• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1658-1667
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• 1994

In a cellular mobile communication control system, assignment channel for a call in a cell so as to achieve high spectral efficience is an important problem within limited frequence bandwidth. The spectral efficiency is related to the coloring problem of graph theory in a cellular mobile communication control system. In this paper, we propose channel offset scheme using a graph theory of cellular mobile communication control system and formulate chromatic bandwidth of channel offset system which is related graph coloring problem. From formulated channel assignment problem, we investgate an optimal channel offset scheme of more efficent frequence spectrum and cell design according to channel constitution and give and upper and lower bound for overall srectral bandwidth.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.9-14
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• 2016

The Korea Communication Commission(KCC) measures communication qualities of mobile phones' voice calls, mobile internet, and broadband internet to provide quality communication services. It particularly focuses on measuring qualities of mobile internet data that is on the rise in terms of usage. However, existing quality measurement simply measures the speed of mobile communication through data without providing much information to users and does not disclose measured data, making it hard for individuals to objectively determine their communication quality. Thus, to improve such problems, the author suggests a system that measures qualities of mobile communication through Android. The method guarantees user convenience and reliability and improved mobile communication by making it easy for users to select the quantity of data to be used. It also saves the current GPS obtained through GPS module or mobile communication network and transfers measured data to servers so that the data can be processed into new information and be reinterpreted.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.85-90
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• 2005

The advance of mobile and telematics technologies has produced vehicles with various convenient services for drivers. Specifically lots of researches and several technologies have been developed to provide services of a remote vehicle diagnosis and control. The existing and representative product for a vehicle control is a RCS (remote control system), but it has a problem of short control distance and fragile security. In this paper, a telematics terminal embedded with CDMA and GPS is designed, which can be connected to the Internet. It allows a driver with a cellular phone to remotely diagnosis and control a vehicle via wireless network and SMS.

• International Journal of Contents
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• v.5 no.4
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• pp.62-68
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• 2009

This paper presents a novel method to design and implement mobile u-health system by defining the essential elements of mobile healthcare services. We choose common service elements for the proposed u-healthcare scheme and design the service platform. Especially we focus on automatic feces or urine sensing u-care scheme to prove the effectiveness of our platform. We construct the system with sensing part with a manikin and a diaper wireless communication part with feces or urine sensing data, and coordinator system based on the u-health platform defined in this paper. Experimental results show that our scheme is useful in the area of u-care service for the handicapped, the elderly, and patients who can hardly move by themselves. In addition the designed scheme offers a realized u-care scheme with the purpose of advanced developing tools for application or service developers.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.323-326
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• 1996

In this paper, we propose a new method of the communication system for cooperative behavior and control in a collective autonomous mobile robots. A communication function among the collective robots is essential to intelligent cooperation. In general, global communication is effective for small number of robots. However when the number of robot goes on increasing, this becomes difficult to be realized because of limited communication capacity and increasing amount of information to handle. And also the problems such as communication interference and improper message transmission occur. So we propose local communication system based on infrared sensor to realize the cooperative behavior and control as the solution of above problem. It is possible to prevent overflow of information and exchange of complex information by combining communicate a specific robot. At last we verify the effectiveness of the proposed communication system from example of cooperative behavior.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.101-104
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• 2001

Many applications are developed on variety type of mobile terminal with mobile tole-communication improvement. We suggest that we offer more improve multimedia environment on that development. So we design SWF player which supports Macromedia SWF file format. It is application that animation and graphic module are independent of system. In addition to, we implement SWF player on mobile communication environment. for the purpose of it, we adapt AKL concept, which is designed for the consistent interface on heterogeneous operating system environment.

• Journal of Communications and Networks
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• v.4 no.4
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• pp.321-335
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• 2002

Emergence of the fourth generation mobile communication system (4G system) is now in its dawn. This article proposes a perspective framework on the 4G system, and discusses various kinds of system aspects and technological requirements in terms of novel service features, spectrum management, radio access technologies, wired access integration, core network, and mobile terminal. The focus of the article is to define the scope and features of the 4G system in an overall system/network viewpoint. From the foreseeable development trends, it is highly expected that whatever emerges in the 4G system will be some kind of constantly evolving and grand recursive concatenation of all the existing system/network developments.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.58-69
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• 2014

To cope with sever accident like Fukushima accident, the emergency response system is needed. It consist of the hardened I&C system and the mobile control station. The hardened I&C system monitors the state in the nuclear power plant and controls the emergency equipment such as valves, pumps and the mobile control station placed at 30km away from nuclear power plant receives the status information from the hardened I&C system and transmits the control data to the hardened I&C system. In this paper, we design the emergency communication system connecting the hardened I&C system to the mobile control station and analyze the performance of the system. This system consists of the terrestrial communication system and the satellite communication. The performance such as a communication link budget, throughput and delay time is analyzed for each system.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.214-220
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• 2010

In this paper, we developed component for constituent of mobile robot system using RTC which is adapted as an international standardization among the robot middleware technology. We implemented one system by connecting the f elements of mobile robot constituent to each other and performed performance test on mobile robot system using real mobile robot NRLAB 02 that were implemented.

• Journal of Information Technology Applications and Management
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• v.12 no.3
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• pp.97-109
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• 2005

The internet and wireless communication technologies are creating ubiquitous environments in which various services are expected anytime and anywhere. Many hardware facilities have been developed and system structures are suggested for mobile services to realize a ubiquitous computing environment with appropriate quality. But these applications are not designed in the consideration of the general capabilities to perform user's wireless and mobile communication/transaction. Consequently, different needs from users are not sufficiently satisfied yet. In this study, we suggest structure of the emerging network system for mobile commerce that provides users with seamless and ubiquitous environments using location information which exploit context-aware technology.