Computer Sciences Commons^™

A Unified Framework For Solving Multiagent Task Assignment Problems, Kevin Cousin

Theses and Dissertations

Multiagent task assignment problem descriptors do not fully represent the complex interactions in a multiagent domain, and algorithmic solutions vary widely depending on how the domain is represented. This issue is compounded as related research fields contain descriptors that similarly describe multiagent task assignment problems, including complex domain interactions, but generally do not provide the mechanisms needed to solve the multiagent aspect of task assignment. This research presents a unified approach to representing and solving the multiagent task assignment problem for complex problem domains. Ideas central to multiagent task allocation, project scheduling, constraint satisfaction, and coalition formation are combined to …

Settling For Limited Privacy: How Much Does It Help?, Anna M. Shubina

Dartmouth College Ph.D Dissertations

This thesis explores practical and theoretical aspects of several privacy-providing technologies, including tools for anonymous web-browsing, verifiable electronic voting schemes, and private information retrieval from databases. State-of-art privacy-providing schemes are frequently impractical for implementational reasons or for sheer information-theoretical reasons due to the amount of information that needs to be transmitted. We have been researching the question of whether relaxing the requirements on such schemes, in particular settling for imperfect but sufficient in real-world situations privacy, as opposed to perfect privacy, may be helpful in producing more practical or more efficient schemes. This thesis presents three results. The first result …

A Hybrid Multi-Robot Control Architecture, Daylond J. Hooper

Theses and Dissertations

Multi-robot systems provide system redundancy and enhanced capability versus single robot systems. Implementations of these systems are varied, each with specific design approaches geared towards an application domain. Some traditional single robot control architectures have been expanded for multi-robot systems, but these expansions predominantly focus on the addition of communication capabilities. Both design approaches are application specific and limit the generalizability of the system. This work presents a redesign of a common single robot architecture in order to provide a more sophisticated multi-robot system. The single robot architecture chosen for application is the Three Layer Architecture (TLA). The primary strength …

A Middle-Ware Level Client Cache For A High Performance Computing I/O Simulator, Michael Bassily

All Theses

This thesis describes the design and run time analysis of the system level middle-ware cache for Hecios. Hecios is a high performance cluster I/O simulator. With Hecios, we provide a simulation environment that accurately captures the performance characteristics of all the components in a clusterwide parallel file system. Hecios was specifically modeled after PVFS2. It was designed to be extensible and to easily allow for various component modules to be easily replaced by those that model other system types. Built around the OMNeT++ simulation package, Hecios' inner-cluster communication module is easily adaptable to any TCP/IP based protocol and all standard …

Rendering Principal Direction Contour Lines With Oriented Textures, Kelly Gallagher

All Theses

In this paper we explore the use of contour lines in computer graphics as a means of conveying shape to the end-user. Contour lines provide an alternative to traditional realistic rendering styles and may even provide a more appropriate visualization for certain situations. For our images, contour line orientation is established in accordance with principal curvature directions.
We present a method for rendering a texture, oriented in the principal curvature direction, across a traditionally-modeled geometric surface that effectively forms suggestive contour lines to enhance the visualization of that surface. We further extend the method to create animated contour textures, wherein …

Hybrid Image/Model Based Gaze-Contingent Rendering, Hunter Murphy

All Dissertations

A non-isotropic hybrid image/model based gaze-contingent rendering technique utilizing ray casting on a GPU is discussed. Empirical evidence derived from human subject experiments indicates an inverse relationship between a peripherally degraded scene's high-resolution inset size and mean search time, a trend consistent with existing image-based and model-based techniques. In addition, the data suggest that maintaining a target's silhouette edges decreases search times when compared to targets with degraded edges. Benefits of the hybrid technique include simplicity of design and parallelizability, both conducive to GPU implementation.

Distributed Web Service Coordination For Collaboration Applications And Biological Workflows, Janaka Lalith Balasooriya

Computer Science Dissertations

In this dissertation work, we have investigated the main research thrust of decentralized coordination of workflows over web services. To address distributed workflow coordination, first we have developed “Web Coordination Bonds” as a capable set of dependency modeling primitives that enable each web service to manage its own dependencies. Web bond primitives are as powerful as extended Petri nets and have sufficient modeling and expressive capabilities to model workflow dependencies. We have designed and prototyped our “Web Service Coordination Management Middleware” (WSCMM) system that enhances current web services infrastructure to accommodate web bond enabled web services. Finally, based on core …

Web Based Resource Management For Multi-Tiered Web Applications, Bryce Daniel Ott

Theses and Dissertations

The currently emerging trend of building more complex web applications to solve increasingly more involved software problems has led to the the need for a more automated and practical means for deploying resources required by these advanced web applications. As web based applications become more complex and involve more developers, greater system redundancy, and a larger number of components, traditional means of resource deployment become painfully inadequate as they fail to scale sufficiently. The purpose of this research is to provide evidence that a more sound and scalable test and deployment process can be employed and that many of the …

Goal-Oriented Job Scheduling For Parallel Computer Systems, Sangsuree Vasupongayya

Dissertations and Theses

System administrators for parallel computers face many difficulties when managing job scheduling systems. First, current production job schedulers use many parameters, which seem flexible but it is highly challenging to configure and tune these parameters. Second, fair share is an important scheduling goal, but it is not clear what kind of fair share can be expected under current schedulers and how fair share impacts scheduling performance. Third, several job runtime prediction methods were proposed to improve inaccurate user-estimated runtimes, but these methods could under-estimate runtimes by a large amount and it is not clear whether they are practical for use …

Improving Scalability And Usability Of Parallel Runtime Environments For High Availability And High Performance Systems, Thara Angskun

Doctoral Dissertations

The number of processors embedded in high performance computing platforms is growing daily to solve larger and more complex problems. Hence, parallel runtime environments have to support and adapt to the underlying platforms that require scalability and fault management in more and more dynamic environments. This dissertation aims to analyze, understand and improve the state of the art mechanisms for managing highly dynamic, large scale applications.

This dissertation demonstrates that the use of new scalable and fault-tolerant topologies, combined with rerouting techniques, builds parallel runtime environments, which are able to efficiently and reliably deliver sets of information to a large …

Statistical And Machine Learning Techniques Applied To Algorithm Selection For Solving Sparse Linear Systems, Erika Fuentes

Doctoral Dissertations

There are many applications and problems in science and engineering that require large-scale numerical simulations and computations. The issue of choosing an appropriate method to solve these problems is very common, however it is not a trivial one, principally because this decision is most of the times too hard for humans to make, or certain degree of expertise and knowledge in the particular discipline, or in mathematics, are required. Thus, the development of a methodology that can facilitate or automate this process and helps to understand the problem, would be of great interest and help. The proposal is to utilize …

Towards Automatic And Adaptive Optimizations Of Mpi Collective Operations, Jelena Pjesivac-Grbovic

Doctoral Dissertations

Message passing is one of the most commonly used paradigms of parallel programming. Message Passing Interface, MPI, is a standard used in scientific and high-performance computing. Collective operations are a subset of MPI standard that deals with processes synchronization, data exchange and computation among a group of processes. The collective operations are commonly used and can be application performance bottleneck. The performance of collective operations depends on many factors, some of which are the input parameters (e.g., communicator and message size); system characteristics (e.g., interconnect type); the application computation and communication pattern; and internal algorithm parameters (e.g., internal segment size). …

Limitations Of Ieee 802.15.4 Based Wireless Mesh Networks For Wireless Localization, William Anthony Wallace

Computer Science and Engineering Theses

It is highly desirable to create rapidly and inexpensively deployable mesh networks in certain scenarios. Consider the case of a large storage warehouse; workers are constantly moving in the area and not only do they need to send data periodically but their location needs to be tracked as well. Setting up such network can be accomplished with the IEEE 802.15.4 standard, but a mesh network must be created. There would need to be stationary 802.15.4 nodes that join together to form a backbone infrastructure. This backbone infrastructure (mesh network) would allow the workers, using mobile 802.15.4 nodes, to transmit their …

Stochastic Models For In-Silico Event-Based Biological Network Simulation, Preetam Ghosh

Computer Science and Engineering Dissertations

The multi-scale biological system model is a new research direction to capture the dynamic measurements of complex biological systems. The current statistical thermodynamic models can not scale to this challenge due to the explosion of state-spaces of the system, where a biological organ may have billions of cells, each with millions of molecule types and each type may have a few million molecules. We seek to propose a phenomenological theory that will require a smaller number of state variables to address this multi-scaling problem. Discrete Markov statistical process is used to understand the system dynamics in the networking community for …

A Discrete Event Based Stochastic Simulation Approach For Studying The Dynamics Of Biological Networks, Samik Ghosh

Computer Science and Engineering Dissertations

With increasing availability of data resources on the molecular parts of a living cell, biologists are focusing on holistic understanding of cellular mechanisms and the emergent dynamics arising out of their complex interactions. Comprehending the fine-grained signal specificity, gene regulation and feedback mechanisms of molecular interactions at a network level forms a central theme of systems biology. With the speed and sophistication of computational methods, in silico modeling and simulation techniques have become a powerful tool for biologists challenged with understanding the system complexity of biological networks. Numerical simulation of classical chemical kinetics (CCK), agent-based simulations of biological processes, and …

Cxlengine - A Comprehensive Xml Loosely Structured Search Engine, Indhu Krishna Sivaramakrishnan

Computer Science and Engineering Theses

XML keyword search has been a widely researched area. [15] has proposed an XML semantic search engine called OOXSearch, which answers loosely structured queries. The framework of OOXSearch takes into account the semantic relationship between nodes based on their contexts. The context of a node is determined by its parent node. The label "name", for example, could mean the name of a book and could also mean the name of the book's author. If we try to consider the relationship between these two nodes without considering their parent nodes, we would be drawing the incorrect conclusion that these two nodes …

Panda Monitoring - A System To Monitor High Performance Computing For The Atlas Experiment-Design, Development,Implementation And Deployment, Prem A. Thilagar

Computer Science and Engineering Theses

Grid resources are gaining wide importance in the wake of experiments such as ATLAS aiding in a bigger goal to understand the complexities of nature. The need for a good monitoring system is realized as grid resources are being implemented widely. This work is an analysis of the existing monitoring system of the Panda which is a grid middleware for the ATLAS experiment running in CERN. The thesis aims at identifying the key bottlenecks of the current monitor and speaks about the implementation of a new monitor for the same .The new monitor which is being designed with scalability and …

Learning Video Preferences Using Visual Features And Closed Captions, Darin Brezeale

Computer Science and Engineering Dissertations

Viewers of video now have more choices than ever. As the number of choices increases, the task of searching through these choices to locate video of interest is becoming more difficult. Current methods for learning a viewer's preferences in order to automate the search process rely either on video having content descriptions or on having been rated by other viewers identified as being similar. However, much video exists that does not meet these requirements. To address this need, we use hidden Markov models to learn the preferences of a viewer by combining visual features and closed captions. We validate our …

Distributed Predictive Health Monitoring, Jorge David Herrera Gonzalez

Computer Science and Engineering Theses

According to the National Center for Health Statistics the major causes of death in the US are (per year) heart diseases with 654 thousand cases, followed by cancer with 550 thousand cases and stroke with 150 thousand cases. In this project we propose, design, implement and test a prototype of a system that promises to improve the level of detection and prediction of several diseases and improves the quality of life of patients by utilizing non-invasive wireless medical sensors. This system is composed of a set of wireless medical sensors, a nearby (close-proximity) PDA (personal digital accessory) or cell phone …

Subrosa: An Experimental Platform For Studying Timing Analysis Of Real Time Anonymity Systems, Hatim Asger Daginawala

Computer Science and Engineering Theses

Timing analysis poses a significant challenge for the mix based anonymous systems that wish to support low-latency applications like web browsing, instant messaging and Voice over IP (VOIP). Research in this area so far has been done through simulations on ad hoc simulators or non practical local area networks. We developed SubRosa, an experimental platform for studying timing analysis of real time anonymity systems to facilitate the study of Tor like low-latency anonymous systems. We present results of experiments on a real distributed network test bed PlanetLab, where we studied timing analysis attacks and some of the defenses to protect …

Combining Geospatial And Temporal Ontologies, Kripa Joshi

Electronic Theses and Dissertations

Publicly available ontologies are growing in number at present. These ontologies describe entities in a domain and the relations among these entities. This thesis describes a method to automatically combine a pair of orthogonal ontologies using cross products. A geospatial ontology and a temporal ontology are combined in this work. Computing the cross product of the geospatial and the temporal ontologies gives a complete set of pairwise combination of terms from the two ontologies. This method offers researchers the benefit of using ontologies that are already existing and available rather than building new ontologies for areas outside their scope of …

Linking Moving Object Databases With Ontologies, Kraig King

Electronic Theses and Dissertations

This work investigates the supporting role of ontologies for supplementing the information contained in moving object databases. Details of the spatial representation as well as the sensed location of moving objects are frequently stored within a database schema. However, this knowledge lacks the semantic detail necessary for reasoning about characteristics that are specific to each object. Ontologies contribute semantic descriptions for moving objects and provide the foundation for discovering similarities between object types. These similarities can be drawn upon to extract additional details about the objects around us. The primary focus of the research is a framework for linking ontologies …

Malicious Mobile Code Related Experiments With An Extensible Network Simulator, Attila Ondi

Theses and Dissertations

The automated spread of worms such as Code-Red, SQL/Slammer, and Nimda have caused costly problems to computers connected to the Internet. Even users whose machines were not vulnerable to these threats suffered a loss of productivity and experienced great frustration as connectivity and network traffic were negatively impacted during outbreaks. Although the number of new worm attacks reported in the media seems to be declining, it is vital that researchers study the effects of malicious code on the global network to understand how to defend against future threats. The choice of system for studying the spread of worms and viruses …

Route Validation Using Radio Frequency Identification, William T. Watson

Theses and Dissertations

In recent years, radio frequency identification (RFID) has been proposed and implemented in a variety of applications where tracking objects, animals or people is desirable. This paper proposes a novel approach to the application of RFID tech- nology in those applications where it is possible to validate a person or an object's passive contact with a given or arbitrary set of fixed points along a predefined route. The notable departure from the typical application of RFID technology is that in this scheme, the transponders are permanently installed while the interrogator is affixed to a person or object that travels the …

Rss Management: An Rss Reader To Manage Rss Feeds That Efficiently And Effectively Pulls And Filters Feeds With Minimal Bandwidth Consumption, Brian Cooper

Theses and Dissertations

In the early 2000s, RSS (Really Simple Syndication) was launched into cyber space and rapidly gained fame by existing as the underlying technology that fueled millions of web logs (blogs). Soon RSS feeds appeared for news, multimedia podcasting, and many other types of information on the Internet. RSS introduced a new way to syndicate information that allowed anyone interested to subscribe to published content and pull the information to an aggregator, (RSS reader application), at their discretion. RSS made it simple for people to keep up with online content without having to continuously check websites for new content. This new …

A Direct Algorithm For The K-Nearest-Neighbor Classifier Via Local Warping Of The Distance Metric, Tohkoon Neo

Theses and Dissertations

The k-nearest neighbor (k-NN) pattern classifier is a simple yet effective learner. However, it has a few drawbacks, one of which is the large model size. There are a number of algorithms that are able to condense the model size of the k-NN classifier at the expense of accuracy. Boosting is therefore desirable for increasing the accuracy of these condensed models. Unfortunately, there does not exist a boosting algorithm that works well with k-NN directly. We present a direct boosting algorithm for the k-NN classifier that creates an ensemble of models with locally modified distance weighting. An empirical study conducted …

Peer-To-Peer Distributed Syd Directory Synchronization In A Proximity-Based Environment, Sunetri Priyanka Dasari

Computer Science Theses

Distributed directory services are an evolving paradigm in the distributed computing arena. They are a shift from the centralized directory that causes delay and does not scale well to widespread peer-to-peer networks. With networking becoming more pervasive, there is a need to integrate the heterogeneity of device, data and network with the applications that are built on them. SyD or System on Mobile Devices is a middleware that is being used to implement such a distributed directory service. To provide a persistent global view of data, we serialize and synchronize the distributed directories. The SyD APIs provide a high-level environment …

Contour Based 3d Biological Image Reconstruction And Partial Retrieval, Yong Li

Computer Science Dissertations

Image segmentation is one of the most difficult tasks in image processing. Segmentation algorithms are generally based on searching a region where pixels share similar gray level intensity and satisfy a set of defined criteria. However, the segmented region cannot be used directly for partial image retrieval. In this dissertation, a Contour Based Image Structure (CBIS) model is introduced. In this model, images are divided into several objects defined by their bounding contours. The bounding contour structure allows individual object extraction, and partial object matching and retrieval from a standard CBIS image structure. The CBIS model allows the representation of …

Ieee 802.15.4 Mac Protocol Study And Improvement, Liang Cheng

Computer Science Dissertations

IEEE 802.15.4 is a standard used for low rate personal area networks (PANs). It offers device level connectivity in applications with limited ower and relaxed throughput requirements. Devices with IEEE 802.15.4 technology can be used in many potential applications, such as home networking, industry/environments monitoring, healthcare equipments, etc, due to its extremely low power features. Although the superframe beacons play the key role in synchronizing channel access in IEEE 802.15.4, they are sources for energy inefficiency. This research focuses on exploring how to optimize the beacons, and designing novel schemes to distribute the information that are supposed to be delivered …

A Contextualized Web-Based Learning Environments For Devs Models, Inthira Srivrunyoo

Computer Science Theses

With the advance in applying technology in education, the traditional lecture-driven teaching style is gradually replaced by a more active teaching style where the students play a more active rule in the learning process. In this paper we introduce a new initiative to provide a suite of online tools for learning DEVS model. The uniqueness of this tutorial project is the integration of information technology and multimedia into education through the development of an interactive tutorial and the characteristic of contextualized learning. The tutorial teaches students about the basic aspects of discrete event system and simulation. The interactive tutorial fully …