1,721,140 research outputs found
Replacement freeness: A criterion for separating process calculi
No full textWe introduce a new criterion to discern the relative expressiveness of process calculi. Intuitively, a calculus is replacement free if replacing a sub-process that cannot perform any visible action by an arbitrary one never affects the capability of the resulting process to perform a visible action. By relying on two slightly different formulations of our criterion we partition the set of process calculi into three classes. Then, we prove that no suitable encodings between any two of such classes exist; hence calculi belonging to different classes have different relative expressiveness. Finally, we classify many well-known variants of the mainstream calculi CCS and the π-calculus, thus demonstrating their expressiveness gaps
A Web-based Tool for Collaborative Access to Scientific Instruments in Cyberinfrastructures
No full textCyberinfrastructures that are being built in the United States and in Europe have the goal of enabling large-scale distributed science and engineering collaborations. However, there is still the need for effective groupware tools that will enable distributed and heterogeneous teams of people to effectively collaborate within these global scenarios. This chapter presents a Web-based groupware tool that is being developed in the context of the GRIDCC European project, whose purpose is to extend current cyberinfrastructures to enable shared access to and control of distributed instrumentation. We discuss the challenges in developing groupware solutions for different social and organizational contexts, and present the main features of a prototype we have designed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Metaklaim: A type safe multi-stage language for global computing
No full textThis paper describes the design and semantics of MetaKlaim, which is a higher order distributed process calculus equipped with staging mechanisms. MetaKlaim integrates MetaML (an extension of SML for multi-stage programming) and Klaim (a Kernel Language for Agents Interaction and Mobility), to permit interleaving of meta-programming activities (such as assembly and linking of code fragments), dynamic checking of security policies at administrative boundaries and ‘traditional’ computational activities on a wide area network (such as remote communication and code mobility). MetaKlaim exploits a powerful type system (including polymorphic types a ́ la system F) to deal with highly parameterised mobile components and to enforce security policies dynamically: types are metadata that are extracted from code at run-time and are used to express trustiness guarantees. The dynamic type checking ensures that the trustiness guarantees of wide area network applications are maintained whenever computations interoperate with potentially untrusted components
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