• Journal of Korean Institute of Industrial Engineers
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• v.42 no.1
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• pp.30-37
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• 2016

A multi-server queueing system with an infinite buffer and impatient customers is analyzed. The system operates in the finite state Markovian random environment. The number of available servers, the parameters of the batch Markovian arrival process, the rate of customers' service, and the impatience intensity depend on the current state of the random environment and immediately change their values at the moments of jumps of the random environment. Dynamics of the system is described by the multi-dimensional asymptotically quasi-Toeplitz Markov chain. The ergodicity condition is derived. The main performance measures of the system are calculated. Numerical results are presented.

• Industrial Engineering and Management Systems
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• v.15 no.2
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• pp.123-130
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• 2016

We introduce a queueing system with general arrival stream and exponential service time under the N-policy, where customers may renege during idle period and arrival rates may vary according to the server's status. Probability distributions of the lengths of idle period and busy period are derived using absorbing Markov chain approach and a method to obtain the optimal control policy that minimizes long-run expected operating cost per unit time is provided. Numerical analysis is done to illustrate and characterize the method.

• Annual Conference of KIPS
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• 2001.10b
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• pp.1431-1434
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• 2001

E-Business 성공은 기존의 제품 마케팅 차원을 넘어서 전자상거래를 비롯한 기반 IP 기술의 지원과 관리에 있다. 새로운 e-Business를 시작하는 대부분의 중소형사업자는 e-Business Outsourcing Value Chain을 이용하여 서비스를 제공하고 있으며, 그중 가장 중요한 카운터 파트너로서 Web HSP를 들고 있다. 본 논문에서는 Web HSP와 사용자사이에서 제공되는 웹서비스의 새로운 패러다임에서 SLA 구조와 컴포넌트를 Network, Hosting, Application, Management 관점에서 정의하고, 이를 관리하기 위한 SLA Management 구조를 제시하였다. 본 논문의 결과로 고객은 자신의 사업에 적합한 SLA 파라미터를 제시하는 Web HSP를 찾게 될 것이며, Web HSP는 고객에게 필요한 SLA의 컴포넌트 제공과 효율적인 관리 기능을 수행함으로 서비스의 경쟁력을 얻게 될 것이다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.10-26
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• 2005

In our model, we keep inventory to satisfy uncertain demands which arrives irregularly. In this situation, we have additional two constraints. First, we need to have certain amount of order consolidation (consolidation constraint) for the orders to replenish the inventory because of production or purchase constraint. And also, if we order at a certain date which was set by administrative convenience, we have amount constraint to order the consolidated order demands (capacity constraint). We showed this variant inventory policy is needed in steel industry and note that there will be possible similar case in industry. To deal with this case, we invented a variant replenishment policy and show this policy is superior to other possible polices in the consolidation constraint case by extensive simulation. And we derive a combined solution method for dealing with the capacity constraints in addition to the consolidation constraints. For this, we suggest a combined solution method of integer programming and simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.261-264
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• 2018

2017년 비트코인을 비롯한 암호화폐 열풍이 뜨겁게 강타하면서 이를 구현하는데 활용된 블록체인(Blockchain) 기술이 주목받기 시작했다. 분산원장 기술(Distributed Ledger Technology)을 기반으로 만들어진 블록체인의 가장 큰 장점은 보안성을 높일 수 있다는 것이다. 이 기술을 챗봇(Chatbot) 개발에 접목시켜 크래커(Cracker)의 공격에 효율적으로 대응할 수 있고, 고객의 개인정보를 한 단계 더 안전하게 관리할 수 있다. 이러한 기술은 다양한 분야 중에서도 특히 데이터를 기반으로 발전하는 기술에 활용 가능성이 높을 것으로 전망되며, 이 논문에서는 블록체인 기술이 챗봇에 적용된 사례에 대해 분석한다.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.377-377
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• 2006

Alkoxyamine and thiocarbonyl thio end capped polyethylene (PE) chains were synthesized using a direct and simple approach consisting in reacting di(polyethylenyl)magnesium (PE-Mg-PE) chains with a range of nitroxides and disulfides of thiocarbonyl thio compounds. PE-Mg-PE compounds were prepared by a catalyzed chain growth reaction of ethylene on nbutyloctylmagnesium (BOMg) with a neodymocene complex $(C_{5}Me_{5})_{2}NdCl_{2}Li(OEt_{2})_{2}$. Complete characterizations confirm the introduction of the desired end groups. The controlled radical polymerization (NMP and RAFT) of butyl acrylate mediated by these functional polyethylenes was successful.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.161-170
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• 2010

In Korea, food material industry encounters the emerging market which results from the growth of food service industry and food processing industry. Food material suppliers think that the total sales in Korean market may be around 20 trillion won. However, very small numbers of studies about Korean food material industry have been conducted. This paper analyzes the current status of food material industry and the market structure in Korea, and presents several suggestions for the development of Korean food material industry as following: building up the function of fresh-cut in production area, improving market structure, settling down the cold-chain system, enforcing the certification program for food safety.

• Journal of information and communication convergence engineering
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• v.8 no.5
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• pp.513-518
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• 2010

This paper proposes a medium access control protocol for integrated voice and data services in slotted CDMA systems. The proposed protocol, which is named as RCSSMA (Reservation Code and Status Sensing Multiple Access), adopts a code reservation and status sensing schemes. RCSSMA protocol gives higher access priority to the voice traffic than data traffic for reducing the packet dropping probability. The voice terminal reserves an available spreading code to transmit voice packets during a talkspurt, whereas the data terminal transmits a packet over one of the available spreading codes that are not reserved by the voice terminals. In this protocol, the voice packets never contend with the data packets. Packet dropping probability and average data packet transmission delay are analyzed using a Markov chain model.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.548-555
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• 2003

Customer satisfaction level is usually measured in terms of price, quality, customization, after-sale-service, product variety etc. Each finn sets up a distinctive production/marketing strategy to gain competitive advantage by prioritizing the customer satisfaction measures. The market differentiation strategy directly results in supply chain performance such as lead time, inventory, customer fill rate and market share. Product proliferation desirable in customization sense often conflicts the economies of scale effect in production side. This paper focuses the relationship between product variety and market share. Specifically, we investigate how introduction of new product affects the current market share, i.e.,) formation of customer preference and provide some insight into the optimal range of product variety.

• Parasites, Hosts and Diseases
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• v.40 no.1
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• pp.33-40
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• 2002

Attempts were made to isolate and identify Korean bovine Babesia parasite. Blood samples were collected from Holstein cows in Korea. and Babesia parasites were propagated in SCID mice with circulating bovine red 1)food cells for isolation. The isolate was then antigenically and genotypically compared with several Japanese isolates. The Korean parasite was found to be nearly identical to the Oshima strain isolated from Japanese cattle, which was recently designated as Babesia ovata oshimensis n. var. Haemaphusalis longicornis was the most probable tick species that transmitted the parasite .