Energy Efficient Sensor Scheduling with a Mobile Sink Node for the Target Tracking Application

Measurement losses adversely affect the performance of target tracking. The sensor network's life span depends on how efficiently the sensor nodes consume energy. In this paper, we focus on minimizing the total energy consumed by the sensor nodes whilst avoiding measurement losses. Since transmitting data over a long distance consumes a significant amount of energy, a mobile sink node collects the measurements and transmits them to the base station. We assume that the default transmission range of the activated sensor node is limited and it can be increased to maximum range only if the mobile sink node is out-side the default transmission range. Moreover, the active sensor node can be changed after a certain time period. The problem is to select an optimal sensor sequence which minimizes the total energy consumed by the sensor nodes. In this paper, we consider two different problems depend on the mobile sink node's path. First, we assume that the mobile sink node's position is known for the entire time horizon and use the dynamic programming technique to solve the problem. Second, the position of the sink node is varied over time according to a known Markov chain, and the problem is solved by stochastic dynamic programming. We also present sub-optimal methods to solve our problem. A numerical example is presented in order to discuss the proposed methods' performanc

Wireless Sensor Technologies and Applications

Recent years have witnessed tremendous advances in the design and applications of wirelessly networked and embedded sensors. Wireless sensor nodes are typically low-cost, low-power, small devices equipped with limited sensing, data processing and wireless communication capabilities, as well as power supplies. They leverage the concept of wireless sensor networks (WSNs), in which a large (possibly huge) number of collaborative sensor nodes could be deployed. As an outcome of the convergence of micro-electro-mechanical systems (MEMS) technology, wireless communications, and digital electronics, WSNs represent a significant improvement over traditional sensors. In fact, the rapid evolution of WSN technology has accelerated the development and deployment of various novel types of wireless sensors, e.g., multimedia sensors. Fulfilling Moore’s law, wireless sensors are becoming smaller and cheaper, and at the same time more powerful and ubiquitous. [...

Water: advanced irrigation technologies

Limited opportunities to expand the volume of global freshwaters allocated to irrigation means that advanced irrigation technologies, aiming to improve efficiency of existing systems are needed, timely, and are of paramount importance. There is little scope for greater use of allocated global freshwaters for irrigation, due to unprecedented expansion since the 1950s, plus other multiple demands on that resource to meet higher living standards: projected as +400% (manufacturing), +140% (thermal electricity generation), and +130% (domestic use) by 2050 (OECD, 2012). Providing for a further 2 billion people by 2050 will challenge our ability to manage and restore natural assets, including freshwaters, on which life depends (OECD, 2012). Irrigation will need to support a projected 50% increase in global food supply to feed the additional 2 billion people (Jury and Vaux, 2007)