• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.24-33
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• 2007

In this paper, two different dynamic cell coordination strategies for frequency flat and selective fading are proposed for efficient subcarrier allocation in the joint consideration of adaptive modulation and variable frequency reuse in the channel-aware OFDMA downlink multicellular environment. Compared to a conventional OFDMA system without cell coordination, where system throughput may become degraded due to the persistent interference from other cells, the proposed system dynamically allows RNC to apply different reuse factors on each subchannel and scheduling in consideration of channel and interference conditions of individual users so as to increase the system throughput and guarantee QoS of each user. In a frequency flat fading, the dynamic scheme with the proposed scheduling achieves on average three times larger throughput than the conventional dynamic scheme [8]. In a selective fading channel, the proposed schemes showed 2.6 times as large throughput as that of a single reuse factor of one for all subchannels.

• Industrial Engineering and Management Systems
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• v.13 no.3
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• pp.304-318
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• 2014

It is necessary for a retailer to improve responsiveness to uncertain customer demand in product sales. In order to solve this problem, this paper discusses an optimal operation for a 2-stage-ordering-production system consisting of a retailer and a manufacturer. First, based on the demand information estimated at first order time $t_1$, the retailer determines the optimal initial order quantity $Q^*_1$, the optimal advertising cost $a^*_1$ and the optimal retail price $p^*_1$ of a single product at $t_1$, and then the manufacturer produces $Q^*_1$. Next, the retailer updates the demand information at second order time $t_2$. If the retailer finds that $Q^*_1$ dissatisfies the demand indicated by the demand information updated at $t_2$, the retailer determines the optimal second order quantity $Q^*_2$ under $Q^*_1$ and adjusts optimally the advertising cost and the retail price to $a^*_2$ and $p^*_2$ at $t_2$. Here, decision-making approaches for two situations are made-a decentralized supply chain (DSC) whose objective is to maximize the retailer's profit and an integrated supply chain (ISC) whose objective is to maximize the whole system's profit. In the numerical analysis, the results of the optimal decisions under DSC are compared with those under ISC. In addition, supply chain coordination is discussed to adjust the unit wholesale price at each order time as Nash Bargaining solutions.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.33-39
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• 2014

Chemical accidents are the cause of the accident site during the initial responders to quickly and easily see materials and concentration method for the U.S. Environmental Protection Agency(EPA) is widely used in the initial response team direct reading detection equipment used. Ministry of the tubular gas detection equipment to detect direct reading detection equipment used in the event of an accident scene, and shell-and-tube gas detector for rapid detection and identification and precise analysis of causative pollutants before about strategically can identify the quantitative and qualitative useful equipment. However, those who initially respond to the scene of a direct reading detection equipment and a simple lack of understanding of how to use the numbers only because of the way you want to check the accuracy of detection results have been raising questions about the increase. The scene of the accident in order to obtain an accurate detection results used in this paper, the Ministry of Environment of gas detectors detect tubular Kitagawa and Draeger detector tube to check the reactivity of the material on-site detection of early response of those who were to raise the accuracy of the results.

• Journal of Fashion Business
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• v.18 no.1
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• pp.66-79
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• 2014

The study analyzed differences in lifestyle, self-esteem, body satisfaction, physical self efficacy, self-confidence in fashion coordination between participants and non-participants of a senior model education program. Another purpose of the study was to examine differences between the participants with less and longer than 6 months of the education. The questionnaire developed by the researchers was collected from 200 participants aged between 50s and 70s. Two hundred questionnaires were used in the final analysis. The data were analyzed by common factor analysis, and independent sample t-test using SPSS 180.0/Windows. The results demonstrated significant differences in lifestyle, self-esteem, body satisfaction, physical self efficacy, self-confidence in fashion coordination between the participants and non-participants. The participants showed significant higher scores in lifestyle, self esteem, body satisfaction, physical self efficacy, self-confidence in fashion coordination. Also, there were significant differences in personal satisfaction in lifestyle, body satisfaction, and learning efficacy between the participants depending on the period of the education; the participants with longer than 6 months of education showed significantly higher scores in the factors than the participants who took less than 6 months of education.

• The Journal of Korean Medicine
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• v.27 no.1 s.65
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• pp.196-203
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• 2006

Objectives : The aim of this study is to investigate how does the methods of treatment and diagnosis of Traditional Korean Medicine(TKM) get the evidence of efficacy and safety and what type of efficient body and appropriate facility of the coordination center for clinical trial in TKM. Methods : We have got the information of clinical trial center or clinical collaboration center by site invitation, search of paper and reports and internet exploration for the domestic or foreign site. Results : Coordination center for clinical trial usually involves every steps of clinical trials, such as development of Case Report From (CRF), design of study, calculation of sample size, randomization, maintenance of blinding, monitoring and audit of the resource document, data and CRF, data entry, quality control of data, analysis and report. Conclusions : The body needs several aresa of experts, which are epidemiologists, biostatisticians, research nurses for coordination, data manager and programmer, and administrator. This body would be enhance and help he clinical researches including clinical trials in TKM.

• Industrial Engineering and Management Systems
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• v.14 no.2
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• pp.111-121
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• 2015

A correct information of customer returns ratio under e-commerce is not always shared between supply chain (SC) members. Also, it is important issue for SC members to handle the unsold products in a market. This paper discusses the impact of information sharing of customer returns ratio on an optimal sales strategy including resale of customer returns and buyback policy for a SC under e-commerce with a manufacturer and a retailer. A retailer sells a single product and resells the resalable customer returns in the same market. A manufacturer produces the products and buys back the unsold products as to their quality from the retailer. The integrated SC (ISC) determines the optimal product order quantity to maximize the expected profit of the whole SC. The decentralized SC (DSC) makes the optimal decisions for order quantity and the wholesale price of products to maximize the expected profit of each SC member. The effect of information sharing is discussed between SC members under ISC and DSC. The analysis numerically investigates how information sharing of the returns ratio affects the optimal decision and the expected profits under ISC and DSC. Besides, effect of SC coordination to encourage the shift to ISC is discussed.

• Journal of the Korea Society of Computer and Information
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• v.22 no.2
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• pp.9-19
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• 2017

Useful continuous sensing applications are increasingly emerging as a new class of mobile applications. Meanwhile, open, multi-use sensor devices are newly adopted beyond smartphones, and provide huge opportunities to expand potential application categories. In this upcoming environment, uncoordinated use of sensor devices would cause severe imbalance in power consumption of devices, and thus result in early shutdown of some sensing applications depending on power-hungry devices. In this paper, we propose EnergyCordy, a novel inter-device energy use coordination system; with a system-wide holistic view, it coordinates the energy use of concurrent sensing applications over multiple sensor devices. As its key approach, we propose a relaxed sensor association; it decouples the energy use of an application from specific sensor devices leveraging multiple context inference alternatives, allowing flexible energy coordination at runtime. We demonstrated the effectiveness of EnergyCordy by developing multiple example applications over custom-designed wearable senor devices. We show that EnergyCordy effectively coordinates the power usage of concurrent sensing applications over multiple devices and prevent undesired early shutdown of applications.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.119-128
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• 2009

In this paper, we analyze the effect of the data aggregation level on the MAC performance when RFID (Radio Frequency Identification) logistics data, which can be aggregated at RFID readers to reduce the transmission overhead, are transmitted in IEEE 802.11 wireless LANs. For various data aggregation levels, the throughputs and latencies of the DCF (Distributed Coordination Function) and PCF (Point Coordination Function) MAC protocols are analyzed by computer simulation. From the simulation analysis, we propose the appropriate input traffic load for real-time RFID logistics data transmitted in IEEE 802.11 wireless LANs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.7
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• pp.352-357
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• 2005

In competitive electricity markets, the System Operator (SO) coordinates the overall maintenance schedules when the collective maintenance schedule reported to 50 by Gencos not satisfy the specified operating criteria, such as system reliability or supply adequacy. This paper presented a method that divides generator maintenance scheduling of the 50 into a master-problem and a sub-problem. Master-problem is schedule coordination and sub-problem is DC-optimal power flow. If sub-problem is infeasible, we use the algorithm of modifying operating criteria of master-problem. And, the 50 should use the open information only, because the information such as cost function of a generator and bidding Price is highly crucial for the strategies of profit maximization.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.05a
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• pp.198-208
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• 2007

Recently business enterprises have forced to face in fierce competition in today's global markets due to the short life cycles of products and the higher expectation of customers. Together with continuing advances in communications and transportation technologies, these environments have motivated the continuous evolution of the supply chain and the management techniques. This paper consider three-echelon inventory system which consist of one manufacturer, one distributor and N retailers for a single product under assumption of constant demand. This paper propose the inventory replenishment period using heuristic method and order policy through coordination of inventory replenishment period. The simulation results show that decrease the total cost of the three-echelon inventory system.