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Torres, Guardia Luis Ernesto, i Nelson N. Lacerda. "Multiple objetive network flow problems". Pontificia Universidad Católica del Perú, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/97276.
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In this work, it is presented the multiple objective networkflow problems. This kind of problem is converted into singleo bjective problem and solved by using the primal dual interior point method. The linear system associated to the interior point method is solved by using the Cholesky decomposition, implemented in MATLAB code. Networks of different dimensions are constructed and the computational results show the efficiency of the mentioned interior point method for solving multiple objective network flow problems.
2
Pablo, Rodriguez Juan Manuel. "Multiple Target Detection and Tracking in a Multiple Camera Network". Thesis, KTH, Kommunikationsnät, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175884.
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Given synchronized video sequences from a number of cameras withoverlapping fields of view, the detection and tracking of a prioriunknownnumber of individuals entering a determined area is considered,showingthat a generative model can accurately follow the individuals and handleeffectively such problems as occlusions in each view independently. Theaim of this thesis is to implement the exchange of information betweenthe cameras where the detection and tracking processes take place. Theinputs are obtained from synchronized videos and the frames are takenindividually to treat them as independent images. The proposed algo-rithm was implemented in MATLAB and results obtained on a personalcomputer are presented. The results show that the algorithm achievesgood tracking accuracy, has relatively low computational complexity, andat the same time it allows to observe the communication requirementsbetween the cameras and the processing node.
3
Smith, Anna Lantz. "Statistical Methodology for Multiple Networks". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492720126432803.
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Orimolade, Joseph Folorunsho. "Access network selection schemes for multiple calls in next generation wireless networks". Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25380.
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There is an increasing demand for internet services by mobile subscribers over the wireless access networks, with limited radio resources and capacity constraints. A viable solution to this capacity crunch is the deployment of heterogeneous networks. However, in this wireless environment, the choice of the most appropriate Radio Access Technology (RAT) that can Tsustain or meet the quality of service (QoS) requirements of users' applications require careful planning and cost efficient radio resource management methods. Previous research works on access network selection have focused on selecting a suitable RAT for a user's single call request. With the present request for multiple calls over wireless access networks, where each call has different QoS requirements and the available networks exhibit dynamic channel conditions, the choice of a suitable RAT capable of providing the "Always Best Connected" (ABC) experience for the user becomes a challenge. In this thesis, the problem of selecting the suitable RAT that is capable of meeting the QoS requirements for multiple call requests by mobile users in access networks is investigated. In addressing this problem, we proposed the use of Complex PRoprtional ASsesment (COPRAS) and Consensus-based Multi-Attribute Group Decision Making (MAGDM) techniques as novel and viable RAT selection methods for a grouped-multiple call. The performance of the proposed COPRAS multi-attribute decision making approach to RAT selection for a grouped-call has been evaluated through simulations in different network scenarios. The results show that the COPRAS method, which is simple and flexible, is more efficient in the selection of appropriate RAT for group multiple calls. The COPRAS method reduces handoff frequency and is computationally inexpensive when compared with other methods such as the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Simple Additive Weighting (SAW) and Multiplicative Exponent Weighting (MEW). The application of the proposed consensus-based algorithm in the selection of a suitable RAT for group-multiple calls, comprising of voice, video-streaming, and file-downloading has been intensively investigated. This algorithm aggregates the QoS requirement of the individual application into a collective QoS for the group calls. This new and novel approach to RAT selection for a grouped-call measures and compares the consensus degree of the collective solution and individual solution against a predefined threshold value. Using the methods of coincidence among preferences and coincidence among solutions with a predefined consensus threshold of 0.9, we evaluated the performance of the consensus-based RAT selection scheme through simulations under different network scenarios. The obtained results show that both methods of coincidences have the capability to select the most suitable RAT for a group of multiple calls. However, the method of coincidence among solutions achieves better results in terms of accuracy, it is less complex and the number of iteration before achieving the predefined consensus threshold is reduced. A utility-based RAT selection method for parallel traffic-streaming in an overlapped heterogeneous wireless network has also been developed. The RAT selection method was modeled with constraints on terminal battery power, service cost and network congestion to select a specified number of RATs that optimizes the terminal interface utility. The results obtained show an optimum RAT selection strategy that maximizes the terminal utility and selects the best RAT combinations for user's parallel-streaming for voice, video and file-download.
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Forsgren, Gustav. "Multiple Synchronized Video Streams on IP Network". Thesis, Linköpings universitet, Informationskodning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-108491.
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Video surveillance today can look very different depending on the objective and on the location where it is used. Some applications need a high image resolution and frame rate to carefully analyze the vision of a camera, while other applications could use a poorer resolution and a lower frame rate to achieve it's goals. The communication between a camera and an observer depends much on the distance between them and on the contents. If the observer is far away the information will reach the observer with delay, and if the medium carrying the information is unreliable the observer has to have this in mind. Lost information might not be acceptable for some applications, and some applications might not need it's information instantly. In this master thesis, IP network communication for an automatic tolling station has been simulated where several video streams from different sources have to be synchronized. The quality of the images and the frame rate are both very important in these types of surveillance, where simultaneously exposed images are processed together. The report includes short descriptions of some networking protocols, and descriptions of two implementations based on the protocols. The implementations were done in C++ using the basic socket API to evaluate the network communication. Two communication methods were used in the implementations, where the idea was to push or to poll images. To simulate the tolling station and create a network with several nodes a number of Raspberry Pis were used to execute the implementations. The report also includes a discussion about how and which video/image compression algorithms the system might benefit of. The results of the network communication evaluation shows that the communication should be done using a pushing implementation rather than a polling implementation. A polling method is needed when the transportation medium is unreliable, but the network components were able to handle the amount of simultaneous sent information very well without control logic in the application.
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Kondam, Sudhir Chander Reddy. "Deploying multiple sensor applications in a network". Kansas State University, 2010. http://hdl.handle.net/2097/6990.
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Master of ScienceDepartment of Computing and Information Sciences
Gurdip Singh
TinyOS is an open-source component based operating system designed for highly memory constrained wireless embedded sensor network. TinyOS includes interfaces and components for communication management, routing and data acquisition tools to be refined further for custom applications. This project aims at developing a system which detects overlapping paths for data collection in different applications in the network and utilizing that information for efficient data acquisition. This prevents a reconfiguring the entire network of wireless sensor nodes (called motes) for each new application request. The application for initial or first data acquisition request tries to build the tree architecture on motes in the network where each node in the tree knows its immediate parent and children. The application builds the tree routed at the base station for the initial request and each intermediate node sends data to its parent when the data request is made. Each base station can request Light, Temperature and Passive Infrared sensory data from all or a subset of motes present in the system. When a new base station comes and connects to the network through a mote/node in the tree, the system reconfigures only those parts of the tree built in the initial phase which do not overlap with the tree required for the new base station as the root, all the other overlapping parts of the tree are left unchanged. We present experimental result to illustrate the efficiency of the approach.
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McNeil, Patrick. "Integrating Multiple Modalities into Deep Learning Network". NSUWorks, 2017. http://nsuworks.nova.edu/gscis_etd/1004.
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Deep learning networks in the literature traditionally only used a single input modality (or data stream). Integrating multiple modalities into deep learning networks with the goal of correlating extracted features was a major issue. Traditional methods involved treating each modality separately and then writing custom code to combine the extracted features. Current solutions for small numbers of modalities (three or less) showed there are multiple architectures for modality integration. With an increase in the number of modalities, the “curse of dimensionality” affects the performance of the system. The research showed current methods for larger scale integrations required separate, custom created modules with another integration layer outside the deep learning network. These current solutions do not scale well nor provide good generalized performance. This research report studied architectures using multiple modalities and the creation of a scalable and efficient architecture.
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DI, BRISCO AGNESE MARIA. "Statistical Network Analysis: a Multiple Testing Approach". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/96090.
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The problem of identifying connections between nodes in a network model is of fundamental importance in the analysis of brain networks because each node represents a specific brain region that can potentially be connected to other brain regions by means of functional relations; the dynamical behavior of each node can be quantified by adopting a correlation measure among time series.
In this contest, the whole set of links between nodes in a network can be represented by means of an adjacency matrix with high dimension, that can be obtained by performing a huge number of simultaneous tests on correlations.
In this regard, the Thesis has dealt with the problem of multiple testing in a Bayesian perspective, by examining in depth the “Bayesian False Discovery Rate” (FDR), already defined in Efron, and by introducing the “Bayesian Power” (BP). The behavior of the FDR and BP estimators has been analyzed both with asymptotic theory and with Monte Carlo simulations; furthermore, it has been investigated the robustness of the proposed estimators by simulating specific pattern of dependencies among the p-values associated to the multiple comparisons.
Such a multiple testing approach, that allows to control both FDR and BP, has been applyied to a dataset provided by the Milan Center for Neuroscience (NeuroMi). Once selected a sample of 70 participants, classified properly into young subjects and elderly subjects, subject by subject network models have been constructed in order to verify two alternative theories about changes in the pattern of functional connectivity as time goes by, namely the de-differentiation hypothesis versus the localization hypothesis.
This objective has been achieved by selecting some proper network measures in order to verify the original hypotheses about the pattern of functional connectivity in the elderly’s group and in the group of young subjects, and by constructing some ad-hoc measures.
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Zhao, Qian Effros Michelle. "Network source coding : theory and code design for broadcast and multiple access networks /". Diss., Pasadena, Calif. : California Institute of Technology, 2003. http://resolver.caltech.edu/CaltechETD:etd-05302003-125004.
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Suryadevara, Usha. "Buffer management in tone allocated multiple access protocol". [Gainesville, Fla.] : University of Florida, 2001. http://purl.fcla.edu/fcla/etd/UFE0000357.
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Thesis (M.S.)--University of Florida, 2001.Title from title page of source document. Document formatted into pages; contains vi, 78 p.; also contains graphics. Includes vita. Includes bibliographical references.
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saha, dhrubajyoti. "PLAYBACK BUFFERING AND CONTROL FOR LINEAR MULTIPLE INPUT MULTIPLE OUTPUT NETWORK CONTROL SYSTEMS". Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1363411715.
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Sarkar, Souradip. "Multiple clock domain synchronization for network on chips". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/S_Sarkar_112907.pdf.
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Kivisäkk, Pia. "Studies on the cytokine network in multiple sclerosis /". Stockholm, 1998. http://diss.kib.ki.se/1998/91-628-3229-8/.
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Wallentinsson, Emma Wallentinsson. "Multiple Time Series Forecasting of Cellular Network Traffic". Thesis, Linköpings universitet, Statistik och maskininlärning, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-154868.
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The mobile traffic in cellular networks is increasing in a steady rate as we go intoa future where we are connected to the internet practically all the time in one wayor another. To map the mobile traffic and the volume pressure on the base stationduring different time periods, it is useful to have the ability to predict the trafficvolumes within cellular networks. The data in this work consists of 4G cellular trafficdata spanning over a 7 day coherent period, collected from cells in a moderately largecity. The proposed method in this work is ARIMA modeling, in both original formand with an extension where the coefficients of the ARIMA model are re-esimated byintroducing some user characteristic variables. The re-estimated coefficients produceslightly lower forecast errors in general than a isolated ARIMA model where thevolume forecasts only depends on time. This implies that the forecasts can besomewhat improved when we allow the influence of these variables to be a part ofthe model, and not only the time series itself.
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Sgrignoli, Paolo. "The World Trade Web: a multiple-network perspective". Thesis, IMT Alti Studi Lucca, 2014. http://e-theses.imtlucca.it/137/1/Sgrignoli_phdthesis.pdf.
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International Trade (IT) plays a fundamental role in today’s
economy: by connecting world countries production and consumption processes, it radically contributes in shaping their economy and development path. Although its evolving structure and determinants have been widely analyzed in the literature, much less has been done to understand its interplay with other complex phenomena. The aim of this work is, precisely in this direction, to study the relations of IT with International Migration (IM) and Foreign Direct Investments (FDI). In both cases the procedure used is to first approach the problem
in a multiple-networks perspective and than deepen the
analysis by using ad hoc econometrics techniques.
With respect to IM, a general positive correlation with IT is highlighted and product categories for which this effect is stronger are identified and cross-checked with previous classifications. Next, employing spatial econometric techniques and proposing a new way to define country neighbors based on the most intense IM flows, direct/indirect network effects are studied and a stronger competitive effect of third country migrants is identified for a specific product class. In the case of FDI, first correlations between the two networks are identified, highlighting how they can be mostly explained by countries economic/demographic size and geographical distance. Then, using the Heckman selection model with a gravity equation, (non-linear) components arising from distance, position in the Global Supply Chain and presence of Regional Trade Agreements are studied. Finally, it is shown how IT and FDI correlation changes with sectors: they are complements in manufacturing, but substitutes in services.
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Millereau, Pierre Michel. "Large Strain and Fracture of Multiple Network Elastomers". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066082/document.
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Durant ce travail, nous avons étudié les propriétés mécaniques et de fracture d'élastomères à réseaux multiples synthétisés par des étapes successives de gonflement/polymérisation inspirées de l'architecture moléculaire développée par Gong pour les doubles réseaux hydrogels. Une méthode de synthèse plus versatile a été utilisée pour varier de façon continue le pré-étirement isotrope du premier réseau λ0, qui contrôle le module d'Young et le durcissement. Dans le cas d'une dilution importante du premier réseau (<10%), une scission moléculaire apparaît à grande déformation dans le réseau pré-étiré sans rompre le matériau. Le taux de dilution contrôle la quantité d’endommagement et donc la pente de la courbe contrainte-déformation. Finalement, pour les systèmes les plus dilués (<3%), une striction est observée au-dessus d’un seuil de contrainte. Changer le taux de réticulant du premier réseau ou les monomères utilisés ont conduit par ailleurs à l’obtention de comportements mécaniques similaires. L’énergie de fracture Γ est une fonction croissante de λ0. Des techniques de visualisation locale comme la Corrélation d’Image Numérique et l’intégration de molécules méchanoluminescentes ont été utilisées pour décrire une zone d’endommagement en tête de fissure dont la taille augmente avec λ0. Enfin, le mécanisme de renforcement des élastomères à réseaux multiples a pu être partiellement décrit dans le contexte du modèle de Brown sur les doubles réseauxWe investigated systematically the mechanical and fracture properties of multiple network elastomers synthesized by successive swelling/polymerization steps inspired by the molecular architecture of Gong’s double network gels. A more versatile synthesis method was used to vary continuously the isotropic degree of prestretching λ0 of the first network resulting in a wider range of mechanical behaviours, where λ0 controls the Young’s modulus at small strain and the strain hardening at large strain. If the first network is diluted enough (<10%) molecular bond breakage occurs in this prestretched network at high strain while avoiding sample failure. The degree of dilution controls the amount of damage and therefore the slope of the stress-strain curve. Finally, for the most diluted systems (<3%), a yield stress and a necking phenomenon was observed. Changing the degree of crosslinking of the first network or the monomers used led to the same qualitative mechanical behaviour. The fracture energy Γ was shown to be an increasing function of λ0 however different regimes could be distinguished with macroscopic fracture occurring before or after bulk damage was detected. Visualisation techniques such as Digital Image Correlation and embedded mechanoluminescent molecules were used to map a damage zone in front of the crack tip, the size of which increased with λ0. Finally, the toughening mechanism of the multiple network elastomers could be understood in a nearly quantitative way within the framework of Brown's model of fracture of double network gels
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Millereau, Pierre Michel. "Large Strain and Fracture of Multiple Network Elastomers". Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066082.pdf.
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Durant ce travail, nous avons étudié les propriétés mécaniques et de fracture d'élastomères à réseaux multiples synthétisés par des étapes successives de gonflement/polymérisation inspirées de l'architecture moléculaire développée par Gong pour les doubles réseaux hydrogels. Une méthode de synthèse plus versatile a été utilisée pour varier de façon continue le pré-étirement isotrope du premier réseau λ0, qui contrôle le module d'Young et le durcissement. Dans le cas d'une dilution importante du premier réseau (<10%), une scission moléculaire apparaît à grande déformation dans le réseau pré-étiré sans rompre le matériau. Le taux de dilution contrôle la quantité d’endommagement et donc la pente de la courbe contrainte-déformation. Finalement, pour les systèmes les plus dilués (<3%), une striction est observée au-dessus d’un seuil de contrainte. Changer le taux de réticulant du premier réseau ou les monomères utilisés ont conduit par ailleurs à l’obtention de comportements mécaniques similaires. L’énergie de fracture Γ est une fonction croissante de λ0. Des techniques de visualisation locale comme la Corrélation d’Image Numérique et l’intégration de molécules méchanoluminescentes ont été utilisées pour décrire une zone d’endommagement en tête de fissure dont la taille augmente avec λ0. Enfin, le mécanisme de renforcement des élastomères à réseaux multiples a pu être partiellement décrit dans le contexte du modèle de Brown sur les doubles réseauxWe investigated systematically the mechanical and fracture properties of multiple network elastomers synthesized by successive swelling/polymerization steps inspired by the molecular architecture of Gong’s double network gels. A more versatile synthesis method was used to vary continuously the isotropic degree of prestretching λ0 of the first network resulting in a wider range of mechanical behaviours, where λ0 controls the Young’s modulus at small strain and the strain hardening at large strain. If the first network is diluted enough (<10%) molecular bond breakage occurs in this prestretched network at high strain while avoiding sample failure. The degree of dilution controls the amount of damage and therefore the slope of the stress-strain curve. Finally, for the most diluted systems (<3%), a yield stress and a necking phenomenon was observed. Changing the degree of crosslinking of the first network or the monomers used led to the same qualitative mechanical behaviour. The fracture energy Γ was shown to be an increasing function of λ0 however different regimes could be distinguished with macroscopic fracture occurring before or after bulk damage was detected. Visualisation techniques such as Digital Image Correlation and embedded mechanoluminescent molecules were used to map a damage zone in front of the crack tip, the size of which increased with λ0. Finally, the toughening mechanism of the multiple network elastomers could be understood in a nearly quantitative way within the framework of Brown's model of fracture of double network gels
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Traore, Oumar, i Stephen Gwanvoma. "Mixed Network Clustering with Multiple Ground Stations and Nodes Preferences". International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604253.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaThis paper presents a method for managing a Mixed Network with multiple ground stations and Test Articles (TA) preferences. The main difference between a Ground Station (cellular) network and the over the horizon (ad-hoc) network is that the ad-hoc method has no fixed infrastructure. This paper presents the computation and performance of a clustering technique for mobile nodes within the simulated mixed network environment with multiple ground stations and users preferences for those ground stations. This includes organization for multiple ground stations and for TA's gravitating toward a ground station of their choice on the basis of service and performance.
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Duff, Kevin Craig. "Network-layer reservation TDM for ad-hoc 802.11 networks". Thesis, Rhodes University, 2008. http://eprints.ru.ac.za/1146/.
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Liston, John Richard. "Measuring User-Perceived Internet Performance in Multiple Locations". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4803.
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Measurement studies of Internet performance are critical for
validating or refuting widely held beliefs about Web behavior, and for
shedding light on unknown behaviors. Results from these studies can
guide Internet architects in making decisions that affect Internet
Service Providers (ISPs), content providers and end-users. Examples of
decisions that can benefit from measurement information include
provisioning network capacity, placing Domain Name System (DNS) and
Web servers, and tuning parameters of transport layer protocols.
Internet protocols and services may exhibit different performance
characteristics when observed from different locations in the Internet
topology; to date, however, there has been little work investigating
the differences in these characteristics from multiple vantage
points. Typically, performance studies present results of measurements
taken in only one or two locations. Some of the reasons for the lack
of work in this area are the following. First, performance
measurement was not a high priority of Internet design and was not
built into the network architecture. Second, it is difficult to obtain
the necessary level of privilege at many different locations in the
Internet topology to perform measurement studies. Finally, high
expectations for real-time Internet performance is a relatively recent
phenomenon.
In this thesis we develop several methods for gathering
Internet performance data from multiple locations throughout the
world, and to analyze data gathered. Our focus is on the protocols
and services that support the World Wide Web.
In the first method we utilize a modified Web proxy. Our proxy
captures and logs fine-grained performance information on a per-user
basis. Our second method is to create and deploy a measurement package
for examining DNS performance. We modified the BIND DNS server and
packaged it with a script to drive the data collection. Our final
method is to create and distribute an application to be run at user
sites worldwide. One of the primary tasks of the application is to
provide performance data from each instance of the application
executing at locations throughout Internet topology. We can use the
information provided by this application to examine user-perceived
Internet performance throughout the globe.
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Bahceci, Israfil. "Multiple-Input Multiple-Output Wireless Systems: Coding, Distributed Detection and Antenna Selection". Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-022321/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.Altunbasak, Yucel, Committee Chair ; Mersereau, Russell M., Committee Member ; Fekri, Faramarz, Committee Member ; Smith, Glenn, Committee Member ; Huo, Xiaoming, Committee Member. Includes bibliographical references.
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Brown, Trevor Junior. "Time division multiple access/code division multiple access for the optical local access network". Thesis, Manchester Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243716.
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Traskov, Danail [Verfasser]. "Network Coding for the Multiple Access Layer / Danail Traskov". München : Verlag Dr. Hut, 2010. http://d-nb.info/1009485326/34.
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Franzén, Nicklas. "Network Sockets, Threading or select for multiple concurrent connections". Thesis, Blekinge Tekniska Högskola, Avdelningen för för interaktion och systemdesign, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-5501.
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The purpose of the thesis is to present a foundation for selecting an appropriate model while building a concurrent network server, focusing on a comparison between a select() based server and one thread for each connection. The test conducted herein is based two echo servers ( the message sent is echoed back to the sender ) and the time they take to serve a number of clients. The programs written for it are run on both Windows and Linux to show if the choice of platform affects the methods efficiency. Also looking at the return time of select() when we have a number of sockets, as well the time it takes to create a set number of threads. The conclusion drawn in this thesis is that for up to 512 sockets there is really no significant difference in the time it takes for the test program to return, this was true for both the Windows and the Linux test. Note however that the threading implementation requires much more memory than the select based one. So in the end it is basically up to personal preferences.E-Mail: Nicklas.Franzen@gmail.com Mobile: 0703-506904
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Lin, Yu-pin. "Multiple-point variance analysis for groundwater monitoring network design". Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/19511.
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NUNES, VIVIAN DE ARAUJO DORNELAS. "EFFECTS OF CONTACT NETWORK RANDOMNESS ON MULTIPLE OPINION DYNAMICS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=30466@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
PROGRAMA DE EXCELENCIA ACADEMICA
Muitas vezes enfrentamos o desafio de escolher entre diferentes opções com atratividade semelhante como, por exemplo, na escolha de um candidato parlamentar, na escolha de um filme ou ao comprar um produto no supermercado. A fim de estudar a distribuição das preferências em tais situações, podemos considerar dinâmicas de opinião (com diversas opções possíveis, contemplando também os casos em que há indecisão) em redes. Neste trabalho, utilizamos duas dinâmicas distintas: uma envolvendo o contágio direto de cada sítio para a sua vizinhança (regra A) e a outra onde a opinião de cada sítio é definida pela maioria relativa local (regra B). A topologia da rede de contatos pode ter um efeito importante sobre a distribuição final de opiniões. Utilizamos as redes de Watts-Strogatz e, em particular, estamos interessados em investigar a contribuição da aleatoriedade p da rede no resultado final das dinâmicas. Dependendo das propriedades estruturais da rede e das condições iniciais, podemos ter diferentes resultados finais: equipartição de preferências, consenso e situações onde a indecisão é relevante. O papel da aleatoriedade da rede é não trivial: para um número pequeno de opiniões, as regras A e B (esta última com atualização síncrona) apresentam um valor ótimo de p, onde o predomínio da opinião vencedora é máximo. Já para a regra da pluralidade com atualização assíncrona, o aumento do número de atalhos pode até mesmo promover situações de consenso. Além disso, as duas dinâmicas (e seus diferentes modos de atualização) coincidem para baixa desordem da rede, mas diferem para graus de desordem maiores. Observaremos também que a quantidade de iniciadores diminui a fração da opinião vencedora para todas as dinâmicas e atenua o máximo local que aparece na região de mundo pequeno.
People often face the challenge of choosing amongst different options with similar attractiveness, such as when choosing a parliamentary candidate, a movie or buying a product in the supermarket. In order to study the distribution of preferences in such situations, we can consider opinion dynamics (where different options are available as well as the undecided state) in network. In this work, we use two different opinion dynamics: one involving the direct contagion from each site to its neighborhood (rule A) and another where the opinion of each site is defined by the local relative majority (rule B). The contact network topology can have a important effect in the final distribution of opinions. We use the Watts-Strogatz network and, in particular, we are interested in investigating the contribution of the network randomness p in the output of the dynamics. Depending on the structural properties of the network and the initial conditions, the final distribution can be: equipartition of preferences, consensus and situations where indecision is relevant. The role of network randomness is nontrivial: for a small number of opinions, the rules A and B (the latter with synchronous update) present an optimum value of p, where the predominance of a winning opinion is maximal. Moreover, for the plurality rule with asynchronous update, the increase of the number of shortcuts can even promote consensus situations. Furthermore, both dynamics coincide for small disorder of the network, but differ for larger disorder. Also we observe that the number of initiators decreases the value of the winning fraction in all types of dynamics and attenuates the local maximum that appears in the small-world region.
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Salameh, Lynne. "Towards faster web page loads over multiple network paths". Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10046643/.
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The rising popularity of mobile devices as the main way people access the web has fuelled a corresponding need for faster web downloads on these devices. Emerging web protocols like HTTP/2 and QUIC employ several features that minimise page load times, but fail to take advantage of the availability of at least two interfaces on today's mobile devices. On the other hand, this spread of devices with access to multiple paths has prompted the design of Multipath TCP, a transport protocol that pools bandwidth across these paths. Although MPTCP was originally evaluated for bandwidth limited bulk transfers, in this work, we determine whether using MPTCP can reduce web page load times, which are often latency bound. To investigate the behaviour of web browsing over MPTCP, we instrumented the Chrome web browser's retrieval of 300 popular web sites in sufficient detail, and computed their dependency graph structure. Furthermore, we implemented PCP, an emulation framework that uses these dependency graphs to ask "what-if" questions about the interactions between a wide range of web site designs, varied network conditions, and different web and transport protocols. Using PCP, we first confirm previous results with respect to the improvements HTTP/2 offers over HTTP/1.1. One obstacle, though, is that many web sites have been sharded to improve performance with HTTP/1.1, spreading their content across multiple subdomains. We therefore examine whether the advice to unshard these domains is beneficial. We find that unsharding is generally advantageous, but is not consistently so. Finally, we examine the behaviour of HTTP/2 over MPTCP. We find that MPTCP can improve web page load times under some regimes; in other cases, using regular TCP on the "best" path is more advantageous. We present enhancements to multipath web browsing that allow it to perform as well as or better than regular TCP on the best path.
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Denazis, S. G. "Queueing network models with blocking and multiple job classes". Thesis, University of Bradford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520630.
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Mattingley-Scott, Mark Alistair. "A code division multiple spread spectrum local area network". Thesis, Durham University, 1989. http://etheses.dur.ac.uk/1451/.
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Welton, Thomas. "Imaging markers of brain network disruption in multiple sclerosis". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43634/.
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Cognitive impairment and fatigue are prevalent and impactful symptoms of multiple sclerosis (MS). Effective markers are required by clinical studies to accurately test the efficacy of treatments for these symptoms. Graph analysis of brain networks based on magnetic resonance imaging (MRI) data can feasibly provide useful candidate markers of cognitive impairment and fatigability in MS which may be more objective, reliable and specific than existing markers. My original contribution to knowledge is therefore an exposition of the following hypothesis: “summary graph-theoretic descriptors of brain network organisation are good candidate markers of cognition or fatigue in MS”. To achieve this, network metrics were assessed based on three main criteria: reliability (“are the measurements the same across time and settings?”), validity (“do they measure what they are supposed to measure?”) and responsiveness (“are they altered when a change in cognitive state is induced?”). The applicability of the graph-theoretic approach was first established with a spatial meta-analysis of tract integrity and its relevance to cognition and disability. Reliability over time in healthy subjects was assessed by systematic review and reliability between different scanners and between MS and control groups was assessed in two longitudinal datasets by measuring intra-class correlation (ICC) of graph metrics. The validity criterion was assessed in an analysis of covariance and linear regression of cognitive and fatigue measures with brain network metrics in people with MS. Finally, an exploration of network dynamics during a sustained attention task with a sliding-window approach was performed to test the immediate responsiveness of the measures to alterations in cognitive state. Spatial meta-analysis of white matter tract degradation was performed using the Signed Differential Mapping method. Statistical maps were gathered from the original authors of studies which performed voxelwise correlations between fractional anisotropy (a measure of white matter integrity based on diffusion tensor imaging data) and measures of either cognitive impairment or physical disability. The combined sample included 495 people with MS and 253 controls from 12 studies. MS diagnosis was significantly associated with widespread lower tract fractional anisotropy. Distributions of voxels with significantly lower fractional anisotropy in relation to cognition and physical disability were only minimally overlapping. The number of and effect sizes for significant clusters in the cognition comparison were greater than those for the physical disability comparison, suggesting a greater relevance of cerebral white matter damage to cognition. The main results remained significant when using a stringent p-value threshold of 0.00001 to control for false positives. The next analysis was a systematic review of the reproducibility of graph metrics over time in healthy people. Online databases were searched for articles reporting ICCs for graph metrics based on imaging data and information was recorded on the sample size, acquisition method, inter-scan interval and reported ICCs. Twenty-six articles were included, with a combined sample size of 676. Overall, reproducibility over time was rated as “good”, but heterogeneity of methods precluded in-depth quantitative analysis. A qualitative synthesis of results highlighted the main methodologic factors affecting reproducibility, which included: ICC type, retest interval, fibre tracking algorithm, graph metric type, image processing strategy, region of interest size, graph threshold and acquisition method. Reliability of brain network metrics between scanners was tested using a travelling-subjects dataset in which 5 subjects each underwent a resting-state functional MRI scan at 10 sites. Graph metrics were calculated for each scan and then tested for ICC across sites. Reproducibility was “poor” for most metrics (characteristic path length ICC=0.23, global efficiency ICC=0.18, modularity ICC=0.24) and “fair” for two (clustering coefficient ICC=0.43, small-worldness ICC=0.42). There was limited evidence that some subjects tended to produce less reliable results and that magnets with higher field strengths did not produce more reliable results. The main implication is that multi-site studies using graph analysis of brain MRI data should investigate inter-site reproducibility beforehand. To investigate the validity of graph metrics as markers of cognitive impairment and fatigue, MRI and neurocognitive data were first gathered from 37 people with MS and 23 matched controls. The sample was characterised in detail and comprised a range of cognitive abilities. Data quality was investigated and the small-world structure of the data was confirmed by comparison to random and lattice graphs. Analysis of covariance controlling for age, sex and education showed significant group differences for all but one graph metric. Linear regression models predicted the main measures of cognitive impairment in the MS group, but not in the control group. Measures of fatigue were not well-explained by graph metrics. The direction of the relationships indicated that greater levels of cognitive impairment were related to increased network clustering and modularity, longer average path lengths, lower small-worldness, lower levels of education, old age and sleep disturbance. Finally, responsiveness of graph metrics was investigated in an analysis of functional network dynamics during performance of a sustained attention task. A “sliding-window” approach was taken, in which network metrics were calculated for 84 100-second windows at increments along the fMRI timeseries. Reaction times in the task showed a learning effect for both groups, but were consistently slower for the MS group. Plots of graph metrics over time showed differing responses to the task and to the transition between task and rest periods between groups. The small-worldness and clustering coefficient metrics were correlated with reaction times for both MS (small-worldness: r=0.623, < 0.001; clustering coefficient: r=0.554, p= < 0.001) and control (small-worldness: r=0.586, < 0.001; clustering coefficient: r=0.627, p= < 0.001) groups, but the characteristic path length metric was not (MS: r=-0.154, p=0.313; control: r=0.343, p=0.021). Disconnection of cortical areas by degradation of white matter is a viable explanation for cognitive symptoms in MS. There is some evidence that increased network segregation and decreased network integration may explain cognitive symptomatology. Graph theoretic summary brain network metrics do have potential for use as complimentary information to existing markers of cognitive impairment in clinical studies.
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Pablo, Rodriguez Juan Manuel. "Multiple Target Detection and Tracking in aMultiple Camera Network". Thesis, KTH, Kommunikationsnät, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175787.
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Given synchronized video sequences from a number of cameras withoverlapping fields of view, the detection and tracking of a priori unknownnumber of individuals entering a determined area is considered, showingthat a generative model can accurately follow the individuals and handleeffectively such problems as occlusions in each view independently. Theaim of this thesis is to implement the exchange of information betweenthe cameras where the detection and tracking processes take place. Theinputs are obtained from synchronized videos and the frames are takenindividually to treat them as independent images. The proposed algo-rithm was implemented in MATLAB and results obtained on a personalcomputer are presented. The results show that the algorithm achievesgood tracking accuracy, has relatively low computational complexity, andat the same time it allows to observe the communication requirementsbetween the cameras and the processing node.
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Vörös, András. "The emergence of multiple status systems in adolescent communities : a multiplex network theory of group formation". Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:9590194f-84e9-4548-b1fe-cf2f64ffc329.
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How do informal groups emerge in adolescent communities? What distinguishes a group from just a set of students? Who will end up together in a group and who will be left out? Why are there more groups in some classrooms and fewer in others? What determines whether these groups overlap in their members or they are completely segregated, perhaps antagonistic? While a huge body of research in sociology and social psychology focuses on these questions, an integrated approach that is able to answer all of them is yet to be developed. Without realizing that these five issues are interrelated, we cannot hope to understand how groups influence individuals and how they shape our communities. This thesis proposes an integrative theory of informal group formation in communities. Based on the tradition of Social Network Analysis, it develops a framework in which interpersonal relations and reputations are formed through a process called informal status production. Groups emerge from this micro-process by the alignment of positive relations and agreement in peer-perceptions between actors. The main micro-mechanisms predicted by the theory are tested on a unique longitudinal network dataset from school classrooms. To this end, a new empirical procedure was developed, by which a few aggregated networks can be constructed from tens of relational items. This allows the analysis of rich network data with several relational dimensions. The empirical studies of multiplex network dynamics confirm that there are strong interdependencies between friendships and perceptions. Students who agree about their peers tend to become friends, but more so when they hold a minority opinion in the class. This contributes to group formation. Friends also influence each other's perceptions, but we manage to show that the presence of groups around them interferes with this process by moderating the influence of individual peers.
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Clark, R. J. (Russell J. ). "Solutions for ubiquitous information services : multiple protocols and scalable servers". Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/8489.
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Veisllari, Raimena. "Employing Ethernet Multiple Spanning Tree Protocol in an OpMiGua network". Thesis, Norwegian University of Science and Technology, Department of Telematics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10913.
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Hybrid optical packet/circuit switched networking architectures are increasingly becoming an interesting research field. They integrate and combine the high resource utilization of statistically multiplexed packet switched networks with the low processing requirements and guaranteed quality of service provided by circuit switched networks. The aim of this thesis is to integrate the OpMiGua hybrid optical network with Ethernet. Specifically, the work is focused on the compatibility of the Ethernets loop-free topology protocols with the redundant multiple traffic service paths of OpMiGua. We analyse the problems and limitations imposed on the network architecture and propose our topology solution called the SM chain-connectivity. The analysis and the proposed schemes are verified based on results obtained from simulations. Furthermore, we design an integrated logical OpMiGua node that relies on an Ethernet switch instead of the Optical Packet Switch for the Statistically Multiplexed traffic. To date, to our knowledge there are no studies analysing the compatibility of Ethernet and its protection mechanisms in a hybrid optical network. This is the first work addressing the use of Ethernet in OpMiGua.
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Walma, Mathys. "Multiple access schemes for the Microwave Light Organized Network (MILTON)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ52395.pdf.
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Sethuruman, Vijayashankar. "A hybrid technique for tracking network structured multiple deformable objects". Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12153/.
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In this thesis, a novel hybrid approach for tracking variable numbers of network structured deformable objects is presented. The hybrid technique developed is a combination of the Network Snakes parametric active contours technique, and the Reversible Jump Markov Chain Monte Carlo (RJMCMC)-based particle filter approach. Additionally, a novel method for (semi-)automatic initialization of the network snakes is implemented. The proposed technique is applied to the real biological problem of tissue-level segmentation, and automatic tracking, of a network of cells in confocal images showing the roots of the model plant Arabidopsis thaliana. The Network Snake component is used to model the structure of cells in Arabidopsis roots, which are clustered together and delineated by shared object boundaries forming a network topology.The RJMCMC tracker is allowed to track the network node points over image sequences, and these tracked nodes are then used to control and reparameterise the topology of the network snakes at each time step. This is followed by energy minimization of the network snakes which refines the tracked nodes and cell boundaries to settle at the energy minimum. Thus the component techniques complement each other in the hybrid approach. A novel method of evaluating such network-structured multi-target tracking is also presented in this thesis, and is used to evaluate the developed tracking framework for accuracy and robustness using several real and synthetic time-varying and depth varying(z-stack) image sequences of growing Arabidopsis roots.
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Kane, Andrew. "An instruction systolic array architecture for multiple neural network types". Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/16031.
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Modern electronic systems, especially sensor and imaging systems, are beginning to incorporate their own neural network subsystems. In order for these neural systems to learn in real-time they must be implemented using VLSI technology, with as much of the learning processes incorporated on-chip as is possible. The majority of current VLSI implementations literally implement a series of neural processing cells, which can be connected together in an arbitrary fashion. Many do not perform the entire neural learning process on-chip, instead relying on other external systems to carry out part of the computation requirements of the algorithm. The work presented here utilises two dimensional instruction systolic arrays in an attempt to define a general neural architecture which is closer to the biological basis of neural networks - it is the synapses themselves, rather than the neurons, that have dedicated processing units. A unified architecture is described which can be programmed at the microcode level in order to facilitate the processing of multiple neural network types. An essential part of neural network processing is the neuron activation function, which can range from a sequential algorithm to a discrete mathematical expression. The architecture presented can easily carry out the sequential functions, and introduces a fast method of mathematical approximation for the more complex functions. This can be evaluated on-chip, thus implementing the entire neural process within a single system. VHDL circuit descriptions for the chip have been generated, and the systolic processing algorithms and associated microcode instruction set for three different neural paradigms have been designed. A software simulator of the architecture has been written, giving results for several common applications in the field.
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Wang, Dong. "Multiple description video coding for robust transmission over unreliable network". Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427880.
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Wang, Yi 1970. "Modeling and solving single and multiple facility network restoration problems". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9944.
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Henkle, Thomas Grove III. "Performance characteristics of a multiple use Ku-band satellite network". Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44646.
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Construction of a Ku-band earth station was completed in August 1989 at the teleport in the
Corporate Research Center of Virginia Polytechnic Institute and State University. At that time
specific applications for the terminal were being determined. Several satellite networks which can
use the Ku-band earth station are explored in this thesis. System level designs are presented for
each network. The anticipated performance of the network during clear sky conditions and during
periods of rain fade conditions are calculated. To aid in these calculations the software package
LAMP was developed.
detailed system design of a VSAT network is given in later chapters. The development of
VSAT networks considers multiple access and data traffic control protocols. VSAT network
performance under various traffic conditions also is determined.
Master of Science
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Li, Mengzhen. "Integration of Node Embeddings for Multiple Versions of A Network". Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1595435155975104.
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Walma, Mathys Carleton University Dissertation Engineering Systems and Computer. "Multiple access schemes for the microwave light organized network (MILTON)". Ottawa, 2000.
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Wu, Victor Kai Yuen. "OFDM-based cooperative communications in a single path relay network and a multiple path relay network". Thesis, Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11092006-152421/.
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Yang, Kent, i Cecelia Wong. "THE FUTURE IN NETWORKING TELEMETRY SYSTEMS". International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/608858.
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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, NevadaWith the ever increasing need for faster data rates and the emergence of faster network interfaces such as Fiber Distributed Data Interface (FDDI), the task of adding new network interfaces to a telemetry system and supporting existing ones is becoming increasingly more complex. This complexity can be eliminated if the data acquisition hardware and software allows new network interfaces to be easily integrated into a telemetry system. It is the purpose of this paper to address the issues involved when dealing with multiple, heterogeneous, networking environments in telemetry systems. The paper will show how the use of flexible telemetry hardware and software will simplify the integration of new networks into an existing system, and how this flexibility can allow data acquisition applications to take advantage of a heterogeneous network.
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Conte, Roberto. "Satellite Rural Telephone Network Design: A Methodology for Performance Optimization". Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/29262.
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Rural telephony has historically been a recurring subject of concern for most large developing countries. It is generally considered that rural telephone users do not generate the same level of telephone traffic and, thus, revenue as urban users, lowering the incentives to invest in rural telecommunications. The financial implications of wiring a vast area for low telephone traffic causes most telephone service providers to ignore or delay offering telephone service to those regions. Still, it is known that telecommunications are essential to the economic development of a region, and that traffic increases rapidly as soon as the service is available.
A satellite-based telephone network can provide efficient long distance telephone service to remote rural communities at a lower cost than land-based wired networks in most cases. Mobile satellite systems already provide this service, but are limited in capacity and charge high per- minute fees for the satellite link. Small earth stations and GEO satellites can provide this service more efficiently and at lower cost.
A methodology to optimize the network performance has been developed. A set of economic models to evaluate different combinations of network topologies and multiple access techniques have been implemented, and a technical-economic assessment has been performed for the different technologies under different traffic scenarios. Traffic intensity, network size and per-minute user costs have been optimized to achieve the network's economic break-even point under different conditions and constraints. The general behavior of fixed-assignment Single Channel per Carrier SCPC), fixed-assignment Multiple Channel per Carrier (MCPC) and demand-assignment SCPC star networks, as well as demand-assignment SCPC mesh networks has been analyzed. Important parameters have been identified in order to improve the process of effective and cost-efficient satellite rural telephone network design.Ph. D.
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Peters, Gavin M. "Time Division Duplex (TDD) Multi-User Multiple-Input, Multiple-Output (MU-MIMO) Mobile Ad-Hoc Network(MANET)". University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563525886227608.
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Pearce, Richard Sargon. "Some aspects of a code division multiple access local area network". Thesis, Durham University, 1987. http://etheses.dur.ac.uk/6810/.
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Zhu, Cheng. "Resource Management Scheme and Network Selection Strategy for Integrated Multiple Traffic Heterogeneous Systems". University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1265988792.
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Fang, Yechang. "Realization of Differentiated Quality of Service for Wideband Code Division Multiple Access Core Network". FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/244.
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The development of 3G (the 3rd generation telecommunication) value-added services brings higher requirements of Quality of Service (QoS). Wideband Code Division Multiple Access (WCDMA) is one of three 3G standards, and enhancement of QoS for WCDMA Core Network (CN) becomes more and more important for users and carriers. The dissertation focuses on enhancement of QoS for WCDMA CN. The purpose is to realize the DiffServ (Differentiated Services) model of QoS for WCDMA CN. Based on the parallelism characteristic of Network Processors (NPs), the NP programming model is classified as Pool of Threads (POTs) and Hyper Task Chaining (HTC). In this study, an integrated programming model that combines both of the two models was designed. This model has highly efficient and flexible features, and also solves the problems of sharing conflicts and packet ordering. We used this model as the programming model to realize DiffServ QoS for WCDMA CN. The realization mechanism of the DiffServ model mainly consists of buffer management, packet scheduling and packet classification algorithms based on NPs. First, we proposed an adaptive buffer management algorithm called Packet Adaptive Fair Dropping (PAFD), which takes into consideration of both fairness and throughput, and has smooth service curves. Then, an improved packet scheduling algorithm called Priority-based Weighted Fair Queuing (PWFQ) was introduced to ensure the fairness of packet scheduling and reduce queue time of data packets. At the same time, the delay and jitter are also maintained in a small range. Thirdly, a multi-dimensional packet classification algorithm called Classification Based on Network Processors (CBNPs) was designed. It effectively reduces the memory access and storage space, and provides less time and space complexity. Lastly, an integrated hardware and software system of the DiffServ model of QoS for WCDMA CN was proposed. It was implemented on the NP IXP2400. According to the corresponding experiment results, the proposed system significantly enhanced QoS for WCDMA CN. It extensively improves consistent response time, display distortion and sound image synchronization, and thus increases network efficiency and saves network resource.
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Rabbat, Michael Gabriel. "Multiple-source network tomography". Thesis, 2003. http://hdl.handle.net/1911/17639.
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Assessing and predicting internal network performance is of fundamental importance in problems ranging from routing optimization to anomaly detection. The problem of estimating internal network structure and link-level performance from end-to-end measurements is called network tomography. This thesis investigates the general network tomography problem involving multiple sources and receivers, building on existing single source techniques. Using multiple sources potentially provides a more accurate and refined characterization of the internal network. The general network tomography problem is decomposed into a set of smaller components, each involving just two sources and two receivers. A novel measurement procedure is proposed which utilizes a packet arrival order metric to classify two-source, two-receiver topologies according to their associated model-order. Then a decision-theoretic framework is developed, enabling the joint characterization of topology and internal performance. A statistical test is designed which provides a quantification of the tradeoff between network topology complexity and network performance estimation.