Exceptions for Algorithmic Skeletons

to appearInternational audienceAlgorithmic Skeletons offer high-level abstractions for parallel programming based on recurrent parallelism patterns. Patterns can be combined and nested into more complex parallelism behaviors. Programmers fill the skeleton patterns with the functional (business) code, which transforms the generic skeleton into a specific application. However, when the functional code generate exceptions, this exposes the programmer to details of the skeleton library, breaking the high-level abstraction principle. Furthermore, related parallel activities must be stopped as the exception is raised. This paper describes how to handle exceptions in Algorithmic Skeletons without breaking the high-level abstractions of the programming model. We describe both the behavior of the framework in a formal way, and its implementation in Java: the Skandium Library

Recurrent Ischemic Stroke and Bleeding in Patients With Atrial Fibrillation Who Suffered an Acute Stroke While on Treatment With Nonvitamin K Antagonist Oral Anticoagulants: The RENO-EXTEND Study

Background: In patients with atrial fibrillation who suffered an ischemic stroke while on treatment with nonvitamin K antagonist oral anticoagulants, rates and determinants of recurrent ischemic events and major bleedings remain uncertain. Methods: This prospective multicenter observational study aimed to estimate the rates of ischemic and bleeding events and their determinants in the follow-up of consecutive patients with atrial fibrillation who suffered an acute cerebrovascular ischemic event while on nonvitamin K antagonist oral anticoagulant treatment. Afterwards, we compared the estimated risks of ischemic and bleeding events between the patients in whom anticoagulant therapy was changed to those who continued the original treatment. Results: After a mean follow-up time of 15.0±10.9 months, 192 out of 1240 patients (15.5%) had 207 ischemic or bleeding events corresponding to an annual rate of 13.4%. Among the events, 111 were ischemic strokes, 15 systemic embolisms, 24 intracranial bleedings, and 57 major extracranial bleedings. Predictive factors of recurrent ischemic events (strokes and systemic embolisms) included CHA2DS2-VASc score after the index event (odds ratio [OR], 1.2 [95% CI, 1.0–1.3] for each point increase; P=0.05) and hypertension (OR, 2.3 [95% CI, 1.0–5.1]; P=0.04). Predictive factors of bleeding events (intracranial and major extracranial bleedings) included age (OR, 1.1 [95% CI, 1.0–1.2] for each year increase; P=0.002), history of major bleeding (OR, 6.9 [95% CI, 3.4–14.2]; P=0.0001) and the concomitant administration of an antiplatelet agent (OR, 2.8 [95% CI, 1.4–5.5]; P=0.003). Rates of ischemic and bleeding events were no different in patients who changed or not changed the original nonvitamin K antagonist oral anticoagulants treatment (OR, 1.2 [95% CI, 0.8–1.7]). Conclusions: Patients suffering a stroke despite being on nonvitamin K antagonist oral anticoagulant therapy are at high risk of recurrent ischemic stroke and bleeding. In these patients, further research is needed to improve secondary prevention by investigating the mechanisms of recurrent ischemic stroke and bleeding

High Level Tranforms to reduce energy consumption of signal and image processing operators

International audienceHigh Level Synthesis for Systems on Chip is a challenging way to cut off development time, while assuming a good level of performance. But the HLS tools are limited by the abstraction level of the description to perform some high level transforms.This paper evaluates the impact of such high level transforms for ASICs. We have evaluated recursive and non recursive filters for signal processing an morphological filters for image processing. We show that the impact of HLTs to reduce energy consumption is high : from ×3.4 for one 1D filter up to ×5.6 for cascaded 1D filters and about ×3.5 for morphological 2D filters

Impact of High Level Transforms on High Level Synthesis for motion detection algorithm

International audienceHigh Level Synthesis for System on Chip is a challenging way to cut off development time, while assuming a good level of performance. But the HLS tools are limited by the abstraction level of the description to perform some high level transforms. This paper evaluates the impact of such high level transforms for ASICs and softcores on FPGA. On the representative example of motion detection, we show that we have a speedup of ×1.5 for a softcore on FPGA and ×2.5 for an ASIC while the energy is divided by a factor ×2.90 for the ASIC

A distributed approach to 3D reconstruction in marker motion capture systems

Optical motion capture systems have attracted much interest over the past years, due to their advantages with respect to non-optical counterparts. Moreover, with the technological advances on camera devices, computer graphics and computational methodologies, it becomes technically and economically feasible to consider motion capture systems made of large networks of cameras with embedded communication and processing units on board (i.e., smart cameras). In this case, the approaches relying on the classical 3D reconstruction methods would become inefficient, since their nature is intrinsically centralized. For this reason, we propose a distributed 3D reconstruction algorithm, which relies on a specific organization of cameras to remarkably speed up the scene reconstruction task. Indeed, numerical and experimental results show that the proposed computational scheme overcomes classical centralized solutions, in terms of reconstruction speed. Furthermore, the high processing speed does not compromise the estimation accuracy, since the algorithm is designed to be robust to occlusions and noise

Stratégie préventive originale des infections urinaires symptomatiques chez les patients porteurs d’une vessie neurologique : l’interférence bactérienne, état de l’art

International audiencePURPOSE:Urinary tract infection (UTI) is the most common complication in patients with neurogenic bladder. The long-term use of antibiotic drugs induces an increase in antimicrobial resistance and adverse drug reactions. Bacterial interference is a new concept to prevent recurrent UTI which consists in a bladder colonization with low virulence bacteria. We performed a literature review on this emerging therapy.MATERIALS AND METHODS:Literature review of bacterial interference to prevent symptomatic urinary tract infection in neurological population.RESULTS:Seven prospectives study including 3 randomized, double-blind and placebo controlled trial were analyzed. The neurological population was spinal cord injured in most cases. The bladder colonization was performed with 2 non-pathogen strains of Escherichia coli: HU 2117 and 83972. At 1 month, 38 to 83% of patients were colonized. Mean duration of colonization was 48.5 days to 12.3 months. All studies showed that colonization might reduce the number of urinary tract infections and is safe with absence of serious side effects.CONCLUSION:Bacterial interference is a promising alternative therapy for the prevention of recurrent symptomatic urinary tract infections in neurogenic patients. This therapy should have developments for a daily use practice and for a long-term efficacy