• Research in Mathematical Education
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• v.4 no.1
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• pp.45-55
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• 2000

The rapid proliferation of wireless networks provides a ubiquitous channel for delivering instructional materials at the convenience of the user. By delivering content through portable devices linked to the Internet, the full spectrum of multimedia capabilities is available for engaging the user's interest. This capability encompasses not only text but images, video, speech generation and voice recognition. Moreover, the incorporation of machine learning capabilities at the source provides the ability to tailor the material to the general level of expertise of the user as well as the immediate needs of the moment: for instance, a request for information regarding a particular city might be covered by a leisurely presentation if solicited from the home, but more tersely if the user happens to be driving a car. This paper presents system architecture to support mobile instruction in conjunction with knowledge-based tutoring capabilities. For concreteress, the general concepts are examined in the context of a system for mathematics education on the Web.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1215-1221
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• 2009

A novel approach for electrocardiogram (ECG) analysis within a functional sensor node has been developed and evaluated. The main aim is to reduce data collision, traffic overload and power consumption in healthcare applications of wireless sensor networks(WSN). The sensor node attached on the patient's body surface around the heart can perform ECG analysis based on a QRS detection algorithm to detect abnormal condition of the patient. Data transfer is activated only after detected abnormality in the ECG. This system can reduce packet loss during transmission by reducing traffic overload. In addition, it saves power supply energy leading to more reliable, cheap and user-friendly operation in the WSN for ubiquitous health monitoring.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.226-234
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• 2005

Context-Aware is the most important facts to reason a personalized and optimized service and to provide it to user. In the previous researches, user and surrounding environment were main facts of Context-Aware and middleware or center server has been proposed to support Context-Aware. In the daily space(for example, home, office, Car, etc), interactions between user and service can be a important facts of Context-Aware. In this paper, Context Autogenesis service model is introduced, simplified the Context-Aware process and designed the middleware which performs decentralize management for Context-Aware information of user's portable devices, so that problems occurred during the management and operation of existing Context-Aware system can be minimized and supporting user anonymity

• Journal of Multimedia Information System
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• v.1 no.2
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• pp.101-110
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• 2014

The purpose of this research is to extend Ad-hoc network system lifetime with the proposed routing protocol which has considered hop lifetimes of the nodes while guaranteeing QoS in the establishment process of Ad-hoc network communication paths. Based on another power aware routing system that proposed in the advanced research [1], we are proposing an alternative power aware routing system in which nodes' hop lifetimes are compared in order to extend the lifetime of an Ad-hoc network system and delay factors have been considered for the assurance of QoS. The research of the routing protocol in this paper, which aims to maximize the system survival time considering power consumption status during the path searching in MANET and pursues the mechanism that controls hop delays for the same reason, can be applied to the study of WSN. The study concerning such phenomena is essential so that the proposed protocol has been simulated and verified with NS-2 in Linux system focusing on the lifetimes of the hops of the nodes. Commercialization of smart devices and arrival of the ubiquitous age has brought about the world where all the people and things are connected with networks. Since the proposed power aware method and the hop delay control mechanism used to find the adequate communication paths in MANET which mainly uses batteries or in WSN, they can largely contribute to the lifetime extension of the network system by reducing power consumptions when utilized for the communications attempts among soldiers during military operation, disaster areas, temporary events or exhibitions, mobile phone shadow areas, home networks, in-between vehicle communications and sense networks, etc. This paper presents the definitions and some advantages regarding the proposed outing protocol that sustain and extend the lifetime of the networks.

• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1059-1071
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• 2008

Users in ubiquitous computing environment can easily access and use a multitude of devices and services anywhere and anytime. The key technology to realize this scenario is the method to intuitively provide proper user interfaces for each device and service. Previous attempts simply provided a designated user interface for each device and service or provided an abstract user interface to control common functions of different services. To select a target appliance, either user directly specified the target device or depended on sensors such as RFID tags and readers limiting the applicable scenarios. In this paper, we present UbiController which uniquely uses camera on the mobile device to recognize markers of appliances to acquire user interface for controlling task. UbiController aims to provide automatic discovery of multiple services in the smart home environment, support traditional GUI and novel camera-based recognition method as well as intuitive interaction methods for users. In this paper, we show experiments on the performance of UbiController's discovery and recognition methods and user feedback on interaction methods from a user study.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.294-308
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• 2009

It is growing a necessity of consideration and management to the relevant policies for the elderly Patriots and Veterans systematically in order to increase the life-supported services since the rapid growth of the aging society. It is difficult to ensure the outcome of cost-effectiveness about the policies because of the residual welfare view and the limitation of the government budget in terms of the traditional Bohun(Korean independent movement activists, veterans and sacrificed advocators for democratization) service, though. In addition, it is not realized the individual activity and daily life-supported services yet to the elderly Patriots & Veterans since the concentration of security income and medical care. Accordingly, it is proper to quest a new Bohun policy from the traditional residual welfare view to universal or ubiquitous welfare service, which will enable them to get the various care service benefit in terms of cost-effectiveness. In this vein, the study is trying to figure out the alternative supply mechanism in-home care service to the elderly Patriots and Veterans; especially, the study emphasizes on the linkage between the regional social welfare service system and Bohun welfare service system.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.13-20
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• 2011

In this paper, we proposed a system to raise gas safety management by using the wireless communication module and intelligent gas safety appliances. Our designed systems configure a micom-gas meter, an automatic extinguisher, sensors, and a wallpad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks gas(combustible) leaks and temperature of $100^{\circ}C$ and $130^{\circ}C$. Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals for smoke and CO when occurring gas risk. Gas safety appliances and sensors takes safety measures, and transmit those signal to a wallpad. The wallpad again transmit signal like events to a control server. Users can connect web pages for gas safety through B-ISDN and control and manage them. We hereby devised scenarios for gas safety and risk management, and demonstrated their effectiveness through experiments.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1509-1520
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• 2009

Contrary to ubiquitous environments, indoor computing environments like home network doesn't support user mobility. This paper suggests UPnP A/V multimedia system using prediction of mobility for adaption of seamless multimedia service. The multimedia system enables indoor mobile users to play multimedia contents by transferring the current session to an adjacent device automatically. The system represents users' contextual information by Five Ws and One H model, and predicts user's movements by using contextual information and transitions of locations. The prediction basically includes multiple locations so that it improves accuracy of prediction. We evaluated the suggested system using in accuracy of prediction, time for prediction, handover time for service, and the system showed that adapt ion of seamless multimedia service was enabled by using prediction of mobility on mobile user.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.1-10
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• 2011

In this paper, we proposed the skin color based hand and finger detection technology for the gesture recognition in CCTV surveillance. The aim of this paper is to present the methodology for hand detection and propose the finger detection method. The detected hand and finger can be used to implement the non-contact mouse. This technology can be used to control the home devices such as home-theater and television. Skin color is used to segment the hand region from background and contour is extracted from the segmented hand. Analysis of contour gives us the location of finger tip in the hand. After detecting the location of the fingertip, this system tracks the fingertip by using only R channel alone, and in recognition of hand motions to apply differential image, such as the removal of useless image shows a robust side. We explain about experiment which relates in fingertip tracking and finger gestures recognition, and experiment result shows the accuracy above 96%.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.325-331
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• 2007

Personal identification is essential for the automatic measurement of biosignal information in home healthcare systems. Personal identification is usually achieved with passive radio frequency identification (RFID), which does little more than store a unique identification number. However, passive RFID is not ideal for automatic identification. We present a user identification system based on radio signal strength indication (RSSI) using ZigBee for active RFID tags. Personal identification is achieved by finding the largest RSSI value from aggregated beacon messages that are periodically transmitted by active RFID tags carried by users. Obtaining reliable person!'.! identification without restricting the orientation requires a certain distance between the closest active RFID tag from the ZED and the second closest tag. The results show that the closest active RFID tag from the ZED and the second closest tag must be at least 70 cm apart to achieve reliable personal identification.