• 터널과지하공간
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• 제23권6호
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• pp.457-469
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• 2013

국내 100여개 지역에서 측정된 460개 현지응력자료를 종합 분석하여 국내의 광역적 현지응력 분포 패턴을 분석하고, 심도-응력 및 심도-측압계수 관계식을 제시하였다. 이와 함께 한반도의 지질시대별 고응력장 변화와 최근의 지진 메카니즘에 의한 응력장 추정 결과를 통합하여, 한반도지역의 응력장 분포 패턴인 한국응력지도(Korea Stress Map)를 작성하였다. 세계의 심도-응력 관계식들과 비교를 통해, 본 연구에서 도출된 관계식의 적합성과 수 km 심도에의 유추 적용성을 확인하였다. 그리고 세계응력지도(World Stress Map)과 함께 동북아시아지역의 응력장 패턴을 분석하였다.

• 터널과지하공간
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• 제29권6호
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• pp.425-438
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• 2019

본 연구에서는 일정한 방향의 층리가 발달한 퇴적암에 굴착된 지하철 병설터널을 모델링하여 축소모형 실험을 실시하였다. 연구대상 터널의 규격은 6.2 m×6.8 m이고 필러 폭은 4 m이다. 차원해석을 통해 현장암석에 적합한 모형재료를 선정하였고, 이를 사용하여 이방성 모형시험체를 제작하였으며 이축압축시험을 통해 터널의 파괴 및 변형거동을 알아보았다. 모형시험체에 하중을 증가시킴에 따라 필러의 중앙부에서 병설터널 사이를 가로지르는 최초의 균열이 발생하였고, 터널 천정부와 바닥부에서도 점차 파괴가 진행되었다. 필러부의 모든 균열은 기존의 층리면을 따라 발생하여 암반의 층리면이 필러 파괴의 주요 원인으로 나타났다. 또한, FLAC의 유비쿼터스 절리모델을 사용하여 실험 조건에 대한 수치해석을 실시함으로써 실험의 결과를 검증해 보았다. 여기서 얻어진 소성영역의 분포경향은 모형실험의 결과와 대체로 부합하여 실험의 신뢰성을 확인하였다.

• 한국물환경학회지
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• 제20권6호
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• pp.589-596
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• 2004

In this study, the reduction rates of nutrients were suggested to prevent eutrophication on the Hwaong reservoir in the year of 2008 and 2012. With EPA's WASP6 model, future water quality were simulated. In 2008, T-N would be 1.36mg/L and T-P 0.100mg/L on average. ; In 2012, T-N 2.66mg/L and T-P 0.128mg/L. With all the water quality management plans that the government authorities are carrying out, these results indicate that the reservoir would be reach the eutrophic or hypertrophic state according to the Vollenweider's trophic states. Therefore, the Hwaong reservoir requires additional plans for nutrients management. Here, the target water quality to prevent eutrophication of the reservoir sets into mesotrophic state ; T-N 0.475mg/L and T-P 0.02mg/L.(median of Vollenweider index for mesotropphic state) The reduction rates of nutrients on Namyang and Eoeun streams were estimated with uniform treatment method to meet the goal. The results showed that nutrients from two streams should be reduced up to 78% in 2008, and 84% in 2012. Since the ratio of T-N/T-P would be higher than 16 at target years, T-N was not considered as the limiting factor and was not reduced.

• 한국물환경학회지
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• 제25권6호
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• pp.849-854
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• 2009

Pollutant unit load (unit-load) reported by Ministry of Environment (MOE) in 1995 has been a useful method for watershed management and environmental policy decision. The unit-load has been estimated using effective rainfall ratio method. However, reliability of unit-load determined by the method has been criticized especially for paddy field and upland conditions. In this paper the unit-load of paddy field estimated by effective rainfall ratio method was compared with continuous monitoring data. Annual loads was simulated by the method choosing 5~6 storm events randomly from whole events collected. Probability distribution of difference between results by the method and measured data was investigated. The results showed that unit-load derived by the method was generally lesser than measured unit-load and showed wide variations. Therefore, unit-load estimation of paddy fields by effective rainfall ratio method need caution.

• 대한수의학회지
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• 제50권1호
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• pp.43-48
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• 2010

Animal disease surveillance system, defined as the continuous investigation of a given population to detect the occurrence of disease or infection for control purposes, has been key roles to assess the health status of an animal population and, more recently, in international trade of animal and animal products with regard to risk assessment. Especially, for a system aiming to determine whether or not a disease is present in a population sensitivity of the system should be maintained high enough not to miss an infected animal. Therefore, when planning the implementation of surveillance system a number of factors that affecting surveillance sensitivity should be taken into account. Of these parameters sample size is of important, and different approaches are used to calculate sample size, usually depending on the objective of surveillance systems. The purpose of this study was to evaluate the sensitivity of the current national serological surveillance programs for four selected bovine diseases assuming a specified sampling plan, to examine factors affecting the probability of detection, and to provide sample sizes required for achieving surveillance goal of detecting at least an infection in a given population. Our results showed that, for example, detecting low level of prevalence (0.2% for bovine tuberculosis) requires selection of all animals per typical Korean cattle farm (n = 17), and thus risk-based target surveillance for high risk groups can be an alternative strategy to increase sensitivity while not increasing overall sampling efforts. The minimum sample size required for detecting at least one positive animal was sharply increased as the disease prevalence is low. More importantly, high reliability of prevalence estimation was expected with increased sampling fraction even when zero-infected animal was identified. The effect of sample size is also discussed in terms of the maximum prevalence when zero-infected animals were identified and on the probability of failure to detect an infection. We suggest that for many serological surveillance systems, diagnostic performance of the testing method, sample size, prevalence, population size, and statistical confidence need to be considered to correctly interpret results of the system.

• 한국측량학회지
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• 제22권4호
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• pp.339-347
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• 2004

본 연구에서는 택지조성공사가 실시되고 있는 대규모 현장을 대상으로 절$.$성토부 풍화암의 정확한 토량환산 계수를 산정하고자 한다. 이를 위해, 먼저 대상지 내의 절 성토부 각각 20개소를 굴착하고 굴착 후의 체적을 계산하였다. 그 결과, 교차에 대한 체적의 상대정확도는 평균 0.5%로 산출되었다. 또한, 계산된 체적에 의한 습윤 단위중량과 실내토질시험에 의한 함수비를 이용하여 정확한 토량환산계수를 산정하였다. 산정된 토량환산계수를 모래치환법에 의한 건조단위중량시험에 의해 결정된 토량환산계수와 비교 $.$분석한 결과, 미소한 차이를 나타내었다. 이는 불규칙한 굴착부분의 체적측정을 정밀수치사진측량기법을 적용하였으므로 현장시험의 신뢰성이 높고 토량환산계수 산정을 위한 합리적인 설계방법이라 판단된다.

• 대한기계학회논문집A
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• 제35권10호
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• pp.1229-1235
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• 2011

신뢰성이 가장 우수한 프레팅 피로손상 파라미터를 찾아내기 위해 알루미늄 합금 A7075-T6 을 대상으로 피로시험을 수행하였다. 시편 표면에 홈을 가공하여 패드 접촉압력에 따라 패드-시편 접촉면에서 프레팅 피로균열이 발생하거나 또는 홈에서 일반 피로균열이 발생할 수 있게 하였다. 광학현미경을 이용하여 균열의 발생위치와 방향을 측정하고, 문헌에서 가장 많이 사용되는 프레팅 피로손상 파라미터들의 신뢰성을 평가하였다. 파라미터 값과 최대손상평면 방향을 산출하는데 필요한 응력과 변형률 자료는 유한요소해석으로 산출하였다. 전단모드 피로파손을 가정하는 Fatemi-Socie 파라 미터와 McDiarmid 파라미터가 가장 신뢰성이 높은 것으로 판명되었다.

• 보건행정학회지
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• 제16권1호
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• pp.95-116
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• 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.

• 한국구조물진단유지관리공학회 논문집
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• 제15권5호
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• pp.113-123
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• 2011

LCC 분석은 비용평가만을 위한 개별적인 방법이 아닌 가치 개선을 위해 기능평가와 상호 연계되어 이루어지는 방법이다. 점차 LCC 분석의 정확성은 높아지고 있으나 비교적 최근에 개발 적용되어진 재료나 형식들에서는 공용기간이 확보되지 않아 여전히 유지관리 이력을 추정하기가 어려워 신뢰도가 떨어진다. 이런 배경으로 본 연구는 유지관리 프로파일을 설정하기 어려운 대안들에 대해서 기능적인 증감사항이 비용과 연계되어 분석되어지는 LCC 방법론을 제시하고자 한다. 최근 강상판 교면포장은 중차량과 교통량의 증가로 소성변형 등 문제점이 발생하여 기존의 포장을 대체할 수 있는 새로운 혼합물포장의 개발이 활발히 이루어지고 있다. SMA, Guss 및 PSMA 포장을 사례로 들어 대안 간에 비교된 성능척도가 상대평가계수로써 유지관리 프로파일 항목에 포함되어 LCC 분석이 이루어졌다.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권10호
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• pp.435-442
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• 2006

One of the most important topics about the safety of electrical and electronic system is the reliability of the wiring system. The Time-Frequency Domain Reflectometry(TFDR) is a state-of-the-art system for detecting and estimating of the fault on a wiring. In this paper, We've considered the load resistance measurement on a coaxial cable using TFDR in a way of expanded application. The TFDR system was built using commercial Pci extensions for Instrumentation(PXI) and LabVIEW. The proposed real time TFDR system consisted of the reference signal design, signal generation, signal acquisition, algorithm execution and results display part. To implement real time system, all of the parts were programmed by the LabVIEW which is one of the graphical programming languages. Using the application software implemented by the LabVIEW, we were able to design a proper reference signal which is suitable for target cable and control not only the arbitrary waveform generator in the signal generation part but alto the digital storage oscilloscope in the signal acquisition part. By using the TFDR real time system with the terminal resistor on the target cable, we carried out load impedance measurement experiments. The experimental results showed that the proposed system are able not only to detect the location of impedance discontinuity on the cable but also to estimate the load resistance with high accuracy.