Dissertations / Theses on the topic 'Networks and systems'
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Andresen, Christian André. "Properties of fracture networks and other network systems." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-5074.
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Newton, Todd A., Myron L. Moodie, Ryan J. Thibodeaux, and Maria S. Araujo. "Network System Integration: Migrating Legacy Systems into Network-Based Architectures." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604308.
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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, CaliforniaThe direction of future data acquisition systems is rapidly moving toward a network-based architecture. There is a handful of these network-based flight test systems already operating, and the current trend is catching on all over the flight test community. As vendors are churning out a whole new product line for networking capabilities, system engineers are left asking, "What do I do with all of this non-networked, legacy equipment?" Before overhauling an entire test system, one should look for a way to incorporate the legacy system components into the modern network architecture. Finding a way to integrate the two generations of systems can provide substantial savings in both cost and application development time. This paper discusses the advantages of integrating legacy equipment into a network-based architecture with examples from systems where this approach was utilized.
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Wells, Daniel David. "Network management for community networks." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1006587.
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Community networks (in South Africa and Africa) are often serviced by limited bandwidth network backhauls. Relative to the basic needs of the community, this is an expensive ongoing concern. In many cases the Internet connection is shared among multiple sites. Community networks may also have a lack of technical personnel to maintain a network of this nature. Hence, there is a demand for a system which will monitor and manage bandwidth use, as well as network use. The proposed solution for community networks and the focus within this dissertation, is a system of two parts. A Community Access Point (CAP) is located at each site within the community network. This provides the hosts and servers at that site with access to services on the community network and the Internet, it is the site's router. The CAP provides a web based interface (CAPgui) which allows configuration of the device and viewing of simple monitoring statistics. The Access Concentrator (AC) is the default router for the CAPs and the gateway to the Internet. It provides authenticated and encrypted communication between the network sites. The AC performs several monitoring functions, both for the individual sites and for the upstream Internet connection. The AC provides a means for centrally managing and effectively allocating Internet bandwidth by using the web based interface (ACgui). Bandwidth use can be allocated per user, per host and per site. The system is maintainable, extendable and customisable for different network architectures. The system was deployed successfully to two community networks. The Centre of Excellence (CoE) testbed network is a peri-urban network deployment whereas the Siyakhula Living Lab (SLL) network is a rural deployment. The results gathered conclude that the project was successful as the deployed system is more robust and more manageable than the previous systems.
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Yuan, Fenghua. "Lightweight network management design for wireless sensor networks." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/F_Yuan_081307.pdf.
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Sandström, Adam, and Nico Klerks. "Evaluation of 6TiSCH network performance for SDN-enabled IoT networks." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-48819.
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Within the Internet of Things (IoT) a need for new IP-compatible communication technologies has grown stronger during the last few years as the need to connect these IoT networks to the Internet has become increasingly more important. In this report, we evaluate IPv6 over the TSCH mode of IEEE 802.15.4e (6TiSCH) with the purpose of observing how different values for the enhanced beacon (EB) period affect certain network metrics such as delay, energy consumption, join time, and throughput. The EB period is a periodic message used in the Time Slotted Channel hopping (TSCH) protocol used to advertise the network. Our goal is to evaluate the effect of different EB periods on the network and determine if there would be a benefit of integrating SDN to change the EB period dynamically. To fulfill our goal, we will evaluate the effect of the change in EB period on the network metrics. This would be an indication that the 6TiSCH network benefits from an integration with SDN. The reason that we would draw this conclusion is because SDN would be capable of predicting the state of the network and from that update the EB period for the 6TiSCH network. Our results indicate that a lower EB period has a positive effect on join times in the network while a longer EB period has a positive effect on the end-to-end delay. Our results display a promising future for future research on the integration of SDN and 6TiSCH.
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Lissai, Gidon. "Assisted GPS solution in cellular networks /." Online version of thesis, 2007. http://hdl.handle.net/1850/3671.
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Kulkarni, Rohan A. "Coolhunting and Coolfarming : harnessing the power of collaborative innovation networks using social network analysis." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90713.
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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 71-73).
Email, Instant Messaging, Voice Over IP (VOIP) and other means of online communication have become so ubiquitous today that we rarely take a moment to acknowledge how the internet has changed and redefined the ways in which we communicate and collaborate with fellow human beings. The internet has empowered us to collaborate with others in ways that were not possible till just a few years ago. As we communicate and interact with each other and form relationships, we weave intricate Social Networks that can be analyzed and exhibit communication patterns that can be quantified. In this thesis I have applied Social Network Analysis based techniques that constitute Coolhunting (Gloor & Cooper, 2007) to analyze E-Mail and WebEx communications of sales professionals of a large technology company. I have quantified communication patterns and computed metrics of social network prominence such as degree and betweenness centralities using Condor, a Social Network Analysis and Coolhunting software. Several significant correlations between the success of sales professionals and these quantified communication patterns and centrality measures were found. The communication patterns and centralities of the sales professionals exhibited several traits of Collaborative Innovation Networks or COINs (Gloor, 2006). I have assessed the implications of these communication patterns and correlations and applied the concept of Coolfarming (Gloor, 2011 a) to make recommendations to the technology company on how it could leverage the power of these COINs to their advantage. Key Terms: Collaborative Innovation Networks (COINs), Coolhunting, Coolfarming, Social Network Analysis, Condor, E-Mail, WebEx
by Rohan Kulkarni.
S.M. in Engineering and Management
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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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Chung, Haera. "Optimal Network Topologies and Resource Mappings for Heterogeneous Networks-on-Chip." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/997.
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Communication has become a bottleneck for modern microprocessors and multi-core chips because metal wires don't scale. The problem becomes worse as the number of components increases and chips become bigger. Traditional Systems-on-Chips (SoCs) interconnect architectures are based on shared-bus communication, which can carry only one communication transaction at a time. This limits the communication bandwidth and scalability. Networks-on-Chip (NoC) were proposed as a promising solution for designing large and complex SoCs. The NoC paradigm provides better scalability and reusability for future SoCs, however, long-distance multi-hop communication through traditional metal wires suffers from both high latency and power consumption. A radical solution to address this challenge is to add long-range, low power, and high-bandwidth single-hop links between distant cores. The use of optical or on-chip RF wireless links has been explored in this context. However, all previous work has focused on regular mesh-based metal wire fabrics that were expanded with one or two additional link types only for long-distance communication.
In this thesis we address the following main research questions to address the above-mentioned challenges: (1) What library of different link types would represent an optimum in the design space? (2) How would these links be used to design an application-specific NoC architecture? (3) How would applications use the resulting NoC architecture efficiently? We hypothesize that networks with a higher degree of heterogeneity, i.e., three or more link types, will improve the network throughput and consume less energy compared to traditional NoC architectures. In order to verify our hypothesis and to address the research challenges, we design and analyze optimal heterogeneous networks under different realistic traffic models by considering different cost and performance trade-offs in a comprehensive technology-agnostic simulation framework that uses metaheuristic optimization techniques. As opposed to related work, our heterogeneous links can be placed anywhere in the network, which allows to explore the entire search space. The resulting application-specific networks are then analyzed by using complex network techniques, such as community detection and small-worldness, to understand how heterogeneous link types are used to improve the NoCs performance and cost. Next, we use the application-specific networks as a target architecture for other applications. The goal is to evaluate the performance of our new NoCs for applications they have not been designed for by finding optimal resource allocations.
Our results show that there is an optimal number of heterogeneous link types for each set of constraints and that networks with three or more heterogeneous link types provide significantly higher throughput along with lower energy consumption compared to both homogeneous link type and regular 2D mesh networks under three different traffic scenarios. Our evolved networks with three different technology-driven link types, namely metal wires, wireless, and optical links, provide 15% more throughput and fourteen times less energy consumption compared to homogeneous link type network. When ten different abstract link types are used in the design, 12% more throughput and 52% less energy consumption are obtained compared to networks with three different technology-driven link types. This shows that heterogeneous NoC designs based on traditional metal wires, wireless, and optical links, occupy a non-optimal spot in the entire design space. Our results further show that heterogeneous NoCs scale up significantly better in terms of performance and cost compared to mesh networks. We uncovered that network communities evolve robustly and that heterogeneous link types are efficiently establishing inter- and intra-subnet connections depending on their link type properties. We also show that mapping an application on our application-specific NoC architecture provides on average 45% more throughput at 70% less energy consumption compared to regular 2D mesh networks. The NoCs are therefore not only good for the application they were designed for, but for a broad range of other applications as well.
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Cheng, King-yip, and 鄭勁業. "Localization in wireless sensor networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38700189.
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Purdin, Titus Douglas Mahlon. "ENHANCING FILE AVAILABILITY IN DISTRIBUTED SYSTEMS (THE SAGUARO FILE SYSTEM)." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184161.
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This dissertation describes the design and implementation of the file system component of the Saguaro operating system for computers connected by a local-area network. Systems constructed on such an architecture have the potential advantage of increased file availability due to their inherent redundancy. In Saguaro, this advantage is made available through two mechanisms that support semi-automatic file replication and access: reproduction sets and metafiles. A reproduction set is a collection of files that the system attempts to keep identical on a "best effort" basis, relying on the user to handle unusual situations that may arise. A metafile is a special file that contains symbolic path names of other files; when a metafile is opened, the system selects an available constituent file and opens it instead. These mechanisms are especially appropriate for situations that do not require guaranteed consistency or a large number of copies. Other interesting aspects of the Saguaro file system design are also described. The logical file system forms a single tree, yet any file can be placed in any of the physical file systems. This organization allows the creation of a logical association among files that is quite different from their physical association. In addition, the broken path algorithm is described. This algorithm makes it possible to bypass elements in a path name that are on inaccessible physical file systems. Thus, any accessible file can be made available, regardless of the availability of directories in its path. Details are provided on the implementation of the Saguaro file system. The servers of which the system is composed are described individually and a comprehensive operational example is supplied to illustrate their interation. The underlying data structures of the file system are presented. The virtual roots, which contain information used by the broken path algorithm, are the most novel of these. Finally, an implementation of reproduction sets and metafiles for interconnected networks running Berkeley UNIX is described. This implementation demonstrates the broad applicability of these mechanisms. It also provides insight into the way in which mechanisms to facilitate user controlled replication of files can be inexpensively added to existing file systems. Performance measurements for this implementation are also presented.
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Ang, Wee Horng. "Scale-free information systems networks." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34554.
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Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2006.Includes bibliographical references (leaves 77-79).
Many real, complex networks have been shown to be scale-free. Scale-free in networks mean that their degree distribution is independent of the network size, have short path lengths and are highly clustered. We identify the qualities of scale-free networks, and discuss the mathematical derivations and numerically simulated outcomes of various deterministic scale-free models. Information Systems networks are a set of individual Information Systems that exchange meaningful data among themselves. However, for various reasons, they do not naturally grow in a scale-free manner. In this topic, we will specifically examine a technique proposed by MITRE that allows information to be exchanged in an efficient manner between Information System nodes. With this technique, we will show that a scale-free Information System Network is sound in theory and practice, state the characteristics of such networks and demonstrate how such a system can be constructed.
by Wee Hong Ang.
S.M.
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Lundy, G. M. "Systems of communicating machines : a model for communication protocols." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/8210.
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Wang, Xiaoyuan. "Network Selection and Rate Allocation in Heterogeneous Wireless Networks and Systems." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258729392.
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Zeigler, Bernard P. "Contrasting emergence: In systems of systems and in social networks." SAGE PUBLICATIONS INC, 2017. http://hdl.handle.net/10150/621270.
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This article considers emergence in the context of systems of systems, examining the earlier proposed tri-layered architecture in some depth. In contrast with healthcare reform, a social media phenomenon, the emergence of topics in the Twitter user community, is shown not to satisfy a critical condition of the architecture. Nevertheless, detection of topic emergence is shown to offer insights into the design of Emergence Behavior Observers.
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Krehling, Daniel E. "Implementing remote image capture/control in a wireless Sensor network utilizing the IEEE 802.15.4 standard." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FKrehling.pdf.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Gibson, John ; Singh, Gurminder. "September 2009." Description based on title screen as viewed on 5 November 2009. Author(s) subject terms: IEEE 802.15.4, wireless sensor network, remote imaging, wireless. Includes bibliographical references (p. 79-81). Also available in print.
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Wang, Bo. "Analysis and implementation of time-delay systems and networked control systems." Thesis, University of South Wales, 2008. https://pure.southwales.ac.uk/en/studentthesis/analysis-and-implementation-of-timedelay-systems-and-networked-control-systems(f54e4378-db9b-443d-b505-88b4af5bb72a).html.
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Systems with delays frequently appear in engineering. The presence of delays makes system analysis and control design much more complicated. Networked control systems where the delays are often random are typical cases of such systems. For one particular category of time-delays systems, integral processes with dead time (IPDTs), the control limits that a PI controller can achieve are discussed in this thesis. These limits include the region of the control parameters to guarantee the system stability, the control parameters to achieve the given gain and/or phase margins (GPMs), the constraint on achievable gain and phase margins, the performance of set point tracking and disturbance rejection. Three types of PI controllers, namely typical PI controller, single tuning-parameter PI controller and PI controller under two-degree-of-freedom (2-DOF) structure, are studied. In control schemes of the modified Smith predictor (MSP) where the controller usually includes a distributed delay, the system implementation is not trivial because of the inherent hidden unstable poles. This thesis provides an estimation of the minimal number of implementation steps for the distributed delay in linear control laws. This is obtained by solving an inequality with respect to the number of implementation steps. A coarse estimation is given as the initial value to solve the inequality using bisection algorithms. A minimization process as well as some other techniques are also introduced to further improve the estimation. In networked control systems, the network-transmission delay and data dropout are combinedly represented by a network-induced delay. By designing a data pre processing mechanism, the network-induced delay can be assigned. Such delay as signment is applied to networked predictive control schemes, which alleviates systemstability limits on the network-induced delay. Two stability criteria are given for the closed-loop system with random network-induced delay, and a resulting implementation algorithm is also provided. The control and implementation of a magnetic levitation system over the network is studied in this thesis. Firstly, a test-rig which is suitable to implement control over a network is set up. Feedback linearization and direct local linearization methods for the nonlinear MagLev system are presented. In order to improve the control performance, a networked predictive method is employed, where the system model is identified in real-time. Local control and networked control are implemented on this test-rig, including networked predictive control. Model predictive control demonstrates a clear performance advantage over the networked control strategies which does not incorporate compensation for the network-induced delay. In order to quickly implement networked control systems (NCSs) by simulation or practical application, a MATLAB/Simulink based NCS toolbox is developed. This toolbox incorporates basic parts of a general NCS, that is, network simulation, network interface, plant interface and typical control schemes. With the NCS toolbox, users can focus on the study of new control schemes.
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Tran, Huy T. "A complex networks approach to designing resilient system-of-systems." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54384.
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This thesis develops a methodology for designing resilient system-of-systems (SoS) networks. This methodology includes a capability-based resilience assessment framework, used to quantify SoS resilience. A complex networks approach is used to generate potential SoS network designs, focusing on scale-free and random network topologies, degree-based and random rewiring adaptation, and targeted and random node removal threats. Statistical design methods, specifically response surface methodology, are used to evaluate SoS networks and provide an understanding of the advantages and disadvantages of potential designs. Linear regression is used to model a continuous representation of the network design space, and determine optimally resilient networks for particular threat types.
The methodology is applied to an information exchange (IE) network model (i.e., a message passing network model) and military command and control (C2) model. Results show that optimally resilient IE network topologies are random for networks with adaptation, regardless of the threat type. However, the optimally resilient adaptation method sharply transitions from being fully random to fully degree-based as threat randomness increases. These findings suggest that intermediately defined networks should not be considered when designing for resilience. Cost-benefit analysis of C2 networks suggests that resilient C2 networks are more cost-effective than robust ones, as long as the cost of rewiring network links is less than three-fourths the cost of creating new links. This result identifies a threshold for which a resilient network design approach is more cost-effective than a robust one.This thesis develops a methodology for designing resilient system-of-systems (SoS) networks. This methodology includes a capability-based resilience assessment framework, used to quantify SoS resilience. A complex networks approach is used to generate potential SoS network designs, focusing on scale-free and random network topologies, degree-based and random rewiring adaptation, and targeted and random node removal threats. Statistical design methods, specifically response surface methodology, are used to evaluate SoS networks and provide an understanding of the advantages and disadvantages of potential designs. Linear regression is used to model a continuous representation of the network design space, and determine optimally resilient networks for particular threat types.
The methodology is applied to an information exchange (IE) network model (i.e., a message passing network model) and military command and control (C2) model. Results show that optimally resilient IE network topologies are random for networks with adaptation, regardless of the threat type. However, the optimally resilient adaptation method sharply transitions from being fully random to fully degree-based as threat randomness increases. These findings suggest that intermediately defined networks should not be considered when designing for resilience. Cost-benefit analysis of C2 networks suggests that resilient C2 networks are more cost-effective than robust ones, as long as the cost of rewiring network links is less than three-fourths the cost of creating new links. This result identifies a threshold for which a resilient network design approach is more cost-effective than a robust one.
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Gabrys, Bogdan. "Neural network based decision support : modelling and simulation of water distribution networks." Thesis, Nottingham Trent University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387534.
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Berzin, Oleg Daryoush Afshin Samimi. "Mobility management architecture and modeling for label switched networks (mobility label based network) a thesis /." Philadelphia, Pa. : Drexel University, 2010. http://hdl.handle.net/1860/3217.
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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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Lakshmanan, Sriram. "Cooperative communication in wireless networks: algorithms, protocols and systems." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42702.
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Current wireless network solutions are based on a link abstraction where a
single co-channel transmitter transmits in any time duration. This model severely
limits the performance that can be obtained from the network. Being inherently an
extension of a wired network model, this model is also incapable of handling the
unique challenges that arise in a wireless medium. The prevailing theme of this
research is to explore wireless link abstractions that incorporate the broadcast and
space-time varying nature of the wireless channel. Recently, a new paradigm for
wireless networks which uses the idea of 'cooperative transmissions' (CT) has garnered
significant attention. Unlike current approaches where a single transmitter transmits
at a time in any channel, with CT, multiple transmitters transmit concurrently after
appropriately encoding their transmissions. While the physical layer mechanisms for
CT have been well studied, the higher layer applicability of CT has been relatively
unexplored. In this work, we show that when wireless links use CT, several network
performance metrics such as aggregate throughput, security and spatial reuse can
be improved significantly compared to the current state of the art. In this context,
our first contribution is Aegis, a framework for securing wireless networks against
eavesdropping which uses CT with intelligent scheduling and coding in Wireless Local
Area networks. The second contribution is Symbiotic Coding, an approach to encode
information such that successful reception is possible even upon collisions. The third
contribution is Proteus, a routing protocol that improves aggregate throughput in
multi-hop networks by leveraging CT to adapt the rate and range of links in a flow.
Finally, we also explore the practical aspects of realizing CT using real systems.
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Bagula, Antoine B. "Hybrid Routing in Next Generation IP Networks : QoS Routing Mechanisms and Network Control Strategies." Doctoral thesis, Stockholm : Telecommunication Systems Laboratory, Department of Computer and Software Systems (ECS), Royal Institute of Technology (KTH), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4213.
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Ho, Chi-Jui. "Call admission control in cellular networks." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/15730.
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Liu, Tuo. "Analytical modeling of HSUPA-enabled UMTS networks for capacity planning." Connect to full text, 2008. http://ses.library.usyd.edu.au/handle/2123/4055.
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Thesis (Ph. D.)--University of Sydney, 2009.Title from title screen (viewed February 20, 2009). Includes graphs and tables. Includes list of publications co-authored with others. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Information Technologies, Faculty of Engineering and Information Technologies. Degree awarded 2009; thesis submitted 2008. Includes bibliographical references. Also available in print form.
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Gummadi, Krishna Phani. "Measurement-driven modeling and design of internet-scale systems /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/6964.
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Kiernan, Leo Andrew. "Learning systems for power transmission networks." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267908.
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Olmucci, Poddubnyy Oleksandr. "Graph Neural Networks for Recommender Systems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amslaurea.unibo.it/25033/.
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In recent years, a new type of deep learning models, Graph Neural Networks (GNNs), have demonstrated to be a powerful learning paradigm when applied to problems that can be described via graph data, due to their natural ability to integrate representations across nodes that are connected via some topological structure. One of such domains is Recommendation Systems, the majority of whose data can be naturally represented via graphs. For example, typical item recommendation datasets can be represented via user-item bipartite graphs, social recommendation datasets by social networks, and so on. The successful application of GNNs to the field of recommendation, is demonstrated by the state of the art results achieved on various datasets, making GNNs extremely appealing in this domain, also from a commercial perspective. However, the introduction of graph layers and their associated sampling techniques significantly affects the nature of the calculations that need to be performed on GPUs, the main computational accelerator used nowadays: something that hasn't been investigated so far by any of the architectures in the recommendation literature. This thesis aims to fill this gap by conducting the first systematic empirical investigation of GNN-based architectures for recommender systems, focusing on their multi-GPU scalability and precision speed-up properties, when using different types of hardware.
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Al-Dulaimi, Anwer. "Cognitive radio systems in LTE networks." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/11544.
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The most important fact in the mobile industry at the moment is that demand for wireless services will continue to expand in the coming years. Therefore, it is vital to find more spectrums through cognitive radios for the growing numbers of services and users. However, the spectrum reallocations, enhanced receivers, shared use, or secondary markets-will not likely, by themselves or in combination, meet the real exponential increases in demand for wireless resources. Network operators will also need to re-examine network architecture, and consider integrating the fibre and wireless networks to address this issue. This thesis involves driving fibre deeper into cognitive networks, deploying microcells connected through fibre infrastructure to the backbone LTE networks, and developing the algorithms for diverting calls between the wireless and fibre systems, introducing new coexistence models, and mobility management. This research addresses the network deployment scenarios to a microcell-aided cognitive network, specifically slicing the spectrum spatially and providing reliable coverage at either tier. The goal of this research is to propose new method of decentralized-to-distributed management techniques that overcomes the spectrum unavailability barrier overhead in ongoing and future deployments of multi-tiered cognitive network architectures. Such adjustments will propose new opportunities in cognitive radio-to-fibre systematic investment strategies. Specific contributions include: 1) Identifying the radio access technologies and radio over fibre solution for cognitive network infrastructure to increase the uplink capacity analysis in two-tier networks. 2) Coexistence of macro and microcells are studied to propose a roadmap for optimising the deployment of cognitive microcells inside LTE macrocells in the case of considering radio over fibre access systems. 3) New method for roaming mobiles moving between microcells and macrocell coverage areas is proposed for managing spectrum handover, operator database, authentication and accounting by introducing the channel assigning agent entity. The ultimate goal is to reduce unnecessary channel adaptations.
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Westby, Karl David. "Systems analysis of freight transportation networks /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10126.
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Kuzyk, Mark. "Multimode Optomechanical Systems and Phononic Networks." Thesis, University of Oregon, 2019. http://hdl.handle.net/1794/24186.
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An optomechanical system consists of an optical cavity mode coupled
to a mode of a mechanical oscillator. Depending on the configuration of the
system, the optomechanical interaction can be used to drive or cool the
mechanical mode, coherently swap the optical and mechanical states, or create
entanglement.
A multimode optomechanical system consists of many optical (mechanical) modes
coupled to a mechanical (optical) mode. With the tools of the optomechanical
interaction, multimode optomechanical systems provide a rich platform to study
new physics and technologies. A central challenge in optomechanical systems
is to mitigate the effects of the thermal environment, which remains
significant even at cryogenic temperatures, for mechanical oscillators
typically used in optomechanical systems. The central theme of this thesis is
to study how the properties of multimode optomechanical systems can be used
for such mitigation of thermal noise.
The most straightforward extension of an optomechanical system to a multimode
system is to have a single optical mode couple to two mechanical modes, or a
single mechanical mode couple to two optical modes. In this thesis, we study
both types of multimode system. In each case, we study the formation of a
dark mode, an eigenstate of the three-mode system that is of particular
interest. When the system is in a dark state, the two modes of similar
character (optical or mechanical) interact with each other through the mode of
dissimilar character, but due to interference, the interaction becomes
decoupled from the properties of the dissimilar mode.
Another interesting application of the three-mode system is two-mode optical
entanglement, generated through mechanical motion. Such entanglement tends to
be sensitive to thermal noise. We propose a new method for generating
two-mode optical entanglement in the three-mode system that is robust against
the thermal environment of the mechanical mode.
Finally, we propose a novel, scalable architecture for a quantum computer.
The architecture makes use of the concepts developed earlier in the thesis,
and applies them to a system that on the surface looks quite different from
the standard optomechanical system, but is formally equivalent.
This dissertation includes previously published and unpublished coauthored
material.
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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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Fridborn, Fredrik. "Reading Barcodes with Neural Networks." Thesis, Linköpings universitet, Datorseende, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-143477.
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Barcodes are ubiquituous in modern society and they have had industrial application for decades. However, for noisy images modern methods can underperform. Poor lighting conditions, occlusions and low resolution can be problematic in decoding. This thesis aims to solve this problem by using neural networks, which have enjoyed great success in many computer vision competitions the last years. We investigate how three different networks perform on data sets with noisy images. The first network is a single classifier, the second network is an ensemble classifier and the third is based on a pre-trained feature extractor. For comparison, we also test two baseline methods that are used in industry today. We generate training data using software and modify it to ensure proper generalization. Testing data is created by photographing barcodes in different settings, creating six image classes - normal, dark, white, rotated, occluded and wrinkled. The proposed single classifier and ensemble classifier outperform the baseline as well as the pre-trained feature extractor by a large margin. The thesis work was performed at SICK IVP, a machine vision company in Linköping in 2017.
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Fu, Haohuan. "Efficient multimedia data transmission over heterogeneous networks /." access full-text access abstract and table of contents, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?mphil-cs-b19887218a.pdf.
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Thesis (M. Phil.)--City University of Hong Kong, 2005."Submitted to Department of Computer Science in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references (leaves 105-108).
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Adas, Abdelnaser M. "Supporting multimedia traffic in broadband networks." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/14849.
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Ho, Joseph S. M. "Mobility management for personal communications networks." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/14882.
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Irfan, Nazish. "Design and Optimization of RFID Systems." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31380.
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This thesis deals with the design of cost-effective large-scale RFID networks from both software and hardware aspects. To start with, different computer-aided tools were developed to maximize performance. The first set of algorithms focused on the elimination of redundant readers to minimize the cost and interference in large-scale RFID networks. For validation, uniform reader coverage was assumed, as widely used in most available publications. Then, both omni-directional and directional commercial reader antenna data were included for more reliability.
Besides redundancy, an efficient physical placement of readers was also investigated by considering both uniform and random distribution over space. For this purpose, genetic-based algorithms have been proposed to increase reader coverage using commercial reader antenna beams.
Energy consumption is also a critical design parameter for dense RFID networks. Therefore, a third set of algorithms was developed to efficiently minimize the energy consumption of large-scale RFID systems. Note that all above optimization techniques were achieved without compromising the whole RFID network performance.
To further optimize cost and performance of large-scale RFID networks, a hardware approach through reader antenna design has been considered. In fact, since different RFID frequency bands have been assigned worldwide, large-scale RFID networks implemented in industrial parks, airports, or international trade zones, may deal with imported merchandise using tags operating at different frequencies. Therefore, in-house single and dual-band microstrip and CPW fed monopole antennas were successfully designed and tested to improve system adaptability to various RFID standards. These antennas were designed using both electromagnetic commercial simulators (HFSS) and in-house FDTD-based techniques.
Finally, to further extend dense RFID network capabilities, one may implement a substantial number of readers and antennas with small reading ranges to cover a large monitoring area, or use high gain phased array antenna system for an extended reading range of an RFID reader for a smaller number of total reader deployments. Therefore, a phased antenna array system can be an efficient alternative for dense RFID networks. Thus, a switched beam network to control the phase of the radiating elements of the array has been successfully designed and tested.
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Yu, Fan. "Self organization in medium access control for wireless ad hoc and sensor networks." Diss., Connect to online resource - MSU authorized users, 2008.
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Gavini, Sireesh. "Detecting packet-dropping faults in mobile ad-hoc networks." Online access for everyone, 2004. http://www.dissertations.wsu.edu/Thesis/Fall2004/s%5Fgavini%5F121404.pdf.
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Li, Guoqing. "Resource allocation in OFDMA networks /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/6136.
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Cox, Criston W. "Optimizing bandwidth of tactical communications systems." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FCox.pdf.
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Thesis (M.S. in Systems Technology (Joint Command, Control, Communications, Computers and Intelligence (JC4I))--Naval Postgraduate School, June 2005.Thesis Advisor(s): William Kemple, John Osmundson. Includes bibliographical references (p. 59-60). Also available online.
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Yasarer, Hakan. "Decision making in engineering prediction systems." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/16231.
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Doctor of PhilosophyDepartment of Civil Engineering
Yacoub M. Najjar
Access to databases after the digital revolutions has become easier because large databases are progressively available. Knowledge discovery in these databases via intelligent data analysis technology is a relatively young and interdisciplinary field. In engineering applications, there is a demand for turning low-level data-based knowledge into a high-level type knowledge via the use of various data analysis methods. The main reason for this demand is that collecting and analyzing databases can be expensive and time consuming. In cases where experimental or empirical data are already available, prediction models can be used to characterize the desired engineering phenomena and/or eliminate unnecessary future experiments and their associated costs. Phenomena characterization, based on available databases, has been utilized via Artificial Neural Networks (ANNs) for more than two decades. However, there is a need to introduce new paradigms to improve the reliability of the available ANN models and optimize their predictions through a hybrid decision system. In this study, a new set of ANN modeling approaches/paradigms along with a new method to tackle partially missing data (Query method) are introduced for this purpose. The potential use of these methods via a hybrid decision making system is examined by utilizing seven available databases which are obtained from civil engineering applications. Overall, the new proposed approaches have shown notable prediction accuracy improvements on the seven databases in terms of quantified statistical accuracy measures. The proposed new methods are capable in effectively characterizing the general behavior of a specific engineering/scientific phenomenon and can be collectively used to optimize predictions with a reasonable degree of accuracy. The utilization of the proposed hybrid decision making system (HDMS) via an Excel-based environment can easily be utilized by the end user, to any available data-rich database, without the need for any excessive type of training.
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Loo, Siew Lan. "Neural networks for financial forecasting." Thesis, University College London (University of London), 1994. http://discovery.ucl.ac.uk/1317942/.
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Neural networks demonstrate great potential for discovering non-linear relationships in time-series and extrapolating from them. Results of forecasting using financial data are particularly good [LapFar87, Schöne90, ChaMeh92]. In contrast, traditional statistical methods are restrictive as they try to express these non-linear relationships as linear models. This thesis investigates the use of the Backpropagation neural model for time-series forecasting. In general, neural forecasting research [Hinton87] can be approached in three ways: research into, the weight space, into the physical representation of inputs, and into the learning algorithms. A new method to enhance input representations to a neural network, referred to as model sNx, has been developed. It has been studied alongside a traditional method in model N. The two methods reduce the unprocessed network inputs to a value between 0 and 1. Unlike the method in model N, the variants of model sNx, sN1 and sN2, accentuate the contracted input value by different magnitudes. This different approach to data reduction exploits the characteristics of neural extrapolation to achieve better forecasts. The feasibility of the principle of model sNx has been shown in forecasting the direction of the FFSE-100 Index. The experimental strategy involved optimisation procedures using one data set and the application of the optimal network from each model to make forecasts on different data sets with similar and dissimilar patterns to the first. A Neural Forecasting System (NFS) has been developed as a vehicle for the research. The NFS offers historical and live simulations, and supports: a data alignment facility for standardising data files with non-uniform sampling times and volumes, and merging them into a spreadsheet; a parameter specification table for specifications of neural and system control parameter values; a pattern specification language for specification of input pattern formation using one or more time-series, and loading to a configured network; a snapshot facility for re-construction of a partially trained network to continue or extend a training session, or re-construction of a trained network to forecast for live tests; and a log facility for recording experimental results. Using the NFS, specific pattern features selected from major market trends have been investigated [Pring8O]: triple-top ('three peaks'), double-top ('two peaks'), narrow band ('modulating'), bull ('rising') and recovery ('U-turn'). Initially, the triple-top pattern was used in the N model to select between the logarithmic or linear data form for presenting raw input data. The selected linear method was then used in models sN1, sN2 and N for network optimisations. Experiments undertaken used networks of permutations of sizes of input nodes (I), hidden nodes (H), and tolerance value. Selections were made for: the best method, by value, direction, or value and direction, for measuring prediction accuracy; the best configuration function, H - I 4), with 4) equal to 0.9, 2 or 3; and the better of sN1 and sN2. The evaluation parameters were, among others, the prediction accuracy (%), the weighted return (%), the Relative Threshold Prediction Index (RTPI) indicator, the forecast error margins. The RTPI was developed to filter out networks forecasting above a minimum prediction accuracy with a credit in the weighted return (%). Two optimal networks, one representing model sNx and one N were selected and then tested on the double-top, narrow band, bull and recovery patterns. This thesis made the following research conthbutions. • A new method in model sNx capable of more consistent and accurate predictions. • The new RTPI neural forecasting indicator. • A method to forecast during the consolidation ('non-diversifying') trend which most traditional methods are not good at. • A set of improvements for more effective neural forecasting systems.
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Zhang, Jun. "Power control in wireless ad hoc networks /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CSED%202007%20ZHANG.
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Orfanidis, Charalampos. "Robustness in low power wide area networks." Licentiate thesis, Uppsala universitet, Avdelningen för datorteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-351481.
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During the past few years we have witnessed an emergence of Wide Area Networks in the Internet of Things area. There are several new technologies like LoRa, Wi-SUN, Sigfox, that offer long range communication and low power for low-bitrate applications. These new technologies enable new application scenarios, such as smart cities, smart agriculture, and many more. However, when these networks co-exist in the same frequency band, they may cause problems to each other since they are heterogeneous and independent. Therefore it is very likely to have frame collisions between the different networks. In this thesis we first explore how tolerant these networks are to Cross Technology Interference (CTI). CTI can be described as the interference from heterogeneous wireless technologies that share the same frequency band and is able to affect the robustness and reliability of the network. In particular, we select two of them, LoRa and Wi-SUN and carry out a series of experiments with real hardware using several configurations. In this way, we quantify the tolerance of cross technology interference of each network against the other as well as which configuration settings are important. The next thing we explored is how well channel sensing mechanisms can detect the other network technologies and how they can be improved. For exploring these aspects, we used the default Clear Channel Assessment (CCA) mechanism of Wi-SUN against LoRa interference and we evaluated how accurate it is. We also improved this mechanism in order to have higher accuracy detection against LoRa interference. Finally, we propose an architecture for WSNs which will enable flexible reconfiguration of the nodes. The idea is based on Software Defined Network (SDN) principles and could help on our case by reconfiguring a node in order to mitigate the cross-technology interference from other networks.
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Facchetti, Giuseppe. "Computational approaches to complex biological networks." Doctoral thesis, SISSA, 2013. http://hdl.handle.net/20.500.11767/4822.
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The need of understanding and modeling the biological networks is one of the raisons d'être and of the driving forces behind the emergence of Systems Biology. Because of its holistic approach and because of the widely different level of complexity of the networks, different mathematical methods have been developed during the years. Some of these computational methods are used in this thesis in order to investigate various properties of different biological systems. The first part deals with the prediction of the perturbation of cellular metabolism induced by drugs. Using Flux Balance Analysis to describe the reconstructed genome-wide metabolic networks, we consider the problem of identifying the most selective drug synergisms for given therapeutic targets. The second part of this thesis considers gene regulatory and large social networks as signed graphs (activation/deactivation or friendship/hostility are rephrased as positive/negative coupling between spins). Using the analogy with an Ising spin glass an analysis of the energy landscape and of the content of “disorder” 'is carried out. Finally, the last part concerns the study of the spatial heterogeneity of the signaling pathway of rod photoreceptors. The electrophysiological data produced by our collaborators in the Neurobiology laboratory have been analyzed with various dynamical systems giving an insight into the process of ageing of photoreceptors and into the role diffusion in the pathway.
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Christmann, Hans Claus. "Self-configuring ad-hoc networks for unmanned aerial systems." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22626.
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Shalf, John Marshall. "Advanced System-Scale and Chip-Scale Interconnection Networks for Ultrascale Systems." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/36134.
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The path towards realizing next-generation petascale and exascale computing is increasingly dependent on building supercomputers with unprecedented numbers of processors. Given the rise of multicore processors, the number of network endpoints both on-chip and off-chip is growing exponentially, with systems in 2018 anticipated to contain thousands of processing elements on-chip and billions of processing elements system-wide. To prevent the interconnect from dominating the overall cost of future systems, there is a critical need for scalable interconnects that capture the communication requirements of target ultrascale applications. It is therefore essential to understand high-end application communication characteristics across a broad spectrum of computational methods, and utilize that insight to tailor interconnect designs to the specific requirements of the
underlying codes. This work makes several unique contributions towards attaining that goal. First, the communication traces for a number of high-end application communication requirements, whose computational methods include: finite-difference, lattice-Boltzmann, particle-in-cell, sparse linear algebra, particle mesh ewald, and FFT-based solvers.
This thesis presents an introduction to the fit-tree approach for designing network infrastructure that is tailored to application requirements. A fit-tree minimizes the component count of an interconnect without impacting application performance compared to a fully connected network. The last section introduces a methodology for reconfigurable networks to implement fit-tree solutions called Hybrid Flexibly Assignable Switch Topology (HFAST). HFAST uses both passive (circuit) and active (packet) commodity switch components in a unique way to dynamically reconfigure interconnect wiring to suit the topological requirements of scientific applications. Overall the exploration points to several promising directions for practically addressing both the on-chip and off-chip interconnect requirements of future ultrascale systems.Master of Science
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Rogers, Paul Edward. "On robustness in high load mobile ad hoc networks." Diss., Online access via UMI:, 2005.
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Moore, Michael S., Evan T. Grim, Ganesh U. Kamat, and Myron L. Moodie. "MANAGEMENT OF NETWORK-BASED FLIGHT TEST SYSTEMS." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604409.
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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaNetwork-based instrumentation systems are rapidly replacing traditional fixed serial interconnected instrumentation in both commercial and military flight test environments. Modern network-based flight test systems are composed of large numbers of devices including high-speed network switches, data acquisition devices, recorders, telemetry interfaces, and wireless network transceivers, all of which must be managed in a coordinated fashion. Management of the network system includes configuring, controlling, and monitoring the health and status of the various devices. Configuration by hand is not a realistic option, so algorithms for automatic management must be implemented to make these systems economical and practical. This paper describes the issues that must be addressed for managing network-based flight test systems and describes a network management approach that was developed and employed to manage a large-scale network-based flight test system.