• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.50-54
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• 2007

현재 국내에서 ITS(Intelligent Transport Systems) 통신방식으로 이 용되고 있는 DSRC 방식은 TTA(한국정보통신기술협회)의 기술표준으로서 대전시,전주시에 적용되어 BIS(Bus Information Service)에 이용되고 있고,최근 고속도로 ETCS(Electronic Toll Collection System)가 DSRC방식으로 전국고속도로 Tollgate 에서 2007년 연말에 개통될 예정이다. DSRC 방식은 2000년에 TTA(한국정보통신기술협회)에서 기술표준이 제정되어 현재 1Mbps 의 Data 용량을 가진다. DSRC 방식의 물리링크 변조방식은 ASK(Amplitude Shift Keying)로 ITS 확장 서비스 적용을 위해 변조방식을 QPSK(Quadrature Phase Shift Keying )로 개선하게 되면 이론적으로 4배의 Data Rate 향상이 이루어진다. 물리적인 RF 변조방식을 ASK에서 QPSK로 바꿔 간단히 Data Rate을 개선하게 되면 회로구현의 경제성이 향상되어 DSRC 응용 서비스가 활성화 될 것이다.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1212-1220
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• 2012

In this paper, a collision-free resource reservation scheme for WUSB (Wireless Universal Serial Bus) networks with WiMedia D-MAC (Distributed Medium Access Control). Since distributed characteristic of the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme may cause lots of conflicts, overall performances of the WUSB with WiMedia D-MAC can be deteriorated. In addition, when we consider multi-hop environment, "mobile" hidden node problem due to mobility of WUSB devices can be happened, and it is a critical problem to mobile WUSB devices transceiving real-time QoS (Quality of Service) traffic. To tackle the problem, we propose a new DRP reservation mechanism to prevent DRP conflicts for multi-hop mobility support in WUSB networks with WiMedia D-MAC and show its improved performance via simulation results.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.14-18
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• 2014

A recent major development in computer technology is the advent of wearable computer systems. Wearable computer systems employ a wireless universal serial bus (WUSB), which refers to a combination of USB with the WiMedia wireless technical specifications. In this study, we focus on an integrated system of WUSB over wireless body area networks (WBANs) for wireless wearable computer systems. However, current WBAN MACs do not have well-defined quality of service (QoS) mapping and resource allocation mechanisms to support multimedia streams with the requested QoS parameters. To solve this problem, we propose a novel QoS-aware time slot allocation method. The proposed method provides fair and adaptive QoS provisioning to isochronous streams according to current traffic loads and their requested QoS parameters by executing a QoS satisfaction algorithm at the WUSB/WBAN host. The simulation results show that the proposed method improves the efficiency of time slot utilization while maximizing QoS provisioning.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.605-607
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• 2011

아이폰, 구글폰 등과 같은 스마트폰들이 대중화됨에 따라 다양한 형태의 어플리케이션이 개발되고 있다. 최근 대학교에서도 학생들의 효율적인 대학생활을 위해 수강신청, 식당메뉴, 강의시간표 등에 관련된 캠퍼스 관련 어플리케이션들이 개발되고 있다. 특히, 이 중에서도 스쿨-버스 관련 서비스는 가장 인기있는 애플리케이션이지만, 대부분이 버스 시간표, 버스 노선도 등의 단편적인 정보만을 제공하고 있어서 효용성이 떨어지는 실정이다. 본 논문에서는 버스에 GPS 수신기 등의 추가 장비 설치 없이 운전기사의 스마트폰 앱에서 주기적으로 위치정보를 전송받아 스쿨버스 서비스 앱에서 실시간으로 지도상에서 학생들이 버스 위치를 파악할 수 있는 스쿨버스 서비스 어플리케이션을 설계한다.

• Journal of the Korean Society for Railway
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• v.3 no.3
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• pp.161-169
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• 2000

AGT(Automated Guide-way Transit System) was introduced to satisfy the every increasing need for improved urban transportation. The AGT system is classified as medium distance and demand capacity mass transit being introduced for such area with inadequate passenger demand for railway construction but excessive demand for bus service. To decrease initial investment cost it is important that we have to secure the technology system of Light Rail Transit for Korea environment. By utilizing the finite element analysis, the result in this paper is enough to satisfy the strength whish is required. Also for the purpose of safety, it is decided the thickness and frame structure of the undeframe section through the analysis. It is known that carbody is no problem for required design conditions.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.455-460
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• 2010

Recent increases in the road and rail infrastructure, but the urban traffic problems such as accidents, congestion are increasing. The reason is that the high cost and lack of accessibility of railway transportation, the low quality of road services, and efficient transport links, etc.. The developments of a variety of policy and technical means are being performed to solve these problems. Among them, the Bimodal Tram which is combined low-cost of bus and high service quality of railway transportation is attracting attention. In this paper, the development status of technology and efficient utilization of operational and infrastructure elements for the operational efficiency, safety and passenger comfort of Bimodal Tram is studied.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1923-1928
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• 2010

The IEC 61850 protocol proposed for the interoperability between IEDs(intelligent electronic devices) adopts the prioritized switched ethernet as its communication channel because substation bus is utilized to exchange both real-time and non real-time messages. The prioritized switched ethernet uses IEEE 802.1Q/p QoS(Quality of Service) in addition to IEEE 802.3 ethernet to enhance the real-time characteristics. However, IEEE 802.1Q/p QoS has priority-blocking problem that occurs when higher-priority frame transmission request during lower-priority frame transmission. To resolve this problem, this paper proposes P(Preemptive)-Ethernet. P-Ethernet uses the modified IEEE 802.1Q/p frame format and new priority preemption mechanism. This paper also implements P-Ethernet controller using FPGA (Virtex-4) and MicroBlaze processor. From the implementation results, P-Ethernet controller shows a improved latency and jitter of transmission period compare to the normal ethernet controller.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.77-81
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• 2006

Because of the rapid increasing of network user, there are some problems to tolerate the network overhead. Recently, the research and technology of the user-level for high performance and low latency than TCP/IP which relied upon the kernel for processing the messages. For example, there is an Infiniband technology. The Infiniband Trade Association (IBTA) has been proposed as an industry standard for both communication between processing node and I/O devices and for inter-processor communication. It replaces the traditional bus-based interconnect with a switch-based network for connecting processing node and I/O devices. Also Infiniband uses RDMA (Remote DMA) for low latency of CPU and OS to communicate between Remote nodes. In this paper, we develop the SRP (SCSI RDMA Protocol) which is Storage Access Protocol on Infiniband network. And will compare to FC (Fibre Channle) based I-SCSI (Internet SCSI) that it is used to access storage on Etherent Fabric.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.181-183
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• 1999

As one of ancillary services, voltage support and reactive power service should be compensed properly for its contribution. In this paper, a cost-based reactive power planning is presented. which minimizes the total cost of reactive power support of generators and VAR compensation facility installation. Reactive power support of generator is evaluated by the opportunity costs of reduced energy sale considering the varying SMP(system marginal price) in power market, Gradient projection method is applied to solve this reactive power planning using IEEE14 bus system.

• Journal of Sensor Science and Technology
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• v.18 no.6
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• pp.409-416
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• 2009

A lot of valuable-piece of information are acquisited through ubiquitous sensor network(USN) system composed of man-made sensors. The telemetry system used for communicating to access informations between nature and human-beings monitors and estimates the status of infrastructure, utilities and natural environments to prevent hidden disasters, improving quality of life and productivity in multi-directional views. That would be the reason of USN subsistence. This paper will be a review on how to build long-term USN system. Therefore, this paper focuses on reviewing the sensor interface and the sensor network interface and its significance as the foundation stone for varying USN service profiles and showing its development example, and finally proposing a few of things to set up future-oriented USN open system.