Relaxing goodness is still good

Polygonal hybrid systems (SPDIs) are planar hybrid systems, whose dynamics are defined in terms of constant differential inclusions, one for each of a number of polygonal regions partitioning the plane. The reachability problem for SPDIs is known to be decidable, but depends on the goodnessassumption -- which states that the dynamics do not allow a trajectory to both enter and leave a region through the same edge. In this paper we extend the decidability result to generalised SPDIs(GSPDI), SPDIs not satisfying the goodness assumption, and give an algorithmic solution to decide reachability of such systems.peer-reviewe

A compositional algorithm for parallel model checking of polygonal hybrid systems

The reachability problem as well as the computation of the phase portrait for the class of planar hybrid systems defined by constant differential inclusions (SPDI), has been shown to be decidable. The existing reachability algorithm is based on the exploitation of topological properties of the plane which are used to accelerate certain kind of cycles. The complexity of the algorithm makes the analysis of large systems generally unfeasible. In this paper we present a compositional parallel algorithm for reachability analysis of SPDIs. The parallelization is based on the qualitative information obtained from the phase portrait of an SPDI, in particular the controllability kernel.The United Nations Univ., Int. Inst. for Softw. Technol., Macau,Tunisian Ministry of Higher Education,University of New South Wales, UKpeer-reviewe

Automatic conflict detection on contracts

Partially supported by the Nordunet3 project COSoDIS: “Contract-Oriented Software Development for Internet Services”.Many software applications are based on collaborating, yet competing, agents or virtual organisations exchanging services. Contracts, expressing obligations, permissions and prohibitions of the different actors, can be used to protect the interests of the organisations engaged in such service exchange. However, the potentially dynamic composition of services with different contracts, and the combination of service contracts with local contracts can give rise to unexpected conflicts, exposing the need for automatic techniques for contract analysis. In this paper we look at automatic analysis techniques for contracts written in the contract language CL. We present a trace semantics of CL suitable for conflict analysis, and a decision procedure for detecting conflicts (together with its proof of soundness, completeness and termination). We also discuss its implementation and look into the applications of the contract analysis approach we present. These techniques are applied to a small case study of an airline check-in desk.peer-reviewe

A dilemma resolved? Towards a revised philosophy of conservation education

The guidelines for conservation education agreed by the European Confederation of Conservator-restorers’ Organisations’ state that “The only reasonable way of training in conservation/restoration is full time at university level or at an equivalent level, including practical internships.” Furthermore the September 1994 ECCO guidelines stipulated “Aptitude for the field of conservation/restoration should be determined by an entrance examination. The education should not take less than three years and preferably consist of four years”. Yet, in early 2000, an authoritative article entitled the “Dilemma of Conservation Education” asked a number of fundamental questions, including one which may be summarized as “Are we expecting a conservator-restorer to learn more than is humanly possible?”. This paper responds to some of these questions, tracing the development of conservation education from one which originated in a multi-disciplinary context to the concept of an interdisciplinary education which underlies the new courses being offered in Malta and a number of other countries. Specifically it will suggest that 1) the objective of conservation education is to create the conservator as an interdisciplinary member of a multi-disciplinary team and 2) rigorous training, a commitment to a shared vision, a deliberately formed and carefully cultivated interdisciplinarity, are the defining characteristics of a true conservator.peer-reviewe

IJGO at the FIGO 2012 Congress and beyond

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135399/1/ijgo1.pd