• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.1-8
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• 2016

Current sensors are used widely in the fields of current control, monitoring, and measuring. They have become more popular with the increasing demand for smart grids in a power network, generation of renewable energy, electric cars, and hybrid cars. Although open loop Hall effect current sensors have merits, such as low cost, small size, and weight, they have low accuracy. This paper describes the design and fabrication of a 300A open loop current sensor that has high accuracy and temperature performance. The core of the current sensor was calculated numerically and the signal conditioning circuits were designed using circuit analysis software. The characteristics of the manufactured open loop current sensor of 300 A class was measured at currents up to 300 A. According to the test of the current sensor, the accuracy error and linearity error were 0.75% and 0.19%, respectively. When the temperature compensation was carried out with the relevant circuit, the temperature coefficients were less than $0.012%/^{\circ}C$ at temperatures between $-25^{\circ}C$ and $85^{\circ}C$.

• Journal of the HCI Society of Korea
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• v.12 no.4
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• pp.65-73
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• 2017

While electricity demand is generally increasing, stably controlling supply is becoming a serious challenge because renewable energies are becoming popular and often their productions are dependent on the weather. The 'demand response' programs can be used to complement the problems of renewable energies, and therefore their role is becoming increasingly important. This study provides an analysis of a demand response pilot that was conducted in Korea. The study first focused on questionnaire surveys and in-depth interviews, and the data was used to perform a Technology Acceptance Model (TAM) analysis. The goal of the pilot was to have the residential users reduce their power consumptions when an energy reduction mission is issued during peak load hours. The experimental subjects consisted of two groups with different characteristics. Subjects in group A obtained smart meters as an optional function of IoT platform service provided by a mobile service company, and received a charge deduction as their compensation. Subjects in group B either voluntarily purchased smart meters as individuals or received them by participating in an energy self-sufficient village program that was run by a local government, and were entitled to a donation as their compensation. With the analysis, group A was found to fit the extended technology acceptance model that includes perceived playfulness in addition to perceived ease of use and perceived usefulness. On the contrary, group B failed to fit the model well, but perceived usefulness was found to be relatively more important compared to group A. The results indicate that the residential energy groups' behavior changes are dependent on each group's characteristics, and group-specific DR design should be considered to improve the effectiveness of DR.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2002.05a
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• pp.3-42
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• 2002

21세기에는 인구의 폭발적 증가와 함께 가속화된 산업화로 말미암아 경지 면적은 줄고 농업 환경은 더욱 피폐해질 것으로 예상된다. 지금도 이미 화석 에너지원의 고갈로 대체 에너지 개발이 시급히 요구되고 있으며, 지구의 자연 환경 보존 목소리도 그 어느 때 보다 높다. 한마디로 식량, 에너지, 환경 문제가 새 세기에 우리가 시급히 해결해야할 과제로 주어져 있다. 이에 과학계에서는 식량 및 대체 에너지원의 공급을 증대시키고 환경을 보존할 수 있는 보편적인 수단으로 환경 친화적 유전자 변형 (GM)작물의 활용이 제시되고있다. 따라서 선진국들은 이의 기반이 되는 식물유전체 연구에 대규모 투자를 아끼지 않고 있으며, 이를 이 용한 식물 생명공학산업을 국가 전략 산업으로 집중 육성하고 있다. GM작물 제조 기술은 유용 유전자의 발굴 및 재조합, 식물세포로의 이식 및 재분화를 통한 완전한 식물체 재생, 이를 품종으로 실용화하는 단계로 구성되어 있다. GM작물은 1983년 항생제 저항성 담배가 개발된 것을 시점으로 하여, 1994년에는 연화지 연 토마토 Flaver Saver이후 지금까지 개발 실용화된 작물은 제초제 저항성 콩, 카놀라, 목화, 그리고 해충 저항성 옥수수 등이 있으며,2001년까지 세계적으로 상품화 승인을 얻은 경우는 15 작물 68품종에 이른다. 2001년 경우 GM작물 종자시장은 약 30억 달러에 달하고 있으며, 미국, 아르헨티나, 캐나다 등 세계적으로 52.6백만 ha에 이르는 면적에서 재배되었다. 그러나 GM농산물의 식품 및 환경 안전성에 대한 의구심이 일기 시작하였고, 따라서 이의 생산 및 소비에 대한 전반적 인 문제가 뜨거운 쟁점으로 부각되기도 하였다. 이 에 각국 정부는 객관적 인 안전성을 확보하기 위한 제도적인 장치를 마련하고 있으며, 아울러 과학기술자들은 더욱 안전한 형질전환 기술 개발을 도모하고 있다. 다음 세대의 GM작물은 단순한 제초제 및 병해충 저항성을 넘어서서 특정 영양 또는 건강기능성을 향상시켜 부가가치를 증가시킨 신품종 맞춤작물이 지속적으로 개발 상업화될 것이다. 따라서 고유성을 가진 유용 유전자의 대량 확보 여부가 산업적 경쟁력을 결정하게 될 것이다. 지금까지 개별 유전자 중심으로 이루어지던 유용 유전자 발굴 작업은 유전체학의 출현으로 규모가 대량화되고 그 효율이 증진되었다. 따라서 진 각국은 유용 유전자 발굴에 국가적 차원의 역량을 집중하고 있다. 그러나 우리나라는 정부와 민간의 소규모 지원으로 근근히 기술 습득 차원에 머물러 왔으며, 산업적 경쟁력의 무기가 될 고유한 유용 유전자와 형질전환 기술이 거의 없는 어려운 상황에 놓여 있다. 최근 정부가 시작한 생명공학 분야 대규모 연구지원 사업 기대를 모아 보며 이 분야 과학기술자들의 노력을 촉구한다.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.141-147
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• 2019

Recently, the biggest issue in the electricity industry is the increase in renewable energy, and various technologies are being developed to ensure the capacity of the power system. In addition, super-grids linking power systems are being pushed to utilize eco-friendly energy between countries and regions worldwide. The HVDC transmission technology is required to link the power network between regions with different characteristics of the power system such as frequency and voltage. Until now, Korea has applied HVDC transmission technology that connects mainland and Jeju Island with submarine cables. But, the HVDC transmission technology is still developing for long-distance high-capacity power transmission from power parks on the east coast to load-tight areas near the metropolitan area. Considering the high population density and mountainous domestic environment, it is pushing for commercialization of the design technology of the ${\pm}500kV$ Double Bipole with metallic return wire transmission line to transmit large-scale power of 8 GW using minimal right of ways. In this paper, the insulation characteristics were studied for the design of double-bipole transmission tower with metallic return wire, which is the first time in the world. And the air insulation characteristics resistant to the various overvoltage phenomena occurring on transmission lines were verified through a full-scale impulse voltage test.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.1
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• pp.1-12
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• 2023

Along with the growing interest in renewable energy development, Korea's west coast is one of the favorable regions for tidal power. Tidal power using tidal barrages that work like hydroelectric dams is a representative method of tidal power through long-term operation, but the promotion of tidal power projects is being delayed or stopped due to impacts on ecological changes, reproduction, water column processes and hydrology. In order to reduce the high construction cost and environmental cost problems caused by tidal power using tidal barrages, in this study, field experiments were conducted to develop and verify the performance of tidal power generation devices applicable to sea areas where dykes are already installed. As a result of conducting five cases of experiments using two water tanks, pipe lines, open channels, and water turbine and generator, the possibility of developing a power generation system capable of generating more than 10 kW output and more than 60% efficiency were confirmed. The results of this study can be used for small-scale tidal power by utilizing the existing dykes of the west coast.