Hartwig Anzt  Jack Dongarra  Goran Flegar  Nicholas J. Higham  Enrique S. Quintana‐Ortí 《Concurrency and Computation》2019,31(6)

We propose an adaptive scheme to reduce communication overhead caused by data movement by selectively storing the diagonal blocks of a block‐Jacobi preconditioner in different precision formats (half, single, or double). This specialized preconditioner can then be combined with any Krylov subspace method for the solution of sparse linear systems to perform all arithmetic in double precision. We assess the effects of the adaptive precision preconditioner on the iteration count and data transfer cost of a preconditioned conjugate gradient solver. A preconditioned conjugate gradient method is, in general, a memory bandwidth‐bound algorithm, and therefore its execution time and energy consumption are largely dominated by the costs of accessing the problem's data in memory. Given this observation, we propose a model that quantifies the time and energy savings of our approach based on the assumption that these two costs depend linearly on the bit length of a floating point number. Furthermore, we use a number of test problems from the SuiteSparse matrix collection to estimate the potential benefits of the adaptive block‐Jacobi preconditioning scheme.  相似文献   

    

Jorge A. Pino  Odri Sosa-Moguel  Enrique Sauri-Duch  Luis Cuevas-Glory 《Journal of Food Processing and Preservation》2019,43(10):e14136

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Leonardo Romero-Martínez  Paola Duque-Sarango  Asunción Acevedo-Merino  Enrique Nebot 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2019,94(9):2980-2989

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Agustina Eberhardt  Emilse C Lpez  Roberto J Ceruti  Fernanda Marino  Enrique J Mammarella  Ricardo M Manzo  Guillermo A Sihufe 《International Journal of Dairy Technology》2019,72(4):573-584

Whey protein concentrate was enzymatically hydrolysed at several time courses using the commercial preparation Alcalase^® 2.4 L, different hydrolysates were achieved, and the effect of degree of hydrolysis (DH) on both technological and biological properties was studied. Results have shown that solubility, antioxidant and ACE inhibition activities were increased as DH was also augmented from about 8 to 17%. RP‐HPLC studies also revealed a decrease in hydrophobicity when samples were hydrolysed in comparison with controls. When the enzyme hydrolytic action was augmented, it stimulated both the bioactivity of whey protein and relevant technological properties, allowing these hydrolysates to be employed as additives in the development of food formulations.  相似文献   

    

Tulio A. Lerma  Manuel Palencia  Enrique M. Combatt 《应用聚合物科学杂志》2018,135(18)

The constant deterioration of the soil as a result of natural and anthropogenic processes produces decrease of soil fertility and agricultural production, increase in the cost of food, desertification, and loss of water resources. The objective of this work was to develop a hybrid composite that structural and functionally mimics the humified structure of soils for the development of remediation strategies based on geotransformation of degraded soils. For that, two different strategies for the modification of clay surface were evaluated: (i) covalent linking using trichlorovinylsilane and (ii) electrostatic interaction using N‐vinylbenzyl‐N‐triethyl ammonium chloride. Later, modified clay was characterized and used as crosslinking agent during the free‐radical polymerization of acrylic acid. Particulate nanostructured polymers were characterized and their water absorption capacity, cationic exchange capacity, and ionic retention capacity were determined. Results showed that clay‐poly(acrylic acid) composites can be obtained by described methodology. In addition, materials with 60 and 80% w/w of modified MMT were obtained with particulate shape, high water absorption capacity (273%–568%), high cationic exchange capacity (124–666 meq+/100 g) and high ionic retention capacity (108–194 and 263–313 meq/100 g for major and minor elements, respectively). Finally, it was concluded that synthesized materials mimic structural and functionally the humified structure of soils. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46211.  相似文献   

    

Ivan J Tolano‐Villaverde  Victor Ocaño‐Higuera  Josafat Ezquerra‐Brauer  Irela Santos‐Sauceda  Hisila Santacruz‐Ortega  José L Cárdenas‐López  Guillermo Rodríguez‐Olibarria  Enrique Márquez‐Ríos 《Journal of the science of food and agriculture》2018,98(5):1787-1793

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Enrique Montes  Udo Schwingenschlgl 《Advanced materials (Deerfield Beach, Fla.)》2019,31(18)

The electronic properties of black and blue phosphorus nanoribbons are investigated, which enables the proposal of junction‐free field‐effect transistors that comprise metallic armchair nanoribbons as electrodes and, in between, a semiconducting zigzag nanoribbon as channel material (cut out of a single sheet of monolayer black or blue phosphorus). Using first‐principles calculations and the nonequilibrium Green's function method, the proposed field‐effect transistors are characterized. It is found that it is possible to achieve outstanding performance, with high on/off ratios, low subthreshold swings, and high transconductances.  相似文献   

    

Jos A. Lpez‐Campos  Abraham Segade  Enrique Casarejos  Jos R. Fernndez 《Computational and Mathematical Methods》2019,1(1)

In this study, we have been working within the framework of mathematical characterization of materials with complex behavior, and we used this characterization as input data for simulations in finite elements codes. We have researched the behavior of hyperelastic materials with viscoelastic qualities. There are models for the characterization of this type of materials; however, they lean on parameters that have to be previously determined for each material, and only then, their calculation models can estimate an answer for each material under specific loading conditions. We have focused on the viscoelastic characterization applying Prony series for finite elements simulations. We have developed a procedure to obtain the adequate number of terms of the series as well as the coefficients of characterization from a relaxation spectrum generated by a rheological model. We expect that this new procedure can effectively help researchers in the characterization of materials using Prony series and hence be implemented for later use of it in programs of finite elements.  相似文献   

    

Francisco A. Crdenas‐Lpez  Mikel Sanz  Juan Carlos Retamal  Enrique Solano 《Advanced Quantum Technologies》2019,2(7-8)

The quantum synchronization between a pair of two‐level systems inside two coupled cavities is studied. By using a digital–analog decomposition of the master equation that rules the system dynamics, it is shown that this approach leads to quantum synchronization between both two‐level systems. Moreover, in this digital–analog block decomposition, the fundamental elements of a quantum machine learning protocol can be identified, in which the agent and the environment (learning units) interact through a mediating system, namely, the register. If the algorithm can be additionally equipped with a classical feedback mechanism, which consists of projective measurements in the register, reinitialization of the register state, and local conditional operations on the agent and environment subspace, a powerful and flexible quantum machine learning protocol emerges. Indeed, numerical simulations show that this protocol enhances the synchronization process, even when every subsystem experiences different loss/decoherence mechanisms, and gives the flexibility to choose the synchronization state. Finally, an implementation is proposed, based on current technologies in superconducting circuits.  相似文献   

    

Sergey Kovalev  Mikhail Y. Kovalyov  Gur Mosheiov  Enrique Gerstl 《国际生产研究杂志》2019,57(2):560-566

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