A flexible multifunctional system based on robot surfacing is established, which consists of four subsystems: central controlling subsystem, 3D laser measuring subsystem, digital gas-shield arc welding subsystem and r...
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A flexible multifunctional system based on robot surfacing is established, which consists of four subsystems: central controlling subsystem, 3D laser measuring subsystem, digital gas-shield arc welding subsystem and robot subsystem. The system can be easily employed to automatic rapid forming or remanufacturing operation, under the control of the central computer by using off-line programming. Test examples on typical parts, shows the system is feasible.
The performance of distributed-memory applications, many of which are written in MPI, critically depends on how well the applications can ameliorate the long latency of data movement by overlapping them with ongoing c...
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ISBN:
(纸本)9781509036530
The performance of distributed-memory applications, many of which are written in MPI, critically depends on how well the applications can ameliorate the long latency of data movement by overlapping them with ongoing computations, thereby minimizing wait time. This paper aims to enable such overlapping in large MPI applications and presents a framework that uses an analytical performance model and an optimizing compiler to systematically enable the optimizations. In particular, we first generate an analytical performance model of the application execution flow to automatically identify potential communication hot spots that may induce long wait time. Next, for each communication hot spot, we search the execution flow graph to find surrounding loops that include sufficient local computation to overlap with the communication. Then, blocking MPI communications are decoupled into nonblocking operations when necessary, and their surrounding loops are transformed to hide the communication latencies behind local computations. We evaluated our framework using 7 MPI applications from the NPB NAS benchmark suite. Our optimizations can attain 3-88% speedup over the original implementations.
Too often, when software is being developed, the software engineers do not sufficiently consider how easy the system will be to use and learn. Following the steps of other related works developed in our research group...
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ISBN:
(纸本)0769508359
Too often, when software is being developed, the software engineers do not sufficiently consider how easy the system will be to use and learn. Following the steps of other related works developed in our research group, this paper deals with the problems of gathering information on the conceptual level about the interface characteristics of the applications that are generated in an automatic way using the OO-Method [12], [13]. The basic idea is to include in the conceptual modelling process both the functionality and interface characteristics for obtaining a complete application that implements the systems modelled using the underlying object-oriented approach. The "OO-Method" is based not only on the object-oriented paradigm but also on the automatic programming paradigm. It combines the advantages of formal specification systems with the practice provided by conventional object-oriented methodologies. After presenting a description of the OO-Method, the core of the paper focuses on how to collect interface information at the conceptual level, using a technique based on the identification of conceptual interface patterns which are independent of any implementation detail. The corresponding extensions to the OO-Method Conceptual Modelling notation that are necessary for modelling interfaces are presented.
There are billions of lines of sequential code inside nowadays software which do not benefit from the parallelism available in modern multicore architectures. Transforming legacy sequential code into a parallel versio...
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ISBN:
(纸本)9783319143132;9783319143125
There are billions of lines of sequential code inside nowadays software which do not benefit from the parallelism available in modern multicore architectures. Transforming legacy sequential code into a parallel version of the same programs is a complex and cumbersome task. Trying to perform such transformation automatically and without the intervention of a developer has been a striking research objective for a long time. This work proposes an elegant way of achieving such a goal. By targeting a task-based runtime which manages execution using a task dependency graph, we developed a translator for sequential JAVA code which generates a highly parallel version of the same program. The translation process interprets the AST nodes for signatures such as read-write access, execution-flow modifications, among others and generates a set of dependencies between executable tasks. This process has been applied to well known problems, such as the recursive Fibonacci and FFT algorithms, resulting in versions capable of maximizing resource usage. For the case of two CPU bounded applications we were able to obtain 10.97x and 9.0x speedup on a 12 core machine.
We present a framework and a methodology to build and analyse automatic provers using the Descente Infinie' induction principle. A stronger connection between different proof techniques like those based on implici...
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ISBN:
(纸本)3540289313
We present a framework and a methodology to build and analyse automatic provers using the Descente Infinie' induction principle. A stronger connection between different proof techniques like those based on implicit induction and saturation is established by uniformly and explicitly representing them as applications of this principle. The framework offers a clear separation between logic and computation, by the means of i) an abstract inference system that defines the maximal sets of induction hypotheses available at every step of a proof, and ii) reasoning modules that perform the computation and allow for modular design of the concrete inference rules. The methodology is applied to define a concrete implicit induction prover and analyse an existing saturation-based inference system.
Programs usually follow many implicit programming rules or patterns, violations of which frequently lead to failures. This thesis proposes a novel approach to statically mine object usage models representing such patt...
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ISBN:
(纸本)9780769528922
Programs usually follow many implicit programming rules or patterns, violations of which frequently lead to failures. This thesis proposes a novel approach to statically mine object usage models representing such patterns for objects used in a program. Additionally, we will describe how object usage models can be used to automatically detect defects, increase program understanding and support programmers by providing code templates. In preliminary experiments the proposed method detected two previously unknown bugs in open source software.
In model-based development, executable specifications (models) are used for the design of the software to be developed. New techniques allow the automatic generation of compact code directly from the model via so-call...
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ISBN:
(纸本)0769520359
In model-based development, executable specifications (models) are used for the design of the software to be developed. New techniques allow the automatic generation of compact code directly from the model via so-called code generators. However, at present, code generators do not possess the same quality characteristics as C or ADA compilers which have been proven in use. The use of test suites, which make it possible to check compilers systematically, is also a promising approach for code generators. This paper describes the design of such a test suite for code generators, and introduces a new testing approach for code generator transformations.
We present a new compilation technique for generating efficient code from synchronous programs. The main idea of our approach consists of computing for each program location an instantaneous statement (called a job) t...
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ISBN:
(纸本)1424404215
We present a new compilation technique for generating efficient code from synchronous programs. The main idea of our approach consists of computing for each program location an instantaneous statement (called a job) that has to be executed whenever the corresponding program location is active. Given the computed jobs, the overall execution scheme is highly flexible, very efficient, but nevertheless very simple: At each instant, it essentially consists of executing the set of active jobs according to their dynamic dependencies. Besides the required outputs, the execution of the jobs additionally yields the set of active threads for tire next instant. As our translation directly follows the structure of tire source code, the correctness of the translation can be easily checked by theorem provers. Furthermore, our translation scheme offers new potential for multi-processor execution, modular compilation, and multi-language code generation.
In this paper we introduce and study a new problem of converting a given 3D shape (or a 2.5D range data) into a bas-relief. The problem can be considered as a geometry counterpart of the HDR image compression problem ...
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ISBN:
(纸本)9780769528151
In this paper we introduce and study a new problem of converting a given 3D shape (or a 2.5D range data) into a bas-relief. The problem can be considered as a geometry counterpart of the HDR image compression problem widely studied in computer graphics. In our approach to the shape bas-reliefing problem, we combine the concepts of mesh saliency, shape exaggerating, and discrete differential coordinates. The final bas-relief has a small width, preserves salient features of the original 3D shape, and, therefore, can be used for shape decorating purposes.
Minimal generators (mingens) of concept intents are valuable elements of the Formal Concept Analysis (FCA) landscape, which are widely used in the database field, for data mining but also for database design purposes....
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ISBN:
(纸本)3540277838
Minimal generators (mingens) of concept intents are valuable elements of the Formal Concept Analysis (FCA) landscape, which are widely used in the database field, for data mining but also for database design purposes. The volatility of many real-world datasets has motivated the study of the evolution in the concept set under various modifications of the initial context. We believe this should be extended to the evolution of mingens. In the present paper, we build up on previous work about the incremental maintenance of the mingen family of a context to investigate the case of lattice merge upon context subposition. We first recall the theory underlying the singleton increment and show how it generalizes to lattice merge. Then we present the design of an effective merge procedure for concepts and mingens together with some preliminary experimental results about its performance.
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