¡@Ever since the foundation in 2000, the branches of Administrative Enforcement Agency have been handling the cases of monetary payment duty in public law with the total amount reaching 3,0178,624, by only about the workforce of 400 people in average while bringing in 1,133,000,000 financial income for the nation in six years. Among these cases, 24,386,174 are closed, which are more effective than in the past and helpful in keeping the publics from evading their duties by luck and therefore realizing the social fairness and justice, thus manifesting the public authority. However, there are still many problems hiding behind the new organizations and their systems, as the number indicates: unresolved cases reach 5,809,904 while 3,732 1,1609,753 dollars are unexecuted. In order to reduce the number of unclosed cases and enhance the administrative efficiency from two indexes: rate of the case-closing and levied tax, the thesis had combined the transaction cost theory from the Coase Theorem with the concept of opportunity cost in law economics, and had discussed the forming causes and strategies from three aspects under the principle of maximum efficiency, while not omitting the point of view of the public choices by the people of the duty. Three main conclusions are therefore made as follow: Firstly, speaking of system in terms of case management and evaluation, the amount of case closed must outnumbers the case received, while different types of cases (according to the amount of money) must be reduced in proportion; moreover, specific execution procedure should be arranged according to its types, and to indicate a clear termination of the time rather than being delayed for too long. Secondly, as far as the case efficiency is concerned, the more payment channel ,the better. In addition, by using information technology, it is effective in exchanging the information among different individuals, and speeding up the case to be closed. Thirdly, in the part of case receiving, be sure to monitor the loading of cases according to the workforce and to adjust the human resource or control the speed of case receiving. Setting up the voucher re-transfer evaluation mechanism to avoid the running-empty of administrative procedure and the waste of resource; to build up the pre-case database and to provide decision support system of the case execution so as to reduce the cost of research and decision making.

In a world with a growing population there is a trend toward higher and higher energy usage. Because of the cost involved in producing extra energy, there is a need for more efficient usage of the energy that is already available. The issue of efficiency rings home especially clear with electric motors. Although induction motors are used in many different applications, the motors used in electric vehicles must be able to generate a large starting torque as well as operate over a wide speed range. This work analyzes the restrictions placed on the motor and inverter drive system. It also looks at the best method for controlling the drive in order to achieve the highest efficiency out of the drive. While other works have shown methods of achieve high efficiency out of the motor, it is the assertion of this work that the efficiency of the total drive is more important. It is to that end that this work analyzes the performance of an induction motor under low torque and speed where a traction drive utilizes the most energy. / Master of Science

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Motor generator sets are widely used to generate electricity in case of grid failure or to supply part of the demand for commercial and industrial consumers. The vast majority of motor generator sets work with constant speed proportional to the grid frequency or to the frequency that is imposed on the load. As a consequence, the motor operates at a speed that does not always correspond to the speed that provides the lowest fuel consumption and/or lower emissions. Aiming to promote degrees of freedom to optimize the performance of motor generator sets, this dissertation describes a control and supervision method for motor generator sets with variable speed where the internal combustion motor is not directly linked to grid frequency. For this, a method of control and supervision for the converters which are inserted between the generator and the grid is developed in details. Finally, simulation and experimental results are presented to demonstrate the performance of the proposed method. / Grupos motores geradores são largamente utilizados para a geração de energia elétrica em caso de falta na rede ou para suprir parte da demanda dos consumidores comerciais e industriais. Na sua grande maioria, grupos motores geradores trabalham com velocidade constante proporcional à frequência da rede ou à frequência que está sendo imposta à carga. Desta forma, o motor opera a uma velocidade que nem sempre corresponde à velocidade que proporciona o menor consumo de combustível e/ou menor emissões de gases poluentes. Visando promover graus de liberdade para otimizar o desempenho de grupos motores geradores, esta dissertação descreve um sistema de controle e supervisão para grupos motores geradores que operam em velocidade variável onde a rotação do motor de combustão interna não está diretamente vinculada com a frequência da rede. Para tanto, propõe-se a utilização e desenvolve-se em detalhes um método de controle e supervisão para os conversores que são inseridos entre o gerador e a rede. Por fim, são apresentados resultados de simulação e experimentais que comprovam o desempenho do método proposto.

The main goal of the work is development of the electric car with fuel cells. The whole complex drive will be optimized with respect of minimal consumption of the energy due to achievement of the maximal range of the car. The first part of the work deals with definition of the parameters of the whole drive in dependence of various operating state of the car. The second part describes some acceptable realizations of the traction drive. The most suitable solution was chosen for realization of the small electric car. The third part deals with principle of the minimization of the losses of the asynchronous machine in the wide range of torque and speed. The last part describes final conception and especially technical realization of the car and its parts.