HW/SW codesign techniques for dynamically reconfigurable architectures

Hardware/software (HW/SW) codesign and reconfigurable computing are commonly used methodologies for digital-systems design. However, no previous work has been carried out in order to define a HW/SW codesign methodology with dynamic scheduling for run-time reconfigurable architectures. In addition, all previous approaches to reconfigurable computing multicontext scheduling are based on static-scheduling techniques. In this paper, we present three main contributions: 1) a novel HW/SW codesign methodology with dynamic scheduling for discrete event systems using dynamically reconfigurable architectures; 2) a new dynamic approach to reconfigurable computing multicontext scheduling; and 3) a HW/SW partitioning algorithm for dynamically reconfigurable architectures. We have developed a whole codesign framework, where we have applied our methodology and algorithms to the case study of software acceleration. An exhaustive study has been carried out, and the obtained results demonstrate the benefits of our approach.     

Convergence to Suitable Weak Solutions for a Finite Element Approximation of the Navier–Stokes Equations with Numerical Subgrid Scale Modeling

In this article, a Galerkin finite element approximation for a class of time–space fractional differential equation is studied, under the assumption that \(u_{tt}, u_{ttt}, u_{2\alpha ,tt}\) are continuous for \(\varOmega \times (0,T]\), but discontinuous at time \(t=0\). In spatial direction, the Galerkin finite element method is presented. And in time direction, a Crank–Nicolson time-stepping is used to approximate the fractional differential term, and the product trapezoidal method is employed to treat the temporal fractional integral term. By using the properties of the fractional Ritz projection and the fractional Ritz–Volterra projection, the convergence analyses of semi-discretization scheme and full discretization scheme are derived separately. Due to the lack of smoothness of the exact solution, the numerical accuracy does not achieve second order convergence in time, which is \(O(k^{3-\beta }+k^{3}t_{n+1}^{-\beta }+k^{3}t_{n+1}^{-\beta -1})\), \(n=0,1,\ldots ,N-1\). But the convergence order in time is shown to be greater than one. Numerical examples are also included to demonstrate the effectiveness of the proposed method.     

Protection of high‐density polyethylene–silicon composites from ultraviolet–visible photodegradation

The extent of the ultraviolet–visible (UV–vis) photoirradiation effect on high‐density polyethylene (HDPE) and HDPE–silicon (Si) composites is reported in terms of the addition of Si microparticles at contents of 0.1, 1, and 5 wt %. A standard accelerated UV–vis exposure was applied over 2750 h, corresponding to 22 months in Florida. Thermogravimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopy were used as reliable techniques for monitoring the quality of the HDPE–Si composites. The increasing addition of Si microparticles delayed the photodegradation of the HDPE–Si composites. Because of their strong light‐scattering effects, Si microparticles blocked the degradation of tertiary carbons of the HDPE backbone and reduced the apparition of vinyl groups; this prevented the structural impoverishment of HDPE–Si composites. Consequently, variations in the crystallization temperature (T_c) and melting temperature (T_m), which were indicators of photodegradation, were not modified. In general, the HDPE–Si composite formulation with 5 wt % Si microparticles was useful for protecting the material from photodegradation and, thus, should be an environmentally friendly, reliable alternative UV–vis blocker. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45439.     

Cell-to-Cell Communication by Host-Released Extracellular Vesicles in the Gut: Implications in Health and Disease

Communication between cells is crucial to preserve body homeostasis and health. Tightly controlled intercellular dialog is particularly relevant in the gut, where cells of the intestinal mucosa are constantly exposed to millions of microbes that have great impact on intestinal homeostasis by controlling barrier and immune functions. Recent knowledge involves extracellular vesicles (EVs) as mediators of such communication by transferring messenger bioactive molecules including proteins, lipids, and miRNAs between cells and tissues. The specific functions of EVs principally depend on the internal cargo, which upon delivery to target cells trigger signal events that modulate cellular functions. The vesicular cargo is greatly influenced by genetic, pathological, and environmental factors. This finding provides the basis for investigating potential clinical applications of EVs as therapeutic targets or diagnostic biomarkers. Here, we review current knowledge on the biogenesis and cargo composition of EVs in general terms. We then focus the attention to EVs released by cells of the intestinal mucosa and their impact on intestinal homeostasis in health and disease. We specifically highlight their role on epithelial barrier integrity, wound healing of epithelial cells, immunity, and microbiota shaping. Microbiota-derived EVs are not reviewed here.     

<Emphasis FontCategory="NonProportional">FEMPAR</Emphasis>: An Object-Oriented Parallel Finite Element Framework

FEMPAR is an open source object oriented Fortran200X scientific software library for the high-performance scalable simulation of complex multiphysics problems governed by partial differential equations at large scales, by exploiting state-of-the-art supercomputing resources. It is a highly modularized, flexible, and extensible library, that provides a set of modules that can be combined to carry out the different steps of the simulation pipeline. FEMPAR includes a rich set of algorithms for the discretization step, namely (arbitrary-order) grad, div, and curl-conforming finite element methods, discontinuous Galerkin methods, B-splines, and unfitted finite element techniques on cut cells, combined with h-adaptivity. The linear solver module relies on state-of-the-art bulk-asynchronous implementations of multilevel domain decomposition solvers for the different discretization alternatives and block-preconditioning techniques for multiphysics problems. FEMPAR is a framework that provides users with out-of-the-box state-of-the-art discretization techniques and highly scalable solvers for the simulation of complex applications, hiding the dramatic complexity of the underlying algorithms. But it is also a framework for researchers that want to experience with new algorithms and solvers, by providing a highly extensible framework. In this work, the first one in a series of articles about FEMPAR, we provide a detailed introduction to the software abstractions used in the discretization module and the related geometrical module. We also provide some ingredients about the assembly of linear systems arising from finite element discretizations, but the software design of complex scalable multilevel solvers is postponed to a subsequent work.     

Towards Mobile Cloud Computing with Single Sign-on Access

The low computing power of mobile devices impedes the development of mobile applications with a heavy computing load. Mobile Cloud Computing (MCC) has emerged as the solution to this by connecting mobile devices with the “infinite” computing power of the Cloud. As mobile devices typically communicate over untrusted networks, it becomes necessary to secure the communications to avoid privacy-sensitive data breaches. This paper presents work on implementing MCC applications with secure communications. For that purpose, we built on COMPSs-Mobile, a redesigned implementation of the COMP Superscalar (COMPSs) framework aiming to MCC platorms. COMPSs-Mobile automatically exploits the parallelism inherent in an application and orchestrates its execution on loosely-coupled distributed environment. To avoid a vendor lock-in, this extension leverages on the Generic Security Services Application Program Interface (GSSAPI) (RFC2743) as a generic way to access security services to provide communications with authentication, secrecy and integrity. Besides, GSSAPI allows applications to take profit of more advanced features, such as Federated Identity or Single Sign-On, which the underlying security framework could provide. To validate the practicality of the proposal, we use Kerberos as the security services provider to implement SSO; however, applications do not authenticate themselves and require users to obtain and place the credentials beforehand. To evaluate the performance, we conducted some tests running an application on a smartphone offloading tasks to a private cloud. Our results show that the overhead of securing the communications is acceptable.     

Information problem‐solving skills in small virtual groups and learning outcomes

This study investigated the frequency of use of information problem‐solving (IPS) skills and its relationship with learning outcomes. During the course of the study, 40 teachers carried out a collaborative IPS task in small virtual groups in a 4‐week online training course. The status of IPS skills was collected through self‐reports handed in over the course of the 4 weeks. Learning was evaluated by means of open‐ended questionnaires before and after the group task. Three types of knowledge learning were evaluated: declarative, procedural and situational. Teachers exhibited a recurrent use of all skills during the whole collaborative task, although periodic use differed from week to week. Results showed a relationship between some IPS skills and declarative and procedural knowledge. The skills that were statistically significant were share information, read peer's information and analyse information. Implications for learning support and instruction are discussed.     

A study on the optimum insulation thicknesses of building walls with respect to different zones in Morocco

Morocco has very limited indigenous energy resources; consequently, with the increase in energy consumption over the last years, studies focusing on energy saving as well as usage of sustainable energy resources have accelerated. However, in Morocco the buildings have an important part in the energy consumption; therefore, the most logical solution is energy saving by using thermal insulation. For this purpose, in this study, six cities, namely Agadir, Tangier, Fez, Ifran, Marrakech and Errachidia are selected to represent the six zones of Morocco. Using the life-cycle cost analysis method, the optimum insulation thicknesses as well as energy savings and payback periods for electricity tariff and three different types of insulation material have been determined.