• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.51-59
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• 2018

Despite the advantages of energy arbitrage using energy storage systems (ESSs), the high cost of ESSs has not attracted storage owners for the arbitrage. However, as the costs of ESS have decreased and the price volatility of the electricity market has increased, many studies have been conducted on energy arbitrage using ESSs. In this study, the existing two-period model is modified in consideration of the ESS cost and risk-free contracts. Optimal investment strategies that maximize the sum of external effects caused by price changes and arbitrage profits are formulated by market participants. The optimal amounts of ESS investment for three types of investors in three different market structures are determined with game theory, and strategies in the form of the mixed-complementarity problem are solved by using the PATH solver of GAMS. Results show that when all market participants can participate in investment simultaneously, only customers invest in ESSs, which means that customers can obtain market power by operating their ESSs. Attracting other types of ESS investors, such as merchant storage owners and producers, to mitigate market power can be achieved by increasing risk-free contracts.

• Physical Therapy Rehabilitation Science
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• 제3권2호
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• pp.142-147
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• 2014

Objective: This study aims to investigate high energy and low energy extracorporeal shockwave therapy (ESWT) and which one is more effective for shoulder pain. Design: Single blind randomized controlled trial. Methods: Fifty two subjects with upper trapezius (UT) trigger point (TrP) participated in this study. They were allocated to high energy (n=26) and low energy group (n=26). This study applies ESWT and investigates the changes of pressure pain threshold (PPT) and visual analogue scale (VAS). The high and low energy groups received focused piezo electric type ESWT 4 Hz, 1,000 pulses and 0.351 and $0.092mJ/mm^2$ respectively. Outcome measures of PPT and pain was measured by algometer and pain VAS. These measurements were performed before and after treatment. Results: The PPT value was significantly increased in both groups after treatment (p<0.05) and VAS scores were significantly decreased after treatment in both groups (p<0.05). However, there were no significant differences between groups. Conclusions: ESWT is an effective treatment for the application of the UT TrP. Although there were significant effects of extracorporeal shock wave therapy on PPT and VAS scores, there were no signficant differences between high and low energy extracorporeal shock wave therapy.

• KIEE International Transactions on Power Engineering
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• 제5A권4호
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• pp.396-402
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• 2005

In an electricity market with imperfect competition, participants devise bidding plans and transaction strategies to maximize their own profits. The market price and the quantity are concerned with the operation reserve as well as the bidding system and demand curves in an electricity market. This paper presents a market model combined by an energy market and an operating reserve market. The competition of the generation producers in the combined market is formulated as a gaming of selecting bid parameters such as intersections and slopes in bid functions. The Nash Equilibrium (NE) is analyzed by using bi-level optimization; maximization of Social Welfare (SW) and maximization of the producers' profits.

• 대한전기학회논문지:전력기술부문A
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• 제50권8호
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• pp.379-387
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• 2001

This paper shows that we can make simple modifications to an existing optimal power flow(OPF) algorithm that minimizes generation costs in order to solve the maximization of social welfare objective of the OPF in a competitive electric power market. We have illustrated the potential for the use of OPF in light of the marked impacts on nodal prices and generation/demand allocation levels among competing suppliers. This paper can provide all market players with the transparent information that ensures sufficient control over producers and consumers in case of economic of secure operation with transmission line outage while maximizing the sum of participants social benefit of participating in the electricity energy market.

• 생명과학회지
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• 제32권9호
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• pp.706-711
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• 2022

육계는 도축 전에 다양한 스트레스에 노출되며, 스트레스는 육계의 복지 수준과 도체 품질에 영향을 미친다. 따라서 농장의 사육 시스템은 육계의 스트레스를 감소시키고 동물복지를 향상시키기 위해서 매우 중요하다. 본 연구는 일반농장과 동물복지농장의 차이를 평가하고 스트레스를 측정하기 위한 지표로 feather corticosterone를 제시하기 위해 수행되었다. 육계의 스트레스 수준과 에너지 대사를 나타내는 HSP 70, glycogen, L-lactate와 함께 feather과 serum에서 추출한 corticosterone를 분석하기 위해 도축장에서 28일 된 육계의 샘플(혈액, 깃털, 근육)을 수집했다. Feather corticosterone은 일반농장군이 복지농장군보다 유의하게 (p<0.01) 높았으나 serum corticosterone에서는 유의성이 없었다. HSP70은 muscle과 feather에서 유의적인 차이가 없었다. Glycogen은 일반농장군이 복지농장군보다 유의하게 높았으나(p<0.01), L-lactate에서는 차이가 없었다. 본 연구 결과는 feather corticosterone 이 일반농장과 동물복지농장의 차이를 평가하고 장기간의 스트레스를 평가할 수 있는 지표임을 시사한다.

• 한국융합학회논문지
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• 제12권12호
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• pp.331-338
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• 2021

본 연구는 에너지바우처제도가 서비스 이용자 가구의 소비·지출에 미친 영향을 파악하고자 하였다. 자료는 한국복지패널 10차년도(2015년)와 15차년도(2020년)을 이용하였다. 연구대상은 서비스를 이용한 실험군과 이용하지 않은 통제군으로 구성하였다. 집단간의 특성차이는 카이제곱검정 및 t-test를 이용하였으며, 다중이중차이회귀분석을 통해 소비·지출에 대한 영향을 파악하였다. 연구결과 에너지바우처제도 이용자 가구의 총생활비(𝛽=-5.37)와 보건의료비(𝛽=-2.37)는 감소하였으며, 기본비(𝛽=2.51)와 교육비(𝛽=0.54)는 증가하였다. 보건의료비와 기본비는 제도 효과에 통계적으로 유의한 차이가 있었다. 따라서 제도 효과를 증대시키기 위해서는 급여수준을 확대하고 급여대상자의 자격기준을 완화하는 제도개선이 요구된다.

• 사물인터넷융복합논문지
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• 제7권2호
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• pp.1-6
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• 2021

최근 세계적인 급속한 산업발달과 경제성장으로 한정된 공간에 많은 사람들이 모여 살면서 급속한 도시화가 진행되고 있으며 2050년 세계적 도시 인구비율은 70% 이상으로 추정되고 있다. 급격한 도시화로 인해 재난안전, 대기오염, 수질오염, 에너지 부족, 질병, 범죄, 교통 등 다양한 도시문제 해결을 위해 정부주도의 스마트시티 모델들이 개발 및 도입되고 있다. 하지만 사회간접자본 형태의 사업으로 진행되고 있기 때문에 공공주택의 ICT 기술은 민간시장의 스마트 가전 위주로 개발되어 공공주택 주민을 위한 공공안전, 생활환경, 생활복지, 에너지관리 등의 서비스가 개발되어 주민이 체감할 수 있는 마이크로 스마트 시티 사업이 필요하다. 본 논문에서는 4차 산업혁명시대 스마트 시티를 위한 공공주택의 스마트 플랫폼 화 모델을 설계하고 실증방안을 제시하므로서 국내 스마트시티 분야에 활용할 수 있도록 하였다.

• 한국수소및신에너지학회논문집
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• 제26권5호
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• pp.453-462
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• 2015

In this study, a methodology is investigated for the development of social responsibility program employed by major domestic companies under social pressure. It is true, however, that its infancy in history and lack of experience makes it difficult to run novel programs for the companies on their own and it naturally leads to copying and/or slight modification of what others do. Utilizing widely accepted SWOT analysis, stakeholders analysis and PDCA Cycle, a methodology for the successful programs with sustainability is proposed by reflecting business nature and strategic direction. Three real cases are analyzed. In addition, relationship and position with social welfare organizations is elucidated.

• 대한지역사회영양학회지
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• 제17권6호
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• pp.714-723
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• 2012

The aim of this study was to compare nutrient intakes, serum hormones (leptin, adiponectin, insulin), salivary cortisol and ${\alpha}$-amylase of middle-aged women by the percentage of body fat (% fat). Subjects were assigned to 3 groups by body fat (%) group I (27.5%), group II (32.5%), group III (37.7%). WHR of group II (0.97) was significantly higher than of group I, III (0.95) (p < 0.05). Nutrient intakes were not different among 3 groups. Serum leptin levels of group III ($16.53{\mu}g/ml$) were higher than in group I ($10.07{\mu}g/ml$), group II ($12.24{\mu}g/ml$) (p < 0.05). Salivary cortisol levels of group II ($0.39{\mu}g/dl$) were higher than in group I ($0.17{\mu}g/dl$) and group III ($0.15{\mu}g/dl$) (p < 0.05). Adiponectin concentrations were negatively correlated with TAS (r = -0.29) and positively correlated with HDL cholesterol (r = 0.27). Insulin levels were negatively correlated with total cholesterol (r = -0.33), Zn intake (r = -0.31) and positively correlated with WHR (r = 0.31). The overall anthropometric indices showed positive relations with leptin levels. Salivary cortisol levels were positively corelated with WHR (r = 0.28), total cholesterol (r = 0.31), MDA (r = 0.29) and intakes of SFA (r = 0.35) and MUFA (r = 0.3). Salivary amylase levels were positively correlated with overall nutrient intakes (energy, CHO, fat, cholesterol. Fe, SFA, MUFA, Zn, Na, vitamin $B_2$, r = 0.24-0.5) and was negatively correlated with HDL cholesterol (r = -0.34). These results suggested that 1) WHR would be a helpful index in the assessment of metabolic risk diseases. 2) Understanding of individual stress exposure should be considered in developing strategies for prevention and treatment of obesity.

• 한국환경과학회지
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• 제24권8호
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• pp.1003-1013
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• 2015

The Ministry of Trade, Industry and Energy is now placing emphasis on the importance of a new and renewable energy resource map service as an essential means of promoting the dissemination and adoption of renewable energy and other related industrial activities. To raise satisfaction with the new and renewable energy resource map service and promote its utilization, a survey was conducted on a sample group with an academic research background, i.e. employees of the Korea Institute of Energy Research (KIER) who have a thorough understanding of the technological concepts behind the new and renewable energy resource map. Statistical analysis of the survey results showed a high level of overall satisfaction with the web service for the new and renewable energy resource map. Therefore, it was concluded that the development of practical contents rather than the enhancement of web service convenience is required. A statistically significant trend was also observed whereby, the longer the professional career of the survey respondents, the greater their perception and utilization of, and satisfaction with, the enhanced service, which indicates that their level of understanding and utilization of technological concepts corresponds to their research experience record. In addition, the results obtained from the questionnaires regarding the evaluation of the utilization value of the resource map service indicated that use of the service was equally high in terms of political, business and academic applications. The results confirmed the need to develop multidimensional resource map contents that can be applied to as many fields as possible, rather than focusing on a specific terrain.