Cross-layer approach in cognitive wireless networks is proposed for efficient use of spectrum by detecting primary signals. The detection may be false detection of primary signal, missed detection of primary signal, or correct detection of primary signal. The quick and correct detection of primary signal will be helpful for utilization of the idle spectrum. In the current research, Su’s algorit...

As a growing interest in the cognitive radio technology has been taken based on the idea of opportunistic spectrum use, the spectrum sensing technique for dynamic channel environment is more and more important to ensure that cognitive radios would not interfere with primary systems while it achieves reasonable throughput opportunistically. Architecture based on filter bank allows to sense multi...

Electron tunneling in ferromagnetic single-electron transistors is considered theoretically in the sequential tunneling regime. A new formalism is developed, which operates in a two-dimensional space of states, instead of one-dimensional space used in the spinless case. It is shown that spin fluctuations can be significantly larger than the charge fluctuations. The influence of discrete energy ...

Existing refinement calculi provide frameworks for the stepwise development of imperative programs from specifications. This paper presents a refinement calculus for deriving logic programs. The calculus contains a wide-spectrum logic programming language, including executable constructs such as sequential conjunction, disjunction, and existential quantification, as well as specification constr...

fifty street dust samples were collected from southern and eastern parts of tehran, the capitalof iran. samples were collected during summer under dry and stable weather conditions. total concentrationsof copper (cu), cadmium (cd), lead (pb), chromium (cr), nickel (ni), zinc (zn), iron (fe), manganese (mn)and lithium (li) were determined. ten samples were then selected for characterization, met...

the seasonal abundance patterns of the cotton aphid, aphis gossypii glover, in cotton fields at gorgan in northern iran were studied during two growing seasons of 2002 and 2003. the spatial distribution of different developmental stages and morphs of the aphid was described by fitting data to poisson (random) and negative binomial (aggregated) dis-tributions, and calculating the dispersion indi...

the chemical speciation of heavy metals (arsenic, chromium, copper, lead, zinc and tin) in the sediments offormer tin mining catchment bestari jaya, peninsular malaysia was determined by using the latest version of the community bureau of reference, usually called the bcr 3-step sequential extraction procedure. furthermore, a fourth step was introduced for digestion and analysis of the residue....

knowledge of the probable origin and behaviour of arsenic certainly gives valuable insights into the potential for transfer in the environment and of the risks involved in mining sites. sequential extraction analyses are common experiments often used to study the origin and behaviour of potentially toxic elements. the method, however, presents some deficiencies, including labor-intensive proced...