Turku Centre for Computer Science

About: Turku Centre for Computer Science is a facility organization based out in Turku, Finland. It is known for research contribution in the topics: Decidability & Word (group theory). The organization has 382 authors who have published 1027 publications receiving 19560 citations.

Quantum information: a tutorial

Abstract: Information processing, information transmission, and information security are everyday notions of modern society. But what exactly is information? This seems to be quite a hard question. Analogous complication arises in physical sciences when asking what exactly energy is. A naive approach to define information is to define information as a message contained in a string of symbols, but naturally enough, a similar question about the meaning of “message” arises. In this presentation all potential societal and qualitative connotations of information are stripped away and we will restrict only to the quantitative mathematical aspects of information.

On the nature of supply chain management projects and how to manage them

Abstract: This paper explores the nature of complexity in Supply Chain Management (SCM) projects. We find three aspects to be critical in SCM projects: SCM business processes, information systems, and organizations (internal and external). We also argue that in essence, SCM projects are complex, demonstrating structural complexity, uncertainty, and interdependence between elements, all in a unique context. With this analysis in mind, we look at how established project management methodologies are suited to manage SCM projects. Correspondingly, we investigate the nature of agile project management methods and look at whether these are suitable in an SCM context. Secondary data on previous large-scale SCM projects are used to illustrate the nature of complexity in these projects and whether this could have had an effect on the outcome of the project.

Improved bounds on binary identifying codes

Abstract: The concept of identifying codes was introduced by Karpovsky, Chakrabarty and Levitin in 1998. Their motivation for identification came from finding malfunctioning processors in multiprocessor systems. Besides that identifying codes can also be applied to sensor networks. In this paper we consider identifying codes in Hamming spaces. We first concentrate on improving the lower bounds on codes which identify words within distance r > 1. These improvements are achieved using a new approach. Then we proceed by introducing new lower bounds on codes identifying sets of words. Constructions for such codes with the best known cardinalities are also given.

On automatic infinite permutations

Abstract: An infinite permutation $\alpha$ is a linear ordering of $\mathbb N$ We study properties of infinite permutations analogous to those of infinite words, and show some resemblances and some differences between permutations and words In this paper, we try to extend to permutations the notion of automaticity As we shall show, the standard definitions which are equivalent in the case of words are not equivalent in the context of permutations We investigate the relationships between these definitions and prove that they constitute a chain of inclusions We also construct and study an automaton generating the Thue-Morse permutation