• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1589-1595
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• 2010

China has experienced rapid economic growth and burgeoning trade since it began economic reforms and an opening policy. With this the amount of marine cargoes between Korea and China had been increased Recently this increasing rate of cargoes, the development of the Yellow Sea Sub-Region and the change of the Northeast Asian logistics network have acted as important factors of Korea's strategy to be the Northeast Asian logistics hub. This paper analyzes China's inland transport network to offer basic understanding on transport and logistics network in China. Therefore, the outcomes of this paper could be used as basic materials to further transport and logistics cooperation between China and Korea and to developing a more realistic plan to complete Korea's Northeast Asia logistics hub strategy.

• 한국컴퓨터정보학회논문지
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• 제22권10호
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• pp.93-100
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• 2017

Current internet has evolved from the sharing and efficiency aspects of information, it is still vulnerable to the fact that the Internet is not secure in terms of security and is not safe to secure of security mechanism. Repeating patches on continuous hacking are continuously demanding additional resources for network or system equipment, and consequently the costs continue to increase. Businesses and individuals alike are speeding up the damage caused by crime like of ransomware, not jusy simple attacks, and businesses and individuals need to respond to cyber security. In addition, the ongoing introduce of security device, and separate of networks for secure transmission of contents in the existing TCP/IP system, but it is still lacking in security. To complement the security implications of this existing TCP/IP Internet Protocol, we intend to propose a Secure Contents Transport System (SCTS) on the network using the CCN concept.

• 한국통신학회논문지
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• 제21권10호
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• pp.2687-2702
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• 1996

It is desirable that the implementation of next generation information infrastructure is the Integrated Network combining the satellite and the terrestrial network. The application of the ATM network being the dominant infrastrure of terrestrial network to the satellite network is being studied variously. Considering these concepts, this paper analyzes due to ATM transport via satellite, evaluates the degradation of QoS and proposes reliable method of ATM cell transport via satellite. Because ATM is investigated with the optical fiber which is almost error free characteristics, the practical application of ATM transport via satellite essentially need the channel coding(FEC:Forward Error Correction) to enhance BER performance. But using the FEC coding, satellite link has burst error characteristics which evoke severe performance degradation fo ATM QoS. Therefore in satellite link, we analyze burst error characteristics using experimental results of computer simulation. Then to compensate these characteristics, based on this analysis and HEC dual mode algorithm we propose various interleaver structures(Block interleaver, Intra interlever, and Inter-Intra interleaver) to improve cell transmission QoS. We execute performance evaluations of iterleaver structures by computer simulation.

• 한국인터넷방송통신학회논문지
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• 제15권3호
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• pp.59-65
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• 2015

최근 네트워크 산업계에서 기존 전송 망 보다 유연한 망을 구축하기 위한 캐리어이더넷 기술이 부각되고 있으며 MPLS-TP (MultiProtocol Label Switching-Transport Profile) 기술이 해당 영역의 주요 표준 기술로 적용되고 있다. 하지만 MPLS-TP 망내의 장비를 관리하기 위한 관리 망에 대해서는 명확하지 않은 상태이다. 본 논문에서는 MPLS-TP 망 내의 장비 설치 시 부가적 설정 없이 자동으로 관리 망을 구축하는 방안을 제안한다. 제안하는 방법으로 관리시스템과 망 연결을 위한 설정을 최소화 하여 망 내의 장치 설치비용과 유지 관리 비용을 감축할 수 있다. 또한 실제 MPLS-TP 장비에 적용하여 제안하는 방법의 실효성에 대해 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3711-3730
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• 2014

Cognitive radio networks (CRNs) have emerged as a promising solution to enhance spectrum utilization by using unused or less used spectrum in radio environments. The basic idea of CRNs is to allow secondary users (SUs) access to licensed spectrum, under the condition that the interference perceived by the primary users (PUs) is minimal. In CRNs, the channel availability is uncertainty due to the existence of PUs, resulting in intermittent communication. Transmission control protocol (TCP) performance may significantly degrade in such conditions. To address the challenges, some transport protocols have been proposed for reliable transmission in CRNs. In this paper we survey the state-of-the-art transport protocols for CRNs. We firstly highlight the unique aspects of CRNs, and describe the challenges of transport protocols in terms of PU behavior, spectrum sensing, spectrum changing and TCP mechanism itself over CRNs. Then, we provide a summary and comparison of existing transport protocols for CRNs. Finally, we discuss several open issues and research challenges. To the best of our knowledge, our work is the first survey on transport protocols for CRNs.

• Journal of Communications and Networks
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• 제11권3호
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• pp.287-296
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• 2009

Although asymptotic bounds of wireless network capacity have been heavily pursued, the answers to the following questions are still critical for network planning, protocol and architecture design: Given a three-dimensional (3D) network space with the number of active users randomly located in the space and using the wireless communication technology, what are the expected per-flow throughput, network capacity, and network transport capacity? In addition, how can the protocol parameters be tuned to enhance network performance? In this paper, we focus on the ultra wideband (UWB) based wireless personal area networks (WPANs) and provide answers to these questions, considering the salient features of UWB communications, i.e., low transmission/interference power level, accurate ranging capability, etc. Specifically, we demonstrate how to explore the spatial multiplexing gain of UWB networks by allowing appropriate concurrent transmissions. Given 3D space and the number of active users, we derive the expected number of concurrent transmissions, network capacity and transport capacity of the UWB network. The results reveal the main factors affecting network (transport) capacity, and how to determine the best protocol parameters, e.g., exclusive region size, in order to maximize the capacity. Extensive simulation results are given to validate the analytical results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1406-1424
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• 2017

Recent advancements in network infrastructures provide increased opportunities to support data delivery over multiple paths. Compared with multi-homing scenario, overlay network is regarded as an effective way to construct multiple paths between end devices without any change on the underlying network. Exploiting multipath characteristics has been explored for TCP with multi-homing device, but the corresponding exploration with overlay network has not been studied in detail yet. Motivated by improving quality of experience (QoE) for reliable data delivery, we propose a multipath message transport protocol based on application level relay (MPMTP-AR). MPMTP-AR proposes mechanisms and algorithms to support basic operations of multipath transmission. Dynamic feedback provides a foundation to distribute reasonable load to each path. Common source decrease (CSD) takes the load weight of the path with congestion into consideration to adjust congestion window. MPMTP-AR uses two-level sending buffer to ensure independence between paths and utilizes two-level receiving buffer to improve queuing performance. Finally, the MPMTP-AR is implemented on the Linux platform and evaluated by comprehensive experiments.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1872-1885
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• 2011

최근 동북아 지역의 경제 규모의 성장으로 인하여 각 국가 간 많은 교역량이 발생하고 있다. 또한 현재의 세계 경제 환경은 국가간의 교역이나 경제협력을 통하여 국가간 상호의존도가 지속적으로 높아지고 있는 실정이다. 동북아지역간은 공동시장으로서의 기능을 추구하고 있으며, 향후 지역간 경제 활동은 더욱 유기적인 관계로 발전할 것으로 보인다. 이러한 여건에서 한국의 경제가 균형적인 구조를 갖추기 위해서는 물류시설의 개선 및 운송네트워크가 점차 확대되가고 있는 중국 및 일본과의 물류네트워크 연계체계를 강화하는 것이 무엇보다 필요하다고 판단된다. 따라서 한국이 동북아 물류거점으로 발전하기 위해서는 한반도를 중심으로 하는 다양하고 효율적인 복합운송시스템을 구축하여 효율적인 네트워크 중심지로서의 역할의 정립이 중요하다고 생각된다. 따라서 본 연구는 동북아 지역의 기존의 해상운송과 새롭게 도입될 복합운송시스템 구축에 대하여 한 중 일 3국간의 물류네트워크를 시나리오별로 비용 및 시간을 분석하여 복합운송시스템의 경쟁력을 제시하고자 한다.

• 한국시뮬레이션학회논문지
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• 제17권4호
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• pp.153-158
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• 2008

SDR(Software Defined Radio)은 서로 다른 무선 전달 프로토콜간의 유동적 연동을 제공할 수 있는 솔루션이다. u-health 서비스 네트워크와 같은 여러가지 전달 프로토콜을 지원하는 센서노드들로 구성될 수 있는 다종 유비쿼터스 네트워크 환경에서, 특정 노드의 전달 프로토콜을 지원하는 AP(Access Point)로의 트래픽 집중이나, 특정 노드의 전달 프로토콜을 지원하는 AP에서의 장애 발생 또는 미설치로 인한 전달불능 등이 발생할 수 있다. 본 논문에서는 SDR 기능을 가진 노드와 혼잡 제어 기능을 가진 AP를 포함하는 다종 유비쿼터스 네트워크에서의 전달성능을 분석하기 위한 모델링 및 시뮬레이션에 대한 연구결과를 제시한다. 본 연구에서는 전달 프로토콜들의 구체적인 동작과정보다는 다종 전달 프로토콜로 구성된 네트워크에서의 유동적 연동성의 제공에 따른 전체 네트워크의 전달성능의 변화특성(dynamics)을 분석하기 위하여 DEVS(Discrete Event Systems Specification)방법론을 활용하였으며, DEVS형식론에 근거한 모델링과 DEVSim++시뮬레이션환경을 통한 분석결과를 제시하였다.

• 한국철도학회지
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• 제9권2호
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• pp.19-24
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• 2006

Green gas emissions Trading System(ETS) came into effect in the Europe last year 2005. All transport modes have tried to reduce green gas emission and EU member countries are promoting the use of environmental friendly transport mode to avoid economic loss due to green gas emission. Besides ETS, rapidly rising of oil price and peak oil urge to invest more in the environmental friendly public transport mode and to discourage the use of private cars. The operation of KTX is estimated to bring external cost reduction up to 570 bil. won in 2004 based on European external unit costs of transport modes. This result implies that the expansion of high speed rail network and reconsideration of East-West high speed rail network which is not considered because of weak economic validity is required.