The development of a unimodular transformation theory and associated algorithms has renewed interest in FORTRAN DO loops that are not perfectly (or tightly) nested. In this paper we summarize a number of techniques th...
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ISBN:
(纸本)0818666056
The development of a unimodular transformation theory and associated algorithms has renewed interest in FORTRAN DO loops that are not perfectly (or tightly) nested. In this paper we summarize a number of techniques that convert imperfectly nested loops into perfectly nested loops. We examined over 25,000 lines of scientific FORTRAN kernels and benchmarks. Statistics are reported on how often imperfect loops occur and how effective two transformations (scalar forward substitution and loop distribution) are at converting imperfectly nested loops into perfectly nested loops. Further, we describe a compiler that integrates scalar forward substitution, loop distribution, and unimodular transformations while maintaining the basic philosophy of unimodular transformation theory. While our data indicate that imperfectly nested loops still present a problem, the compiler we describe is no more limited by perfectly nested loops than other restructuring compilers available today.
As a new type of wireless network architecture, because of its self-organization, and support multi-hop and heterogeneous networks, Wireless Mesh networks has played an important role in building "wireless cities...
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ISBN:
(纸本)9781424445189
As a new type of wireless network architecture, because of its self-organization, and support multi-hop and heterogeneous networks, Wireless Mesh networks has played an important role in building "wireless cities" and become an research spot in academia and industry. In practical applications, network capacity is the most important need and high network throughput is the most important network performance parameter. As a wireless Mesh network basic issue, network capacity associates the physical characteristics of the network, topology, routing algorithm and channel allocation scheme at all levels. Aiming the question of wireless Mesh network capacity, the paper proposes a hierarchy optimization model from bottom to up and a series of optimization ways based on programming theory. the main content in this paper includes: (1) Optimizing link-channel scheduling strategy, studying the wireless Mesh network channel allocation algorithm, and an interference-based model and linear programming channel allocation and routing joint algorithm is proposed;(2) research of network scalability, taking into account the network coverage and performance at the same time, the paper presents a mixed integer nonlinear programming algorithm for the deployment of the AP;(3) research of gateway deploying strategy, a linear programming based heuristic algorithm gateway deployment is proposed. Research on these issues of network capacity optimization will improve the performance of networks and promote the development of wireless mesh networks;it also has certain significance in the engineering practice.
Context-aware services need to acquire context information from heterogeneous context sources. The diversity of service requirements posts challenges on context provisioning systems as well as their programming models...
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ISBN:
(纸本)9781424477425
Context-aware services need to acquire context information from heterogeneous context sources. The diversity of service requirements posts challenges on context provisioning systems as well as their programming models. This paper proposes COPAL (COntext Provisioning for ALI) - an adaptive approach to context provisioning. COPAL is at first a runtime middleware, which provides loose-coupling between context and its processing. The component architecture of COPAL ensures that new context processing functions can be added dynamically. A set of context processing patterns are proposed to customize context attributes and compose context provisioning schemes. The COPAL components and models are reflected in a Domain Specific Language (DSL), which can further reduce the development efforts of context provisioning using automatic code generation. A motivating scenario is used throughout the paper to illustrate COPAL approach.
Operations research is an applied science, and is widely used in current scientific knowledge and mathematical methods to solve practical problems in modern management and provided the best quantitative basis for deci...
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ISBN:
(纸本)9781424455690
Operations research is an applied science, and is widely used in current scientific knowledge and mathematical methods to solve practical problems in modern management and provided the best quantitative basis for decision-makers. Optimization toolbox extends the capability of the Matlab numeric computing environment. The toolbox includes routines for many types of optimization. This article solves the problem of Operational Research in modern management by using a new software, introduces the application of optimization toolbox in simulation of modern management and gains much better effects. Optimization programs needn't be prepared and design efficiency is greatly improved. At same time, more reliable optimization algorithms are used in optimization toolbox so that the design accuracy is also greatly improved.
We study an extension of the Hindley/Milner system with explicit type scheme annotations and type declarations. The system can express polymorphic function arguments, user-defined data types with abstract components, ...
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ISBN:
(纸本)9780897917698
We study an extension of the Hindley/Milner system with explicit type scheme annotations and type declarations. The system can express polymorphic function arguments, user-defined data types with abstract components, and structure types with polymorphic fields. More generally, all programs of the polymorphic lambda calculus can be encoded by a translation between typing derivations. We show that type reconstruction in this system can be reduced to the decidable problem of first-order unification under a mixed prefix.
One approach to model checking software is based on the abstract-check-refine paradigm: build an abstract model, then check the desired property, and if the check fails, refine the model and start over. We introduce t...
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ISBN:
(纸本)9781581134506
One approach to model checking software is based on the abstract-check-refine paradigm: build an abstract model, then check the desired property, and if the check fails, refine the model and start over. We introduce the concept of lazy abstraction to integrate and optimize the three phases of the abstract-check-refine loop. Lazy abstraction continuously builds and refines a single abstract model on demand, driven by the model checker, so that different parts of the model may exhibit different degrees of precision, namely just enough to verify the desired property. We present an algorithm for model checking safety properties using lazy abstraction and describe an implementation of the algorithm applied to C programs. We also provide sufficient conditions for the termination of the method.
Dynamic typing is a program analysis targeted at removing runtime tagging and untagging operations from programs written in dynamically typed languages. This paper compares dynamic typing with a subtyping system based...
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ISBN:
(纸本)9780897917193
Dynamic typing is a program analysis targeted at removing runtime tagging and untagging operations from programs written in dynamically typed languages. This paper compares dynamic typing with a subtyping system based on set constraints. The purpose is both to make precise the relationship between two superficially unrelated type systems and to illustrate how the advantages of dynamic typing and subtype inference can be combined. The central result is a theorem showing that a typing discipline at least as powerful as dynamic typing can be expressed using set constraints.
In this paper an effective decomposition algorithm for mapping of logic functions onto FPGAs is proposed. The algorithm exploits our symbolic decomposition concept to find FPGA based implementation with a minimal numb...
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ISBN:
(纸本)0818628456
In this paper an effective decomposition algorithm for mapping of logic functions onto FPGAs is proposed. The algorithm exploits our symbolic decomposition concept to find FPGA based implementation with a minimal number of CLBs. Experimental results of the presented method are provided and compared to other similar tools.
The connection between some modularity properties and interpolation is revisited and restated in a general `logic-independent' framework. The presence of uniform interpolants is shown to assist in certain proof ob...
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The connection between some modularity properties and interpolation is revisited and restated in a general `logic-independent' framework. The presence of uniform interpolants is shown to assist in certain proof obligations, which suffice to establish the composition of refinements. The absence of the desirable interpolation properties from many logics that have been used in refinement, motivates a thorough investigation of methods to expand a specification formalism orthogonally, so that the critical uniform interpolants become available. A potential breakthrough is outlined in this paper.
In this paper we present an analysis technique for isolating dead code in higher-order functional programs. First, we formalize what it means for a program fragment to contribute to the value returned by the program. ...
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In this paper we present an analysis technique for isolating dead code in higher-order functional programs. First, we formalize what it means for a program fragment to contribute to the value returned by the program. Next, we provide a purely declarative specification of a subset of terms which constitute dead code. This is done by a refinement of the set-based semantics technique, developed by Nevin Heintze, by the introduction of a concept of demand. We then develop a demand-driven set-based analysis to compute dead code specified by the declarative specification. The demand-driven set-based analysis developed in this paper is polynomial time, in the size of the input program.
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