Low Impact Development (LID) is gaining popularity as a solution to erosion, flooding, and water quality problems that stormwater ponds partially address. LID analysis takes a spatially lumped approach, based on maintaining the predevelopment Curve Number and time of concentration, precluding consideration of the spatial distribution of impervious areas and Integrated Management Practices (IMP's), runoff-runon processes, and the effects of land grading. Success is thus dependent on the accuracy of the assumption of watershed uniformity, applied to both land cover distribution and flow path length. Considering the cost of long-term paired watershed monitoring, continuous, spatially-distributed hydrologic modeling was judged a better method to compare the response of LID, forest, and conventional development. Review of available models revealed EPA-SWMM 4.4H as the most applicable to the task. A 4.3-acre subwatershed of a local subdivision was adapted to LID using impervious surface disconnection, forest retention, and IMPs. SWMM was applied to the LID development at a fine spatial scale, yielding an 80-element SWMM model. The LID model was modified to reflect conventional development, with gutters, storm sewer, and detention. A predevelopment forest model was also developed. Two parameter sets were used, representing a range of assumptions characterized as favorable or unfavorable toward a particular development form. Modeled scenarios included favorable and unfavorable versions of Forest, LID, uncontrolled Conventional Development, and Conventional Development with Stormwater Management. SWMM was run in continuous mode using local rainfall data, and event mode using NRCS design storms. Runoff volumes, peak flows, and flow duration curves were compared. / Master of Science

A proposta do trabalho é criar um modelo de simulação híbrida capaz de representar um sistema logístico. Partindo de uma investigação bibliográfica conceitual das metodologias de simulação de eventos discretos e da metodologia de simulação contínua (System Dynamics) capaz de revelar suas características principais e seus potenciais de aplicabilidade, é possível delinear as possibilidades de contribuição de ambas as metodologias para o desenvolvimento de modelos híbridos (metodologias discreta + contínua) de simulação. O modelo híbrido é desenvolvido sob a plataforma AnyLogic, e a integração adequada de ambas as metodologias no modelo criado é capaz de expandir o espectro de compreensão do sistema, com a possibilidade de integração de aspectos físicos e dimensionais a aspectos políticos e comportamentais do sistema em estudo, apresentando-se como ferramenta poderosa para sobrevivência às exigentes demandas concorrenciais. / This study aims at creating a hybrid simulation model able to properly represent a logistics system. Departing from a conceptual literature review about the discrete-event and the continuous (System Dynamics) simulation methodologies able to reveals its main features and potential of applicability, it is possible to define the possibilities of developing hybrid (discrete + continuous) simulation models. The proper integration of both methodologies in a hybrid model allows the expansion of the comprehension spectrum of the system, with the possibility of integrating the physical and dimensional aspects to political and behavior patterns, revealing the hybrid methodology as a powerful tool to succeed in the highly demanding business world.

A proposta do trabalho é criar um modelo de simulação híbrida capaz de representar um sistema logístico. Partindo de uma investigação bibliográfica conceitual das metodologias de simulação de eventos discretos e da metodologia de simulação contínua (System Dynamics) capaz de revelar suas características principais e seus potenciais de aplicabilidade, é possível delinear as possibilidades de contribuição de ambas as metodologias para o desenvolvimento de modelos híbridos (metodologias discreta + contínua) de simulação. O modelo híbrido é desenvolvido sob a plataforma AnyLogic, e a integração adequada de ambas as metodologias no modelo criado é capaz de expandir o espectro de compreensão do sistema, com a possibilidade de integração de aspectos físicos e dimensionais a aspectos políticos e comportamentais do sistema em estudo, apresentando-se como ferramenta poderosa para sobrevivência às exigentes demandas concorrenciais. / This study aims at creating a hybrid simulation model able to properly represent a logistics system. Departing from a conceptual literature review about the discrete-event and the continuous (System Dynamics) simulation methodologies able to reveals its main features and potential of applicability, it is possible to define the possibilities of developing hybrid (discrete + continuous) simulation models. The proper integration of both methodologies in a hybrid model allows the expansion of the comprehension spectrum of the system, with the possibility of integrating the physical and dimensional aspects to political and behavior patterns, revealing the hybrid methodology as a powerful tool to succeed in the highly demanding business world.

A software architecture is one of the first steps towards a software system. A software architecture can be designed in different ways. During the design phase, it is important to select the most suitable design of the architecture, in order to create a good foundation for the system. The selection process is performed by evaluating architecture alternatives against each other. We investigate the use of continuous simulation of a software architecture as a support tool for architecture evaluation. For this purpose, we study a software architecture of an existing software system in an experiment, where we create a model of it using a tool for continuous simulation, and simulate the model. Based on the results from the simulation, we conclude that the system is too complex to be modeled for continuous simulation. Problems we identify are that we need discrete functionality to be able to correctly simulate the system, and that it is very time-consuming to develop a model for evaluation purposes. Thus, we find that continuous simulation is not appropriate for evaluating a software architecture, but that the modeling process is a valuable tool for increasing knowledge and understanding about an architecture.

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<p>VIRTUAL PROTOTYPING has been generally adopted in product development in order to minimise the traditional reliance on testing of physical prototypes. It thus constitutes a major step towards solving the conflict of actual increasing development cost and time due to increasing customer demands on one side, and the need to decrease development cost and time due to increasing competition on the other. Particularly challenging for the off-road equipment industry is that its products, working machines, are complex in architecture. Tightly coupled, non-linear sub-systems of different technical domains make prediction and optimisation of the complete system’s dynamic behaviour difficult.</p><p>Furthermore, in working machines the human operator is essential for the performance of the total system. Properties such as productivity, fuel efficiency, and operability are all not only dependent on inherent machine properties and working place conditions, but also on how the operator uses the machine. This is an aspect that is traditionally neglected in dynamic simulations, because the modelling needs to be extended beyond the technical system.</p><p>The research presented in this thesis focuses on wheel loaders, which are representative for working machines. The technical system and the influence of the human operator is analysed, and so-called short loading cycles are described in depth. Two approaches to rule-based simulation models of a wheel loader operator are presented and used in simulations. Both operator models control the machine model by means of engine throttle, lift and tilt lever, steering wheel, and brake only – just as a human operator does. Also, only signals that a human operator can sense are used in the models. It is demonstrated that both operator models are able to adapt to basic variations in workplace setup and machine capability. Thus, a “human element” can be introduced into dynamic simulation of working machines, giving more relevant answers with respect to operator-influenced complete-machine properties such as productivity, fuel efficiency, and operability already in the concept phase of the product development process.</p> / ISRN/Report code: LiU-Tek-Lic 2005:44

No description available.

VIRTUAL PROTOTYPING has been generally adopted in product development in order to minimise the traditional reliance on testing of physical prototypes. It thus constitutes a major step towards solving the conflict of actual increasing development cost and time due to increasing customer demands on one side, and the need to decrease development cost and time due to increasing competition on the other. Particularly challenging for the off-road equipment industry is that its products, working machines, are complex in architecture. Tightly coupled, non-linear sub-systems of different technical domains make prediction and optimisation of the complete system’s dynamic behaviour difficult. Furthermore, in working machines the human operator is essential for the performance of the total system. Properties such as productivity, fuel efficiency, and operability are all not only dependent on inherent machine properties and working place conditions, but also on how the operator uses the machine. This is an aspect that is traditionally neglected in dynamic simulations, because the modelling needs to be extended beyond the technical system. The research presented in this thesis focuses on wheel loaders, which are representative for working machines. The technical system and the influence of the human operator is analysed, and so-called short loading cycles are described in depth. Two approaches to rule-based simulation models of a wheel loader operator are presented and used in simulations. Both operator models control the machine model by means of engine throttle, lift and tilt lever, steering wheel, and brake only – just as a human operator does. Also, only signals that a human operator can sense are used in the models. It is demonstrated that both operator models are able to adapt to basic variations in workplace setup and machine capability. Thus, a “human element” can be introduced into dynamic simulation of working machines, giving more relevant answers with respect to operator-influenced complete-machine properties such as productivity, fuel efficiency, and operability already in the concept phase of the product development process. / <p>ISRN/Report code: LiU-Tek-Lic 2005:44</p>

The thesis deals with artificial neural networks theory. Subsequently, fuzzy sets are being described and fuzzy logic is explained. The hybrid neuro-fuzzy system stemming from ANFIS system is designed on the basis of artificial neural networks, fuzzy sets and fuzzy logic. The upper-mentioned systems' functionality has been demonstrated on an inverted pendulum controlling problem. The three controllers have been designed for the controlling needs - the first one is on the basis of artificial neural networks, the second is a fuzzy one, and the third is based on ANFIS system.  The thesis is aimed at comparing the described systems, which the controllers have been designed on the basis of, and evaluating the hybrid neuro-fuzzy system ANFIS contribution in comparison with particular theory solutions. Finally, some experiments with the systems are demonstrated and findings are assessed.