• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.120-128
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• 2015

In this paper, Residential roof top photovoltaic system with 9.9 kW design is proposed. The system composed of 200 Watts solar array 33 panels connecting in series 10 strings and parallels 3 strings which have maximum voltage and current are 350 V and 23.8 A. The 10 kW sinusoidal grid-connected inverter with window voltage about 270-350 is selected to convert and transfer DC Power to AC Power at PCC (Point of Common Coupling) of power system following to utility standard. However the impact of fluctuation and uncertainty of weather condition of PV may decrease the voltage stability and voltage collapse of power system. In order to solve this problem the energy storage such 120 V 1200 Ah battery bank and 30 kVAR capacitor are designed for voltage stability control. The other expensed for installing the system such battery charger, cable, accessories and maintenance cost are concerned. The economic analysis by using investment from money loan with interest about 7% and use own money which loss income of deposit about 3% are calculated as 671,844 and 547,044 for PV system with energy storage and non energy storage respectively. The solar energy from PV is about 101,616 Bath per year which evaluated by using the value of $5kWh/m^2/day$ from average peak sun hour (PSH) of the Thailand and 6.96 Bath/kWh of Feed in Tariff Incentive. The payback periods of four scenarios are proposed follow as i) PV system with energy storage and use loan money is 15 years ii) PV system with no energy storage and use loan money is 10 years iii) PV system with energy storage and use deposit money is 9 years iv) PV system with energy storage and use deposit money is 7 years. In addition, the other scenarios of economic analysis such no FIT support and other type of economic analysis such NPV and IRR are proposed in this paper.

• Journal of Digital Convergence
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• 제18권12호
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• pp.47-57
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• 2020

This paper aims to show the development pattern of the impact of artificial intelligence on the arts and culture according to the scenario analysis, and suggests the direction of the arts and culture content industry in the future. We assume four scenarios based on creativity of artificial intelligence beyond humans and controllability for them, then explore the path leading to each scenario. In addition, for the most ideal route to coexist with artificial intelligence, we propose the provision of safety system for human and artificial intelligence, innovation of the education system, and preemptive investment from now on.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제39권3호
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• pp.30-38
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• 2016

Shuttle-Based Storage/Retrieval System (SBS/RS) is relatively new to industry. The system is in the category of Automated Storage/Retrieval System (AS/RS), but it is different in that the SBS/RS uses shuttles as Storage/Retrieval (SR) machine instead using a stacker crane. The shuttles are assigned to each tier on multi-tier system and operated for pick-up or drop-off order. Since the system can handle multiple orders simultaneously, it can provide much higher throughput than that of general AS/RS with single stocker crane. Thus, this new system is well fit to recent tendency of increasing small quantity batch production and orders. One of the drawback of this system is that it needs a lot of investment to set up. The efficient operation of the system would be one of the critical matters to increase economic efficiency of capital investment. In this study, we focused on the dwell point policy for shuttles to find efficient way of operating the system. There are four basic policies for the dwell point and we had simulation-based experiment for two different scenarios based on the speed of the shuttle and inter-arrival time of the loads coming to the system combined with four different policies. As it was mentioned above, this SBS/RS relatively new to the field and there is no such experiment shown on previous research and the study of dwell point policy for this SBS/RS could provide the direct comparison of each policy with different hardware specification; the capability of the system. The policy that achieves most efficient operation among the given environment is proposed and the usability of the system is discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제31권7B호
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• pp.660-667
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• 2006

Voice over Wireless LAN (VoWLAN) is defined as a communication service which transmits voice over wireless LAN. Due to its capability of providing high quality service while reducing communication costs, the VoWLAN is expected to be widely introduced to hospitals, hotels, and many more industry sectors. However, despite the increased interest in the new service, there has been limited research on the economic assessment of deploying VoWLAN. This paper provides a systematic and quantitative approach to the return on investment (ROI) analysis of VoWLAN service. We first analyze the domestic and international market trend of VoWLAN. Then, implementing scenarios of VoWLAN and corresponding alternatives are established. For each scenario, cost and benefit analysis is conducted. The proposed framework is implemented by using VBA program. To validate the result of the analysis, a case study is also conducted.

• Journal of the Korean Society for Railway
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• 제12권3호
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• pp.427-436
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• 2009

This paper introduced Railway Network Design Problem (RNDP) to provide priority decisions on high-speed railway investment scenarios defined by various network segments and train systems. The RNDP optimizes the objective functions of minimize total travel time. Results show that the priority of high-speed railway investment is found to be East-west, West-coast, and South-coast line respectively. An entirely new line built with 400km/h is found to be the best alternative to East-west line. Regarding West-coast and South-coast line, the combined alternative of upgrading Geolla and Kyeonjon line with 200km/h and building a new line with 400km/h and 350km/h for remains of each line is the best.

• Journal of Information Science Theory and Practice
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• 제7권1호
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• pp.39-51
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• 2019

Open access is a paradigm whereby the electronic versions of scholarly publications are made freely accessible without any restrictions. It is actively promoted globally and is also promoted domestically in accordance with this global trend. However, there is a growing need to evaluate existing activities and to seek policies for the steady spread of open access. This study examines the necessity of switching to a national repository from existing institutional repositories through policy direction analysis of open repositories. We examined domestic open access policies by analysing various overseas cases and the situation in South Korea. Finally, we determined the validity of investment in a national repository by analysing its social and economic impacts using the modified Solow-Swan model. The main parameters for applying the modified Solow-Swan model were estimated, and the domestic research and development expenditure was predicted via a regression method. Then, we applied a range of rate of returns to research and development (10% to 50%) to various scenarios and examined the effects of increasing accessibility and efficiency by 1% to 10%. We found that the implementation of a national open access repository in South Korea would have a substantial impact (to the tune of 147 billion won), without considering the potential costs of such a repository. Based on the estimates of the social and economic impact of a national repository, the implementation of a national open access repository in South Korea is economically viable. Besides having beneficial social and economic impacts, a national repository is expected to enhance awareness of open access among Korean researchers and institutions.

• Korean System Dynamics Review
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• 제8권2호
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• pp.141-173
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• 2007

In Korean context, the innovative cities imply new towns or urban clusters in the Non Capital Regions, all of which would accommodate the relocated Capital based public organizations. The central government-initiated innovative cities have provoked pros and cons towards their effectiveness and efficacy for the balanced territorial development. From a broader prospective, this paper firstly examines the current status quo of the innovative cities. Based on their master plans, it analyzes physical and non physical factors which would exert significant impact on the innovative cities. Secondly, it pays attention to how key factors strengthen or weaken their behavioral patterns in terms of dynamic location and implementation policies of the innovative cities. Using System dynamics approaches, it sets up couples of scenarios, categorizing between supporting and opposing arguments towards the innovative cities. Lastly, after divulging systematic structure of the innovative cities, it proposes a series of practical alternatives which would contribute to minimizing unexpected side effects or unwanted social cost in the long run. In order to guarantee reinforcing structure of the innovative cities, the paper suggests that QOL (quality of life) variables, which would require continuous investment in the social infrastructure, are pivotal in achieving original goals of the innovative cities. Otherwise, the innovative cities would not be innovative per se. In the worst case, they might be degraded into the unpopular ghost towns.

• Journal of the Korean Society of Safety
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• 제35권3호
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• pp.72-78
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• 2020

The accident fatality rate has decreased by more than 90% compared to 2006, due to the safety management and safety investment based on the Rail Safety Act. Most railway safety indicators, including fatality rates, have improved significantly from 60% to 80%, reaching the level of developed countries in terms of most railway safety indicators. However, the only staff fatality rate at work is not improved, and it is 3 to 5 times higher than that of developed countries. Most of the fatality occurred during employee's work recently occurred due to accidents hit by train while track work. In principle, when operating track need to check or maintenance, the operation of the train should be stopped and the work carried out. However, in Korea, due to the highest passenger density and train operating density in the world, it is caused by a structural problem that requires workers to enter the track while the train is running and perform various tasks such as maintenance and inspection. In this study, we analyzed the risk of accidents caused by hit by trains on the track, which is the biggest cause of staff fatality, using the main statistics of the last 10 years. In detail, the scenarios of the main causes of hit by trains and workers were formed to suggest the effectiveness of the current preventive measures and supplementary.

• Proceedings of the Technology Innovation Conference
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• 기술경영경제학회 1997년도 제11회 하계학술발표회 논문집
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• pp.286-306
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• 1997

This paper analyses the B-ISDN evolution strategy based on economic perspective, in terms of its effect on national competitiveness and quality of life. In the beginning, it considers the economic characteristic related with the emergences of B-ISDN services. The economic goods resulting from their services is classified by producer and consumer goods. The time difference between R&D and investment is also included to identify the technology gap between countries. And then, this paper intensifies the economic approach by complementing the technical factors which include both the network evolutionary characteristic and cost-effective implementation. The feasible scenarios are thereby obtained, one for technologically advanced countries and two for technologically unadvanced countries. The result of this study shows that technologically advanced countries can not only intensify their national competitiveness but also enhance quality of life, but not in the case of technologically less advanced countries.

• Korean System Dynamics Review
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• 제3권1호
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• pp.43-60
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• 2002

This paper describes the forecast of wholesale price in competitive Korean electricity market using the system dynamics approach. The system dynamics concepts have been implemented with the Ithink software. This software facilitates the development of stock and flow model with information feedback. Using this model, the future wholesale electricity price can be computed hour by hour, quarterly, and yearly. This model also gives the energy planner the opportunity to create different scenarios for the future of deregulated wholesale markets in Korea. Also It will lead to increased understanding of competitive wholesale market as a complex, dynamic system. Research results show that the plant construction appeared in waves of boom and bust in Korean electricity market like real estate construction. That is, the Korea wholesale market's new power plants and the market price will appear the Boom and Bust cycle. It is very similar behavior as real estate industry. In case of consideration of DSM program, The DSM savings lead to a somewhat different timing of the booms in construction and of price spikes. But the DSM programs do not eliminated the fundamental dynamics of the boom and bust. And the wholesale price is maintained at the lower level compared to the case of without DSM program. However, the unexpected result is found that due to the lower market price, Investor make significantly less investment in new CCs, which leads to the higher wholesale price after 2010. It suggests that the DSM Policy must be implemented with the dynamics of competitive Electricity Market.