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Querying graph databases using a functional language extended with second order facilities 14th

Proceedings of the 1996 14th British National conference on Databases, BNCOD 14

作者： Ayres, Robert King, Peter J.H. Department of Computer Science and Information Systems Brunel University Uxbridge Middlessex UB8 3PH United Kingdom Department of Computer Science Birkbeck College University of London Malet Street London WC1E 7HX United Kingdom

ISBN: (纸本)9783540614425

this paper presents the functional database language Hydra which extends previous such languages with associational facilities enabling a user to pose queries about the ways in which values and entities in the database are related to each other. these associational facilities work by treating the database as a graph and following all the arcs from a node or finding paths between nodes. the nodes of the database graph correspond to entities or values in the application domain and the arcs to associations between those entities and values. From the perspective of Hydra this database graph is viewed in terms of functions between sets of entities and values. Associational facilities are provided by built-in second-order primitives which use schema-level information to determine what arcs may be associated with a node or as the basis for searching for an instance-level path. Results from associational primitives are returned in the form of lists of functions which may be displayed to the user or directly applied to other parameters. the associational facilities provided are fully integrated into a computationally complete language in the style of Miranda. this integration allows complex queries to be answered, which are beyond the power of conventional database query languages. © Springer-Verlag Berlin Heidelberg 1996.

关键词： functional databases functional programming Graph-databases Semantic networks

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A replication technique based on a functional and attribute grammar computation model

A replication technique based on a functional and attribute ...

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international Symposium on Software Reliability Engineering (ISSRE)

作者： A. Cherif M. Suzuki T. Katayama Japan Advanced Institute of Science and Technology Tatsunokuchi Japan

Presents a replication technique based on the FTAG (fault-tolerant attribute grammar) computation model, where instances of a replicated application are active on different groups of processors called replicas. FTAG is a functional and attribute-based model. the developed replication technique implements "active parallel replication", i.e. all replicas are active and concurrently compute a different piece of the application's parallel code. In our model, replicas cooperate not only to detect and mask failures but also to perform parallel computation. the replication mechanisms are supported by the FTAG run-time system and are fully application-transparent. Different novel mechanisms for checkpointing and recovery are developed. Rollback is achieved only if the system experiences multiple failures, otherwise forward recovery is performed. the replication technique takes full advantage of parallel computation to reduce the computation time.

关键词： Computational modeling Fault tolerance Concurrent computing Checkpointing Computer networks Distributed computing Redundancy functional programming Communication networks Inspection

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Integrity checking for nested transactions

Integrity checking for nested transactions

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international Workshop on Database and Expert Systems Applications

作者： B. Defude H. Martin Institut National de Télécommunications Evry France IMAG-Campus Laboratoire de Génie Informatique Grenoble France

the authors present a mechanism to specify and to validate consistency constraints in object oriented databases. Constraints are specified using preand post-conditions associated with an exception handling mechanism. During transaction run-time, they treat exceptions corresponding to errors (in this case, they use immediate exceptions which are processed immediately) or presumption of errors (in this case, they use deferred exceptions which are processed at the end of the transaction), in order to insure validation. To refine their mechanism, we enlarge it to nested transactions. Deferred exceptions can be processed at each node of the transaction tree. Using a predefined exception, they propagate an abort of a sub-transaction to its parent transaction. thus, the parent transaction can choose among different policies for processing the sub-transaction abort.

关键词： Object oriented modeling Object oriented databases Transaction databases Object oriented programming Computer languages Runtime Writing programming profession

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thread scheduling for cache locality

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Computer architecture news 1996年第SPECIAL ISSU期24卷 60-71页

作者： Philbin, J. Edler, J. Anshus, O.J. Douglas, C.C. Li, K. NEC Research Inst Princeton NJ United States

this paper describes a method to improve the cache locality of sequential programs by scheduling fine-grained threads. the algorithm relies upon hints provided at the time of thread creation to determine a thread execution order likely to reduce cache misses. this technique may be particularly valuable when compiler-directed tiling is not feasible. Experiments with several application programs, on two systems with different cache structures, show that our thread scheduling method can improve program performance by reducing second-level cache misses.

关键词： Computer programming

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Truly concurrent constraint programming 7th

Truly concurrent constraint programming

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7th international conference on Concurrency theory, CONCUR 1996

作者： Gupta, Vineet Jagadeesan, Radha Saraswat, Vijay Xerox PARC 3333 Coyote Hill Road Palo AltoCA94304 United States Dept. of Mathematical Sciences Loyola University-Lake Shore Campus ChicagoIL60626 United States

ISBN: (纸本)9783540616047

Concurrent Constraint Prograrnming (CCP) is a powerful computation model for concurrency obtained by internalizing the notion of computation via deduction over (first-order) systems of partial information (constraints). In [SRP91] a semantics for indeterminate CCP was given via sets of bounded trace operators;this was shown to be fully abstract with respect to observing all possible quiescent stores (= final states) of the computation. Bounded trace operators constitute a certain class of (finitary) "invertible" closure operators over a downward closed sublattice. theycanbethoughtofasgeneratedviathegrammar: t::= c[ c → t ] cat where c ranges over primitive constraints, ⋀ is conjunction and → intuitionistic implication. We motivate why it is interesting to consider as observable a "causality" relation on the store: what is observed is not just the conjunction of constraints deposited in the store, but also the causal dependencies between these constraints – what constraints were required to be present in the computation before others could be generated. We show that the same construction used to give the "interleaving" semantics in [SRP91] can be used to give a true-concurrency semantics provided that denotations are taken to be sets of bounded closure operators, which can be generated via the grammar. © Springer-Verlag Berlin Heidelberg 1996.

关键词： Semantics

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Classifying software process models based on natural language descriptions

Classifying software process models based on natural languag...

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international Workshop on Database and Expert Systems Applications

作者： E. Ellmer D. Merkl Department of Information Engineering University of Technology Vienna Vienna Austria Department of Software Technology University of Technology Vienna Vienna Austria

Reuse of the valuable knowledge gained through the realization of software projects is an important step in overcoming well-known problems of the software industry such as wrong schedules and cost estimations, low productivity, and low product quality. To promote this kind of reuse the authors propose an approach relying on an explicit representation of the software processes by process descriptions and to organize and classify them in a software process library for further use within software projects. A process description is divided into an informal process definition document and a formal process model. the process definition document constitutes the basis for the classification process that is performed by using an artificial neural network. they present an exposition of their approach and discuss the promising results of a case study in structuring a software process library.

关键词： Natural languages Capability maturity model Software libraries programming Software quality Costs Productivity Software reusability Job shop scheduling Software engineering

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the ROL deductive object base language

The ROL deductive object base language

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international Workshop on Database and Expert Systems Applications

作者： M. Liu Department of Computer Science University of Regina Regina SAS Canada

the paper presents a novel deductive object base language, called ROL (Rule-based Object Language), which has been implemented at the University of Regina (Canada) and is available via anonymous ftp. It effectively integrates important features of object oriented databases and deductive databases into a uniform framework. It supports object oriented features such as object identity, complex objects, classes, class hierarchy, multiple inheritance, and schema. It also supports structured values such as functor objects and sets, treats them as first class citizens, and provides powerful mechanisms for representing both partial and complete information on sets. It is an extension of pure valued oriented deductive languages such as Datalog and LDL (without grouping) and subsumes them as special cases. Furthermore, it has a logical semantics that cleanly accounts for all of its object oriented and value oriented features.

关键词： Deductive databases Object oriented databases Spatial databases Object oriented modeling Database languages Computer science Identity management systems Computer languages Data models Logic programming

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Processing deductions in an active fashion

Processing deductions in an active fashion

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international Workshop on Database and Expert Systems Applications

作者： M.S. Desouki A. Simonet M. Simonet Faculteé de Mé'decine de Grenoble Laboratoire TIMC-IMAG La Tronche France

Active and deductive rules in databases and procedural attachment in knowledge bases are used as mechanisms of computation of derived attributes. these research domains have become very closely related. the support of derivations in current active databases suffers from many semantic and technical problems. Active rules in their ECA (Event Condition Action) form are event oriented whereas derivations are naturally data oriented. Deductive rules are well adapted to relational databases, but their integration within the object oriented model does not always have successful results. Procedural attachment may be considered as both a deductive and active process, but it uses an imperative language to derive attributes. We try to focus on the use of active rules to derive attributes in an object oriented model. We give our approach for the support of deductions in a declarative assertion language and their processing in an active way. We propose a declarative derivation approach integrated within an object oriented model.

关键词： Relational databases Object oriented databases Object oriented modeling Deductive databases Logic programming Production Testing Artificial intelligence Expert systems Impedance

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Structure and performance of interpreters

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Computer architecture news 1996年第SPECIAL ISSU期24卷 150-159页

作者： Romer, T.H. Lee, D. Voelker, G.M. Wolman, A. Wong, W.A. Baer, J.-L. Bershad, B.N. Levy, H.M. Univ of Washington Seattle WA United States

Interpreted languages have become increasingly popular due to demands for rapid program development, ease of use, portability, and safety. Beyond the general impression that they are ″slow″, however, little has been documented about the performance of interpreters as a class of applications. this paper examines interpreter performance by measuring and analyzing interpreters from both software and hardware perspectives. As examples, we measure the MIPSI, Java, Perl, and Tcl interpreters running as array of micro and macro benchmarks on a DEC Alpha platform. Our measurements of these interpreters relate performance to the complexity of the interpreter's virtual machine and demonstrate that native runtime libraries can play a key role in providing good performance. From an architecture perspective, we show that interpreter performance is primarily a function of the interpreter itself and is relatively independent of the application being interpreted. We also demonstrate that high-level interpreters' demands on processor resources are comparable to those of other complex compiled programs, such as gcc. We conclude that interpreters, as a class of applications, do not currently motivate special hardware support for increased performance.

关键词： Computer programming languages

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Whole-program optimization for time and space efficient threads

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Computer architecture news 1996年第SPECIAL ISSU期24卷 50-59页

作者： Grunwald, D. Neves, R. Univ of Colorado Boulder CO United States

Modern languages and operating systems often encourage programmers to use threads, or independent control streams, to mask the overhead of some operations and simplify program structure. Multitasking operating systems use threads to mask communication latency, either with hardwares devices or users. Client-server applications typically use threads to simplify the complex control-flow that arises when multiple clients are used. Recently, the scientific computing community has started using threads to mask network communication latency in massively parallel architectures, allowing computation and communication to be overlapped. Lastly, some architectures implement threads in hardware, using those threads to tolerate memory latency. In general, it would be desirable if threaded programs could be written to expose the largest degree of parallelism possible, or to simplify the program design. However, threads incur time and space overheads, and programmers often compromise simple designs for performance. In this paper, we show how to reduce time and space thread overhead using control flow and register liveness information inferred after compilation. Our techniques work on binaries, are not specific to a particular compiler or thread library and reduce the overall execution time of fine-grain threaded programs by ≈15-30%. We use execution-driven analysis and an instrumented operating system to show why the execution time is reduced and to indicate areas for future work.

关键词： Computer programming

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