Dissertations / Theses on the topic 'Modelling and simulation in information systems'
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Eatock, Julie. "Dynamic integrated modelling of information systems and business process simulation." Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/5248.
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Business processes and information technology are two areas that are very closely related to the sustained competitive advantage in organisations. However, investment in information technology often leads to disappointment, which may in part be due to the non-alignment of the information system domain with the business process domain. Simulation modelling is an established technique often used in business process change projects, as it allows a comparison of different possible scenarios without the expense of physically implementing the system. However business process simulation fails to effectively capture the information systems perspective in the model. This thesis contends that by combining information systems modelling techniques with business process simulation the model will be able to capture all the four perspectives (functional, behavioural, organisational and informational) of an organisation, and the design of the business processes and the information system will be better aligned. Initially, attempts were made to integrate business process simulation with computer network simulation in a simple two- or three-layered simulation model, but this gave rise to significant problems the most significant being the underlying assumptions of the original hypothesis. This led to a refined hypothesis in which the layered models were discarded along with the network domain. The revised hypothesis aimed to capture the informational changes that occur in the information system and therefore combines prototyping with business process simulation. This overcomes the unsafe assumptions of the initial hypothesis about whether the system is 'correct' and provides a method of validating the design of the information system within the context of the business processes. The integrated model allows concurrent design of the information system domain and the business process domain and therefore ensures that the domains are better aligned. The framework is tested on a case study and the results indicate that it is an effective tool in the combined design of business processes and information systems.
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Serrano, Rico Alan Edwin. "Stochastic Information Technology Modelling for Business Processes." Thesis, Brunel University, 2002. http://bura.brunel.ac.uk/handle/2438/2035.
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Business Processes (BP) and Information Technology (IT) are two areas that work very closely in helping organisations to keep or retain competitive advantage. Therefore, design in these areas should consider the advantages provided by, and the limitations that each of these domains imposes on each other. BP design tries to ensure that IT specifications are considered during the design of BP. Similarly, Information Systems (IS) design attempts to capture organisational needs, known as IS functional and Non-Functional Requirements (NFR), in order to meet the organisational goals. Despite this, BP and IT modelling techniques barely depict the way IT may affect BP performance or vice versa. For example, Business Process Simulation (BPS) is one of the modelling techniques that has been increasingly used to support process design. The performance measurements obtained from BPS models, though, are obtained considering only organisational issues, and thus cannot be used to assess the impact that IT may have on process performance. Similarly, IT modelling techniques do not provide IS performance measurements, and hence cannot depict the way IS may improve BP performance. The relationship between BP and IT can be alternatively described in terms of the relationships between BP, IS and Computer Networks (CN). By looking at the parameters that govern these relationships a simulation framework was developed, namely ASSESS-IT, that develops simulation models that provide performance measurements of BP, IS and CN, and thus can reflect the impact that IT (IS and CN) may have on BP performance. This research uses a case study to test the proposed framework (theory testing), to understand the way BP, IS, and CN domains interact (discovery), and to propose alternative theories to solve the problems found (theory building). The experimentation with the ASSESS-IT framework suggests that in order to portray the impact that IT may have on BP, analysts in these domains should first identify those performance specifications that describe how well the IS delivers its functionality (also known as non-functional requirements). It was found that when the IS does not depend on determined response time, the relationships between BP, IS and CN can be assessed using only the relationship between BP and IS. An alternative simulation framework, namely BPISS, is proposed to produce BPS models that provide performance measurements of BP and IS. Thus, BP and IT analysts can investigate the impact that a given IS design may have on BP performance, and identify a better BP and IS solution.
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Di, Domenica Nico. "Stochastic programming and scenario generation : decision modelling simulation and information systems perspective." Thesis, Brunel University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415936.
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Wang, Qian. "Modelling and simulation of integrated operational and information processing systems in manufacturing." Thesis, University of Sussex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394898.
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Hultberg, Ida. "Modelling and Simulation of Unknown Factors in Simulation Based Acquisition." Thesis, University of Skövde, Department of Computer Science, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-715.
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When a new product should be acquired, a model over its functionality is made. A quite new idea in the military area is to use simulations to find out what and how much to acquire. Since the product never has been on the market before it is hard to know how factors in the surroundings, like weather and other active objects, will affect it. Therefore these unknown factors that appear during the creation or acquiring of a new product need to be taken into consideration.
A literature study is performed about how modelling of simulations can be done, and how unknown factors can be considered when modelling a simulation. The study goes into if unknown factors are taken into consideration when modelling in the Process component in Simulation Based Acquisition (SBA). The result of this study shows that SBA facilitates in the process of finding and reducing unknown factors.
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Ghaffari, Abdolali. "Application of geographical information systems (GIS) and crop simulation modelling in sustainable agriculture." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312108.
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Ulriksson, Jenny. "Consistency management in collaborative modelling and simulation." Licentiate thesis, KTH, Microelectronics and Information Technology, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-571.
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The aim of this thesis is to exploit the technological capabilities of computer supported collaborative work (CSCW) in the field of collaborative Modelling and Simulation (M&S). The thesis focuses on addressing two main problems: (i) providing flexible means of consistency management in collaborative M&S, and (ii) the ability of providing platform and application independent services for collaborative M&S.
In this work, some CSCW technologies and how some of the concepts can be incorporated in a distributed collaborative M&S environment, have been studied. An environment for component based simulation development and visualization, which provides support for collaborative M&S, has been designed. Some consistency policies that can be used in conjunction with distributed simulation and the High Level Architecture (HLA) have been investigated. Furthermore, the efficient utilization of HLA and XML in combination, as the foundation of a CSCW infrastructure has been proved. Two consistency policies were implemented utilizing HLA, a strict and an optimistic, in the distributed collaborative environment. Their performance was compared to the performance of a totally relaxed policy, in various collaboration situations.
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Aramrattana, Maytheewat. "Modelling and Simulation for Evaluation of Cooperative Intelligent Transport System Functions." Licentiate thesis, Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:vti:diva-12683.
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Future vehicles are expected to be equipped with wireless communication technology, that enables them to be “connected” to each others and road infrastructures. Complementing current autonomous vehicles and automated driving systems, the wireless communication allows the vehicles to interact, cooperate, and be aware of its surroundings beyond their own sensors’ range. Such sys- tems are often referred to as Cooperative Intelligent Transport Systems (C-ITS), which aims to provide extra safety, efficiency, and sustainability to transporta- tion systems. Several C-ITS applications are under development and will require thorough testing and evaluation before their deployment in the real-world. C- ITS depend on several sub-systems, which increase their complexity, and makes them difficult to evaluate. Simulations are often used to evaluate many different automotive applications, including C-ITS. Although they have been used extensively, simulation tools dedicated to determine all aspects of C-ITS are rare, especially human factors aspects, which are often ignored. The majority of the simulation tools for C-ITS rely heavily on different combinations of network and traffic simulators. The human factors issues have been covered in only a few C-ITS simulation tools, that involve a driving simulator. Therefore, in this thesis, a C-ITS simulation framework that combines driving, network, and traffic simulators is presented. The simulation framework is able to evaluate C-ITS applications from three perspectives; a) human driver; b) wireless communication; and c) traffic systems. Cooperative Adaptive Cruise Control (CACC) and its applications are chosen as the first set of C-ITS functions to be evaluated. Example scenarios from CACC and platoon merging applications are presented, and used as test cases for the simulation framework, as well as to elaborate potential usages of it. Moreover, approaches, results, and challenges from composing the simulation framework are presented and discussed. The results shows the usefulness of the proposed simulation framework.
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Kessels, Henricus. "Wildfire Management in the Southside Region of Canada’s Montane Cordillera - A Systems Modelling Application on Firebreak Strategies." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35107.
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There is growing recognition of the importance of preserving Canada’s forests. Canada’s 348 million hectares of forest land cover 35% of its land area, representing 9% of the world’s forests and 24% of the world’s boreal forests. As a renewable resource, forests offer significant environmental, economic and recreational benefits and innumerable services contributing to the quality of life.
Canada has recently entered an era of increased frequency and severity of natural disasters. Ecosystems and communities especially in western Canada have recently undergone a trend of increasing pressures from natural disturbances. These disturbances include wildfires associated with increased fuel load levels from past fire suppression regimes and a widely spread infestation of the mountain pine beetle in addition to changes in weather patterns. Wildfire activity has reached extreme levels in many of the recent years.
This thesis profiles an area of western Canada within the Montane Cordillera covering the Nechako Lakes Electoral District in central British Columbia and assesses its vulnerability to the specific hazard of wildfires caused by natural and man-made sources. The objectives of this research are to review, simulate and assess the impact of various fuel management strategies in a sub-section of the Nechako Lakes Electoral District called the Southside. Values at risk include private property and old growth forest in respectively timber supply areas, provincial parks, woodlots and community forests.
Simulation results show that firebreaks are effective in significantly reducing the area burned in different parts of the landscape. The performance of different strategies shows large variation. Although this has not been investigated further, such variation has likely been caused by topographic aspects and the positioning of firebreaks in the landscape in relation to climatic parameters. These results can therefore not be extrapolated beyond the simulated area, but do give an indication of the performance variation that may be expected when similar firebreaks are applied elsewhere. The results also show that model performance of all firebreak strategies is heavily and fairly consistently influenced by weather stream parameters. Sensitivity analyses of weather stream parameters show that although the reduction in total area burned varies, the ranking between strategies in their overall performance is consistent regardless of the weather pattern. Combined dry, warm and windy weather conditions lead to a 3.44-fold increase in total area burned as compared to the scenario with average weather conditions. In favourable weather conditions represented by wet, cold and nearly windless conditions, the model shows an 85% reduction in total burned area as compared to the average scenario. These results illustrate the significant impact of uncontrollable variables on the overall result.
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Gustafsson, Magnus. "Evaluation of StochSD for Epidemic Modelling, Simulation and Stochastic Analysis." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-426227.
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Classical Continuous System Simulation (CSS) is restricted to modelling continuous flows, and therefore, cannot correctly realise a conceptual model with discrete objects. The development of Full Potential CSS solves this problem by (1) handling discrete quantities as discrete and continuous matter as continuous, (2) preserving the sojourn time distribution of a stage, (3) implementing attributes correctly, and (4) describing different types of uncertainties in a proper way. In order to apply Full Potential CSS a new software, StochSD, has been developed. This thesis evaluates StochSD's ability to model Full Potential CSS, where the points 1-4 above are included. As a test model a well-defined conceptual epidemic model, which includes all aspects of Full Potential CSS, was chosen. The study was performed by starting with a classical SIR model and then stepwise add the different aspects of the Conceptual Model. The effects of each step were demonstrated in terms of size and duration of the epidemic. Finally, the conceptual model was also realised as an Agent Based Model (ABM). The results from 10 000 replications each of the CSS and ABM models were compared and no statistical differences could be confirmed. The conclusion is that StochSD passed the evaluation.
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Komashie, Alexander. "Information-theoretic and stochastic methods for managing the quality of service and satisfaction in healthcare systems." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4402.
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This research investigates and develops a new approach to the management of service quality with the emphasis on patient and staff satisfaction in the healthcare sector. The challenge of measuring the quality of service in healthcare requires us to view the problem from multiple perspectives. At the philosophical level, the true nature of quality is still debated; at the psychological level, an accurate conceptual representation is problematic; whilst at the physical level, an accurate measurement of the concept still remains elusive to practitioners and academics. This research focuses on the problem of quality measurement in the healthcare sector. The contributions of this research are fourfold: Firstly, it argues that from the technological point of view the research to date into quality of service in healthcare has not considered methods of real-time measurement and monitoring. This research identifies the key elements that are necessary for developing a real-time quality monitoring system for the healthcare environment.Secondly, a unique index is proposed for the monitoring and improvement of healthcare performance using information-theoretic entropy formalism. The index is formulated based on five key performance indicators and was tested as a Healthcare Quality Index (HQI) based on three key quality indicators of dignity, confidence and communication in an Accident and Emergency department. Thirdly, using an M/G/1 queuing model and its underlying Little’s Law, the concept of Effective Satisfaction in healthcare has been proposed. The concept is based on a Staff-Patient Satisfaction Relation Model (S-PSRM) developed using a patient satisfaction model and an empirically tested model developed for measuring staff satisfaction with workload (service time). The argument is presented that a synergy between patient satisfaction and staff satisfaction is the key to sustainable improvement in healthcare quality. The final contribution is the proposal of a Discrete Event Simulation (DES) modelling platform as a descriptive model that captures the random and stochastic nature of healthcare service provision process to prove the applicability of the proposed quality measurement models.
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Tavakoli, Siamak. "A generic predictive information system for resource planning and optimisation." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/8116.
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The purpose of this research work is to demonstrate the feasibility of creating a quick response decision platform for middle management in industry. It utilises the strengths of current, but more importantly creates a leap forward in the theory and practice of Supervisory and Data Acquisition (SCADA) systems and Discrete Event Simulation and Modelling (DESM). The proposed research platform uses real-time data and creates an automatic platform for real-time and predictive system analysis, giving current and ahead of time information on the performance of the system in an efficient manner. Data acquisition as the backend connection of data integration system to the shop floor faces both hardware and software challenges for coping with large scale real-time data collection. Limited scope of SCADA systems does not make them suitable candidates for this. Cost effectiveness, complexity, and efficiency-orientation of proprietary solutions leave space for more challenge. A Flexible Data Input Layer Architecture (FDILA) is proposed to address generic data integration platform so a multitude of data sources can be connected to the data processing unit. The efficiency of the proposed integration architecture lies in decentralising and distributing services between different layers. A novel Sensitivity Analysis (SA) method called EvenTracker is proposed as an effective tool to measure the importance and priority of inputs to the system. The EvenTracker method is introduced to deal with the complexity systems in real-time. The approach takes advantage of event-based definition of data involved in process flow. The underpinning logic behind EvenTracker SA method is capturing the cause-effect relationships between triggers (input variables) and events (output variables) at a specified period of time determined by an expert. The approach does not require estimating data distribution of any kind. Neither the performance model requires execution beyond the real-time. The proposed EvenTracker sensitivity analysis method has the lowest computational complexity compared with other popular sensitivity analysis methods. For proof of concept, a three tier data integration system was designed and developed by using National Instruments’ LabVIEW programming language, Rockwell Automation’s Arena simulation and modelling software, and OPC data communication software. A laboratory-based conveyor system with 29 sensors was installed to simulate a typical shop floor production line. In addition, EvenTracker SA method has been implemented on the data extracted from 28 sensors of one manufacturing line in a real factory. The experiment has resulted 14% of the input variables to be unimportant for evaluation of model outputs. The method proved a time efficiency gain of 52% on the analysis of filtered system when unimportant input variables were not sampled anymore. The EvenTracker SA method compared to Entropy-based SA technique, as the only other method that can be used for real-time purposes, is quicker, more accurate and less computationally burdensome. Additionally, theoretic estimation of computational complexity of SA methods based on both structural complexity and energy-time analysis resulted in favour of the efficiency of the proposed EvenTracker SA method. Both laboratory and factory-based experiments demonstrated flexibility and efficiency of the proposed solution.
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Lol, Wilford Gibson. "An investigation of the impact of routing protocols on MANETs using simulation modelling a dissertation submitted to Auckland University of Technology in partial fufilment of the requirements for the degree of Master of Computer and Information Sciences, 2008 /." Click here to access this resource online, 2008. http://hdl.handle.net/10292/718.
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Thesis (MCIS - Computer and Information Sciences) -- AUT University, 2008.Includes bibliographical references. Also held in print ( xi, 105 leaves : ill. ; 30 cm.) in the Archive at the City Campus (T 621.382 LOL)
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SOUZA, RAMON DE ATTAYDE BARROS DE. "EVALUATION OF PRESENCE OF HEBICIDE PARAQUAT IN RUNNOF IN WATERSHED BOM JARDIM WITH MODELLING AND SIMULATION WITH SIG (GEOGRAPHICAL INFORMATION SYSTEM)." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15130@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROEsta tese propõe avaliar a presença do herbicida paraquat no escoamento superficial, ocorrido na microbacia do Córrego Pito Aceso, localizada em Bom Jardim-RJ, utilizando inicialmente uma etapa de modelagem e, posteriormente, uma etapa de simulação com SIG (Sistema de Informação Geográfica). A etapa da modelagem foi desenvolvida especificamente para cinco parcelas padrão Wischmeier, considerando suas respectivas culturas, manejo, tipo de solo e os seguintes parâmetros de influência no escoamento: interceptação do pesticida pela cultura, sorção do pesticida no solo. O fator de declividade da bacia hidrográfica foi considerado apenas para a etapa de simulação com SIG. Os resultados foram representados através de índices e concentrações de paraquat presente no escoamento e, posteriormente validados, através de dados reais medidos na área de estudo, e analisados pela EMBRAPA SOLOS. Uma vez validados, os resultados das parcelas foram georeferenciados em mapas poligonais e matriciais, através do software Arcgis 9.2, dando início, assim, a etapa de simulação dos resultados para toda a bacia hidrográfica. Pretende-se, ao final, avaliar o grau de influencia de alguns parâmetros considerados, tais como: interceptação do paraquat pela cultura e declividade da bacia hidrográfica. Os resultados das concentrações do paraquat (presente no escoamento) poderão em trabalhos futuros, serem comparados com os padrões mínimos aceitáveis para segurança ambiental, objetivando estabelecer limites de uso do paraquat em bacias hidrografias similares. Espera-se também, o desenvolvimento e aplicação da mesma modelagem utilizada nessa tese, para outros tipos de pesticidas aplicados e em diferentes bacias hidrográficas.
This study proposes to evaluate the presence of the herbicide paraquat in runoff water in a catchment in the municipality of Bom Jardim – RJ, using two steps: modelling and simulation with GIS (Geographical Information System). The step of modelling was developed specifically for five standarded Wischmeier scenarios, considering the respective crops, management, soil type and the following parameters: culture interception and soil of the sorption. The slope was considered only for the simulation steps of the GIS. The results were represented as rates paraquat concentrations in runoff and afterwards validated with real data measured in the study area and analysed by EMBRAPA SOLOS. After validation, the scenario results was georeferenced as raster images using the Arcgis Software 9.2, beginning the result simulation step for the watershed. The aim is also to evaluate the influence of some parameters: paraquat interception by the crop and slop of the catchmente. The results of paraquat concentrations in the runoff can, in the future , be compared with accepted standards for environmental safety, defining thereshobes limits of paraquat use in similar watersheds. We also expect the development and application of the same modeling approach used in this study for other types of pesticides and in different watersheds.
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Eugénio, António Luís Beja. "The information systems and technology innovation process: a study using an agent-based approach." Master's thesis, Instituto Superior de Economia e Gestão, 2007. http://hdl.handle.net/10400.5/636.
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Mestrado em Gestão de Sistemas de InformaçãoUm modelo abstracto baseado em agentes é utilizado para estudar a inovação em Sistemas de Informação e em Tecnologia de Informação, no plano organizacional, utilizando uma aproximação sócio-cognitiva. A conclusão do estudo indica que o poder dos profissionais conhecedores de tecnologias de informação na decisão de adopção de uma determinada inovação varia com o nível de concordância de ideias entre eles e os decisores, ao mesmo tempo que depende da taxa de depreciação das transacções, conduzindo a uma forte flutuação de poder quando o ambiente é instável.
An abstract Agent Based Model is used to study Information Systems and Information Technology innovation on an organizational realm, using a socio-cognitive approach. Conclusion is drawn that the power of the knowledge workers in the decision to adopt an IS/IT innovation within an organization varies with the matching level of ideas between them and the top management, while being dependant of the transactions’ depreciation rate, leading to a strong fluctuation of power when the environment is unstable.
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Frykskog, David, and Hjalmar Jonsson. "Construction of RF-link budget template for transceiver modelling." Thesis, Linköpings universitet, Fysik och elektroteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162159.
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This master thesis report details the process of developing a simulation platform for radio transceivers with a focus on analog receiver front end system design. The platform was implemented in the National Instruments VSS environment for the company Ericsson AB.
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Tabibzadeh, Sam, and Adrian Moradi. "Modellering av ett rapportgenereringssystem ur ett designperspektiv." Thesis, Uppsala universitet, Institutionen för informatik och media, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324968.
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Skrivandet av rapporter är en väldigt viktig del i många samhällssektorer. Detta genomförs för det mesta manuellt idag. Att kunna automatisera rapportgenereringen har länge varit ett mål då utvecklandet av en sådan lösning skulle spara mycket tid och resurser. Frågan om hur en infrastruktur för automatiserad rapportgenerering kan se ut är väldigt aktuell både förforskning och för organisationer. Försvarsmakten är inget undantag, idag skriver de rapporter manuellt när de använder sig av ett simuleringssystem för fiktiva strider som de senare använder sig av för träning av personal. För att undersöka hur en infrastruktur för automatiserad rapportgenerering kan se ut har vi samarbetat med Totalförsvarets forskningsinstitut (FOI). Det vi presenterar i uppsatsen är en informationsinfrastrukturmodell. Modellen är framtagen ur ett designperspektiv och behandlar en informationsinfrastruktur som är till stöd för ett simuleringssystem. Modellen är utvecklad på så sätt att den tar hänsyn till både den praktiska- och forskningsrelaterade synvinkeln. Med hjälp av krav som samlades in via intervjuer och samtal med FOI, Försvarsmakten och en expert inom området informationsinfrastruktur så tog vi de praktiska aspekterna vid utvecklandet av modellen i beaktande. De forskningsrelaterade aspekterna för utvecklandet av modellen beaktas genom tidigare studier och metoder för att ge modellen en akademisk grund.Writing reports is very important in many functions of society and is mostly done manually today. To be able to automate the generation of reports has for a long time been a challenge, and a solution would save time and resources. The question of how an infrastructure of an automated report generator could be designed is very relevant for both research and practice. The Swedish Armed Forces is no exception, currently they write reports manually when they use their simulation system for fictional battles which they later on use for training of personnel. We have cooperated with the Swedish Defence Research Agency (FOI) to study this question. In this study, we present an information infrastructure model. The model is based upon a design perspective and concerns an information infrastructure that supports a simulation system. The model takes into account both practical and research related perspectives. With the help of requirements that were gathered via interviews and discussions with FOI, Swedish Armed Forces and an expert within the field of information infrastructure, we took into account practical related aspects in the development of the model. The research related aspects are taken into account by using other studies and methods.
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Denizot, Audrey. "Simulation de la signalisation calcique dans les prolongements fins astrocytaires." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI093/document.
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Les astrocytes sont des cellules gliales du système nerveux central, essentielles à la formation des synapses, à la barrière hémato-encéphalique ainsi qu’au maintien de l'homéostasie. Récemment, les astrocytes ont été identifiés comme éléments clés du traitement de l'information dans le système nerveux central. Les astrocytes peuvent communiquer avec les neurones au niveau des synapses et moduler la communication neuronale en libérant des gliotransmetteurs et en absorbant des neurotransmetteurs. L’utilisation de nouvelles techniques comme la microscopie à super-résolution et les indicateurs calciques encodés génétiquement a permis de révéler une grande diversité spatio-temporelle des signaux calciques astrocytaires. La majorité de ces signaux sont observés au sein de leurs prolongements cellulaires, qui sont le site de communication entre neurones et astrocytes. Ces prolongements sont trop fins pour être observés en microscopie optique conventionnelle, de sorte que la microscopie à super-résolution et la modélisation informatique sont les seules méthodes adaptées à leur étude. Les travaux présentés dans cette thèse ont pour but d’étudier l'effet des propriétés spatiales (telles que la géométrie cellulaire, les distributions moléculaires et la diffusion) sur les signaux calciques dans les prolongements astrocytaires. Historiquement, les signaux calciques ont été modélisés à l'aide d'approches déterministes non spatiales. Ces modèles ont permis l'étude des signaux calciques à l’échelle de la cellule entière voire à l’échelle du réseau de cellules. Ces méthodes ne prennent cependant pas en compte la stochasticité inhérente aux interactions moléculaires ainsi que les effets de diffusion, qui jouent un rôle important dans les petits volumes. Cette thèse présente un modèle stochastique et spatial qui a été développé dans le but d’étudier les signaux calciques dans les prolongements fins astrocytaires. Ce travail a été réalisé en collaboration avec des expérimentateurs, qui nous ont fourni des données de microscopie électronique et à super-résolution. Ces données ont permis de valider le modèle. Les simulations du modèle suggèrent que (1) la diffusion moléculaire, fortement influencée par la concentration et la cinétique des buffers calciques endogènes et exogènes, (2) l'organisation spatiale intracellulaire des molécules, notamment le co-clustering des canaux calciques, (3) la géométrie du reticulum endoplasmique et sa localisation dans la cellule, (4) la géométrie cellulaire influencent fortement les signaux calciques et pourraient être responsables de leur grande diversité spatio-temporelle. Ces travaux contribuent à une meilleure compréhension du traitement de l’information par les astrocytes, un prérequis pour une meilleure compréhension de la communication entre les neurones et les astrocytes ainsi que de son influence sur le fonctionnement du cerveauAstrocytes are predominant glial cells in the central nervous system, which are essential for the formation of synapses, participate to the blood-brain barrier and maintain the metabolic, ionic and neurotransmitter homeostasis. Recently, astrocytes have emerged as key elements of information processing in the central nervous system. Astrocytes can contact neurons at synapses and modulate neuronal communication via the release of gliotransmitters and the uptake of neurotransmitters. The use of super-resolution microscopy and highly sensitive genetically encoded Ca2+ indicators (GECIs) has revealed a striking spatiotemporal diversity of Ca2+ signals in astrocytes. Most astrocytic signals occur in processes, which are the sites of neuron-astrocyte communication. Those processes are too fine to be resolved by conventional light microscopy so that super-resolution microscopy and computational modeling remain the only methodologies to study those compartments. The work presented in this thesis aims at investigating the effect of spatial properties (as e.g cellular geometry, molecular distributions and diffusion) on Ca2+ signals in those processes, which are deemed essential in such small volumes. Historically, Ca2+ signals were modeled with deterministic well-mixed approaches, which enabled the study of Ca2+ signals in astrocytic networks or whole-cell events. Those methods however ignore the stochasticity inherent to molecular interactions as well as diffusion effects, which both play important roles in small volumes. In this thesis, we present the spatially-extended stochastic model that we have developed in order to investigate Ca2+ signals in fine astrocytic processes. This work was performed in collaboration with experimentalists that performed electron as well as super-resolution microscopy. The model was validated against experimental data. Simulations of the model suggest that (1) molecular diffusion, strongly influenced by the concentration and kinetics of endogenous and exogenous buffers, (2) intracellular spatial organization of molecules, notably the co-clustering of Ca2+ channels, (3) ER geometry and localization within the cell, (4) cellular geometry strongly influence Ca2+ dynamics and can be responsible for the striking diversity of astrocytic Ca2+ signals. This work contributes to a better understanding of astrocyte Ca2+ signals, a prerequisite for understanding neuron-astrocyte communication and its influence on brain function
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Rossetti, Rosaldo Jose Fernandes. "A BDI-based approach for the assessment of driver's decision-making in commuter scenarios." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2002. http://hdl.handle.net/10183/5595.
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O rápido crescimento das regiões urbanas tem impacto significativo nos sistemas de tráfego e transportes. Políticas de gerenciamento e estratégias de planejamento alternativas são claramente necessárias para o tratamento da capacidade limitada, e cada vez mais deficitária, das redes viárias. O conceito de Sistemas Inteligentes de Transportes (ITS) surge neste cenário; mais do que procurar aumentar a capacidade por meio de modificações físicas na infraestrutura, sua premissa baseia-se na utilização de tecnologias avançadas de comunicação e computação para melhor gerir os recursos de tráfego e transportes atuais. Influenciar o padrão do comportamento dos usuários é um desafio que tem estimulado muita pesquisa na área de ITS, onde fatores humanos passam a ter grande importância na modelagem, simulação e avaliação dessa abordagem inovadora. Este trabalho tem como foco a utilização de Sistemas Multiagentes (MAS) na representação dos sistemas de tráfego e transporte, com base nas novasmedidas de desempenho impostas pelas tecnologias ITS. As características de agentes têm grande potencial para representar componentes geográfica e funcionalmente distribuídos, como a maioria dos elementos no domínio da aplicação. Uma arquitetura BDI (beliefs, desires, intentions) é apresentada como alternativa a modelos tradicionais, usados para representar o comportamento do motorista em simulação microscópica, considerando-se a representação explícita dos estados mentais dos usuários. Os conceitos básicos de ITS e MAS são apresentados, assim como exemplos de aplicações relacionados com o tema do trabalho. Esta foi a motivação para a extensão de um simulador microscópico existente, no sentido de incorporar as características dos MAS para melhorar a representação dos motoristas. Assim, a demanda é gerada a partir de uma população de agentes, resultando da decisão sobre a rota e o tempo de partida ao longo de vários dias. O modelo estendido, que passa a suportar a interação de motoristas BDI, foi efetivamente implementado e foram executados diferentes experimentos para testar a abordagem em cenários de tráfego urbano. MAS permite uma abordagem direcionada a processos que facilita a construção de representações modulares, robustas, e extensíveis, características pouco presentes em abordagens voltadas ao resultado. Suas premissas de abstração permitem uma associação direta entre modelo e implementação. Incerteza e variabilidade são assim tratadas de maneira mais intuitiva, uma vez que arquiteturas cognitivas permitem uma fácil representação do comportamento humano na estrutura do motorista. Desta forma, MAS estende a simulação microscópica de tráfego no sentido de melhor representar a complexidade inerente às tecnologias ITS.The rapid growth of urban areas has a significant impact on traffic and transportation systems. New management policies and planning strategies are clearly necessary to cope with the more than ever limited capacity of existing road networks. The concept of Intelligent Transportation System (ITS) arises in this scenario; rather than attempting to increase road capacity by means of physical modifications to the infrastructure, the premise of ITS relies on the use of advanced communication and computer technologies to handle today’s traffic and transportation facilities. Influencing users’ behaviour patterns is a challenge that has stimulated much research in the ITS field, where human factors start gaining great importance to modelling, simulating, and assessing such an innovative approach. This work is aimed at using Multi-agent Systems (MAS) to represent the traffic and transportation systems in the light of the new performance measures brought about by ITS technologies. Agent features have good potentialities to represent those components of a system that are geographically and functionally distributed, such as most components in traffic and transportation. A BDI (beliefs, desires, and intentions) architecture is presented as an alternative to traditional models used to represent the driver behaviour within microscopic simulation allowing for an explicit representation of users’ mental states. Basic concepts of ITS and MAS are presented, as well as some application examples related to the subject. This has motivated the extension of an existing microscopic simulation framework to incorporate MAS features to enhance the representation of drivers. This way demand is generated from a population of agents as the result of their decisions on route and departure time, on a daily basis. The extended simulation model that now supports the interaction of BDI driver agents was effectively implemented, and different experiments were performed to test this approach in commuter scenarios. MAS provides a process-driven approach that fosters the easy construction of modular, robust, and scalable models, characteristics that lack in former result-driven approaches. Its abstraction premises allow for a closer association between the model and its practical implementation. Uncertainty and variability are addressed in a straightforward manner, as an easier representation of humanlike behaviours within the driver structure is provided by cognitive architectures, such as the BDI approach used in this work. This way MAS extends microscopic simulation of traffic to better address the complexity inherent in ITS technologies.
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Abideen, Amar. "Dielectric Response and Partial Discharge Characteristics of Stator Winding Insulation System with SiC Stress Grading." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284502.
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The typical construction of a stator coil includes the use of end corona protection (ECP)coating, which is made of semi-conductive materials like silicon carbide (SiC). Thepurpose of ECP is to smooth the electric stress distribution near the slot exit, limitingthe electric field and partial discharge (PD) activity within the insulation system. Thisthesis investigates how ECP affects the dielectric response of a stator coil in highvoltagemeasurements, both in the time-domain and frequency-domain. It also studieshow well time-domain results transformed to the frequency-domain correspond to directmeasurements. As a further point, the effect of the ECP on PD activity was demonstrated.Measurements of dielectric response and PD were made on new coil-halves producedin the usual way in a production run for a motor. The results show that applying theECP design significantly reduces the PD activity and increases the inception voltage. Inaddition, the dielectric response of the coil with ECP tape has shown to have a nonlinearvoltage dependent characteristic due to the presence of ECP. As the voltage goes higher,this causes a shift of the loss peak toward higher frequency. A distributed-element modelof the end section of a stator coil was used to model the nonlinear effect due to ECP, andits results are compared to the measured results. Lastly, FEM simulation of a stator coilend section is presented, showing the contribution of ECP tape in evenly distributing theelectric stress near the slot exit.Den typiska konstruktionen av en statorhärva använder ändglimmskydd (ECP), somär tillverkad av halvledande material som kiselkarbid (SiC). Syftet med ECP är attjämna ut det elektriska fältet vidövergången från spåret tilländlindningen, för attundvika högpåkänning och partiell urladdningsaktivitet (PD). Arbetet som presenteras här undersöker hur ECP påverkar den dielektriska responsen hos en statorspole, vid tidsdomänoch frekvensdomänmätningar vid höga spänningar. Den studerar också hur väl tidsdomänresultat som omvandlas till frekvensdomänen motsvarar direkta mätningar. Som en annan punkt visades ECP:s inverkan på PD-aktivitet. Mätningar av dielektrisk respons och PD gjordes på nya statorhärvor som tillverkades för en stor motor. Resultaten visar att tillämpningen av ECP-konstruktionen avsevärt minskar PD-aktiviteten och ökar inceptionsspänningen. Dessutom har spolens dielektriska respons med ECP-tejp visat sig ha en ickelinjär spänningsberoende egenskap på grund av närvaron av ECP. Ö kad spänning orsakar en förskjutning av förlusttoppen mot högre frekvens. En modell för ECP användeseteendet, och dess resultat jämförs med mätningarna.utligen presenteras FEM-simulering som visar hur ECP gör fältet jämnare.
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Kunštátský, Martin. "Sebeorganizace v rozsáhlých distribuovaných systémech." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2012. http://www.nusl.cz/ntk/nusl-236530.
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Gossip is a generic protocol which was designed for spreading information between nodes in large distributed decentralised systems. This protocol can be also used for many different applications including data aggregation, topology construction, etc. This work presents and describes a framework designed for facilitating modelling and simulation of Gossip-based systems.
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Johansson, Jenny, and Mikaela Waller. "Control Oriented Modeling of the Dynamics in a Catalytic Converter." Thesis, Linköping University, Department of Electrical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-4154.
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Avgasmängden som bensindrivna fordon tillåts släppa ut minskas hela tiden. Ett sätt att möta framtida krav, är att förbättra katalysatorns effektivitet. För att göra detta kan luft-bränsle-förhållandet regleras med avseende på syrelagringen i katalysatorn, istället för som idag, reglera mot stökiometriskt blandningsförhållande. Eftersom syrelagringen inte går att mäta med en givare behövs en modell som beskriver katalysatorns dynamiska egenskaper. Tre sådana modeller har undersökts, utvärderats och jämförts.
Två av modellerna har implementerats i Matlab/Simulink och anpassats till mätningar från en experimentuppställning. För att kunna observera syrelagringen online valdes slutligen en av modellerna ut, och implementerades i ett Extended Kalman filter.
Ytterligare arbete behöver läggas ner på den mest lovande modellen, och detsamma gäller för Kalmanfiltret, men på sikt förväntas resultaten kunna bli bra.
The legal amount of emissions that vehicles with spark ignited engines are allowed to produce are steadily reduced over time. To meet future emission requirements it is desirable to make the catalytic converter work in a more efficient way. One way to do this is to control the air-fuel-ratio according to the oxygen storage level in the converter, instead of, as is done today, always trying to keep it close to stoichiometric. The oxygen storage level cannot be measured by a sensor. Hence, a model describing the dynamic behaviors of the converter is needed to observe this level. Three such models have been examined, validated, and compared.
Two of these models have been implemented in Matlab/Simulink and adapted to measurements from an experimental setup. Finally, one of the models was chosen to be incorporated in an extended Kalman filter (EKF), in order to make it possible to observe the oxygen storage level online.
The model that shows best potential needs further work, and the EKF is working with flaws, but overall the results are promising.
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Oezkan, Oezguer. "Operational modelling practical manufacturing systems." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323768.
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Petrounias, Ilias. "Conceptual modelling for temporal information systems." Thesis, University of Manchester, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488408.
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Cordeiro, José A. M. "Normative approach to information systems modelling." Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553135.
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Information and communication technologies (ICT) and computer systems m general are increasingly integrating daily life and- becoming an essential element of human and organisational existence in modem societies. The Information Systems (IS) field in particular is interested in enhancing processes and increasing the utility of information to organisations and their members by using these technologies. However, most IS development methodologies are technologically biased by employing engineering approaches originated in software engineering and related fields to the analysis, design and implementation of those systems forgetting human and organisational nature of information and IS. These methodologies fail to: (i) acknowledge properly the role of humans and its associated social, cultural, political and behavioural dimensions (ii) understand the real interplay between human and technology and (iii) provide a sound and appropriate philosophical foundation. This thesis is mainly built upon the work and findings from three different but related theories that take the human as a central element of any IS, namely Organisational Semiotics (OS), the Theory of Organized Activity (TOA) and Enterprise Ontology (EO), and broader and related theories of respectively, Semiotics, Activity Theory and Language Action Perspective. In this research a deep analysis is undertaken regarding these theories to explore and compare their fundamental aspects and to derive their essential elements. This research proposes a new intellectual framework originated in a new philosophical foundation - Human Relativism - that adopts the human as the central element and provides a new paradigm as a basis for any methodology for IS development. A new approach - NOMIS (NOrmative Modelling of Information Systems) - is introduced, applying the new paradigm, centred in human behaviour and human action in particular, that integrates the theoretical views of OS, TOA and EO. For modelling and representation purposes a new modelling notation and an UML profile extension of the Unified Modelling Language (UML) was created for expressing and communicate the fundamental views of NOMIS. Finally, two case studies were used to 1) demonstrate the " feasibility and applicability of NOMIS for modelling a business domain and, 2) show the key concepts of NOMIS applied to the design of a computer application. Conclusions and future work completes this thesis.
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Albertyn, Martin. "Generic simulation modelling of stochastic continuous systems." Thesis, Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-05242005-112442.
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Kraus, Vladimír. "Modelling and Simulation of Pull Production Systems." Master's thesis, Vysoká škola ekonomická v Praze, 2006. http://www.nusl.cz/ntk/nusl-8579.
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Práce se zabývá modelováním a simulací výrobních systémů řízených principem tahu (kanban, CONWIP). Analyzuje vzájemný vztah průtoku, operačních zásob a doby výroby. Zohledňuje stochastické vlivy a variabilitu procesů. Teoretické základy jsou aplikovány na příkladu výrobní linky CP1H ve společnosti Bosch Diesel.
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Chi, Sungdo. "Modelling and simulation for high-autonomy systems." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185650.
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The basic objective of this research is to develop an architecture for systems capable of highly autonomous behavior by combining decision (intelligence), perception (sensory processing), and action (effector) components. The major challenge of this dissertation is the integration of high-level symbolic models with low-level dynamic (control-theoretic) models into a coherent model base. The systematic inclusion of dynamic and symbolic models each dedicated to support a single function such as planning, operations, diagnosis or perception allows us to extend existing multi-layered control and information architectures. A knowledge-based simulation environment is employed to simulate and verify the proposed integrated model-based architecture. The constructed working simulation version of an autonomous robot-managed laboratory demonstrates the use of multiple model families for experiment planning and execution. Tools to support the development and integration of such model families are also developed. The developed model-based architecture is elaborated by incorporating time-based simulation and causal propagation model families supporting diagnosis, repair, and replanning. This involves tools to automatically extract such models from more detailed dynamic models and structural knowledge. Systems with high levels of autonomy are critical for unmanned, and partially manned, space missions. The utility of the proposed high autonomy system will be demonstrated with models of a robot-managed fluid handling laboratory for International Space Station Freedom to be used for research in life sciences, microgravity sciences, and space medicine. NASA engineers will be able to base designs of intelligent controllers for such systems on the architecture developed in this dissertation. They will be able to employ our tools and simulation environment to verify such designs prior to their implementation.
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Mizeranschi, Alexandru E. "Multiscale modelling and simulation in systems biology." Thesis, Ulster University, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.737992.
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The focus of this thesis was determined by the FP7-funded e-infrastructure project Multiscale Applications on European e-Infrastructures (MAPPER). The main goal of MAPPER was to develop a distributed multiscale computing framework facilitating the development, deployment and use of multiscale modelling and simulation applications in various domains. MAPPER was strongly involved with the computing aspects of multiscale modelling and simulation. Within the MAPPER project, the research described in this thesis was focused on the development of novel (a) general multiscale modelling and simulation methods and technologies, and (b) multiscale computational systems biology methods and tools. We chose gene regulation as the main biological problem domain to drive our R&D efforts. An important way to investigate gene regulation is through automated reverse engineering of mechanistic dynamic GRN models from gene expression time- series data. This, however, is limited by the quality and amount of available data and the computational complexity of the reverse-engineering process. The specific objective of this thesis was to develop and assess novel solutions for reverse-engineering GRN models from gene expression data. This objective was explored from three main perspectives. First, to facilitate the development of improved approaches to GRN model reverse-engineering, we explored the representational and computational aspects of various GRN rate laws. Second, we explored how the computational aspects of the GRN model reverse-engineering problem could be viewed as a distributed multiscale computing problem. A major piece of R&D that resulted from this was the development of MultiGrain/MAPPER, a software tool that allows the multiscale modelling and simulation of GRNs. Third, based on MultiGrain/MAPPER and other software we created, we developed and assessed various new reverse-engineering algorithms and investigated their performance in terms of effectiveness and efficiency.
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Tomlinson, S. P. "The hydraulic automatic simulation package (HASP) : Modelling and simulation aspects." Thesis, University of Bath, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375337.
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Tsalgatidou, Aphrodite. "Dynamics of information systems : modelling and verification." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257152.
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Cutts, Geoff. "Modelling and analysis of parallel information systems." Thesis, Sheffield Hallam University, 1993. http://shura.shu.ac.uk/19524/.
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This thesis presents an investigation of modelling and analysis of parallel information systems. The research was motivated by the recent developments in networks and powerful, low-cost, desk top multiprocessors. An integrated approach for the construction of parallel information systems was developed which focussed on modelling, verification and simulation of such systems. The thesis demonstrates how Petri nets can be used for the modelling and analysis of entity life histories and parallel information systems, place transition nets for the modelling and analysis of entity life histories and coloured Petri nets for the modelling and analysis of complex parallel information systems. These tools were integrated into a comprehensive framework which allowed for the modelling and analysis of complex parallel information systems and the framework was tested using a comprehensive case study. The thesis concludes that Petri nets are an ideal tool for the modelling and analysis of complex parallel systems. Verification is possible with deadlocks and similar properties being easily identified. Further the transformation rules proved to be beneficial to the process of moving from one model to another. Finally simulation of parallel behaviour was possible because the underlying models captured the notion of parallelism.
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Solgård, Stian Bu. "Modelling, simulation and control of macro economic systems." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9023.
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Today's Basel-type banking system is compared with a 100% reserve banking system. Furthermore, negative interest rate on deposits is introduced for these two systems thus two new models are introduced. Eventually all four models are compared with each other in terms of debt crisis mechanisms and if they are prone to enter a liquidity trap. The comparing is done for debt to GDP ratio around a certain ratio of 60% thought to give neutral confidence, thus the effect from confidence dynamics can be excluded for these simulations.
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Shoaki, Salman Daif-Allah. "Generic robotic manufacturing systems : modelling/simulation and control." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390617.
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Gow, John A. "Modelling, simulation and control of photovoltaic converter systems." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6871.
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The thesis follows the development of an advanced solar photovoltaic power conversion system from first principles. It is divided into five parts. The first section shows the development of a circuit-based simulation model of a photovoltaic (PV) cell within the 'SABER' simulator environment. Although simulation models for photovoltaic cells are available these are usually application specific, mathematically intensive and not suited to the development of power electronics. The model derived within the thesis is a circuit-based model that makes use of a series of current/voltage data sets taken from an actual cell in order to define the relationships between the cell double-exponential model parameters and the environmental parameters of temperature and irradiance. Resulting expressions define a 'black box' model, and the power electronics designer may simply specify values of temperature and irradiance to the model, and the simulated electrical connections to the cell provide the appropriate I/V characteristic. The second section deals with the development of a simulation model of an advanced PVaware DC-DC converter system. This differs from the conventional in that by using an embedded maximum power tracking system within a conventional linear feedback control arrangement it addresses the problem of loads which may not require the level of power available at the maximum power point, but is also able to drive loads which consistently require a maximum power feed such as a grid-coupled inverter. The third section details a low-power implementation of the above system in hardware. This shows the viability of the new, fast embedded maximum power tracking system and also the advantages of the system in terms of speed and response time over conventional systems. The fourth section builds upon the simulation model developed in the second section by adding an inverter allowing AC loads (including a utility) to be driven. The complete system is simulated and a set of results obtained showing that the system is a usable one. The final section describes the construction and analysis of a complete system in hardware (c. 500W) and identifies the suitability of the system to appropriate applications.
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Lavery, Eamonn. "Object oriented modelling and simulation of manufacturing systems." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361254.
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Hayat, Tariq. "Modelling, simulation and control of mine ventilation systems." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387494.
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Saghafi, Arash. "Ontological and cognitive principles on information systems modelling." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59427.
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Information systems are representations or models of real-world applications. Based on this premise, success of an information system is contingent on how effectively and faithfully the representations are generated and interpreted by analysts and designers. Prior research has suggested using ontology — a branch of philosophy that deals with the order and structure of reality in the broadest sense — as guidance for the modelling process. It is expected that by improving the ontological expressiveness of conceptual models, they will become more faithful and effective representations of the real world. This thesis focuses on information models that are rooted in ontology and users’ performance of cognitive tasks when using such models. Following the three-study structure of doctoral theses, my first study synthesized the prior work that had empirically evaluated the impact of ontological guidance on users’ understanding of conceptual models. The analysis indicated a strong effect of ontological guidance on improving users’ understanding of the “conceptual domain models”, particularly for tasks that required a deeper level of understanding. This provides scientific evidence in favour of incorporating ontological guidance in education and in practice of systems analysis. My second and third studies investigated a data modelling approach that is based on ontological principles, namely the instance-based paradigm, which is an alternative to the traditional data management method. Unlike the traditional approach, the instance-based paradigm requires neither imposing pre-defined structure over the data nor central control/planning. Study 2 evaluated users’ performance in (the cognitive task of) information retrieval. It indicated that users of instance-based representations are able to formulate queries more accurately compared with users of class-based representations. Study 3 broadened the scope and focused on knowledge discovery and exploration of information (that was not necessarily created for the intended application). Results of a laboratory experiment demonstrated that users of instance-based data were able to identify more potentially interesting patterns compared with users of class-based data. With the current emphasis on information analytics and importance of incorporating insights from organizational data into decision-making, the latter two studies show that the instance-based model is a promising approach to satisfy the emerging needs of information users.Business, Sauder School of
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Fragos, Serafeim. "Behavioural modelling in management and accounting information systems." Thesis, Lancaster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.483621.
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Saad, Nordin. "Modelling, simulation, and analysis of supply chain systems using discrete-event simulation." Thesis, University of Sheffield, 2003. http://etheses.whiterose.ac.uk/14771/.
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Many approaches have been developed which support the construction of detailed supply chain models useful for analysis and simulation. However, most of these approaches lack the ability to model the supply chain in a single model, and usually produce solutions that lead to conflicting strategies between the companies. Simulation using a discrete-event simulation (DES) is an effective tool for the dynamically changing supply chain variables, thus allowing the system to be modelled more realistically. Considering the complexities of the supply chain system and the interrelations between its various systems, the task of developing such a model is challenging. The aim of this thesis is to develop a simulation model of a fast moving consumer goods (FMCG) supply chain with a DES tool. This model would be utilised as a decision-support system (DSS) for the investigation of the effectiveness of several inventory policies towards effective coordination and control of production inventory system, in various situations. This thesis discusses fundamental issues in the development of a simulation model for a supply chain using the DES tool, ARENA. A modelling procedure for the development of a supply chain simulation model is presented. The overall structure of the model is constructed by incorporating the well documented concept of modelling materials flowing downstream with an approach of modelling orders flowing upstream (modelling of feedback information). The model has an easily adaptable structure where rules (inventory policies) and model variables can be modified. The flexibility in the model's structure allows devising appropriate experimental designs, for several tests to be performed to imitate some realistic situations or scenarios (including the presence of disturbances). A new control theory oriented inventory policy, called the pseudo PID, is proposed. Detailed evaluations of five inventory policies for a production-inventory control under dynamic and stochastic conditions is presented. The findings demonstrate the ability of the approach to provide a wealth of potential solutions to the decision-maker, and confirm the qualitative behaviour of a supply chain in response to the different policies.
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Geitner, Gert-Helge, and Guven Komurgoz. "Power Flow Modelling of Dynamic Systems." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-171305.
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As tools for dynamic system modelling both conventional methods such as transfer function or state space representation and modern power flow based methods are available. The latter methods do not depend on energy domain, are able to preserve physical system structures, visualize power conversion or coupling or split, identify power losses or storage, run on conventional software and emphasize the relevance of energy as basic principle of known physical domains. Nevertheless common control structures as well as analysis and design tools may still be applied. Furthermore the generalization of power flow methods as pseudo-power flow provides with a universal tool for any dynamic modelling. The phenomenon of power flow constitutes an up to date education methodology. Thus the paper summarizes fundamentals of selected power flow oriented modelling methods, presents a Bond Graph block library for teaching power oriented modelling as compact menu-driven freeware, introduces selected examples and discusses special features.
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Ahmadi, Achachlouei Mohammad. "Exploring the Effects of ICT on Environmental Sustainability: From Life Cycle Assessment to Complex Systems Modeling." Doctoral thesis, KTH, Miljöstrategisk analys (fms), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171443.
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The production and consumption of information and communication technology (ICT) products and services continue to grow worldwide. This trend is accompanied by a corresponding increase in electricity use by ICT, as well as direct environmental impacts of the technology. Yet a more complicated picture of ICT’s effects is emerging. Positive indirect effects on environmental sustainability can be seen in substitution and optimization (enabling effects), and negative indirect effects can be seen in additional demand due to efficiency improvements (rebound effects). A variety of methods can be employed to model and assess these direct and indirect effects of ICT on environmental sustainability. This doctoral thesis explores methods of modeling and assessing environmental effects of ICT, including electronic media. In a series of five studies, three methods were at times applied in case studies and at others analyzed theoretically. These methods include life cycle assessment (LCA) and complex systems modeling approaches, including System Dynamics (SD) and agent-based (AB) modeling. The first two studies employ the LCA approach in a case study of an ICT application, namely, the tablet edition of a Swedish design magazine. The use of tablets has skyrocketed in recent years, and this phenomenon has been little studied to date. Potential environmental impacts of the magazine’s tablet edition were assessed and compared with those of the print edition. The tablet edition’s emerging version (which is marked by a low number of readers and low reading time per copy) resulted in higher potential environmental impacts per reader than did the print edition. However, the mature tablet edition (with a higher number of readers and greater reading time per copy) yielded lower impacts per reader in half the ten impact categories assessed. While previous studies of electronic media have reported that the main life-cycle contributor to environmental impacts is the use phase (which includes operational electricity use as well as the manufacture of the electronic device), the present study did not support those findings in all scenarios studied in this thesis. Rather, this study found that the number of readers played an important role in determining which life-cycle phase had the greatest impacts. For the emerging version, with few readers, content production was the leading driver of environmental impacts. For the mature version, with a higher number of readers, electronic storage and distribution were the major contributors to environmental impacts. Only when there were many readers but low overall use of the tablet device was the use phase the main contributor to environmental impacts of the tablet edition of the magazine. The third study goes beyond direct effects at product- and service-level LCAs, revisiting an SD simulation study originally conducted in 2002 to model indirect environmental effects of ICT in 15 European countries for the period 2000-2020. In the current study, three scenarios of the 2002 study were validated in light of new empirical data from the period 2000–2012. A new scenario was developed to revisit the quantitative and qualitative results of the original study. The results showed, inter alia, that ICT has a stimulating influence on total passenger transport, for it makes it more cost- and time-efficient (rebound effects). The modeling mechanism used to represent this rebound effect is further investigated in the fourth study, which discusses the feedback loops used to model two types of rebound effects in passenger transport (direct economic rebound and time rebound). Finally, the role of systems thinking and modeling in conceptualizing and communicating the dynamics of rebound effects is examined. The aim of the fifth study was to explore the power of systems modeling and simulation to represent nonlinearities of the complex and dynamic systems examined elsewhere in this thesis. That study reviews previous studies that have compared the SD and AB approaches and models, summarizing their purpose, methodology, and results, based on certain criteria for choosing between SD and AB approaches. The transformation procedure used to develop an AB model for purposes of comparison with an SD model is also explored. In conclusion, first-order or direct environmental effects of ICT production, use, and disposal can be assessed employing an LCA method. This method can also be used to assess second-order or enabling effects by comparing ICT applications with conventional alternatives. However, the assessment of enabling effects can benefit from systems modeling methods, which are able to formally describe the drivers of change, as well as the dynamics of complex social, technical, and environmental systems associated with ICT applications. Such systems methods can also be used to model third-order or rebound effects of efficiency improvements by ICT.Den ökande produktionen och konsumtionen av produkter och tjänster inom informations- och kommunikationsteknik (IKT) leder till en ökning av den globala elanvändningen samt direkta miljökonsekvenser kopplade till IKT. Men IKT har även indirekta miljömässiga effekter. Dessa kan vara positiva till exempel genom substitutions- och optimeringseffekter eller negativa genom att till exempel ge upphov till ytterligare efterfrågan på grund av effektivisering (så kallade reboundeffekter). Olika metoder kan användas för att modellera och bedöma både direkta och indirekta effekter av IKT. Syftet med denna avhandling är att undersöka metoder för modellering samt att studera miljöeffekter av IKT och elektronisk media med hjälp av livscykelanalys (LCA) och även modellering av komplexa och dynamiska system, samt simuleringsteknik, så som System Dynamics (SD) och agentbaserad (AB) modellering. Avhandlingen omfattar fem artiklar (artikel I-V). Artikel I & II beskriver resultaten från en fallstudie där miljöeffekter kopplade till en svensk tidskrift studeras med LCA. Tidskriftens version för surfplatta samt motsvarande tryckta version studeras och jämförs. Artikel III går ett steg vidare från produktnivåns LCA. Artikeln återkopplar till en SD simuleringsstudie som ursprungligen genomfördes under 2002. Simuleringsstudien gällde framtida miljöeffekter av IKT i 15 europeiska länder med tidspespektivet 2000-2020. I artikeln valideras tre scenarier från simuleringsstudien med hjälp av nya empiriska data från 2000-2012 och ett nytt scenario modelleras. Kvantitativa och kvalitativa resultat från den ursprungliga studien diskuteras. Till exempel visar artikel III att IKT har en stimulerande effekt på den totala persontrafiken genom att göra den mer kostnads- och tidseffektiv (reboundeffekt). Modelleringsmekanismen som används för att representera denna reboundeffekt diskuteras vidare i artikel IV. Artikeln belyser och diskuterar den återkopplingsslinga (feedback-loop) som används för att modellera två typer av reboundeffekter kopplade till persontrafik (direkt ekonomisk rebound och tidsrelaterad rebound) samt jämför med en tidigare studie. Artikel IV behandlar också den roll systemtänkande och modellering kan spela i konceptualisering och kommunikation av reboundeffekters dynamik. För att ytterligare undersöka systemmodelleringens och simuleringens möjligheter att representera icke-linjära komplexa och dynamiska system (exempel på sådana diskuteras i artikel III och IV), sammanställer artikel V tidigare studier som jämför SD och AB-metoder och -modeller. Studiernas mål och metod summeras och resultaten med avseende på vilka kriterier som presenteras för att välja mellan SD och AB sammanställs. Även processen för att omvandla en befintlig SD-modell till en AB-modell beskrivs. Avhandlingens slutsats är att LCA och systemmodelleringsmetoder kan vara användbara för att studera IKTs direkta effekter så väl som indirekta effekter på miljön.
QC 20150813
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Posse, Ernesto. "Modelling and simulation of dynamic-structure discrete-event systems." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22006.
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Discrete-event modelling and simulation has become an established approach to the description and study of complex dynamic systems. In recent years there has been an increased interest in modelling complex dynamic-structure systems, i.e., systems whose structure changes over time. Such systems are generally more difficult to understand and analyze than systems with a static structure. These challenges can be met by the development of appropriate modelling formalisms based on a solid foundation and with suitable supporting tools. In this thesis we explore an approach to modelling and simulation of dynamic-structure discrete-event systems based on process algebra. The thesis consists of two parts. We begin by exploring, in the first part, a formalism for static-structure discrete-event modelling and simulation called the Discrete-EVent System Specification formalism (DEVS [Zeigler 76, 2000].) We develop an alternative theoretical foundation for DEVS based on Structural Operational Semantics, focusing on determinism and compositionality properties. In the second part we develop a modelling language for dynamic-structure discrete-event systems named kiltera, based on process algebras and incorporating elements from discrete-event modelling. This language, based on the \pi-calculus [Milner 89], allows us to describe and reason about timed, mobile and distributed discrete-event systems in a single framework. We develop a theoretical foundation based on Structural Operational Semantics and establish fundamental properties concerning time-determinism, continuity, compositionality and legitimacy. We build a simulator for the language which supports both sequential and distributed execution of models, based on a variant of the Time Warp algorithm [Jefferson 85]. Finally we apply this language to the modelling and simulation of traffic.La modélisation et la simulation à événements discrets constituent une approche bien établie pour la description et l'étude des systèmes dynamiques complexes. Ces dernières années, il y a eu un regain d'intérêt pour la modélisation des systèmes complexes à structure dynamique. Ces systèmes sont généralement plus difficiles à comprendre et à analyser que les systèmes ayant une structure statique. Cette analyse et cette compréhension peuvent être développées à l'aide de formalismes de modélisation fondés sur une base solide et des outils appropriés. Dans cette thèse, nous explorons une approche de modélisation et de simulation des systèmes à événements discrets fondée sur l'algèbre de processus. Ce document se compose de deux parties. Dans la première partie, nous étudions ce que l'on appelle le formalisme Discrete-EVent System Specifications (DEVS.) Nous développons un autre fondement théorique pour DEVS fondée sur la sémantique opérationnelle structurelle, en mettant l'accent sur les propriétés de déterminisme et de compositionalité. Dans la deuxième partie, nous développons un langage de modélisation pour systèmes à structure dynamique nommé kiltera, en nous fondant sur les algèbres de processus et en incorporant des éléments de modélisation à événements discrets. Ce langage, en se fondant sur le \pi-calcul, nous permet de décrire et de raisonner sur les systèmes mobiles, distribués et au temps-réel, à événements discrets, dans un cadre conceptuel unique. Nous développons une base théorique fondée sur la sémantique opérationnelle structurelle et nous établissons des propriétés fondamentales concernant le déterminisme-temps, la continuité, la compositionalité et la légitimité. Nous construisons un simulateur pour le langage qui supporte à la fois l'exécution séquentielle et distribuée de modèles, en utilisant une variante de l'algorithme Time Warp. Enfin, nous appliquons ce la
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Sheikholeslami, Majid. "Modelling and simulation environment for force-feedback multibody systems." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103737.
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In this work we describe a simulation environment that is developed for force feedback devices. This environment relies on the Canadian Space Agency's Multibody Toolbox (MuT) that has symbolic manipulation capabilities based on Maple and uses the Matlab/Simulink interface for numerical processing. The said simulation environment serves two purposes: (1) modelling, dynamic analysis and visualization of multibody systems to assist the design of force feedback devices; (2) generation of models of dynamic systems that serve as virtual environments with which a physical force feedback device interacts. The second item also involves the integration with Quanser's QuaRC real-time control package to control the force feedback device. This work particularly deals with the class of devices that employs the impedance control paradigm. Force feedback devices and the related virtual environment models often employ mechanical system topologies that can be represented by closed-loop multibody chains. For both of the above main objectives, the consideration of explicitly given kinematic constraints in the dynamics and control of the underlying multibody system models is of paramount importance. The simulation framework is capable of employing efficient stabilization techniques to provide satisfactory performance and is able to handle non-conservative systems which gain energy during the simulation, as if the control algorithm injects energy into the system. The simulation of constrained systems received significant attention in recent years. However, the issues that can arise from a broader interpretation of the constrained motion problem have not really been considered. Such an interpretation includes the case of linking a simulated dynamic system to a physical device, which problem has a hardware-in-the-loop nature. This is the case of haptic rendering based on force feedback mechanisms. These aspects will be illustrated via simulations and an experimental test-bed.Nous d'ecrivons ici un environnement de simulation développé pour les dispositifs de retour d'effort. Cet environnement est basé sur le Multibody Toolbox (MuT) mis au point par l'Agence spatiale canadienne, qui a la capacité de manipulation symbolique en utilisant Maple et Matlab/Simulink afin de traiter de l'interface numérique. L'environnement de simulation sert un double objets: (1) la modélisation, l'analyse dynamique et la visualisation de systèmes multicorps pour aider à la conception des dispositifs de retour d'effort, (2) la génération de modèles de systèmes dynamiques afin de servir des environnements virtuels avec lesquels un appareil physique de retour d'effort tente d'avoir interaction. Le deuxième objectif implique également l'intégration du logiciel en question avec celui pour la commande en temps réel Quanser QuaRC afin de contrôler le dispositif de retour d'effort. Ce travail porte en particulier sur la classe de dispositifs qui emploient le paradigme de commande par impédance. Les dispositifs de retour d'effort et les modèles d'environnement virtuel emploient souvent des topologies des systèmes mécaniques qui peuvent être représentées par chaînes d'éléments multicorps couplés en boucle fermée. Pour tous les deux principaux objectifs ci-dessus, l'examen des contraintes cinématiques explicitement données dans la dynamique et le contrôle des modèles sous-jacents des systèmes multicorps a une importance primordiale. Le cadre de simulation est capable d'utiliser des techniques efficaces de stabilisation afin de fournir la performance ciblée tout en étant également capable de gérer des systèmes non-conservateurs qui gagnent de l'énergie au cours de la simulation, comme si l'algorithme de contrôle injectait de l'énergie dans le système. La simulation des systèmes contraints a reçu une attention considérable durant les dernières années. Cependant, les problèmes issus d'une interprétation plus large de problème de mouvement constraint ne sont pas vraiment pris en considération. Une telle interprétation représente par la connection d'un logiciel de simulation dynamique à un dispositif faisant partie du matériel. C'est le cas de dévirage haptique basé sur des mécanismes de retour d'effort. Ces aspects seront illustrés par des simulations et un banc d'essai expérimental.
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MacQueen, John. "The modelling and simulation of energy management control systems." Thesis, University of Strathclyde, 1997. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21355.
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This thesis is concerned with improving the integrity and applicability of building energy management systems(BEMS) simulation tools. The present work attempts to overcome certain inadequacies of contemporary simulation applications with respect to environmental control systems, by developing novel building control systems modelling schemes. These schemes are then integrated within a state-of-the-art simulation environment so that they can be employed in practice. After reviewing the existing techniques and various approaches to control systems design and appraisal,a taxonomy of building control system entities grouped in terms of logical, temporal and spatial element, is presented. This taxonomy is subsequently used to identify the models, algorithms, and features comprising a comprehensive modelling environment. Schemes for improving system integrity and applicability are presented based upon a simulation approach which treats the building fabric and associated plant sy stems as an integrated dynamic system. These schemes facilitate the modelling of advanced BEMS control structure and strategies, including: - hierarchical (systems level and zone-level) control systems; - single input, single output (SISO) and multiple input, multiple output (MIMO) systems; - advanced BEMS controller algorithms; - simulated-assisted control strategies based on advanced simulation time-step control techniques. The installation of the developed schemes within a whole building simulation environment, ESP-r, is also presented. Issues related to verification of the developed schemes are subsequently discussed. Users of control system simulation programs are identified and categorised. Typical applications of the new control modelling features are demonstrated in terms of these user groups. The applications are based on both research and consultancy projects. Finally, the future work required to increase the applicability and accuracy of building control simulation tools is elaborated in terms of the required integration with other technical subsystems and related computer-aided design tools.
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Gely, Laurent. "Modélisation et optimisation de la gestion opérationnelle du trafic ferroviaire en cas d’aléas." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14177.
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La régulation ferroviaire sur de vastes zones est un problème complexe. Elle intervient dans la phase opérationnelle de la production. Son rôle consiste à trouver de nouvelles solutions en termes de planification des mouvements de trains suite à l'apparition d'un incident empêchant la réalisation normale du plan de transport préétabli dans les phases amont de la production.La contribution de ce travail s'organise autour de trois axes.Le premier consiste à définir une formalisation exhaustive du système ferroviaire, associé à une représentation plus cohérente (modèle multiniveau).Le deuxième axe s'articule autour de l'étude des modèles mathématiques pour la régulation du trafic ferroviaire: évolutions d'un modèle en temps continu complet (espacements dynamiques), proposition d'un modèle innovant à temps discret et d'un modèle mixte (continu-discret) adossé au modèle multiniveau.Enfin, le dernier axe traite de la mise en oeuvre concrète au niveau industriel, en particulier des gains attendus du couplage avec un outil de simulationOn-line re-scheduling of trains aims to find accurate solutions after an incident has occurred on the railway network. When we consider a large area, solutions consist in calculating new timetables, sequences and routes of trains. This problem asks for decision support tools based on operational research techniques.This thesis aims to develop solutions toward an operational tool, it articulates around three main parts. The first part defines an exhaustive model of the railway system operations and a multiscalable description of the infrastructure.The second part presents three mathematical models of the rescheduling problem associated with this description. We preset a exhaustive continuous time based model including headways that take into account speeds of trains, plus a discrete time based model and an hybrid model combining both formulations.The last part describes first implementations and the global framework we need to develop in order to solve the real world problem. It emphases on expected synergies, specilaly between simulation and optimization techniques
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Balaji, Kamalakkannan Balaji. "Modelling and Simulation of Vehicle Kinematics and Dynamics." Thesis, Högskolan i Halmstad, Halmstad Embedded and Intelligent Systems Research (EIS), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-34363.
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With the rapid growth in the automotive industry, vehicles have become more complex and sophisticated. Vehicle development today, involves integration of both electrical and mechanical systems. Their design and production are typically time and cost critical. To complement and support the process of vehicle development and design, majority of the automotive industry use modelling and simulationfor testing automotive applications, vehicle subsystems or the vehicle behaviour in its entirety. For the purpose of traffic simulations, where a large number of vehicles and other elements of the road network are simulated, implementing a highly complex vehicle model would greatly affect the performance of the simulation. The complexity of the vehicle model would entail a higher computation time of the system, making it unsuitable for any real time application. There in lies the trade-off indesigning a model that is both fast and accurate. The majority of the vehicle models that have been designed are either domain specific, highly complex or generalized. Thus, in this thesis, two class specific vehicles’ kinematic models with good accuracy and low computation time are presented. Two different modelling paradigms have been adopted to design and test these models. The results, challenges and limitations that pertain to these paradigms are also presented and discussed. The results show the feasibility of the proposed kinematic models.
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Tran, Xuan-Thien Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Modelling and simulation of electronically controlled diesel injectors." Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2003. http://handle.unsw.edu.au/1959.4/19278.
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The study presents a one-dimensional, transient and compressible flow models of a commercial Common Rail Injector (CRI) and a prototype of a single-fuel Hydraulically actuated Electrically controlled Unit Injector (HEUI) developed at the University of New South Wales (UNSW) in conjunction with local industry. The unique feature of the UNSW HEUI is the fact that it uses diesel fuel as the driver for pressure amplification within the unit injector. The work undertaken is part of a wider study aimed at optimization of the design of diesel injectors for dual-fuel systems to reduce green house gas emissions. The contribution of this thesis is the development of the model of the UNSW HEUI injector, which can be used to investigate possible modifications of the injector for its use in dual-fuel injection systems. The developed models include electrical, mechanical and hydraulic subsystems present in the injectors. They are based on Kirchhoff??s laws, on the mass and momentum conservation equations and on the equilibrium of forces. The models were implemented in MATLAB/SIMULINK graphical software environment, which provides a high degree of flexibility and allows simulation of both linear and nonlinear elements. The models were used to perform sensitivity analysis of both injectors. The sensitivity analysis has revealed that the temperature of the solenoid coil is one of the critical parameters affecting the timing and the quantity of the fuel injection of both injectors. Additional critical parameters were found to be the dimensions of the piston of the CRI, the stiffness of the needle spring of the HEUI and the dimensions of the intensifier of the HEUI. The models also revealed that in the case of pilot injections the speed of the solenoid is the major limiting factor of the performance. The developed models provide better understanding of the issues and limitations of the injectors. They give detailed insight into their working principles. The investigations of the models permit making quantitative analysis of the timing of the HEUI solenoid and to evaluate the proposed change of the direction of the pressure acting on the HEUI solenoid plunger.
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Merrett, Geoff V. "Energy- and information-managed wireless sensor networks : modelling and simulation." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/65002/.
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Wireless Sensor Networks (WSNs) allow the remote and distributed monitoring of parameters in their deployed environment. WSNs are receiving increasing research interest, due to their ability to enable a wide range of applications, and their potential to have a major impact on ubiquitous computing. Many research challenges are encountered in retaining a useful network lifetime under constrains imposed by the limited energy reserves that are inherent in the small, locally-powered sensor nodes. This research addresses some of these challenges through the development and evaluation of energy- and information-managed algorithms leading to increased network lifetime. The first contribution of this research is the development of an Information manageD Energy-aware ALgorithm for Sensor networks with Rule Managed Reporting (IDEALS/RMR). IDEALS/RMR is an application-independent, localised system to control and manage the degradation of a network through the positive discrimination of packets. This is achieved by the novel combination of energy management (through IDEALS) and information management (through RMR) which increases the network lifetime at the possible expense of often trivial data. IDEALS/RMR is particularly suited to applications where sensor nodes are small, energy constrained, embedded devices particularly those that feature energy harvesting) that are required to report data in an unassisted fashion. The second contribution of this research is the analysis of various environmental and physical aspects of WSNs, and the effect that they have on the operation of nodes and networks. These aspects include energy components (stores, sources and consumers), sensing devices, wireless communication, and timing; these aspects are independently modelled and, through simulation, their effect on the operation of the network is quantified. The third contribution of this research is the evaluation of IDEALS/RMR using a simulator that has been specifically developed to integrate both the proposed environmental and physical models, and a novel node architecture that facilitates structured software design. A scenario depicting the use of a WSN to monitor pump temperature in a water pumping station is simulated, and highlights the benefits of the developed algorithms.
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Koutsoukis, Nikitas-Spiros. "Decision modelling and information systems : the interaction of information and decision technologies." Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263519.
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