυποποιούνται ως δίκτυα ακολουθώντας την θεωρία γράφων. Το πληροφοριακό περιεχόμενο κάθε πίνακα εκτιμάται με την χρήση της εντροπίας Shannon και το άθροισμα για όλους τους πίνακες δίνει την στατική πολυπλοκότητα. Η δυναμική πολυπλοκότητα σχετίζεται με την αβεβαιότητα της συμπεριφοράς των συστημάτων παραγωγής και στην παρούσα διατριβή συνδέεται με την απροβλεψιμότητα των χρονοσειρών δεικτών απόδοσης ενός συστήματος. Οι χρονοσειρές των δεικτών απόδοσης προκύπτουν από υπολογιστική προσομοίωση και η απροβλεψιμότητα τους εκτιμάται με των αλγόριθμο Lempel Ziv ο οποίος υπολογίζει την πολυπλοκότητα Kolmogorov. Η δυναμική πολυπλοκότητα είναι η απροβλεψιμότητα είτε μιας συγκεκριμένης χρονοσειράς είτε ο σταθμισμένος μέσος όρος ενός συνόλου χρονοσειρών δεικτών απόδοσης. Η σχέση ευελιξίας – πολυπλοκότητας διερευνάται για 19 διαμορφώσεις ενός συστήματος παραγωγής. Συγκεκριμένα, η ευελιξία λειτουργίας που αναφέρεται στην ικανότητα ενός συστήματος να παράγει ένα σύνολο προϊόντων χρησιμοποιώντας διαφορετικές μηχανές και διεργασίες και πολυπλοκότητα τόσο η στατική όσο και η δυναμική μελετώνται με μια συνάρτηση χρησιμότητας. Ως περίπτωση μελέτης εξετάζονται δύο γραμμές συναρμολόγησης που παράγουν τρία δάπεδα αμαξιού σε τρία μείγματα παραγωγής. Η δυναμική πολυπλοκότητα κάθε γραμμής και η σχέση μείγματος παραγωγής και δυναμικής πολυπλοκότητα μελετώνται. Η αξιολόγηση της περίπτωσης μελέτης αποδεικνύει την αποτελεσματικότητα των προτεινόμενων μεθόδων σε βιομηχανικό περιβάλλον.