Avances en sistemas software para robótica con atributos de calidad de servicio adaptativos

En esta Tesis se presenta Nerve, un middleware para sistemas distribuidos y robótica basado en la librería de comunicaciones multiplataforma ACE y el en estándar the Data Distribution Service (DDS). Nerve garantiza la escalabilidad y las calidades de servico (QoS) necesarias para sistemas de tiempo real, pero también permite a los desarrolladores reutilizar la mayoría del código existente y ofrecerles los mecanismos necesarios para desplegar partes de dicho código en tareas distribuidas. Además, Nerve ofrece una infraestructura de monitorización y adaptación. La infraestructura de monitorización permite tener acceso a las métricas del sistema (CPU, memoria, etc.) y a las métricas de usuario (QoS, variables utilizadas en algoritmos, etc.). Para ello se describe un mecanismo de instrumentación automática de código utilizando las herramientas basadas en los compiladores LLVM. Con respecto a la infraestructura de adaptación, ésta se encarga de modificar las QoS para obtener el mejor comportamiento posible del robot con los recursos disponibles en tiempo de ejecución. También se describen la implementación e integración en Nerve de un mecanismo de comunicaciones basado en petición/respuesta que, junto al original basado en la publicación/suscripción, permite dar soporte al modelo cliente/servidor. Este modelo clásico de comunicaciones se ha utilizado con éxito para integrar Nerve en otros frameworks existentes para robótica. Finalmente, los beneficios del uso de Nerve se verán reflejados a través de su aplicación en sistemas robóticos reales.Los robots sociales son robots autónomos que trabajan en entornos sociales reales donde tienen que interactuar con seres humanos e incluso con otros robots. La implementación de estos sistemas robóticos está moviendose hacia el uso de frameworks basados en componentes, los cuales se centran en la reusabilidad y en la evolución del software. De esta manera, el software de un robot está compuesto por entidades binarias (componentes) distribuidos que se comunican entre sí utilizando un middleware de comunicaciones, que permite abstraer al desarrollador de los detalles de bajo nivel y comunicar sistemas heterogéneos. Si embargo, el uso de estos frameworks basados en componentes y middleware para robótica implica una curva de aprendizaje muy pronunciada, además de introducir nuevos desafíos a los desarrolladores para poder satisfacer los requisitos de alto rendimiento y otras calidades de servicio. El análisis y la verificación de esas propiedades no funcionales debe incluir formas de monitorizar los diferentes valores del sistema. Normalmente, las herramientas de monitorización para robótica incluyen sólo información sobre el estado de los componentes y la acción típica a realizar, en caso de detectar que no se satisface algún requisito, es parar el software, lo que suele implicar parar el robot. Obviamente, este escenario no es la mejor opción para los robots sociales, a menos que introduzcamos un mecanismo que garantice que el sistema de control del robot se autoadaptará y reparará él mismo si es necesario (y posible). De esta forma, aparece un nuevo requisito: un sistema de control de un robot debe de ser tolerante a fallos, permitiendo auto-adaptarse, es decir: detectar cambios significativos, decidir cómo reaccionar, y actuar para ejecutar tales decisiones

A quality of service based framework for dynamic, dependable systems

There is currently much UK government and industry interest towards the integration of complex computer-based systems, including those in the military domain. These systems can include both mission critical and safety critical applications, and therefore require the dependable communication of data. Current modular military systems requiring such performance guarantees are mostly based on parameters and system states fixed during design time, thus allowing a predictable estimate of performance. These systems can exhibit a limited degree of reconfiguration, but this is typically within the constraints of a predefined set of configurations. The ability to reconfigure systems more dynamically, could lead to further increased flexibility and adaptability, resulting in the better use of existing assets. Current software architecture models that are capable of providing this flexibility, however, tend to lack support for dependable performance. This thesis explores the benefits for the dependability of future dynamic systems, built on a publish/subscribe model, from using Quality of Service (QoS) methods to map application level data communication requirements to available network resources. Through this, original contributions to knowledge are created, including; the proposal of a QoS framework that specifies a way of defining flexible levels of QoS characteristics and their use in the negotiation of network resources, a simulation based evaluation of the QoS framework and specifically the choice of negotiation algorithm used, and a test-bed based feasibility study. Simulation experimentation conducted comparing different methods of QoS negotiation gives a clear indication that the use of the proposed QoS framework and flexible negotiation algorithm can provide a benefit in terms of system utility, resource utilisation, and system stability. The choice of negotiation algorithm has a particularly strong impact on these system properties. The cost of these benefits comes in terms of the processing power and execution time required to reach a decision on the acceptance of a subscriber. It is suggested, given this cost, that when computational resources are limited, a simpler priority based negotiation algorithm should be used. Where system resources are more abundant, however, the flexible negotiation algorithm proposed within the QoS framework can offer further benefits. Through the implementation of the QoS framework within an existing military avionics software architecture based emulator on a test-bed, both the technical challenges that will need to be overcome and, more importantly, the potential viability for the inclusion of the QoS framework have been demonstrated

Middleware Technologies for Cloud of Things - a survey

The next wave of communication and applications rely on the new services provided by Internet of Things which is becoming an important aspect in human and machines future. The IoT services are a key solution for providing smart environments in homes, buildings and cities. In the era of a massive number of connected things and objects with a high grow rate, several challenges have been raised such as management, aggregation and storage for big produced data. In order to tackle some of these issues, cloud computing emerged to IoT as Cloud of Things (CoT) which provides virtually unlimited cloud services to enhance the large scale IoT platforms. There are several factors to be considered in design and implementation of a CoT platform. One of the most important and challenging problems is the heterogeneity of different objects. This problem can be addressed by deploying suitable "Middleware". Middleware sits between things and applications that make a reliable platform for communication among things with different interfaces, operating systems, and architectures. The main aim of this paper is to study the middleware technologies for CoT. Toward this end, we first present the main features and characteristics of middlewares. Next we study different architecture styles and service domains. Then we presents several middlewares that are suitable for CoT based platforms and lastly a list of current challenges and issues in design of CoT based middlewares is discussed.Comment: http://www.sciencedirect.com/science/article/pii/S2352864817301268, Digital Communications and Networks, Elsevier (2017

Middleware Technologies for Cloud of Things - a survey

The next wave of communication and applications rely on the new services provided by Internet of Things which is becoming an important aspect in human and machines future. The IoT services are a key solution for providing smart environments in homes, buildings and cities. In the era of a massive number of connected things and objects with a high grow rate, several challenges have been raised such as management, aggregation and storage for big produced data. In order to tackle some of these issues, cloud computing emerged to IoT as Cloud of Things (CoT) which provides virtually unlimited cloud services to enhance the large scale IoT platforms. There are several factors to be considered in design and implementation of a CoT platform. One of the most important and challenging problems is the heterogeneity of different objects. This problem can be addressed by deploying suitable "Middleware". Middleware sits between things and applications that make a reliable platform for communication among things with different interfaces, operating systems, and architectures. The main aim of this paper is to study the middleware technologies for CoT. Toward this end, we first present the main features and characteristics of middlewares. Next we study different architecture styles and service domains. Then we presents several middlewares that are suitable for CoT based platforms and lastly a list of current challenges and issues in design of CoT based middlewares is discussed.Comment: http://www.sciencedirect.com/science/article/pii/S2352864817301268, Digital Communications and Networks, Elsevier (2017

Distributed sensor architecture for intelligent control that supports quality of control and quality of service

This paper is part of a study of intelligent architectures for distributed control and communications systems. The study focuses on optimizing control systems by evaluating the performance of middleware through quality of service (QoS) parameters and the optimization of control using Quality of Control (QoC) parameters. The main aim of this work is to study, design, develop, and evaluate a distributed control architecture based on the Data-Distribution Service for Real-Time Systems (DDS) communication standard as proposed by the Object Management Group (OMG). As a result of the study, an architecture called Frame-Sensor-Adapter to Control (FSACtrl) has been developed. FSACtrl provides a model to implement an intelligent distributed Event-Based Control (EBC) system with support to measure QoS and QoC parameters. The novelty consists of using, simultaneously, the measured QoS and QoC parameters to make decisions about the control action with a new method called Event Based Quality Integral Cycle. To validate the architecture, the first five Braitenberg vehicles have been implemented using the FSACtrl architecture. The experimental outcomes, demonstrate the convenience of using jointly QoS and QoC parameters in distributed control systems.The study described in this paper is a part of the coordinated project COBAMI: Mission-based Hierarchical Control. Education and Science Department Spanish Government. CICYT: MICINN: DPI2011-28507-C02-01/02 and project "Real time distributed control systems" of the Support Program for Research and Development 2012 UPV (PAID-06-12).Poza-Lujan, J.; Posadas-Yagüe, J.; Simó Ten, JE.; Simarro Fernández, R.; Benet Gilabert, G. (2015). Distributed sensor architecture for intelligent control that supports quality of control and quality of service. Sensors. 15(3):4700-4733. https://doi.org/10.3390/s150304700S4700473315

The SATIN component system - a metamodel for engineering adaptable mobile systems

Mobile computing devices, such as personal digital assistants and mobile phones, are becoming increasingly popular, smaller, and more capable. We argue that mobile systems should be able to adapt to changing requirements and execution environments. Adaptation requires the ability-to reconfigure the deployed code base on a mobile device. Such reconfiguration is considerably simplified if mobile applications are component-oriented rather than monolithic blocks of code. We present the SATIN (system adaptation targeting integrated networks) component metamodel, a lightweight local component metamodel that offers the flexible use of logical mobility primitives to reconfigure the software system by dynamically transferring code. The metamodel is implemented in the SATIN middleware system, a component-based mobile computing middleware that uses the mobility primitives defined in the metamodel to reconfigure both itself and applications that it hosts. We demonstrate the suitability of SATIN in terms of lightweightedness, flexibility, and reusability for the creation of adaptable mobile systems by using it to implement, port, and evaluate a number of existing and new applications, including an active network platform developed for satellite communication at the European space agency. These applications exhibit different aspects of adaptation and demonstrate the flexibility of the approach and the advantages gaine