The arbitrarily varying channel models transmission over a channel with an state that can change over time. We may interpret it as a channel with an evil jammer. The arbitrarily varying channel was first introduced by Blackwell, Breiman, and Thomasian in [8]. The wiretap channel models communication with security. It was first introduced by Wyner in [12]. We may interpret it as a channel with a...

The author determines for arbitrarily varying channels a) the average error capacity and b) the maximal error capacity in case of randomized encoding. A formula for the average error capacity in case of randomized encoding was announced several years ago by Dobrushin ([3]). Under a mild regularity condition this formula turns out to be valid and follows as consequence from either a) or b). Sinc...

AbstructFor discrete memoryless channels { LV: X + y } , we consider decoders, possibly suboptimal, which minimize a metric defined additively by a given function d(2. y) 2 0. The largest rate achievable by codes with such a decoder is called the d-capacity C d ( W ) . The choice d ( 2 , y ) = 0 if and only if (iff) LV(yls) > 0 makes Cd(W) equal to the “zero undetected error” or “erasures-only”...

It is well–known that search problems with a stochastic response matrix acting independently for the questions can be equivalently formulated as transmission problems for a discrete memoryless channel (DMC) with feedback. This is explained in Chapter 3 of the book Search Problems by R. Ahlswede and I. Wegener (Wiley 1987, translation of Suchprobleme, Teubner 1979). There also Ahlswede’s coding ...

In this work the arbitrarily varying wiretap channel AVWC is studied. We derive a lower bound on the random code secrecy capacity for the average error criterion and the strong secrecy criterion in the case of a best channel to the eavesdropper by using Ahlswede’s robustification technique for ordinary AVCs. We show that in the case of a non-symmetrisable channel to the legitimate receiver the ...

In this paper, a general solution for torsion of hollow cylinders made of functionally graded materials (FGM) was investigated. The problem was formulated in terms of Prandtl’s stress and, in general, the shear stress and angle of twist were derived. Variations in the material properties such as Young’s modulus and Poisson’s ratio might be arbitrary functions of the radial coordinate. Various m...