• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.191-194
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• 2003

In IEEE 802.11b, Medium Access Control Sublayer consists of DCF (Distributed Coordination Function) and PCF (Point Coordination Function). DCF provides contention based services and PCF provides contention free services for QoS satisfaction. DCF uses CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) as an access protocol. And PCF uses Polling Scheme. In this paper, a modified New-PCF, which gives weights to channels with heavier traffic load, was suggested. NS-2 simulations were conducted to compare the service performances with original DCF, PCF and the modified New-PCF respectively. Simulation results has shown the increased overall throughput with the proposed New-PCF compared with other cases.

• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.14-19
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• 2015

In multicellular wireless networks, intercell interference limits system performance, especially cell edge user performance. One promising approach to solve this problem is the intercell interference coordination (ICIC) scheme. In this paper, we propose a new ICIC scheme based on a resource partitioning approach to enhance cell edge user performance in a wireless multicellular system. The most important feature of the proposed scheme is that the algorithm is performed at each base station in a distributed manner and therefore minimizes the required information exchange between neighboring base stations. The proposed scheme has benefits in a practical environment where the traffic load distribution is not uniform among base stations and the backhaul capacity between the base stations is limited.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.8
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• pp.477-483
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• 2004

In competitive electricity markets, maintenance schedule is submitted by generation companies (GENCOs) and transmission companies (TRANSCOs), and coordinated by Independent System Operator (ISO) with the adequacy criterion. This paper presents an alternative coordination procedure by ISO on the maintenance schedule. In this paper, it is focused on modeling a coordination algorithm by ISO for the maintenance schedule based on the Simulated Annealing algorithm. The proposed model employs the minimum information such as generator capacity, forced outage rate and generator maintenance schedules. The objective function of this model represents minimization of adjustment on schedules submitted by GENCOs.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.249-256
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• 2003

The most important problems in the multi-agent system are to accomplish a goal through the efficient coordination of several agents and to prevent collision with other agents. In this paper, we propose a new control strategy for succeeding the goal of the prey pursuit problem efficiently. Our control method uses reinforcement learning to control the multi-agent system and consider the distance as well as the space relationship between the agents in the state space of the prey pursuit problem.

• Journal of Information Technology Services
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• v.11 no.4
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• pp.69-85
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• 2012

This paper analyzes how IT adoption affects differently on the shippers' make-buy decision, depending on the changes through agency and coordination problems. Empirical findings are consistent with the theoretical predictions on the changes of shippers' decision, summarized as follows. First, while the adoption of agency-cost reducing IT leads to the increase in the proportion of private fleets, the adoption of coordination-cost reducing IT leads to the increase in proportion of for-hire carriage. Second, the extent of private fleets changes depends on the primary product type that trucks load, with products of important service task experiencing more increase. Third, the extent of for-hire carriage changes depends on the truck's trip distance, with long-trip trucks experiencing more increase. With the results, we present different policy implications from the conventionally advocated ones.

• ETRI Journal
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• v.44 no.4
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• pp.531-542
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• 2022

With the increasing demand for unlicensed spectrum, several regulators have been opening up the 6-GHz band for unlicensed use while ensuring compliance with the technical requirement to avoid harmful interference in the existing primary services (PSs). In this paper, we present two methodologies, a channel-based method and a frequency-based method, which are applicable to a frequency coordination system that calculates the permissible transmit power in the channels or frequencies available to a secondary service (SS). In addition, we have demonstrated that the available transmit power of an SS can be maximized by adjusting the power allocation of the assigned resource units under the condition that the channel of the SS is partially overlapped with that of the PS. Based on the analysis results, it is suggested that it would be better to utilize the two methods selectively according to the operating channel conditions of the PS and the SS.

• 한국디지털정책학회:학술대회논문집
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• 2004.05a
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• pp.383-400
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• 2004

Knowledge management is an essential part for gaining competitive advantage. The knowledge management system deals with information gathering, process, and implementation for the organizational performance advantage. The study integrates knowledge management in view of an internal organizational information processing structure and external strategic issue management system. This means that the coordination between internal systematic process and external scanning mechanism is essential for organizational success.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.268-271
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• 2000

Based on the rapid development of information technology (IT) including networks, manufacturing environment faces more customer engagement, global collaboration, greater emphasis on agility, increasing reach and connectivity through world-wide web, and micro transaction tracking and intelligence to name a few. The new ideas of manufacturing concept, eManufacturing is discussed in view of IT. In specific, a framework to identify. IT application in the product realization process and collaboration and coordination to implement eManufacturing is proposed.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1564-1566
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• 2004

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.137-139
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• 2006