• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.61-92
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• 2003

As an extension of previous researches with the conclusion that the announcement of adopting stock options generates positive abnormal returns, this paper examined whether the abnormal return changes over time or varies depending on the number of stock options granted. Empirical analysis was made to find whether the announcement of stock option awards has the same response in the stock market from the early days when stock option plans had been introduced in the Korean stock market till today when it was widespread. Results indicate that the announcement effect had been on a gradual decline since 2000. In addition, it is found that if a company announces stock option awards several times, the abnormal return gradually declines in proportion of the number of stock options granted. This implies that as the stock option awards become widespread, the positive effect that the announcement of adopting stock options generates as news has been on a relatively steady decrease. In short, it leads to a conclusion that the more companies grant stock options, and the more stock options a company announces, the less impact it has on the increase in the firm's value.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.63-73
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• 1994

Weight loss accelerating agents, TDACW and TTAMW were prepared by adding water to n-tetradecyldimethylbenzylammonium chloride(TDAC) and n-tetradecyltrimethylammonium methyl sulfate(TTAM) synthesized in our lab. On weight loss finishing of PET fiber with NaOH and TDACW or TTAMW, TDACW showed much more weight loss than TTAMW. Optimum concentration was about $8g/{\ell}$, treatment time 60~90min and treatment bath ratio 1:40~1:50. Density and crystallinity increased with weight loss and tensile strength decreased with weight loss. From the reaction mechanism of weight loss accelerating agent and PET fiber, weight loss accelerating agent was proved to function as a catalyst and the surface structures of PET fibers treated with weight loss accelerating agent were characterized with SEM.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.137-142
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• 1998

This study aims to examine appropriate kinds of pan oil to release a cake from the pan coated with polyether sulphone and to prove the change of acid value and peroxide value during the process of baking. The major factor effecting the rate of release of the cakes from the pan was properties of the oils rather than the additives. The releasing rate appeared higher as the iodine value was lower. The highest releasing rate was found in the sample, which was made of coconut oil plus 2% of wax, 2% of lecithin. The changes of acid value of the pan oil between the beginning and after baking was little different. In contrast, Peroxide value showed a great change after baking.

• Journal of Aquaculture
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• v.16 no.4
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• pp.223-228
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• 2003

An exfoliation, the detachment of juvenile abalones from a culture substrate, is essential for selection and population density control in abalone culture. Physical instruments and anesthetics are currently available for the exfoliation but the latter is regarded as more effective in reducing physical damage to the animals. In the present study, urea ($Co(NH_2)_2$), a chemical fertilizer, was selected as a anesthetic, and its optimal concentration and sea water temperature for exfoliation of Haliotis discus were determined in order to develop an exfoliation technique which is more economical and effective. A 97% cumulated exfoliation rate was observed within 3 min at all temperatures observed when the concentration rate of urea was 9∼15%. This range of urea concentration can be ideal for both exfoliation and recovery. Also it was found that the higher concentration of urea and temperature the higher exfoliation rate, however, these conditions reduced the recovery rates of the animals tested. These results could indicate that urea is a good tool for exfoliation of various species of young abalones, and urea could substitute for all techniques and anesthetics methods currently available for abalone exfoliation.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.16-25
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• 2004

Theoretical analysis for predicting the heat transport limitation of a copper powder sintered wick heat pipe was performed. The heat pipe diameter was 8mm and water was used for working fluid. The particle diameter was classified by 5 different meshes, and each capillary pressures and heat transport limitations. thermal resistances were analyzed according to the operating temperatures, wick thicknesses and inclination angles, based on the effective capillary radius($r_c$), porosity($\varepsilon$), Permeability (K). The wick capillary limitation was increased according as the particle diameter and the wick thickness and the operating temperature were increased. As the porosity and the capillary radius were larger. then the heat transport limitation was higher. The thermal resistance was greatly increased according as the wick thickness was increased.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.163-170
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• 1996

Cellulose fibers, being fairly strong and stiff as well as cheap and plentiful with low energy demand during manufacture, are strong contenders for the reinforcement of cement-based materials. Cellulose fiber-cement composites, generally manufactured by slurry-dewatering procedure, can find applications in the production of flat and corrugated cement sheets and many other thin-sheet cement products. This paper presents the results of an experimental study concerned with the effects of fiber content and moisture conditions on the flexural performance of these composites. An effort was also made to study the effect of pozzolanic admixtures on the flexural performance in different moisture conditions. The test results obtained were analyzed statistically using the analysis of variance in order to derive reliable conclusions. The results generated in this study were indicative of significant effects of fiber content and moisture condition of flexural performance. There is a tendency in flexural strength to increase in increase in fiber content up to 8%: flexural toughness values continue to increase even at higher fiber contents. Moisture content has a significant effect on the flexural performance. There is a tendency in flexural strength to decrease and flexural toughness to increase with increasing moisture content Composites incorporating pozzolans showed an increase in the flexural strength while slightly reducing the flexural toughness and were sensitive to variations in moisture content.

• Journal of KIISE
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• v.42 no.5
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• pp.566-572
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• 2015

We proposed a novel energy optimization technique for smartphone GPUs, more aggressively lowering the GPU frequency while obtaining higher energy efficiency with a negligible negative impact on the GPU performance. In order to achieve the Quality of Service (QoS) specified by the smartphone application, the proposed optimization technique employed the minimal acceptable GPU frequency based on average Frames per Second (FPS) for each GPU frequency level. Our experimental results on a smartphone development board showed that the proposed technique can reduce the GPU energy consumption by up to 23% over the default DVFS algorithm with only a 0.45 frame drop.

• Korea journal of population studies
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• v.13 no.1
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• pp.51-80
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• 1990

한국의 사망력은 높은 수준의 성별 사망력 차이와 중년 남성의 급격한 사망력 상승을 그 구조적 특성으로 하고 있는데, 이러한 한국인 사망력 구조의 특이성은 직접적으로는 사망원인의 성별, 년령별 차별적 역활에 기인하며 간접적으로는 이들 원인의 차별성을 초래하는것으로 추정되는 경제개발기간동안의 사회, 경제 및 공공정책상의 변화 및 생활습관의 차이에서 기인된다고 보아진다. 본 연구에서는 이들 차이를 결과짓는 여러 요인들을 중심으로 한국인의 사망력 구조상에서 나타난 년령별 및 성별특성을 분석하는데 그 주요점을 두었다. 1985년 경제기획원 조사통계과에 의해 집계된 사망원인통계자료는를 활용하여 한국인의 사망력 구조의 특성을 사망원인과 관련시켜 연구분석한 결과는 다음과 같이 종합될수 있다. 첫째, 40대 이후 남성의 높은 사망력에 의거한 요인들은 뇌혈관질환, 고혈압성질환, 암질환 및 기지 심질환 및 간의 악성신생물 순으로 중요하게 나타났다. 둘째, 0세에서의 남녀간의 기득개념의 차이는 차이는 초년 또는 청년층에서의 남녀간의 사망력 차이에서 보다는 40대 이상의 중장년층에서의 남녀간의 사망력 차이에서 비롯되었으며, 뇌혈관 질환, 악성간질환 및 고혈압성 질환, 간의 악성 신생물,및 기타 심질환 및 간의 악성 신생물 질환들이 중장년층에서의 남녀간의 사망력 차이를 결정하는데 주역활을 하고 있는 것으로 나타났다. 세째, 위의 년령간의 및 남녀간의 사망력 수준의 차이를 결정짓는 주요한 사회적 간접요인들로는 첫째, 사회.경제개발과 함께 이어 병행되어온 보건정책들이 즈로 어린이 또는 여성에 편향된 결과 였으며, 둘째,환경적 요소로서 중년 남성들의 Social stress, 운동부족과 관련된 질병들과 공해, 먼지, 유해화학물 가스 등 산업재회와 관련된 질병들에 의한 사망률이 높으며, 세째, 행위적 요소로서 음주와 흡연과 관련된 질병들에 의한 중년 남성의 사망률이 높은것들로 요약될수 있다. 중년 남성의 높은 사망률은 기술적,사회적 경험이 축적된 노동력의 상실로서 국가적 손실이 크며, 고 년령층 인구의 구조적 측면에서도 성의 불균등을 초래하여 미혼 여성의 증가등 사회적인 기반문제의 주요한 요인이 되므로서 그 중요성은 지대하다고 할수 있겠다. 그러므로 이 문제는 국가적 사회적 차원에서 해결이 시급하며 그 해결책으로는 지금 까지 도외시 되어 왔던 중년 남성의 건강을 위한 프로젝트의 실지와 함께 이들에게 노출되어 왔던 운동 부족, 사회적 스트레스 및 산업재회의 해소 내지 제거에 대한 방안들이 연구 되어야 하겠다. 한편 음주 및 흡연등의 개인행위적 습관의 개선을 위한 사회 계몽활동의 추진 및 건전한 스트레스 해결책의 개발이 중요하다고 하겠다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.352-356
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• 2012

본 연구는 최근 우리나라 4대강 중 한강의 기후변화로 인한 온도, 상대습도, 강우량의 관측자료를 통해 과거와 최근의 변동특성에 대해서 파악하고자 하였다. 이를 위해 기상청의 관측자료를 활용하였으며 한강의 상, 중, 하류로 나눠서 3개 지점에 대해 선정하였다. 선정 기준은 인위적인 영향을 많이 받는 도시지역을 제외한 도서 지역에 위치한 관측소를 기준으로 선정하였다. 분석을 실시한 항목으로는 최고, 최저, 평균기온 및 상대습도, 연강우량, 일 최고 강우량, 강우 집중률이 있으며 강우 집중률은 강우량에 의한 강우강도의 변동 특성을 파악하기 위해 분석하였다. 과거(~1994)와 최근(1995~2011)의 변동성을 파악하기 위해 각 항목별로 비모수적 검정을 실시하고, 상위 10개를 선정한 자료를 이용하여 분석하였다. 비모수적 검정으로는 Mann-Kendall, Hotelling-Pabst, Sen's Trend Test를 이용하였고, 표준정규변량을 통해 과거와 최근의 경향성을 비교하였다. 연구 지점 중 양평의 평균 기온은 상위 10개 중 9개가 최근 자료에서 선정되었고 경향성의 유의수준도 더 높게 나타났다. 최저 상대습도는 과거에 비해 최근에 더 높은 유의수준의 하강하는 경향성을 가지는 것으로 나타나, 기후변화로 인한 지구온난화가 진행되고 있다는 것을 보여주고 있다. 연강수량은 최근 자료에 상위 8개가 나타났고, 표준정규변량 또한 높은 유의수준을 가지며 증가하는 것으로 나타났다. 일 최고 강수량, 강우집중률 또한 상위 10개 관측자료 중 1995년 이후 7개가 관측되었고, 이는 강우강도가 증가하는 것으로 판단할 수 있다. 상대습도의 경우 평균 및 최소 상대습도에서 2개가 관측 되어 기온은 상승하고 강우는 집중되는 반면 상대습도는 온도의 영향 이외에도 낮아지는 경향을 보여 오난해지는 가운데 건조해지는 경향을 보임을 알 수 있었다.

• Journal of The Geomorphological Association of Korea
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• v.15 no.2
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• pp.55-65
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• 2008

In order to examine the runoff characteristics of scoria cones in Jeju Island, hydrological observations were conducted in the experimental basin (5.1 ha) of Eoseungsaeng-oreum which has been predominantly covered with Carpinus laxiflora and Quercus serrata. Although runoff has continuously occurred during the observed period, the baseflow gradually increased from April and decreased from October. The peak flow approximately corresponded to every rainfall events except for the rainfall events which has slight total precipitation and no previous precipitation. The experimental basin shows flash runoff response and short lag time; the mean lag time is 35.8 minutes. Although the runoff ratio of quick flow is proportional to total precipitation, the increasing rate is low and the maximum runoff ratio is 24.7%. In addition, the runoff ratio is less than 1% in 68.3% of the rainfall events, suggesting that the portion of quick flow to total precipitation is low. The rainfall events with relatively long event time demonstrated a secondary peak generated by translatory flow. The runoff characteristics seem to be related to local impermeable beds in the experimental basin.