A modelagem matemática da qualidade da água de rios constitui-se em uma ferramenta indispensável ao planejamento e à gestão dos recursos hídricos. No entanto, os modelos atuais disponíveis para a simulação da qualidade da água, como o QUAL2K, apresentam limitações estruturais e funcionais. Com o intuito de oferecer uma ferramenta que elimine essas deficiências, foi desenvolvido um modelo para a simulação da qualidade da água em rios em regime não-permanente, utilizando o software Vensim PLE, que também opera em regime permanente. O modelo desenvolvido simula dezoito variáveis da qualidade da água (oxigênio dissolvido, demanda bioquímica de oxigênio carbonácea, nitrogênio orgânico, nitrogênio amoniacal, nitrito, nitrato, fósforo orgânico e inorgânico, sólidos inorgânicos, fitoplâncton, zooplâncton, algas de fundo, detritos, coliformes totais, alcalinidade, carbono inorgânico total, pH e temperatura), bem como o metano e as formas de nitrogênio e fósforo presentes na camada aeróbia e anaeróbia do sedimento. Diversos cenários foram gerados para a realização de simulações computacionais utilizando o modelo desenvolvido neste estudo, o programa QUAL2E, o QUAL2K e quando possível, soluções analíticas. Os resultados das simulações obtidos com este modelo, em regime permanente, ajustaram-se bem aos modelos da família QUAL. As simulações em regime não-permanente também apresentaram bons resultados, visto que a solução numérica produzida pelo modelo seguiu a tendência geral da solução analítica. / The water-quality modeling is an indispensable tool for the water resource planning and management. However, the current available models for the simulation of water-quality, as the QUAL2K, present structural and functional limitations. With the purpose of offering a tool that facing those deficiencies, a model for time-variable simulation of the rivers water quality, using the software Vensim PLE® was developed. The model developed simulates eighteen water-quality variables (oxygen dissolved, carbonaceous BOD, organic nitrogen, ammonia, nitrite, nitrate, organic and inorganic phosphorus, inorganic solids, phytoplankton, zooplankton, bottom algae, coliforms, alkalinity, total inorganic carbon, pH and temperature),in addition to methane and the nitrogen and phosphorus forms existing in the aerobic and anaerobic layer of the sediment. Several scenarios were built to accomplish computational simulation using the model developed in this work, the program QUAL2E, the QUA2K, and when possible, analytical solutions. The results obtained, with this model, adjusted well to the results generated by the QUAL family models, at steady-state. The simulations at unsteady state presented good results since the numerical solutions followed the general tendency of the analytic solution.

A modelagem matemática da qualidade da água de rios constitui-se em uma ferramenta indispensável ao planejamento e à gestão dos recursos hídricos. No entanto, os modelos atuais disponíveis para a simulação da qualidade da água, como o QUAL2K, apresentam limitações estruturais e funcionais. Com o intuito de oferecer uma ferramenta que elimine essas deficiências, foi desenvolvido um modelo para a simulação da qualidade da água em rios em regime não-permanente, utilizando o software Vensim PLE, que também opera em regime permanente. O modelo desenvolvido simula dezoito variáveis da qualidade da água (oxigênio dissolvido, demanda bioquímica de oxigênio carbonácea, nitrogênio orgânico, nitrogênio amoniacal, nitrito, nitrato, fósforo orgânico e inorgânico, sólidos inorgânicos, fitoplâncton, zooplâncton, algas de fundo, detritos, coliformes totais, alcalinidade, carbono inorgânico total, pH e temperatura), bem como o metano e as formas de nitrogênio e fósforo presentes na camada aeróbia e anaeróbia do sedimento. Diversos cenários foram gerados para a realização de simulações computacionais utilizando o modelo desenvolvido neste estudo, o programa QUAL2E, o QUAL2K e quando possível, soluções analíticas. Os resultados das simulações obtidos com este modelo, em regime permanente, ajustaram-se bem aos modelos da família QUAL. As simulações em regime não-permanente também apresentaram bons resultados, visto que a solução numérica produzida pelo modelo seguiu a tendência geral da solução analítica. / The water-quality modeling is an indispensable tool for the water resource planning and management. However, the current available models for the simulation of water-quality, as the QUAL2K, present structural and functional limitations. With the purpose of offering a tool that facing those deficiencies, a model for time-variable simulation of the rivers water quality, using the software Vensim PLE® was developed. The model developed simulates eighteen water-quality variables (oxygen dissolved, carbonaceous BOD, organic nitrogen, ammonia, nitrite, nitrate, organic and inorganic phosphorus, inorganic solids, phytoplankton, zooplankton, bottom algae, coliforms, alkalinity, total inorganic carbon, pH and temperature),in addition to methane and the nitrogen and phosphorus forms existing in the aerobic and anaerobic layer of the sediment. Several scenarios were built to accomplish computational simulation using the model developed in this work, the program QUAL2E, the QUA2K, and when possible, analytical solutions. The results obtained, with this model, adjusted well to the results generated by the QUAL family models, at steady-state. The simulations at unsteady state presented good results since the numerical solutions followed the general tendency of the analytic solution.

Modelos matemáticos são representações ou interpretações simplificadas da realidade ou uma representação de um fragmento de um sistema. As simulações destes fenômenos auxiliam na tomada de decisão da parte interessada, ou seja, aqueles que trabalham em uma área. A modelagem de um sistema de processos anaeróbios, como o tratamento de um efluente em reatores UASB (Upflow Anaerobic Sludge Blanket), auxilia os gestores destes sistemas na operação e no controle de estabilidade. O modelo ADM1 (Anaerobic Digestion Model Nº 1), criado pela IWA em 2002, simula o comportamento da digestão anaeróbia. Entretanto, este modelo não considera a hidrodinâmica do sistema como fator relevante no desempenho do processo. O estudo do comportamento do escoamento de efluente no interior de um reator é possível através de ensaios de hidrodinâmica. Estes são conduzidos, majoritariamente, por meio de experimentos laboratoriais que se utilizam de traçadores que, por sua vez, podem resultar em custos elevados. A Dinâmica de Fluidos Computacional (DFC) é uma área na mecânica dos fluidos que utiliza análises numéricas e algoritmos para solucionar e analisar problemas relacionados com escoamento de fluidos. Os softwares de DFC que resolvem estes algoritmos podem ser utilizados na simulação dos ensaios de hidrodinâmica. Foi utilizado nesta tese o pacote de DFC Ansys®, em que o software CFXTM foi o escolhido para realizar as simulações de escoamento. Um dos objetivos desta tese foi a validação desta simulação por meio de ensaios de laboratório e ensaios virtuais em um reator UASB em escala de bancada (1,5 L). Resultou-se, dessa comparação, em dados estatisticamente similares (teste U de Mann-Whitney), proporcionando validação do método. Após esta validação, simulou-se o mesmo tipo de ensaio para um reator UASB em formato de \"Y\" (escala piloto; 119,3 L). Foram simuladas três condições operacionais, em que se variou a vazão de alimentação, sendo esta função da carga orgânica volumétrica aplicada ao lodo (COV). As COV foram 7,5, 12,5 e 17,5 kgDQO m-3d-1. Obteve-se N-CSTR (número de reatores de mistura completa em série) igual a 11, 10 e 10 unidades para cada condição, respectivamente. A ferramenta de Dinâmica de Sistemas utiliza-se de uma abordagem de entendimento de modelos complexos e, por meio de ciclos de retroalimentação (feedback) e estoques e fluxos (stocks and flows), demonstra que modelos aparentemente simples podem ser muito complexos. Existem vários softwares de Dinâmica de Sistemas e neles podem ser implementados os mais variados modelos. Utilizando o software Vensim PLE®, modelou-se a digestão anaeróbia do ácido acético por meio de equações baseadas no modelo de cinética enzimática de Monod e no modelo de digestão anaeróbia ADM1. Considerou-se as taxas de consumo de substrato e crescimento de biomassa bacteriana, a inibição causada pelo pH e a quantidade de alcalinizante necessária para atingir o pH desejado deste meio. De forma complementar, integrou-se um modelo de cálculo de alcalinidade do meio e, desta forma, foi possível determinar as concentrações de cada espécie que confere alcalinidade ao meio, considerando o equilíbrio do carbonato. Denominou-se esta modelação (DFC e dinâmica de sistemas) de Modelo Hidro-bioquímico do processamento anaeróbio. Os resultados obtidos por Del Nery et al. (2016) corroboraram com os obtidos nesta tese. / Mathematical models are representations and simplified interpretations of reality or a representation of a system fragment. The modeling of anaerobic processes, such as wastewater treatment in UASB (Upflow Anaerobic Sludge Blanket) reactors, helps managers in the operation of these systems and stability control. The Anaerobic Digestion Model No. 1 (ADM1), created by IWA in 2002, simulates the behavior of anaerobic digestion. However, this model does not consider the system hydrodynamics as a relevant factor in the performance of the process. The effluent flow behavior studies on the reactor inside is possible by hydrodynamic tests. These are conducted through laboratory experiments that uses tracers and this can result in high costs in the conduct of the tests. The Computational Fluid Dynamics (CFD) is an area in fluid mechanics that uses numerical analysis and algorithms to solve and analyze problems related to fluid flow. CFD software can be used to simulate the hydrodynamics assays. It was used in this thesis Ansys® workbench, wherein the CFXTM software was chosen to perform CFD flow simulations. One objective of this thesis was to validate the CFD simulation through laboratory and virtual testing in a UASB bench scale (1.5 liters). In this comparison, it resulted in similar data statistically (Mann-Whitney U test). After validation of the hydrodynamic test, was simulated the same type of assay for an UASB reactor \"Y\" shaped (pilot scale; = 82.27 liters working volume). The test result was N-CSTR (number of complete mixing reactors in series) equal to 4 units, considering a 103.9 liters per day of feed flow (hydraulic retention time of 19 hours). The system dynamics tool makes use of understanding approach of complex models and, through feedback loops and stocks and flows, shows that seemingly simple models can be very complex. There are several system dynamics software and most varied models can be implemented. Using Vensim PLE® software, it was developed an acetate anaerobic digestion model (in this case acetic acid) via equations based on the Monod and ADM1 model. It was considered for the hydro-biochemical modeling, substrate consumption and growth of bacterial biomass rates, the pH inhibition and the amount of alkalizing necessary to achieve the desired pH of the medium. Complementarily, integrated into a calculation alkalinity model of the medium and thus it was possible to determine the concentrations of each species imparts environment alkalinity, considering the carbonate balance.

Modelos matemáticos são representações ou interpretações simplificadas da realidade ou uma representação de um fragmento de um sistema. As simulações destes fenômenos auxiliam na tomada de decisão da parte interessada, ou seja, aqueles que trabalham em uma área. A modelagem de um sistema de processos anaeróbios, como o tratamento de um efluente em reatores UASB (Upflow Anaerobic Sludge Blanket), auxilia os gestores destes sistemas na operação e no controle de estabilidade. O modelo ADM1 (Anaerobic Digestion Model Nº 1), criado pela IWA em 2002, simula o comportamento da digestão anaeróbia. Entretanto, este modelo não considera a hidrodinâmica do sistema como fator relevante no desempenho do processo. O estudo do comportamento do escoamento de efluente no interior de um reator é possível através de ensaios de hidrodinâmica. Estes são conduzidos, majoritariamente, por meio de experimentos laboratoriais que se utilizam de traçadores que, por sua vez, podem resultar em custos elevados. A Dinâmica de Fluidos Computacional (DFC) é uma área na mecânica dos fluidos que utiliza análises numéricas e algoritmos para solucionar e analisar problemas relacionados com escoamento de fluidos. Os softwares de DFC que resolvem estes algoritmos podem ser utilizados na simulação dos ensaios de hidrodinâmica. Foi utilizado nesta tese o pacote de DFC Ansys®, em que o software CFXTM foi o escolhido para realizar as simulações de escoamento. Um dos objetivos desta tese foi a validação desta simulação por meio de ensaios de laboratório e ensaios virtuais em um reator UASB em escala de bancada (1,5 L). Resultou-se, dessa comparação, em dados estatisticamente similares (teste U de Mann-Whitney), proporcionando validação do método. Após esta validação, simulou-se o mesmo tipo de ensaio para um reator UASB em formato de \"Y\" (escala piloto; 119,3 L). Foram simuladas três condições operacionais, em que se variou a vazão de alimentação, sendo esta função da carga orgânica volumétrica aplicada ao lodo (COV). As COV foram 7,5, 12,5 e 17,5 kgDQO m-3d-1. Obteve-se N-CSTR (número de reatores de mistura completa em série) igual a 11, 10 e 10 unidades para cada condição, respectivamente. A ferramenta de Dinâmica de Sistemas utiliza-se de uma abordagem de entendimento de modelos complexos e, por meio de ciclos de retroalimentação (feedback) e estoques e fluxos (stocks and flows), demonstra que modelos aparentemente simples podem ser muito complexos. Existem vários softwares de Dinâmica de Sistemas e neles podem ser implementados os mais variados modelos. Utilizando o software Vensim PLE®, modelou-se a digestão anaeróbia do ácido acético por meio de equações baseadas no modelo de cinética enzimática de Monod e no modelo de digestão anaeróbia ADM1. Considerou-se as taxas de consumo de substrato e crescimento de biomassa bacteriana, a inibição causada pelo pH e a quantidade de alcalinizante necessária para atingir o pH desejado deste meio. De forma complementar, integrou-se um modelo de cálculo de alcalinidade do meio e, desta forma, foi possível determinar as concentrações de cada espécie que confere alcalinidade ao meio, considerando o equilíbrio do carbonato. Denominou-se esta modelação (DFC e dinâmica de sistemas) de Modelo Hidro-bioquímico do processamento anaeróbio. Os resultados obtidos por Del Nery et al. (2016) corroboraram com os obtidos nesta tese. / Mathematical models are representations and simplified interpretations of reality or a representation of a system fragment. The modeling of anaerobic processes, such as wastewater treatment in UASB (Upflow Anaerobic Sludge Blanket) reactors, helps managers in the operation of these systems and stability control. The Anaerobic Digestion Model No. 1 (ADM1), created by IWA in 2002, simulates the behavior of anaerobic digestion. However, this model does not consider the system hydrodynamics as a relevant factor in the performance of the process. The effluent flow behavior studies on the reactor inside is possible by hydrodynamic tests. These are conducted through laboratory experiments that uses tracers and this can result in high costs in the conduct of the tests. The Computational Fluid Dynamics (CFD) is an area in fluid mechanics that uses numerical analysis and algorithms to solve and analyze problems related to fluid flow. CFD software can be used to simulate the hydrodynamics assays. It was used in this thesis Ansys® workbench, wherein the CFXTM software was chosen to perform CFD flow simulations. One objective of this thesis was to validate the CFD simulation through laboratory and virtual testing in a UASB bench scale (1.5 liters). In this comparison, it resulted in similar data statistically (Mann-Whitney U test). After validation of the hydrodynamic test, was simulated the same type of assay for an UASB reactor \"Y\" shaped (pilot scale; = 82.27 liters working volume). The test result was N-CSTR (number of complete mixing reactors in series) equal to 4 units, considering a 103.9 liters per day of feed flow (hydraulic retention time of 19 hours). The system dynamics tool makes use of understanding approach of complex models and, through feedback loops and stocks and flows, shows that seemingly simple models can be very complex. There are several system dynamics software and most varied models can be implemented. Using Vensim PLE® software, it was developed an acetate anaerobic digestion model (in this case acetic acid) via equations based on the Monod and ADM1 model. It was considered for the hydro-biochemical modeling, substrate consumption and growth of bacterial biomass rates, the pH inhibition and the amount of alkalizing necessary to achieve the desired pH of the medium. Complementarily, integrated into a calculation alkalinity model of the medium and thus it was possible to determine the concentrations of each species imparts environment alkalinity, considering the carbonate balance.

Software industry is getting very competitive in the wake of recession. In most cases, an organization that quotes a lower price and promises to deliver the product at the earliest walks away with the project. But the factor of quality of the product delivered is also very important because that in turn determines the reputation of an organization, which also plays an important role in getting the next project. Interactions in a software development are dynamic in nature and involve human factors. Models are built taking into account all possible factors so as to present a realistic picture of the development process. System dynamics methodology is used to build these models in Vensim. Three models have been proposed to help manager estimate an approximate time and cost of the project, monitor the project once the timeline is set and monitor the project development to change various factors as the development process goes through various phases of development and testing.

This thesis investigates the important potential of Cooperative Intelligent Transport Systems (C-ITS) onmobility and society. C-ITS appears as a promising solution to reinvent transportation and become avital part of the ever-evolving environment as developments in technology continue to change the world.The goal of this study is to investigate how C-ITS can enhance and promote various forms of mobility.It additionally investigates at how C-ITS applications and policy objectives interact, highlighting C-ITS’contribution to the development of a sustainable society.A thorough examination of the current literature, case studies, and pertinent policies was conductedin order to analyse the possible advantages and difficulties related to C-ITS in detail. In order toprovide seamless communication and interaction between C-ITS systems and other devices, the researchemphasizes the importance of early integration and adoption of C-ITS as a solution. It also emphasizesthe need for standardization, interoperability, and collaborative efforts among stakeholders.Findings demonstrate that C-ITS has the capacity to support policies aimed at improving transportationsystems and mobility in the cities. C-ITS usage has enormous potential for influencing society andmobility. C-ITS reduces accidents while enhancing road safety through real-time communication. Byenhancing traffic flow and promoting alternative modes of transportation, it supports environmentalsustainability. It also has secondary effects such as reducing pollutants and improving air andnoise quality. Through the integration of numerous mobility choices and the provision of real-timeinformation, C-ITS improves accessibility. For implementation to be successful, privacy and securityissues as well as economic reasons must be taken into consideration. To solve the issues posed byconcerns about data privacy, security, and economic factors, however, strong policies, legislation,and safe data processing techniques are needed. C-ITS has the potential to help create a future oftransportation that is safer, more environmentally friendly, and more effective.In the concluding part, the paper suggests numerous possibilities for C-ITS research going forward.It advises combining policies and guiding documents to offer a clearer strategy for utilizing C-ITSsuccessfully. Additionally, creating more complex mathematical models that include equations can helpus comprehend the importance of the variables better. Iterative procedures integrated into detailedmodels allow for the comparison of many scenarios, addressing the various desires of stakeholders andexperts. Additionally, combining C-ITS with Vehicle-to-Everything (VoT) systems offer a chance toinvestigate the real advantages and make it simpler to make comparisons with other variables. Furtherresearch should be carried out on the likelihood of developing an automated mobility system.

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Title from PDF of title page. / Document formatted into pages; contains 83 pages. / Thesis (M.S.I.E.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: Software industry is getting very competitive in the wake of recession. In most cases, an organization that quotes a lower price and promises to deliver the product at the earliest walks away with the project. But the factor of quality of the product delivered is also very important because that in turn determines the reputation of an organization, which also plays an important role in getting the next project. Interactions in a software development are dynamic in nature and involve human factors. Models are built taking into account all possible factors so as to present a realistic picture of the development process. System dynamics methodology is used to build these models in Vensim. / ABSTRACT: Three models have been proposed to help manager estimate an approximate time and cost of the project, monitor the project once the timeline is set and monitor the project development to change various factors as the development process goes through various phases of development and testing. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Companies realize to stay competitive they have to introduce quality improvement programs. Many companies are challenged today with the sustainability of these quality improvement programs. Generally the understanding of the dynamic behaviour of quality improvement programs is poorly understood with soft issues as factors of the system. System dynamics may solve this problem. This research was focussed on operational management of operations. The organising framework of this research has been qualitative research where the research design was a polar type research design where the case studies focussed on initiatives that were dramatic success or failures, with the expectation that their comparison would help identify those processes that prevent competence enhancing change. A dynamic hypothesis has been constructed from archival data, semi-structured interviews and direct observations, gathered during these case studies. A system dynamics model for quality improvement programs in an automotive environment has been tested and expanded to be applicable for a heavy engineering manufacturing environment. The structure of the system dynamics model has been expanded to include a sustainability feedback loop which also included a management support model. The management support model included soft factors such as management support, management pressure and managerial effectiveness. The complete quality improvement program system dynamics simulation model with sustainability has been tested and validated against a real system data, for a heavy engineering manufacturing environment, gathered during the case studies. The model parameters were determined from a calibration algorithm, by using the Vensim® simulation platform, that fitted the real system behaviour the best. A sensitivity analysis has been done on the model parameters determining the information cues for the management decision policies. From the system dynamics model of the complete quality improvement program, including the sustainability feedback loop, proposed management decision policies have been studied that could lead to sustainable quality improvement programs for a heavy engineering manufacturing environment. From these simulation studies several management policies have been proposed. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Graduate School of Technology Management / Unrestricted

Construction of municipal utility complexes has to support continuing population growth, economic development, and a widespread of social interest in environmental preservation. Municipalities face challenges in designing, constructing, and operating environmentally sustainable utility complexes, and their primary goal in developing such a complex is to minimize the environmental impact resulting from energy production and waste treatment (both liquid and solid), management, and disposal. However, decision and policy makers lack a system of systems approach that takes into account multiple interdependent systems comprised of the functional system (infrastructure, facilities, operations within the complex…), the economic system, the social/cultural system, and the environmental system (environmental impact on air, water, soil…). This research proposes a decision support system (DSS) with a new methodology using Vensim software and system dynamics methodology to assess the sustainability of a municipal utility complex system. This DSS incorporates 1) multiple interdependent systems, 2) multiple sustainability/performance indices, and 3) composite sustainability index. Engineers, managers, and researchers should benefit from a system of systems perspective, and from the application of a sustainability assessment method that is developed to provide an environmentally-conscious design, construction and management. Although a municipal utility complex is built with synergistic opportunities for integration of processes of a wastewater treatment plant, a resource recovery facility (aka waste-to-energy (WTE) or incineration facility), a material recycling facility (MRF), and a landfill; engineers tend to use the traditional sustainability assessment methods only to assess the life cycle (LCA) of each system's process over time. They might not necessarily incorporate an assessment based on system dynamics of the functional, economic, environmental, and social/cultural systems. Data from a case study is utilized in this dissertation based on the municipal utility complex in Pasco County in the western region of the State of Florida, USA.