• Structural Engineering and Mechanics
• /
• v.38 no.5
• /
• pp.651-674
• /
• 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.

• Journal of Information Technology Services
• /
• v.16 no.2
• /
• pp.61-83
• /
• 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
• /
• v.55 no.5
• /
• pp.979-999
• /
• 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.

• The Journal of Fisheries Business Administration
• /
• v.38 no.3
• /
• pp.89-108
• /
• 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)
• /
• v.15 no.12
• /
• pp.4567-4583
• /
• 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
• /
• v.17 no.3
• /
• pp.905-912
• /
• 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.

• International Journal of Highway Engineering
• /
• v.18 no.4
• /
• pp.9-18
• /
• 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.

• Therapeutic Science for Rehabilitation
• /
• v.10 no.1
• /
• pp.115-127
• /
• 2021

Objective : The purpose of this study was to investigate the effect of telerehabilitation on executive function, activities of daily living, instrumental activities of daily living, and occupational performance in stroke patients. Methods : The participants of this study were 30 outpatients with stroke residing in community. Both groups underwent the intervention 3 times a week for a total of 18 sessions. For the experimental group telerehabilitation was administered at home to only fifteen participants in the experimental group schedule, and it was supervised by the caregiver. Fifteen people in the control group underwent only the traditional occupational therapy. Executive function and instrumental activities of daily living were evaluated using the Korean version of the Executive Function Performance Test (EFPT-K). The basic daily activities of living were assessed using the Modified Barthel Index (MBI). The Canadian Occupational Performance Measure (COPM) was used to evaluate the client-centered occupational performance. Results : After the intervention, the experimental and control groups showed improvements in executive function, instrumental activities of daily living and occupational performance. Occupational performance improved more significantly in the experimental group than in the control group. Conclusion : Telerehabilitation and occupational therapy positively affect executive function, instrumental activities of daily living and occupational performance of patients with stroke. We suggest that telerehabilitation combined with occupational therapy is more effective in improving the occupational performance of stroke patients.

• The Korean Journal of Rehabilitation Nursing
• /
• v.13 no.2
• /
• pp.161-170
• /
• 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.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1528-1533
• /
• 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.