• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.112-112
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• 2022

본 연구에서는 2005-2020년 용담댐의 운영방식이 기후변화에 얼마나 취약한 지 홍수위험과 이수 안전도 지표를 중심으로 평가하였다. 유입량 모의를 위해 GR6J 강우-유출 모형을 사용했고, 댐 운영룰 추출을 위해 Random Forests 모형을 관측자료에 적합시켰다. 294개의 추계학적 기후스트레스 시계열을 GR6J 모형에 입력해 일유입량을 모의한 후 Random Forests 모형으로 방류량과 저수량을 추정하여 연최대일방류량과 공급신뢰도를 분석하였다. 공급신뢰도는 평균강수량 변화에 주로 영향을 받는 것으로 나타났지만 연최대방류량은 평균강수량과 강수변동성 변화에 모두 민감하게 반응하는 것을 알 수 있었다. 2021-2040년 용담댐 저수량은 평균강수량 증가로 인해 공급신뢰도는 과도하게 상승할 것으로 전망되었다. 하지만 강수변동성 증가 인해 20년 빈도 연최대방류량은 가파르게 상승해 댐 하류지역의 홍수위험은 더 가중될 것으로 전망되었다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.62-74
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• 2020

Although the government and local governments devote efforts to activate bicycles, they only access to the supply infrastructure such as bike lanes and the public bicycle rental service centers without considering the measures to overcome the geographical constraints of slope. Therefore, this study constructs bicyclist's energy consumption estimation model through experimental methods of slope gradient and heart rate measurement and suggest the bicycle route choice model which could minimize the energy by the slope gradient. After calculating the RMSE of the estimated energy consumption by applying this model to the simulation section, it is confirmed to be 41% better than the model which does not reflect slope gradient. The results of this study are expected to be applied to the bicycle infrastructure planning that considers both longitude and transverse of bike lanes and the algorithm of bicycle route guidance system in the future.

• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.193-198
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• 2013

The horseback riding simulator, an exercise training machine providing a simplified horse riding motion has been developed for aiming at healthcare. The purpose of this study was to estimate the energy expenditure without measuring bio-signals using the simulator. The test protocol was consisted of increase up to maximal intensity(Motion 9) and decrease down to minimal intensity(Motion 4) during 25 minutes, and energy expenditure was measured by portable cardiopulmonary exercise testing analyzer. There were significant differences in energy expenditure according to each riding motion. The result will be able to estimate energy expenditure using motion level, exercise time, age and gender during the riding.

• Journal of Energy Engineering
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• v.28 no.1
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• pp.65-72
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• 2019

The Korean government is aiming to produce 20% of the electricity using renewable energy sources by 2030. Ocean renewable energy sources which are abundant in South Korea can do an important role to achieve the goal. This paper introduces a tidal current energy converter utilizing flow induced vibrations which can efficiently work even in the currents slower than 1.0m/s and suggests optimal designs of the tidal energy converter based on speeds of the tidal currents in seven different coastal regions in South Korea. Moreover, the theoretical annual energy production by the tidal converter is estimated at theses costal areas. The total amount of the annual energy production by the tidal energy converter is predicted as 221.77 TWh which is equivalent to 42.3% of the electric consumption of South Korea in 2013. The result shows that the tidal current energy converter can be an important role to achieve the goal of the Korean government.

• Plant Journal
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• v.12 no.2
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• pp.4-8
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• 2016

환경보전은 전 인류의 노력이 함께 투입되어야 하며 그 투입 노력의 양은 공학적 관점에서 결정되어야 할 것이다. 탄소배출권 관점에서는 탄소 배출 사업자만이 환경보전에 노력해야하며 그 노력의 양은 경제학적 관점의 탄소 배출량이다. 본 연구에서 제안하고 있는 무용에너지 배출권 관점에서는 모든 인류가 환경보전에 노력해야 하며 그 노력의 양은 열역학적으로 계산되는 무용에너지 배출량이다. 본 제안이 환경보전에 이바지될 수 있기를 희망한다.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.21-26
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• 2009

Purpose: The aim of this study was to examine the dose-related effect of extracorporeal shock wave therapy (ESWT) for lateral epicondylitis. Materials and methods: Thirty patients with refractory lateral epicondylitis despite conservative treatment for 6 months were enrolled in this study. The patients were divided randomly into a low- and high-energy group. All patients were treated 3 times with ESWT with an interval of 1 week in a double blinded manner. The mean energy level in the low- and high-energy group was $0.12 mJ/mm^2$ and $0.24 mJ/mm^2$, respectively. The upper extremity functional scales and Mayo elbow scores were measured prospectively at the baseline, 1, 3 and 6 months after ESWT. Results: Significant clinical improvement was observed in both groups after ESWT. The high-energy group showed better pain improvement at 6 months after ESWT (p=0.019). The effect of ESWT was dominant between 1 and 6 months after ESWT than within 1 month. Conclusion: ESWT for lateral epicondylitis demonstrated showed good results regardless of the energy dose. However, a high-energy level was more effective in pain improvement after 6 months of treatment.

• Feed Journal
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• v.2 no.9
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• pp.104-107
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• 2004

하절기 사육환경 온도가 상승함에 따라 젖소가 받는 스트레스로 인한 생산성 저하는 저능력우 보다 고능력우에서 증가하게 되는데, 이는 높은 산유량을 유지하는데 필요한 기초 에너지 소모가 증가하여 체온이 증가하기 때문이다. 또한 고능력우들은 높은 산유량을 유지하기 위하여 더 많은 에너지와 영양소를 섭취하여야만 하는데 고온스트레스로 인하여 사료 섭취량이 감소, 에너지 부족현상을 다른 젖소들보다 더 심각하게 겪으므로 대사성 질병 발생이나 번식능력의 저하가 현저히 나타나기 때문이다(외기의 적정온도 : 4~24℃). (중략)

• Information and Communications Magazine
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• v.31 no.7
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• pp.66-72
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• 2014

최근 스마트폰의 보급으로 인해 모바일 데이터 요구량이 급속하게 증가함에 따라 효율적인 기지국 운영이 중요시되고 있다. 현재 기지국은 단말들의 트래픽 요구량에 관계없이 항상 켜져 있지만, 트래픽 요구량이 비교적 낮은 경우 불필요한 기지국의 전원을 오프함으로써 상당한 에너지를 절약할 수 있음이 밝혀졌다. 본고에서는 매크로셀, 릴레이, 소형셀, 무선랜 등 다양한 종류의 네트워크가 혼재하는 환경에서 기지국의 전원을 켜고 끔으로써 에너지를 절약하는 기술의 현황을 알아본다.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.841-855
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• 2018

The purpose of this study is to estimate the available potential heat source for heat pump in the district heating supply area in the city. Unused energy potentials were estimated and integrated based on open source based data. In particular, geographical spatial analysis of recoverable heat energy density and heat demand in the heat source area of large retailers and public sauna facilities in the DH network located in the southern part of the metropolitan area (Pyeongtaek-si) was conducted. As a result of the study, the DH network area had a total potential energy of 1,741.7 toe/year for the two heat sources of large retailers and public saunas. It is estimated that 1,006.9 toe/year, which is 57.8% of the total, can be linked to the district heating. The large retailers showed a positive correlation with the floor area and energy use of 0.4937. The recoverable energy intensity was estimated to be $0.0017toe/m^2$ per unit area and $0.0069tCO_2/m^2$ for greenhouse gas emissions. In addition, public saunas were analyzed by comparing the empirical case with the theoretical calculation, and it was estimated that energy conservation estimate of 80% was $0.0315toe/m^2$ per bath area and $0.1183tCO_2/m^2$ for greenhouse gas emissions. The total potential energy amount of this area was positively correlated with the heat demand of apartment house by administrative district, and it was confirmed that it had a relatively high potential energy especially in traffic and commercial center.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.1
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• pp.146-153
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• 2010

The physics theory applied to the elliptical health trainers can be a good example in engineering education. From the point of view of the physics education the measurement of mechanical and thermal energy expenditure in elliptical trainers can be related to the muscle activity, quantity of motion, and metabolic cost. We realized that the low speed training is effective for high basal metabolism due to increasing the muscle activity even if the high speed training is effective for training down. Elliptical Trainer may provide an effective oxygen exhaustion and thus effective training down. However, the metabolic cost does not have much relation to the amount of training under the high speed of trainer.