• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.331-334
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• 2002

This paper discribes the differen-ces between making handset sample and handset massproductions. To save time during mass production, Calibrat-ion should be automated and SW do-wnloading also be automated and Par-allely done. All this processes are des-cribed here. Especially Calibration are more detaily explained in this paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2899-2902
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• 2003

Mobile communication is one of the fastest growing industries in the world and especially in Korea, where we have well over 30 million voice subscribers. Mobile communication now offers variety of data communication services such as wireless internet, multimedia messages, and color graphic displays. Handsets also have grown to accommodate such services, thus with functionalities such as programmable virtual machines that users can download and execute their own programs. In this paper, we have demonstrated a PCS handset monitoring system which can monitor biometry signals - in this case ECG over wireless internet and wireless data network (IS95C) based on programmable virtual machine architecture. The remote client handset receives data signals from a centralized server and processes and displays them in human friendly form in real time. Since every single handset on sales in Korea has programmable virtual machine and more than 10 million handsets are in distribution already, proper applications may have substantial impact on the related fields.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권2호
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• pp.72-74
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• 2006

In this paper, a wireless multimedia service interacting with key input of a phone number is Presented. In the conventional handset, when the key button is pressed, numbers are displayed or the embedded sound is played. Also, the contents are fixed and cannot be changed. In this paper, we propose a wireless multimedia service playing multimedia contents in accordance with the key input of a phone number. The contents can be downloaded from the wireless internet server. To implement this service, file format, fast codec and download structure are proposed. Using the presented structure, this service is being provided by a telecommunication company in Korea. Various applications based on this service are being expected.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 추계종합학술대회
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• pp.363-367
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• 1999

인터넷 서비스와 무선통신 서비스의 급속한 가입 증가로 미래의 통신망 트래픽은 무선 통신을 이용한 인터넷 어플리케이션이 주가 될 것으로 전망된다. 현재 진행중인 무선통신 기술은 화면이 크고 메모리가 넉넉한 개인용 컴퓨터나 노트북을 대상으로 멀티미디어 데이터를 주고 받기 위한 것들이다. 그러나 이미 많이 보급되어 있는 핸드폰이나 PDA 등을 사용한 인터넷 서비스 접속에 대한 요구도 크게 늘어날 것이다. 따라서 작은 화면과 저용량의 메모리, 낮은 처리 능력 등을 특징으로 갖는 판막기가 무선환경에서 인터넷 서비스를 접속하기 위한 새로운 프로토콜에 대한 요구가 등장하였고 이를 위하여 세계자국의 단말기 회사가 중심이 된 WAP(Wireless Access Protocol) 포럼이 결성되어 표준안 작업이 활발히 진행중이다. 본 논문에서는 WAP의 기본 구조 및 프로토콜을 소개하고 기존의 HTML 문법으로 작성된 문서들을 WAP에서 제안하는 WML 형식으로 수용하기 위하여 필요한 요구사항들을 제안하며 기존의 웹사이트를 WML 문법으로 변환하였을 때 무선망에서 얻게되는 압축률을 보인다.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.151-155
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• 2010

Reconfigurable radio technology is needed to reconstruct frequency and modem functionality, which can be different in various regions. In addition, it makes a single mobile handset capable of supporting various standards of wireless communication and thus plays a key role in mobile convergence. An MMIC VCO (voltage controlled oscillator) has been developed for high power and wide bandwidth where Clapp-Gouriet type oscillators are adapted for series feedback, and was fabricated based on 0.15um pHEMT of TRW. The MMIC VCO was connected to an aluminar substrate on the carrier for testing. This MMIC VCO module showed good performance in comparison to existing works. Furthermore, it can be potentially extended to reconfigure an MMIC VCO for wireless systems such as military applications and satellite communications.

• 한국멀티미디어학회논문지
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• 제8권12호
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• pp.1649-1657
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• 2005

In this paper, a fast implementation of JPEG is discussed and its application to multimedia service is presented for mobile wireless internet. A fast JPEG player is developed based on several fast algorithms for mobile handset. In the color transformation, RCT is adopted instead of ICT for JPEG source. For the most time-consuming DCT part, the binDCT can reduce the decoding time. In upsampling and RGB conversion, the transformation from YCbCr to RGB 16 bit is made at one time. In some parts, assembly language is applied for high-speed. Also, an implementation of multimedia in mobile handset is described using MJPEG (Motion JPEG) and QCELP(Qualcomm Code Excited Linear Prediction Coding). MJPEG and QCELP are used for video and sound, which are synchronized in handset. For the play of MJPEG, the decoder is implemented as a S/W upon the MSM 5500 baseband chip using the fast JPEG decoder. For the play of QCELP, the embedded QCELP player in handset is used. The implemented multimedia player has a fast speed preserving the image quality.

• 한국정보기술학회 영문논문지
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• 제9권2호
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• pp.99-105
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• 2019

In this paper, we describe the procedure of simulation design and measured results of a compact planar antenna for handset applications. The broad bandwidth covering the interested frequency band for mobile handset is achieved by introduction of an open ended L-shaped slot which is newly proposed and corresponds to the monopole slot. In order to minimize the impact on circuit part placement, the proposed antenna is placed on the ground plane edge of PCB with size of 60×65 mm². The measurement result for 10dB impedance bandwidths is 640 MHz (1.7~2.34 GHz), covering the required bandwidths for DCS (Digital Cellular System)-1800 (1710 ~ 1880 MHz) / IMT (International Mobile Telecommunication)-2000 (1885 ~ 2200 MHz) bands. In particular, we would like to emphasize the proposed antenna has an omnidirectional radiation pattern suitable for commercial wireless communication.

• 한국멀티미디어학회논문지
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• 제8권6호
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• pp.827-835
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• 2005

In this paper, self-networking and replaceable structure in vector graphics contents are presented for wireless internet service. The wireless networks over 2G or 3G are limited in the sense of the speed and the cost. Considering these characteristics of wireless network, self-networking method and replaceable structure in downloaded contents are introduced in order to save the amount of data and provide variations for contents. During the display of contents, a certain data for the contents is downloaded from the server and it is managed appropriately for the operation of the contents. The downloaded materials are reflected to the original contents using replaceable structure. Also, the downloading and modification are independent of the play. In this implementation, the data consists of control data for control and resource data for image, sound or text. Comparing to the conventional methods which download the whole data, the amount of the transmitted data is very small since only the difference is downloaded. Also, during the play of the contents, the changes are adopted immediately. The whole functions are implemented in wireless handset and the various applications are discussed.

• 정보보호학회논문지
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• 제17권6호
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• pp.41-56
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• 2007

본 논문에서는 국내 무선인터넷 표준 플랫폼 규격인 WIPI(Wireless Internet Platform for Interoperability)에 적합한 Specification 기반의 침입탐지시스템을 제안한다. 시스템을 제안함에 있어서는 경량의 단순화된 코드, C와 자바 등의 다양한 언어 수용성 그리고 하드웨어 독립성을 고려하였다. 제안한 침입탐지시스템은 WIPI HAL(Handset Adaptation Layer)의 주요 AP 대상으로 침입을 탐지하는 알고리즘에 기반하고 있으며, HAL API에 추가 가능한 형태의 mIDS(mobile Intrusion Detection System) API 그룹을 프로토타입으로 정의하였고, 자바 라이브러리와 WIPI 에뮬레이터를 이용한 시뮬레이션을 통해 적용 가능성을 증명하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권4호
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• pp.249-256
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• 2009

As a wireless handset deals with multiple application standards concurrently, RF transmitters and power amplifiers are required to be more power efficient and reconfigurable. In this paper, we review the recent advances in the design of the power amplifiers and transmitters. Then, the systematic design approaches to improve the performance with the digital baseband signal processing are introduced for the next generation mobile handset.