• The Journal of the Korea Contents Association
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• v.8 no.5
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• pp.19-28
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• 2008

In this paper, we implemented an intelligent home service robot system which alerts users to danger by wireless internet platforms for interoperability(WIPI) of a cellular phone. This paper discusses the three parts of the system: robot, middleware and mobile system. First, the robot consists of a gas sensor, a fire detector, ultrasonic sensors, motors, a camera and a Bluetooth module. The robot perceives various danger circumstances. Second, the middleware connects the robot and the mobile system. It monitors the robot and sends emergency notification SMS message to the user's cellular phone if in danger. Third, the mobile system sends commands which control the robot using TCP/IP protocol. The proposed scheme is to control the sensors of the robot part through Atmega 128 processor, and the robot and middleware parts will be installed in the household, and will be controled by mobile part from the outside.

• Journal of Information Technology Services
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• v.7 no.2
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• pp.1-12
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• 2008

The development of IT and explosively growing number of Internet users are rapidly spreading and developing e-commerce, while creating diverse on-line transaction methods such as a negotiation, a reverse auction, and a bid. Among these transaction methods, the transactions by means of a negotiation are being made for goods that have no posted price. In particular, the transactions by means of a negotiation are expected to be widely used in the B2B. In order to determine their transportation costs, shippers usually make negotiations with many transporters and logistics companies. And before long, these negotiations are expected to be made on an on-line automated negotiation system. Because of this, this study has tried to develop an automated negotiation methodology that is absolutely necessary for an on-line automated negotiation. This study has estimated and selected the evaluation functions for multi-lateral negotiators' proposals, thus developing an automated negotiation methodology. As a result of this study, a new direction for an automated negotiation has been suggested. Also we expect that this study will be widely used in the automated negotiation of diverse fields.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.723-731
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• 2005

Wide spread deployment of infrastructure WLANs has made Wi Fi an integral part of today's Internet access technology. Despite its crucial role in affecting end to end performance, past research has focused on MAC protocol enhancement, analysis and simulation based performance evaluation without sufficient consideration for modeling inaccuracies stemming from inter layer dependencies, including physical layer diversity, that significantly impact performance. We take a fresh look at IEEE 802.11 WLANs, and using experiment, simulation, and analysis demonstrate its surprisingly agile performance traits. Contention based MAC throughput degrades gracefully under congested conditions, enabled by physical layer channel diversity that reduces the effective level of MAC contention. In contrast, fairness and jitter significantly degrade at a critical offered load. This duality obviates the need for link layer flow control for throughput improvement but necessitates traffic control for fairness and QoS. We use experimentation and simulation in a complementary fashion, pointing out performance characteristics where they agree and differ.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.654-662
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• 2002

As the Internet technology becomes a major information infrastructure, an emerging problem is the tremendous increase of malicious computer intrusions. The present Intrusion Detection System (IDS) serves a useful purpose for detecting such intrusions, but the current situation requires more active response mechanism other than simple detection. This paper describes a multi-agent based tracing system against the intruders when the system is attacked. The focus of the study lies on the secure communication mechanism for the agent message communication. We have extended parameters on the KQML protocol, and apt)lied the public key encryption approach, The limitation might be the requirements of two-way authentication for every communication through the broker agent. This model ma)r not improve the efficiency, but it provides a concrete secure communication. Also this is one important factor to protect the agent and the tracing server during the tracing process.

• Journal of Information Management
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• v.38 no.1
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• pp.141-160
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• 2007

Many contents produced and provided as development of information technology on the internet. Especially discussion that collecting and storing of digital information resources, is expanded as growing dependence on academic information of research workers. Open Access is a new paradigm of information distribution that is opposite concept of high price distribution academic information. It is an OAI system that is intended to collect and automate open access data in good order. This paper constructs stOAI based on OAI that is a science and technology information providing system. This system provides international academic journal free of charge that collect and store through OAI protocol in OA(Open Access) of yesKISTI(science and technology information portal service). Also, It provides automate and centralize science technology information, that KISTI has, to external institution as a standard type.

• Journal of Broadcast Engineering
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• v.22 no.1
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• pp.107-117
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• 2017

Recently, IoT applications are being deployed in Smart TVs, and these IoT applications are using smart TVs as application platforms rather than broadcast platforms. With the advent of Hybrid broadcast technologies, now it becomes available to develop IoT applications which are coupled to the broadcast information. However, the existing IoT services are not suitable for Hybrid broadcast application since they are built on cloud and require various protocol implementations. In this paper, a Fog Computing-based architecture for hybrid broadcast application is proposed. Instead of accessing IoT services from hybrid broadcast app directly, the proposed architecture places Fog Applet Server between them and distribute loads of hybrid broadcast app to the Fog Applet. The proposed architecture is implemented as a service to control IoT device with hybrid application.

• Convergence Security Journal
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• v.13 no.2
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• pp.155-163
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• 2013

Connection hijacking attack using the vulnerability of the TCP protocol to redirect TCP stream goes through your machine actively (Active Attack). The SKEY such as one-time password protection mechanisms that are provided by a ticket-based authentication system such as Kerberos or redirection, the attacker can bypass.Someone TCP connection if you have access on TCP packet sniffer or packet generator is very vulnerable. Sniffer to defend against attacks such as one-time passwords and token-based authentication and user identification scheme has been used. Active protection, but these methods does not sign or encrypt the data stream from sniffing passwords over insecure networks, they are still vulnerable from attacks. For many people, an active attack is very difficult and so I think the threat is low, but here to help break the illusion successful intrusion on the UNIX host, a very aggressive attack is presented. The tools available on the Internet that attempt to exploit this vulnerability, known as the recent theoretical measures is required. In this paper, we propose analysis techniques on a wireless network intruder detection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4A
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• pp.377-384
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• 2006

According to fast VoIP technology development, more and more companies change voice network into IP based network among branch offices. IP PBX, which is deployed up to now, composed of IP phone and VoIP Gateway. Every telphone has replaced with If phone which support VoIP and VoIP gateway is installed in PBTN connection point to relay voice data. It can reduce the communication expense of International call, long distance call and call between a headquater and a trance because it uses internet line. In this paper, IP PBX is implemented that can distribute call using PBX network only usig personal terminal without Proxy Server. Depending on Role, terminal can be registered Master, Server and Client and it is verified in terms of performance and validation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.398-407
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• 2010

Due to increase of user requirement for various traffics and the advance of network technology, each distinct network has converge into FMC(Fixed Mobile Convergence) networks. However, we need to research the performance analysis of VoIP(Voice over Internet Protocol) in the FMC network to provide QoE for the voice user of FMC network. Therefore, this paper introduces the scenario which is the situation of voice quality degradation when a user uses VoIP to communicate with other users in the FMC network. Especially, this paper presents scenario in terms of the component of the network and finds the improvement point of voice quality. In the simulation results, three improvement points of voice quality are found as following: voice quality degradation by packet loss in the physical layer of the HSDPA network, by utilizing GGSN without QoS parameter mapping mechanism which is gateway between 3GPP and IP backbone, and by using non-QoS AP in the WLAN network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.889-891
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• 2017

Visible light communication technology, which is a communication using LED lighting, is defined by IEEE 802.15.7 WG and active research is under way. Visible light communication is advantageous not only to avoid interference with existing RF communication but also to provide location based service through accurate positioning by utilizing LOS (Line of Sight) characteristic. Therefore, it is very easy and efficient to locate and track the user's location. In this paper, we implemented a visible light communication transceiver using USB interface for easy application to portable devices. It supports the mobility of mobile devices through internet protocol and showed BER performance of less than $10^{-3}dBm$ at over 1m, which is the height of lighting and smart device during walking.