Animaciones interactivas para la enseñanza y aprendizaje de los protocolos de coherencia de cachés

Entre los objetivos formativos de los cursos avanzados de arquitectura de computadores suele estar el de que los estudiantes sean capaces de describir y analizar el funcionamiento de los protocolos de coherencia de cachés. Aunque dichos protocolos son relativamente sencillos, es necesario analizar muchas situaciones diferentes para entender cómo abordan todos los detalles del problema que quieren resolver. Lo que hace que sean complejos de explicar y de comprender. Una herramienta que ilustrara gráficamente el funcionamiento de dichos protocolos facilitaría enormemente su enseñanza/aprendizaje. Con objeto de mejorar la docencia de dicha materia, hemos desarrollado tres animaciones interactivas que muestran cómo funcionan tres de los protocolos de coherencia de caché más frecuentemente utilizados. Para cada protocolo, una serie de operaciones de lectura/escritura ilustran todas las posibles situaciones que pueden darse. Las animaciones permiten avanzar y retroceder para poder entender/estudiar mejor las acciones que tienen lugar en cada paso.SUMMARY: Among the educational objectives in advanced courses of computers architecture there is usually one that states that students should be able to describe and analyze how the cache coherence protocols work. Although these protocols are relatively simple, it is necessary to analyze many different situations to understand how they address all the details of the problem they solve. This makes them complex to be explained and to be understood. A tool that illustrates graphically the operation of these protocols should greatly facilitate the teaching/learning of these protocols. With the aim of improving the teaching on this subject, we have developed three interactive animations that show how some of the most frequently used cache coherence protocols work. For each protocol, a sequence of read and write operations illustrates all possible situations that can take place in each protocol. The tool is interactive in that the student can go forward and backward to understand/ study the different actions that occur at each step.Peer Reviewe

Online learning via dynamic reranking for Computer Assisted Translation

New techniques for online adaptation in computer assisted translation are explored and compared to previously existing approaches. Under the online adaptation paradigm, the translation system needs to adapt itself to real-world changing scenarios, where training and tuning may only take place once, when the system is set-up for the first time. For this purpose, post-edit information, as described by a given quality measure, is used as valuable feedback within a dynamic reranking algorithm. Two possible approaches are presented and evaluated. The first one relies on the well-known perceptron algorithm, whereas the second one is a novel approach using the Ridge regression in order to compute the optimum scaling factors within a state-of-the-art SMT system. Experimental results show that such algorithms are able to improve translation quality by learning from the errors produced by the system on a sentence-by-sentence basis.This paper is based upon work supported by the EC (FEDER/FSE) and the Spanish MICINN under projects MIPRCV “Consolider Ingenio 2010” (CSD2007-00018) and iTrans2 (TIN2009-14511). Also supported by the Spanish MITyC under the erudito.com (TSI-020110-2009-439) project, by the Generalitat Valenciana under grant Prometeo/2009/014 and scholarship GV/2010/067 and by the UPV under grant 20091027Martínez Gómez, P.; Sanchis Trilles, G.; Casacuberta Nolla, F. (2011). Online learning via dynamic reranking for Computer Assisted Translation. En Computational Linguistics and Intelligent Text Processing. Springer Verlag (Germany). 6609:93-105. https://doi.org/10.1007/978-3-642-19437-5_8S931056609Brown, P., Pietra, S.D., Pietra, V.D., Mercer, R.: The mathematics of machine translation. In: Computational Linguistics, vol. 19, pp. 263–311 (1993)Zens, R., Och, F.J., Ney, H.: Phrase-based statistical machine translation. In: Jarke, M., Koehler, J., Lakemeyer, G. (eds.) KI 2002. LNCS (LNAI), vol. 2479, pp. 18–32. Springer, Heidelberg (2002)Koehn, P., Och, F.J., Marcu, D.: Statistical phrase-based translation. In: Proc. HLT/NAACL 2003, pp. 48–54 (2003)Callison-Burch, C., Fordyce, C., Koehn, P., Monz, C., Schroeder, J.: (meta-) evaluation of machine translation. In: Proc. of the Workshop on SMT. ACL, pp. 136–158 (2007)Papineni, K., Roukos, S., Ward, T.: Maximum likelihood and discriminative training of direct translation models. In: Proc. of ICASSP 1988, pp. 189–192 (1998)Och, F., Ney, H.: Discriminative training and maximum entropy models for statistical machine translation. In: Proc. of the ACL 2002, pp. 295–302 (2002)Och, F., Zens, R., Ney, H.: Efficient search for interactive statistical machine translation. In: Proc. of EACL 2003, pp. 387–393 (2003)Sanchis-Trilles, G., Casacuberta, F.: Log-linear weight optimisation via bayesian adaptation in statistical machine translation. In: Proceedings of COLING 2010, Beijing, China (2010)Callison-Burch, C., Bannard, C., Schroeder, J.: Improving statistical translation through editing. In: Proc. of 9th EAMT Workshop Broadening Horizons of Machine Translation and its Applications, Malta (2004)Barrachina, S., et al.: Statistical approaches to computer-assisted translation. Computational Linguistics 35, 3–28 (2009)Casacuberta, F., et al.: Human interaction for high quality machine translation. Communications of the ACM 52, 135–138 (2009)Ortiz-Martínez, D., García-Varea, I., Casacuberta, F.: Online learning for interactive statistical machine translation. In: Proceedings of NAACL HLT, Los Angeles (2010)España-Bonet, C., Màrquez, L.: Robust estimation of feature weights in statistical machine translation. In: 14th Annual Conference of the EAMT (2010)Reverberi, G., Szedmak, S., Cesa-Bianchi, N., et al.: Deliverable of package 4: Online learning algorithms for computer-assisted translation (2008)Crammer, K., Dekel, O., Keshet, J., Shalev-Shwartz, S., Singer, Y.: Online passive-aggressive algorithms. Journal of Machine Learning Research 7, 551–585 (2006)Snover, M., Dorr, B., Schwartz, R., Micciulla, L., Makhoul, J.: A study of translation edit rate with targeted human annotation. In: Proc. of AMTA, Cambridge, MA, USA (2006)Papineni, K., Roukos, S., Ward, T., Zhu, W.: Bleu: A method for automatic evaluation of machine translation. In: Proc. of ACL 2002 (2002)Rosenblatt, F.: The perceptron: A probabilistic model for information storage and organization in the brain. Psychological Review 65, 386–408 (1958)Collins, M.: Discriminative training methods for hidden markov models: Theory and experiments with perceptron algorithms. In: EMNLP 2002, Philadelphia, PA, USA, pp. 1–8 (2002)Koehn, P.: Europarl: A parallel corpus for statistical machine translation. In: Proc. of the MT Summit X, pp. 79–86 (2005)Koehn, P., et al.: Moses: Open source toolkit for statistical machine translation. In: Proc. of the ACL Demo and Poster Sessions, Prague, Czech Republic, pp. 177–180 (2007)Och, F.: Minimum error rate training for statistical machine translation. In: Proc. of ACL 2003, pp. 160–167 (2003)Kneser, R., Ney, H.: Improved backing-off for m-gram language modeling. In: IEEE Int. Conf. on Acoustics, Speech and Signal Processing II, pp. 181–184 (1995)Stolcke, A.: SRILM – an extensible language modeling toolkit. In: Proc. of ICSLP 2002, pp. 901–904 (2002

A probabilistic fatigue crack growth life approach to the definition of inspection intervals for railway axles

Different options that rely on fracture mechanics are currently used in engineering during the design and assessment of components. One of the most important aspects is the time taken for a crack to extend to its critical size. If this time is long enough, a design concept based on inspection intervals can be applied, as is it the case of a railway axle component. To define inspection intervals that ensure the continuous and safe operation of a damage-tolerant railway axle, a reliable estimation of its fatigue crack growth life is required. Due to the uncertainties involved in the fatigue process, inspections must be devised not only considering the uncertainties in the performance of the inspection technique, but also based on a probabilistic lifespan prediction. From this premise, this paper presents a procedure for determination of inspection intervals that uses a conservative fatigue crack growth life estimation based on the lifespan probability distribution. A practical example to illustrate the reliability-based inspection planning methodology in a railway axle under random bending loading is given. The inspection intervals are further assessed in terms of overall probability of detecting cracks in successive inspections and in terms of probability of failure, considering the probability of detection curve of the non-destructive testing technique. The procedure developed provides recommendation for the definition of inspection intervals and associated inspection techniques

Uncertainty propagation using the full second-order approach for probabilistic fatigue crack growth life

Uncertainty propagation of fatigue crack growth life commonly aims to provide the probability distribution of the lifespan needed for probabilistic damage tolerance analysis and for structural integrity assessment. This paper presents a novel methodology for efficiently estimating the parameters of the probability distribution of fatigue lifespan considering the Pearson distribution family. First, the full second-order approach for expected value and variance prediction of probabilistic fatigue crack growth life is extended to predict higher order statistical moments of the underlying distribution. That is, the expected value (first raw moment) and the variance (second central moment) equations are complemented with the probabilistic formulations for the skewness and for the kurtosis (third and fourth central standardized moments, respectively). Then, from these moments, the Pearson distribution type is automatically determined. Finally, the parameters of the particular Pearson distribution type are estimated making the statistical moments of the constructed lifespan distribution match the first four prescribed moments predicted by the probabilistic equations. The validity of the proposed method is verified by a numerical example regarding the fatigue crack growth in a railway axle under random bending loading. It is proven that the probability density function of the lifespan is properly derived by the methodology, without knowing or assuming the output probability distribution beforehand. The methodology presented enables an efficient and an accurate quantification of the lifespan uncertainties via its probabilistic distribution. This probabilistic description of fatigue crack growth life can be subsequently used in reliability studies or in damage tolerance assessment

Evaluation and tuning of the Level 3 CUBLAS for graphics processors

The increase in performance of the last generations of graphics processors (GPUs) has made this class of plat-form a coprocessing tool with remarkable success in certain types of operations. In this paper we evaluate the perfor-mance of the Level 3 operations in CUBLAS, the implemen-tation of BLAS for NVIDIA R © GPUs with unified architec-ture. From this study, we gain insights on the quality of the kernels in the library and we propose several alternative im-plementations that are competitive with those in CUBLAS. Experimental results on a GeForce 8800 Ultra compare the performance of CUBLAS and the new variants

Assessment of the effect of a new technique for laparoscopic partial closure of the inguinal canal on sperm production and testicular perfusion in stallions

In order to simplify other laparoscopic techniques, a new standing laparoscopic technique for partial closure of inguinal canal (PCIC) has been developed. This technique uses a new anchoring device and can be performed without advanced laparoscopic skills. The aim of this study was to develop a prior evaluation of the effects of this new technique on the stallion reproductive capacity, assessing the sperm production and testicular perfusion. Standing laparoscopic PCIC was performed unilaterally in 8 experimental stallions without evidence of inguinal hernia, using the contralateral canal and testicle as control

Concurrent and Accurate RNA Sequencing on Multicore Platforms

In this paper we introduce a novel parallel pipeline for fast and accurate mapping of RNA sequences on servers equipped with multicore processors. Our software, named HPG-Aligner, leverages the speed of the Burrows-Wheeler Transform to map a large number of RNA fragments (reads) rapidly, as well as the accuracy of the Smith-Waterman algorithm, that is employed to deal with conflictive reads. The aligner is complemented with a careful strategy to detect splice junctions based on the division of RNA reads into short segments (or seeds), which are then mapped onto a number of candidate alignment locations, providing useful information for the successful alignment of the complete reads. Experimental results on platforms with AMD and Intel multicore processors report the remarkable parallel performance of HPG-Aligner, on short and long RNA reads, which excels in both execution time and sensitivity to an state-of-the-art aligner such as TopHat 2 built on top of Bowtie and Bowtie 2

Concurrent and Accurate Short Read Mapping on Multicore Processors

We introduce a parallel aligner with a work-flow organization for fast and accurate mapping of RNA sequences on servers equipped with multicore processors. Our software, HPG Aligner SA1, exploits a suffix array to rapidly map a large fraction of the RNA fragments (reads), as well as leverages the accuracy of the Smith-Waterman algorithm to deal with conflictive reads. The aligner is enhanced with a careful strategy to detect splice junctions based on an adaptive division of RNA reads into small segments (or seeds), which are then mapped onto a number of candidate alignment locations, providing crucial information for the successful alignment of the complete reads. The experimental results on a platform with Intel multicore technology report the parallel performance of HPG Aligner SA, on RNA reads of 100–400 nucleotides, which excels in execution time/sensitivity to state-of-the-art aligners such as TopHat 2+Bowtie 2, MapSplice, and STAR.This work has been supported by the Bull-CIPF Chair for Computational Genomics. The researchers from the Jaume I University were supported by project TIN2011-23283 and FEDER

Animaciones interactivas para la enseñanza y aprendizaje de los protocolos de coherencia de cachés

Entre los objetivos formativos de los cursos avanzados de arquitectura de computadores suele estar el de que los estudiantes sean capaces de describir y analizar el funcionamiento de los protocolos de coherencia de cachés. Aunque dichos protocolos son relativamente sencillos, es necesario analizar muchas situaciones diferentes para entender cómo abordan todos los detalles del problema que quieren resolver. Lo que hace que sean complejos de explicar y de comprender. Una herramienta que ilustrara gráficamente el funcionamiento de dichos protocolos facilitaría enormemente su enseñanza/aprendizaje. Con objeto de mejorar la docencia de dicha materia, hemos desarrollado tres animaciones interactivas que muestran cómo funcionan tres de los protocolos de coherencia de caché más frecuentemente utilizados. Para cada protocolo, una serie de operaciones de lectura/escritura ilustran todas las posibles situaciones que pueden darse. Las animaciones permiten avanzar y retroceder para poder entender/estudiar mejor las acciones que tienen lugar en cada paso.Among the educational objectives in advanced courses of computers architecture there is usually one that states that students should be able to describe and analyze how the cache coherence protocols work. Although these protocols are relatively simple, it is necessary to analyze many different situations to understand how they address all the details of the problem they solve. This makes them complex to be explained and to be understood. A tool that illustrates graphically the operation of these protocols should greatly facilitate the teaching/learning of these protocols. With the aim of improving the teaching on this subject, we have developed three interactive animations that show how some of the most frequently used cache coherence protocols work. For each protocol, a sequence of read and write operations illustrates all possible situations that can take place in each protocol. The tool is interactive in that the student can go forward and backward to understand/ study the different actions that occur at each step.Este trabajo ha sido parcialmente financiado por el proyecto «Activitats formatives per a assignatures de la matèria Arquitectura de Computadores» de la Unitat de Suport Educatiu de la Universitat Jaume I (10G136-16)