• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.383-387
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• 2007

In this paper the design of the discharge cleaning system for KSTAR vacuum vessel is described. We first discuss about the parameters which are related the efficiency of discharge cleaning. The RG(RF-assisted Glow) discharge which has the ignition and sustain pressure lower than those in the case of DC discharge, thus has the higher efficiency of discharge cleaning. So we adopt the RG discharge, in practical design, for KSTAR discharge cleaning system. For uniformity of the cleaning effect, we plan to install two discharge cleaning systems in A- and I-port of the KSTAR vacuum vessel. The designed system will be adapted for the study of the fuel recycling and of the boronization as well as the discharge cleaning of the KSTAR vacuum vessel.

• Water for future
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• v.24 no.2
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• pp.81-95
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• 1991

For investigation of the interaction of tide and river flow, the derived equations are solved analytically using the approximation method of perturbation. The convective inertia and nonlinear bottom friction terms are included in the derivations. The harmonic analysis is applied to decompose the complicated interaction of the freshwater discharge with various constituents of tide into its individual interaction with each constituent. In this study, four main constituents(M2, S2, Kl, 01) are included. The relations of dimensionless parameters of the tide, especially the dimensionless damping modulus, are then determined for each solution. The results show that analytical solution of dimensionless damping modulus underestimates the measured value obtained from harmonic analysis. Results of water level obtained by applying the analytical model to a tidal reach of the Keum River in the years 1981 and 1982 show very good agreement with those obtained from the harmonic analysis.

• Water for future
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• v.9 no.1
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• pp.101-105
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• 1976

This Study is developed in order to determine the probability of a raintall depth of short duration in Seoul as considering the profect life and the factor of safety of hydraulic structures. The raw annual maximum rainfall data are selected from 1915 to 1974 about short duration (10min-120min.) in Seoul. The selected data are treated by frequency analysis, and the hypothesis that the distribution fuction of the raw data is normal Distribution is performed by chi-square test that signifcance level has 5%. With the parameters (mean and standard deviation) of the accepted distribution function, the probabilitn of a rainfall depth can be easily determined on the graph which is made on this paper.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1608-1613
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• 2007

최근들어 수자원 분야에서 GIS(Geographic Information System)의 활용에 대한 많은 연구가 이루어지고 있다. 수자원 관련 분야에 있어서 GIS는 수문현상에 영향을 미치는 기상학적인 요인, 토양, 토지이용도, 배수 유역의 형태 등 수문정보를 획득하기 위한 수단으로 사용될 수 있을 뿐만 아니라, 유역에서의 지형학적, 기후학적 특성을 시간과 인력을 절약하여 정량화할 수 있다는 것이 입증되고 있다. 하천에서의 유출량 추정은 강우, 수위와 같은 수문데이터의 신뢰도에서 많은 문제점이 야기되고 있다. 따라서 모의 입력매개변수의 중요요소인 지형정보의 경우 GIS 기법을 이용할 경우 기존 방법과는 달리 신뢰성 있는 정보를 획득할 수 있으므로 모형의 결과를 개선하는 데 도움이 될 것이다. 본 연구에서는 미국의 Environmental Modeling Research Laboratory(EMRL)에서 개발한 지리정보시스템과 수문유출모형이 접목된 WMS(Watershed Modelling System) 모형을 HEC-1 모형과 연계하여 낙동강수계 제1지류인 회천유역 개진1, 개진2 지점의 유출 해석을 실시하였다. GIS와 결합된 홍수유출모형인 WMS를 이용하여 유역 내의 지형특성인자 및 하천망을 추출하였으며, 유출해석은 WMS에 내재된 HEC-1을 이용하였다. 유효강우량의 산정을 위해 SCS CN 값을 사용하였으며, CN 계산을 위해서는 토지이용도 토양도를 이용하였다. 합성단위도법은 SCS 무차원 단위도법을 사용하여 유출을 모의하였다.

• Journal of Information Management
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• v.29 no.3
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• pp.1-26
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• 1998

The loop is a fundamental for the parallelism exploiting as it has a large portion of execution time for sequential Java program on the parallel machine. This paper proposes the method of exploiting the implicit parallelism through the analysis of data dependence in the existing Java programming language having a single loop structure. The parallel code generation method through the restructuring compiler and the translation method of Java source program into multithread statement, which is supported in the level of the Java programming language, are also proposed here. The performance test of the program translated into the thread statement is conducted using the trip count of loop and the thread count as parameters. The restructuring compiler makes it possible for users to reduce overhead and exploit parallelism efficiently in the Java programming.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.567-578
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• 2013

A microbial fuel cell (MFC) is a bio-electrochemical device that converts chemical energy in the chemical bonds in organic compounds to electrical energy through catalytic reactions of microorganisms under anaerobic conditions. Power density and Coulombic efficiency are significantly affected by the types of microbe in the anodic chamber of an MFC, configurations of the system and operating conditions. The achievable power output from MFC increased remarkably by modifying their designs such as the optimization of MFC configurations, the physical and chemical operating conditions, and the choice of biocatalysts. This article presents a critical review on the recent advances made in MFC research with the emphasis on MFC configurations, optimization of important operating parameters, performances and future applications of MFC.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.23-30
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• 1998

An estimation of seismic risk parameters by seismic zones of the Korea Peninsula in order to calculate the seismic hazard values using these was erformed. Seven seismic source zones were selected in consideration of seismicity and geology of Korean Peninsula. The seismicity parameters that should be estimated are maximum intensity, activity rate and b value in the Gutenberg - Richter relation. For computation of these parameters, least square method or maximum likelihood method is applied to the earthquake data in two ways; the one for the data without maximum intensity and the other with maximum intensity. Earthquake data since Choseon Dynasty is regarded as complete and estimation of parameters was made for these data using above two ways. And recently, a new method is published that estimate the seismicity parameters using mixed data containing large historical events and recent complete observations. Therefore, this method is applied to the whole earthquake data of the Korean Peninsula. It turns out that the b value computed considering maximum intensity is slightly lower than that computed considering without maximum intensity, and it becomes still lower when the incomplete data prior to Choseon Dynasty is used. In the case of the activity rates, the values obtained without maximum intensity and that with maximum intensity are similar, though they are lower when the incomplete data is used. The values of maximum intensities are usually lower when considering incomplete data. In the seismic source zone including the Yangsan Fault zone, however, the values are higher when considering the incomplete data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.459-466
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• 2001

The floor vibration aspect for building structures which are in need of large open space are influenced by the interrelation between natural frequency and working loads. Structures with a long span and low natural frequency have a higher possibility of experiencing excessive vibration induced by dynamic excitation such as human activities. These excessive vibrations make the residents uncomfortable and the serviceability deterioration. Need formulation of loads data through actual measurement to apply walking loads that is form of dynamic load in structure analysis. The loads induced by human activities were classified into two types. First type is in place loads. the other type is moving loads. A series of laboratories experiments had been conducted to study the dynamic loads induced by human activities. The earlier works were mainly concerned to parameters study of dynamic loads. In this Paper, the walking loads have been directly measured by using the measuring plate in which two load cells were placed, the parameters, the load-time history of walking loads, and the dynamic load factors have been analyzed. Moreover, the shape of the harmonic loads which were gotten by decomposition the walking loads have been analyzed , and the walking loads modeling have been carried out by composition these harmonic loads derived by functional relation.

• Water for future
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• v.21 no.4
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• pp.407-414
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• 1988

The purpose of this paper is to study the following ; (1) how the stability and sensitivity of a given stream water quality model can be analyzed theoretically by means of the stability theory and the sensitivity theory, and (2) point out that the results of this study prove that numerical analysis for the given stream water quality model is reliable, and the model is sensitive for the variations of parameters. A stability theory which is described by the infinite Fourier series is used to analyze the numerical scheme of the model. The numerical shheme is used a backward implicit scheme. a sensitivity theory which is described by the first order linear vector equation is used to analyze theoretically the effect of variations of water quality parameters such as BOD loads, flow rate, temperature. The results of sensitivity theory are of general applicability and are presented in a analytical form. The results of this study seems to be satisfactory for the reliability of stream water quality model with respect to the numerical scheme and the variations of the water quality parameters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2541-2551
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• 1996

Human visual systems are sensitive to noise on the flat intensity area. But it becomes less sensitive on the edge area. Recently, many types of spatially adaptive image restoration methods have been proposed, which employ the above mentioned huan visual characteristics. The present paper presents an adaptive image restoration method, which increases sharpness of the edge region, and smooths noise on the flat intensity area. For edge detection, the proposed method uses the visibility function based on the local variance on each pixel. And it adaptively changes the regularization parameter. More specifically, the image to be restored is divided into a number of steps from the flat area to the edge regio, and then restored by using the finite impulse response constrained least squares filter.