• 대한기계학회논문집
• /
• 제14권6호
• /
• pp.1464-1473
• /
• 1990

Optimal design parameters are estimated from the sensitivity function and performance index variation. Suspension design modification for performance improvement and basic materials for practical applications are presented. The linear quarter model of a vehicle suspension is analyzed in order to represent the utilities of sensitivity analysis, and sensitivity function is determined in the frequency domain. The change of frequency response function is predicted, which depends on the design parameter variation and the property is verified by computer simulation. As an investigation results of sensitivity function for the vibrational amplitude of sprung mass to road profile input, it is shown that the most sensitive parameters are the suspension damping and the suspension stiffness. In order to identify the effects of these two parameters to the performance of suspension system, the performance index variation according to the changes of parameters is considered and then optimal design parameters are determined. It is verified that the system response is improved noticeably in the both of frequency and time domain after the design modification with the optimal parameters.

• 대한기계학회논문집A
• /
• 제25권2호
• /
• pp.182-191
• /
• 2001

The paper describes the improvement on concurrent subspace optimization(CSSO) via automatic differentiation. CSSO is an efficient strategy to coupled multidisciplinary design optimization(MDO), wherein the original design problem is non-hierarchically decomposed into a set of smaller, more tractable subspaces. Key elements in CSSO are consisted of global sensitivity equation, subspace optimization, optimum sensitivity analysis, and coordination optimization problem that require frequent use of 1st order derivatives to obtain design sensitivity information. The current version of CSSO adopts automatic differentiation scheme to provide a robust sensitivity solution. Automatic differentiation has numerical effectiveness over finite difference schemes tat require the perturbed finite step size in design variable. ADIFOR(Automatic Differentiation In FORtran) is employed to evaluate sensitivities in the present work. The use of exact function derivatives facilitates to enhance the numerical accuracy during the iterative design process. The paper discusses how much the automatic differentiation based approach contributes design performance, compared with traditional all-in-one(non-decomposed) and finite difference based approaches.

• Journal of Power Electronics
• /
• 제11권1호
• /
• pp.105-111
• /
• 2011

By having accurate knowledge of the magnetic field distribution and the thrust calculation in linear synchronous motors, assessing the performance and optimization of the motor design are possible. In this paper, after carrying out a performance analysis of a single-sided wound secondary linear synchronous motor by varying the motor design parameters in a layer model and a d-q model, machine single- and multi-objective design optimizations are carried out to improve the thrust density of the motor based on the motor weight and the motor efficiency multiplied by its power factor by defining various objective functions including a flexible objective function. A genetic algorithm is employed to search for the optimal design. The results confirm that an overall improvement in the thrust mean, efficiency multiplied by the power factor, and thrust to the motor weight ratio are obtained. Several design conclusions are drawn from the motor analysis and the design optimization. Finally, a finite element analysis is employed to evaluate the effectiveness of the employed machine models and the proposed optimization method.

• Journal of Magnetics
• /
• 제16권4호
• /
• pp.374-378
• /
• 2011

Axial Field Permanent Magnet (AFPM) generators are widely applied for the small wind turbine because of the higher power density per unit weight than that of the conventional radial field generator. It is caused by the disc shaped rotor and the stator structures. The generally used AFPM generator, AFER-NS generator, is composed of the two side's external rotors and non-slotted stator without stator core. However, the output voltage and the output power are limited by the large reluctance by the long air-gap flux paths. In this paper, the design study of AFIR-S generator having double side's slotted stator core is accomplished to improve the output generation characteristics. The electromagnetic design analysis and the design improvement of the suggested AFIR-S generator are studied. Firstly, the electromagnetic design analysis was done to increase the power density. Secondly, the design optimizations of the rotor pole-arc ratio of permanent magnet are accomplished to increase the output power and to reduce the cogging torque. Finally, the output performances of AFER-NS and AFIR-S generator are compared with each other. For this study, 3D FEA is applied for the design analysis because of three dimensional electromagnetic structures.

• 도시과학
• /
• 제11권1호
• /
• pp.37-47
• /
• 2022

Even if Korea has established various legal guidelines as well as plans for the purpose of systematic management of urban citycapes, various problems have been pointed out, such as a decrease in operational efficiency because the legal framework is not clearly defined and the guidelines do not fully reflect regional characteristics. In the midst of this, Singapore is being mentioned as a representative example of enhancing international competitiveness by forming an outstanding urban cityscape through successful urban planning and operating system. Therefore, this study aims to suggest a direction for the improvement of Korea's urban planning and design guidelines by investigating and analyzing the characteristics of Singapore's urban planning system and design guidelines. As a result of the research and analysis, it was concluded that Singapore's urban planning system was based on the unified planning and management system. In particular, the Singapore Urban Design Guidelines provide differentiated guidelines to maintain and strengthen regional characteristics based on linkage with higher-level plans as detailed practical guidelines, and were operated as flexible guidelines reflecting the changes of the times and the needs of members of society. It also provides a direction for the improvement of the Korean urban design system, such as to increase the executionablity of the plan and the efficiency of operation by utilizing various guidance and support policies, rational and simplified deliberation procedures, and allow a platform that enhances the accessibility and convenience of related information.

• 수산해양기술연구
• /
• 제26권4호
• /
• pp.341-352
• /
• 1990

The purpose of this research is to develop the design/control method that can be used for the improvement of harbour tranquility and water quality of fishing ports. For this end, firstly, the hydraulic environmental characteristics of fishing ports in the coastal waters of the Korean Peninsula are analysed and discussed combined with disasters of facilities and vessels in the ports. Secondly the problems of water quality control is pointed out considered with the improvement measures of harbour tranquility such as the methods of lengthen of main breakwaters and construction of wave absorbing structures. Finally, the control characteristics of composite functions of water quality and tranquility of fishing port are discussed and the improved control method si proposed using the experimental results for the various measures. The proposed measure is proved to be a applicable method to improve these two main functions on the design of fishing port.

• 품질경영학회지
• /
• 제24권1호
• /
• pp.96-109
• /
• 1996

In this paper, we consider the quality problem of black oxide process in casting for which Taguchi method is used. We explain simply the Taguchi method and existing problems in Black Oxide process. We analyze the problem by the quality improvement procedure proposed by Taguchi. The design factors and noises using cause-effect diagram are found, the experiment is made using orthogonal array. After ANOVA, the critical factors are determined and the optimal process condition is designed. After parameter design, we derive the tolerance levels. As a result of changing the levels of process parameters, the variance of quality characteristic was decreased by quarter and the average value was also decreased by half. We estimated the predictable profit of the improvement.

• 농촌계획
• /
• 제5권2호
• /
• pp.38-45
• /
• 1999

The purpose of this study is to investigate the characteristics and suggest the Improvement directions of the facilities in Recreational Forests. This study adopted such various analysis methods as reviewing related documents, surveying the existing sites, and using questionnaire to visitors and managers. The result of this study can be summarized as follows ; 1) The major facilities of Recreational Forests are the lodging, recreation, and sports ones. 2) The primary factor for the visitor's satisfaction is the quality of natural environment, but that for their dissatisfaction is the lack of variety of the available facility. 3) The major problems of facilities in Recreational Forests are their number and design. This study suggests the improvement of accessibility and design of the facilities in the Recreational Forests.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제16권4호
• /
• pp.263-271
• /
• 2016

Purpose: A slurry pump for flue gas desulfurization system performs a role that discharges the slurry of a plaster shape in a thermal power plant. Since a slurry pump transfers the slurry by the centrifugal force, it has the friction wear in the impeller and liner because of the slurry. Methods: In this study, failure analysis and test evaluation on the slurry pump have been proposed and the process that reliability of the product improves through design improvement has been presented. And failure cause of typical failure case has been investigated and improvement design has been presented. Results: Reliability improvement is established by analysis of the test results of before and after acceleration test. Conclusion: This study can be provided to improve the product reliability through failure analysis of a slurry pump.

• 전기학회논문지
• /
• 제65권1호
• /
• pp.58-64
• /
• 2016

In this paper, the design of rotor shape was performed for improvement of start-up characteristics and efficiency in single-phase LSPM. In order to improve the start-up characteristics, shape of rotor aluminium cage bar was changed. Through arrangement of permanent magnets and installation of flux barriers, it was performed torque ripple reduction and efficiency improvement. Cogging torque and back-EMF is calculated by the no-load analysis, start-up time is calculated by the start-up state analysis, efficiency and torque ripple is calculated by steady state analysis. The characteristics of the motor were calculated through FEM.