Call number: LD2668 .T4 1985 H87 / Master of Science

The purpose of this study was to design a model to evaluate the influence of selected factors on the performance of a telephone delivery system for nutrition information and use the model to evaluate the performance of the Roanoke Dietetic Association Dial-A-Dietitian program. The Dial-A-Dietitian program was established to provide nutrition information to the public by Registered Dietitians. The model entailed a systems approach to evaluate the Roanoke Dietetic Association Dial-A-Dietitian program. The five phases of the model included Enabling Factors (inputs), the Interaction Process, Effort Factors (outputs), Performance (outcome), and Feedback. Feedback entailed the utilization of the results of the evaluation in the decision-making process for future Dial-A-Dietitian programs and their operation. The evaluation instruments, the Encounter Form and the Telephone Survey of clients, included reaction statements and attitude assessment of clients and dietitians. The data were analyzed with frequency distributions. Also the Chi Square Tests of Independence were computed to determine the relationship between the independent variables, Enabling Factors (Phase 1) and Effort Factors (Phase 3), and the dependent variable, Performance (Phase 4). The model was useful in the evaluation of the Dial-A-Dietitian program. The data analysis indicated that the Dial-A-Dietitian program was effective as measured by this model. / Ph. D.

In this dissertation, the accuracy and reliability of non-linear finite element computations in application to surgical simulation is evaluated. The evaluation is performed through comparison between the experiment and finite element analysis of indentation of soft tissue phantom and human brain phantom. The evaluation is done in terms of the forces acting on the cylindrical Aluminium indenter and deformation of the phantoms due to these forces. The deformation of the phantoms is measured by tracking 3D motions of X-ray opaque markers implanted in the direct neighbourhood under the indenter using a custom-made biplane X-ray image intensifiers (XRII) system. The phantoms are made of Sylgard® 527 gel to simulate the hyperelastic constitutive behaviour of the brain tissue. The phantoms are prepared layer by layer to facilitate the implantation of the X-ray opaque markers. The modelling of soft tissue phantom indentation and human brain phantom indentation is performed using the ABAQUSTM/Standard finite element solver. Realistic geometry model of the human brain phantom obtained from Magnetic Resonance images is used. Specific constitutive properties of the phantom layers determined through uniaxial compression tests are used in the model. The models accurately predict the indentation force-displacement relations and marker displacements in both soft tissue phantom indentation and human brain phantom indentation. Good agreement between the experimental and modelling results verifies the reliability and accuracy of the finite element analysis techniques used in this study and confirms the predictive power of these techniques in application to surgical simulation.

High performance computer clusters have become popular as they are more scalable, affordable and reliable than their centralized counterparts. Database management systems are particularly suitable for distributed architectures / however distributed DBMS are still not used widely because of the design difficulties. In this study, we aim to help overcome these difficulties by implementing a simulation testbed for a distributed query plan processor. This testbed works on our departmental HPC cluster machine and is able to perform select, project and join operations. A data generation module has also been implemented which preserves the foreign key and primary key constraints in the database schema. The testbed has capability to measure, simulate and estimate the response time of a given query execution plan using specified communication network parameters. Extensive experimental work is performed to show the correctness of the produced results. The estimated execution time costs are also compared with the actual run-times obtained from the testbed to verify the proposed estimation functions. Thus, we make sure that these estimation iv functions can be used in distributed database query optimization and distributed database design tools.

Multicasting is a technique used for distributing data packets from one or more sources to a set of receivers on interconnected networks. Currently developing network applications bring specific quality of service (QoS) requirements like bounded delay, minimum bandwidth, and maximum data loss rate. Providing the required quality of service addresses routing and resource reservation concepts. In this study, a literature survey is carried out on traditional and QoS multicast routing protocols, and the need for QoS routing protocols is investigated. QoS multicast routing protocols are classified and compared according to their multicast tree construction and resource reservation approaches. Two QoS protocols, QROUTE and QMBF, are selected, and their performances are experimentally compared using the network simulation tool Network Simulator-2 (ns-2). The objective of the simulations is to compare the QoS routing algorithms and their tree construction efficiencies. The first contribution of the thesis is the survey and classification of traditional and QoS multicast routing protocols. Another contribution is the ns-2 implementation of two QoS multicast routing protocols. The final contribution of the thesis is the performance evaluation of the recent protocols from a different perspective.

This thesis is a study of multiple access schemes for satellite land mobile systems that provide a domestic or regional service to a large number of small terminals. Three orbit options are studied, namely the geostationary, elliptical (Molniya) and inclined circular orbits. These are investigated for various mobile applications and the choice of the Molniya orbit is justified for a U. K. system. Frequency, Time and Code Division Multiple Access (FDMA, TDMA and CDMA) are studied and their relative merits in the mobile environment are highlighted. A hybrid TDMA/FDMA structure is suggested for a large system. Reservation ALOHA schemes are appraised in a TDMA environment and an adaptive reservation multiple access protocol is proposed and analysed for a wide range of mobile communication traffic profiles. The system can cope with short and long data messages as well as voice calls. Various protocol options are presented and a target system having 100,000 users is considered. Analyses are presented for the steady state of protocols employing pure and slotted ALOHA and for the stabilty of the slotted variant, while simulation techniques were employed to validate the steady state analysis of the slotted ALOHA protocol and to analyse the stability problem of the pure ALOHA version. An innovative technique is put forward to integrate the reservation and the acquisition processes. It employs the geographical spread of the users to form part of the random delay in P-ALOHA. Finally an economic feasibility study is performed for the spacesegment. For costs of capital (r) less than 23 % the discounted payback period is less than the project's lifetime (10 years). At r- 8% the payback period is about 5.6 years, while the internal-rate-of-return is 22.2 %. The net present value at the end of the projects lifetime is £M 70 at r-8%.

The graduation thesis deals with the evaluation of the individual entrepreneur's business plan. To decide whether a project is accepted or not, was drawn up a detailed business plan, sometimes referred to as a feasibility study. The theoretical part discusses the purpose of the business plan, elaborates on the basic essentials of the business plan, the form and the principles of treatment. Based on a synthesis of findings from the literature the author further elaborates on some of the tools of managerial and economic practises and their applicability in the business plan. The aim of the theoretical part is inter alia to provide guidance to anyone who is processing the business plan without necessity of studying comprehensive literature. The practical part already specifically deals with author's business plan. On its basis it should be possible to decide whether to implement the plan. It is specific narrowly focused Internet project. The methods used to evaluate the project revealed the potential of the project and simultaneously pointed out to the potential risks. The entire business plan then finds the image in the used modern approach to the evaluation of investment projects -- the Monte Carlo simulation.

Un environnement spatial naturel hostile, les systèmes spatiaux de télédétection traditionnels,monolithiques et téléopérés depuis le sol, demeurent vulnérables face à un nombre croissant de menaces émergentes issues de l’environnement spatial artificiel (armes antisatellites,débris). Plutôt que de chercher à protéger physiquement les satellites, nous proposons d’adopter une stratégie fondée sur le concept de résilience, qui traduit la capacité d’un système à poursuivre sa mission face à des aléas imprévisibles, fût-ce en mode dégradé. En nous appuyant sur de récentes innovations dans les technologies spatiales, nous nous sommes intéressés à la conception et à l’évaluation d’architectures système fondées sur la mise en réseau de constellations de microsatellites hétérogènes, autonomes et communicants.Afin d’étudier de telles architectures, appelées réseaux de constellations autonomes (RCA),nous proposons une approche de modélisation ainsi qu’un outil de simulation à base de réseaux de Petri imbriqués. Grâce à des métriques issues des réseaux de télécommunication ainsi que des systèmes multiagents, nous avons évalué les RCA au travers de leurs performances opérationnelles et de leurs capacités de communication, nominales puis dans divers modes dégradés. Du point de vue de la résilience, les résultats présentés mettent en évidence l’intérêt de disposer de réseaux de communication denses et de modules de reconfiguration autonomes embarqués au sein même des satellites. / Although Earth observation space systems are designed with strong safety requirements due to an hostile natural space environment, they remain vulnerable to an increasing range of emerging space threats such as antisatellite weapons or orbital debris. Instead of a physical protection of these monolithic and remote-controlled assets, we propose a design strategy based on the concept of resilience which is the ability of a system to maintain an acceptable level of performance in the presence of unforeseeable disturbance.Thanks to the latest space technology innovations, we devised new system architectures composed of networked constellations of heterogeneous and autonomous interacting microsatellites. We decided to model these architectures, called autonomous networked constellations (RCA in French), thanks to Petri nets, and more specifically their nets-within-nets variant. Using telecommunication and multiagent metrics, we assessed different RCA configurations through their operational performance and communicability, for nominal as wellas degraded modes. From the resilience point of view, we present quantitative results that point out the benefits of dense space networks and embedded autonomous reconfiguration modules.

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