• Title/Summary/Keyword: Wireless Communication Environment

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The Energy-Efficient Automatic Power Controller of The Signboard using Illuminance Detector (조도 감지기를 이용한 절전형 간판 자동 전원 제어기)

  • Ra, Seung-Tak;Lim, Song-Hwan;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.20 no.2
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    • pp.188-191
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    • 2016
  • In this paper, we propose energy-efficient automatic power controller which can power on and off the signboard at the specified light intensity using the Illuminance Detector. By using segmented section Classification algorithm, light intensity setup system propose variable resistor method which makes users more easy to control. Automatic light on-off system set a standard by measured illuminance data. Measured light-intensity through the Illuminance Detector are communicated with the signboard power controller with wireless communication, and it controls lighting system. In this paper, we evaluated the Energy-Efficient Automatic Power Controller of The Signboard using illuminance detector. Experimental results in lightless environment shows that the error rate is less than 3% by Accredited Testing Laboratories.

Interference Avoidance Technology in Cognitive Based MB-OFDM UWB System (인지 기반 MB-OFDM UWB 시스템에서의 간섭 회피 기술)

  • Sung, Tae-Kyung;Weon, Young-Su;Cho, Hyung-Rae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.6
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    • pp.677-687
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    • 2008
  • CR technology is an intelligent technology which can sense the spectrum environment an adaptively adjust the parameters for wireless transmission. In this paper, by using CR-UWB, the spectrum efficiency of the transmission channel is largely improved; Furthermore, the interference to other system can be effectively avoided. In this paper, we propose a solution on interference problem of UWB system using cognitive radio. We use interference temperature model of cognitive radio that has proposed by FCC for estimating interference signal. Calculating channel capacity of UWB system with interference temperature, we suggest how to solve interference problem. We have used genetic algorithm in cognitive engine's calculation precess. The proposed UWB System with cognitive radio shows very efficient in solving interference problem.

Multi-hop Relay System for Multicast and Broadcast Service over Mobile WiMAX (멀티캐스트와 브로드캐스트 서비스의 성능 향상을 위한 모바일 와이맥스 중계 시스템)

  • Cho, Chi-Hyun;Youn, Hee-Yong
    • Journal of KIISE:Information Networking
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    • v.35 no.3
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    • pp.227-234
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    • 2008
  • The development of wireless network technology allows high data rate seamless communication irrespective of the place and time in various emerging mobile service environment. Unlike wired networks, however, wireless networks utilize expensive limited bandwidth. MBS(Multicast Broadcast Service), which is supported by mobile WiMAX system based on IEEE802.16e, overcomes this problem using a shared downlink channel for efficiently supporting a number of users. However. the coverage and throughput of the system are significantly affected by the channel condition. In this paper we propose on MBS system employing Mobile Multi-Hop Relay(MMR) and adaptive modulation and coding(AMC) scheme. The result of NS-2 computer simulation shows that the throughput and transmission time are substantially improved by the proposed approach compared to the existing MBS system.

Design and Implementation of a Ubiquitous Health Care System based on Sensor Network (센서네트워크에 기반한 유비쿼터스 헬스케어 시스템의 설계 및 구현)

  • Kim, Jeong-Won
    • The Journal of the Korea Contents Association
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    • v.8 no.1
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    • pp.143-151
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    • 2008
  • In this paper, we have implemented a ubiquitous healthcare system that can measure and check human's health in anytime and anywhere. The implemented prototype are composed of both front-end and back-end. The front-end have several groups: environment sensor group such as temperature, humidity, photo, voice sensor, health sensor group such as blood pressure, heart beat, electrocardiogram, spo2 sensor, gateway for wired/wireless communication, and RFID reader to identify personal. The back-end has a serial forwarder to propagate measurment results, monitor program, and medical information server The implemented sensor node constructs a sensor network using the Zigbee protocol and is ported the tinyOS. The data gathering base node is linux-based terminal that can transfer a sensed medial data through wireless LAN. And, the medical information server stores the processed medical data and can promptly notify the urgent status to the connected medical team. Through our experiments, we've confirmed the possibility of ubiquitous healthcare system based on sensor network using the Zigbee.

Wired/Wireless Gateway System Supporting LAN-to-LAN VPN with Multi-Queuing Realtime Traffic Shaping (다중큐잉 실시간 트래픽쉐이핑을 적용한 네트워크간 VPN 지원 유무선공유기 시스템)

  • Yang, Seung Eui;Goh, Byung Oh;Choi, Jong-Kun;Jung, Hoe-kyung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.5
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    • pp.1097-1103
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    • 2015
  • In order to build network infrastructure to implement the aforementioned advantages enabling smart device users to work anywhere, professional support and expensive VPN devices are required. This is a barrier to supplying VPN devices to small and medium-sized institutes. To address this issue, this study aims to implement OpenVPN, OpenSSH and iproute based on the OpenWRT platform which is an embedded OS for open networks in affordable open wired/wireless gateway H/W platforms to support the inter-network VPN. In addition, the network environment can be maintained optimal by applying a "multi-queuing real-time traffic shaping technology" to VPN tunnels, although channel quality changes.

A Distributed Medium Access Control Protocol Based on Adaptive Collision Detection in Dense Wireless Local Area Networks (밀집 무선랜 환경에서 적응적 충돌 검출 기반의 분산 매체접속제어 프로토콜)

  • Choi, Hyun-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.12
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    • pp.2259-2266
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    • 2016
  • Recently dense wireless local area networks (WLANs) emerge as the number of WLAN cells and stations increases. In such dense WLAN environment, this paper proposes a new distributed medium access control (MAC) protocol. The proposed MAC protocol extends the previous CSMA with collision resolution (CSMA/CR) that uses a single collision detection (CD) phase and employs multiple CD phases to resolve more collisions. It checks the collision detection in each CD phase and stops the CD phase if consecutive non-detected CD phases occur more than the threshold. Therefore, the proposed protocol can control the number of CD phases adaptively according to the number of accessing stations and increase the probability of collision resolution while decreasing the packet overhead. The simulation results show that the proposed adaptive CSMA/CR protocol employs a variable number of CD phases according to the number of stations and achieves a greater throughput than the previous CSMA/CR protocol using the fixed number of CD phases.

Design and Implementation of SMS Application System with Wireless Internet Environment (무선인터넷환경과 연계한 SMS애플리케이션 시스템의 설계 및 구현)

  • Yang Hae-Sool;Hong Jung-Hun
    • The KIPS Transactions:PartD
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    • v.11D no.7 s.96
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    • pp.1507-1516
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    • 2004
  • Recently, the most remarkable word is 'ubiuuitous' in field of information and communication. Ubiquitous has a meaning 'exist everywhere' that means our daily life is connect as network. It means we can get the information which in need whenever and wherever with safety. We predict this word will be symbolical keyword which lead an information-oriented society including the internet a quite long it. It's already per-meate to us the Ubiquitous. It's taken by CCTV when we visit bank. It's made to us can know the fastest way the GPS system to be connected by an artificial satcllite on mobile, and many people use mobile and PDA for investment in stocks. Among them, it has begun to spread many mobile services to us. In this paper, it's the aim a creation of value added through an efficient mobile services to use wireless internet different with previous way, cutting down on expenses and business modeling.

Security Scheme for Prevent malicious Nodes in WiMAX Environment (노드간 에너지 소비를 효율적으로 분산시킨 PRML 메커니즘)

  • Jeong, Yoon-Su;Kim, Yong-Tae;Park, Nam-Kyu;Park, Gil-Cheol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.4
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    • pp.774-784
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    • 2009
  • A wireless sensor network consisting of a large number of nodes with limited battery power should minimize energy consumption at each node to prolong the network lifetime. To improve the sensitivity of wireless sensor networks, an efficient scheduling algorithm and energy management technology for minimizing the energy consumption at each node is desired. ill this paper, we propose energy-aware routing mechanism for maximum lifetime and to optimize the solution quality for sensor network maintenance and to relay node from its adjacent cluster heads according to the node"s residual energy and its distance to the base station. Proposed protocol may minimize the energy consumption at each node, thus prolong the lifetime of the system regardless of where the sink is located outside or inside the cluster. Simulation results of proposed scheme show that our mechanism balances the energy consumption well among all sensor nodes and achieves an obvious improvement on the network lifetime. To verify propriety using NS-2, proposed scheme constructs sensor networks adapt to current model and evaluate consumption of total energy, energy consumption of cluster head, average energy dissipation over varying network areas with HEED and LEACH-C.

Analysis for Protocol Layer Technical Requirements of Wireless Mesh Networks Optimization (무선 메쉬 네트워크의 최적화를 위한 프로토콜 계층별 기술적 요구사항에 관한 분석)

  • Lee, Soon-Sik;Yun, Sang-Man;Lee, Sang-Wook;Jeon, Seong-Geun;Lee, Woo-Jae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.1
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    • pp.77-88
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    • 2010
  • Wireless Mesh Networks are consist of mobility mesh clients and mesh routers. WMNs can communicate with heterogeneous networks such as IEEE 802.11, IEEE 802.15, IEEE 802.16 and sensor networks. WMNs which is based on ad hoc network are on research and developing to enhance WLANs, WPANs, or WMANs. WMNs can offer environment to serve human, service to person area, campus, and metro. But WMNs has many problems to solve about enhancing performance and generalization. Among them, Existing protocol layers has many problems enhancing to optimize WMNs. This document issues problems about WMNs in protocol layer and suggest the solutions. Also, suggests the requirements and the methods of QoS supporting issue.

Design and Implementation of sensor Network Based on UPnP Middlewere for Ubiquitous Healthcare System (U-헬스케어 시스템을 위한 UPnP기반센서 네트워크의 설계 및 구현)

  • Kang, Sung-In;Jean, Je-Hwan;Kim, Gwan-Hyung;Choi, Sung-Uk;Kim, Hae-Young;Oh, Am-Suk
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.4
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    • pp.797-804
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    • 2009
  • Recently, To provide various service for user, there are some trends to construct health care system using bio-sensors and wireless network technologies. Accordingly, An effective middleware is needed to manage and control the various bio-sensors. Also, it is important to extend network and interoperate the various application system in healthcare service. In this paper, we propose to be connected with network based on UPnP by design and implementation of UPnP-ZigBee bridge. The proposed UPnP-ZigBee bridge manage and control ZigBee sensor module effectively. we implemented and tested ECG, PPG, and environment sensor module based on ZigBee wireless network to apply in health care service.