this paper describes a refinement-based development method for mobile processes. Process mobility is interpreted as the assignment or communication of higher-order variables, whose values are process constants or para...
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ISBN:
(纸本)3540223800
this paper describes a refinement-based development method for mobile processes. Process mobility is interpreted as the assignment or communication of higher-order variables, whose values are process constants or parameterised processes, in which target variables update their values and source variables lose their values. the mathematical basis for the work is Hoare and He's Unifying theories of programming (UTP). In this paper, we present a set of algebraic laws to be used for the development of mobile systems. the correctness of these laws is ensured by the UTP semantics of mobile processes. We illustrate our theory through a simple example that can be implemented in both a centralised and a distributed way. First, we present the pi-calculus specification for both systems and demonstrate that they are observationally equivalent. Next, we show how the centralised system may be step-wisely developed into the distributed one using our proposed laws.
the efficient representation and manipulation of data is one of the fundamental tasks in the construction of large software systems. Parametric polymorphism has been one of the most successful approaches to date but, ...
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ISBN:
(纸本)3540223800
the efficient representation and manipulation of data is one of the fundamental tasks in the construction of large software systems. Parametric polymorphism has been one of the most successful approaches to date but, as of yet, has not been applicable to programming with quotient datatypes such as unordered pairs, cyclic lists, bags etc. this paper provides the basis for writing polymorphic programs over quotient datatypes by extending our recently developed theory of containers.
We investigate a generalization of weight-constraint programs with stable semantics, as implemented in the ASP solver smodels. Our programs admit atoms of the form (X, F) where X is a finite set of prepositional atoms...
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We investigate a generalization of weight-constraint programs with stable semantics, as implemented in the ASP solver smodels. Our programs admit atoms of the form (X, F) where X is a finite set of prepositional atoms and F is an arbitrary family of subsets of X. We call such atoms set constaints and show that the concept of stable model can be generalized to programs admitting set constraints both in the bodies and the heads of clauses. Natural tools to investigate the fixpoint semantics for such programs are nondeterministic operators in complete lattices. We prove two fixpoint theorems for such operators.
作者：
Ravindran, KSabbir, ACUNY City Coll
Dept Comp Sci New York NY 10031 USA CUNY
Grad Ctr Dept Comp Sci New York NY 10031 USA CUNY
Grad Ctr Dept Comp Sci New York NY 10016 USA
In this paper, we propose a programming model based on 'timed event dissemination' for structuring a distributed real-time multimedia presentation. In this model, event notifications capture program-generated ...
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ISBN:
(纸本)3540232397
In this paper, we propose a programming model based on 'timed event dissemination' for structuring a distributed real-time multimedia presentation. In this model, event notifications capture program-generated actions and/or user-level object accesses on a multimedia window. A coherent effect of these actions requires enforcing deadlines on the event processing over prescribed time intervals. To meet this requirement, the paper advocates an integration of the 'flow of time' as part of the semantics of data presentation on a multimedia window. the paper explores a programming paradigm for event processing: causal ordering of timed messages, to realize multimedia data presentations. this yields simplicity and uniformity in the programming structure of multimedia applications. the presentation specifications in our model can be easily and accurately mapped onto system-level QOS parameters (such as network delays and play-out buffer delays) for scheduling purposes. this in turn may lead to an optimal use of the system resources by a multimedia presentation protocol. the generality of our event-oriented programming interface also allows reducing the multimedia system development costs through software reuse.
In the context of a formal programming methodology and verificationsystem for ownership-based invariants in object-oriented programs, a friendship system is defined. Friendship is a flexible protocol that allows invar...
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the MBS (material basis set) method has been demonstrated in proof of concept studies to be useful for single isotope identification using gamma ray spectra that have been attenuated and distorted by shielding materia...
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ISBN:
(纸本)0894486853
the MBS (material basis set) method has been demonstrated in proof of concept studies to be useful for single isotope identification using gamma ray spectra that have been attenuated and distorted by shielding materials. In porting this method to run on the hand held Palm Pilot CZT Spectrometer, it was determined that the NNLS (non-negative least squares) algorithm previously used to solve this problem on a PC (personal computer) is not fast enough for use on some currently used Palm Pilot models. To rectify this problem, we have developed a fast implementation of NNLS (the precomputed NNLS, or PNNLS method) that significantly reduces the analysis time. In addition, we have evaluated the well-known ART (algebraic reconstruction technique) algorithm for use in this problem. ART is widely used for solving sparse constrained linear systems of equations, such as are encountered in tomographic image reconstruction and certain types of response function fitting. Where ART can be used, it is usually much faster than a constrained least squares fit. A primary problem with computation speed on Palm Pilots is the lack of a floating point coprocessor. Floating point operations in Palm OS must be done by time-consuming emulator library function calls. We coded the PNNLS algorithms in both floating point and fixed point versions in order to explore this issue. Based on benchmarks performed on Palm Pilots and on PCs, we conclude that while ART runs somewhat faster than the NNLS method, the PNNLS algorithm runs many times faster. Moreover, the fixed point PNNLS solvers run approx. six to ten times faster than the floating point versions when no coprocessor is present, or about 40 times faster than the original NNLS algorithm runs without a coprocessor.
Scientific applications contain program sections that exhibit repetitive data accesses. this paper proposes combined compiletime/ runtime data reference analysis techniques that exploit repetitive data access behavior...
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ISBN:
(纸本)9781450377997
Scientific applications contain program sections that exhibit repetitive data accesses. this paper proposes combined compiletime/ runtime data reference analysis techniques that exploit repetitive data access behavior in both regular and irregular program sections. We present a new compiler algorithm to detect such repetitive data references and an API to an underlying software distributed shared memory (software DSM) system to orchestrate the learning and pro-active reuse of communication patterns. We evaluate the combined compile-time/runtime system on a selection of OpenMP applications, exhibiting both regular and irregular data reference patterns, resulting in average performance improvement of 28.1% on 8 processors.
In this paper, we show our initial experience with a class of objects, called Hierarchically Tiled Arrays (HTAs), that encapsulate parallelism. HTAs allow the construction of single-threaded parallel programs where a ...
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ISBN:
(纸本)9781450377997
In this paper, we show our initial experience with a class of objects, called Hierarchically Tiled Arrays (HTAs), that encapsulate parallelism. HTAs allow the construction of single-threaded parallel programs where a master process distributes tasks to be executed by a collection of servers holding the components (tiles) of the HTAs. the tiled and recursive nature of HTAs facilitates the adaptation of the programs that use them to varying machine configurations, and eases the mapping of data and tasks to parallel computers with a hierarchical organization. We have implemented HTAs as a MATLAB™ toolbox, overloading conventional operators and array functions such that HTA operations appear to the programmer as extensions of MATLAB™. Our experiments show that the resulting environment is ideal for the prototyping of parallel algorithms and greatly improves the ease of development of parallel programs while providing reasonable performance.
this paper presents a self-applicable partial evaluator for a considerable subset of full Prolog. the partial evaluator is shown to achieve non-trivial specialisation and be effectively self-applied. the attempts to s...
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