• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.12
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• pp.94-100
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• 2011

TCMS is the most important controller in the subway train for reliable train control and service oriented flexibility. TCMS software charges communications and control of train and maintains control devices so we use QNX for real-time control. This paper introduces overall software development of TCMS using various diagrams. Software implementation details in TC and CC are explained using deployment diagram through train configuration. Driving control process among many processes is focused to present implement details which controls train by driver or automatic train operation and handles commands to control deriving devices in cars. Reliable operation of train and easy maintenance process is achieved through the same hardware in train control computer and car control computer.

• Journal of Multimedia Information System
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• v.1 no.1
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• pp.23-43
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• 2014

With the rapidity of the development on electronic technology, various mobile devices are produced to make human life more convenient. The user is always in constant search of middle with ease of deployment. Therefore, the development of infrastructure and application with ubiquitous nature gets a growing keen interest. Recently, the number of pervasive network services is expanding into ubiquitous computing environment. To get desired services, user presents personal details about this identity, location and private information. The information transmitted and the services provided in pervasive computing environments (PCEs) are exposed to eavesdropping and various attacks. Therefore, the need to protect this environment from illegal accesses has become extremely urgent. In this paper, we propose an anonymous authentication and access control scheme to secure the interaction between mobile users and services in PCEs. The proposed scheme integrates a biometric authentication in PKI model. The proposed authentication aims to secure access remote in PCE for guaranteeing reliability and availability. Our authentication concept can offer pervasive network service users convenience and security.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.491-498
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• 2000

QFD (Quality Function Deployment) was defined by the American Supplier Institute in 1987 as a system for translating consumer requirements into appropriate company requirements at every stage, from research, through product design and development, to manufacture, distribution, installation, and marketing, sales and services. Although QFD has complex and tedious procedure to complete, it has now been In use in the world for at least IS years because QFD enables us to catch a lot of fruitful information on the given system. The objective of this paper is to provide and analyze the trend on the choice of subject courses of university students using QFD. The data are collected by questionnaires. The samples for this study are randomly chosen from the universities in Seoul, Kangnung, and Samchok during 3 months (2000. 3 ~ 2000. 5) The results of this study will play an important role not only for service of students but also for opening of subject courses.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.278-281
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• 2004

현재 무선랜은 무선 인터넷 솔루션 중의 가장 효율적인 무선 접속 수단으로 이용되고 있다. 그러나 본래 개인적인 용도로 설계된 무선랜의 용도와는 달리, 무선랜이 기업 및 대규모 핫스팟에 설치되기 시작하면서 그동안 고려하지 못한 여러 가지 점이 드러나기 시작했다. KT에서는 2002년부터 NESPOT으로 불리는 무선 인터넷 서비스를 시작하면서, 많은 핫스팟 및 대규모 회의장에 무선랜을 구축하고 있다. 본 논문에서는 일반적인 무선랜 설치 방안에 대해 논의하고, 그 실례로 이번 3월 달에 열린 제 59차 IETF 회의에서 무선랜을 구축한 사례를 보이고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.323-336
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• 2000

In order to achieve the deployment of B-ISDN services in a short time, B-ISDN is being combined with terrestrial ATM network and satellite network which covers a widespread service range. This paper analyzes and investigates several previously existent CDV compensation methods in order to compensate CDV arising from interfacing satellite TDMA and ATM. Specifically to supplement the problems of timestamp and cell number counting methods, new Partial Timestamp mechanism for CDV compensation is proposed. The CDV compensating efficiency of the proposed mechanism is analyzed and evaluated by simulations. It goes to show that Partial timestamps mechanism has many advantages in the aspect of the CDV compensation.

• Journal of information and communication convergence engineering
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• v.16 no.1
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• pp.6-11
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• 2018

It is important to find the random estimation points in wireless sensor network. A link quality indicator (LQI) is part of a network management service that is suitable for a ZigBee network and can be used for localization. The current quality of the received signal is referred as LQI. It is a technique to demodulate the received signal by accumulating the magnitude of the error between ideal constellations and the received signal. This proposed model accepts any number of random estimation point in the network and calculated its nearest anchor centroid node pair. Coordinates of the LQI sphere are calculated from the pair and are added iteratively to the initially estimated point. With the help of the LQI and weighted centroid localization, the proposed system finds the position of target node more accurately than the existing system by solving the problems related to higher error in terms of the distance and the deployment of nodes.

• Journal of Communications and Networks
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• v.12 no.2
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• pp.181-190
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• 2010

A multitude of overlay network designs for resilient routing, multicasting, quality of service, content distribution, storage, and object location have been proposed. Overlay networks offer several attractive features, including ease of deployment, flexibility, adaptivity, and an infrastructure for collaboration among hosts. In this paper, we explore cooperation among co-existing, possibly heterogeneous, overlay networks. We discuss a spectrum of cooperative forwarding and information sharing services, and investigate the associated scalability, heterogeneity, and security problems. Motivated by these services, we design Synergy, a utility-based overlay internetworking architecture that fosters overlay cooperation. Our architecture promotes fair peering relationships to achieve synergism. Results from Internet experiments with cooperative forwarding overlays indicate that our Synergy prototype improves delay, throughput, and loss performance, while maintaining the autonomy and heterogeneity of individual overlay networks.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.43-46
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• 2006

IEEE 802.16 WirelessMAN aiming to broadband wireless access (BWA) is evolving to 4G mobile communication system through the standardization of IEEE 802.16e supporting mobility on existing fixed WirelessMAN system. It is necessary for hand-over to provide seamless data service while MS (Mobile Station) moves to another BS (Base Station). Because the performance of handover affects packet loss or delay of any communications, it must consider low latency handover mechanism in packet based network. In this paper, we describes handover scheme of IEEE 802.16e with the cell edge interference problem and shows the way to solve the problem in frequency reuse one deployment. Our scheme reduces the handover latency and packet loss probability.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1340-1346
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• 2014

Previous studies of reliable server assignment considered only to assign the same cost of server, that is, homogeneous servers. In this paper, we generally deal with reliable server assignment with different server costs, i.e., heterogeneous servers. We formulate this problem as a nonlinear integer programming mathematically. Our problem is defined as determining a deployment of heterogeneous servers to maximize a measure of service availability. We propose two metaheuristic algorithms (tabu search and particle swarm optimization) for solving the problem of reliable server assignment. From the computational results, we notice that our tabu search outstandingly outperforms particle swarm optimization for all test problems. In terms of solution quality and computing time, the proposed method is recommended as a promising metaheuristic for a kind of reliability optimization problems including reliable sever assignment and e-Navigation system.

• The Journal of Information Systems
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• v.16 no.2
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• pp.93-122
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• 2007

RFID has fundamental influences on today's business management. This research seeks to formulate the opportunities and challenges, the strengths and weaknesses and the perceived benefits of RFID implementation in three industries: manufacturing, medical-service, and distribution. Ten companies of successful RFID deployment in Korea are presented. Field interview and panel discussion were used to explore the research purpose. The core challenges include RFID readability issues, lack of best practices, increasing prime cost, visible ROI, implementation cost, and employee's resistance. The strengths include IT infrastructure, system integration competency, RFID business model creation ability, executive's support. There is little weakness in Korea companies, there are many perceived benefits in three industries. The most distinctive finding is that the visible ROI was found out in the manufacturing industry, not in the distribution industry. The opportunities and challenges, the strengths and weaknesses and the perceived benefits are some different in three industries, which provide valuable guidance for Korean companies in seeking the RFID opportunities. This case study represents a pioneer research of RFID adoption in Korea.