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Pages
- Title
- Active networking and innovation: An evaluation of active networking as a driver of accelerated Internet innovation.
- Creator
- Wood, James L., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Innovation has flourished at the edge of the Internet; however, the core has experienced a slower pace of innovation. This lag is impacting the pace of innovation at the edge and threatening quality as ad hoc solutions are implemented to overcome core network barriers to innovation. Active networking technology, which opens up the architecture of routers, is proposed as a standard solution. Researchers draw an analogy to the computer industry where innovation is claimed to be accelerated by...
Show moreInnovation has flourished at the edge of the Internet; however, the core has experienced a slower pace of innovation. This lag is impacting the pace of innovation at the edge and threatening quality as ad hoc solutions are implemented to overcome core network barriers to innovation. Active networking technology, which opens up the architecture of routers, is proposed as a standard solution. Researchers draw an analogy to the computer industry where innovation is claimed to be accelerated by modularization. This argument is valid to the extent that the router market is similar to the computer market; however, contemporary innovation theories cast doubt on this likelihood. These theories indicate that for active networking technology to accelerate Internet innovation, extraordinary measures will be required to break the status quo. This paper analyzes this situation and makes recommendations, based on innovation theory, on how active networking can be successful in accelerating Internet innovation.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fcla/dt/13161
- Subject Headings
- Computer industry--Technological innovations, Computer networks--Management, Computer networks--Software, Routers (Computer networks), Internetworking (Telecommunication)
- 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.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/12519
- Subject Headings
- Hypercube networks (Computer networks), Fault-tolerant computing
- Format
- Document (PDF)
- 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.
Show less - 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
- Design and modeling of hybrid software fault-tolerant systems.
- Creator
- Zhang, Man-xia Maria., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Fault tolerant programming methods improve software reliability using the principles of design diversity and redundancy. Design diversity and redundancy, on the other hand, escalate the cost of the software design and development. In this thesis, we study the reliability of hybrid fault tolerant systems. Probability models based on fault trees are developed for the recovery block (RB), N-version programming (NVP) and hybrid schemes which are the combinations of RB and NVP. Two heuristic...
Show moreFault tolerant programming methods improve software reliability using the principles of design diversity and redundancy. Design diversity and redundancy, on the other hand, escalate the cost of the software design and development. In this thesis, we study the reliability of hybrid fault tolerant systems. Probability models based on fault trees are developed for the recovery block (RB), N-version programming (NVP) and hybrid schemes which are the combinations of RB and NVP. Two heuristic methods are developed to construct hybrid fault tolerant systems with total cost constraints. The algorithms provide a systematic approach to the design of hybrid fault tolerant systems.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14783
- Subject Headings
- Computer software--Reliability, Fault-tolerant computing, Algorithms
- Format
- Document (PDF)
- Title
- Dynamic routing in grid-connected networks.
- Creator
- Jiang, Zhen., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This dissertation describes the effect of collection and distribution of fault information on routing capacity in grid-connected networks with faults occurring during the routing process. The grid-connected network, such as hypercubes, 2-D meshes, and 3-D meshes, is one of the simplest and least expensive structures to build a system using hundreds and even thousands of processors. In such a system, efficient communication among the processors is critical to performance. Hence, the routing of...
Show moreThis dissertation describes the effect of collection and distribution of fault information on routing capacity in grid-connected networks with faults occurring during the routing process. The grid-connected network, such as hypercubes, 2-D meshes, and 3-D meshes, is one of the simplest and least expensive structures to build a system using hundreds and even thousands of processors. In such a system, efficient communication among the processors is critical to performance. Hence, the routing of messages is an important issue that needs to be addressed. As the number of nodes in the networks increases, the chance of failure also increases. The complex nature of networks also makes them vulnerable to disturbances. Therefore, the ability to route messages efficiently in the presence of faulty components, especially those might occur during the routing process, is becoming increasingly important. A central issue in designing a fault-tolerant routing algorithm is the way fault information is collected and used. The safety level model is a special coded fault information model in hypercubes which is more cost effective and more efficient than other information models. In this model, each node is associated with an integer, called safety level, which is an approximated measure of the number and distribution of faulty nodes in the neighborhood. The safety level of each node in an n-dimensional hypercube can be easily calculated through (n - 1)-rounds information exchanges among neighboring nodes. A k-safe node indicates the existence of at least one Hamming distance path (also called optimal path or minimal path) from this node to any node with Hamming distance k. We focus on routing capacity using safety levels in a dynamic system. In this case, the update of safety levels and the routing process proceed hand-in-hand. During the converging period, the routing process may experience extra hops based on unstable (inconsistent) information. Under the assumption that the total number of faults is less than n, we provide an upper bound of extra hops and show its accuracy and effectiveness. After that, we extend the results to meshes. Our simulation results show the effectiveness of our information model and scalability of our fault-information-based routing in the grid-connected networks with dynamic faults. Because our information is easy to update and maintain and optimality is still preserved, it is more cost effective than the others.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12002
- Subject Headings
- Fault-tolerant computing, Hypercube networks (Computer networks)
- 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.
Show less - 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
- Efficient and Effective Searching m Unstructured FileSharing Peer-to-Peer Networks.
- Creator
- Li, Xiuqi, Wu, Jie, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Peer-to-peer (P2P) networking has been receiving increasing attention from the research community recently. How to conduct efficient and effective searching in such networks has been a challenging research topic. This dissertation focuses on unstructured file-sharing peer-to-peer networks. Three novel searching schemes are proposed, implemented, and evaluated. In the first scheme named ISRL (Intelligent Search by Reinforcement Learning), we propose to systematically learn the best route to...
Show morePeer-to-peer (P2P) networking has been receiving increasing attention from the research community recently. How to conduct efficient and effective searching in such networks has been a challenging research topic. This dissertation focuses on unstructured file-sharing peer-to-peer networks. Three novel searching schemes are proposed, implemented, and evaluated. In the first scheme named ISRL (Intelligent Search by Reinforcement Learning), we propose to systematically learn the best route to desired files through reinforcement learning when topology adaptation is impossible or infeasible. To discover the best path to desired files, ISRL not only explores new paths by forwarding queries to randomly chosen neighbors, but also exploits the paths that have been discovered for reducing the cumulative query cost. Three models of ISRL are put forwarded: a basic version for finding one desired file, MP-ISRL (MP stands for Multiple-Path ISRL) for finding at least k files, and C-ISRL (C refers to Clustering) for reducing maintenance overhead through clustering when there are many queries. ISRL outperforms existing searching approaches in unstructured peer-to-peer networks by achieving similar query quality with lower cumulative query cost. The experimental results confirm the performance improvement of ISRL. The second approach, HS-SDBF (Hint-based Searching by Scope Decay Bloom Filter), addresses the issue of effective and efficient hint propagation. We design a new data structure called SDBF (Scope Decay Bloom Filter) to represent and advertise probabilistic hints. Compared to existing proactive schemes, HSSDBF can answer many more queries successfully at a lower amortized cost considering both the query traffic and hint propagation traffic. Both the analytic and the experimental results support the performance improvement of our protocol. The third algorithm, hybrid search, seeks to combine the benefits of both forwarding and non-forwarding searching schemes. In this approach, a querying source directly probes its own extended neighbors and forwards a query to a subset of its extended neighbors and guides these neighbors to probe their own extended neighbors on its behalf. The hybrid search is able to adapt query execution to the popularity of desired files without generating too much state maintenance overhead because of the 1-hop forwarding inherent in the approach. It achieves a higher query efficiency than the forwarding scheme and a better success rate than the non-forwarding approach. To the best of our knowledge, this work is the first attempt to integrate forwarding and non-forwarding schemes. Simulation results demonstrate the effectiveness of the hybrid search.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fau/fd/FA00012572
- Subject Headings
- Peer-to-peer architecture (Computer networks), Computer security, Database searching, Internetworking (Telecommunication), Heterogeneous computing
- Format
- Document (PDF)
- Title
- Efficient localized broadcast algorithms in mobile ad hoc networks.
- Creator
- Lou, Wei., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The broadcast operation has a most fundamental role in mobile ad hoc networks because of the broadcasting nature of radio transmission, i.e., when a sender transmits a packet, all nodes within the sender's transmission range will be affected by this transmission. The benefit of this property is that one packet can be received by all neighbors while the negative effect is that it interferes with other transmissions. Flooding ensures that the entire network receives the packet but generates...
Show moreThe broadcast operation has a most fundamental role in mobile ad hoc networks because of the broadcasting nature of radio transmission, i.e., when a sender transmits a packet, all nodes within the sender's transmission range will be affected by this transmission. The benefit of this property is that one packet can be received by all neighbors while the negative effect is that it interferes with other transmissions. Flooding ensures that the entire network receives the packet but generates many redundant transmissions which may trigger a serious broadcast storm problem that may collapse the entire network. The broadcast storm problem can be avoided by providing efficient broadcast algorithms that aim to reduce the number of nodes that retransmit the broadcast packet while still guaranteeing that all nodes receive the packet. This dissertation focuses on providing several efficient localized broadcast algorithms to reduce the broadcast redundancy in mobile ad hoc networks. In my dissertation, the efficiency of a broadcast algorithm is measured by the number of forward nodes for relaying a broadcast packet. A classification of broadcast algorithms for mobile ad hoc networks has been provided at the beginning. Two neighbor-designating broadcast algorithms, called total dominant pruning and partial dominant pruning, have been proposed to reduce the number of the forward nodes. Several extensions based on the neighbor-designating approach have also been investigated. The cluster-based broadcast algorithm shows good performance in dense networks, and it also provides a constant upper bound approximation ratio to the optimum solution for the number of forward nodes in the worst case. A generic broadcast framework with K hop neighbor information has a trade-off between the number of the forward nodes and the size of the K-hop zone. A reliable broadcast algorithm, called double-covered broadcast, is proposed to improve the delivery ratio of a broadcast package when the transmission error rate of the network is high. The effectiveness of all these algorithms has been confirmed by simulations.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fau/fd/FADT12103
- Subject Headings
- Wireless LANS, Mobile communication systems, Wireless communication systems--Mathematics, Algorithms
- 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.
Show less - 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)
- 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
- 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.
Show less - 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
- 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.
Show less - 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
- 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.
Show less - 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 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.
Show less - 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 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.
Show less - 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
- 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
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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.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/12597
- Subject Headings
- Fault-tolerant computing, Computer algorithms
- Format
- Document (PDF)
- Title
- Improving Cooperation in P2P Networks: A Social Network Approach.
- Creator
- Ponce, Victor, Wu, Jie, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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Due to the dynamic nature of P2P systems, it is impossible to keep an accurate history of the transactions that take place while avoiding security attacks such as whitewashing and collusion, and abuse such as freeriding . This is why it is important to develop a mechanism that rewards cooperative peers and punishes misbehaving peers. Modeling P2P networks as social structures can allow incentive mechanisms to be used that prevent the negative behaviors mentioned. In this thesis, we extend a...
Show moreDue to the dynamic nature of P2P systems, it is impossible to keep an accurate history of the transactions that take place while avoiding security attacks such as whitewashing and collusion, and abuse such as freeriding . This is why it is important to develop a mechanism that rewards cooperative peers and punishes misbehaving peers. Modeling P2P networks as social structures can allow incentive mechanisms to be used that prevent the negative behaviors mentioned. In this thesis, we extend a social network algorithm to include credit transfer between peers in order to reduce the path length of queries. We also develop a selection strategy that involves different aspects of peer interactions in P2P networks, which is promoted by our credit transfer mechanism that discourages misbehaving peers by taking away credits that they have with good peers and transferring them to more cooperative ones. The simulation results show that our algorithm is effective in reducing the debt between peers, meaning that peers become more cooperative, and shortening the average path length to a satisfied query while increasing delivery ratio.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00012539
- Subject Headings
- Peer-to-peer architecture (Computer networks)--Technological innovations, Social interaction, Network analysis (Planning)
- Format
- Document (PDF)
- Title
- Key management in mobile ad hoc networks.
- Creator
- Wu, Bing., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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In mobile ad hoc networks (MANETs), providing secure communications is a big challenge due to unreliable wireless media, host mobility and lack of infrastructure. Usually, cryptographic techniques are used for secure communications in wired networks. Symmetric and asymmetric cryptography have their advantages and disadvantages. In fact, any cryptographic means is ineffective if its key management is weak. Key management is also a central aspect for security in mobile ad hoc networks. In...
Show moreIn mobile ad hoc networks (MANETs), providing secure communications is a big challenge due to unreliable wireless media, host mobility and lack of infrastructure. Usually, cryptographic techniques are used for secure communications in wired networks. Symmetric and asymmetric cryptography have their advantages and disadvantages. In fact, any cryptographic means is ineffective if its key management is weak. Key management is also a central aspect for security in mobile ad hoc networks. In MANETs, the computational load and complexity for key management are strongly subject to restriction by the node's available resources and the dynamic nature of network topology. We proposed a secure and efficient key management framework (SEKM) for MANETs. SEKM builds a PKI by applying a secret sharing scheme and using an underlying multicast server groups. In SEKM, each server group creates a view of the certificate authority (CA) and provides certificate update service for all nodes, including the servers themselves. Motivated by the distributed key management service, we introduced k-Anycast concept and proposed three k-anycast routing schemes for MANETs. k-anycast is proposed to deliver a packet to any threshold k members of a set of hosts. Our goal is to reduce the routing control messages and network delay to reach any k servers. The first scheme is called controlled flooding. The second scheme, called component-based scheme I, is to form multiple components such that each component has at least k members. The third scheme, called component-based scheme II, in which the membership a component maintains is relaxed to be less than k. Collaborative and group-oriented applications in MANETs is an active research area. Group key management is a central building block in securing group communications in MANETs. However, group key management for large and dynamic groups in MANETs is a difficult problem. We propose a simple and efficient group key management scheme that we named SEGK for MANETs, which is based on n-party Diffie-Hellman (DH). The basic idea of our scheme is that a physical multicast tree is formed in MANETs for efficiency. To achieve fault tolerance, double multicast trees are constructed and maintained. A group coordinator computes and distributes intermediate keying materials to all members through multicast tree links. All group members take turns acting as group coordinator and distributing the workload of group rekeying during any change of group membership. Every group member computes the group key in a distributed manner.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/12234
- Subject Headings
- Electronic commerce--Technological innovations, Mobile commerce--Technological innovations, Wireless communication systems--Management, Mobile communication systems--Management
- 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
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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.
Show less - 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
- 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
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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.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14957
- Subject Headings
- Hypercube networks (Computer networks), Multiprocessors, Fault-tolerant computing
- Format
- Document (PDF)
