• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.1
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• pp.115-123
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• 2012

Material flow control mechanism is a kind of operational policy in manufacturing. It is very important because it varies throughput, throughput time, and work-in-process (WIP) under the same manufacturing resources. Many Researchers have developed various material flow control mechanisms and insisted that their mechanism is superior to others. However the experimental environment used in the performance comparison are different and impractical. In this paper, we set various manufacturing environments to fairly compare five previous material flow control mechanism : Push, Pull, CONWIP, Gated MaxWIP, and Critical WIP Loops. The simulation results show that the Push is superior to others in both of throughput and WIP if required demand is less than 80% of capacity. In addition, the performance of CONWIP and its variants are not different statistically.

• International Commerce and Information Review
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• v.11 no.2
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• pp.303-328
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• 2009

MERCOSUR, which is the biggest economic community in the Latin America, has great potential as Korea's export market with 220 million population and 2.8 trillion$ GDP. In the midst of global economic crises, the importance of MERCOSUR is highlighted with relatively sound economic growth. The average tariff rate of MERCOSUR is 10.4~12.2% which is almost same as that of Korea(12.2%), but the tariff rates on Korea's main export items such as auto, display, digital camera, mobile phone are as high as 20~30%, which means that Korea-MERCOSUR FTA will result in substantial growth of Korea's export. In pursuing Korea-MERCOSUR FTA, cooperations in natural resources, agriculture, mid-sized aircraft, construction and green energy as well as liberalization of commodity market are very important for Korea. To realize Korea-MERCOSUR FTA, it is essential to overcome the objections from the manufacturing sectors of MERCOSUR. So it is desirable to aim relatively low in terms of the level of liberalization at the beginning, and expand corporate and industrial cooperation between Korea and MERCOSUR's manufacturing industries.

• International Commerce and Information Review
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• v.7 no.4
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• pp.435-453
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• 2005

This paper suggests several strategies for promoting Trade and Foreign Direct Investment cooperation to the Korean government and companies as follows ; For Korean government, its trade policy would be given much weight on the import from the Vietnam in the early developing stage. This import could be compensated and increased with the counter export of Korean products like the industrial goods. For Korean companies, they would make haste to invest and develop the abundant energy and natural resources in Vietnam. Their desirable strategies would be moving small scale projects into large ones, production partnerships with the foreign developed and experienced companies, and international joint ventures for using inward FDI incentives. The long range vision and perseverance are indispensable for promoting trade and foreign direct investments between and Korea and Vietnam and both parties' win-win results and development in the end.

• International Commerce and Information Review
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• v.10 no.4
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• pp.321-350
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• 2008

The China has opened the distribution market completely since it joined the World Trade Organization on Dec 11 2001. The notable features of Chinese distribution market are the transition from the consumers' monolithic demand to diversification for the luxury goods, well-being products. The regional characteristics of consumers are smart, conservative, optimistic and advanced. and the open door policy has prompted the capitalistic economy gradually. We analyzed the Chinese distribution markets and came up with the following strategies. First, we recommend the setting of the key regional market not covering the whole chinese markets. then we can extend the main market step by step. Second, we need to cooperate and advance with the Korean distribution companies which entered into markets already. Third, we need to acquire the competitive and stable distribution channel in China. Fourth, we need to implement the localization strategy in terms of human resources and procurement. Fifth, the consignment management can be another strategy. I hope this research can be a little help to those who wish to expand to the Chinese markets.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3171-3191
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• 2016

Due to growing demand on wireless data traffic, a large number of different types of base stations (BSs) have been installed. However, space-time dependent wireless data traffic densities can result in a significant number of idle BSs, which implies the waste of power resources. To deal with this problem, we propose an active state control algorithm based on semi-Markov decision process (SMDP) for a heterogeneous network. A MDP in discrete time domain is formulated from continuous domain with some approximation. Suboptimal on-line learning algorithm with a random policy is proposed to solve the problem. We explicitly include coverage constraint so that active cells can provide the same signal to noise ratio (SNR) coverage with a targeted outage rate. Simulation results verify that the proposed algorithm properly controls the active state depending on traffic densities without increasing the number of handovers excessively while providing average user perceived rate (UPR) in a more power efficient way than a conventional algorithm.

• Journal of the Korea Society for Simulation
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• v.6 no.2
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• pp.71-79
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• 1997

In this paper, operations system was designed for the centralization of data processing of various state information from the facilities of mobile communication network. And the system performance experimental system module was measured and analyzed from the designed experimental system module. The configuration of system design was presented with the centralized type to monite and control the facilities of mobile communication network in the central office. The communication process design of the internal system was implemented with the resource of message queue having a excellent transmission ability for processing of a great quantity of information in the inter-process communication among communication resources of UNIX system. The process with a server function from the internal communication processes was constructed with a single server or a double server according to the quantity of operations and implemented with the policy of the presented server. And then, we have measured performance elements in accordance with the change of input parameters from the designed experimental module : response time, waiting time, buffer length, the maximum quantity existing in message queue. And from these results, we have compared and analyzed the system state each server algorithm according to performance variations.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.84-90
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• 2000

This paper presents a design of an access control mechanism that can resolves the complicated problems of access control requirements in internet environment. In this paper, we proposed an access control mechanism which can satisfy the combined goals of confidentiality integrity and availability of any resource. We defined an access control mechanism from the viewpoints of identity-based, rule-based and role-based policy and implemented 6 access control operations. The Proposed access control mechanism can protect resources from unauthorized accesses based on the multi-level security policies of security label, integrity level, role and ownership.

• Journal of the Korea Society of Computer and Information
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• v.24 no.7
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• pp.143-151
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• 2019

The purpose of the present study was to investigate the causal relationships between social support, spiritual well-being, and depression among family caregivers caring for the elderly in need of long-term care. Based on previous studies and theoretical backgrounds, a mediation research model including the aforementioned variables was proposed. A total of 383 family caregivers from 25 long-term care facilities in G Metropolitan City were included in the present study and hierarchical regression was used. The primary results were as follows. First, family caregivers' social support was negatively associated with depression. Second, family caregivers' social support was positively associated with spiritual well-being. Third, family caregivers' spiritual well-being was negatively associated with depression. Fourth, social support was positively associated with spiritual well-being, which was related to weaker depression among family caregivers. Finally, theoretical implications of these findings and recommendations for policy and practice were also discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.4-7
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• 2022

작업배치스케줄러는 다수의 사용자에게 클러스터 시스템의 계산 자원을 효과적으로 제공하는 유용한 시스템 소프트웨어이다. 한국과학기술정보연구원에서는 작업배치스케줄러인 PBS와 SLURM을 이용하여 슈퍼컴퓨터 5호기 메인시스템인 누리온과 뉴론을 각각 공동활용서비스하고 있다. 본 논문에서는 뉴론의 제한된 계산자원을 다수의 연구자들에게 효율적으로 서비스하기 위해 SLURM 작업배치스케줄러의 공유노드 정책을 적용하는 방안과 작업통계 분석 기법을 소개한다.

• Journal of Information Processing Systems
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• v.20 no.2
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• pp.226-238
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• 2024

Recently, multi-access edge computing (MEC) has emerged as a promising technology to alleviate the computing burden of vehicular terminals and efficiently facilitate vehicular applications. The vehicle can improve the quality of experience of applications by offloading their tasks to MEC servers. However, channel conditions are time-varying due to channel interference among vehicles, and path loss is time-varying due to the mobility of vehicles. The task arrival of vehicles is also stochastic. Therefore, it is difficult to determine an optimal offloading with resource allocation decision in the dynamic MEC system because offloading is affected by wireless data transmission. In this paper, we study computation offloading with resource allocation in the dynamic MEC system. The objective is to minimize power consumption and maximize throughput while meeting the delay constraints of tasks. Therefore, it allocates resources for local execution and transmission power for offloading. We define the problem as a Markov decision process, and propose an offloading method using deep reinforcement learning named deep deterministic policy gradient. Simulation shows that, compared with existing methods, the proposed method outperforms in terms of throughput and satisfaction of delay constraints.