9,058 research outputs found

    The CIAO Multi-Dialect Compiler and System: An Experimentation Workbench for Future (C)LP Systems

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    CIAO is an advanced programming environment supporting Logic and Constraint programming. It offers a simple concurrent kernel on top of which declarative and non-declarative extensions are added via librarles. Librarles are available for supporting the ISOProlog standard, several constraint domains, functional and higher order programming, concurrent and distributed programming, internet programming, and others. The source language allows declaring properties of predicates via assertions, including types and modes. Such properties are checked at compile-time or at run-time. The compiler and system architecture are designed to natively support modular global analysis, with the two objectives of proving properties in assertions and performing program optimizations, including transparently exploiting parallelism in programs. The purpose of this paper is to report on recent progress made in the context of the CIAO system, with special emphasis on the capabilities of the compiler, the techniques used for supporting such capabilities, and the results in the áreas of program analysis and transformation already obtained with the system

    Space processes for extended low-G testing

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    Results of an investigation of verifying the capabilities of space processes in ground based experiments at low-g periods are presented. Limited time experiments were conducted with the processes. A valid representation of the complete process cycle was achieved at low-g periods ranging from 40 to 390 seconds. A minimum equipment inventory, is defined. A modular equipment design, adopted to assure low cost and high program flexibility, is presented as well as procedures and data established for the synthesis and definition of dedicated and mixed rocket payloads

    Modular Analysis of Distributed Hybrid Systems using Post-Regions (Full Version)

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    We introduce a new approach to analyze distributed hybrid systems by a generalization of rely-guarantee reasoning. First, we give a system for deductive verification of class invariants and method contracts in object-oriented distributed hybrid systems. In a hybrid setting, the object invariant must not only be the post-condition of a method, but also has to hold in the post-region of a method. The post-region describes all reachable states after method termination before another process is guaranteed to run. The system naturally generalizes rely-guarantee reasoning of discrete object-oriented languages to hybrid systems and carries over its modularity to hybrid systems: Only one dL-proof obligation is generated per method. The post-region can be approximated using lightweight analyses and we give a general notion of soundness for such analyses. Post-region based verification is implemented for the Hybrid Active Object language HABS

    Accommodation requirements for microgravity science and applications research on space station

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    Scientific research conducted in the microgravity environment of space represents a unique opportunity to explore and exploit the benefits of materials processing in the virtual abscence of gravity induced forces. NASA has initiated the preliminary design of a permanently manned space station that will support technological advances in process science and stimulate the development of new and improved materials having applications across the commercial spectrum. A study is performed to define from the researchers' perspective, the requirements for laboratory equipment to accommodate microgravity experiments on the space station. The accommodation requirements focus on the microgravity science disciplines including combustion science, electronic materials, metals and alloys, fluids and transport phenomena, glasses and ceramics, and polymer science. User requirements have been identified in eleven research classes, each of which contain an envelope of functional requirements for related experiments having similar characteristics, objectives, and equipment needs. Based on these functional requirements seventeen items of experiment apparatus and twenty items of core supporting equipment have been defined which represent currently identified equipment requirements for a pressurized laboratory module at the initial operating capability of the NASA space station

    An Improved Continuation Call-Based Implementation of Tabling

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    Tabled evaluation has been proved an effective method to improve several aspects of goal-oriented query evaluation, including termination and complexity. Several “native” implementations of tabled evaluation have been developed which offer good performance, but many of them require significant changes to the underlying Prolog implementation, including the compiler and the abstract machine. Approaches based on program transformation, which tend to minimize changes to both the Prolog compiler and the abstract machine, have also been proposed, but they often result in lower efficiency. We explore some techniques aimed at combining the best of these worlds, i.e., developing an extensible implementation which requires minimal modifications to the compiler and the abstract machine, and with reasonably good performance. Our preliminary experiments indicate promising results

    SIRU development. Volume 1: System development

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    A complete description of the development and initial evaluation of the Strapdown Inertial Reference Unit (SIRU) system is reported. System development documents the system mechanization with the analytic formulation for fault detection and isolation processing structure; the hardware redundancy design and the individual modularity features; the computational structure and facilities; and the initial subsystem evaluation results

    Selenoxopropadienylidene (CCCSe) as a bridging ligand

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    The reaction of [W(≡CC≡CSiMe3)(CO)2(Tp*)] (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with [nBu4N]F and selenium in the presence of [RuCl(PPh3)2(η-C5H5)] affords a mixture of the tricarbido complex [WRu(μ-CCC)(CO)2(PPh3)2(η-C5H5)(Tp*)] and the selenoxopropadienylidene (C3Se) complex [WRu(μ-CCCSe)(CO)2(PPh3)2(η-C5H5)(Tp*)], both of which were structurally characterized. The formation of the bimetallic C3Se complex is consistent with the intermediacy of the salt [nBu4N] [W(≡CC≡CSe)(CO)2(Tp*)], which could be observed spectroscopically and computationally interrogated, but not yet isolated.This work was supported by the Australian Research Council (DP130102598 and DP110101611)

    System configuration and executive requirements specifications for reusable shuttle and space station/base

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    System configuration and executive requirements specifications for reusable shuttle and space station/bas

    Biomechanical evaluation of prosthetic feet

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    An evaluation method was developed which can be used generally for the assessment of any prosthetic feet. The two most common prosthetic feet prescribed to below-knee and above-knee amputees are the Uniaxial and SACH feet. A review of prescription practices shows that in the United Kingdom about 80% of the below-knee and above-knee amputees are fitted with a Uniaxial foot, whereas in the United States about 80% are fitted with the SACH foot. These contradictory prescription practices between the two countries, prompted the project to be concentrated on the evaluation of the SACH and Uniaxial feet. The method developed includes a subjective assessment procedure and a biomechanical evaluation on the function of the two prosthetic feet and their effects on whole body gait kinematics and lower limb kinetics. A review of the methods used in gait analysis is presented in the thesis. This forms a basis for the selection of a suitable gait recording system for the project. A background study of lower limb prosthetics in general and a review of prosthetic ankle/foot assemblies in particular are also presented. The methodology and instrumentation used in the project are given. Altogether, six below-knee and five above-knee amputees were tested. Due to insufficient supply of heel bumper stiffness by the manufacturer for the Uniaxial foot, heel bumpers of varying stiffnesses had to be made in the Bioengineering Unit. The development of the analytical procedure for the three-dimensional analysis is presented. A suite of computer programs was written to facilitate the handling of the large amount of data, details of which are included in the Appendix. Results from the analysis of the tests performed are discussed. Although some apparent differences were observed between the SACH and Uniaxial feet, no conclusion can be drawn as to which is better for the function of the amputee.An evaluation method was developed which can be used generally for the assessment of any prosthetic feet. The two most common prosthetic feet prescribed to below-knee and above-knee amputees are the Uniaxial and SACH feet. A review of prescription practices shows that in the United Kingdom about 80% of the below-knee and above-knee amputees are fitted with a Uniaxial foot, whereas in the United States about 80% are fitted with the SACH foot. These contradictory prescription practices between the two countries, prompted the project to be concentrated on the evaluation of the SACH and Uniaxial feet. The method developed includes a subjective assessment procedure and a biomechanical evaluation on the function of the two prosthetic feet and their effects on whole body gait kinematics and lower limb kinetics. A review of the methods used in gait analysis is presented in the thesis. This forms a basis for the selection of a suitable gait recording system for the project. A background study of lower limb prosthetics in general and a review of prosthetic ankle/foot assemblies in particular are also presented. The methodology and instrumentation used in the project are given. Altogether, six below-knee and five above-knee amputees were tested. Due to insufficient supply of heel bumper stiffness by the manufacturer for the Uniaxial foot, heel bumpers of varying stiffnesses had to be made in the Bioengineering Unit. The development of the analytical procedure for the three-dimensional analysis is presented. A suite of computer programs was written to facilitate the handling of the large amount of data, details of which are included in the Appendix. Results from the analysis of the tests performed are discussed. Although some apparent differences were observed between the SACH and Uniaxial feet, no conclusion can be drawn as to which is better for the function of the amputee
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