• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.103-114
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• 2003

This paper aims to propose a method that helps maintenance engineers to evaluate the damage states of bridge structure systems by using a Fuzzy Fault Tree Analysis. It may be stated that Fuzzy Fault Tree Analysis may be very useful for the systematic and rational fuzzy reliability assessment for real bridge structure systems problems because the approach is able to effectively deal with all the related bridge structural element damages in terms of the linguistic variables that incorporate systematically experts experiences and subjective judgement. This paper considers these uncertainties by providing a fuzzy reliability-based framework and shows that the identification of the optimum maintenance scenario is a straightforward process. This is achieved by using a computer program for LIFETIME. This program can consider the effects of various types of actions on the fuzzy reliability index profile of a deteriorating structures. Only the effect of maintenance interventions is considered in this study. However. any environmental or mechanical action affecting the fuzzy reliability index profile can be considered in LIFETIME. Numerical examples of deteriorating bridges are presented to illustrate the capability of the proposed approach. Further development and implementation of this approach are recommended for future research.

• Wind and Structures
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• 제24권3호
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• pp.223-247
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• 2017

By using numerical simulation, vast and detailed information and observation of the physics of flow over a train model can be obtained. However, the accuracy of the numerical results is questionable as it is affected by grid convergence error. This paper describes a systematic method of computational grid refinement for the Unsteady Reynolds Navier-Stokes (URANS) of flow around a generic model of trains using the OpenFOAM software. The sensitivity of the computed flow field on different mesh resolutions is investigated in this paper. This involves solutions on three different grid refinements, namely fine, medium, and coarse grids to investigate the effect of grid dependency. The level of grid independence is evaluated using a form of Richardson extrapolation and Grid Convergence Index (GCI). This is done by comparing the GCI results of various parameters between different levels of mesh resolutions. In this study, monotonic convergence criteria were achieved, indicating that the grid convergence error was progressively reduced. The fine grid resolution's GCI value was less than 1%. The results from a simulation of the finest grid resolution, which includes pressure coefficient, drag coefficient and flow visualization, are presented and compared to previous available data.

• 한국통신학회논문지
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• 제41권10호
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• pp.1221-1232
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• 2016

인터넷 주소의 수요가 급증하고 있지만 기존 IPv4 주소는 사실상 고갈상태이다. 따라서 IPv6로의 전환이 지속적으로 이루어지고 있는 가운데, IPv6의 실측 지표를 통해 IPv6 도입에 대한 체계적인 실태 파악의 필요성이 대두되었다. 본 연구에서는 국내 IPv6 사용도 실측 지표 개발을 위해 국내외 실측기법 및 사례들을 조사하고 기존 국내 실측지표에 대한 평가 및 검증을 통해 개선된 실측지표를 도출하며 각 지표에 대한 구현 방법을 제시한다.

• 한국항해항만학회지
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• 제41권5호
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• pp.287-296
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• 2017

The Formal Safety Assessment (FSA) is a structured and systematic methodology developed by the IMO, aimed at assessing the risk of vessels and recommending the method to control intolerable risks, thereby enhancing maritime safety, including protection of life, health, the marine environment and property, by using risk analysis and cost-benefit assessment. While the FSA has mostly been applied to merchant vessels, it has rarely been applied to a DP vessel, which is one of the special purpose vessels in the offshore industry. Furthermore, most of the FSA has been conducted so far by using the Fault Tree Analysis tool, even though there are many other risk analysis tools. This study carried out the FSA for safe operation of DP vessels by using the Bayesian network, under which conditional probability was examined. This study determined the frequency and severity of DP LOP incidents reported to the IMCA from 2001 to 2010, and obtained the Risk Index by applying the Bayesian network. Then, the Risk Control Options (RCOs) were identified through an expert brainstorming and DP vessel simulations. This study recommends duplication of PRS, regardless of the DP class and PRS type and DP system specific training. Finally, this study verified that the Bayesian network and DP simulator can also serve as an effective tool for FSA implementation.

• The Journal of Asian Finance, Economics and Business
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• 제6권2호
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• pp.9-13
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• 2019

The paper aims to investigate the performance of domestic Saudi Arabian ETFs. ETFs are investment vehicles in vogue. These instruments were the first levers for investors allowing them to enter some markets that have been highly protected or out of reach. Saudi Arabia, which has been promoted as an emerging country by MSCI, seeks to attract more foreign investors. The first ETFs were launched in the years 2010-2011. Even though their number has not increased since then, there is a desire to attract a large number of investors. We use premiums/discounts analysis, standard risk-return models, and tracking errors measurements to assess how closely their replicate the underlying benchmark based on monthly data. The results indicate that out of the three funds investigated two are slightly traded at premium, while the latter exhibit a price discount. However, tracking errors are at minimum for all funds suggesting that they track well the benchmark index. Further, the Jensen's model shows that alphas are negative or null, and betas capture largely the systematic risk which is consistent with index investing strategies. Finally, traditional risk-adjusted measures of performance are used to compare ETFs, and results exhibit negative ratios showing that portfolios achieve lower return than the risk-free rate.

• 보건행정학회지
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• 제2권1호
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• pp.1-16
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• 1992

This study compares the physician payment of national fee schedule for Korean Medical Insurance with that of the United States based on Resource Based Relative Value Scales (RBRVS) which Hsiao developed in 1988 for the Medicare reimbursement. Through the comparison of two fees schedules, this study is purposed to evaluate the appropriateness of relative values which assigned to each physician services of Korean fee schedule. A total of 264 physician services are selected for the comparison. The ratio of Korean schedule to RBRVS is selected as an index of appropriateness. It the score of index shows large variation among services, the relative value of Korean fee schedule is inappropriate with U.S. RBRVS which was developed recently. The Ratios of Korean schedule to RBRVS are widly variated ; the range of those is 8.1 to 379.3. In subgroups which are regrouped to controll systematic differences between two national fee schedules, these ratios are also variated. Services which are relatively less compensated are management/evaluation services, while services which are relatively more compensated are invasive and imaging services. By the way, the service classification of Korean fee schedule is unclear, specially in management/evalutaion services. Therefore, Korean Medical Insurance fee schedule should be modified to be more balanced and rational.

• 수산경영론집
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• 제53권4호
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• pp.27-49
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• 2022

This study focused on diagnosing and analyzing the level of sustainable development for each fishing communities by applying the sustainable development index in the fishing communities to support the policy of revitalizing the fishing communities. In terms of methodology, diagnostic indicators for rural areas were used through previous studies and literature surveys, and three categories, five fields and 27 indicators were finally selected through collecting opinions from experts. After deriving the weight for each indicator in detail, the final sustainable development index of the fishing communities was applied to fishing village fraternity. Based on the results of the analysis of the application of sustainable development cases in fishing communities, policy support should be implemented differentially according to regional decline factors and potential growth factors. In the population and social sector, it is necessary to consider ways to reduce population and reduce aging. In the industrial and economic sectors, fishing activation and systematic support for fishing-related industries should be provided. In the marine and built environment sector, the government's active project execution and budget support are required. In addition, it is expected to be used in various ways in the process of developing fishing communities and establishing revitalization plans that reflect the characteristics of the region.

• 무역학회지
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• 제45권4호
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• pp.25-43
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• 2020

This study mainly measures the level of trade facilitation in member countries along the "the Belt and Road" and discusses the impact of trade facilitation on bilateral trade. Based on the research results of domestic and foreign scholars, this study made a new systematic measuring system which covering 4 indicators and 15 subordinate indicators, to obtain the trade facilitation index. Based on the extended gravity model, this paper conducts a panel data, for more than 50 major trading members along the "the Belt and Road" during 2010~2017 as an example to empirically study the relationship between the trade facilitation level of major trading members and the volume of China's import and export trade. The results show that the level of trade facilitation among member countries is not high and the trade facilitation variable has positive value, indicating that the trade facilitation variable has positive effect on increasing bilateral trade. If the trade facilitation increases by 1% respectively, the bilateral trade level will increase by 0.98% separately. Finally, according to the regression results of four aspects of the trade facilitation index system, e-business development plays the most significant role in promoting trade facilitation.

• 가정간호학회지
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• 제31권1호
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• pp.66-76
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• 2024

Purpose: This study aimed to develop and evaluate an integrated management program to enhance self-efficacy, compliance with sick-role behaviors, symptom management, and biomarker indication in hemodialysis patients. Methods: The integrated management program was developed through a systematic review of literature, analysis of relevant online data, and expert validation. It comprised 480 min of video-based education delivered eight times over four weeks, supplemented by weekly phone consultations and text message support from a nurse. To evaluate the program's effectiveness, it was administered to 44 patients with hemodialysis in a single group in a pre-post test experimental study. Changes in self-efficacy, sick-role behavior compliance, dialysis symptom index, and biomarkers were assessed. Results: The program yielded statistically significant improvements in self-efficacy (t=-7.13, p<.001), sick-role behavioral compliance (t=-7.35, p<.001), dialysis symptom index (t=4.32, p<.001), and blood urea nitrogen levels (t=2.55, p=.014) among the participants. Conclusion: The integrated management program is an effective intervention for improving hemodialysis patients' self-efficacy, compliance with sick-role behaviors, and experience of symptoms. Additionally, it is considered an intervention with high clinical applicability and efficiency through video reproducibility.

• 한국지반공학회논문집
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• 제18권2호
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• pp.161-170
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• 2002

본 논문은 최적화기법을 이용하여 현장에서 수행된 피에조콘 소산시험의 초기 경향으로부터 평형간극수압과 지반의 강성지수$(=G/s_u)$를 역해석하는 기법에 관하여 기술하였다. 피에조콘 관입으로 인해 콘 주변에 발생된 초기 과잉간극 수압의 크기 및 분포, 그리고 연속된 간극수압 소산과정은 Randolph & Wroth(1979)가 제안한 해석적 해를 이용하여 지반의 강성지수의 함수로 표현되었다. 제안된 기법에서는 주어진 강성지수에 대해 정규화 된 이론 소산곡선과 평형간극수압으로 정규화 된 피에조콘 관측 소산곡선이 가장 일치하도록 하는 평형간극수압과 지반의 강성지수가 최적화기법을 이용하여 결정되었다. 제안된 기법을 압밀이 진행중인 지반에서 관측된 피에조콘 소산시험 결과(Tanaka & Sakagami, 1989) 해석에 적용하였고 역해석된 평형간극수압과 현장에서 관측된 평형간극수압의 크기를 비교하였다. 또한 제안된 기법으로 얻어진 지반의 강성지수와 평형간극수압을 바탕으로 수평압밀계수를 추정하였으며 일차원 압밀실험 결과와 비교하였다. 그 결과 제안된 기법이 지반에 잔류하는 평형간극수압의 크기를 매우 정확하게 예측함을 알 수 있었고 역해석 된 강성지수를 이용한 압밀계수의 추정이 타당함을 알 수 있었다. 또한 얻어진 강성지수의 변형 률수준에 관한 검토결과 피에조콘 해석을 위한 강성지수는 중간 또는 대변형 상태의 변형상태에 해당하는 값을 사용하는 것이 타당할 것으로 판단되었다.