Inspired by the awarding of the 30th jubilee IEEE medal “for exceptional contributions to information sciences and systems,” this article is dedicated to the memory of Richard W. Hamming, mathematician and computer scientist. If Shannon's mathematical theory of communication, including coding, entropy, and channel capacity, can be assumed as cornerstone of the digital world, error-detecting and error-correcting codes, at the same time, pave the way to its redundancy and reliability. The role of the interaction between human and computer in the world of contemporary communication is considered, together with an emphasis on Hamming's fundamental contributions from information theory to computer technology. Hamming code, Hamming distance, Hamming metric, Hamming window, Hamming numbers, and sphere packing are now standard terms that reflect him as a leader in the development of coding theory. His ideas in coding theory continue to have practical use in computer design.

This article takes a look at the professional accomplishments of Danish scientist Agner Krarup Erlang, who made pioneering contributions in teletraffic theory development.

Service delivery in a heterogeneous wireless environment requires the selection of an optimal radio access network. In order that users could be always connected through the optimal network, it is necessary to develop an adequate model for its selection. This paper presents the proposal of optimal network selection algorithm in wireless heterogeneous environment that is based on TOPSIS method when solving the multicriteria analysis. The wireless networks in this model represent the alternatives, while the network parameters (available bandwidth, quality of service level, security level, data transfer cost) are considered as the criteria for determining the optimal network.