880 research outputs found
Incremental Recompilation of Knowledge
Approximating a general formula from above and below by Horn formulas (its
Horn envelope and Horn core, respectively) was proposed by Selman and Kautz
(1991, 1996) as a form of ``knowledge compilation,'' supporting rapid
approximate reasoning; on the negative side, this scheme is static in that it
supports no updates, and has certain complexity drawbacks pointed out by
Kavvadias, Papadimitriou and Sideri (1993). On the other hand, the many
frameworks and schemes proposed in the literature for theory update and
revision are plagued by serious complexity-theoretic impediments, even in the
Horn case, as was pointed out by Eiter and Gottlob (1992), and is further
demonstrated in the present paper. More fundamentally, these schemes are not
inductive, in that they may lose in a single update any positive properties of
the represented sets of formulas (small size, Horn structure, etc.). In this
paper we propose a new scheme, incremental recompilation, which combines Horn
approximation and model-based updates; this scheme is inductive and very
efficient, free of the problems facing its constituents. A set of formulas is
represented by an upper and lower Horn approximation. To update, we replace the
upper Horn formula by the Horn envelope of its minimum-change update, and
similarly the lower one by the Horn core of its update; the key fact which
enables this scheme is that Horn envelopes and cores are easy to compute when
the underlying formula is the result of a minimum-change update of a Horn
formula by a clause. We conjecture that efficient algorithms are possible for
more complex updates.Comment: See http://www.jair.org/ for any accompanying file
PCG: A prototype incremental compilation facility for the SAGA environment, appendix F
A programming environment supports the activity of developing and maintaining software. New environments provide language-oriented tools such as syntax-directed editors, whose usefulness is enhanced because they embody language-specific knowledge. When syntactic and semantic analysis occur early in the cycle of program production, that is, during editing, the use of a standard compiler is inefficient, for it must re-analyze the program before generating code. Likewise, it is inefficient to recompile an entire file, when the editor can determine that only portions of it need updating. The pcg, or Pascal code generation, facility described here generates code directly from the syntax trees produced by the SAGA syntax directed Pascal editor. By preserving the intermediate code used in the previous compilation, it can limit recompilation to the routines actually modified by editing
SAGA: A project to automate the management of software production systems
The SAGA system is a software environment that is designed to support most of the software development activities that occur in a software lifecycle. The system can be configured to support specific software development applications using given programming languages, tools, and methodologies. Meta-tools are provided to ease configuration. The SAGA system consists of a small number of software components that are adapted by the meta-tools into specific tools for use in the software development application. The modules are design so that the meta-tools can construct an environment which is both integrated and flexible. The SAGA project is documented in several papers which are presented
An evaluation of Ada for Al applications
Expert system technology seems to be the most promising type of Artificial Intelligence (AI) application for Ada. An expert system implemented with an expert system shell provides a highly structured approach that fits well with the structured approach found in Ada systems. The current commercial expert system shells use Lisp. In this highly structured situation a shell could be built that used Ada just as well. On the other hand, if it is necessary to deal with some AI problems that are not suited to expert systems, the use of Ada becomes more problematical. Ada was not designed as an AI development language, and is not suited to that. It is possible that an application developed in say, Common Lisp could be translated to Ada for actual use in a particular application, but this could be difficult. Some standard Ada packages could be developed to make such a translation easier. If the most general AI programs need to be dealt with, a Common Lisp system integrated with the Ada Environment is probably necessary. Aside from problems with language features, Ada, by itself, is not well suited to the prototyping and incremental development that is well supported by Lisp
Evolution of Ada technology in the flight dynamics area: Implementation/testing phase analysis
An analysis is presented of the software engineering issues related to the use of Ada for the implementation and system testing phases of four Ada projects developed in the flight dynamics area. These projects reflect an evolving understanding of more effective use of Ada features. In addition, the testing methodology used on these projects has changed substantially from that used on previous FORTRAN projects
A model for inter-module analysis and optimizing compilation
Recent research into the implementation of logic programming
languages has demonstrated that global program analysis can be used to speed up execution by an order of magnitude. However, currently such global program analysis requires the program to be analysed as a whole: sepárate compilation of modules is not supported. We describe and empirically evalúate a simple model for extending global program
analysis to support sepárate compilation of modules. Importantly, our model supports context-sensitive program analysis and multi-variant specialization of procedures in the modules
Minimum Hardware Requirements for Hybrid Quantum-Classical DMFT
We numerically emulate noisy intermediate-scale quantum (NISQ) devices and
determine the minimal hardware requirements for two-site hybrid
quantum-classical dynamical mean-field theory (DMFT). We develop a circuit
recompilation algorithm which significantly reduces the number of quantum gates
of the DMFT algorithm and find that the quantum-classical algorithm converges
if the two-qubit gate fidelities are larger than 99%. The converged results
agree with the exact solution within 10%, and perfect agreement within
noise-induced error margins can be obtained for two-qubit gate fidelities
exceeding 99.9%. By comparison, the quantum-classical algorithm without circuit
recompilation requires a two-qubit gate fidelity of at least 99.999% to achieve
perfect agreement with the exact solution. We thus find quantum-classical DMFT
calculations can be run on the next generation of NISQ devices if combined with
the recompilation techniques developed in this work.Comment: 10 pages, 9 figures, 1 table. Updated with minor corrections for
publicatio
Ground Systems Development Environment (GSDE) software configuration management
This report presents a review of the software configuration management (CM) plans developed for the Space Station Training Facility (SSTF) and the Space Station Control Center. The scope of the CM assessed in this report is the Systems Integration and Testing Phase of the Ground Systems development life cycle. This is the period following coding and unit test and preceding delivery to operational use. This report is one of a series from a study of the interfaces among the Ground Systems Development Environment (GSDE), the development systems for the SSTF and the SSCC, and the target systems for SSCC and SSTF. This is the last report in the series. The focus of this report is on the CM plans developed by the contractors for the Mission Systems Contract (MSC) and the Training Systems Contract (TSC). CM requirements are summarized and described in terms of operational software development. The software workflows proposed in the TSC and MSC plans are reviewed in this context, and evaluated against the CM requirements defined in earlier study reports. Recommendations are made to improve the effectiveness of CM while minimizing its impact on the developers
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