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2010

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Articles 1411 - 1440 of 1584

Full-Text Articles in Computer Sciences

An Attempt To Find Neighbors, Yong Shi, Ryan Rosenblum Jan 2010

An Attempt To Find Neighbors, Yong Shi, Ryan Rosenblum

Faculty Articles

In this paper, we present our continuous research on similarity search problems. Previously we proposed PanKNN[18]which is a novel technique that explores the meaning of K nearest neighbors from a new perspective, redefines the distances between data points and a given query point Q, and efficiently and effectively selects data points which are closest to Q. It can be applied in various data mining fields. In this paper, we present our approach to solving the similarity search problem in the presence of obstacles. We apply the concept of obstacle points and process the similarity search problems in a different way. …


Visualization Of Complex Unsteady 3d Flow: Flowing Seed Points And Dynamically Evolving Seed Curves With Applications To Vortex Visualization In Cfd Simulations Of Ultra Low Reynolds Number Insect Flight, Christopher M. Koehler Jan 2010

Visualization Of Complex Unsteady 3d Flow: Flowing Seed Points And Dynamically Evolving Seed Curves With Applications To Vortex Visualization In Cfd Simulations Of Ultra Low Reynolds Number Insect Flight, Christopher M. Koehler

Browse all Theses and Dissertations

Three dimensional integration-based geometric visualization is a very powerful tool for analyzing flow phenomena in time dependent vector fields. Streamlines in particular have many perceptual benefits due to their ability to provide a snapshot of the vectors near key features of complex 3D flows at any instant in time. However, streamlines do not lend themselves well to animation. Subtle changes in the vector field at each time step lead to increasingly large changes between streamlines with the same seed point the longer they are integrated. Path lines, which show particle trajectories over time suffer from similar problems when attempting to …


Automatic Readability Assessment, Lijun Feng Jan 2010

Automatic Readability Assessment, Lijun Feng

Dissertations, Theses, and Capstone Projects

We describe the development of an automatic tool to assess the readability of text documents. Our readability assessment tool predicts elementary school grade levels of texts with high accuracy. The tool is developed using supervised machine learning techniques on text corpora annotated with grade levels and other indicators of reading difficulty. Various independent variables or features are extracted from texts and used for automatic classification. We systematically explore different feature inventories and evaluate the grade-level prediction of the resulting classifiers. Our evaluation comprises well-known features at various linguistic levels from the existing literature, such as those based on language modeling, …


Modeling Anticipatory Event Transitions, He Qi, Kuiyu Chang, Ee Peng Lim Jan 2010

Modeling Anticipatory Event Transitions, He Qi, Kuiyu Chang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Major world events such as terrorist attacks, natural disasters, wars, etc. typically progress through various representative stages/states in time. For example, a volcano eruption could lead to earthquakes, tsunamis, aftershocks, evacuation, rescue efforts, international relief support, rebuilding, and resettlement, etc. By analyzing various types of catastrophical and historical events, we can derive corresponding event transition models to embed useful information at each state. The knowledge embedded in these models can be extremely valuable. For instance, a transition model of the 1918-1920 flu pandemic could be used for the planning and allocation of resources to decisively respond to future occurrences of …


Do Online Reviews Reflect A Product's True Perceived Quality? An Investigation Of Online Movie Reviews Across Cultures, Noi Sian Koh, Nan Hu, Eric K. Clemons Jan 2010

Do Online Reviews Reflect A Product's True Perceived Quality? An Investigation Of Online Movie Reviews Across Cultures, Noi Sian Koh, Nan Hu, Eric K. Clemons

Research Collection School Of Computing and Information Systems

When does the reported average of online ratings match perceived average assessment? We apply behavioral theory to capture intentions in rating online movie reviews in two dissimilar countries - China and the United States. We argue that consumers' rating behaviors are affected by cultural influences. Based on data collected from imdb.com and douban.com, we found significant differences across raters from these two different cultures. Additionally, we examined how cultural elements influence rating behavior for a hybrid culture - Singapore. Under-reporting bias occurs when consumers with extreme opinions are more likely to report their opinions than consumers with moderate reviews, resulting …


Introducing Communication In Dis-Pomdps With Locality Of Interaction, Makoto Tasaki, Yuichi Yabu, Yuki Iwanari, Makoto Yokoo, Janusz Marecki, Pradeep Reddy Varakantham, Milind Tambe Jan 2010

Introducing Communication In Dis-Pomdps With Locality Of Interaction, Makoto Tasaki, Yuichi Yabu, Yuki Iwanari, Makoto Yokoo, Janusz Marecki, Pradeep Reddy Varakantham, Milind Tambe

Research Collection School Of Computing and Information Systems

The Networked Distributed POMDPs (ND-POMDPs) can model multiagent systems in uncertain domains and has begun to scale-up the number of agents. However, prior work in ND-POMDPs has failed to address communication. Without communication, the size of a local policy at each agent within the ND-POMDPs grows exponentially in the time horizon. To overcome this problem, we extend existing algorithms so that agents periodically communicate their observation and action histories with each other. After communication, agents can start from new synchronized belief state. Thus, we can avoid the exponential growth in the size of local policies at agents. Furthermore, we introduce …


Teleoph: A Secure Real-Time Teleophthalmology System, Yongdong Wu, Zhou Wei, Haixia Yao, Zhigang Zhao, Lek Heng Ngoh, Robert H. Deng, Shengsheng Yu Jan 2010

Teleoph: A Secure Real-Time Teleophthalmology System, Yongdong Wu, Zhou Wei, Haixia Yao, Zhigang Zhao, Lek Heng Ngoh, Robert H. Deng, Shengsheng Yu

Research Collection School Of Computing and Information Systems

Teleophthalmology (TeleOph) is an electronic counterpart of today's face-to-face, patient-to-specialist ophthalmology system. It enables one or more ophthalmologists to remotely examine a patient's condition via a confidential and authentic communication channel. Specifically, TeleOph allows a trained nonspecialist in a primary clinic to screen the patients with digital instruments (e.g., camera, ophthalmoscope). The acquired medical data are delivered to the hospital where an ophthalmologist will review the data collected and, if required, provide further consultation for the patient through a real-time secure channel established over a public Internet network. If necessary, the ophthalmologist is able to further sample the images/video of …


Workshop Report From Web2se: First Workshop On Web 2.0 For Software Engineering, Christoph Treude, Margaret-Anne Storey, Kate Ehrlich, Arie Van Deursen Jan 2010

Workshop Report From Web2se: First Workshop On Web 2.0 For Software Engineering, Christoph Treude, Margaret-Anne Storey, Kate Ehrlich, Arie Van Deursen

Research Collection School Of Computing and Information Systems

Web 2.0 technologies such as wikis, blogs, tags and feeds have been adopted and adapted by software engineers. With Web2SE, we provide a venue for pertinent work by highlighting current state-of-the-art research, by identifying research areas, and by discussing implications of Web 2.0 on software engineering. This paper reports on the paper presentations and the discussions among participants at Web2SE 2010 as well as on future directions of the Web2SE community.


Wisenetor: A Scalable Wireless Sensor Network Simulator, Gauri Krishna Gokhale Jan 2010

Wisenetor: A Scalable Wireless Sensor Network Simulator, Gauri Krishna Gokhale

Master's Projects

WiSeNetor is a teaching and a research tool that simulates a scalable wireless sensor network on a single computer, based on the “Spamulator” (Aycock, J., Crawford, H., & deGraaf, R., 2008) which simulates the Internet on a single computer. Routing protocols and network discovery algorithms used in mesh networks and cluster tree networks can be demonstrated using this tool. WiSeNetor contains a network creation module, simulated network devices and it simulates routing algorithms. The network creation module spawns a network according to user specified network type, where the type can be a cluster tree or mesh. In this process, neighbor …


Automatic Grading Of Programming Assignments, Ashlesha Patil Jan 2010

Automatic Grading Of Programming Assignments, Ashlesha Patil

Master's Projects

Solving practical problems is one of the important aspects of learning programming languages. But the assessment of programming problems is not straightforward. It involves time consuming and tedious steps required to compile and test the solution. In this project, I have developed a online tool, Javabrat that allows the students and language learners to practice Java and Scala problems. Javabrat automatically assesses the user's program and provides the instant feedback to the user. The users can also contribute their own programming problems to the existing problem set. I have also developed a plugin for a learning management system, Moodle. This …


Enhancing Open-Source Localization, Farzana Forhad Jan 2010

Enhancing Open-Source Localization, Farzana Forhad

Master's Projects

Pootle is a web portal which is designed to be a web translation tool. We can run Pootle like an internet server and run a local copy on an intranet. Pootle has a user friendly interface which ensures better quality and easier translation of projects. Users can log into the Pootle and create their own projects under any language, and they can also add or retrieve any language from any project or any project from any language. Although Pootle has many advantages, it also has its drawbacks, and one of the biggest drawbacks of Pootle is that whatever translation is …


Mobile Search Engine Using Clustering And Query Expansion, Huy Nguyen Jan 2010

Mobile Search Engine Using Clustering And Query Expansion, Huy Nguyen

Master's Projects

Internet content is growing exponentially and searching for useful content is a tedious task that we all deal with today. Mobile phones lack of screen space and limited interaction methods makes traditional search engine interface very inefficient. As the use of mobile internet continues to grow there is a need for an effective search tool. I have created a mobile search engine that uses clustering and query expansion to find relevant web pages efficiently. Clustering organizes web pages into groups that reflect different components of a query topic. Users can ignore clusters that they find irrelevant so they are not …


Reliable Broadcasting In Vanet, Pat Jangyodsuk Jan 2010

Reliable Broadcasting In Vanet, Pat Jangyodsuk

Master's Projects

Vehicular Adhoc NETwork (VANET) is a rapid growing wireless ad-hoc network model where the vehicles play the nodes role in a network. Major application of VANET including hazard warning application requires effective broadcast mechanism. Typically, selection of the next relaying hop is the major problem in VANET broadcasting. To get the smallest propagational delay, the number of relaying hops must be minimize. Meanwhile, the transmission reliability must also be preserved. Both of these two constrains must be taken into consideration. However, these two aspects often collide to each other since increasing one of them always result in decreasing of another. …


Genbank, Dennis A. Benson, Ilene Karasch-Mizrachi, David J. Lipman, James Ostell, Eric W. Sayers Jan 2010

Genbank, Dennis A. Benson, Ilene Karasch-Mizrachi, David J. Lipman, James Ostell, Eric W. Sayers

Harold W. Manter Laboratory of Parasitology: Library Materials

GenBank(R) is a comprehensive database that contains publicly available nucleotide sequences for more than 380,000 organisms named at the genus level or lower, obtained primarily through submissions from individual laboratories and batch submissions from large-scale sequencing projects, including whole genome shotgun (WGS) and environmental sampling projects. Most submissions are made using the web-based BankIt or standalone Sequin programs, and accession numbers are assigned by GenBank staff upon receipt. Daily data exchange with the European Nucleotide Archive (ENA) and the DNA Data Bank of Japan (DDBJ) ensures worldwide coverage. GenBank is accessible through the NCBI Entrez retrieval system that integrates data …


A Novel Weighted-Graph-Based Grouping Algorithm For Metadata Prefetching, Peng Gu, Jun Wang, Yifeng Zhu, Hong Jiang, Pengju Shang Jan 2010

A Novel Weighted-Graph-Based Grouping Algorithm For Metadata Prefetching, Peng Gu, Jun Wang, Yifeng Zhu, Hong Jiang, Pengju Shang

School of Computing: Faculty Publications

Although data prefetching algorithms have been extensively studied for years, there is no counterpart research done for metadata access performance. Existing data prefetching algorithms, either lack of emphasis on group prefetching, or bearing a high level of computational complexity, do not work well with metadata prefetching cases. Therefore, an efficient, accurate, and distributed metadata-oriented prefetching scheme is critical to leverage the overall performance in large distributed storage systems. In this paper, we present a novel weighted-graph-based prefetching technique, built on both direct and indirect successor relationship, to reap performance benefit from prefetching specifically for clustered metadata servers, an arrangement envisioned …


Xlp: A Cross-Layer Protocol For Efficient Communication In Wireless Sensor Networks, Mehmet C. Vuran, Ian F. Akyildiz Jan 2010

Xlp: A Cross-Layer Protocol For Efficient Communication In Wireless Sensor Networks, Mehmet C. Vuran, Ian F. Akyildiz

School of Computing: Faculty Publications

Severe energy constraints of battery-powered sensor nodes necessitate energy-efficient communication in Wireless Sensor Networks (WSNs). However, the vast majority of the existing solutions is based on classical layered protocols approach, which leads to significant overhead. It is much more efficient to have a unified scheme which blends common protocol layer functionalities into a cross-layer module. In this paper, a cross layer protocol (XLP) is introduced, which achieves congestion control, routing, and medium access control in a cross-layer fashion. The design principle of XLP is based on the cross-layer concept of initiative determination, which enables receiver-based contention, initiative-based forwarding, local …


Linear Programming Models For Multi-Channel P2p Streaming Systems, Miao Wang, Lisong Xu, Byrav Ramamurthy Jan 2010

Linear Programming Models For Multi-Channel P2p Streaming Systems, Miao Wang, Lisong Xu, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

Most of the commercial P2P video streaming deployments support hundreds of channels and are referred to as multichannel systems. Measurement studies show that bandwidth resources of different channels are highly unbalanced and thus recent research studies have proposed various protocols to improve the streaming qualities for all channels by enabling cross-channel cooperation among multiple channels. However, there is no general framework for comparing existing and potential designs for multi-channel P2P systems. The goal of this paper is to establish tractable models for answering the fundamental question in multi-channel system designs: Under what circumstances, should a particular design be used to …


Spatio-Temporal Soil Moisture Measurement With Wireless Underground Sensor Networks, Xin Dong, Mehmet C. Vuran Jan 2010

Spatio-Temporal Soil Moisture Measurement With Wireless Underground Sensor Networks, Xin Dong, Mehmet C. Vuran

School of Computing: Conference and Workshop Papers

In this paper, the estimation distortion of distributed soil moisture measurement using Wireless Underground Sensor Networks (WUSNs) is investigated. The main focus of this paper is to analyze the impact of the environment and network parameters on the estimation distortion of the soil moisture.More specifically, the effects of rainfall, soil porosity, and vegetation root zone are investigated by exploiting a rainfall model, in addition to the effects of sampling rate, network topology, and measurement signal noise ratio. Spatio-temporal correlation is characterized to develop a measurement distortion model with respect to these factors. The evaluations reveal that with porous soil and …


A First Practical Algorithm For High Levels Of Relational Consistency, Shant Karakashian, Robert J. Woodward, Christopher Reeson, Berthe Y. Choueiry, Christian Bessiere Jan 2010

A First Practical Algorithm For High Levels Of Relational Consistency, Shant Karakashian, Robert J. Woodward, Christopher Reeson, Berthe Y. Choueiry, Christian Bessiere

School of Computing: Conference and Workshop Papers

Consistency properties and algorithms for achieving them are at the heart of the success of Constraint Programming. In this paper, we study the relational consistency property R(*,m)C, which is equivalent to m-wise consistency proposed in relational databases. We also define wR(*,m)C, a weaker variant of this property. We propose an algorithm for enforcing these properties on a Constraint Satisfaction Problem by tightening the existing relations and without introducing new ones. We empirically show that wR(*,m)C solves in a backtrackfree manner all the instances of some CSP benchmark classes, thus hinting at the tractability …


A Partial Taxonomy Of Substitutability And Interchangeability, Shant Karakashian, Robert J. Woodward, Berthe Y. Choueiry, Steven D. Prestwich, Eugene C. Freuder Jan 2010

A Partial Taxonomy Of Substitutability And Interchangeability, Shant Karakashian, Robert J. Woodward, Berthe Y. Choueiry, Steven D. Prestwich, Eugene C. Freuder

School of Computing: Conference and Workshop Papers

Substitutability, interchangeability and related concepts in Constraint Programming were introduced approximately twenty years ago and have given rise to considerable subsequent research. We survey this work, classify, and relate the different concepts, and indicate directions for future work, in particular with respect to making connections with research into symmetry breaking. This paper is a condensed version of a larger work in progress.


Mechanical Sensorless Maximum Power Tracking Control For Direct-Drive Pmsg Wind Turbines, Xu Yang, Xiang Gong, Wei Qiao Jan 2010

Mechanical Sensorless Maximum Power Tracking Control For Direct-Drive Pmsg Wind Turbines, Xu Yang, Xiang Gong, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Wind turbine generators (WTGs) are usually equipped with mechanical sensors to measure wind speed and rotor position for system control, monitoring, and protection. The use of mechanical sensors increases the cost and hardware complexity and reduces the reliability of the WTG systems. This paper proposes a mechanical sensorless maximum power tracking control for wind turbines directly driving permanent magnetic synchronous generators (PMSGs). In the proposed algorithm, the PMSG rotor position is estimated from the measured stator voltages and currents by using a sliding mode observer (SMO). The wind turbine shaft speed is estimated from the PMSG back electromotive force (EMF) …


Wikipedia2onto: Building Concept Ontology Automatically, Experimenting With Web Image Retrieval, Huan Wang, Xing Jiang, Liang-Tien Chia, Ah-Hwee Tan Jan 2010

Wikipedia2onto: Building Concept Ontology Automatically, Experimenting With Web Image Retrieval, Huan Wang, Xing Jiang, Liang-Tien Chia, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Given its effectiveness to better understand data, ontology has been used in various domains including artificial intelligence, biomedical informatics and library science. What we have tried to promote is the use of ontology to better understand media (in particular, images) on the World Wide Web. This paper describes our preliminary attempt to construct a large-scale multi-modality ontology, called AutoMMOnto, for web image classification. Particularly, to enable the automation of text ontology construction, we take advantage of both structural and content features of Wikipedia and formalize real world objects in terms of concepts and relationships. For visual part, we train classifiers …


Using Python To Program Lego Mindstorms Robots: The Pynxc Project, Brian S. Blais Jan 2010

Using Python To Program Lego Mindstorms Robots: The Pynxc Project, Brian S. Blais

Science and Technology Department Faculty Journal Articles

LEGO MINDSTORMS® NXT (Lego Group, 2006) is a perfect platform for introducing programming concepts, and is generally targeted toward children from age 8-14. The language which ships with the MINDSTORMS®, called NXTg, is a graphical language based on LabVIEW (Jeff Kodosky, 2010). Although there is much value in graphical languages, such as LabVIEW, a text-based alternative can be targeted at an older audiences and serve as part of a more general introduction to modern computing. Other languages, such as NXC (Not Exactly C) (Hansen, 2010) and PbLua (Hempel, 2010), fit this description. Here we introduce PyNXC, a subset of the …


Vowel Recognition From Continuous Articulatory Movements For Speaker-Dependent Applications, Jun Wang, Jordan R. Green, Ashok Samal, Tom D. Carrell Jan 2010

Vowel Recognition From Continuous Articulatory Movements For Speaker-Dependent Applications, Jun Wang, Jordan R. Green, Ashok Samal, Tom D. Carrell

Department of Special Education and Communication Disorders: Faculty Publications

A novel approach was developed to recognize vowels from continuous tongue and lip movements. Vowels were classified based on movement patterns (rather than on derived articulatory features, e.g., lip opening) using a machine learning approach. Recognition accuracy on a single-speaker dataset was 94.02% with a very short latency. Recognition accuracy was better for high vowels than for low vowels. This finding parallels previous empirical findings on tongue movements during vowels. The recognition algorithm was then used to drive an articulation-to-acoustics synthesizer. The synthesizer recognizes vowels from continuous input stream of tongue and lip movements and plays the corresponding sound samples …


An Empirical Analysis Of Mobile Voice Service And Sms: A Structural Model, Youngsoo Kim, Rahul Telang, William B. Vogt, Ramayya Krishnan Jan 2010

An Empirical Analysis Of Mobile Voice Service And Sms: A Structural Model, Youngsoo Kim, Rahul Telang, William B. Vogt, Ramayya Krishnan

Research Collection School Of Computing and Information Systems

In addition to the wireless telephony boom, a similar exponentially increasing trend in wireless data service—for example, short message service (SMS)—is visible as technology advances. We develop a structural model to examine user demand for voice service and SMS. Specifically, we measure the own- and cross-price elasticities of these services. The cross-price elasticity is of significant importance because marketing activities are critically influenced by whether the goods are substitutes or complements. The research context poses significant econometric challenges due to three-part tariffs and sequential discrete plan choice and continuous quantity choice decisions. Using detailed individual consumption data of more than …


Mining Antagonistic Communities From Social Networks, Kuan Zhang Jan 2010

Mining Antagonistic Communities From Social Networks, Kuan Zhang

Dissertations and Theses Collection (Open Access)

In this thesis, we examine the problem of mining antagonistic communities from social networks. In social networks, people with opposite opinions normally behave differently and form sub-communities each of which containing people sharing some common behaviors. In one scenario, people with opposite opinions show differences in their views on a set of items. Another scenario is people explicitly expressing whom they agree with, like or trust as well as whom they disagree with, dislike or distrust. We defined the indirect and direct antagonistic groups based on the two scenarios. We have developed algorithms to mine the two types of antagonistic …


Security And Performance Analysis For Rfid Protocols, Bing Liang Jan 2010

Security And Performance Analysis For Rfid Protocols, Bing Liang

Dissertations and Theses Collection (Open Access)

Radio Frequency Identification (RFID) is an advanced object identification technology that has already been applied in various industries. However, the insecure nature of the communication channel between readers and tags makes RFID systems vulnerable to various kinds of attacks. In recent years, many new methods have been proposed to improve the security of RFID systems, such as disabling tags, agent management and establishing cryptographic protocols. Among them, we focus on the last approach, which is more economic and convenient in certain cases. The first part of our work is to categorize typical existing RFID protocols according to their security levels. …


Acceleration Of Monte Carlo Value At Risk Estimation Using Graphics Processing Unit (Gpu), Wei Wu Jan 2010

Acceleration Of Monte Carlo Value At Risk Estimation Using Graphics Processing Unit (Gpu), Wei Wu

Dissertations and Theses

"Value at Risk (VaR) is one of the most popular tools used to estimate the exposure to market risks, and it measures the worst expected loss at a given confidence level. Monte Carlo simulation is one of the best methods to calculate VaR and it is widely used in financial industry. Unfortunately, it is time consuming especially when the simulated samples and the number of assets in a portfolio are very large. The graphics processing unit (GPU) is a specialized multiprocessor which has highly parallel structure supporting more effective than general-purpose CPUs for a range of complex algorithms. In this …


Scalable Event Tracking On High-End Parallel Systems, Kathryn Marie Mohror Jan 2010

Scalable Event Tracking On High-End Parallel Systems, Kathryn Marie Mohror

Dissertations and Theses

Accurate performance analysis of high end systems requires event-based traces to correctly identify the root cause of a number of the complex performance problems that arise on these highly parallel systems. These high-end architectures contain tens to hundreds of thousands of processors, pushing application scalability challenges to new heights. Unfortunately, the collection of event-based data presents scalability challenges itself: the large volume of collected data increases tool overhead, and results in data files that are difficult to store and analyze. Our solution to these problems is a new measurement technique called trace profiling that collects the information needed to diagnose …


High Accuracy Multiscale Multigrid Computation For Partial Differential Equations, Yin Wang Jan 2010

High Accuracy Multiscale Multigrid Computation For Partial Differential Equations, Yin Wang

University of Kentucky Doctoral Dissertations

Scientific computing and computer simulation play an increasingly important role in scientific investigation and engineering designs, supplementing traditional experiments, such as in automotive crash studies, global climate change, ocean modeling, medical imaging, and nuclear weapons. The numerical simulation is much cheaper than experimentation for these application areas and it can be used as the third way of science discovery beyond the experimental and theoretical analysis. However, the increasing demand of high resolution solutions of the Partial Differential Equations (PDEs) with less computational time has increased the importance for researchers and engineers to come up with efficient and scalable computational techniques …