5,744 research outputs found

    An Optimized In-Network Aggregation Scheme for Data Collection in Periodic Sensor Networks

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    International audienceIn-network data aggregation is considered an effective technique for conserving energy communication in wireless sensor networks. It consists in eliminating the inherent redundancy in raw data collected from the sensor nodes. Prior works on data aggregation protocols have focused on the measurement data redundancy. In this paper, our goal in addition of reducing measures redundancy is to identify near duplicate nodes that generate similar data sets. We consider a tree based bi-level periodic data aggregation approach implemented on the source node and on the aggregator levels. We investigate the problem of finding all pairs of nodes generating similar data sets such that similarity between each pair of sets is above a threshold t. We propose a new frequency filtering approach and several optimizations using sets similarity functions to solve this problem. To evaluate the performance of the proposed filtering method, experiments on real sensor data have been conducted. The obtained results show that our approach offers significant data reduction by eliminating in network redundancy and out-performs existing filtering techniques

    Compression-based Data Reduction Technique for IoT Sensor Networks

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    في شبكات أجهزة استشعار إنترنت الأشياء ، يعد توفير الطاقة أمرًا مهمًا جدًا نظرًا لأن عقد أجهزة استشعار إنترنت الأشياء تعمل ببطاريتها المحدودة. يعد نقل البيانات مكلفًا للغاية في عقد أجهزة استشعار إنترنت الأشياء ويهدر معظم الطاقة ، في حين أن استهلاك الطاقة أقل بكثير بالنسبة لمعالجة البيانات. هناك العديد من التقنيات والمفاهيم التي تعنى بتوفير الطاقة ، وهي مخصصة في الغالب لتقليل نقل البيانات. لذلك ، يمكننا الحفاظ على كمية كبيرة من الطاقة مع تقليل عمليات نقل البيانات في شبكات مستشعر إنترنت الأشياء. في هذا البحث ، اقترحنا طريقة تقليل البيانات القائمة على الضغط (CBDR) والتي تعمل في مستوى عقد أجهزة استشعار إنترنت الأشياء. يتضمن CBDR مرحلتين للضغط ، مرحلة التكميم باستخدام طريقة SAX والتي تقلل النطاق الديناميكي لقراءات بيانات المستشعر ، بعد ذلك ضغط LZW بدون خسارة لضغط مخرجات المرحلة الاولى. يؤدي تكميم قراءات البيانات لعقد المستشعر إلى حجم ابجدية الـ SAX إلى تقليل القراءات ، مع الاستفادة من أفضل أحجام الضغط ، مما يؤدي إلى تحقيق ضغط أكبر في LZW. نقترح أيضًا تحسينًا آخر لطريقة CBDR وهو إضافة ناقل حركة ديناميكي (DT-CBDR) لتقليل إجمالي عدد البيانات المرسلة إلى البوابة والمعالجة المطلوبة. يتم استخدام محاكي OMNeT ++ جنبًا إلى جنب مع البيانات الحسية الحقيقية التي تم جمعها في Intel Lab لإظهار أداء الطريقة المقترحة. توضح تجارب المحاكاة أن تقنية CBDR المقترحة تقدم أداء أفضل من التقنيات الأخرى في الأدبياتEnergy savings are very common in IoT sensor networks because IoT sensor nodes operate with their own limited battery. The data transmission in the IoT sensor nodes is very costly and consume much of the energy while the energy usage for data processing is considerably lower. There are several energy-saving strategies and principles, mainly dedicated to reducing the transmission of data. Therefore, with minimizing data transfers in IoT sensor networks, can conserve a considerable amount of energy. In this research, a Compression-Based Data Reduction (CBDR) technique was suggested which works in the level of IoT sensor nodes. The CBDR includes two stages of compression, a lossy SAX Quantization stage which reduces the dynamic range of the sensor data readings, after which a lossless LZW compression to compress the loss quantization output. Quantizing the sensor node data readings down to the alphabet size of SAX results in lowering, to the advantage of the best compression sizes, which contributes to greater compression from the LZW end of things. Also, another improvement was suggested to the CBDR technique which is to add a Dynamic Transmission (DT-CBDR) to decrease both the total number of data sent to the gateway and the processing required. OMNeT++ simulator along with real sensory data gathered at Intel Lab is used to show the performance of the proposed technique. The simulation experiments illustrate that the proposed CBDR technique provides better performance than the other techniques in the literature

    Frequency Filtering Approach for Data Aggregation in Periodic Sensor Networks

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    International audienceThis paper presents an energy-efficient technique for data aggregation in periodic sensor networks. We investigate the problem of finding all pairs of nodes generating similar data sets such that similarity between each pair of sets is above a threshold t. We provide a frequency filtering approach to solve this problem. Our experiments demonstrate that our algorithm outperforms existing prefix filtering methods in reducing energy consumption

    Machine Learning in Wireless Sensor Networks: Algorithms, Strategies, and Applications

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    Wireless sensor networks monitor dynamic environments that change rapidly over time. This dynamic behavior is either caused by external factors or initiated by the system designers themselves. To adapt to such conditions, sensor networks often adopt machine learning techniques to eliminate the need for unnecessary redesign. Machine learning also inspires many practical solutions that maximize resource utilization and prolong the lifespan of the network. In this paper, we present an extensive literature review over the period 2002-2013 of machine learning methods that were used to address common issues in wireless sensor networks (WSNs). The advantages and disadvantages of each proposed algorithm are evaluated against the corresponding problem. We also provide a comparative guide to aid WSN designers in developing suitable machine learning solutions for their specific application challenges.Comment: Accepted for publication in IEEE Communications Surveys and Tutorial

    Data redundancy reduction for energy-efficiency in wireless sensor networks: a comprehensive review

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    Wireless Sensor Networks (WSNs) play a significant role in providing an extraordinary infrastructure for monitoring environmental variations such as climate change, volcanoes, and other natural disasters. In a hostile environment, sensors' energy is one of the crucial concerns in collecting and analyzing accurate data. However, various environmental conditions, short-distance adjacent devices, and extreme usage of resources, i.e., battery power in WSNs, lead to a high possibility of redundant data. Accordingly, the reduction in redundant data is required for both resources and accurate information. In this context, this paper presents a comprehensive review of the existing energy-efficient data redundancy reduction schemes with their benefits and limitations for WSNs. The entire concept of data redundancy reduction is classified into three levels, which are node, cluster head, and sink. Additionally, this paper highlights existing key issues and challenges and suggested future work in reducing data redundancy for future research

    Topology control and data handling in wireless sensor networks

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    Our work in this thesis have provided two distinctive contributions to WSNs in the areas of data handling and topology control. In the area of data handling, we have demonstrated a solution to improve the power efficiency whilst preserving the important data features by data compression and the use of an adaptive sampling strategy, which are applicable to the specific application for oceanography monitoring required by the SECOAS project. Our work on oceanographic data analysis is important for the understanding of the data we are dealing with, such that suitable strategies can be deployed and system performance can be analysed. The Basic Adaptive Sampling Scheduler (BASS) algorithm uses the statistics of the data to adjust the sampling behaviour in a sensor node according to the environment in order to conserve energy and minimise detection delay. The motivation of topology control (TC) is to maintain the connectivity of the network, to reduce node degree to ease congestion in a collision-based medium access scheme; and to reduce power consumption in the sensor nodes. We have developed an algorithm Subgraph Topology Control (STC) that is distributed and does not require additional equipment to be implemented on the SECOAS nodes. STC uses a metric called subgraph number, which measures the 2-hops connectivity in the neighbourhood of a node. It is found that STC consistently forms topologies that have lower node degrees and higher probabilities of connectivity, as compared to k-Neighbours, an alternative algorithm that does not rely on special hardware on sensor node. Moreover, STC also gives better results in terms of the minimum degree in the network, which implies that the network structure is more robust to a single point of failure. As STC is an iterative algorithm, it is very scalable and adaptive and is well suited for the SECOAS applications
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