| 1. |
- Palma, Francis, et al.
(author)
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Investigating the Change-Proneness of Service Patterns and Antipatterns
- 2014
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In: IEEE 7th International Conference on Service-Oriented Computing and Applications, SOCA 2014. - : IEEE. - 9781479968336
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Conference paper (peer-reviewed)abstract
- Like any other software systems, service-based systems (SBSs) evolve frequently to accommodate new user requirements. This evolution may degrade their design and implementation and may cause the introduction of common bad practice solutions - antipatterns - in opposition to patterns which are good solutions to common recurring design problems. We believe that the degradation of the design of SBSs does not only affect the clients of the SBSs but also the maintenance and evolution of the SBSs themselves. This paper presents the results of an empirical study that aimed to quantify the impact of service patterns and antipatterns on the maintenance and evolution of SBSs. We measure the maintenance effort of a service implementation in terms of the number of changes and the size of changes (i.e., Code churns) performed by developers to maintain and evolve the service, two effort metrics that have been widely used in software engineering studies. Using data collected from the evolutionary history of the SBS FraSCAti, we investigate if (1) services involved in patterns require less maintenance effort, (2) services detected as antipatterns require more maintenance effort than other services, and (3) if some particular service antipatterns are more change-prone than others. Results show that (1) services involved in patterns require less maintenance effort, but not at statistically significant level, (2) services detected as antipatterns require significantly more maintenance effort than non-antipattern services, and (3) services detected as God Component, Multi Service, and Service Chain antipatterns are more change-prone (i.e., Require more maintenance effort) than the services involved in other antipatterns. We also analysed the relation between object-oriented code smells and service patterns/antipatterns and found a significant difference in the proportion of code smells contained in the implementations of service patterns and antipatterns.
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| 2. |
- Schael, S., et al.
(author)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
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Research review (peer-reviewed)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 3. |
- Aad, G., et al.
(author)
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- 2012
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swepub:Mat__t (peer-reviewed)
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