• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.260-264
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• 2003

Among many factors to affect the network performance, this paper analyses how the buffer size of NIC(Network Interface Card) can affect web server and LAN(Local Area Network). We use the ns-2 which is defacto network simulation tool to observe the changes in drop rate, throughput, RTT(Round Trip Time), effective throughput depending on varying buffer sizes. And we analyse the effect of NIC buffer size on the web traffic in Ethernet.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.76-87
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• 2014

Today the energy consumption of ICT networks is about 10% of the worldwide power consumption and is predicted to increase remarkably in the near future. For this reason, this paper studies energy saving strategies assuring the network-level QoS. In the strategies, the energy consumption of NIC(network interface card) on both endpoint of links decreases by selecting links and making them sleep when the total traffic volume of the IP network is lower than a threshold. In this paper, we propose a heuristic routing algorithm based on so-called delegating/delegated routers, and evaluate its characteristics using computer simulation considering network-level QoS. The selection of sleep links is determined in terms of the number of traffic paths (called min_used path) or the amount of traffics(called min_used traffic) through those kinks. To our experiment, the min_used traffic method shows a little better energy saving but the increased path length compared to the min_used path method. Those two methods have better energy saving characteristics than the random method. This paper confirms that the delegating/delegated router-based routing algorithm results in energy saving effects and sustains network-level QoS in IP networks.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.50-60
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• 2009

Recently, the traffic card is gradually utilized and its several supplementary services have been significantly developed. Particularly, since it is possible to pay fees for buses, taxies, subways, parking and tollgates with only one traffic card, new payment method for economically processing has been focused. This paper presents a new receipt management system which allows possibly paying with several digital cards through PC interfacing terminals. The proposed system is mainly composed of three parts: terminals, middleware, and management servers. A terminal part includes processing module for payment/charging and credit/check/debit cards, etc and its operation is fulfilled through a middleware part. A main task of a middleware part is to connect a terminal part to managing servers through middleware applications. Additionally, processing of several receipt items and monitoring of the terminals to product statistical reports based on the processed result are carried out in the middleware. A management sever part is accomplished for collecting all of transaction histories against users and charging items over allowed province and managing statistical information. The proposed system is currently utilized in the Nam-GU district office and the Nam-GU district health center, Busan, S. Korea, respectively for testing its effectiveness. We conclude from this demonstration that the system is more useful and efficient than the previous processing method especially in that variable payment ways are provided and consumption burden is reduced.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.1-11
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• 2007

Seoul's transportation system was changed drastically starting the first of June in two thousand. This policy includes integrated distance-based fare system and public transportation card system called smart card. Especially, as public transportation card data contains individual travel, transfer and using modes information it is possible to catch the characteristics of path-based individuals and mass transit. Thus, public transportation card data can contribute to evaluate the mass transit service in integrated public transportation networks. In addition, public transportation card data are able to help to convert previous researches and analyses with link-based trip assignment models to path-based mass transit service analysis. In this study, an algorithm being suitable for path-based trip assignment models is suggested and proposed algorithm can also contribute to make full use of public transportation card data. For this, column generation algorithm hewn to draw the stable solution is adopted. This paper uses the methodology that is to take local approximate equilibrium from partial network and expand local approximate equilibrium to global equilibrium.

• Proceedings of the CALSEC Conference
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• 1999.11a
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• pp.798-812
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• 1999

최근의 급격한 전자상거래 시장의 확대는 21세기 기업의 생존전략으로 부각되고 있으며, 각 기업에서 적극적으로 추진되고 있다. 이러한 전자상거래가 활성화되기 위해서는 사이버 스페이스상에서 현금과 동일한 기능을 수행하는 화폐가 필요하다. 이렇게 전자상거래에서 통용 가능한 화폐를 디지털 화폐(Digital Cash)라고 하며, 전자상거래 구현을 위한 핵심 기술이 된다. 디지털 화폐에 관한 기술 개발 및 사용에 관한 검토는 이미 미국, 일본 등을 중심으로 적극적으로 추진되고 있으며, 상업적으로도 충분히 성공하는 사례가 제시되고 있다. 본 연구에서는 전자상거래 활성화를 위한 디지털 화폐의 활용에 관한 연구로, 현재 부산에서 성공적으로 수행되고 있는 디지털 화폐인 “하나로교통카드(HANARO Traffic Cand)”를 중심으로 디지털 화폐의 성공 가능성에 대하여 검토한다. 여기에서는 하나로교통카드 추진 배경 및 추진 경위, 하나로교통카드의 성공 요인 분석 등을 수행하여, 향후 디지털 화폐가 전자상거래에서 성공할 수 있는 방안에 대하여 검토한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.2 s.5
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• pp.55-68
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• 2004

On this research, Contingent Valuation Method which is universally applicable to non market goods and being developed in a field of the environmental economics is used to estimate appropriate value of freeway traffic information. Imaginary scenario is designed to estimate appropriate value of freeway traffic information and major in traffic-related field is used & man-to-man interview carried out to enhance a reliance of questionnaire. Open-ended question and a way of payment card are in use each other. make use of Multiple Regression Model in Contingent Valuation Method of traffic information and find an effect on the value of the traffic information. As a result of research, intention to pay for usage per information is regarded as a somewhat higher but monthly cost is lower than they have to. It is concluded that value and usefulness of the individual information is nod in approval but a majority of user's recognition that publish information must be provided free of charge lowers intention of payment.

• The Journal of Society for e-Business Studies
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• v.27 no.2
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• pp.193-204
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• 2022

Smart card data is representative mobility data and can be used for policy development by analyzing public transportation usage behavior. This paper deals with the problem of classifying metro stations using metro usage patterns as one of these studies. Since the previous papers dealing with clustering of metro stations only considered traffic among usage behaviors, this paper proposes clustering considering traffic time as one of the complementary methods. Passengers at each station were classified into passengers arriving at work time, arriving at quitting time, leaving at work time, and leaving at quitting time, and then the estimated shape parameter was defined as the characteristic value of the station by modeling each transit time to Weibull distribution. And the characteristic vectors were clustered using the K-means clustering technique. As a result of the experiment, it was observed that station clustering considering pass time is not only similar to the clustering results of previous studies, but also enables more granular clustering.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.459-462
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• 2008

By using RFID technology in order to manage public traffic management, RFID system and middleware software with PXA255 ARM chip is developed and is capable of operating the traffic card. The developed RFID system consists of 13.56MHz RFID R/W, wireless LAN (IEEE802.11.a/b), Wibro (IEEE802.16), TFT-LCD to display information, and embedded system to collect a charge information, etc. By applying developed system, basic infra-structure capable of supporting various service of u-Traffic can be effectively applied.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.663-671
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• 2016

This paper investigates how to change passengers' preferences for express trains according to line extension in Seoul Metro Line 9. Before-and-after line extension, we traced passengers' path choices using Smart Card data via the method suggested by Kim et al. (2015). We developed two multinomial logit models before-and-after line extension. Transferability test showed that there is no difference between the two models. However, the load factor of the express train increased by 6.7% and the gap between the local and express trains became significantly wider.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2062-2068
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• 2008

In a u-City project in Busan, public transportation which is one of ITS has been considered. RFID system embedded with PXA255 chip and middleware capable of communicating a server side was developed. To perform data communication link with traffic card, developed system consists of wireless modules that are wireless LAN (IEEE802.11a/b and IEEE802.16. Using developed RFID system and middleware, it is expected that this system becomes a basic infrastructure to support a service of u-Traffic for u-City construction.