• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1397-1405
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• 2017

As the introduction of wind power is steadily increasing, negative effects of wind power become more important. To operate a power system more reliable, the system operator needs to recognize the maximum required capacity of available generators for a certain period. For recognizing the maximum capacity, this paper proposes a methodology to determine an optimal reserve requirement considering wind power, for the certain period in the mid-term perspective. As wind speed is predicted earlier, the difference of the forecasted and the actual wind speed becomes greater. All possible forecast errors should be considered in determining optimal reserve, and they are represented explicitly by the proposed matrix form in this paper. In addition, impacts of the generator failure are also analyzed using the matrix form. Through three main stages which are the scheduling, contingency and evaluation stages, costs associated with power generation, reserve procurement and the usage, and the reliability cost are calculated. The optimal reserve requirement is determined so as to minimize the sum of these costs based on the cost/reliability analysis. In case study, it is performed to analyze the impact of wind power penetration on the reserve requirement, and how major factors affect it.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.16-21
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• 2012

The purpose of this study is to try to find the risk of roller(mixing mill) in working site. In order to achieve the purpose, accident analysis and survey was carried out. This analysis revealed that average of loss days is 334.3 by roller jamming accident and 229.2 by other causes. It means jamming accident entails serious bodily harm. According to our research, we realize that most of rollers have some risk of the jamming accidents. It is simply because the roll gap in the roller is not more than 10cm. It also does not meet minimum distance so as to avoid the risk for jamming accident by KS. Furthermore, 28% of rollers have only one switch and 40% of rollers have two switches operating emergence stop equipment so as to reduce the risk of jamming accidents. Therefore, we presume that it is very difficult to turn on the switch of emergence stop equipment when they confront the accident because most of engineers are working alone.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.28-36
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• 2012

Augmentation of existing EHV substations located in hilly terrain and at high altitude require many different considerations as compared to substations located in plain areas and at lower altitude. Owing to high altitude and steep terrain, meticulous engineering and preparations are required, considering the actual available space at the existing substation. Historical fault events too must be considered to enhance reliability and performance of the substation equipment. This paper proposes ways to augment the existing 2 banks of 20MVA, 220/66kV power transformers ($3{\times}6.67MVA$, single-phase) to $2{\times}50$/63MVA, 220/66kV power transformers to meet continuously increasing demand of the capital city over the next 20 years. Upgrading and augmentation of existing substations, especially the main transformers and associated equipment, require replacement with minimum or no disturbance to the existing power supply system. Considerations should also be made during engineering and design, the operational flexibilities, maintenance aspects, future expandability and value addition, in terms of reliability and space usage of the existing substation.

• Korean Management Science Review
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• v.19 no.2
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• pp.25-39
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• 2002

This study suggests a revised TAM (Technology Acceptance Model)-based performance evaluation model in MS (management science) education. Recently, many MS education programs are developed on the basis of computer and Internet communication technology. Previous researchers used TAM as an individual performance evaluation model, and proved that perceived usefulness and perceived ease of use are the substantive successful factors. This study provides a revised TAM-based conceptual framework for understanding what is involved in improving university MS education and what might be implied by conducting research on its improvement. It is argued in this research that three sets of forces and conditions have a direct and indirect impact on MS education ; first, each student has self efficacy and it is a critical determinant of behavior next, the use of Internet-based information system at MS education affects on the renewal of MS education : and finally, perceived usefulness and perceived ease of use have impacts on behavioral intention and actual system usage. This research concludes with suggestions for which direction this framework provides for future research on the premise and limits of efforts to renew MS education in university.

• Journal of Applied Reliability
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• v.11 no.4
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• pp.331-342
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• 2011

The transmission of tracked vehicles performs complex functions as steering, shifting, braking, etc. and the system level life time has been a key influenced by the number of sub-parts like as gear assembly, torque converter, clutches, bearings and so on. In particular, the mechanical type steering system in tracked vehicle has impact shock torques in steering shift and those kind of shock torques can effect on the durability of many sub-parts in power train system. The field failure modes of gear assembly, steering assembly and the bearings of output shaft appear as a very complex phenomenon. In this study, the actual failure, which may occur in field, of the transmission was investigated comprehensively and that the endurance test on the resulting output shaft bearing failure analysis and life assessment was performed. Life time test method used in this study, developed for the purpose of the internal usage, and under these testing techniques the impact of the each bearing damage, which used in tracked vehicle transmission left / right outputs of different structures, was analyzed.

• Asian Journal of Innovation and Policy
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• v.9 no.1
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• pp.12-35
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• 2020

Quality performance information has been regarded as a significant step toward managing public performance. Although a correlation between the quality of information and its actual usage among managers in high-accountability policy areas has been found, quality performance information has not been properly provided to practitioners. This study takes an Institutional Analysis and Development approach to assess an appropriate institutional framework that facilitates state agencies and academics to coproduce this information. Based on a conceptual framework, we analyze a public information system of the Workforce Data Quality Initiative in Ohio and carry out a content analysis with NVIVO. It is found that arrangements that can manage the incentive dynamic in this process may help to align heterogeneous stakeholders in a mutually supportive fashion. Also, the research agenda and information resulted from being coproduced for management and academic purposes, simultaneously. This use of administrative data sheds light on how quality performance information can be coproduced under an appropriate institutional arrangement between administration and research communities. It is suggested that accessibility to the information system among various stakeholders should be improved.

• Korean Journal of Plant Resources
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• v.23 no.6
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• pp.550-553
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• 2010

The representative research institutes in North Korea are the Academy of Science and the laboratories of major universities. The National Academy of Science consists of headquarters, Academy of Medicinal Science, Academy of Forestry Science, and Academy of Agricultural Science. Under the authority of the National Academy of Science, Central Information Agency for Science and Technology (CIAST) has built up a database system integrating all the science technology data to provide scientific and technological information. The major universities of North Korea include Kim Il-sung University, Kim Chaek University of Technology, Pyongyang Agricultural College, and Wonsan Agricultural College, and an agricultural college is situated in each province. Out of 3,860 plant species in North Korea, 158 species which amounts to approximately 4% of the total are rare and endangered, and deforestation is under a critical situation. The Oriental Medicine (Koryo Medicine) has been well developed using medicinal plants, and practical researches on biotic pesticide are largely conducted as an alternative to tackle the shortage of farming materials. Hereafter, a South-North joint research on the amount of plant resources and the methods of its conservation is needed and the North Korean research areas of biotic pesticide are worth adopting to the South Korean eco-friendly organic agriculture.

• The Journal of Information Systems
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• v.14 no.2
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• pp.101-132
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• 2005

There is a need for research to identify the integrated, rather than fragmented, factors that determine users' acceptance of Internet shopping. Using the newly revised technology acceptance model (TAM) as a theoretical framework, this study investigates the effect of a set of information systems quality (information quality and system quality) and trust on intention to use Internet showing through perceived ease of use and perceived usefulness. Using structural equation modeling, the results strongly support the utilization of TAM in predicting users' intention to use Internet shopping, and demonstrates the effects of critical external variables on behavior intention through perceived ease of use and perceived usefulness. Systems quality such as response time, accessibility, and usability has significant effects on perceived ease of use of Internet shopping. Futhermore, trust has also a significant effect on perceived usefulness, perceived ease of use, intention to use Internet shopping, and actual usage of Internet shopping. Based on these results, this study suggests managerial implications of new Internet shopping strategies, focusing on the integration of information systems quality and trust in order to achieve sustainable competitive advantage in Internet shopping.

• Land and Housing Review
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• v.10 no.1
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• pp.25-32
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• 2019

In this study, the case analysis data on underground temperature are presented. In addition, numerical analysis of the ventilation load reduction plan was derived according to the residence schedule change for the building with cool tube. The research scope and method are as follows. The overall system principle was examined through reviewing the theory of the Cool tube system. Case study and analysis were conducted. Numerical simulation was used to examine the change in energy usage. Also, the change of load energy in case of varying amount of ventilation was derived based on actual building room schedule. When the Cool tube system was applied to the residential buildings, the cooling load was reduced from 3,331 kW to 193 kW, which showed a reduction effect of about 90%.The heating load was reduced from 42,276kW to 32,575kW by 23%.Also, result shows that the cooling load decreased by 24% and the heating load decreased by 66% when the number of ventilation according to the occupancy schedule was applied.

• Journal of the Korean housing association
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• v.24 no.6
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• pp.51-59
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• 2013

The ritual for community is a group ritual performed by the regional community of a village for the safety of the residents and abundant harvests. However, many ritual places have been destroyed by the anti-superstition movement, New Community Movement (Saemaul Movement), industrialization and urbanization since the 1960s. Under the circumstances, this study researched the status of use of the ritual place in Beommul-dong in Daegu where the ritual was revived in 2004 after having been suspended since the end of the 1980s due to urbanization. The revival of the ritual for community in Beommul-dong in Daegu, which had been maintained by the village people alone, is the prime example of the vitalization of local community as the recreation of local community, since the ritual has been transformed into a kind of festival involved with and financed by the local government. The study on analyzing the usage pattern of the ritual place may provide useful sources to come up with the modernized functions of the ritual place as a community place, where the heads of the ward office and cultural center, lawmakers and most of the residents perform the ritual, share foods and tread on the God of the Earth across the village at 11:30 in the morning on every January 16 of the lunar calendar.