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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Developing a systematic methodology to build a systems dynamics model for assessment of non-technical risks in power plants

Al Mashaqbeh, S.M., Munive-Hernandez, J. Eduardo, Khan, M. Khurshid, Al Khazaleh, A. 25 November 2020 (has links)
Yes / In a dynamic business environment like the energy sector, power plants face several complex risks, including both technical and non-technical risks. These risks are not isolated, as their impact may affect a series of interrelated risks. Those risks may change with time, which in turn, makes the strategic decision-making process less effective. Understanding the dynamic behaviour of a complex system is very important to achieve a more sustainable overall performance of the power plants. Thus, it is important to further develop a systematic risk assessment methodology that could help to identify and analyse the interdependencies among risks and to understand the dynamics of these risks in complex systems. This paper develops a system dynamics (SD) methodology to support the development of risk assessment models. This paper highlights the environmental perspective. The first step to develop a SD model will be applied, while the final SD model will be discussed in another paper.
12

A system dynamics simulation model for environmental risk assessment at strategic level in power plants

Al Mashaqbeh, S.M., Munive-Hernandez, J. Eduardo, Khan, M. Khurshid, Al Khazaleh, A. 25 November 2020 (has links)
Yes / In a constantly changing business environment, a systematic approach is needed for risk assessment in order to allow for a more long-term strategic view. The System Dynamics (SD) modelling technique can be applied as an effective approach to understand the dynamic behaviour of a system over time. This understanding can be subsequently explicitly reflected on policies, strategic plans and operational procedures. This paper presents a SD model to assess environmental risks in power plants. The model helps to understand the long-term behaviour of the system under study. A questionnaire and focus group interviews have been conducted to understand the relationship among various risks. The SD model has been validated with two power plants in the Middle East. The developed model highlighted the impact of environmental risks on the performance of power plants. Although the SD model focuses on risk assessment in power plants, it can be easily adapted to other industry sectors.
13

Context aware pre-crash system for vehicular ad hoc networks using dynamic Bayesian model

Aswad, Musaab Z. January 2014 (has links)
Tragically, traffic accidents involving drivers, motorcyclists and pedestrians result in thousands of fatalities worldwide each year. For this reason, making improvements to road safety and saving people's lives is an international priority. In recent years, this aim has been supported by Intelligent Transport Systems, offering safety systems and providing an intelligent driving environment. The development of wireless communications and mobile ad hoc networks has led to improvements in intelligent transportation systems heightening these systems' safety. Vehicular ad hoc Networks comprise an important technology; included within intelligent transportation systems, they use dedicated short-range communications to assist vehicles to communicate with one another, or with those roadside units in range. This form of communication can reduce road accidents and provide a safer driving environment. A major challenge has been to design an ideal system to filter relevant contextual information from the surrounding environment, taking into consideration the contributory factors necessary to predict the likelihood of a crash with different levels of severity. Designing an accurate and effective pre-crash system to avoid front and back crashes or mitigate their severity is the most important goal of intelligent transportation systems, as it can save people's lives. Furthermore, in order to improve crash prediction, context-aware systems can be used to collect and analyse contextual information regarding contributory factors. The crash likelihood in this study is considered to operate within an uncertain context, and is defined according to the dynamic interaction between the driver, the vehicle and the environment, meaning it is affected by contributory factors and develops over time. As a crash likelihood is considered to be an uncertain context and develops over time, any usable technology must overcome this uncertainty in order to accurately predict crashes. This thesis presents a context-aware pre-crash collision prediction system, which captures information from the surrounding environment, the driver and other vehicles on the road. It utilises a Dynamic Bayesian Network as a reasoning model to predict crash likelihood and severity level, whether any crash will be fatal, serious, or slight. This is achieved by combining the above mentioned information and performing probabilistic reasoning over time. The thesis introduces novel context aware on-board unit architecture for crash prediction. The architecture is divided into three phases: the physical, the thinking and the application phase; these which represent the three main subsystems of a context-aware system: sensing, reasoning and acting. In the thinking phase, a novel Dynamic Bayesian Network framework is introduced to predict crash likelihood. The framework is able to perform probabilistic reasoning to predict uncertainty, in order to accurately predict a crash. It divides crash severity levels according to the UK department for transport, into fatal, serious and slight. GeNIe version 2.0 software was used to implement and verify the Dynamic Bayesian Network model. This model has been verified using both syntactical and real data provided by the UK department for transport in order to demonstrate the prediction accuracy of the proposed model and to demonstrate the importance of including a large amount of contextual information in the prediction process. The evaluation of the proposed system delivered high-fidelity results, when predicting crashes and their severity. This was judged by inputting different sensor readings and performing several experiments. The findings of this study has helped to predict the probability of a crash at different severity levels, accounting for factors that may be involved in causing a crash, thereby representing a valuable step towards creating a safer traffic network.
14

Predicting Voltage Abnormality Using Power System Dynamics

Beeravolu, Nagendrakumar 20 December 2013 (has links)
The purpose of this dissertation is to analyze dynamic behavior of a stressed power system and to correlate the dynamic responses to a near future system voltage abnormality. It is postulated that the dynamic response of a stressed power system in a short period of time-in seconds-contains sufficient information that will allow prediction of voltage abnormality in future time-in minutes. The PSSE dynamics simulator is used to study the dynamics of the IEEE 39 Bus equivalent test system. To correlate dynamic behavior to system voltage abnormality, this research utilizes two different pattern recognition methods one being algorithmic method known as Regularized Least Square Classification (RLSC) pattern recognition and the other being a statistical method known as Classification and Regression Tree (CART). Dynamics of a stressed test system is captured by introducing numerous contingencies, by driving the system to the point of abnormal operation, and by identifying those simulated contingencies that cause system voltage abnormality. Normal and abnormal voltage cases are simulated using the PSSE dynamics tool. The results of simulation from PSSE dynamics will be divided into two sets of training and testing set data. Each of the two sets of data includes both normal and abnormal voltage cases that are used for development and validation of a discriminator. This research uses stressed system simulation results to train two RLSC and CART pattern recognition models using the training set obtained from the dynamic simulation data. After the training phase, the trained pattern recognition algorithm will be validated using the remainder of data obtained from simulation of the stressed system. This process will determine the prominent features and parameters in the process of classification of normal and abnormal voltage cases from dynamic simulation data. Each of the algorithmic or statistical pattern recognition methods have their advantages and disadvantages and it is the intention of this dissertation to use them only to find correlations between the dynamic behavior of a stressed system in response to severe contingencies and the outcome of the system behavior in a few minutes into the future.
15

Coordenação em logística humanitária: análise por dinâmica de sistemas. / Coordination in humanitarian logistics: analysis with system dynamics.

Costa, Otávio Augusto Fernandes 05 November 2015 (has links)
Desastres são eventos complexos que exigem esforços de múltiplos atores para assistirem suas vítimas em tempo hábil a minimizar as perdas de vidas e os custos sociais e materiais da região afetada. Esta dependência de ação entre diferentes atores cria entre eles uma relação de interdependência no que tange o sucesso da operação de resposta. Este trabalho tem como objetivo analisar o problema da coordenação das atividades logísticas em uma operação humanitária utilizando Dinâmica de Sistemas como ferramenta de simulação e análise para verificar como os incentivos e impedimentos à coordenação interagem dinamicamente no ambiente humanitário e como sua estrutura de causa e efeito resulta em comportamentos com impactos e intensidades diferentes daqueles desejados pelos atores envolvidos. Assim, o objetivo específico deste trabalho é desenvolver um modelo de simulação que auxilie na compreensão do problema além de utilizá-lo para sugerir ferramentas que favoreçam o direcionamento do comportamento do sistema às metas de efetividade da ajuda humanitária exigidas pelos múltiplos atores envolvidos nesta. O desenvolvimento do trabalho segue uma estrutura multidisciplinar, buscando o necessário rigor do entendimento do problema tanto na análise da literatura quanto na formulação do modelo e sua utilização. / Disasters are complex events which require efforts from multiple actors to assist their victims on a timely manner to minimize life losses and social cost at the affected region. This action dependence between different actors rise an interdependence relation among them related to the response operation success. This work aims to analyse the problem of coordination of logistics activities in a humanitarian operation using System Dynamics as a simulation and analysis tool in order to verify how the drives and impediments to coordination dynamically interact in a humanitarian context and how its structure of cause and effect results in behaviors with different impact and intensity from those desired by involved actors. Therefore, the specific goal of this work is to develop a simulation model that support the problem understanding and apply it to suggest tools with potential to drive the system behavior towards the effectiveness goals required by the multiple actors in this environment. The development follows a cross-sectorial structure, willing to apply the necessary comprehension of the problem both in the literature review and in the model formulation and application.
16

[en] THE DYNAMICS IN A LARGE SCALE TECHNOLOGY PROJECT / [pt] A DINÂMICA EM UM PROJETO DE TECNOLOGIA DE GRANDE PORTE

FABIANO SANNINO 24 July 2006 (has links)
[pt] Este trabalho apresenta um estudo de Dinâmica de Sistema como uma ferramenta de apoio às decisões da gerência de um projeto, procurando demonstrar sua utilização e aplicação em um projeto de implementação tecnológica de grande porte. O trabalho visa possibilitar que a gestão do projeto possua uma ferramenta de análise que proporcione a antecipação das interferências existentes nos projetos, como a necessidade de adição de recursos, ingerência nas decisões do projeto, alterações de escopo e solicitação de atividades adicionais não relacionadas diretamente ao projeto. A análise da dinâmica requer a manipulação de muitas variáveis, necessitando de ferramentas que auxilie a gerência do projeto na sua visão e compreensão do projeto como um todo. Com a técnica proposta, gerentes, tomadores de decisão e gestores em geral poderão analisar as variáveis de um processo e suas dependências no projeto. Inicialmente, o trabalho apresenta uma parte teórica relacionada à Dinâmica de Sistemas apresentando um breve histórico da técnica e informações conceituais. Em seguida discorre sobre implementações de projetos de Enterprise Resource Planning (ERP), suas principais características, modelos conceituais, fases, principais produtos existentes e estruturação da equipe necessária para o projeto. Seqüencialmente apresentamos os principais modelos causais e formais de gestão de projetos, realizando uma aplicação baseada nos conceitos de implementação de ERP, demonstrando o funcionamento das principais influências existentes. / [en] This work presents a study of the System Dynamic as a support tool for decisions of the project leadership, demonstrating its use and application in a large-scale technology implementation project. Its objective is to make possible for the project management to have an analysis tool that provides the anticipation of the projects existent interferences, such as the need of additional resources, project decisions failures, scope changes, requests for additional activities not directly related to the project. The dynamic analysis requires the manipulation of many variables and needs a tool that supports the project leadership in their vision and better understanding of the overall project. With the proposed technique, project leadership, decision makers and managers in general can analyze the variables of a process and their dependencies. First, the work describes the theory related to System Dynamic, presenting a brief technique history and conceptual information. After that, it explains about Enterprise Resource Planning (ERP) implementation projects, their main characteristics, conceptual models, phases, main products and the required organizational structure. Afterwards, it introduces the main project management hard (formal) and soft (causal) models, applying the system dynamic based on the ERP implementation concepts and demonstrating the existing influences.
17

A case study of the analyze of dynamic salary strategy in vehicle industry

Liang, Chia-hao 14 July 2007 (has links)
Enterprise salary strategy should influent enterprise competition power, thinking the influence of salary strategy about job satisfaction, job efficient and productivity, turnover rate, long-term cost etc. The aim of this research is to use the method of System Dynamics and combine the balanced scorecard and strategy maps to analyze the data of case company and trace the influence between salary strategy and organize performance, further building salary decision model to connect and focus on effect to let the human resource management system toward sound to assist the enterprise make reasonable salary policy. This research is to use System Dynamics to study the interaction factors of the enterprise development which comprehend employee hiring and training, salary adjustment, motivation etc. According to each link causes the feedback to draw a causal loop map, the conclusion of this research.Using lead salary policy and competition salary policy can keep able personnel and motivation, on the contrary using lag salary policy will increase the cost and reduce productivity.The Balance Scorecard and Strategy Maps can help enterprises ¡§connection¡§and ¡§focusing¡¨ in setting the salary strategy to seek the bounder of the model, but can¡¦t unearth the side-effect of the system. The feedback map and salary decision model is really response influence of the policy, the same time finding inverse intuitive situation to search the key point for long-term goal.The result of simulate salary policy can assist decider to revise policy to reach the optimum. At last, presenting the contribution of this research.Applying and integrating human resource, salary strategy and performance management theory.By System Dynamics fulfilling causal loop map and decision model belong to the salary strategy of the case company.Seeking the suitable solution for case company salary policy.
18

Control And Simulation Studies For A Multicomponent Batch Packed Distillation Column

Ceylan, Hatice 01 August 2007 (has links) (PDF)
During the last decades, batch distillation is preferably used with an increasing demand over continuous one, to separate fine chemicals in chemical and petroleum industries, due to its advantages like, flexibility and high product purity. Consequently, packed distillation columns, with newly generated packing materials, are advantageous compared to plate columns because of their smaller holdups, resistivity to corrosive materials and their higher separation efficiencies. Also, in many industrial applications, mathematical models of distillation systems are frequently used in order to design effective control systems, to train operating personnel and to handle fault diagnostics. Thus, the main objective of this study is to develop a mathematical model for a multicomponent batch distillation column, which is used to separate mixtures at low operating pressures, packed with random packing materials. In multicomponent batch packed distillation, operation with optimum reflux ratio profile is important for efficiency to maximize the amount of the distillate with a specified concentration, for a given time. Therefore, it is also aimed to find the optimum reflux ratio profile for the multicomponent batch packed distillation column. A simulation algorithm is written with the aid of MATLAB and FORTRAN programming languages by taking into account pressure drop and variation of physical properties. The selected incremental bed height, &amp / #916 / z, to be used in the simulation program has an effect on the accuracy of the results. This is analyzed and the optimal incremental height is found to be 3.5 cm for a 1.5m bed height. The change in distillate compositions with a given constant reflux ratio is found to be similar with those of previous studies. The simulation code is also used to obtain responses in distillate compositions for different reflux ratios, condenser holdups and reboiler duties and compared with similar studies found from literature and found to be adequate. Finally, experiments are conducted to verify simulation algorithm by using a lab-scale packed distillation column for the separation of a polar mixture of ethanol and water. It is observed that, there is a good agreement between the experimental and simulation results. After the verification of dynamic model, optimum operation policy to maximize product amount is investigated numerically by using capacity factor approach. The column is operated with and without recycling of the holdups of the slop cut tanks, in order to examine the effect of recycling on capacity factor, CAP. It is observed that, recycling of the molar holdups of the slop cut tanks is resulted in a 28% increase in the separation efficiency.
19

none

Wei, Chao-shoung 22 August 2008 (has links)
Due to Cable-TV by special permission with high restriction and monopolize that the customers forced to accept without choices. The result of customer satisfaction inquire unable to understand what¡¦s the enterprise real needed and expect of customer. Formerly scholar research of relationship and interaction between customer satisfaction and enterprise by using inquire tools and result for strategy. But, That¡¦s not only one condition to judge the customer satisfaction. Such as channel content, network quality, manner of customer service ¡K etc. The multi condition to judge of customer satisfaction for the enterprise. Because, Every condition has causality of an event or a situation. It¡¦s not easy to explain the complicated with time delay. The system thinking will be solved such as this case In my research. The purpose of research : 1. Using BSC(Balance Score Card) and strategy map for case analysis in my research and find out what¡¦s critical problem in this case. 2. Using SD(System Dynamic) to simulation what is causality between system and customer satisfaction. The simulation result will verify with real system and provide for decision.
20

Coordenação em logística humanitária: análise por dinâmica de sistemas. / Coordination in humanitarian logistics: analysis with system dynamics.

Otávio Augusto Fernandes Costa 05 November 2015 (has links)
Desastres são eventos complexos que exigem esforços de múltiplos atores para assistirem suas vítimas em tempo hábil a minimizar as perdas de vidas e os custos sociais e materiais da região afetada. Esta dependência de ação entre diferentes atores cria entre eles uma relação de interdependência no que tange o sucesso da operação de resposta. Este trabalho tem como objetivo analisar o problema da coordenação das atividades logísticas em uma operação humanitária utilizando Dinâmica de Sistemas como ferramenta de simulação e análise para verificar como os incentivos e impedimentos à coordenação interagem dinamicamente no ambiente humanitário e como sua estrutura de causa e efeito resulta em comportamentos com impactos e intensidades diferentes daqueles desejados pelos atores envolvidos. Assim, o objetivo específico deste trabalho é desenvolver um modelo de simulação que auxilie na compreensão do problema além de utilizá-lo para sugerir ferramentas que favoreçam o direcionamento do comportamento do sistema às metas de efetividade da ajuda humanitária exigidas pelos múltiplos atores envolvidos nesta. O desenvolvimento do trabalho segue uma estrutura multidisciplinar, buscando o necessário rigor do entendimento do problema tanto na análise da literatura quanto na formulação do modelo e sua utilização. / Disasters are complex events which require efforts from multiple actors to assist their victims on a timely manner to minimize life losses and social cost at the affected region. This action dependence between different actors rise an interdependence relation among them related to the response operation success. This work aims to analyse the problem of coordination of logistics activities in a humanitarian operation using System Dynamics as a simulation and analysis tool in order to verify how the drives and impediments to coordination dynamically interact in a humanitarian context and how its structure of cause and effect results in behaviors with different impact and intensity from those desired by involved actors. Therefore, the specific goal of this work is to develop a simulation model that support the problem understanding and apply it to suggest tools with potential to drive the system behavior towards the effectiveness goals required by the multiple actors in this environment. The development follows a cross-sectorial structure, willing to apply the necessary comprehension of the problem both in the literature review and in the model formulation and application.

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