• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.847-850
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• 2004

최근 인터넷이 보편화됨에 따라 상품구입을 위한 검색서비스는 필수가 되었다. 특히, 동일한 품목에 대해 소비자가 원하는 상품을 검색하고, 판매자에 따른 상품 가격의 차이를 비교하는 서비스가 지원되고 있다. 하지만 가격 비교를 제공하는 사이트들은 각 가격 비교 사이트별로 확보하고 있는 쇼핑몰들만을 대상으로 검색을 하기 때문에, 동일 상품에 대하여 제시하는 가격이 다를 수 있다. 따라서 소비자는 정확한 최소의 가격을 알기위해 많은 시간을 소요하며, 수시로 변동되는 상품의 최소 가격에 대한 정확한 정보를 얻기 어렵다. 따라서 본 논문에서는 가격 비교를 제공하는 사이트들에 상품 가격 비교 정보를 요청하기 위하여 이들에게 각기 질의를 보냄으로써 소비자가 찾고자하는 상품과 최소 가격을 빠르고 정확하게 서비스해줄 수 있는 메타 검색기법을 이용한 이동 에이전트 기반의 상품 가격 비교 검색 모델을 설계 및 구현한다.

• Journal of Climate Change Research
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• v.1 no.2
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• pp.163-177
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• 2010

This study analyzes the economies of photovoltaic systems in an apartment complex of 1,185 households, in cases of feed-in tariff and subsidy for solar home program of the government. When including the revenue only from electricity sales, NPVs of subsidy and that of feed-in tariff are -560 million KRW and -87 million KRW respectively. With the avoided social cost included without the revenues from CERs, NPVs of subsidy and feed-in tariff are -556 million KRW and -84 million KRW respectively. With the revenues from CERs, NPV of subsidy is -526 million KRW and NPV of feed-in tariff is -54 million KRW. As results of sensitivity analysis based on the changes in capital costs and discount rates, while all scenarios with subsidy including the revenues from CERs are not commercially viable, all scenarios with feed-in tariff exclusive of the revenues from CERs are commercially viable when discount rate is less than 7.2% or capital cost is less than 6,840 thousand KRW/kW. In the cases that include the avoided social cost, while all scenarios with subsidy including the avoided social cost as well as the revenues from CERs are not commercially viable, all scenarios with feed-in tariff are commercially viable without the revenues from CERs when discount rate is less than 7.2% or capital cost is less than 6,856 thousand KRW/KW. The results indicate that the changes in discount rates do not influence the revenues from CERs, but the revenues from electricity sale. Considering that the number of apartment complex and the positive environmental and social benefits from PV system, government needs to promote its diffusion.

• Analytical Science and Technology
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• v.19 no.3
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• pp.239-243
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• 2006

This method is used for the determination of itraconazole in human plasma by liquid-liquid extraction and high performance liquid chromatography. Felodipine was used as an internal standard. After extraction of the plasma with diethyl ether, the centrifuged upper layer was then transferred. The supernantant was evaporated and then reconsituted with mobile phase. The mobile phase was composed of 10 mM ammonium acetate adjusted to pH 7 by phosphoric acid with a flow rate of 0.2 mL/min. A C18 reversed-phase column with a pre-column was used as the analytial column. Linear detection responses were obtained for itraconzole concentration range for 2~1,000 ng/mL. The correlation coefficient of linear regression($R^2$) was 0.9991, limit of quantification (LOQ) was 2 ng/mL, reproducibility was less than 10.8 %, and accuracy was 97.2~108.2%. This method has been successfully applied to the pharmacokinetic study of itraconazole in human plasma.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.959-968
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• 2012

HEC-RAS has been applied to simulate water level variation in the Ara waterway during the flood season. To support decision making necessary for operation of the hydraulic structures especially during the flood season, it is important to consider various factors such as water level of the Han River, Gulpo River, and tidal level of the west sea in conjunction with operation of the hydraulic structures such as the Gyulhyun Weir, the West sea gate, and pumping stations. Especially for operation of the west sea gate, the Rule-script option was employed to determine the opening height considering the variation of the water level in the waterway and the west sea simultaneously. For model verification, comparison of water level computed at the upstream and downstream of the regulation weir shows a good agreement with observed data measured during the flood event in September 2010. The HEC-RAS model developed in this study will contribute to support operation of the waterway during the flood season.

• Journal of the Korean Geographical Society
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• v.51 no.4
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• pp.525-539
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• 2016

This study attempts to predict the changes in the spatial distribution of occupational employment in Korea by applying Markov Chain Model. For the purpose we analyze the job-related migration pattern and estimate the transition probability with the last six years job-related migration data. By applying the Chapman-Kolmogorov equation based on the transition probability, we predict the changes in the spatial distribution of occupational employment for the next ten years. The result reveals that the employment of professional jobs is predicted to increase at every city and region except Seoul, while the employment of elementary labor jobs is predicted to increase slightly in Seoul. In particular, Gangwon-do and Chuncheongdo are predicted to increase in the employment of all occupational jobs.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1129-1138
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• 2011

Small area estimation has received significant intention in recent years due to a growing demand for reliable local area statistics. Traditional area-specific direct estimates based solely on sample survey data in the areas of interest do not provide adequate small area precision; however, design-based indirect local area estimators borrow strength from sample observations of related areas to increase the effective sample size. Design-based indirect estimation methods such as synthetic and composite estimators are considered to adjust local area unemployment rate estimates in the Korean Economically Active Population Survey. This study suggests an efficient alternative to minimize the cost to construct the unemployment rate of a local area through simulation under the condition that we can maintain a certain level of CV for the estimates. We obtained the results that the composite estimators using a sample size greater than 10 are more stable and significant at the level of CV 25% in our design scheme.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.2
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• pp.159-168
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• 2020

Current residential electricity rates, which are charged regardless of consumption patterns, have a problem of restricting consumer choice. In order to improve the problem, the Korea government started a demonstration project based on Time-Of-Use(TOU) pricing from September 2019. However, the analysis of its effect is still limited. This study analyzed the changes and limitations of TOU pricing compared to the current progressive pricing. The result showed that the high rate payer's bill decreased by up to 33.8 % while the low rate payer's bill increased by up to 117.7 %. This can lead to the problem of accepting electricity rates from a social point of view. In this study, TOU pricing based on progressive pricing was proposed to overcome the problem. The results presented the rate changes depending on the power consumption patterns while decreasing the average rate change from 32 % to -1.9 %. It means that the proposed pricing can support the TOU effect while maintaining the framework of the existing progressive pricing.

• Environmental and Resource Economics Review
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• v.23 no.3
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• pp.473-496
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• 2014

This paper intends to test the non-linear relationship between $CO_2$ emissions and income by employing cointegration model of the time-varying income elasticity. We select France, UK, Italy, Japan, US, China, India, Mexico and Korea and use non-parametric time series analysis on each country in order to estimate its own effect of income on $CO_2$ emission. The main results indicate that the $CO_2$ emission-income elasticities vary over time and the income elasticities of the Annex I countries tend to be higher in absolute terms than those of developing countries. In addition, we find that emission-income elasticities decrease for Annex I countries over time, whereas those for developing countries increase.

• KIISE Transactions on Computing Practices
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• v.23 no.8
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• pp.459-465
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• 2017

Although the performance of computer hardware is increasing due to the development of manycore technologies, software lacking a proportional increase in throughput. Functional languages can be a viable alternative to improve the performance of parallel programs since such languages have an inherent parallelism in evaluating pure expressions without side-effects. Specifically, Haskell is notably popular for parallel programming because it provides easy-to-use parallel constructs based on monads. However, the scalability of parallel programs in Haskell tends to fluctuate as the number of cores increases, and the garbage collector is suspected to be the source of this fluctuations because it affects both the space and the time needed to execute the programs. This paper uses the tuning tool, GC-Tune, to improve the scalability of the performance. Our experiment was conducted with a parallel plagiarism detection program, and the scalability improved. Specifically, the fluctuation range of the speedup was narrowed down by 39% compared to the original execution of the program without any tuning.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.5
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• pp.605-614
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• 2005

In this paper, we present the design and implementation of an agent knowledge and QoS tuning methodology to improve the flexibility of agent-based flexible video-conference system. In order to improve the flexibility during video-conferencing, we propose a new T-INTER(Tuning-INTER) architecture of knowledge part in video-conference manager (VCM) agent in which an automatic QoS parameter tuning method is imbedded. The flexible video-conference system structured based on the proposed architecture can cope with the changes in service quality required by users. The VCM agent cooperates with other agents by protocols and executes the automatic QoS parameter tuning task whenever needed. By the tuned parameters, the system is able to flexibly cope with the internal or external changes and the burden of users can be decreased. In the experimental section, it is shown that our proposed system outperforms the existing system.