• Convergence Security Journal
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• v.14 no.7
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• pp.17-22
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• 2014

Wireless Ad hoc Network is threatened from many types of attacks because of its open structure, dynamic topology and the absence of infrastructure. Attacks by malicious nodes inside the network destroy communication path and discard packet. The damage is quite large and detecting attacks are difficult. In this paper, we proposed attack detection technique using secure authentication infrastructure for efficient detection and prevention of internal attack nodes. Cluster structure is used in the proposed method so that each nodes act as a certificate authority and the public key is issued in cluster head through trust evaluation of nodes. Symmetric Key is shared for integrity of data between the nodes and the structure which adds authentication message to the RREQ packet is used. ns-2 simulator is used to evaluate performance of proposed method and excellent performance can be performed through the experiment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.19-26
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• 2014

The advent of smart phones brought adverse effect between devices recently. For example, adverse effects of info-communication with advent of computer. Also, hacking threat aiming cyber space that is getting more advanced is spreading in terms of range and danger, so that it reaches the level that the nation has to concern. In this circumstance, crimes involving info-technology is now problem in society. As internet technology advances, it enlarges the range of hacker's threat to not only smart phones, but ships, aircrafts, buildings, and cars. It could be seen as social threat of between human and human, between machine and machine, and between human and machine. This study discuss these problems.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.740-754
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• 2015

This paper focuses on the reverse blocking busbar protection scheme with aim to improve the speed of its operation and at the same time to increase operational reliability, flexibility and stability of the protection during external and internal faults by implementation of the extended functionality provided by the IEC61850 standard-based protective Intelligent Electronic Devices (IEDs). The practical implementation of the scheme by the use of IEC 61850 standard communication protocol is investigated. The proposed scheme is designed for a radial type of a distribution network and is modeled and simulated in the DigSILENT software environment for various faults on the busbar and its outgoing feeders. A laboratory test bench is built using three ABB IEDs 670 series that are compliant with the IEC 61850 standard, CMC 356 Omicron test injection device, PC, MOXA switch, and a DC power supplier. Two types of the reverse blocking signals between the IEDs in the test bench are considered: hard wired and Ethernet communication by using IEC 61850 standard GOOSE messages. Comparative experimental study of the operational trip response speeds of the two implementations for various traffic conditions of the communication network shows that the performance of the protection scheme for the case of Ethernet IEC 61850 standard-based communication is better.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.627-633
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• 2008

In the case of traffic accidents, the broadcasting methods used in the mobile ad hoc network (MANET) cannot applied to transmit reliable message since moving high-speed in vehicular ad hoc networks (VANET) environments. In this paper, in order to guarantee transmitting reliable messages, we propose a collision avoidance method based-on directional antenna in VANET. In order to reduce interference from omni-broadcasting and to avoid hidden node problem from moving high-speed, we employed a forward-handed and backward directional antenna. The authors simulated the proposed method based on directional antenna and showed that the proposed method has been improved in respect to network utilization compared to existing VANET protocols.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.436-444
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• 2009

As the interest in sensor networks has been increased recently, researches have been performed in many areas using sensor networks. In this paper, we propose and implement a lecture room control system based on a sensor network. It is possible to give an efficient lecture by collecting lecturers' lecture history information through the sensor network and controlling a PC, a beam projector, lights, etc. in a lecture room appropriately using the information. We construct a sensor network and perform experiments so that the proposed lecture room control system performs efficiently. Through the experiments, we obtained the optimal message generation period of the sensor node in a lecture room and the optimal number of sensor nodes deployed in a lecture room to communicate without any trouble between sensor nodes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.182-189
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• 2010

This paper defines the quorum-based fault-tolerant mutual exclusion problem in a message-passing asynchronous system and determines a failure detector to solve the problem. This failure detector, which we call the modal failure detector star, and which we denote by $M^*$, is strictly weaker than the perfect failure detector P but strictly stronger than the eventually perfect failure detector ◇P. The paper shows that at any environment, the problem is solvable with $M^*$.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.1
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• pp.7-26
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• 1998

In this study, an ILL request system was implemented using Z39.50 item order extended service. ILL requests in this system are initiated by users through a gateway acting as a Z39.50 origin for searching remote catalog databases. When users initiate a request while searching OPACs of other libraries, an extended service request PDU for item order is first sent to the home library which subsequently generates an ILL protocol message to be sent to the target library. This approach enables users to request an item online while searching. and at the same time allows the home library to retain control over the ILL transaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1640-1645
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• 2010

There exists an inconvenience that players of each instrument pass musical score in orchestra recital. In this paper, we implement the electronic musical score transmitting system that possible to hand sheet music automatically, using Mini - ITX and LCD Panel. We made them unite with a sheet music pair, and it was made and a message and data transmission were embodied using reliable TCP/IP socket communication. In this paper, the client hands sheet music automatic, and server implemented the manual function to manage each clients individually. Because one band can be managed by one Access file all together, it is easy to manage each band. Along with this, this system selects TCP/IP as the reliable transfer protocol that protect loss and errors.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.2
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• pp.79-85
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• 2020

IIoT stands for Industrial Internet of Things used in manufacturing, healthcare, and transportation in networked smart factories. Recently, IIoT's environment requires an automated control system through intelligent cognition to improve efficiency. In particular, IIoT can be applied to automatic calibration of production equipment for improved management in industrial environments. Such automation systems require a wireless network for transmitting industrial data. Self-calibration systems in laser transmission paths using wireless networks can save resources and improve production quality by real-time monitoring and remote control of laser transmission path. In this paper, we propose a wireless networked system for self-calibration of laser equipment that requires a laser transmission path, and we show the results of the prototype evaluation. The self-calibration system of laser equipment measures the coordinates of the laser points with sensors and sends them to the host using the proposed application protocol. We propose a wireless network service for the wired motor controller to align the laser coordinates. Using this wireless network, the host controls the motor by sending a control command of the motor controller in an HTTP message based on the received coordinate values. Finally, we build a prototype system of the proposed design to verify the detection performance and analyze the network performance.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.373-380
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• 1997

In this paper, we describe the intrabed network in a patient monitoring system we developed The intrabed network handles data communication between the main unit of a bedside patient monitor and parameter modules plugged in it. We designed the intrabed network based on RS-485 and HDLC protocol with 1 Mbps data rate. Message exchanges are implemented based on three data structures of packet frame. and stream. We present the specification and the performance of the data communication network for the developed patient monitor.