• IE interfaces
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• v.17 no.spc
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• pp.141-151
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• 2004

As today's business environment has become more and more competitive, forward as well as backward flows of products among members belonging to a supply chain have been increased. The backward flows of products, which are common in most industries, result from increasing amount of products that are returned, recalled, or need to be repaired. Effective management for the backward flows of products has become an important issue for businesses because of opportunities for simultaneously enhancing profitability and customer satisfaction from returned products. Since third party logistics service providers (3PLs) are playing an important role in reverse logistics operations, they should perform two simultaneous logistics operations for a number of different clients who want to improve their logistics operations for both forward and reverse flows. In this case, distribution networks have been independently designed with respect to either forward or backward flows so far. This paper proposes a mixed integer programming model for the design of network integrating both forward and reverse logistics. Since the network design problem belongs to a class of NP-hard problems, we present an efficient heuristic algorithm based on genetic algorithm (GA), of which the performance is compared to the lower bound by Lagrangian relaxation. Finally, the validity of proposed algorithm is tested using numerical examples.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.895-899
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• 2009

This paper presents a business models of the robot industry for copying with aging society that facilitates to create new business opportunities in the convergence age. In order to identify the market drivers for both convergence and aging society, the trends of them analyzed. Through constructing and analyzing market value chain, we design a set of the business model of the robot industry focused on u-health robots of a convergence service type integrated ubiquitous, health and robot. In addition, we describe the evolution path of the proposed business model in terms of technology development and market. Finally, we develop a matrix based evaluation framework to measure and assess the effectiveness of the business model.

• Journal of Information Technology Services
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• v.8 no.4
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• pp.75-86
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• 2009

Unlike physical products, the distribution of digital content has involved many participants in all distribution phases from providers to consumers. The longer the distribution channel for services is, or the more participants that take part in it, the more the added value of the content increases. Consequently, the customer usefulness has been maximized. In order to enhance the values of digital content, it is utterly urgent to implement a service infrastructure that could be shared by all participants along the distribution path. Digital content is distributed from a creator to a final user through complex value chain stages. All the participants along the value chain exchange information about copyrights, marketing, and contents themselves, through the distribution channel. Recently, the more the distributed Information Technology environment has been widely used, the more the necessity of an identifier for digital content has been increased. In this paper, we examine the current status of the Korean distribution market of digital content, identify necessary distribution services of digital content, and establish a systematic roadmap to implement these services.

• Journal of Distribution Science
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• v.18 no.3
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• pp.37-41
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• 2020

Purpose: The purpose of this paper is to examine the recent resurgence of popularism and the possible impacts it may have on contemporary business and economics. Research design, data and methodology: This is an exploratory case study that examines the rise of popularism and identifies and analyzes the likely implications for contemporary business and economics. Results: Although populists tend to reject elitism, capitalism, economic globalization, and political establishment, their ethnocentric behavior is no different from those of the corrupt political and economic elites. Popularism does enable nationalism and protectionism and negatively impacts business and economic growth. Conclusions: Popularism existed for a long time, and this phenomenon will continue to exist as long as a triggered mechanism exist, e.g., income inequality, resurgence of immigration, recession, insufficient factors of resources and social welfare. The recent rise of popularism is not a fad or a short-lived anti-establishment and anti-elitism movements but, rather, a force to be reckoned with in the near future. The rise of economic nationalism limits international trade, integration, and cooperation. As a result, international capital, service, and product flows will decline, and countries and multinational corporations have to develop and restructure their international supply and value chain to cope with this phenomenon.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.58
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• pp.59-69
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• 2000

Development of digital information and internet technology causes the changes of technology environments and companies, and the variety of customer needs has been dynamically changed in terms of integrating information system with customer satisfaction. Moreover a new logistics concept is needed through the sharing information between suppliers and consumers, which maximizes the level of customers service and its flexibility by changing functional-oriented to process-oriented. In other words, Supply Chain Management (SCM) is now considered as a key aspect of business, which controls the flows of information, funds, and goods in the supply chain. Rationalization of transport-delivery system will be one of the most important issues on logistics management to the domestic companies. The companies need the effective delivery system. Especially in the case of delivery system from distribution centers to customers or vendors, it might take a long time to control the delivery system manually because it would be hard to apply the automatic vehicle routing algorithm effectively considering all the practical constraints. Thus this study develops a heuristic algorithm of automatic vehicle delivery support system in terms of grouping by short ranges of vehicle movement utilizing postal coordinates, which satisfies a variety of realistic constraints and reduces controlling time of manual operations. In addition, the performance of the algorithm developed in this study is evaluated through the case study.

• Management Science and Financial Engineering
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• v.15 no.1
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• pp.1-31
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• 2009

This paper considers the value of warehousing contract under probabilistic demands. We consider a supply chain consisting of a supplier, a retailer and its third-party warehousing partner who provides the warehousing service to the retailer through an outsourcing contract. A typical contract is specified by initial space commitment and modification schedule. The retailer decides the order quantity for the supplier and space commitment for the outsourcing contract. Since there is close relationship between order quantity and space commitment to minimize the total cost including ordering cost, inventory carrying cost, shortage cost, and warehousing cost, we develop an analytical model under probabilistic demands, where the retailer can determine the optimal order size and space commitment level jointly. We found the closed-form optimum for a single-period case and the optimal conditions for a two-period case. To evaluate the value of contract flexibility for the two-period case, we compared the total cost under two policies; one with modification, under which the base commitment can be changed at the start of each period and the other without modification. From results of our numerical analysis, we showed that the modification policy is more cost-effective as the variability of demand increases.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.61-77
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• 2017

The most challenging issues in the multi-channel MAC of the IEEE 1609.4 standard is how to handle the dynamic vehicular traffic condition with a high mobility, dynamic topology, and a trajectory change. Therefore, dynamic channel coordination schemes between CCH and SCH are required to provide the proper bandwidth for CCH/SCH intervals and to improve the quality of service (QoS). In this paper, we use a Markov model to optimize the interval based on the dynamic vehicular traffic condition with high mobility nodes in the multi-channel MAC of the IEEE 1609.4 standard. We evaluate the performance of the three-dimensional Markov chain based on the Poisson distribution for the node distribution and velocity. We also evaluate the additive white Gaussian noise (AWGN) effect for the multi-channel MAC coordination scheme of the IEEE 1609.4 standard. The result of simulation proves that the performance of the dynamic channel coordination scheme is affected by the high node mobility and the AWGN. In this research, we evaluate the model analytically for the average delay on CCHs and SCHs and also the saturated throughput on SCHs.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.363-370
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• 2006

Porcine reproductive and respiratory syndrome (PRRS) is an economically important disease of swine that occurs all over the swine industry worldwide. It was first observed in the Unite States in 1987 then in Europe in 1990. It has been described in Japan and in Korea in 1993. PRRS virus is divided into two distinct types, North American and European, genetically. Based on our limited knowledge there has been no report on the existence of European PRRSV. But according to the government's Korea Customs Service there has been many importations of breeding pigs from Europe. These seem to make an estimate that European PRRSV could be introduced in Korea by inflow of European breeding pigs. We first detected the European PRRSV could be introduced in Korean pig farms by using polymerase chain reaction (PCR). Further, it is also identified that there are not only North American PRRSV antibody but also a European PRRSV antibody. According to the genetical and serological experiment results, the presence of established North American PRRSV in Korea is due to the use of live vaccines made of North American PRRSV strain as well field virus infection, and the European PRRSV is possibly introduced from imported breeding stock.

• Journal of the Korean Society of Food Culture
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• v.4 no.3
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• pp.229-236
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• 1989

Fast food restaurants are growing in numbers in Korea since they were introduced abot a decade ago. To develop an effective marketing strategy for fast foods, it is important to assess consumer's acceptability and identify demorgraphic, environmental, and managerial factors which influence consumer's perception on the fast food restaurants. A total of 595 customers were surveyed at thirty hamburger chain restaurants in Seoul from November 7 to 15, 1988. Analyses of the collected data revealed that adolescents, females, and the people with high income were the major customers and visited more than once or twice a week; frequent visitors rated meals more favorably in terms of the quality, service and cleanliness, and they also rated meals of foreign brand more favorable than those of domestic one; the female group perceived the change in their dietary habits more than any other groups; cleanliness, convenience, atmosphere, courtesy, and the taste of foods were significant factors in purchasing fast foods; and customers were most satisfied with convenience, while least satisfied with the price and the quantity of foods. From these findings, it is sggested that the manager of the fast food restaurant must consider the consumer's perception of fast foods in terms of pros and cons in order to operate her/his restaurant successfully.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2499-2522
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• 2017

Multi-hop networks are a low-setup-cost solution for enlarging an area of network coverage through multi-hop routing. Carrier sense multiple access with collision avoidance (CSMA/CA) is frequently used in multi-hop networks. Multi-hop networks face multiple problems, such as a rise in contention for the medium, and packet loss under heavy-load, saturated conditions, which consumes more bandwidth due to re-transmissions. The number of re-transmissions carried out in a multi-hop network plays a major role in the achievable quality of service (QoS). This paper presents a statistical, analytical model for the end-to-end delay of contention-based medium access control (MAC) strategies. These strategies schedule a packet before performing the back-off contention for both differentiated heterogeneous data and homogeneous data under saturation conditions. The analytical model is an application of Markov chain theory and queuing theory. The M/M/1 model is used to derive access queue waiting times, and an absorbing Markov chain is used to determine the expected number of re-transmissions in a multi-hop scenario. This is then used to calculate the expected end-to-end delay. The prediction by the proposed model is compared to the simulation results, and shows close correlation for the different test cases with different arrival rates.