in the last decade, decrease of the wear rate, increase in the axel load, and the velocity of the trains have changed the main damage mechanism of railway wheels from wear to rolling contact fatigue (rcf). rcf may lead to surface and subsurface cracks. the interaction between wear and rcf, removes the surface cracks, but the subsurface crack propagate gradually, and may lead to deeper and more ...

Over the last few years a theoretical treatment for the weak decays of heavy-flavour hadrons has been developed that is genuinely based on QCD. Its methodology is described as it applies to total lifetimes, and the underlying theoretical issues are discussed. Theoretical expectations are compared with present data. One discrepancy emerges: the beauty baryon lifetime appears to be significantly ...

Improving network lifetime and reliability are the fundamental challenges in Wireless Sensor Networks (WSNs). Most of the research in this area has focused on energy-efficient solutions, but has not thoroughly analyzed the network performance, e.g. in terms of data collection rate and time. A critical aspect of applications with wireless sensor networks is network lifetime. Battery-powered sens...

-Traffic patterns in wireless sensor networks (WSNs) generally follow a many-to-one model. This paper presents how to balance power consumption and maintaining the networks lifetime for sensor network. The proposed system focus the influence of multiple mobile sink nodes on power consumption and network lifetime, and mainly focus on the selection of movable sink node number moreover the selecti...

Wireless Sensor Networks consist of inexpensive nodes that are positioned over an area to collect the useful information and send the valuable data to the base station for further processing. In wireless sensor networks, nodes have limited power and shorter lifetime. So, it is crucial to aggregate the data in Energy Efficient manner and optimize the lifetime of the network. To solve the issue, ...

In Wireless Sensor Networks (WSNs), as the network consists of low-cost sensor nodes with finite battery power, power efficient strategies must be applied for data transmission in order to prolong the lifetime of the network. It is important to minimize the total energy consumption in each round so that the network lifetime is maximized. In this study, we propose a new energy efficient protocol...

An important problem in the context of wireless sensor networks is the Maximum Network Lifetime Problem (MLP): find a collection of subset of sensors (cover) each covering the whole set of targets and assign them an activation time so that network lifetime is maximized. In this paper we consider a variant of MLP, where we allow each cover to neglect a certain fraction (1−α) of the targets. We a...

Wireless sensor networks (WSNs) suffers from the hot spot problem where the sensor nodes closest to the base station are need to relay more packet than the nodes farther away from the base station. Thus, lifetime of sensory network depends on these closest nodes. Clustering methods are used to extend the lifetime of a wireless sensor network. However, current clustering algorithms usually utili...

Improving network lifetime is a fundamental challenge of wireless sensor networks. One possible solution consists in making use of mobile sinks. Whereas theoretical analysis shows that this approach does indeed benefit network lifetime, practical routing protocols that support sink mobility are still missing. In this paper, in line with our previous efforts, we investigate the approach that mak...

Enhancement of network lifetime is a key design criterion for most of the energy constrained networks as nodes are battery operated. In multi-hop wireless network, proper utilization of battery power is very much necessary to maintain network connectivity. If the battery power of a node drains quickly then its connectivity in its neighborhood will be lost. So the study of network lifetime is ve...