Spatio-temporal event detection using probabilistic graphical models (PGMs)

The Multi-Wireless-Agent-Communication (MWAC) model uses a multiagent self-organization process through to manage communications in wireless sensor networks. This paper presents a first improvement of the MWAC model using an ant colony optimization. We introduce the use of ant colony optimization in the context of multiagent systems and wireless sensor networks. Ants are not simply deployed on the multiagent society. Each ant interacts with agents to obtain the best compromise on the routes choice to enable a reliable communication.

In this paper, we examine some of the challenges concerning error correction and multi-hop communication in wireless sensor networks (WSNs). We consider Bose, Chaudhuri and Hoquenghem (BCH) codes with different codeword lengths and error correction capabilities. In contrast with previous works, that implement coding algorithm in hardware and consequently used hardware energy profiling, in this work we consider a more realistic assumption that the node's /spl mu/-processor performs coding and energy consumption of decoding is measured using JouleTrack. Energy efficiency is used as the performance metric for communication and the interaction of multi-hop communication and coding is investigated. Simulation results show that communicating long packets is more energy efficient. If communication is multi-hop with sufficient number of hops, then, the uncoded system is beneficial. However, coding is inevitable in the case where intermediate nodes, when needed, are not available.

The quality of wireless communication makes a great impact on the performance of wireless sensor networks, but wireless communication has the notorious reputation of being unpredictable. The paper discusses reliable communication in wireless sensor networks at the data link layer. We provide reliable many-to-one and point-to-point communication ability by dynamically adjusting the power settings of the radio transceivers. Our results might be helpful for those who are puzzled by the packet loss problem in wireless sensor networks.

There is a plethora of recent research on high performance wireless communications using a cross‐layer approach in that adaptive modulation and coding (AMC) schemes at wireless physical layer are used for combating time varying channel fading and enhance link throughput. However, in a wireless sensor network, transmitting packets over deep fading channel can incur excessive energy consumption due to the usage of stronger forwarding error code (FEC) or more robust modulation mode. To avoid such energy inefficient transmission, a straightforward approach is to temporarily buffer packets when the channel is in deep fading, until the channel quality recovers. Unfortunately, packet buffering may lead to communication latency and buffer overflow, which, in turn, can result in severe degradation in communication performance. Specifically, to improve the buffering approach, we need to address two challenging issues: (1) how long should we buffer the packets? and (2) how to choose the optimum channel transmission threshold above which to transmit the buffered packets? In this paper, by using discrete‐time queuing model, we analyze the effects of Rayleigh fading over AMC‐based communications in a wireless sensor network. We then analytically derive the packet delivery rate and average delay. Guided by these numerical results, we can determine the most energy‐efficient operation modes under different transmission environments. Extensive simulation results have validated the analytical results, and indicates that under these modes, we can achieve as much as 40% reduction in energy dissipation. Copyright © 2008 John Wiley & Sons, Ltd.

Wireless industrial sensor networks are wireless sensor networks which have been adapted to industrial applications. Most techniques for wireless sensor networks can be applied to wireless industrial sensor networks. However, for industrial applications of wireless industrial sensor networks, new requirements such as real-time, reliable delivery need to be considered. In this paper, we propose EARQ, which is a novel routing protocol for wireless industrial sensor networks. It provides real-time, reliable delivery of a packet, while considering energy awareness. In EARQ, a node estimates the energy cost, delay and reliability of a path to the sink node, based only on information from neighboring nodes. Then, it calculates the probability of selecting a path, using the estimates. When packet forwarding is required, it randomly selects the next node. A path with lower energy cost is likely to be selected, because the probability is inversely proportional to the energy cost to the sink node. To achieve real-time delivery, only paths that may deliver a packet in time are selected. To achieve reliability, it may send a redundant packet via an alternate path, but only if it is a source of a packet. Experimental results show that EARQ is suitable for industrial applications, due to its capability for energy efficient, real-time, reliable communications.

Wireless sensor networks area collection of a large number of unattended sensor nodes. The sensor nodes are dynamically deployed in the region. In wireless sensor networks, the unlicensed sensor nodes use their temporarily available vacant licensed channels or spectrum band in a telecommunication network. The many open challenges with issues such as adaptive in self-organisation, fault-tolerance and network scalability with cooperative spectrum sensing and sharing are identifying new challenges in wireless sensor networks. In this paper, we proposed the bio-inspired adaptive routing algorithm for cognitive radio wireless sensor networks. The utilisation of the foraging approach of ANTs and BEEs for making the decision of using the available spectrum sensing and sharing of channels over multi-hops communication, provides the method to utilise idle channel and decrease the delay for communication in wireless sensor network. In this paper, we design the algorithm to solve the issue of wireless sensor network and performance of classical routing protocol LEACH and cognitive radio sensor networks (CRSN) evaluates the parameters which proof the self-organisation routing algorithm.

Understanding Packet Delivery Performance In Dense Wireless Sensor Networks ∗ Computer Science Department University of Southern California Los Angeles, CA 90089-0781 Jerry Zhao Computer Science Department University of Southern California Los Angeles, CA 90089-0781 Ramesh Govindan zhaoy@usc.edu ABSTRACT Wireless sensor networks promise fine-grain monitoring in a wide variety of environments. Many of these environ- ments (e.g., indoor environments or habitats) can be harsh for wireless communication. From a networking perspec- tive, the most basic aspect of wireless communication is the packet delivery performance: the spatio-temporal charac- teristics of packet loss, and its environmental dependence. These factors will deeply impact the performance of data acquisition from these networks. In this paper, we report on a systematic medium-scale (up to sixty nodes) measurement of packet delivery in three different environments: an indoor office building, a habitat with moderate foliage, and an open parking lot. Our findings have interesting implications for the design and evaluation of routing and medium-access protocols for sensor networks. ramesh@usc.edu spectrum under use, the particular modulation schemes un- der use, and possibly on the communicating devices them- selves. Communication quality can vary dramatically over time, and has been reputed to change with slight spatial displacements. All of these are true to a greater degree for ad-hoc (or infrastructure-less) communication than for wire- less communication to a base station. Given this, and the paucity of large-scale deployments, it is perhaps not surpris- ing that there have been no medium to large-scale measure- ments of ad-hoc wireless systems; one expects measurement studies to reveal high variability in performance, and one suspects that such studies will be non-representative. Wireless sensor networks [5, 7] are predicted on ad-hoc wireless communications. Perhaps more than other ad-hoc wireless systems, these networks can expect highly variable wireless communication. They will be deployed in harsh, inaccessible, environments which, almost by definition will exhibit significant multi-path communication. Many of the current sensor platforms use low-power radios which do not have enough frequency diversity to reject multi-path prop- agation. Finally, these networks will be fairly densely de- ployed (on the order of tens of nodes within communica- tion range). Given the potential impact of these networks, and despite the anecdotal evidence of variability in wireless communication, we argue that it is imperative that we get a quantitative understanding of wireless communication in sensor networks, however imperfect. Our paper is a first attempt at this. Using up to 60 Mica motes, we systematically evaluate the most basic aspect of wireless communication in a sensor network: packet delivery. Particularly for energy-constrained networks, packet de- livery performance is important, since that translates to net- work lifetime. Sensor networks are predicated using low- power RF transceivers in a multi-hop fashion. Multiple short hops can be more energy-efficient than one single hop over a long range link. Poor cumulative packet delivery per- formance across multiple hops may degrade performance of data transport and expend significant energy. Depending on the kind of application, it might significantly undermine application-level performance. Finally, understanding the dynamic range of packet delivery performance (and the ex- tent, and time-varying nature of this performance) is impor- tant for evaluating almost all sensor network communication protocols. We study packet delivery performance at two layers of the communication stack (Section 3). At the physical-layer and in the absence of interfering transmissions, packet de- Categories and Subject Descriptors C.2.1 [Network Architecture and Design]: Wireless communication; C.4 [Performance of Systems]: Perfor- mance attributes, Measurement techniques General Terms Measurement, Experimentation Keywords Low power radio, Packet loss, Performance measurement 1. INTRODUCTION Wireless communication has the reputation of being no- toriously unpredictable. The quality of wireless communica- tion depends on the environment, the part of the frequency ∗ This work is supported in part by NSF grant CCR-0121778 for the Center for Embedded Systems. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. SenSys’03, November 5–7, 2003, Los Angeles, California, USA. Copyright 2003 ACM 1-58113-707-9/03/0011 ... $ 5.00.

Communication in wireless sensor networks uses the majority of a sensor's limited energy. Using aggregation in wireless sensor network reduces the overall communication cost. Security in wireless sensor networks entails many different challenges. Traditional end-to-end security is not suitable for use with in-network aggregation. A corrupted sensor has access to the data and can falsify results. Additively homomorphic encryption allows for aggregation of encrypted values, with the result being the same as the result when unencrypted data was aggregated. Using public key cryptography, digital signatures can be used to achieve integrity. We propose a new algorithm using homomorphic encryption and additive digital signatures to achieve confidentiality, integrity and availability for in-network aggregation in wireless sensor networks. We prove that our digital signature algorithm which is based on the elliptic curve digital signature algorithm (ECDSA) is as secure as ECDSA.

Recent advancement in ubiquitous healthcare evolves to new challenges in ubiquitous communications. Secure communication in wireless sensor networks (WSNs) is one of the important issues, especially, when WSN comes to ubiquitous healthcare, where security is main requirement in sensor devices, communication and continuous real-time monitoring of patient in hospital or home network. WSN requires efficient and automated secure communication between distributed applications running upon them. Existing middleware approaches to secure communication cannot satisfy the advanced requirement in wireless sensor network. In this paper we proposed a secure progressive middleware which certainly enhance the quality of data transfer, provides secure communication and also improve the quality of service with several modules. This middleware composed on different medical sensors (tri-axial accelerometer, ECG and temperature) and healthcare application module In addition, to protect critical sensor data from unauthorized access has been considered one of the basic goal of this middleware which is achieved by implementing a PingPong-128 stream cipher algorithm in data communication from sensor devices to application modules. With this prototype a secure middleware is presented and implemented in this paper with several other measurements such as performance, portability, scalability and security.

The goal of a wireless sensor network (WSN) is to connect numerous nodes via a multi-hop self-organizing network. A variety of sensor nodes are arranged and positioned in relation to other nodes to provide safe data exchange. Sensor nodes watch as a sink node processes the data. The network includes a variety of assaults, including floods, wormhole, black hole, sinkhole, and so on. One of the most challenging tasks in WSN is secure routing because of the existence of attacks. The technology of attack detection is employed to identify attacks and enhances the security of data transmission. It provides a way to ignore network threats, enabling secure communication. Most recent efforts have been focused on implementing secure data communication in wireless sensor networks. However, the more accurate detection attack was not achieved. Numerous intrusion attackers are available to compromise network data packet communication. To provide better data distribution amongst soldiers in a combat environment, this wireless network invader node needs to be identified. Hence, in a WSN context, data transmission with a military scenario entails armed men engaged in combat, such as fighter aircraft, tankers, and shot ships. Finding intrusion attackers is a difficult task, especially in the highly dynamic military wireless sensor network. Therefore, different techniques are developed in WSN for achieving attack detection accuracy with minimal delay and maximum data delivery rate.

One of the remarkable issues that face wireless sensor networks (WSNs) nowadays is security. WSNs should provide a way to transfer data securely particularly when employed for mission-critical purposes. In this paper, we propose an enhanced architecture and implementation for 128-bit Schmidt-Samoa cryptosystem (SSC) to secure the data communication for wireless sensor networks (WSN) against external attacks. The proposed SSC cryptosystem has been efficiently implemented and verified using FPGA modules by exploiting the maximum allowable parallelism of the SSC internal operations. To verify the proposed SSC implementation, we have synthesized our VHDL coding using Quartus II CAD tool targeting the Altera Cyclone IV FPGA EP4CGX22CF19C7 device. Hence, the synthesizer results reveal that the proposed cryptographic FPGA processor recorded an attractive result in terms of critical path delay, hardware utilization, maximum operational frequency FPGA thermal power dissipation for low-power applications such as the wireless sensor networks.

Application communication in wireless sensor networks (WSN) depends on two important factors: acquisition of sensed data from a specific area, and network connectivity that concerns the reliable delivery of the observed data from sensor nodes to the sink node. In this paper, we consider the application communication reliability (ACR) of WSN supporting K-coverage in the presence of shadowing for a specific monitored area. The analytical evaluation of ACR involves two steps. We first identify all the K-coverage sets. Then, we evaluate the communication reliability of delivering the observed data from sensor nodes within the identified K-coverage sets to the sink node. Two single-path routing algorithms, shortest-path distance algorithm and shortest-path hop algorithm, are considered for evaluating the communication reliability during the second step; their performances in terms of ACR and energy consumptions are compared through an empirical analysis of several examples. Different scenarios are considered to evaluate the impact of node density, channel condition and different monitored areas on ACR. Simulation and analytical results show that WSN using the shortest-path distance algorithm is more reliable than that using the shortest-path hop algorithm in most cases, but WSN using the shortest-path hop algorithm consumes less energy for delivering the sensed data to the sink node.

The growing needs to support efficient data communications in wireless sensor networks (WSN) cannot be ignored. The resource constrained nature of WSN requires it to efficiently transmit the data with little consumption of network resources. We present a gossip based K - BackTrack (KBT) reliable data dissemination protocol for unstructured ad-hoc WSNs1. The goal of our proposed protocol is to ensure reliable data delivery and, at the same time, keeping the overhead associated with reliability low. The basic idea we employ is that each node to delay the acknowledgement message until it reaches Kth hop in the WSN. Then the Kth node then acknowledge the receipt of the message to the source directly. By increasing the value of K, we can minimize the network traffic. Moreover, the data dissemination in our proposed protocol exhibits low bandwidth cost (by minimizing the acknowledgement) and increases network lifetime (since critical sensors, ie. close to the control center are not overused). Through extensive experimental evaluation and comparison, our findings demonstrate that our protocol achieves significant improvements in energy efficiency and network lifetime.

The energy efficient Data Timed Sending (DTS) protocol enables information transfer from sensor nodes to sink host by choosing the appropriate transmission time of a short packet without data payload. Wake-up Radio (WuR) devices allow asynchronous communication of Wireless Sensor Networks (WSNs) putting the sensor nodes’ main radio modules in continuous sleep state thus increasing energy efficiency. A common characteristic for the DTS protocol and WuR is that they are designed for applications where sensors take sparse measurements, typically one measurement every few minutes. This paper investigates the combination of the DTS protocol with WuR into a single integrated solution. The analytical analysis shows that the DTS protocol significantly reduces the energy consumption when coupled with WuR making this solution suitable for applications with battery powered WSN (e.g. body area WSN).

The wireless sensor network is an emerging technology, which is used to sense and monitor the environment. As the nodes are deployed in an open environment, the security is one of the essential factors. The cryptography techniques can ensure confidentiality, integrity and authentication. However, wireless sensor network also needs to deal with inside and outside attackers. To deal with outside attackers, attacks by compromised or malicious nodes, trust management system is suggested by many researchers in the area of wireless sensor network. Trust management system can be implemented in various applications for security management such as secure data aggregation, secure cluster head selection, trusted routing, access control, etc. Many researchers provide different kind of solutions for these secure applications based on trust management. However, to incorporate, all such applications on a single sensor node in the network, it is essential to design and develop a trust management system, which considers various aspects and applications of wireless sensor network. As a result, in this paper, we would like to propose a parameter and trust factor based secure communication framework and design a trust management system for wireless sensor networks. Our main contribution is to identify various parameters and trust factors which influences on trust in wireless sensor network and developing a framework for a trust management system based on various parameters and trust factors. The working of the proposed model is shown by simulation experiments conducted in MATLAB for the application of secure communication, data aggregation and intrusion detection in wireless sensor networks.