• Title/Summary/Keyword: wireless application

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Design of Power Detection Block for Wireless Communication Transmitter Systems (무선통신 송신시스템용 전력검출부 설계)

  • Hwang, Mun-Su;Koo, Jae-Jin;Ahn, Dal;Lim, Jong-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1000-1006
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    • 2007
  • This paper presents a power detector circuit which monitors the transmitting power for the application in CDMA cell phones. The proposed power detector are composed of coupler for coupling output power and detector fur monitoring output power. The designed coupler has low loss characteristic because it adopts the stripline structure which consists of two ground planes at both sides of signal plane. The design frequency is 824-849MHz which is the Tx band fur CDMA mobile terminal, and the coupling factor of the stripline coupler is -20dB. A schottky barrier diode is adopted for detector design because of its high speed operation with minimized loss. The required impedance matching is performed to improve the linearity and sensitivity of output voltage at relatively low detector input level where the nonlinear characteristic of diode exists. The package parasitics as well as intrinsic diode model are considered for simulation of the detector. The predicted performances agree well with the measured results.

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Implemetation of OFDM Ethernet Modem System (고속이동체를 위한 OFDM Ethernet 모뎀 시스템 구현)

  • Jeong, Sang-Guk;An, Tae-Ki;Kim, Back-Hyun;Nam, Myung-Woo;Lee, Yong-Seok;Oh, Myung-Kwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.4
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    • pp.1817-1823
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    • 2011
  • OFDM Modulation is used for multimedia transmission At Urban Train. Recently the application field about data transmission is expanding the image as well. The case which the number of OFDM carrier is big is advantageous because multipass fading is big 18GHz wireless frequency. Existing WLAN which an ethernet transmission is possible is not suitable to a great distance transmission because number of carrier is 64. In this paper, we developed OFDM modem suitable to transmit broadband data at high speed train. A doppler compensation block added to offset the doppler effect. Therefore, the effectiveness is expected to be very big in field of urban train.

Design of Worker's Safety Management System by Monitoring Work Location and Sensing Danger Zones (위험구역 접근 센싱 및 작업위치 모니터링을 이용한 작업자 안전관리 시스템 설계)

  • Min, So-Yeon;Lee, Kwang-Hyoung;Park, Jeong-Hyo;Lee, Keun-Wang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.7
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    • pp.3236-3244
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    • 2011
  • Negligent accidents are often caused by risk factors of working environment at most construction sites and construction schedules are delayed as the workers' work location and construction progress are not figured out accurately, and this leads to a lot of loss. In this paper, with the object of solving the problems at construction sites, RFID portable device, active tag and wireless RFID reader to provide the status of workers which is based on location are designed in order to send information about the location of workers and work progress in real time to a personal RFID device. Also an application system to monitor workers' approaching to prevent accidents from vehicles and danger zones and to manage the real time location of workers is designed.

Control of Microbial Shelf Life of Perishable Food by Real-Time Monitoring of $CO_2$ Concentration of its Package (변패성 식품의 포장 내 $CO_2$ 농도의 실시간적 측정에 의한 미생물적 저장수명 제어)

  • Kim, Hwan-Ki;An, Duck-Soon;Lee, Hyuk-Jae;Lee, Dong-Sun
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.17 no.2
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    • pp.33-37
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    • 2011
  • Real time control logic of microbial shelf life of a perishable food, seasoned pork meat has been formulated which exploits monitoring of $CO_2$ concentration of the package. The potential of the proposed logic was examined for storage at dynamic temperature conditions. The start of increase in $CO_2$ production rate from the food or rate of package $CO_2$ concentration change was found to coincide with the point of microbial quality limit and could be used as an index of microbial shelf life determination. This also corresponded to lag time of $CO_2$ concentration change or time for the $CO_2$ concentration to reach a certain value. The application potential of the proposed logic was confirmed for a sensor system to measure on real time and transmit the $CO_2$ concentration wireless to the computer system.

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Expansion of Sample OD Based on Probe Vehicle Data in a Ubiquitous Environment (유비쿼터스 환경의 프로브 차량 정보를 활용한 표본 OD 전수화 (제주시 시범사업지역을 대상으로))

  • Jeong, So-Young;Baek, Seung-Kirl;Kang, Jeong-Gyu
    • Journal of Korean Society of Transportation
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    • v.26 no.4
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    • pp.123-133
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    • 2008
  • Information collection systems and applications in a ubiquitous environment has emerged as a leading issue in transportation and logistics. A productive application example is a traffic information collection system based on probe vehicles and wireless communication technology. Estimation of hourly OD pairs using probe OD data is a possible target. Since probe OD data consists of sample OD pairs, which vary over time and space, computation of sample rates of OD pairs and expansion of sample OD pairs into static OD pairs is required. In this paper, the authors proposed a method to estimate sample OD data with probe data in Jeju City and expand those into static OD data. Mean absolute percentage difference (MAPD) error between observed traffic volume and assigned traffic volume was about 22.9%. After removing abnormal data, MAPD error improved to 17.6%. Development of static OD estimation methods using probe vehicle data in a real environment is considered the main contribution of this paper.

RFID Authentication System with ID Synchronization (ID 동기화를 가지는 RFID 인증 시스템)

  • Park Jang-Su;Lee Im-Yeong
    • Journal of Korea Multimedia Society
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    • v.9 no.5
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    • pp.615-623
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    • 2006
  • It has been estimated that 'RFID' technology would be playing an important role in the incoming ubiquitous environment. For this reason, many studies on 'RFID' have been conducted and its application has been on the increase in various fields such as finance, medicine, transportation and culture as well as in logistics distribution. However, the communication between Tag and Reader in RFID system has been conducted by wireless communication of radio frequency so that the information on identification could be eavesdropped by the third party maliciously. Such eavesdropped information could be also used as basic information in attacking others; in this regard, it could impair the privacy of its users and the users have avoided using 'RFID.' To solve theses problems, many studies are being performed to different output of tags by renewing ID. However, protocols have been devised without considering an ID Synchronization in the ID renewal process between database and tag in the existing studies. In this regard, this study has suggested a RFID Authentication Protocol while considering the ID Synchronization.

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Fault Tree Analysis and Fault Modes and Effect Analysis for Security Evaluation of IC Card Payment Systems (IC카드 지불결제 시스템의 보안성 평가를 위한 고장트리 분석(FTA)과 고장유형과 영향 분석(FMEA))

  • Kim, Myong-Hee;Jin, Eun-Ji;Park, Man-Gon
    • Journal of Korea Multimedia Society
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    • v.16 no.1
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    • pp.87-99
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    • 2013
  • The demands of IC card payment system has been increased according to the rapid advancement of the IT convergence application technologies. Recently IC card payment systems are in demands of the usage space at anytime and anywhere by developing the wireless communication technology and its related multimedia processing technology. Therefore the security of IC card payment system becomes more important and necessary. There are many fault analysis methods to evaluate the security and safety of information systems according to their characteristics and usages. However, the only assessment method to evaluate the security of information systems is not enough to analyse properly on account of the various types and characteristics of information systems by the progress of IT convergence and their applications. Therefore, this paper proposes an integrative method of the Fault Tree Analysis (FTA) and Fault Modes and Effect Analysis/Criticality (FMEA/C) based on criticality to evaluate and improve the security of IC card payment system as an illustration.

Design and Parameter Optimization of Virtual Storage Protocol (iATA) for Mobile Devices (모바일 기기를 위한 가상 스토리지 프로토콜(iATA)의 설계 및 파라메터 최적화)

  • Yeoh, Chee-Min;Lim, Hyo-Taek
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.2
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    • pp.267-276
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    • 2009
  • Nowadays, numerous of valuable internet services are available not only for personal computer but also for mobile appliances in wireless network environment. Therefore, as the amount of contents is increased for those services, the storage limitation on mobile devices has became a significant issue. In this paper, we present a new block-level storage network protocol, iATA (Internet Advanced Technology Attachment) as a solution to the above problem. iATA is designed to transport ATA block-level data and command over the ubiquitous TCP/IP network. With iATA, a mobile appliance is able to access and control the ATA storage devices natively through network from anywhere and at anytime as if the storage devices is attached locally. We describe the concepts, design and diverse consideration of iATA protocol. Based on the benchmark experiments and application exploitation, we strongly believe that iATA as a light-weight protocol is efficient and cost-effective to be used as a storage network protocol on a resource limited device that utilizes common-off-the-shelf storage hardware and existing IP infrastructure.

Seamless handover protocol to reduce handover latency (핸드오버 지연 시간을 줄일 수 있는 심리스 핸드오버 프로토콜 제안 및 성능 분석)

  • Jang, Jong-Min;Lee, Yu-Tae;Lee, Soong-Hee;Kim, Dong-Il;Choi, Sam-Gil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.2
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    • pp.277-284
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    • 2009
  • With significant development in wireless communication technologies, the needs to handover from one network to another have grown dramatically. Recently IETF developed MIPv6 and FMIPv6 which are used to handover between different access networks. These handover mechanisms have some known weaknesses. MIPv6 can not serve time-critical application because it causes long handover latency and packet loss. By these reasons, MIPv6 does not guarantee session continuity. FMIPv6 uses handover preparation phase to reduce DAD latency. However FMIPv66 still suffers from long handover latency, because it must perform binding update at the end of handover procedure. In this paper we propose new handover mechanism FMIPv6-PBU which eliminates binding update latency. The proposed mechanism has compatability with lagacy FMIPv6. In this paper propose FMIPv6-PBU handover procedure and explain its procedures and evaluate it with MIPv6 and FMIPv6.

A Study on OFDM Technique for High-speed Data Transmission in Underwater (수중에서 고속 데이터 전송을 위한 OFDM 기법 적용성 연구)

  • Han, Jeong-Woo;Kim, Se-Young;Kim, Ki-Man
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.10
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    • pp.1780-1786
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    • 2008
  • The performance of underwater wireless communication system is influenced on channel characteristic. Especially, a delay spread cause by reverberation and multi-path happen the ISI (Inter Symbol Interference) and reduces the communication performance. In this paper, we study the application of high speed data transmission in underwater to use the OFDM (Orthogonal Frequency Division Multiplexing) technique for robust the reverberation and multi-path. we confirm the performance of communication in underwater to use the model for actually underwater channel simulation model. As a result, we acquired the BER of modulation techniques. The BER of single carrier is $2{\times}10^{-1}$ and BER of multi currier is $8{\times}10^{-2}$ in 1000m. Transmission of single carrier is 5 kbps.