• Proceedings of the IEEK Conference
• /
• 2003.07a
• /
• pp.157-160
• /
• 2003

ODMRP is protocol that support multicast and unicast in Ad-hoc network. When some one node must transmit data by unicast way in this ODMRP, must pass through periodic flooding process to find a path and overhead happens thereby. Our scheme stores the found path into the table in a unicast mode and, when the node sends data, it refers to the DR FG table so that reduces the traffic caused by control packets(JOIN QUERY, JOIN REPLY) of a receiver node, while source/destination nodes flood periodic control packets to look for a path in ODMRP. We present that our scheme is much more improved on the time of looking for a path than existing ODMRP methods by means of the simulation.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2542-2544
• /
• 2000

In this paper, CAN(Controller Area Network)is used to solve the wire harness problem in the outside mirror of automobile which has a lot of functions in narrow space. If the number of wires is reduced, it has benefits of lower product cost and maintenance. CAN was originally developed by the German company Robert Bosch for use in the car industry to provide a cost-effective communications bus for in car electronics and as alternative to expensive and cumbersome wiring looms. CAN controller is a serial communication protocol which efficiently supports distributed real-time control with a very high level of security. The communication between master CAN controller and slave CAN controller is realized and controller's performance is tested by experiment.

• Journal of Communications and Networks
• /
• v.17 no.2
• /
• pp.203-209
• /
• 2015

Although mobile applications are an essential characteristic of wireless sensor networks, most existing media access control (MAC) protocols focus primarily on static networks. In these protocols, fixed periodic neighbor discovery and schedule updating are used to connect and synchronize neighbors to provide successful data transmission; however, they cannot adapt to mobile speed variation and degrade the network performance dramatically. In this paper, we propose a mobile-supporting mechanism for MAC protocols, in which the decision to update the neighbors of a mobile node is made adaptively according to the mobile speed. Analysis and simulation results demonstrate that the mechanism efficiently avoids the disconnection of amobile node from its neighbors and achieves a better performance as compared with fixed periodic neighbor discovery.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.397-403
• /
• 2004

The controller area network(CAN) was originally developed to support cheap and rather simple automative applications, However, because of the its performance and low cost, it is also being considered in automated manufacturing and process control environments to interconnect intelligent devices, such as modem sensors and actuators. This paper presents a new application technology of the developed CAN control modules for the automated doors in building automation system. Key pad and RF methods are used to open and close the automated door by the slave CAN module with CAN protocol. BAS application technology of CAN field bus modules is also presented firstly in our nation.

• Journal of KIISE:Computing Practices and Letters
• /
• v.5 no.3
• /
• pp.336-343
• /
• 1999

본 논문은 지능형 정보 제공 시스템(IP : Intelligent Peripheral)의 주요 소프트웨어 블록 중 하나인 자원 서비스 제어부의 구현 방법을 설명한 것이다. 본 연구의 자원 서비스 제어부는 ITU-T INCS-1에 정의된 특수자원 기능실체(SRF : Specialized Resource Function)의 상태모델을 실현시킨 소프트웨어 블록으로서 IP 하드웨어 구성요소의 하나인 특수자원교환기(SRS : Specialized Resource Switch) 의 CROS(Concurrent Realtime perating System)상에서 CHILL(CCITT High Level Programming Language)로 구현되었으며, 지능망서비스제어시스템(SCP : Service Control Point)이 보낸 지능망 응용프로토콜(INAP : Intelligent Network Application Protocol)오퍼레이션을 분석하여 IP가 보유한 자원 구동에 필요한 모든 절차를 제어한다. 또한 동시에 수신된 INAP오퍼레이션들에 대한 순서제어기능, 통계데이타 제공기능, 사용자 상호작용 종료 기능등을 제공한다. 제안된 구현기술은 자원서비스 제어부가 실제 자원을 동작시키는 IP 하드웨어 구성요소인 특수자원유닛(SRU : Specialized Resource Unit)을 클라이언트/서버형태로 유지하여 이들 자원의 상태를 관리함으로써 IP의 확장성을 보잔하여, 교환기 실시간 데이터베이스를 이용하여 IP가 생성하는 수만여개의 메시지를 효율적으로 관리할 수있다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.6B
• /
• pp.553-562
• /
• 2003

Supporting QoS (Quality of Service) for the multimedia applications becomes an important issue as the demand of multimedia applications increases. Thus, it is necessary for the application layer to have an efficient congestion control algorithm, which can support the multimedia applications' QoS requirements. In this paper, we propose a new application layer congestion control algorithm, called RRC-OTT (Receiver-based Rate Control with One-way Trip Time). RRC-OTT algorithm differs from the previously proposed algorithms in that the receiver takes the responsibility of the network congestion control. Thus, RRC-OTT algorithm can not only precisely estimate the network congestion using OTT (one-way Trip Time), but reduce the work load from the sender (e.g., the web server). Our simulation study shows that RRC-OTT algorithm can maintain the comparable link utilization to the previously proposed algorithms and keep the packet jitter low, which thus can help enhance the quality of multimedia applications.

• Journal of Korean Society of Water and Wastewater
• /
• v.32 no.4
• /
• pp.309-315
• /
• 2018

Currently, the commercialization of the $5^{th}$ Generation (5G) service is becoming more prevalent in domestic communication network technology. This has reduced communication delay time and enabled large-capacity data transmission and video streaming services in real-time. In order to keep pace with these developments, K-water has introduced a smart process control system in water purification plants to monitor the status of the water purification process. However, since wireless networks are based on the public Long Term Evolution (LTE) network, communication delay time remains high, and high-resolution video services are limited. This is because communication networks still have a closed structure due to expense and security issues. Therefore, with 5G in its current form, it is very difficult to accommodate future services without improving the infrastructure of its communication networks. In recognition of these problems, this study implemented the authentication and management function of wireless networks on a wired network management system in the K-water Bansong water purification plant. The results confirmed that wired Local Area Network (LAN) services give a higher security performance than an expensive commercial wireless LAN system. This was achieved by using an Internet Protocol (IP) address management system of wired networks and the packet filtering function of the Layer2 (L2) switch. This study also confirmed that it is possible to create a wireless LAN service that is 3.7 times faster than the existing LTE communication network.

• Journal of KIISE:Information Networking
• /
• v.35 no.6
• /
• pp.529-537
• /
• 2008

AODV routing protocol is intended for use by mobile' nodes in an ad-hoc network. In AODV nodes create routes on an on-demand basis. As the degree of node mobility becomes high, however, the number of the control packets, RREQ and RREP messages, have increased so rapidly. The unexpected increases in the number of the control packets cause the destination node to decrease the packet receiving rate and also to increase the overall energy consumption of such a network. In this paper, we propose a novel method of adaptively controlling the occurrences of such RREQ messages based on AIAD (additive increase additive decrease) under a consideration of the current network status. We have tested our proposed method with the conventional AODV and the method using timestamp based on the three performance metrics, i.e.. how long does node moves, node velocity, and node density, to compare their performance.

• Journal of KIISE:Information Networking
• /
• v.34 no.3
• /
• pp.143-155
• /
• 2007

In video streaming applications over the Internet, TCP-friendly rate control schemes are useful for improving network stability and inter-protocol fairness. However it does not always guarantee a smooth quality for video streaming. To simultaneously satisfy both the network and application requirements, video streaming applications should be quality-adaptive. In this paper, we propose a new quality adaptation mechanism to adjust the quality of congestion controlled video stream by controlling the frame rate. Based on the current network condition, it controls the frame rate and sending rate of video stream. Through the simulation, we prove that our adaptation mechanism appropriately adjusts the quality of video stream while improving network stability.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.5B
• /
• pp.413-420
• /
• 2006

HMIPv6 is designed to reduce the signaling load to external network and improve handover speed of MN by including Mobility Anchor Point(MAP) in local handover. However in this case of macro handover, it's just used pervious MIPv6 handover algorithm. So, it occurs packet loss and transmission delay problem. In this paper, we propose the mechanism applying the HMIPv6 for Fast Handover to choose suitable to the condition buffering handover. The condition for the selection is result distance measurement between MN and CN, between MN and NAR. Furthermore, using F-SNOOP protocol, it is possible to improve wireless network performance. Wireless network has high Bit Error Rate(BER) characteristic because of path loss, fading, noise and interference. TCP regards such errors as congestion and starts congestion control. This congestion control makes packet transmission rate low. However, F-SNOOP improves TCP performance based on SNOOP and Freeze TCP that use Zero Window Advertisement(ZWA) message when handoff occurs in wireless network.