Digital Commons Network^™

Relationship Analysis : Improving The Systems Analysis Process, Joseph Thomas Catanio

Dissertations

A significant aspect of systems analysis involves discovering and representing entities and their inter-relationships. Guidelines exist to identify entities but do not provide a rigorous and comprehensive process to explicitly capture the relationship structure of the problem domain. Whereas, other analysis techniques lightly address the relationship discovery process, Relationship Analysis is the only systematic, domain-independent analysis technique focusing exclusively on a domain's relationship structure.

The quality of design artifacts, such as class diagrams, and development time necessary to generate these artifacts can be improved by first representing the complete relationship structure of the problem domain. The Relationship Analysis Model is …

Characterization Of Ultrathin Gate Dielectrics And Multilayer Charge Injection Barriers, Edwin M. Dons

Dissertations

Since the invention of the first integrated circuit, the semiconductor industry has distinguished itself by a phenomenally rapid pace of improvements in device performance. This trend of ever smaller and faster devices is a result of the ability to exponentially reduce feature sizes of integrated circuits, a trend commonly known as "scaling". A reduction of overall feature sizes requires a simultaneous reduction in the thickness of the gate dielectric, SiO₂, of a MOSFET. Gate oxides in the ultrathin regime (<35 A) feature a large direct tunneling leakage current. The presence of this leakage current requires a reevaluation of standard characterization techniques as well as a reevaluation of the continued usefulness of SiO₂ as the gate dielectric of choice for future applications. On the other hand, a thorough understanding of …

Performance Evaluation Of Communication Systems With Transmit Diversity, Chunjun Gao

Dissertations

Transmit diversity is a key technique to combat fading with multiple transmit antennae for next-generation wireless communication systems. Space-time block code (STBC) is a main component of this technique. This dissertation consists of four parts: the first three discuss performance evaluation of STBCs in various circumstances, the fourth outlines a novel differential scheme with full transmit diversity.

In the first part, closed-form expressions for the bit error rate (BER) are derived for STBC based on Alamouti's scheme and utilizing M-ary phase shift keying (MPSK) modulation. The analysis is carried out for a slow, flat Rayleigh fading channel with coherent detection …

A Discovery And Analysis Of Influencing Factors Of Pair Programming, Kyungsub Steve Choi

Dissertations

The exploration into the underlying psychosocial links of pair programming. a new and unorthodox programming paradigm in which two programmers share one keyboard and monitor during real-time programming sessions, is undertaken. These complex psychosocial relationships, along with cognitive process exchanges, ultimately mold the programming output as well as determine the level of communication, satisfaction. confidence and compatibility. Laying the framework for this research, a through review of traditional and contemporary paradigms with a special focus on their limitations and a list of current software development problems are presented. Next, a detailed summary of pair programming and related agile software paradigms, …

On Ip Over Wdm Burst-Switched Long Haul And Metropolitan Area Networks, Jingxuan Liu

Dissertations

The IP over Wavelength Division Multiplexing (WDM) network is a natural evolution ushered in by the phenomenal advances in networking technologies and technical breakthroughs in optical communications, fueled by the increasing demand in the reduction of operation costs and the network management complexity. The unprecedented bandwidth provisioning capability and the multi-service supportability of the WDM technology, in synergy with the data-oriented internetworking mechanisms, facilitates a common shared infrastructure for the Next Generation Internet (NGJ).

While NGI targets to perform packet processing directly on the optical transport layer, a smooth evolution is critical to success. Intense research has been conducted to …

Development Of Dynamic Recursive Models For Freeway Travel Time Predictions, Xiaobo Liu

Dissertations

Traffic congestion has been a major problem in metropolitan areas, which is caused by either insufficient roadway capacity or unforesceable incidents. In order to promote the efficiency of the existing roadway networks and mitigate the impact of traffic congestion, the development of a sound prediction model for travel times is desirable.

A comprehensive literature review about existing prediction models was conducted by investigating the advantages, disadvantages, and limitations of each model. Based on the features and properties of previous models, the base models including exponential smoothing model (ESM), moving average model (MAM), and Kalman filtering model (KFM) are developed to …

A Gibbs Sampling Approach To Maximum A Posteriori Time Delay And Amplitude Estimations, Michele Picarelli

Dissertations

Research concerned with underwater propagation in a shallow ocean environment is a growing area of study. In particular, the development of fast and accurate computational methods to estimate environmental parameters and source location is desired. In this work, only select features of the acoustic field are investigated, namely, the time delays and amplitudes of individual paths, the signal-to-noise ratio, and the number of multi-path arrivals. The amplitudes and delays contain pertinent information about the geometry associated with the environment of interest. Estimating the time delays and amplitudes of select paths in a manner that is both accurate and time efficient, …

Multi-Rate Access Schemes And Successive Interference Cancellation For Wireless Multimedia Mc-Cdma Communications, Mizhou Tan

Dissertations

To catch up with the fast changes of the information challenges, providing multimedia services has become a very important requirement for future wireless communications. A proper system, capable of supporting multi-rate transmissions as well as handling high quality of service (QoS) requirements in hostile wireless communication environments, should be sought. Multi-carrier CDMA (MC-CDMA), a combination of multi-carrier modulation (MCM) and direct-sequence CDMA (DS-CDMA), appears to be one of the most elegant solutions. In this dissertation, four multi-rate access schemes, termed uncoded fixed spreading length (UFSL), coded fixed spreading length (CFSL), multi-code fixed spreading length (MFSL) and variable spreading length (VSL), …

Boron And Phosphorous Implantation Into (100) Germanium : Modeling And Investigation Of Dopant Annealing Behavior, Yong Seok Suh

Dissertations

Germanium is increasingly being considered at this time for future silicon compatible optoelectronic and complementary metal oxide semiconductor (CMOS) device application. Germanium implantation will be a critical process for future device fabrication. However, critical properties like Pearson parameters and dopant activation temperatures are not well established. In this study, boron and phosphorus were implanted into (100) germanium with energies ranging from 20 to 320 keV and doses of 5 x 10¹³ to 5 x 10¹⁶ cm^-2. The behavior of the boron and phosphorus before and after annealing for 3 hours at 400, 600 or 800°C in …

Providing Guaranteed Qos In The Hose-Modeled Vpn, Dong Wei

Dissertations

With the development of the Internet, Internet service providers (ISPs) are required to offer revenue-generating and value-added services instead of only providing bandwidth and access services. Virtual Private Network (VPN) is one of the most important value-added services for ISPs.

The "classical" VPN service is provided by implementing layer 2 technologies, either Frame Relay (FR) or Asynchronous Transfer Mode (ATM). With FR or ATM, virtual circuits are created before data delivery. Since the bandwidth and buffers are reserved, the QoS requirements can be naturally guaranteed. In the past few years, layer 3 VPN technologies are widely deployed due to the …

Phase Noise Effects On Ofdm : Analysis And Mitigation, Songping Wu

Dissertations

Orthogonal frequency division multiplexing (OFDM) is a promising technique which has high spectrum efficiency and the robustness against channel frequency selectivity. One drawback of OFDM is its sensitivity to phase noise. It has been shown that even small phase noise leads to significant performance loss of OFDM. Therefore, phase noise effects on OFDM systems need to be analyzed and methods be provided to its mitigation.

Motivated by what have been proposed in the literature, the exact signal to interference plus noise ratio (SINR) is derived in this dissertation for arbitrary phase noise levels. In a multiple access environment with multiple …

Enhancing Qos Provisioning And Granularity In Next Generation Internet, Jie Yang

Dissertations

Next Generation IP technology has the potential to prevail, both in the access and in the core networks, as we are moving towards a multi-service, multimedia and high-speed networking environment. Many new applications, including the multimedia applications, have been developed and deployed, and demand Quality of Service (QoS) support from the Internet, in addition to the current best effort service. Therefore, QoS provisioning techniques in the Internet to guarantee some specific QoS parameters are more a requirement than a desire. Due to the large amount of data flows and bandwidth demand, as well as the various QoS requirements, scalability and …

Statistical Anomaly Denial Of Service And Reconnaissance Intrusion Detection, Zheng Zhang

Dissertations

This dissertation presents the architecture, methods and results of the Hierarchical Intrusion Detection Engine (HIDE) and the Reconnaissance Intrusion Detection System (RIDS); the former is denial-of-service (DoS) attack detector while the latter is a scan and probe (P&S) reconnaissance detector; both are statistical anomaly systems.

The HIDE is a packet-oriented, observation-window using, hierarchical, multi-tier, anomaly based network intrusion detection system, which monitors several network traffic parameters simultaneously, constructs a 64-bin probability density function (PDF) for each, statistically compares it to a reference PDF of normal behavior using a similarity metric, then combines the results into an anomaly status vector that …

Mobile Agent Based Distributed Network Management : Modeling, Methodologies And Applications, Jian Ye

Dissertations

The explosive growth of the Internet and the continued dramatic increase for all wireless services are fueling the demand for increased capacity, data rates, support of multimedia services, and support for different Quality of Services (QoS) requirements for different classes of services. Furthermore future communication networks will be strongly characterized by heterogeneity. In order to meet the objectives of instant adaptability to the users' requirements and of interoperability and seamless operation within the heterogeneous networking environments, flexibility in terms of network and resource management will be a key design issue. The new emerging technology of mobile agent (MA) has arisen …

Ad Hoc Network Security And Modeling With Stochastic Petri Nets, Congzhe Zhang

Dissertations

Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. These networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. Unlike the existing commercial wireless systems and fixed infrastructure networks, they do not rely on specialized routers for path discovery and traffic routing. Security is an important issue in such networks. Typically, mobile nodes are significantly more susceptible to physical attacks than their wired counterparts.

This research intends to investigate the ad hoc network routing security by proposing a performance …

Uncertainty Analysis In Ecological Risk Assessment Modeling, Tepwitoon Thongsri

Dissertations

A probabilistic approach employing Monte Carlo simulations for assessing parameter and risks as probabilistic distributions was used in an ecological risk assessment (ERA) model to characterize risk and address uncertainty. This study addresses the following sources of uncertainty: parameter inputs in the ERA models, risk algorithms and uncertain input concentrations. To achieve this objective, both sensitivity and uncertainty analyses are being conducted. Monte Carlo simulations were used for generating probabilistic distributions of parameter and model uncertainty. All sensitivity, uncertainty, and variability analyses were coded in Visual Basic as part of the ERA model software version 2001, which was developed under …

Qos Provisioning In Multimedia Streaming, Hong Zhao

Dissertations

Multimedia consists of voice, video, and data. Sample applications include video conferencing, video on demand, distance learning, distributed games, and movies on demand. Providing Quality of Service (QoS) for multimedia streaming has been a difficult and challenging problem. When multimedia traffic is transported over a network, video traffic, though usually compressed/encoded for bandwidth reduction, still consumes most of the bandwidth. In addition, compressed video streams typically exhibit highly variable bit rates as well as long range dependence properties, thus exacerbating the challenge in meeting the stringent QoS requirements of multimedia streaming with high network utilization. Dynamic bandwidth allocation in which …

Ultra-Wideband Technology For Short-Range Wireless Communication, Li Zhao

Dissertations

The ultra-wideband (UWB) radio core idea is to open large amounts of spectrum to a variety of users with little mutual interference between them. While ultra-wideband is being championed by several commercial companies, this technology has not followed the conventional path where commercial interest is preceded by years of academic research. This work attempts to fill in some of the gap by studying fundamental properties of communications with impulse-based radio UWB signals. We study jam resistance and capacity of UWB. Jam resistance is analyzed for binary pulse position modulation (PPM) with the interference being modeled as correlated Gaussian. Closed-form expressions …

Transmission And Detection For Space-Time Block Coding And V-Blast Systems, Lei He

Dissertations

This dissertation focuses on topics of data transmission and detection of space -time block codes (STBC). The STBCs can be divided into two main categories, namely, the orthogonal space-time block codes (OSTBC) and the quasi-orthogonal space-time codes (Q-OSTBC). The space-time block coded systems from transceiver design perspective for both narrow-band and frequency selective wireless environment are studied. The dissertation also processes and studies a fast iterative detection scheme for a high-rate space-time transmission system, the V-BLAST system.

In Chapter 2, a new OSTBC scheme with full-rate and full-diversity, which can be used on QPSK transceiver systems with four transmit antennas …

Hybrid Routing And Bridging Strategies For Large Scale Mobile Ad Hoc Networks, Sheng Xu

Dissertations

Multi-hop packet radio networks (or mobile ad-hoc networks) are an ideal technology to establish "instant" communication infrastructure for military and civilian applications in which both hosts and routers are mobile. In this dissertation, a position-based/link-state hybrid, proactive routing protocol (Position-guided Sliding-window Routing - PSR) that provides for a flat, mobile ad-hoc routing architecture is described, analyzed and evaluated. PSR is based on the superposition of link-state and position-based routing, and it employs a simplified way of localizing routing overhead, without having to resort to complex, multiple-tier routing organization schemes. A set of geographic routing zones is defined for each node, …

Enriching And Designing Metaschemas For The Umls Semantic Network, Li Zhang

Dissertations

The disparate terminologies used by various biomedical applications or professionals make the communication between them more difficult. The Unified Medical Language System (UMLS) of the National Library of Medicine (NLM) is an attempt to integrate different medical terminologies into a unified representation framework to improve decision making and the quality of patient care as well as research in the health-care field. Metathesaurus (META) and Semantic Network (SN) are two main components of the UMLS system, where the SN provides a high-level abstract of the concepts in the META.

This dissertation addresses three problems of the SN. First, the SN's two-tree …

Organizational Structure And The Creative Process, Edward C. Bowen Edd

Dissertations

A creative edge can be a powerful source of competitive advantage in business, in war, in the arts, in science, and in life. In fact, creativity, innovation and the ability to adapt and change organizational structures in response to an increasingly fast-paced and competitive business environment are increasingly seen as essential for the success of many organizations. A current trend in organizational theory associates increases in formalization and both horizontal and vertical integration with decreases in an organization's ability to innovate and adapt. Consequently, organizational change efforts often involve moving from traditional, hierarchical structures toward flatter, more flexible types of …

What Effect Does The Hampton Inn 100% Unconditional Satisfaction Guarantee Have On Customer Loyalty?, Jeffrey Alan Carlstead Edd

Dissertations

Trust has been identified as a key factor in sustaining customer loyalty in service sector industries. The Hampton Inn hotel chain attempts to promote trust and loyalty among its customers by offering a 100% unconditional satisfaction guarantee. The purpose of this study was to investigate the extent to which a specific value-enhancing feature—the 100% unconditional guarantee—is likely to influence customer loyalty. In this study, loyalty was defined in two ways: (a) the likelihood of returning to another Hampton Inn property and (b) the likelihood of returning to the particular Hampton Inn at which this study was conducted. In the study, …

Total Resource Sharing Among Collegiate And Public Libraries In The Commonwealth Of The Northern Mariana Islands: A Narrative Case Study, Jimmie L. Ellis Edd

Dissertations

Especially in difficult economic times, educational and public sector organizations are under pressure to do more with less. At times, this means consolidating organizations to avoid costly duplication. This study focused on three attempts at consolidation that occurred on the island of Saipan and the two major outer islands of the Commonwealth of the Northern Mariana Islands (CNMI). These efforts entailed total resource sharing across the collegiate and public libraries on these islands. Total resource sharing among the collegiate and public libraries in the CNMI was first envisioned in the late 1980s and early 1990s. By 1994, the concept of …

Wresting And Arresting Sense In Academe: The Complicated Discursive Structures Of Female Assistant Professors, Alana M. Nicastro Edd

Dissertations

Women in academe often become entangled in an intricate equation of sensemaking as they work to balance the professional demands of teaching, research, and service, while at the same time learning the political and moral meanings of being a scholar. Structuration theory offers avenues for closely examining communicative strategies women utilize to navigate their roles as assistant professors. Through intensive interviews with seven female assistant professors this research investigates their process of wresting and arresting sense of the complicated roles, rules, and structures in academe. Analysis of interview data reveals the multiple discourses that frame organizational practices that facilitate and …

The Relationship Between Leadership Styles And Labour Disputes In British Columbia's Public Schools, Yanping Wang Edd

Dissertations

For the last decade, adversarial relationships between teachers' associations and district administrators in the British Columbia public school system have been commonplace, frequently resulting in formal grievances and arbitration. Since dealing with these issues imposes enormous costs on both teachers' unions and school boards, this study used hierarchical regression analysis to explain why some schools have fewer grievances filed than other schools in the province. Specifically, this study used data gathered from 160 principals in the British Columbia public school system to examine the extent to which school demographics and principal leadership style helped explain variation in the rate of …

Nobody's Ever Asked Me That Before: Middle School Students Talk About Motivation To Achieve In School Contexts, Erika Daniels Edd

Dissertations

The purpose of this study was to explore whether or not a connection exists between students' school contexts and their academic and social choices by listening to the voices of first year middle school students. The intent of this study was to provide teachers with a way to reconceptualize adolescents as learners. Research suggests that there are two distinct approaches to the study of motivation. Some researchers believe that motivation can be externally enacted through exams, assessments, and other accountability measures. Other researchers believe that motivation is internally generated through the relationships students build, through their beliefs about learning, and …

An Examination Of Teachers’ Beliefs About Critical Reading And Academic Writing, Cindi Davis Harris Edd

Dissertations

The ability to compose a well-written research paper is evidence o f a student's ability to read critically and write academically. However, evidence suggests that many college-bound high school graduates have not learned these skills. While the research literature overwhelmingly supports the notion that teachers are an important factor in students’ academic success, and that in order to be academically successful, students need to have critical reading and writing skills, there has been little research about how teachers' beliefs and knowledge about critical reading and academic writing influence instruction with regard to these skills. This naturalistic case study employed in-depth …

Functioning Among Taiwanese Families With A Child Having Duchenne Muscular Dystrophy, Jih-Yuan Chen Phd, Msn, Rn

Dissertations

A cross-sectional study was designed to determine the factors with functioning among Taiwanese families with a child having Duchenne Muscular Dystrophy (DMD). This research investigated the level of a child's mobility upon family hardiness, functioning, and support from a family perspective. A total sample of 126 of participants was parents of children with DMD. Parents completed basic demographic information, the Family Assessment Device, Family Hardiness Index, Duke Health Profile, and Family APGAR. Pearson Correlation Coefficient test was performed to examine relationships between independent and dependent variables. To determine if the levels of child's mobility, family characteristics, family hardiness, family health, …

Cleaner Technologies As An Aspect Of Sustainable Tourism: Carribbean Case Studies, Fitzgerald J. Yaw Jr.

Dissertations

Tourists are becoming increasingly sophisticated in their selection of tourism destination. A major factor that has been gaining importance in their choice set is the environmental quality of their preferred destination. Tourism planners need to recognize that the sustainability of their destination and its various offerings necessitates the consideration of environmental protection and conservation-related issues. This dissertation undertakes the case study methodology to explore the link between implementing cleaner technologies, a major environmental issue, and sustainable tourism.

The Caribbean is a region in the world that is strongly dependent on tourism for its economic development. Thus the analysis of how …