• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.90-95
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• 2015

This paper describes IEC 61727 standard of Photovoltaic (PV) systems -Characteristics of the utility interface. IEC 61727 standard tests include utility compatibility and personnel safety and equipment protection of PV inverter performance functions. Especially utility compatibility part includes test items of 1) voltage, current and frequency, 2) normal voltage operating range, 3) flicker, 4) DC injection, 5) normal frequency operating range, 6) harmonics and 7) waveform distortion, 8) power factor of PV inverter. Also personnel safety and equipment protection part includes test items 1)loss of utility voltage, 2)over/under voltage and frequency, 3)Islanding protection, 4)response to utility recovery, 5)earthing, 6)short circuit protection, 7)Isolation and switching of PV inverter. In this paper, each item of IEC 61727 standard test is studied and analyzed and finally full tested by PV inverter performance function.

• 한국지진공학회논문집
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• 제28권4호
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• pp.205-213
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• 2024

In the seismic evaluation of underground utility tunnels, selecting an analytical method is critical to estimating reasonable seismic responses. In simplified pseudo-static analysis methods widely applied to typical seismic design and evaluation of underground tunnels in practice, it is essential to check whether the methods provide valid results for cut-and-cover tunnels buried in shallow to medium depth. The differences between the two simplified pseudo-static methods are discussed in this study, and the analysis results are compared to those obtained from FLAC models. In addition to the analysis methods, seismic site classification, overburden soil depth, and sectional configuration are considered variables to examine their effects on the seismic response of underground utility tunnels. Based on the analysis results, the characteristics derived from the concepts and details of each simplified model are discussed. Also, general observations are made for the application of simplified analysis methods.

• 디지털산업정보학회논문지
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• 제6권1호
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• pp.159-167
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• 2010

We research a competitive advantage of telecom bundling package of three mobile telecom company by figuring out utility that consumers perceived and focused on mobile telecom and high speed internet in one bundled package. As a method, conjoint analysis was applied. And in conclusion, consumers considered retaining mobile telecom company as the most important factor to them and branding as the following important one when one bundled package of telecom service is provided in total market. When the market is divided into two submarkets and the second largest submarket is analyzed personal bundled package was most important and three year agreement with a stipulated discount has the highest utility. As a result of this analysis, mobile telecom company managers need to organize bundled package after consideration of their current position and brand power in the market, and then devise proper market strategy

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.548-553
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• 2003

The frequency and phase angle of the utility voltage are important in many industrial systems. this paper present a detailed analysis of single-phase digital PLL control for utility connected systems. and its performance under utility conditions with noise is discussed. The experimental results demonstrate phase tracking capability in the single-phase grid-connected operation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.252-254
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• 2004

This paper studies power quality problem of utility interconnected distributed generation. Recently, electronic devices that are sensitive to power quality have been increasing. Both utility and customer are interested in power quality problem. Therefore, we studied an effect of utility power quality caused by distributed generation. We detect and analysis voltage sag which is one of power quality indicator. Also, we used Matlab to simulate power quality problem.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2020년도 제62차 하계학술대회논문집 28권2호
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• pp.83-84
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• 2020

Sum Utility를 최적화하는 Convex Optimization Algorithm을 제안한다. 일반적으로, Sum Utility 최적화 문제는 Non Convex Optimization Problem이다. 하지만, '상대간섭'과 '간섭주요화'를 활용하여 Non Convex Optimization Problem이 간섭구간에 따라 Convex Optimization으로 해결할 수 있음을 확인하였다. 특히, 유틸리티 함수는 상대간섭 0.1 이하에서는 오목함수임을 확인하였다. 실험결과 상대간섭이 작아질수록 제안하는 알고리즘에 의한 Sum Utility는 증가함을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.75-76
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• 2007

Several kinds of High Temperature Superconducting(HTS) power cables have already been developed and evaluated for use in the utility power network. HTS power cable is expected to be used as a very powerful energy delivery system supplying electric power for densely populated cities in the near future, because HTS power cable is capable of the high current density delivery with low AC loss and the size effect comparing with the conventional cable whose capacity is same. Before applying the HTS power cable to real utility network system analysis should be carried out by some simulation tools. Hereby the electrical power system analysis is very important for the practical use of HTS power devices. In this paper, authors propose a real-time simulation method which incorporates a real HTS tapes into the simulated 22.9kV utility power network system using Real Time Digital Simulator(RTDS). For the simulation analysis, a test sample of HTS tapes was actually manufactured, and the transient phenomenon of HTS power cable system was analyzed in the simulated utility power network.

• 한국산학기술학회논문지
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• 제21권8호
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• pp.563-571
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• 2020

공동구의 설치 목적은 반복굴착 방지, 재해·재난 예방 등이나 국내 공동구는 신도시 개발 계획에 포함되어 건설되었으며, 현재 기관별 의견 충돌 및 재원 조달의 문제로 공동구 설치는 어려운 실정이다. 본 논문에서는 신도시 및 기존 시가지의 공동구 활성화 개선방안 제시를 위하여 단계별 절차를 기준으로 연구를 진행하였다. 먼저 공동구 관련법 및 현황 조사를 수행하였으며, 현황에 대한 검토 및 분석을 기반으로 문제점을 도출하였다. 마지막으로 문제점 해결을 위한 개선방안을 제시하는 방법을 적용하였다. 관련법과 문제점을 기반으로 공동구 설치의무규모 선정을 위하여 최근 개발사업(도시개발, 택지개발, 도시재생) 현황을 분석하였으며, 공동구 설치의무규모 200만㎡ 이하에서의 경제적 타당성 분석을 통하여 적정 규모를 검토하였다. 신도시 및 기존시가지를 고려하여 공동구 추가설치지역 및 점용기관의 부담 경감을 위한 관리비 지원사항을 제안하였다. 또한 공동구 설치지역 검토를 위해 기본계획 등에 관한 세부 사항에 대하여 개선방안을 제시하였다. 본 논문은 향후 지역의 공동구 계획 및 설치 시 이해관계자의 원활한 업무 수행에 도움이 될 것으로 판단된다.

• 보건행정학회지
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• 제17권4호
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• pp.113-133
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• 2007

The present study was conducted to measure health-related utility for post-menopausal symptoms among Korean woman. A survey questionnaire was developed to measure utility based on visual analogue scale(VAS) and time trade-off method (TTO). From January 29 to February 3, 2007, a face-to-face interview was conducted with 274 women aged 45 to 60 to ask about their subjective utility for hypothetical health status of mild or severe post-menopausal symptoms. Among the participants, 160 were recruited from outpatient departments of 3 hospitals and 114 from 2 sports centers located in Seoul. For mild symptom, the average utility score of the respondents was $0.63{\pm}0.14$ based on VAS and $0.61{\pm}0.26$ based on ITO. For severe symptoms, the average utility was $0.39{\pm}0.16$(VAS) and $0.44{\pm}0.27$ (TTO). For severe symptom, a higher utility score was observed for TTO than for VAS, which is consistent with earlier studies and thus supports the validity of the utility measurement in this study. Overall, the severity of post-menopausal symptoms of the respondents themselves was not significantly associated with the utility score that the respondents answered for hypothetical health status. Multiple regression analysis results showed that the utility score was significantly higher among respondents with older age, higher education, higher family income, and from hospitals. It is expected that the utility score measured in this study will enhance the understanding of the quality of life of women after menopause and will be used to conduct cost-utility analysis of health care interventions to treat post-menopausal symptoms.

• 한국콘텐츠학회논문지
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• 제5권5호
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• pp.266-272
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• 2005

본 연구는 회계정보시스템이 업무성과에 미치는 영향을 실증적으로 분석하기 위하여 크론바흐 알파, 요인분석, 분산분석, 회귀분석을 실시하였다. 본 연구의 분석결과는 다음과 같다. 첫째, ASS 유용성과 업무성과간의 회귀분석에 대한 통계적 유의성은 매우 유의한 것으로 나타났다. 둘째, 분산분석에서 시스템 운용성과와 시스템 만족도는 유의한 수준에 도달하지 못하고 있었다. 셋째, 정보정확도와 정보시스템 만족도에 대한 투입변수는 IT능력변수에 대해 상승효과가 있는 것으로 분석되었다.