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.

Fair consistency evaluation for reciprocal relations and in group decision making

Abstract: In decision-making processes, it often occurs that the decision maker is asked to pairwise compare alternatives. His/her judgements over a set of pairs of alternatives can be collected into a matrix and some relevant properties, for instance, consistency, can be estimated. Consistency is a desirable property which implies that all the pairwise comparisons respect a principle of transitivity. So far, many indices have been proposed to estimate consistency. Nevertheless, in this paper we argue that most of these indices do not fairly evaluate this property. Then, we introduce a new consistency evaluation method and we propose to use it in group decision making problems in order to fairly weigh the decision maker's preferences according to their consistency. In our analysis, we consider two families of pairwise comparison matrices: additively reciprocal pairwise comparison matrices and multiplicatively reciprocal pairwise comparison matrices.

Verifying invariant based programs in the SOCOS environment

Abstract: An invariant based program is a state transition diagram consisting of nested situations (predicates over program variables) and transitions between situations (predicate transformers). Reasoning about correctness is performed in a local fashion by examining each situation at a time and proving that the situation is satisfied for all possible executions. Since the invariants are in place from the beginning and the verification conditions are easily extracted from the diagram there is no need for complicated proof rules, making invariant diagrams a suitable notation for introducing formal verification to students and programmers. Our preliminary experience from using invariant diagrams in the classroom has prompted the need for a tool to support the method: we introduce here SOCOS, an environment for invariant based programming. SOCOS generates correctness conditions based on weakest precondition semantics, and the user can attempt to automatically discharge these conditions using the Simplify theorem prover; conditions which were not automatically discharged can be proved interactively in the PVS theorem prover.

Software development and experimentation in an academic environment : The gaudi experience

Abstract: In this article, we describe an approach to empirical software engineering based on a combined software factory and software laboratory. The software factory develops software required by an external customer while the software laboratory monitors and improves the processes and methods used in the factory. We have used this approach during a period of four years to define and evaluate a software process that combines practices from Extreme Programming with architectural design and documentation practices in order to find a balance between agility, maintainability and reliability.

C++ Function Object Binders Made Easy

Abstract: A novel argument binding mechanism that can be used with STL algorithm invocations is proposed. Without using any adaptors, binding can be applied directly to pointers to nonmember functions, pointers to const and nonconst member functions and STL function objects. The types and number of arguments in the functions to be bound can be practically arbitrary; argument list lengths up to few dozens of elements can be supported. The unbound arguments are expressed as special placeholders in the argument list; they can appear for any argument position. Hence, binding sites preserve the resemblance to the function prototype of the underlying function, leading to simple and intuitive syntax. Binding can be applied recursively. This results in a versatile function composition mechanism. The binding mechanism is effcient in the sense that it induces very little or no runtime cost.

Contextual Grammars with Distributed Catenation and Shuffle

Abstract: We introduce a new type of contextual grammars. Instead of considering the catenation operation we use the distributed catenation operation. The contexts are distributed catenated with words from the language, defining in this way new words from the language. We investigate several properties of the languages generated by distributed catenated contextual grammars. Finally, we also present the relations to contextual grammars with shuffled contexts and some new results of such grammars.