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2009

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Articles 1321 - 1342 of 1342

Full-Text Articles in Computer Sciences

Partially Materialized Digest Scheme: An Efficient Verification Method For Outsourced Databases, Kyriakos Mouratidis, Dimitris Sacharidis, Hwee Hwa Pang Jan 2009

Partially Materialized Digest Scheme: An Efficient Verification Method For Outsourced Databases, Kyriakos Mouratidis, Dimitris Sacharidis, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

In the outsourced database model, a data owner publishes her database through a third-party server; i.e., the server hosts the data and answers user queries on behalf of the owner. Since the server may not be trusted, or may be compromised, users need a means to verify that answers received are both authentic and complete, i.e., that the returned data have not been tampered with, and that no qualifying results have been omitted. We propose a result verification approach for one-dimensional queries, called Partially Materialized Digest scheme (PMD), that applies to both static and dynamic databases. PMD uses separate indexes …


Multiple Dataset Visualization (Mdv) Framework For Scalar Volume Data, Gaurav Khanduja Jan 2009

Multiple Dataset Visualization (Mdv) Framework For Scalar Volume Data, Gaurav Khanduja

LSU Doctoral Dissertations

Many applications require comparative analysis of multiple datasets representing different samples, conditions, time instants, or views in order to develop a better understanding of the scientific problem/system under consideration. One effective approach for such analysis is visualization of the data. In this PhD thesis, we propose an innovative multiple dataset visualization (MDV) approach in which two or more datasets of a given type are rendered concurrently in the same visualization. MDV is an important concept for the cases where it is not possible to make an inference based on one dataset, and comparisons between many datasets are required to reveal …


Computational Techniques For Reducing Spectra Of The Giant Planets In Our Solar System, Holly L. Grimes Jan 2009

Computational Techniques For Reducing Spectra Of The Giant Planets In Our Solar System, Holly L. Grimes

Dissertations and Theses

The dynamic atmospheres of Jupiter, Saturn, Uranus, and Neptune provide a rich source of meteorological phenomena for scientists to study. To investigate these planets, scientists obtain spectral images of these bodies using various instruments including the Cooled Mid-Infrared Camera and Spectrometer (COMICS) at the Subaru Telescope Facility at Mauna Kea, Hawaii. These spectral images are two-dimensional arrays of double precision floating point values that have been read from a detector array. Such images must be reduced before the information they contain can be analyzed. The reduction process for spectral images from COMICS involves several steps:

1. Sky subtraction: the …


Object Reuse And Exchange, Michael L. Nelson, Carl Lagoze, Herbert Van De Sompel, Pete Johnston, Robert Sanderson, Simeon Warner, Jürgen Sieck (Ed.), Michael A. Herzog (Ed.) Jan 2009

Object Reuse And Exchange, Michael L. Nelson, Carl Lagoze, Herbert Van De Sompel, Pete Johnston, Robert Sanderson, Simeon Warner, Jürgen Sieck (Ed.), Michael A. Herzog (Ed.)

Computer Science Faculty Publications

The Open Archives Object Reuse and Exchange (OAI-ORE) project defines standards for the description and exchange of aggregations of Web resources. The OAI-ORE abstract data model is conformant with the Architecture of the World Wide Web and leverages concepts from the Semantic Web, including RDF descriptions and Linked Data. In this paper we provide a brief review of a motivating example and its serialization in Atom.


Everyone Is A Curator: Human-Assisted Preservation For Ore Aggregations, Frank Mccown, Michael L. Nelson, Herbert Van De Sompel Jan 2009

Everyone Is A Curator: Human-Assisted Preservation For Ore Aggregations, Frank Mccown, Michael L. Nelson, Herbert Van De Sompel

Computer Science Faculty Publications

The Open Archives Initiative (OAI) has recently created the Object Reuse and Exchange (ORE) project that defines Resource Maps (ReMs) for describing aggregations of web resources. These aggregations are susceptible to many of the same preservation challenges that face other web resources. In this paper, we investigate how the aggregations of web resources can be preserved outside of the typical repository environment and instead rely on the thousands of interactive users in the web community and the Web Infrastructure (the collection of web archives, search engines, and personal archiving services) to facilitate preservation. Inspired by Web 2.0 services such as …


Correlation Of Music Charts And Search Engine Rankings, Martin Klein, Olena Hunsicker, Michael Nelson Jan 2009

Correlation Of Music Charts And Search Engine Rankings, Martin Klein, Olena Hunsicker, Michael Nelson

Computer Science Faculty Publications

We investigate the question whether expert rankings of real-world entities correlate with search engine (SE) rankings of corresponding web resources. We compare Billboards "Hot 100 Airplay" music charts with SE rankings of associated web resources. Out of nine comparisons we found two strong, two moderate, two weak and one negative correlation. The remaining two comparisons were inconclusive.


Multicast Encryption Infrastructure For Security In Sensor Networks, Richard R. Brooks, Brijesh Pillai, Matthew Pirretti, Michele C. Weigle Jan 2009

Multicast Encryption Infrastructure For Security In Sensor Networks, Richard R. Brooks, Brijesh Pillai, Matthew Pirretti, Michele C. Weigle

Computer Science Faculty Publications

Designing secure sensor networks is difficult. We propose an approach that uses multicast communications and requires fewer encryptions than pairwise communications. The network is partitioned into multicast regions; each region is managed by a sensor node chosen to act as a keyserver. The keyservers solicit nodes in their neighborhood to join the local multicast tree. The keyserver generates a binary tree of keys to maintain communication within the multicast region using a shared key. Our approach supports a distributed key agreement protocol that identifies the compromised keys and supports membership changes with minimum system overhead. We evaluate the overhead of …


Evaluating Multicore Algorithms On The Unified Memory Model, John E. Savage, Mohammad Zubair Jan 2009

Evaluating Multicore Algorithms On The Unified Memory Model, John E. Savage, Mohammad Zubair

Computer Science Faculty Publications

One of the challenges to achieving good performance on multicore architectures is the effective utilization of the underlying memory hierarchy. While this is an issue for single-core architectures, it is a critical problem for multicore chips. In this paper, we formulate the unified multicore model (UMM) to help understand the fundamental limits on cache performance on these architectures. The UMM seamlessly handles different types of multiple-core processors with varying degrees of cache sharing at different levels. We demonstrate that our model can be used to study a variety of multicore architectures on a variety of applications. In particular, we use …


The Hamiltonian Index Of Graphs, Yi Hong, Jian-Liang Lin, Zhi-Sui Tao, Zhi-Hong Chen Jan 2009

The Hamiltonian Index Of Graphs, Yi Hong, Jian-Liang Lin, Zhi-Sui Tao, Zhi-Hong Chen

Scholarship and Professional Work - LAS

The Hamiltonian index of a graph G is defined as h ( G ) = min { m : L m ( G ) is Hamiltonian } . In this paper, using the reduction method of Catlin [P.A. Catlin, A reduction method to find spanning Eulerian subgraphs, J. Graph Theory 12 (1988) 29–44], we constructed a graph H ̃ ( m ) ( G ) from G and prove that if h ( G ) ≥ 2 , then h ( G ) = min{ m : H ̃ ( m ) ( G ) has a spanning Eulerian subgraph …


Dynamic Adaptation Of Joint Transmission Power And Contention Window In Vanet, Danda B. Rawat, Gongjun Yan, Dimitrie C. Popescu, Michele C. Weigle, Stephan Olariu Jan 2009

Dynamic Adaptation Of Joint Transmission Power And Contention Window In Vanet, Danda B. Rawat, Gongjun Yan, Dimitrie C. Popescu, Michele C. Weigle, Stephan Olariu

Electrical & Computer Engineering Faculty Publications

In this paper, we propose an algorithm for joint adaptation of transmission power and contention window to improve the performance of vehicular network in a cross layer approach. The high mobility of vehicles in vehicular communication results in the change in topology of the Vehicular Ad-hoc Network (VANET) dynamically, and the communication link between two vehicles might remain active only for short duration of time. In order for VANET to make a connection for long time and to mitigate adverse effects due to high and fixed transmission power, the proposed algorithm adapts transmission power dynamically based on estimated local traffic …


High-Performance Broadcast And Multicast Protocols For Multi-Radio Multi-Channel Wireless Mesh Networks, Jun Wang Jan 2009

High-Performance Broadcast And Multicast Protocols For Multi-Radio Multi-Channel Wireless Mesh Networks, Jun Wang

Electrical & Computer Engineering Theses & Dissertations

Recently, wireless mesh networks (WMNs) have attracted much attention. A vast amount of unicast, multicast and broadcast protocols has been developed for WMNs or mobile ad hoc networks (MANETs). First of all, broadcast and multicast in wireless networks are fundamentally different from the way in which wired networks function due to the well-known wireless broadcast/multicast advantage. Moreover, most broadcast and multicast protocols in wireless networks assume a single-radio single-channel and single-rate network model, or a generalized physical model, which does not take into account the impact of interference. This dissertation focuses on high-performance broadcast and multicast protocols designed for multi-radio …


Supporting Protocols For Structuring And Intelligent Information Dissemination In Vehicular Ad Hoc Networks, Filip Cuckov Jan 2009

Supporting Protocols For Structuring And Intelligent Information Dissemination In Vehicular Ad Hoc Networks, Filip Cuckov

Electrical & Computer Engineering Theses & Dissertations

The goal of this dissertation is the presentation of supporting protocols for structuring and intelligent data dissemination in vehicular ad hoc networks (VANETs). The protocols are intended to first introduce a structure in VANETs, and thus promote the spatial reuse of network resources. Segmenting a flat VANET in multiple cluster structures allows for more efficient use of the available bandwidth, which can effectively increase the capacity of the network. The cluster structures can also improve the scalability of the underlying communication protocols. The structuring and maintenance of the network introduces additional overhead. The aim is to provide a mechanism for …


Performance Study Of Fmipv6-Based Cross-Layer Wimax Handover Scheme For Supporting Voip Service, Heejung Kim Jan 2009

Performance Study Of Fmipv6-Based Cross-Layer Wimax Handover Scheme For Supporting Voip Service, Heejung Kim

Master's Projects

This report presents performance study of the FMIPv6-based cross-layer handover scheme for VoIP supports over mobile WiMAX network. For this performance validation and evaluation, the handover delays for four different handover mechanisms are formulated and ns2 based simulation module has been developed. The handover delay, the total delay, and the R factor representing VoIP quality are measured to evaluate the VoIP support characteristics of the FMIPv6-based cross-layer scheme. Simulation results verified that the proposed FMIPv6-based cross-layer handover scheme, compared to the non-cross-layer scheme, successfully reduces total handover delay by almost 50% for the case of layer-3 handover. Further, simulation was …


Video Conferencing Tool, Sapna Blesson Jan 2009

Video Conferencing Tool, Sapna Blesson

Master's Projects

Video Conferencing Tool (VCT) is a web-based video chat application that allows users anywhere in the world to join real-time streaming video chat rooms. This product is similar to social networking sites that allow web-based video conferencing. The main advantage of VCT compared to existing tools is that it is easy to use and does not require users to download and set up additional hardware. Since this product is a browser-based solution, it allows users from multiple platforms like Windows, Linux, or Mac to join a chat room. My VCT allows users to create new public or private chat rooms …


Dna Sequence Representation By Use Of Statistical Finite Automata, Asmi Shah Jan 2009

Dna Sequence Representation By Use Of Statistical Finite Automata, Asmi Shah

Master's Projects

This project defines and intends to solve the problem of representing information carried by DNA sequences in terms of amino acids, through application of the theory of finite automata. Sequences can be compared against each other to find existing patterns, if any, which may include important genetic information. Comparison can state whether the DNA sequences belong to the same, related or entirely different species in the ‘Tree of Life’ (phylogeny). This is achieved by using extended and statistical finite automata. In order to solve this problem, the concepts of automata and their extension, i.e. Alergia algorithm have been used. In …


Intrusion Alerts Analysis Using Attack Graphs And Clustering, Hardik Patel Jan 2009

Intrusion Alerts Analysis Using Attack Graphs And Clustering, Hardik Patel

Master's Projects

Network and information security is very crucial in keeping large information infrastructures safe and secure. Many researchers have been working on different issues to strengthen and measure security of a network. An important problem is to model security in order to apply analysis schemes efficiently to that model. An attack graph is a tool to model security of a network which considers individual vulnerabilities in a global view where individual hosts are interconnected. The analysis of intrusion alert information is very important for security evaluation of the system. Because of the huge number of alerts raised by intrusion detection systems, …


Isolation And Dependency Resolution Of Presentation, Processing And Persistence, Mehrab Monjur Jan 2009

Isolation And Dependency Resolution Of Presentation, Processing And Persistence, Mehrab Monjur

Master's Theses (2009 -)

For business application development it is important to isolate programming efforts of the concerns: Presentation, Processing and Persistence. Development of each of these concerns has an independent thinking process and requires somewhat different programming languages and development tools. In order to isolate the concerns, we provide passages between the concerns and control the flow of execution by following essentially three rules: 1. Presentation and Processing are coroutines, 2. Processing is finished before Presentation can begin to show output, and 3. Persistence is a subsystem of Processing. We explain how these rules come to existence, and what the implications are in …


Compartmentalized Approach To The Assembly Of Physical Maps, Serdar Bozdag, Timothy J. Close, Stefano Lonardi Jan 2009

Compartmentalized Approach To The Assembly Of Physical Maps, Serdar Bozdag, Timothy J. Close, Stefano Lonardi

Mathematics, Statistics and Computer Science Faculty Research and Publications

Background

Physical maps have been historically one of the cornerstones of genome sequencing and map-based cloning strategies. They also support marker assisted breeding and EST mapping. The problem of building a high quality physical map is computationally challenging due to unavoidable noise in the input fingerprint data.

Results

We propose a novel compartmentalized method for the assembly of high quality physical maps from fingerprinted clones. The knowledge of genetic markers enables us to group clones into clusters so that clones in the same cluster are more likely to overlap. For each cluster of clones, a local physical map is first …


Development And Implementation Of High-Throughput Snp Genotyping In Barley, Timothy J. Close, Prasanna R. Bhat, Stefano Lonardi, Yonghui Wu, Nils Rostoks, Luke Ramsay, Arnis Druka, Nils Stein, Jan T. Svensson, Steve Wanamaker, Serdar Bozdag, Mikeal L. Roose, Matthew J. Moscou, Shiaoman Chao, Rajeev K. Varshney, Peter Szucs, Kazuhiro Sato, Patrick M. Hayes, David E. Matthews, Andris Kleinhofs, Gary J. Muehlbauer, Joseph Deyoung, David F. Marshall, Kavitha Madishetty, Raymond D. Fenton, Pascal Condamine, Andreas Graner, Robbie Waugh Jan 2009

Development And Implementation Of High-Throughput Snp Genotyping In Barley, Timothy J. Close, Prasanna R. Bhat, Stefano Lonardi, Yonghui Wu, Nils Rostoks, Luke Ramsay, Arnis Druka, Nils Stein, Jan T. Svensson, Steve Wanamaker, Serdar Bozdag, Mikeal L. Roose, Matthew J. Moscou, Shiaoman Chao, Rajeev K. Varshney, Peter Szucs, Kazuhiro Sato, Patrick M. Hayes, David E. Matthews, Andris Kleinhofs, Gary J. Muehlbauer, Joseph Deyoung, David F. Marshall, Kavitha Madishetty, Raymond D. Fenton, Pascal Condamine, Andreas Graner, Robbie Waugh

Mathematics, Statistics and Computer Science Faculty Research and Publications

Background

High density genetic maps of plants have, nearly without exception, made use of marker datasets containing missing or questionable genotype calls derived from a variety of genic and non-genic or anonymous markers, and been presented as a single linear order of genetic loci for each linkage group. The consequences of missing or erroneous data include falsely separated markers, expansion of cM distances and incorrect marker order. These imperfections are amplified in consensus maps and problematic when fine resolution is critical including comparative genome analyses and map-based cloning. Here we provide a new paradigm, a high-density consensus genetic map of …


Preferential Utilization Of Nadph As The Endogenous Electron Donor For Nad(P)H:Quinone Oxidoreductase 1 (Nqo1) In Intact Pulmonary Arterial Endothelial Cells, Robert D. Bongard, Brian J. Lindemer, Gary S. Krenz, Marilyn P. Merker Jan 2009

Preferential Utilization Of Nadph As The Endogenous Electron Donor For Nad(P)H:Quinone Oxidoreductase 1 (Nqo1) In Intact Pulmonary Arterial Endothelial Cells, Robert D. Bongard, Brian J. Lindemer, Gary S. Krenz, Marilyn P. Merker

Mathematics, Statistics and Computer Science Faculty Research and Publications

The goal was to determine whether endogenous cytosolic NAD(P)H:quinone oxidoreductase 1 (NQO1) preferentially uses NADPH or NADH in intact pulmonary arterial endothelial cells in culture. The approach was to manipulate the redox status of the NADH/NAD+ and NADPH/NADP+ redox pairs in the cytosolic compartment using treatment conditions targeting glycolysis and the pentose phosphate pathway alone or with lactate, and to evaluate the impact on the intact cell NQO1 activity. Cells were treated with 2-deoxyglucose, iodoacetate, or epiandrosterone in the absence or presence of lactate, NQO1 activity was measured in intact cells using duroquinone as the electron acceptor, and …


A Compartmentalized Approach To The Assembly Of Physical Maps, Serdar Bozdag, Timothy J. Close, Stefano Lonardi Jan 2009

A Compartmentalized Approach To The Assembly Of Physical Maps, Serdar Bozdag, Timothy J. Close, Stefano Lonardi

Mathematics, Statistics and Computer Science Faculty Research and Publications

Background: Physical maps have been historically one of the cornerstones of genome sequencing and map-based cloning strategies. They also support marker assisted breeding and EST mapping. The problem of building a high quality physical map is computationally challenging due to unavoidable noise in the input fingerprint data. Results: We propose a novel compartmentalized method for the assembly of high quality physical maps from fingerprinted clones. The knowledge of genetic markers enables us to group clones into clusters so that clones in the same cluster are more likely to overlap. For each cluster of clones, a local physical map is first …


Dendrites, Topological Graphs, And 2-Dominance, Paul Bankston Jan 2009

Dendrites, Topological Graphs, And 2-Dominance, Paul Bankston

Mathematics, Statistics and Computer Science Faculty Research and Publications

For each positive ordinal α, the reflexive and transitive binary relation of α-dominance between compacta was first defined in our paper [Mapping properties of co-existentially closed continua, Houston J. Math., 31 (2005), 1047-1063] using the ultracopower construction. Here we consider the important special case α =2, and show that any Peano compactum 2-dominated by a dendrite is itself a dendrite (with the same being true for topological graphs and trees). We also characterize the topological graphs that 2-dominate arcs (resp., simple closed curves) as those that have cut points of order 2 (resp., those that are not trees).