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This thesis describes a procedure to measure the transient effects in a fuel cell air delivery system. These methods were applied to model the 20 kW automotive fuel cell system that was used in Animul H2, a fuel cell-battery hybrid sedan developed by a group of engineering students at Virginia Tech. The air delivery system included the air compressor, the drive motor for the compressor, the motor controller, and any plumbing between the fuel cell inlet and the compressor outlet. The procedure was to collect data from a series of tests of the air delivery system with no load (zero outlet pressure) and at several loads. The air compressor speed, outlet pressure, and motor controller current were measured in response to a variety of speed requests. This data was fit to transfer functions relating the compressor speed, outlet pressure, or motor controller current to the speed request. The fits were found using a least squares optimization technique. After the experimental model was developed, it was augmented with an analytical model of the rest of the fuel cell system. The mass flow of the air was determined from the air compressor speed and outlet pressure with the compressor map. The fuel cell current was found by assuming a constant stoichiometric ratio. The power out of the fuel cell was calculated from the fuel cell current and the pressure with the polarization curve. The model of the fuel cell system was implemented in Matlab/Simulink. Several open and closed loop simulations were run to test the functionality of the fuel cell system model. The gross and net powers of the fuel cell system were found as a function of the compressor operating speed. The time it took for the system to come up to power as a function of idle speed was also found. A PID controller was implemented to allow the system to track a reference power request. The key contributions of this work were to develop a method to test the air delivery system to determine the dynamics of the system, to develop a model based on these tests and some analytical knowledge of fuel cells, and to use the model to simulate the operation and control of a fuel cell system. / Master of Science

<p>Iako se poslednjih godina sve veća paţnja<br />pridaje tehnikama odrţavanja na bazi rizika, i<br />metode tehniĉke dijagnostike implementiraju<br />u sve većem obimu, a dizalice, kao grupa<br />naj&scaron;ire primenjenih sredstava u rukovanju<br />materijalima, uĉestvuju sa ĉak jednom<br />trećinom u svim smrtnim sluĉajevima<br />pojedinih grana industrije, razvoj modela<br />odrţavanja konkretnih tehniĉkih sistema van<br />polja nuklearne i petrohemijske industrije ne<br />napreduje dovoljno brzo. Shodno tome,<br />predmet disertacije je postavka i potvrda<br />dovoljno taĉnog i dovoljno jednostavnog<br />modela odrţavanja sistema dizaliĉnog<br />transporta za &scaron;iru industrijsku primenu.<br />Novopostavljen model odrţavanja sistema<br />dizaliĉnog transporta, sadrţi dva modula -<br />tehniĉki i &bdquo;menadţment― modul. Shodno<br />predloţenom tehniĉkom modulu modela<br />odrţavanja sistema dizaliĉnog transporta,<br />sprovedena je eksperimentalna provera<br />tehniĉkog modula modela in site na dva<br />sistema dizaliĉnog transporta na<br />hidroelektrani &bdquo;HE Đerdap 1― u Kladovu kao<br />i provera faktora &bdquo;menadţment― modula<br />primenom metoda statistiĉke analize<br />(faktorska i analiza pouzdanosti) na uzorku 51<br />preduzeća u cilju dobijanja modifikacionog<br />faktora. Vrednosti modifikacionog faktora<br />odredjuju zahvat tehniĉkog faktora (postupak<br />procene tehniĉkog faktora u celini, vizuelna<br />kontrolu stanja konstrukcije i mehanizama<br />dizalica i statiĉki i dinamiĉki proraĉun modela<br />konstrukcije dizalica ili samo vizuelna<br />kontrola).</p> / <p>Although in recent years, more attention is<br />given to risk-based techniques of<br />maintenance, and methods of technical<br />diagnostics are implemented in an increasing<br />extent, and cranes, as a group of the most<br />widely used resources in material handling,<br />account for one third of all deaths in certain<br />industries, development of specific<br />maintenance models of technical systems<br />outside the field of nuclear and petrochemical<br />industries is not progressing fast enough.<br />Accordingly , the subject of this dissertation is<br />the setting and confirmation of sufficiently<br />accurate and sufficiently simple maintenance<br />model for cranes system transportation for<br />general industrial applications. The newly<br />appointed maintenance model for cranes<br />system transportation, contains two modules -<br />technical and &quot;management&quot; module.<br />According to the proposed technical module<br />of maintenance model for cranes system<br />transportation the experimental verification is<br />carried out on the two cranes systems in<br />power plant &quot;Djerdap 1 &quot; in Kladovo while<br />&#39;management&#39; module factors are proved using<br />the methods of statistical analysis ( factor<br />analysis and reliability) on the sample sized<br />51 in order to obtain the modification factor.<br />The values of modification factor determine<br />the level of technical factors needed (process<br />evaluation of technical factors as a whole, the<br />visual control condition of the structure and<br />mechanisms of cranes and static and dynamic<br />analysis model construction crane or solely<br />visual inspection).</p> / null

The fundamental character of excitation system is to provide the direct-current power for field windings for synchronous generators. Excitation control system controls the generator output voltage and reactive power by varying the field winding¡¦s currents. Therefore, it can improve the transient stability of power system. The thesis proposed a process for modeling and simulation on a brushless coal-fired unit, since the 40 years-old magnetic amplifier (Type WMA MAG-A-STAT) Automatic Voltage Regulator (AVR) was replaced by a Programmable Logical Controller based digital redundancy system, for the purpose to verify the excitation system model and dynamic response gains in the future power system study. To establish the generator excitation system and simulations on a popular software program MATLAB/SIMULINK, we wish to manipulate the effective and precise simulation test on a personal-computer and apply Particle Swarm Optimization (PSO) to find the global optimal solution for AVR controller settings. This thesis contributes in building a reliable excitation system model with dynamic response figures for power system network planning and dispatch.

Critically ill patients are known to experience stress-induced hyperglycemia. Inhibiting the physiological response to increased glycaemic levels in these patients are factors such as increased insulin resistance, increased dextrose input, absolute or relative insulin deficiency, and drug therapy. Although hyperglycemia can be a marker for severity of illness, it can also worsen outcomes, leading to an increased risk of further complications. Recent studies have shown that tight control can reduce mortality up to 43%. Metabolic modelling has been used to study physiological behaviour and/or to control glycaemia for a long time and many successful approximate system models have been developed. Due to the malfunction of medical equipments, clinical measurements obtained usually come with noise. In addition, the few such systems currently available can have errors in excess of 20-30%. Therefore, to fully simulate the clinical data, the system model also needs to couple with a successful noise model. This research has developed a new noise model that better fits the current available statistical description of the noise profile and therefore can be applied to achieve better simulation results. The research also designed a filter algorithm that is capable of reducing the sensor measurement error down to an acceptable value. Achieving such a goal is a significant step towards fully automated adaptive control of hyperglycaemia in critically ill patients and would therefore reduce mortality.

Historically, managing access to information systems (ISs) required direct interaction with a limited number of users. Increasingly, managing access involves handling an increased numbers of internal and external students, faculty, and staff as well as partners such as workforce development centers, the U.S. Department of Education, and the Council on Higher Education Accreditation. At Minnesota State Colleges and Universities (MnSCU), the approach to identity management (IdM) required the distribution of a username and password to authenticate MnSCU employees and students. Authentication enables authorized users to access campus-supported ISs and Office of the Chancellor (OOC) supported ISs such as the Integrated Statewide Record System (ISRS). In some cases, an MnSCU employee or student will receive as many as 7 usernames and passwords. When a new employee or student joins MnSCU, the campus IT group creates a general log-on to campus-supported ISs. This log-on consists of a username and password and provides the new employee or student with access to a local area network (LAN) hosted application such as e-mail and campus directory services. The author used Minnesota State College-Southeast Technical (MSC-ST) as the unit of analysis. In this inquiry, the following propositions guided and shaped the case study data collection: (a) system development processes (SDPs), (b) single access sign-on credentials through all MSC-ST ISs, (c) electronic data assurances, and (d) implementation across public and private security zones. The findings from this case study were used to develop a paradigm supporting the design and development of an IdM system model at MSC-ST. This model contributed to the establishment of a uniform IdM system for use by MSC-ST students, staff, and faculty regardless of time and location. Based on findings from this case study, key processes involved in establishing this IdM system based on uniform identities and authentication processes were documented. Key steps involved in facilitating secure IS access to MSC-ST resources by students, staff, and faculty accessing OOC-supported ISs as well as MSC-ST campus-specific applications were described. The author contributed to advancements in the IS space through the use of a replicable approach for implementing an IdM paradigm at MSC-ST.

The basis of success of today's organization can be determined by their ability to win contracts and fulfil the requirements of these contracts satisfactorily within the time scale agreed. For non-manufacturing project oriented organization it is important to obtain the optimal number of projects and to have sufficient human resources to carry out the work efficiently. This thesis aims to a possible solution for the bidding policy and optimal use of human resources in project oriented-organizations within the legislative environment of the Czech Republic. It is trying to find and recommend appropriate solutions of fluctuations in the need for human resources by using a system dynamics approach (developed model and its testing).

The land ecosystems in northern high latitudes (>45° N) occupy 22% of the global surface and store more than 1600 Pg soil organic carbon. Warming in this region has been documented during the past decades. Warming-induced changes in regional carbon dynamics are expected to loom large in the global carbon cycle and exert large feedbacks to the global climate system. Numerous Earth System Models have been widely used to quantify the response of terrestrial ecosystem carbon dynamics to climatic changes. However, predictions of terrestrial ecosystem carbon responses to increasing levels of atmospheric carbon dioxide (CO2) and climate change is still uncertain due to model limitations. The limitations include relatively low levels of representation of ecosystem processes that determine the exchanges of water, energy, and carbon between land ecosystems and the atmosphere and omitting some key biogeochemical mechanisms. To improve model realism and provide a better projection of the Arctic carbon dynamics, this dissertation developed three new versions of a process-based biogeochemistry models that involve more fundamental processes of terrestrial ecosystems. First, microbial dynamics and enzyme kinetics that catalyze soil carbon decomposition have been incorporated into the extant terrestrial ecosystem model TEM to remedy the inadequate representation of soil decomposition process. Furthermore, a vital microbial life-history trait, microbial dormancy, has been implemented into previous microbial-based model to consider the impacts of microbial dormancy in modeling. Additionally, the role of moss in the Arctic terrestrial ecosystem carbon quantification was also demonstrated by incorporating moss and higher plant interactions in modelling.

Cette thèse rappelle les fondements du pilotage des systèmes logistiques et montre l'intérêt de la mise en place d'un SCP (Systèmes Contrôlés par le Produit). L'intégration de tels systèmes doit d'abord prendre en compte la cohérence entre les différents éléments le constituant. Ainsi les systèmes centralisés cherchent à proposer des plans de moyen-long termes visant un optimal de coût, mais aussi une certaine stabilité et peu de nervosité dans le temps. Par ailleurs, les systèmes distribués ont démontré leur capacité à permettre une réaction rapide à des événements impromptus survenant dans le système physique. L'hybridation de ces deux types de pilotage est donc une voie de gain de productivité pour les systèmes logistiques et industriels. Le premier chapitre de la thèse décrit l'évolution des systèmes de planification et de pilotage de la production, avec l'objectif d'identifier les forces et faiblesses des différentes approches proposées jusqu'à nos jours et permettent définir l'objectif général de la thèse. Le chapitre deux analyse l'état de l'art concernant les outils de modélisation des systèmes de production centralisés/distribués et aussi le concept de contrôle par le produit. Ce chapitre sert de base pour définir les objectifs spécifiques de la thèse. Le chapitre trois présente le cadre de modélisation proposé. Ce cadre est basé sur une approche cybernétique, et plus spécifiquement sur le modèle de système viable (VSM). Le chapitre démarre avec une présentation générale du modèle de système viable, puis présente un modèle générique de modélisation de systèmes contrôlés par le produit. Enfin, le chapitre décrit une application de ce cadre général aux systèmes de planification et pilotage de la production de type SCP. Le chapitre quatre définit les différentes méthodes de décision, tant centralisées que distribuées, développées pour l'implémentation du modèle générique définit dans le chapitre trois. Aux niveaux centralisés et distribués ces méthodes sont basées sur des modèles de programmation mathématique développés pour considérer l'adaptabilité et la flexibilité du système. Le chapitre cinq montre les principaux résultats dans une application basée sur un cas industriel qui a nécessité le développement d'un outil de simulation qui considère des variables de court, moyen et long termes pour les différents modèles d'optimisation. Ces résultats montrent l'intérêt de ce type d'hybridation / This thesis is concerned with the foundations of the planning and control logistics systems and shows the interest of the PDS (Product-driven Systems) applied in this context. The development of such systems must consider the coherence between the different components. Centralized systems offer long terms plans aiming an optimal cost, but also some stability and nervousness reduction. Distributed systems allow a fast reaction to perturbations happening in the physical system. Then, the hybridization of these two kinds of planning and control systems is a way of increase productivity for logistic and industrial systems. The first chapter of the thesis describes the evolution of the production planning and control systems, to identify forces and weaknesses of the different approaches proposed until our days and allow to define the general objective of the thesis. Chapter two analyses the state of the art concerning the tools for modeling hybrid centralized/distributed production systems and also the concept of product-driven systems. This chapter serves as a basis to define the specific objectives of the thesis. Chapter three introduces the proposed modeling framework. This framework is based on a cybernetic approach, and more specifically in the Viable System Model (VSM). The chapter starts with a general presentation of VSM and then introduces a generic framework to model PDS. Finally, this chapter describes an application for production planning and control. Chapter four defines the different decision methods developed for the implementation of the generic model defined in the chapter three. At centralized and distributed levels these methods are based on mathematical programming models. Chapter five shows the main results of an application based on an industrial case which required the development of a simulation tool which considers variables of short, médium and long terms for the different optimization models. These results show the interest of this type of hybridization