Dissertations / Theses on the topic 'Network designs'
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Kwong, Kae Hsaing. "Passive optical network architecture designs." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415311.
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Rodan, Ali. "Architectural designs of Echo State Network." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3610/.
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It investigates systematically the reservoir construction of Echo State Network (ESN). This thesis proposes two very simple deterministic ESN organisation (Simple Cycle reservoir (SCR)) and Cycle Reservoir with Jumps (CRJ). Simple Cycle reservoir (SCR) is sufficient to obtain performances comparable to those of the classical ESN. While Cycle Reservoir with Jumps (CRJ) significantly outperform the those of the classical ESN. This thesis also studies and discusses three reservoir characterisations - short-term memory capacity (MC), eigen-spectrum of the reservoir weight matrix and Lyapunov Exponent with their relation to the ESN performance. It also designs and utilises an ensemble of ESNs with diverse reservoirs whose collective readout is obtained through Negative Correlation Learning (NCL) of ensemble of Multi-Layer Perceptrons (MLP), where each individual MPL realises the readout from a single ESN. Finally, this thesis investigates the relation between two quantitative measures characterising short term memory in input driven dynamical systems, namely the short term memory capacity (MC), and the Fisher memory curve (FMC).
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Abdalla, Hassan Z. "Performance Analysis of Multicomputer Interconnection Network Designs." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/101364.
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In this thesis, the design and performance issues of multicomputer interconnection networks are addressed. Analytic models are used to evaluate the performance of large scale multicomputer networks. Performance is measured as the average end-to-end delay between communicating nodes. The models consider the communication processing queueing delays experienced by packets at each node as well as delays associated with transmission of packets. A comparison study of message switching and cut-through switching is presented. It is shown, conforming to previous studies, that a network has superior performance when cut-through switching is used. Cut-through switching is most advantageous when the network load is low and degenerates to message switching performance under heavy network loads.
The network model is used to develop a "Network Analyzer", an interactive program that allows analysis of different network designs and workloads. Torus and spanning bus hypercube networks are then analyzed by the program to study the effect of various network parameters, traffic patterns, and switching techniques on network delay performance. The Network Analyzer is relatively easy to learn and use, and once learned, it is easy to change network parameters to perform a trade-off study of design alternatives. The program can also be used to quickly generate listings and graphics to illustrate the results of the analysis. The program proved to be an efficient design tool.
Hypercube topologies are the most popular for large scale parallel computers, particularly for computationally intensive applications. The torus and spanning bus hypercubes are implemented in our program and analyzed in detail. Results show that network topology has a mixed impact on system performance. Networks built of standard modules of spanning bus hypercubes are harder to expand, compared to a torus network, but they have lower connection cost per node. Communication delays are generally higher for spanning bus networks except at very low traffic loads.M.S.
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Pokhilko, Victoria V. "Statistical Designs for Network A/B Testing." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6101.
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A/B testing refers to the statistical procedure of experimental design and analysis to compare two treatments, A and B, applied to different testing subjects. It is widely used by technology companies such as Facebook, LinkedIn, and Netflix, to compare different algorithms, web-designs, and other online products and services. The subjects participating in these online A/B testing experiments are users who are connected in different scales of social networks. Two connected subjects are similar in terms of their social behaviors, education and financial background, and other demographic aspects. Hence, it is only natural to assume that their reactions to online products and services are related to their network adjacency. In this research, we propose to use the conditional autoregressive model (CAR) to present the network structure and include the network effects in the estimation and inference of the treatment effect. The following statistical designs are presented: D-optimal design for network A/B testing, a re-randomization experimental design approach for network A/B testing and covariate-assisted Bayesian sequential design for network A/B testing. The effectiveness of the proposed methods are shown through numerical results with synthetic networks and real social networks.
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Low, Douglas Wai Kok. "Network processor memory hierarchy designs for IP packet classification /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/6973.
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Zhang, Yixuan. "High-Performance Crossbar Designs for Network-on-Chips (NoCs)." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1282056856.
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Osman, Rasha Izzeldin Mohammed. "Performance Modelling of Database Designs using a Queueing Networks Approach. An investigation in the performance modelling and evaluation of detailed database designs using queueing network models." Doctoral thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4870.
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Databases form the common component of many software systems, including mission
critical transaction processing systems and multi-tier Internet applications. There is a
large body of research in the performance of database management system components,
while studies of overall database system performance have been limited. Moreover,
performance models specifically targeted at the database design have not been
extensively studied.
This thesis attempts to address this concern by proposing a performance evaluation
method for database designs based on queueing network models. The method is targeted
at designs of large databases in which I/O is the dominant cost factor. The database
design queueing network performance model is suitable in providing what if
comparisons of database designs before database system implementation.
A formal specification that captures the essential database design features while keeping
the performance model sufficiently simple is presented. Furthermore, the simplicity of
the modelling algorithms permits the direct mapping between database design entities
and queueing network models. This affords for a more applicable performance model
that provides relevant feedback to database designers and can be straightforwardly
integrated into early database design development phases. The accuracy of the
modelling technique is validated by modelling an open source implementation of the
TPC-C benchmark. The contribution of this thesis is considered to be significant in that the majority of
performance evaluation models for database systems target capacity planning or overall
system properties, with limited work in detailed database transaction processing and
behaviour. In addition, this work is deemed to be an improvement over previous
methodologies in that the transaction is modelled at a finer granularity, and that the
database design queueing network model provides for the explicit representation of
active database rules and referential integrity constraints.Iqra Foundation
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Le, Tung Thanh. "Optimizing Network-on-Chip Designs for Heterogeneous Many-Core Architectures." Thesis, University of Louisiana at Lafayette, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10981900.
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On-chip Interconnection Networks are shifting from multicore to manycore systems and are tending to be heterogeneous with the integrated modules from different vendors of various sizes and shapes. Each module has different properties such as routers, link-width. From a system designer's perspective, making layouts of metal-wired links among interconnection modules for communication will be impractical as it increases the design cost in terms of the communication complexity and power leakage on these links. We can replace all links with wireless or optical links for high-performance, reducing latency. However, it comes with a high-cost. Therefore, we formulate the optimization model to minimize the cost (communication links between subnets) and maximize their data flows in the network-on-chip.
Since the optimization model using the optimizers such as CPLEX and Gurobi to achieve the best possible solutions, the solution time to a large set of given problems is not acceptable. Hence, we present a mincostflow-based heuristic algorithm (LINCA) that minimizes the quantification of hybrid routers corresponding to the application-specific traffic for manycore systems. LINCA guarantees the performance of hybrid networks on chip. Its results are validated against the manycore system architecture. Our evaluation shows that LINCA can significantly reduce the cost of using hybrid routers (communication links) in the manycore systems. It reduces cost by 84 percent on average across a variety of applications, compared with all of hybrid routers being deployed in the network without using the optimization model. However, we observed that the solution time of LINCA is increased exponentially for large scale networks. We then proposed an efficient predictive framework for optimized reconfiguring on-chip interconnection network.
The predictive model is built based on the optimization model and learning-based algorithms. As we wish to reduce the communication complexity of the interconnection links in the entire on-chip network, our objective is to minimize those links corresponding to the application-specific traffic demands. Thereby, the overall power dissipation can be mitigated. We believe that our approach will be an essential step when scaling out.
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Qiao, Wei. "Integrated control of wind farms, facts devices and the power network using neural networks and adaptive critic designs." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29716.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.Committee Chair: Ronald G. Harley; Committee Member: David G. Taylor; Committee Member: Deepakraj M. Divan; Committee Member: Ganesh Kumar Venayagamoorthy; Committee Member: Thomas G. Habetler. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Gadhavi, Divyaraj, and Trushar Pansuriya. "2.45 GHz Antenna Designs with Impedance Matching Network : NIBE AB, Markaryd, Sweden." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-37758.
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This master thesis is a part of digitization project at NIBE AB, Markaryd, Sweden.Nowadays, the demand for digitization is increasing. One of the main goals ofdigitization is to build smart houses and industries to offer better lifestyles.NIBE is a company which produces heat pumps, water heaters, district waterheaters, digital stoves and etc. NIBE AB is planning to launch their new products witha communication module which helps users to control NIBE AB’s products remotelythrough their personal devices such as mobile phones, remote control devices and etc.The main objective of this thesis project is to improve these communicationmodules by improving their antenna with better design or replacing them with otherkinds of antennas for efficient communication and also accordingly design impedancematching networks for the system.This work presents the integrated results of an antenna for NIBE AB, tuned tocover 2.45 GHz ISM band which will implemented on a communication module. Wedesigned and simulated four types of different Printed Circuit Board (PCB) antennasand we got the better simulation results of Gain, Reflection Coefficient, VSWR andBand Width from these designs.Also, we used different types of substrates in the simulation to get goodresults and design the impedance matching networks accordingly. If we compare theresults with the current monopole antenna and its parameters, we have goodcharacteristic results in most of the aspects.
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Ghorbani, a. "Cross polar cancellation in satellite microwave systems : New practical designs and applications of propagation theory." Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376711.
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Camacho, Villanueva Jesús. "High Performance and Power Efficient On-Chip Network Designs through Multiple Injection Ports." Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/18235.
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Las redes dentro de un chip se están convirtiendo en el elemento principal de los sistemas multiprocesador. A medida que aumenta la escala de integración, más elementos de cómputo (procesadores) se incluyen en el mismo chip. Estos componentes se interconectan con una red dentro del chip que debe ofrecer latencias de transmisión ultra bajas (orden de nanosegundos) y anchos de banda elevados. El diseño, pues, de una red eficiente dentro del chip juega un papel fundamental.
En la presente tesis se analizan diferentes alternativas de diseño de las redes en el chip. En particular, se hace uso de la posibilidad de utilizar diferentes puertos de inyección desde los procesadores con el fin de obtener diferentes mejoras.
En primer lugar, las prestaciones aumentan al tener procesadores con distintas alternativas de inyección de tráfico. En segundo lugar, además aumenta la tolerancia a fallos frente a defectos de fabricación (mas importantes conforme avanza la tecnología). Y en tercer lugar, permite una política de apagado de componentes más agresiva que nos permita un ahorro significativo de energía.
Hemos evaluado diferentes topologías derivadas del mecanismo de inyección en términos de prestaciones, coste de implementación, y ahorro de consumo. Además, hemos desarrollado simuladores específicos para las distintas técnicas utilizadas.
Cada topología diseñada supone una mejora respecto a la anterior, y por supuesto, teniendo en cuenta las topologías existentes. En resumen, nuestro esfuerzo se centra en conseguir un excelente compromiso entre prestaciones, consumo y tolerancia a fallos dentro de una red en chip.
Para la primera propuesta (topología NR-Mesh), se alcanzan mejoras en prestaciones de un 7\% y hasta de un 75\% en reducción de consumo de media, comparado con la malla 2D o malla de 2 dimensiones. Para la siguiente propuesta, la malla concentrada paralela (PC-Mesh), el beneficio en prestaciones que se obtiene es de hasta un 20\%, así cómo de un 60\% en reducción deCamacho Villanueva, J. (2012). High Performance and Power Efficient On-Chip Network Designs through Multiple Injection Ports [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18235
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Wang, Mei. "Algorithms and architecture designs for network addressing and routing scalability and router performance /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Akbar, Ghanadian Sara. "A Framework Based on Social Network Analysis (SNA) to Evaluate Facilities and Alternative Network Designs for Closed Loop Supply Chains." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1596583638602018.
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Hernández, Luz Carles. "Addressing Manufacturing Challenges in NoC-based ULSI Designs." Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/16694.
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Hernández Luz, C. (2012). Addressing Manufacturing Challenges in NoC-based ULSI Designs [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16694Palancia
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Serumaga-Zake, John Mugambwa. "Experimental models for network mesh topologies with designs that enhance survivability / J.M. Serumaga-Zake." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1375.
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Sudev, Bharath. "Improving packet predictability of scalable network-on-chip designs without priority pre-emptive arbitration." Thesis, University of York, 2015. http://etheses.whiterose.ac.uk/12088/.
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The quest for improving processing power and efficiency is spawning research into many-core systems with hundreds or thousands of cores. With communication being forecast as the foremost performance bottleneck, Network-on-Chips are the favoured communication infrastructure in the context mainly due to reasons like scalability and power efficiency. However, contention between non-preemptive NoC packets can result in variation in packet latencies thus potentially limiting the overall utilisation of the many-core system. Typical latency predictability enhancement techniques like Virtual Channels or Time Division Multiplexing are usually hardware expensive or non-scalable or both. This research explores the use of dynamic and scalable techniques in Network-on-Chip routers to improve packet predictability by countering Head-of-line blocking (blocked low priority packet blocking a high priority packet) and tailbacking (low priority packet utilising the link that is required by a high priority packet) of non-preemptive packets. The Priority forwarding and tunnelling technique introduced is designed to detect Head-of-line blocking situations so that its internal arbitration parameters can be altered (by forwarding packet parameters down the line) to resolve such issues. The Selective packet splitting technique presented allows resolution of tailbacking by emulating the effect of preemption of packets (by splitting packets) by using a low overhead alternative that manipulates packets. Finally, the thesis presents an architecture that allows the routers to have a notion of timeliness in data packets thus enabling packet arbitration based on application-supplied priority and timeliness thus improving the quality of service given to lower priority packets. Furthermore, the techniques presented in the thesis do not require additional hardware with the increase in size of the NoC. This enables the techniques to be scalable, as the size of the NoC or the number of packet priorities the NoC has to handle does not affect the functionality and operation of the techniques.
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Alimadadi, Mehdi. "Recycling clock network energy in high-performance digital designs using on-chip DC-DC converters." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1447.
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Power consumption of CMOS digital logic designs has increased rapidly for the last several years. It has become an important issue, not only in battery-powered applications, but also in high-performance digital designs because of packaging and cooling requirements. At multi-GHz clock rates in use today, charging and discharging CMOS gates and wires, especially in clocks with their relatively large capacitances, leads to significant power consumption. Recovering and recycling the stored charge or energy about to be lost when these nodes are discharged to ground is a potentially good strategy that must be explored for use in future energy-efficient design methodologies.
This dissertation investigates a number of novel clock energy recycling techniques to improve the overall power dissipation of high-performance logic circuits. If efficient recycling energy of the clock network can be demonstrated, it might be used in many high-performance chip designs, to lower power and save energy.
A number of chip prototypes were designed and constructed to demonstrate that this energy can be successfully recycled or recovered in different ways:
• Recycling clock network energy by supplying a secondary DC-DC power converter: the output of this power converter can be used to supply another region of the chip, thereby avoiding the need to draw additional energy from the primary supply. One test chip demonstrates energy in the final clock load can be recycled, while another demonstrates that clock distribution energy can be recycled.
• Recovering clock network energy and returning it back to the power grid: each clock cycle, a portion of the energy just drawn from the supply is transferred back at the end of the cycle, effectively reducing the power consumption of the clock network.
The recycling methods described in this thesis are able to preserve the more ideal square clock shape which has been a limitation of previous work in this area. Overall, the results provided in this thesis demonstrate that energy recycling is very promising and must be pursued in a number of other areas of the chip in order to obtain an energy-efficient design.
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Xu, Mengting. "Exploring the influence of privacy control designs on users' interpersonal trust in online social network environments." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44679.
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Over more than a decade, IS research has examined the role of trust in the context of technology adoptions, such as website acceptance (Gefen et al. 2003), successful
online interactions (Coppola et al. 2004) and recommendation agent usage (Wang and Benbasat 2005). The primary antecedent of trust in this line of research is trustee’s trustworthiness. However, Dashiti et al. (2011) articulated the effect of trust- received (trustor’s felt trust from trustee) on trust-given (trustor’s trust in trustee) and consequently the trusting behaviors in the e-government context. This study aims to investigate the context of online social networks (OSNs) and to test whether trust-received plays a similar role in forming the interpersonal trust among Facebook user’s interactions. Based on this trust reciprocity theory, this study aims to find out (i) whether users are more willing to trust others and share their personal information with them when individuals experienced trust-received and (ii) what factors, especially what IT features, influence trust-received in personal networking context. We hypothesize that information sensitivity and audience limitation are two main influencing factors over users’ trust-received on Facebook. We analyzed our hypotheses using an online
scenario-based survey, and based on our findings we proposed a new IT artifact in the follow-up study to explore more trust-received influencing factors. We found that audience limitation (an IT artifact) has the most significant impact over trust-received and that reciprocity of trust does exist on Facebook. We also concluded that the mentioning of a virtual function in which the re-share could be switched on or off has an effect over trust-received under certain circumstances. Thus we concluded that IT artifacts can help build or maintain online users relationships and that trust can form from a reciprocity pattern.
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Petrovic, Vladimir [Verfasser], and Rolf Dr Ing [Akademischer Betreuer] Kraemer. "Design methodology for highly reliable digital ASIC designs applied to network-centric system middleware switch processor / Vladimir Petrovic. Betreuer: Rolf Dr.-Ing Kraemer." Cottbus : Universitätsbibliothek der BTU Cottbus, 2014. http://d-nb.info/104733657X/34.
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Knutsson, Magnus, and Linus Lindahl. "A COMPARATIVE STUDY OF FFN AND CNN WITHIN IMAGE RECOGNITION : The effects of training and accuracy of different artificial neural network designs." Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-17214.
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Image recognition and -classification is becoming more important as the need to be able to process large amounts of images is becoming more common. The aim of this thesis is to compare two types of artificial neural networks, FeedForward Network and Convolutional Neural Network, to see how these compare when performing the task of image recognition. Six models of each type of neural network was created that differed in terms of width, depth and which activation function they used in order to learn. This enabled the experiment to also see if these parameters had any effect on the rate which a network learn and how the network design affected the validation accuracy of the models. The models were implemented using the API Keras, and trained and tested using the dataset CIFAR-10. The results showed that within the scope of this experiment the CNN models were always preferable as they achieved a statistically higher validation accuracy compared to their FFN counterparts.
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Wiedemeier, Paul Douglas. "Transport, network, and data link layer protocol designs to improve geo-stationary Earth orbit satellite data set transmission performance." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4190.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 25, 2006) Vita. Includes bibliographical references.
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Cracraft, Michael Andrew. "Mobile array designs with ANSERLIN antennas and efficient, wide-band PEEC models for interconnect and power distribution network analysis." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/mcthesis20070623_09007dcc80374999.pdf.
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Thesis (Ph. D.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 134-136).
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Dong, Junwei. "Microwave Lens Designs: Optimization, Fast Simulation Algorithms, and 360-Degree Scanning Techniques." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/29081.
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Microwave lenses support low-phase error, wideband, wide-angle scanning, and true-time delay (TTD) beam forming. They provide ideal performance for applications such as satellites, remote-piloted vehicles, collision-avoidance radars and ultra-wideband communications systems. The emerging printed lenses in recent years have facilitated the advancement of designing high performance but low-profile, light-weight, and small-size beam-forming networks (BFNs). The microwave lens adopts a few beam ports to illuminate the prescribed receiving ports that feed energy into radiating antennas. Multi-beam patterns can be achieved by exciting multiple beam ports at a time. The design process starts with path-length equations from a limited number of beam-port foci assumptions. This constraint does not take into account the amplitude information; however, it allows an initial lens geometry to be solved. The resulted scanning angle of microwave lens is limited by the beam port contour, as such ± 90 degrees.
In this dissertation, three contributions are made from the aspects of minimized phase errors, accurate and efficient simulation algorithms, and 360-degree scanning range extension. First, a minimum-phase-error, non-focal lens design method is proposed. It does not require a specific number of foci along the beam contour; however, minimum phase errors for all beam ports are able to be achieved. The proposed method takes into account flexible prescribed geometrical design parameters, and adopts numerical optimization algorithms to perform phase error minimization. Numerical results compared with the published tri-focal and quadru-focal lenses demonstrate the merits of the proposed method. Second, an accurate and fast simulation method for the microwave lens has been developed to predict the phase, amplitude, array factor, and power efficiency performance. The proposed method is compared to both full-wave simulation and measurement. Comparable results have been achieved. Third, a novel method for a 360-degree scanning microwave lens is proposed. This concept uses the beam ports and the receive ports in an interleaving sequence such that adjacent ports alternate beam and receive functions. The result is a lens that produces scanned beams on opposite sides of the structure resulting in a 360-degree scanning range. The structure can use multiple opposing facets or continuous circular-port and radiating-element contours. To prove the concept, a four-facet microstrip lens has been designed, simulated, fabricated, and tested. The comparison between full-wave simulation and measurement has demonstrated good agreement.Ph. D.
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Gnawali, Krishna Prasad. "EMERGING MEMORY-BASED DESIGNS AND RESILIENCY TO RADIATION EFFECTS IN ICS." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/dissertations/1863.
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The performance of a modern computing system is improving with technology scaling due to advancements in the modern semiconductor industry. However, the power efficiency along with reliability does not scale linearly with performance efficiency. High leakage and standby power in sub 100 nm technology are critical challenges faced by circuit designers. Recent developments in device physics have shown that emerging non-volatile memories are very effective in reducing power dissipation because they eliminate stand by power and exhibit almost zero leakage powerThis dissertation studies the use of emerging non-volatile memory devices in designing circuit architecture for improving power dissipation and the performance of the computing system. More specically, it proposes a novel spintronic Ternary Content AddressableMemory (TCAM), a novel memristive TCAM with improved power and performance efficiency. Our experimental evaluation on 45 nm technology for a 256-bit word-size spintronic TCAM at a supply voltage of 1 V with a sense margin of 50 mV show that the delay is lessthan 200 ps and the per-bit search energy is approximately 3 fJ. The proposed spintronic TCAM consumes at least 30% less energy when compared to state-of-the-art TCAM designs. The search delay on a 144-bit proposed memristive TCAM at a supply voltage of 1 V and a sense margin of 140 mV is 175 ps with per bit search energy of 1.2 fJ on a 45 nm technology. It is 1.12 x times faster and dissipates 67% less search energy per bit than the fastest existing 144-bit MTCAM design.Emerging non-volatile memories are well known for their ability to perform fast analog multiplication and addition when they are arranged in crossbar fashion and are especially suited for neural network applications. However, such systems require the on-chip implementation of the backpropagation algorithm to accommodate process variations. This dissertation studies the impact of process variation in training memristive neural network architecture. It proposes a low hardware overhead on-chip implementation of the backpropagation algorithm that utilizes effectively the very dense memristive cross-bar arrayand is resilient to process variations.Another important issue that needs a careful study due to shrinking technology node is the impact of space or terrestrial radiation in Integrated Circuits (ICs) because the probability of a high energy particle causing an error increases with a decrease in thethreshold voltage and the noise margin. Moreover, single-event effects (SEEs) sensitivity depends on the set of input vectors used at the time of testing due to logical masking. This dissertation analyzes the impact of input test set on the cross section of the microprocessorand proposes a mechanism to derive a high-quality input test set using an automatic test pattern generation (ATPG) for radiation testing of microprocessors arithmetic and logical units..
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Warshawsky, David. "A system of systems flexibility framework: A method for evaluating designs that are subjected to disruptions." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54277.
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As systems become more interconnected, the focus of engineering design must shift
to include consideration for systems of systems (SoS) e ects. As the focus shifts from
singular systems to systems of systems, so too must the focus shift from performance
based analysis to an evaluation method that accounts for the tendency of such large
scale systems to far outlive their original operational environments and continually
evolve in order to adapt to the changes. It is nearly impossible to predict the nature
of these changes, therefore the rst focus of this thesis is the measurement of
the
exibility of the SoS and its ability to evolve and adapt. Flexibility is measured
using a combination of network theory and a discrete event simulation, therefore,
the second focus is the development of a simulation environment that can also measure
the system's performance for baseline comparisons. The results indicate that
simulated
exibility is related to the performance and cost of the SoS and is worth
measuring during the design process. The third focus of this thesis is to reduce the
computational costs of SoS design evaluation by developing heuristics for
exibility.
This was done by developing a network model to correspond with the discrete event
simulation and evaluating network properties using graph theory. It was shown that
the network properties can correlate with simulated
exibility. In such cases it was
shown that the heuristics could be used in connection with an evolutionary algorithm
to rapidly search the design space for good solutions. The entire methodology was
demonstrated on a multi-platform maintenance planning problem in connection with
the Navy Hardware Open System Technologies initiative.
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Patterson, Raymond A. "Hybrid Neural networks and network design." Connect to resource, 1995. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1262707683.
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Van, Staden C. J., and Der Westhuizen D. Van. "Learn 2.0 technologies and the continuing professional development of secondary school mathematics teachers." Journal for New Generation Sciences, Vol 11, Issue 2: Central University of Technology, Free State, Bloemfontein, 2013. http://hdl.handle.net/11462/642.
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Published ArticleThe paper reports on a Learn 2.0 technology that was used to support the continuing professional development of mathematics teachers at a secondary school. Design Based Research methods were used within a Multiphase Mixed Methods research framework to create professional development opportunities that were subsequently monitored by Social Network Analysis techniques. We demonstrate that Learn 2.0 technologies can indeed support the continuing professional development of teachers and improve their performance, and also that Social Network Analysis is an effective method to describe, comprehend, clarify and transparently monitor teacher engagement during online professional development activities. We identify 'participation' as a key pre-determinant to success.
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Matos, Débora da Silva Motta. "Exploring hierarchy, adaptability and 3D in NoCs for the next generation of MPSoCs." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/94764.
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A demanda por sistemas com elevado desempenho tem trazido a necessidade de aumentar o número de elementos de processamento, surgindo os chamados Sistemas em Chip Multiprocessados (MPSoCs). Além disso, com a possibilidade de redução da escala tecnológica na era submicrônica, permitindo a integração de vários dispositivos, os chips têm se tornado ainda mais complexos. No entanto, com o aumento no número de elementos de processamento, as interconexões são vistas com o principal gargalo dos sistemas-em-chip. Com isso, uma preocupação na forma como tais elementos se comunicam e estão interconectados tem sido levantada, uma vez que tais características são cruciais nos aspectos de desempenho, energia e potência, principalmente em sistemas embarcados. Essa necessidade permitiu o advento das redes-em-chip (Networks-on-Chip – NoCs) e inúmeros estudos já foram realizados para tais dispositivos. No entanto, devido ao aceleramento tecnológico atual, que traz a necessidade por sistemas ainda mais complexos, que consumam baixa energia e que permitam que as aplicações sejam constantemente atualizadas sem perder as características de desempenho, as arquiteturas de interconexão tradicionais não serão suficientes para satisfazer tais desafios. Outras alternativas de interconexão para MPSoCs precisam ser investigadas e nesse trabalho novas arquiteturas para NoCs com tais requisitos são apresentadas. As soluções propostas exploram hierarquia, adaptabilidade e interconexões em três dimensões. Esse trabalho aborda a necessidade do uso de diferentes estratégias em NoCs a fim de atingir os requisitos de desempenho e baixo consumo de potência dos atuais e futuros MPSoCs. Dessa forma, serão verificadas as diversas arquiteturas de interconexões para sistemas heterogêneos, sua escalabilidade, suas principais características e as vantagens das propostas apresentadas sobre as demais soluções.The demand for systems with high performance has brought the need to increase the number of cores, emerging the called Multi-Processors System-on-Chip (MPSoCs). Also, with the shrinking feature size in deep-submicron era, allowing the integration of several devices, chips have become even more complex. However, with the increase in these elements, interconnections are seen as the main bottleneck in many core systemson- chip. With this, a concern about how these devices communicate and are interconnected has been raised, since these features are crucial for the performance, energy and power consumption aspects, mainly in embedded systems. This need allows the advent of the Networks-on-Chip (NoCs) and countless studies had already been done to analyze such interconnection devices. However, due to the current technological accelerating that brings the need for even more complex systems, consuming lower energy and providing constant application updates without losing performance features, traditional interconnect architectures will not be sufficient to satisfy such challenges. Other interconnecting alternatives for MPSoCs need to be investigated and in this work, novel architectures for NoCs meeting such requirements are presented. The proposed solutions explore hierarchy, adaptability and three dimensional interconnections. This work approaches the requirements in the use of different strategies for NoCs in order to reach the performance requisites and low power consumption of the current and future MPSoCs. Hence, in this approach, several interconnection architectures for heterogeneous systems, their scalability and the main features and advantages of the proposed strategies in comparison with others will be verified.
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Do-Duy, Tan. "Design of network coding functionality for 5G networks." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/665972.
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La codificación de red (NC) ha surgido recientemente como una nueva solución para mejorar el rendimiento de la red en términos de rendimiento y fiabilidad. Sin embargo, la naturaleza multiusuario de NC y su aplicabilidad inherente a la ingeniería de flujo versátil en todas las capas de la pila de protocolos requieren nuevos enfoques de diseño de sistemas inalámbricos. El objetivo de esta tesis es estudiar el diseño de NC como una funcionalidad de red ofrecida a los diseñadores de servicios de comunicación inalámbrica 5G. El diseño facilitaría el control del rendimiento de la red, la confiabilidad y la conectividad a través de redes inalámbricas 5G. Las contribuciones de esta tesis son las siguientes. Primero desarrollamos un diseño de Funcionalidad de codificación de red como una caja de herramientas de dominios de diseño NC y mostramos cómo se puede integrar en las infraestructuras virtualizadas actuales. En segundo lugar, evaluamos el rendimiento de longitud finita de diferentes códigos de red usando matrices aleatorias vs Pascal. Modelamos el proceso de codificación, recodificación y decodificación de diferentes esquemas de codificación en notación de matriz y las correspondientes probabilidades de error. A continuación, proponemos un algoritmo de búsqueda binaria para identificar la velocidad de codificación óptima para algunas tasas de pérdida de paquetes de destino específicas dada una longitud de bloque de codificación predefinida. Nos enfocaremos en los códigos de logro de capacidad y los esquemas de codificación con la programación de escenarios representativos y mostraremos la compensación de la tasa de retardo alcanzable entre los códigos aleatorios y los códigos estructurados con la programación. En la última parte de esta tesis, validamos el diseño de NCF propuesto para un caso de uso completo para mejorar la conectividad de los dispositivos de red móvil ad-hoc (MANET) sobre las redes convergidas de nubes satelitales en aplicaciones de emergencia. La idea clave es que en un escenario de emergencia puede no haber acceso directo a la niebla o la computación en la nube, que luego se proporcionará por satélite y los únicos recursos computacionales locales disponibles son los dispositivos MANET. Para resolver esta situación, definimos un NCF a nivel de paquetes con entradas de objetivos de calidad del servicio de datos, restricciones de computación local y estadísticas por ruta. Las salidas son tasas de codificación centralmente optimizadas que equilibran los recursos computacionales por nodo y la cobertura resultante.Network coding (NC) has recently emerged as a new solution for improving network performance in terms of throughput and reliability. However, the multi-user nature of NC and its inherent applicability to versatile flow engineering across all layers of the protocol stack, call for novel wireless system design approaches. The goal of this thesis is to study the design of NC as a network functionality offered to the 5G wireless communication service designers. The design would facilitate the control of network throughput, reliability, and connectivity over 5G wireless networks. The contributions of this thesis are the following. We first develop a design of Network Coding Functionality as a toolbox of NC design domains and show how it can be integrated in current virtualized infrastructures. Second, we evaluate the finite-length performance of different network codes using random vs Pascal matrices. We model the encoding, re-encoding, and decoding process of different coding schemes in matrix notation and corresponding error probabilities. We then propose a binary searching algorithm to identify optimal coding rate for some specific target packet loss rates given a pre-defined coding block-length. We will focus on capacity-achieving codes and coding schemes with scheduling for representative scenarios and show the achievable rate-delay trade-off between random codes and structured codes with scheduling. In the last part of this thesis, we validate the proposed NCF design for a complete use case to enhance connectivity of Mobile Ad-hoc Network (MANET) devices over converged satellite-cloud networks in emergency applications. The key insight is that in an emergency scenario there may not be direct access to fog or cloud computing, which will then be provided via satellite and the only local computational resources available are the MANET devices. To solve this situation, we define a packet-level NCF with inputs from data service quality targets, local computation constraints and per-path statistics. Outputs are centrally-optimized coding rates balancing per-node computational resources and resulting coverage.
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Zhao, Wenrui. "Routing and Network Design in Delay Tolerant Networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14085.
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Delay tolerant networks (DTNs) are a class of emerging networks that exhibit significantly different characteristics from today's Internet, such as intermittent connectivity, large delay, and high loss rates. DTNs have important applications in disaster relief, military, rural Internet access, environmental sensing and surveillance, interplanetary communication, underwater sensing, and vehicular communication. While not the common case for networking, DTNs represent some of the most critical cases, where the ability to communicate can make a huge difference for human lives.
Supporting effective communication in DTNs, however, is challenging. First, with intermittent connectivity, DTNs are often extremely limited in capacity. Second, given resource limitations and uncertainty in DTNs, it is critical to deliver data efficiently and robustly. The situation is especially acute for multicast which sends data to multiple destinations.
This thesis seeks to address these two issues. To enhance network capacity in DTNs, we propose a message ferrying scheme that exploits the use of special mobile nodes (called message ferries) and controlled device mobility to deliver data. Message ferries are utilized to transport data via mobility between sources and destinations. We develop a foundation for the control of the mobility of message ferries, and nodes if possible, to cooperatively deliver data under a variety of conditions. We also study another approach which deploys new nodes called throwboxes to enhance capacity. Throwboxes are small and inexpensive wireless devices. By relaying data between mobile nodes, throwboxes are able to create data transfer opportunities that otherwise would not exist. We systematically investigate the issues of deployment and routing, and develop algorithms for various deployment and routing approaches. Based on extensive evaluation, we obtain several findings to guide the design and operation of throwbox-augmented DTNs.
To address the issue of efficient and robust data delivery, we focus on DTN multicasting. Given the unique characteristics of DTNs, traditional solutions such as IP multicast can not be simply ported to DTNs. We identify the limitations of IP multicast semantics in DTNs and define new semantic models for DTN multicast. Based on these semantic models, we develop and evaluate several multicast routing algorithms with different routing strategies.
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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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Zhu, Yong. "Routing, Resource Allocation and Network Design for Overlay Networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14017.
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Overlay networks have been the subject of significant research and practical interest recently in addressing the inefficiency and ossification of the current Internet. In this thesis, we cover various aspects of overlay network design, including overlay routing algorithms, overlay network assignment and multihomed overlay networks. We also examine the behavior of overlay networks under a wide range of network settings and identify several key factors that affect the performance of overlay networks. Based on these findings, practical design guidelines are also given. Specifically, this thesis addresses the following problems:
1) Dynamic overlay routing: We perform an extensive simulation study to investigate the performance of available bandwidth-based dynamic overlay routing from three important aspects: efficiency, stability, and safety margin. Based on the findings, we propose a hybrid routing scheme that achieves good performance in all three aspects. We also examine the effects of several factors on overlay routing performance, including network load, traffic variability, link-state staleness, number of overlay hops, measurement errors, and native sharing effects.
2) Virtual network assignment: We investigate the virtual network (VN) assignment problem in the scenario of network virtualization. Specifically, we develop a basic VN assignment scheme without reconfiguration and use it as the building block for all other advanced algorithms. Subdividing heuristics and adaptive optimization strategies are presented to further improve the performance. We also develop a selective VN reconfiguration scheme that prioritizes the reconfiguration for the most critical VNs. 3) Overlay network configuration tool for PlanetLab: We develop NetFinder, an automatic overlay network configuration tool to efficiently allocate PlanetLab resources to individual overlays. NetFinder continuously monitors the resource utilization of PlanetLab and accepts a user-defined overlay topology as input and selects the set of PlanetLab nodes and their interconnection for the user overlay. 4) Multihomed overlay network: We examine the effectiveness of combining multihoming and overlay routing from the perspective of an overlay service provider (OSP). We focus on the corresponding design problem and examine, with realistic network performance and pricing data, whether the OSP can provide a network service that is profitable, better (in terms of round-trip time), and less expensive than the competing native ISPs.
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Morley, George David. "Analysis and design of ring-based transport networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60329.pdf.
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Mukhija, Punit. "A Wireless Call Button Network Design." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/9763.
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Traditional call button networks that control elevator systems utilize a wired connection for communication. The communication cables are run through the elevator shaft from one call button to another and finally to the controller on the roof. Installing this wired link is highly time consuming. In this thesis, we propose the design for a wireless call button network. Two important features of this wireless network design are low cost and low power consumption. Controller Area Network (CAN) is a widely used protocol for wired networks and has been proposed for use in next generation elevator control systems. A modified CAN for wireless (MCANW) protocol has been developed for the wireless call button network. The wireless link will be implemented via the use of data radios. A modified form of traditional Binary Phase Shift Keying (BPSK) modulation scheme for the radios is proposed. The proposed modulation scheme, like differential BPSK, can be detected non-coherently but it offers better performance than differential BPSK. Its implementation includes an innovative tracking algorithm to maintain synchronization at the receiver.Master of Science
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Cui, Nenghui. "Wireless Sensor Networks - Network Coded Cooperative Communication : Design and Implementation." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-188750.
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This thesis is concerned with the design and implementation of a testbed for network coded cooperative communication (NC-CC) in IEEE 802.15.4-based wireless sensor networks (WSNs). The work and test are based on Contiki 2.5 and sensor nodes Zolertia Z1. In the testbed, a new network framework with large extensibility is provided, as well as a basic realization of NC-CC. In our implementation, CC is realized as a Rime primitive in Contiki, while NC is inserted as a new layer between Rime and MAC to perform opportunistic coding. In this way the network stack of Contiki is extended while still keeping the backward compatibility. Because of the lack of multicast in IEEE 802.15.4 protocol and the contradiction of applying continuous overhearing on power-constraint sensor nodes, new mechanisms called pseudo overhearing and pseudo multicast is proposed in our testbed. A configurable test program is also designed for the purpose of evaluation. A combination of two senders, one relay and one destination is used as our network model. Experiments show that all the designed functions work properly. But to be robust, more experiments under different models should be brought in the future. A more detailed report on the experiments can be found in my project-partner Yitian Yan’s thesis.
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Hanselmann, Thomas. "Approximate dynamic programming with adaptive critics and the algebraic perceptron as a fast neural network related to support vector machines." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0005.
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[Truncated abstract. Please see the pdf version for the complete text. Also, formulae and special characters can only be approximated here. Please see the pdf version of this abstract for an accurate reproduction.] This thesis treats two aspects of intelligent control: The first part is about long-term optimization by approximating dynamic programming and in the second part a specific class of a fast neural network, related to support vector machines (SVMs), is considered. The first part relates to approximate dynamic programming, especially in the framework of adaptive critic designs (ACDs). Dynamic programming can be used to find an optimal decision or control policy over a long-term period. However, in practice it is difficult, and often impossible, to calculate a dynamic programming solution, due to the 'curse of dimensionality'. The adaptive critic design framework addresses this issue and tries to find a good solution by approximating the dynamic programming process for a stationary environment. In an adaptive critic design there are three modules, the plant or environment to be controlled, a critic to estimate the long-term cost and an action or controller module to produce the decision or control strategy. Even though there have been many publications on the subject over the past two decades, there are some points that have had less attention. While most of the publications address the training of the critic, one of the points that has not received systematic attention is training of the action module.¹ Normally, training starts with an arbitrary, hopefully stable, decision policy and its long-term cost is then estimated by the critic. Often the critic is a neural network that has to be trained, using a temporal difference and Bellman's principle of optimality. Once the critic network has converged, a policy improvement step is carried out by gradient descent to adjust the parameters of the controller network. Then the critic is retrained again to give the new long-term cost estimate. However, it would be preferable to focus more on extremal policies earlier in the training. Therefore, the Calculus of Variations is investigated to discard the idea of using the Euler equations to train the actor. However, an adaptive critic formulation for a continuous plant with a short-term cost as an integral cost density is made and the chain rule is applied to calculate the total derivative of the short-term cost with respect to the actor weights. This is different from the discrete systems, usually used in adaptive critics, which are used in conjunction with total ordered derivatives. This idea is then extended to second order derivatives such that Newton's method can be applied to speed up convergence. Based on this, an almost concurrent actor and critic training was proposed. The equations are developed for any non-linear system and short-term cost density function and these were tested on a linear quadratic regulator (LQR) setup. With this approach the solution to the actor and critic weights can be achieved in only a few actor-critic training cycles. Some other, more minor issues, in the adaptive critic framework are investigated, such as the influence of the discounting factor in the Bellman equation on total ordered derivatives, the target interpretation in backpropagation through time as moving and fixed targets, the relation between simultaneous recurrent networks and dynamic programming is stated and a reinterpretation of the recurrent generalized multilayer perceptron (GMLP) as a recurrent generalized finite impulse MLP (GFIR-MLP) is made. Another subject in this area that is investigated, is that of a hybrid dynamical system, characterized as a continuous plant and a set of basic feedback controllers, which are used to control the plant by finding a switching sequence to select one basic controller at a time. The special but important case is considered when the plant is linear but with some uncertainty in the state space and in the observation vector, and a quadratic cost function. This is a form of robust control, where a dynamic programming solution has to be calculated. ¹Werbos comments that most treatment of action nets or policies either assume enumerative maximization, which is good only for small problems, except for the games of Backgammon or Go [1], or, gradient-based training. The latter is prone to difficulties with local minima due to the non-convex nature of the cost-to-go function. With incremental methods, such as backpropagation through time, calculus of variations and model-predictive control, the dangers of non-convexity of the cost-to-go function with respect to the control is much less than the with respect to the critic parameters, when the sampling times are small. Therefore, getting the critic right has priority. But with larger sampling times, when the control represents a more complex plan, non-convexity becomes more serious.
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Zang, Joanna Q. "Design of a redundancy protocol /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418080.
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Al-Mousa, Yamin Samir. "MAC/routing design for under water sensor networks /." Online version of thesis, 2007. http://hdl.handle.net/1850/4496.
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Twu, Philip Y. "Control of multi-agent networks: from network design to decentralized coordination." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43713.
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This dissertation presents a suite of design tools for multi-agent systems that address three main areas: network design, decentralized controller generation, and the synthesis of decentralized control strategies by combining individual decentralized controllers. First, a new metric for quantifying heterogeneity in multi-agent systems is presented based on combining different notions of entropy, and is shown to overcome the drawbacks associated with existing diversity metrics in various scientific fields. Moreover, a new method of controlling multi-agent networks through the single-leader network paradigm is presented where by directly exploiting the homogeneity of agent capabilities, a network which is not completely controllable can be driven closer to a desired target configuration than by using traditional control techniques. An algorithm is presented for generating decentralized control laws that allow for agents to best satisfy a desired global objective, while taking into account network topological constraints and limitations on how agents can compute their control signals. Then, a scripting tool is developed to aid in specifying sequences of decentralized controllers to be executed consecutively, while helping ensure that the required network topological requirements needed for each controller to execute properly are maintained throughout mode switches. Finally, the underlying concepts behind the developed tools are showcased in three example applications: distributed merging and spacing for heterogeneous aircraft during terminal approaches, collaborative multi-UAV convoy protection in dynamic environments, and an educational tool used to teach a graduate-level networked controls course at the Georgia Institute of Technology.
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Yang, Zhenyu. "Network Coding in Multihop Wireless Networks: Throughput Analysis and Protocol Design." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-dissertations/222.
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Multi-hop wireless networks have been widely considered as promising approaches to provide more convenient Internet access for their easy deployment, extended coverage, and low deployment cost. However, providing high-speed and reliable services in these networks is challenging due to the unreliable wireless links, broadcast nature of wireless transmissions, and frequent topology changes. On the other hand, network coding (NC) is a technique that could significantly improve the network throughput and the transmission reliability by allowing intermediate nodes to combine received packets. More recently proposed symbol level network coding (SLNC), which combines packets at smaller symbol scale, is a more powerful technique to mitigate the impact of lossy links and packet collisions in wireless networks. NC, especially SLNC, is thus a particular effective approach to providing higher data rate and better transmission reliability for applications such as mobile content distribution in multihop wireless networks. This dissertation focuses on exploiting NC in multihop wireless networks. We studied the unique features of NC and designed a suite of distributed and localized algorithms and protocols for content distribution networks using NC and SLNC. We also carried out a theoretical study on the network capacity and performance bounds achievable by SLNC in mobile wireless networks. We proposed CodeOn and CodePlay for popular content distribution and live multimedia streaming (LMS) in vehicular ad hoc networks (VANETs), respectively, where many important practical factors are taken into consideration, including vehicle distribution, mobility pattern, channel fading and packet collision. Specifically, CodeOn is a novel push based popular content distribution scheme based on SLNC, where contents are actively broadcast to vehicles from road side access points and further distributed among vehicles using a cooperative VANET. In order to fully enjoy the benefits of SLNC, we proposed a suite of techniques to maximize the downloading rate, including a prioritized and localized relay selection mechanism where the selection criteria is based on the usefulness of contents possessed by vehicles, and a lightweight medium access protocol that naturally exploits the abundant concurrent transmission opportunities. CodePlay is designed for LMS applicaitions in VANETs, which could fully take advantage of SLNC through a coordinated local push mechanism. Streaming contents are actively disseminated from dedicated sources to interested vehicles via local coordination of distributively selected relays, each of which will ensure smooth playback for vehicles nearby. CodeOn pursues a single objective of maximizing downloading rate, while CodePlay improves the performance of LMS service in terms of streaming rate, service delivery delay, and bandwidth efficiency simultaneously. CodeOn and CodePlay are among the first works that exploit the features of SLNC to simplify the protocol design whilst achieving better performance. We also developed an analytical framework to compute the expected achievable throughput of mobile content distribution in VANETs using SLNC. We presented a general analytical model for the expected achievable throughput of SLNC in a static wireless network based on flow network theory and queuing theory. Then we further developed the model to derive the expected achievable accumulated throughput of a vehicle driving through the area of interest under a mobility pattern. Our proposed framework captures the effects of multiple practical factors, including vehicle distribution and mobility pattern, channel fading and packet collision, and we characterized the impacts of those factors on the expected achievable throughput. The results from this research are not only of interest from theoretical perspective but also provide insights and guidelines on protocol design in SLNC-based networks.
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alyanbaawi, ashraf. "DESIGN OF EFFICIENT MULTICAST ROUTING PROTOCOLS FOR COMPUTER NETWORKS." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/dissertations/1775.
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Multicasting can be done in two different ways: source based tree approach andshared tree approach. Shared tree approach is preferred over source-based treeapproach because in the later construction of minimum cost tree per source is neededunlike a single shared tree in the former approach. However, in shared tree approach asingle core needs to handle the entire traffic load resulting in degraded multicastperformance. Besides, it also suffers from „single point failure‟. Multicast is acommunication between one or multiple senders and multiple receivers, which used asa way of sending IP datagrams to a group of interested receivers in one transmission.Core-based trees major concerns are core selection and core as single point of failure.The problem of core selection is to choose the best core or cores in the network toimprove the network performance.In this dissertation we propose 1) a multiple core selection approach for core-based tree multicasting, senders can select different cores to have an efficient loadbalanced multicore multicasting. It will overcome any core failure as well. 2) Novel andefficient schemes for load shared multicore multicasting are presented. Multiple coresare selected statically, that is, independent of any existing multicast groups and also theselection process is independent of any underlying unicast protocol. Some of theselected cores can be used for fault- tolerant purpose also to guard against any possible core failures. 3) We have presented two novel and efficient schemes forgroup-based load shared multicore multicasting in which members of a multicast groupuse the same core tree for their multicasting. 4) We also presented two schemes aim atachieving low latency multicasting along with load sharing for delay sensitive multicastapplications. Besides, we have presented a unique approach for core migration, whichuses two very important parameters, namely, depth of a core tree and pseudo diameterof a core. One noteworthy point from the viewpoint of fault tolerance is that the degreeof fault-tolerance can be enhanced from covering single point-failure to any number ofcore failures.
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Fang, Jun-Wai 1960. "Design and performance evaluation of a proposed backbone network for PC-Networks interconnection." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276941.
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This thesis is concerned with the design of a high-speed backbone network which provides a high bandwidth interconnection for various Personal Computer Networks (PC-Networks) with an integrated service of voice and data. With the advanced technology of optical fiber as the transmission medium, several different existing topologies and protocols are discussed for the backbone network design. The token ring protocol is simulated and evaluated to find out a suitable buffer size and the length of voice and data packet for backbone network. The Network II.5 simulation tool is applied to simulate the token ring simulation model with different parameters. The Network Interface Unit (NIU) is designed from the simulation results with a cost-effective consideration.
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Reed, Jonathan Michael. "Design and Implementation of the FINS Framework: Flexible Internetwork Stack." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/49153.
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This thesis describes the Flexible Internetwork Stack (FINS) Framework, an open-source tool to facilitate experimental research in wireless networks on multiple platforms. The FINS Framework uses a module-based architecture that allows cross-layer behavior and runtime reconfiguration of the protocol stack. Version 1.0 of the framework makes use of existing physical and data link layer functionality, while enabling modifications to the stack at the network layer and above, or even the implementation of a clean-slate, non-layered protocol architecture. Protocols, stubs for communicating with intact layers, and management and supervisory functions are implemented as FINS Framework modules, interconnected by a central switch. This thesis describes the FINS Framework architecture, presents an initial assessment along with experiments on Android and Ubuntu enabled by the tool, and documents an intuitive mechanism for transparently intercepting socket calls that maintains efficiency and flexibility.Master of Science
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(6872636), Yiyang Chang. "Ensuring Network Designs Meet Performance Requirements under Failures." Thesis, 2019.
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With the prevalence of web and cloud-based services, there is an ever growing requirement on the underlying network infrastructure to ensure that business critical traffic is continually serviced with acceptable performance. Networks must meet their performance requirements under failures. The global scale of cloud provider networks and the rapid evolution of these networks imply that failures are the norm in production networks today. Unplanned downtime can cost billions of dollars, and cause catastrophic consequences. The thesis is motivated by these challenges and aims to provide a principled solution to certifying network performance under failures. Network performance certification is complicated, due to both the variety of ways a network can fail, and the rich ways a network can respond to failures. The key contributions of this thesis are: (i) a general framework for robustly certifying the worst-case performance of a network across a given set of uncertain scenarios. A key novelty is that the framework models flexible network response enabled by recent emerging trends such as Software-Defined Networking; (ii) a toolkit which automates the key steps needed in robust certification making it suitable for use by a network architect, and which enables experimentation on a wide range of robust certification of practical interest; (iii) Slice, a general framework which efficiently classifies failure scenarios based on whether network performance is acceptable for those scenarios, and which allows reasoning about performance requirements that must be met over a given percentage of scenarios. We also show applications of our frameworks in synthesizing designs that are guaranteed to meet a performance goal over all or a desired percentage of a given set of scenarios. The thesis focuses on wide-area networks, but the approaches apply to data-center networks as well.
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Chen, Rong-Jyh, and 陳榮志. "Neural Network Based Robust Filtering Designs." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/07303848502284650130.
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碩士國立臺灣海洋大學
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In general, the navigation information has been processed by the Kalman filter. The filtering algorithm requires the knowledge that all the system strength (i.e., the system model , initial condition, and noise characteristics) have to be specified a priori. However, if there is uncertainty in any of these characteristics, the filter may not be robust enough. The robust filter is expected to perform better solutions than the Kalman filter when there are uncertainties in both process and measurement models. Howerver, the filters that perform robust estimation usually require iteration proceduce before the robust estimate is obtained, In this thesis, we propose a neural network learning algorithm to implement the relationship between the input covariances and the optimal Kalman gain. After the learning process is completed, a mapping that relates the input covariance matrices to the optimal Kalman gains can be obtained. In this case, we do not need the iteration process for obtaining optimal Kalman gains.
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Kumar, Reeshav. "Communication Reliability in Network on Chip Designs." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10080.
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The performance of low latency Network on Chip (NoC) architectures, which incorporate fast bypass paths to reduce communication latency, is limited by crosstalk induced skewing of signal transitions on link wires. As a result of crosstalk interactions between wires, signal transitions belonging to the same flit or bit vector arrive at the destination at different times and are likely to violate setup and hold time constraints for the design. This thesis proposes a two-step technique: TransSync- RecSync, to dynamically eliminate packet errors resulting from inter-bit-line transition skew. The proposed approach adds minimally to router complexity and involves no wire overhead. The actual throughput of NoC designs with asynchronous bypass designs is evaluated and the benefits of augmenting such schemes with the proposed design are studied. The TransSync, TransSync-2-lines and RecSync schemes described here are found to improve the average communication latency by 26%, 20% and 38% respectively in a 7X7 mesh NoC with asynchronous bypass channel.
This work also evaluates the bit-error ratio (BER) performance of several existing crosstalk avoidance and error correcting schemes and compares them to that of the proposed schemes. Both TransSync and RecSync scheme are dynamic in nature and can be switched on and off on-the-fly. The proposed schemes can therefore be employed to impart unequal error protection (UEP) against intra-flit skewing on NoC links. In the UEP, a larger fraction of the energy budget is spent in providing protection to those parts of the data being transmitted on the link which have a higher priority, while expending smaller effort in protecting relatively less important parts of the data. This allows us to achieve the prescribed level of performance with lower levels of power. The benefits of the presented technique are illustrated using an H.264 video decoder system-on-chip (SoC) employing NoC architecture. We show that for Akyio test streams transmitted over 3mm long link wires, the power consumption can be reduced by as much as 20% at the cost of an acceptable degradation in average peak signal to noise ratio (PSNR) with UEP.
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Derrible, Sybil. "The Properties and Effects of Metro Network Designs." Thesis, 2010. http://hdl.handle.net/1807/26164.
Full textAbstract:
Since 2008, more than half of the world population lives in cities. To cope with this rapid urbanization in a sustainable manner, transit systems all around the world are likely to grow. By studying 33 networks in the world, this thesis identifies the properties and effects of metro network designs by using a graph theory approach.
After the literature review, a new methodology was introduced to translate networks into graphs; it notably accounts for various transit specificities (e.g., presence of lines). Metro networks were then characterised according to their State, Form, and Structure; where State relates to the development phase of metros; Form investigates the link between metros and the built environment; Structure examines the intrinsic properties of metros, by notably looking at their connectivity. Subsequently, the complexity and robustness of metros were studied; metros were found to possess scale-free and small-world features although showing atypical topologies; robustness emphasizes on the presence of alternative paths. Three network design indicators (coverage, directness and connectivity) were then related to ridership (annual boardings per capita), and positive relations were observed, which suggests that network design plays an important role in their success. Finally, these concepts were applied to the Toronto metro plans announced by the Toronto regional transportation authority, Metrolinx; it was found that the grid-pattern nature of the plans could hinder the success of the metro; seven possible improvements were suggested.
Overall, the topology of metro networks can play a key role in their success. The concepts presented here can particularly be useful to transit planners; they should also be used along with conventional planning techniques. New transit projects could benefit greatly from an analysis of their network designs, which in turn may play a relevant role in the global endeavour for sustainability.
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Lei, Yung-Chun, and 雷永群. "On Task Clustering for Network-on-Chip Designs." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/73503902464514426112.
Full textAbstract:
碩士國立交通大學
電子工程系所
93
The Network-on-Chip (NoC) has become a new trend in on-chip system communication design. We have developed a complete design flow for NoC system design. In this thesis we focus on the task clustering in our NoC design flow. The task clustering problem in the NoC system design needs to consider multiple constraints, which include computing power, memory, I/O and communication bandwidth. We introduce an algorithm to minimize the number of clusters in the result with all constraints being met. The algorithm has been written as an automatic program and some experimental results are presented. Using our program, we can reduce the number of clusters with all constraints satisfied in few minutes.
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Liou, Ching-Kuo, and 劉清國. "T Network-Based Downconverter Designs for WMAN Applications." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/79530573779354289512.
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