• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.392-398
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• 2005

This paper presents technologies that have strategic importance in future motor drives. The underlying strategic issue for motor drives is maintaining cost while increasing certain dimensions of functionality. The dimensions of functionality which should increase include reliability and added value features such as providing continuous energy optimization, providing sensing of the driven system suitable for application specific diagnostic purposes, and providing continuously optimal thermal utilization of the capability of the drive. This paper will address each of these issues and discuss the technology status for each case, with a focus on research needed to fully deliver the needed functionality.

• 대한기계학회논문집A
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• 제27권4호
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• pp.499-506
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• 2003

The design cycle associated with large engineering systems requires an initial decomposition of the complex system into design processes which are coupled through the transference of output data. Some of these design processes may be grouped into iterative subcycles. In analyzing or optimizing such a coupled system, it is essential to determine the best order of the processes within these subcycles to reduce design cycle time and cost. This is accomplished by decomposing large multidisciplinary problems into several sub design structure matrices (DSMs) and processing them in parallel This paper proposes a new method for parallel decomposition of multidisciplinary problems to improve design efficiency by using the multi-objective genetic algorithm and two sample test cases are presented to show the effect of the suggested decomposition method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.162-163
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• 2016

This paper presents a mathematical model for optimizing earthwork allocation plan that minimizes earthwork cost. The model takes into account operational constraints in the real-world earthwork such as material-type (i.e., quality level of material) and quantities excavated from cut-sections, required quality of material and quantities for each embankment layer, top-down cutting and bottom-up filling constraints, and allocation orders. These constraints are successfully handled by assuming the rock-earth material as the three dimensional (3D) blocks. The study is of value to project scheduler because the model identifies the optimal earth allocation plan (i.e., haul direction (cut and fill pairs), quantities of soil, type of material, and order of allocations) expeditiously and is developed as an automated system for usability. It is also relevant to estimator in that it computes more realistic earthworks costs estimation. The economic impact and validity of the mathematical model was confirmed by performing test cases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2096-2098
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• 2002

In this paper, the optimal evasive maneuver strategies for typical subsonic ASM(anti-ship missile) to reach its target ship with high survivability against CIWS(close in weapon system) are studied. The optimal evasive maneuver input is defined by the homing command optimizing the cost function which takes aiming errors of CIWS into account. The optimization problem for the effective evasive maneuver is formulated based on a simple missile dynamics model and a CIWS model. By means of solving the problem, a multiple hypotheses testing method is proposed. Since this method requires generation of too many hypotheses, the hypothesis-pruning technique is adopted. The solution shows that the optimal evasive maneuver is a bang-bane shaped command whose frequency is varied by the aimpoint determination strategy in CIWS.

• 대한안전경영과학회지
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• 제6권4호
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• pp.215-226
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• 2004

This study develops a improved gate assignment algorithm and decision support system using its algorithm to extract a assignment result minimizing a walking distance of passengers in airport and maximizing the utilization rate of avaliable gates in domestic airports. By operation support system, it may contribute greatly in efficient enlargement of airport operation and increase the airport reliability through quickly coping with takeoff and landing delay of flight due to weather change, preservation and repair of gate, etc. Also, passengers who use airport terminal can minimize time and walking distance for departure, arrival, and transit, and it may greatly reduce the additional operation cost for common gates through maximizing the utilization rate for exclusive usage gates for airplanes which use gates.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2010년도 춘계학술대회
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• pp.219-230
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• 2010

Remarkably improvements have occurred recently in the maintenance management of physical assets and productive systems, so that less wastages of energy and resources occur. The technology of maintenance is about finding and applying cost-effective ways of avoiding or overcoming performance deterioration. Maintenance is thus a vital support function in business, especially as increasingly large investments are being required in physical assets. TPM(Total Productive Maintenance) focuses on optimizing planning scheduling. Availability, performance and quality rate are other factors that affect productivity. Especially there are some losses that affect the overall equipment effectiveness(OEE). These losses lead to low values of OEE, which provides an indication of how effective the production precess is. This study explores the ways in which Korean small and medium manufacturing industries can improve OEE.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.263-270
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• 2002

This study proposes a multi-objective optimum design method for a rational optimization of high-speed railway bridges. This multi-objective optimization is found to be effective in optimizing multi-objective problems that incorporate cost and dynamic responses such as vertical acceleration and displacement. These design factors are so important in the high-speed railway bridges. And the trade off method which is one of the most typical multi-objective optimization methods is used in this study, since the dynamic factors are formulated as objective function and also considered as constraints. And the Pareto curve can be obtained by performing the multi-objective optimization for real high-speed railway bridges. Thus, it is found that more reasonable design can be obtained when compared with those using conventional design procedure.

• 동력기계공학회지
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• 제17권5호
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• pp.86-93
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• 2013

This paper proposes the used of genetic algorithm for optimizing PI controller and describes the dynamic modeling simulation for the permanent magnet synchronous motor driven by simplified vector control with the aid of MATLAB-Simulink environment. Furthermore, three kinds of error criterion minimization, integral absolute error, integral square error, and integral time absolute error, are used as objective function in the genetic algorithm. The modeling procedures and simulation results are described and presented in this paper. Computer simulation results indicate that the genetic algorithm was able to optimize the PI controller and gives good control performance of the system. Moreover, simplified vector control on permanent magnet synchronous motor does not need to regulate the direct axis component current. This makes simplified vector control of the permanent magnet synchronous motor very useful for some special applications that need simple control structure and low cost performance.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.58.1-58.1
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• 2012

Direct write technologies provide flexible and economic means to manufacture low-cost large-area electronics. In this regard inkjet printing has frequently been used for the fabrication of electronic devices. Full advantage of this method, which is capable of reliable direct patterning with line and space dimensions in the 10 to 100 um regime, is only made with all-solution based processing. Among these printable electronic materials, silver and copper nanoparticles have been used as interconnecting materials. Specially, solutions of organic-encapsulated silver and copper nanoparticles may be printed and subsequently annealed to form low-resistance conductor patterns. In this talk, we describe novel processes for forming silver nanoplates and copper ion complex which have unique properties, and discuss the optimization of the printing/annealing processes to demonstrate plastic-compatible low-resistance conductors. By optimizing both the interconnecting materials and the surface treatments of substrate, it is possible to produce particles that anneal at low-temperatures (< $200^{\circ}C$) to form continuous films having low resistivity and appropriate work function for formation of rectifying contacts.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 춘계학술발표 개요집
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• pp.118-122
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• 1995

The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic machinaries as mechanical industry is developed rapidly. The machining precision is asked for manufacturing the valve spools. They could be unstable in the quality by the conventional arc welding and they have a lot of technical problems in manufacturing because their shapes are generally small. By the Precision casting process such as lost wax process, the production cost will be increased. But by the friction welding technique, they will be able to be made without such problems. Furthermore, there is a few study on friction welding of such hydraulic valve spool steels and in-process real-time weld quality evaluation technique by acoustic emission. So that, the final purpose of this study is 1) the development of design and manufacturing technique of hydraulic or pneumatic valve spool by optimizing of friction welding, and 2) the development of in-process real-time weld quality evaluation technique by acoustic emission.