Cognitive radio sensor networks are one of the kinds of application where cognitive techniques can be adopted and have many potential applications, challenges and future research trends. According to the research surveys, dynamic spectrum access is an important and necessary technology for future cognitive sensor networks. Traditional methods of dynamic spectrum access are based on spectrum hol...

One perspective in communication systems is to increase the spectrum utilization using cognitive radios. A cognitive radio is a network of intelligent co-existing radios which senses the environment to find the available frequency slots, white spaces, or the spectrum holes as noted in Akyildiz et al. (2008); Haykin (2005). Then, it modifies its transmission characteristics to use that particula...

The rapidly developed wireless services and applications have an increasing demand of spectrum resource, which is actually limited. Therefore, how to allocate spectrum resource effectively for network throughput improvement is an urgent issue. Although the utilization of spectrum can be enhanced by link scheduling for spatial reuse, Network Coding (NC) for broadcast transmission, multicast tran...

various concentrations of copper were embedded into silica matrix to xerogel forms using copper source cu(no3)2∙3h2o. the xerogel samples were prepared by hydrolysis and condensation of tetraethyl ortho-silicate (teos) with determination of new molar ratio of the components by the sol-gel method. after ambient drying, the xerogel samples were heated from 60 to 1000˚c at a slow heating rate (50°...

We present a ground based optical transmission spectrum of the inflated sub-Jupiter mass planet WASP-6b. The spectrum was measured in twenty spectral channels from 480 nm to 860nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the IMACS spectrograph on the Baade telescope at Las Campanas Observ...