Robotic Wireless Sensor Networks

In this chapter, we present a literature survey of an emerging, cutting-edge, and multi-disciplinary field of research at the intersection of Robotics and Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system that aims to achieve certain sensing goals while meeting and maintaining certain communication performance requirements, through cooperative control, learning and adaptation. While both of the component areas, i.e., Robotics and WSN, are very well-known and well-explored, there exist a whole set of new opportunities and research directions at the intersection of these two fields which are relatively or even completely unexplored. One such example would be the use of a set of robotic routers to set up a temporary communication path between a sender and a receiver that uses the controlled mobility to the advantage of packet routing. We find that there exist only a limited number of articles to be directly categorized as RWSN related works whereas there exist a range of articles in the robotics and the WSN literature that are also relevant to this new field of research. To connect the dots, we first identify the core problems and research trends related to RWSN such as connectivity, localization, routing, and robust flow of information. Next, we classify the existing research on RWSN as well as the relevant state-of-the-arts from robotics and WSN community according to the problems and trends identified in the first step. Lastly, we analyze what is missing in the existing literature, and identify topics that require more research attention in the future

Location-Quality-aware Policy Optimisation for Relay Selection in Mobile Networks

Relaying can improve the coverage and performance of wireless access networks. In presence of a localisation system at the mobile nodes, the use of such location estimates for relay node selection can be advantageous as such information can be collected by access points in linear effort with respect to number of mobile nodes (while the number of links grows quadratically). However, the localisation error and the chosen update rate of location information in conjunction with the mobility model affect the performance of such location-based relay schemes; these parameters also need to be taken into account in the design of optimal policies. This paper develops a Markov model that can capture the joint impact of localisation errors and inaccuracies of location information due to forwarding delays and mobility; the Markov model is used to develop algorithms to determine optimal location-based relay policies that take the aforementioned factors into account. The model is subsequently used to analyse the impact of deployment parameter choices on the performance of location-based relaying in WLAN scenarios with free-space propagation conditions and in an measurement-based indoor office scenario.Comment: Accepted for publication in ACM/Springer Wireless Network

Multimedia delivery in the future internet

The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio and video are produced, distributed, shared, managed and consumed on-line through various networks, like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked challenges of the Networked Media in the transition to the Future of the Internet. Internet has evolved and changed the way we work and live. End users of the Internet have been confronted with a bewildering range of media, services and applications and of technological innovations concerning media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged that in a near- to mid-term future, the Internet will provide the means to share and distribute (new) multimedia content and services with superior quality and striking flexibility, in a trusted and personalized way, improving citizens’ quality of life, working conditions, edutainment and safety. In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and innovative applications “on the move”, like virtual collaboration environments, personalised services/ media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to contribute towards such a vision. Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6) and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way ahead in the area of Content Aware media delivery platforms

Unaprjeđenje cjelovitosti vojno-obrambenih komunikacijskih sustava s pomoću mrežnih pristupnih točaka s naglaskom na zemaljskim radiorelejnim vezama

Obvious changes in a very broad field of the information and communication technologies are the key driver of the accelerated development of every sphere of human activity, including private life. In the military organization, this technological progress is present through the “post 2000” concept of the networked implementation of operations, which is implemented to varying degrees in armies around the world. New confrontations on the modern front include demands for an ever-increasing volume of the electronic traffic, complexity of the systems that generate, share and consume information content, and above all, the fastest possible availability of the relevant information. The race for information superiority is accompanied, on the other hand, by an ever more destructive highly sophisticated threats, from classic degradations and physical destruction, action of the hybrid (intelligence-combat) platforms of the unmanned systems, to cyber-electromagnetic activities of an offensivedefensive nature. The new paradigms of the multi-domain warfare and expected scenarios that such forms of engagement put forward, demand from the modern military organization further normative arrangements within the functional area related to communication information systems. At the operational-strategic level, they imply the introduction of adequate organizational concepts and doctrines, while in the implementation part they require correction of the established tactics, techniques and procedures. In such an operational environment, integrative efforts within today’s militarydefence communication systems transformed into unique complete solutions have brought a special challenge. Key networking of the mission components is provided by network access points. For this reason, they are the subject of special attention of the network designers, both conceptually and in terms of implementation. The effectiveness of their functioning is also an assessment of the maturity of military thinking, inventiveness and engineering practice – which will bring along defeats or victories to any combat system in future challenges.Očigledne promjene na vrlo širokom području informacijsko-komunikacijskih tehnologija ključni su pokretač ubrzanog razvoja svake sfere ljudskog djelovanja – uključujući i privatni život. U vojnoj organizaciji ovaj tehnološki napredak prisutan je kroz tzv. post 2000 koncept umrežene provedbe operacija – koji se u različitim stupnjevima implementira u vojskama širom svijeta. Nova sučeljavanja na suvremenoj bojišnici uključuju zahtjeve za sve većim volumenom elektroničkih prometnica, usložnjavanja sustava koji generiraju, dijele i konzumiraju informacijske sadržaje te prije svega što bržu dostupnost relevantnih informacija. Utrku za informacijskom superiornošću s druge strane prate nikad destruktivnije visokosofisticirane prijetnje – od klasičnih degradacija i fizičkih uništenja, djelovanja hibridnih (obavještajno-borbenih) platformi besposadnih sustava, do kiberelektromagnetskih aktivnosti napadajno-obrambene prirode. Nove paradigme višedomenskog ratovanja i očekujući scenariji koje takvi oblici angažmana donose, od suvremene vojne organizacije traže daljnja normativna uređenja unutar funkcionalnog područja vezanog uz komunikacijsko-informacijske sustave. Ona na operativno-strategijskoj razini podrazumijevaju uvođenje adekvatnih organizacijskih koncepata i doktrina, dok u provedbenom dijelu traže korigiranje ustaljenih taktika, tehnika i procedura. U takvom operativnom okružju, poseban izazov donose integrativni napori unutar vojno-obrambenih komunikacijskih sustava današnjice, pretočeni u jedinstvena cjelovita rješenja. Ključnu umreženost misijskih sastavnica osiguravaju mrežne pristupne točke. Zbog tog su razloga predmetom od posebne pozornosti mrežnih dizajnera, i u konceptualnom i u izvedbenom smislu. Učinkovitost njihova funkcioniranja, ujedno je i ocjena zrelosti vojnog promišljanja, inventivnosti i inženjerske prakse – koja će u budućim izazovima svakom borbenom sustavu donositi poraze ili pobjede

Mathematical Models and Algorithms for Network Flow Problems Arising in Wireless Sensor Network Applications

We examine multiple variations on two classical network flow problems, the maximum flow and minimum-cost flow problems. These two problems are well-studied within the optimization community, and many models and algorithms have been presented for their solution. Due to the unique characteristics of the problems we consider, existing approaches cannot be directly applied. The problem variations we examine commonly arise in wireless sensor network (WSN) applications. A WSN consists of a set of sensors and collection sinks that gather and analyze environmental conditions. In addition to providing a taxonomy of relevant literature, we present mathematical programming models and algorithms for solving such problems. First, we consider a variation of the maximum flow problem having node-capacity restrictions. As an alternative to solving a single linear programming (LP) model, we present two alternative solution techniques. The first iteratively solves two smaller auxiliary LP models, and the second is a heuristic approach that avoids solving any LP. We also examine a variation of the maximum flow problem having semicontinuous restrictions that requires the flow, if positive, on any path to be greater than or equal to a minimum threshold. To avoid solving a mixed-integer programming (MIP) model, we present a branch-and-price algorithm that significantly improves the computational time required to solve the problem. Finally, we study two dynamic network flow problems that arise in wireless sensor networks under non-simultaneous flow assumptions. We first consider a dynamic maximum flow problem that requires an arc to transmit a minimum amount of flow each time it begins transmission. We present an MIP for solving this problem along with a heuristic algorithm for its solution. Additionally, we study a dynamic minimum-cost flow problem, in which an additional cost is incurred each time an arc begins transmission. In addition to an MIP, we present an exact algorithm that iteratively solves a relaxed version of the MIP until an optimal solution is found

Performance of information discovery and message relaying in mobile ad hoc networks

This paper presents 7DS, a novel peer-to-peer resource sharing system. 7DS is an architecture, a set of protocols and an implementation enabling the exchange of data among peers that are not necessarily connected to the Internet. Peers can be either mobile or stationary. We focus on three different facets of cooperation, namely, data sharing, message relaying and network connection sharing. 7DS enables wireless devices to discover, disseminate, relay information among each other to increase the data access. We evaluate via extensive simulations the effectiveness of our system for data dissemination and message relaying among mobile devices with a large number of user mobility scenarios. We model several general data dissemination approaches and investigate the effect of the wireless coverage range, 7DS host density, and cooperation strategy among the mobile hosts as a function of time. We also present a power conservation mechanism that is beneficial, since it increases the power savings, without degrading the data dissemination. Using theory from random walks, random environments and diffusion of controlled processes, we model one of these data dissemination schemes and show that the analysis confirms the simulation results for this scheme