Nabil Abdennadher

Reliable Software Technologies – Ada Europe 2007

Real-Time Utilities for Ada 2005.- Handling Temporal Faults in Ada 2005.- Implementation of New Ada 2005 Real-Time Services in MaRTE OS and GNAT.- Enhancing Dependability of Component-Based Systems.- On Detecting Double Literal Faults in Boolean Expressions.- Static Detection of Livelocks in Ada Multitasking Programs.- Towards the Testing of Power-Aware Software Applications for Wireless Sensor Networks.- An Intermediate Representation Approach to Reducing Test Suites for Retargeted Compilers.- Correctness by Construction for High-Integrity Real-Time Systems: A Metamodel-Driven Approach.- A Metamodel-Driven Process Featuring Advanced Model-Based Timing Analysis.- ArchMDE Approach for the Development of Embedded Real Time Systems.- Generating Distributed High Integrity Applications from Their Architectural Description.- Automatic Ada Code Generation Using a Model-Driven Engineering Approach.- Towards User-Level Extensibility of an Ada Library: An Experiment with Cheddar.- Modelling Remote Concurrency with Ada.- Design and Performance of a Generic Consensus Component for Critical Distributed Applications.- Sancta: An Ada 2005 General-Purpose Architecture for Mobile Robotics Research.- Incorporating Precise Garbage Collection in an Ada Compiler.

Deploying PHYLIP phylogenetic package on a Large Scale Distributed System

This paper describes the parallelization (gridification) of the phylogenetic package PHYLIP on a large scale distributed system termed XtremWeb- CH. PHYLIP is a package of programs for inferring phylogenies (evolutionary trees). It is the most widely- distributed phylogeny package. PHYLIP has been used to build the largest number of published trees. Its known that some modules of PHYLIP are CPU time consuming; their sequential version can not be applied to a large number of sequences. XtremWeb-CH (XWCH) is a software system that makes it easier for scientists and industrials to deploy and execute their parallel and distributed applications on a public-resource computing infrastructure. Universities, research centres and private companies can create their own XWCH platform while anonymous PC owners can participate to these platforms. They can specify how and when their resources could be used. The objective of XWCH is to develop a real high performance peer-to-peer platform with a distributed scheduling and communication system. The main idea is to build a completely symmetric model where nodes can be providers and consumers at the same time. In this paper we describe the porting, deployment, and execution of some PHYLIP modules on the XWCH platform. The parallelized version of PHYLIP is used to generate evolutionary tree related to HIV viruses.

Virtual EZ Grid: A Volunteer Computing Infrastructure for Scientific Medical Applications

This paper presents the Virtual EZ Grid project, based on the XtremWeb-CH XWCH volunteer computing platform. The goal of the project is to introduce a flexible distributed computing system, with i an infrastructure with a non-trivial amount of computing resources from various institutes, ii a stable platform that manages these computing resources and provides advanced interfaces for applications, and iii a set of applications that take benefit of the platform. This paper concentrates on the application support of the new version of XWCH, and describes how two medical applications, MedGIFT and NeuroWeb, utilise it.

A scheduling algorithm for high performance peer-to-peer platform

This paper describes a scheduling algorithm used to execute parallel and distributed applications on a Global Computing (GC) environment, called XtremWeb-CH (XWCH). XWCH is an improved version of a GC tool called XtremWeb (XW). XWCH is an enrichment of XW allowing it to match P2P concepts: distributed scheduling, distributed communication and development of symmetrical models. The scheduling algorithm takes into account the heterogeneity and volatility of nodes. This paper illustrates the performance of XWCH in a real CPU time consuming application.

A Hybrid Grid/Cloud Distributed Platform: A Case Study

The scene of the computational sciences has considerably changed during the last years. Today, new emerging Desktop grid and Cloud e-infrastructure have a considerable potential to be adopted and used in large scale to exploit thousands of CPUs power to run both scientific and commercial applications. This paper targets scientists and programmers who need to accelerate their scientific research by running their applications on distributed Grid/Cloud infrastructures. We present a hybrid Grid/Cloud platform used to deploy a phylogeny application called MetaPIGA. The aim is to combine the advantages of Grid and Cloud architectures in order to set up a robust, reliable and open platform. We propose two scenarios.

Virtual EZ grid : a volunteer computing infrastructure for scientific medical applications

This paper presents the Virtual EZ Grid project, based on the XtremWeb-CH (XWCH) volunteer computing platform The goal of the project is to introduce a flexible distributed computing system, with (i) a non-trivial number of computing resources infrastructure from various institutes, (ii) a stable platform that manages these computing resources and provides advanced interfaces for applications, and (iii) a set of applications that take benefit of the platform This paper concentrates on the application support of the new version of XWCH, and describes how a medical image application MedGIFT utilises it.

Services Pricing: A Shared Grid Case Study

In recent years much research has gone in grid computing and building shared resource networks. The grid computing has given access to the research community to high computational resources. The pricing of grid resources has been evolved along with resource management however there is a need for a better pricing model which is well suited for services. In this paper, we first explain the notion of service pricing in the context of shared grid computing. Then, we propose an original development of a mathematical programming model based on Markov Decision Processes (MDP) in order to maximize grid service level. An example written in AMPL modeling language is provided.

A WOS/sup TM/-based solution for high performance computing

Most of the development environments for high performance parallel applications require that all the computing modules and resources be known in advance. The execution environment must know where the different program modules will be executed, and must properly configure each computer involved in the execution. We describe how the Web Operating System (WOS/sup TM/) environment may be used to dynamically adjust the granularity of parallel programs, locate available computers to perform the computations and how these computers are dynamically configured. The WOS (P. Kropf et al., 2000) is a metacomputing environment suitable for supporting and managing distributed parallel processing on wide and local networks. Communication between WOS nodes is realized through a generic service protocol (WOSP) and a discovery/location protocol (WOSRP). WOSP may be versioned to support specialized services. The authors focus on the design of two such versions for parallel/distributed applications and high performance computing. These versions support the location and setup of computational nodes for these applications.

Solar Energy Potential Assessment on Rooftops and Facades in Large Built Environments Based on LiDAR Data, Image Processing, and Cloud Computing. Methodological Background, Application, and Validation in Geneva (Solar Cadaster)

The paper presents the core methodology for assessing solar radiation and energy production on building rooftops and vertical facades (still rarely considered) of the inner-city. This integrated tool is based on the use of LiDAR, 2D and 3D cadastral data. Together with solar radiation and astronomical models it calculates the global irradiance for a set of points located on roofs, ground and facades. Although the tool takes simultaneously roofs, ground and facades, different methods of shadow casting are applied. Shadow casting on rooftops is based on image processing techniques. On the other hand, the assessment on facade involves first to create and interpolate points along the facades and then to implement a point-by-point shadow casting routine. The paper is structured in five parts: (i) state of the art on the use of 3D GIS and automated processes in assessing solar radiation in the built environment, (ii) overview on the methodological framework used in the paper, (iii) detailed presentation of the method proposed for solar modelling and shadow casting, in particular by introducing an innovative approach for modelling the Sky View Factor (SVF), (iv) demonstration of the solar model introduced in this paper through applications in Geneva’s building roofs (solar cadaster) and facades, (v) validation of the solar model in some Geneva’s spots, focusing especially on two distinct comparisons: solar model versus fisheye catchments on partially inclined surfaces (roof component); solar model versus photovoltaic simulation tool PVSyst on vertical surfaces (facades). Concerning the roof component, validation results emphasize global sensitivity related to the density of light sources on the sky vault to model the SVF. The low dense sky model with 145 light sources gives satisfying results, especially when processing solar cadasters in large urban areas, thus allowing to save computation time. In the case of building facades, introducing weighting factor in SVF calculation leads to outputs close to those obtained by PVSyst. Such good validation results make the proposed model a reliable tool to: (i) automatically process solar cadaster on building rooftops and facades at large urban scales, (ii) support solar energy planning and energy transition policies.

Solar Cadaster of Geneva: A Decision Support System for Sustainable Energy Management

Cities play an increasingly important role with regards to energy transition. Main goal is to reach international and national (Swiss) targets related to energy efficiency and CO2 emission reduction. As a contribution to these global challenges, during the last 6 years the State of Geneva has been producing a detailed solar cadaster. In order to facilitate periodical updates of this solar cadaster, the iCeBOUND project was launched. Around 10 public and private stakeholders, all linked within the Geneva Territorial Information System (SITG), collaborated on the project. Its aim was to design and develop a cloud-based Decision Support System (DSS) that leverages 3D digital urban data with high computing performance, hence facilitating environmental analyses in large built areas, like solar energy potential assessment. As result of the project, an official geoportal and a newfangled public web interface were made widely available early 2017, so as to strengthen decision making with regards to solar installation investment.