• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.127-137
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• 2003

Contingency analysis is one of the most important tasks encountered by planning and operation of lafe scale power systems. This paper describes a new contingency analysis methods for small signal security assessment based on the eigen-sensitivity/perturbation of the electromechanical oscillation modes. The eigen-sensitivity/perturbation with respect to line suceptances and controller parameters can he used to find possible sources of the system instability, and to select contingency for small signal stability. Also, the contingency selection to identify critical generators for MW changes can be obtained by computing the relative movement of the system oscillation modes. The proposed algorithm has been successfully tested on the KEPCO systems which is comprised of 791-bus, 1575-branch and program PSS/E

• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.114-123
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• 2018

For conservation of biodiversity, we designate and manage the major areas that are habitats of organisms as ecosystem protected areas. It is necessary to evaluate the biodiversity of protected areas relatively in order to establish strategies to protect and secure the biodiversity of protected areas. In this study, we selected evaluation indicators by which we can compare objectively the biodiversity of protected areas corresponding to forest ecosystem, and applied them to Mt. Jiri and Mt. Bukhan National Parks. We reviewed literatures to select evaluation criteria. Frequently mentioned criteria and the structure of the forest which plays an importantrole of forest biodiversity were selected as the evaluation criteria. As the result, the selected evaluation indicators were 7-species diversity, species richness, evenness, rarity, disturbance species, indigenous species, and forest structure. In Mt. Jiri and Mt. Bukhan National Parks, species diversity were 3.492 and 2.943, species richness were 8.998 and 9.793, evenness were 0.849 and 0.680,rarity were 11.976 and 10.783, and disturbance species index were 0.214 and 0.357 respectively. Both national parks had abundant indigenous species and showed various forest physiognomies and stable 4-layer structure. It was found that crown density was higher in Mt. Jiri. Most indicators were implied high biodiversity in Mt. Jiri and Mt. Bukhan national parks.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.159-172
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• 2006

In this study, the series of Landsat TM/ETM+ images was acquired to extract land surface temperature for wide-area and executed geometric correction and radiometric correction. And the land surface temperature was extracted using NASA Model, and achieved the first correction by performing land coverage category for study area and applied characteristic emission rate. Land surface temperature which was acquired by the first correction was analyzed in correlation with Meteorological Administration's temperature data by regression analysis, and established correction formula. And I wished to improve accuracy of land surface temperature extraction using satellite image by second correcting deviations between two data using establishing correction formula. As a result, land surface temperature acquired by 1st and 2st correction could be corrected in mean deviation of about ${\pm}3.0^{\circ}C$ with Meteorological Administration data. Also, I could acquire land surface temperature about study area by higher accuracy by applying to other Landsat images for re-verification of study results.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.41-59
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• 2010

In this study, the indicators for evaluating the level of green growth in transportation are proposed. The authors reviewed the existing philosophies such as sustainable development and eco-efficiency and explained the differences between the philosophies and green growth. The planning hierarchy and indicator framework are proposed and the idea of indicators is also introduced. In order to decide the weighting value for objectives and targets, a questionnaire survey for transportation experts was conducted. The survey results show that low-carbon/environmentally-friendly development is the most important objective. In addition, the results reveal that transportation experts do not fully understand the concept of green growth and cannot differentiate the concept of green growth from that of sustainable development and eco-efficiency.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.118-129
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• 2013

Due to the recent surge in natural disasters, with rising social concerns, investment on research & development (R&D) project in natural disaster mitigation area is continuously increasing. However, current R&D performance management system of natural disaster mitigation area does not properly reflect characteristics and social ripple effects of R&D projects. It is indicated that mainly due to the current performance index consists of easy-quantification factors and the performance evaluation system adopts simple aggregation method. Therefore, the purpose of this study is to develop new performance evaluation system considering characteristics and social ripple effects of natural disaster mitigation R&D projects. To this ends, this study derived 3-dimensional performance measurement index through literature review and natural disaster mitigation R&D projects analysis. Finally, based on the derived performance measurement index, this study suggested new and effective performance evaluation system for natural disaster mitigation R&D projects.

• Journal of the Korean Society for information Management
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• v.35 no.1
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• pp.205-229
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• 2018

This study analyzed Korean university libraries' holdings of Western language books published in 2003 and 2013 using the KERIS union catalog with a view to investigating the changes in collection development of Western language books in the libraries. To do that, new collection indexes - holding h-index, CUI (Collection Uniqueness Index), and CCHR (Common Collection Holding Ratio) - were suggested, and they were used with basic indexes such as the number of titles, the number of books, and the number of books per title. The analysis reveals that compared to those published in 2003, the number of titles was decreased by 16.1% with those published in 2013, and the number of books dropped more sharply, by 42.2%. Also, in 2013, CCHR was decreased while CUI was increased. In terms of subject, among DDC main classes, 0XX (Generalities) showed the greatest decrease rate in both the number of titles and books because of the radical reduction of computer-related books. In terms of each library's holdings, the number of Western language books held by top libraries has been increased with those published in 2013.

• Phonetics and Speech Sciences
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• v.14 no.2
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• pp.87-99
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• 2022

A review regarding indicators used in Korean research is needed to develop a diagnostic marker system for Korean children with speech sound disorders (SSD). This literature review examined the research conducted to reveal the characteristics of children with SSD of unknown origin in Korea. The researchers in Korea used diverse variables as indicators to identify the natures of children with SSD. These included indicators related to external characteristics of speech sound and comorbid features other than external aspects of speech sound. The attention has been focused on specific indicators so far. This result implies that some indicators may still require closer study in various aspects due to their influence, and some may require more attention due to the limited number of research. This article argues that more research is necessary to comprehensively describe the unique characteristics of children with SSD of unknown origin and suggests a direction for future research regarding diagnostic markers and subtype classification of SSD. It also proposes potential diagnostic markers and a set of assessments for the subtype classification of SSD.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.107-114
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• 2018

In this study, the damage detection method is proposed for the rotational stiffness of connections in steel moment frames by using artificial neural network(ANN). The flexural moment of columns, natural frequencies, modeshapes are used for the input layer in ANN while the damage index, that signify the damage level, is used for the output layer in ANN. The 5-story steel moment frame as an example structure is used to generate the train and test data. Total number of damage scenarios considered is 829. From the results of application, it is shown that the proposed method can accurately estimate the location and level of damages.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.305-311
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• 2012

For the optimization of the fundamental natural frequency of stiffened cylindrical shells, simulations were performed for cylindrical shells that were stiffened with between one and five ring stiffeners. ANSYS 11.0 was used to simulate the optimization for the natural frequency. The Subproblem Approximation Method was applied as the optimization method. The design function of the optimization was the geometry of the T-shaped ring stiffener, and the constraint function was the maximum additional volume, constrained to a 10% increase. The objective function of the optimization was chosen to maximize the fundamental natural frequency. The performance index for optimal design was defined as the ratio of the natural frequency to the volume of the unstiffened and stiffened shells. The optimal performance index was obtained for the shell stiffened with three rings.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.206-214
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• 2020

This study analyzed the impact of direct and indirect subsidies on profitability in general hospitals in Korea. The data were collected from medical institution accounting information disclosure system of 270 general hospitals from 2016 to 2018. The analysis index used the ratio of net profit to business revenue for profitability, and Subsidies index the ratio of subsidies to business revenue(state subsidies for facility investment purposes, Fund related to essential business, research revenue and contribution revenue). According to the study, the ratio of state subsidies, which are direct subsidies, was very high at 57.30 percent for public institution hospitals. ratio of Fund related to essential business, which is a tax reduction effect with indirect subsidies, had the highest at 6.69 percent for Private University Hospitals. which are Indirect subsidies for deficit or operational assistance, research revenue ratio had the highest 2.8 percent for National University Hospitals, contribution revenue ratio had the highest 36.4 percent for public institutions. As a result of looking at the impact of subsidies on profitability, Nation University Hospitals had the lower the ratio of Fund related to essential business and the ratio of research revenue, the higher the net profit ratio of Business revenue. Medical Corporation Hospitals and Foundation Hospitals had the higher the ratio of Fund related to essential business to business revenues, the higher the net profit ratio of business revenue. These results mean that profitability may fluctuate depending on the utilization of funds related to essential business.