Strategy for data-flow synchronizations in stencil parallel computations on multi-/manycore systems

In this paper, an innovative strategy for the data-flow synchronization in shared-memory systems is proposed. This strategy assumes to synchronize only interdependent threads instead of using the barrier approach that—in contrast to our approach—synchronize all threads. We demonstrate the adaptation of the data-flow synchronization strategy to two complex scientific applications based on stencil codes. An algorithm for the data-flow synchronization is developed and successfully used for both applications. The proposed approach is evaluated for various Intel microarchitectures released in the last 5 years, including the newest processors: Skylake and Knights Landing. The important part of this assessment is the performance comparison of the proposed data-flow synchronization with the OpenMP barrier. The experimental results show that the performance of the studied applications can be accelerated up to 1.3 times using the proposed data-flow synchronizations strategy.     

Electro-optical properties of diluted GaAsN on GaAs grown by APMOVPE

In this paper we report on the optical and electrical studies of single GaAs_1?x N _x epitaxial layers grown on GaAs substrates by means of atmospheric pressure metal organic vapour phase epitaxy (APMOVPE). Three kinds of samples with 1.2 %, 1.6 % and 2.7 % nitrogen content were studied. Optical properties of the layers were investigated with the use of room temperature transmittance and reflectance measurements. Subsequently Schottky Au-GaAs_1?x N _x contacts were processed and characterized by current-voltage (I-V) and capacitance-voltage (C-V) measurements within 80–480 K temperature range. From the I-V and C-V characteristics the ideality factor, series resistance and built-in potential were determined. Obtained diodes can be used for further studies on defects with the use of DLTS method.     

Chalcones Enhance TRAIL-Induced Apoptosis in Prostate Cancer Cells

Chalcones exhibit chemopreventive and antitumor effects. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a naturally occurring anticancer agent that induces apoptosis in cancer cells and is not toxic to normal cells. We examined the cytotoxic and apoptotic effect of five chalcones in combination with TRAIL on prostate cancer cells. The cytotoxicity was evaluated by the MTT and LDH assays. The apoptosis was determined using flow cytometry with annexin V-FITC. Our study showed that all five tested chalcones: chalcone, licochalcone-A, isobavachalcone, xanthohumol, butein markedly augmented TRAIL-mediated apoptosis and cytotoxicity in prostate cancer cells and confirmed the significant role of chalcones in chemoprevention of prostate cancer.     

Zirconia Layer Formed by High Temperature Oxidation of Pure Zirconium: Stress Generated at the Zirconium/Zirconia Interface

Oxidation of pure zirconium metal at high temperature (500 and 600 °C) under air at normal atmospheric pressure was investigated using the Raman Spectroscopy technique. Analysis of the absolute intensities as well as the positions of the Raman bands for the tetragonal and the monoclinic zirconia phases was performed. Evolution of the thermal stress has been presented and discussed in comparison to the Raman mode shift recorded in situ during cooling. Ex-situ analyses of cross-sections confirm the presence of tetragonal phase preferentially located close to the metal/oxide interface and show the existence of a relaxed and highly disordered tetragonal phase preferentially located in the outer part of the scale. Using a micro tension––compression machine, it is shown that compression loads lead to a significant intensity change of the Raman peaks for the tetragonal zirconia. The effect of tension load appears less clear which demonstrates that the relation between Raman peak shift and stress is not as simple as generally considered.     

Experiment Dashboard for Monitoring Computing Activities of the LHC Virtual Organizations

The Large Hadron Collider (LHC) is preparing for data taking at the end of 2009. The Worldwide LHC Computing Grid (WLCG) provides data storage and computational resources for the high energy physics community. Operating the heterogeneous WLCG infrastructure, which integrates 140 computing centers in 33 countries all over the world, is a complicated task. Reliable monitoring is one of the crucial components of the WLCG for providing the functionality and performance that is required by the LHC experiments. The Experiment Dashboard system provides monitoring of the WLCG infrastructure from the perspective of the LHC experiments and covers the complete range of their computing activities. This work describes the architecture of the Experiment Dashboard system and its main monitoring applications and summarizes current experiences by the LHC experiments, in particular during service challenges performed on the WLCG over the last years.     

Influence of the quantum uncertainty on the two-beams approach of reconstruction for one-photon mixed states of partially polarised light

Abstract

In this paper we discuss the reconstruction process of one-photon mixed states of partially polarised light. To solve this issue, we obtain the Stokes parameters by means of the degree of polarisation. The density operator describing the examined state is represented with these parameters. In the proposed two-beams method the degree of polarisation is measured on the analysed beam combined with reference beams containing photons with a settled state of polarisation. Coupling these beams allows one to obtain the Stokes parameters from the intensity contrast behind the rotating polariser. We discuss the influence of the quantum uncertainty on this technique of one-photon states reconstruction and we consider it for three aspects – the possibility of reducing the number of reference beams that are needed, the optimal state of polarisation of reference beams and the accuracy of the reconstruction method.     

Numerical reconstruction of one-photon mixed states by means of the degree of linear polarisation

In this paper the authors present the idea for reconstructing one-photon states. Reconstructing a quantum state means measuring the probability distribution P that allows one to write the density operator for the analysed state. The most commonly known approach for the quantum reconstruction is the quantum tomography. Our alternative method assumes that the analysed field is coupled with the reference field which is described by the parameters settled during a measurement. In the proposed gedankenexperiment the degree of linear polarisation (DOLP) of this combined beam is measured using a rotating linear polariser. We state that it is possible to obtain the P-function by changing the parameters of reference beams and by preparing the series of DOLP measurements. This series of data leads to the system of equations. The values of the P-function at chosen points are the unknowns of this system. This article focuses on the numerical algorithm for solving these equations.     

Multi billet extrusion technology for manufacturing bi-layered components

The development of the multi billet extrusion technology for manufacturing bi-layered aluminum based semi-products for heat radiators is the subject of this work. To obtain increased strength of the product, ultra fine grained ECAP billets were prepared and used during the extrusion. Appropriate deformation route to get desirable level of grain refinement and billet quality were identified by a series of experiments and numerical simulations performed with the implemented microstructure evolution model. Similar combination of experimental and numerical research was used within the paper for identification of dies geometry and process parameters during development of the multi billet extrusion technology.