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- 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
- Senescent and early diagenetic changes in chlorophyll.
- Creator
- Li, Jie, Florida Atlantic University, Baker, Earl W., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Aged unispecific cultures and environmental samples have been analyzed using HPLC-PDA in order to reveal chlorophyll-a degradation processes. Unispecific aging studies showed that alteration of chlorophyll occurred during senescence, and revealed that chlorophyll-a breakdown differs amongst various groups (i.e. species specificity). Sediment trap and sediment studies reveal that a variety of precursor chlorophyll-a derivatives are present, and that senescence and geochemistry, per se, overlap...
Show moreAged unispecific cultures and environmental samples have been analyzed using HPLC-PDA in order to reveal chlorophyll-a degradation processes. Unispecific aging studies showed that alteration of chlorophyll occurred during senescence, and revealed that chlorophyll-a breakdown differs amongst various groups (i.e. species specificity). Sediment trap and sediment studies reveal that a variety of precursor chlorophyll-a derivatives are present, and that senescence and geochemistry, per se, overlap strongly. Many of the reactions in the Treibs' scheme occur before and during deposition. Intracellular senescence and diagenetic pathways have been examined in this work. Comparison of aged unispecific cultures and environmental samples strongly suggests major in puts from the senescence pathway. The results further supports the concept "pyro" reaction (loss of the carbomethoxy group) fates chlorophyll diagenesis towards true DPEP compounds.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15455
- Subject Headings
- Chlorophyll, Algae, Plants--Aging, Diagenesis
- Format
- Document (PDF)
- Title
- Routing in mobile ad-hoc wireless networks.
- Creator
- Li, Hailan., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This thesis describes routing in mobile ad hoc wireless networks. Ad hoc networks are lack of wired backbone to maintain routes as mobile hosts move and power is on or off. Therefore, the hosts in ad hoc networks must cooperate with each other to determine routes in a distributed manner. Routing based on a connected dominating set is a frequently used approach, where the searching space for a route is reduced to nodes in small connected dominating set subnetwork. We propose a simple and...
Show moreThis thesis describes routing in mobile ad hoc wireless networks. Ad hoc networks are lack of wired backbone to maintain routes as mobile hosts move and power is on or off. Therefore, the hosts in ad hoc networks must cooperate with each other to determine routes in a distributed manner. Routing based on a connected dominating set is a frequently used approach, where the searching space for a route is reduced to nodes in small connected dominating set subnetwork. We propose a simple and efficient distributed algorithm for calculating connected dominating set in a given un-directed ad hoc network, then evaluate the proposed algorithm through simulation. We also discuss connected dominating set update/recalculation algorithms when the topology of the ad hoc network changes. We also explore the possible extension of using hierarchical connected dominating set. The shortest path routing and the dynamic source routing, which are based on the connected dominating set subnetwork, are discussed.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15695
- Subject Headings
- Mobile computing, Computer algorithms, Computer networks
- Format
- Document (PDF)
