We describe the design, implementation, and performance of a new system for access control on the web. To achieve greater flexibility in forming access-control policies – in particular, to allow better interoperabili...
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作者：
Gupta, GopalPontelli, EnricoApplied Logic
Programming Languages and Systems Lab. Department of Computer Science University of Texas at Dallas Richardson TX 95083 United States Laboratory for Logic
Databases and Advanced Programming Department of Computer Science New Mexico State University Las Cruces NM 88003 United States
Domain Specific Languages (DSLs) are high level languages designed for solving problems in a particular domain, and have been suggested as means for developing reliable software systems. We present a (constraint) logi...
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Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous objec...
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Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous object-oriented modeling languages. It is bringing about a revolution in this area, based on its ease of use, visual design of models with combination of Lego-like predefined model building blocks, its ability to define model libraries with re-usable components and its support for modeling and simulation of complex applications involving parts from several application domains. In this paper we present the Modelica language with emphasis on its language features and one of the associated simulation environments. Simulation models can be developed in an integrated problem-solving environment by using a graphical editor for connection diagrams. Connections are established just by drawing lines between objects picked from a class library. The principles of object oriented physical systems modeling and the multi-domain capabilities of the language are presented in the paper by several examples.
In this paper we study the use of parallelism to speed up execution of Answer Set Programs (ASP). ASP is an emerging programming paradigm which combines features from constraint programming, logic programming, and non...
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This paper introduces a calculus of weakest specification for supporting reuse of established components in deriving a design (in the sense of formal methods). The weakest specifunction generalizes the notions of weak...
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This paper introduces a calculus of weakest specification for supporting reuse of established components in deriving a design (in the sense of formal methods). The weakest specifunction generalizes the notions of weakest pre-specification and weakest parallel environment;but instead of calculating the weakest required component of a target specification, it calculates the weakest specification function whose value refines the target when applied to an established component. In particular it overcomes the restriction of those other calculi to taking merely one required component at a time. The theory of specifunctions is applied to a new weakest-design calculus in the context of BSP. The calculus is based on the par-seq specifunction which involves two required components: it places one established component in parallel with one required component and the result in sequence with another required component to meet a given specification. A calculus is provided for the par-seq specifunction and it is applied to the derivation of a distributed BSP algorithm for greatest common divisor.
This paper discusses the problem of risk in optimistic simulation protocols, using as an example, simulation of a distributed mutual exclusion protocol with strong consistency properties. The simulation model is augme...
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ISBN:
(纸本)076951104X
This paper discusses the problem of risk in optimistic simulation protocols, using as an example, simulation of a distributed mutual exclusion protocol with strong consistency properties. The simulation model is augmented to detect model inconsistency errors resulting from risky optimistic simulation. While the model runs sequentially without consistency errors, errors occur when the model is executed in parallel optimistically. Some of the errors entirely violate the fundamental mutual exclusion properties of the model itself. To address this problem, we extend the optimistic simulation library to eliminate these inconsistencies. We discuss the details of these extensions and the performance tradeoff for adding them.
As concurrent software systems become larger, the interaction of their components is becoming more complex. This interaction may limit reuse, making it difficult to validate design and correctness and perhaps forcing ...
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ISBN:
(纸本)0769510809
As concurrent software systems become larger, the interaction of their components is becoming more complex. This interaction may limit reuse, making it difficult to validate design and correctness and perhaps forcing reengineering of these systems in order to meet future requirements. In order to reduce this complexity and to build stable and adaptable concurrent software systems, we present an approach that emphasizes the separation of interaction components from the functional components.
Dominance constraints are logical tree descriptions originating from automata theory that have multiple applications in computational linguistics. The satisfiability problem of dominance constraints is NP-complete. In...
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This paper presents linguistic primitives for publish/subscribe programming using events and objects. We integrate our primitives into a strongly typed object-oriented language through four mechnisms: (1) serializatio...
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ISBN:
(纸本)1581133359
This paper presents linguistic primitives for publish/subscribe programming using events and objects. We integrate our primitives into a strongly typed object-oriented language through four mechnisms: (1) serialization, (2) multiple subtyping, (3)closures, and (4) deferred code evaluation. We illustrate our primitives through Java, showing how we have overcome its respective lacks. A precompiler transforms statements based on our publish/subscribe primitives into calls to specifically generated typed adapters, which resemble the typed stubs and skeletons by the rmic precompiler for remote method invocations in Java
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