A Performance Evaluation of the Coverage Configuration Protocol Under Location Errors, Irregular Sensing Patterns, and a Noisy Channel

2012 ◽  
Vol 8 (3) ◽  
pp. 28-41 ◽  
Author(s):  
Amine Dhraief ◽  
Imen Mahjri ◽  
Abdelfettah Belghith
Keyword(s):  
Area Coverage ◽  
Accurate Information ◽  
Noisy Channel ◽  
Coverage Problem ◽  
Packet Losses ◽  
Coverage Ratio ◽  
Sensing Coverage ◽  
Location Errors ◽  
Key Issues ◽  
The Impact

Area coverage problem is one of the key issues to prolong a wireless sensor network lifetime. It is based on selecting as few active nodes as possible from all deployed nodes while maintaining sufficient sensing coverage of the monitored region. Several area coverage protocols have been proposed, most of them assume the availability of accurate information about node locations and sensing ranges. Relaxing these conservative assumptions might impact the performance of area coverage protocols. In this paper, the authors study the impact of location errors, irregular sensing ranges and packet losses on the coverage configuration protocol. They focus more precisely on their impact on the number of selected active nodes, the coverage ratio and the total consumed energy.

scholarly journals A Novel Bi-Tuning SSO Algorithm for Optimizing the Budget-Limited Sensing Coverage Problem in Wireless Sensor Networks

2021 ◽  
Vol 11 (21) ◽  
pp. 10197
Author(s):  
Wenbo Zhu ◽  
Chia-Ling Huang ◽  
Wei-Chang Yeh ◽  
Yunzhi Jiang ◽  
Shi-Yi Tan
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Smart Grids ◽  
Wireless Sensor ◽  
Coverage Problem ◽  
Swarm Optimization ◽  
Coverage Ratio ◽  
Sensing Coverage ◽  
Limited Sensing ◽  
Novel Concept

The wireless sensor network (WSN) plays an essential role in various practical smart applications, e.g., smart grids, smart factories, Internet of Things, and smart homes, etc. WSNs are comprised and embedded wireless smart sensors. With advanced developments in wireless sensor networks research, sensors have been rapidly used in various fields. In the meantime, the WSN performance depends on the coverage ratio of the sensors being used. However, the coverage of sensors generally relates to their cost, which usually has a limit. Hence, a new bi-tuning simplified swarm optimization (SSO) is proposed that is based on the SSO to solve such a budget-limited WSN sensing coverage problem to maximize the number of coverage areas to improve the performance of WSNs. The proposed bi-tuning SSO enhances SSO by integrating the novel concept to tune both the SSO parameters and SSO update mechanism simultaneously. The performance and applicability of the proposed bi-tuning SSO using seven different parameter settings are demonstrated through an experiment involving nine WSN tests ranging from 20, 100, to 300 sensors. The proposed bi-tuning SSO outperforms two state-of-the-art algorithms: genetic algorithm (GA) and particle swarm optimization (PSO), and can efficiently accomplish the goals of this work.

A Performance Evaluation of the Coverage Configuration Protocol and its Applicability to Precision Agriculture

2014 ◽  
pp. 107-122
Author(s):  
Amine Dhraief ◽  
Imen Mahjri ◽  
Abdelfettah Belghith
Keyword(s):  
Precision Agriculture ◽  
Energy Supply ◽  
Urban Environments ◽  
Wireless Sensor ◽  
Packet Losses ◽  
Active Sensors ◽  
Sensing Coverage ◽  
Rural And Urban ◽  
Precise Knowledge ◽  
The Impact

Wireless Sensor Networks (WSNs) have recently emerged as a prominent technology for lots of civilian and military applications in both rural and urban environments. Area coverage configuration is an efficient method to alleviate the nodes' limited energy supply in high density WSNs. It consists in selecting as few active sensors as possible from all deployed nodes while ensuring sufficient sensing coverage of the monitored region. Several coverage configuration protocols have been developed; most of them presume the availability of precise knowledge about node locations and sensing ranges. Relaxing these conservative assumptions might affect the performance of coverage configuration protocols. In this chapter, the authors examine the impact of location errors, irregular sensing ranges, and packet losses on the Coverage Configuration Protocol (CCP). The authors focus more precisely on the impact of using this protocol on a real application: precision agriculture where farmers need to cover the entire terrain with sensors in order to rapidly detect and localize spots requiring chemical treatment.

A New Sensing Direction Rotation Approach to Area Coverage Optimization in Directional Sensor Network

2020 ◽  
Vol 24 (2) ◽  
pp. 206-213 ◽  
Author(s):  
Song Peng ◽  
◽  
Yonghua Xiong
Keyword(s):  
Area Coverage ◽  
Sensor Nodes ◽  
Target Area ◽  
Coverage Problem ◽  
Directional Sensor Networks ◽  
High Coverage ◽  
Coverage Ratio ◽  
Verification Algorithm ◽  
Grid Points ◽  
Directional Sensor

Coverage is a crucial issue in directional sensor networks (DSNs), and a high coverage ratio ensures a good quality of service (QoS). However, a DSN encounters various problems because they use directional sensor nodes, which are characterized by directionality and a definite sensing angle. To address the area coverage problem of DSNs, this paper proposes a new sensing direction rotation approach to optimize coverage. First, we conduct grid partitioning in the target area and propose a coverage verification algorithm to justify the coverage situation of the grid points. Then, we utilize particle swarm optimization (PSO) to find an optimal sensing direction group of the directional sensor nodes to maximize the coverage ratio. Extensive simulation experiments were conducted to prove the effectiveness and reliability of our proposed approach. The results show that the approach improves the area coverage ratio of DSNs in various scenarios.

scholarly journals A next step in disruption management: combining operations research and complexity science

2021 ◽  
Author(s):  
Mark M. Dekker ◽  
Rolf N. van Lieshout ◽  
Robin C. Ball ◽  
Paul C. Bouman ◽  
Stefan C. Dekker ◽  
...  
Keyword(s):  
Operations Research ◽  
Complexity Science ◽  
Rolling Stock ◽  
Accurate Information ◽  
Disruption Management ◽  
Railway Systems ◽  
Decentralized Decision Making ◽  
Control Situations ◽  
Management Techniques ◽  
The Impact

AbstractRailway systems occasionally get into a state of being out-of-control, meaning that barely any train is running, even though the required resources (infrastructure, rolling stock and crew) are available. Because of the large number of affected resources and the absence of detailed, timely and accurate information, currently existing disruption management techniques cannot be applied in out-of-control situations. Most of the contemporary approaches assume that there is only one single disruption with a known duration, that all information about the resources is available, and that all stakeholders in the operations act as expected. Another limitation is the lack of knowledge about why and how disruptions accumulate and whether this process can be predicted. To tackle these problems, we develop a multidisciplinary framework combining techniques from complexity science and operations research, aiming at reducing the impact of these situations and—if possible—avoiding them. The key elements of this framework are (i) the generation of early warning signals for out-of-control situations, (ii) isolating a specific region such that delay stops propagating, and (iii) the application of decentralized decision making, more suited for information-sparse out-of-control situations.

scholarly journals Integrated, Speckle-Based Displacement Measurement for Lateral Scanning White Light Interferometry

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2486
Author(s):  
Gert Behrends ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
White Light ◽  
Lateral Displacement ◽  
Displacement Measurement ◽  
Accurate Information ◽  
White Light Interferometry ◽  
Fully Integrated ◽  
Speckle Correlation ◽  
Dsc Measurements ◽  
Scanning White Light Interferometry ◽  
The Impact

Lateral scanning white light interferometry (LSWLI) is a promising technique for high-resolution topography measurements on moving surfaces. To achieve resolutions typically associated with white light interferometry, accurate information on the lateral displacement of the measured surface is essential. Since the uncertainty requirement for a respective displacement measurement is currently not known, Monte Carlo simulations of LSWLI measurements are carried out at first to assess the impact of the displacement uncertainty on the topography measurement. The simulation shows that the uncertainty of the displacement measurement has a larger influence on the total height uncertainty than the uncertainty of the displacing motion itself. Secondly, a sufficiently precise displacement measurement by means of digital speckle correlation (DSC) is proposed that is fully integrated into the field of view of the interferometer. In contrast to externally applied displacement measurement systems, the integrated combination of DSC with LSWLI needs no synchronization and calibration, and it is applicable for translatory as well as rotatory scans. To demonstrate the findings, an LSWLI setup with integrated DSC measurements is realized and tested on a rotating cylindrical object with a surface made of a linear encoder strip.

scholarly journals Laboratory test and numerical simulation of composite geomembrane leakage in plain reservoir

2021 ◽  
Vol 13 (1) ◽  
pp. 651-662
Author(s):  
Jinping Luo ◽  
Guoxiang Huang ◽  
Yanni Shao ◽  
Jian Liu ◽  
Quanyi Xie
Keyword(s):  
Laboratory Test ◽  
Water Shortage ◽  
Seepage Discharge ◽  
Threshold Distance ◽  
Water Head ◽  
Large Populations ◽  
Key Issues ◽  
Single Factor Analysis ◽  
The Impact ◽  
Leakage Location

Abstract Plain reservoir plays an important role in alleviating water shortage in plain areas which are generally crowded with large populations. As an effective and cheap anti-seepage measure, geomembrane is widely applied in plain reservoirs. Therefore, it is necessary to investigate the seepage discharge caused by composite geomembrane leakage. The laboratory test and numerical calculation are carried out in this paper to analyze the influence of three factors (i.e., water head, leakage size, and leakage location) on seepage discharge. It is found from the results of the orthogonal and single-factor analysis that the impact order of the three factors on the seepage discharge of plain reservoir is: distance from dam toe > water head > leakage size. Moreover, the seepage discharge increases as the water head, leakage size, and leakage quantity increase, in a linear relation. The opposite trend can be sawed in the seepage discharge when the distance from dam toe rises. Furthermore, a threshold distance is innovatively presented based on the results of numerical analysis. The ranking of three factors has enlightening significance for future scholars to track and study key issues of the leakage of composite geomembrane. The threshold distance presented in this paper is beneficial for engineers to manage and maintain the reservoir. Generally, the findings of this study can be beneficial to deepen the understanding of the influence of composite geomembrane leakage on the plain reservoirs.

Practitioner Review: Continuity and Change: The Fair Work Act in Aviation

2011 ◽  
Vol 53 (3) ◽  
pp. 392-401 ◽  
Author(s):  
Sue Bussell ◽  
John Farrow
Keyword(s):  
Industrial Relations ◽  
Safety Net ◽  
Aviation Industry ◽  
Continuity And Change ◽  
National Debate ◽  
New Development ◽  
Key Issues ◽  
The Individual ◽  
The Impact

This article begins by discussing the specific industrial relations challenges of the highly competitive aviation industry. It then reflects on the outcome of the recent intense national debate over industrial relations, exploring the consequences of that debate for practice and policy, and discusses some key issues that remain in play. Although the Fair Work Act 2009 may have come about as a reaction to what many perceive as the ‘excesses’ of Work Choices, the new Act does not so much ‘wind back the clock’ as represent a significant new development in Australia’s long and unique industrial relations history. This article will discuss the impact of the changes, to date, made by the Fair Work Act on one organization, including the expansion of the ‘safety net’, and how the new compromise between the role of the ‘collective’ and the role of the ‘individual’ struck by the Act has the potential to fundamentally change the nature and structure of bargaining. We offer these comments as practitioners who have worked under successive industrial relations regimes since the early 1980s.

scholarly journals Mobility-Assisted on-Demand Routing Algorithm for MANETs in the Presence of Location Errors

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Trung Kien Vu ◽  
Sungoh Kwon
Keyword(s):  
Ad Hoc ◽  
Routing Algorithm ◽  
Mobility Prediction ◽  
Location Awareness ◽  
Mobile Nodes ◽  
Location Errors ◽  
On Demand ◽  
Demand Routing ◽  
Hoc Networks ◽  
The Impact

We propose a mobility-assisted on-demand routing algorithm for mobile ad hoc networks in the presence of location errors. Location awareness enables mobile nodes to predict their mobility and enhances routing performance by estimating link duration and selecting reliable routes. However, measured locations intrinsically include errors in measurement. Such errors degrade mobility prediction and have been ignored in previous work. To mitigate the impact of location errors on routing, we propose an on-demand routing algorithm taking into account location errors. To that end, we adopt the Kalman filter to estimate accurate locations and consider route confidence in discovering routes. Via simulations, we compare our algorithm and previous algorithms in various environments. Our proposed mobility prediction is robust to the location errors.

scholarly journals Portrait of the ‘Absent’ Father: The Impact of Non-Residency on Developing and Maintaining a Fathering Role

2005 ◽  
Vol 14 (2) ◽  
pp. 134-154 ◽  
Author(s):  
Mary P. Corcoran
Keyword(s):  
Exploratory Study ◽  
Active Role ◽  
Absent Father ◽  
Key Factors ◽  
Social Barriers ◽  
Institutional Economic ◽  
Key Issues ◽  
The Impact

This paper reports on an exploratory study conducted with non-resident fathers, to elucidate the key issues affecting the development and maintenance of a fathering role after a relationship has ended. In particular, the paper focuses on the contingent nature of fatherhood for young marginalised men in Dublin. The extent to which fathers identify with a fathering role is explored and comparisons are drawn between the experiences of estranged, committed and activist fathers. Key factors that militate against fathers maintaining an active role in their children's lives are identified. The paper concludes that while the experiences of fatherhood vary across different categories of fathers, the majority of them aspire toward and value their fathering role. However, their capacity to adopt a positive fathering role is affected by a range of institutional, economic and social barriers.

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