• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.194-199
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• 2007

In this paper, a slotted CDMA_ALOHA protocol with hybrid ARQ is proposed for the wireless CDMA communication networks. The proposed protocol combines the characteristics of the slotted ALOHA, CDMA, and the hybrid ARQ, in order to increase the throughput by reducing the number of retransmissions when the channel experiences heavy traffic. The main feature of the proposed protocol is the utilization of the forward error correction capability to correct errors that appear after the CDMA dispreading of the packets. The base station does not need to ask so often for retransmission of erroneous packets. It will request for retransmission only when the FEC capability is exceeded. The performance of the proposed protocol is analyzed by considering the packet collision probability as well as the bit error probability. The numerical results show that the system throughput is closely related to the bit error rate of the wireless link and the FEC coding rate.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.101-110
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• 2011

A smart grid networks delivers electricity from suppliers to consumers using digital technology with two-way communications to control appliances at consumers' homes to save energy, reduce cost and increase reliability and transparency. Security is critically important for smart grid networks that are usually used for the electric power network and IT environments that are opened to attacks, such as, eavesdroping, replay attacks of abnormal messages, forgery of the messages to name a few. ZigBee has emerged as a strong contender for smart grid networks. ZigBee is used for low data rate and low power wireless network applications. To deploy smart grid networks, the collected information requires protection from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. However, the ZigBee protocol has some security weaknesses. In this paper, these weaknesses are discussed and a method to improve security aspect of the ZigBee protocol is presented along with a comparison of the message complexity of the proposed security protocol with that of the current ZigBee protocol.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.920-925
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• 2010

A home network system is made up of home devices and wire and wireless network can not only be the subject of cyber attack from a variety factors of threatening, but also have security weakness in cases of hacking, vicious code, worm virus, DoS attack, tapping of communication network, and more. As a result, a variety of problems such as abuse of private life, and exposure and stealing of personal information arose. Therefore, the necessity for a security protocol to protect user asset and personal information within a home network is gradually increasing. Thus, this dissertation designs and suggests a home network security protocol using user authentication and approach-control technology to prevent the threat by unauthorized users towards personal information and user asset in advance by providing the gradual authority to corresponding devices based on authorized information, after authorizing the users with a Public Key Certificate.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.60-60
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• 2000

CAN(Controller Area Network) is a serial communication protocol which specifies very low cost and high performance. It is widely used in rea1-time control applications such as automobiles, aircraft, and automated factories. The main application fields are industrial control systems and embedded network. In this paper, the CAN monitoring system is proposed and implemented. Also its performance is tested in the mobile robot which is integrated by CAN and its performance lot receipt failure rate is evaluated. This can be used to analyze the performance of the network. It can tie also used to manage and monitor the network.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.43-48
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• 2004

RTP that is proposed supplement of real-time services on internet environment, as Real-time Transport Protocol, is the protocol that for the purpose of sending data of stream type. RTP and RTCP(Real-time Transport Control Protocol) basically work at the same time, RTCP serves with state information of network at present. RTP has important properties of a transport protocol that runs on end-to-end systems and provides demultiplexing. It also offer reliability and protocol-defined flow／congestion control that transport protocol like TCP can not provides. In this paper, we look around concept and construction of Differentiated sen1ice tint run on RTP and by setting parameters of packet transfer method be used CBQ(Class-Based Queuing) for packet transfer on Differentiated service, each service queue controls properly through packet scheduling method, such as WRR(Weighted Round Robin) and PRR(Packet-by-packet Round Robin) all service classes do not experience the starvation and confirm the performance through computer simulation to achieve fairly scheduling.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.1
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• pp.23-28
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• 2010

The automotive industry tries to provide infotainment systems to emerging automobiles. Since the infotainment systems require various peripheral devices and network connectivity, legacy operating systems such as Linux and Windows can be much preferred due to its plentiful device drivers and multimedia applications while the operating systems following OSEK standard are used for automotive electronic control units. Thus it is highly desired that the system software supporting infotainment applications can be portable over different legacy operating systems providing unified programming interfaces. The majority of legacy operating systems support POSIX interfaces for application development. MOST is an automotive network standard for infotainment systems. Network Service defines the protocol stacks for MOST control data, which is essential to implement infotainment applications over MOST. In this paper, we suggest a POSIX-based Network Service so that we can utilize legacy device drivers and applications for automotive infotainment systems. We measure the performance of the POSIX-based Network Service and show that its overhead is not significant.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.5
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• pp.859-870
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• 2020

The MQTT-SN (Message Queuing Telemetry Transport-Sensor Network) protocol is a message transmission protocol used in a sensor-based Internet of Things (IoT) environment. This MQTT-SN protocol is a publish-subscribe model with a broker in the middle of message transmission, and each IoT device sends and receives messages through an intermediary when delivering messages. However, the MQTT-SN protocol does not provide security-related functions such as message security, mutual authentication, access control, and broker security. Accordingly, various security problems have recently occurred, and a situation in which security is required has emerged. In this paper, we review the security requirements of MQTT-SN once again, and propose a modified protocol that improves security while satisfying the constraints in the environment where the resource of IoT to which this protocol is applied is limited. Unlike the existing protocol, the security field and authentication server have been added to satisfy the security requirements. In addition, the proposed protocol is actually implemented and tested, and the proposed protocol is evaluated for practical use in terms of energy consumption.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.362-364
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• 1992

In this paper, the development of a fiber optic network for an integrated digital protection relay system is described. The structure of the developed network is determined to loosen the optic requirements and to have good extensibility while providing sufficient functions for protection and control for substations. The network has a hierarchical structure with two levels. The upper level handles data for monitoring and control of the system with star topology. The lower level manages the real time data for bus protection with one-to-one connections. Communication flows of each level are described. The HDLC is employed as the network protocol.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.491-496
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• 2009

In this paper, we propose USN Protocol of Room Control with high efficiency and new routing techniques. I establish a network of cluster hierarchy structure under bases standard for IEEE 802.15.4 and another networks to manage each room use a control packet transmitted and The proposed protocol does not perform BroadCast over a network and transmits a packet to same layer to the destination and then passes the packet after doing searches. If a destination to be transmitted cannot be looked up, the protocol transmits AODV routing packet so that not only traffic load of a wireless network is decreased, but also efficient routing path can be obtained.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.549-557
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• 2017

ICMP(Internet Control Message Protocol) is a main protocol in TCP/IP protocol stack. ICMP compensates the disadvantages of the IP that does not support error reporting. If any transmission problem occurred, a router or receiving host sends ICMP message containing the error cause to sending host. However, in this process, an attacker sends a fake ICMP messages to the host so that the communication can be terminated abnormally. An attacker host can paralyzes system of victim host by sending a large number of messages to the victim host at a high rate of speed. To solve this problem, we have designed and implemented outbound traffic controller that prevents various ICMP attacks. By preventing the transmission of attack messages in different ways according to each case, various network attacks can be prevented. In addition, unnecessary network traffic can be filtered before transmitted.