• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.597-601
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• 2005

Korea Railroad Research Institute(KRRI) developed the Driverless Rubber Tired Korea-AGT(Model: K-AGT) from 1999 to 2004. We have finished the safety and performance tests of K-AGT. Data obtained from this testing can be used to evaluate the growth of reliability. The most widely used traditional growth tracking model is included as IEC International standard. With the tracking model all corrective actions are incorporated during test, called test-fix-test. In the test-fix-test strategy problem modes are found during testing and corrective actions for these problems are incorporated during testing. In this paper, we demonstrated reliability analysis using growth model of driverless rubber tired K-AGT system to prove reliability of development system. Therefore, we introduce the well-known NHPP model and analyze a reliability growth using ReliaSoft's RGA software.

• Journal of Information Technology Services
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• v.16 no.2
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• pp.85-96
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• 2017

The revised "Software Industry Promotion Law" has been effective from 2013. This law is to be basis of the domestic public information sector and increases the opportunities for small and medium-sized firms in participating the public IT projects. The shortcomings of this law may be the increase of the risk and the decrease of quality of projects. These suggest that the competencies of project manager (PM) s are critical. Also, in general, an SI (System Integration) project is a one that provides a customer with a customer-tailored system for system integration. Particularly, in an SI project involved in a public institution or a large corporation, the ripple effect of success or failure of a project is becoming greater as the system requires higher cost and more time due to high complexity and large scale. One of the solutions to address these problems is to investigate the competencies of a PM. Thus, in this paper, we derived the major competencies using the RGT (Repertory Grid Technique) and categorized the resultant constructs using the content analysis. In addition, we analyzed the level of importance of competencies by applying the AHP (Analytic Hierarchy Process). The conclusion was that Problem-solving Skill and Leadership were the most important competencies of a project manager.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.223-232
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• 2023

The Work-Study parallel program has been promoted as a key policy to resolve the mismatch between industrial sites and school education and realize a competency-centered society, and as of December 2022, 16,664 companies participated in the training. Learning companies play a very important role as education and training supply organizations that conduct field training. In this study, for the evaluation of learning companies participating in work-study program, the authors derive important factors that determine the quality of on-site education and training by analyzing the cognitive structure of experts in charge of the company and present evaluation indicators for learning enterprises. Therefore, it is intended to lay the foundation for promoting the quality of work-study parallel program.

• Journal of Astronomy and Space Sciences
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• v.38 no.4
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• pp.217-227
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• 2021

In this study, we describe an analytical process for designing a low Earth orbit constellation for discontinuous regional coverage, to be used for a surveillance and reconnaissance space mission. The objective of this study was to configure a satellite constellation that targeted multiple areas near the Korean Peninsula. The constellation design forms part of a discontinuous regional coverage problem with a minimum revisit time. We first introduced an optimal inclination search algorithm to calculate the orbital inclination that maximizes the geometrical coverage of single or multiple ground targets. The common ground track (CGT) constellation pattern with a repeating period of one nodal day was then used to construct the rest of the orbital elements of the constellation. Combining these results, we present an analytical design process that users can directly apply to their own situation. For Seoul, for example, 39.0° was determined as the optimal orbital inclination, and the maximum and average revisit times were 58.1 min and 27.9 min for a 20-satellite constellation, and 42.5 min and 19.7 min for a 30-satellite CGT constellation, respectively. This study also compares the revisit times of the proposed method with those of a traditional Walker-Delta constellation under three inclination conditions: optimal inclination, restricted inclination by launch trajectories from the Korean Peninsula, and inclination for the sun-synchronous orbit. A comparison showed that the CGT constellation had the shortest revisit times with a non-optimal inclination condition. The results of this analysis can serve as a reference for determining the appropriate constellation pattern for a given inclination condition.

• Journal of Korean Library and Information Science Society
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• v.54 no.3
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• pp.249-270
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• 2023

The purpose of this study is to identify the characteristics of school library services using the RGT (repertory grid technique), and to examine whether there are differences in the perceptions and internal experiences of school library services between human resources (librarian teachers, subject teachers, and librarians). I used indicators such as element intensity, construct extremity, discrepant constructs, and implicative dilemmas to analyze the characteristics of school library services. The elements of the repertory grid were set to 9, and 14 constructs were set through focus group interviews with 3 librarian-teachers. The GRIDCOR 6.0, which can be accessed online, was used to complete the repertory grid for 30 graduate students of the College of Education, and 6 of them were selected and analyzed, considering the demographic characteristics. From the perspective of element intensity, it was found that the following school library services are important and influential: resource management, teacher-librarian collaboration, and reading and information counseling services. The clarity of one's role, the actual performance, and self-regulatory ability were ranked high from the perspective of constructs intensity.

• Journal of Life Science
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• v.23 no.1
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• pp.84-94
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• 2013

The cytotoxicity of coffee-like green tea (CLGT) was determined in a human breast cancer cell line, MCF-7; a human prostate cancer cell clone, PC-3; a human neuroblastoma cell line, SK-N-SH; and a rat cardiomyoblast cell line, H9c2, with reference to green tea leaves (GTL). The CLGT was prepared by roasting the GTL for 60 min at $240^{\circ}C$ in a temperature-controlled frying pan. The CLGT preparation imitated the flavor and taste characteristics of coffee fairly well according to sensory analysis. The CLGT preparation had no adverse cytotoxic effects on the cancer cells or the normal cells compared to GTL. No significant change in the antioxidant activity was seen in the CLGT preparation compared to that of GTL. The amount of total protein, sugar, and phenolic compounds was reduced in the preparation relative to those in GTL, a fact that might explain the coffee-like flavor and/or taste characteristics of the CLGT preparation. These results suggest that CLGT prepared by roasting GTL for 60 min at $240^{\circ}C$ does not show any adverse effects on cancer cells and normal cells compared to GTL. They imply that CLGT could be safe for human consumption.