• Structural Monitoring and Maintenance
• /
• 제2권1호
• /
• pp.49-64
• /
• 2015

This paper presents a method for assessing the risk of wave run-up and overtopping of existing coastal defences and for analysing the probability of failure of the structures under future hydraulic conditions. The recent UK climate projections are employed in the investigations of the influence of changing environments on the long-term performance of sea defences. In order to reduce the risk of wave run-up and overtopping caused by rising sea level and to maintain the present-day allowances for wave run-up height and overtopping discharge, the future necessary increase in crest level of existing structures is investigated. Various critical failure mechanisms are considered for reliability analysis, i.e., erosion of crest by wave overtopping, failure of seaside revetment, and internal erosions within earth sea dykes. The time-dependent reliability of sea dykes is analysed to give probability of failure with time. The results for an example earth dyke section show that the necessary increase in crest level is approximately double of sea level rise to maintain the current allowances. The probability of failure for various failure modes of the earth dyke has a significant increase with time under future hydraulic conditions.

• 마이크로전자및패키징학회지
• /
• 제20권4호
• /
• pp.1-6
• /
• 2013

Recently, various types of flexible devices such as flexible displays, batteries, e-skins and solar cell panels have been reported. Most of the researches focus on the development of high performance flexible device. However, to realize these flexible devices, the long-term reliability should be guaranteed during the repeated deformations of flexible devices because the direct mechanical stress would be applied on the electronic devices unlike the rigid Si-based devices. Among various materials consisting electronics devices, metal electrode is one of the weakest parts against mechanical deformation because the mechanical and electrical properties of metal films degrade gradually due to fatigue damage during repeated deformations. This article reviews the researches of fatigue behavior of thin metal film, and introduces the methods to enhance the reliability of metal electrode for flexible device.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 A
• /
• pp.452-454
• /
• 2003

$SF_6$ gas has been increasingly used as the insulating and arc-suppressing medium in switchgears which are used as the protection devices of power system. Nowadays, most of power companies adopted the $SF_6$ gas-type load break switch for increasing the reliability of distribution network by its superior durability against external environmental condition, in substitution for air-type and oil-type switches. But, it is important to establish the general estimation process for the testing and estimation for long-term reliability. Accordingly, this paper presents the reliability testing method for $SF_6$ gas load break switch which is based on the analysis of the failure mode and the statistics.

• Smart Structures and Systems
• /
• 제20권1호
• /
• pp.11-22
• /
• 2017

The long-term effect of ambient temperature on bridge strain is an important and challenging problem. To investigate this issue, one year data of strain and ambient temperature of a long-span cable-stayed bridge is studied in this paper. The measured strain-time history is decomposed into two parts to obtain the strains due to vehicle load and temperature alone. A linear regression model between the temperature and the strain due to temperature is established. It is shown that for every $1^{\circ}C$ increase in temperature, the stress is increased by 0.148 MPa. Furthmore, the extreme value distributions of the strains due to vehicle load, temperature and the combination effect of them during the remaining service period are estimated by the average conditional exceedance rate approach. This approach avoids the problem of declustering of data to ensure independence. The estimated results demonstrate that the 95% quantile of the extreme strain distribution due to temperature is up to $1.488{\times}10^{-4}$ which is 2.38 times larger than that due to vehicle load. The study also indicates that the estimated extreme strain can reflect the long-term effect of temperature on bridge strain state, which has reference significance for the reliability estimation and safety assessment.

• 한국조리학회지
• /
• 제16권3호
• /
• pp.188-204
• /
• 2010

본 연구에서는 국내 외식업체의 와인구매담당자, 즉 소믈리에, 매니저 등을 대상으로 고객장기 지향성에 긍정적으로 영향을 미치는 관계마케팅 요인을 파악함과 동시에 장기지향성이 형성되는 과정에서 관계의 질인 신뢰와 몰입의 역할을 규명함으로써 내수 경기침체와 치열한 경쟁으로 인해 어려움을 겪고 있는 와인공급업체의 영업활성화를 위한 마케팅 전략 수립에 도움을 주고자 함이다. 설문조사는 2010년 1월 15일부터 2월 13일까지 30일간 실시하였으며, 서울 시내 파인다이닝 레스토랑, 캐주얼 다이닝 레스토랑, 와인바 등의 와인구매담당자를 대상으로 하였다. 자료의 처리는 SPSS 15.0과 AMOS 7.0 통계패키지를 사용하여 빈도분석, 신뢰도 분석, 확인요인분석, 경로분석을 사용하였다. 그 결과, 관계마케팅 요인 중에서 커뮤니케이션과 판매자 전문성 요인은 신뢰와 정서적 몰입을 통하여 장기지향성에 긍정적인 영향을 미치는 것으로 나타났다.

• 한국기록관리학회지
• /
• 제19권4호
• /
• pp.1-33
• /
• 2019

전자기록 장기보존의 핵심은 전자기록이 최초로 생성되고 활용되었던 본래의 기능적 속성과 모습 등을 담고 있는 비트스트림을 오랫동안 그대로 유지하는 것이다. 대부분 국내외 주요 아카이브기관들은 경제적, 기술적인 측면을 고려하여 원본의 비트스트림을 담고 있는 포맷의 안정성, 신뢰성에 따라 새로운 포맷으로의 변환을 허용하는 마이그레이션을 주전략으로 채택하고 있다. 그러나 전자기록 유형이 다양해지고 범위가 확장됨에 따라 마이그레이션 단일 전략은 다양한 문제점들을 발생시키고 있다. 그러므로 본 연구에서는 클라우드 컴퓨팅 기술을 활용하여 전자기록의 본래의 기능적 속성과 모습을 담고 있는 비트스트림을 변경하지 않으면서, 전자기록이 생산 활용된 시스템 및 응용 환경까지 재생산하는 에뮬레이션 전략의 적용 가능성을 검토하고자 한다.

• 한국환경복원기술학회지
• /
• 제22권1호
• /
• pp.73-84
• /
• 2019

In this research, it is a basic study to investigate the population of birds using UAVs. The research area is Ardeidae species(ASP) habitat and has long-term monitoring. The purpose of the study is to compare the ASP populations which analyzed ground observational survey and UAVs imagery. We used DJI's Mavic pro and Phantom4 for this research. Before investigating the population of ASP, we measured the escape distance by the UAVs, and the escape distances of the two UAVs models were statistically significant. Such a result would be different in UAV size and rotor(rotary wing) noise. The population of ASP who analyzed the ground observation and UAVs imagery count differed greatly. In detail, the population(mean) on the ground observation was 174.9, and the UAVs was 247.1 ~ 249.9. As a result of analyzing the UAVs imagery, These results indicate that the lower the UAVs camera altitude, the higher the ASP population, and the lower the UAVs camera altitude, the higher the resolution of the images and the better the reading of the individual of ASP. And we confirmed analyzed images taken at various altitudes, the individuals of ASP was not statistically significant. This is because the resolution of the phantom was superior to that of mavic pro. Our research is fundamental compared to similar studies. However, long-term monitoring for ASP of South Korea's by ground observation is a barrier of the reliability of the monitoring result. We suggested how to use UAVs which can improve long-term monitoring for ASP habitat.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
• /
• pp.147-148
• /
• 2001

The construction of reliability evaluation according to their fields was promoted under the supervision of Agency for Technology and Standards for establishing the relevant institution & infrastructure that can fundamentally solve the reliability problems, the biggest obstruction when the developed electric components & materials come into the market. This paper describes the criterion of reliability evaluation and the evaluation facilities for the purpose of heightening the reliability of composite insulator estimated as the new material among the electric components & materials. We will understand the criterion of reliability evaluation with two parts as the performance evaluation based on various kinds of standards (especially IEC) and as the long-term reliability evaluation utilizing the accelerated aging & flashover test methods. Therefore we aim for constructing the criterion of reliability evaluation as the foundation for evaluation so as to support the industrial group based on KERI facilities.

• KIEE International Transactions on Power Engineering
• /
• 제5A권1호
• /
• pp.62-69
• /
• 2005

The optimal design of transmission system expansion planning is an important part of the overall planning task of electric power system under competitive electricity market environments. One of main keys of the successful grid expansion planning comes from optimal reliability level/criteria decision, which should be given for constraint in the optimal expansion problem. However, it's very difficult to decide logically the optimal reliability criteria of a transmission system as well as generation system expansion planning in a society. This paper approaches a methodology for deciding the optimal reliability criteria for an optimal transmission system expansion planning. A deterministic reliability criteria, BRR (Bus Reserve Rate) is used in this study. The optimal reliability criteria, BRR/sup */, is decided at minimum cost point of total cost curve which is the sum of the utility cost associated with construction cost and the customer outage cost associated with supply interruptions for load considering bus reserve rate at load buses in long term forecasting. The characteristics and effectiveness of this methodology are illustrated by the case study using IEEE-RTS.

• 보건행정학회지
• /
• 제16권1호
• /
• pp.95-116
• /
• 2006

According to rapid increase of the population of senior citizens, there has been growing concern of Long-Tenn Care(LTC) services recently. Long-Tenn Care services, however, haven't been established systematically in Korea and the supply of LTC services is not sufficient despite the increase in the current social demand. This study aims to estimate the 'Willingness to Pay(WTP)' for LTC insurance which the government plans to introduce by means of social insurance, using Contingent Valuation Method(CYM). In addition, this study analyzes the factors affecting WTP for LTC insurance. An interview survey was carried out to derive WTP for LTC from 450 people who lived in Seoul aged 20 and above during the period from 16th to 21st of June 2003. Double-Bounded Dichotomous Choice Method was applied among several CVMs available to estimate both use value and no-use value of goods. There was pilot survey carried out prior to the main survey. The results show that the average monthly. WTP for LTC provided in home and residential setting is 18,192Won and 19,293Won, respectively. In the case of home care, WTP goes higher depending on reliability of LTC insurance policy and need for LTC insurance, as well as marital status, education and average monthly income. On the contrary, WTP is conversely affected by higher age and higher bids. In the case of institutional care, the factors affecting WTP are similar to those of home care, except age. This study followed NOAA's suggestions generally and the value derived through survey could be reliable. However, there can be the least bias in the process of survey because the CVM should be used under the supposed circumstances. Despite those limitations, it can be concluded that the amount the citizens are willing to pay for LTC is high enough to meet the costs needed to provide LTC.