A mobile assisted coverage hole patching scheme based on particle swarm optimization for WSNs

Wireless sensor networks (WSNs) have drawn much research attention in recent years due to the superior performance in multiple applications, such as military and industrial monitoring, smart home, disaster restoration etc. In such applications, massive sensor nodes are randomly deployed and they remain static after the deployment, to fully cover the target sensing area. This will usually cause coverage redundancy or coverage hole problem. In order to effectively deploy sensors to cover whole area, we present a novel node deployment algorithm based on mobile sensors. First, sensor nodes are randomly deployed in target area, and they remain static or switch to the sleep mode after deployment. Second, we partition the network into grids and calculate the coverage rate of each grid. We select grids with lower coverage rate as candidate grids. Finally, we awake mobile sensors from sleep mode to fix coverage hole, particle swarm optimization (PSO) algorithm is used to calculate moving position of mobile sensors. Simulation results show that our algorithm can effectively improve the coverage rate of WSNs

Adoption of new health products in low and middle income settings: how product development partnerships can support country decision making

When a new health product becomes available, countries have a choice to adopt the product into their national health systems or to pursue an alternate strategy to address the public health problem. Here, we describe the role for product development partnerships (PDPs) in supporting this decision-making process. PDPs are focused on developing new products to respond to health problems prevalent in low and middle income settings. The impact of these products within public sector health systems can only be realized after a country policy process. PDPs may be the organizations most familiar with the evidence which assists decision making, and this generally translates into involvement in international policy development, but PDPs have limited reach into endemic countries. In a few individual countries, there may be more extensive involvement in tracking adoption activities and generating local evidence. This local PDP involvement begins with geographical prioritization based on disease burden, relationships established during clinical trials, PDP in-country resources, and other factors. Strategies adopted by PDPs to establish a presence in endemic countries vary from the opening of country offices to engagement of part-time consultants or with long-term or ad hoc committees. Once a PDP commits to support country decision making, the approaches vary, but include country consultations, regional meetings, formation of regional, product-specific committees, support of in-country advocates, development of decision-making frameworks, provision of technical assistance to aid therapeutic or diagnostic guideline revision, and conduct of stakeholder and Phase 4 studies. To reach large numbers of countries, the formation of partnerships, particularly with WHO, are essential. At this early stage, impact data are limited. But available evidence suggests PDPs can and do play an important catalytic role in their support of country decision making in a number of target countries

A Smart Methodology for Deterministic Deployment of Wireless Sensor Networks

International audienceThis paper presents a smart methodology for deterministic deployment of wireless sensor networks. We discuss a set of factors involved in the wireless sensor network deployment problem, such as building abstract models, using simulation to rank deployment alternatives, and measuring the real performances of the network to verify that they meet the design goals. Network designers can use this methodology to determine the best network topology based on mission specific goals. The methodology can also be exploited to further analyze, compare, and validate deterministic deployment strategies. © 2014 IEEE

Belief Functions in Telecommunications and Network Technologies: An Overview

International audienceIn the last few years, evidence theory, also known as Dempster-Shafer theory or belief functions theory, have received growing attention in many fields such as artificial intelligence, computer vision, telecommunications and networks, robotics, and finance. This is due to the fact that imperfect information permeates the real-world applications, and as a result, it must be incorporated into any information system that aims to provide a complete and accurate model of the real world. Although, it is in an early stage of development relative to classical probability theory, evidence theory has proved to be particularly useful to represent and reason with imperfect information in a wide range of real-world applications. In such cases, evidence theory provides a flexible framework for handling and mining uncertainty and imprecision as well as combining evidence obtained from multiple sources and modeling the conflict between them. The purpose of this paper is threefold. First, it introduces the basics of the belief functions theory with emphasis on the transferable belief model. Second, it provides a practical case study to show how the belief functions theory was used in a real network application, thereby providing guidelines for how the evidence theory may be used in telecommunications and networks. Lastly, it surveys and discusses a number of examples of applications of the evidence theory in telecommunications and network technologies

New Trends in Sensor Coverage Modeling and Related Techniques: a Brief Synthesis

International audienceSensor coverage model is a mathematical formulation that attempts to quantify the sensors capability to sense some physical phenomena at some locations of interest. Typically, a space point is said to be covered if its coverage measure, the quantification output of such models, satisfies some predefined criteria depending on the application. Choosing a coverage model is a crucial step in a wide range of wireless sensor networks applications including sensor placement and sensor redundancy detection, among other problems. The aim of this paper is to briefly summarize sensor coverage models described in the literature and their related motivations and applications. © 2014 IEEE

Random Deployment of Wireless Sensor Networks

International audienceSensor placement is a fundamental issue in wireless sensor networks (WSNs). The sensor–positions can be predetermined to guarantee the quality of surveillance provided by the WSN. However, in remote or hostile sensor field, randomised sensor placement often becomes the only option. In this paper, we survey existing random node placement strategies. We categorise random placement strategies into simple and compound. An empirical study has been carried out yielding a detailed analysis of random deployment intrinsic properties, such as coverage, connectivity, fault–tolerance, and network lifespan.We also investigate the performance of a hybridisation of the simple diffusion model that places a large number of nodes around the sink and the constant diffusion that provides high coverage and connectivity rates. We show that such hybridisation ensures better performance. The obtained results give helpful design guidelines in using random deployment strategies

Performance Analysis of Caching and Forwarding Strategies in Content Centric Networking

International audienceContent-Centric Networking (CCN) is a promising implementation of the Information-Centric Networking architecture that was introduced to address recent needs related to the proliferation of multimedia traffic in the Internet. One of the fundamental features of CCN is in-network caching that aims to reduce delays, optimize bandwidth, and resource usage. Designing better in-network caching strategies along with optimal replacement policies is a challenging research issue in CCN. Moreover, the lack of a common comparison framework has obfuscated the real performance of these strategies when compared with each other. Based on realistic assumptions and a common environment, this paper gives a comprehensive view on performance comparison of popular caching strategies and replacement policies employed in CCN, while considering different forwarding strategies and multiple network topologies

An analysis of intrinsic properties of stochasticnode placement in sensor networks

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A Localized Movement-Assisted Sensor Deployment Algorithm for Hole Detection and Healing

International audienceOne of the fundamental services provided by a wireless sensor network (WSN) is the monitoring of a specified region of interest (RoI). Considering the fact that emergence of holes in the RoI is unavoidable due to the inner nature of WSNs, random deployment, environmental factors, and external attacks, assuring that the RoI is completely and continuously covered is very important. This paper seeks to address the problem of hole detection and healing in mobile WSNs. We discuss the main drawbacks of existing solutions and we identify four key elements that are critical for ensuring effective coverage in mobile WSNs: 1) determining the boundary of the RoI, 2) detecting coverage holes and estimating their characteristics, 3) determining the best target locations to relocate mobile nodes to repair holes, and 4) dispatching mobile nodes to the target locations while minimizing the moving and messaging cost. We propose a lightweight and comprehensive solution, called holes detection and healing (HEAL), that addresses all of the aforementioned aspects. The computation complexity of HEAL is O(v2) , where v is the average number of 1-hop neighbors. HEAL is a distributed and localized algorithm that operates in two distinct phases. The first identifies the boundary nodes and discovers holes using a lightweight localized protocol over the Gabriel graph of the network. The second treats the hole healing, with novel concept, hole healing area. We propose a distributed virtual forces-based local healing approach where only the nodes located at an appropriate distance from the hole will be involved in the healing process. Through extensive simulations we show that HEAL deals with holes of various forms and sizes, and provides a cost-effective and an accurate solution for hole detection and healing

QoS‐FS: a new forwarding strategy with QoS for routing in Named Data Networking

International audienceInformation-Centric Networking (ICN) is a novel paradigm for future Internet architectures. The aim of ICN is to accommodate content distribution within the Internet infrastructure. Named Data Networking (NDN) is one of the most popular ICN proposal. This paper presents a design of QoS-FS, a new NDN's adaptive forwarding strategy with quality of service (QoS). At each node of the network, QoS-FS monitors, in real-time, ingoing and outgoing networks' link to estimate the QoS parameters and integrate them into the different decisions taken to determine when and which interface to use to forward an Interest. Therefore, making forwarding decision adaptive to network conditions and user's preferences. We provide simulation experiments to demonstrate the efficiency of the proposed solution