132,247 research outputs found
Structured Review of the Evidence for Effects of Code Duplication on Software Quality
This report presents the detailed steps and results of a structured review of code clone literature. The aim of the review is to investigate the evidence for the claim that code duplication has a negative effect on code changeability. This report contains only the details of the review for which there is not enough place to include them in the companion paper published at a conference (Hordijk, Ponisio et al. 2009 - Harmfulness of Code Duplication - A Structured Review of the Evidence)
Construct redundancy in process modelling grammars: Improving the explanatory power of ontological analysis
Conceptual modelling supports developers and users of information systems in areas of documentation, analysis or system redesign. The ongoing interest in the modelling of business processes has led to a variety of different grammars, raising the question of the quality of these grammars for modelling. An established way of evaluating the quality of a modelling grammar is by means of an ontological analysis, which can determine the extent to which grammars contain construct deficit, overload, excess or redundancy. While several studies have shown the relevance of most of these criteria, predictions about construct redundancy have yielded inconsistent results in the past, with some studies suggesting that redundancy may even be beneficial for modelling in practice. In this paper we seek to contribute to clarifying the concept of construct redundancy by introducing a revision to the ontological analysis method. Based on the concept of inheritance we propose an approach that distinguishes between specialized and distinct construct redundancy. We demonstrate the potential explanatory power of the revised method by reviewing and clarifying previous results found in the literature
The impact of diversity upon common mode failures
Recent models for the failure behaviour of systems involving redundancy and diversity have shown that common mode failures can be accounted for in terms of the variability of the failure probability of components over operational environments. Whenever such variability is present, we can expect that the overall system reliability will be less than we could have expected if the components could have been assumed to fail independently. We generalise a model of hardware redundancy due to Hughes [Hughes 1987], and show that with forced diversity, this unwelcome result no longer applies: in fact it becomes theoretically possible to do better than would be the case under independence of failures
The Hush Cryptosystem
In this paper we describe a new cryptosystem we call "The Hush Cryptosystem"
for hiding encrypted data in innocent Arabic sentences. The main purpose of
this cryptosystem is to fool observer-supporting software into thinking that
the encrypted data is not encrypted at all. We employ a modified Word
Substitution Method known as the Grammatical Substitution Method in our
cryptosystem. We also make use of Hidden Markov Models. We test our
cryptosystem using a computer program written in the Java Programming Language.
Finally, we test the output of our cryptosystem using statistical tests.Comment: 7 pages. 5 figures. Appeared in the 2nd International Conference on
Security of Information and Networks (SIN 2009), North Cyprus, Turkey;
Proceedings of the 2nd International Conference on Security of Information
and Networks (SIN 2009), North Cyprus, Turke
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