Computer Sciences Commons^™

Evaluation Of The Ad Hoc On-Demand Distance Vector Routing Protocol For Mobile Ad Hoc Networks, Amber J. Rickmon

Theses and Dissertations

Routing protocols designed for wired networks cannot be used in mobile ad hoc networks (MANETs) due to the dynamic topology, limited throughput, and energy constraints. New routing protocols have been designed for use in MANETs, but have not been thoroughly tested under realistic conditions such as node movement, number of sources, the presence of obstacles, and node speed. This research evaluates the performance of ad hoc on-demand distance vector routing with respect to throughput, goodput ratio, end-to-end (ETE) delay, node pair packet delivery rate, and node pair end-to-end delay. It shows these performance metrics vary significantly according to the choice …

Efficient Generation Of Social Network Data From Computer-Mediated Communication Logs, Jason Wei Sung Yee

Theses and Dissertations

The insider threat poses a significant risk to any network or information system. A general definition of the insider threat is an authorized user performing unauthorized actions, a broad definition with no specifications on severity or action. While limited research has been able to classify and detect insider threats, it is generally understood that insider attacks are planned, and that there is a time period in which the organization's leadership can intervene and prevent the attack. Previous studies have shown that the person's behavior will generally change, and it is possible that social network analysis could be used to observe …

A Framework For Extraction Plans And Heuristics In An Ontology-Based Data-Extraction System, Alan E. Wessman

Theses and Dissertations

Extraction of information from semi-structured or unstructured documents, such as Web pages, is a useful yet complex task. Research has demonstrated that ontologies may be used to achieve a high degree of accuracy in data extraction while maintaining resiliency in the face of document changes. Ontologies do not, however, diminish the complexity of a data-extraction system. As research in the field progresses, the need for a modular data-extraction system that de-couples the various functional processes involved continues to grow.

In this thesis we propose a framework for such a system. The nature of the framework allows new algorithms and ideas …

Java Performance Of The Rijndael Encryption Algorithm Across Compilers And Virtual Machines, Gregory Leavitt Orgill

Theses and Dissertations

The Rijndael encryption algorithm has recently been published as the Advanced Encryption Standard (AES), a Federal Information Processing Standard, and is being accepted by developers and designers as the algorithm of choice where encryption is required. Java is becoming the language of choice for E-Business applications, many of which require cryptography. The performance of any Java application is dependent on the compiler and virtual machine used to compile and interpret. Prior research has provided performance information for the Rijndael algorithm in Java for specific virtual machines. This research includes the development of a Rijndael implementation in Java. Using Java system …

Computer-Simulation-Assisted Lean Manufacturing Training, Luoding Wang

Theses and Dissertations

This thesis assesses the potential of using computer simulation to aid existing lean manufacturing training methods such as lecture and live simulation. An investigation of this possibility was carried out in conjunction with UMEP's Lean 101 class. In the study, two experimental computer simulation models demonstrating the push and pull production scenarios were constructed using ProModel software. Simulation models were equipped with a Visual Basic interface to aid trainees to manipulate the model via ActiveX. Constructed computer simulation was compared with live simulation to answer these research questions: 1. Was computer simulation able to teach additional lean concepts not covered …

Attribute-Level Versioning: A Relational Mechanism For Version Storage And Retrieval, Charles Andrew Bell

Theses and Dissertations

Data analysts today have at their disposal a seemingly endless supply of data and repositories hence, datasets from which to draw. New datasets become available daily thus making the choice of which dataset to use difficult. Furthermore, traditional data analysis has been conducted using structured data repositories such as relational database management systems (RDBMS). These systems, by their nature and design, prohibit duplication for indexed collections forcing analysts to choose one value for each of the available attributes for an item in the collection. Often analysts discover two or more datasets with information about the same entity. When combining this …

Analysis Of Perturbation-Based Testing Methodology As Applied To A Real-Time Control System Problem, Richard A. Stutler

Theses and Dissertations

Perturbation analysis is a software analysis technique used to study the tail function of a program by inserting an error into an executing program using data state mutation. The impact of this induced error on the output is then measured. This methodology can be used to evaluate the effectiveness of a given test set and in fact can be used as a means to derive a test set which provides coverage for a given program. Previous research has shown that there is a "coupling effect" such that test sets that identify simple errors will also identify more complex errors. Thus …

Fuzzy Membership Function Initial Values: Comparing Initialization Methods That Expedite Convergence, Stephanie Scheibe Lee

Theses and Dissertations

Fuzzy attributes are used to quantify imprecise data that model real world objects. To effectively use fuzzy attributes, a fuzzy membership function must be defined to provide the boundaries for the fuzzy data. The initialization of these membership function values should allow the data to converge to a stable membership value in the shortest time possible. The paper compares three initialization methods, Random, Midpoint and Random Proportional, to determine which method optimizes convergence. The comparison experiments suggest the use of the Random Proportional method.

Measuring Community Consensus In Facial Characterization Using Spatial Databases And Fuzzy Logic, James Lee Mastros

Theses and Dissertations

Spatial databases store geometric objects and capture spatial relationships that can be used to represent key features of the human face. One can search spatial databases for these objects, and seek the relationships between them, using fuzzy logic to provide a natural way to describe the human face for the purposes of facial characterization. This study focuses on community perception of short, average, or long nose length. Three algorithms were used to update community opinion of nose length. All three methods showed similar trends in nose length classification which could indicate that the effort to extract spatial data from images …

Intelligent Autonomous Data Categorization, Edward Graham Finegan

Theses and Dissertations

The goal of this research was to determine if the results of a simple comparison algorithm (SCA) could be improved by adding a hyperspace analogue to language model of memory (HAL) layer to form NCA. The HAL layer provides contextual data that otherwise would be unavailable for consideration. It was found that NCA did improve the results when compared to SCA alone. However, NCA added complexity problems that limit its practicality. The complexity of this algorithm is On3 where n is equal to the number of unique symbols in the data. While there is a relativity reasonable soft upper bound …

Forensic Analysis Of Digital Image Tampering, Jonathan R. Sturak

Theses and Dissertations

The use of digital photography has increased over the past few years, a trend which opens the door for new and creative ways to forge images. The manipulation of images through forgery influences the perception an observer has of the depicted scene, potentially resulting in ill consequences if created with malicious intentions. This poses a need to verify the authenticity of images originating from unknown sources in absence of any prior digital watermarking or authentication technique. This research explores the holes left by existing research; specifically, the ability to detect image forgeries created using multiple image sources and specialized methods …

Annotation Manager: An Automated Web-Based Content Management System For Digital Libraries With Annotated Bibliographies, Frenny Thomas

Theses and Dissertations

With the expansion of the World Wide Web in the 90s, individuals (especially students) are always on a quest for information resources especially in the form of Web sites. Yet many of them are overwhelmed when faced with deciding which site will best suit their research needs. As a result, these individuals may select a resource for less than optimal reasons. To ease some of the burden, libraries have made great advances to provide a place to organize information resources. Such places are called library portals, and they typically provide a gateway to web resources by categorizing and annotating them …

Analysis Of Hostile Network Reconnaissance To Anticipate And Mitigate Network Attacks, Luis Angel Rivera

Theses and Dissertations

Network security systems today such as current intrusion detection systems, intrusion prevention systems and firewalls are good at reacting to attacks as they occur or shortly after they occur. Current security systems lack the ability to identify and detect the activity that usually precedes an attack. This activity is known as network reconnaissance. In this thesis we have developed a technique that can assist current security systems to detect hostile network reconnaissance to anticipate and mitigate network attacks.

On The Use Of Randomness In Computing To Perform Intelligent Tasks, Ryan Scott Regensburger

Theses and Dissertations

The study of Artificial Intelligence attempts to simulate the processes of human intelligence in a set of computable algorithms. The purpose of Random Algorithms in this field is to provide a best-guess approach at identifying the unknown. In this thesis, research shows that random algorithms are able to break down many intelligent processes into a set of solvable problems. For example, solving puzzles and playing games involve the same estimating ability shown in standard problems such as the Coupon Collector problem or the Monty Hall problem. This thesis shows Random Algorithmic applications in two overlapping categories of intelligent behavior: Pattern …

Modeling The Spread And Prevention Of Malicious Mobile Code Via Simulation Cs-2004-15, Christopher Brian Shirey

Theses and Dissertations

Malicious mobile code causes billions of dollars every year in damages, and that cost keeps increasing. Traditional signature-based anti-virus software is a reactive solution that can not detect fast spreading malicious code quickly enough to prevent widespread infection. If we hope to prevent widespread infection of future malicious mobile code, new prevention techniques must be developed that either stop a new infection completely, or at least limit the spread until signature-based anti-virus software can be updated. Simulators exist that model the spread of malicious mobile code, but none currently exists that can efficiently model host-based and network-based spread prevention techniques …

Automating The Extraction Of Domain-Specific Information From The Web-A Case Study For The Genealogical Domain, Troy L. Walker

Theses and Dissertations

Current ways of finding genealogical information within the millions of pages on the Web are inadequate. In an effort to help genealogical researchers find desired information more quickly, we have developed GeneTIQS, a Genealogy Target-based Information Query System. GeneTIQS builds on ontology-based methods of data extraction to allow database-style queries on the Web. This thesis makes two main contributions to GeneTIQS. (1) It builds a framework to do generic ontology-based data extraction. (2) It develops a hybrid record separator based on Vector Space Modeling that uses both formatting clues and data clues to split pages into component records. The record …

Target-Dominant Chinese-English Machine Translation, Dan Su

Theses and Dissertations

Information exchange is increasing rapidly with the advent of globalization. As the language spoken by the most people in today's world, Chinese will play an important role in information exchange in the future. Therefore, we need an efficient and practical means to access the increasingly large volume of Chinese data. This thesis describes a target-dominant Chinese-English machine translation system, which can translate a given Chinese news sentence into English. We conjecture that we can improve the state of the art of MT using a TDMT approach. This system has participated in the NIST (National Institute of Standards and Technology) 2004 …

Does The Halting Necessary For Hardware Trace Collection Inordinately Perturb The Results?, Myles G. Watson

Theses and Dissertations

Processor address traces are invaluable for characterizing workloads and testing proposed memory hierarchies. Long traces are needed to exercise modern cache designs and produce meaningful results, but are difficult to collect with hardware monitors because microprocessors access memory too frequently for disks or other large storage to keep up. The small, fast buffers of the monitors fill quickly; in order to obtain long contiguous traces, the processor must be stopped while the buffer is emptied. This halting may perturb the traces collected, but this cannot be measured directly, since long uninterrupted traces cannot be collected. We make the case that …

Real-Time Image Enhancement Using Texture Synthesis, Matthew J. Sorensen

Theses and Dissertations

This thesis presents an approach to real-time image enhancement using texture synthesis. Traditional image enhancement techniques are typically time consuming, lack realistic detail, or do not scale well for large magnification factors.

Real-time Enhancement using Texture Synthesis (RETS) combines interpolation, classification, and patch-based texture synthesis to enhance low-resolution imagery, particularly aerial imagery. RETS uses as input a low-resolution source image and several high-resolution sample textures. The output of RETS is a high-resolution image with the structure of the source image, but with detail consistent with the high-resolution sample textures. We show that RETS can enhance large amounts of imagery in …

Improved Signal Integrity In Ieee 1149.1 Boundary Scan Designs, Efren De Jesus Rangel Taboada

Theses and Dissertations

This work is an analysis of solutions to problems derived from inherent timing and signal integrity issues in the use and application of the IEEE 1149.1 Standard at the board level in conjunction with its test system. Setup or hold times violations may occur in a boundary scan chain using IEEE 1149.1 compliant devices. A practical study of the TDI-TDO scan data path has been conducted to show where problems may arise in relationship to a particular board topology and test system. This work points to differences between passing and failing scan path tests for problem characterization. Serial data flow …

Intelligent, Pervasive And Context-Aware Promotion Delivery Framework For Wireless Mobile Devices, Karthik Harihar

Theses and Dissertations

Mobile devices are now powerful systems and are the main vehicles for m- commerce. Market research predicts enormous potential for m-commerce applications and services [9], [10], [11], [12]. Unique features such as portability, location-awareness and personalization make mobile devices effective tools for targeted advertising. Several mobile marketing frameworks have been designed that deliver promotions based on location information and user preferences [3], [4], [5]. These frameworks have several drawbacks that need to be addressed in order to be effective. The aim of this thesis is to research a simple and efficient framework for targeted and personalized advertising. This work presents …

Disk Based Model Checking, Tonglaga Bao

Theses and Dissertations

Disk based model checking does not receive much attention in the model checking field becasue of its costly time overhead. In this thesis, we present a new disk based algorithm that can get close to or faster verification speed than a RAM based algorithm that has enough memory to complete its verification. This algorithm also outperforms Stern and Dill's original disk based algorithm. The algorithm partitions the state space to several files, and swaps files into and out of memory during verification. Compared with the RAM only algorithm, the new algoritm reduces hash table insertion time by reducing the cost …

Vision-Based Human Directed Robot Guidance, Richard B. Arthur

Theses and Dissertations

This paper describes methods to track a user-defined point in the vision of a robot as it drives forward. This tracking allows a robot to keep itself directed at that point while driving so that it can get to that user-defined point. I develop and present two new multi-scale algorithms for tracking arbitrary points between two frames of video, as well as through a video sequence. The multi-scale algorithms do not use the traditional pyramid image, but instead use a data structure called an integral image (also known as a summed area table). The first algorithm uses edge-detection to track …

Network-Layer Selective Security, Casey T. Deccio

Theses and Dissertations

The Internet and other large computer networks have become an integral part of numerous daily processes. Security at the network layer is necessary to maintain infrastructure survivability in the case of cyber attacks aimed at routing protocols. In order to minimize undesired overhead associated with added security at this level, the notion of selective security is proposed. This thesis identifies elements in network topologies that are most important to the survivability of the network. The results show that the strategic placement of network security at critical elements will improve overall network survivability without the necessity of universal deployment.

Pattern Search Ranking And Selection Algorithms For Mixed-Variable Optimization Of Stochastic Systems, Todd A. Sriver

Theses and Dissertations

A new class of algorithms is introduced and analyzed for bound and linearly constrained optimization problems with stochastic objective functions and a mixture of design variable types. The generalized pattern search (GPS) class of algorithms is extended to a new problem setting in which objective function evaluations require sampling from a model of a stochastic system. The approach combines GPS with ranking and selection (R&S) statistical procedures to select new iterates. The derivative-free algorithms require only black-box simulation responses and are applicable over domains with mixed variables (continuous, discrete numeric, and discrete categorical) to include bound and linear constraints on …

Visual Unified Modeling Language For The Composition Of Scenarios In Modeling And Simulation Systems, Daniel E. Swayne

Theses and Dissertations

The Department of Defense uses modeling and simulation systems in many various roles, from research and training to modeling likely outcomes of command decisions. Simulation systems have been increasing in complexity with the increased capability of low-cost computer systems to support these DOD requirements. The demand for scenarios is also increasing, but the complexity of the simulation systems has caused a bottleneck in scenario development due to the limited number of individuals with knowledge of the arcane simulator languages in which these scenarios are written. This research combines the results of previous AFIT efforts in visual modeling languages to create …

An Ecological Display For Robot Teleoperation, Robert W. Ricks

Theses and Dissertations

This thesis presents an interface for effectively teleoperating robots that combines an ecological display of range and video information with quickening based on dead-reckoning prediction. This display is built by viewing range and video information from a virtual camera trailing the robot. This is rendered in 3-D by using standard hardware acceleration and 3-D graphics software. Our studies demonstrate that this interface improves performance for most people, including those that do not have much previous experience with robotics. These studies involved 32 test subjects in a simulated environment and 8 in the real world. Subjects were required to drive the …

A Qualitative Method For Dynamic Transport Selection In Heterogeneous Wireless Environments, Heidi R. Duffin

Theses and Dissertations

Computing devices are commonly equipped with multiple transport technologies such as IrDA, Bluetooth and WiFi. Transport switching technologies, such as Quality of Transport (QoT), take advantage of this heterogeneity to keep network sessions active as users move in and out of range of various transports or as the networking environment changes. During an active session, the goal is to keep the device connected over the best transport currently available. To accomplish that, this thesis introduces a two-phase decision making protocol. In phase one, intra-device prioritization, users indicate the relative importance of criteria such as speed, power, service charge, or signal …

Preserving Trust Across Multiple Sessions In Open Systems, Fuk-Wing Thomas Chan

Theses and Dissertations

Trust negotiation, a new authentication paradigm, enables strangers on the Internet to establish trust through the gradual disclosure of digital credentials and access control policies. Previous research in trust negotiation does not address issues in preserving trust across multiple sessions. This thesis discusses issues in preserving trust between parties who were previously considered strangers. It also describes the design and implementation of trust preservation in TrustBuilder, a prototype trust negotiation system. Preserving trust information can reduce the frequency and cost of renegotiation. A scenario is presented that demonstrates that a server supporting trust preservation can recoup the cost of the …

Grouping Search-Engine Returned Citations For Person-Name Queries, Reema Al-Kamha

Theses and Dissertations

In this thesis we present a technique to group search-engine returned citations for person-name queries, such that the search-engine returned citations in each group belong to the same person. To group the returned citations we use a multi-faceted approach that considers evidence from three facets: (1) attributes, (2) links, and (3) page similarity. For each facet we generate a confidence matrix. Then we construct a final confidence matrix for all facets. Using a threshold, we apply a grouping algorithm on the final confidence matrix. The output is a group of search-engine returned citations, such that the citations in each group …