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Human operators often employ discontinuous or "bang-bang" control strategies when performing large-amplitude acquisition tasks. The current study applies Variable Structure Control (VSC) techniques to model human operator behavior during acquisition tasks. The result is a coupled, multi-input model replicating the discontinuous control strategy. In the VSC formulation, a switching surface is the mathematical representation of the operator's control strategy. The performance of the Variable Strategy Model (VSM) is evaluated by considering several examples, including the longitudinal control of an aircraft during the visual landing task. The aircraft landing task becomes an acquisition maneuver whenever large initial offsets occur. Several different strategies are explored in the VSM formulation for the aircraft landing task. First, a switching surface is constructed from literal interpretations of pilot training literature. This approach yields a mathematical representation of how a pilot is trained to fly a generic aircraft. This switching surface is shown to bound the trajectory response of a group of pilots performing an offset landing task in an aircraft simulator study. Next, front-side and back-side landing strategies are compared. A back-side landing strategy is found to be capable of landing an aircraft flying on either the front side or back side of the power curve. However, the front-side landing strategy is found to be insufficient for landing an aircraft flying on the back side. Finally, a more refined landing strategy is developed that takes into the account the specific aircraft's dynamic characteristics. The refined strategy is translated back into terminology similar to the existing pilot training literature. / Ph. D.

Human operator models developed using optimal control theory are typically complicated and over-parameterized, even for simple controlled elements. Methods for generating less complicated operator models that preserve the most important characteristics of the full order model are developed so that the essential features of the operator dynamics are easier to determine. A new formulation of the Optimal Control Model (OCM) of the human operator is developed that allows order reduction techniques to be applied in a meaningful way. This formulation preserves the critical neuromotor dynamics and time delay characteristics of the human operator. The Optimal Projection (OP) synthesis technique is applied to a modified version of the OCM. Using OP synthesis allows one to determine operator models that minimize the quadratic performance index of the OCM with a constraint on model order. This technique allows analysts to formulate operator models of fixed order. Operator model reduction methods based on variations of balanced realization techniques are also developed since they reduce the computational complexity associated with OP synthesis yet maintain a reasonable level of accuracy. Computer algorithms are developed that insure that the reduced order models have noise to signal ratios that are consistent with OCM theory. The OP method generates operator models of fixed order that are consistent with OCM theory in all respects, i.e. optimality, neuromotor lag, time delay, and noise to signal ratios are all preserved. The other model reduction techniques preserve these features with the exception of optimality. Each technique is applied to a variety of controlled elements to illustrate how performance and frequency response fidelity degrade when the order of the operator model is reduced. / Ph. D.

<p>This thesis is about the design and evaluation of a graphical display that aims at showing the behavior of a complex automated system in action. A problem with complex automation is that it sometimes surprises the user by performing actions that were not expected. The reason of this is poor communication of system activities. In order to study how to design for anticipative automation communication a prototype around automatic vehicle driving on highways was designed and evaluated. The design work focused on designing a display that contained anticipation as a use quality. This resulted in a display design that aimed at representing the working scene in such a way that the user would be able to recognize and compare the system view with the real situation. In order to accomplish this, three layers of information were merged together in the display, these layers were; the automaton’s image of how the world is seen, the way that image is perceived and interpreted in terms of system action necessity and out of that the actions that the system plans to perform in the near future. The evaluation of the design prototype showed that it was possible to anticipate system actions but that the information detail level was insufficient for the evaluators to completely trust system decisions. The evaluation also showed that trust can be created by letting the automaton represent the perception of the situation in such a way that the user is able to compare it to personal experience from performing the task manually. Anticipation can be created through showing what future the automaton is expecting and what actions that needs to be performed in order to reach or maintain the general system task or goal.</p>

This thesis is about the design and evaluation of a graphical display that aims at showing the behavior of a complex automated system in action. A problem with complex automation is that it sometimes surprises the user by performing actions that were not expected. The reason of this is poor communication of system activities. In order to study how to design for anticipative automation communication a prototype around automatic vehicle driving on highways was designed and evaluated. The design work focused on designing a display that contained anticipation as a use quality. This resulted in a display design that aimed at representing the working scene in such a way that the user would be able to recognize and compare the system view with the real situation. In order to accomplish this, three layers of information were merged together in the display, these layers were; the automaton’s image of how the world is seen, the way that image is perceived and interpreted in terms of system action necessity and out of that the actions that the system plans to perform in the near future. The evaluation of the design prototype showed that it was possible to anticipate system actions but that the information detail level was insufficient for the evaluators to completely trust system decisions. The evaluation also showed that trust can be created by letting the automaton represent the perception of the situation in such a way that the user is able to compare it to personal experience from performing the task manually. Anticipation can be created through showing what future the automaton is expecting and what actions that needs to be performed in order to reach or maintain the general system task or goal.

<p>The purpose of this thesis is to explore how support systems enable human control within normal flight operations. The thesis focuses on the use of memory supports during flight, such as a handheld computing device, memory strategies and checklists. The support systems are studied from the theoretical perspective of Human Factors. In particular, decision making theories have contributed to the thesis. From previous research it is found that feedback to the operator in case of a human error is essential to keep him or her in a safe sequence of decisions and actions.</p><p>To facilitate the pilots’ tasks in cockpit, computing devices are out on the market. Several of the technical aids are computers installed in cockpit whereas others are smaller, portable devices with hardware not specifically designed for use in cockpit. Jump-seat observations have been performed at an airline company to explore the pilots’ work process in cockpit where a handheld computing device, with hardware not specifically designed for cockpit, is in use. Subsequent semi-structured interviews were conducted to receive the pilots’ experiences of findings from the observations and to receive descriptions of decisions and support systems.</p><p>The thesis includes a description of flight operations from a pilot perspective. The main focus is on operations in the preflight phase where the new computing device is used. Identified characteristics in flight operations are factors such as cooperation, communication, interruptions. Furthermore, identified factors in the decision making were such as routine, environmental constraints, discrete alternatives and dependency between decisions. Feedback points during the sequence of tasks performed with the handheld computing device were distinguished. These points are moments when feedback is possible. For example, when the pilots cross-check tasks they receive feedback from each other. It was found that the pilots did not use every opportunity to receive feedback on their performance. The reason of the non-used feedback point was that it was not required by the Standard Operating Procedures or by any functions or design of the device. Within flight operations in general, it was found that the most important techniques to detect a human error such as a memory lapse were by pilots’ earlier experiences, the use of checklists and by receiving feedback from the other pilot.</p>

Made available in DSpace on 2014-10-09T12:51:59Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:58Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:51:59Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:58Z (GMT). No. of bitstreams: 0 / Este trabalho apresenta o desenvolvimento de um Simulador do Reator de Pesquisa IEAR1. O Simulador foi desenvolvido com Visual C++ em duas etapas: 1) construção dos modelos matemáticos e 2) criação e configuração de interfaces gráficas em um aplicativo Windows XP. Utilizou-se uma modelagem simplificada dos principais fenômenos físicos: o nuclear através de cinética pontual, e o modelo de térmica e hidráulica através das leis de conservação de massa e energia no canal médio do reator. As equações diferenciais dinâmicas dos processos nucleares, térmicos e hidráulicos foram solucionadas pela técnica de diferenças finitas através do método de Runge-Kutta de 4ª ordem. Foram modelados os sistemas: controle de reatividade, resfriamento do reator e proteção do reator. As variáveis de processo são armazenadas em arquivos ASCII. O Simulador permite o usuário navegar por interfaces gráficas dos sistemas e monitorar tendências dos transientes de operação sendo uma ferramenta interativa para ensino e treinamento de operadores do IEA-R1. Este também pode ser usado por alunos e professores no ensino de teoria de reatores, térmica e hidráulica. O Simulador permite simulações de operações de partida, manobra de potência e parada. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

The purpose of this thesis is to explore how support systems enable human control within normal flight operations. The thesis focuses on the use of memory supports during flight, such as a handheld computing device, memory strategies and checklists. The support systems are studied from the theoretical perspective of Human Factors. In particular, decision making theories have contributed to the thesis. From previous research it is found that feedback to the operator in case of a human error is essential to keep him or her in a safe sequence of decisions and actions. To facilitate the pilots’ tasks in cockpit, computing devices are out on the market. Several of the technical aids are computers installed in cockpit whereas others are smaller, portable devices with hardware not specifically designed for use in cockpit. Jump-seat observations have been performed at an airline company to explore the pilots’ work process in cockpit where a handheld computing device, with hardware not specifically designed for cockpit, is in use. Subsequent semi-structured interviews were conducted to receive the pilots’ experiences of findings from the observations and to receive descriptions of decisions and support systems. The thesis includes a description of flight operations from a pilot perspective. The main focus is on operations in the preflight phase where the new computing device is used. Identified characteristics in flight operations are factors such as cooperation, communication, interruptions. Furthermore, identified factors in the decision making were such as routine, environmental constraints, discrete alternatives and dependency between decisions. Feedback points during the sequence of tasks performed with the handheld computing device were distinguished. These points are moments when feedback is possible. For example, when the pilots cross-check tasks they receive feedback from each other. It was found that the pilots did not use every opportunity to receive feedback on their performance. The reason of the non-used feedback point was that it was not required by the Standard Operating Procedures or by any functions or design of the device. Within flight operations in general, it was found that the most important techniques to detect a human error such as a memory lapse were by pilots’ earlier experiences, the use of checklists and by receiving feedback from the other pilot. / QC 20101109

The appearance of the electrical appliances has undergone a dramatic change in many aspects since the 1920&rsquo / s. Throughout years, along with their changed appearance, the way the appliances are perceived has altered. The interface of domestic products is mainly dominated by visual elements. Undoubtedly, the domination of the visual perception in the interfaces of the appliances might cause complications in the interaction between the product and visually impaired users. In this thesis, the interaction between the electrical household appliances and visually impaired user is examined to identify the strong points in the interaction as well as any complications that may occur during the interaction. Observations were conducted with ten users to explore the interaction between the visually impaired users and three electrical domestic appliances: washing machine, vacuum cleaner and iron. The findings of the observations indicate that visually impaired users can operate their appliances, with some limitations. Yet a number of common problematic points related to the interface elements, which hinder from using their electrical appliances with full functionality, were encountered. At the end of the study, a list of design recommendations, some of which offered in the literature previously, are suggested.