• 전기학회논문지
• /
• 제59권8호
• /
• pp.1406-1415
• /
• 2010

As process technology for semiconductor goes beyond the ultra-deep submicrometer regime, interconnect reliability on a chip has become a serious design concern. As process parameters scale, interconnect widths are reduced rapidly while the current flowing through the interconnect does not decrease in a proportional manner. This trend increases current densities in metal interconnects which may lead to poor reliability for electromigration. Hence, it is critical to estimate the current amount passing through the interconnects earlier in semiconductor design stages. The purpose of this paper is to propose a fast yet accurate current estimation technique that can offer not only analysis time equivalent to those offered by the previous approximation methods but also a relatively precise estimation by using closed-form equations. The accuracy of the proposed technique was confirmed to be about 8 times better on average when compared to the previous work.

• 한국대기환경학회지
• /
• 제14권4호
• /
• pp.387-392
• /
• 1998

Recently, among after-treatment devices which have high possibility of utility, diesel oxidation catalyst (DOC) is concerned over the world. DOC oxidizes pollutants by means of activate-reaction during by -passing in the catalyst, in doing so, conversion efficiency of PM, CO and HC is high, and this device does not have an effect on engine performance because back pressure is not nearly increased. But, as a small amount of sulfur content in fuel is oxidized, it makes sulfate, which is absorbed on the surface of catalyst. So, in this study, the experiment is carried out by means of using ordinary fuel (0.1wt%) and low sulfur fuel (0.05wt%) with DOC, and the emission gas of diesel engine is measured.

• 기술사
• /
• 제16권1호
• /
• pp.4-12
• /
• 1983

데이터통신은 역사적으로 볼 때 전용회선이용시기로부터 공중전화교환망개선을 거쳐 데이터 전용교환망 구축으로 발전해 간다. 초기단계부터 분리독립된 데이터전용교환건설은 방대한 비용이 소요되므로 어느 나라도 이런 방법을 택하지 않는다. 한국도 전용회선시대를 지나 금년상반기(1983)에는 공중전화교환망을 데이터통신에 개선할 것과 금년하반기에는 데이터통신공중교환기인 Packet교환기를 설치할 계획이다. 이 논문은 서울의 공중교환전화선의 특성을 측정한 것과 한국의 데이터통신의 장래의 발전을 전망한 것이다.

• 설비공학논문집
• /
• 제15권2호
• /
• pp.137-143
• /
• 2003

In the forming of an integrated system of radiant floor cooling and dehumidifying, chilled coil can be used for cooling and dehumidification. Therefore, it is necessary to find the efficient control method which can eliminates latent load efficiently. This study has been conducted to find this method by dividing the dehumidification system into 3 types according to the control variables and analyzing characteristics of each system. To prevent the floor surface condensation, the amount of condensation can be manipulated by water temperatures, water flow rates in chilled coil, and air flow rates passing by it. So dehumidification system control can be divided into constant air flow control and variable air flow control. Regarding dehumidification control, variable air flow control, which eliminates latent load rather than sensible load, is preferable to constant flow control.

• 한국정밀공학회지
• /
• 제17권5호
• /
• pp.100-107
• /
• 2000

The hydraulic couplings have been widely used in industries, automobile, and power-station drives including ships. A mathematical analysis by which the design and application of hydraulic couplings are made is used in conventional design formulae and general roto-dynamic theories. The fluid flow of hydraulic couplings can be considered to have two component, one circumferentially about the coupling axis, and the other passing fluid from the pump to the turbine in the plane of the coupling axis. Tests have been carried out on the full-scale production coupling. The performance test consists of taking measurement of torque of the fluid coupling for three different amount of working fluid inside with various loads to the output shaft. The purpose of this research is to construct the experimental test equipments and to establish a series of performance test for the domestically developed hydraulic couplings, and to obtain experimental results which can be used to improve the performance of the hydraulic coupling and to solve the practical problems confronted in operation.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.262-265
• /
• 2008

We design level 1 traffic thematic map for common data structure. Level 1 means the road that can passing cars. If public office and private company use this form, they can save amount of money from overlapping update. And widely use of traffic analysis, navigation and traffic information system. For design common data structure we compared several data structure(traffic thematic map, ITS standard node/link, Car navigation map), and generalization these characteristic data. After generalization we considered about application parts. It can use of public part(traffic analysis, road management, accident management) and private part(car navigation, map product, marketing by variable analysis) etc.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2005년도 춘계 학술대회논문집
• /
• pp.123-127
• /
• 2005

The numerical analyses of the complicated flows are widely attempted in these days. Because of the enormous demanding memory and calculation time, parallel processing is used for these problems. In order to obtain calculation efficiency, it is important to choose proper domain decomposition technique and numerical algorithm. In this research we enhanced the efficiency of the CFDS code developed by ADD, using parallel computation and newly developed numerical algorithms. For the huge amount of data transfer between blocks non-blocking method is used, and newly developed data transfer algorithm is used for non-aligned block interface. Recently developed RoeM scheme is adpoted as a spatial difference method, and AF-ADI and LU-SGS methods are used as a time integration method to enhance the convergence of the code. Analyses of the flows around the ONERA M6 wing and the high angle of attack missile configuration are performed to show the efficiency improvement.

• 정보처리학회논문지A
• /
• 제12A권5호
• /
• pp.421-426
• /
• 2005

대규모 병렬 연산에 있어서, 계산 노드 혹은 이들을 연결한 통신 네트워크의 장애는 연산 실패로 끝나며, 소중한 계산 시간이 낭비된다. 그러나 현재의 MPI 표준은 이에 대한 대안을 제시하지 않고 있다. 본 논문에서는, 비표준의 무정지형 MPI 라이브러리가 아닌 MPI 표준 함수들만을 사용하여, MPMD 방식의 비동기 연산을 도입한 응용 수준의 무정지형 선형 시스템의 해법을 제안한다.

• 한국생산제조학회지
• /
• 제25권5호
• /
• pp.380-385
• /
• 2016

Railway tracks are repeatedly overstressed and damaged owing to increase in passing tonnage and numerous contact cycles between wheels of train and rails. In order to ensure safe train operation, heat-treated rails are used in addition to regular inspection and maintenance of these rails. Normal rails were treated using ultrasonic nanocrystal surface modification (UNSM) to strengthen the surface of rails. A few changes in surface properties were detected with respect to hardness and compressive residual stress after UNSM treatment. Wear and rolling contact fatigue tests were performed using rails whose surfaces were hardened by UNSM and heat-treated rails. The amount of wear and fatigue life cycles were measured to estimate the effect of UNSM on the rail material. The material of the surfacehardened rail showed improved wear and rolling contact fatigue properties.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2000년도 학술발표회 발표논문집
• /
• pp.333-339
• /
• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas funnel connected to combustion chamber of greenhouse heating system. The experiment heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas funnel, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amount by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air pipes and exhaust air passages crossing the pipes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through funnels.