• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.390-399
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• 2011

Generally the life-cycle cost of complex systems composed of several sub systems or equipments such as train, aircraft weapon systems is spent much more during operation and maintenance phase than development phase. The maintenance cost for maintaining the availability and extending the life span of systems comprise a large proportion of systems operation cost. The cycle of preventive maintenance affects operation and maintenance cost a lot. In this study we introduce a way minimizing life-cycle cost of systems by calculating more reliable preventive maintenance period than the results of previous study using systems reliability data considered the reliability and failure effect ratio of sub-systems or components. We can solve the preventive maintenance period problem known as NP-Hard as quick as possible by using modified genetic algorithm than using other models introduced in previous study.

• Journal of Korean Institute of Industrial Engineers
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• v.40 no.1
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• pp.118-127
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• 2014

The configuration such as series, parallel and k-out-of-n of a repairable system directly affects its reliability. The maintenance strategy can also affect the overall performance of the system. The objective of this work is to investigate the possible trade-off between the configuration of a repairable k-out-of-n system and its maintenance strategy. The redundancy is considered to be the design decision variables, whereas the preventive maintenance period is considered to be the maintenance decision variables. The optimization model is used to minimize the overall life cycle cost associated with the system, considering constraint on reliability. Finally, genetic algorithm is used to find the optimal values for the decision variables. The result is compared with optimal values for considering redundancy and maintenance respectively.

• IE interfaces
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• v.14 no.1
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• pp.30-38
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• 2001

Logistics network management has become one of the most important sources of competitive advantage regarding logistics cost and customer service in numerous business segments. Logistics network simulation is a powerful analysis method for designing and planning the logistics network optimally in an integrated way. This paper introduces a logistics network simulator, LONSIM, developed by author. LONSIM deploys a mix of simulation and optimization functions to model and analysis logistics network issues such as facility location, inventory policy, manufacturing policy, transportation mode, warehouse assignment, supplier assignment, order processing priority rule, and vehicle routes. LONSIM is built with AweSim 2.1 and Visual Basic 6.0, and executed in windows environment.

• Journal of Korea Port Economic Association
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• v.18 no.1
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• pp.107-134
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• 2002

Globalization of the industry induces the internationalization of any given manufacturing company's supply chain. Development of e-Commerce and Information Technology (IT) changes the logistics structure, making logistics information systems essential. Web-based connectivity and supply chains based on new technologies are becoming essential in the logistics industry. Customers are driving the implementation of systems to ensure timely, thorough, and accurate information, often with immediate access; in response, the Internet has propagated tracking and tracing systems. Value-added services are the key to successful intermediary activities. The nationwide Integrated Logistics Information System (ILIS) aimed to utilize existing and future information infrastructure and knowledge bases to build an integrated logistics information network that would provide comprehensive logistics information services for shippers and carriers in order to improve the efficiency of both inventory and information flows in their supply chains. The ILIS, as one of the seven national information networks, has provided various services, particularly services related to import/export and clearance. Though a survey concerning logistics information services shows rather positive results, shippers and carriers still require better services and reductions in EDI prices. Therefore, the role of the ILIS needs to be re-defined. Short-term plans for the ILIS contain ICD services and XML/EDI services, which are described in detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.149-158
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• 2019

The scheduling of planned maintenance problem of a system consisting of a number of components was studied. The purpose of maintenance scheduling is to minimize the cost of maintaining long-term operations. On the system side, the cost of a system shutdown can be minimized by grouping and inspecting a number of components. In addition, proper inspection cycles can be selected for each component to identify the failure sufficiently early to minimize the cost of the failure. To reduce the complexity of the calculations, the 'base interval approach' used in previous studies was applied and, in addition, the inspection cost savings from simultaneous inspections of multiple components were considered. To compare the effectiveness of inspection cost savings, this paper presents the results of simulation analysis performed by referring to the cases in the existing studies.

• Korea Logistics Conference
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• v.14 no.1
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• pp.1-11
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• 2006

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.13-15
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• 2013

The purpose of this research is to provide the logistics research with a focus on the methods and theory of the research. This paper finds to explain the patterns of logistics research in domestic through the investigation of different theories and research methods employed. A analysis of methods in selected topics allows published research of the logistics to be categorized. Research classified into integrated table by each theory, research topic, methodology and triangulation. Study presented a variety of research paradigms in logistics and contributed to the current literature by providing an outlook of the logistics research.

• Journal of Korea Port Economic Association
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• v.24 no.1
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• pp.23-39
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• 2008

This paper outlines a plan to promote South Jeonnam region's logistics capability in connection with the regional logistics bases such as Gwangyang Port, Jangseong Integrated Freight Terminal, Mokpo Port and Muan International Airport. The capability of regional innovation bodies, and industrial innovation generally, needs to be improved by establishing a systematic regional innovation plan. Smaller import and export logistics bases, presently scattered in downtown Gwangju and its suburban area, need to be integrated as soon as possible, in advance of the completion of a traffic network connecting all of the triangle logistics bases. Moreover, plans to develop Muan International Airport to the status of a hub airport need to be established, and its function as an air freight terminal should be strengthened. Gwangyang Port and Mokpo Port should be developed as Korea's key harbors with international logistics bases the two ports, presently conducting simple cargo work, should be transformed into general logistics ports conducting logistics, assembling, trading, and international business by developing their surrounding areas.

• Journal of Navigation and Port Research
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• v.43 no.4
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• pp.256-263
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• 2019

The trade volume of Northeast Asian countries is increasing and with the advent of the 4th revolutionary era, minimizing the logistics costs of firm is becoming an important competitive factor. With respect to this, in 2006, the government introduced a certified Integrated logistics firm system to improve the competitiveness of local logistics firms and reduce the logistics costs of firms. They argued that the certified Integrated logistics firm system increased the reliability of logistics firms and increased the efficiency of the logistics industry. On the other side, they argue that the system puts a burden on firms and becomes a big business-oriented market consolidation. This study analyzed the efficiency of Warehousing firms using DEA model. The CCR, BBC efficiency and RTS (return to scale) of 15 Warehousing firms were evaluated. This study also suggested the Warehousing firms which can be benchmarked based on analyzed information.

• Journal of Power Electronics
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• v.19 no.2
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• pp.602-611
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• 2019

The major drawbacks of magnetic resonant coupled wireless power transfer (WPT) to the embedded sensors on spindles are transmission instability and low efficiency of the transmission. This paper proposes a novel double-loop coil design for wirelessly charging embedded sensors. Theoretical and finite-element analyses show that the proposed coil has good transmission performance. In addition, the power transmission capability of the double-loop coil can be improved by reducing the radius difference and width difference of the transmitter and receiver. It has been demonstrated by analysis and practical experiments that a magnetic resonant coupled WPT system using the double-loop coil can provide a stable and efficient power transmission to embedded sensors.