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Nayati, Mohammed Abdul Khader. "School bus routing and scheduling using GIS." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-547.
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School bus routing and scheduling are among the major problems because school bus transportation needs to be safe, reliable and efficient. Hence, the research question for this thesis is to answer how to transport students in the safest, most economical and convenient manner. The objective of this thesis is to create a GIS based school transport management system which helps in bus-stop allocation, design fastest and safest bus routes with AVL facility. This thesis also aims to investigate how a school transportation management system may improve the transportation security. The result from this study has helped to develop a school bus routing and scheduling prototype model for Sujatha High School, Hyderabad. This prototype model will help the school transportation management to design shortest and fastest school bus routes and they can also allocate bus stops, which will help them in selecting the pick-up stops for the students and staff, according to their concentration in the areas. This thesis has also, through literature study, investigated how a school transport management system can improve the transportation security. For the time being, there is a general belief that ICT contributes to improving the security, although a quantification of such improvements are lacking. The user interface application has been developed by using VBA and ArcGIS 9.1 Network Analyst provided by Environmental Science Research Institute and it has been evaluated by GIS users.
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Boström, Victor. "Lokaliseringsutredning av tankstationer med hjälp av GIS : En fallstudie av Luleå." Thesis, Luleå tekniska universitet, Arkitektur och vatten, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63717.
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Sweden’s national goal to have all vehicles to be zero emission vehicles by year 2030 puts high demands on the infrastructure of alternative fuels. Most cities in developed countries already have a working infrastructure for conventional fuels that has been planned with regard to its unique conditions, such as traffic and population density. These conditions of a city are surely not going to change even if every car was replaced by a zero emission vehicle. Today’s infrastructure for conventional fuels is therefore suitable also for alternative fuels. Electric vehicles on the other hand takes much more time to reload than it takes to refuel a normal car, which makes service stations less suitable locations for charging them. Electric vehicles’ relatively short range (150-600 km) will most probably not affect how a city’s inhabitants move within the city. In this master thesis the existing infrastructure for both conventional and alternative fuels for public consumption is analyzed, with the purpose to improve its accessibility. The thesis is supposed to facilitate the Municipality of Luleå’s planning before establishing new service stations. The method results in a couple of proposed areas that would benefit the fuel accessibility the most, both to its citizens and to commuters of other cities. Keywords: fuel, gas station, Network AnalystSveriges mål om att alla fordon ska vara fossiloberoende år 2030 ställer höga krav på infrastrukturen för alternativa drivmedel. De flesta städer i utvecklade länder har redan en infrastruktur för konventionella drivmedel som är planerad utifrån stadens unika förutsättningar, så som trafik och invånartäthet. Dessa förutsättningar kan man med säkerhet anta kvarstår även om alla dagens bilar byttes ut mot fossiloberoende bilar. Dagens infrastruktur för konventionella drivmedel är därför även lämplig för alternativa drivmedel. Elbilar däremot tar mycket längre tid att ladda än det tar att tanka en vanlig bil, och därför är drivmedelsanläggningar inte den bäst lämpade platsen för laddningsstationer för elbilar. Elbilarnas förhållandevis korta räckvidd (150-600 km) kommer säkerligen inte att påverka hur en stads invånare rör sig genom staden. I det här examensarbetet analyseras den befintliga strukturen för både konventionella och alternativa drivmedel för publik konsumtion, med syftet att förbättra dess tillgänglighet. Arbetet ska underlätta för Luleå kommun i sitt planeringsarbete inför nya etableringar av drivmedelsanläggningar. Metoden leder till förslag på områden som bäst hade ökat tillgängligheten till drivmedel för både stadens invånare och pendlare från andra städer. Sökord: bensinstation, drivmedel, Network Analyst
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Cunningham, Eileen R. "An Evaluation of the Accessibility of the Public Transit Network to Commuting Patterns in the Greater Cincinnati Area." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1250550537.
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Gillman, Malin. "Eco-route modelling using GIS : How to find the most sustainable route option." Thesis, Umeå universitet, Institutionen för geografi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185860.
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In a time when the concept of sustainability is gaining increasing attention among the public, as well as among stake holders and policy makers, informing people about what the most sustainable choice to make is, is crucial in leading people in the right direction. Travelling is an activity requiring a traveller to make multiple choices, with one of the choices being which route between two places to take. The transport sector is also a strong contributing cause to global issues such as climate change, wherefore choices made in relation to transportation are highly relevant in regard to sustainable development. Up until today, most traffic information systems for passenger car users, only provide travellers with suggestions about the fastest, or the shortest, route option. This study aims at proposing a modelling structure using GIS software, that could also return the most sustainable route alternative. The complexity of the many spatial impacts of road transportation is thoroughly discussed in the literature review, together with dilemmas regarding route choice behaviours. A proposed modelling structure is presented, with the structure also empirically being examined as a “proof of concept”. The empirical work takes place in the urban area of Hörnefors, Sweden, and findings confirm the applicability of the proposed workflow. In the specific case of Hörnefors, three distinct route options are investigated, in relation to four sustainability impact variables. The variables investigated are fuel consumption, air pollution, noise, and safety. Results show that the, by far, longest route, is in fact returned as the most sustainable route option. The other two route options exhibit impacts of around double the amount of impacts yielded by the most sustainable one. The generalised sustainability cost is significantly mostly determined by the air pollution variable, due to its far-reaching spatial dispersion patterns yielding impacts even at long distances from a road. The potential application of the inclusion of sustainability in traffic information systems are additionally reviewed, according to the behavioural mechanisms mentioned in the literature 4review. Estimations of in what contexts “most sustainable route” suggestions are potentially most likely to yield behavioural changes, are also made, and assessed. Conclusions suggest that an inclusion of “most sustainable route option” modelling into travel information systems, have the highest potential to affect route choices when the user is driving at locations previously unvisited, due to the inexistence of a status quo route in such contexts.
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Pasha, Imtiyaz. "Ambulance management system using GIS." Thesis, Linköping University, Department of Computer and Information Science, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7058.
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For emergency service providers, giving their service in least time shows their best performance. Emergency hospitals will be at their best if the ambulance reaches the site in Golden hour where life of injured persons can be saved. Ambulance uses the road network to reach the accident site. Today there are many GIS based systems being developed for routing of ambulance using GPS and other real-time technologies. These systems are useful and play a major role in solving the routing problem. But now roads are so congested that it difficult for the Ambulance drivers to travel and reach the accident.
In this thesis present study area is studied and problems faced by emergency service providers on road network are identified. In this thesis GIS/GPS/GSM based prototype system has been developed for routing of ambulance on road network of Hyderabad city (AMS). This prototype is designed such that it finds the accident location on the road network and locates the nearest ambulance to incident site using the real-time technologies (GPS/GSM). AMS creates the fastest route from nearest ambulance to accident site, and from there to nearest hospital. Congestion on roads during peak hours is considered, and the fastest route on both major and minor roads is created.
In this thesis AMS user interface has been developed using VBA, ArcGIS (network analyst). This Ambulance management system has been developed using software engineering model rapid prototyping model and has been evaluated by GIS users
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Buonocore, Chiara. "Development of a model to choose the path of cyclists using GPS data collected via smartphone." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/17199/.
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Nowadays it is impossible being indifferent to the improvement of the urbanization and the mobility and sustainable road infrastructures.It has to be taken into account the bike as a mode of transport for many reasons such as:reduction of pollution and the emissions,safety on the road,less space and healthy.Mostly in big cities,perhaps it is the fastest mode of transport because it's not subject to traffic and its bottlenecks that block the flow.The Netherlands is the most interested country to travel by bike.It's the place where there are more bikes than cars.In recent years the availability of GPS data has seen a marked improvement in terms of accuracy,continuity and quality of data,thanks to the spread of smartphones and applications for auto-location and navigation.The main advantage is to obtain information on the travel routes actually followed by a large sample of cyclists on the entire network, from their origin to their destination.When GPS tracks can be attributed to detailed transport networks, it is possible to evaluate the factors that users consider in the process of choosing a specific route.It's important to study the choice of the route that cyclists make for many reasons.The objective of this thesis is to examine the aspects that the cyclists taking into account when they choose a route instead of another one.We want to focus on the time travelled,considering the average speed per each link and its correspondent length,and the average waiting times at the intersections:how the time influences cyclists choice. This research will investigate which aspects of the bicycle infrastructures have greater or lesser repercussions on the path made by the cyclists and to model their route choices.It will explore the link between the routes chosen by the cyclists and some attributes of the transport network of the Netherlands.The chosen routes will be compare with the fastest and the shortest calculated thanks to the network analyst in ArcMap for each OD pair.
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Post, David L. "Network Management: Assessing Internet Network-Element Fault Status Using Neural Networks." Ohio : Ohio University, 2008. http://www.ohiolink.edu/etd/view.cgi?ohiou1220632155.
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Lim, Kok Seng. "Analysis of network management protocols in optical networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FLim%5FK.pdf.
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Woodbury, Nathan Scott. "Network Reconstruction and Vulnerability Analysis of Financial Networks." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6370.
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Passive network reconstruction is the process of learning a structured (networked) representation of a dynamic system through the use of known information about the structure of the system as well as data collected by observing the inputs into a system along with the resultant outputs. This work demonstrates an improvement on an existing network reconstruction algorithm so that the algorithm is capable of consistently and perfectly reconstructing a network when system inputs and outputs are measured without error. This work then extends the improved network reconstruction algorithm so that it functions even in the presence of noise as well as the situation where inputs into the system are unknown. Furthermore, this work demonstrates the capability of the new extended algorithms by reconstructing financial networks from stock market data, and then performing an analysis to understand the vulnerabilities of the reconstructed network to destabilization through localized attacks. The creation of these improved and extended algorithms has opened many theoretical questions, paving the way for future research into network reconstruction.
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Silva, do Monte Lima Jennifer. "Performance analysis of network composition in ambient networks." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/2637.
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Previous issue date: 2007Conselho Nacional de Desenvolvimento Científico e Tecnológico
Atualmente, o compartilhamento de recursos e oferta de serviços entre redes são permitidos apenas através de intensa configuração manual e acordos prévios entre as redes envolvidas. Devido às diferentes tecnologias de acesso, à heterogeneidade dos dispositivos e dos serviços e a mobilidade dos usuários, o gerenciamento dos recursos se torna uma tarefa ainda mais complexa. As Redes de Ambiente surgem para permitir a cooperação instantânea e dinâmica de redes heterogêneas pertencentes a diferentes domínios administrativos e tecnológicos, através de um novo conceito chamado de Composição de Redes. A Composição permite a disponibilização de serviços e o compartilhamento de recursos entre redes, via Acordo de Composição. O desempenho da composição tem um fator crucial na viabilidade das Redes de Ambiente, devido à alta demanda por composição em uma interação de um usuário típico com a rede. Estas composições de redes mudam todo o cenário e trazem novas complicações para o processo tornando necessária a avaliação da estabilidade e da escalabilidade das mesmas. Diante da impossibilidade de testar tais conceitos de forma prática e real, optouse por fazê-lo através de simulação. Para atingir este objetivo foi especificado e implementado um simulador para Composições de Redes de Ambiente. Este simulador tem como objetivo principal avaliar o desempenho da composição mostrando que a mesma não representa um gargalo para a implantação das Redes de Ambiente
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Oesterheld, Matthias. "Analysis of biomolecular networks using a generic network analysis suite." kostenfrei, 2008. http://mediatum2.ub.tum.de/doc/646475/646475.pdf.
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Vu, Xuan Thang. "Joint Network / Channel Decoding over Noisy Wireless Networks." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01060330.
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Network coding (NC) has gained much research attention as a potential candidate to solve the demand for higher spectral e ciency of modern wireless communications. Many research papers have investigated the performance of NC-aided networks such as throughput and outage capacity. However, the analysis of NC in practical systems where NC is combined with other techniques such as channel coding is still immature to fully understand its potential performance. In this thesis, we aim to design high performance receivers and analyze its performance for network-coded cooperative networks in practical scenarios. Firstly, we propose two Iterative Network/Channel Decoding (INCD) algorithms for the Multiple-Access Relay Channel (MARC) with two notable relaying schemes named Decode-and-Forward (DF) and Demodulate-and-Forward (DMF). The INCD algorithm operates based on turbo-like decoding methods and reduces the impact of the error propagation problem with the aid of a channel-aware receiver design. Both perfect Channel State Information (CSI) and imperfect CSI at the receiver side are investigated. We propose a practical method that forwards the quantized version of the relay decoding errors to the destination. It is shown that the proposed algorithms achieve full diversity gain and signi cantle outperforms solutions which do not take care of error propagation. We also show that the number of pilot symbols a ects only the coding gain but has a negligible impact on the diversity order, while the quantization level a cts both the diversity and coding gain. Secondly, we propose a Near Optimal Joint Network/Channel Decoding (NOJNCD) algorithm for the MARC that allows to analyze the system Bit Error Rate (BER). The NOJNCD algorithm performs network decoding and channel decoding in one decoding step of the super code, which comprises of all trellis states of individual code at the sources via NC. Furthermore, NC combined with Relay Selection (RS) is considered and the achievable diversity order is studied with the aid of outage analysis. We analytically show that Single Relay Selection (SRS) always achieves a diversity order two and Multiple Relay Selection (MRS) can achieve full diversity gain only when the number of selected relays exceeds the number of the sources. Last but not least, we propose a so-called partial relaying protocol to improve the spectral e ciency for channel coding assisted relay networks. Closed-form expression of the BER and the system diversity order are computed for partial relaying. We show, by analysis and simulations, that with a proper Convolutional Code (CC), partial relaying can achieve full diversity gain and same coding gain as the classical (full) relaying protocol in nite signal-to-noise ratio region while it obtains a better spectrum usage. Moreover, we propose a new protocol based on partial relaying in opportunistic relaying cooperative networks and show that this protocol signi cantly outperforms the NC-based cooperation in some circumstances.
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Zhou, Lin. "Active network management and uncertainty analysis in distribution networks." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675697.
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In distribution networks, the traditional way to eliminate network stresses caused by increasing generation and demand is to reinforce the primary network assets. A cheaper alternative is active network management (ANM) which refers to real-time network control to resolve power flow, voltage, fault current and security issues. However, there are two limitations in ANM. First, previous ANM strategies investigated generation side and demand side management separately. The generation side management evaluates the value from ANM in terms of economic generation curtailment. It does not consider the potential benefits from integrating demand side response such as economically shifting flexible load over time. Second, enhancing generation side management with load shifting requires the prediction of network stress whose accuracy will decrease as the lead time increases. The uncertain prediction implies the potential failure of reaching expected operational benefits. However, there is very limited investigation into the trade-offs between operational benefit and its potential risk. In order to tackle the challenges, there are two aspects of research work in this thesis. 1) Enhanced ANM. It proposes the use of electric vehicles (EVs) as responsive demand to complement generation curtailment strategies in relieving network stress. This is achieved by shifting flexible EV charging demand over time to absorb excessive wind generation when they cannot be exported to the supply network. 2) Uncertainty management. It adopts Sharpe Ratio and Risk Adjust Return On Capital concepts from financial risk management to help the enhanced ANM make operational decisions when both operational benefit and its associated risk are considered. Copula theory is applied to further integrate correlations of forecasting errors between nodal power injections (caused by wind and load forecasting) into uncertainty management. The enhanced ANM can further improve network efficiency of the existing distribution networks to accommodate increasing renewable generation. The cost-benefit assessment informs distribution network operators of the trade-off between investment in ANM strategy and in the primary network assets, thus helping them to make cost-effective investment decisions. The uncertainty management allows the impact of risks that arise from network stress prediction on the expected operational benefits to be properly assessed, thus extending the traditional deterministic cost-benefit assessment to cost-benefit-risk assessment. Moreover, it is scalable to other systems in any size with low computational burden, which is the major contribution of this thesis.
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She, Huimin. "Network-Calculus-based Performance Analysis for Wireless Sensor Networks." Licentiate thesis, KTH, Electronic, Computer and Software Systems, ECS, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10686.
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Recently, wireless sensor network (WSN) has become a promising technologywith a wide range of applications such as supply chain monitoringand environment surveillance. It is typically composed of multiple tiny devicesequipped with limited sensing, computing and wireless communicationcapabilities. Design of such networks presents several technique challengeswhile dealing with various requirements and diverse constraints. Performanceanalysis techniques are required to provide insight on design parametersand system behaviors.
Based on network calculus, we present a deterministic analysis methodfor evaluating the worst-case delay and buffer cost of sensor networks. Tothis end, three general traffic flow operators are proposed and their delayand buffer bounds are derived. These operators can be used in combinationto model any complex traffic flowing scenarios. Furthermore, the methodintegrates a variable duty cycle to allow the sensor nodes to operate at lowrates thus saving power. In an attempt to balance traffic load and improveresource utilization and performance, traffic splitting mechanisms areintroduced for mesh sensor networks. Based on network calculus, the delayand buffer bounds are derived in non-splitting and splitting scenarios.In addition, analysis of traffic splitting mechanisms are extended to sensornetworks with general topologies. To provide reliable data delivery in sensornetworks, retransmission has been adopted as one of the most popularschemes. We propose an analytical method to evaluate the maximum datatransmission delay and energy consumption of two types of retransmissionschemes: hop-by-hop retransmission and end-to-end retransmission.
We perform a case study of using sensor networks for a fresh food trackingsystem. Several experiments are carried out in the Omnet++ simulationenvironment. In order to validate the tightness of the two bounds obtainedby the analysis method, the simulation results and analytical results arecompared in the chain and mesh scenarios with various input traffic loads.From the results, we show that the analytic bounds are correct and tight.Therefore, network calculus is useful and accurate for performance analysisof wireless sensor network.
Ipack VINN Excellence Center
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Leung, Ian Xiao Yin. "Fast network analysis and applications in real-world networks." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609931.
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Junuthula, Ruthwik Reddy. "Modeling, Evaluation and Analysis of Dynamic Networks for Social Network Analysis." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1544819215833249.
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Hagman, Robin, and Anna Hillberg. "Analys av brandstationslokalisering - En fallstudie om Jönköpings nya brandstation." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158173.
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I och med urbaniseringen i det svenska samhället har många städer vuxit och utvecklats till storstäder. Storstäder har många utmaningar, allt ifrån att det ska finnas jobb och bostadsmöjligheter så måste även infrastrukturen i form av transportmöjligheter utvecklas i takt med befolkningsökningen. Större befolkning betyder mer människor i rörelse som lätt leder till försämrad framkomlighet i trafiken. Detta examensarbete har utförts åt Räddningstjänsten i Jönköpings kommun med syftet att bidra med ett underlag angående vad en ny brandstation skulle generera i minskade insatstider och samhällsnytta. Räddningstjänsten upplever att trafiken i Jönköpings tätort bidrar till sämre framkomlighet som i sin tur leder till att räddningstjänsten får längre insatstider än önskat. Därför planerar kommunen att en ny brandstation ska byggas. I examensarbetet har samhällsnyttan för den nya stationen undersökts genom att bygga en GIS-modell där det går att simulera och undersöka insatstiden för räddningstjänsten baserat på historiska händelser. En litteraturstudie utfördes för att ge en grundläggande kunskapsmässig förståelse för området examensarbetet behandlar. För att få förståelse och kunskap om nuläget för Räddningstjänsten i Jönköping utfördes tre olika intervjuer. Intervjuerna riktade sig till personer som är involverade i utvecklingsprocessen av Jönköpings infrastruktur. Den största delen av examensarbetet var skapandet av GIS-modellen och analysen av det resultat modellen genererade. Under hela examensarbetet har en dialog med Räddningstjänsten i Jönköping förts. Detta för att få hjälp med tolkning av den historiska data räddningstjänsten bidragit med men också för att kontrollera att GIS-modellen resulterade i svar som verkade sannolika och användbara. Examensarbetet resulterade i att en ny brandstation skulle minska medelinsatstiden för räddningstjänsten och generera samhällsnytta. Eftersom en modell aldrig kan ge samma resultat som verkligheten är det viktigt att ta andra saker än enbart GIS-modellens resultat i beaktning när det diskuteras vad samhällsnyttan och en minskning av medelinsatstiden egentligen har för betydelse. Examensarbetet anses kunna vara en del av det beslutsunderlag som används vid beslutsfattandet om en ny brandstation i Jönköpings kommun.
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Morley, George David. "Analysis and design of ring-based transport networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60329.pdf.
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Diana, Gary M. "Internetworking : an analysis and proposal /." Online version of thesis, 1990. http://hdl.handle.net/1850/10605.
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Kouhbor, Shahnaz University of Ballarat. "Optimal number and placement of network infrastructure in wireless networks." University of Ballarat, 2007. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/12762.
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Wireless Local Area Networks (WLANs) have become a major success in telecommunications during the last few years, due to advantages such as mobility, flexibility, and easier maintenance. A device called an access point (AP) acts as a base station in WLAN for connecting a group of users to the network via radio signal. During the planning of such a network an important problem is to determine the optimal number of these devices and their placement/distribution so that coverage, capacity, and physical security are maximised at minimum cost. In this thesis we are using continuous optimisation techniques to optimise the number of APs and their distribution while cost of deployment is reduced and physical security of the network is enhanced. To find the number and placement of APs, we developed a multi-objective functions model based on path losses and power for free space environments. The two functions in the models are combined by using a balancing parameter. Since it is recognised that some of the objectives can be handled one at a time, in another approach, we followed a step-by-step procedure. We start with a novel optimisation model based on path losses for indoor environments including obstacles. Cost of deployment is saved by finding the minimum number of APs ensuring that the path loss at each test point/receiver is below the given maximum path loss. Next, the physical security of the network is enhanced by placing the APs far from places accessible to unauthorised users to reduce the risk of intrusion into the network. This is achieved in the framework of the model by introducing potential unauthorised users in unauthorised areas for whom coverage is minimised. Due to the presence of obstacles in indoor buildings, the path loss function is discontinuous. Therefore, the objective functions are very complicated and most of the existing optimisation algorithms cannot be applied to solve the problem. We use a global optimisation algorithm that is not used by other researchers to solve the same problem. To validate the accuracy of the optimisation model and performance of the numerical methods, we run tests on several indoor buildings and use wide range of WLAN parameters. The results demonstrate the quality of our model and algorithm. Based on the proposed model and algorithm, we developed a software to assist the network designers in planning wireless LANs.Doctor of Philosophy
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Kouhbor, Shahnaz. "Optimal number and placement of network infrastructure in wireless networks." University of Ballarat, 2007. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/14597.
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Wireless Local Area Networks (WLANs) have become a major success in telecommunications during the last few years, due to advantages such as mobility, flexibility, and easier maintenance. A device called an access point (AP) acts as a base station in WLAN for connecting a group of users to the network via radio signal. During the planning of such a network an important problem is to determine the optimal number of these devices and their placement/distribution so that coverage, capacity, and physical security are maximised at minimum cost. In this thesis we are using continuous optimisation techniques to optimise the number of APs and their distribution while cost of deployment is reduced and physical security of the network is enhanced. To find the number and placement of APs, we developed a multi-objective functions model based on path losses and power for free space environments. The two functions in the models are combined by using a balancing parameter. Since it is recognised that some of the objectives can be handled one at a time, in another approach, we followed a step-by-step procedure. We start with a novel optimisation model based on path losses for indoor environments including obstacles. Cost of deployment is saved by finding the minimum number of APs ensuring that the path loss at each test point/receiver is below the given maximum path loss. Next, the physical security of the network is enhanced by placing the APs far from places accessible to unauthorised users to reduce the risk of intrusion into the network. This is achieved in the framework of the model by introducing potential unauthorised users in unauthorised areas for whom coverage is minimised. Due to the presence of obstacles in indoor buildings, the path loss function is discontinuous. Therefore, the objective functions are very complicated and most of the existing optimisation algorithms cannot be applied to solve the problem. We use a global optimisation algorithm that is not used by other researchers to solve the same problem. To validate the accuracy of the optimisation model and performance of the numerical methods, we run tests on several indoor buildings and use wide range of WLAN parameters. The results demonstrate the quality of our model and algorithm. Based on the proposed model and algorithm, we developed a software to assist the network designers in planning wireless LANs.Doctor of Philosophy
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Xie, Jing. "A Temporal Network Calculus for Performance Analysis of Computer Networks." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14619.
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One inevitable trend of network development is to deliver information with various traffic characteristics and diverse Quality of Service (QoS) requirements. In response to the continually growing demand for more bandwidth, network performance analysis is needed to optimize the performance of existing technologies and evaluate the efficiency of new ones. Performance analysis investigates how traffic management mechanisms deployed in the network affect the resource allocation among users and the performance which the users experience. This topic can be investigated by constructing models of traffic management mechanisms and studying how these mechanisms perform under various types of network traffic. To this end, appropriate mathematical models are needed to characterize the traffic management mechanisms which we are interested in and represent different types of network traffic. In addition, fundamental properties which can be employed to manipulate the models should be explored. Over the last two decades a relatively new theory, stochastic network calculus, has been developed to enable mathematical performance analysis of computer networks. Particularly, several related processes are mathematically modeled, including the arrival process, the waiting process and the service process. This theory can be applied to the derivation and calculation of several performance metrics such as the backlog bound and the delay bound. The most attractive contribution of stochastic network calculus is to characterize the behavior of a process based on some bound on the complementary cumulative distribution function (CCDF). The behavior of a computer network is often subject to many irregularities and stochastic fluctuations. The models based on the bound on the CCDF are not very accurate, while they are more feasible for abstracting computer network systems and representing various types of network traffic. This thesis is devoted to investigate the performance of networks from the temporal perspective. Specifically, the traffic arrival process characterizes the distribution of the cumulative inter-arrival time and the service process describes the distribution of the cumulative service time. Central to finding a bound on the CCDF of the cumulative interarrival time and the cumulative service time, several variations of the traffic characterization and the service characterization are developed. The purpose of developing several variations to characterize the same process is to facilitate the derivation and calculation of performance metrics. In order to derive and calculate the performance metrics, four fundamental properties are explored, including the service guarantees, the output characterization, the concatenation property and the superposition property. The four properties can be combined differently when deriving the performance metrics of a single node, a series of nodes or the superposition flow. Compared to the available literature on stochastic network calculus which mainly focuses on studying network performance in the spacedomain, this work develops a generic framework for mathematically analyzing network performance in the time-domain. The potential applications of this temporal approach include the wireless networks and the multi-access networks. Furthermore, the complete procedure of concretizing the generic traffic models and service models is presented in detail. It reveals the key of applying the developed temporal network calculus approach to network performance analysis, i.e., to derive the bounding function which is the upper bound on the tail probability of a stochastic process. Several mathematical methods are introduced, such as the martingale, the moment generating function (MGF) and a concentration theory result
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Hui, Daniel Hang-Yan. "Protocol validation via reachability analysis : an implementation." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24689.
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Reachability analysis is one of the earliest and most common techniques for protocol validation. It is well suited to checking the protocol syntactic properties since they are a direct consequence of the structure of the reachability tree. However, validations of unbounded protocols via reachability analysis always lead to the "state explosion" problem. To overcome this, a new approach in reachability analysis has been proposed by Vuong et al [Vuong 82a, 83a]. While not loosing any information on protocol syntactic properties, the Teachability tree constructed by the new approach for all non-FIFO and for a particular set of FIFO protocols (called well-ordered protocols) will become finite. This thesis is concerned with the implementation of an integrated package called VALIRA (VALIdation via Reachability Analysis) which bases on both the proposed technique and the conventional technique. Details and implementation of the various approaches used in VALIRA are presented in order to provide an insight to the package. Various features of the package are demonstrated with examples on different types of protocols, such as the FIFO, the non-FIFO, and the priority protocols. The use of VALIRA was found to be practical in general, despite some limitations of the package. Further enhancements on the VALIRA are also suggested.Science, Faculty of
Computer Science, Department of
Graduate
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Baronikian, Haig. "Modelling and analysis of a computer conferencing system." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63756.
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Carter, Steven Michael. "Implementation and analysis of the IP measurement protocol (IPMP)." Master's thesis, Mississippi State : Mississippi State University, 2001. http://library.msstate.edu/etd/show.asp?etd=etd-11152001-090121.
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Hall, Kristopher Joseph. "Thwarting Network Stealth Worms in Computer Networks through Biological Epidemiology." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27726.
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This research developed a system, Rx, to provide early identification and effective control of network stealth worms in digital networks through techniques based on biological epidemiology. Network stealth worms comprise a class of surreptitious, self-propagating code that spread over network connections by exploiting security vulnerabilities in hosts. Past outbreaks due to traditional worms subverted hundreds of thousands of machines. Network stealth worms exacerbate that threat by using clandestine methods to maintain a persistent presence in the network.
Biological epidemiology was shown to support the real-time detection, characterization, forecasting, and containment of network stealth worms. Epidemiology describes a scientific methodology in biology that seeks to understand, explain, and control disease. Bio-mathematical modeling led to the development of a mechanism for digital networks to identify worm infection behavior buried in anomaly data, to characterize a worm, and to forecast the temporal spread of a worm. Demographic analysis of the infected hosts revealed the subset of vulnerable machines within the population. The automated response of advanced quarantine used this information to control the spread of an identified worm by isolating both infected and vulnerable machines.
The novel contributions of this research included the identification of a network stealth worm at the network-level based on end-host reports while simultaneously characterizing and forecasting the spread of the worm. Additionally, this task offered the technique of advanced quarantine through demographic analysis of the population. This work resulted in a scalable, fault-tolerant strategy that dramatically enhanced the survival rate of network hosts under attack by a stealth worm. Moreover, this approach did not require new hardware, changes to existing protocols, or participation outside the implementing organization.
This research showed application to a wider range of challenges. The bio-mathematical models are extensible, allowing Rx to respond to variations on the self-propagating code presented here. The approach is applicable to other forms of malware beyond self-propagating code by interchanging the epidemic model with one more appropriate. Lastly, the strategy allowed anomaly detectors to be sensitive to lower reporting thresholds and a variety of often benign yet potentially useful events.Ph. D.
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Moore, John David. "Making Sense of Networks: Exploring How Network Participants Understand and Use Information From Social Network Analysis." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/103640.
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Many of today's complex public issues are best addressed by multi-sectoral multi-organizational responses that include different types of organizations working together (Kettl, 2008; O'Toole, 1997). Social network analysis (SNA) of interorganizational networks has emerged as a useful tool for network managers to understand the structure and function of the complex networks in which they seek to manage (Human and Provan, 1997, 2000; Provan and Milward, 1995; Provan, Sebastian, and Milward, 1996; Provan, Veazie, Staten, and Teufel-Shone, 2005).
The output of an interorganizational SNA typically provides a range of information to network managers including network plots. The network plots provide visual representations of different aspects of the network by showing the kinds of ties between the actors in the network.
The information from network analyses can help network managers encourage systems thinking, see the different roles played by organizations, or identify links to outside resources among many other uses, but "will only have practical value to communities if it can be effectively presented, discussed, accepted, and acted on by community leaders and network participants [emphasis added]." (Provan et al., 2005, p. 610). However, little is currently known about if or how the information embedded in network plots is accepted or acted on by network participants.
The visual representations of the network (network plots) provided to network participants following a SNA are often open to a range of interpretations that may or may not align with the findings of the analyst or the intended use by network managers, raising many interesting questions. Little is currently known about how differently situated network participants might interpret the same network plots differently. Nor do we understand what factors might influence different individuals or organizations to come up with different interpretations.
After conducting a SNA and presenting it to network participants, I conducted interviews with a range of different representatives from participating organizations. I used a particular form of semi-structured interview, a situated micro-element interview from Dervin's Sense Making Methodology (SMM) (Dervin, Foreman-Wernet, and Lauterbach, 2003). I then analyzed the interview transcripts using standard qualitative coding methods (Bailey, 2007) to see if themes emerged that addressed the research questions.
I found that most informants had trouble extracting information and meaning from their examination of the plots without that meaning and interpretation being provided by the expert analyst. I posit some potential explanations for why that might be so in the case I studied. I then turn to some interesting methodological considerations that emerged from taking the perspectives of network participants seriously.
Finally, I synthesize the subject area and methodological findings into a refined framework for sense-making around network plots and offer propositions and potential approaches for future research.Doctor of Philosophy
Many of today's complex public issues are best addressed by multi-sectoral multi-organizational responses that include different types of organizations working together (Kettl, 2008; O'Toole, 1997). Social network analysis (SNA) of interorganizational networks has emerged as a useful tool for network managers to understand the structure and function of the complex networks in which they seek to manage (Human and Provan, 1997, 2000; Provan and Milward, 1995; Provan, Sebastian, and Milward, 1996; Provan, Veazie, Staten, and Teufel-Shone, 2005). The output of an interorganizational SNA typically provides a range of information to network managers including network plots. The network plots provide visual representations of different aspects of the network by showing the kinds of ties between the actors in the network. The information from network analyses can help network managers encourage systems thinking, see the different roles played by organizations, or identify links to outside resources among many other uses, but "will only have practical value to communities if it can be effectively presented, discussed, accepted, and acted on by community leaders and network participants [emphasis added]." (Provan et al., 2005, p. 610). However, little is currently known about if or how the information embedded in network plots is accepted or acted on by network participants. The visual representations of the network (network plots) provided to network participants following a SNA are often open to a range of interpretations that may or may not align with the findings of the analyst or the intended use by network managers, raising many interesting questions. Little is currently known about how differently situated network participants might interpret the same network plots differently. Nor do we understand what factors might influence different individuals or organizations to come up with different interpretations. After conducting a SNA and presenting it to network participants, I conducted interviews with a range of different representatives from participating organizations. I used a particular form of semi-structured interview, a situated micro-element interview from Dervin's Sense Making Methodology (SMM) (Dervin, Foreman-Wernet, and Lauterbach, 2003). I then analyzed the interview transcripts using standard qualitative coding methods (Bailey, 2007) to see if themes emerged that addressed the research questions. I found that most informants had trouble extracting information and meaning from their examination of the plots without that meaning and interpretation being provided by the expert analyst. I posit some potential explanations for why that might be so in the case I studied. I then turn to some interesting methodological considerations that emerged from taking the perspectives of network participants seriously. Finally, I synthesize the subject area and methodological findings into a refined framework for sense-making around network plots and offer propositions and potential approaches for future research.
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Moore, John. "Making Sense of Networks: Exploring How Network Participants Understand and Use Information From Social Network Analysis." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103640.
Full textAbstract:
Many of today's complex public issues are best addressed by multi-sectoral multi-organizational responses that include different types of organizations working together (Kettl, 2008; O'Toole, 1997). Social network analysis (SNA) of interorganizational networks has emerged as a useful tool for network managers to understand the structure and function of the complex networks in which they seek to manage (Human and Provan, 1997, 2000; Provan and Milward, 1995; Provan, Sebastian, and Milward, 1996; Provan, Veazie, Staten, and Teufel-Shone, 2005).
The output of an interorganizational SNA typically provides a range of information to network managers including network plots. The network plots provide visual representations of different aspects of the network by showing the kinds of ties between the actors in the network.
The information from network analyses can help network managers encourage systems thinking, see the different roles played by organizations, or identify links to outside resources among many other uses, but "will only have practical value to communities if it can be effectively presented, discussed, accepted, and acted on by community leaders and network participants [emphasis added]." (Provan et al., 2005, p. 610). However, little is currently known about if or how the information embedded in network plots is accepted or acted on by network participants.
The visual representations of the network (network plots) provided to network participants following a SNA are often open to a range of interpretations that may or may not align with the findings of the analyst or the intended use by network managers, raising many interesting questions. Little is currently known about how differently situated network participants might interpret the same network plots differently. Nor do we understand what factors might influence different individuals or organizations to come up with different interpretations.
After conducting a SNA and presenting it to network participants, I conducted interviews with a range of different representatives from participating organizations. I used a particular form of semi-structured interview, a situated micro-element interview from Dervin's Sense Making Methodology (SMM) (Dervin, Foreman-Wernet, and Lauterbach, 2003). I then analyzed the interview transcripts using standard qualitative coding methods (Bailey, 2007) to see if themes emerged that addressed the research questions.
I found that most informants had trouble extracting information and meaning from their examination of the plots without that meaning and interpretation being provided by the expert analyst. I posit some potential explanations for why that might be so in the case I studied. I then turn to some interesting methodological considerations that emerged from taking the perspectives of network participants seriously.
Finally, I synthesize the subject area and methodological findings into a refined framework for sense-making around network plots and offer propositions and potential approaches for future research.Doctor of Philosophy
Many of today's complex public issues are best addressed by multi-sectoral multi-organizational responses that include different types of organizations working together (Kettl, 2008; O'Toole, 1997). Social network analysis (SNA) of interorganizational networks has emerged as a useful tool for network managers to understand the structure and function of the complex networks in which they seek to manage (Human and Provan, 1997, 2000; Provan and Milward, 1995; Provan, Sebastian, and Milward, 1996; Provan, Veazie, Staten, and Teufel-Shone, 2005). The output of an interorganizational SNA typically provides a range of information to network managers including network plots. The network plots provide visual representations of different aspects of the network by showing the kinds of ties between the actors in the network. The information from network analyses can help network managers encourage systems thinking, see the different roles played by organizations, or identify links to outside resources among many other uses, but "will only have practical value to communities if it can be effectively presented, discussed, accepted, and acted on by community leaders and network participants [emphasis added]." (Provan et al., 2005, p. 610). However, little is currently known about if or how the information embedded in network plots is accepted or acted on by network participants. The visual representations of the network (network plots) provided to network participants following a SNA are often open to a range of interpretations that may or may not align with the findings of the analyst or the intended use by network managers, raising many interesting questions. Little is currently known about how differently situated network participants might interpret the same network plots differently. Nor do we understand what factors might influence different individuals or organizations to come up with different interpretations. After conducting a SNA and presenting it to network participants, I conducted interviews with a range of different representatives from participating organizations. I used a particular form of semi-structured interview, a situated micro-element interview from Dervin's Sense Making Methodology (SMM) (Dervin, Foreman-Wernet, and Lauterbach, 2003). I then analyzed the interview transcripts using standard qualitative coding methods (Bailey, 2007) to see if themes emerged that addressed the research questions. I found that most informants had trouble extracting information and meaning from their examination of the plots without that meaning and interpretation being provided by the expert analyst. I posit some potential explanations for why that might be so in the case I studied. I then turn to some interesting methodological considerations that emerged from taking the perspectives of network participants seriously. Finally, I synthesize the subject area and methodological findings into a refined framework for sense-making around network plots and offer propositions and potential approaches for future research.
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Gabdurahmanov, Murat, and Simon Trygg. "Analysis and Evaluation of Network Management Solutions : A Comparison of Network Management Solutions Suitable for Networks with 2,500+ Devices." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188793.
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Some companies today are using sub-optimal and nearly obsolete management systems for their networks. Given the large number of different services that are demanded by users, there is a need to adapt the network structure to support the current and potential future demands. As a result, there is a need for new Network Management Solutions (NMSs). The aim of this thesis project is to help a company who uses a NMS called Local Area Network (LAN) Management Solution (LMS). LMS was designed by Cisco for managing LAN networks. However, the company’s demands are growing and they need to expand their network more than expected. Moreover, LMS is designed to only support devices by Cisco, whereas the company wants a universal solution with wide device support from many manufacturers. This thesis presents an analysis of their current system and suggests potential solutions for an upgrade that will meet all of the company’s demands and will have a long operating life. To help find reasonable solutions a thorough evaluation of their existing NMS and network monitoring and management needs was made. This evaluation gave good insights into different aspects of their system. A reasonable solution was found by following a three-step approach, beginning with 82 possible solutions, filtering out and breaking down with each step, until only the most suitable NMS was left. Two NMSs has been proposed as equally suitable replacements: IBM Tivoli Netcool/OMNIbus and ManageEngine OpManager. Regardless of which one is chosen, they both have the following advantages over the company’s existing NMS: they are very stable solutions which can handle a large number of managed devices; they are universal solutions with wide device support, and the company can add custom support if needed; they are user-friendly with the ability to add custom interfaces; and they both have a professional first-line technical support department locally located.Vissa företag använder idag suboptimala och föråldrade övervakningsssystem för sina nätverk. Med tanke på det stora antalet olika tjänster som efterfrågas av användare finns det ett stort behov av att anpassa nätverksstrukturen för att stödja de nuvarande och potentiellt framtida kraven. Som ett resultat finns det ett behov av nya övervakningssystem (Network Management Solutions (NMSs)) för nätverken. Syftet med detta examensarbete är att hjälpa ett företag som använder NMS:en Local Area Network (LAN) Management Solution (LMS). LMS utecklades av Cisco för att hantera lokala nätverk (LANs). Men med tiden har företagets krav förändrats och de har därför behövt expandera sitt nätverk mer än väntat. Dessutom är LMS endast utformad för att hantera enheter tillverkade av Cisco, medan företaget vill ha en universal lösning med stöd för enheter från många olika tillverkare. Denna rapport presenterar en analys av deras nuvarande system, samt föreslår möjliga lösningar som kan ersätta detta. Den nya lösningen ska vara långvarig samt ska uppfylla alla krav företaget ställt. För att hitta lämpliga lösningar har en grundlig utvärdering av den befintliga NMS:en samt en analys av de ställda kraven utförts. Denna analys gav goda insikter i olika aspekter av deras nuvarande system. En lämplig lösning hittades genom att följa en trestegsmetod. Metoden utgick från 82 möjliga lösningar, som efter flera steg av filtrering resulterade i de mest lämpade ersättningssystemen. Två NMS:er har föreslagits som lika lämpliga ersättare: IBM Tivoli Netcool/OMNIbus och ManageEngine OpManager. Oavsett vilken som väljs, har de båda följande fördelar jämfört med den nuvarande NMS:en: de är båda väldigt stabila lösningar som klarar av en stor mängd hanterade enheter; de är universella lösningar med stöd för en stor mängd olika enheter, dessutom går det även att lägga till eget stöd för enheter vid behov; de är användarvänliga och har möjlighet till att anpassa egna gränssnitt; samt att de båda har en professionell first-line teknisk support placerad lokalt i landet.<p>
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Kozat, Ulaș C. "Heterogeneous wireless networks : an analysis of network and service level diversity /." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1404.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Dunn, Nathan A. "A Novel Neural Network Analysis Method Applied to Biological Neural Networks." Thesis, view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1251892251&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Oregon, 2006.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 122- 131). Also available for download via the World Wide Web; free to University of Oregon users.
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Yang, Zhenyu. "Network Coding in Multihop Wireless Networks: Throughput Analysis and Protocol Design." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-dissertations/222.
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Multi-hop wireless networks have been widely considered as promising approaches to provide more convenient Internet access for their easy deployment, extended coverage, and low deployment cost. However, providing high-speed and reliable services in these networks is challenging due to the unreliable wireless links, broadcast nature of wireless transmissions, and frequent topology changes. On the other hand, network coding (NC) is a technique that could significantly improve the network throughput and the transmission reliability by allowing intermediate nodes to combine received packets. More recently proposed symbol level network coding (SLNC), which combines packets at smaller symbol scale, is a more powerful technique to mitigate the impact of lossy links and packet collisions in wireless networks. NC, especially SLNC, is thus a particular effective approach to providing higher data rate and better transmission reliability for applications such as mobile content distribution in multihop wireless networks. This dissertation focuses on exploiting NC in multihop wireless networks. We studied the unique features of NC and designed a suite of distributed and localized algorithms and protocols for content distribution networks using NC and SLNC. We also carried out a theoretical study on the network capacity and performance bounds achievable by SLNC in mobile wireless networks. We proposed CodeOn and CodePlay for popular content distribution and live multimedia streaming (LMS) in vehicular ad hoc networks (VANETs), respectively, where many important practical factors are taken into consideration, including vehicle distribution, mobility pattern, channel fading and packet collision. Specifically, CodeOn is a novel push based popular content distribution scheme based on SLNC, where contents are actively broadcast to vehicles from road side access points and further distributed among vehicles using a cooperative VANET. In order to fully enjoy the benefits of SLNC, we proposed a suite of techniques to maximize the downloading rate, including a prioritized and localized relay selection mechanism where the selection criteria is based on the usefulness of contents possessed by vehicles, and a lightweight medium access protocol that naturally exploits the abundant concurrent transmission opportunities. CodePlay is designed for LMS applicaitions in VANETs, which could fully take advantage of SLNC through a coordinated local push mechanism. Streaming contents are actively disseminated from dedicated sources to interested vehicles via local coordination of distributively selected relays, each of which will ensure smooth playback for vehicles nearby. CodeOn pursues a single objective of maximizing downloading rate, while CodePlay improves the performance of LMS service in terms of streaming rate, service delivery delay, and bandwidth efficiency simultaneously. CodeOn and CodePlay are among the first works that exploit the features of SLNC to simplify the protocol design whilst achieving better performance. We also developed an analytical framework to compute the expected achievable throughput of mobile content distribution in VANETs using SLNC. We presented a general analytical model for the expected achievable throughput of SLNC in a static wireless network based on flow network theory and queuing theory. Then we further developed the model to derive the expected achievable accumulated throughput of a vehicle driving through the area of interest under a mobility pattern. Our proposed framework captures the effects of multiple practical factors, including vehicle distribution and mobility pattern, channel fading and packet collision, and we characterized the impacts of those factors on the expected achievable throughput. The results from this research are not only of interest from theoretical perspective but also provide insights and guidelines on protocol design in SLNC-based networks.
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Banerji, Pratip K. "An analysis of network management traffic and requirements in wireless networks." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42744.
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Castillejo, Sierra Miguel. "Redes temáticas en la web: estudio de caso de la red temática de la transparencia en Chile." Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/378362.
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El objeto de estudio de esta investigación son las Redes Temáticas, concretamente las Redes Temáticas en la Web y su potencial para extraer datos objetivos de las corrientes de opinión que se generan en torno a un tema de discusión o controversia social.
Esta investigación se estructura a través de cuatro objetivos: caracterizar los componentes de las redes temáticas; caracterizar y evaluar las herramientas para el análisis de redes temáticas en la web; diseñar un Sistema de Análisis de Redes Temáticas en la Web; y aplicar el Sistema de Análisis al caso de estudio de la Red Temática de la Transparencia en Chile.
Como conclusiones, presentamos y caracterizamos los componentes de una red temática en la web: redes de hiperenlaces, actores y temas; analizamos los resultados de la evaluación de las herramientas que consideramos más adecuadas para el de análisis de redes temáticas en la web: IssueCrawler, SocSciBot, Webometric Analyst y VOSON; construimos un sistema de análisis dividido en tres fases: análisis de redes de hiperenlaces, análisis de actores y análisis de temas; y finalmente discutimos los resultados del análisis de la Red Temática de la Transparencia en Chile y los posibles desarrollos futuros de la investigación.The object of study of this research are Issue Networks, namely the Issue networks that are active within the domain of the Internet and their potential to extract objective data from the opinion flows that are generated in regard to an issue of discussion or social controversy. This research is founded on four objectives: the characterization of the components of issue networks; the identification, description and evaluation of existing tools for the analysis of issue networks on the Internet; creation of an Analysis System of Issue Networks on the Internet; and, lastly, the application of the Analysis System to the case study of the Issue Network for Transparency in Chile. In conclusion, we introduce the characteristics of the components of an Issue Network on the Internet: hyperlinks, actors and issue networks; we present the results of the evaluation of the tools that we consider most suitable for the analysis of Issue Networks on the Internet: IssueCrawler, SocSciBot, Webometric Analyst and VOSON; we build an analysis system divided into three parts: network analysis of hyperlinks, stakeholder analysis and issue analysis; and finally we discuss the results of the analysis of the Issue Network for Transparency in Chile and the possible future developments of the investigation.
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Broccatelli, Chiara. "Going beyond secrecy : methodological advances for two-mode temporal criminal networks with Social Network Analysis." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/going-beyond-secrecy-methodological-advances-for-twomode-temporal-criminal-networks-with-social-network-analysis(f0f91f79-7bc3-442c-a16b-e9cf44cc68c3).html.
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This thesis seeks to extend the application of Social Network Analysis (SNA) to temporal graphs, in particular providing new insights for the understanding of covert networks. The analyses undertaken reveal informative features and properties of individuals' affiliations under covertness that also illustrate how both individuals and events influence the network structure. The review of the literature on covert networks provided in the initial two chapters suggests the presence of some ambiguities concerning how authors define structural properties and dynamics of covert networks. Authors sometimes disagree and use their findings to explain opposite views about covert networks. The controversy in the field is used as a starting point in order to justify the methodological application of SNA to understand how individuals involved in criminal and illegal activities interact with each other. I attempt to use a deductive approach, without preconceived notions about covert network characteristics. In particular, I avoid considering covert networks as organisations in themselves or as cohesive groups. I focus on individuals and their linkages constructed from their common participation in illicit events such as secret meetings, bombing attacks and criminal operations. In order to tackle these processes I developed innovative methods for investigating criminals' behaviours over time and their willingness to exchange tacit information. The strategy implies the formulation of a network model in order to represent and incorporate in a graph three types of information: individuals, events, and the temporal dimension of events. The inclusion of the temporal dimension offers the possibility of adopting a more comprehensive theoretical framework for considering individuals and event affiliations. This thesis expands the analysis of bipartite covert networks by adopting several avenues to explore in this perspective. Chapter 3 proposes a different way to represent two-mode networks starting from the use of line-graphs, namely the bi-dynamic line-graph data representation (BDLG), through which it is possible to represent the temporal evolution of individual's trajectories. The following chapter 4 presents some reflections about the idea of cohesion and cohesive subgroups specific to the case of two-mode networks. Based on the affiliation matrices, the analysis of local clustering through bi-cliques offers an attempt to analyse the mechanism of selecting accomplices while taking into account time. Chapter 5 is concerned with the concept of centrality of individuals involved in flows of knowledge exchanges. The theoretical and analytical framework helps in elaborating how individuals share their acquired hands-on experiences with others by attending joint task activities over time. Chapter 6 provides an application of the approaches introduced in the preceding chapters to the specific case of the Noordin Top terrorist network. Here, the knowledge of experience flow centrality measure opens up a new way to quantify the transmission of information and investigate the formation of the criminal capital. Finally, the last Chapter 7 presents some future research extensions by illustrating the versatility of the proposed approaches in order to provide new insights for the understanding of criminals' behaviours.
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Benigni, Matthew Curran. "Detection and Analysis of Online Extremist Communities." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/949.
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Online social networks have become a powerful venue for political activism. In many cases large, insular online communities form that have been shown to be powerful diffusion mechanisms of both misinformation and propaganda. In some cases these groups users advocate actions or policies that could be construed as extreme along nearly any distribution of opinion, and are thus called Online Extremist Communities (OECs). Although these communities appear increasingly common, little is known about how these groups form or the methods used to influence them. The work in this thesis provides researchers a methodological framework to study these groups by answering three critical research questions: How can we detect large dynamic online activist or extremist communities? What automated tools are used to build, isolate, and influence these communities? What methods can be used to gain novel insight into large online activist or extremist communities? These group members social ties can be inferred based on the various affordances offered by OSNs for group curation. By developing heterogeneous, annotated graph representations of user behavior I can efficiently extract online activist discussion cores using an ensemble of unsupervised machine learning methods. I call this technique Ensemble Agreement Clustering. Through manual inspection, these discussion cores can then often be used as training data to detect the larger community. I present a novel supervised learning algorithm called Multiplex Vertex Classification for network bipartition on heterogeneous, annotated graphs. This methodological pipeline has also proven useful for social botnet detection, and a study of large, complex social botnets used for propaganda dissemination is provided as well. Throughout this thesis I provide Twitter case studies including communities focused on the Islamic State of Iraq and al-Sham (ISIS), the ongoing Syrian Revolution, the Euromaidan Movement in Ukraine, as well as the alt-Right.
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Dobson, Lucas E. "Security analysis of session initiation protocol." Thesis, Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Jun/10Jun%5FDobson.pdf.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, June 2010.Thesis Advisor(s): Dinolt, George ; Eagle, Chris. "June 2010." Description based on title screen as viewed on July 13, 2010. Author(s) subject terms: Session initiation protocol, voice over IP, information security, siproxd, linphone, Qutecom, osip, eXosip Includes bibliographical references (p. 77-78). Also available in print.
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Crowley, Patrick. "Design and analysis of architectures for programmable network processing systems /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/6991.
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Chevalier, Philippe B., and Lawrence M. Wein. "Scheduling Networks of Queues: Heavy Traffic Analysis of a Multistation Closed Network." Massachusetts Institute of Technology, Operations Research Center, 1990. http://hdl.handle.net/1721.1/5319.
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We consider the problem of finding an optimal dynamic priority sequencing policy to maximize the mean throughput rate in a multistation, multiclass closed queueing network with general service time distributions and a general routing structure. Under balanced heavy loading conditions, this scheduling problem can be approximated by a control problem involving Brownian motion. Although a unique, closed form solution to the Brownian control problem is not derived, an analysis of the problem leads to an effective static sequencing policy, and to an approximate means of comparing the relative performance of arbitrary static policies. Three examples are given that illustrate the effectiveness of our procedure.
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Knight, Louise Anne. "The case for network learning : an analysis of learning by interorganizational networks." Thesis, University of Bath, 2002. http://eprints.aston.ac.uk/18542/.
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Johansson, Peter. "Dynamic Co-authorship Network Analysis with Applications to Survey Metadata." Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96794.
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Co-authorship networks are a particular sort of social networks representing authors collaborating on joint publications. Such networks are studied within the fields of bibliometrics and scientometrics. While it is possible to analyze co-authorship networks in their entirety, certain analytical tasks would benefit from representing such networks as dynamic graphs, which incorporate a temporal dimension and capture structural transformations unfolding over time. The importance of dynamic graphs has emerged in recent years, in graph theory at large as well as within application domains such as social sciences, for instance.Research regarding dynamic graphs has been identified as one of the major challenges within network theory since they are particularly useful for describing real-world systems.This thesis project revolves around dynamic co-authorship network analysis algorithms, which aim to extract various temporal aspects regarding author collaborations.It is the result of a proposal by the ISOVIS group at Linnaeus University, which is active within the fields of exploratory data analysis and information visualization, including the problem of visual analysis of scientific publication data. The algorithms developed in this project extract analytical data such as (1) joint publications among pairs of authors, (2) temporal trends on connected components (groups of authors) along with network centrality measurements, and (3) major events regarding emergence, mergers, and splits of connected components over time. Together with domain experts, the analysis regarding usability, performance, and scalability of the algorithms took place as part of the evaluation process to assure that the result met the needs which instigated this thesis project. The application of the algorithms on real data sets provided by the ISOVIS group was useful concerning the evaluation of the usability domain. In contrast, customized synthetic data sets was an excellent tool for evaluating performance and scalability.
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Haiba, Mohamed Salem. "A study and implementation of the network flow problem and edge integrity of networks." Virtual Press, 1991. http://liblink.bsu.edu/uhtbin/catkey/834644.
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Fundamental problems in graph theory are of four types existence, construction, enumeration and optimization problems. Optimization problems lie at the interface between computer science and the field of operations research and are of primary importance in decision-making. In this thesis, two optimization problems are studied: the edge-integrity of networks and the network flow problem. An implementation of the corresponding algorithms is also realized.The edge integrity of a communication network provides a way to assess the vulnerability of the network to disruption through the destruction or failure of some of its links. While the computation of the edge-integrity of graphs in general has been proven to be NPcomplete, a recently published paper was devoted to a good algorithm using a technique of edge separation sequence for computing the edge integrity of trees. The main results of this paper will be presented and an implementation of this algorithm is achieved.The network flow problem models a distribution system in which commodities are flowing through an interconnected network. The goal is to find a maximum feasible flow and its value, given the capacity constraints for each edge. The three majors algorithms for this problem (Ford -Fulkerso n, Edmonds-Karp method, MPKM algorithm) are discussed, their complexities compared and an implementation of the Ford-Fulkerson and the MPKM algorithms is presented.Department of Computer Science
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Köstinger, Harald. "ViNCent – Visualization of NetworkCentralities." Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-10793.
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In the area of information visualization social or biological networks are visualized ina way so that they can be explored easily and one can get more information about thestructure of the network out of it. The use of network centralities in the field of network analysis plays an importantrole when it comes to the rating of the relative importance of vertices within the networkstructure based on the neighborhood of them. Such a single network can be renderedeasily by the use of standard graph drawing algorithms. But it is not only the explorationof one centrality which is important. Furthermore, the comparison of two or more of themis important to get some further meaning out of it. When visualizing the comparisonof two or more network centralities we are facing new problems of how to visualizethem in a way to get out the most meaning of it. We want to be able to track all thechanges in the networks between two centralities as well as visualize the single networksas best as possible. In the life sciences centrality measures help scientists to understand theunderlying biological processes and have been successfully applied to different biologicalnetworks. The aim of the thesis is it to overcome those problems and to come up with a new solutionof how to visualize networks and its centralities. This thesis introduces a new way ofrendering networks including their centrality values along a circular view. Researches canthen be focused on the exploration of the centrality values including the network structure,without dealing with visual clutter or occlusions of nodes. Furthermore, filtering based instatistical data concerning the datasets and centrality values support this.
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Weinstein, Lee. "Scale free networks and their power law distribution." Diss., Connect to the thesis, 2005. http://hdl.handle.net/10066/3880.
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Hultin, Alex. "Sustaining interdisciplinary research : a multilayer perspective." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767571.
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Interdisciplinary Research (IDR) has received a lot of attention from academics, policy-makers, and decision-makers alike. RCUK invests £3 billion in research grants each year (RCUK 2017); half of the grants are provided to investigators who hail from different departments. There is mounting awareness of the challenges facing IDR, and a large body of literature trying to establish how IDR can be analysed (Davidson 2015, Yegros-Yegros, Rafols et al. 2015). Of these, the majority have been qualitative studies and it has been noticed that there is a distinct lack of quantitative studies that can be used to identify how to enable IDR. The literature shows that many of the barriers to IDR can be classified as either cultural or administrative (Katz and Martin 1997, Cummings and Kiesler 2005, Rafols 2007, Wagner, Roessner et al. 2011), neither of which are easily changed over a short period of time. The perspective taken in this research is that change can be affected by enabling the individuals who conduct IDR. Herein lies the main challenge; how can these future leaders of IDR be identified so that they can be properly supported. No existing datasets were deemed suitable for the purpose, and a new dataset was created to analyse IDR. To isolate dynamics within an organisation, hard boundaries were drawn around research-organisations. The University of Bath journal co-authorship dataset 2000-2017 was determined to be suitable for this purpose. From this dataset a co-authorship network was created. To analyse this, established models from literature were adapted and used to identify differences in disciplinary and interdisciplinary archetypes. This was done through a correlational study. No statistically significant differences between such author archetypes were found. It was therefore concluded that an alternative approach was necessary. By adapting the networks framework to account for different types of links between edges, a multilayer perspective was adopted. This resulted in a rank-3 tensor, node-aligned framework being proposed, allowing disciplines to be represented in the network. By using this framework to construct the University of Bath multiplex co-authorship network, an exemplar structure was established through use of a series of proposed structural metrics. A growth model was proposed and successfully recreated the structure and thereby uncovered mechanics affecting real-world multiplex networks. This highlighted the importance of node entities and the layer closeness centrality. This implies that it is very difficult to carry over benefits across disciplines, and that some disciplines are better suited to share and adapt knowledge than others. The growth model also allowed an analytical expression for the rate of change of disciplinary degree, thereby providing a model for who is most likely to enable and sustain IDR.
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Liu, Mengxin. "Generative Neural Network for Portfolio Optimization." Thesis, Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-53027.
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This thesis aims to overcome the drawbacks of traditional portfolio optimization by employing Generative Deep Neural Networks on real stock data. The proposed framework is capable of generating return data that have similar statistical characteristics as the original stock data. The result is acquired using Monte Carlo simulation method and presented in terms of individual risk. This method is tested on real Swedish stock market data. A practical example demonstrates how to optimize a portfolio based on the output of the proposed Generative Adversarial Networks.
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Fidalgo, Patrícia Seferlis Pereira. "Learning networks and moodle use in online courses: a social network analysis study." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8862.
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Dissertação para obtenção do Grau de Doutor em Ciências da Educação Especialidade em Tecnologias, Redes e Multimédia na Educação e FormaçãoThis research presents a case study on the interactions between the participants of the forums of four online undergraduate courses from the perspective of social network analysis (SNA). Due to lack of studies on social networks in online learning environments in higher education in Portugal we have choose a qualitative structural analysis to address this phenomenon. The context of this work was given by the new experiences in distance education (DE) that many institutions have been making. Those experiences are a function of the changes in educational paradigms and due to a wider adoption of Information and Communication Technologies (ICT) from schools as well as to the competitive market. Among the technologies adopted by universities are the Learning Management Systems (LMSs) that allow recording, storing and using large amounts of relational data about their users and that can be accessed through Webtracking. We have used this information to construct matrices that allowed the SNA. In order to deepen knowledge about the four online courses we were studying we have also collect data with questionnaires and interviews and we did a content analysis to the participations in the forums. The three main sources of data collection led us to three types of analysis: SNA, statistical analysis and content analysis. These types of analysis allowed, in turn, a three-dimensional study on the use of the LMS: 1) the relational dimension through the study of forums networks and patterns of interaction among participants in those networks, 2) the dimension relative to the process of teaching and learning through content analysis of the interviews; 3) and finally the dimension related to the participants' perceptions about the use of LMS for educational purposes and as a platform for creating social networks through the analysis of questionnaires.With the results obtained we carried out a comparative study between the four courses and tried to present a reflection on the Online Project of the University as well as possible causes that led to what was observed. We have finished with a proposal of a framework for studying the relational aspects of online learning networks aimed at possible future research in this area.
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Trier, Matthias. "Towards a Social Network Intelligence Tool for visual Analysis of Virtual Communication Networks." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-140161.
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Communities of Practice regularly utilize virtual means of communication. The according software support provides its members with many sophisticated features for generating content and for communicating with each other via the internet or intranet. However, functionalities to monitor, assess, coordinate, and communicate the quality and development of the underlying electronic networks of experts are frequently missing. To meet this need of increased manageability, this contribution introduces a Social Network Intelligence software approach which aims at supporting the comprehension of the structure and value of electronic communities by automatically extracting and mining available electronic data of various types of virtual communication networks, like e-mail archives, discussion groups, or instant messaging communication. Experimental structural visualizations employing Social Network Analysis methods are combined with Keyword Extraction to move towards a Social Network Intelligence approach which generates transparency of complex virtual communication networks. Together with a comprehensive visualization method, an approach for software-supported communication network measurement and evaluation is suggested. It supports the identification of important participants, topics, or clusters in the network, evaluates the interpersonal communication structure and visually traces the evolvement of the knowledge exchange over time.
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Trier, Matthias. "Towards a Social Network Intelligence Tool for visual Analysis of Virtual Communication Networks." Technische Universität Dresden, 2006. https://tud.qucosa.de/id/qucosa%3A27871.
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Communities of Practice regularly utilize virtual means of communication. The according software support provides its members with many sophisticated features for generating content and for communicating with each other via the internet or intranet. However, functionalities to monitor, assess, coordinate, and communicate the quality and development of the underlying electronic networks of experts are frequently missing. To meet this need of increased manageability, this contribution introduces a Social Network Intelligence software approach which aims at supporting the comprehension of the structure and value of electronic communities by automatically extracting and mining available electronic data of various types of virtual communication networks, like e-mail archives, discussion groups, or instant messaging communication. Experimental structural visualizations employing Social Network Analysis methods are combined with Keyword Extraction to move towards a Social Network Intelligence approach which generates transparency of complex virtual communication networks. Together with a comprehensive visualization method, an approach for software-supported communication network measurement and evaluation is suggested. It supports the identification of important participants, topics, or clusters in the network, evaluates the interpersonal communication structure and visually traces the evolvement of the knowledge exchange over time.
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Bockholt, Mareike [Verfasser], and Katharina A. [Akademischer Betreuer] Zweig. "Analysis of network flows in complex networks / Mareike Bockholt ; Betreuer: Katharina A. Zweig." Kaiserslautern : Technische Universität Kaiserslautern, 2021. http://d-nb.info/1238074545/34.
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