• 한국음향학회지
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• 제31권4호
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• pp.214-224
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• 2012

The objective of this paper is to design multichannel spherical loudspeaker array by considering various positioning methods such as Gaussian grid, Lebedev grid and packing method. For the spatial sound manipulation, which is to make desired sound field by controling multiple sound sources, the Kirchhoff-Helmholtz integral states that sound fields can be reproduced in terms of infinite control sources on the integral surface. But since we cannot control infinite number of sources for the implementation, we have to allocate finite number of sound sources which can approximately act as infinite number of sources. To manipulate sound field inside of a sphere (which is typical example of three dimensional array) by controlling sound sources on the surface, three methods of allocating sound sources, which are Gaussian grid, Lebedev grid and packing method, are reviewed. For each geometry, the performances of manipulation rendered by time-reversal operator and higher-order ambisonics are compared.

• 한국기계가공학회지
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• 제11권2호
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• pp.60-65
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• 2012

This paper deals with an CAE analysis and optimization of injection molding for a mobile phone cover. Two design goals are established in the optimization; one is to switch over the feed system from cold runner to hot runner for the purpose of reducing material costs, and the other is to minimize the warpage in order to improve product quality. By the full-factorial experiments for design parameters, we showed that the cold runner design could be changed to the hot runner design by replacing the current resin with a new resin of higher fluidity. In addition, we could significantly reduce the warpage of the cover product under the hot runner system by optimizing packing pressure and packing time.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2008년도 추계학술발표대회
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• pp.795-797
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• 2008

저궤도 관측위성은 지상으로 주기적으로 telemetry 를 전송함으로써 위성의 상태를 알리게 된다. 위성 내부에는 여러 종류의 수행 주가기 존재하며, telemetry 의 전송 주기는 초 단위를 갖는 것이 일반적이다. 위성의 개발 및 운영에 있어, telemetry 의 전송 주기보다 짧은 주기로 발생, 변경되는 데이터에 대한 지상으로의 전송이 필요하다. 여기서는 짧은 주기로 생성, 변경되는 데이터를 기존 telemetry 의 전송 주기에 맞추어 지상으로 전송하기 위한 위성 소프트웨어의 설계에 대해 간략히 소개한다.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.62-66
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• 2022

Semiconductor is one of the most internationally competitive areas among domestic industries, the major concern of which is the stability of the wafer manufacturing processes. The packaging process is the final step in wafer manufacturing. Problems in the wafer packaging process cause large losses. The vibrations are supposed to be the most important factors for the packaging quality. In this study, the structure of a packaging box was analyzed through experiments and computer simulations, and further the effects of design alterations to suppress the vibrations have been investigated. The final result shows that the vibrations can be reduced substantially to improve the stability of the structure.

• 응용화학
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• 제17권1호
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• pp.21-24
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• 2013

High performance count-current flow in packedtower design. Column that packed with Montz packing regular and dumped packing with Pall Ring, Hiflow Ring and Hackette have been represented high performance in vaccum rectification and absorption. The new correlating of these relationship based on the numerous results has been developed for process calculation and design. The results of laboratory or experimental pilot plant can be adopted directly for scale-up.

• 응용통계연구
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• 제29권7호
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• pp.1421-1428
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• 2016

본 논문에서는 포장 재질에 따라 쌀의 신선도가 어떻게 달라지는지 알아보기 위해 다변량 분산분석을 적용해 보았다. 쌀의 신선도는 쌀의 수분 함량과 식미치로 측정하였다. 포장 재질은 일반 종이와 종이 뒷면에 숯을 코팅한 종이를 비교하였다. 쌀을 보관하는 장소를 블록으로 간주하였다. 쌀의 수분 함량과 식미치를 나타내는 이변량 관측값에 대하여 완전 확률화 블록 설계에 의한 다변량 분산분석을 적용해 본 결과 포장 재질에 따라 유의한 차이를 보였다. 따라서 쌀의 수분 함량과 식미치 각각을 단일변량 관측값으로 간주하고 분산분석을 적용해 보았다. 그 결과 쌀의 수분 함량에 대해서는 포장 재질에 따라 유의한 차이를 보였으나 식미치에 대해서 유의한 차이 관측할 수 없었다.

• ETRI Journal
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• 제28권4호
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• pp.475-485
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• 2006

Network-on-chip (NoC) is an emerging design paradigm intended to cope with future systems-on-chips (SoCs) containing numerous built-in cores. Since NoCs have some outstanding features regarding design complexity, timing, scalability, power dissipation and so on, widespread interest in this novel paradigm is likely to grow. The test strategy is a significant factor in the practicality and feasibility of NoC-based SoCs. Among the existing test issues for NoC-based SoCs, test access mechanism architecture and test scheduling particularly dominate the overall test performance. In this paper, we propose an efficient NoC-based SoC test scheduling algorithm based on a rectangle packing approach used for current SoC tests. In order to adopt the rectangle packing solution, we designed specific methods and configurations for testing NoC-based SoCs, such as test packet routing, test pattern generation, and absorption. Furthermore, we extended and improved the proposed algorithm using multiple test clocks. Experimental results using some ITC'02 benchmark circuits show that the proposed algorithm can reduce the overall test time by up to 55%, and 20% on average compared with previous works. In addition, the computation time of the algorithm is less than one second in most cases. Consequently, we expect the proposed scheduling algorithm to be a promising and competitive method for testing NoC-based SoCs.

• Tribology and Lubricants
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• 제25권5호
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• pp.298-304
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• 2009

An angled labyrinth seal is used for the diaphragm-packing-ring seal design of steam turbine due to its leakage reduction characteristic. CFD analysis using FLUENT has been performed to predict leakage and determine an optimum slanted angle which yields the best leakage reduction. Results show that the optimum value of slanted angle is $-30^{\circ}$ independent of number of labyrinth teeth, inlet pressure, and tooth height to pitch ratio. 3D CFD analysis has been performed for predicting leakage of the angled labyrinth seal. Comparing with the result of 2D CFD analysis, 3D CFD analysis shows 1.4% smaller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.812-815
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• 2000

Injection molding process was taken to manufacture DC motor case that surrounds DC motor used as automobile parts. Up to now, DC motor case has been made by the deep drawing process or bending process of metal materials. Simulations of filling, packing and cooling processes were done by CAE tool like Moldflow software. Optimal delivery system was decided from the analysis of flow balance, and packing and cooling analyses were performed by using the design of experiment to minimize the volumetric shrinkage of molded part and the temperature difference between mold and part.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.644-651
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• 2001

The purpose of this study is to develop the improvement method of MOV(Motor Operated Valve) operability without major modification or change of MOV which needs a great expense and manpower. We studied valve stem lubrication, stem packing thrust and actuator control switch which could give an major effect to MOV operability, and found the some consequences. First, the stem/stem-nut friction coefficient and stem factor is significantly effected by stem lubrication state. Second, the measured packing thrust value is appeared higer than the design value for tested valves and the preparation of optimal value selection criteria is needed. Finally, optimization of MOV control switch is another major factor for MOV operability and structual integrity.