Sensor Node

Abstract— With the continuous development of the wireless technology, securing wireless sensor networks became more and more a crucial but also a demanding task. In this paper we propose a combined strategy that is meant to discover malicious nodes within a wireless sensor ...

This paper proposes a compact Thévenin model for a rectenna. This model is then applied to design a high-efficiency radio frequency harvester with a maximum power point tracker (MPPT). The rectenna under study consists of an L-matching network and a half-wave rectifier. The derived model is simpler and more compact than those suggested so far in the literature and includes explicit expressions of the Thévenin voltage (Voc) and resistance and of the power efficiency related with the parameters of the rectenna. The rectenna was implemented and characterized from −30 to −10 dBm at 808 MHz. Experimental results agree with the proposed model, showing a linear current–voltage relationship as well as a maximum efficiency at Voc/2, in particular 60% at −10 dBm, which is a remarkable value. An MPPT was also used at the rectenna output in order to automatically work at the maximum efficiency point, with an overall efficiency near 50% at −10 dBm. Further tests were performed using a nearby tra...

Wireless sensor networks (WSNs) have attracted a lot of interest over the last decade in wireless and mobile computing research community.  Applications of WSNs are numerous and growing, which range from indoor deployment scenarios in the home and office to outdoor deployment in adversary’s territory in a tactical battleground. However, due to distributed nature and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their performance. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Design and implementation of secure WSNs is, therefore, a particularly challenging task. This chapter provides a comprehensive discussion on the state of the art in security technologies for WSNs. It identifies various possible attacks at different layers of the communication protocol stack in a typical WSN and presents their possible countermeasures. A brief discussion on the future direction of research in WSN security is also included.

Developing hardware, algorithms and protocols, as well as collecting data in sensor networks are all important challenges in building good systems. We describe a vertical system integration of a sensor node and a toolkit of machine learning algorithms. Based on a dataset that combines sensor data with additional introduced data we predict the number of persons in a closed space.

Wireless sensor networks (W  ) are widely used in many applications including military surveillance, habitat

monitoring, and health care.W  are usually composed of a large amount of sensor nodes with limited

resources, and are usuallydeployed in unattended environments. In such environments, the security of sensor

nodes is very important. Once a node is compromised, the adversary will disclose all the secret information

stored in that node.The adversary can then use the compromised nodes to launch false data injection attacks,i.e.

to inject bogus reports intosensor networks. Defending false data injection attacks is an important research issue

in W  , because this type of attacksnot only causes false alarms that waste real-world response efforts (e.g.

sending response teams to the event location), butalso may drain out the constrained resources of the forwarding

sensors.

To prevent such false data injection attacks several filtering method exist. We study these methods. With the rapid

development of hardware and wireless network technologies, wireless sensor networks (W  ) have been widely

applied in ubiquitous computing system. Because these W  are often unattended when deployed in security

sensitive areas such as hostile fields or homeland security operations, they are prone to capture and may have

their security compromised

There are various applications of Wireless Sensor Networks (WSNs) including industrial, environmental, military, health applications etc. Gathering information about a given condition of environment in a given zone is the main task of these networks. The sensors are being deployed manually or randomly in the area to be monitored. Sensors are very small size and having different constraints like low energy, low communication range and low storage. The deployment strategies for WSN must be able to cope with obstacles and be energy efficient in order to increase the network lifetime. The deployment process is very much important in WSNs because coverage and connectivity is totally dependent on this. Here in this paper we present a review of coverage and connectivity issues and the impact of deployment on these factors. The paper presents the analysis of deployment issues and the factors influencing the deployment of WSNs. In conclusion he paper gives current trends and open issues in this area.

— The wireless sensor network (WSN) has set of wireless intelligent sensor nodes with high speed network. Nodes are deployed randomly in a surge of unanticipated applications. The routing is one of the most important challenges in WSNs for data transmission over the sensor nodes. The paper proposes the data aware routing in WSNs, which incorporates energy efficient routing of data. The objective of the proposed work is to improve the performance of network in terms of energy consumption and throughput. The simulation results show that the proposed approach perform better in-terms of utilization of minimum energy, efficient for cluster formation, and reduce communication overhead in WSNs.

This paper presents a self organized asynchronous medium access control (MAC) protocol for wireless body area sensor (WBASN). The protocol is optimized in terms of latency and energy under variable traffic. A body sensor network (BSN) exhibits a wide range of traffic variations based on different physiological data emanating from the monitored patient. For example, electrocardiogram data rate is multiple times more in comparison with body temperature rate. In this context, we exploit the traffic characteristics being observed at each sensor node and propose a novel technique for latency-energy optimization at the MAC layer. The protocol relies on dynamic adaptation of wake-up interval based on a traffic status register bank. The proposed technique allows the wake-up interval to converge to a steady state for variable traffic rates, which results in optimized energy consumption and reduced delay during the communication. A comparison with other energy efficient protocols is presented. The results show that our protocol outperforms the other protocols in terms of energy as well as latency under the variable traffic of WBASN.

Wireless Sensor Network (WSNs) have a vast field of applications, including environment monitoring, battlefield surveillance and targeting system. As WSNs are usually deployed in remote or even hostile environments and sensor node are prone to node compromise attacks, the adoption of dynamic key management is extremely important. However, there sourceconstrained nature of sensor nodes hinders the use of dynamic key management solutions designed for wired and adhoc networks. Hence, many dynamic key management schemes have been proposed for WSNs recently. This paper investigates the special requirements of dynamic key management in sensor network environment, and introduces several basic evaluation metrics. In this work, the state of the art dynamic key management schemes are classified into different groups and summarized based on the evaluation metrics. Finally, several possible future research directions for dynamic key management are provided.

This paper proposes S-MAC, a medium-access control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use battery-operated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect sensor networks to be deployed in an ad hoc fashion, with individual nodes remaining largely inactive for long periods of time, but then becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in almost every way: energy conservation and self-configuration are primary goals, while per-node fairness and latency are less important. S-MAC uses three novel techniques to reduce energy consumption and support self-configuration. To reduce energy consumption in listening to an idle channel, nodes periodically sleep. Neighboring nodes form virtual clusters to auto-synchronize on sleep schedules. Inspired by PAMAS, S-MAC also sets the radio to sleep during transmissions of other nodes. Unlike PAMAS, it only uses in-channel signaling. Finally, S-MAC applies message passing to reduce contention latency for sensor-network applications that require store-and-forward processing as data move through the network. We evaluate our implementation of S-MAC over a sample sensor node, the Mote, developed at University of California, Berkeley. The experiment results show that, on a source node, an 802.11-like MAC consumes 2-6 times more energy than S-MAC for traffic load with messages sent every 1-10 s.

Many embedded system applications involve storing and querying large datasets. Existing research in this area has focused on adapting and applying conventional database algorithms to embedded devices. Algorithms designed for processing queries on embedded devices must be able to execute given the small amount of available memory and energy constraints. Most embedded devices use flash memory to store large amounts of data. Flash memory has unique performance characteristics that can be exploited to improve algorithm performance. In this paper, we describe the Flash MinSort external sorting algorithm that uses an index, generated at runtime, to take advantage of fast random reads in flash memory. This algorithm adapts to the amount of memory available and performs best in applications where sort keys are clustered. Experimental results show that Flash MinSort is two to ten times faster than previous approaches for small memory sizes where external merge sort is not executable.

Wireless sensor networks (WSNs) have received significant research focus due to their widespread applicability in military, health care, agriculture, environment monitoring applications. These applications require WSNs to be self-organized and mobile. Clustering techniques are particularly important in the success of WSN implementations especially when sensor nodes are moving at different speeds. Many existing clustering algorithms assume that sensor nodes move at the same speed which is not true in many practical cases. Thus, in this paper, we introduce a velocity-based clustering algorithm and implement a relay placement technique in order to maintain seamless network connectivity. Simulation results show that the packet loss rate of the proposed algorithm is much lower than the existing LEACH and HEED clustering protocols.

The performance of several existing and partly new algorithms for positioning of sensor node based on distance estimate is compared when the distance estimates are obtained from a measurement campaign. The distance estimates are based on time-of-arrival measurements done by ultrawideband devices in an indoor office environment. Two different positioning techniques are compared: statistical and geometrical. In statistical category, distributed weighted-multidimensional scaling (dwMDS), least squares, and sum ...

... and Miriam Cunningham (Eds) IIMC International Information Management Corporation, 2010 ISBN: 978-1-905824-18-2978-1-905824-1 6-8 Testing for normality of UWB-based distance measurements by the Anderson-Darling statistic Pau Closas, Javier Arribas and Carles ...