• Advances in environmental research
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• 제2권1호
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• pp.51-60
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• 2013

The paper aims to characterise the waste generated in municipality of Varanasi, the most populated city in the state of Uttar Pradesh, India. MSW is a heterogeneous waste and composition of the waste varied from season to season. The generation, collection and management of waste have become a major environmental problem in most of the developing cities. MSW was collected from open dumping grounds for 2 consecutive years. Each year was classified into 3 seasons of 4 months. On analysis it was found that the biodegradable fraction is always more than other fractions with a minimum of 48.25% in rainy season. With such a high fraction of biodegradable wastes, options such as composting and biomethanation could be tried to convert waste into energy. The average weight of waste generation at present is 0.460 kg per capita per day. The study showed that waste generation and collection were increasing every year, which may be attributed to increase in population.

• 대한전기학회논문지:전력기술부문A
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• 제53권6호
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• pp.340-349
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• 2004

Recently, the needs and concerns for the power loss are increasing according to the energy conservation at the level of the national policies and power utilities's business strategies. Especially, the issue of the power loss is the main factor for the determining the electric pricing rates in the circumstances of the deregulation of electrical industry. However, because of the lacking of management for power loss load factors (LLF), it is difficult to make a calculation for the power loss and to make a decision for the electric rates. And loss factor(k-factor), which is a most important factor for calculation of the distribution power loss, has been used as a fixed value of 0.32 since the fiscal year 1973. Therefore, This study presents the statistical calculation methods of the loss factors classified by load types and seasons by using the practical data of 65 primary feeders which are selected by proper procedures. Based on the above the algorithms and methods, the optimal method of the distribution loss management classified by facilities such as primary feeders, distribution transformers and secondary feeders is presented. The simulation results show the effectiveness and usefulness of the proposed methods.

• 디지털융복합연구
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• 제10권11호
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• pp.449-457
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• 2012

본 연구의 목적은 PET/CT 검사시 공간선량을 측정 비교함으로써 방사선 발생원과 종사자간 선량의 상관관계를 규명하고 효율적인 관리를 통해 피폭선량을 감소시키는데 있다. 최근 PET/CT 검사의 증가는 동위원소 사용량의 증가와 더불어 종사자의 피폭 증가의 원인이 되고 있다. 따라서 각 방사선 발생원에서의 공간선량을 비교 분석하고 개인방호복과 차폐체 사용에 관한 연구를 수행하였다. 양전자 방출핵종인 $^{18}F$ 방출 감마선 고에너지(511 keV)에서 개인방호복(0.5 mm pb) 사용은 미사용 시 보다 더 많은 피폭을 초래함을 확인하였다.

• KIEE International Transactions on Power Engineering
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• 제5A권2호
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• pp.109-115
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• 2005

Recently, the needs and concerns regarding power loss have been increasing according to energy conservation at the level of the national policies and the business strategies of power utilities. In particular, the issue of power loss is the main factor for determining rates for electrical consumption in the deregulation of the electrical industry. However, because of the lack of management for power loss load factors (LLF) it is difficult to make a calculation for power loss and to make a decision concerning the electric rates. Furthermore, loss factor (k-factor) in Korea, which is of primary significance in the calculation of distribution power loss, has been used as a fixed value of 0.32 since the fiscal year 1973. Therefore, this study presents the statistical calculation methods of the loss factors classified by load types and seasons by using the practical data of 65 primary feeders that have been selected by appropriate procedures. Based on the above, the algorithms and methods, as well as the optimal method of the distribution loss management classified by facilities such as primary feeders, distribution transformers and secondary feeders is presented. The simulation results demonstrate the effectiveness and usefulness of the proposed methods.

• 마이크로전자및패키징학회지
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• 제26권3호
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• pp.15-22
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• 2019

In these days, importance of the power electronic devices and modules keeps increasing due to electric vehicles and energy saving requirements. However, current silicon-based power devices showed several limitations. Therefore, wide band gap (WBG) semiconductors such as SiC, GaN, and $Ga_2O_3$ have been developed to replace the silicon power devices. WBG devices show superior performances in terms of device operation in harsh environments such as higher temperatures, voltages and switching speed than silicon-based technology. In power devices, the reliability of the devices and module package is the critically important to guarantee the normal operation and lifetime of the devices. In this paper, we reviewed the recent trends of the power devices based on WBG semiconductors as well as expected future technology. We also presented an overview of the recent package module and fabrication technologies such as direct bonded copper and active metal brazing technology. In addition, the recent heat management technologies of the power modules, which should be improved due to the increased power density in high temperature environments, are described.

• Architectural research
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• 제21권3호
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• pp.69-77
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• 2019

Architects are facing increasing risks that result from heightened expectations of benefits and performance when designing green buildings compared to traditional buildings. This study aims to explore the possible risk factors for architects in green building projects in South Korea and assess risk mitigation measures. To attain this goal, 14 risk factors and 12 mitigation measures were determined through an extensive literature review. A questionnaire was administered to architects practicing green building design and criticality index was employed to assess major risk factors and mitigation measures. This study identified 'adoption of new technology and process', 'green building certification results', 'building products and materials', and 'energy saving uncertainty' as the major risk factors of green building projects. Additionally, the questionnaire proposed 'contract indicating each party's role, liability, and limitations clearly', 'utilizing integrated design process', and 'understanding client's goal in green building projects' as the three most effective risk mitigation measures in designing green buildings. There are few studies that focus on architects' perceived risks concerning green building projects; this study contributes to a deeper knowledge and attempts to fill the current literature gap, which would benefit South Korea's green building design practice by aiding in the development of better risk management strategies.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.730-731
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• 2015

This study aims at giving the framework to estimate the environmental load at planning and schematic phase. With increasing awareness of environmental issues, the effort to reduce the environmental impacts caused by human activity has been increasingly enlarged. So far most of researches estimating CO₂ emissions have analyzed energy consumption based on BOQ (Bills of Quantity) acquired after detailed design. There is also lack of reliability in the estimated environmental impact using the basic unit of a facility at the planning stage, because it uses a limited specific section of historical data. Thus, this study is targeted at developing framework to assess reliable environmental loads based on information available at project early phases by making case-bases from historical design information on PSC Beam Bridge. Historical database is built on the basis of the LCA (Life Cycle Assessment) and in order to set input information for estimating model, the literature about information in an early project phase are reviewed. Using the information available in the planning and schematic design stage, the Framework is presented to estimate the environmental load in an early stage in the project. Developing an environmental load estimation model in accordance with the Framework presented in this study, it is expected that the environmental load in the initial project phase can be estimated more quickly and accurately.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.465-473
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• 2015

The increasing need to improve transient security assessment of existing or forecasted operating conditions of networks by power system operators is major concern of the power system security monitoring problem at the Energy Management Systems. This paper proposes a preventive control of transient stability with generation rescheduling based on rotor trajectory index obtained using time domain simulations. This index may help power engineers in making operational decision and to obtain a generation configuration with better transient security dispatch. The effectiveness of the proposed methodology is demonstrated on IEEE 39-bus New England system for a three phase fault at different loading conditions with single and multiple line outage cases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.816-818
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• 2005

In this paper, we have developed an hourly operating strategy for Direct load control (DLC) considering the efficiency of DLC program and increasing the utility of DLC resource. According to the operating code for DLC, the DLC center should curtail the load for 4 hours when the control notification has been enforced. Since the above strategy may limit the participation of entities, who intend to take part in the DLC program, the new strategy to mitigate the above limitation is required. In this paper, we have developed the operating strategy of DLC program and the mechanism to apply the proposed strategy in the DLC center. The proposed strategy makes the important role from the view of guaranteing the effective alternative raising the participation and avoiding the penalty of the entities.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.429-430
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• 2018

모바일 장치의 등장은 이미지 검색 방법을 모바일 장치의 메모리, 속도, 에너지 및 대역폭과 같은 제약에 적용해야 할 필요성이 커지고 있다. 모바일 폰에서 이미지 검색의 제약 사항을 해결하기 위한 필요성이 높아지고 있다. 따라서 본 논문은 이미지에 태그를 추가하여 모바일 환경에서의 이미지 관리를 위한 효율적인 검색과 이미지의 유사도를 이용한 중복 파일의 제거 방법을 제안한다. 제안된 방법은 효율적인 면에서 추가 비용이 없으며 모바일 장치에 필요한 데이터의 양을 줄일 수 있다.