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The expected lifetime of any wireless sensor network is a critical issue as sensor nodes are powered by small batteries. One effective approach for energy conservation, especially in high density networks, consists on switching alternatively nodes in sleep/active modes, while ensuring at the same time continuous monitoring (i.e., coverage and connectivity). In this paper we propose a novel approach...
Wireless sensor nodes can organize themselves after deployment in a large scale ad hoc network topology. Some traditional Ad hoc routing protocols do not take into account that a sensor node has limited capacities, e.g. energy. Therefore, they try to perform the sensing task regardless of the maximum hops and duration it takes. In wireless sensor networks (WSNs), this routing solution is unrealistic;...
A mobile ad hoc network is (MANET) is a network consisting of a group of wireless mobile nodes that communicate with each others without centralized control or established infrastructure. In recent years, a lot of new routing protocols have been developed in order to increase the performance of ad hoc networks. Like all wireless based system, MANET suffers for the performance limitations of a wireless...
In recent years the research of opportunistic protocols for wireless mesh networks gained lots of attention. A great number of protocols like extreme opportunistic routing (ExOR) and multiuser diversity forwarding (MDF) was proposed. Most of the performance evaluations were conducted in a constant bit-rate environment. This paper presents simulation results of the performance of existing opportunistic...
Internet connected wireless multi-hop networks are an interesting alternative for providing broadband wireless access. In order for the network to be transparent, the same services need to be available as in standard infrastructure wireless deployments. However, there is a significant challenge in providing services such as authentication, name resolution, VoIP over multi-hop mesh networks as dedicated...
Abundant hidden node collisions and correlated channel access due to multi-hop flows degrade QoS in wireless mesh networks. QoS in nearby WLANs operating on a single channel is also affected. We propose using wider contention windows for backoff to lower the risk of repeated hidden-node collisions, a spatial extension of the TXOP concept called 'express forwarding' to clear multi-hop flows sooner,...
A fundamental ambition of grid and distributed systems is to be capable of sustaining evolution and allowing for adaptability ((F. Losavio et al., 2002), (S. Radhakrishnan, 2005)). Furthermore, as the complexity and sophistication of theses structures increases, so does the need for adaptability of each component. One of the primary benefits of service oriented architecture (SOA) is the ability to...
Energy minimization is a central issue for wireless sensor networks (WSNs). We propose an energy minimization model and suggest a solution algorithm for multi-hop flat routing for WSN. This model is based on some directed minimum spanning trees and the related tree packing problem. We compare this model and some known optimization model and algorithms for two-hop hierarchical routings. In our computational...
The coordination of a team made by a set of mobile robots involves several challenges since, given a task to be accomplished by the team, the mobility of each robotic unit is often constrained by several factors. Connectivity is one of the most important factors. Cooperating robots must keep connected for many reasons: to plan a working strategy, to coordinate movements and actions, to re-configure...
In the context of distributed fusion systems, the communication between intelligent instruments, i.e. intelligent sensors and actuators, is the most important issue to deal with. The producer-consumer pattern is commonly used to facilitate the design of such systems. Then constraints based methods are commonly used to plan the data flow between instruments. The time consumption and the complexity...
For wireless sensor networks (WSNs), it is a challenging task how to schedule the energy resource to extend the network lifetime due to the fact that WSNs are usually powered by limited and non-rechargeable battery. A clustering scheme is helpful in reducing the energy consumption by aggregating data at intermediate sensor nodes. In this paper, we propose a balanced parallel k-means based clustering...
With growth demands to untethered embedded systems, e.g. sensor nodes, in the flexibility, performance, product longevity, areas, and decreasing time-to-market (TTM), programmable logic devices may allow covering lack of suitable processing units. Decrease in the feature transistor sizes allows producing smaller programmable devices and providing more computational power. However, such shrinking of...
This paper describes a goal-directed, policy-based approach to managing sensor networks in the context of a wind farm. It describes the use of policies to enable end-users to detect and handle events, and discusses how high-level goals can be used to configure both the sensor network and the monitored system. Such use of goals and policies for sensor network management is a new area of research. While...
Wireless sensor networks (WSN) are practical implementations of distributed computing ad-hoc wireless networks. Typically empowered with scarce energy resources and limited computing power, they are mainly used for in situ data acquisition and monitoring of the deployment area. As such, they are susceptible to various forms of jamming, at the physical and data link layer. Of special interest are the...
Physical clustering in wireless sensor networks results in the nomination of 'cluster heads'. The cluster head acts as a hub for the cluster. It is a specific node which has superior energy capabilities when compared with the other members of the same cluster. The nomination of cluster head is performed periodically or iteratively. This process is termed as re-clustering. Reclustering is energy-consuming...
This paper introduces an intelligent sink mechanism based on the observation and analysis of non-uniform energy consumption problem in sensor network, in which more energy consumed at nodes near the sink than at nodes far away. The proposed intelligent sink utilizes dynamic sink proxies for localized data query and collection, so as to achieve highly distributed and low energy consumption among sensor...
In this paper, we present a decentralized algorithm for node selection in unattended ground sensor networks when the goal is to minimize the localization error. The motivation behind this approach is that the sensing nodes can be better judges for the quality of their measurements than the central query node. The sensing nodes transmit their measurements to the query node when the information gain...
We present a localized algorithm (LTCA) for topology control in wireless sensor networks which has certain desirable properties. First, the algorithm is very simple, strictly local (requires 1-hop information of neighbors) and fast, requiring each node to communicate with its neighbors exactly twice. Second, LTCA does not assume the underlying graph to be a unit disk graph, and in fact works on general...
The RFID technology is one of the most quickly developing technologies of the present time. There are various applications of wireless identifiers and they are used in many fields of security as well as industrial applications. One of the limiting criteria is the price of the final transponder (tag) which includes the price of the chip and the antenna. If we implement the antenna directly on the chip...
Sensor networks have limited resources and often support large-scale applications that need scalable propagation of sensor data to users. We propose a white-board style of communication in sensor networks using a distributed real-time database supporting Virtual Full Replication with Adaptive Segmentation. This allows mobile client nodes to access, transparently and efficiently, any sensor data at...
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