• Journal of the Institute of Convergence Signal Processing
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• v.20 no.2
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• pp.111-117
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• 2019

We investigated the variations in the magnetic-field distribution and power transmission efficiency, resulting from changes in the relative positions of the transmitting and receiving coils, for electromagnetic-induction-type wireless power transmission using an elliptical receive coil. Results of simulations using a high-frequency structure simulator were compared to actual measurement results. The simulations showed that the transmission efficiency could be maintained relatively stable even if the alignment between the transmitting and receiving coils was changed to some extent. When the centre of the receiving coil was perfectly aligned with the centre of the transmitting coil, the transmission efficiency was the maximum; however, the degree of decrease in the transmission efficiency was small even if the centre of the receiving coil moved by ± 10mm from the centre of the transmitting coil. Therefore, it is expected that the performance of the wireless power transmission system will not be degraded significantly even if perfect alignment is not maintained. The results suggested a standardized application method of wireless transmission in the utilization of wireless power for implantable sensors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.421-425
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• 2006

An ubiquitous healthcare system for the home care of elderly persons was designed and implemented using wireless sensor network technology. The wireless technology for home-care purpose gives new possibilities for monitoring of vital parameter with wearable biomedical sensors, and will give the patient the freedom to be mobile and still be under continuously monitoring and thereby to better quality of patient care. Emphasis is placed on recent advances in wireless ECG system for cardiac event monitoring with particular attention to arrhythmia detection in patient. This paper presents a diagnostic system for cardiac arrhythmias from ECG data, using wireless sensor technology. The system also provides an application for recording activities, events and potentially important medical symptoms. The hardware allows data to be transmitted wirelessly from on-body sensor to the base station and then to PC/PDA. Data is also transmitted to a back-end server for analysis using wireless internet connection. Experiments were conducted using the system for activity monitoring, exercise monitoring and medical screening tests and present preliminary data and results.

• Convergence Security Journal
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• v.4 no.3
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• pp.27-35
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• 2004

A current trend in telecommunication is the convergence of wireless communication and computer network technologies, and the emergence of wireless application protocol(WAP) devices is an example. Computer system managers are often requested to solve urgent system problems. Many times, they cannot access a computer to perform remote system management tasks. Aiming at solving this problem, this paper presents a novel tool for system management that uses a WAP interface, and focuses on the description of the architecture and the associated application modules.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2980-2991
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• 2012

Since wireless sensor networks are broadly used in various areas, there have been a number of protocols developed to satisfy specific constraints of each application. The most important and common requirements regardless of application types are to provide a long network lifetime and small end-to-end delay. In this paper, we propose Early Preamble MAC (EP-MAC) with improved energy conservation and low latency. It is based on CMAC but adopts a new preamble type called 'early preamble'. In EP-MAC, a transmitting node can find quickly when a next receiving node wakes up, so EP-MAC enables direct data forwarding in the next phase. From numerical analysis, we show that EP-MAC improves energy consumption and latency greatly compared to CMAC. We also implemented EP-MAC with NS-2, and through extensive simulation, we confirmed that EP-MAC outperforms CMAC.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.233-237
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• 2008

This paper presents proposal for an application (only for Windows-based Mobile) that can synchronize the Third Generation Windows-based mobile with the prescribed server. This application can be used by mobile users to send information directly to the WAS server wirelessly. In this paper a comparison between Third Generation technology and WLAN ( both are parallel technologies first one embodied by IMT-2000 standards and the second one by ITU Standards) has been made and also a comparison between Wi-Fi and Bluetooth has been made.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.396-403
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• 2017

In recent years, the use of touch screens has expanded, and devices such as remote controllers have been developed in various ways to control and access contents at long range. The wireless-based touch screen is used in classroom, seminar room, and remote video conversation in addition to the TV remote control. The purpose of the study is to design a smart phone-based intuitive interface that can perform the role of a wireless mouse and a wireless keyboard at range using Bluetooth and to develop an application that integrates functions of a mouse and a keyboard. Firstly, touch interaction model for controlling software such as PowerPoint by connecting to a general PC on a smart phone has been studied. The most simple touch operation interface is used to reproduce the function of existing devices and design more simply. The studies of the extension of interfaces with various functions are important, but development of optimized interfaces for users will become more important in the future. In this sense, this study is valuable.

• Annual Conference of KIPS
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• 2001.04b
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• pp.1153-1156
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• 2001

지난해부터 무선 인터넷 관련 시장의 급속한 확산으로 인해 사용자들의 다양한 요구에 부응하기 위한 무선 컨텐츠가 요청되고 있다. 그로 인해 개발자가 실제와 같은 상황에서 WML과 WML Script 컨텐츠를 편리하게 테스팅 할 수 있는 환경이 필요하게 되었다. 본 논문에서는 CP(Content Provider)들이 작성된 WML(Wireless Markup Language) 컨텐츠(Content)를 쉽고 편리하게 브라우징하면서 테스팅 하기 위하여 필수적으로 요청되는 WAP(Wireless Application Protocol) Emulator의 설계와 구현에 대하여 기술한다. 본 논문에서는 서술된 WAP Emulator는 WAP 핸드폰에 탑재되는 것과 동일한 기능을 보유하는 WAP 스택 및 WMLScript 가상머신을 지원하여 실제 핸드폰과 거의 유사한 기능을 제공한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1025-1026
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• 2015

With the development of sensor, wireless mobile communication, embedded system and cloud computing, the technologies of Internet of Things have been widely used in real word. Connecting wireless sensor networks with traditional communication networks or Internet, IoT gateway plays an important role in IoT applications. It facilitates the integration of wireless sensor networks and mobile communication networks or Internet. The IoT gateway is a key component in IoT application systems. But It has lot of security issues. We analyzed the issues of security and privacy.

• Journal of the Korea Society for Simulation
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• v.14 no.3
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• pp.33-42
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• 2005

One of the imminent problems to be solved within wireless sensor network is to balance out energy dissipation among deployed sensor nodes. In this paper, we present a transmission relay method of communications between BS (Base Station) and CHs (Cluster Heads) for balancing the energy consumption and extending the average lifetime of sensor nodes by the fuzzy logic application. The proposed method is designed based on LEACH protocol. The area deployed by sensor nodes is divided into two groups based on distance from BS to the nodes. RCH (Relay Cluster Head) relays transmissions from CH to BS if the CH is in the area far away from BS in order to reduce the energy consumption. RCH decides whether to relay the transmissions based on the threshold distance value that is obtained as a output of fuzzy logic system, Our simulation result shows that the application of fuzzy logic provides the better balancing of energy depletion and prolonged lifetime of the nodes.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.101-102
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• 2016

사물인터넷(Internet of Things)의 도래와 함께, 무선공유기(wireless access point)들의 보안이 심각한 문제로 대두되고 있다. 연구진은 대부분의 무선공유기들이 제공하는 웹 기반 관리 인터페이스들에 웹 어플리케이션 취약점(web application vulnerability)들이 존재할 수 있다는 점을 착안, 국내 주요 무선공유기들에 대한 웹 어플리케이션 취약점 점검을 수행하였으며, 악용이 가능한 여러 취약점들이 존재함을 확인하였다. 본 논문에서는 연구진이 무선공유기 대상 웹 어플리케이션 취약점 점검에 보조적으로 사용하기 위하여 개발한 3종의 모바일 앱(mobile app)들을 설명한다.