• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.425-428
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• 2017

This paper describes a full-wave rectifiers for energy harvesting circuit using a vibrational energy. The designed circuit is applied to the negative voltage converter with the body-bias technique using the Beta-multiplier so that the power efficiency is excellent even at the low voltage, and the comparator is designed as the bulk-driven type. The proposed circuit is designed with $0.35{\mu}m$ CMOS process, and The designed chip occupies $931{\mu}m{\times}785{\mu}m$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.513-520
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• 1991

The objective of experiment was to investigate the effects of seeding rate on forage yield and feed value, and to clarify the optimum seeding rate of rye in middle west area when cultured in paddy field. The field experiment treated with 5 levels of seeding rate was carried out at Yesan area in 1989. The plant height and the number of tillers per m' were increased but the dry matter rate was decreased as seeding rate increased. The fresh and dry weights of rye plant were increased as seeding rate increased. The highest yield was obtained from the harvest of May 15 and 25 in Yesan area. The TDN content and RFV were decreased by the increased seeding rate and delayed cutting date. The highest TDN yield was obtained from the seeding rate of 18kg/l0a and the next highest yield was obtained from the 23kg and 28kg/l0a seeding rate. The content of ENE, NEL, NEM, and NEG was decreased by the increased seeding rate and delayed cutting date. The highest ENE and NEL yields were obtained from the seeding rate of 23kg/l0a and May 15 harvest. The highest NEM and NEG yields were obtained from the seeding rates of 18kg/l0a and May 15 harvest, and of 18-28kg/l0a and May 5 harvest, respectively.

• Journal of the Korean Regional Science Association
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• v.33 no.3
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• pp.49-59
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• 2017

The piezoelectric energy harvester is recently being developed and catching on as a way to achieve low carbon green growth. The practical application of the piezoelectric energy harvester is expected to contribute not only to the reduction of greenhouse gas emissions but also to the improvement of residents' welfare. This paper conducted a cost-benefit analysis for the installation of piezoelectric energy harvester on the highway focusing on its impacts on the public. The results showed that the installation of piezoelectric energy harvester on the gyeongbu highway is economically feasible in that it could increase the social welfare for the residents. Finally, this paper suggests policy direction for the practical use of the piezoelectric energy harvester, based on the results obtained.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.73-74
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• 2015

본 논문에서는 인체의 움직임에서 발생하는 낮은 주파수의 진동 에너지를 전기 에너지로 수확하는 전자기유도 현상 기반의 고효율 에너지 하베스터를 제작하였다. 제안된 하베스터는 기어모듈을 이용하여 사람이 인가하는 직선운동을 회전운동으로 바꾸는 방식으로 동작한다. 회전수를 늘리기 위해서 증속기어모듈을 달아 높은 회전비를 갖게 한다. 그리고 발전부의 자석들은 할바흐 배열을 통해 불필요한 곳의 자속을 최소한으로 하고 필요한 곳의 자속은 최대한으로 하여 높은 효율을 낼 수 있게 하였다. 제작된 전자기 에너지 하베스터의 출력전압은 230.9 mV이며 $18{\Omega}$에서 2.96 mW의 최대 피크 전력을 전달한다.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.377-382
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• 2021

Oriental melon (Cucumis melo L.) is generally cultivated on the ground by creeping culture. A farmer has a higher workload for training stems. This study was conducted to find out a new cultivation of oriental melon to reduce a workload and improve the quality of fruit. There were three treatments for training stem of oriental melon; upward stem growing, downward stem growing, control (creeping stem growing). The results of the plant growth and the net photosynthesis showed higher in upward stem growing. The root activity was higher in downward stem attract. The yield was not significant as 4,055kg/10a in upward stem attract and 3,983kg/10a in downward stem attract. According to the results of the ergonomic agricultural workload evaluation, in the case of the working posture, the working posture of creeping cultivation methods (squatting, bending) showed a higher risk level than the upward and downward cultivation methods. Therefore, it is recommended the upward stem attract of oriental melon is a new cultivation as well as an alternative method for creeping stem attract in terms of improving the plant growth and yield, and reducing the workload.

• Clean Technology
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• v.27 no.3
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• pp.269-274
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• 2021

Bioenergy is generally considered to be one of the options for pursuing carbon neutrality. However, for a period of time, combustion of harvested plant biomass inevitably causes more carbon dioxide in the atmosphere than combustion of fossil fuels. This paper proposes a method that predicts and minimizes the total amount and payback period of this carbon debt. As a case study, a carbon cycle impact assessment was performed for immediate switching of the currently used fossil fuels to biomass. This work points out a fundamental vulnerability in the concept of carbon neutrality. As an action plan for the sustainability of bioenergy, formulas for afforestation proportional to the decrease in the forest area and surplus harvest proportional to the increase in the forest mass are proposed. The results of optimization indicate that the carbon debt payback period is about 70 years, and the carbon dioxide in the atmosphere increases by more than 50% at a maximum and 3% at a steady state. These are theoretically predicted best results, which are expected to be worse in reality. Therefore, biomass is not truly carbon neutral, and it is inappropriate as an energy source alternative to fossil fuels. The method proposed in this work is expected to be able to contribute to the approach to carbon neutrality by minimizing present and future carbon debt of the bioenergy that is already in use.

• Land and Housing Review
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• v.3 no.2
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• pp.187-193
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• 2012

A technology that newly attract attention in the area of energy-related study is the energy harvesting(or scavenging) technology. In this paper, the performance of power generation for the energy harvesting block with a combination of piezoelectric technology and electromagnetic technology among various energy harvesting technologies was investigated. The goal of this study is to evaluate on the applicability of our developed energy harvesting block into the field of urban & housing. First, we evaluated the performance of power generation for the multi-layer energy harvester at laboratory scale. Second, we described the features of our developed prototype module that includes amplification technologies to improve power density per module and evaluated the performance of power generation for the energy harvesting block in a variety of ways. From the test results, the developed product increased the performance of power generation up to 255% or 505% compared to the existing product and its superiority were shown. Finally, we suggested the direction for the improvement of the energy harvesting block module.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.155-155
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• 2017

최근 애플망고 스마트 농가에 에너지 사용량이 증가됨에 따라 에너지 절감을 위한 대책들과 화석연료를 대체하는 다양한 신재생에너지 도입에 대한 요구들이 늘고있다. 본 연구에서는 애플망고 스마트 농가에 여러 에너지원들을 혼합하여 사용할 수 있도록 실증시험 모델을 구축하고 운영함으로써 그 효용성을 검토하고자 하였다. 우선 애플망고 특성을 고려한 비닐온실의 최대 냉난방부하량과 에너지모델을 분석하여 신재생 에너지원들의 혼합 및 기존 공조설비와의 연계를 계산하였다. 애플망고 시험 농지로는 재배에 적합한 제주도 서귀포를 선정하였으며, 기존의 경유 난방기를 사용하는 비교시험 하우스, 기존의 경유와 태양광, 지하 공기 히트펌프 난방기를 혼합하여 사용하는 실증시험 하우스, 경유와 지하공기 히트펌프 난방기를 사용하는 대조시험 하우스를 10~11월 두 달간 운영하여 그 결과들을 평가하였다. 온실 내외부에 온도, 습도, CO2를 측정할 수 있는 6점의 센서부들을 설치하였고, 적산 전력계와 유량계를 설치하여 데이터를 수집하였으며, 모든 시험 데이터는 모바일 원격으로 제어 및 모니터링이 가능하도록 구성하였다. 시험 결과, 각 하우스들에서 수확한 과실의 수량과 품질은 유사하게 평가되었지만, 실증시험 하우스의 난방비가 비교시험 하우스보다 절감되었다. 하지만 실증시험 하우스의 경우 높은 시설유지비로 인해 이를 고려한 사용료는 비교시험 하우스보다 더 비싸게 평가되었다. 본 연구를 통해 생산된 잉여전력을 매전할 때 이로 인한 이용비는 비교시험 하우스보다 더 경제적임을 확인할 수 있었다. 또한 기존의 경유와 지하공기 히트펌프 난방기를 혼합한 대조시험 하우스의 난방비용이 경제성에서 더 유리함을 알 수 있었다. 따라서 본 연구를 통해 애플망고 스마트 농가에 적합한 에너지-믹스 모델을 구축할 수 있었으며, 다양한 신재생에너지들의 효용성들을 검토할 수 있었다.

• Proceedings of the Korean Society of Food and Cookery Science Conference
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• 2003.10a
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• pp.89-89
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• 2003

고사리(Pteridium aquilinum)는 봄철에 어린싹을 삶아 물에 담구었다가 먹거나 건조시켜 저장해서 이용하는데 현재 유통되고 있는 건고사리는 수확, 건조 및 저장 중에 비위생적인 관리 둥에 의해 미생물의 중식 및 해충의 발생 등으로 품질이 크게 저하되어 저장상 많은 어려움을 안고 있다. 살균, 살충을 위한 방사선의 식품에의 이용은 그 건전성과 경제적 타당성이 인정되어 여러나라에서 실용화 되고 있다. 방사선 조사된 건고사리는 선행연구에서 재수화성이 증대되었고, 조리에 의한 연화시간이 단축되어 에너지 절감의 효과가 있었다. (중략)

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2003.04a
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• pp.6-14
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• 2003

북한의 식량 상황이 악화된 근본적인 원인은 생산 주체에 대한 인센티브 부족, 농업환경을 보면 경작지 면적이 전체 20% 정도로 낮고, 무상기일이 135-180일로 짧으며, 토양의 비옥도 저하, 삼림파괴로 인한 토양 유실증가, 가뭄, 홍수, 태풍과 같은 자연 재해가 계속되고 있다. 농업 구조적인 요인들로는 농업에 투입되는 에너지 부족(연료, 비료, 농약, 전기 등), 농업 기계화율 정도가 높았으나 노후화에 따른 예비 부품 부족으로 인한 활용률의 저하, 양질의 종자확보 부족, 갖추고 있는 관개 시설의 노후화로 인한 관개시설 활용과 관수 효율의 저하, 농산물 수확 후 수송과 저장 과정에서 손실증가 등을 들수 있다. (중략)