Vladimir Sahakyan

A Grid-Aware Web Portal with Advanced Service Trading for Linear Algebra Calculations

Due to the rapid growth of the Internet, there has been a rising interest in using the Web as an interface to develop various applications over computational Grid environments. The purpose of this work is to develop a Grid-aware Web interface for linear algebra tasks with advanced service trading. Developing efficient and portable codes, requires users to face parallel computing and programming and to make use of different standard libraries, such as the BLAS [1], LAPACK [2] and ScaLAPACK [3] in order to solve computational tasks related to linear algebra. For this purpose, a scientific computing environment based on a Web interface is described that allows users to perform their linear algebra tasks without explicitly calling the above mentioned libraries and softwarep tools, as well as without installing any piece of software on local computers: users enter algebraic formula (such as in Matlab or Scilab [4]) that are evaluated for determining the combinations of services answering the user request. Services are then executed locally or over the Grid using the Distributed Interactive Engineering Toolbox (DIET) [5] middleware.

On the Easy Use of Scientific Computing Services for Large Scale Linear Algebra and Parallel Decision Making with the P-Grade Portal

Scientific research is becoming increasingly dependent on the large-scale analysis of data using distributed computing infrastructures (Grid, cloud, GPU, etc.). Scientific computing (Petitet et al. 1999) aims at constructing mathematical models and numerical solution techniques for solving problems arising in science and engineering. In this paper, we describe the services of an integrated portal based on the P-Grade (Parallel Grid Run-time and Application Development Environment) portal (http://www.p-grade.hu) that enables the solution of large-scale linear systems of equations using direct solvers, makes easier the use of parallel block iterative algorithm and provides an interface for parallel decision making algorithms. The ultimate goal is to develop a single sign on integrated multi-service environment providing an easy access to different kind of mathematical calculations and algorithms to be performed on hybrid distributed computing infrastructures combining the benefits of large clusters, Grid or cloud, when needed.

Introduction of a Grid-aware portlet for numerical calculations

Grid portals are one of the most popular user interfaces to Grids. Grid portals build upon the familiar Web portal model offer to virtual communities of users a single access point to computational or data resources. P-GRADE is a Grid portal solution that allows users to manage the whole life-cycle for executing a parallel application in the Grid. The purpose of this article is to introduce the structure of a Grid-aware portlet for linear algebra calculations based on the P-GRADE portal. To accomplish this goal, the portlet provides the seamless bridge between the linear algebra calculations and various linear algebra software environments (middlewares, tools, parallel programming techniques, linear algebra libraries) deployed over a grid. The portlet GUI (Graphical User Interface) is lightweight and uses standard web technologies. Moreover, since today smartphone are ubiquitous, we propose to provide an easy and adapted way to monitor the portlets operation from a mobile device and illustrate its practical use.

Enabling Large-Scale Linear Systems of Equations on Hybrid HPC Infrastructures

Scientific research is becoming increasingly dependent on the large-scale analysis of data using High Performance Computing (HPC) infrastructures. Scientific computing aims at constructing mathematical models and numerical solution techniques for solving problems arising in science and engineering. The solution of linear system of equations lies at the heart of most calculations in scientific computing. HPC infrastructures with many-core and graphics processing unit (GPU) challenges, Cloud and Grid technologies and e-infrastructures are currently offering interesting opportunities for solving large-scale linear system of equations. In this article, a second-generation of our Web portal for Scientific Computing is introduced based on a hybrid HPC infrastructure that provides predictable optimal execution and scales from a single resource to multiple resources. After analyzing the synergies and the complementarities of the different computing platforms, we argue for an architecture that combines the benefits of these technologies.

WRF-ARW Model for Prediction of High Temperatures in South and South East Regions of Armenia

The ultimate goal of the study is to develop an early warning system for the south and southeast regions of Armenia (11 in total) by defining specific thresholds for issuing alerts for adverse and severe weather phenomena. In the article the high temperature, wind and precipitation weather elements are discussed based on the experiments performed during the summer periods of 2011 and 2014. The system has been implemented based on the mesoscale Weather Research and Forecasting (WRF) model [1], which is adapted to the territory of Armenia and used for operational weather forecasting. The verification methodology is to analyze the model results against observations received from four ground hydrometeorological stations located in the south and southeast regions of Armenia. The correlation coefficients, standard deviations of the differences and biases are calculated for the air temperature and wind speed and for precipitation amount and yes/no contingency tables are constructed.