• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1125-1134
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• 2013

Small cells such as pico or femto cells are promising as a solution to cope with higher traffic explosion and the large number of users. However, the users within small cells are likely to suffer severe inter-cell interference (ICI) from neighboring base stations (BSs). To tackle this, several papers suggest BS transmit power on/off control algorithms which increase edge user throughput. However, these algorithms require centralized coordinator and have high computational complexity. This paper makes a contribution towards presenting fully distributed and low complex joint BS on/off control and user scheduling algorithm (FDA) by selecting on/off pattern of BSs. Throughput the extensive simulations, we verify the performance of our algorithm as follows: (i) Our FDA provides better throughput performance of cell edge users by 170% than the algorithm without the ICI management. (ii) Our FDA catches up with the performance of optimal algorithm by 88-96% in geometric average throughput and sufficiently small gap in edge user throughput.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.629-639
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• 2014

This paper deals with an alternative multi-functional structures by using grid-stiffened composite structure with excellent bending stiffness and lightweight characteristics which is capable of easy embedding of electrical/electronic circuitry into structure. The enhancement of thermal conduction capability is made by the application of pitch-based carbon fiber. The lightweight radiation spot shielding technique is also proposed for multi-functional structures without conventional housing and the effectiveness of selective radiation shielding is validated through the proton irradiation test.

• Journal of Energy Engineering
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• v.26 no.2
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• pp.64-72
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• 2017

The performance analysis of the 70 W class LED lighting system suitable for the Middle East environment was performed using the lumped parameter model. The LED light is composed of a heating substrate, a heat pipe, and a heat sink. We divided the LED lights into four objects and applied energy equilibrium to each of them to establish four lumped nonlinear differential equations. The solution of the simultaneous equations was obtained by the Runge-Kutta method. Convective heat transfer coefficients of the lumped model were obtained by multidimensional CFD analysis. As a result of comparison with experiment, it was found that the heating substrate had an error of $1.5^{\circ}C$ and the upper heat sink had an error of $1.8^{\circ}C$ and the relative error was about 0.6 %. Using this model, temperature distribution analysis was performed for normal operating conditions with an ambient temperature of $55^{\circ}C$, with sunlight only, with abnormal operating conditions with sunlight, and without an upper heat sink.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.245-256
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• 2007

There are approximately 250,000 organic livestock farming in the world. The total retail value of organic food sales in the world is $ 27 billion. The organic livestock products such as milk, lamb and beef are marketed mostly in Europe and the USA. The market share of organic food is about 2% in total food marketing value of worldwide and of the organic food marketing value, organic livestock products portioned 17% in the USA. The organic livestock products are primarily marketed at Supermarket(Europe), Health and Natural Food store(USA). Concerning international trade, it is very little. But it is increasing among the developed counties of Europe. In the future, the production of organic livestock products will be rapidly increased in South America, Middle East and Oceania, but the growth rate will be limited due to its expensive price, lack of marketing-infra and different regulation system. Most of developed countries drive organic farming policy strongly as the strategic means of rural development, diversifying agriculture system and environmental improvement.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.135-141
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• 2013

Subway in Korea, most of a metropolitan public transport use only worth ten million people a day floating population of wireless communication can be considered HOT SOPT. These three operators' 2G/3G/4G / Wi-Fi / T-DMB frequency and the number of services to co-exist, and the subway train passengers and subway party for operation and management of the communication network is also the co-subway passenger safety and for this service for the effects of mutual interference of whether the verification was necessary. This research and testing different frequency / communication interference between services and testing to determine whether, through the subway authorities and mobile operators in each frequency-specific interaction check and there is no interference to the safety and quality of subway passengers communication services that can be verified as the data was found. The verification methods in the metro area, not just from one region to determine whether the interference with a common verification methods can be applied.

• Environmental and Resource Economics Review
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• v.15 no.5
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• pp.859-884
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• 2006

This study attempts to apply a conjoint analysis, especially using choice experiment, to quantify the economic benefits of health effects(mortality by lung cancer, asthma, acute bronchitis, chronic bronchitis) on air quality improvement in Seoul and Metropolitan area. The yearly willingness to pay for the highest improvement level which is available is estimated as 38,856 won per household. The aggregated value of Seoul and Metropolitan area is measured as 252.8 billion won annually. The quantitative result provided in this study can be usefully employed in policy-making process related to air pollution. Especially, it provides a methodological framework to estimate the benefits for various alternatives in health effects.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1195-1199
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• 2009

Each country has tried to collect and utilize sci-tech information which is the critical factor for the technology innovation of the nation. The national science and technology information center has the main role for finding, acquiring, and utilizing S&T information scattered all over the world. Korea Institute of Science and Technology Information delivers almost 300,000 articles to the users every year. As the quantity of information increases rapidly, its source, its storage media and its delivery method become diverse. This study analyzes the user satisfaction on S&T document delivery service of the national information service center generally. The ultimate aim of this study is to improve the quality of the document delivery service and meet the users' requests in the changeable information circumstance.

• The Korean Publising Journal, Monthly
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• s.244
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• pp.14-15
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• 1998

도서관을 찾는 사람은 늘고 있으나, 읽는 책은 베스트셀러에 한정됐다. <출판저널>이 '독서의 달'을 맞아 전국 도서관 사서들을 대상으로 도서관 이용자의 독서경향에 대해 설문조사한 결과, 교육환경의 개선과 IMF여파로 이용자 수는 증가했으나, 도서구입예산과 독서 프로그램 부족으로 도서관에서 이뤄지는 독서는 문학 등 특정 분야에 편중되고 있다는 사실이 밝혀졌다. 학생들의 대출 건수는 꾸준히 늘어 강화군립도서관만 하더라도 전체 대출의 55%가 학생이다. 다른 도서관도 사정은 같아 학생들이 하교하는 오후 시간대에 가장 이용률이 높다. 최근에는 실직인구가 늘면서 성인 남자의 이용률도 높아졌다. 오미순 사서(해운대도서관)는 "IMF 여파로 취업.창업 관련서의 이용률이 늘고 있으며 그 이용자 대부분은 성인"이라고 밝혔고 성은정 사서(부여도서관) 역시 "IMF사태 이후, 성인 남자들의 이용률이 높다"고 응답했다. 하지만 문제는 도서관이 보유한 책이 베스트셀러에 국한돼 다양한 독서가 이뤄지지 않는다는 점. 조사결과, 이용자들은 <아리랑>, <하늘이여 땅이여>, <남자의 향기>, <토지> 등을 많이 찾는 것으로 집계됐다. 심지어는 로맨스소설이나 무협소설이 청소년들의 읽을거리로 제공되는 실정. 사정은 특수도서관도 마찬가지다. 어린이도서관의 경우, 어린이.성인 모두 문학류를 많이 찾고 점자도서관의 경우, 전체대출 중 80%가 소설류다. 구본일 사서(강화도서관)는 "예산이 부족해 이용자들이 많이 찾는 베스트셀러를 중심으로 구입할 수밖에 없다"고 밝히고 "다양한 책을 갖출 수 있도록 도서구입비 확충이 시급하다"고 주장했다. 또 알맞은 독서 프로그램이 없는 점도 이용자들의 베스트셀러 편중현상에 한몫을 담당했다. 진재호 사서(광주도서관)는 "과거보다 독서생활화가 고조됐지만, 양서를 읽는 독서문화의 부족"을, 김선연 사서(어린이도서관)는 "유아시절부터 성인까지 자연스레 고전을 읽게 하는 제도적 장치의 확충"을 지적했다. 한편 월평균 대출권수는 대도시 지역의 경우 11,000-45,000권, 그 외 지역은 1,600-6,000권, 특수도서관은 어린이도서관이 55,000권, 전화나 우편으로 대출하는 점자도서관이 650권이다. 관내열람만 허용되는 사회과학도서관은 월평균 이용자가 7,676명으로 대학생.대학원생.교수 등이 전체의 68%를 차지한다.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.457-476
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• 2016

This was investigated on the major issues and research trends regarding the heat-treatment of woods through literature reviews. The principal heat-treatment technologies utilized for industrial purposes include the Plato-process (Netherlands), the Retification process (France), the OHT-process (Germany), and the Thermowood Process (Finland). Factors that mainly influence the heat-treatment process are the wood species, process temperature, processing time, and the heating medium (air, steam, vacuum, N2, oil, etc.). Researches on investigating the optimal conditions with these process conditions being the variables stand as the mainstream. Heat-treated woods present dimensional stability improvement, but mass loss and strength reduction, a wide variations for decaying inhibition, and insufficient resistance against mold, wood borer, and termites. For further improvement in respects of durability or resistance to biological degradation, necessity to search for more suitable heat treatment process and processing conditions fit for each wood species has been suggested. Exploiting new ways to utilize heat-treated wood and extending its range of use have been considered to be important matters that need more effort put into for the sustainable and sound environment as well as saving the wood resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.157-164
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• 1996

Dry weight and body fluid osmolarity of embryo, and maternal ovarian fluid and the ovarian inner tissue of the viviparous teleost, Ditrema temmincki, changed considerably during the gestation period. After the complete absorption of the egg yolk, average dry weight of the embryo increased to 373.76 mg, and the range of total length (TL) was from 6.0 to 60.0 mm. Osmolarity of the embryonic body fluid was 796,8 mOsmol/kg with TL 64.0 mm right before parturition. Ovarian outer membrane started to swelling clearly after fertilization, and maximized in March. The swelling of ovigerous folds was maximized in late April. Expansion of blood vessels and increase of hemocytes reached to their maximum right before parturition. The results of this study indicated that these changes are related to the nutritional and environmental adaptation of both the embryo and the maternal body during the gestation period.