12,927 research outputs found

    The Environment as an Argument

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    Context-awareness as defined in the setting of Ubiquitous Computing [3] is all about expressing the dependency of a specific computation upon some implicit piece of information. The manipulation and expression of such dependencies may thus be neatly encapsulated in a language where computations are first-class values. Perhaps surprisingly however, context-aware programming has not been explored in a functional setting, where first-class computations and higher-order functions are commonplace. In this paper we present an embedded domain-specific language (EDSL) for constructing context-aware applications in the functional programming language Haskell. Ā© 2012 Springer-Verlag

    Combustion Gas Properties I-ASTM Jet a Fuel and Dry Air

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    A series of computations was made to produce the equilibrium temperature and gas composition for ASTM jet A fuel and dry air. The computed tables and figures provide combustion gas property data for pressures from 0.5 to 50 atmospheres and equivalence ratios from 0 to 2.0

    ISO/IEC 15504 measurement applied to COBIT process maturity

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    Purpose: The assessment of COBIT process maturity levels is fraught with a number of problems regarding the objectivity of the assessment results. Unlike ISO/IEC 15504, COBIT does not define an assessment model. The purpose of this paper is to align the behavioural aspects of the six COBIT process attributes with achievement results defined for the nine process attributes associated with the ISO/IEC 15504-2 measurement scale. The authors believe that this alignment permits a translation of the ISO/IEC 15504 assessment data into an objective COBIT process maturity rating. Design/methodology/approach: The tables presented in the paper identify the COBIT process attributes, the applicable ISO/IEC 15504 process attribute achievement results and the aggregated rating that pertains to the selected achievement results. A final table lists the derived COBIT process maturity level in terms of the ratings for the ISO/IEC 15504 process attribute achievement results for an assessed process. Findings: The objectivity of the aggregated result (COBIT process maturity level) appeals strongly to end-users of this measurement result, particularly where contractual obligations must be satisfied. Practical implications: The method is useful where measurement rigour must be demonstrated in the computation of the COBIT process maturity levels. Originality/value: This assessment and computational method was developed and trialled in the second half of 2010 in the context of the assessment of 13 information technology (IT) service management processes at two different customer sites. The material is of special value to service managers in companies that have outsourced IT service management processes to external IT service providers. Ā© Emerald Group Publishing Limited

    Coagulation and fragmentation processes with evolving size and shape profiles : a semigroup approach

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    We investigate a class of bivariate coagulation-fragmentation equations. These equations describe the evolution of a system of particles that are characterised not only by a discrete size variable but also by a shape variable which can be either discrete or continuous. Existence and uniqueness of strong solutions to the associated abstract Cauchy problems are established by using the theory of substochastic semigroups of operators

    Fractional diffusions with time-varying coefficients

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    This paper is concerned with the fractionalized diffusion equations governing the law of the fractional Brownian motion BH(t)B_H(t). We obtain solutions of these equations which are probability laws extending that of BH(t)B_H(t). Our analysis is based on McBride fractional operators generalizing the hyper-Bessel operators LL and converting their fractional power LĪ±L^{\alpha} into Erd\'elyi--Kober fractional integrals. We study also probabilistic properties of the r.v.'s whose distributions satisfy space-time fractional equations involving Caputo and Riesz fractional derivatives. Some results emerging from the analysis of fractional equations with time-varying coefficients have the form of distributions of time-changed r.v.'s

    A principled approach to programming with nested types in Haskell

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    Initial algebra semantics is one of the cornerstones of the theory of modern functional programming languages. For each inductive data type, it provides a Church encoding for that type, a build combinator which constructs data of that type, a fold combinator which encapsulates structured recursion over data of that type, and a fold/build rule which optimises modular programs by eliminating from them data constructed using the buildcombinator, and immediately consumed using the foldcombinator, for that type. It has long been thought that initial algebra semantics is not expressive enough to provide a similar foundation for programming with nested types in Haskell. Specifically, the standard folds derived from initial algebra semantics have been considered too weak to capture commonly occurring patterns of recursion over data of nested types in Haskell, and no build combinators or fold/build rules have until now been defined for nested types. This paper shows that standard folds are, in fact, sufficiently expressive for programming with nested types in Haskell. It also defines buildcombinators and fold/build fusion rules for nested types. It thus shows how initial algebra semantics provides a principled, expressive, and elegant foundation for programming with nested types in Haskell

    INTEGRAL deep observations of the Small Magellanic Cloud

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    Deep observations of the Small Magellanic Cloud (SMC) and region were carried out in the hard X-ray band by the INTEGRAL observatory in 2008-2009. The field of view of the instrument permitted simultaneous coverage of the entire SMC and the eastern end of the Magellanic Bridge. In total, INTEGRAL detected seven sources in the SMC and five in the Magellanic Bridge; the majority of the sources were previously unknown systems. Several of the new sources were detected undergoing bright X- ray outbursts and all the sources exhibited transient behaviour except the supergiant system SMC X-1. They are all thought to be High Mass X-ray Binary (HMXB) systems in which the compact object is a neutron star.Comment: 7 pages, 10 figures Accepted for publication in MNRA
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