Wireless sensor and actor networks (WSANs) refer to a group of sensors and actors linked by wireless medium to perform distributed sensing and acting tasks. The realization of wireless sensor and actor networks (WSANs) needs to satisfy the requirements introduced by the coexistence of sensors and actors. In WSANs, sensors gather information about the physical world, while actors take decisions and then perform appropriate actions upon the environment, which allows a user to effectively sense and act from a distance. In order to provide effective sensing and acting, coordination mechanisms are required among sensors and actors. Moreover, to perform right and timely actions, sensor data must be valid at the time of acting. This paper explores sensor-actor and actor-actor coordination and describes research challenges for coordination and communication problems.

Wireless sensor and actor networks: research challenges

Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, ‘‘ad-hoc’’ network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANETs characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future. � 2003 Elsevier B.V. All rights reserved.

/pdf/mobile-ad-hoc-networking-imperatives-and-challenges-56mord86q0.pdf

Mobile ad hoc networking: imperatives and challenges

Thank you for downloading linear and nonlinear programming. As you may know, people have search numerous times for their favorite novels like this linear and nonlinear programming, but end up in malicious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they juggled with some infectious bugs inside their desktop computer. linear and nonlinear programming is available in our book collection an online access to it is set as public so you can download it instantly. Our digital library spans in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the linear and nonlinear programming is universally compatible with any devices to read.

Linear And Nonlinear Programming

The extent to which member states transpose EU directives in a timely fashion is often argued to be strongly associated with the general effectiveness of national bureaucracies. But what kind of institutional solutions ensure better performance? This paper examines the patterns and effects of departmental oversight across 28 ministries in Estonia, Hungary, Poland and Slovenia. In mapping the strength of oversight, it relies on around 90 structured interviews regarding the rules-in-use on transposition planning, legal review and monitoring of deadlines. The analysis of the impact of departmental oversight is based on an original dataset of over 300 directives with transposition deadlines between January 2005 and December 2008.

On the european union

https://www.eecs.ucf.edu/~turgut/Research/Publications/Download/Boukerche-2011-ComputerNetworks.pdf

Survey Paper: Routing protocols in ad hoc networks: A survey

Ad hoc networking is a new paradigm of wireless communications for mobile nodes. Mobile ad hoc networks work properly only if the partecipating nodes cooperate to network protocols. Cooperative algorithms make the system vulnerable to user misbehavior as well as to malicious and selfish misbehavior. Nodes act selfishly to save battery power, by not cooperating to routing-forwarding functions. Lack of cooperation may severely degrade the performance of the ad hoc system. This paper presents a new approach to cope with cooperation misbehavior, focusing on the forwarding function. We present a general framework, based on reliability indices taking into account not only selfish/malicious misbehavior, but also situations of congestion and jammed links. We aim at avoiding unreliable routes and enforcing cooperation, thus increasing network “performability” (performance and reliability).

/pdf/towards-reliable-forwarding-for-ad-hoc-networks-51aweyecrl.pdf

Towards Reliable Forwarding for Ad Hoc Networks

MobileMAN is a project funded by the Future and Emerging Technologies arm of the IST Programme of the the European Commission. This project investigates the potentialities of the Mobile Ad hoc NETworks (MANET’s) paradigm. Specifically, the project aims at defining and developing a metropolitan area, self-organizing, and totally wireless network, called Mobile Metropolitan Ad hoc Network (MobileMAN). The main technical output of this proposal can be summarized as follow. i) Development, validation, implementation and testing of the architecture, and related protocols, for configuring and managing a MobileMAN. ii) Physical implementation of this architecture for lowers layers (i.e., wireless technologies). iii) Integration of applications on top of our self-organized network. iv) Validation of the self-organizing paradigm from the social and economic standpoint.

/pdf/mobileman-mobile-metropolitan-ad-hoc-networks-52sn1sj8zp.pdf

MobileMAN: Mobile Metropolitan Ad Hoc Networks

Recently RFID technology has made its way into end-user applications, enabling automatic item identification without requiring line of sight. In particular passive tags provide a promising, low cost and energy-efficient solution for inventory applications. However, their large-scale adoption strictly depends on the efficiency of the identification process. A major challenge is how to arbitrate channel access so that all tags are able to answer the reader inquiries and identify themselves over time. This paper stems from the observation that a variety of anti- collision protocols for RFIDs have been proposed in the literature. However, a thorough simulation comparison among them and a clear identification of the mechanisms resulting in better end- to-end performance is lacking. The objective of our work has been to fill this gap. This paper presents the results of a detailed ns2-based comparative evaluation of representatives of all the classes of anti-collision protocols so far proposed. Simulation results show that end-to-end performance of the different classes of protocols in terms of metrics such as the time needed for tags identification differ significantly over what previously found by experiments which only focused on the number of reading cycles for tag identification. Our thorough performance evaluation has highlighted that different solutions are to be used in different application scenarios and that decreasing the collisions (rather than idle times) is the way to go to further improve anti-collision protocols performance. I. INTRODUCTION A basic RFID system consists of a reader and a set of tags. The reader inquiries tags that are able to communicate on the radio channel, returning their ID. Tags are typically passive devices, which answer to reader's query by back- scattering the received signal. One of the main objectives of a RFID system is the identification of all the tags present in the area covered by the reader. The challenges related to tags identification depend on the reference scenarios, which may include one or more readers, and a variable or stationary set of tags. The coexistence of multiple readers in the same area may cause collisions among readers interfering with each other or with tags. Moreover, collisions may occur among tags simultaneously transmitting to the same reader, indepen- dently of the presence of one or more readers. Collisions are addressed by specific solutions for the multi-reader problem (through frequency allocation mechanisms) and the single- reader problem (through collision arbitration schemes). The other distinguishing factor is given by scenario variability. In case of stationary applications scenarios (i.e., consecutive readings of the same, slightly changed, set of tags), the reader

http://senseslab.di.uniroma1.it/administrator/components/com_jresearch/files/publications/PerformanceAnalysisOfAnti-collisionProtocolsForRFIDSystems.pdf

Performance Analysis of Anti-Collision Protocols for RFID Systems

The emergent commercial use of techniques for Radio Frequency-based IDentification of different items (RFID) requires the investigation and testing of collision resolution mechanisms for the efficient and correct communication between the system reader and the tags labeling the items that need to be identified. Several MAC protocols have been proposed to resolve collisions in RFID networks. A recent solution, named Tree Slotted Aloha (TSA), has been shown to outperform previous ones with respect to the time it takes for identifying all tags, and the total number of bits transmitted to complete the identification process. However, almost half of the time needed by TSA for identifying tags is spent in collisions. This depends on TSA operation and in particular on the way TSA estimates the number of colliding tags. We have observed that in the case of realistically large networks, TSA highly underestimates this number, with non-negligible impact on the protocol performance. In this paper, we propose a Dynamic Tree Slotted Aloha (Dy TSA) protocol that exploits the knowledge acquired during ongoing readings to refine the estimation of the number of colliding tags. In so doing, Dy TSA adapts the length of the following reading cycles to the actual number of tags still requiring identification. Through ns2-based simulations we show that the proposed method is effective for tag identification and results in significantly improved performance over TSA. Specifically, the length of the identification process is up to 20% lower than that of TSA. Furthermore, the amount of transmitted bits needed for identifying all tags decreases up to 30%.

http://senseslab.di.uniroma1.it/administrator/components/com_jresearch/files/publications/DynamicTagEstimationForOptimizingTreeSlottedAlohaInRFIDNetworks.pdf

Dynamic tag estimation for optimizing tree slotted aloha in RFID networks

We present a distributed, integrated medium access control, scheduling, routing and congestion/rate control protocol stack for cognitive radio ad hoc networks (CRAHNs) that dynamically exploits the available spectrum resources left unused by primary licensed users, maximizing the throughput of a set of multi-hop flows between peer nodes. Using a network utility maximization (NUM) formulation, we devise a distributed solution consisting of a set of sub-algorithms for the different layersof the protocol stack (MAC, flow scheduling and routing), which result from a natural decomposition of the problem intosub-problems. Specifically, we show that: 1) The NUM optimization problem can be solved via duality theory in a distributed way, and 2) the resulting algorithms can be regarded as the CRAHN protocols. These protocols combine back-pressure scheduling with a CSMA-based random access with exponential backoffs. Our theoretical findings are exploited to provide a practical implementation of our algorithms using a common control channel for node coordination and a wireless spectrum sensor network for spectrum sensing. We evaluate our solutions through ns-2 MIRACLE-based simulations. Our results show that the proposed protocol stack effectively enables multiple flows among cognitive radio nodes to coexist with primary communications. The CRAHN achieves high utilization of the spectrum left unused by the licensed users, while the impact on their communications is limited to an increase of their packet error rate that is below 1 percent.

http://senseslab.di.uniroma1.it/administrator/components/com_jresearch/files/publications/Throughput_optimal_Cross_layer.pdf

Gaia Maselli

Papers

Towards Reliable Forwarding for Ad Hoc Networks

MobileMAN: Mobile Metropolitan Ad Hoc Networks

Performance Analysis of Anti-Collision Protocols for RFID Systems

Dynamic tag estimation for optimizing tree slotted aloha in RFID networks

Throughput-Optimal Cross-Layer Design for Cognitive Radio Ad Hoc Networks