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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.
181

Modelagem da convergência de materiais em desastres por meio de dinâmica de sistemas. / Modelling material convergence in disasters with system dynamics.

Buzogany, Raquel Froese 06 March 2017 (has links)
O número de desastres vem aumentando a cada ano e a quantidade de pessoas afetadas por estes é cada vez maior. A convergência de materiais, que é o afluxo de grande quantidade de material ao local do desastre, é observada em muitos eventos e tem grande impacto sobre operações humanitárias; em especial, nos processos de logística humanitária, como transporte, processamento e distribuição de itens necessários no auxílio às vítimas. Devido a diversos efeitos negativos da convergência - por exemplo, o emprego de recursos humanos em tarefas não essenciais e a maior demora para distribuição de material prioritário -, é necessário estudar os fatores que a influenciam e, também, como suas consequências afetam o sistema em que se insere. Desta forma, utilizou-se o método de dinâmica de sistemas para desenvolver um modelo que permita, pela análise de diversos cenários, alcançar uma melhor compreensão sobre o fenômeno. O modelo, além de permitir testar políticas abordadas na literatura, também proporciona uma simulação para o preparo em desastres reais e, no âmbito acadêmico, é o primeiro modelo de convergência de materiais a integrar tanto variáveis quantitativas quanto qualitativas e propiciar uma análise de forma dinâmica no tempo. A partir do cenário base, o caso das inundações em São Luiz do Paraitinga em 2010, foram simulados 13 cenários com o objetivo de identificar quais políticas aumentariam a quantidade de material prioritário distribuído para suprir as necessidades das vítimas. No cenário base foram encontrados gargalos no transporte e na distribuição de materiais e a análise de sensibilidade ficou restrita a uma política, limitando a generalização do trabalho. Na implementação de políticas uma a uma, observa-se que a não admissão de material não prioritário atinge os melhores resultados, seguida pela política de realocação de recursos humanos para processamento de material prioritário. Já no caso de políticas mistas, o controle de admissão com uma maior disponibilidade de recursos é o cenário que mais se sobressai no auxílio às vítimas. / The number of disasters is increasing each year and the amount of people affected by them is also getting bigger. Material convergence, which is the influx of large amounts of material to the disaster site, is observed in many events and has a large impact on humanitarian operations; in particular in humanitarian logistics processes, such as transportation, processing and distribution of necessary items to assist victims. Due to various negative effects of the convergence - for example, the use of human resources in non-core tasks and the longer delay for priority material distribution - it is necessary to study the factors that influence it and how its consequences affect the system. In this way, the method of system dynamics was used to develop a model that allows, through the analysis of several scenarios, to reach a better understanding about the phenomenon. The model, besides allowing to test policies approached in the literature, also provides a simulation for the preparation in real disasters and, in the academic scope, it is the first model of material convergence to integrate both quantitative and qualitative variables and to provide a dynamic analysis. Based on the baseline scenario, the case of the floods in São Luiz do Paraitinga in 2010, 13 scenarios were simulated to identify which policies would increase the amount of priority material distributed to meet the needs of the victims. Analyzing the base scenario there were found bottlenecks both in the transportation and the distribution of material and, as the sensitivity analysis was restricted to only one policy, the generalization of the presented work has been limited. In implementing policies one by one, it is observed that the non-admission of non-priority material achieves the best results, followed by the policy of reallocating human resources to processing priority material. In the case of mixed policies, admission control with greater availability of resources is the most prominent scenario in assisting victims.
182

A aplicação de um modelo de simulação para o gerenciamento de projetos: um estudo de caso utilizando a dinâmica de sistemas. / The application of a simulation model to project management: a case study using system dynamics.

Santos, Aldren Montenegro dos 01 December 2006 (has links)
Esta pesquisa apresenta a Dinâmica de Sistemas como uma ferramenta complementar à modelagem tradicionalmente utilizada no gerenciamento de projetos1, demonstrando a sua aplicabilidade por meio de um estudo de caso na área de projetos de engenharia de uma organização pública de natureza militar. No desenvolvimento do estudo, são apresentados os procedimentos para elaboração, validação e testes de políticas em modelos de Dinâmica de Sistemas, bem como os conceitos fundamentais desta teoria. A partir daí, os processos envolvidos no gerenciamento de um projeto serão descritos sob o ponto de vista sistêmico com o objetivo de aplicar a metodologia apresentada. Com base nos conceitos fundamentais da Dinâmica de Sistemas, será criado um modelo para o estudo do gerenciamento de projetos de engenharia dentro de uma organização fabril no âmbito do Comando da Aeronáutica. O modelo será criado para aplicação em um estudo de caso de um projeto de modernização tecnológica de uma aeronave militar. Alguns cenários e políticas gerenciais serão explorados com o objetivo de aprimorar o conhecimento sobre o sistema real a partir do comportamento do modelo. Ao final do trabalho serão classificadas as políticas que geraram os melhores efeitos no modelo criado e serão apresentadas algumas considerações sobre a metodologia aplicada e propostas para a sua utilização em outras áreas. / This research presents the Systems Dynamics as a complementary tool for the traditional approach used in project management, by demonstrating its practical application to the engineering project management area of a public organization. During the development of this study, the fundamental concepts of the theory of System Dynamics as well as the procedures for development, validation and politics tests in system dynamics modelling are presented. By this point, the processes envolved in project management are described by the systemic point of view with the objective of application of the metodology presented. Based in the fundamental concepts of system dynamics, a model is developed for the analysis of the engineering project management area of an aircraft maintenace depot of Brazilian Air Force. This model is going to be used in a case study of an aircraft technological upgrade. Some scenarios and management politics are explored with the objective of apprimorate the knowledge of the model behaviour. By the end of this work these politics are classified by its better effects in the model developed, and some considerations about the metodology applied are going to be presented the same way as purposes to this utilization in other areas.
183

Time for change : a study of enrolment decision dynamics for admission into English secondary education

Carter, David Andrew January 2018 (has links)
Cross-sectional studies suggest a prevalence of mental health problems from the age that children change to English secondary schools but there are few longitudinal appraisals of these issues and how enrolment policies influence psychological wellbeing. This research focuses on key factors linking competition for secondary schools and family responses to such challenges to determine enrolment policies that can sustain wellbeing longer-term. Integrated, model-based multimethodology was used in this urban, case-based study. Views were induced from multi-agency, expert practitioners to agree a system dynamics concept model. Parental decision-making behaviours were deduced by survey to understand key factors for model calibration. Dynamic system sensitivities were abduced from the simulation model before comparing long-term psychosocial impacts on children from expert, policy-support suggestions. Modelling demonstrates that two principal feedback loops influence family psychosocial systems when deciding secondary schools (parent-child wellbeing reinforcement plus knowledge of schools balancing parent concerns). Exogenous competition stressors on psychosocial systems can erode parent knowledge while testing student resolve. Competition guidance to remove risk-laden school options (league table comparison) before sequencing any remaining choices by profit (school visits), are not always used deciding urban secondary schools. Instead, families lacking experience can adopt decisive styles based on parent needs alone. Given autocratic leadership, child wellbeing rapidly deteriorates when student needs cannot be met by schools. Rather than ending student-selective entrance tests or raising knowledge of schools at visits, effective multi-agency support policy helps by increasing school choice debate frequency within families to address psychosocial system imbalances. The research makes a clear, three-way contribution to knowledge. Firstly, intrinsic case study theory is enhanced by data triangulation between induced, deduced and abduced research approaches. Secondly, the system dynamics discipline is strengthened by studying compulsory school enrolment. Finally, developing practice-based policy through multi-agency groups endorses cooperative rather than unilateral solutions, for helping change lives.
184

Participatory system dynamics modelling approach to safe and efficient staffing level management within hospital pharmacies

Ibrahim Shire, Mohammed January 2018 (has links)
With increasingly complex safety-critical systems like healthcare being developed and managed, there is a need for a tool that allows us to understand their complexity, design better strategies and guide effective change. System dynamics (SD) has been widely used in modelling across a range of applications from socio-economic to engineering systems, but its potential has not yet been fully realised as a tool for understanding trade-off dynamics between safety and efficiency in healthcare. SD has the potential to provide balanced and trustworthy insights into strategic decision making. Participatory SD modelling and learning is particularly important in healthcare since problems in healthcare are difficult to comprehend due to complexity, involvement of multiple stakeholders in decision making and fragmented structure of delivery systems. Participatory SD modelling triangulates stakeholder expertise, data and simulation of implementation plans prior to attempting change. It provides decision-makers with an evaluation and learning tool to analyse impacts of changes and determine which input data is most likely to achieve desired outcomes. This thesis aims to examine the feasibility of applying participatory SD modelling approach to safe and efficient staffing level management within hospital pharmacies and to evaluate the utility and usability of participatory SD modelling approach as a learning method. A case study was conducted looking at trade-offs between dispensing backlog (efficiency) and dispensing errors (safety) in a hospital pharmacy dispensary in an English teaching hospital. A participatory modelling approach was employed where the stakeholders from the hospital pharmacy dispensary were engaged in developing an integrated qualitative conceptual model. The model was constructed using focus group sessions with 16 practitioners consisting of labelling and checking practitioners, the literature and hospital pharmacy databases. Based on the conceptual model, a formal quantitative simulation model was then developed using an SD simulation approach, allowing different scenarios and strategies to be identified and tested. Besides the baseline or business as usual scenario, two additional scenarios (hospital winter pressures and various staffing arrangements, interruptions and fatigue) identified by the pharmacist team were simulated and tested using a custom simulation platform (Forio: user-friendly GUI) to enable stakeholders to play out the likely consequences of the intervention scenarios. We carried out focus group-based survey of 21 participants working in the hospital pharmacy dispensaries to evaluate the applicability, utility and usability of how participatory SD enhanced group learning and building of shared vision for problems within the hospital dispensaries. Findings from the simulation illustrate the knock-on impact rework has on dispensing errors, which is often missing from the traditional linear model-based approaches. This potentially downward-spiral knock-on effect makes it more challenging to deal with demand variability, for example, due to hospital winter pressures. The results provide pharmacy management in-depth insights into potential downward-spiral knock-on effects of high workload and potential challenges in dealing with demand variability. Results and simulated scenarios reveal that it is better to have a fixed adequate staff number throughout the day to keep backlog and dispensing errors to a minimum than calling additional staff to combat growing backlog; and that whilst having a significant amount of trainees might be cost efficient, it has a detrimental effect on dispensing errors (safety) as number of rework done to correct the errors increases and contributes to the growing backlog. Finally, capacity depletion initiated by high workload (over 85% of total workload), even in short bursts, has a significant effect on the amount of rework. Evaluative feedback revealed that participatory SD modelling can help support consensus agreement, thus gaining a deeper understanding of the complex interactions in the systems they strive to manage. The model introduced an intervention to pharmacy management by changing their mental models on how hospital winter pressures, various staffing arrangements, interruptions and fatigue affect productivity and safety. Although the outcome of the process is the model as an artefact, we concluded that the main benefit is the significant mental model change on how hospital winter pressures, various staffing arrangements, interruptions and fatigue are interconnected, as derived from participants involvement and their interactions with the GUI scenarios. The research contributes to the advancement of participatory SD modelling approach within healthcare by evaluating its utility and usability as a learning method, which until recently, has been dominated by the linear reductionist approaches. Methodologically, this is one of the few studies to apply participatory SD approach as a modelling tool for understanding trade-offs dynamics between safety and efficiency in healthcare. Practically, this research provides stakeholders and managers, from pharmacists to managers the decision support tools in the form of a GUI-based platform showcasing the integrated conceptual and simulation model for staffing level management in hospital pharmacy.
185

Um modelo em dinâmica de sistemas para o ensino superior

Strauss, Luisa Mariele January 2010 (has links)
O ensino superior no Brasil experimentou uma rápida expansão a partir da publicação da Lei de Diretrizes e Bases (LDB) de 1996 e da flexibilização do Governo para abertura de novos cursos e instituições de ensino, impulsionado principalmente pelo setor privado. Apesar desta expansão, o Brasil ainda não atingiu a meta prevista no Plano Nacional de Educação: 30% de jovens de 18 a 24 anos no ensino superior. Além disso, a procura por cursos de graduação apresenta sinais de retração, caracterizando um sistema com rápido crescimento inicial seguido de estagnação. O presente trabalho propõe compreender a dinâmica desse sistema por meio da construção de um modelo em Dinâmica de Sistemas, analisando o ensino superior de graduação. O modelo considera regulação, metas, demanda, oferta e, especialmente, o equilíbrio entre setores público e privado. A metodologia de trabalho consistiu nas etapas de definição do problema, formulação da hipótese dinâmica, construção do modelo de simulação, validação e experimentação. Esta etapa resultou em análise de cenários alternativos para o ensino superior de graduação brasileiro. Como resultado, o trabalho permite analisar o comportamento possível das principais variáveis em cada cenário e fazer especulações sobre variáveis não mensuradas no sistema real. / Higher education in Brazil has experienced a rapid expansion since the publication of the Directives and Bases Law (LDB) in 1996 and the pliability of the Government for the launching of new programs and educational institutions, mainly driven by the private sector. Despite this expansion, Brazil has not yet reached the aim expected in the Education National Plan: 30% of young people from 18 to 24 years old in higher education. Moreover, the demand for undergraduate programs presents signs of retraction, characterizing a system with fast initial growth followed by stagnation. This thesis proposes to understand the dynamics of this system by developing a model in System Dynamics, analyzing the undergraduate higher education. The model considers regulation, aims, demand, supply and especially the balance between public and private sectors. The methodology consists in the stages of problem definition, formulation of the dynamic hypothesis, development of the simulation model and in the validation and scenario testing. This step resulted in an analysis of alternative scenarios for the Brazilian undergraduate higher education. As a result, this thesis allows one to analyze the possible behavior of key variables in each scenario and to make observations on the variables that are not defined in the real system.
186

Modelo para análise da inserção de pequenas fontes solares fotovoltaicas em sistemas de distribuição : uma abordagem multivariável

Baumgarten, Cristiano January 2016 (has links)
Este trabalho apresenta um modelo para análise do comportamento dinâmico da inserção da micro e minigeração solar fotovoltaica em redes de distribuição de energia elétrica. O modelo é desenvolvido com aplicação da técnica de análise e modelagem de Dinâmica de Sistemas, resultando em uma ferramenta eficiente para o auxílio na tomada de decisão e na elaboração de políticas quanto ao estímulo dos sistemas de geração fotovoltaica. O modelo desenvolvido testa as políticas, através da construção de cenários, que possibilitam ao consumidor à tomada de decisão, quanto ao investimento na micro geração, a partir dos contextos regulatório e de mercado. O modelo avalia a tomada de decisão dos consumidores quanto ao investimento em fontes de micro geração fotovoltaica englobando não apenas fatores técnicos e econômicos, mas também fatores sociais e ambientais. O modelo fornece, também, uma projeção do potencial de energia fotovoltaica associada à micro e minigeração, e permite verificar a ação da “death spiral” (espiral da morte) sobre o faturamento de distribuidoras. Diversos incentivos são implementados e investigados no sentido de promover essa tecnologia. Os resultados obtidos mostram que políticas como a criação da tarifa prêmio, em conjunto com a redução do ICMS incidente sobre a energia gerada pelo prosumidor (consumidor/gerador) e a veiculação publicitária sobre a micro geração podem alavancar o uso destas fontes no contexto energético global. / This dissertation presents an innovative method for analyzing the dynamic behavior of a multi-variable system that models the several aspects of photovoltaic solar micro generation penetration in distribution networks. The proposed model is based on the System Dynamics approach in order to test the policies through multi-criterial scenarios, including the consumer's decision-making to invest in renewable sources considering regulatory and market contexts. In addition to technical and economic aspects, social and environmental criteria are also taken into account in modelling the consumer’s decision-making. The model also provide a projection of energy photovoltaic associated with micro and minigeneration and allows to verify the action of detah spiral on distributors revenue. Several incentives are proposed and evaluated as alternatives to promote photovoltaic generation the technology. The presented model has shown as an effective tool to support the decision-making for both consumers and policymakers. Results show that policies such as feed-in tariff along with the reduction of Value-Added Tax (VAT) on generated energy may greatly promote the use of these sources in the energy market.
187

Systémový model řízení profesionální firmy / System Management Model of a Professional Service Firm

Hubík, Tomáš January 2012 (has links)
In the presented work I devote to creating a computer model of a professional service firm using the theory of business modeling. The whole model was programmed using the application Vensim. Another part of this work was to use this model to answer some key questions about the professional service firms. I dealt with the issue of optimal volume and optimal size of potential orders. I have also studied the influence of marketing and employee productivity on business performance. Another part of the work was to find patterns in employees career growth and to monitor sales and quality of projects delivery. I also determined the size and characteristics of critical mass. Such a model could then be used to better understand patterns of companies in the professional services industry and we can use it to manage the company more effectively in this environment.
188

Strategic risk management for tidal current and wave power projects

Bucher, Ralf January 2018 (has links)
Tidal current and wave power, as emerging forms of renewable generation, represent innovations that are confronted by significant technological and financial challenges. Currently, the marine energy sector finds itself in a decisive transition phase having developed full-scale technology demonstrators but still lacking proof of the concept in a commercial project environment. After the decades-long development process with larger than expected setbacks and delays, investors are discouraged because of high capital requirements and the uncertainty of future revenues. Although ideas for improving the investment climate can be found, there is a lack of well-founded arguments and coordinated strategies to work towards a breakthrough in the marine energy market. The objective of this research is to provide stakeholder-specific prioritised strategy options for de-risking the commercialisation of tidal current and wave power technologies. A key principle applied is to integrate a wide knowledge spectrum comprising the technology, policy and financing sectors and to compile the information in a holistic and transparent manner. To gain a broad understanding of the characteristics of presently ongoing marine energy activities and the correlated strategic planning, a comprehensive survey was conducted. Based on this multidisciplinary attempt, an all-encompassing appraisal was possible by avoiding over-concentration on stakeholder-specific views or interests. System dynamics modelling was employed to develop a series of cause-effect relationship diagrams of the key interactions and correlations in the field. It was revealed that the circular relationship between two major risks for array-scale projects - reliability and funding - requires coordinated action to overcome. As funding is necessary for improving system reliability (and vice-versa), showcasing 'array-scale success' was identified as the game-changing milestone towards commercial generation. Furthermore, it was found that a number of comparably competent manufacturing firms is required to implement major marine energy projects. This would result from fostering a multi-company market breakthrough concept, based on intensified knowledge sharing and trustful collaborative interaction between competitors. Additionally, effective separation of complexity into 'detail' and 'dynamically complex' constituents was found to be fundamental for identifying long-term, effective solutions. It is decisive to accept this primary classification, as measures appropriately applied on one type of complexity can be counterproductive if applied on the other. Most of the available planning tools and analytical methods do not address the management of dynamic complexity, necessary in innovative environments where flexibility and tolerance of vagueness are indispensable. Successful application of several strategies to deal with both types of complexity in comparable innovation-driven environments was considered suitable for de-risking the commercialisation of marine energy. The challenges for strategy-finding in a demandingly complex and increasingly dynamic environment are addressed in this research by exploiting a case-specific expert knowledge database. The structured information compression and subsequent strategy-finding process is realised based on calculated rankings of impact factors by systems dynamics software and substantiated by representative interview statements. The analysis makes use of multi-level expert knowledge and the application of a control-loop-based methods. The systems approach as applied in this research comprises the combination of interview-based (bottom-up learning) processes and the application of prioritised strategy options in the form of concerted management action (top-down planning). The approach of processing multi-level interview data by system dynamics modelling represents a powerful method to detect and assess ongoing developments and thus to advance strategy-finding. The systematic and unbiased approach to identify the top-level drivers for commercialising marine energy supports the long-term creation of investor confidence, based on a concept of transparency and credibility.
189

BAYESIAN-INTEGRATED SYSTEM DYNAMICS MODELLING FOR PRODUCTION LINE RISK ASSESSMENT

Punyamurthula, Sudhir 01 January 2018 (has links)
Companies, across the globe are concerned with risks that impair their ability to produce quality products at a low cost and deliver them to customers on time. Risk assessment, comprising of both external and internal elements, prepares companies to identify and manage the risks affecting them. Although both external/supply chain and internal/production line risk assessments are necessary, internal risk assessment is often ignored. Internal risk assessment helps companies recognize vulnerable sections of production operations and provide opportunities for risk mitigation. In this research, a novel production line risk assessment methodology is proposed. Traditional simulation techniques fail to capture the complex relationship amongst risk events and the dynamic interaction between risks affecting a production line. Bayesian- integrated System Dynamics modelling can help resolve this limitation. Bayesian Belief Networks (BBN) effectively capture risk relationships and their likelihoods. Integrating BBN with System Dynamics (SD) for modelling production lines help capture the impact of risk events on a production line as well as the dynamic interaction between those risks and production line variables. The proposed methodology is applied to an industrial case study for validation and to discern research and practical implications.
190

The impacts of climate change on cattle water demand and supply in Khurutshe, Botswana

Masike, Sennye January 2007 (has links)
The primary question that the thesis investigates is: what impacts could climate change have on cattle water demand and supply in Khurutshe, Botswana. This thesis is pursued in light of the fact that there is a lack of knowledge on climate change and cattle water demand and supply. Thus, this thesis aims at filling the gap in knowledge on climate change and cattle water resources in Botswana and other semi-arid environments. A cattle water demand and supply model is developed to investigate the primary question of the thesis. The model is driven by rainfall and temperature over time as these variables largely determine cattle water supply and demand, respectively. Climate scenarios for 2050 are constructed using SimCLIM (developed by the International Global Change Institute of the University of Waikato) based on HadCM3 and CSIRO Mk2 General Circulation Models (GCMs). Three Special Report on Emission Scenarios (SRES) are used: A1B, A1FT and A1T. These emission scenarios were selected based on their coverage for possible future Greenhouse Gas emissions (GHG). Climate scenarios show that by 2050 the temperature for the Khurutshe area could increase by as much as 3 oC depending on the GCM and SRES emission scenario and that there could be a decline in rainfall of up to 14% per month. CSIRO Mk2 displayed the maximum decline in rainfall while HadCM3 depicted the maximum increase in temperature. The model is implemented in the Khurutshe of the Kgatleng District, Botswana. The results reported are for Masama Ranch and also for the whole of the Khurutshe area. The results show that climate change could lead to an annual increase of more than 20% in cattle water demand by 2050 due to an increase in temperature. In addition, climate change could lead to a decline in the contribution of surface pan water to cattle water supply. Overall, there could be an increase in abstraction of groundwater for cattle by 2050 due to an increase in demand and a decline in forage water content and surface pan water. Observations in semi-arid environments of Africa indicate that farmers encounter problems of declining borehole yields and local depletion in groundwater in summer and drought years when demand peaks. In addition, it has been observed that during drought more cattle are lost as a result of lack of water, particularly for those whose cattle are reliant on surface water. Thus, the results from this study indicate that climate change could enhance this problem. In the thesis I have shown the importance of integrating climate change impacts on water demand and supply when assessing water resources, which has been ignored in the past. Some of the policy options that are discussed are tradable pumping permits for controlling abstraction and allocation issues in the Khurutshe aquifer and, controlling stocking numbers. This is in recognition of the fact that climate change could result in more reliance on groundwater for both cattle farming and urban water supply hence compromising sustainability and allocation issues especially for the Khurutshe aquifer which is earmarked to supply the city of Gaborone and surrounding villages in drought periods.

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