4,399 research outputs found
Enhancing Received Signal Strength-Based Localization through Coverage Hole Detection and Recovery
In wireless sensor networks (WSNs), Radio Signal Strength Indicator (RSSI)-based localization techniques have been widely used in various applications, such as intrusion detection, battlefield surveillance, and animal monitoring. One fundamental performance measure in those applications is the sensing coverage of WSNs. Insufficient coverage will significantly reduce the effectiveness of the applications. However, most existing studies on coverage assume that the sensing range of a sensor node is a disk, and the disk coverage model is too simplistic for many localization techniques. Moreover, there are some localization techniques of WSNs whose coverage model is non-disk, such as RSSI-based localization techniques. In this paper, we focus on detecting and recovering coverage holes of WSNs to enhance RSSI-based localization techniques whose coverage model is an ellipse. We propose an algorithm inspired by Voronoi tessellation and Delaunay triangulation to detect and recover coverage holes. Simulation results show that our algorithm can recover all holes and can reach any set coverage rate, up to 100% coverage
Machine Learning in Wireless Sensor Networks: Algorithms, Strategies, and Applications
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
Thirty Years of Machine Learning: The Road to Pareto-Optimal Wireless Networks
Future wireless networks have a substantial potential in terms of supporting
a broad range of complex compelling applications both in military and civilian
fields, where the users are able to enjoy high-rate, low-latency, low-cost and
reliable information services. Achieving this ambitious goal requires new radio
techniques for adaptive learning and intelligent decision making because of the
complex heterogeneous nature of the network structures and wireless services.
Machine learning (ML) algorithms have great success in supporting big data
analytics, efficient parameter estimation and interactive decision making.
Hence, in this article, we review the thirty-year history of ML by elaborating
on supervised learning, unsupervised learning, reinforcement learning and deep
learning. Furthermore, we investigate their employment in the compelling
applications of wireless networks, including heterogeneous networks (HetNets),
cognitive radios (CR), Internet of things (IoT), machine to machine networks
(M2M), and so on. This article aims for assisting the readers in clarifying the
motivation and methodology of the various ML algorithms, so as to invoke them
for hitherto unexplored services as well as scenarios of future wireless
networks.Comment: 46 pages, 22 fig
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Automatic triangulation positioning system for wide area coverage from a fixed sensors network
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonIn a wide area that many Transmitters (TRs) operate, systems of Fixed Sensors (FS) might be used in order to detect them and find TRs position. The detection and the accurate location of a new TR entering in the area frequently can be missed if the system fails to triangulate accurately the relative readings and analyze the changes in the received data. Additionally, there are cases that a Triangulation Station Network (TSN) can detect the heading as well as the transmitter’s position wrong. This thesis presents the design of a Sensors Network (FSN) system which is able to interact with a user, and exploit the relative data of the Sensors (SRs) in real time. The system performs localization with triangulation and the SRs are detect only TRs bearing data (range free). System design and algorithms are also explained. Efficient algorithms were elaborated and the outcomes of their implementation were calculated. The system design targets to reduce system errors and increase the accuracy and the speed of detection. Synchronously and through interaction with the user and changes of relative settings and parameters will be able to offer the user accurate results on localization of TRs in the area minimizing false readings and False Triangulations (FTRNs). The system also enables the user to apply optimization techniques in order to increase the system detection rate and performance and keep the surveillance in the Field of Interest (FoI) on a high level. The optimization methodology applied for the system proves that the FSN system is able to operate with a high performance even when saturation phenomena appear. The unique outcome of the research conducted, is that this thesis paves the way to enhance the localization via Triangulation for a network of Fixed Sensors with known position. The value of this thesis is that the FSN system performs bearing only detection (Range free) with a certain accuracy and the Area of Interest (AOI) is covered efficiently
Synergizing Airborne Non-Terrestrial Networks and Reconfigurable Intelligent Surfaces-Aided 6G IoT
On the one hand, Reconfigurable Intelligent Surfaces (RISs) emerge as a
promising solution to meet the demand for higher data rates, improved coverage,
and efficient spectrum utilization. On the other hand, Non-Terrestrial Networks
(NTNs) offer unprecedented possibilities for global connectivity. Moreover, the
NTN can also support the upsurge in the number of Internet of Things (IoT)
devices by providing reliable and ubiquitous connectivity. Although NTNs have
shown promising results, there are several challenges associated with their
usage, such as signal propagation delays, interference, security, etc. In this
article, we have discussed the possibilities of integrating RIS with an NTN
platform to overcome the issues associated with NTN. Furthermore, through
experimental validation, we have demonstrated that the RIS-assisted NTN can
play a pivotal role in improving the performance of the entire communication
system.Comment: 15 pages, 5 figure
A Wearable Fall Detection System based on LoRa LPWAN Technology
Several technological solutions now available in the
market offer the possibility of increasing the independent life
of people who by age or pathologies otherwise need assistance.
In particular, internet-connected wearable solutions are of considerable interest, as they allow continuous monitoring of the
user. However, their use poses different challenges, from the real
usability of a device that must still be worn to the performance
achievable in terms of radio connectivity and battery life. The
acceptability of a technology solution, by a user who would still
benefit from its use, is in fact often conditioned by practical
problems that impact the person’s normal lifestyle. The technological choices adopted in fact strongly determine the success
of the proposed solution, as they may imply limitations both
to the person who uses it and to the achievable performance.
In this document, targeting the case of a fall detection sensor
based on a pair of sensorized shoes, the effectiveness of a real
implementation of an Internet of Things technology is examined.
It is shown how alarming events, generated in a metropolitan
context, are effectively sent to a supervision system through
Low Power Wide Area Network technology without the need
for a portable gateway. The experimental results demonstrate
the effectiveness of the chosen technology, which allows the user
to take advantage of the support of a wearable sensor without
being forced to substantially change his lifestyle
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Coverage Area of a Localization Fixed Sensors Network System with the process of Triangulation
Copyright © 2021 The Authors. This paper presents a novel work on localization of transmitters using triangulation with sensors at fixed positions. This is achieved when three or more sensors cover the whole area, a factor which enables the system to perform localization via triangulation. The network needs to keep a high detection rate which, in most cases, is achieved by adequate sensor coverage. Various tests using various grids of sensors have been carried out to investigate the way the system operates in different cases using a lot of transmitters. Detection complexity is tackled by finding the optimal detecting sensor radius in order the network to continue operate normally. The coverage quality changes in the area of interest and the network is able to detect new transmitters that might enter it's area. It is also shown that as the number of transmitters increases the network keeps its high performance by using additional groups of sensors in a sub-region area of that of interest. This way, even when the network is saturated by many transmitters in one region, new transmitters can still be detected
A novel trigger-based method for hydrothermal vents prospecting using an autonomous underwater robot
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Autonomous Robots 29 (2010): 67-83, doi:10.1007/s10514-010-9187-y.In this paper we address the problem of localizing active hydrothermal vents on the
seafloor using an Autonomous Underwater Vehicle (AUV). The plumes emitted by hydrothermal
vents are the result of thermal and chemical inputs from submarine hot spring systems into the
overlying ocean. The Woods Hole Oceanographic Institution's Autonomous Benthic Explorer
(ABE) AUV has successfully localized previously undiscovered hydrothermal vent fields in
several recent vent prospecting expeditions. These expeditions utilized the AUV for a three-stage,
nested survey strategy approach (German et al., 2008). Each stage consists of a survey flown at
successively deeper depths through easier to detect but spatially more constrained vent fluids.
Ideally this sequence of surveys culminates in photographic evidence of the vent fields themselves.
In this work we introduce a new adaptive strategy for an AUV's movement during the first,
highest-altitude survey: the AUV initially moves along pre-designed tracklines but certain
conditions can trigger an adaptive movement that is likely to acquire additional high value data for
vent localization. The trigger threshold is changed during the mission, adapting the method to the
different survey profiles the robot may find. The proposed algorithm is vetted on data from
previous ABE missions and measures of efficiency presented
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