• Structural Engineering and Mechanics
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• 제38권5호
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• pp.651-674
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• 2011

This paper presents a novel method for predicting the failure probability of structural or mechanical systems subjected to random loads and material properties involving multiple design points. The method involves Multicut High Dimensional Model Representation (Multicut-HDMR) technique in conjunction with moving least squares to approximate the original implicit limit state/performance function with an explicit function. Depending on the order chosen sometimes truncated Cut-HDMR expansion is unable to approximate the original implicit limit state/performance function when multiple design points exist on the limit state/performance function or when the problem domain is large. Multicut-HDMR addresses this problem by using multiple reference points to improve accuracy of the approximate limit state/performance function. Numerical examples show the accuracy and efficiency of the proposed approach in estimating the failure probability.

• 한국IT서비스학회지
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• 제16권2호
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• pp.61-83
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• 2017

It is well known that PMO (Project Management Office)s are effective for successful project performance. Since it takes a long time to develop PMO capability, many public organizations and companies that do not have internal PMOs are increasingly relying on outsourcing of PMO functions in order to introduce mature PMO capabilities in a short period of time. However, it is not verified yet whether outsourced PMO is more effective than internal PMO or not. The objective of this study is to verify the effectiveness of PMO outsourcing. There are many different definitions about PMO function, and even the same PMO function may have different effectiveness depending on the Industry. Thus, this study redefined the PMO functions and Project Performance based on the past studies, and conducted research by focusing on the ICT (Information and Communication Technology) industry. The ICT industry is an important industry economically and has been attracting global attention recently. This study is the first attempt to prove the effectiveness of outsourcing of PMO function in Korea. We found that PMO function outsourcing is effective for certain aspects of project performance, particularly technical support and infrastructure management. Overall, PMO outsourcing is usually more effective than internal PMO for improving project performance. The results of this study are expected to contribute to the development of PMO theories and practices.

• Structural Engineering and Mechanics
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• 제55권5호
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• pp.979-999
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• 2015

This paper proposes a novel reliability analysis method which computes reliability index, most probable point and probability of failure of uncertain systems more efficiently and accurately with compared to Monte Carlo, first-order reliability and response surface methods. It consists of Initial and Simulation steps. In Initial step, a number of space-filling designs are selected throughout the variables space, and then in Simulation step, performances of most of samples are estimated via interpolation using the space-filling designs, and only for a small number of the samples actual performance function is used for evaluation. In better words, doing so, we use a simple interpolation function called "reduced" function instead of the actual expensive-to-evaluate performance function of the system to evaluate most of samples. By using such a reduced function, total number of evaluations of actual performance is significantly reduced; hence, the method can be called Reduced Function Evaluations method. Reliabilities of six examples including series and parallel systems with multiple failure modes with truncated and/or non-truncated random variables are analyzed to demonstrate efficiency, accuracy and robustness of proposed method. In addition, a reliability-based design optimization algorithm is proposed and an example is solved to show its good performance.

• 수산경영론집
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• 제38권3호
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• pp.89-108
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• 2007

The purpose of the study are summarized as follows: First, it has researched the new functions of middleman in Fisheries Port Market. Second, the new functions which middleman have to perform in Fisheries Port Market consist of the origin function, marketing function, logistics function. The origin function consists of the discrimination of fish species and freshness, making the price by auction, financing, etc. Marketing function consists of various species assortment from not only fisheries port market but also non fisheries port market as frozen and import fish markets, finding the new selling markets as not broker but wholesaler, making the price and margin non through the action, processing, etc. Logistics function consist of fish stock, delivery Third, it has recognized the upcoming important problems by building up the new functions as middleman in Fisheries port Market. This study has used a questionnaire to verify 3 hypotheses. Research model, factor analysis, regression analysis. The result of this study are summarized as follows: The origin function influences positively on the effectiveness of middleman's performance in Fisheries port Market. Marketing function influences positively on the effectiveness of middleman's performance. However, logistics function did not directly influences on the effectiveness of middleman's performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권12호
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• pp.4567-4583
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• 2021

This study proposes an analytical approximation algorithm based on extreme value theory (EVT) for the inverse of the power of the incomplete Gamma function. First, the Gumbel function is used to approximate the power of the incomplete Gamma function, and the corresponding inverse problem is transformed into the inversion of an exponential function. Then, using the tail equivalence theorem, the normalized coefficient of the general Weibull distribution function is employed to replace the normalized coefficient of the random variable following a Gamma distribution, and the approximate closed form solution is obtained. The effects of equation parameters on the algorithm performance are evaluated through simulation analysis under various conditions, and the performance of this algorithm is compared to those of the Newton iterative algorithm and other existing approximate analytical algorithms. The proposed algorithm exhibits good approximation performance under appropriate parameter settings. Finally, the performance of this method is evaluated by calculating the thresholds of space-time block coding and space-frequency block coding pattern recognition in multiple-input and multiple-output orthogonal frequency division multiplexing. The analytical approximation method can be applied to other related situations involving the maximum statistics of independent and identically distributed random variables following Gamma distributions.

• Journal of the Korean Data and Information Science Society
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• 제17권3호
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• pp.905-912
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• 2006

Support vector classification(SVC) provides more complete description of the linear and nonlinear relationships between input vectors and classifiers. In this paper we propose to solve the optimization problem of SVC with a modified hinge loss function, which enables to use an iterative reweighted least squares(IRWLS) procedure. We also introduce the approximate cross validation function to select the hyperparameters which affect the performance of SVC. Experimental results are then presented which illustrate the performance of the proposed procedure for classification.

• 한국도로학회논문집
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• 제18권4호
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• pp.9-18
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• 2016

PURPOSES : This study aimed to evaluate the performance of pavement management works and to develop a function for estimating the level of service (LOS) and cost of service (COS) for the systematic and quantitative management of pavement performance in the public sector. METHODS : The International Roughness Index (IRI) was used as the performance index for pavement management. Long-term pavement performance data for a period of 7 years (2007-2014) collected by the National Highway Pavement Management System and historical maintenance budget data published by the South Korean government were used to develop the LOS-COS function. Based on the function, a model for estimating the appropriate budget as well as the network conditions was suggested. RESULTS : There was high degree of correlation between pavement performance and the investment level (R = - 0.74). The developed LOS-COS function suggested that the unit cost to improve the network IRI to 1 m/km was 32.6 billion KRW. Further, the maintenance costs normalized with respect to the LOS levels were LOS-A = 88.2 billion KRW, LOS-B = 55.6 billion KRW, and LOS-C = 23.0 billion KRW. CONCLUSIONS : This study proposes a simple way of developing a LOS-COS function. It also shows how to develop a network budget demand and condition estimation model using the LOS-COS function. In addition, it is the first attempt to evaluate the road maintenance budget in South Korea. It is expected that these results will help in the negotiations between the road managers and budget makers.

• 재활치료과학
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• 제10권1호
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• pp.115-127
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• 2021

목적 : 본 연구는 원격재활에 기반 한 작업치료가 뇌졸중 환자의 실행기능, 일상생활수행, 작업수행에 영향을 미치는지 알아보고자 한다. 연구방법 : 지역사회에 거주하며, 재활병원에 외래로 통원하는 환자 30명을 실험군과 대조군에 각각 15명씩 무작위 할당하여 연구를 진행하였다. 실험군 집단과 실험군의 중재는 모두 주 3회 18회기로 실시하였다. 실험군 15명에게는 전통적 작업치료와 함께 더불어 가정에서의 원격재활 기반 프로토콜을 적용하였다. 대조군 15명은 전통적 작업치료만 실시하였다. 실험 참가자의 실행기능과 수단적 일상생활수행은 실행기능 수행평가 한국판(Executive Function Performance Test Korean version; EFPT-K)으로 측정하였고, 기본적 일상생활활동은 수정된 바델 지수(Modified Barthel Index; MBI), 작업수행은 클라이언트 중심의 과제수행을 측정하기 위해서 캐나다 작업수행 측정(Canadian Occupational Performance Measure; COPM)을 이용하였다. 결과 : 중재 후 실험군과 대조군은 모두 실행기능, 수단적 일상생활활동, 작업수행에서 유의한 변화가 있었으나(p<.05), 기본적 일상생활수행에서는 유의한 변화가 없었다. 집단 간 비교에서는 작업수행에서만 실험군이 대조군보다 유의하게 더 많은 증진이 나타났다. 결론 : 원격재활과 작업치료는 뇌졸중 환자의 실행기능, 수단적 일상생활수행, 작업수행의 향상에 긍정적인 영향을 미친다. 작업치료에 병행된 원격재활은 뇌졸중 환자의 작업수행에 추가적인 효과가 있음을 근거로써 제시한다.

• 재활간호학회지
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• 제13권2호
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• pp.161-170
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• 2010

Purpose: This study was to confirm the influence of memory intensive training program on the elderly people's cognitive function, memory performance, and self-esteem. Method: Using a quasi-experimental or experimental design, 60 elderly aged over 60 years randomly assigned the experimental and control groups completed pretest-post evaluation. The experimental group participated in the memory intensive training program was offered to the participants in the experimental group for three weeks (2times/week). The t-test and $X^2$-test using SAS program. Results: 1) The cognitive function was significantly higher in the experimental group compared to that in the control group (t=3.26, p=.002). 2) The memory performance that included immediate word recall tasks, word recognition tasks and delayed word recall tasks was significantly higher in the experimental group than in the control group (t=5.30, p<.001). The experimental group showed significantly higher scores for memory performance than the control group (t=5.30, p<.001). 3) The self-esteem was higher in the experimental group than in the control group, but there was no significant difference between the two groups (t=1.94, p=.058). Conclusion: The Memory Intensive Training Program could be an effective intervention for improving cognitive function, and memory performance of the elderly people.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1528-1533
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• 2009

Infrastructure is provided to the user through long-term project period and large-scale working expenses. Existing facilities are getting old as time goes by. Accordingly, proper maintenance is required and generally more maintenance cost than initial invested cost is needed during life cycle. Therefore, a specific plan that just increases the value of facilities is required by evaluating performance of facilities and inputting minimum maintenance cost. Value engineering that increases the value of object by systemically analyzing Life Cycle Costs and function is actively promoted at the design phase of construction. These efforts can increase the performance of facilities at the maintenance phase of infrastructure. This study is to search how to evaluate the performance of Roadway by utilizing function analysis, as a core part of VE in the maintenance phase. In order to this a new evaluation criteria were proposed by adding an evaluation items to the existing criteria through the research of old documents, status of roadway maintenance and function analysis of VE. The results of this study may promote the effective performance evaluation to determine a resolution of roadway congestion in future. A succeeding study using the proposed evaluation criteria will be required.