• Water for future
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• v.18 no.4
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• pp.347-359
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• 1985

This study aims at the development of DP-Model for the establishment of monthly optimal operation policy of single multi-puppose reservoir by which the water demand of downstream can be satisfied under the various physical constraints. Series, A. B. C. of inflow are selected out of future monthly inflow data which are simulated form the past monthly average inflow of Andong dam site. the neight possible alternatives in each inflow series are established in order that Andong dam can supply the water demand of Nagdong main stream of 30% to 100%. Nextly, the reservoir rule curves is derived for each alternative by the detailed seguential analysis of stroage, future inflow and water demand based on the reservoir continuite equation. Then, and alternative which can satisfy the objective function of system based on the rule curves in the exteream is determined as an optimal operation policy from the application of developed DP=Model.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1152-1155
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• 2009

기후변화로 인해서 발생하는 여러 영향 중 가뭄 및 홍수와 같은 극치강수량의 변동은 사회 경제적으로 파급효과가 크기 때문에 더욱 주목을 받고 있다. 이러한 점을 효과적으로 평가하기 위해서 본 연구에서는 지역규모기후변화시나리오와 비정상성 Markov Chain 모형을 이용한 Downscaling 기법의 적용 등 일련의 과정을 통해 기후변화를 반영한 지점별 일강수계열을 생성하고 이를 대상으로 다양한 분석을 실시하였다. 수문기후변화시나리오 작성 과정을 요약하면 다음과 같다. B1과 A2 지역규모 기후변화시나리오가 사용되었으며 이를 비정상성 Downscaling 기법의 입력 자료로 활용하여 일강수량 자료를 모의 발생하였다. 이러한 과정을 우리나라 기상청 산하 60개 강우지점에 적용하였으며 극치강수량의 빈도를 추정하기 위해 부분기간 계열과 전기간 계열 자료로 재생산하여 극치분석을 실시하였다. 극치분석결과 강수량에 대한 공간적인 편차가 심하게 발생하고 있으며 강수량의 변동성 또한 매우 크게 나타나고 있는 것을 확인할 수 있었다. 이러한 특성은 선택된 시간 및 사용된 기후변화시나리오에 따라 다르게 나타나고 있으며 한 가지 주목할 점은 기후변화정도가 심한 A2 시나리오와 정도가 약한 B1 시나리오를 비교할 때 온도와 같은 뚜렷한 차이점은 발견할수 없었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1330-1334
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• 2012

The submarines reach their weakest point when they sail on the surface to operate snorkel and periscope. At this period, however, there lies a high possibility that the submarines are detected by non-acoustic sensors such as radars, IR signatures, and human observations. In this paper, the non-acoustic stealth was adopted on the mast and periscope of submarines so as to overcome their vulnerability of being easily detected in this given situation. First of all, the non-acoustic detection sensors were investigated and the stealth methods were analyzed. And multi-layered structures consisting of RAM layer, IR layer, and Camouflage layer were proposed on the surface of the submarine. As a results, multi-layered structure was suggested with 3~5 mm of a magnetic material such as ferrite for RAM layer, 1~2 mm of ceramic or nickel for IR layer, and sea-blue paint for Camouflage layer.

• Water for future
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• v.18 no.1
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• pp.75-83
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• 1985

The applicability of ARMA(1, 1) multiseason model, which is in the beginning stage of active researches in the field of synthetic generation is evaluated with the streamflow data at the Nakdong stage gauging station on the main stem of the Nakdong River. The method of parameter estimation for the modelis reviewed and the statistical analysis of the generated seasonal streamflows such as corrlogram analysis and the computation of moments is made. The results obtained by ARMA(1, 1) multiseason model are compared with the historical streamflow data and also with those by two other multiseason models, namely, Thomas-Fiering model and Matalas AR(1) multiseason model. The seasonal streamflows grnerated by three multiseason models were annually summed up to form respective annual flow series whose statistics were compared with those of the annual flow series generated by three annual models, namely, AR(1), Matalas AR(1), and ARMA(1, 1) annual models. The possibility of ARMA(1, 1) multiseason model for the simultaneous generation of seasonal and annual streamflows is also evaluated.

• Journal of Engineering Education Research
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• v.13 no.6
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• pp.111-121
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• 2010

The purpose of this study is to develop customized technological leadership camp programs in order that engineering students can be techno-leaders in the future. The camp programs were developed by systemic instructional design methodology. A framework of technological leadership was developed through literature reviews and cases analysis, and key competencies on technological leadership were drawn through needs analysis using importance-performance analysis. The participants for needs analysis were 202 engineering students in A university and 22 managers and directors in the companies cooperated with A university. Camp programs focused on key competencies on technological leadership were developed: basic course and advanced course. The programs modified through twice experts committee.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.1
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• pp.34-36
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• 1997

In this paper, we introduce the design method using CAE(Computer Aided Engineering) which is profitable in the compatibility and standardization of the developed product and the reduction of construction time and price to develop and design a machine equipment. Particularly, we select the standard model to design or develop from the large machinery to the super precision one, extract the peculiar characters of the model by the close analysis of the physical and technical part, can predict the previous result of experimental characteristics on objective dimensions through the analogical mathematical analysis, and can induce the design model demanded by user investigating optimal data in advance. We present the analogical algorithms and process method of design factors and restriction factors in the systematization design with computer. Then we analyze step functions for each systematization equipment and induce the process of technical data with actuator model.

• Polymer(Korea)
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• v.36 no.2
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• pp.190-195
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• 2012

Interfacial and rheological properties of selected hydrogel formulations were studied to understand the contact-lens comfort in end use. It was concluded that protein adsorption from aqueous solution decreased monotonically with increasing surface energy (water wettability) of tested hydrogels. Also, it has revealed that friction coefficient of polydimethylsiloxane-polyvinylpyrrolidone (PDMS-PVP) was significantly larger that 2-hydroxyethyl methacrylate (HEMA) based hydrogels. Interestingly, in artificial tear solution, friction coefficients of HEMA based hydrogels were larger than silicone hydrogels.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1448-1452
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• 2010

최근 기상변동성 증가 및 기후변화 영향으로 수문순환과정이 과거와는 다른 양상으로 전개되고 있으며 전반적으로 극치사상의 빈도 및 강도의 증가현상이 지배적이다. 이러한 영향을 정량적으로 검토하기 위해서 경향성분석 방법 등이 도입되어 극치수문사상의 변동경향을 평가하는데 이용되고 있다. 대표적인 방법으로 선형회귀분석, Mann-Kendall 경향성 분석 등이 있으나 기본적인 가정(assumption)의 제약으로 극치수문자료 계열의 특성을 효과적으로 분석하는데 무리가 있다. 대표적이고 일반적으로 적용되는 선형회귀분석의 경우 자료가 정규분포(normal distribution)의 특성을 가질 때 유효한 방법으로서 극치수문자료와 같이 Heavy Tail를 가지는 분포특성을 표현하는 데는 무리가 따른다. 이밖에도 기존 선형회귀분석을 극치수문자료에 적용할 경우 추정된 결과를 수자원설계의 관심사항인 빈도해석 등에 직접적으로 연계시켜 해석할 수 없는 단점이 있다. 이는 자료계열의 분포특성을 정규분포로 가정하기 때문에 발생하는 문제로서 극치수문자료계열의 분포 특성을 반영할 수 있는 방법론의 개발이 필요하다. 본 연구에서는 이러한 점을 개선하기 위해서 극치분포(extreme distribution)를 선형회귀분석에 적용하는 비정상성빈도해석(nonstationary frequency analysis) 방법론의 개념을 제시하고자 한다. 비정상성빈도해석을 위해서 Bayesian 기법이 도입되며 Bayesian 기법의 특성상 관련변수들이 사후분포(posterior distribution)로 귀결되기 때문에 경향성에 대한 정량적이고 확률적인 분석이 가능한 장점이 있다. 본 연구를 통해 개발된 방법론은 국내외 주요 강수지점에 대해서 적용되며 경향성, 분포특성, 빈도별 강수량에 대한 체계적인 분석이 이루어진다.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.3
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• pp.127-142
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• 1998

This study is a comparative analysis of the usage level of domestic academic journals in each discipline. The purpose of this study is that the results from this analysis can be used as basic data for evaluating domestic journals which is being done in every university. I atopted citation analysis as research methods target to dissertation and core journal in each discipline. From this analysis I got some results that can be applied as a tool for evaluating journals. First, there is distindtive difference in degree of reliance on the domestic journals, therefore we have to prepare different check points for each discipline. Second, if high rank journal can't take rule power under $50\%$, we must prepare another pertinent check points to evaluate journals efficiently.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.4
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• pp.177-188
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• 1993

Model parameters of the WASP4 applied to Lake Paldang were estimated. The methodology is based on grouping water quality constituents and relevant parameters and successively estimating each group of parameters by a trial-and-error procedure. Chlorophyll a, nitrogen cycles, phosphorus cycles, BOD and DO were simulated at the complexity level 4. A water budget analysis using the monthly records of reservoir inflows and outflows in 1989 and 1990 was made to determine seasonally-averaged flowrates at model boundaries. Estimated flowrates were used, together with the seasonal average of water quality measurements in 1989 and 1990 for the calibration and verification, respectively, of the model. Grouping water quality constituents and associated parameters proved to be efficient in estimating a number of model parameters. From the results of model calibration and verification, it was found that quantitative evaluations of nonpoint and benthic sources of organic matters are essential. Benthic sources near the entrance of the Kyeongancheon were the most significant.