• 제목/요약/키워드: wireless modem

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Implementation of Embedded System for IEEE802.11p based OFDM-DSRC Communications (IEEE802.11p 기반의 OFDM-DSRC 통신을 위한 임베디드 시스템 구현)

  • Kwak, Jae-Min
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.11
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    • pp.2062-2068
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    • 2006
  • In his paper, embedded system implementation for IEEE802.l1p based OFDM-DSRC is presented. After the IEEE802.11p physical layer specification is introduced and BER performance of the modem is evaluated by simulation, implementation aspects of the system such as system architecture, design method and implementation results are addressed. Implemented embedded system for the OFDM-DSRC communication consists of FPGA, flash memory, ARM9 CPU Core, peripherals, etc. from the results, it is shown that the implemented system operates well according to IEEE802.11p specification. It is expected that implemented embedded system shall be used for wireless communication system such as ITS application by enhancing system optimizing.

A Study on Security Framework in Digital Home Environments (디지털홈 환경에서의 보안 프레임워크 연구)

  • 김도우;한종욱;주홍일;이윤경
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05b
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    • pp.724-727
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    • 2004
  • With the development of modem communication and networking technology, more and more computing and communication facilities, automation equipments, hone information appliances and different type of networking terminals come into home all over the world. The user can control information appliances in home environments. The home environment can communicate with the external network via phone line, wired LAN, wireless LAN, or mixed. However, home information appliances that are connected to the external network are under attack and need to be secured. So specifying suitable security requirements and policies for digital home environment is critical in hone networking environments. This paper analyzes the possible vulnerability to home network, and specifies the security requirements derived from the vulnerability analysis for digital home environment

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Monitoring System with PLC I/O for Car Parking Lot (Car Parking Lot 모니터링 시스템)

  • Lee, Seong-Jae;Kim, Jae-Yang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.511-512
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    • 2007
  • The monitoring system has won acceptance as a premium mark that identifies the highest standard of product quality in advanced industry. The TOP features with multi-I/O ports and VGA & RCA TV-out ports supporting mirroring & multiple dual-display modes by windows 0/5. With the choice of versatile stands, panel mount, or VESA wall-mount swing arm and connecting to modem. Wireless keyboard, Customer Display and Card Reader, is your idea Panel system for the application of TOP(Touch Operation Pannel), KIOSK, or Office / Factory Automation. TOP is the hardware and software product that transacts all kind of functions for advanced technology equipment to button, switch, voice and graph etc so that let consumer use easily Industrial HMI System Touch Panel. System characteristics: Easy of use and flexibility to the user, Present a high value solution and advanced function for many Application, Factory Automation, Office Automation, Building Automation System, Information Service System, etc. Analog Touch - 2MB Flash Memory for Saving Screen Data - RS-232C/422 Serial Port - Multi Language Support.

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A Coherent-based Symbol Detector for 2.45GHz LR-WPAN Receiver (2.45GHz LR-WPAN 수신기를 위한 Coherent 기반의 Symbol Detector)

  • Han Jung-Su;Do Joo-Hyun;Park Tha-Joon;Choi Hyung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.2A
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    • pp.176-186
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    • 2006
  • In this paper, we propose an enhanced symbol detector algorithm for 2.45GHz LR-WPAN(Low-Rate Wireless Personal Area Network) receiver. Because the frequency offset of $\pm$80ppm on 2.45GHz band is recommended in IEEE 802.15.4 LR-WPAN(Low-Rate Wireless Personal Area Network) specification, a symbol detector algorithm having stable operation in the channel environment with large frequency offset is required. For robustness to the frequency offset, non-coherent detection-based symbol detector algorithm is typically applied in the LR-WPAN receiver modem. However, the noncoherent symbol detector has increased performance degradation and hardware complexity due to squaring loss of I/Q squaring operation. Therefore we propose a coherent detection-based symbol detector algorithm with frequency offset compensation using a preamble symbol. The proposed algorithm is more suitable for LR-WPAN receiver aimed at low-cost, low-power and low-complexity than the non-coherent symbol detector, since it can reduce performance degradation due to squaring loss of I/Q squaring operation and implementation complexity. Simulation results show that the proposed algorithm has performance improvement of about 1dB in various channel environments.

Construction of Information System for Management of Cultural Heritage on the Web Using a Pilotless Helicopter Photogrammetry System (무인 헬기 사진측량시스템을 이용한 Web 상에서의 문화재 관리 정보시스템 구축)

  • 이종출;양인태;장호식;허종호
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2004.04a
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    • pp.389-394
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    • 2004
  • Structure-typed cultural heritage, objects of preservation are positioned as one of the very important heritage in the nation, and the preservation of prototypical structures become influential in national development and against natural disaster. For this reason, Digital Close Range Photogrammetry has recently been diversely used. Despite its popular use, the measurement has limits that make it unsuitable for photographing precise cultural heritage situated at high mountainous terrain or where people can not approach easily. These high gigantic stone statues are among the preserved structure-typed cultural heritage. In order to supplement the limits, when using the measurement, a camera tripod with +30m, a ladder truck and a shore should be equipped, which means additional equipment leads to it being a waste of cost and time. In this vein, a device was developed in detail, using a RC Helicopter installed with a CCD video camera with ease of control, safety, equipment, carrying, movement and approach, then checked image shot by a wireless modem at real time and considered the economical efficiency without re-photographing. Next, the author digitized the images of the nationally designated structure-typed cultural heritage, used materials on their restoration as the third dimension in order to construct the integrated management-information system for cultural heritage. Through the above processes, this study can provide specific information on 3D images and 3D CAD sections of structured-typed cultural heritage for both the public and specialists on the web. Moreover, it suggests the foundation to restore the damaged cultural heritage in the future by aiming for their effective management and preservation.

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Current to Voltage Converter for Low power OFDM modem (저전력 OFDM 모뎀 구현을 위한 IVC설계)

  • Kim, Seong-Kweon
    • The Journal of the Korea institute of electronic communication sciences
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    • v.3 no.2
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    • pp.86-92
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    • 2008
  • Othogonal Frequency Division Multiplexing(OFDM) has been taken notice of 4th generation communication method because it has a merit of high data rate(HDR). To realize HDR communication, The OFDM a s high efficient Fast-Fourier-Transform (FFT)/Inversion FFT (IFFT) processor. Currently OFDM is realized by Digital Signal Processor(DSP) but it consumes a lot of Power. Therefore, current-mode FFT LSI has been proposed for compensation of this demerit. In this paper, we propose IVC for current-mode FFT LSI. From the simulation result, the output value of IVC is more than 3V when the value of FFT Block output is more than $7.35{\mu}A$. The output value of IVC is lower than 0.5V when the value of FFT Block output is lower than $0.97{\mu}A$. Designed IVC Low-power Current mode FFT LSI will contribute to the operation of current-mode FFT LSI and the development of next generation wireless communication systems.

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A Fast XML Encoding System for Fast Web Services (Fast 웹서비스를 위한 Fast XML 인코딩 시스템)

  • Kim, Jong-Moon;Yu, Lei;Hong, Xian-Yu;Choi, Bong-Kyu;Jung, Hoe-Kyung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.06a
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    • pp.865-868
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    • 2007
  • Web service in operating environment independent XML about under using, It dose so, Integration of the platform for it is different each other possibly it is doing. But XML in order to have the text data which is unnecessary plentifully with wireless Internet or the mobile communication modem in together relatively will connect frequently slow communication medium and there is a problem point which decreases the case prerequisite efficiency which the resources will use from the limited small-sized machinery and tools. Hereupon XML about under make binary the standard which reduces the size of the document from ITU-T and ISO/IEC it was under proposing with commonness, currently binary XML encoding where it is in the process of advancing standard there are Fast Infoset and Fast Schema. In this paper, implementation of Fast XML encoding system through introduction Fast Infoset algorithm and Fast Schema algorithm for web services increase performance.

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The Design and Implementation of the Data Link System based on the Off-the-shelf Ultra Mobile Personal Computer for Network Centric Warfare(NCW) (네트워크중심전(NCW)을 위한 UMPC 기반 데이터 링크 시스템 설계 및 구축)

  • Sim, Dong-Sub;Kim, Ki-Hyung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.2
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    • pp.175-181
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    • 2009
  • All of the military aircrafts in Korea Air Force are administered and operated together in the same system regardless of whether they are equipped with the data communication capability or not. The absence of the data communication capability in some of the aircrafts might increase whole kill chain hour at the point of the Network Centric Warfare achievement. Network synergy effects cannot also be desired if the section which is not connected to the network influences to the whole tactical network. Equipping aircrafts with the data communication capability could be done by upgrading the aircrafts, but resulting in high costs and long updating time. This paper is a research about the design and implementation of the UMPC based Data Link System to aircrafts that do not have the data communication capability. The proposed system grafts the UHF-based wireless modem technology and the aircraft flight mission support software onto the off-the-shelf UMPC and GPS system. The employed UHF radio equipment allows communicating tactic data with another aircrafts on the air, the ground control point, and even the Tactical Air Control Party(TACP) control vehicle that achieve missions with aircrafts. It thereby increases such capabilities as navigation aid, situation awareness, quick target identification and attack. We also applied Closed Air Support(CAS) scenarios, which is very close to the real environment, to the experiments of the proposed system. The experimental results show that the proposed system could support the data communication capability effectively and the flight mission at low costs of money and time.

Development of the off-vertical rotatory chair and visual stimulation system for evaluation of the vestibular function (전정기능 평가를 위한 탈수직축 회전자극 시스템 및 HMD 시스템의 개발)

  • 김규겸;고종선;박병림;김인동
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.4
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    • pp.325-332
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    • 2001
  • The vestibular system located in the inner ear controls reflex body posture and movement, It has the semicircular canals sensing an angular acceleration and the otolith organs sensing a linear acceleration. With this organic signal, medical doctor decide if a person has disease or not. To obtain this data, a precision stimular system is considered. Robust control is needed to obtain eye signals induced by off-vertical axis rotation because of an unbalanced load produced by tilting the axis of the system upto 30 degrees. In this study, off-vertical axis rotatory system with visual stimulation system are developed. This system is consisted of head mounted display for generating horizontal, vertical, and three dimensional stimulus patterns. Furthermore wireless recording system using RF modem is considered for noiseless data transmission. Detailed data was described.

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Stacked LTCC Band-Pass Filter for IEEE 802.11a (IEEE 802.11a용 적층형 LTCC 대역통과 여파기)

  • Lee Yun-Bok;Kim Ho-Yong;Lee Hong-Min
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.2 s.93
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    • pp.154-160
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    • 2005
  • Microwave Otters are essential device in modem wireless systems. A compact dimension BPF(Band-pass Filter) for IEEE 802.11a WLAN service is realized using LTCC multi-layer process. To extrude 2-stage band-pass equivalent circuit, band-pass and J-inverter transform applied to Chebyshev low-pass prototype filter. Because parallel L-C resonator is complicate and hard to control the inductor characteristics in high frequency, the shorted $\lambda/4$ stripline is selected for the resonator structure. The passive element is located in the different layers connected by conventional via structure and isolated by inner GND. The dimension of fabricated stacked band-pass filter which is composed of six layers, is $2.51\times2.27\times1.02\;mm^3$. The measured filter characteristics show the insertion loss of -2.25 dB, half-power bandwidth of 220 MHz, attenuation at 5.7 GHz of -32.25 dB and group delay of 0.9 ns at 5.25 GHz.