Department: College of Arts and Sciences / Department of Computer Science ![[clear]](close-x.png "Remove this limiter")
87 matches in the database.
These are records: 1 - 30.
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1.
Alali, Abdulkareem.
AN EMPIRICAL CHARACTERIZATION OF COMMITS IN SOFTWARE REPOSITORIES.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► The thesis examines the version histories of nine open source software systems…
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▼ The thesis examines the version histories of nine open source software systems to uncover trends and characteristics of how developers commit source code to version control systems (e.g., subversion, CVS). The goal is to characterize what a typical or normal commit looks like with respect to the number of files, number of lines, and number of hunks committed together. Surprisingly, there have been no in depth empirical studies of the characteristics of commits and this work represents one of the first studies to present trends across a number of systems. The results of the three characteristics are presented and the commits are categorized from extra small to extra large. The findings show that approximately 75% of commits are quite small for the systems examined along all three characteristics. Additionally, the commit messages are examined along with the characteristics. The most common words are extracted from the commit messages and correlated with the size categories of the commits. It is observed that sized categories can be indicative of the types of maintenance activities being performed.
Advisors/Committee Members: Maletic, Jonathan.
Subjects: Computer science
Keywords: version control system; subversion; typical; commit; hunks; Software Repositories
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2.
Al-Haj Baddar, Sherenaz Waleed.
Finding Better Sorting Networks.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2009, Kent State University
► Sorting networks are cost-effective multistage interconnection networks with sorting capabilities. AKS Sorting…
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▼ Sorting networks are cost-effective multistage interconnection networks with sorting capabilities. AKS Sorting networks sort N keys in C(logN) steps, but the constant C is so high as to render these networks impractical. The fastest Sorting networks designed so far use merge-sorting and sort N keys in O((logN)(logN)) steps. A network that sorts 16 keys in 9 steps was discovered by Van Voorhis. This network is faster than the 10-step merge-sorting network for 16 keys. This suggests that networks that are faster than merge-sorting networks can be designed. It is necessary to bridge the gap between the optimal impractical solutions and the practical solutions. This research aims at achieving this goal via finding a technique for designing faster Sorting networks, i.e. networks that require fewer steps than the corresponding merge-sorting networks. A zero/one case is a sequence of N binary keys. Using zero/one cases to help design Sorting networks, is advantageous since it simplifies the sorting task, and helps track the progress of sorting. To help synthesize and analyze Sorting networks, Batcher developed the software tool Sortnet, which utilizes zero/one cases. With the help of Sortnet, a three-phase technique for designing Sorting networks that are faster than the merge-sorting networks was developed. The technique can also be used to design faster sorting programs in parallel processors. This technique is illustrated with two network designs that are faster than the corresponding merge-sorting designs: an 18-key network using only 11 steps and a 22-key network using only 12 steps.
Advisors/Committee Members: Batcher, Dr. Kenneth.
Subjects: Computer science
Keywords: Sorting Networks; Parallel Sorting; Zero/one cases; Partial Ordering
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3.
AL-Maksousy, Hassan Hadi Latheeth.
Performance Analysis of Multi-hop Wireless Networks.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2012, Kent State University
► Multi-hop wireless networks have been extensively studied and are widely deployed for…
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▼ Multi-hop wireless networks have been extensively studied and are widely deployed for various networks. These networks include mobile Ad-hoc networks, sensor networks, mesh networks, space communication networks and delay-tolerance networks. In multi-hop wireless networks the end-to-end performance, in terms of throughput and delay, degrades exponentially with hop counts. Several factors contribute to this degradation including network topology, node distance, media access control protocol, application and the source and aggregate traffic characteristics. In this thesis we studied the impact of various factors that determine the performance of an end-to-end connection for various applications in multi-hop wireless networks. We have developed various simulation models to study the dynamics of the above mentioned factors for different media access control including IEEE 802.11, IEEE 802.11e, IEEE 802.11s and TDMA under different traffic source conditions, such as constant bit rate, file transfer protocol and general traffic. Our study shows that multi-hop networks have significant limitations for delay-sensitive traffic and significant limitation in quality of service provisioning.
Advisors/Committee Members: Peyravi, Hassan.
Subjects: Computer Science
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4.
Alomari, Hakam W.
Supporting Software Engineering Via Lightweight Forward Static Slicing.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2012, Kent State University
► The dissertation introduces an efficient and highly scalable lightweight forward static slicing…
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▼ The dissertation introduces an efficient and highly scalable lightweight forward static slicing approach. The implementation of the approach is applied, in novel ways, to large-scale software systems. Program slicing is a commonly used approach for understanding and detecting the impact of changes to software. That is, given a variable and the location of that variable in a program, the other parts of the program that are affected by this variable can be determined. The approach has been used successfully for many years for various maintenance tasks. For example, slicing was used to help address the Y2K problem by identifying parts of a program that could be impacted by changes on date fields. However, current approaches to program slicing are based on computing the program dependency graph (PDG) and computing the PDG can be very computationally expensive and scales poorly. Additionally, current approaches assume the system being examined can be completely compiled. This is not always the case when a system is undergoing maintenance, in particular during a platform change. The approach taken here does not compute the complete PDG, instead it determines program dependencies locally as needed when computing a slice for a give variable. Due to the efficient nature of the approach it is used to address a number of applications and problems that, in practice cannot be (or are extremely costly) to address with current heavyweight slicing approaches. The dissertation addresses the following specific problems in novel ways. The scalability of the approach is demonstrated for large-scale systems, specifically all the slices for 17 years of versions of the Linux kernel (over 900 versions) is performed. The tool is highly scalable and can generate the slices for all variables of the Linux kernel in less than 15 minutes. How slices change over the history of software system is investigated and slice-based software metrics are introduced that reflect maintenance effort. These metrics are extracted directly from the source code without any other metadata. An approach to estimate the maintenance effort for open-source systems using the new slice-based metrics is also developed. Three different granularities of slice sizes are analyzed. Lastly, different maintenance activities performed during the lifetime of large software systems are modeled with the objective to provide empirical support for Lehman’s laws of software evolution.
Advisors/Committee Members: Maletic, Jonathan.
Subjects: Computer Science
Keywords: Program slicing; software maintenance; impact analysis; software metrics; effort estimation
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5.
Alsakran, Jamal.
Supporting Interactive Visual Analytics for High Dimensional Data Exploration.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2012, Kent State University
► High dimensional data is everywhere in our life and in all sectors…
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▼ High dimensional data is everywhere in our life and in all sectors of our society: text, image, audio, video, and other. Analyzing such rich data and understanding its behavioral and structural aspects is a fruitful process that will provide us with valuable information and insights, and eventually promote the decision making. Visual analytics significantly enhances the analysis of high dimensional data. It elegantly integrates computational tools with interactive techniques and visual representations to enable human-information discourse. Nevertheless, the high dimensionality and large scale have posed critical challenges for the data analysis and exploration. In this dissertation, we propose a set of visual analytical approaches to promote the understanding of the data. Essentially, the approaches aim to advance the visual analytical capabilities in clutter reduction, dimension management, categorical, and stream data visualization. We propose density distribution map and tile-based parallel coordinates to allow users to investigate the relationship between dimensions. The tools are crafted to reduce visual clutter and highlight data patterns, trends, and anomalies. In addition, they are equipped with interactive features to manipulate the visualization results. An extensive case study in the performance of mutual fund is provided to show the effectiveness of the proposed methods. Categorical data, which contains variables whose values comprise a set of discrete categories, is widely common. The discrete nature often confounds the direct application of existing multidimensional visualization techniques. We propose to use entropy-related measures to enhance the visualization of categorical data. The entropy information is employed to guide the ordering and filtering in parallel sets and scatter plot matrix visualizations. Furthermore, A novel TabularCluster visualization is proposed to depict cluster characteristics and leverage effective examination and comparison. An interactive visualization system, named STREAMIT, that enables users to explore text streams without a prior knowledge is proposed. STREAMIT supports interactive exploration with increased scalability: First, keyword importance is adjustable on-the-fly for desirable clustering effects from varying interests. Second, topic modeling is used to represent the documents with higher level semantic meanings. Third, document clusters are created on the 2D layout to promote better understanding. Case studies and real-world applications are presented to demonstrate the effectiveness of STREAMIT.
Advisors/Committee Members: Zhao, Ye.
Subjects: Computer Science
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6.
Al-shomrani, Saleh M.
A Web-based Distributed and Interoperable Tool for Sharing Mathematical Assessments and Supervising Online Tests.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► Investigated and reported in this dissertation is a modern Web-based Distributed Mathematics…
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▼ Investigated and reported in this dissertation is a modern Web-based Distributed Mathematics Assessment System (DMAS). The interdisciplinary work involves mathematics, computer science and education. As part of the Web-based Mathematics Education (WME) project, DMAS works well with WME for middle school mathematics education. But, like WME, DMAS is designed to work independently and at different education levels. The primary goal of research here is the design and implementation of a Web-based mathematics assessment system that is not only useful, practical, and powerful but also allows teachers everywhere to contribute to a distributed question bank that can grow quickly and be shared broadly. DMAS has undergone multiple pilot trials at Kimpton middle school and benefited greatly from collaboration with others in the WME project. At the core of DMAS is the Distributed Mathematics Assessment database (DMAD) that is designed to work as one distributed database while providing power, unity, and convenience at each participating school. DMAS features include: a test authoring tool for teachers, online taking of tests for students, grading and results administration, question diagnosis and dynamic linking to TLP materials, importing/exporting DMAS File Formats (DFF), mathematics answer checking, automatic question generation, and an XML language designed for question markup, the Mathematics Assessment Markup Language (MAML). DMAS supports many problem types, provides a search engine for assessment questions, and allows mathematical formulas/expressions as well as geometry drawings/graphs to be part of questions and answers. Furthermore, DMAS supports the use of test taking as a teaching method. A teacher can monitor all students from the teacher terminal in real-time and either verbally guide the whole class on certain points or interact privately with one or more students via a Teacher-Student Interaction Mechanism (TSIM) provided by DMAS. Questions in DMAS use a well-designed representation (encoding) allowing correct answers, rubrics, formulas, images, geometrical objects (SVG), and multimedia as well as interactive contents. Because DMAS has been designed in consultation with middle school teachers and education experts, the underline DMAS system design and framework is easy and flexible for future changes, requirements, expansions, and customizations. DMAS provides features to support real-life test giving such as loss of power to a laptop and retaking of tests. DMAS has also begun to investigate automatic grading of student answers by using well-defined Web-based answer checking services. DMAS is an independent Web system easily interfaced to any Web page through a well-defined API. DMAS is an open system involves Client-Side and Serve-Side programming and implemented with standard Web/Internet/Database technologies and protocols.
Advisors/Committee Members: Wang, Paul.
Subjects: Computer science; Mathematics education
Keywords: Mathematics education; Web-based Distributed and Interoperable Assessment Tool; Sharing Assessments; Mathematical Assessments; Supervising Online Tests
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7.
Amiruzzaman, Md.
STEGANOGRAPHIC COVERT COMMUNICATION CHANNELS AND THEIR DETECTION.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2011, Kent State University
► Covert channels facilitate the capability to transfer secret information between processes without…
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▼ Covert channels facilitate the capability to transfer secret information between processes without being detected. They are used for good intentions as well as bad intentions. The latter is used in computer security attacks. The former is used to transport secret data over a covert channel. Once a covert channel is established, it is important to protect it from intruders who intend to discover its transportation mechanisms. While cryptography allows plain visibility of encrypted data, steganography hides the existence of the data and the underlying communication channel. Statistical analysis of network packets (headers or payload) as well as communication channel characteristics can be used to reveal the existence of covert activities. For example, first-order statistical analysis can be used to detect the basic properties of certain covert channels. While there exist some level of protection against establishing a cover channel at lower layers, top layers and network applications are more vulnerable to be used to establish a cover channel. There are several applications that can be used to establish a covert channel. Among them JPEG images, commonly used across the Internet, are often utilized to establish a covert channel and transport hidden data. In this thesis, first, we provide a survey of the major steganographic algorithms and we introduce a new technique in which a set of concurrent covert channels can be established between a sender and multiple receivers. Each channel is protected by a separate key. Second, we introduce a new steganographic detection technique, based on statistical sequential analysis and process control, that detects a group of covert channels established over transmission of JPEG images. The technique performs better in terms of average run length when compared to the existing detection techniques.
Advisors/Committee Members: Peyravi, Hassan.
Subjects: Computer Science
Keywords: covert channel; steganography; detection
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8.
Asokan, Abhishek.
IMPACT OF OFFSHORING IN COMPUTER SCIENCE.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2006, Kent State University
► Offshoring is a term that has become prominent in today’s business and…
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▼ Offshoring is a term that has become prominent in today’s business and economic world. It’s not a new term for the global economy. The semi conductor and hardware industries in the 1970’s and the automobile industry in the 1980’s have seen earlier forms of offshoring. Later the manufacturing and production industry adopted this strategy and now almost all industries using IT and IT enabled services implement offshoring as a business strategy. So what is different between the early forms of offshoring and the current form of offshoring? We believe that early forms of offshoring affected only a specific industry whereas the present day offshoring potentially affects almost all industries and businesses. This is primarily because application of Information Technology has made businesses more manageable and more profitable than without IT. Thus almost all businesses are using IT and it follows that IT offshoring will affect almost all businesses and industries. Our thesis involves studying the impact of offshoring in the field of computer science. In particular, we examine the social and ethical implications of offshoring with relevance to IT.
Advisors/Committee Members: Melton, Austin.
Subjects: Computer Science
Keywords: Offshoring
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9.
Assareh, Amin.
OPTIMIZING DECISION TREE ENSEMBLES FOR GENE-GENE INTERACTION DETECTION.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2012, Kent State University
► In recent years, genome-wide association studies (GWAS) have been dedicated to unraveling…
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▼ In recent years, genome-wide association studies (GWAS) have been dedicated to unraveling the genetic etiology of complex diseases. It is widely accepted that most common diseases such as neurodegenerative diseases (e.g., Alzheimer's and Parkinson's diseases), cardiovascular diseases, various cancers, diabetes and osteoporosis are the results of multiple genes, their interactions, environmental factors, and gene-by-environment interactions and thus cannot be explained by a simple Mendelian inheritance model. Consequently, the study of dissecting gene-gene and/or gene-environment interactions involved in complex diseases/traits has become an active research topic in computational genomics. However, high dimensionalities of genotype data and exponential complexity of the search space with respect to the order of targeted interactions, make most existing interaction detection strategies practically inapplicable. Because they are capable of capturing interactions among input variables in addition to the nonlinear effects, decision trees and their ensembles have been recently demonstrated to be effective strategies in detecting interactions in GWAS data. However, an individual decision tree (DT) is highly susceptible to some major limitations, most importantly high variance error, data fragmentation and representational problems, which make them unreliable for use in feature selection in a stand-alone fashion. Ensemble approaches have been proposed to increase the robustness of weak learners such as DTs, by using multiple different and potentially complementary representations of the data. Some of the limitations of individual decision trees would still exist in the ensemble level which may impact their interaction detection performance. The objectives of this dissertation are to: • Study the systematic limitations of individual decision trees which may impact their interaction detection performance and the possible solutions; • Investigate the application of decision tree ensembles in interaction detections, with respect to the functional characteristics of the applied ensemble strategy; • Compare four well-known ensemble frameworks, namely AdaBoost, LogitBoost, Bagging and Random Forest, and their pros and cons as far as interaction detection is concerned; • Provide a unified framework to optimize the application of DT ensembles in interaction detection.
Advisors/Committee Members: Volkert, L. Gwenn.
Subjects: Bioinformatics; Computer Science
Keywords: GWAS; Epistasis; Interaction Detection; Variable Selection; Decision Trees; Ensemble Learning; AdaBoost; LogitBoost; Bagging; Random Forest
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10.
Bafna, Nitin Nemichand.
LABELING SCHEMES FOR SOME LOCATION PROBLEMS ON TREES.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2007, Kent State University
► Mostly all location problems are based on all nodes of a tree.…
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▼ Mostly all location problems are based on all nodes of a tree. However, in data communication networks only some nodes are communicating with data repository at a particular instance of time. In this thesis, labeling schemes and algorithms for some location problems on set of active nodes in a tree are presented. Let n be the total number of nodes in a tree T and at particular instance only K nodes be active. This thesis concentrates on solving location problems on set of K active nodes such as Median, Center and Diameter. We have also covered both cases such as relative and absolute center and relative and absolute median while considering the center and median problems.
Advisors/Committee Members: Dragan, Feodor.
Subjects: Computer Science
Keywords: Median, Center, Diameter, Labeling schema, distributed information
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11.
BANTAN, NOUMAN.
A ROUTING PROTOCOL AND ROUTING ALGORITHM FOR SPACE COMMUNICATION.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2007, Kent State University
► The proposed research is a development a routing protocol for space that…
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▼ The proposed research is a development a routing protocol for space that creates an infrastructure which enables routers on board spacecrafts to calculate near optimum routing tables ahead of time and on-demand when network changes occur. Our routing protocol for space communication, Space Open Shortest Path First (SOSPF), divides the routing domain (e.g., our solar system) into areas within areas which provides an orderly fashion of transmitting routing information throughout the routing domain. The concept of areas within SOSPF allows routing information of one area to be hidden within that area. In addition, since the trajectory of space crafts are either predictable (e.g., satellite constellation around Earth), preset (e.g., the International Space Station), or set on demand (e.g., a space shuttle), a router on board those spacecrafts calculates the time intervals where spacecrafts are in direct view with the calculating router and the propagation delays to those spacecrafts using the location of those spacecrafts and the local transmission capabilities. Then, those calculated values are dispersed throughout the routing domain. Also, this dissertation presents a routing algorithm which allows routers on board spacecrafts to use the received routing information (i.e., the time intervals and the propagation delay) to compute the routing table. This routing algorithm can compute shortest delay paths over conventional concurrent-link as well as intermittent-links using a store-and-forward communication scheme. Furthermore, this dissertation presents routing performance of this routing protocol in real space scenarios and shows how the SOSPF routing domain stays stable after link failures as the routing domain diameter grows to the end of our solar system.
Advisors/Committee Members: KHAN, JAVED I.
Subjects: Computer Science
Keywords: ROUTER; SOSPF; LSA; SOSPF router; ROUTING; NEIGHBORING ROUTERS; ROUTERS LIST
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12.
Batcher, Kenneth William.
Cache Miss Reduction Techniques for Embedded CPU Instruction Caches.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► Modern embedded systems are usually implemented by integrated circuits that contain commercial…
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▼ Modern embedded systems are usually implemented by integrated circuits that contain commercial microprocessor cores with internal instruction and data caches. Such systems are powerful and cost-effective, but the performance of the microprocessor cores is often limited by the performance of these internal caches. This limitation comes from the small size of the caches, the long latencies required to service a cache miss, and the high degree of cache misses that occur, especially for the instruction cache. However, the CPU cores are pre-designed, and the caches can be customized to only a limited extent, so the designers of these systems are limited in their ability to improve the cache performance. Fortunately, the software running on these systems is largely fixed and dedicated to a single application, which provides some opportunities to optimize the performance. Experimentation with real industrial designs and software has shown that instruction cache misses often occur as a cluster of misses; each cluster results in a large amount of CPU stalling that degrades the CPU performance as the misses are serviced. Contributing to this behavior are effects of real-time processing, multi-tasking operations, and interrupts that are common to embedded systems. In this dissertation, several techniques, involving both hardware and software enhancements, have been developed specifically to address the unique instruction cache miss problems that occur in real-time embedded systems. These techniques were tested on real industrial design and software sets, and were shown to be practical and cost effective solutions to these problems.
Advisors/Committee Members: Walker, Robert.
Subjects: Computer science
Keywords: Instruction Caches; Embedded; CPU; Real-Time; Interrupts; Processor Performance
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13.
Bellomo, Brad V.
AN OPEN SOURCE FRAMEWORK FOR BROWNIAN MOTION SIMULATION IN A NEUROMUSCULAR JUNCTION.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► Several simulation using Brownian motion to model neuromuscular junctions have been published…
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▼ Several simulation using Brownian motion to model neuromuscular junctions have been published in the past. Information published includes algorithm details, data files, simulation results and binary code, but source code was not made publicly available. A new open source implementation of the algorithms presented was created, to use as a platform for future research, and to attempt to validate the results of previous simulations.
Advisors/Committee Members: Ruttan, Arden.
Subjects: Computer science
Keywords: Brownian motion; simulation; neuromuscular junction
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14.
Bennett, Daniel M.
Tools and techniques for locating and steering parallel simulations through bifurcation points.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2010, Kent State University
► This dissertation involved two distinct, yet complementary goals. The primary focus is…
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▼ This dissertation involved two distinct, yet complementary goals. The primary focus is on steering parallel computations, and, in particular, on providing tools to simplify the task of creating user interfaces, when employing a steering and visualization package. We then apply these tools to create a complex customized interface which enables a user to detect, classify, and steer a sample parallel simulation of liquid crystal materials through a bifurcation point. Steering and visualization (STV) packages such as CUMULVS have been developed to allow user interaction with parallel programs. These packages tend to concentrate on data extraction and transportation, but ignore the problem of allowing scientists to easily build customized user interfaces to perform the actual steering. We believe that customized user interfaces are essential for monitoring and steering any complex computation, and that any STV environment should be accompanied by a set of tools which allow users to construct such an interface without detailed knowledge of the STV library. The principle result of this work is the creation of such a set of tools. These include a toolkit to simplify common tasks, when constructing such a user interface; a library of objects, which combine graphical display of data with the ability to steer that data; and a generic user interface framework, which requires minimal customization to deploy. The use, and usefulness of each of these tools is demonstrated by producing interfaces for a number of parallel numerical simulations. The utility of these tools for a large scale application is ultimately demonstrated by creating a complex custom interface to steer a large three dimensional parallel numerical simulation through the process of locating, classifying and following distinct paths out of a bifurcation point. The implementation of this latter application required the development further software. In particular, locating bifurcation points in the class of problems under investigation involves determining the geometric multiplicity of the minimum eigenvalue of the Jacobian as that eigenvalue approaches zero. To accomplish this, a parallel library, PCIRBLEIGS, was created. This library, based upon the irbleigs algorithm, can determine a few eigenvalues of a large, sparse, symmetric, Hermitian matrix distributed across multiple processes. This library is presented along with several examples and performance information.
Advisors/Committee Members: Farrell, Paul A.
Subjects: Computer Science
Keywords: steering and visualization, parallel computatation
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15.
Bobade, Kailas B.
Personalized Credential Negotiation Based on Policy Individualization in Federation.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2009, Kent State University
► In virtual business place, organizations store information of its members. Federated Access…
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▼ In virtual business place, organizations store information of its members. Federated Access Control Systems such as Shibboleth, Active Directory Federation Service allow virtual organizations to share their member’s information. Based on this information, members enjoy seamless access to federated resources. However in this federated world, a member’s information is divulged by her home organization. The member has little say in it. We have presented an extension to this work where members can personalize their own attribute release policy. As opposed to simple request reply based communication, such personalization inherently necessitates a mechanism of negotiation. To facilitate such personalization, we have presented negotiation enabled framework in federation which allows selection of negotiation flavor on per-need-basis i.e. Personalized Negotiation. This is supported by negotiation protocol which defines the ordering of the messages and unique message structure that carries negotiation information.
Advisors/Committee Members: Khan, Dr. Javed.
Subjects: Computer science; Information Systems
Keywords: Personalization, Federation, Privacy, Negotiation, Security
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16.
Chantamas, Wittaya.
A Multiple Associative Computing Model to Support the Execution of Data Parallel Branches Using the Manager-worker Paradigm.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2009, Kent State University
► The multiple associative computing (MASC) model is an enhanced strictly synchronous multi-SIMD…
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▼ The multiple associative computing (MASC) model is an enhanced strictly synchronous multi-SIMD model that is a generalization of an associative computing model (ASC) designed to support multiple ASC threads by using control parallelism to substantially improve the low processor utilization often criticized in SIMDs. The MASC model combines the advantages of both SIMD and MIMD models such as simple description, inherent synchronous operations, and ease of programming and debugging of SIMDs while providing flexible control flow support of MIMDs with small thread synchronization overheads. In this research, a cycle of simulations is used to show that a MASC model with constant associative operation word length and a MASC model with log n associative operation word length are equivalent in power. Moreover, the MASC model is powerful as the B-RMBM, S-RMBM, COMMON CRCW PRAM, and BRM models. This research presents a model description of a MASC model that uses the manager and worker instruction stream paradigm. A cycle precision software simulator, which is able to provide the exact number of overhead and execution cycles the model requires to execute a program, is used to demonstrate the performance of this implementation of MASC on various algorithms. The simulator is actually a software prototype for the manager-worker version with sufficient software details to allow a computer engineer to convert this software prototype into a hardware prototype of the manager-worker version of MASC. On the example multithreaded algorithms used, when processing large-scale instances using multiple workers, the MASC Floyd-Warshall algorithm shows strong scaling with constant time overhead and, for an average case, the MASC Quickhull algorithm shows good scaling with low overhead.
Advisors/Committee Members: Baker, Johnnie.
Subjects: Computer science
Keywords: associative computing; joint data and control parallelism; computational model; multi-SIMD; model simulation
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17.
Danturi, Praveen Kumar.
SELF-STABILIZING PHILOSOPHERS WITH GENERIC CONFLICTS.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2007, Kent State University
► We generalize the classic dining philosophers problem to separate the conflict and…
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▼ We generalize the classic dining philosophers problem to separate the conflict and communication neighbors of each process. Communication neighbors may directly exchange information while conflict neighbors compete for the access to the exclusive critical section of code. This generalization is motivated by a number of practical problems in distributed systems. We present a self-stabilizing deterministic algorithm KDP that solves a restricted version of the generalized problem where the conflict set for each process is limited to its k-hop neighborhood. We formally prove KDP correct and evaluate its performance. We then extend KDP to handle fully generalized problem. We further extend it to handle a similarly generalized drinking philosophers problem. We describe how KDP can be implemented in wireless sensor networks and demonstrate that this implementation does not jeopardize its correctness or termination properties.
Advisors/Committee Members: Nesterenko, Mikhail.
Subjects: Computer Science
Keywords: idle; conflict neighbors; KDP; Diners; neighbors; InvK
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18.
Davu, Sandeep.
Connection Oriented Mobility Using Edge Point Interactivity.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► With the advent of portable mobile devices and increasing usage of wireless…
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▼ With the advent of portable mobile devices and increasing usage of wireless communication medium, achieving seamless application space as the end-points change network attachment points is a demanding task. Connection Oriented mobility requires moving the connection abstraction to new attachment point without disturbing existing applications. As mobile nodes change the network attachment points, the existing connections become stale. Single layer solutions either require an infrastructure or significant re-engineering of protocol stack, which are hard to deploy. This thesis uses simple, light-weight re-organization (meta-engineering) on the protocols of the core networks to enhance them by making them interactive and transparent. Hidden information from the network core is exposed to higher layers for adaptability. A secure, flexible, application-aware cross-layer interactive architecture called Interactive Protocol for Mobile Networks(IPMN) was developed to handle non-indelible periods of disconnection and network handoffs. The inherently hidden information in one layer can be used by other layers to achieved optimized results. Events form Link Layer Network Layer and Transport Layer related to mobility are identified and subscribed by the application. The proposed solution achieves rapid, loss-free vertical handoffs, is event-based and does not require any infrastructural deployment. Since the triggers to the events are in application space there is no significant re-engineering of the core network or any protocol stack. Solutions are deployed in the application space, making it easy to modify, augment or replace existing solutions.
Advisors/Committee Members: Khan, Javed.
Subjects: Computer science
Keywords: connection-oriented mobility; handoff; cross-layer interaction; application aware mobility
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19.
Desai, Harit S.
Evaluation and Tuning of Gigabit Ethernet performance on Clusters.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2007, Kent State University
► Cluster computing imposes heavy demands on the communication network. Gigabit Ethernet technology…
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▼ Cluster computing imposes heavy demands on the communication network. Gigabit Ethernet technology can provide the required bandwidth to meet these demands. However, it has also shifted the communication bottleneck from network media to protocol processing. In this thesis, we present an overview of Gigabit Ethernet technology and study the end-to-end Gigabit Ethernet communication bandwidth and latency. Performance graphs are collected using NetPIPE which clearly show the performance characteristics of TCP/IP and VIA over Gigabit Ethernet. Here we discuss the communication performance attainable with a PC cluster connected by a Gigabit Ethernet network. Gigabit Ethernet is the third generation of Ethernet technology and offers raw bandwidth of 1 Gbps. The focus of this work is to discuss the Gigabit Ethernet technology, to evaluate and analyze the end-to-end communication latency and achievable bandwidth, and to monitor the effects of software and hardware components on the overall network performance.
Advisors/Committee Members: Farrell, Paul A.
Subjects: Computer Science
Keywords: Gigabit ethernet performance; Cluster computing; TCP/IP performance
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20.
Drabu, Yasir.
Gateway Placement And Fault Tolerance In QoS Aware Wireless Mesh Networks.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2010, Kent State University
► Wireless Mesh Networks (WMN's), in the form of WiFi (802.11x) or WiMax…
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▼ Wireless Mesh Networks (WMN's), in the form of WiFi (802.11x) or WiMax (802.16x), or their integrations have been proposed as an effective communication alternative for ubiquitous last mile wireless broadband access. They can be viewed as a hybrid between traditional cellular, point-to-point wireless systems, and ad-hoc networks. They offer more flexibility, mobility, coverage and expandability compared to their traditional counterparts at the expense of complex architecture and deployment structure. Though WMNs hold great promise in abetting network ubiquity, there still remain several challenges in the design and development of WMN's to support diverse services with different quality of service (QoS) requirements and large scale deployment. The focus of this dissertation is to address some of the core issues that directly affect the QoS in terms of delay, throughput, and fault tolerance. First we look at the deployment problem of the placement of wired gateways. This aspect of WMNs has a significant impact on the network's throughput performance, cost and capacity to satisfying the quality of service requirements. In the context of gateway placement, the QoS is influenced by the number of gateways, the number of nodes served by each gateway, the location of the gateways, and the relay load on each wireless router. While finding an optimal solution to simultaneously satisfy all the above constraints is known to be an NP-hard problem, near optimal solutions can be found within the feasibility region in polynomial time using various heuristic methods. In the initial part of this dissertation, we first present a near optimal heuristics algorithm for gateway placement that facilitates QoS provisioning and fault tolerance in WMNs. We then investigate fault tolerance and recovery problems in WMNs. We present a fault recovery algorithm that can exploit the known geometry of a regular cellular mesh network. While keeping the QoS metrics intact, we consider a post-deployment fault recovery algorithm and pre-deployment fault tolerance planning.
Advisors/Committee Members: Peyravi, Hassan.
Subjects: Computer Science
Keywords: wireless mesh networks, deployment algorithms, fault tolerant provisioning
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21.
Dragan, Natalia.
The Emergent Laws of Method and Class Stereotypes in Object Oriented Software.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2010, Kent State University
► The dissertation investigates how to characterize software at various levels of abstraction…
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▼ The dissertation investigates how to characterize software at various levels of abstraction (e.g., method, class, or system). Stereotypes are a powerful semantic mechanism in UML and represent generalizations that reflect an intrinsic or atomic behavior of a method or a class. An empirical study of a number of open source systems forms the basis for a set of emergent stereotypes of the software abstractions at the various levels. A mechanism to automatically reverse engineer these stereotypes from existing systems is presented along with a means to re-document classes and methods with their corresponding stereotypes. The basis for the automatic identification of class stereotypes is the distribution of method stereotypes. Entire systems can also be characterized by the method stereotypes distribution. This work is further extended to the characterization of changes in software during evolution. Automatically classifying commits and uncovering evolution patterns of method stereotypes is done to assist developers to gain a high-level perspective of the design over a system’s evolution. The research contribution of this work includes a taxonomic description of object-oriented method stereotypes and class stereotypes. Further contributions include leveraging the approach for method stereotypes extraction for the implementation of tools for source code re-documentation, identification of descriptors for software systems and their classifications, development of a tool for reverse engineering class stereotypes, and implementation of a tool for the semantic categorization of commits. The final contribution is the evaluation of the approach by performing empirical studies on historical data for a wide range of open source object-oriented C++ software systems that can serve as a benchmark for further investigations and studies.
Advisors/Committee Members: Maletic, Jonathan I.
Subjects: Computer Science
Keywords: reverse engineering; method stereotypes; class stereotypes
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22.
DUTTA, BINAMRA.
Enterprise Software Metrics: How To Add Business Value.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2009, Kent State University
► Although there is no consensus on what metrics work best for a…
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▼ Although there is no consensus on what metrics work best for a specific organization, it is still a widely accepted belief that software metrics can help organizations in achieving better productivity. In the course of developing software, it is common for software teams to focus more on the immediate deliverable. For them to be sure that they are on the right path of achieving their business goal, some kind of measurement program is needed to measure and monitor the progress correctly and efficiently. In this research I have tried to collect and review the existing methodologies for establishing a successful metrics program in software development industry. I have reviewedexisting information for establishing a metrics program in an organization and propose ideas to further refine them for step by step practical application in organizations which follow agile development practices. Such assessment techniques have also been successfully used in various fields in the past. Assessment techniques in schools and standardized testing techniques in academics are one of the very popular ones. I believe that the human anxiety that accompanies any new metrics program being instituted in an organization is similar to anxiety connected with classroom assessment. Traditionally, schools have used grade assessments with the belief that maximizing anxiety will fuel growth in learning. In recent years a shift has occurred in schools to motivate students to become more competent and using assessment as a power tool as opposed to just a ‘ranking scale’. To better understand the people management aspect of measurement and the motivational intricacies involved, I have outlined the efforts made in classroom assessment in the past five decades to connect assessment with learning improvement. I believe that some of those techniques can be successfully applied for motivating people and creating a positive measurement culture within an organization.
Advisors/Committee Members: Melton, Austin.
Keywords: METRICS PROGRAMS; AGILE SOFTWARE DEVELOPMENT; SOFTWARE METRICS; Defect
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23.
Du, Xiaoxi.
Migration Motif: A Spatial-Temporal Pattern Mining Approach for Financial Markets.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2009, Kent State University
► A recent study by two prominent finance researchers, Fama and French, introduces…
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▼ A recent study by two prominent finance researchers, Fama and French, introduces a new framework for studying risk vs. return: the migration of stocks across size-value portfolio space. Given the financial events of 2008, this first attempt to disentangle the relationships between migration behavior and stock returns is especially timely. Their work, however, derives results only for market segments, not individual companies, and only for one-year moves. Thus, we see a new challenge for financial data mining: how to capture and categorize the migration of individual companies, and how such behavior affects their returns. We propose a novel data mining approach to study the multi-year movement of individual companies. Specifically, we address the question: “How does one discover frequent migration patterns in the stock market?” We present a new trajectory mining algorithm to discover migration motifs in financial markets. Novel features of this algorithm are its handling of approximate pattern matching through a graph theoretical method, maximal clique identification, and incorporation of temporal and spatial constraints. We have performed a detailed study of the NASDAQ, NYSE, and AMEX stock markets, over a 43-year span. We successfully find migration motifs that confirm existing finance theories and other motifs that may lead to new financial models.
Advisors/Committee Members: Jin, Ruoming.
Subjects: Computer science
Keywords: Migration Motif; Trajectory Mining; Sequential Pattern Mining; Time Series Clustering
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24.
Eshaque, Adnan.
A Mathematics Glossary Web Application and Service.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2007, Kent State University
► At the Institute for Computational Mathematics (ICM), research on Web-based Mathematics Education…
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▼ At the Institute for Computational Mathematics (ICM), research on Web-based Mathematics Education (WME) aims to establish a new and much more effective paradigm for supporting and delivering mathematics education. An important aspect of learning mathematics is, understanding terminology and being able to look up the meaning of terms readily. Existing mathematics glossaries are little more than lists of terms placed online. As part of the WME effort, this thesis describes the design and implementation of the Mathematics Glossary (MG) System that provides an easy, effective and structured way for representing, storing, retrieving and communicating mathematical terminologies and supports interoperability between applications through an XML based language MgML (Mathematics Glossary Markup Language). The MG Web Application supports browsing while the MG Web Service supports programmatic retrieval of glossary items. The MG System works well with WME but is an independent and self-contained tool.
Advisors/Committee Members: Wang, Paul.
Subjects: Computer Science
Keywords: MGML; MG Web Service; MATHEMATICS; GLOSSARY
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25.
Fan, Chen.
DISTANCE FIELD TRANSFORM WITH AN ADAPTIVE ITERATION METHOD.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2009, Kent State University
► In my thesis, a novel distance field transform Method is proposed basing…
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▼ In my thesis, a novel distance field transform Method is proposed basing on an iterative method adaptively performed on an evolving active band. Our method utilizes a narrow band to store active grid points being computed. Unlike the conventional fast marching method, we do not maintain a priority queue, and instead, perform iterative computing inside the band. This new algorithm alleviates the programming complexity and the data-structure (e.g. a heap) maintenance overhead, and leads to a parallel amenable computational process. During the active band propagating from a starting boundary layer, each grid point stays in the band for a lifespan time, which is determined by analyzing the particular geometric property of the grid structure. In this way, we find the Face-Centered Cubic (FCC) grid is a good 3D structure for distance transform. We further develop a multiple-segment method for the band propagation, achieving the computational complexity of O(m · N) with a segment-related constant m.
Advisors/Committee Members: Zhao, Ye.
Subjects: Computer science
Keywords: distance field, distance transform, narrow band, multi-segment
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26.
FAN, WEIGUO.
USING MOLECULAR SIMILARITY ANALYSIS FOR STRUCTURE-ACTIVITY RELATIONSHIP STUDIES.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2012, Kent State University
► This dissertation describes an efficient algorithm for finding the maximal common substructure…
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▼ This dissertation describes an efficient algorithm for finding the maximal common substructure (MaCS) of a pair of molecules, each represented as a labeled graph. The size of the MaCS, expressed as the total number of non-hydrogen atoms and bonds (NAB), is used as the basis for calculating a molecular similarity index (MSI) and a topological distance parameter (TD). The theoretical basis of the algorithm and running time enhancements are discussed. The algorithm uses a subgraph isomorphism approach to finding the maximum common subgraph (MCSG) as well as its implementation in a program named TOPSIM (TOPological SIMilarity). Also described are new algorithms for eliminating the output of redundant substructure pairs and identifying topologically equivalent substructure pairs. In generating the maximum common subgraph (MCSG), the algorithm can handle the special cases when one molecule is a subgraph or a mirror image of another molecule or when the two molecules are identical but have different molfile representations. The algorithm for building the minimum superstructure (MiCS) of two or more molecules and its application are also addressed in this dissertation. TOPSIM is used to analyze molecular structural similarities. Because a molecule‟s structure relates to its biological activities, structurally similar molecules are often compared regarding their activities in molecular research. SAM (Structure-Activity Map) graphically displays one activity across a group of molecules. This dissertation provides advances in the molecular similarity research using improvements developed for SAM and TOPSIM. An algorithm was developed to identify linearly related molecules called structural ordering (SO). Advantage of using SO with SAM is demonstrated in this study by examining the antioxidant activities of flavonoids. Besides the two-dimensional SAM which only displays one activity across multiple molecules, this dissertation proposed a third dimension called a layer, along which various activities can be displayed. The study of multiple human-beneficial activities of flavonoids was conducted to illustrate the applicability of the 2-D and 3-dimensional SAMs. Together with the SO algorithm, important multi-structure-activity relationships were identified. A web-based version of TOPSIM was developed to allow the remote accesses. Some limitations of the algorithms and directions to future work are also discussed in this dissertation.
Advisors/Committee Members: Baker, Johnnie.
Subjects: Computer Science
Keywords: Molecular Similarity Analysis, QSAR, Structure-activity Maps, Maximal Common Substructure, Drug Design
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27.
Frey, Jeffrey Daniel.
Finding Song Melody Similarities Using a DNA String Matching Algorithm.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► Music plays an important role in everyday life, and the introduction of…
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▼ Music plays an important role in everyday life, and the introduction of popular portable music players and online song purchasing brought rapid growth to the music industry in the past few years. Copyright infringement, royalty distribution, and the introduction of new songs to consumers are complex problems that plague the industry, but could be solved by an effective method of searching databases for song melody similarities. Though research has been conducted in this area, there are other disciplines with well-developed algorithms that could also be adapted for this purpose. Scientists in the field of bioinformatics employ string matching algorithms to do such things as find the closest substrings while comparing two deoxyribonucleic acid (DNA) strings. The Smith-Waterman algorithm is commonly used for this purpose and not only finds the exact string matches, but has a unique way of weighting insertions, deletions, and substitutions to identify the closest matching substrings. In this paper, the author proves that, with modifications to handle melody instead of DNA strings, algorithms such as Smith-Waterman are uniquely suited for matching a given song to a database of songs. A brief discussion of copyright infringement, royalty distribution, and the introduction of new songs to consumers will be followed by an explanation of music, melodies, themes, and how melodies of songs are documented. Then the field of music information retrieval and surrounding issues will be discussed. An overview of existing song search applications will be provided before moving on to an explanation of the Smith-Waterman algorithm and its application in the biosciences. Finally, a suitable implementation of the Smith-Waterman algorithm will be presented, including how it was modified for song melody matching, addressing the issues of pitch, note duration, and song tempo. In conclusion, the results will show why DNA string matching algorithms, such as Smith-Waterman, are a perfect match for identifying similar song melodies.
Advisors/Committee Members: Baker, Johnnie.
Subjects: Bioinformatics; Computer science; Music
Keywords: music, melody, song, mir, deoxyribonucleic acid, DNA, smith, waterman
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28.
Fuhry, David P.
Skylines in Metric Space.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► Recent interest in solving the skyline query differs from decades-earlier work on…
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▼ Recent interest in solving the skyline query differs from decades-earlier work on the equivalent maximum vector problem in that the queried dataset is no longer assumed to fit into main memory. Given a set of points P and a set of query points Q, the skyline query returns the points p ∈ P where ∀p ∈ P, p′ ∈ P for which p′ dominates p. A point z′ dominates z when it is not further from all q ∈ Q and it is closer to at least one q ∈ Q. This special-case of the dynamic skyline query is efficiently answerable in low-dimensional, restricted cases using known algorithms. We introduce new algorithms which can efficiently answer the skyline query in more general metric spaces. Several novel extensions are introduced to minimize the number of distance and comparison computations. Detailed experimental results demonstrate their effectiveness.
Advisors/Committee Members: Jin, Ruoming.
Subjects: Computer science
Keywords: Skyline; Metric Space; B2M2S; N2RS
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29.
Gedela, Naga Venkata Praveen babu.
MEASUREMENT AND ITS HISTORICAL CONTEXT.
Degree: MS, College of Arts and Sciences / Department of Computer Science, 2008, Kent State University
► Measurement is important in every field of science. It is easy to…
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▼ Measurement is important in every field of science. It is easy to measure attributes in some fields of science and difficult in others. Software engineering is a field of science where measurement is heavily used. Many software metric models were designed for different phases of software engineering including requirements, design, coding, implementing, testing and maintenance. Well known researchers like Norman Fenton focused measurement research in software engineering on the representational theory of measurement. In representational measurement, we understand and collect data from empirical observations and arrange them in some logical fashion in terms of familiar mathematical structures. The reason researchers in software measurement are interested in measurement theory is they believe that measurement theory principles, which have for the most part been developed for measurement in physical sciences, can help produce good software metrics. Interestingly, it should be noted that the measurement ideas of Norman Campbell who was a “father” of modern measurement are not in complete agreement with the representation theory of measurement. According to representation measurement theory, the set of entities and the relations of a measurable attribute have to be similar to a set of numerals and their relations. In fact, they should be isomorphic with each other. Relations on a set of entities need to be experimentally demonstrated or theoretically justified. Unfortunately, users of software metrics often assume that every relation which exists on a set of numerals also exists on the set of entities. Said differently, the properties of the measurement values should reflect the properties of the set of entities and their relations. The relations on the set of numerals should be in complete agreement with set of entities and their relations. But in software measurement, software designers do not provide adequate attention to this requirement. Software measurements is different enough from measurement in other fields, including the physical sciences, that software measurement needs to develop a measurement theory which takes in account the needs, requirements and conditions of software measurement. My thesis analyzes different measurement methods and ideas from classical measurement theory and representational theory and analyzes different problems faced in software measurement.
Advisors/Committee Members: Melton, Austin.
Subjects: Computer science
Keywords: Software Measurement; program length; attributes; Measurement Theory
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30.
Guo, Yujun.
Medical Image Registration and Application to Atlas-Based Segmentation.
Degree: PhD, College of Arts and Sciences / Department of Computer Science, 2007, Kent State University
► A fundamental problem in medical image analysis is image registration, which is…
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▼ A fundamental problem in medical image analysis is image registration, which is the task of finding geometric relationships between corresponding points in multiple images of the same scene. Various registration methods have been proposed over recent years, among which registration strategies based on maximization of mutual information have been widely used in multi-modality image registration. However, applying mutual information (MI) to original intensities only takes statistical information into consideration, while spatial information is completely neglected. In the first part of this dissertation, a novel approach is proposed to incorporate spatial information into MI through gradient vector flow (GVF). With this approach, MI now is calculated from the GVF-intensity (GVFI) map of the original images instead of their intensity values. The algorithm is implemented and applied to multi-modality brain image registration to test the accuracy and robustness of the proposed method. Experimental results show that the success rate of our method is higher than that of traditional MI-based registration. In many applications, a rigid transformation is insufficient to describe the spatial relationship between two images. Thus, elastic transformations, or non-rigid transformations are often required in image registration. In the second part of this dissertation, we present a generalized gradient-guided non-rigid registration strategy. The derivation procedure is similar to that by Lucas and Kanade, but in a more general manner. In experiments, we compare the proposed method and other gradient-guided methods in the literature, using both synthetic and real images. It is shown that methods combining gradients from both source and target images usually perform better. In the third part, we apply previously described registration methods to atlas-based brain magnetic resonance (MR) image segmentation. A pre-labeled image or atlas is first registered to the subject image to be segmented, and the deformation field for each voxel is derived. Then the structures delineated in the atlas are projected onto the subject image by applying the deformation field to the atlas mask. We validate our results using the datasets from IBSR. Quantitative comparisons using various criteria show that the proposed method is better than or comparable to published methods.
Advisors/Committee Members: Lu, Cheng-Chang.
Keywords: medical image registration; mutual information (MI); similarity measure; spatial information; gradient vector flow (GVF); gradient vector flow intensity; demons algorithm; non-rigid transformation; generalized gradient-guided non-rigid registration
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