Static analysis of WCET in a satellite software subsystem

This paper describes the authors? experience with static analysis of both WCET and stack usage of a satellite on-board software subsystem. The work is a continuation of a previous case study that used a dynamic WCET analysis tool on an earlier version of the same software system. In particular, the AbsInt aiT tool has been evaluated by analysing both C and Ada code generated by Simulink within the UPMSat-2 project. Some aspects of the aiT tool, specifically those dealing with SPARC register windows, are compared to another static analysis tool, Bound-T. The results of the analysis are discussed, and some conclusions on the use of static WCET analysis tools on the SPARC architecture are commented in the paper.

Time and space partitioning the EagleEye reference mission

We discuss experiences gained by porting a Software Validation Facility (SVF) and a satellite Central Software (CSW) to a platform with support for Time and Space Partitioning (TSP). The SVF and CSW are part of the EagleEye Reference mission of the European Space Agency (ESA). As a reference mission, EagleEye is a perfect candidate to evaluate practical aspects of developing satellite CSW for and on TSP platforms. The specific TSP platform we used consists of a simulate D LEON3 CPU controlled by the XtratuM separation micro-kernel. On top of this, we run five separate partitions. Each partition ru n s its own real-time operating system or Ada run-time kernel, which in turn are running the application software of the CSW. We describe issues related to partitioning; inter-partition communication; scheduling; I/O; and fault-detection, isolation, and recovery (FDIR)

On real-time partitioned multicore systems

Partitioning is a common approach to developing mixed-criticality systems, where partitions are isolated from each other both in the temporal and the spatial domain in order to prevent low-criticality subsystems from compromising other subsystems with high level of criticality in case of misbehaviour. The advent of many-core processors, on the other hand, opens the way to highly parallel systems in which all partitions can be allocated to dedicated processor cores. This trend will simplify processor scheduling, although other issues such as mutual interference in the temporal domain may arise as a consequence of memory and device sharing. The paper describes an architecture for multi-core partitioned systems including critical subsystems built with the Ada Ravenscar profile. Some implementation issues are discussed, and experience on implementing the ORK kernel on the XtratuM partitioning hypervisor is presented.

Ada real-time services and virtualization

Virtualization techniques have received increased attention in the field of embedded real-time systems. Such techniques provide a set of virtual machines that run on a single hardware platform, thus allowing several application programs to be executed as though they were running on separate machines, with isolated memory spaces and a fraction of the real processor time available to each of them.This papers deals with some problems that arise when implementing real-time systems written in Ada on a virtual machine. The effects of virtualization on the performance of the Ada real-time services are analysed, and requirements for the virtualization layer are derived. Virtual-machine time services are also defined in order to properly support Ada real-time applications. The implementation of the ORK+ kernel on the XtratuM supervisor is used as an example.

On the approximate parametrization problem of algebraic curves.

The problem of parameterizing approximately algebraic curves and surfaces is an active research field, with many implications in practical applications. The problem can be treated locally or globally. We formally state the problem, in its global version for the case of algebraic curves (planar or spatial), and we report on some algorithms approaching it, as well as on the associated error distance analysis.

Reglamento para el govierno del Monte-Pio de Viudas, y pupilos de los abogados del ... Colegio de la ciudad de Valencia ... [Texto impreso] : aprobado por los señores del ... Consejo de Castilla, en 20 de Marzo de 1778

Hay un ejemplar encuadernado con: Alegación en hecho y derecho por la... Duquesa del Infantado... posseedora de la Baronia de Alberique... contra el Dr.Juan Fronti,... Felix Pasqual Garcia..., Joseph Ortiz...y demas litis consortes... en el pleyto que pende ante... la Real Audiencia ... (XVIII/510).

Experience in spacecraft on-board software development

This paper describes some important aspects of high- integrity software development based on the authors' work. Current group research is oriented towards mixed- criticality partitioned systems, development tools, real- time kernels, and language features. The UPMSat-2 satellite software is being used as technology demonstra- tor and a case study for the assessment of the research results. The flight software that will run on the satellite is based on proven technology, such as GNAT/ORK+ and LEON3. There is an experimental version that is being built using a partitioned approach, aiming at assessing a toolset targeting partitioned multi-core em- bedded systems. The singularities of both approaches are discussed, as well as some of the tools that are being used for developing the software.

Memory isolation in many-core embedded systems

The current approach to developing mixed-criticality sys- tems is by partitioning the hardware resources (processors, memory and I/O devices) among the different applications. Partitions are isolated from each other both in the temporal and the spatial domain, so that low-criticality applications cannot compromise other applications with a higher level of criticality in case of misbehaviour. New architectures based on many-core processors open the way to highly parallel systems in which each partition can be allocated to a set of dedicated proces- sor cores, thus simplifying partition scheduling and temporal separation. Moreover, spatial isolation can also benefit from many-core architectures, by using simpler hardware mechanisms to protect the address spaces of different applications. This paper describes an architecture for many- core embedded partitioned systems, together with some implementation advice for spatial isolation.

Basement structure of the Hontomín CO2 storage site (Spain) determined by integration of microgravity and 3D seismic data

We dedicate this paper to the memory of Prof. Andres Perez Estaún, who was a great and committed scientist, wonderful colleague and even better friend. The datasets in this work have been funded by Fundación Ciudad de la Energía (Spanish Government, www.ciuden.es) and by the European Union through the “European Energy Programme 15 for Recovery” and the Compostilla OXYCFB300 project. Dr. Juan Alcalde is currently funded by NERC grant NE/M007251/1. Simon Campbell and Samuel Cheyney are acknowledged for thoughtful comments on gravity inversion

Los vínculos existentes entre los recursos hídricos y la sostenibilidad de los sistemas naturales y humanos en la Marina Baixa

Comunicación presentada en el IV Congreso Ibérico sobre Gestión y Planificación del Agua, Tortosa, 8-12 diciembre 2004.

Los poetas argentinos.

t. 1. Dedicatoria.--Carta al espíritu inmortal del Dr. D. Juan M. Gutierrez.--Prefacio.--Síntesis y evolución de nuestra poesia.--Dr. Juan Baltazar Maziel.--Dr. Manuel J. de Labarden.--Dr. Pantaleon Rivarola.--Fray Cayetano J. Rodgiguez.

Peruanos y bolivianos en la sátira chilena de la Guerra del Pacífico (1879 - 1884)

A partir de los grabados publicados en las páginas de los periódicos que incluyeron humor gráfico en sus ediciones durante la Guerra del Pacífico (1879 - 1883), los caricaturistas chilenos desplegaron un discurso visual agresivo en clave patriótica y belicista, donde presentaron a sus lectores una imagen crítica y despectiva respecto de los adversarios de Chile. Recalcaron la supuesta falta de ánimo y valor combativo, ante la sola presencia de los efectivos militares chilenos tanto en el mar como en tierra. Así, la tinta y el papel, se transformaron en otra de las armas que intervinieron en el conflicto de Chile contra el Perú y Bolivia por la posesión de los ricos territorios salitreros de Tarapacá y Antofagasta. Las imágenes fueron interpretadas a partir de los postulados de la Escuela de Warburg, en especial los de Erwin Panofsky, que propone tres niveles de estudio del significado de cada obra, a saber, la “descripción preiconográfica”, luego el “estudio iconográfico” en cuanto tal y, finalmente, la “interpretación iconológica”.

Discontinuidades urbanas

[ES]Propuesta de regeneración urbana y paisajística en el Carrizal de Ingenio, Gran Canaria. 

Se trata de resolver una discontinuidad existente entre el territorio, el límite de la ciudad y el interior de la misma.  A partir de una nueva estructura de espacios públicos y de actuaciones puntuales a modo de piezas arquitectónicas, se soluciona la fractura existente entre la ciudad y el propio territorio.