• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.31-40
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• 2003

This paper studies an optimal policy for a certain class of (s, S) inventory control systems, where the demands are characterized by the renewal arrival process. To minimize the average cost over a simulation period, we apply a stochastic optimization algorithm which uses the gradients of parameters, s and S. We obtain the gradients of objective function with respect to ordering amount S and reorder point s via a combined perturbation method. This method uses the infinitesimal perturbation analysis and the smoothed perturbation analysis alternatively according to occurrences of ordering event changes. The optimal estimates of s and S from our simulation results are quite accurate. We consider that this may be due to the estimated gradients of little noise from the regenerative system simulation, and their effect on search procedure when we apply the stochastic optimization algorithm. The directions for future study stemming from this research pertain to extension to the more general inventory system with regard to demand distribution, backlogging policy, lead time, and inter-arrival times of demands. Another direction involves the efficiency of stochastic optimization algorithm related to searching procedure for an improving point of (s, S).

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.431-439
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• 2001

This Paper illustrates a new numerical analysis method using a nodal effective load model for nodal probabilistic production cost simulation of the load point in a composite power system. The new effective load model includes capacities and uncertainties of generators as well as transmission lines. The CMELDC(composite power system effective load duration curve) based on the new effective load model at HLll(Hierarchical Level H) has been developed also. The CMELDC can be obtained from convolution integral processing of the outage capacity probabilistic distribution function of the fictitious generator and the original load duration curve given at the load point. It is expected that the new model for the CMELDC proposed in this study will provide some solutions to many problems based on nodal and decentralized operation and control of an electric power systems under competition environment in future. The CMELDC based on the new model at HLll will extend the application areas of nodal probabilistic production cost simulation, outage cost assessment and reliability evaluation etc. at load points. The characteristics and effectiveness of this new model are illustrated by a case study of MRBTS(Modified Roy Billinton Test System).

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.3
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• pp.373-389
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• 2009

The aims of this study are to examine urgent problems for reorganization into future-proof large purse seine fisheries in order to positively cope with rapidly changing domestic and foreign fisheries circumstances. First, this paper provides current situations of the large purse seine fisheries. The current situations of it are composed of fisheries influence such as vessel number, vessel power, and fisher number, use of resource and fishing places, and changes in products and sales of species caught by the large purse seine. Secondly, this paper reviews current problems of the large purse seine fisheries including cost reduction and increase of value added. Thirdly, this paper suggests basic development direction and countermeasures for strengthening competitiveness of the large purse seine fisheries. In conclusion, urgent problems of the larger purse seine fisheries can be summarized as inefficiency of distribution structures and retarded landing system and facilities as well as the worse of profitability according to shrink of fishing places, reduction of products, lack of workers, and increase in oil price. To solve the urgent problems, the large purse seine fisheries should be changed into an industry with low cost and high efficiency, and also need to introduce of new production system, strengthen autonomous management of natural resource, and increase in value added to products.

• KIEAE Journal
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• v.9 no.1
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• pp.3-10
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• 2009

There are more interests and studies to change the buildings into eco-friendly spaces as the present age recognizes nature-friendly environment more and more. In response to this trend, the government reinforces regulations for the variety of the eco-friendly buildings using a certification system. The eco-friendly certification system which was started only for residing since 2002, and this has been now for schools that are the spaces of the students who will lead the future since March 2005. The purpose of this study is to help understanding of the eco-friendly buildings, and to popularize and activate those as developing and making up for the classification system, evaluation items, detailed standards to evaluate them more precisely by analysing eco-friendly planning features and data of the eco-friendly certificated schools. This study selected 15 eco-friendly certified schools among the schools certified by the Ministry of Land, Transport, and Maritime Affaires since 2005, and analyzed evaluation result. After the analysis, I had a thorough grasp of the point distribution of the each building, analyzed the cause of the low points or no points, and tried to find the improvements. There should be continuing adjustment and complement for the evaluation items and detailed standards, and these should be applied to models as well as certified schools. Active public relations are also needed to educate the public and elevate their participation.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.936-939
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• 2003

Potential and capabilities of GIS in planning and decision-making is widely known as an experimental tool, but its existence in real-world application is yet to realize. GIS originated in the field of cartography and even at today it is mainly used as a tool for map production. Number of reasons could bring forward for this shortcoming. Limited real-world applications could be a significant one among them. This paper describe an attempt to use GIS technology in Lao PDR where a study team was involved in formulating a Master Plan for national healthcare system. A database was created for the whole country with spatial and descriptive data gathered from various sources. Attempt was made to demonstrate the potential of GIS by using the database for identifying healthcare status, distribution of resources, recognizing deprived areas and locating areas for future investments based on accessibility and social status. The approach justified the investment on a GIS system and introducing the system in the planning sector from grass-root level to central level.

• The Journal of Fisheries Business Administration
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• v.51 no.4
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• pp.137-146
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• 2020

In this study, the differences of institutional development processes of fishery products wholesale markets were compared between Korea and Japan in order to suggest improvement direction of trading system in Korea. The wholesale markets have shrunk while wholesale and distribution has been becoming larger in size in both countries. A summary of differences in the wholesale market trading systems between Korea and Japan is as follows: first, middle wholesalers play pivotal roles in wholesale transaction in Korea, and wholesale corporations take such roles in Japan. Second, most wholesale corporations take charge of listing in Korea whereas such corporations are in charge of buying in Japan. Third, Korea has high proportion of auction for transactions, in contrast to Japan with high proportion of relative transactions. Forth, Korea maintains more sales within the wholesale markers and has more small and medium customers than Japan. Finally, Korea investigates inside causes to find solutions for the decreased competitive power of the wholesale market, whereas Japan copes with the problem by searching for outside customers. To seek solutions for the decreased competitiveness of Korean fishery products wholesale markets, middle wholesalers' consignment should be limitedly allowed, and improvement direction of wholesale corporations should be investigated in the future study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5898-5916
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• 2018

In this paper, the downlink performance of multi-cell distributed antenna systems (DAS) with a single user in each cell is investigated. Assuming the channel state information is available at the transmitter, four transmission modes are formulated as combinations of remote antenna units (RAUs) selection and cooperative transmission, namely, non-cooperative transmission without RAU selection (NCT), cooperative transmission without RAU selection (CT), non-cooperative transmission with RAU selection (NCT_RAUS), and cooperative transmission with RAU selection (CT_RAUS). By using probability theory, the cumulative distribution function (CDF) of a user's signal to interference plus noise ratio (SINR) and the system ergodic capacity under the above four modes are determined, and their closed-form expressions are obtained. Furthermore, the system energy efficiency (EE) is studied by introducing a realistic power consumption model of DAS. An expression for determining EE is formulated, and the closed-form tradeoff relationship between spectral efficiency (SE) and EE is derived as well. Simulation results demonstrate their consistency with the theoretical analysis and reveal the factors constraining system EE, which provide a scientific basis for future design and optimization of DAS.

• Journal of Information Technology Services
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• v.22 no.1
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• pp.29-42
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• 2023

Amid the global movement to harness individual data and boost the data economy, MyData services that utilize personal data are being implemented in earnest in the financial sector in Korea due to the government's active encouragement policy. To this end, MyData service providers must have a service system for business operators that collects and efficiently loads personal information scattered in various financial institutions with individual consent, and comprehensively analyzes and provides it. The system must not only have strict security management capabilities, but also be built in a flexible form that takes into account future data scalability and additional services. In this paper, it has been proposed to be implemented the essential functions that MyData service system must have and the core functions that can manage the entire data life cycle from data collection, distribution to disposal in the form of a platform. In addition, the strengths of the platform structure were reviewed, and the effectiveness of the platform model was examined upon application.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.5
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• pp.487-496
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• 2022

This study attempts to discover a differentiated service strategy for the hotpot restaurant industry from the perspective of Chinese Generation Z customers, as well as to further explore the inner needs of Chinese Generation Z to make practical implications for discovering the method of gaining their satisfaction and loyalty. This paper employs questionnaires to collect analytical data and through a case study to produce company strategies. Smith's Marketing Ethics Sequential System Model (SMESSM) is introduced in this paper for the decision of whether the case study company Haidilao Hot Pot should make a new strategy on service based on Generation Z's consuming behavior. The findings of this study demonstrate that hotpot restaurant must differentiate their services for Generation Z from older generation customers to gain a sustainable development of the hotpot business. Proper differentiated service will not only improve Generation Z's dining experience but also reduce costs. This paper is the first to discuss differentiated service strategy in the hotpot restaurant business from the perspective of Generation Z customers. And a Chinese experience of SMESSM for practical use is introduced in this paper, which enriches the relevant implications for future research on business strategy.

• Asia Marketing Journal
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• v.7 no.3
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• pp.105-119
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• 2005

Samsung Fire & Marine Insurance Co., Ltd. launched 'Samsung Super Insurance Package', an insurance policy combining household's property & casualty insurance policies, except insurance with savings and pension insurance, into one for the first time in Korea. The product was developed to tackle challenges and threats from environmental changes, whose success owes to an excellent marketing strategies like adopting MCS system which is coined to support sales force activities, and building SRC(Samsung Risk Consultant), the organization dedicated to the sales of the product. The case shows how Samsung Fire & Marine Insurance Co., Ltd. developed and successfully marketed the combined insurance policy for the first time in Korea identifying the key success factors and discusses its business implications and future challenges.