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Title: Connected Dominating Set in Wireless Ad Hoc Networks: Variations with Applications.
Creator: Yang, Shuhui, Wu, Jie, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Wireless ad hoc networks (or simply ad hoc networks) are infrastructureless multihop networks consisting of mobile or stationary wireless devices, which include mobile ad hoc networks (MANETs) and wireless sensor networks (WSNs). These networks are characterized by limited bandwidth and energy resources, frequent topology changes, and a lack of central control. These characteristics lead to the research challenges of ad hoc networks. The algorithms designed for ad hoc networks should be...
Show moreWireless ad hoc networks (or simply ad hoc networks) are infrastructureless multihop networks consisting of mobile or stationary wireless devices, which include mobile ad hoc networks (MANETs) and wireless sensor networks (WSNs). These networks are characterized by limited bandwidth and energy resources, frequent topology changes, and a lack of central control. These characteristics lead to the research challenges of ad hoc networks. The algorithms designed for ad hoc networks should be localized, selforganizing, and energy efficient. A connected dominating set (CDS) is frequently used in ad hoc networks as a virtual backbone to support efficient routing, service discovery, and area monitoring. In addition, efficient broadcasting (i.e., finding a small set of forward nodes to ensure full delivery) can be viewed as forming a CDS on-the-fly. The periodically maintained virtual backbone is called a static CDS, and the temporarily formed forward node set is called a dynamk CDS. For efficiency and robustness, the ideal CDS construction algorithm is lightweight, has fast convergence, and minimizes the CDS size. Recently, due to some specific applications and new techniques, the concept of a connected dominating set can be modified or further extended for more efficient usage. This dissertation focuses on the variations with applications of the connected dominating set, designing new concepts, and developing new algorithms for them. A review of CDS construction algorithms for ad hoc networks has been provided at the beginning. An efficient scheme, called Rule K, has been proposed for static CDS construction. Rule K achieves a probabilistic constant upper bound on the expected CDS size, which is currently the best known performance guarantee for localized CDS algorithms. Several CDS algorithms are extended to generate the extended CDS, which exploits the cooperative communication technique to further reduce the size of CDS. A k-coverage set is developed for higher robustness. With the equipment of directional antennas , the transmission can be restricted to some certain directions to reduce interference and energy consumption. The corresponding directional CDS is discussed. Finally, a wireless sensor and actor network (WSAN) is introduced and localized algorithms are designed for it.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012580
Subject Headings: Computer network protocols, Wireless communication systems--Design and construction, Mobile computing, Computer algorithms
Format: Document (PDF)

Title: Fault-tolerant multicasting in hypercube multicomputers.
Creator: Yao, Kejun., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Interprocessor communication plays an important role in the performance of multicomputer systems, such as hypercube multicomputers. In this thesis, we consider the multicast problem for a hypercube system in the presence of faulty components. Two types of algorithms are proposed. Type 1 algorithms, which are developed based on local network information, can tolerate both node failures and link failures. Type 2 algorithms, which are developed based on limited global network information, ensure...
Show moreInterprocessor communication plays an important role in the performance of multicomputer systems, such as hypercube multicomputers. In this thesis, we consider the multicast problem for a hypercube system in the presence of faulty components. Two types of algorithms are proposed. Type 1 algorithms, which are developed based on local network information, can tolerate both node failures and link failures. Type 2 algorithms, which are developed based on limited global network information, ensure that each destination receives message through the shortest path. Simulation results show that type 2 algorithms achieve very good results on both time and traffic steps, two main criteria in measuring the performance of interprocessor communication.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14896
Subject Headings: Hypercube networks (Computer networks), Computer architecture, Fault-tolerant computing
Format: Document (PDF)

Title: Fault tolerant scheduling for multiprocessor systems.
Creator: Mahanthi, Gangadhar., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: In the last few years, it has become profound to achieve higher performance of computers by solely upgrading logic technology. This required a move to a parallel processing system or a multiprocessor system in order to build faster computer systems. The importance of multiprocessor systems is increasing due to many reasons, one of which is reliability. In a multiprocessor system, a number of tasks may concurrently exist. To operate the system efficiently, one must carefully schedule the tasks...
Show moreIn the last few years, it has become profound to achieve higher performance of computers by solely upgrading logic technology. This required a move to a parallel processing system or a multiprocessor system in order to build faster computer systems. The importance of multiprocessor systems is increasing due to many reasons, one of which is reliability. In a multiprocessor system, a number of tasks may concurrently exist. To operate the system efficiently, one must carefully schedule the tasks. This thesis proposes a set of algorithms to schedule these tasks exploiting the inherent redundancy of processors in a multiprocessor system. Also discussed are some reliability issues and application to different networks with some examples.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14822
Subject Headings: Multiprocessors, Fault-tolerant computing, Electronic digital computers--Reliability
Format: Document (PDF)

Title: Enhanced Fibonacci Cubes.
Creator: Qian, Haifeng., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: We propose the enhanced Fibonacci cube (EFC), which is defined based on the sequence Fn = 2(n-2) + 2F(n-4). We study its topological properties, embeddings, applications, routings, VLSI/WSI implementations, and its extensions. Our results show that EFC retains many properties of the hypercube. It contains the Fibonacci cube (FC) and extended Fibonacci cube of the same order as subgraphs and maintains virtually all the desirable properties of FC. EFC is even better in some structural...
Show moreWe propose the enhanced Fibonacci cube (EFC), which is defined based on the sequence Fn = 2(n-2) + 2F(n-4). We study its topological properties, embeddings, applications, routings, VLSI/WSI implementations, and its extensions. Our results show that EFC retains many properties of the hypercube. It contains the Fibonacci cube (FC) and extended Fibonacci cube of the same order as subgraphs and maintains virtually all the desirable properties of FC. EFC is even better in some structural properties, embeddings, applications and VLSI designs than FC or hypercube. With EFC, there are more cubes with various structures and sizes for selection, and more backup cubes into which faulty hypercubes can be reconfigured, which alleviates the size limitation of the hypercube and results in a higher level of fault tolerance.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15196
Subject Headings: Integrated circuits--Very large scale integration, Hypercube networks (Computer networks), Algorithms, Fault-tolerant computing, Multiprocessors
Format: Document (PDF)

Title: Quality of service support in TDMA-based mobile ad hoc networks.
Creator: Jawhar, Imad., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: With the continuing advances in computing and wireless technologies, mobile ad hoc networks (MANETs) are expected to become an indispensable part of the computing environment in the near future. Wireless devices are constantly growing in computing speed, memory, communication capabilities and features, while shrinking in weight and size. With this growth and the proliferation of these devices in every aspect of society, the need for such devices to communicate in a seamless manner is becoming...
Show moreWith the continuing advances in computing and wireless technologies, mobile ad hoc networks (MANETs) are expected to become an indispensable part of the computing environment in the near future. Wireless devices are constantly growing in computing speed, memory, communication capabilities and features, while shrinking in weight and size. With this growth and the proliferation of these devices in every aspect of society, the need for such devices to communicate in a seamless manner is becoming increasingly essential. Multiple routing protocols have been developed for MANETs [51]. As MANETs gain popularity, their need to support real time and multimedia applications is growing as well. Such applications have stringent quality of service (QoS) requirements such as bandwidth, delay, and delay fitter. Design and development of routing algorithms with QoS support is experiencing increased research interest. Several approaches which propose various routing algorithms with QoS support for MANETs have been presented in research. This dissertation addresses the issues and challenges of QoS routing in MANETS and presents three new protocols which provide QoS support for this environment. First, a brief classification of existing QoS routing algorithms is provided. Then, the three new protocols for QoS routing support in MANETs are presented. These protocols focus on resource reservation for QoS provisioning in TDMA-based MANETs. The first protocol improves QoS support by eliminating racing conditions during multiple reservations of QoS paths. The second protocol is a new protocol for resource reservation for QoS support in TDMA-based MANETs using directional antennas. The last protocol provides dynamic range resource reservation for QoS support in MANETs and represents an extension of the previous protocols.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12158
Subject Headings: Digital communications, Time division multiple access, Computer algorithms, Computer network protocols, Wireless communication systems
Format: Document (PDF)

Title: Quorum based IP autoconfiguration in mobile ad hoc networks.
Creator: Xu, Tinghui., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: IP address autoconfiguration poses a challenge for mobile ad-hoc networks (MANETs) because it has to be done to ensure correct routing. An IP autoconfiguration protocol that is based on quorum voting is proposed. Nodes are distributed configured when a write quorum can be collected. Making the compromise between message overhead and data consistency, quorum voting enforces data consistency by ensuring fresh read on every access so that each node is configured with a unique IP address. The...
Show moreIP address autoconfiguration poses a challenge for mobile ad-hoc networks (MANETs) because it has to be done to ensure correct routing. An IP autoconfiguration protocol that is based on quorum voting is proposed. Nodes are distributed configured when a write quorum can be collected. Making the compromise between message overhead and data consistency, quorum voting enforces data consistency by ensuring fresh read on every access so that each node is configured with a unique IP address. The protocol is scalable since the configuration information is maintained locally and no central server is involved. Extensive experiments are carried out comparing the configuration latency, message overhead and address reclamation cost between our protocol and existing stateful protocols. The simulation results show that nodes are configured in lower latency and the message overhead for maintaining the network is fairly low. Moreover, the proposed protocol greatly enhances the address availability by keeping proper redundancy.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13362
Subject Headings: TCP/IP (Computer network protocol), Computer network architectures, Mobile communication systems, Wireless communication systems
Format: Document (PDF)

Title: The balanced hypercube: A versatile cube-based multicomputer system.
Creator: Huang, Ke., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: We propose the balanced hypercube (BH), which is a variant of the standard hypercube (Q), as a multicomputer topological structure. An n-dimensional balanced hypercube BHn has the same desirable topological properties of the 2n-dimensional standard hypercube Q2n such as size (2^2n nodes and n2^2n edges), regularity and symmetry, connectivity (2n node-disjoint pathes between any pair of nodes), and diameter (2n when n = 1 or n is even). Moreover, BHn has smaller diameter (2n-1) than Qn's (2n)...
Show moreWe propose the balanced hypercube (BH), which is a variant of the standard hypercube (Q), as a multicomputer topological structure. An n-dimensional balanced hypercube BHn has the same desirable topological properties of the 2n-dimensional standard hypercube Q2n such as size (2^2n nodes and n2^2n edges), regularity and symmetry, connectivity (2n node-disjoint pathes between any pair of nodes), and diameter (2n when n = 1 or n is even). Moreover, BHn has smaller diameter (2n-1) than Qn's (2n) when n is odd other than 1. In addition, BHn is load balanced, i.e., for every node v of BHn, there exists another node v', called v's matching node, such that v and v' share the same adjacent node set. Therefore, BHn has a desirable fault tolerance feature: when a node v fails, we can simply shift the job execution on v to its matching node v' and the communication pattern between jobs remains the same. In this dissertation, we study the topological properties of BHn and explore its fault tolerance feature. Other design issues are considered, such as communication primitives, capability of simulating other multicomputer systems through graph embedding, resource placement. and VLSI/WSI layout. Finally, the use of BHn is illustrated by an application.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/12519
Subject Headings: Hypercube networks (Computer networks), Fault-tolerant computing
Format: Document (PDF)

Title: XYZ: A scalable, partially centralized lookup service for large-scale peer-to-peer systems.
Creator: Zhang, Jianying., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Peer-to-Peer (P2P) systems are characterized by direct access between peer computers, rather than through a centralized server. File sharing is the dominant P2P application on the Internet, allowing users to easily contribute, search and obtain content. The objective of this thesis was to design XYZ, a partially centralized, scalable and self-organizing lookup service for wide area P2P systems. The XYZ system is based on distributed hash table (DHT). A unique ID and a color assigned to each...
Show morePeer-to-Peer (P2P) systems are characterized by direct access between peer computers, rather than through a centralized server. File sharing is the dominant P2P application on the Internet, allowing users to easily contribute, search and obtain content. The objective of this thesis was to design XYZ, a partially centralized, scalable and self-organizing lookup service for wide area P2P systems. The XYZ system is based on distributed hash table (DHT). A unique ID and a color assigned to each node and each file. The author uses clustering method to create the system backbone by connecting the cluster heads together and uses color clustering method to create color overlays. Any lookup for a file with a color will only be forwarded in the color overlay with the same color so that the searching space is minimized. Simulations and analysis are also provided in this thesis.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13263
Subject Headings: Wireless communication systems, Peer-to-peer architecture (Computer networks), Computational grids (Computer systems)
Format: Document (PDF)

Title: The design of reliable decentralized computer systems.
Creator: Wu, Jie., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: With the increase in the applications of computer technology, there are more and more demands for the use of computer systems in the area of real-time applications and critical systems. Reliability and performance are fundamental design requirements for these applications. In this dissertation, we develop some specific aspects of a fault-tolerant decentralized system architecture. This system can execute concurrent processes and it is composed of processing elements that have only local...
Show moreWith the increase in the applications of computer technology, there are more and more demands for the use of computer systems in the area of real-time applications and critical systems. Reliability and performance are fundamental design requirements for these applications. In this dissertation, we develop some specific aspects of a fault-tolerant decentralized system architecture. This system can execute concurrent processes and it is composed of processing elements that have only local memories with point-to-point communication. A model using hierarchical layers describes this system. Fault tolerance techniques are discussed for the applications, software, operating system, and hardware layers of the model. Scheduling of communicating tasks to increase performance is also addressed. Some special problems such as the Byzantine Generals problem are considered. We have shown that, by combining reliable techniques on different layers and with consideration of system performance, one can provide a system with a very high level reliability as well as performance.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/12237
Subject Headings: Electronic digital computers--Reliability, Fault-tolerant computing, System design, Computer software--Reliability
Format: Document (PDF)

Title: The effect of compression of performance in a demand paging operating system.
Creator: Wynn, Allen Chester., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: In this thesis, we measure and analyze the effects of compression in a demand paging operating system. We first explore existing compression algorithms and page replacement policies currently in use. Then we examine the OS/2 operating system which is modified to include page-based compression. Software trace hooks are inserted into the operating system to determine the amount of time required to process a page fault for each type of page, e.g. non-compressed, compressed, zero-filled, and the...
Show moreIn this thesis, we measure and analyze the effects of compression in a demand paging operating system. We first explore existing compression algorithms and page replacement policies currently in use. Then we examine the OS/2 operating system which is modified to include page-based compression. Software trace hooks are inserted into the operating system to determine the amount of time required to process a page fault for each type of page, e.g. non-compressed, compressed, zero-filled, and the number of page faults for each type of page. Software trace measurements as well as physical timings are taken on a system without compressed pages and the same system with compressed pages. We find the system with compressed pages shows a slight increase in paging activity for memory constrained systems, but performance (time) is improved in both memory constrained and unconstrained systems.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15421
Subject Headings: Paging (Computer science), Data compression (Computer science), Operating systems (Computers)
Format: Document (PDF)

Title: Fault-tolerant parallel computing using shuffle exchange hypercube and cube-connected cubes.
Creator: Goyal, Praduemn K., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: The hypercube has become one of the most popular architectures for a wide variety of parallel processing applications and has been used in several commercial and research multiprocessors. Its topological and reliability properties have been studied extensively and several techniques have been proposed for enhancing its reliability. We first present a survey of the techniques that have been used for analyzing and enhancing the reliability of the hypercube and propose a classification framework...
Show moreThe hypercube has become one of the most popular architectures for a wide variety of parallel processing applications and has been used in several commercial and research multiprocessors. Its topological and reliability properties have been studied extensively and several techniques have been proposed for enhancing its reliability. We first present a survey of the techniques that have been used for analyzing and enhancing the reliability of the hypercube and propose a classification framework in which the surveyed reliability analysis techniques can be critically evaluated. Invariably, the techniques for enhancing the fault tolerance of the hypercube require modification of the processing nodes to include redundant elements, or alternatively, degrade the hypercube to a lower dimension cube when faults occur. We propose a technique using unmodified processing elements that takes advantage of the dataflow patterns of a specific class of parallel algorithms belonging to the divide-and-conquer paradigm. It is shown that by incorporating shuffles and exchanges, the execution of the divide-and-conquer class of algorithms on the hypercube can be made fault- tolerant. We develop this technique into a fault-tolerant computing scheme for execution of divide-and-conquer class of parallel algorithms, which we call Shuffle Exchange Hypercube (SEH). We propose a new recursively defined interconnection architecture for parallel computation called Cube-Connected Cubes (CCCubes). It is shown that the CCCubes architecture can emulate both the hypercube and the Cube-Connected Cycles (CCC) architectures. The CCCubes architecture is recursively extended into the kth order Generalized Cube-Connected Cubes (GCCCubes) architecture. We propose several classes of CCCubes and GCCCubes architectures and study their topological and reliability properties. A comparison of the reliability and topological properties of the proposed architectures with those of the hypercube is provided and it is shown that the CCCubes and GCCCubes architectures present practical alternatives to the hypercube. Finally, some areas worthy of further pursuit are presented, which include the problem of determining a switch route schedule for SEH, extension of shuffles and exchanges to CCCubes and GCCCubes, and the determination of a VLSI layout for the proposed CCCubes and GCCCubes architectures.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/12581
Subject Headings: Fault-tolerant computing, Hypercube networks (Computer networks), Parallel processing (Electronic computers)
Format: Document (PDF)

Title: Local construction of connected dominating sets in wireless ad hoc networks.
Creator: Dai, Fei., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Wireless ad hoc networks are infrastructure-less multi-hop networks consisting of mobile (such as in mobile ad hoc networks) or stationary (such as in wireless sensor networks) wireless devices. These networks involve several challenges, including limited bandwidth and energy resources, frequent topology changes, and a lack of central control. Local acting, self-organizing, and self-healing algorithms (also called localized algorithms) are essential to the design of wireless ad hoc networks....
Show moreWireless ad hoc networks are infrastructure-less multi-hop networks consisting of mobile (such as in mobile ad hoc networks) or stationary (such as in wireless sensor networks) wireless devices. These networks involve several challenges, including limited bandwidth and energy resources, frequent topology changes, and a lack of central control. Local acting, self-organizing, and self-healing algorithms (also called localized algorithms) are essential to the design of wireless ad hoc networks. A connected dominating set (CDS) is frequently used in wireless ad hoc networks as a virtual backbone to support efficient routing, service discovery, and area monitoring. In addition, efficient broadcasting (i.e., finding a small set of forward nodes to ensure full delivery) can be viewed as forming a CDS on-the-fly. The periodically maintained virtual backbone is called a static CDS, and the temporarily formed forward node set is called a dynamic CDS. For efficiency and robustness, the ideal CDS construction algorithm is lightweight, has fast convergence, and minimizes the CDS size. This dissertation focuses on providing a generic framework to unify localized CDS construction schemes, including both static and dynamic CDS constructions, for wireless ad hoc networks. The goal is to provide insights on how to form a small CDS (forward node set) in dynamic networks with affordable overhead and high robustness. A classification of CDS construction algorithms for wireless ad hoc networks has been provided at the beginning. An efficient scheme, called Rule K, has been proposed for static CDS construction. Rule K achieves a probabilistic constant upper bound on the expected CDS size, which is currently the best known performance guarantee for localized CDS algorithms. Rule K has been extended to a unified framework, called the coverage condition, which contains most existing localized virtual backbone construction and efficient broadcast algorithms as its special cases. The coverage condition has been further extended to construct a k-connected k-dominating set for higher robustness, and integrated in an iterative process that further reduces the CDS size while maintaining the same level of robustness.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12144
Subject Headings: Wireless communication systems, Electronic digital computers--Power supply, Mobile computing, Sensor networks
Format: Document (PDF)

Title: Load balancing on multiprocessor systems.
Creator: More, Hemant B., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: The utilization of a multiprocessor system is enhanced when idle time of processors is reduced. Allocation of processes from overloaded processors to idle processors can balance the load on multiprocessor systems and increase system throughput by reducing the process execution time. This thesis presents a study of parameters, issues and existing algorithms related to load balancing. The performance of load balancing on hypercubes using three new algorithms is explored and analyzed. A new...
Show moreThe utilization of a multiprocessor system is enhanced when idle time of processors is reduced. Allocation of processes from overloaded processors to idle processors can balance the load on multiprocessor systems and increase system throughput by reducing the process execution time. This thesis presents a study of parameters, issues and existing algorithms related to load balancing. The performance of load balancing on hypercubes using three new algorithms is explored and analyzed. A new algorithm to balance load on hypercubes in the presence of link faults is presented and analyzed here. Another algorithm to balance load on hypercube systems containing faulty processors is proposed and studied. The applicability of load balancing to real life problems is demonstrated by showing that the execution of branch and bound problem on hypercubes speeds up when load balancing is used.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14957
Subject Headings: Hypercube networks (Computer networks), Multiprocessors, Fault-tolerant computing
Format: Document (PDF)

Title: Fault-tolerant distributed shared memories.
Creator: Brown, Larry., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Distributed shared memory (DSM) implements a shared-memory programming interface on message-passing hardware. The shared-memory programming paradigm offers several advantages over the message-passing paradigm. DSM is recognized as an important technology for massively parallel computing. However, as the number of processors in a system increases, the probability of a failure increases. To be widely useful, the DSM must be able to tolerate failures. This dissertation presents a method of...
Show moreDistributed shared memory (DSM) implements a shared-memory programming interface on message-passing hardware. The shared-memory programming paradigm offers several advantages over the message-passing paradigm. DSM is recognized as an important technology for massively parallel computing. However, as the number of processors in a system increases, the probability of a failure increases. To be widely useful, the DSM must be able to tolerate failures. This dissertation presents a method of implementing fault-tolerant DSM (FTDSM) that is based on the idea of a snooper. The snooper monitors DSM protocol messages and keeps a backup of the current state of the DSM. The snooper can respond on behalf of failed processors. The snooper-based FTDSM is an improvement over existing FTDSMs because it is based on the efficient dynamic distributed manager DSM algorithm, does not require the repair of a failed processor in access the DSM, and does not query all nodes to rebuild the state of the DSM. Three snooper-based FTDSM systems are developed. The single-snooper (SS) FTDSM has one snooper and is restricted to a broadcast network. Additional snoopers are added in the multiple-snooper (MS) FTDSM to improve performance. Two-phase commit (2PC) protocols are developed to coordinate the activities of the snoopers, and a special data structure is used to store causality information to reduce the amount of snooper activity. Snooping is integrated with each processor in the integrated snooper (IS) FTDSM. The IS FTDSM is scalable because it is not restricted to a broadcast network. The concept of dynamic snooping is introduced for the IS FTDSM and several snooper migration algorithms are studied. Several recovery algorithms are developed to allow failed processors to rejoin the system. The properties of data structures used to locate owners and snoopers are studied and used to prove that the system can tolerate any single fault. A flexible method of integrating application-level recovery with the FTDSM is presented, and a reliability analysis is conducted using a Markov-chain modeling tool to show that the snooper-based FTDSM is a cost effective way to improve the reliability of DSM.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/12349
Subject Headings: Fault-tolerant computing, Electronic data processing--Distributed processing, Parallel processing (Electronic computers), Computer networks
Format: Document (PDF)

Title: Fault-tolerant routing in two-dimensional and three-dimensional meshes.
Creator: Chen, Xiao., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Mesh-connected multicomputers are one of the simplest and least expensive structures to build a system using hundreds and even thousands of processors. The nodes communicate with each other by sending and receiving messages. As the system gets larger and larger, it not only requires the routing algorithms be efficient but also fault-tolerant. The fault model we use in 2-D meshes is a faulty block while in 3-D meshes, the fault model is a faculty cube. In order to route messages through...
Show moreMesh-connected multicomputers are one of the simplest and least expensive structures to build a system using hundreds and even thousands of processors. The nodes communicate with each other by sending and receiving messages. As the system gets larger and larger, it not only requires the routing algorithms be efficient but also fault-tolerant. The fault model we use in 2-D meshes is a faulty block while in 3-D meshes, the fault model is a faculty cube. In order to route messages through feasible minimum paths, the extended safety level is used to determine the existence of a minimal path and faulty block (cube) information is used to guide the routing. This dissertation presents an in-depth study of fault-tolerant minimal routing in 2-D tori, 3-D meshes, and tree-based fault-tolerant multicasting in 2-D and 3-D meshes using extended safety levels. Also path-based fault-tolerant deadlock-free multicasting in 2-D and 3-D meshes is studied. In fault-tolerant minimal routing in 2-D meshes, if no faulty block is encountered, any adaptive minimal routing can be used until the message encounters a faulty block. The next step is guided by the faulty block information until the message gets away from the faulty block. After that, any minimal adaptive routing can be used again. The minimal routing in 2-D tori is similar to that in 2-D meshes if at the beginning of the routing a conversion is made from a 2-D torus to a 2-D mesh. The fault-tolerant minimal routing in 3-D meshes can be done in a similar way. In the tree-based multicasting in 2-D and 3-D meshes, a time-step optimal and traffic-step suboptimal algorithm is proposed. Several heuristic strategies are presented to resolve a conflict, which are compared by simulations. A path-based fault-tolerant deadlock-free multicast algorithm in 2-D meshes with inter-block distance of at least three is presented to solve the deadlock problem in tree-based multicast algorithms. The approach is then extended to 3-D meshes and to inter-block distance of at least two in 2-D meshes. The path is Hamiltonian that is only updated locally in the neighborhood of a faulty block when a faulty block is encountered. Two virtual channels are used to prevent deadlock in 2-D and 3-D meshes with inter-block (inter-cube) distance of at least three and two more virtual channels are added if the inter-block distance is at least two.
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Date Issued: 1999
PURL: http://purl.flvc.org/fcla/dt/12597
Subject Headings: Fault-tolerant computing, Computer algorithms
Format: Document (PDF)

Title: Label routing protocol: A new cross-layer protocol for multi-hop ad hoc wireless network.
Creator: Wang, Yu., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Compared to the traditional wireless network, the multi-hop ad hoc wireless network (simply called ad hoc networks) is self-configurable, dynamic, and distributed. During the past few years, many routing protocols have been proposed for this particular network environment. While in wired and optical networks, multi-protocol label switching (MPLS) has clearly shown its advantages in routing and switching such as flexibility, high efficiency, scalability, and low cost, however MPLS is complex...
Show moreCompared to the traditional wireless network, the multi-hop ad hoc wireless network (simply called ad hoc networks) is self-configurable, dynamic, and distributed. During the past few years, many routing protocols have been proposed for this particular network environment. While in wired and optical networks, multi-protocol label switching (MPLS) has clearly shown its advantages in routing and switching such as flexibility, high efficiency, scalability, and low cost, however MPLS is complex and does not consider the mobility issue for wireless networks, especially for ad hoc networks. This thesis migrates the label concept into the ad hoc network and provides a framework for the efficient Label Routing Protocol (LRP) in such a network. The MAC layer is also optimized with LRP for shorter delay, power saving, and higher efficiency. The simulation results show that the delay is improved significantly with this cross-layer routing protocol.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13321
Subject Headings: Computer network protocols, Wireless communication systems, Mobile computing, Computer algorithms, MPLS standard, Operating systems (Computers)
Format: Document (PDF)

Title: Mobile agent and its application in distributed systems.
Creator: Khumanthem, Rajesh Singh., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Distributed computing has a lot of complex distributed control functions like mutual exclusion, data replication, load sharing, check pointing etc. The present study introduces two novel ways to address some of the issues in the first two areas---mutual exclusion and data replication with the use of mobile agent technology. This research work deals with analyzing the various advantages that Mobile Agent Technology provides and how its use can impact the design and development of distributed...
Show moreDistributed computing has a lot of complex distributed control functions like mutual exclusion, data replication, load sharing, check pointing etc. The present study introduces two novel ways to address some of the issues in the first two areas---mutual exclusion and data replication with the use of mobile agent technology. This research work deals with analyzing the various advantages that Mobile Agent Technology provides and how its use can impact the design and development of distributed system. The primary focus of this study is to present a clear view of the evolutionary path that will take us from the current technology to widespread use of mobile code and agents within the next few years.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13032
Subject Headings: Electronic data processing--Distributed processing, Mobile agents (Computer software)
Format: Document (PDF)

Title: A unified methodology for software and hardware fault tolerance.
Creator: Wang, Yijun., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: The growing demand for high availability of computer systems has led to a wide application range of fault-tolerant systems. In some real-time applications ultrareliable computer systems are required. Such computer systems should be capable of tolerating failures of not only their hardware components but also of their software components. This dissertation discusses three aspects of designing an ultrareliable system: (a) a hierarchical ultrareliable system structure; (b) a set of unified...
Show moreThe growing demand for high availability of computer systems has led to a wide application range of fault-tolerant systems. In some real-time applications ultrareliable computer systems are required. Such computer systems should be capable of tolerating failures of not only their hardware components but also of their software components. This dissertation discusses three aspects of designing an ultrareliable system: (a) a hierarchical ultrareliable system structure; (b) a set of unified methods to tolerate both software and hardware faults in combination; and (c) formal specifications in the system structure. The proposed hierarchical structure has four layers: Application, Software Fault Tolerance, Combined Fault Tolerance and Configuration. The Application Layer defines the structure of the application software in terms of the modular structure using a module interconnection language. The failure semantics of the service provided by the system is also defined at this layer. At the Software Fault Tolerance Layer each module can use software fault tolerance methods. The implementation of the software and hardware fault tolerance is achieved at the Combined Fault Tolerance Layer which utilizes the combined software/hardware fault tolerance methods. The Configuration Layer performs actual software and hardware resource management for the requests of fault identification and recovery from the Combined Fault Tolerance Layer. A combined software and hardware fault model is used as the system fault model. This model uses the concepts of fault pattern and fault set to abstract the various occurrences of software and hardware faults. We also discuss extended comparison models that consider faulty software as well. The combined software/hardware fault tolerance methods are based on recovery blocks, N-version programming, extended comparison methods and both forward and backward recovery methods. Formal specifications and verifications are used in the system design process and the system structure to show that the design and implementation of a fault-tolerant system satisfy the functional and non-functional requirements. Brief discussions and examples of using formal specifications in the hierarchical structure are given.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12424
Subject Headings: Fault-tolerant computing, Computer architecture
Format: Document (PDF)

Title: Embedding binomial trees in faulty hypercube multiprocessors.
Creator: Luo, Yinqiu., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: We study the embedding of binomial trees with variable roots in faulty hypercubes. Based on novel embedding strategies, we propose three embedding algorithms with variable nodes as the root. The first algorithm can tolerate up to n - 1 faulty links, but the execution can be done within log2(n - 1) subcube splits. The second one can tolerate up to [(3(n - 1))\2] faulty links. The last one can tolerate up to [(3(n - 4))\2] faulty nodes.
Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/15345
Subject Headings: Hypercube networks (Computer networks), Trees (Graph theory), Multiprocessors, Parallel processing (Electronic computers), Computer algorithms, Fault-tolerant computing, Embedded computer systems
Format: Document (PDF)

Title: Efficient Resource Discovery Technique in a Mobile Ad Hoc Networks.
Creator: Thanawala, Ravi, Wu, Jie, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: This thesis describes a resource discovery technique in mobile ad hoc networks. Resource discovery is technique to search data in among the mobile nodes in the network. The highly dynamic nature of the infrastructure-less ad hoc networks poses new challenges in resource discovery, thus there is a need to for an optimized resource discovery technique. Efficient resource discovery algorithm discovers the resources in a mobile ad-hoc network in an optimized way. As there is no pre-established...
Show moreThis thesis describes a resource discovery technique in mobile ad hoc networks. Resource discovery is technique to search data in among the mobile nodes in the network. The highly dynamic nature of the infrastructure-less ad hoc networks poses new challenges in resource discovery, thus there is a need to for an optimized resource discovery technique. Efficient resource discovery algorithm discovers the resources in a mobile ad-hoc network in an optimized way. As there is no pre-established infrastructure in the network, every node takes its decision in forwarding resources and every node dynamically ranks these resources before disseminating them in the network. Ranking of the resources spreads the data which is of high priority at that instance of time. Ranking avoids the spreads the unwanted or low priority data which will utilize the bandwidth unnecessarily. The efficient resource discovery algorithm also keeps a check that redundant information is not spread in the network with the available bandwidth and the bandwidth is utilized in an optimized manner. We then introduce brokers in the algorithm for a better performance. We present a technique to maintain a constant number of brokers in the network. Our simulations show that, in a network with high density, the efficient resource discovery algorithm gives a better performance than the flooding and rank based broadcast algorithms.
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Date Issued: 2008
PURL: http://purl.flvc.org/fau/fd/FA00012562
Subject Headings: Mobile communication systems--Mathematics, Computer algorithms, Wireless communication systems--Mathematics, Ad hoc networks (Computer networks)--Programming
Format: Document (PDF)

FAU Theses and Dissertations (45)	+ -
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