• Journal of the Korean Solar Energy Society
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• v.24 no.3
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• pp.85-92
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• 2004

Environmental issues become one of today's central concerns due to draining natural resources and environmental pollution. Architecture is given a great deal of weight on the evoking environmental pollution. In this point of view, polluting factors in architectural planning and construction were predicted in advance and alternative plans were studied, In investigation of alternative plans, both environmental pollution and economical efficiency of various alternatives were considered. A office building was analyzed for energy consumption and construction environmental load by appling LCA. Applying LCA to a office building includes a total amount of materials and energy consumption, environmental impacts and economical efficiency evaluation. In present study, LCA applied to electrical part of a office building and economical efficiency evaluation was considered.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.16-22
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• 2009

This paper deals with the issue of robust position tracking control and energy-saving control for a valve-controlled cylinder system using speed-controlled fixed displacement pump. The whole feedback control system is composed of a pair of interconnected subsystems, that is, valve-controlled cylinder system and load-sensing control system. From experiments it is shown that position tracking control in the load sensing control system can accomplish significant reduction in input energy to pump comparing to a conventional valve-controlled cylinder system, while exhibiting the same position tracking control accuracy.

• Annual Conference of KIPS
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• 2009.04a
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• pp.1363-1365
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• 2009

현대 사회에서 유비쿼터스 센서 네트워크 환경을 제공하기 위해 활발한 활동이 이루어지고 있다. LR-WPAN 기술인 IEEE802.15.4가 표준화 되면서 유비쿼터스 센서 네트워크의 중심 기술로 자리 매김하게 되었다. IEEE802.15 표준은 WPAN(Wireless Personal Area Network) 즉, 비교적 짧은 거리에서 휴대하여 이동할 수 있는 장치들이 근처의 다른 장치들과 통신이 가능하도록 만든 무선 네트워크 통신 표준이다. 이러한 IEEE802.15 표준들은 PHY와 MAC에 대해서만 표준을 정의 하고 있다. 센서 네트워크에서 가장 중요한 이슈중의 하나는 제한된 자원 즉, 센서 노드에 주어진 에너지를 활용하여 네트워크의 수명을 최대로 연장 하는 것이다. 본 논문에서는 NS-2 시뮬레이션을 통해 WPAN에서 노드의 전송거리에 따른 에너지 효율을 분석한다.

• Smart Media Journal
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• v.9 no.3
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• pp.52-58
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• 2020

The growing global energy demand has been the motivation for innovations for improved approaches on energy trade. The involvement of new energy market players known as prosumers have also enabled Peer-to-Peer (P2P) energy trade in microgrid communities. In this paper, a novel approach to energy trading based on Hive Strategy is proposed. The strategy aims to encourage prosumers to become workers that will meet the energy demands of consumers referred to as hives. The workers are selected based on their Prosumer Ratings (PR) and are ranked from the ones with the highest PR to the lowest. Using the PR, prosumers with the best energy consumption and generation behaviors are prioritized for energy trade. To test the proposed strategy, a simulation has conducted and the results show how the energy demand of the hive is met by the workers. Furthermore, an improvement in the pay-offs and PR of the workers are observed.

• Journal of Science Education
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• v.43 no.3
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• pp.284-299
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• 2019

The purpose of this study is to investigate elementary school students' conceptions about the energy represented in the integrated theme 'Energy and life' of the 2015 revised science curriculum. The instruments were developed to grasp students' understanding about 'the concepts of energy,' 'forms of energy,' 'conversion of energy,' and 'energy use of plants and animals.' The surveys were conducted on 92 elementary school students in Seoul. The students' answers were analyzed by descriptive statistics, clouds and semantic network analysis. The results are as follows: 'Electricity' and 'electric energy' were most frequently mentioned as the associated concepts to energy and forms of energy, respectively. Also, the daily use of energy was mixed to the use in science. According to conceptual hierarchy, understanding of energy conversion was dependent on the understanding of energy forms. Although students have basic concepts about the energy use of plants and animals, they had some misconceptions and lack of understanding. The educational implications were discussed to teach 'Energy and Life' as integrated theme in new elementary school curriculum.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.469-479
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• 1991

According to the recent paper by B. Fricke (J. Chem. Phys. 84, 862 (1986)), it is reported that the atomic polarizability (${\alpha}$) correlates very strongly with the first ionization potential (IP) within the groups of elements. In our study, we obtained very significant correlations between $ln\alpha$ and IP as well as lnIP by employing the least squares method. In examining the correlations of various atomic electronegativities with their first ionization potentials and the atomic polarizability within the groups of elements, good correlation coefficients are obtained except for groups 3a and 4a. Within the periods of elements, good correlation coefficients are obtained with no exception. This allows a very good prediction of various atomic polarizabilities undetermined.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.96-102
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• 2019

This study investigated the heat dissipation characteristics of a heat-sensitive LED. More than 80% of the power supply is converted into heat energy, which has a fatal impact on the lifetime of the LED. Therefore, the effective heat dissipation characteristics of a heatsink, such as a 30W floodlight, through forced convection were grasped and the heat transfer characteristics were tested. As a result, it was confirmed that the smaller the number of fins, the more the temperature distribution varies according to the wind velocity. In addition, the larger the number of fins, the smaller the temperature difference according to the wind velocity. Therefore, it was found through this experiment that excellent heat dissipation performance was exhibited as the heat dissipation area and wind velocity increased.

• Annual Conference of KIPS
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• 2021.05a
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• pp.51-54
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• 2021

본 논문은 차량과 보행자 간 충돌 사고를 예측하는 V2P(Vehicle to Pedestrian) 서비스에서 보행자 휴대기기의 데이터 전송 시점을 동적으로 계산함으로써 불필요한 통신을 감소시켜 에너지 효율을 향상시키는 것을 목적으로 하며, MEC(Mobile Edge Computing) 기반 V2P 서비스를 제안하였다. V2P 서비스에서는 보행자와 차량 간 충돌 가능성을 예측하기 위하여 두 객체의 실시간 GPS 데이터가 요구된다. 이때 보편적으로 보행자에 비해 차량의 이동속도가 더 빠르기 때문에 보행자가 빠르게 이동해 들어오는 주변 차량에 발견될 수 있기 위해서는 자신의 위치에는 의미 있는 변화가 발생하지 않았더라도 차량 이동속도에 맞춘 빠른 주기로 차량 혹은 중앙 클라우드 서버로 자신의 데이터를 송신해야만 한다. 이 과정에서 보행자 휴대폰의 에너지가 급속하게 소모된다. 따라서 본 연구는 이러한 문제를 해결하기 위하여 MEC 서버를 배치한 V2P 서비스를 제안하였고, 보행자가 본인의 상태 정보를 활용하여 효율적인 다음 데이터 전송 시점을 계산할 수 있는 동적시점계산 알고리즘을 제안하였다.

• Journal of Hydrogen and New Energy
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• v.35 no.2
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• pp.175-184
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• 2024

This study focuses on investigating the importance of managing greenhouse gas emissions from global energy consumption, specifically examining domestic targets for clean hydrogen production. Using life cycle assessment, we evaluated reductions in global warming potential and assessed the carbon neutrality contribution of the domestic hydrogen sector. Transitioning from brown or grey hydrogen to blue or green hydrogen can significantly reduce emissions, potentially lowering CO₂ equivalent levels by 2030 and 2050. These research findings underscore the effectiveness of clean hydrogen as an energy management strategy and offer valuable insights for technology development.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.83-92
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• 2011

This study is about an analysis of surplus solar energy by important greenhouse type using Typical Meteorological Year (TMY) data which was secured in order to provide basic data for designing an optimum thermal storage system to accumulate surplus solar energy generated in greenhouses during the daytime. The 07-auto-1 and 08-auto-1 types showed similar heat budget tendencies regardless of greenhouse types. In other words, the ratios of surplus solar energy were about 20.0~29.0% regardless of greenhouse type. About 54.0~225.0% and 53.0~218.0% of required heating energy will be able to be supplemented respectively according to the greenhouse types. The 07-mono-1 and 07-mono-3 types also showed similar heat budget tendencies regardless of greenhouse types. In other words, the ratios of surplus solar energy were about 20.0~26.0% and 21.0~27.0% respectively by greenhouse type. About 57.0~211.0% and 62.0~228.0% of required heating energy will be able to be supplemented by greenhouse type. Except for Daegwallyeong and Suwon area, other regions can cover heating energy only by surplus solar energy, according to the study.