1,895 research outputs found
ChimpCheck: Property-Based Randomized Test Generation for Interactive Apps
We consider the problem of generating relevant execution traces to test rich
interactive applications. Rich interactive applications, such as apps on mobile
platforms, are complex stateful and often distributed systems where
sufficiently exercising the app with user-interaction (UI) event sequences to
expose defects is both hard and time-consuming. In particular, there is a
fundamental tension between brute-force random UI exercising tools, which are
fully-automated but offer low relevance, and UI test scripts, which are manual
but offer high relevance. In this paper, we consider a middle way---enabling a
seamless fusion of scripted and randomized UI testing. This fusion is
prototyped in a testing tool called ChimpCheck for programming, generating, and
executing property-based randomized test cases for Android apps. Our approach
realizes this fusion by offering a high-level, embedded domain-specific
language for defining custom generators of simulated user-interaction event
sequences. What follows is a combinator library built on industrial strength
frameworks for property-based testing (ScalaCheck) and Android testing (Android
JUnit and Espresso) to implement property-based randomized testing for Android
development. Driven by real, reported issues in open source Android apps, we
show, through case studies, how ChimpCheck enables expressing effective testing
patterns in a compact manner.Comment: 20 pages, 21 figures, Symposium on New ideas, New Paradigms, and
Reflections on Programming and Software (Onward!2017
Phase diagrams of a p-Wave superconductor inside a mesoscopic disc-shaped sample
We study the finite-size and boundary effects on a time-reversal-symmetry
breaking p-wave superconducting state in a mesoscopic disc geometry using
Ginzburg-Landau theory. We show that, for a large parameter range, the system
exhibits multiple phase transitions. The superconducting transition from the
normal state can also be reentrant as a function of external magnetic field.Comment: Revised version published in Physical Review
A new engineering approach to predict the long-term hydrostatic strength of unplasticized poly(vinyl chloride) pipes
Extruded polymer pipes are qualified using pressurized pipe tests. With these tests the long-term hydrostatic strength is determined by subjecting the pipes to an internal pressure, while measuring the time-to-failure. Although these tests can be accelerated (at higher temperatures), they remain time consuming and require a spacious experimental setup. To circumvent this costly method a model based approach is proposed by which the long-term hydrostatic strength is predicted. Using short term measurements, the input parameters for this approach can be determined. In this engineering approach the effects of physical aging are included. The approach is capable to quantitatively predict the (long-term) failure time of pipe sections under internal pressure
Exercise training and detraining process affects plasma adiponectin level in healthy and spontaneously hypertensive rats
BACKGROUND: Adiponectin levels with long-term swimming exercise have been never investigated in spontaneously hypertensive rats (SHR). OBJECTIVE: This study was aimed to investigate the effects of exercise and detraining process on the adiponectin plasma levels of spontaneously hypertensive rats (SHR) and healthy Wistar-Kyoto rats (WKY). MATERIAL AND METHODS: The rats in the exercise groups were swimming for 10 weeks, 5 days/week, one hour in a day. The detraining rats were left to be sedentary in their cages for 5 weeks after 10 weeks of exercise period. RESULTS: The plasma adiponectin levels decreased in E and SHRE groups compared to the SC and the SHR groups, respectively. In addition, blood pressure was decreased in the exercise groups vs their controls. The adiponectin level was not found to be significantly different in ED and SHRED groups compared to their controls. The blood pressure did not differ between SDC and ED groups, although in the SHRED group it was found to be lower than in SHRSD group rats. CONCLUSION: The results of this study showed that exercise reduced plasma levels of adiponectin in healthy and spontaneously hypertensive rats. However, this difference disappeared at the end of the training processes. Our results suggest, that changes in plasma adiponectin levels are not responsible for changes in blood pressure
Friction Surface Cladding of AA1050 on AA2024-T351; influence of clad layer thickness and tool rotation rate
Friction Surfacing Cladding (FSC) is a recently developed solid state process to deposit thin metallic clad layers on a substrate. The process employs a rotating tool with a central opening to supply clad material and support the distribution and bonding of the clad material to the substrate. The tool is held at a given distance above the substrate and translates relative to the substrate while the clad material is pressed out and deposited. This work studies the effect of the tool rotation speed and the clad layer thickness on the deposition quality of AA1050 clad layers on top of AA2024-T351 substrates at constant process temperatures. Well bonded, defect free clad layers with uniform thickness and width are produced. A 2D axisymmetric thermal-flow model predicts the influence of the process parameters and confirmed the experimental observations
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