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.

Integrating Event-B Modelling and Discrete-Event Simulation to Analyse Resilience of Data Stores in the Cloud

Abstract: Ensuring resilience of large data stores in the cloud is a challenging engineering issue It requires the development techniques that allow the designers to predict the main resilience characteristics — fault tolerance and performance — at the early design stages In this paper, we experiment with integrating Event-B modelling with discrete-event simulation Event-B allows us to reason about correctness and data integrity properties of data stores, while discrete-event simulation in SimPy enables quantitative assessment of performance and reliability Since testing in a real cloud environment is expensive and time-consuming, the proposed approach offers several benefits in industrial settings

Grouping of PCB assembly jobs in the case of flexible feeder units

Abstract: Change costs between jobs in printed circuit board assembly depend on the number of component change occasions. Component changes are necessary due to the restricted feeder capacity. Grouping assembly jobs decreases the number of setup occasions. The job grouping problem asks for a minimal cardinality grouping. The feeder magazines Tape Magazine and TM-Flex Magazine of MYDATA (cf. MY-9) are examples of this kind of technology, see http://www.mydata.com/ for more information. This paper studies a generalization of the job grouping problem where the feeder unit is capable of holding sub-units, called feeder boxes. There is a limited set of boxes available in an auxiliary storage, and the feeder unit has certain limitations for the feeder boxes it may hold. The task in job grouping problem with boxes (JGP-B) is to group the jobs into a minimal number of groups in such a way that capacity and feeder restrictions are not violated. Exact solving of the JGP-B is restricted to small problem instances only. Severa...

Stimulating power games as a part of systems development

Abstract: The biggest problems of information system development (ISD) are not in the construction of technical artefacts. The real challenges to development are the social and political aspects of change. Imagining new organizational structures is difficult because knowledge about existing structures is often objectified. Furthermore, the power structures of organizations make such imagination more difficult or even forbidden. This paper describes a study in which a prototype of an information systems (IS) development method, called the Labour Game, was evaluated in field experiments. The paper describes the method and demonstrates how it succeeded in shifting the focus of discussions from technical development to issues which typically increased the competence of employees and modified the power structures of the work processes. The paper advocates the use of ‘soft’ methods, which help users and managers to talk about the social structures of work and consequently about different IS requirements in the early phases of systems development.