Automatic Detection of Performance Anomalies in Task-Parallel Programs

To efficiently exploit the resources of new many-core architectures, integrating dozens or even hundreds of cores per chip, parallel programming models have evolved to expose massive amounts of parallelism, often in the form of fine-grained tasks. Task-parallel languages, such as OpenStream, X10, Habanero Java and C or StarSs, simplify the development of applications for new architectures, but tuning task-parallel applications remains a major challenge. Performance bottlenecks can occur at any level of the implementation, from the algorithmic level (e.g., lack of parallelism or over-synchronization), to interactions with the operating and runtime systems (e.g., data placement on NUMA architectures), to inefficient use of the hardware (e.g., frequent cache misses or misaligned memory accesses); detecting such issues and determining the exact cause is a difficult task. In previous work, we developed Aftermath, an interactive tool for trace-based performance analysis and debugging of task-parallel programs and run-time systems. In contrast to other trace-based analysis tools, such as Paraver or Vampir, Aftermath offers native support for tasks, i.e., visualization, statistics and analysis tools adapted for performance debugging at task granularity. However, the tool currently does not provide support for the automatic detection of performance bottlenecks and it is up to the user to investigate the relevant aspects of program execution by focusing the inspection on specific slices of a trace file. In this paper, we present ongoing work on two extensions that guide the user through this process.Comment: Presented at 1st Workshop on Resource Awareness and Adaptivity in Multi-Core Computing (Racing 2014) (arXiv:1405.2281

A new curcuma extract (flexofytol(R)) in osteoarthritis: results from a belgian real-life experience.

This retrospective observational study summarizes the experiences of 820 patients treated with a new Curcuma extract (Flexofytol(R), 4-6 capsules per day), for more than 6 months for various forms of painful osteoarthritis. These experiences were reported by 110 Belgian general practitioners via a questionnaire that included quality-of-life parameters for assessing patient experience. Data were submitted to an independent statistician for analysis. Within the first 6 weeks, Flexofytol(R) improved patient pain, articular mobility, and quality of life. Excellent tolerance was reported, and more than half of these patients were able to discontinue analgaesic and anti-inflammatory drugs. Patient satisfaction was confirmed by their decision to maintain Flexofytol(R) therapy for more than 6 months. These data must be confirmed with randomized controlled studies. We currently conclude that Flexofytol(R) which is based on a new preparation of curcumin, is as a potential neutraceutical for the care of patients complaining of joint problems, with excellent tolerance and rapid benefits for articular mobility, pain, and quality of life.Peer reviewe

Mid-infrared frequency combs

Laser frequency combs are coherent light sources that emit a broad spectrum consisting of discrete, evenly spaced narrow lines, each having an absolute frequency measurable within the accuracy of an atomic clock. Their development, a decade ago, in the near-infrared and visible domains has revolutionized frequency metrology with numerous windfalls into other fields such as astronomy or attosecond science. Extension of frequency comb techniques to the mid-infrared spectral region is now under exploration. Versatile mid-infrared frequency comb generators, based on novel laser gain media, nonlinear frequency conversion or microresonators, promise to significantly expand the tree of applications of frequency combs. In particular, novel approaches to molecular spectroscopy in the fingerprint region, with dramatically improved precision, sensitivity, recording time and/or spectral bandwidth may spark off new discoveries in the various fields relevant to molecular sciences

Musicothérapie et intervention musicale auprès d’enfants atteints du trouble déficitaire de l’attention avec ou sans hyperactivité : une recension des écrits

Le trouble déficitaire de l’attention avec ou sans hyperactivité (TDAH) est le trouble le plus diagnostiqué chez les enfants et l’une des principales raisons pour lesquelles un enfant est référé en soins de santé mentale. Les musicothérapeutes et les intervenants en psychologie, en neurosciences, en éducation et en d’autres domaines ont développé des interventions et des méthodes d’évaluation qui utilisent la musique en tenant compte des caractéristiques complexes de ce trouble qui affecte les fonctions cognitives et psychologiques, la motricité et les comportements. Cette recension des écrits inclut 23 études parues en anglais et en français entre 1998 et 2018 : 11 articles de recherche publiés et révisés par les pairs, huit thèses de doctorat et quatre mémoires de maîtrise. Elle rassemble des connaissances au sujet de l’utilisation de la musique auprès des jeunes âgés de 4 à 18 ans, présentant un TDAH. Les études portent sur des interventions en musicothérapie, sur des interventions musicales non musicothérapeutiques, sur des tests de perception musicale ainsi que sur les effets de l’écoute musicale durant une tâche et durant la pratique musicale. Sur un total de 23 études, cinq études (22 %) témoignent des bénéfices d’une intervention spécifique à la musicothérapie auprès d’enfants ayant un TDAH tandis que 17 autres (74 %) démontrent des bénéfices par l’utilisation de la musique. Une étude n’a pas identifié de bénéfices. Les résultats démontrent que la recherche informe et guide les musicothérapeutes dans leur pratique auprès d’enfants ayant un TDAH, mais que plus de recherche est nécessaire pour bien saisir l’impact des interventions en musicothérapie

Accuracy of digital complete-arch, multi-implant scans made in the edentulous jaw with gingival movement simulation: An in vitro study

STATEMENT OF PROBLEM The use of computer-aided design and computer-aided manufacturing (CAD-CAM) technologies is widely established, with single restorations or short fixed partial dentures having similar accuracy when generated from digital scans or conventional impressions. However, research on complete-arch scanning of edentulous jaws is sparse. PURPOSE The purpose of this pilot in vitro study was to compare the accuracy of a digital scan with the conventional method in a workflow generating implant-supported complete-arch prostheses and to establish whether interference from flexible soft tissue segments affects accuracy. MATERIAL AND METHODS An edentulous maxillary master cast containing 6 angled implant analogs was used and digitized with mounted scan bodies by using a high-precision laboratory scanner. The master cast was then scanned 10 times with 4 different intraoral scanners: TRIOS 3 with a complete-arch scanning strategy (TRI1) or implant-scanning strategy (TRI2), TRIOS Color (TRC), CEREC Omnicam (CER), and CEREC Primescan (PS). The same procedure was repeated with 4 different levels of free gingiva (G0-G3). Ten conventional impressions were obtained. Differences in implant position and direction were evaluated at the implant shoulder as mean values for trueness and interquartile range (IQR) for precision. Statistical analysis was performed by using the Kruskal-Wallis and post hoc Conover tests (α=.05). RESULTS At G0, position deviations ranged from 34.8 μm (IQR 23.0 μm) (TRC) to 68.3 μm (12.2 μm) (CER). Direction deviations ranged from 0.34 degrees (IQR 0.18 degrees) (conventional) to 0.57 degrees (IQR 0.37 degrees) (TRI2). For digital systems, the position deviation ranged from 48.4 μm (IQR 5.9 μm) (PS) to 76.6 μm (IQR 8.1 μm) (TRC) at G1, from 36.3 μm (IQR 9.3 μm) (PS) to 79.9 μm (IQR 36.1 μm) (TRI1) at G2, and from 51.8 μm (IQR 14.3 μm) (PS) to 257.5 μm (IQR 106.3 μm) (TRC) at G3. The direction deviation ranged from 0.45 degrees (IQR 0.15 degrees) (CER) to 0.64 degrees (IQR 0.20 degrees) (TRC) at G1, from 0.38 degrees (IQR 0.05 degrees) (PS) to 0.925 degrees (IQR 0.09 degrees) (TRI) at G2, and from 0.44 degrees (IQR 0.07 degrees) (PS) to 1.634 degrees (IQR 1.08 degrees) (TRI) at G3. Statistical analysis revealed significant differences among the test groups for position (G0: P<.001; G1: P<.05; G2: P<.001; G3: P<.001) and direction (G0: P<.005; G1: P<.001; G2: P<.001; G3: P<.001). CONCLUSIONS Without soft tissue interference, the accuracy of certain digital scanning systems was comparable with that of the conventional impression technique. The amount of flexible soft tissue interference affected the accuracy of the digital scans

Scalable Task Parallelism for NUMA: A Uniform Abstraction for Coordinated Scheduling and Memory Management

International audienceDynamic task-parallel programming models are popular on shared-memory systems, promising enhanced scalability, load balancing and locality. Yet these promises are undermined by non-uniform memory access (NUMA). We show that using NUMA-aware task and data placement, it is possible to preserve the uniform abstraction of both computing and memory resources for task-parallel programming models while achieving high data locality. Our data placement scheme guarantees that all accesses to task output data target the local memory of the accessing core. The complementary task placement heuristic improves the locality of task input data on a best effort basis. Our algorithms take advantage of data-flow style task parallelism, where the privatization of task data enhances scalability by eliminating false dependences and enabling fine-grained dynamic control over data placement. The algorithms are fully automatic, application-independent, performance-portable across NUMA machines, and adapt to dynamic changes. Placement decisions use information about inter-task data dependences readily available in the run-time system and placement information from the operating system. We achieve 94% of local memory accesses on a 192-core system with 24 NUMA nodes, up to 5× higher performance than NUMA-aware hierarchical work-stealing, and even 5.6× compared to static interleaved allocation. Finally, we show that state-of-the-art dynamic page migration by the operating system cannot catch up with frequent affinity changes between cores and data and thus fails to accelerate task-parallel applications

Topology-Aware and Dependence-Aware Scheduling and Memory Allocation for Task-Parallel Languages

International audienceWe present a joint scheduling and memory allocation algorithm for efficient execution of task-parallel programs on non-uniform memory architecture (NUMA) systems. Task and data placement decisions are based on a static description of the memory hierarchy and on runtime information about intertask communication. Existing locality-aware scheduling strategies for fine-grained tasks have strong limitations: they are specific to some class of machines or applications, they do not handle task dependences, they require manual program annotations, or they rely on fragile profiling schemes. By contrast, our solution makes no assumption on the structure of programs or on the layout of data in memory. Experimental results, based on the OpenStream language, show that locality of accesses to main memory of scientific applications can be increased significantly on a 64-core machine, resulting in a speedup of up to 1.63× compared to a state-of-the-art work-stealing scheduler

Recurrence pattern analysis after re-irradiation with bevacizumab in recurrent malignant glioma patients

Background: The aim of the present analysis was to evaluate the recurrence pattern in patients with recurrent malignant glioma after re-irradiation in combination with bevacizumab as there is limited data on how to optimally choose dose, fractionation and delineation margins. Methods: Thirty-one patients with recurrent malignant glioma treated with re-irradiation and bevacizumab after previous chemoradiotherapy (concurrent temozolomide 75 mg/m(2)/d according to the EORTC/NCIC trial) and [F-18]FET-PET and/or MRI confirmed recurrence were retrospectively analyzed. Bevacizumab was applied twice during fractionated re-irradiation (10 mg/kg, d1 + d15, median 36 Gy, conventionally fractionated). Recurrence patterns were assessed by means of [F-18]FET-PET and/or MRI. Results: Median follow-up was 34.0 months for all patients [95%-CI, 27.7-40.3] and median post-recurrence survival 10.8 months [95%-CI, 9.2-12.4]. Concerning the recurrence patterns, 61.3% of these were located in-field (19 patients), 22.6% were marginal (7 patients) and 16.1% ex-field (5 patients). No influence on the recurrence pattern was observed according to sex, WHO grade, maintenance chemotherapy or MGMT methylation status whereas planning target volume (PTV) size had a significant influence on the recurrence pattern (p = 0.032). PTV sizes >75 ml were associated with a higher in-field recurrence rate and lower median post-recurrence progression-free survival (8.5 vs. 4.9 months, p = 0.016). Conclusions: After the administration of re-irradiation with bevacizumab the recurrence pattern seems to be mainly centrally located. The PTV size was the main predictor for a marginal/ex-field recurrence