Article history: Received 17 August 2009 Received in revised form 13 February 2010 Accepted 24 March 2010 Available online 27 March 2010

It is shown that the encoding/decoding problem for any asynchronous -user discrete memoryless multiple-access channel can be reduced to corresponding problems for at most 2 1 single-user discrete memoryless channels. This result, which extends a similar result for Gaussian channels, reduces the seemingly hard task of finding good multiple-access codes to the much better understood task of findi...

In this paper symbolic-computation methods are used to design simple, fixed-structure, robust controllers for nonlinear systems. Design specifications are reduced to logically quantified polynomial inequalities. The quantifier-elimination (QE) software package QEPCAD is used to eliminate quantifiers on state and plant parameters, to obtain regions of admissible controller parameters, and to gua...

We consider the problem of optimal decentralized controller synthesis. There are several classes of such problems for which effective solution methods are known, including the quadratically invariant one. In this paper, we use Gröbner bases and elimination theory to characterize all closed-loop maps achievable by forming a feedback loop with decentralized controllers. We show that this approach...

large number of applications in physics, chemistry, bilogy, and engineering would greatly benefit from a laser eam that had a sharp focus but, simultaneously, a negliible spreading due to diffraction. Examples of such aplications include laser drilling and writing, trapping nd guiding of microparticles or nanoparticles and neural atoms, precise alignment and metrology echniques, and high-resolu...

Different countries have implemented various methods in their poverty elimination programs. Redistribution policies, financing low income groups, subsidizing, enhancing the capabilities of the poor, and… are among the traditional policies for poverty elimination programs. The study of concept of poverty is always one of the most important considerations in Islamic thoughts. Islamic Shariat wit...