Sensor networks

Geographic routing offers guaranteed packet delivery in a dense network. In this routing, packets are sent to a
node which is nearer to the destination with an extensive use of
location information. However, research studies in Mobile Adhoc
Networks (MANETs) and Wireless Sensor Networks (WSNs) have
shown that packet delivery percentage can degrade substantially
when malicious nodes are found in the network. Conventional
cryptography techniques can be adopted to deal with malicious
nodes, but they cannot mitigate outsider attacks. In recent years,
a societal pattern called trust is used as a tool to mitigate security
attacks. Numerous researchers have proposed security solutions
by adopting trust in routing algorithms. However, each solution
has its strength and weakness. In this paper, an integrated
approach by using reputation and weight based trust systems
backed by Greedy Perimeter Stateless Routing (BT-GPSR) is
presented. The proposed approach outperforms the conventional
reputation and weight based methods. The effectiveness of the
proposed BT-GPSR is validated through simulation

Conventional cryptography methods alone are not
adequate for secure routing in Wireless Sensor Networks (WSNs).
These networks are more vulnerable to security attacks due to
their diverse applications, lack of supervision and limitations
in view of resource, processing and storage. To mitigate these
problems, trust is widely used as a tool to provide better
security by aiding routing protocols. In recent years, numerous
researchers have proposed wide variety of solutions based on
trust. However, all these solutions carry their own design. In this
paper, we attempt to present steps for a systematic design of trust
management systems for WSNs. In addition, we address the techniques followed by scholars in implementing trust frameworks.
Furthermore, we provide discussion on state-of-the-art research
in designing trust systems with summary and comparisons

The advance in RF energy transfer and harvesting technique over the past decade has enabled wireless energy replenishment for electronic devices, which is deemed as a
promising alternative to address the energy bottleneck of conventional battery-powered devices. In this paper, by using a
stochastic geometry approach, we aim to analyze the performance of an RF-powered wireless sensor in a downlink simultaneous wireless information and power transfer (SWIPT) system with ambient RF transmitters. Specifically, we consider the point-to-point downlink SWIPT transmission from an access point to a wireless sensor in a network, where ambient RF transmitters are distributed as a Ginibre alpha-determinantal point process (DPP), which becomes the Poisson point process when zero. In the considered network, we focus on analyzing the performance of a sensor equipped with the power-splitting architecture. Under this architecture, we characterize the expected RF energy harvesting rate of the sensor. Moreover, we derive the upper bound of both power and transmission outage probabilities. Numerical results show that our upper bounds are accurate for different value of alpha.

The more complex processes, the higher need for process transparency through high-quality real-time data. The steadily improvement of Internet-of-Things (IoT) technologies during the last years ensures this process transparency and the IoT vision of an interconnected world of objects is about to become reality. However, although these technologies allow real-time data collection, the potential of IoT technologies is not yet fully understood by all stakeholders. Furthermore, technology novices have difficulties participating in development processes and consequently prevent case-specific and relevant services from being described. This paper describes how an IoT toolkit can be used for collaborative service development. The toolkit incorporates the possibility of configuring IoT and ‘designing own algorithms’ without coding skills. This will allow IoT novices to understand sensor and actuator networks; consequently, needed sensors can be selected and individual algorithms can be defined based on individual associations.

Mobile Wireless Sensor Networks (MWSN) are becoming
increasingly common these days and are hugely used in
different applications like remotely monitoring health of patients, wild life tracking, localization and target tracking. In all these applications, mobile sensor nodes associate and communicate with different fixed coordinators. Reliable data transmission, maintaining an acceptable level of resiliency, providing seamless handover, effective target tracking and low energy consumption are few of the key requirements of effective communication in MWSNs. Out of these, the work done in this paper focuses on target tracking and the tangible need to have a seamless as well as fast handover in MWSNs. A few studies have been conducted to evaluate the performance of the IEEE 802.15.4 Media Access Control (MAC) layer in MWSNs. Moreover, the paper proposes three different target tracking schemes as part of the handover activity of sensor nodes to demonstrate the feasibility of experiencing seamless handover procedure. The schemes are properly validated through simulation studies.

Survival and development of wildlife sustains the balance and stability of the entire ecosystem. Wildlife monitoring can provide lots of information such as wildlife species, quantity, habits, quality of life and habitat conditions, to help researchers grasp the status and dynamics of wildlife resources, and to provide basis for the effective protection, sustainable use, and scientific management of wildlife resources. Wildlife monitoring is the foundation of wildlife protection and management. Wireless Sensor Networks (WSN) technology has become the most popular technology in the field of information. With advance of the CMOS image sensor technology, wireless sensor networks combined with image sensors, namely Wireless Image Sensor Networks (WISN) technology, has emerged as an alternative in monitoring applications. Monitoring wildlife is one of its most promising applications. In this paper, system architecture of the wildlife monitoring system based on the wireless image sensor networks was presented to overcome the shortcomings of the traditional monitoring methods. Specifically, some key issues including design of wireless image sensor nodes and software process design have been studied and presented. A self-powered rotatable wireless infrared image sensor node based on ARM and an aggregation node designed for large amounts of data were developed. In addition, their corresponding software was designed. The proposed system is able to monitor wildlife accurately, automatically, and remotely in all-weather condition, which lays foundations for applications of wireless image sensor networks in wildlife monitoring.

Wireless Sensor Networks have been changing and enhancing the way people perceive environment and technology. Sensors are influencing many aspects of our lives, right from cell phones to state-of-the art defence systems. In order to give fast and on-time response for different applications, it is essential that wireless sensor nodes must work in cooperation with each other. The most important requirement to maintain the coordination among different nodes is time synchronization. This paper describes a virtual time based approach for synchronizing time in sensor network among spatially close nodes. We propose the Virtual Clock Rate Algorithm for synchronizing two (or more) electronic devices employing a quartz based clock. We apply our algorithm for synchronizing single-hop sensor network. The proposed approach exploits the broadcast nature of the wireless medium and MAC layer timestamping to reduce the critical path and improve accuracy. Our approach requires two broadcasts and n transmissions for synchronizing n nodes. The key idea is to leave the system clock of the nodes untethered and use a virtual clock at each node with an exact skew rate to keep a common notion of time thus removing drift. We evaluate the performance and energy efficiency of our approach through simulation. Our approach is computationally light, energy efficient, robust to node failures and achieve long lasting synchronization.