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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

以BDI代理人架構為基礎於網路虛擬社群 之群體犯罪偵測 / A BDI-based Collective Crime Detection Service for Virtual Community

莊竣丞, Jhuang, Jyun Cheng Unknown Date (has links)
本論文所定義之「網路群體犯罪」,不同於組織犯罪般有結構的犯罪團體,亦非為了追求共同利益而合作的共犯夥伴,而是網路使用者自發性互動行為下逐漸浮現的群體近似犯罪行為,並且普遍存在於當今各式各樣的網際網路社群,以各種不同的樣貌與形式展現。本研究以Sutherland(1978)提出之差別接觸理論與Bandura(1977)提出之社會學習理論為基礎,運用理論相關的元素與概念作為食材與食譜,以BDI代理人模式為方法來設計網路群體犯罪之模擬模式,透過動態模擬群體犯罪在不同條件下展現不同之面貌。更運用Watts(2003)主張的網路科學概念與分析方法,來分析犯罪關係網絡之特性,本研究藉由控制網路社群之使用者人數(Size)與初始犯罪率(ICR)來觀察不同組合之下所演化的網路結構差異,並從四個衡量指標:犯罪技能平均數、群聚係數、前10%使用者平均連結度、連結度小於10之比率,標示演化之網路結構的特徵。研究結果發現:1. 犯罪技能擴散的速度受到ICR高低的影響,當ICR越高的時候犯罪技能擴散的速度越快,反之,當ICR較低的時候犯罪技能擴散速度隨之減緩。2. 當ICR超越某一特定臨界值之後,使用者擁有的犯罪技能平均數與所屬社群人數成正向關係。3. ICR的高低對於群聚係數的高低有反向關係,當ICR越高則群聚係數越低,反之,當ICR越低時群聚係數越高。4. 社群使用者人數越多的情況下,群聚係數越低。5. 前10%使用者的平均連結度有隨著演化次數逐漸增加的趨勢。6. 初始犯罪率的高低與前10% 使用者的平均連結度成反比關係。7. 不論演化次數、社群人數多寡與初始犯罪率值之高低,均僅有少數犯罪者擁有高度的連結,絕大多數的使用者或犯罪者其連結度數均不高(符合power law分佈)。 / Collective crime is an emerging phenomenon along with collective intelligence in recent years. It is defined as a form of universally distributed crime originated from spontaneous interaction among community users in this paper. The issues that collective crime addresses focus on deviant or criminal behavior existing in common groups or crowds rather than traditional topics at computer crime or cybercrime. The theories, “differential association” proposed by criminologist Sutherland(1978) and “social learning” proposed by sociologist Bandura(1977), underpin the explanation of collective crime phenomena and the model design of agent-based simulation. The detection function of collective crime consists of the evolving network function based on the micro-simulation and an analysis of the function along with four indicators: average amount of crime skills, average cluster coefficient, average degree of top 10% users, and rate of users with degrees smaller than 10. The research findings are: 1. A community with higher initial crime rate (ICR) results in faster spreading of crime skills. 2. A negative relationship between the community size and the average amounts of crime skills exists, as ICR exceeds a threshold. 3. As ICR gets increasing, the average cluster coefficient gets decreasing, and vice versa. 4. The average cluster coefficient gets decreasing along with increasing community size. 5. The average degree of top 10% users gets increasing along time. 6. A negative relationship exists between ICR and the average degree of the top 10% users. 7. The distribution of the degrees of community users follows the scale-free power law distribution – whatever the network evolution times, community size and ICR are, most of the community users have fewer degrees and only few criminals have pretty high degrees relatively.
62

Analysis, structure and organization of complex networks / Analyse, structure et organisation des réseaux complexes

Zaidi, Faraz 25 November 2010 (has links)
La Science des réseaux est apparue comme un domaine d'étude fondamental pour modéliser un grand nombre de systèmes synthétiques ou du monde réel.La découverte du graphe petit monde et du graphe sans échelle dans ces réseaux a révolutionné la façon d'étudier, d'analyser, de modéliser et de traiter ces réseaux. Dans cette thèse, nous nous intéressons à l'étude des réseaux ayant ces propriétés et souvent qualifiés de réseaux complexes.A notre avis, les recherches menées dans ce domaine peuvent être regroupées en quatre catégories: l'analyse, la structure, le processus/organisation et la visualisation.Nous abordons des problèmes relatifs à chacune de ces catégories tout au long de cette thèse. (...) / Network science has emerged as a fundamental field of study to model many physicaland real world systems around us. The discovery of small world and scale free propertiesof these real world networks has revolutionized the way we study, analyze, model andprocess these networks. In this thesis, we are interested in the study of networks havingthese properties often termed as complex networks. In our opinion, research conducted inthis field can be grouped into four categories, Analysis, Structure, Processes-Organizationand Visualization. We address problems pertaining to each of these categories throughoutthis thesis. (...)
63

NETWORK ANALYTICS FOR THE MIRNA REGULOME AND MIRNA-DISEASE INTERACTIONS

Nalluri, Joseph Jayakar 01 January 2017 (has links)
miRNAs are non-coding RNAs of approx. 22 nucleotides in length that inhibit gene expression at the post-transcriptional level. By virtue of this gene regulation mechanism, miRNAs play a critical role in several biological processes and patho-physiological conditions, including cancers. miRNA behavior is a result of a multi-level complex interaction network involving miRNA-mRNA, TF-miRNA-gene, and miRNA-chemical interactions; hence the precise patterns through which a miRNA regulates a certain disease(s) are still elusive. Herein, I have developed an integrative genomics methods/pipeline to (i) build a miRNA regulomics and data analytics repository, (ii) create/model these interactions into networks and use optimization techniques, motif based analyses, network inference strategies and influence diffusion concepts to predict miRNA regulations and its role in diseases, especially related to cancers. By these methods, we are able to determine the regulatory behavior of miRNAs and potential causal miRNAs in specific diseases and potential biomarkers/targets for drug and medicinal therapeutics.
64

Human Mobility and Infectious Disease Dynamics / How modern mobility data enhances epidemic control

Schlosser, Frank 02 August 2023 (has links)
Die Covid-19 Pandemie hat gezeigt, wie stark die Ausbreitung von Infektionskrankheiten von der Dynamik der menschlichen Mobilität bestimmt wird. Gleichzeitig eröffnet die anhaltende Explosion an verfügbaren Mobilitätsdaten im 21. Jahrhundert einen viel genaueren Blick auf die menschliche Mobilität. In dieser Arbeit untersuchen wir verschiedene Ansätze, wie moderne Mobilitätsdaten zusammen mit Modellierung ein tieferes Verständnis des Zusammenspiels von menschlicher Mobilität und der Ausbreitung von Infektionskrankheiten ermöglichen. Wir verwenden Mobilitätsdaten um zu zeigen, dass landesweite Mobilitätsmuster während der Covid-19 Pandemie in Deutschland komplexe strukturelle Veränderungen durchlaufen haben. Wir stellen einen räumlich heterogenen Rückgang der Mobilität während Lockdown-Phasen fest. Vor allem beobachten wir, dass ein deutlicher Rückgang der Fernreisen während der Pandemie zu einem lokaleren Netzwerk und einer Abschwächung des “Small-World”-Effekts führt. Wir zeigen, dass diese strukturellen Veränderungen einen erheblichen Einfluss auf die Ausbreitungsdynamik von Epidemien haben, indem sie die epidemische Kurve abflachen und die Ausbreitung in geografisch weit entfernte Regionen verzögern. Des Weiteren entwickeln wir eine neue Methode zur Bestimmung des Ausbruchsursprungs anhand von hochaufgelösten geografischen Bewegungsdaten. Abschließend untersuchen wir, wie repräsentativ Mobilitätsdatensätze für das tatsächliche Reiseverhalten einer Bevölkerung sind. Wir identifizieren verschieden Arten von Verzerrungen, zeigen ihre Spuren in empirischen Datensätzen, und entwickeln einen mathematischen Rahmen um diese Verzerrungen abzuschwächen. Wir hoffen, dass unsere Studien in dieser Arbeit sich als hilfreiche Bausteine erweisen für ein einheitliches Verständnis von menschlicher Mobilität und der Dynamik von Infektionskrankheiten. / The Covid-19 pandemic demonstrated how strongly infectious disease spread is driven by the dynamics of human mobility. At the same time, the ongoing explosion of available mobility data in the 21st century opens up a much finer view of human mobility. In this thesis, we investigate several ways in which modern mobility data sources and modeling enable a deeper understanding of the interplay of human mobility and infectious disease spread. We use large-scale mobility data captured from mobile phones to show that country-wide mobility patterns undergo complex structural changes during the Covid-19 pandemic in Germany. Most prominently, we observe that a distinct reduction in long-distance travel during the pandemic leads to a more local, clustered network and a moderation of the “small-world” effect. We demonstrate that these structural changes have a considerable effect on epidemic spreading processes by “flattening” the epidemic curve and delaying the spread to geographically distant regions. Further, we show that high-resolution mobility data can be used for early outbreak detection. We develop a novel method to determine outbreak origins from geolocated movement data of individuals affected by the outbreak. We also present several practical applications that have been developed based on the above research. To further explore the question of applicability, we examine how representative mobility datasets are of the actual travel behavior of a population. We develop a mathematical framework to mitigate these biases, and use it to show that biases can severely impact outcomes of dynamic processes such as epidemic simulations, where biased data incorrectly estimates the severity and speed of disease transmission. We hope that our studies in this thesis will prove as helpful building blocks to assemble the emerging, unified understanding of mobility and infectious disease dynamics.
65

Art en réseaux : la structure des réseaux comme une nouvelle matrice pour la production des œuvres artistiques / Art & Networks : networks structure as a new matrix for the production of artworks

Souliotou, Anastasia Zoé 19 May 2015 (has links)
La problématique de ce doctorat est : comment la structure des réseaux constitue une nouvelle matrice pour la production d’oeuvres artistiques. Pour répondre à cette question, nous commencerons en étudiant l’évolution de la notion de « réseau » de l’antiquité jusqu’à aujourd’hui ; les théories des réseaux concernant leur structure et/ou leur dynamique. Ensuite nous présenterons les applications –de la notion ou des théories de réseaux– tant dans les sciences que dans l’art. Nous listerons et nous analyserons huit types de réseaux et puis nous mentionnerons des oeuvres artistiques qui ont été inspirées par ces types de réseaux et/ou qui utilisent certains (types de) réseaux comme matrice pour leur création. Nous proposerons le projet Lignes Imaginaires, un modèle 3D qui se fonde sur la conception d’un métro de lignes imaginaires, voire de lignes dynamiques et/ou paradoxales qui sont en mouvement, apparaissent/disparaissent, créent de l’infrastructure supplémentaire. L’analyse du métro Lignes Imaginaires dévoile l'importance de la géographie et de la spatialité des réseaux, tandis que leur représentation graphique topologique reste insuffisante pour la représentation précise et pour la compréhension de leur structure (paradoxale). En outre, l’innovation du métro Lignes Imaginaires est que son infrastructure est dynamique et auto-organisée, contrairement aux métros traditionnels où les lignes et leurs itinéraires sont fixes. L’objectif du projet artistique Lignes Imaginaires est de visualiser un concept en créant un métro hors du commun qui pourrait aussi proposer des formes alternatives des réseaux de transports dans le contexte urbain. / This thesis examines and shows ways in which the structure of networks can provide a new matrix for the production of artworks. In order to answer this question we start by studying: the evolution of the term ‘network’ from the ancient times up to nowadays; the theories that refer to network structure or network dynamics. Then we present the applications of these theories into both art and science. We list and analyze eight different types of networks and then we feature artworks which have been inspired by these network types or have used the network structure of a certain type as a matrix for art making. We propose the Imaginary Lines project, a three-dimensional network model which is based on the concept of a metro composed of imaginary lines. More precisely Imaginary Lines metro network encompasses seven paradoxical lines which move, (dis)appear and produce supplementary infrastructure. The Imaginary Lines metro unveils the importance of geography and spatiality, in contrast with topological network graphic representations, which remain insufficient, in terms of utmost accuracy in representation and comprehension of network structure. Additionally, the Imaginary Lines network innovation lays in its infrastructure dynamics as well as in its self-organisation. The objective of the Imaginary Lines artistic project is to visualise a concept by creating an unusual metro, which goes beyond traditional fixed-route transport networks and can support alternative forms of urban transport development.

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