• Title/Summary/Keyword: wsn

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Performance Evaluation of De/Modulations for ULP Communications for WPAN Systems (WPAN 시스템에서 초저전력 통신을 위한 변/복조 기술 성능 평가)

  • Kim, Yongok;Jang, Youngrok;Choi, Sooyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.1
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    • pp.80-82
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    • 2016
  • In this letter, we evaluate the performances of both GOOK and GFSK de/modulation techniques which are candidates for ULP communications in WPAN systems. For the performance evaluation, we define the system model for each of GOOK and GFSK de/modulations and perform computer simulations based on the proposed models. From the computer simulations, we show that GOOK de/modulation technique has 15 dB out-of-band emission gain and is robust over frequency offsets in terms of BER compared to GFSK de/modulation technique.

Clustering Algorithm Considering Sensor Node Distribution in Wireless Sensor Networks

  • Yu, Boseon;Choi, Wonik;Lee, Taikjin;Kim, Hyunduk
    • Journal of Information Processing Systems
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    • v.14 no.4
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    • pp.926-940
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    • 2018
  • In clustering-based approaches, cluster heads closer to the sink are usually burdened with much more relay traffic and thus, tend to die early. To address this problem, distance-aware clustering approaches, such as energy-efficient unequal clustering (EEUC), that adjust the cluster size according to the distance between the sink and each cluster head have been proposed. However, the network lifetime of such approaches is highly dependent on the distribution of the sensor nodes, because, in randomly distributed sensor networks, the approaches do not guarantee that the cluster energy consumption will be proportional to the cluster size. To address this problem, we propose a novel approach called CACD (Clustering Algorithm Considering node Distribution), which is not only distance-aware but also node density-aware approach. In CACD, clusters are allowed to have limited member nodes, which are determined by the distance between the sink and the cluster head. Simulation results show that CACD is 20%-50% more energy-efficient than previous work under various operational conditions considering the network lifetime.

Landslide Detection using Wireless Sensor Networks (사면방재를 위한 무선센서 네트워크 기술연구)

  • Kim, Hyung-Woo;Lee, Bum-Gyo
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.369-372
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    • 2008
  • Recently, landslides have frequently occurred on natural slopes during periods of intense rainfall. With a rapidly increasing population on or near steep terrain in Korea, landslides have become one of the most significant natural hazards. Thus, it is necessary to protect people from landslides and to minimize the damage of houses, roads and other facilities. To accomplish this goal, many landslide prediction methods have been developed in the world. In this study, a simple landslide prediction system that enables people to escape the endangered area is introduced. The system is focused to debris flows which happen frequently during periods of intense rainfall. The system is based on the wireless sensor network (WSN) that is composed of sensor nodes, gateway, and server system. Sensor nodes comprising a sensing part and a communication part are developed to detect ground movement. Sensing part is designed to measure inclination angle and acceleration accurately, and communication part is deployed with Bluetooth (IEEE 802.15.1) module to transmit the data to the gateway. To verify the feasibility of this landslide prediction system, a series of experimental studies was performed at a small-scale earth slope equipped with an artificial rainfall dropping device. It is found that sensing nodes installed at slope can detect the ground motion when the slope starts to move. It is expected that the landslide prediction system by wireless senor network can provide early warnings when landslides such as debris flow occurs.

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Efficient Data Storage & Query Processing Methods in Military Ubiquitous Sensor Networks (군 USN 환경에서 효율적인 데이터 저장 및 질의 처리 방법 연구)

  • Kwon, Young-Mo;Choi, Hyun-Sik;Chung, Yon-Dohn
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.5
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    • pp.875-885
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    • 2010
  • Recently, the role of Ubiquitous Sensor Network(USN) has been considered to be essential for supporting the near future Network Centric Warfare(NCW) and Tactical Information Communication Network(TICN). In this paper, we explore a set of data storage methods(external storage, local storage and data storage) and query processing methods in WSN. In particular, we focus on analyzing a novel data structure for supporting the local storage method, named the partial ordered tree(POT). The main idea behind POT is that sensor readings are usually correlated with the physical spatial domain. With the help of POT, only a small portion of sensor nodes participate in query processing tasks, and thus network lifetime is greatly increased. Through a series of simulation experiments, we demonstrate that the POT based local storage method clearly outperforms the existing data storage methods in terms of the energy-efficiency, which directly affects the network lifetime, for processing exact match queries, range queries and top-k queries.

Cooperative Data Forwarding in Border Surveillance Networks (국경감시망에서의 협력적 데이터 포워딩 방법)

  • Oh, Se-Min;Kim, Dong-Wan;An, Sun-Shin;Boudriga, Noureddine
    • Annual Conference of KIPS
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    • 2014.11a
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    • pp.196-198
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    • 2014
  • Wireless Sensor Networks(WSN) 기반의 Border Surveillance Networks(BSN)는 다양한 제한조건을 동반하며 침입 혹은 환경 등을 감시함을 목적으로 하고 있기 때문에 이벤트 발생시 신뢰적인 데이터 전송은 매우 중요한 부분을 차치하게 된다. 본 논문에서 적용한 대표적인 요구기반 라우팅 방법인 Ad hoc On-demand Distance Vector Routing(AODV)는 BSN 에 적용하였을 경우 홉 수(Hop Count)를 메트릭으로 최적의 경로를 계산하고 선택하여 Uni-Path 로 데이터를 전송하게 된다. 이때 AODV 는 Uni-path 로 데이터 전송을 진행하게 되며 링크의 단절이 빈번히 발생하는 BSN 의 환경적 요인으로 데이터 전송의 신뢰성이 감소하게 될 것이며 이는 비효과적인 데이터 전송을 야기하게 된다. 따라서 본 논문에서는 Multi-path 개념을 도입하여 데이터 전송 시 링크단절에 의해 발생하는 시간의 지연을 줄이고 더욱 신뢰성 있게 데이터를 전송할 수 있는 방법을 제안한다. 제안하는 방법은 송, 수신하는 두 노드의 전송범위에 공통으로 속한 노드들이 전송되는 데이터를 중복 전송하게 된다. 그리하여 링크의 단절이 일어날 경우 발생하는 경로 재 탐색 및 경로복구의 발생 빈도를 줄이고 동시에 데이터 전송률을 증가시켜 신뢰적인 데이터 전송을 하게 된다.

Design, Analysis and Evaluation of A New Energy Conserving MAC Protocol for Wireless Sensor Networks

  • Lim, Sangsoon;Kang, Young-Myoung;Jeong, Jiwoong;Kim, Chong-Kwon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.12
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    • pp.3046-3060
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    • 2012
  • Low power listening (LPL) MAC protocols based on duty-cycling mechanism have been studied extensively to achieve ultra low energy consumption in wireless sensor networks (WSNs). Especially, recent ACK-based LPL schemes such as X-MAC employ strobe preambles and an early ACK, and show fair performances in communications and energy efficiencies. However, the state-of-the-art ACK-based LPL scheme still suffers from collision problems due to the protocol incompleteness. These collision effects are not trivial and make WSNs unstable, aggravate energy consumptions. In this paper, we propose two novel schemes; (i) ${\tau}$-duration CCA to mitigate the collision problem in ACK-based LPL MAC protocols. (ii) Short Preamble Counter (SPC) to conserve more energy by reducing unnecessary overhearing. We demonstrate the performance improvement of our scheme via a mathematical analysis and real-time experiments. Both analysis and experimental results confirm that our proposed scheme saves energy by up to 36% compared to the naive ACK-based LPL MAC protocol thanks to ${\tau}$-duration CCA and SPC.

A Lightweight Authentication and Key Agreement Protocol in Wireless Sensor Networks (무선센서 네트워크에서 경량화된 인증과 키 동의 프로토콜)

  • Yoon, Sin-Sook;Ha, Jae-Cheol
    • Journal of Internet Computing and Services
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    • v.10 no.2
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    • pp.41-51
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    • 2009
  • Recently, there are many researches on security to remove vulnerability which is caused by wireless communication in wireless sensor networks. To guarantee secure communication, we should basically provide key management for each node, mutual authentication and key agreement protocol between two nodes. Although many protocols are presented to supply these security services, some of them require plentiful storage memory, powerful computation and communication capacity. In this paper, we propose a lightweight and efficient authentication and key agreement protocol between two sensor nodes, which is an enhanced version of Juang's scheme. In Juang's protocol, sensor node's information used to share a secret key should be transmitted to registration center via a base station. On the contrary, since node's information in our protocol is transmitted up to only base station, the proposed scheme can decrease computation and communication cost for establishing the shared key between two nodes.

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A Study on the Characteristic of Energy Harvesting Mechanism for Batteryless Wireless Switch (배터리없는 무선 스위치를 위한 에너지 하베스팅 메커니즘의 특성 연구)

  • Choi, Yeon-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.5
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    • pp.3114-3120
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    • 2014
  • Wireless emergency call switch used in industry, the most important thing is the sustainable power supply. This paper describes the development and performance test results of a compact electromagnetic energy harvesting mechanism for batteryless wireless switch. This paper summarizes proposed structure design and magnetic field analysis results of the mechanism to generate an induced electromotive force using 2mm stroke of a single push action. This analysis results show the power output of the proposed mechanism up to VDC $4.5V{\pm}25%$ and it can hold up to 65ms of the power generation with greater than 2.5V.

A Proposal of Time Synchronization amongst Wireless Sensors for Ship Diagnosis and Maintenance Supporting (선박의 진단 및 정비를 위해 사용되는 무선 센서 간 효율적인 시간동기 알고리즘 제안)

  • Kim, Byoung-Kug
    • Journal of Advanced Navigation Technology
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    • v.24 no.4
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    • pp.267-272
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    • 2020
  • In order to monitor in large area of a ship without any concerns of spacial environments, there can be the use of many sensors that support wireless network technologies. Through the deployment of the wireless sensors and their autonomous network formations, the status of a ship can be easily monitored in real time. Moreover, if all the sensors are timely synchronized with each other, the locations and the moving directions of certain events can be estimated. Thus, the time synchronization amongst wireless sensors are crucial. In this paper, we propose an algorithm which supports reduced message transmissions between the sensors for synchronization.

A Survey on Asynchronous Quorum-Based Power Saving Protocols in Multi-Hop Networks

  • Imani, Mehdi;Joudaki, Majid;Arabnia, Hamid R.;Mazhari, Niloofar
    • Journal of Information Processing Systems
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    • v.13 no.6
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    • pp.1436-1458
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    • 2017
  • Quorum-based algorithms are widely used for solving several problems in mobile ad hoc networks (MANET) and wireless sensor networks (WSN). Several quorum-based protocols are proposed for multi-hop ad hoc networks that each one has its pros and cons. Quorum-based protocol (QEC or QPS) is the first study in the asynchronous sleep scheduling protocols. At the time, most of the proposed protocols were non-adaptive ones. But nowadays, adaptive quorum-based protocols have gained increasing attention, because we need protocols which can change their quorum size adaptively with network conditions. In this paper, we first introduce the most popular quorum systems and explain quorum system properties and its performance criteria. Then, we present a comparative and comprehensive survey of the non-adaptive and adaptive quorum-based protocols which are subsequently discussed in depth. We also present the comparison of different quorum systems in terms of the expected quorum overlap size (EQOS) and active ratio. Finally, we summarize the pros and cons of current adaptive and non-adaptive quorum-based protocols.