We consider distributed information retrieval for sensor networks with cluster heads or mobile access points. The performance metric used in the design is energy efficiency defined as the ratio of the average number of bits reliably retrieved by the access point to the total amount of energy consumed. A distributed opportunistic transmission protocol is proposed using a combination of carrier s...

Wireless sensor networks have been developed in the way of higher speed, more stability, and more energy efficiency in recent years. Because most wireless sensors are powered by energy-constrained batteries, efficient energy consumption plays the most important role in the design of wireless sensor networks. For energy efficiency, aside from economizing the use of power in the sensor hardware, ...

Four-dimensional scanning ultrafast electron microscopy is used to investigate doping- and carrier-concentration-dependent ultrafast carrier dynamics of the in situ cleaved single-crystalline GaAs(110) substrates. We observed marked changes in the measured time-resolved secondary electrons depending on the induced alterations in the electronic structure. The enhancement of secondary electrons a...

Numerical modeling has shown that carrier cooling and carrier heating strongly influence saturation dynamics and pulse shaping in bulk semiconductor absorbers. With no electric field in the absorbing region, carrier cooling leads to strong additional fast saturation of absorption. The saturation causes a substantial decrease in the saturation energies for subpicosecond pulses in comparison with...

The past decades witnessed the application of adaptive coding and modulation (ACM) in satellite links. However, ACM technologies come at cost higher complexity when designing network's carrier plan user terminals. Accounting for those issues is even more important link uses frequencies Ka band above, where attenuation caused by tropospheric phenomena a major concern. In th...

One of the features of wireless sensor networks is that the nodes in this network have limited power sources. Therefore, assessment of energy consumption in these networks is very important. What has been common practice has been the use of traditional simulators to evaluate the energy consumption of the nodes in these networks. Simulators often have problems such as fluctuating output values i...

Due to the increasing use of wireless communications, infrastructure-less networks such as Delay Tolerant Networks (DTNs) should be highly considered. DTN is most suitable where there is an intermittent connection between communicating nodes such as wireless mobile ad hoc network nodes. In general, a message sending node in DTN copies the message and transmits it to nodes which it encounters. A...

The size of the carrier sensing range has a great impact on the network performance. Previous studies have focus on computing asymptotic optimum carrier sensing range using unrealistic interference models. In this paper, based on realistic interference model, we propose a framework to determine the optimum carrier sensing range of a network. By regarding the given network and the settings as in...

Plasmon-induced hot carrier formation is attracting an increasing research interest due to its potential for applications in photocatalysis, photodetection and solar energy harvesting. However, despite very significant experimental effort, a comprehensive theoretical description of the hot carrier generation process is still missing. In this work we develop a theoretical model for the plasmon-i...