23,499 research outputs found

    An Introduction to Slice-Based Cohesion and Coupling Metrics

    Get PDF
    This report provides an overview of slice-based software metrics. It brings together information about the development of the metrics from Weiser’s original idea that program slices may be used in the measurement of program complexity, with alternative slice-based measures proposed by other researchers. In particular, it details two aspects of slice-based metric calculation not covered elsewhere in the literature: output variables and worked examples of the calculations. First, output variables are explained, their use explored and standard reference terms and usage proposed. Calculating slice-based metrics requires a clear understanding of ‘output variables’ because they form the basis for extracting the program slices on which the calculations depend. This report includes a survey of the variation in the definition of output variables used by different research groups and suggests standard terms of reference for these variables. Our study identifies four elements which are combined in the definition of output variables. These are the function return value, modified global variables, modified reference parameters and variables printed or otherwise output by the module. Second, slice-based metric calculations are explained with the aid of worked examples, to assist newcomers to the field. Step-by-step calculations of slice-based cohesion and coupling metrics based on the vertices output by the static analysis tool CodeSurfer (R) are presented and compared with line-based calculations

    A Transferable Process Model for E-commerce in SMEs

    Get PDF
    Purpose: The overall objective to this study was the creation of a transferable strategic process model, designed to aid the implementation of e-commerce within UK SMEs. The proposed model seeks to identify and clarify the stages an SME should undertake in order to implement e-commerce more effectively and successfully within its business activities. It is further envisaged that the proposed model will allow the SME to take full advantage of the benefits to e-commerce whilst attempting to minimise or overcome the identified barriers to implementation. Design/Methodology/Approach: A total of 93 postal surveys returned from sample 500 firms; firms selected from Sunday Times Enterprise Network Business Directory and the British Chambers of Commerce Directory. In addition, 22 face-to-face semi-structured interviews were conducted across the UK from this sample examining detailed strategic and implementation issues. Fifty respondents also replied commenting on the strategic process model developed from the research, with a significant majority identifying appropriateness and ease of use. Findings: The responses were selected into two categories; “successful” and “unsuccessful”, based upon a series of strategic e-commerce criteria. Reasons for using e-commerce in the interviews were split between; innovation, natural progression, competitive pressure, the exploitation of opportunity and to a lesser extent; customer service, natural fit and differentiation. Barriers to and benefits of implementation are examined in detail for each interviewee identifying prior research, considering future expansion, considering full integration and the need for thorough planning as key factors in the implementation process. Issues following implementation were also considered as part of the model development process. Implications: The development of a detailed transferable strategic process model for e-commerce implementation amongst SMEs. The model consists of nine phases, with clear and detailed advice for the SME in terms of knowledge acquisition, identification of purpose, competitor analysis, e-commerce strategy formulation, technical delivery, promotional strategy, launch and ongoing development and analysis. Originality/Value: The creation of a transferable strategic process model for e-commerce adoption amongst SMEs, evaluated by SMEs. The transferability analysis conducted here can be considered an indicator as regards the effective use of the model by other small firms within the UK. Key Words: SME, e-commerce, adoption, transferability, process, mode

    Research and development program on magnetic electrical conductor, electrical insulation, and bore seal materials - Electrical conductor and electrical insulation materials topical report

    Get PDF
    Electrical, mechanical, and thermo-physical properties of conductor and insulation materials for application to advanced space electric power system

    Optical constants of uranium plasma Final report

    Get PDF
    Thermodynamic and optical properties of uranium plasma in proposed gaseous core nuclear rocket

    Coating thickness and coverage effects on the forces between silica nanoparticles in water

    Full text link
    The structure and interactions of coated silica nanoparticles have been studied in water using molecular dynamics simulations. For 5 nm diameter amorphous silica nanoparticles we studied the effects of varying the chain length and grafting density of polyethylene oxide (PEO) on the nanoparticle coating's shape and on nanoparticle-nanoparticle effective forces. For short ligands of length n=6n=6 and n=20n=20 repeat units, the coatings are radially symmetric while for longer chains (n=100n=100) the coatings are highly anisotropic. This anisotropy appears to be governed primarily by chain length, with coverage playing a secondary role. For the largest chain lengths considered, the strongly anisotropic shape makes fitting to a simple radial force model impossible. For shorter ligands, where the coatings are isotropic, we found that the force between pairs of nanoparticles is purely repulsive and can be fit to the form (R/2rcore−1)−b(R/2r_\text{core}-1)^{-b} where RR is the separation between the center of the nanoparticles, rcorer_\text{core} is the radius of the silica core, and bb is measured to be between 2.3 and 4.1.Comment: 20 pages, 6 figure

    Use of combinatorial analysis for the study of new material for solar cells applications

    Get PDF
    This paper presents a combinatorial method for the deposition and characterization of new metallic precursors for photovoltaic materials. Onedimensional thin film alloy “libraries” were electrodeposited on Mo-coated glass. The library elements were deposited in two consecutive baths and then heated in a reducing atmosphere to promote interdiffusion of the elements. At the end of this process, the libraries possessed a composition gradient along their lengths, with single elements at their two opposite ends and one or more alloys and/or a solid state solution in between. This continuous range of compositions can therefore be considered a collection of specific precursors that can be interrogated by examining their corresponding locations, with the crystallographic structure along the library changing in accordance with the phase diagram for the metals. The libraries were then sulphurised or selenised by heating in a sulphur-rich or selenium rich atmosphere; this converted the metallic precursors in a continuous range of materials, candidates for potential solar cells absorbers. The libraries were analysed by X-ray diffraction and energy dispersive X-ray spectrometry. The X-ray diffraction results show phase changes across the libraries, which can be correlated with the original precursor concentration at that particular p

    Endomorphisms and automorphisms of locally covariant quantum field theories

    Full text link
    In the framework of locally covariant quantum field theory, a theory is described as a functor from a category of spacetimes to a category of *-algebras. It is proposed that the global gauge group of such a theory can be identified as the group of automorphisms of the defining functor. Consequently, multiplets of fields may be identified at the functorial level. It is shown that locally covariant theories that obey standard assumptions in Minkowski space, including energy compactness, have no proper endomorphisms (i.e., all endomorphisms are automorphisms) and have a compact automorphism group. Further, it is shown how the endomorphisms and automorphisms of a locally covariant theory may, in principle, be classified in any single spacetime. As an example, the endomorphisms and automorphisms of a system of finitely many free scalar fields are completely classified.Comment: v2 45pp, expanded to include additional results; presentation improved and an error corrected. To appear in Rev Math Phy

    Pseudo-Goldstone Boson Effects in Top-Antitop Productions at High Energy Hadron Colliders and Testing Technicolor Models

    Full text link
    We study the top quark pair production process p+p(anti-p)-->top+antitop in various kinds of technicolor (TC) models at the Fermilab Tevatron Run II and the CERN LHC. The s-channel neutral pseudo-Goldstone bosons (PGB's) contribute dominately to the production amplitudes from its coupling to the gluons through the triangle loops of techniquarks and the top quark. Cross sections in different TC models with s-channel PGB contributions are calculated. It is shown that the PGB effects can be experimentally tested and different TC models under consideration can be distinguished at the LHC. Therefore, the p+p-->top+antitop process at the LHC provides feasible tests of the TC models.Comment: 10 pages in RevTex and 4 PS-files for the figures. Paramemter range is changed, and some references are added. Version for publication in Phys. Rev.
    • 

    corecore