On March 4, 1999, the Wide-Field Infrared Explorer (WIRE) was launched from Vandenberg Air Force Base on a Pegasus XL launch vehicle into a 540 km orbit with a planned mission duration of four months. WIRE was designed to conduct a deep infrared, extra galactic science survey 500 times more sensitive than the Infrared Astronomy Satellite (IRAS) Faint Source Catalog. The instrument consists of a...

In the liner-ejecta experiments carried out at the Los Alamos pulsed power facility Pegasus II, a solid liner was magnetically imploded to impact on a target cylinder to produce the shockinduced ejecta. As a result of improved time resolution for the B-dot (dB/dt) probes fielded last fall, we began to notice a sharp jump in the B-dot curve occurring at a time very close to the expected liner-ta...

The WSN is composed of a collection of sensor nodes, which are small energy constrained devices. In wireless sensor networks, the energy of nodes is limited. So designing efficient routing for reducing energy consumption is the important factor. This paper mainly focused on the routing problem in Wireless Sensor Networks and proposed three routing strategies named as CCB (Cluster and Chain Base...

The efficiency of wireless sensor network largely depends on the routing protocol used. Routing is a major challenge for sensor networks as it presents a trade-off between responsiveness and efficiency. Hierarchical class of routing protocols introduces a structure on the network to achieve stability, energy efficiency and scalability. There are various protocols existing in this category. In t...

Heterogeneous wireless sensor network consists of wireless sensor nodes with different abilities, such as different computing power and different initial energy. We present in this paper a new scheme for maximizing heterogeneous WSN lifetime. The proposed scheme employs two types of sensor nodes that are named (consistent with IEEE 802.15.4 standard) Full Function Device (FFD) and Reduced Funct...

Wireless sensor network (WSN) is a new and fast advancing technology, which is opening up many opportunities in the field of remote sensing and data monitoring. In spite of the numerous applications of WSN, issues related to determining a suitable and accurate radio model that will foster energy conservation in the network limit the performance of WSN routing protocols. A number of radio models...

We propose Grid Block Energy based hierarchical Data Gathering (GBE-DG) algorithms for wireless sensor networks. We divide the whole sensor network into grid blocks of equal size. The energy level of a grid block is the sum of the energy levels of the sensor nodes located in it. The grid block that has the maximum energy level is called the leader grid block (LGB) and the sensor node that has t...

This paper proposes a new hierarchical routing algorithm for wireless sensor networks called hybrid QEA-based energy-efficient routing algorithm (HERA), which is based on LEACH and PEGASIS algorithms in the environment of wireless sensor networks. In order to reduce the data transmission distance, this algorithm uses the hybrid quantum evolutionary algorithm (HQEA) to establish the best cluster...

Wireless sensor networks have recently gained a lot of attention from the researches. Wireless sensor networks are often partitioned into clusters, each managed by a cluster head (gateway). This paper reviews medium access control (MAC), an enabling technology in wireless sensor networks. MAC protocols control how sensors access a shared radio channel to communicate with neighbors in small area...

Due to limitation of battery power, wireless sensor nodes are highly energy constrained. So, to enhance the network lifetime, the protocols which are used in wireless sensor network should be energy efficient. The LEACH and PEGASIS protocols which are elegant solutions to this problem try to minimize the overall energy dissipation by the nodes in the network. While the LEACH protocol randomizes...