Spectrum-Based Fault Localization for Diagnosing Concurrency Faults

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Concurrency faults are activated by specific thread interleavings at runtime. Traditional fault localization techniques and static analysis fall short to diagnose these faults efficiently. Existing dynamic fault-localization techniques focus on pinpointing data-access patterns that are subject to concurrency faults. In this paper, we propose a spectrum-based fault localization technique for localizing faulty code blocks instead. We systematically instrument the program to create versions that run in particular combinations of thread interleavings. We run tests on all these versions and utilize spectrum-based fault localization to correlate detected errors with concurrently executing code blocks. We have implemented a tool and applied our approach on several industrial case studies. Case studies show that our approach can effectively and efficiently localize concurrency faults

Relationships between unoccupied classroom acoustical conditions and elementary student achievement measured in eastern Nebraska

Building standards recommend maximum background noise levels (BNL) and reverberation times (RT) for unoccupied classrooms. However, existing research does not show a consistent correlation between these parameters and student achievement. Through in situ testing, this research seeks to determine what acoustical conditions should be attained in elementary schools for students to meet educational goals. Acoustical measurements were conducted in a Nebraska public school system and correlated to achievement scores from students in the surveyed classrooms. Unoccupied BNLs and RTs were gathered in 34 third and 33 fifth-grade classrooms. Additionally, binaural room impulse response measurements were gathered in a subset of the classrooms. The results suggest that student reading and language subject areas may be negatively impacted by higher unoccupied BNLs; to meet the upper half of NE state targets, these levels should be less than 45 dBA. However, the percentage of students receiving free or reduced price lunches is more strongly correlated to achievement than BNLs, and the negative correlations between noise and achievement are not significant when controlling for this demographic variable. One statistically significant relationship that remained when controlling for demographics was that classrooms with lower distortion of frequency-smoothed magnitude values generally had students with higher language scores

Journal of Neuroscience Methods 159 (2007) 158–169 Computation of gaze orientation under unrestrained head movements

Given the high relevance of visual input to human behavior, it is often important to precisely monitor the spatial orientation of the visual axis. One popular and accurate technique for measuring gaze orientation is based on the dual search coil. This technique does not allow for very large displacements of the subject, however, and is not robust with respect to translations of the head. More recently, less invasive procedures have been developed that record eye movements with camera-based systems attached to a helmet worn by the subject. Computational algorithms have also been developed that can calibrate eye orientation when the head’s position is fixed. Given that camera-based systems measure the eye’s position in its orbit, however, the reconstruction of gaze orientation is not as straightforward when the head is allowed to move. In this paper, we propose a new algorithm and calibration method to compute gaze orientation under unrestrained head conditions. Our method requires only the accurate measurement of orbital eye position (for instance, with a camera-based system), and the position of three points on the head. The calculations are expressed in terms of linear algebra, so can easily be interpreted and related to the geometry of the human body. Our calibration method has been tested experimentally and validated against independent data, proving that is it robust even under large translations, rotations, and torsions of the head. © 2006 Elsevier B.V. All rights reserved

Reinforced ice structures:in the footsteps of Candela

Based on project experience over the last years, fibre reinforced ice has proven to be a strong and suitable building material for temporary structures in a cold environment. Unlike traditional igloo structures, no stacked blocks are used. Instead, relatively thin shells are created by spraying subsequent thin layers of water mixed with cellulose fibres on inflatable formwork which is removed afterwards. This paper describes the overall design process and construction of a full-scale cellulose-ice composite structure, inspired by Félix Candela’s famous reinforced concrete hypar shells. The project was built by university students and staff in the framework of an international project in Finland during the winter of early 2016.</p

Reinforced ice structures: In the footsteps of Candela

Based on project experience over the last years, fibre reinforced ice has proven to be a strong and suitable building material for temporary structures in a cold environment. Unlike traditional igloo structures, no stacked blocks are used. Instead, relatively thin shells are created by spraying subsequent thin layers of water mixed with cellulose fibres on inflatable formwork which is removed afterwards. This paper describes the overall design process and construction of a full-scale cellulose-ice composite structure, inspired by Félix Candela’s famous reinforced concrete hypar shells. The project was built by university students and staff in the framework of an international project in Finland during the winter of early 2016.Universiteit Gentinfo:eu-repo/semantics/publishedVersio

Ditto – Deterministic Execution Replayability-as-a-Service for Java VM on Multiprocessors

Part 4: ServicesInternational audienceAlongside the rise of multi-processor machines, concurrent programming models have grown to near ubiquity. Programs built on these models are prone to bugs with rare pre-conditions, arising from unanticipated interactions between parallel tasks. Replayers can be efficient on uni-processor machines, but struggle with unreasonable overhead on multi-processors, both concerning slowdown of the execution time and size of the replay log. We present Ditto, a deterministic replayer for concurrent JVM applications executed on multi-processor machines, using both state-of-the-art and novel techniques. The main contribution of Ditto is a novel pair of recording and replaying algorithms that: (a) serialize memory accesses at the instance field level, (b) employ partial transitive reduction and program-order pruning on-the-fly, (c) take advantage of TLO static analysis, escape analysis and JVM compiler optimizations to identify thread-local accesses, and (d) take advantage of a lightweight checkpoint mechanism to avoid large logs in long running applications with fine granularity interactions, and for faster replay to any point in execution. The results show that Ditto out-performs previous deterministic replayers targeted at Java programs