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Search Results: 1 - 10 of 15023 matches for " Wireless Sensor Networks "
All listed articles are free for downloading (OA Articles)
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Design of Orthogonal UWB Pulse Waveform for Wireless Multi-Sensor Applications  [PDF]
Hannu Olkkonen, Juuso T. Olkkonen
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.211102
Abstract: In this work we propose an orthogonal pulse waveform for wireless ultra wideband (UWB) transmission. The design is based on an ideal low-pass prototype filter having a windowed sinc impulse response. The frequency response of the prototype filter is transferred to the high frequency region using a specific sign modulator. The UWB pulse waveform comprises of the weighted summation of the left singular vectors of the impulse response matrix. The power spectral density of the pulse waveform fulfils the FCC constraint (allowed frequency band 3.1-10.6 GHz) for unlicensed UWB transmission. Applications of the UWB pulse waveform in multi-channel wireless sensor networks are considered.
On Energy-Efficient Node Deployment in Wireless Sensor Networks  [PDF]
Hui WANG, KeZhong LU, XiaoHui LIN
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2008, DOI: 10.4236/ijcns.2008.13029
Abstract: In wireless sensor networks, sensor nodes collect local data and transfer to the base station often relayed by other nodes. If deploying sensor nodes evenly, sensor nodes nearer to the base station will consume more energy and use up their energy faster that reduces system lifetime. By analyzing energy consumption, a density formula of deploying nodes is proposed. The ratio of whole energy of sensor nodes to energy consumption speed of sensor nodes in every area can get consistent if deploying nodes by the density formula, therefore system lifetime is prolonged. Analysis and simulation results show that when communication dominates whole energy consumption and the monitored region is big compared with radio range of sensor node, system lifetime under this scheme can be 3R/(2t) times of that under deploying nodes evenly, where R is radius of the monitored region and t is radio range of sensor node.
Wireless Bioradar Sensor Networks for Speech Detection and Communication  [PDF]
Ying Tian, Sheng Li, Jianqi Wang
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.55B008
Abstract: Wireless multimedia sensor networks (WMSN) are emerging to serve for the collection of acoustic and image information. In the WMSN, the microphone is usually employed to function as sensor nodes for the acquisition of acoustic data. However, those microphone sensors are needed to be placed close with sound source and cannot detect sound signal through certain obstacles. To overcome the shortcomings of microphone sensor, we develop a new type of bioradar sensor to achieve non-contact speech detection and investigate theoretically the mechanism of bioradar for speech detection. Results show that the system can successfully detect speech at some distance and even through non-metallic objects with certain thickness. In addition, in order to suppress the noise and improve the quality of the detected speech, we use spectral subtraction and Wiener filtering algorithm respectively to enhance the bioradar speech and evaluate the performance of the two methods using spectrogram.
Investigation and Implementation of a PIC-Based Sensor Node for Wireless Sensor Networks  [PDF]
?mer ?zcan, Mesut Gündüz
Journal of Computer and Communications (JCC) , 2014, DOI: 10.4236/jcc.2014.24013
Abstract:

The basic component of wireless sensor networks is sensor node, and it is one of the most investigated complex issues in wireless sensor networks. Within this investigation concept, one of the major topics focused on wireless sensor networks is designing sensor node equipment. In this study, a new wireless sensor node design was proposed. In this design, a low-power PIC and a low-power transceiver-receiver device were used. In order to connect various sensors to the node, an expansion slot was designed. The software that runs on the microcontroller was written in the PIC-C language, and it could be adapted for different routing algorithms and sensor types. So this paper presents an alternative low cost and low powered sensor node design and implementation for usage of the researchers and practitioners.

A Comparative Study of Medium Access Control Protocols for Wireless Sensor Networks  [PDF]
Meghan GUNN, Simon G. M. KOO
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.28080
Abstract: One of the major constraints in wireless sensor networks (WSNs) is power consumption. In recent years, a lot of efforts have been put into the design of medium access control (MAC) protocols for WSN, in order to reduce energy consumption and enhance the network’s lifetime. In this paper, we surveyed some MAC protocols for WSN and compared their design tradeoffs. The goal is to provide a foundation for future MAC design, and to identify important design issues that allow us to improve the overall performances.
A New Scheduling Algorithm for Reducing Data Aggregation Latency in Wireless Sensor Networks  [PDF]
Meirui Ren, Longjiang Guo, Jinbao Li
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.38091
Abstract: Existing works on data aggregation in wireless sensor networks (WSNs) usually use a single channel which results in a long latency due to high interference, especially in high-density networks. Therefore, data aggre- gation is a fundamental yet time-consuming task in WSNs. We present an improved algorithm to reduce data aggregation latency. Our algorithm has a latency bound of 16R + Δ – 11, where Δ is the maximum degree and R is the network radius. We prove that our algorithm has smaller latency than the algorithm in [1]. The simulation results show that our algorithm has much better performance in practice than previous works.
Design of Building Monitoring Systems Based on Wireless Sensor Networks  [PDF]
Qifen Dong, Li Yu, Huanjia Lu, Zhen Hong, Yourong Chen
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.29085
Abstract: Wireless Sensor Network provides a potential technique for monitoring the indoor environment. This paper presents a Building Monitoring system based on Wireless Sensor Networks. A clustering-based network specified for building monitoring is proposed, which is inspired by LEACH (Low Energy Adaptive Cluster Hierarchy) method. Further, two key ideas are used to implement the clustering-based network. First, the configuration module of building management software is used to conduct all nodes in a room forming a local cluster. This cluster formation method does not consume node energy. Second, because cluster-heads cannot directly transmit packets to the sink node due to limited wireless communication range, the cluster-head communications are represented by a multi-hop tree rooted at the sink node. The experiment has been made to demonstrate the feasibility of the proposed results.
Compressing Information of Target Tracking in Wireless Sensor Networks  [PDF]
Jianzhong Li, Qianqian Ren
Wireless Sensor Network (WSN) , 2011, DOI: 10.4236/wsn.2011.32008
Abstract: Target tracking is a well studied topic in wireless sensor networks. It is a procedure that nodes in the network collaborate in detecting targets and transmitting their information to the base-station continuously, which leads to data implosion and redundancy. To reduce traffic load of the network, a data compressing based target tracking protocol is proposed in this work. It first incorporates a clustering based data gather method to group sensor nodes into clusters. Then a novel threshold technique with bounded error is proposed to exploit the spatial correlation of sensed data and compress the data in the same cluster. Finally, the compact data presentations are transmitted to the base-station for targets localization. We evaluate our approach with a comprehensive set of simulations. It can be concluded that the proposed method yields excellent performance in energy savings and tracking quality.
Minimization of Collision in Energy Constrained Wireless Sensor Network  [PDF]
Moses Nesa SUDHA, Muniappan Lakshapalam VALARMATHI, George RAJSEKAR, Michael Kurien MATHEW, Nagarajan DINESHRAJ, Sivasankaran RAJBARATH
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.14043
Abstract: Wireless Sensor Networks (WSNs) are one of the fastest growing and emerging technologies in the field of Wireless Networking today. The applications of WSNs are extensively spread over areas like Military, En-vironment, Health Care, Communication and many more. These networks are powered by batteries and hence energy optimization is a major concern. One of the factors that reduce the energy efficiency of the WSN is collision which occurs due to the high density of data packets in a typical communication channel. This paper aims at minimizing the effects of congestion leading to collision in the network by proposing an effective algorithm. This can be done by optimizing the size of the contention window by introducing pa-rameters like source count and α. If the contention window of a node is low, it results in collision. If the size of the contention window of a node is high then it results in a medium access delay. Thus minimizing colli-sion and medium access delay of data packets conserve energy.
Wireless Sensor Network Management and Functionality: An Overview  [PDF]
Dimitrios GEORGOULAS, Keith BLOW
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.14032
Abstract: Sensor networks are dense wireless networks of small, low-cost sensors, which collect and disseminate en-vironmental data. Wireless sensor networks facilitate monitoring and controlling of physical environments from remote locations with better accuracy. They have applications in a variety of fields such as environ-mental monitoring; military purposes and gathering sensing information in inhospitable locations. Sensor nodes have various energy and computational constraints because of their inexpensive nature and adhoc method of deployment. Considerable research has been focused at overcoming these deficiencies through more energy efficient routing, localization algorithms and system design. Our survey presents the funda-mentals of wireless sensor network, thus providing the necessary background required for understanding the organization, functionality and limitations of those networks. The middleware solution is also investigated through a critical presentation and analysis of some of the most well established approaches.
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