• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.208-210
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• 2002

xml 이 확산되면서 이를 저장하고 검색하는 방법들이 많이 제안되었다. 또한 데이터의 통합에 대하여 여러가지 방법을 제시하고 있다. 그러나 이런 방법들은 xml 이 가지고 있는 자유로운 확장성과 데이터의 통합이라는 관점에서 서로 상반된 면을 나타낸다. 이런 문제의 해결을 위해 W3C에서 제안한 이름공간에 대한 기존의 기능을 확장하고, 검색에 있어 사용자의 편리성을 위한 재질의 기법과 정확한 검색 결과를 위한 이름공간을 이용한 검색 시스템을 설계하였다.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.131-136
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• 2008

Silica- or titania-filled poly (vinylidene fluoride-co-hexafluoropropylene)-based polymer electrolytes were prepared by phase inversion technique using N-methyl-2-pyrrolidone and dimethyl acetamide as solvent and water as non-solvent. The polymer electrolytes were adopted to the lithium metal polymer battery using high-capacity cathode $Li[Ni_{0.15}Co_{0.10}Li_{0.20}Mn_{0.55}]O_2$ and lithium metal anode. After the repeated charge-discharge test for the cell, it was proved that the cell adopting the polymer electrolyte based on the phase-inversion membrane containing 40~50 wt% silica showed the highest discharge capacity (180 mAh/g) until 80th cycle and then abrupt capacity fade was just followed. The capacity fade might be due to the deposition of lithium dendrite on the polymer electrolyte, in which the capacity retention was no longer sustainable.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.248-254
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• 2013

Recently, contra-rotating propellers (CRP) having higher efficiency draw much attention since the EEDI regulation of IMO has been enforced. In this paper a numerical method based on the vortex lattice potential theory with a wake model and an experimental procedure with a newly built measuring device, specifically focusing on CRPs, are introduced. And they are applied to a series of CRP known to be designed for the purpose of improving EEDI. The numerical and experimental results showed good agreement explaining the characteristics of the CRP properly. The proposed method is believed to be effectively used for various CRP related studies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1723-1729
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• 2016

Digital watermarking is tried to get an optimum tradeoffs between its performance characteristics, robustness, transparency and capacity. This paper is, therefore, suggesting a watermarking technique that builds multiple barcodes in various frequency bands to implement embedded watermarks that is imperceptible and robust against various attacks. Even though a watermark technique with duplicated barcode watermarks embedded in various frequency bands can satisfy robustness as there is high possibility that watermarks embedded in an image remains after various attacks, the duplicated barcode data can weaken imperceptibility. Thus, to satisfy the conflicting characteristic requirements of watermarks, robustness and imperceptibility, different barcode data is embedded in each frequency band. The test shows that ownership authentication with the technique suggested in this thesis does not require specialized hardware, and extracted watermarks can be easily identified through a mobile barcode scanner app, which allows low complexity, low cost and swift identification.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.2
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• pp.49-61
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• 2003

Electronic voting schemes must provide universal verifiability and receipt-freeness, as well as basic properties such as privacy, eligibility, to make the election fair and transparent. But it is difficult to provide both universal verifiability and receipt-freeness because they are mutually contradictory in their objective. To date, most electronic voting schemes provide only one of these properties and those few that provide both properties are not practical due to heavy computational load. In this paper, we present an efficient electronic voting scheme that provides both properties. The proposed scheme uses a trusted third party called HR(Honest Randomizer) and requires only one-way untappable channels from HRs to voters. Among the schemes that assume only one-way untappable channel this scheme requires the least amount of computation. Among the schemes that provide both properties, this scheme uses the weakest physical assumption. We also discuss the security of the system and compare our scheme with other related schemes.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.83-83
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• 2017

수자원공학에서 일강수량 모의기법은 다양한 목적으로 활용되고 있지만, 일반적으로 홍수와 가뭄의 영향을 고려할 수 있는 수공구조물의 위험도 및 신뢰성 평가 및 수자원 계획을 수립하기 위한 입력 자료생성을 목적으로 활용된다. 유역 단위의 분석시 단일 지점에 대한 강수 모의 기법을 적용할 경우 각각의 지점에서 관측된 강수 자료의 시계열 및 통계치 특성이 효과적으로 재현되지만 공간적으로 발생하는 즉, 지점 간의 종속관계를 재현하지 못하는 문제가 발생한다. 이러한 이유로 공간적인 전이 특성이 있는 가뭄 분석 및 유역내 유출량의 공간적 변동 특성 분석에 단일지점별 모의 결과를 이용할 경우 관측 자료와 상반된 공간적 변동성으로 인하여 잘못된 가뭄 및 유출 분석 결과가 도출되는 문제점이 있다. 따라서, 실제적으로 발생하는 강수 특성을 반영한 유역 단위의 홍수 및 가뭄 등의 수문 분석을 위해서는 지점간의 종속성을 반영할 수 있는 다지점 강수 모의 모형의 적용이 필수적이다. 본 연구에서는 다지점 모의에 있어서, Wilks 모형의 지점별 시변동 특성과 공간상관성 재현 능력, HMM 모형이 갖는 강수 사상별로 분포된 양적 분포 패턴 재현 능력을 복합적으로 나타낼 수 있는 새로운 다지점 일강수량 모의 모형인 기계학습 기반 범주화 기법을 이용한 다지점 일강수량 모의 모형(ML-MRS)을 개발하였다. 또한, 지점별 강수량에 적용되는 확률분포모형은 Gamma 분포로 구성된 혼합모형을 적용하여 단일 확률 분포 모형의 자료 적합 문제를 개선하였다. 모의를 통한 일강수량 시계열 자료는 일 강수자료의 통계량을 효과적으로 모의하였으며, 다지점 모형의 모의 결과를 적용한 가뭄 모의 결과 관측 자료에서 나타나는 공간적 패턴이 재현되었다. 본 모형은 시 공간적 사상을 효과적으로 재현함으로서 지역의 변동특성을 반영한 가뭄, 홍수, 기상 현상 분석 등 활용도가 매우 높을 것으로 판단된다.

• Water for future
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• v.27 no.4
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• pp.69-84
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• 1994

The aim of this paper is suggest how to control the real time reservoir operation for the optimal operation of reservoir during the draught and the rainy season. The realease and the storage lead to the achievement or the deviation losses, higher or lower than the target level. Considering this deviation as one of the losses, putting the penalty on the losses, the way of optimal reservoir operation is discussed in order to minimize the penalty losses. This study draw the deviation losses' curve depending on the operation objectie for the Daechung Dam, and apply the optimal operation to the Dam by the linear programing technique, using the slope of the deviation curve as the losses coefficience for the objective function. Conclusively, in this paper I can combine the opposing subjects -the release and the storage- as one objective function by the deviation curve, and also show how to decide the criterion relate to the real time reservoir operation by analysing to what extent and how easily the objectives can be achieved, subject to the inflows.

• Journal of the Korean Geographical Society
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• v.36 no.4
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• pp.434-443
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• 2001

Differing from the existing method to optimize the statistical proximity, the new optimization method was developed to maximize the spatial proximity among the unit areas of choropleth map. 25 choropleth maps were made using 5 classification methods(maximum BEI, maximum TEI, equal interval, natural break, n-tile) for 5 classes(3∼7) and were analyzed to elucidate the effectiveness of classification methods on the basis of 3 evaluation indeces (TEI, BEI, $C_{F}$). The results from the maximum TEI and maximum BEI were evaluated as relatively stable and effective compared to those from other classification methods. But they showed the opposite trends owing to the trade-off relationships. Meanwhile, the resets from the natural break method got higher marks, which was also identified through the analysis using a new $alpha$-index.x.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.29-41
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• 2007

Structural design, like other complex decision problems, involves many trade-offs among competing criteria. Although mathematical programming models are becoming increasingly realistic, they often have design limitations, that is, there are often relevant issues that cannot be easily captured. From the understanding of these limitations, a decision-support system is developed that can generate some useful alternatives as well as a single optimum value in the optimization of steel frame structures. The alternatives produced using this system are "good" with respect to modeled objectives, and yet are "different," and are often better, with respect to interesting objectives not present in the model. In this study, we created a decision-support system for designing the most cost-effective moment-resisting steel frame structures for resisting lateral loads without compromising overall stability. The proposed approach considers the cost of steel products and the cost of connections within the design process. This system makes use of an optimization formulation, which was modified to generate alternatives of optimum value, which is the result of the trade-off between the number of moment connections and total cost. This trade-off was achieved by reducing the number of moment connections and rearranging them, using the combination of analysis based on the LRFD code and optimization scheme based on genetic algorithms. To evaluate the usefulness of this system, the alternatives were examined with respect to various design aspects.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.586-589
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• 2006

순수 함수형 언어에서 예외처리를 구현하는 것은 매우 까다로운 문제이다. 지연계산, 참조투명성과 같은 주요 특징은 예외 처리와 상반된 성질을 가지는 때문이다. 예외의 처리순서는 계산순서와 관계가 있고, 예외의 발생순서는 참조투명성과 밀접한 관계가 있다. 본 논문은 현재 하스켈(Haskell)에서 구현된 예외처리 방법의 분석을 통해, 프로그램 수행 시 효율적인 예외처리 방법에 대해서 제시한다. 합성된 프로그램에서 예외 발생할 때 예외가 전달되는 것을 사전에 차단하는 방법을 이용한다. 실제 예외가 발생한 프로그램을 작성하고, 프로파일링을 통하여 이 방법의 효율성을 점검한다.