Benchmarking communication middleware for cloud computing virtualizers

REACTION 2013. 2nd International Workshop on Real-time and distributed computing in emerging applications. December 3rd, 2013, Vancouver, Canada.Virtualization technologies typically introduce additional overhead that is specially challenging for specific domains such as real-time systems. One of the sources of overhead are the additional software layers that provide parallel execution environments which reduce the effective performance given by the infrastructure. This work identifies the factors to be analysed by a benchmark for performance evaluation of a virtualized middleware. It provides the set of benchmark tests that evaluate empirically the overhead and stability on a trendy communication middleware, DDS (Data Distribution System for Real-Time), which enables message transmissions via publisher-subscriber (P/S) interactions. Two different implementations, RTI and OpenSplice, have been analysed over a general purpose virtual machine monitor to evaluate their behavior on a client-server application. Obtained results have provided initial execution clues on the performance that a virtualized communication middleware like DDS can exhibit

Using UML for learning how to design and model cyber-physical systems

In this paper a methodology for teaching and learn-ing the modeling of embedded systems and, in a more genericvision cyber-physical systems (CPS) is presented. To this end, asubset of tools from UML is used in an intuitive and orderedway starting with an informal description of the system untilimplementation details are obtained. However, the codificationof the system is left out as the programming language dependson the hardware platform to be used. The method has beenused in grade courses for several years now with an importantaccumulated experience that shows how students are able toadopt it and learn to elicit the different types of requirements,actors and functions.Fil: Ordinez, Leonardo Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Eggly, Gabriel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Micheletto, Matías Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Santos, Rodrigo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentin

Ingeniería basada en modelos aplicada a sistemas distribuidos sensibles al contexto.

239 p.En esta Tesis Doctoral se plantea una metodología, soportada por mecanismos y herramientas, que da soporte al ciclo de desarrollo de aplicaciones distribuidas sensibles al contexto, aquéllas que supervisan su entorno físico con objeto de detectar cambios en él y reaccionar rápida y adecuadamente. Son aplicaciones presentes en diferentes campos de aplicación que demandan requisitos tales como ejecución en entornos distribuidos y heterogéneos, personalización de la supervisión, adaptación a cambios relevantes en su contexto, gestión de la calidad específica de cada aplicación, disponibilidad y recuperación ante situaciones de fallo. En concreto, se propone una aproximación de modelado genérica que permite la especificación y diseño de estas aplicaciones, independientemente de la plataforma de gestión responsable de su ejecución y atendiendo a los diferentes expertos que participan: expertos de dominio y desarrolladores de software. Se hace uso de la ingeniería dirigida por modelos para lograr la separación de dominios necesaria. Así, el experto de dominio realiza el diseño arquitectónico en el que se especifican todos sus requisitos, mientras que el desarrollador de software se centra en el diseño e implementación de la solución software correspondiente. Por tanto, la aproximación de modelado recoge los requisitos de las aplicaciones que una plataforma de gestión debe cumplir en tiempo de ejecución, al mismo tiempo que captura la información necesaria para la generación de su código. También se plantea un entorno de desarrollo integrado, basado en dicha aproximación, que da soporte al ciclo de desarrollo, cuyo prototipo se ha validado en un demostrador en el campo de la asistencia domiciliaria

n-Dimensional Prediction of RT-SOA QoS

Service-Orientation has long provided an effective mechanism to integrate heterogeneous systems in a loosely coupled fashion as services. However, with the emergence of Internet of Things (IoT) there is a growing need to facilitate the integration of real-time services executing in non-controlled, non-real-time, environments such as the Cloud. As such there has been a drive in recent years to develop mechanisms for deriving reliable Quality of Service (QoS) definitions based on the observed performance of services, specifically in order to facilitate a Real-Time Quality of Service (RT-QoS) definition. Due to the overriding challenge in achieving this is the lack of control over the hosting Cloud system many approaches either look at alternative methods that ignore the underlying infrastructure or assume some level of control over interference such as the provision of a Real-Time Operating System (RTOS). There is therefore a major research challenge to find methods that facilitate RT-QoS in environments that do not provide the level of control over interference that is traditionally required for real-time systems. This thesis presents a comprehensive review and analysis of existing QoS and RT-QoS techniques. The techniques are classified into seven categories and the most significant approaches are tested for their ability to provide QoS definitions that are not susceptible to dynamic changing levels of interference. This work then proposes a new n-dimensional framework that models the relationship between resource utilisation, resource availability on host servers, and the response-times of services. The framework is combined with real-time schedulability tests to dynamically provide guarantees on response-times for ranges of resource availabilities and identifies when those conditions are no longer suitable. The proposed framework is compared against the existing techniques using simulation and then evaluated in the domain of Cloud computing where the approach demonstrates an average overallocation of 12%, and provides alerts across 94% of QoS violations within the first 14% of execution progress

Component Framework for supporting safe and dynamic replacement in real-time systems

[EN] In the last decades solutions have been provided for the real- time component-based systems development as a base to increase productivity and reliability of their development as well as their maintenance. Solutions are increasingly appearing that allow controlled flexibility in these systems, aiming to support dynamic execution through the component replacement at run-time. So, component models are adapted trying to minimize conflicts integrating real-time and dynamic behaviors, and achieving components replacements in a bounded time. One of the main challenges for this is to calculate the required times by the different operations needed in a component replacement. The other issue is to know the operating times of the component in the system when their implementations change along the life of the system. In this work the implementation of a component framework implementation is described providing a partial solution for these problems. A component model is provided together with the corresponding algorithms to assure that components can be loaded and replaced at run-time without interfering in their execution deadlines. The model is designed to avoid failures during component replacements. Finally a validation of the presented concepts is provided.[ES] En las últimas décadas se han aportado soluciones para el desarrollo de sistemas de tiempo real basados en componentes como base para aumentar la productividad y la fiabilidad de su desarrollo así como su posterior mantenimiento. De modo más reciente están apareciendo soluciones que permiten cierta flexibilidad en estos sistemas con miras a soportar ejecución dinámica a través de reemplazos de componentes en tiempo de ejecución. Para ello se adaptan los modelos de componentes intentando minimizar los conflictos que aparecen al integrar tiempo real y comportamiento dinámico y conseguir reemplazos de componentes en un tiempo acotado. Uno de los principales retos para esto es el cálculo de los tiempos requeridos por las diferentes operaciones necesarias para realizar un reemplazo de componente. El otro gran obstáculo es conocer los tiempos de operación de los componentes del sistema cuando la implementación de éstos puede cambiar durante la vida del sistema. En este trabajo se describe la implementación de un marco de componentes que aporta una solución parcial a estos problemas. Se proporciona un modelo de componentes junto con sus correspondientes algoritmos para asegurar que los componentes pueden ser cargados y reemplazados en tiempo de ejecución sin interferir en el cumplimiento de sus plazos de ejecución. El modelo está diseñado para evitar fallos en los reemplazos de componente. Finalmente se aporta la validación de los conceptos presentados.Cano, J.; García Valls, M.; Basanta Val, P. (2014). Marco de Componentes con soporte para reemplazo dinámico y seguro en sistemas de tiempo real. 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IEEE Transactions on Industrial Informatics, 9(1), 228-236. doi:10.1109/tii.2012.2198662García-Valls, M., Basanta-Val, P., 2013a. A real-time perspective of service composition: Key concepts and some contributions. Journal of Systems Architecture. Elsevier, http://dx.doi.org/10.1016/j.sysarc.2013.06.008.García-Valls, M., Basanta-Val, P., Marcos, M., Estévez, E., 2013b. A bi- dimensional QoS model for SOA and real-time middleware. International Journal of Computer Systems Science and Engineering, CLR Publishing,ISSN 0267-6192(To appear).Kramer, J., & Magee, J. (1990). The evolving philosophers problem: dynamic change management. IEEE Transactions on Software Engineering, 16(11), 1293-1306. doi:10.1109/32.60317Li, W. (2012). QoS Assurance for Dynamic Reconfiguration of Component-Based Software Systems. IEEE Transactions on Software Engineering, 38(3), 658-676. doi:10.1109/tse.2011.37McKinley, P. K., Sadjadi, S. M., Kasten, E. P., & Cheng, B. H. C. (2004). Composing adaptive software. 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