National Technical University of Athens

About: National Technical University of Athens is a education organization based out in Athens, Attiki, Greece. It is known for research contribution in the topics: Large Hadron Collider & Nonlinear system. The organization has 13445 authors who have published 31259 publications receiving 723504 citations. The organization is also known as: Athens Polytechnic & NTUA.

RELEASE: A High-Level Paradigm for Reliable Large-Scale Server Software - (Project Paper).

Abstract: Erlang is a functional language with a much-emulated model for building reliable distributed systems. This paper outlines the RELEASE project, and describes the progress in the first six months. The project aim is to scale the Erlang's radical concurrency-oriented programming paradigm to build reliable general-purpose software, such as server-based systems, on massively parallel machines. Currently Erlang has inherently scalable computation and reliability models, but in practice scalability is constrained by aspects of the language and virtual machine. We are working at three levels to address these challenges: evolving the Erlang virtual machine so that it can work effectively on large scale multicore systems; evolving the language to Scalable Distributed SD Erlang; developing a scalable Erlang infrastructure to integrate multiple, heterogeneous clusters. We are also developing state of the art tools that allow programmers to understand the behaviour of massively parallel SD Erlang programs. We will demonstrate the effectiveness of the RELEASE approach using demonstrators and two large case studies on a Blue Gene.

Optimization of β-glucosidase catalysed synthesis of trisaccharides from cellobiose and gentiobiose

Abstract: Purified β-Glucosidase from Fusarium oxysporum catalysed the hydrolysis and transglycosylation reactions in the presence of cellobiose and gentiobiose The product of the latter reaction was mainly a triose The time of incubation, pH and substrate concentration for transglycosylation reaction were optimised Under optimal conditions, the concentration of glucose and triose reached approximately 15–20 % of the initial substrate concentration These results suggested that β-glucosidase from Foxysporum is an ideal enzyme for the synthesis of triose in reasonable quantities

Probabilistic Load Flow methods with high integration of Renewable Energy Sources and Electric Vehicles - case study of Greece

Abstract: This paper exams the large distribution power system of Greece with high integration of Renewable Energy Resources (RES) and Electrical Vehicles (EV) using Probabilistic Load Flow (PLF) techniques. These techniques provide Cumulative Density Functions (CDF) of branch power flows, node voltages and active power line losses with large variations of RES and EV integration. When different charging strategies of EV (dump charging, dual tariff policy and mixed charging) take place then lead to significant uncertainty in node injections. In order to tackle this issue, it is adopted and enhanced PLF methods to cope with EV nodal loads. Two methods are investigated for the calculation of Probabilistic Density Function (PDF) of RES' production, Gram - Charlier (G-C) and Cornish Fisher (C-F). All the PLF results are compared with Monte Carlo (MC) method.

Hydroelastic analysis of ice shelves under long wave excitation

Abstract: . The transient hydroelastic response of an ice shelf under long wave excitation is analysed by means of the finite element method. The simple model, presented in this work, is used for the simulation of the generated kinematic and stress fields in an ice shelf, when the latter interacts with a tsunami wave. The ice shelf, being of large length compared to its thickness, is modelled as an elastic Euler-Bernoulli beam, constrained at the grounding line. The hydrodynamic field is represented by the linearised shallow water equations. The numerical solution is based on the development of a special hydroelastic finite element for the system of governing of equations. Motivated by the 2011 Sulzberger Ice Shelf (SIS) calving event and its correlation with the Honshu Tsunami, the SIS stable configuration is studied. The extreme values of the bending moment distribution in both space and time are examined. Finally, the location of these extrema is investigated for different values of ice shelf thickness and tsunami wave length.