Добірка наукової літератури з теми "APD topology"

Conventional designs of an avalanche photodiode (APD) have been based on a planar p–n junction since the 1960s. APD developments have been driven by the necessity to provide a uniform electric field over the active junction area and to prevent edge breakdown by special measures. Most modern silicon photomultipliers (SiPM) are designed as an array of Geiger-mode APD cells based on planar p–n junctions. However, the planar design faces an inherent trade-off between photon detection efficiency and dynamic range due to loss of an active area at the cell edges. Non-planar designs of APDs and SiPMs have also been known since the development of spherical APDs (1968), metal-resistor-semiconductor APDs (1989), and micro-well APDs (2005). The recent development of tip avalanche photodiodes (2020) based on the spherical p–n junction eliminates the trade-off, outperforms the planar SiPMs in the photon detection efficiency, and opens new opportunities for SiPM improvements. Furthermore, the latest developments in APDs based on electric field-line crowding and charge-focusing topology with quasi-spherical p–n junctions (2019–2023) show promising functionality in linear and Geiger operating modes. This paper presents an overview of designs and performances of non-planar APDs and SiPMs.

Free space optics is a technology which uses beam of light to provide optical connection for transmitting and receiving purposes. For the increasing demand for high bandwidth in different network topology, FSO links has been a solution to the connectivity bottleneck problem. Transmitter consists of NRZ modulating CW laser with the link range 1 km in the wavelength 1310 nm or 1550 nm. When the signal is transmitted in the channel, the performance could be severely degrated due to atmospheric attenuation and earth inequalities. The purpose of this paper is to find a suitable filter for any of the two receivers i.e APD and PIN for the reduction of noise. Filters used are low pass Bessel filter, low pass butterworth filter, low pass Chebyshev filter.

ABSTRAK Penggunaan aplikasi EDMS di project office PT PHE ONWJ dinilai masih belum optimal karena masih lambat dalam pengunaan aplikasi EDMS. Oleh karena itu dilakukanlah penelitian ini dengan tujuan untuk mengoptimalkan jaringan yang digunakan untuk mengakses aplikasi EDMS pada project office PT PHE ONWJ. Pengoptimalan jaringan yang dimaksud adalah dengan membangun topologi di project office PT PHE ONWJ dan menerapkan metro sebagai perantara topologi star di project office dan topologi star dikantor pusat sehingga menciptakan topologi hybrid. Topologi hybrid yang dimaksud adalah penggabungan antara topologi star yang ada di jaringan pusat, metro sebagai perantara kantor pusat dengan project office PT PHE ONWJ dan topologi star yang akan dibangun di project office PT ONWJ. Diharapkan setelah menerapkan topologi yang telah dirancang dapat mengoptimalkan penggunaan aplikasi EDMS. Topologi star di project office PT ONWJ dan metro sebagai perantara 2 topologi kantor pusat dan project office menghasilkan topologi hybrid. Kesimpulan dari penelitian ini adalah penerapan topologi dalam jaringan dapat memberikan optimalisasi dibandingkan dengan tanpa menerapkan topologi. Hasil rata-rata ping saat pengaksesan aplikasi EDMS sebelum menerapkan topologi hybrid mendapatkan hasil sebesar 392,98 ms dan setelah menerapkan topologi hybrid mendapatkan hasil sebesar 143,50 ms, sehingga disimpulkan bahwa penerapan topologi hybrid lebih baik dalam menjalankan aplikasi EDMS. ABSTRACT The use of EDMS application in PT PHE ONWJ project office is considered not optimal because it is still slow in the use of EDMS applications. Therefore this study was conducted with the aim to optimize the network used to access the EDMS application on the PT PHE ONWJ project office. Network optimization in question is to build a topology in the project office of PT PHE ONWJ and apply the metro as an intermediate star topology in the project office and star topology at the headquarters so as to create a hybrid topology. Hybrid topology in question is a merger between the star topology in the central network, metro as an intermediary head office with PT PHE ONWJ project office and star topology to be built at PT ONWJ project office. It is expected that after applying the topology that has been designed to optimize the use of EDMS applications. Star topology in PT ONWJ project office and metro as intermediary 2 topology headquarters and project office produce hybrid topology. The conclusion of this research is application of topology in network can give optimization compared with without applying topology. The average result of ping when accessing EDMS application before applying hybrid topology got 392.98 ms result and after applying hybrid topology get result of 143,50 ms, so it is concluded that application of hybrid topology is better in running EDMS application. How To Cite : Widodo, C. Yana, M. Agung, H. (2018). IMPLEMENTASI TOPOLOGI HYBRID UNTUK PENGOPTIMALAN APLIKASI EDMS PADA PROJECT OFFICE PT PHE ONWJ. Jurnal Teknik Informatika, 11(1), 19-30. doi 10.15408/jti.v11i1.6472 Permalink/DOI: http://dx.doi.org/10.15408/jti.v11i1.6472

Abtrak: Topologi merupakan cabang ilmu matematika yang mempelajari suatu struktur yang terdapat pada himpunan. Seperti halnya himpunan hingga yang memiliki kardinalitas, maka topologi hingga juga memiliki kardinalitas. Jika himpunan memiliki kardinalitas dan topologi pada S, maka kardinalitas dari yang dinotasikan dengan menyetakan banyaknya elemen dari . Jika topologi pada S, maka matriks keterhubungan langsung topologi adalah matriks berukuran yang dinotasikan dengan . Matriks merupakan matriks yang elemennya 0 atau 1. Kata Kunci: Himpunan, Kardinalitas, Matriks Keterhubungan Langsung, Topologi. Abstract: Topology is a branch of mathematics which study structures on a set. As a finite set, a finite topology have a cardinality. Let be a finite set with cardinality and let be a topology on S, then the cardinality of which denotes is the number of elements . If topology on S, then the corresponding matrix to a topology is a matrix which denoted by . is the matrix have element 0 or 1. Keywords: Cardinality, Set, The Corresponding Matrix, Topology,

BackgroundTumor explant models provide a powerful ex vivo tool to evaluate complex biological mechanisms in a controlled environment. Ex vivo models retain much of the original tumor biology, heterogeneity, and tumor microenvironment, and therefore provide a useful preclinical platform and functional approach to assess drug responses rapidly and directly.MethodsTo explore mechanisms of resistance to cancer immunotherapy, we established an organotypic tissue slice Air-Liquid Interface (ALI) ex vivo system utilizing surgical tumor specimens from patients to assess the impact of the clinically utilized anti-PD-1 antibody nivolumab (OPDIVO). In the present study, we built a real-world patient cohort comprised of six tumor types: non-small cell lung cancer, melanoma, pancreatic ductal adenocarcinoma, breast cancer, prostate cancer, and colorectal cancer. We assessed tissue morphology, histology, PD-L1 IHC (CPS and TPS), CD8 T cell topology, proliferation in the tumor and stromal compartments, and secretome profiling.ResultsOur tumor slice model highly recapitulated features of the original tumor, including tumor architecture, immune phenotypes, and the prognostic markers. To identify responses to aPD-1 treatment, we compared baseline values for the cultured tumor slices with values at different timepoints post treatment. Secretome profiling of tissue explant supernatants using a panel of 94 analytes, revealed alterations to cytokines produced in the tumor microenvironment in response to aPD-1 treatment. We found that soluble expression patterns were associated with T-cell patterns (inflamed, excluded and desert) and PD-L1 score (CPS and TPS) in tumor tissues. These cytokines mediate critical functions across the immune cell cycle. Ongoing efforts to characterize T cell activation, exhaustion, tumor intrinsic responses and microenvironment composition using Imaging Mass Cytometry will be presented.ConclusionsIn this study, we demonstrated the feasibility of using fresh, surgically resected human tumors to test aPD-1 responses in an ex vivo system. Further, this model system has the potential to drive discovery and translational efforts by evaluating mechanisms of resistance to cancer immunotherapy and evaluate new single agent or combination therapies in the ex vivo setting.

ABSTRAKDengan menerapkan sistem multihop pada jaringan sensor nirkabel, pembacaan kondisi lingkungan dapat dilakukan pada lingkungan yang lebih luas. Pada penelitian ini, sistem multihop jaringan sensor nirkabel menggunakan platform IoT NodeMCU V3 yang memiliki modul Wi-Fi ESP8266. Jumlah sensor node yang digunakan merupakan batas maksimal client yang dapat terhubung kepada Wi-Fi ESP8266, yaitu 1 sink node dan 4 sensor node. Sensor node akan mengirimkan datanya kepada sink node, kemudian data tersebut akan dikirimkan kepada website untuk ditampilkan pada dashboard Adafruit.io. Pengiriman data diuji menggunakan 2 topologi yaitu bus dan tree. Berdasarkan hasil pengujian, jarak maksimal pengiriman data pada topologi bus tanpa penghalang adalah 72 meter dengan delay pengiriman 64 detik dan topologi tree adalah 108 meter dengan delay pengiriman 14 detik. Sistem multihop pada topologi bus dan tree dapat mengirim data dengan 2 penghalang yang memiliki ketebalan 15 cm dengan delay pengiriman 29 detik pada topologi bus dan 14 detik pada topologi tree.Kata kunci: jaringan sensor nirkabel, multihop, Wi-Fi, NodeMCU V3 ABSTRACTBy applying a multihop system on wireless sensor network, reading environment condition can be done in wider environment. In this study, multihop system in wireless sensor network uses IoT NodeMCU V3 platform which has a Wi-Fi ESP8266 module. The amount of node sensor is the maximum limit of client which can be linked to Wi-Fi access point in Wi-Fi ESP8266 module, i.e 1 sink node and 4 sink node. The node sensor will transfer the data to the sink node, then the data will be transfered to the website to be shown on Adafruit.io dashboard. The transmission data is tested using 2 topologies, i.e bus and tree. Based on the test, the maximum distance of data transmission in bus topology without barrier is 72 meters with delivery delay which takes 64 seconds and in tree topology is 108 seconds with delivery delay which takes 14 seconds. The multihop system in the bus topology and the tree topology can send the data with 2 barriers which has 15 cm width and delivery delay among the nodes which takes 29 seconds in bus topology and 14 seconds in tree topology.Keywords: wireless sensor network, multihop, Wi-Fi, NodeMCU V3

Mémoire rédigé en vue de l'obtention de l'habilitation à diriger les recherches. Il donne un résumé de mon activité de recherche (anneaux de Chow, classes de Stiefel-Whitney, algèbres de Hopf, entrelacs, K-théorie de Milnor).

La integració de tots els components bàsics per a la generació, manipulació i detecció de llum en xips òptics està impulsant avenços científics i tecnològics, per exemple, en el desenvolupament de tecnologies de la informació o de dispositius de detecció per a les tecnologies quàntiques. Degut a la seva flexibilitat, escalabilitat i la possibilitat d’observar directament l’evolució de la funció d’ona utilitzant senzilles tècniques de tractament d’imatges, les estructures fotòniques integrades són una plataforma ideal per a la simulació quàntica, és a dir, per emular fenòmens quàntics que apareixen en altres branques de la física. A més, aquestes analogies òptiques-quàntiques també permeten dissenyar circuits fotònics integrats amb propietats excepcionals. En aquesta tesi aprofitem propietats no trivials de la física quàntica per dissenyar nous dispositius fotònics integrats amb funcionalitats avançades i rendiments millorats, així com nous simuladors fotònics. Específicament, explotem les similituds entre les equacions de Helmholtz i de Schrödinger, que permeten reproduir la dinàmica temporal d’una partícula atrapada en un potencial periòdic amb l’evolució espacial de la llum propagant-se en guies d’ona acoblades, per aplicar transformacions supersimètriques i processos adiabàtics així com explorar geometries topològiques no trivials en sistemes de guies d’ona òptiques acoblades. En aquesta línia, la primera part de la tesi està dedicada a introduir els conceptes físics i matemàtics que descriuen les guies d’ona òptiques acoblades, les analogies òptiques-quàntiques i la supersimetria en òptica. La segona part de la tesi engloba el disseny de nous dispositius fotònics integrats combinant l’aplicació de transformacions supersimètriques per manipular modes espacials amb tècniques de passatge adiabàtic per introduir la robustesa. Primer presentem un nou mètode per a la multiplexació de modes espacials basat en guies d’ona supersimetriques, que filtren els modes, en combinació amb la tècnica de passatge adiabàtic espacial que es fa servir per transmetre eficient i robustament els modes escollits entre guies. De manera similar, mantenint-nos en la idea d’aplicar protocols d’enginyeria quàntica per dissenyar nous dispositius fotònics amb rendiments millorats, proposem connectar de manera adiabàtica estructures supersimètriques al llarg de la distància de propagació. En particular, aquesta tècnica l’utilitzem per dissenyar guies d’ona còniques, filtres de modes, divisors de feixos i interferòmetres, eficients i robustos. Finalment, la tercera part de la tesi està dedicada a la simulació de diferents fenòmens quàntics utilitzant sistemes fotònics. Per començar aquesta part, explorem els efectes que les transformacions supersimètriques indueixen en sistemes amb propietats topologies no trivials, les quals estan intrínsecament lligades a les simetries internes del sistema. Amb aquest objectiu, considerem el sistema més simple amb propietats topològiques no trivials i demostrem en sistemes de guies d’ona acoblades com la protecció topològica d’un estat pot ser suspesa i restablerta utilitzant transformacions supersimètriques. A més, per accedir a aquestes fases topològiques no trivials, un element clau és la introducció de camps artificials gauge (AGF) que controlen la dinàmica de partícules no carregades que d’una altra manera eludeixen la influència dels camps electromagnètics estàndards. En aquesta línia, investiguem la possibilitat d’induir AGF utilitzant llum amb moment orbital angular en comptes de manipular la geometria del sistema. Específicament, mesurem l’efecte de gàbia d’Aharonov-Bohm que està lligat amb la presència d’un camp magnètic. Aquesta tècnica permet accedir a diferent règims topològics en una sola estructura, un pas important per a la simulació quàntica utilitzant sistemes fotònics.
La integración de todos los componentes básicos para la generación, manipulación y detección de luz en chips ópticos está impulsando avances científicos y tecnológicos, por ejemplo, en el desarrollo de tecnologías de la información o en los dispositivos de detección para las tecnologías cuánticas. Debido a su flexibilidad, escalabilidad y a la posibilidad de observar directamente la evolución de la función de onda utilizando senzillas técnicas de trata, las estructuras fotónicas son ideales para la simulación cuántica, es decir, para emular fenómenos cuánticos que aparecen en otras ramas de la física. Es más, estas analogías ópticas-cuánticas también permiten diseñar nuevos circuitos fotónicos integrados con propiedades excepcionales. En esta tesis, aprovechamos propiedades no triviales que emergen de la física cuántica para diseñar nuevos dispositivos fotónicos integrados con funcionalidades avanzadas y rendimientos mejorados, así como nuevos simuladores fotónicos. Específicamente, explotamos las similitudes entre las ecuaciones de Helmholtz y de Schrödinger, que permiten reproducir la dinámica temporal de una particula atrapada en un potencial periódico con la evolución espacial de la luz propagándose en guías de onda, para aplicar transformaciones supersimétricas y procesos adiabáticos así como explorar geometrías topológicas no triviales en sistemas de guías de onda ópticas acopladas. La primera parte de la tesis está dedicada a introducir los conceptos matemáticos y físicos que describen las guías de onda ópticas acopladas, las analogías ópticas-cuánticas y la supersimetria óptica. La segunda parte de la tesis engloba el diseño de nuevos dispositivos fotónicos integrados basados en combinar transformaciones supersimétricas para manipular los modos espaciales con las técnicas adiabáticas para introducir robustez. Primero presentamos un nuevo método para la multiplexación de modos espaciales basado en guías de onda supersimétricas, que filtran los modos, en combinación con la técnica de pasaje adiabático espacial que se usa para transmitir de manera eficiente y robusta los modos escogidos entre guías. De manera similar, manteniéndonos en la idea de aplicar protocolos de ingeniería cuántica para diseñar nuevos dispositivos fotónicos con rendimientos superiores, proponemos conectar de manera adiabática estructuras supersimétricas a lo largo de la propagación. En particular, ésta técnica la utilizamos para diseñar guías de onda cónicas, filtros modales, divisores de haz e interferómetros. Finalmente, la tercera parte de la tesis está dedicada a la simulación de diferentes fenómenos físicos utilizando sistemas fotónicos. Para empezar, exploramos los efectos que las transformaciones supersimétricas inducen en sistemas con propiedades topológicas no triviales, las cuales están intrínsecamente ligadas a las simetrías internas del sistema. Con este objetivo, consideramos el sistema más simple con propiedades topológicas no triviales y demostramos en un sistema de guías de onda acopladas cómo la protección topológica de un estado puede ser suspendida y restablecida utilizando transformaciones supersimétricas. Además, para acceder a las fases topológicas no triviales, un elemento clave es la introducción de campos artificiales de gauge (AGF) que controlan la dinámica de partículas no cargadas que de otra manera eluden la influencia de los campos electromagnéticos. Es esta línea, investigamos la posibilidad de inducir AGF utilizando luz con momento orbital angular en lugar de manipular la geometría del sistema. Específicamente, medimos el fenómeno de jaula de Aharonov-Bohm que está ligado a la presencia de un campo magnético sintético. Esta técnica permite acceder a diferentes regímenes topológicos en una sola estructura, un paso importante para la simulación cuántica utilizando sistemas fotónicos.
The integration of all the basic components for light generation, manipulation and detection in optical chips is boosting scientific and technological advances, for instance, in the development of information technology and data communications or of sensing devices for quantum technologies. Due to its flexibility, scalability and of the possibility of directly observing the wavefunction evolution using simple imaging techniques, integrated photonic structures are an ideal playground for quantum simulation i.e., for emulating quantum phenomena appearing in other branches of physics. Moreover, these quantum-optical analogies also allow to design novel integrated photonic circuits with exceptional properties. In this context, in this thesis we harness non-trivial properties stemming from quantum physics to design novel integrated photonic devices with advanced functionalities and enhanced performances as well as to engineer novel photonic simulators. Specifically, we exploit the similarities between the Helmholtz and the Schrödinger equations, which allow to mimic the temporal dynamics of a single particle trapped in a lattice potential with the spatial evolution of a light beam propagating in an array of optical waveguides, to apply supersymmetric (SUSY) transformations and adiabatic passage processes as well as to explore non-trivial topological geometries in systems of coupled optical waveguides. In this vein, the first part of the thesis is devoted to introduce the mathematical concepts and physical ideas behind coupled optical waveguides, quantum-optical analogies and optical SUSY. After that, the second part of the thesis encompasses the design of novel integrated photonic devices by combining the spatial modal content manipulation offered by SUSY transformations with the robustness supplied by adiabatic passage techniques. In this regard, we start by presenting a novel method for mode division (de)multiplexing rooted on SUSY waveguides, which provide the mode filtering capabilities, in combination with a Spatial Adiabatic Passage protocol, which is used to efficiently and robustly transfer the desired modes between waveguides. Similarly, keeping on the idea of applying quantum engineering protocols to design novel photonic devices with enhanced performances, we also propose to connect, in an adiabatic fashion, SUSY structures along the propagation direction. In particular, this technique is used to engineer efficient and robust tapered waveguides, mode filters, beam splitters and interferometers. Finally, the third part of the thesis is dedicated to the photonic simulation of different phenomena. We explore first the effect that SUSY transformations induce in systems with non-trivial topological properties, which are intrinsically connected with the system's internal symmetries. To this aim, we consider the simplest system with non-trivial topological properties and demonstrate in waveguide arrays how the topological protection of a targeted state can be suspended and reestablished by applying SUSY transformations. Moreover, to access these non-trivial topological phases, a key step is the introduction of Artificial Gauge Fields (AGF) controlling the dynamics of uncharged particles that otherwise elude the influence of standard electromagnetic fields. To this end, we investigate the possibility of inducing AGF by injecting light beams carrying Orbital Angular Momentum, rather than manipulating the geometry of the system. Specifically, we measure the Aharonov-Bohm caging effect, which is directly related with the presence of a synthetic magnetic flux, in an array of coupled optical waveguides. This technique paves the way towards accessing different topological regimes in one single structure, representing an important step forward for quantum simulation in photonic structures.

This PhD thesis is the result of our research on duality theory and completions for partially ordered sets. A first main aim of this dissertation is to propose different kind of topological dualities for some classes of partially ordered sets and a second aim is to try to use these dualities to obtain completions with nice properties. To this end, we intend to follow the line of the classical dualities for bounded distributive lattices due to Stone and Priestley. Thus, we will need to consider a notion of distributivity on partially ordered sets. Also we propose a topological duality for the class of all partially ordered sets and we use this duality to study some properties of partially ordered sets like its canonical extension, order-preserving maps and the extensions of n-ary maps that are order-preserving in each coordinate. Moreover, to attain these aims we will study the partially ordered sets from an algebraic point of view.
Esta tesis doctoral es el resultado de nuestra investigación sobre la teoría de la dualidad y completaciones de conjuntos parcialmente ordenados. Un primer objetivo general de este trabajo es proponer diferentes tipos de dualidades topológicas para algunas clases de conjuntos parcialmente ordenados y un segundo objetivo es tratar de utilizar estas dualidades para obtener diferentes completaciones con buenas propiedades. Para este fin, nos proponemos seguir la línea de las dualidades clásicas para retículos distributivos acotados debidas a Stone y a Priestley. Por lo tanto, necesitaremos considerar una noción de distributividad sobre conjuntos parcialmente ordenados. También proponemos una dualidad topológica para la clase de todos los conjuntos parcialmente ordenados y usamos esta dualidad para estudiar algunas propiedades de los conjuntos parcialmente ordenados como su extensión canónica, funciones que preservan orden y las extensiones de funciones n-arias que preservan orden en cada coordenada. Por otra parte, para alcanzar estos objetivos vamos a estudiar los conjuntos parcialmente ordenados desde un punto de vista algebraico.

In the last years, there has been done research in using topology as a new tool for studying data sets, typically high dimensional data. These studies have brought new methods for qualitative analysis, simplification, and visualization of high dimensional data sets. One good example, where these methods are useful, is in the study of microarray data (DNA data). To be able to use these methods, one needs to acquire knowledge of different topics in topology. In this paper we introduce simplicial homology, persistent homology, Mapper, and some simplicial complex constructions.

Today there is an immense production of data, and the need for better methods to analyze data is ever increasing. Topology has many features and good ideas which seem favourable in analyzing certain datasets where statistics is starting to have problems. For example, we see this in datasets originating from microarray experiments. However, topological methods cannot be directly applied on finite point sets coming from such data, or atleast it will not say anything interesting. So, we have to modify the data sets in some way such that we can work on them with the topological machinery. This way of applying topology may be viewed as a kind of discrete version of topology. In this thesis we present some ways to construct simplicial complexes from a finite point cloud, in an attempt to model the underlying space. Together with simplicial homology and persistent homology and barcodes, we obtain a tool to uncover topological features in finite point clouds. This theory is tested with a Java software package called JPlex, which is an implementation of these ideas. Lastly, a method called Mapper is covered. This is also a method for creating simplicial complexes from a finite point cloud. However, Mapper is mostly used to create low dimensional simplicial complexes that can be easily visualized, and structures are then detected this way. An implementation of the Mapper method is also tested on a self made data set.

This thesis is devoted to the study of the effect of Legendrian surgery on contact manifolds. In particular, we study the effect of this surgery on the Reeb dynamics of the contact manifold on which we perform such a surgery along Legendrian links. We obtain an exact sequence of cyclic Legendrian homology for the Legendrian links. Then we present the applications in 3-dimension and higher dimensions.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Un réseau mobile ad hoc (Mobile Ad hoc Network, MANET) est un réseau sans fil, formé dynamiquement par un ensemble d'utilisateurs équipés de terminaux mobiles, sans l'utilisation d'une infrastructure préexistante, ou d'une administration centralisée. Les équipements utilisés dans les MANETs sont limités par la capacité de la batterie, la puissance de calcul et la bande passante. Les utilisateurs des MANETs sont libres de se déplacer, ce qui induit à des topologies dynamiques dans le temps. Toutes ces contraintes ajoutent plus de challenges aux protocoles et services de communications afin de fonctionner dans les MANETs. L'évolution des réseaux de 4ème génération (4G) est appelée à intégrer les MANETs avec les autres types de réseaux afin d'étendre leurs portées. Nous nous sommes intéressés dans la première partie de cette thèse à quelques challenges connus dans les MANETs en proposant des solutions novatrices utilisant des propriétés intéressantes des topologies de graphes. Dans un premier temps, nous avons effectué une étude sur la prédiction de la mobilité afin de maintenir une topologie d'ensemble dominant connecté dans les MANETs. Nous avons proposé dans un autre travail comment construire des topologies de graphes ayant des propriétés globales en se basant seulement sur des informations locales des nœuds mobiles. Ces topologies servent comme overlay aux MANETs. Nous avons proposé des algorithmes distribués pour construire des alliances offensives et défensives globales minimales. Nous avons aussi défini des heuristiques pour ces algorithmes afin de réduire les tailles des alliances obtenues. La première partie de cette thèse est achevée par la proposition d'un framework pour la conception et l'analyse des protocoles de contrôle de topologie dans les MANETs. Nous avons identifié les points communs des algorithmes de contrôle de topologie conçus pour les réseaux mobiles ad hoc et nous avons enrichi le simulateur NS-2 avec un ensemble d'extensions pour supporter le contrôle de topologie
We are interested in this thesis to graph-based approaches to deal with some challenges in networking, namely, graph topologies of mobile ad hoc networks (MANETs) and process model matchmaking in large scale web service. We propose in the first part: (1) a generic mechanism using mobility information of nodes to maintain a graph topology of the network. We show particularly, how to use the prediction of future emplacements of nodes to maintain a connected dominating set of a given MANET. (2) distributed algorithms to construct minimal global offensive alliance and global defensive alliance sets in MANETs. We also introduce several heuristics to get a better approximation of the cardinality of the alliance sets which is a desirable property for practical considerations. (3) a framework to facilitate the design and evaluation of topology control protocols in MANETs. We propose in the framework, a common schema for topology control based on NS-2 simulator and inspired from the commonalities between the components of the topology control algorithms in MANETs. In the second part, we focus on process model matchmaking. We propose two graph-based solutions for process model inexact matching to deal with high computational time of existing work in the literature. In the first solution, we decompose the process models into their possible execution sequences. After, we propose generic graph techniques using string comparator metrics for process model matchmaking based on this decomposition. In order to get better optimization of the execution time and to deal with process model matching in large scale web services, the second solution combines a spectral graph matching with structural and semantic proposed approaches. This solution uses an eigen-decomposition projection technique that makes the runtime faster

In order to utilise network resources efficiently, we need a strong knowledge of how the resources are shared and provisioned. However,this information is often unavailable due to the complexity of modern networks, the restrictive access to information describing their configurations and accuracy/reliability issues regarding information provisioning methods. Here, we propose the concept of functional topologies to deduce how resources are shared between different traffic flows. A functional topology describes the dependencies between traffic flows as a graph of interactions; this is in contrast to typical network graphs that model the physical connections between network components (routers and hosts). Unlike other work relying on in-network data, this topology is constructed solely at end hosts by measuring interdependencies of traffic flows via cross-correlation analysis. In order to measure the complete sets of interdependencies of traffic flows, different time intervals are used for sampling time series data. It is shown that these time intervals are related to maximum delays of traffic flows in network. The results of cross-correlation analysis are validated using well-known inverse participation ratio (IPR). As a part of the validation process, the results are analysed and compared with dominant/important flows of the network obtained by a new technique that uses eigen decomposition and spanning tree algorithm. The methodology of measuring interdependencies of traffic flows is validated and evaluated using real world data from a sensor network,as well as detailed simulation modelling different network topologies e.g. local area network. All the dependency measurements of traffic flow results are fed into a novel algorithm to construct functional topology of the network. Result shows that the algorithm constructs accurate functional topology of the network. Functional topology simplifies network topology by considering only nodes that create dependencies among traffic flows. With the help of this topology, end hosts can gain insight into resource provisioning of a network without requiring ISP assistance.