• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.167-172
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• 2010

CANDU spent fuel is to be disposed of at repository finally rather than recycled because of its low fissile nuclide concentration. But the difficult situation of finding a repository site can not help introducing a interim storage in the short term. It is required to find an optimum timing of geological disposal of CANDU spent fuels related to the interim storage operation period. The major factors for determining the disposal starting time are considered as safety, economics, and public acceptance. Safety factor is compared in terms of the decay heat and non-proliferation. Economics factor is compared from the point of the operation cost, and public acceptance factor is reviewed from the point of retrievability and inter-generation ethics. This paper recommended the best solution for the disposal starting time by analyzing the above factors. It is concluded that the optimum timing for the CANDU spent fuel disposal is around 2041 and that the sooner disposal time, the better from the point of technical and safety aspects.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.824-829
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• 2011

The mold is widely used for mass production in present industry. Also, product cycle time is faster, for this request, high productivity improvement in mold machining is required. And, In case of mold manufacturing company, the delivery shortening is required to quickly manufacture new product. Therefore, we aim for the delivery shortening though the method of machining time shortening in mold machining. On this paper, first, we made the NC-code of Insert die-casting as the object model using PowerMill. And then, analyzed cutting force by Toolpath in Insert mold machining using Production Module of Advantedge which is cutting force analysis program. After that, we came up with the optimum conditions of productivity improvement throughout the analysis result of before and after optimization of cutting force, machining time variation, and surface roughness by changing min tangential force to 80, 85, 90% of max tangential force.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.186-195
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• 2005

This paper deals with attitude control design for a thruster system which is mainly used as a control system of space vehicles. Attitude controllers are designed based on a simple blowing-down thruster system structure. In order to consider severe time-delay effects of the thruster system during controller design, the control design problem is defined based on the corresponding limit cycle analysis. Optimal roll controllers and optimal pitch/yaw controllers are resulted from co-evolutionary optimum design processes for each flight phase. The control performances are verified by computer simulations.

• Transactions of the Korean hydrogen and new energy society
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• v.4 no.1
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• pp.21-30
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• 1993

The operational characteristics of a metal hydride heat pump system are strongly dependent on the amound of hydrogen gas transferred by hydriding and dehydriding reactions between the reactors under dynamic conditions. A new metal hydride heat pump combined with hydrogen compressor was constructed and the dependency of its operating conditions on such as cycle time, amount of hydrogen to be transferred between two reacting metal hydride reactors, operating temperature, and heat transmission characteristics of the reactors was investigated to find the optimum operating efficiency. These conditions were also evaluated in connection with the cooling output and hydrogen compressor connected to the system in order to enhance the total efficiency.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.635-641
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• 2005

This paper presents an ASF (Aluminum Space Frame) BIW (Body in White) optimal design, which minimizes weight and satisfies multidisciplinary constraints such as static stiffness, vibration characteristics, low-/high-speed crash, and occupant safety. As only one cycle CPU time for all the analyses is 12 hours, the ASF design having 11-design variable is a large scaled problem. In this study, ISCD-II and conservative least square fitting method were used for efficient RSM modeling. Likewise, the ALM method was used to solve the approximate optimization problem. The approximate optimum was sequentially added to remodel the RSM. The proposed optimization method uses only 20 analyses to solve the 11-design variable problem. Moreover, the optimal design can achieve $15.6\%$ weight reduction while satisfying all the multidisciplinary design constraints.

• Korean Journal of Computational Design and Engineering
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• v.17 no.1
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• pp.1-6
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• 2012

The End Coupling is main component of the aluminum hot roll process. The End Coupling is used for transmission of rotational power with heavy-duty load. Fracture of the End Coupling cause serious economic losses because an End Coupling is a very expensive component and it takes a long time to repair it. Therefore, preventing the destruction of the End Coupling is essential for ensuring a long mechanical life cycle. In this paper, the parametric study on the End Coupling was performed in order to minimize maximum stress under operation loads. To verify the interference of spindle assembly with modified End Coupling, kinematics simulation was performed by applying the various combination type and dynamic boundary condition of the spindle assembly. The interference of optimized model was not occurred during combination process and driving process. As a result of an optimum design for life extension on End Coupling, the maximum stress of modified End Coupling was lower than that of the initial model by 26%.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.33-36
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• 2001

A free piston and free displacer(FPFD) Stirling cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM(Korea Institute of Machinery & Materials). The FPFD Stirling cryocooler employs 1) the Stirling cycle for refrigeration, 2) linear motors for driving the cryocooler, 3) spring and gas support systems, and 4) fine gap for clearance seals. It is the most suitable design for a mechanical cryocooler utilized in night vision environment. The experimental results show KIMM-E1 Stirling cryocooler (with expander manufactured by KIMM) has the higher cooling power and faster response time at optimum charging pressure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1267-1273
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• 2009

Hot press forming can produce high-strength components by rapidly cooling between closed punch and die after hot forming using quenchable boron steel austenized in a furnace. In the hot press forming process, the cooling rate is influenced by the size, position and arrangement of the cooling channel and the file condition of cooling water in the die. Also, mechanical properties of the final components and operation time are related to cooling rate. Therefore, the design of optimized cooling channel is one of the most important works. In this paper, the effect of position and size of the cooling channel on the cooling rate was investigated by using design of experiment and FE analysis in hot press bending process. Therefore the optimum cooling channel ratio was presented in the HPB.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.849-855
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• 2005

Railway fields are complicatedly connected with engineering such as physics, civil engineering, architecture engineering, electrical engineering (Telecommunication, signal, catenary, system), machine engineering and performance phase of project in domestic railway can be divided with four steps : planning, design, supervision, construction. Value Engineering is needed to reduce the cost of long period construction duration and periodically maintenance. Currently, railway design is difficult to act optimum design due to limited time, short of manpower, downsized of design company. therefore, VE concept in Design must require In order to solve this problem. it is called Design Management. This paper presents both item of design management and total design management tool of practical aspects, and describes LCC (Life Cycle Cost) analyze process and accomplishment process for applying VE concept

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.577-578
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• 2006

In this paper, the rubber behavior was calculated for obtaining the optimal process condition which is for producing a transformer with a given performance. This study was carried out using the computer simulation of injection mold filling and packing simulations. In order to remove the crack of product, proper locations of the runner and cooling system configurations could be determined. Based on these results, the transformer is developed by injection molding and guidelines of part design, mold design and processing conditions are established. Finally, the cast savings, cycle time reduce and improvement of productivity will be obtained.