75,972 research outputs found
Identifying Bugs in Make and JVM-Oriented Builds
Incremental and parallel builds are crucial features of modern build systems.
Parallelism enables fast builds by running independent tasks simultaneously,
while incrementality saves time and computing resources by processing the build
operations that were affected by a particular code change. Writing build
definitions that lead to error-free incremental and parallel builds is a
challenging task. This is mainly because developers are often unable to predict
the effects of build operations on the file system and how different build
operations interact with each other. Faulty build scripts may seriously degrade
the reliability of automated builds, as they cause build failures, and
non-deterministic and incorrect build results.
To reason about arbitrary build executions, we present buildfs, a
generally-applicable model that takes into account the specification (as
declared in build scripts) and the actual behavior (low-level file system
operation) of build operations. We then formally define different types of
faults related to incremental and parallel builds in terms of the conditions
under which a file system operation violates the specification of a build
operation. Our testing approach, which relies on the proposed model, analyzes
the execution of single full build, translates it into buildfs, and uncovers
faults by checking for corresponding violations.
We evaluate the effectiveness, efficiency, and applicability of our approach
by examining hundreds of Make and Gradle projects. Notably, our method is the
first to handle Java-oriented build systems. The results indicate that our
approach is (1) able to uncover several important issues (245 issues found in
45 open-source projects have been confirmed and fixed by the upstream
developers), and (2) orders of magnitude faster than a state-of-the-art tool
for Make builds
Visualizing test diversity to support test optimisation
Diversity has been used as an effective criteria to optimise test suites for
cost-effective testing. Particularly, diversity-based (alternatively referred
to as similarity-based) techniques have the benefit of being generic and
applicable across different Systems Under Test (SUT), and have been used to
automatically select or prioritise large sets of test cases. However, it is a
challenge to feedback diversity information to developers and testers since
results are typically many-dimensional. Furthermore, the generality of
diversity-based approaches makes it harder to choose when and where to apply
them. In this paper we address these challenges by investigating: i) what are
the trade-off in using different sources of diversity (e.g., diversity of test
requirements or test scripts) to optimise large test suites, and ii) how
visualisation of test diversity data can assist testers for test optimisation
and improvement. We perform a case study on three industrial projects and
present quantitative results on the fault detection capabilities and redundancy
levels of different sets of test cases. Our key result is that test similarity
maps, based on pair-wise diversity calculations, helped industrial
practitioners identify issues with their test repositories and decide on
actions to improve. We conclude that the visualisation of diversity information
can assist testers in their maintenance and optimisation activities
BRAHMS: Novel middleware for integrated systems computation
Biological computational modellers are becoming increasingly interested in building large, eclectic models, including components on many different computational substrates, both biological and non-biological. At the same time, the rise of the philosophy of embodied modelling is generating a need to deploy biological models as controllers for robots in real-world environments. Finally, robotics engineers are beginning to find value in seconding biomimetic control strategies for use on practical robots. Together with the ubiquitous desire to make good on past software development effort, these trends are throwing up new challenges of intellectual and technological integration (for example across scales, across disciplines, and even across time) - challenges that are unmet by existing software frameworks. Here, we outline these challenges in detail, and go on to describe a newly developed software framework, BRAHMS. that meets them. BRAHMS is a tool for integrating computational process modules into a viable, computable system: its generality and flexibility facilitate integration across barriers, such as those described above, in a coherent and effective way. We go on to describe several cases where BRAHMS has been successfully deployed in practical situations. We also show excellent performance in comparison with a monolithic development approach. Additional benefits of developing in the framework include source code self-documentation, automatic coarse-grained parallelisation, cross-language integration, data logging, performance monitoring, and will include dynamic load-balancing and 'pause and continue' execution. BRAHMS is built on the nascent, and similarly general purpose, model markup language, SystemML. This will, in future, also facilitate repeatability and accountability (same answers ten years from now), transparent automatic software distribution, and interfacing with other SystemML tools. (C) 2009 Elsevier Ltd. All rights reserved
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Sequence Classification Restricted Boltzmann Machines With Gated Units
For the classification of sequential data, dynamic Bayesian networks and recurrent neural networks (RNNs) are the preferred models. While the former can explicitly model the temporal dependences between the variables, and the latter have the capability of learning representations. The recurrent temporal restricted Boltzmann machine (RTRBM) is a model that combines these two features. However, learning and inference in RTRBMs can be difficult because of the exponential nature of its gradient computations when maximizing log likelihoods. In this article, first, we address this intractability by optimizing a conditional rather than a joint probability distribution when performing sequence classification. This results in the ``sequence classification restricted Boltzmann machine'' (SCRBM). Second, we introduce gated SCRBMs (gSCRBMs), which use an information processing gate, as an integration of SCRBMs with long short-term memory (LSTM) models. In the experiments reported in this article, we evaluate the proposed models on optical character recognition, chunking, and multiresident activity recognition in smart homes. The experimental results show that gSCRBMs achieve the performance comparable to that of the state of the art in all three tasks. gSCRBMs require far fewer parameters in comparison with other recurrent networks with memory gates, in particular, LSTMs and gated recurrent units (GRUs)
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