• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.841-847
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• 2015

The WAVE(Wireless Access in Vehicular Environments) communication system supports wireless communication environments between vehicles. As the utilization of wireless communication has been increased, attack methods have been varied. There is a high risk on packet manipulations conducted by third party. In this paper, we have designed a secure communication protocol between CA and vehicles. Our designed protocol uses a ECIES(Elliptic Curve Integrated Encryption Scheme) for vehicle authentication and AES(Advanced Encryption Standard) algorithm for protecting packet integrity and confidentiality.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.69-72
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• 2011

플래시 메모리 기반의 저장 시스템은 빠른 접근 속도, 작고 가벼운 특성, 저전력 소모 등의 이유로 하드 디스크를 대체하는 저장 매체로 주목 받고 있다. 플래시 메모리는 하드 디스크와 다르게 읽기 쓰기 소거 연산이 필요하며 수혈 단위와 수혈 시간 이 비대칭적이다. 또한 제자리 갱신이 불가능하기 때문에 가장 느린 소거 동작을 선행하여 갱신 연산을 수행한다. 기존 호스트 시스템은 읽기 쓰기 연산 만을 수행하기 때문에 플래시 메모리를 바로 사용하기 위해서는 별도의 소프트웨어 중간 계층인 플래시 전환 계층이 필요하다. 그러나 디스크 기반의 B-트리를 플래시 전환 계층 위에서 인덱스로 사용하면 B-트리 특성상 제자리 갱신이 빈번하게 발생하기 때문에 성능 저하가 발생한다. 따라서 플래시 메모리 특성을 고려한 새로운 인덱스 구조가 필요하게 되었다. 플래시 메모리 전용의 인덱스 ${\mu}$-트리와 LSB-트리가 제안 되었지만, ${\mu}$-트리는 페이지 관리의 비효율성, LSB-트리는 임시 노드 관리 추가 비용의 문제점을 가지고 있다. 본 논문에서 ${\mu}$-트리와 LSB 트리의 문제점을 해결하기 위하여 지연 갱신을 이용한 B-트리를 제안한다. 제안하는 인덱스는 변경이 일어나는 노드를 메모리에 적재시켜 데이터 삽입 시 노드 갱신을 지연시키고 노드 분할 없이 데이터의 순차 삽입을 처리하여 검색 및 쓰기 성능을 향상시킨다. 본 논문에서는 관련 연구인 ${\mu}$-트리와 LSB-트리를 수식을 통하여 제안하는 인덱스 구조의 우수성을 보인다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.784-791
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• 2005

To provide VoD Service on the Internet VoD server is required to have a large amount of system resource and network bandwidth. Therefore, overlay Multicast schemes are considered as suitable alternatives but they also have some drawbacks to support on-demand media services. In this paper, we propose an overlay multicast based on-demand media service scheme which could exploit server's system resource and its network bandwidth efficiently. Proposed scheme uses shared buffer of clients involving the relay of traffic and Patching while it gives no restrictions to this scheme compared with unicast. Our simulation results show that proposed scheme can support more user than unicast and improve the network performance at the same time.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.865-870
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• 2001

For pneumatic system control, we need a data transmission system with high speed and high reliability or information interchange between main computer and solenoid valves and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition we developed a communication protocol for construction of RS-485 based multidrop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is possible up to 1,000m without using repeater. In addition, the system developed in this research is proved to be used easily for extension of a communication network because of its module structure.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.138-147
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• 2003

There are some problems of current internet protocols to support the mobility of terminal in wireless environments. The mobile IP has come out to solve these problems, but there exists some problems like triangle routing, the need of each host's home address and the management of tunneling. Also. real-time multimedia traffics require fast hand-off, low latency and the utilization ratio of high bandwidth. SIP can support the mobility of wireless terminal and is widely accepted as the protocol which can support multimedia service and call setup in next generation network. In this paper, the framework of SIP system will be designed and implemented to support the mobility of wireless terminal by using JAIN API which follow the standards of next generation network and this system matches the standards of next generation network.

• Journal of Korea Multimedia Society
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• v.3 no.4
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• pp.424-432
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• 2000

In this paper, we propose a new signaling method and circuits for interface between the host and LCD (Liquid Crystal Display) controller in the LCD system. The proposed circuits are allowed to transmit two data signals through modified-LVDS circuits and can reduce the operating frequency to a half. Then, we can solve EMI(Electro Magnetic Interference) problem and the power consumption by using differential signaling method. We have compared and analyzed the proposed method and the conventional methods in the power consumption and data rate. In addition, the proposed methods reduce hardware complexity significantly.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.397-408
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• 2017

As mobile traffic increases rapidly, DMM (Distributed Mobility Management) has been proposed as a mobility management technology for seamless communication of mobile devices as mobile traffic increases rapidly. the DMM distributes mobility management from the core network to the edge network, enabling stable binding updates with low latency. However, the DMM still have network delay and security problems for sessions. In this paper, we point out the problems existing in the DMM and propose a new protocol in which the MN (Mobile Node) directly participates in authentication and mutual authentication is correctly performed to solve this problem. We demonstrate not only security improvements but also performance improvements with performance analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.3
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• pp.236-240
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• 2004

We have implemented image monitoring system on PXA255 processor based embedded board that is ported QT/Embedded 2.3.7 version. User is able to monitor camera's capture image for widely separated host PC at client PXA255 board target board by ethernet communication method. And we designed PCI interface card that control motor for camera's Pan & Tilt. Bitmap format's images of $320\times{240}$ size are displayed on PXA255 board's TFT-LCD and User is able to monitor wanted position's image by touch screen input method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1824-1837
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• 1994

Broadband ISDN will support advanced communication services such as multimedia conference, VOD and electronic news service. Because many of these advanced services require multimedia data delivery, future communication networks must have flexible and efficient multiparty communications capabilities. In this paper we propose a new multicasting method which uses packer filtering capabilities both in a physical network and in a logical network layers. This new scheme has potential to reduce the transmission and packet processing overheads of multicast communications. For the new multicasting method, we develop a group matching algorithm which finds a suitable set of groups that covers multiple target hosts. We show the application of the multicasting method and the group matching algorithm with two simple examoles.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.119-127
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• 1998

In this paper, the design of a VLSI-based multilayer neural network is presented, which can be used as a dedicated hardware for character-type segmentation and character-element recogniti on consuming large processing time in conventional software-based Hangul printed-character recognition systems. Also the architecture and its design of a neural coprocessor interfacing the neural network with a host computcr and controlling thc neural network are presented. The architecture, behavior, and performance of the proposed neural coprocessor are justified using VHDL modeling and simulation. Experimental results show the successful rates of character-type segmentation and character-element recognition is competitive to those of software-based Hangul printed-character recognition systems with retaining high-speed.