• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.150.3-150
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• 2001

Requirements for Distributed Monitoring and Control Networks (DMCN) differ greatly from those of typical data networks. Specifically, any DMCN technology which employs a fieldbus protocol is different from If network protocol TCP/IP. In general, one needs to integrate fieldbus protocol and TCP/IP to realize DMCN over IP network or internet Interoperability between devices and equipments is essential to enhance the quality and the performance of predictive maintenance (PM). This paper suggests a basic framework for LonWorks-based DMCN over IP network and a method to guarantee interoperability between devices and equipments.

• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.242-252
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• 2002

When a Mobile IP handoff occurs, the packets in flight can be lost because they are tunneled based on out-of-date location information. In this parer, we propose an enhanced handoff protocol that achieves no packet loss during Mobile IP handoff over a wireless LAN. Our handoff protocol predicts the next foreign agent that a mobile host is to visit by using: the information from the data link layer of wireless LAN. After that, when a Mobile IP handoff occult, the current foreign agent forwards the packets destined to a mobile host to the predicted foreign agent which buffers them. This eliminates packet loss and reduces the packet forwarding delay. Our handoff protocol is simulated using the Network Simulator-2 (ns-2) and shows the substantial performance enhancement of TCP with much less overhead up to 6.2 times compared to standard Mobile IP.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.29-35
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• 2024

TCP is considered as one of the major candidate transport protocols even for constrained IoT networks..In our previous work, we investigated the congestion control mechanism of the uIP TCP. Since the uIP TCP sets the window size to one segment by default, managing the retransmission timer is the primary approach to congestion control. However, the original uIP TCP sets the retransmission timer based on the fixed RTO, it performs poorly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe. In our previous work, we proposed a TCP retransmission timer adjustment scheme for uIP TCP which adopts the notion of weak RTT estimation of CoCoA, exponential backoffs with variable limits, and dithering. Although our previous work showed that the proposed retransmission timer adjustment scheme can improve performance, we observe that the scheme often causes a node to set the retransmission timer for an excessively too long time period. In this work, we show that slightly modifying the dithering mechanism of the previous scheme is effective for improving TCP fairness.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.463-465
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• 1999

인터넷으로 연결된 모든 장치는 각 나라마다 정해진 권위기관으로부터 고유한 IP 주소를 할당 받게 되는데, 현재 Internet Network Center(Inter NIC)라는 조직에서 이를 전체적으로 관장하고 있다. 최근 인터넷 사용이 급속히 확산되면서 인터넷을 이용하는 모든 장치에 고유 IP 주소를 할당하게 될 경우 고유 주소 체계의 사용 가능한 IP 주소 고갈이라는 문제에 직면하게 되었다. 그러나 이러한 문제는 내부 근거리 통신망(LAN)과 인터넷 상에 IP 주소를 변환시켜 주는 역할을 하는 네트워크 주소 변환(NAT: Network Address Translation) 기능을 이용하여 보완할 수 있다. 본 연구에서는 사설망 사용자의 인터넷 접속을 제공하는 것으로 기존 라우터에 NAT 기능을 적용하여 라우터가 보유한 공인 주소를 각 사용자가 공유하여 인터넷 접속을 제공하는 것으로 기존 라우터에 NAT 기능을 적용하여 라우터가 보유한 공인 주소를 각 사용자가 공유하여 인터넷 접속을 시도하는 것으로 사설망의 IP주소를 공인된 인터넷 주소로 변환시켜 외부로 전송하므로써 가능하다. 또한, 주소 변환 과정으로 사설망에서 사용하는 IP주소가 NAT 기능으로 IP주소가 변경되어 외부 침입자가 사설망의 존재를 알 수 없어 침입을 막는 간접적인 방화벽 기능도 수행한다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8S
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• pp.2679-2687
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• 2000

위성 ATM 망에서 TCP/IP 기반의 응용 서비스를 제공하기 위해서는 위성의 긴 전송지연과 이성 채널의 버스트 오류 특성에 따른 정확한 전송 성능의 영향과 분석이 요구되며, 아울러 성능 목표치가 제시되어야 한다. 본 논문은 2Mbps급 KOREASAT위성을 이용한 위성망과 지상망이 상호 연동된 실제 위성/지상 ATM LANE(LAN Emulation)을 구현하고, 위성 채널의 Eb/No와 TCP 소켓 버퍼 크기, 그리고 전송 메시지 크기를 바꾸어 가면서 그때의 TCP/IP 트래픽과 FTP의 전송성능을 비교 분석하였다. 아울러 IPoA(IP over ATM)기반의 영상회의 서비스에 대한 전송 품질 및 메시지 전달 특성 등을 분석하였다. 연구결과 TCP 소켓 버퍼 크기가 증가할 때 TCP의 전체 성능이 증가함을 알 수 있으나 제한된 최대 윈도우 크기 64kbytes와 위성채널의 오류 특성으로 인해 실제 최대 전송속도는 이론상의 목표치를 달성하지 못함을 보여 주었다. 또한 2Mbps 위성링크에서 Eb/No가 6dB 이하에서는 실제적으로 제공할 수 있는 최대 전송성능의 50%이하로 떨어져 TCP/IP over ATM 서비스가 거의 불가능함을 보여주었다. FTP의 경우, 파일 크기가 작으면 최대 전송속도에 도달하기 전에 파일 전송이 완료되어 대역폭 이용의 효율성 측면에서 TCP/IP의 slow start 메케니즘이 적절하지 않음을 보여주었다. 이울러 IPoA영상회의 서비스에서도 Eb/No가 약 6.5dB 이하에서는 영상이 거의 정지되고, 메시지 전달시간도 ITU에서 권고하는 목표치를 훨씬 상회하여 서비스가 거의 불가능함을 보였다.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.113-124
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• 2009

With increasing multicore system, much effort has been put on the performance improvement of its application. Because multicore system has multiple processing devices in one system, its processing power increases compared to the single core system. However in many cases the advantages of multicore can not be exploited fully because the existing software and hardware were designed to be suitable for single core. When the existing software runs on multicore, its performance improvement is limited by the bottleneck of sharing resources and the inefficient use of cache memory on multicore. Therefore, according as the number of core increases, it doesn't show performance improvement and shows performance drop in the worst case. In this paper we propose a method of performance improvement of multicore system by applying Flow-Level Parallelism to the existing TCP/IP network application and operating system. The proposed method sets up the execution environment so that each core unit operates independently as much as possible in network application, TCP/IP stack on operating system, device driver, and network interface. Moreover it distributes network traffics to each core unit through L2 switch. The proposed method allows to minimize the sharing of application data, data structure, socket, device driver, and network interface between each core. Also it allows to minimize the competition among cores to take resources and increase the hit ratio of cache. We implemented the proposed methods with 8 core system and performed experiment. Experimental results show that network access speed and bandwidth increase linearly according to the number of core.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.477-486
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• 2010

This Study suggests security directions to reconstruct separate network of Smart Grid and information communication network as one communications system and implement Smart Grid integrated information communication network. In addition, it suggests prevention directions to prevent future cyber attacks by reorganizing network as the key three-stage network and separating TCP/IP four layers that consist of existing information communication network from Smart Grid. Moreover, it suggests the foundation for the study and the test by providing current problems of Smart Grid, weak points, and three security models. This study is meaningful to suggest development directions and situations as a technology of future-oriented electric industries, integrate attacks and preventions of TCP/IP Layers with Smart Grid, and seek for a new technology of Smart Grid and future tasks for Smart Grid information security.

• Journal of the Korea Society of Computer and Information
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• v.17 no.9
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• pp.103-112
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• 2012

Recently, the infrastructure to be connected to the internet is much provided, there is more and more need to connect electric or electronic products to the internet to monitor or control them remotely. However, most of the existing products lack the network interface, so it was very inconvenient to be connected to the internet. Therefore, this article designs and realizes the internet outlet allowing real-time scheduling that can control the power remotely on the internet by using the hardware TCP/IP processor. The realized product consumes low production cost because it can be realized by using the hardware TCP/IP processor and the 8-bit small microprocessor. In addition, the product can be used widely in both wired and wireless environments with a variety of user interface, including the dedicated control program which provides the environment configuration functions; embedded web service that enables the webpage to be saved on the external flash memory; Android smartphone application; motion recognition control environment that uses the OpenCV computer vision library, etc.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.848-854
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• 2009

Of the rapid development of modem civilization development is one of the IT industry. The Network is the root of the discrete industry. Most of the Protocol is used by LAN and the TCP / IP. Slowly in the railway operation of this Network is being applied. It also used to train and they are operated. The concept of the road, the Network TCP / IP using a non-Star structure of the Main Unit and the Bus Network is designed to structure consists of the Network. This structure is a simplified DATA. Data of complex operations is easy to feel the speed limit is. In addition, all devices must be independent to the operating system with the ability to manage the operation and stability in terms of exactly how the transmission of Data is gonna work pass. And transmission occurs in the middle of the Noise and the device is available to manage the power. Noise in the power of the railway to ensure the efficient transfer of Data is by blocking. Also, by presenting the entire system's operational safety should be guaranteed the safety of the railway.

• Annual Conference of KIPS
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• 2003.11b
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• pp.1277-1280
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• 2003

본 논문은 지니 네트웍 프로토콜을 TCP/IP 기반에서 IEEE 1394로 확장하여 IEEE 1394와 TCP/IP를 동시에 지원하는 홈 네트웍에서의 지니 룩업 서비스 구조 및 방법에 관한 것으로, IEEE 1394 프로토콜 기반 서비스와 TCP 기반 서비스 사이의 상호 연동을 제공할 수 있는 구조를 제공하기 위해 기존의 지니 시스템의 룩업 서비스를 확장하여 홈 엔터테인먼트 네트웍을 쉽게 구성할 수 있도록 한다. 즉, 본 논문에서는 자바 기반 네트웍 미들웨어 구조에 IEEE 1394 네트웍과 TCP/IP 네트웍간 채널링을 수행하는 SLCH를 구현하여 IEEE 1394와 TCP/IP 프로토콜을 모두 지원 가능하도록 함으로써, TCP/IP와 IEEE 1394 사이의 정보 교환을 위해 큐 메카니즘을 사용하여 IEEE 1394 기기도 지니 네트웍에 손쉽게 연결되도록 함으로서, 서로 다른 종류의 네트웍을 지원하는 클라이언트나 서비스 제공자사이의 서비스 이용이 가능하게 되는 이점이 있다.