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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A diagnostics model for industrial communications networks

Kaghazchi, Hassan January 2015 (has links)
Over the past twenty years industrial communications networks have become common place in most industrial plants. The high availability of these networks is crucial in smooth plant operations. Therefore local and remote diagnostics of these networks is of primary importance in solving any existing or emerging network problems. Users for most part consider the “plant networks” as black boxes, and often not sure of the actual health of the networks. The major part of the work outlined in this research concentrates on the proposed “Network Diagnostics Model” for local and remote monitoring. The main objective of the research is to aid the establishment of tools and techniques for diagnosis of the industrial networks, with particular emphasis on PROFIBUS and PROFINET. Additionally this research has resulted in development of a number of devices to aid in network diagnostics. The work outlined in this submission contributes to the developments in the area of online diagnostics systems. The development work was conducted in the following phases: 1. Development of Function Block (FB) for diagnosing PROFIBUS network for implementation on PLC. 2. Development of OPC server for diagnosing PROFIBUS network for implementation on PC. 3. Development of a web based diagnostic software for multiple fieldbuses for implementation on imbedded XP platform. 4. Development of OPC server for diagnosing PROFINET network for implementation on PC 5. Conformance testing of masters (PLC) in PROFIBUS network to increase the health of the network. 6. Use of diagnostics tools for performance analysis of fieldbuses networks for high performance applications. The research work outlined in this submission has made a significant and coherent contribution to online diagnostics of fieldbus communications networks, and has paved the way for the introduction of the online diagnostics devices to the market place. It has shown that the proposed model provides a uniform framework for research and development of diagnostics tools and techniques for fieldbus networks. Organizations that use fieldbus should consider installing advanced online diagnostic systems to boost maintenance efficiency and reduce operating costs, and maintain the availability of plant resources. Based on the experience gained over a number of years a multilayer model is proposed for future development of diagnostics tools.
2

Nonlinear identification using local model networks

McLoone, Seamus Cornelius January 2000 (has links)
No description available.
3

Analyzing the robustness of telecommunication networks /

Eller, Karol Schaeffer, January 1992 (has links)
Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1992. / Vita. Abstract. Includes bibliographical references (leaves 123-125). Also available via the Internet.
4

Q-fabric system support for continuous online quality management /

Poellabauer, Christian. January 2004 (has links) (PDF)
Thesis (Ph. D.)--Computing, Georgia Institute of Technology, 2004. / Pande, Santosh, Committee Member ; Pu, Calton, Committee Member ; Schwan, Karsten, Committee Chair ; Franke, Hubertus, Committee Member ; Eisenhauer, Greg, Committee Member. Vita. Includes bibliographical references (leaves 158-169).
5

The Impact Of Innovators’ Behaviour: a study on attractiveness and coordination

Lucchini, Lorenzo 27 May 2020 (has links)
Innovation is defined as the introduction of new things or methods. In the history of human society, progress and cultural evolution occurred as a consequence of innovation processes. Typically changes proposed by a restricted number of peoples became widely adopted innovations as soon as a broad consensus formed around their adoption. In this thesis, we explore the role of innovators as potentially influential individuals in our society. Studying their behaviour is crucial to understand what are the factors that drove their decision in the process of becoming influential. In particular, here we uncover the importance of cultural attractors as cities where strong akin communities are present. Our approach involves the use of Wikipedia as a source for historical mobility data to model the migration patterns of globally relevant innovators. While here we study mobility on a broad range of different disciplines where different innovators gave their contributions, we also focus on a smaller and more modern system. Historical innovators are easily identified and discerned from uninfluential ones thanks to the wisdom of the time. However, due to the scarce availability of individual historical data, we point our attention to more recent versions of innovators: code developer. The flourishment of the digital era made code developers at the very centre of our global economy. We study this coupled system as a representative example of the interaction between innovators and the economy. Indeed, a significant, non-trivial interaction is found among the two worlds. More in general, in this thesis we highlight the relevance of innovators in shaping human collective responses. Our results reveal that innovators play a major role both individually and collectively at different scales. We provide measures of these effects (i) by looking at how innovator communities construct the attractiveness of a city and (ii) by studying how individual contributions in the innovation domain can dramatically affect financial behaviour also at short time scales. Our result expands the evidence of the need for a new research dimension, where human behaviour is studied as a complex system moving over an intricate network of intertwined interactions.
6

Transmission congestion management by optimal placement of FACTS devices

Zeraatzade, Mahbube January 2010 (has links)
This thesis describes the implementation of the Flexible AC Transmission Systems (FACTS) devices to develop a market-based approach to the problem of transmission congestion management in a Balancing Market. The causes, remedies and pricing methods of transmission congestion are briefly reviewed. Balancing Market exists in markets in which most of the trading is done via decentralized bilateral contracts. In these markets only final adjustments necessary to ensure secure system operation is carried out at a centralized Balancing Market. Each market player can participate in the Balancing Market by submitting offers and bids to increase and decrease its initially submitted active generation output. In this research a method is proposed to reduce costs associated with congestion re-dispatch in a Balancing Market by optimal placement of FACTS devices, and in particular Thyristor Controlled Phase Shifter Transformers (TCPST). The proposed technique is applicable to both Mixed Integer Linear Programming (MILP) and Mixed Integer Non-Linear Programming (MINLP). In the MILP a power system network is represented by a simplified DC power flow under a MILP structure and the Market participants' offers and bids are also represented by linear models. Results show that applications of FACTS devices can significantly reduce costs of congestion re-dispatch. The application of the method based on the MINLP creates a nonlinear and non-convex AC OPF problem that might be trapped in local sub-optima solutions. The reliability of the solution that determines the optimal placement of FACTS devices is an important issue and is carried out by investigation of alternative solvers. The behavior of the MINLP solvers is presented and finally the best solvers for this particular optimization problem are introduced. The application of DC OPF is very common in industry. The accuracy of the DC OPF results is investigated and a comparison between the DC and AC OPF is presented.
7

Application of product family design for engineered systems in changing market space

Goswami, Mohit, January 2008 (has links) (PDF)
Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 19, 2008) Includes bibliographical references (p. 33-35).
8

Realistic mobility modeling and simulation for mobile wireless network in urban environments

Kim, Jonghyun. January 2005 (has links)
Thesis ( M.E.E.)--University of Delaware, 2005. / Principal faculty advisor: Stephan Bohacek, Dept. of Electrical & Computer Engineering. Includes bibliographical references.
9

Peer-to-Peer File Transfer in Wireless Mesh Networks

ElRakabawy, Sherif M., Lindemann, Christoph 17 December 2018 (has links)
In this paper, we consider the peer-to-peer transfer of popular files between devices in a wireless mesh network. We address the problem that occurs when multiple nodes try to access the same file simultaneously, resulting in increased contention on the shared wireless channel. To counteract this problem, we propose a cooperative file transfer protocol which splits a file into fixed-sized pieces and allows simultaneous downloads of such pieces from multiple peers. Opposed to previous approaches, the proposed protocol selects the potential download peers such that the corresponding download paths possess minimum interference among each other. In a performance study where we compare our approach with other download schemes proposed in the literature, we show that our cooperative protocol roughly halves the time required for downloading a file.
10

Optimal structures and collective dynamics of human flows in transportation networks.

Bontorin, Sebastiano 24 June 2024 (has links)
This thesis explores the dynamical and structural properties of human mobility within urban environments through the lens of complex systems and network science. Beginning with an introduction to the relevance of studying cities and human mobility, we outline our aim to investigate the interplay between transportation network properties and collective human flows. The theoretical background introduces essential concepts from network science and statistical physics, focusing on their application to spatial and transportation networks as well as urban systems. The thesis is devoted to three specific investigations. Firstly, we analyze the role of multiple pathways in defining effective network distances and their utility in predicting human mobility at diffusive scales, particularly in assessing pandemic potentials such as COVID-19 variants. Secondly, we delve into the optimization of flow-weighted transportation networks, demonstrating how network topologies can emerge from optimization processes under various constraints. We focus on a case study on the Greater London Area highlighting the integration of spatial attractiveness and traffic congestion in simulating human mobility patterns. The thesis finally explores the dynamics of out-of-routine mobility by integrating individual and collective behaviors. Leveraging large-scale datasets from US cities, we improve next-location prediction models by combining insights from individual trajectories and collective mobility dynamics. This approach is further examined in the context of novel mobility patterns influenced by COVID-19 restrictions, emphasizing the statistical properties of collective mobility near urban points of interests. Through these investigations, this thesis contributes to understanding complex urban systems and lays foundations for predictive models that integrate theoretical insights with empirical data to enhance our understanding of human mobility dynamics.

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