• Smart Structures and Systems
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• 제17권3호
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• pp.413-429
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• 2016

The recent research on proper orthogonal decomposition (POD) has revealed the linkage between proper orthogonal modes and linear normal modes. This paper presents an investigation into the modal identifiability of an instrumented cable-stayed bridge using an adapted POD technique with a band-pass filtering scheme. The band-pass POD method is applied to the datasets available for this benchmark study, aiming to identify the vibration modes of the bridge and find out the so-called deficient modes which are unidentifiable under normal excitation conditions. It turns out that the second mode of the bridge cannot be stably identified under weak wind conditions and is therefore regarded as a deficient mode. To judge if the deficient mode is due to its low contribution to the structural response under weak wind conditions, modal coordinates are derived for different modes by the band-pass POD technique and an energy participation factor is defined to evaluate the energy participation of each vibration mode under different wind excitation conditions. From the non-blind datasets, it is found that the vibration modes can be reliably identified only when the energy participation factor exceeds a certain threshold value. With the identified threshold value, modal identifiability in use of the blind datasets from the same structure is examined.

• 한국전산구조공학회논문집
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• 제22권4호
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• pp.349-354
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• 2009

초고층 건물의 안전성 및 사용성을 합리적으로 확보하고 유지하기 위해서 부재의 구조 반응 모니터링은 필요하다. 이러한 대형 건물의 건전도 모니터링은 최근 들어 많은 연구자들에 의해서 관심 되어지고 있지만 건물 특성상 계측 대상 부재가 많고 하중과 구조반응의 관계가 복잡하기 때문에 센싱 부재 선정의 어려움으로 그 적용에 한계가 있다. 본 논문에서는 부재의 변위기여도 및 변형에너지밀도를 기반으로 초고층 건물의 안전성 모니터링을 위한 구조반응 계측 부재 선정에 대한 연구를 수행하였다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.478-485
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• 2017

Urban DC railways have played an important role in urban transportation, and railway operation and energy management have been emphasized to be important to achieve maximum efficiency from existing infrastructure. Fast, accurate DC railway power flow analysis is required to operate a DC railway efficiently, and this paper proposes a novel methodology to analyze the DC railway power network by implementing the participation factor (PF). The PF concept consists of a correlation between the vehicle and the substation, as explained using zones based on the position of the vehicles running on the route. Then, the DC railway powerflow is calculated using the PF concept. Finally, the usability of the proposed method was validated via case studies with actual railway operation data, and we discuss some of the advantages of the suggested methodology.

• 조명전기설비학회논문지
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• 제27권1호
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• pp.17-23
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• 2013

The BESS(Battery Energy Storage System) is an useful device for load leveling, but the high cost, installation space and safety issues are the main barriers for supplying it widely. The important factor in supplying BESS to customers successfully is the payback period. As most of the H/W cost factors are uncontrollable, the optimization of storage volume can be useful factor in improving payback period. In order to obtain optimized BESS volume, the load factor, demand ratio, peak shaving ratio, electric rates and benefits from DR participation of customer should be analyzed. In this paper, we could verify the peak cutting capability and cost effectiveness under the some proposed conditions and changing value of PCS and battery based on the customers data after volume optimization process was applied, and we can identified the saturation point of load factor and shortening of customer's payback period.

• 한국환경과학회지
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• 제23권8호
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• pp.1507-1512
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• 2014

Recognition of Korean pre-service elementary school teachers concerning the factor for the environmental class was investigated and analyzed by the factorial analysis. Korean pre-service elementary school teachers are aware of the factor of 'participation in environment' as well as the factor of 'environmental knowledge' for the environmental class. Furthermore, they had a very positive attitude about the factor of 'participation in environment'.

• 에너지공학
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• 제27권4호
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• pp.36-49
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• 2018

본 연구에서는 일반인을 대상으로 일반 설문과 선택형 컨조인트 분석(Choice Based Conjoint Analysis: CBC Analysis)을 통해 태양광 발전을 중심으로 신재생에너지와 신재생에너지 사업 전반에 대한 인식을 파악하고, 계층적 베이지안 모형(Hierarchical Bayesian Model)을 이용하여 신재생에너지 사업에 대한 일반 국민의 선호를 정량적으로 분석하였다. 그 결과, 응답자들은 신재생에너지 사업에 참여하게 될 경우 누가 사업을 주도 하는가, 즉 사업을 주도하는 주체에 대해 가장 중요하게 생각하며, 그 뒤를 이어 발전소의 위치와 국민들의 참여 방식과 이익배분에 대해서 중요하게 생각하였고, 상대적으로 사업에 대한 국민들의 의사결정 참여는 중요하지 않은 것으로 나타났다. 또한 응답자들은 신재생에너지 사업에 참여할 경우, 정보 공유나 의사 개진, 협조, 조율과 같은 사업에 대한 지원 활동(volunteering) 보다는 대출이나 지분 소유를 통한 투자 참여를 선호하였고, 따라서 의사 결정 참여와 같은 사업의 절차적(procedural justice) 측면 보다는 이익의 배분과 같은 분배적(distributional justice) 측면에 관심이 더 높았다. 각 사업의 속성 수준별 부분 효용의 크기에 따른 분석에서는, 지방자치단체 주도 하에 국민들이 신재생에너지 사업에 대해 주식을 소유하고 사업의 수익률에 연동하여 배당을 받는 방식으로 참여하고 산지나 해변보다는 지붕에 발전 시설을 설치하는 것을 선호하였고, 반대로 전문 개발회사와 투자회사 주도로 정보공유, 협의, 조율과 모니터링에 참여하고 이익의 일부를 마을 복지나 발전 기금으로 받으며, 발전소를 산지나 임야에 짓는 경우를 선호하지 않았다. 본 연구는 직접적인 설문과 면담 등의 질적 연구만으로는 밝혀내기 어려웠던 국민 참여를 전제한 신재생에너지 사업 속성의 영향력을 계량화된 모형을 통해 입증하였다는 점에서 의의를 가지며, 따라서 본 연구에서 나타난 신재생에너지 사업에 대한 일반인의 인식과 선호 분석의 결과는 향후 국민 참여형 신재생에너지 사업의 방향 수립 시 주민 수용성을 높이는 기초 자료로 활용될 수 있을 것이다.

• 신재생에너지
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• 제5권3호
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• pp.49-55
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• 2009

Human resource for the new and renewable energy technology is an important factor in the respect of the sustainable growth and energy security. In this paper, we focused on measuring the economic effect of human resource development on new and renewable energy development programs. The human capital accumulation model developed by Mincer (1974) was modified in terms of the rate of the researchers' investment in human capital. As a result of a empirical case study, the value of human capital was estimated by 102 million Korean won per year worth 18% of the project labor cost. In case of the assumption of 100% participation of researchers, the level of human capital accumulation increased to 914 million Korean won per year. These results imply that the new and renewable energy development programs has been successful, on the concept of learning by doing, in terms of providing the researchers with opportunities to accumulate human capital.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1074-1080
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• 2009

A method for determining the geometric stability characteristics of a brake corner module (BCM) is presented. Since disc brake "squeal" noise typically occurs at unstable resonant frequencies of a system, the likelihood of disc brake squeal for a particular design can be determined. Finite element methods are used to derive complex eigenvalue for a brake corner module. Some unstable modes calculated by finite element methods correspond to squeal noise data. Through kinetic energy participation analysis for each part of BCM, we can efficiently predict squeal noise data.

• 신재생에너지
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• 제17권2호
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• pp.9-23
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• 2021

In Korea, various community investment renewable project models are being implemented to increase community acceptance of renewable energy. An important factor for enhancing local acceptance is that renewable energy projects have a positive effect on revitalizing the local economy such as income increase or job creation for residents and local companies. To maximize the local economic effect of large-scale community investment renewable energy projects, this study developed an evaluation index for local economy activation, whose indicators are the local return on investment, local companies' participation, local job creation, regional cooperation, transparency, and governance. Analysis of existing evaluation indicators and current renewable projects, financial analysis, and expert interviews were used in this research. The pilot evaluation determined that, the local economic effect was high in the following order: a fund investment wind project (Gangwon), benefit-sharing wind project (Jeju), and general wind project. In particular, residents' investment amount, the number of participating residents, and the amount and transparency of the regional cooperation fund were key factors to expand the effect of local economy activation. This evaluation index could be used in public bidding for renewable energy projects such as offshore wind zoning areas of local government.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.686-688
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• 2004

We suggest that the core factor which can be established successfully pushing ahead with domestic load management program is finding and keeping management of controllable load resources. We know that load management is mostly the maximum demand power management and participation of DLC program. This paper suggests the way coping with load management suggesting model which air conditioning and heating load facilities are applied to DU program.