• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.32-42
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• 1999

Approximate lofting or skinning is one of practical surface modeling techniques well used in CAD and reverse engineering applications. Presented in this paper is a method for approximately lofting a given set of curves wihin a specified tolereance. It is based on refitting input curves simultaneously on a common knot vector and interpolating them to get a resultant NURBS surface. A concept of reducing the number of interior knots of the common knot vector is well adopted to acquire more compact representation for the resultant surface. Energy minimization is newly introduced in curve refitting process to stabilize the solution of the fitting problem and get more fair curve. The proposed approximate lofting provides more smooth surface models and realizes more efficient data reduction expecially when the parameterization and compatibility of input curves are not good enough. The method has been successfully implemented in a new CAD/CAM product VX Vision? of Varimetrix Corporation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.771-772
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• 2014

In this paper, the integrated design method of suction muffler in compressor was studied. There are three things to consider when designing this. First, the transmission loss was maximized to consider the noise reduction. Second, dissipation energy of fluid flow was minimized for energy efficiency. Finally, acoustical resonance frequency of suction muffler was controlled because energy efficiency can be increased by supercharging of refrigerant. Therefore, suction muffler was designed to have the specific resonance frequency. The input impedance was used for designing target acoustical resonance frequency. Topology optimization was used for optimization method.

• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.49-63
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• 2017

Solar cells have widely been utilized for a satellite to convert sunlight energy into electricity in space. Many different types of solar cells appropriate for each satellite program are available in current markets, which enables us to construct a solar array light and small often required from a low Earth orbit (LEO) synthetic aperture radar (SAR) satellite. Thus, it is important to choose a proper solar cell satisfying the requirements of mass and size for the solar array. In this article, we have surveyed typical suppliers and have discussed some characteristics of solar cells. Conceptual design examples of the solar array for LEO SAR satellites using several types of solar cells have been performed to show the pros and cons of solar cells by comparison of the total mass and size necessary for the solar array.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.207-212
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• 2012

It is important to produce the high-temperature and high-pressure air for the concentrated solar power system using the combined cycle. In this paper, we designed two types of tubular receivers to heat up the compressed air and provided their preliminary experimental results for performance evaluation and further improvements. The developed receivers are in a square cavity shape surrounded by flow conduits for easy scale-up and radiation loss reduction. The two receivers were tested with 5 bar air in the KIER solar furnace and evaluated in terms of the outlet temperature and the efficiency.

• Solar Energy
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• v.13 no.2_3
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• pp.5-11
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• 1993

The study, considering the fact that most of the recently built atrium buildings do not fulfill their capacity of energy conservation and environmental control, aims to develop design strategies for architects in designing atrium buildings in terms of energy/environment standpoint. The research includes case studies of existing atrium buildings, quantatative analysis of energy performance for atrium buildings and systematic investigation of various aspects of atrium regarding its function of thermal, luminous and acoustical control of a building. The result of the study may contribute to the considerable reduction of energy consumption as well as to improvement of overall building environment.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.101-107
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• 2004

Recently the objective of vehicle design was focused on the crash safety and the energy saving. For the energy saving vehicle structures must be light weight, but for the crash safety some energy absorbing elements must be added. In this paper hybrid structure which consists of a steel and a FRP was studied on the energy absorption characteristics under the impact load by finite element method. Test results of the other researchers were compared with that of computer simulation on this simple hybrid structure. Side rail of vehicle front structure was replaced with hybrid materials for the application of the vehicle structure. 35mph frontal crash simulation was performed with hybrid structure and with conventional steel structure. By the adoption of hybrid structure, the improvement of energy absorption characteristics and reduction of weight was observed under the frontal crash simulation.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.2
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• pp.80-84
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• 2009

Dynamic voltage and frequency scaling (DVFS) is an effective method to achieve low power design. In our work, we present an analytical DVFS method which judiciously exploits correlation information in runtime distribution while satisfying deadline constraints. The proposed method overcomes the previous distribution-aware DVFS method [2] which has pessimistic assumption on which runtime distributions are independent. Experimental results show the correlation-aware DVFS offers 13.3% energy reduction compared to existing distribution-aware DVFS [2].

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.137-142
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• 1999

소형원자로는 크기가 작아서 경제성이 떨어지는 단점이 있지만 안전성이 높아 수출용 원자로로서 가능성이 높다. 소형원자로의 이용 범위는 지역난방용 원자로, 담수화플랜트, 선박 및 잠수함의 추진용 원자로 그리고 우주 탐사용 원자로 등으로 확대되었으며 다양한 형태로 개발되었다. 소형원자로 개발에 있어서 주기길이 연장은 핵연료주기 경제성에 매우 큰 영향을 미친다.(중략)

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.1-7
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• 2015

As energy consumption of building and the reduction of carbon dioxide emissions have been emphasized, phase change materials(PCM) have been introduced as building materials due to its high heat storage performance. Using shape-stabilizing technique, octadecane/xGnP shape-stabilized PCM(SSPCM) can prevent leakage and improve heat storage performance. The objectives of this study are to propose mix design method of concrete mixed with SSPCM and to evaluate mechanical behaviors of the concrete mixed with SSPCM manufactured according to the proposed mix design. Based on the previously reported material test result, the existing mix design of plain concrete(Concrete standard specification, 2009) is modified to consider reduction of strength in concrete due to the addition of SSPCM. To verify the proposed mix design, specimens are fabricated according to the proposed mix design and axial strength tests and three-point loading tests are performed. Test results show that compressive strengths of the tested specimens reach the designed strength even when two different mix ratios of SSPCM are used. From three-point loading tests, flexural stresses decrease as mix ratio of SSPCM increases.

• Membrane and Water Treatment
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• v.6 no.6
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• pp.451-476
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• 2015

Membrane distillation (MD), which can utilize low-grade thermal energy, has been extensively studied for desalination. By incorporating solar thermal energy, the solar membrane distillation desalination system (SMDDS) is a potential technology for resolving the energy and water resource problems. Small-scale SMDDS (s-SMDDS) is an attractive and viable option for the production of fresh water for small communities in remote arid areas. The minimum-cost design and operation of s-SMDDS are determined by a systematic method, which involves a pseudo steady state approach for equipment sizing and the dynamic optimization using overall system mathematical models. The s-SMDDS employing three MD configurations, including the air gap (AGMD), direct contact (DCMD) and vacuum (VMD) types, are optimized. The membrane area of each system is $11.5m^2$. The AGMD system operated for 500 kg/day water production rate gives the lowest unit cost of $5.92/m^3$. The performance ratio and recovery ratio are 0.85 and 4.07%, respectively. For the commercial membrane employed in this study, the increase of membrane mass transfer coefficient up to two times is beneficial for cost reduction and the reduction of membrane heat transfer coefficient only affects the cost of the DCMD system.