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result(s) for
"Klein, Jacques"
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Digital Biologically Plausible Implementation of Binarized Neural Networks With Differential Hafnium Oxide Resistive Memory Arrays
by
Klein, Jacques-Olivier
,
Bocquet, Marc
,
Querlioz, Damien
in
Artificial intelligence
,
ASICs
,
binarized neural networks
2020
The brain performs intelligent tasks with extremely low energy consumption. This work takes its inspiration from two strategies used by the brain to achieve this energy efficiency: the absence of separation between computing and memory functions and reliance on low-precision computation. The emergence of resistive memory technologies indeed provides an opportunity to tightly co-integrate logic and memory in hardware. In parallel, the recently proposed concept of a Binarized Neural Network, where multiplications are replaced by exclusive NOR (XNOR) logic gates, offers a way to implement artificial intelligence using very low precision computation. In this work, we therefore propose a strategy for implementing low-energy Binarized Neural Networks that employs brain-inspired concepts while retaining the energy benefits of digital electronics. We design, fabricate, and test a memory array, including periphery and sensing circuits, that is optimized for this in-memory computing scheme. Our circuit employs hafnium oxide resistive memory integrated in the back end of line of a 130-nm CMOS process, in a two-transistor, two-resistor cell, which allows the exclusive NOR operations of the neural network to be performed directly within the sense amplifiers. We show, based on extensive electrical measurements, that our design allows a reduction in the number of bit errors on the synaptic weights without the use of formal error-correcting codes. We design a whole system using this memory array. We show on standard machine learning tasks (MNIST, CIFAR-10, ImageNet, and an ECG task) that the system has inherent resilience to bit errors. We evidence that its energy consumption is attractive compared to more standard approaches and that it can use memory devices in regimes where they exhibit particularly low programming energy and high endurance. We conclude the work by discussing how it associates biologically plausible ideas with more traditional digital electronics concepts.
Journal Article
Differentiating kidney stones from phleboliths in unenhanced low-dose computed tomography using radiomics and machine learning
by
Hofmeister, Jeremy
,
Martin, Steve P
,
Klein, Jacques
in
Accuracy
,
Algorithms
,
Artificial intelligence
2019
ObjectivesDistinguishing between kidney stones and phleboliths can constitute a diagnostic challenge in patients undergoing unenhanced low-dose CT (LDCT) for acute flank pain. We sought to investigate the accuracy of radiomics and a machine-learning classifier in differentiating between kidney stones and phleboliths on LDCT.MethodsRadiomics features were extracted following a semi-automatic segmentation of kidney stones and phleboliths for two independent consecutive cohorts of patients undergoing LDCT for acute flank pain.Radiomics features from the first cohort of patients (n = 369) were ultimately used to train a machine-learning model designed to distinguish kidney stones (n = 211) from phleboliths (n = 201). Classification performance was assessed on the second independent cohort (i.e., testing set) (kidney stones n = 24; phleboliths n = 23) using positive and negative predictive values (PPV and NPV), area under the receiver operating curves (AUC), and permutation testing.ResultsOur machine-learning classification model trained on radiomics features achieved an overall accuracy of 85.1% on the independent testing set, with an AUC of 0.902, PPV of 81.5%, and NPV of 90.0%. Classification accuracy was significantly better than chance on permutation testing (p < 0.05, permutation p value).ConclusionRadiomics and machine learning enable accurate differentiation between kidney stones and phleboliths on LDCT in patients presenting with acute flank pain.Key Points• Combining a machine-learning algorithm with radiomics features extracted for abdominopelvic calcification on LDCT offers a highly accurate method for discriminating phleboliths from kidney stones.• Our radiomics and machine-learning model proved robust for CT acquisition and reconstruction protocol when tested in comparison with an external independent cohort of patients with acute flank pain.• The high performance of the radiomics-based automatic classification model in differentiating phleboliths from kidney stones indicates its potential as a future diagnostic tool for equivocal abdominopelvic calcifications in the setting of suspected renal colic.
Journal Article
Current-limiting challenges for all-spin logic devices
by
Klein, Jacques-Olivier
,
Zhang, Youguang
,
Su, Li
in
639/301/1005/1007
,
639/766/25
,
639/925/918/1052
2015
All-spin logic device (ASLD) has attracted increasing interests as one of the most promising post-CMOS device candidates, thanks to its low power, non-volatility and logic-in-memory structure. Here we investigate the key current-limiting factors and develop a physics-based model of ASLD through nano-magnet switching, the spin transport properties and the breakdown characteristic of channel. First, ASLD with perpendicular magnetic anisotropy (PMA) nano-magnet is proposed to reduce the critical current (
I
c0
). Most important, the spin transport efficiency can be enhanced by analyzing the device structure, dimension, contact resistance as well as material parameters. Furthermore, breakdown current density (
J
BR
) of spin channel is studied for the upper current limitation. As a result, we can deduce current-limiting conditions and estimate energy dissipation. Based on the model, we demonstrate ASLD with different structures and channel materials (graphene and copper). Asymmetric structure is found to be the optimal option for current limitations. Copper channel outperforms graphene in term of energy but seriously suffers from breakdown current limit. By exploring the current limit and performance tradeoffs, the optimization of ASLD is also discussed. This benchmarking model of ASLD opens up new prospects for design and implementation of future spintronics applications.
Journal Article
Physical Realization of a Supervised Learning System Built with Organic Memristive Synapses
by
Chabi, Djaafar
,
Klein, Jacques-Olivier
,
Querlioz, Damien
in
142/126
,
639/925/927/1007
,
639/925/929/115
2016
Multiple modern applications of electronics call for inexpensive chips that can perform complex operations on natural data with limited energy. A vision for accomplishing this is implementing hardware neural networks, which fuse computation and memory, with low cost organic electronics. A challenge, however, is the implementation of synapses (analog memories) composed of such materials. In this work, we introduce robust, fastly programmable, nonvolatile organic memristive nanodevices based on electrografted redox complexes that implement synapses thanks to a wide range of accessible intermediate conductivity states. We demonstrate experimentally an elementary neural network, capable of learning functions, which combines four pairs of organic memristors as synapses and conventional electronics as neurons. Our architecture is highly resilient to issues caused by imperfect devices. It tolerates inter-device variability and an adaptable learning rule offers immunity against asymmetries in device switching. Highly compliant with conventional fabrication processes, the system can be extended to larger computing systems capable of complex cognitive tasks, as demonstrated in complementary simulations.
Journal Article
A compact model for magnetic tunnel junction (MTJ) switched by thermally assisted Spin transfer torque (TAS + STT)
by
Chappert, Claude
,
Zhao, Weisheng
,
Klein, Jacques-Olivier
in
11th Trends in NanoTechnology International Conference (TNT2010)
,
Chemistry and Materials Science
,
Materials Science
2011
Thermally assisted spin transfer torque [TAS + STT] is a new switching approach for magnetic tunnel junction [MTJ] nanopillars that represents the best trade-off between data reliability, power efficiency and density. In this paper, we present a compact model for MTJ switched by this approach, which integrates a number of physical models such as temperature evaluation and STT dynamic switching models. Many experimental parameters are included directly to improve the simulation accuracy. It is programmed in the Verilog-A language and compatible with the standard IC CAD tools, providing an easy parameter configuration interface and allowing high-speed co-simulation of hybrid MTJ/CMOS circuits.
Journal Article
On Locating Malicious Code in Piggybacked Android Apps
by
Li Li;Daoyuan Li;Tegawende F. Bissyande;Jacques Klein;Haipeng Cai;David Lo;Yves Le Traon
in
Applications programs
,
Artificial Intelligence
,
Building codes
2017
To devise efficient approaches and tools for detecting malicious packages in the Android ecosystem, researchers are increasingly required to have a deep understanding of malware. There is thus a need to provide a framework for dissecting malware and locating malicious program fragments within app code in order to build a comprehensive dataset of malicious samples. Towards addressing this need, we propose in this work a tool-based approach called HookRanker, which provides ranked lists of potentially malicious packages based on the way malware behaviour code is triggered. With experiments on a ground truth of piggybacked apps, we are able to automatically locate the malicious packages from piggybacked Android apps with an accuracy@5 of 83.6% for such packages that are triggered through method invocations and an accuracy@5 of 82.2% for such packages that are triggered independently.
Journal Article
On Identifying and Explaining Similarities in Android Apps
2019
App updates and repackaging are recurrent in the Android ecosystem, filling markets with similar apps that must be identified. Despite the existence of several approaches to improving the scalability of detecting repackaged/cloned apps, researchers and practitioners are eventually faced with the need for a comprehensive pairwise comparison (or simultaneously multiple app comparisons) to understand and validate the similarities among apps. In this work, we present the design and implementation of our research-based prototype tool called SimiDroid for multi-level similarity comparison of Android apps. SimiDroid is built with the aim to support the comprehension of similarities/changes among app versions and among repackaged apps. In particular, we demonstrate the need and usefulness of such a framework based on different case studies implementing different dissection scenarios for revealing various insights on how repackaged apps are built. We further show that the similarity comparison plugins implemented in SimiDroid yield more accurate results than the state of the art.
Journal Article
FixMiner: Mining relevant fix patterns for automated program repair
2020
Patching is a common activity in software development. It is generally performed on a source code base to address bugs or add new functionalities. In this context, given the recurrence of bugs across projects, the associated similar patches can be leveraged to extract generic fix actions. While the literature includes various approaches leveraging similarity among patches to guide program repair, these approaches often do not yield fix patterns that are tractable and reusable as actionable input to APR systems. In this paper, we propose a systematic and automated approach to mining relevant and actionable fix patterns based on an iterative clustering strategy applied to atomic changes within patches. The goal of FixMiner is thus to infer separate and reusable fix patterns that can be leveraged in other patch generation systems. Our technique, FixMiner, leverages Rich Edit Script which is a specialized tree structure of the edit scripts that captures the AST-level context of the code changes. FixMiner uses different tree representations of Rich Edit Scripts for each round of clustering to identify similar changes. These are abstract syntax trees, edit actions trees, and code context trees. We have evaluated FixMiner on thousands of software patches collected from open source projects. Preliminary results show that we are able to mine accurate patterns, efficiently exploiting change information in Rich Edit Scripts. We further integrated the mined patterns to an automated program repair prototype, PARFixMiner, with which we are able to correctly fix 26 bugs of the Defects4J benchmark. Beyond this quantitative performance, we show that the mined fix patterns are sufficiently relevant to produce patches with a high probability of correctness: 81% of PARFixMiner’s generated plausible patches are correct.
Journal Article
Le Royaume juif de Rouen ressuscité
2018
Histoire du plus ancien édifice hébraïque de France, La Maison Sublime, rénovée en 2018. En 1976, des travaux de pavage dans la cour du Palais de Justice de Rouen mettent à jour les vestiges de deux monuments hébraïques des XIe-XIIe siècles. L'un, aujourd'hui connu comme « la Maison Sublime », aurait abrité une académie rabbinique, l'autre un bain rituel. Deux autres monuments sont découverts dans les années 80, dont l'hôtel particulier du chef de la communauté juive. Ces vestiges, auxquels il faut ajouter une synagogue médiévale détruite à la fin du XIXe siècle, font de Rouen l'un des hauts-lieux de l'archéologie juive en Europe.Ces découvertes sont venues confirmer l'existence d'une communauté médiévale puissante et influente, arrivée en Normandie avec le colonisateur romain et qui a vécu là, mais aussi en Angleterre, jusqu'à l'expulsion des Juifs de France par Philippe le Bel. A partir du XVIe siècle, une communauté se reforme, constituée de « nouveaux chrétiens » chassés d'Espagne et du Portugal, puis de rapatriés d'Alsace-Lorraine et du Maghreb, de persécutés fuyant les dictatures communistes et fascistes. Cette communauté a connu, durant la dernière guerre, le plus terrible des holocaustes. Jacques-Sylvain Klein nous raconte l'histoire foisonnante du judaïsme normand sur près de deux mille ans. Il nous éclaire sur le rôle considérable du « royaume juif de Rouen » au Moyen Âge, sur ses relations avec la chrétienté et avec les grands foyers du judaïsme européen et oriental. Il nous fait découvrir l'exceptionnel rayonnement de l'École de Rouen, dont les maîtres ont nourri les premières éditions imprimées du Talmud. L'auteur nous conte aussi la rude bataille menée, pendant dix ans, par l'association La Maison Sublime de Rouen, dont il est le délégué, pour sauvegarder ce monument historique, le plus ancien édifice hébraïque conservé en France. Une bataille qui se termine, en 2018, avec la restauration de l'édifice et sa réouverture au public. Partez sur les traces historiques du judaïsme français et découvrez le récit d'une découverte fondamentale pour l'histoire du judaïsme en France. EXTRAIT Rouen n'a jamais été identifiée par les historiens comme un foyer de culture juive. Longtemps, la ville est même restée, pour les études juives médiévales, une terra quasi incognita. C'est tout juste si les deux ouvrages de référence, publiés en 1897 par Henri Gross et en 1972 par Bernhard Blumenkranz y consacrent quelques lignes.
Si Rouen est restée si longtemps absente de l'histoire du judaïsme français, cela tient d'abord à l'expulsion des Juifs de France décidée par Philippe le Bel en 1306. Alors que, dans le reste du pays, cette décision fait généralement l'objet d'une application nuancée – selon la vieille pratique des exemptions moyennant finances – puis se trouve partiellement rapportée par ses successeurs, elle s'applique à Rouen d'une manière brutale: la totalité des propriétés possédées par les Juifs, dans la ville et la banlieue, sont, dès l'année suivante, cédées à la municipalité et leurs habitations aussitôt occupées par des résidents chrétiens. À PROPOS DE L'AUTEUR Jacques-Sylvain Klein est l'auteur d'une douzaine d'ouvrages. Il a publié en 2006 La Maison Sublime, l'École rabbinique et le royaume juif de Rouen, qualifié par le Nouvel Obs de « Sublime bouquin ». Il a créé en 2010 le Festival Normandie Impressionniste et remporté en 2016 le prix Lévarey-Lévêque pour L'impressionnisme se lève en Normandie 1820-1886. Il est directeur honoraire de l'Assemblée nationale et ancien adjoint au maire de Rouen.
Lessons Learnt on Reproducibility in Machine Learning Based Android Malware Detection
by
Allix, Kevin
,
Bissyandé, Tegawendé F
,
Klein, Jacques
in
Cybersecurity
,
Evaluation
,
Machine learning
2021
A well-known curse of computer security research is that it often produces systems that, while technically sound, fail operationally. To overcome this curse, the community generally seeks to assess proposed systems under a variety of settings in order to make explicit every potential bias. In this respect, recently, research achievements on machine learning based malware detection are being considered for thorough evaluation by the community. Such an effort of comprehensive evaluation supposes first and foremost the possibility to perform an independent reproduction study in order to sharpen evaluations presented by approaches’ authors. The question Can published approaches actually be reproduced? thus becomes paramount despite the little interest such mundane and practical aspects seem to attract in the malware detection field. In this paper, we attempt a complete reproduction of five Android Malware Detectors from the literature and discuss to what extent they are “reproducible”. Notably, we provide insights on the implications around the guesswork that may be required to finalise a working implementation. Finally, we discuss how barriers to reproduction could be lifted, and how the malware detection field would benefit from stronger reproducibility standards—like many various fields already have.
Journal Article