• Earthquakes and Structures
• /
• 제17권2호
• /
• pp.233-244
• /
• 2019

In this work, we have studied the effects of different soil thicknesses, haunch heights, reinforcement forms and construction technologies on the seismic performance of a composite precast fabricated utility tunnel by pseudo-static tests. Five concrete specimens were designed and fabricated for low-cycle reciprocating load tests. The hysteretic behavior of composite precast fabricated utility tunnel under simulated seismic waves and the strain law of steel bars were analyzed. Test results showed that composite precast fabricated utility tunnel met the requirements of current codes and had good anti-seismic performance. The use of a closed integral arrangement of steel bars inside utility tunnel structure as well as diagonal reinforcement bars at its haunches improved the integrity of the whole structure and increased the bearing capacity of the structure by about 1.5%. Increasing the thickness of covering soil within a certain range was beneficial to the earthquake resistance of the structure, and the energy consumption was increased by 10%. Increasing haunch height within a certain range increased the bearing capacity of the structure by up to about 19% and energy consumption by up to 30%. The specimen with the lowest haunch height showed strong structural deformation with ductility coefficient of 4.93. It was found that the interfaces of haunches, post-casting self-compacting concrete, and prefabricated parts were the weak points of utility tunnel structures. Combining the failure phenomena of test structures with their related codes, we proposed improvement measures for construction technology, which could provide a reference for the construction and design of practical projects.

• Journal of Radiation Protection and Research
• /
• 제29권1호
• /
• pp.65-71
• /
• 2004

원자력 시설의 사고시 환경으로 방출된 방사성물질로부터 초기 주민의 피해 최소화를 위한 대응행위 결정지원 방안으로 다속성 효용분석 법이 고찰되었다. 속성의 효용함수는 비선형 2차 함수로 가정하였으며, 속성의 가중계수는 swing weighting 방법을 사용하여 결정하였다. 본 연구는 원자력시설의 사고시 초기 대응행위 결정지원을 위한 다속성 효용분석법의 적용성에 한정하며, 스트레스 등과 같은 비정량적 속성은 아직까지 자료의 부족으로 포함하지 않았다. 가상사고 시나리오를 구성하여 무대응, 대피, 소개에 대해 속성 값의 변화에 따른 행위에 대한 총 효응 값을 고찰하였다. 적용한 결과, 피폭선량과 선량의 금전가의 변화에 따라 행위의 총 효용 값은 뚜렷이 다르게 나타났다. 피폭선량과 선량의 금전가의 증가에 따라 대피보다 사회적 영향 등 여러 측면에서 보다 극단적인 대응행위인 소개의 총 효용 값의 순위는 뚜렷이 증가한 반면, 무 대응의 순위는 감소하였다. 선량의 기대 확률도 대응행위 결정지원에 있어서 중요한 변수로 나타났는데, 상대적으로 고선량의 기대 확률이 높을수록 행위의 우선 순위가 바뀌는 교차점에서 선량의 금전가는 보다 낮게 나타냈다. 또한 선량에 대한 회피심리가 강하게 적응할수록 행위의 우선 순위가 바뀌는 선량의 교차점은 보다 낮게 나타났다.

• 한국안전학회지
• /
• 제31권3호
• /
• pp.143-155
• /
• 2016

Recently, a massive loss of life and property is occurring in Korea due to traffic accidents, with the rapid increase in cars. For improvement of traffic safety, the Korea Transportation Safety Authority intensively analyzes accident data in local governments with low traffic safety index, performs a field investigation to extract problems and offers local governments improvements for problems, by conducting the 'Special Survey of Actual Conditions of Traffic Safety' each year, starting 2008. But local governments cannot strongly push forward the improvement projects due to the limited budget and the uncertainty of the improvement plan effects. Therefore, this study suggested a model which applied the Utility concept to the AHP theory, in order to efficiently decide a priority of the improvement plans in accident black spots in consideration of the limited budget of local governments. The number of accidents in each spot for improvement and accident severity, traffic volume, pedestrian volume, the improvement project cost and the accident reduction effect were chosen as evaluation factors for deciding a priority, and data about the improvement plan costs and the accident reduction effects, traffic accidents and traffic volume in the spots to undergo the special research on the real condition of traffic accident in the past were collected from the existing studies. Then, regression analysis was carried out and the Utility Curve of each evaluation factor was computed. Based on the AHP analysis findings, this study devised a priority decision method which calculated the weight and the utility function of each evaluation factor and compared the total utility values. The AHP analysis findings showed that among the evaluation factors, accident severity had the biggest importance and it was followed by the improvement plan cost, the number of accidents, the improvement effect, traffic volume and pedestrian volume. The calculated utility function shows a rise in utility, as the variables of the 5 evaluation factors; the number of accidents, accident severity, the improvement plan effect, traffic volume and pedestrian volume increase and a fall in utility, as the variables of the improvement plan cost increase, since the improvement plan cost is included in the budget spent by a local government.

• 한국전자거래학회지
• /
• 제26권2호
• /
• pp.1-17
• /
• 2021

본 연구는 디지털헬스케어서비스에서 사용자기대와 사용자효용의 매개요인을 사용하여 서비스 품질의 특성들이 지속사용의도에 미치는 효과를 분석하였다. 첫째, 독립요인을 서비스품질 차원으로 통합하였으며, 기존 연구들을 토대로 독립요인들을 도출하였다. 도출된 독립요인은 기술적특성, 사용자특성, 의료서비스특성 등의 3개의 관점으로 구분하였으며, 각각의 독립요인 특성이 지속사용의도에 어떻게 영향을 주는지를 연구하였다. 둘째는 사용자기대와 사용자효용이라는 2개의 매개요인들이 독립요인과 종속요인을 매개하는지를 분석하였다. 본 연구에서는 357개의 설문을 사용하였으며 의미 있는 분석결과는 사용자특성 요인이 사용자기대와 사용자 효용 그리고 지속사용의도에 연속적으로 영향을 미치는 독립요인이라는 것을 발견하였다. 분석 결과을 요약하면 다음과 같다. (1) 사용자특성 요인은 사용자기대와 사용자효용 매개요인에 영향을 주고, 이들 매개요인들은 지속사용의도 종속요인에 영향을 미친다. (2) 기능성, 호환성 그리고 편의성 하위요인들로 구성된 기술적특성 독립요인과 혁신성 하위요인을 갖는 사용자 특성 독립요인은 사용자기대 매개요인에 영향을 주고, 사용자기대 매개요인은 지속사용의도 종속 요인에 영향을 준다. (3) 신뢰성, 운영용이성, 안전성 그리고 정확도 하위요인들로 구성된 의료 서비스특성 독립요인은 사용자효용 매개요인에 영향을 주고, 사용자효용 매개요인은 다시 지속 사용의도 종속요인에 영향을 미친다.

• 전력전자학회논문지
• /
• 제4권4호
• /
• pp.325-331
• /
• 1999

계통연계형 태양광발전시스템에서는 계통과 태양광시스템을 연계하기 위해 PWM 인버터가 이용된다. 인버터 시스템을 연속전류모드로 운전하면 맥동이 발생하게 되고, 직류전류의 맥동발생은 교류전류파형의 왜형을 가져온다. 본 연구에서는 직류입력전류의 맥동을 감소시키기 위하여 불연속모드 승강압초퍼로 인버터를 운전한다. 직류 전류에 포함된 고조파성분을 리플성분과 직류성분으로 분리하여 해석하고, 맥동이 없는 일정한 직류전류를 태양 전지로부터 인버터로 공급한다. 제안하는 인버터시스템은 단위 역률로 부하와 계통에 교류전류를 공급한다.

• 전기학회논문지P
• /
• 제54권3호
• /
• pp.111-118
• /
• 2005

Since the residential load is an AC load and the output of solar cell is DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feed-forward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• 수산경영론집
• /
• 제47권4호
• /
• pp.45-55
• /
• 2016

The purpose of this study is to estimate the utility value of boat fishing experience marine tourism activity in Jeju Island's Chagwido. The utility value is estimated by single bounded and double-bounded dichotomous choice contingent valuation method. The contingent valuation method is used to estimate economic values for all kinds of coastal ecosystem services. The method involves directly asking people, in a survey, how much they would be willing to pay for specific environmental services. So, the method has great flexibility, allowing valuation of a wider variety of non-market goods and services than is possible with any other non-market valuation technique. This study collects the effective 504 questionnaires from boat fishing experience tourists in Jeju Island's Chagwido. The results show that the average willingness to pay amount(WTP) is estimated to be about 17,000 Korea won by single bounded and double-bounded dichotomous choice contingent valuation method. This indicates that the utility value of boat fishing experience marine tourism activity is estimated to be about 17,000 Korea won in Jeju Island's Chagwido.

• 한국주거학회논문집
• /
• 제8권2호
• /
• pp.37-47
• /
• 1997

The purpose of this study was to analyze the housing life-style shown in the modern housing life by dweling types and residents attributes to suggest the basic information useful for the housing P3an in the future, The results of this study was summarized as folldws. Firstly. interrelation between residents attributes and housing life-style showed that the unedicated, the low income and the eldery were interested in utility. On the other hand, the educated. the upper income and the young generation were interested in decoration. Secondly those who had their own houses and never moved were interested inutility in terms of residents attributes Utility was showed high in all housing style in terms of before moving in house. Thirdly, those who wanted move and stay both interested in decoration and utility in terms of will of resident. It was also shown that those who wanted to move big cities were interested in increasing property. Fourthly, the housing life-style by dwelling types showed that it was Possible to abtain six elements such as 'decoration', 'display'. 'liking'. 'utility', 'increase of property', and 'hiearchic order' Based on the average by each type, it was shown that while a tendency toward utility was generally high, especially, the many-storied apartment was high for display.

• 한국안전학회지
• /
• 제28권5호
• /
• pp.35-40
• /
• 2013

Recently reclamation land is largely developed to utilize the land according to economic growth. The soil of landfill is soft, low shear strength, which makes it difficult to use the equipment. A large movement is occurred on the utility tunnel under construction. The inclined land with high water level and underground facilities are widely distributed and the excess pore water pressure may occur under construction similarly to this study. Some different conditions are made to design result, such as 4m of soil piling near the construction area, heavy rainfall during 2nd excavation that may cause flow liquefaction. To analyze the cause of transverse lateral movement, Three dimensional analysis are performed to four load cases, which is original design condition, flow liquefaction by heavy rainfall, unsymmetric lateral soil pressure, and both of them simultaneously. Ten steps of full construction stage, 1st excavation for utility tunnel, construction of utility tunnel, 1st refill, piling soil from 1m to 4 m, 2nd excavation for drainage culvert, liquefaction around the utility tunnel, construction of drainage culvert and 2nd refill, are take into account to investigate the cause of movement.

• 한국정보시스템학회지:정보시스템연구
• /
• 제27권3호
• /
• pp.141-160
• /
• 2018

Purpose The purpose of this study is to verify mobile game users' perceived utilities about real (price) and virtual (Ruby) currencies, which are the major factors of in-app purchase (IAP) widely used as a business model in a mobile game industry. Design/methodology/approach By using sales volume and sales frequency data for products sold in an 'S' mobile game from the 'D' mobile game company, we conducted a conjoint analysis according to the procedure recommended by Bicheno (2009). Findings The results of this study indicate that (1) mobile game users have greater utility for a virtual currency (Ruby) than for a real currency (price), (2) mobile game users' utility for virtual (Ruby) and real (price) currencies varies depending on sales volume and sales frequency, as well as (3) mobile markets (e.g., Google Play Store vs. Apple App Store), and (4) mobile game users have greater utility for a virtual currency (Ruby) which can be used readily than later.