"InstantSocial" – Implementing a Distributed Mobile Multi-user Application with Adaptation Middleware

In this position paper we explore how new capabilites of mobile devices could be used to setup distributed multi-user mobile applications with potentially high interest for end users. We describe an example of such an application by transposing Internet social network trends and principles to a mobile ad hoc environment. Then we present a tentative design and implentation sketch of this application in terms of the MUSIC context-aware adaptation middleware we are currently developing

Ubiquitous Information Systems (UBIS): A design research study of intelligent middleware and architecture

Ubiquitous information systems (UBIS) adapt current Information System thinking to explicitly differentiate technology between hardware devices and software components in relation to people and process. More recent ubiquitous computing approaches provide the means to link Web content and services to a number of mobile devices (evolving from earlier Palm Computers to more recent smart phones and ambient screens), adapting information to provide mobile business solutions. In general, these approaches focus on providing the means to improve specific information access and transcoding but not on how the information can be discovered and accessed on-the-fly. This paper explores how a number of investment banking systems can be re-used to provide the invisibility of pervasive access and uncover more effective architectural models for strategies of this type. A proof-of-concept intelligent middleware Web service is built to further test and explore how human-devices-application connections can be made sporadically and not limited to pre-configured access to specific applications and data

Design process enabling adaptation in pervasive heterogeneous contexts

International audienceIn the next decades, the growth in population ageing will cause important problems to most industrialized countries. To tackle this issue, Ambient Assistive Living (AAL) systems can reinforce the well-being of elderly people, by providing emergency, autonomy enhancement, and comfort services. These services will postpone the need of a medicalized environment, and will allow the elderly to stay longer at home. However, each elderly has specific needs and a deployment environment of such services is likely unique. Furthermore, the needs evolve over time, and so does the deployment environment of the system. In this paper, we propose the use of a model-based development method, the adaptive medium approach, to enable dynamic adaptation of AAL systems. We also propose improvements to make it more suited to the AAL domain, such as considering heterogeneity and a composition model. The paper includes an evaluation of the prototype implementing the approach, and a comparison with related work

MEDUSA: Middleware for End-User Composition of Ubiquitous Applications

International audienceActivity-oriented computing (AOC) is a paradigm promoting the run-time realization of applications by composing ubiquitous services in the user's surroundings according to abstract specifications of user activities. The paradigm is particularly well-suited for enacting ubiquitous applications. However, there is still a need for end-users to create and control the ubiquitous applications because they are better aware of their own needs and activities than any existing context-aware system could ever be. In this chapter, we give an overview of state of the art ubiquitous application composition, present the architecture of the MEDUSA middleware and demonstrate its realization, which is based on existing open-source solutions. On the basis of our discussion on state of the art ubiquitous application composition, we argue that current implementations of the AOC paradigm are lacking in end-user support. Our solution, the MEDUSA middleware, allows end-users to explicitly compose applications from networked services, while building on an activity-oriented computing infrastructure to dynamically realize the composition

Toward the adaptation of component-based architectures by model transformation: behind smart user interfaces

Graphical user interfaces are not always developed for remaining static. There are GUIs with the need of implementing some variability mechanisms. Component-based GUIs are an ideal target for incorporating this kind of operations, because they can adapt their functionality at run-time when their structure is updated by adding or removing components or by modifying the relationships between them. Mashup user interfaces are a good example of this type of GUI, and they allow to combine services through the assembly of graphical components. We intend to adapt component based user interfaces for obtaining smart user interfaces. With this goal, our proposal attempts to adapt abstract component-based architectures by using model transformation. Our aim is to generate at run-time a dynamic model transformation, because the rules describing their behavior are not pre set but are selected from a repository depending on the context. The proposal describes an adaptation schema based on model transformation providing a solution to this dynamic transformation. Context information is processed to select at run-time a rule subset from a repository. Selected rules are used to generate, through a higher-order transformation, the dynamic model transformation. This approach has been tested through a case study which applies different repositories to the same architecture and context. Moreover, a web tool has been developed for validation and demonstration of its applicability. The novelty of our proposal arises from the adaptation schema that creates a non pre-set transformation, which enables the dynamic adaptation of component-based architectures

Composing Components and Services Using a Planning-Based Adaptation Middleware

Self-adaptive component-based architectures provide methods and mechanisms to support the dynamic adaptation of their structure under evolving execution context. Dynamic adaptation is particularly relevant in the domain of ubiquitous computing, which is subject to numerous unexpected changes of the execution context. In this paper, we focus on changes in the service provider landscape: business services may dynamically come and go, and their quality of service may vary. We introduce an extension of the MADAM component-based planning framework that optimizes the overall utility of applications when such changes occur. MADAM planning is based on dynamic configuration of component frameworks. The extended planning framework supports seamless configuration of component frameworks based on both local and remote components and services. In particular, components and services can be plugged in interchangeably to provide functionalities defined by the component framework. The extended planning framework is illustrated and validated on a use case scenario

Contributions to the safe execution of dynamic component-based real-time systems

Traditionally, real-time systems have based their design and execution on barely dynamic models to ensure, since design time, the temporal guarantees in the execution of their functionality. Great effort is being applied nowadays to progressively develop more dynamic systems, with the target of changing during their execution and to adapt themselves to their environment. The capability to change and to reconfigure themselves represents remarkable advantages as the capability to fix errors and to add new functionality with on-line updates. This means to be able to be updated without needing to stop the service, that may imply monetary losses in many cases. Design and development techniques based on components have become popular due to the use of components, which allows simplifying the system design, code reusability and updates through the substitution of components. The target of this thesis work is to provide certain degree of dynamism to real-time systems allowing them to replace components, incorporating new functionality of fixing existing bugs. On that purpose, a component-based framework is proposed, as well as the corresponding task in charge of providing dynamism to the system. The main contribution is to provide a framework to allow safe component replacements. Safe meaning that incorrect executions of tasks are avoided even y multiple tasks are executing concurrently and making use of the same data. Also that temporal guarantees are provided for every task. This framework incorporates a generic component model with real-time threads, a components replacement model with execution times that are known and bounded, and different strategies to apply such component replacement model. Some mechanisms to maintain a seamless and safe execution, regarding concurrency, before, during, and after applying the processes in charge of replacing running components are also described. Seamless execution means that components themselves do not perform the replacements, and safe means that temporal guarantees are provided and components are not affected in their execution. Part of these mechanisms are the system schedulability analysis and the framework tasks as well as reserving the needed resources for such scheduling to be correct. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Los sistemas de tiempo real han basado tradicionalmente su desarrollo en modelos altamente predecibles ya que estos requieren garantías temporales en su ejecución. A lo largo de los años, la technología de tiempo real ha ido penetrando en diferentes campos de aplicación y ajustándose a paradigmas de desarrollo software más novedosos. Esto ha presentado y presenta en la actualidad un tremendo reto ya que estas aplicaciones suelen tener un alto grado de dinamismo, lo que entra en conflicto con la predictibilidad temporal y, en general la ejecución segura de los mismos. Hoy en dia se esta realizando un gran esfuerzo en el desarrollo de sistemas cada vez más dinamicos que permitan adaptar su estructura en tiempo de ejecución para adaptarse a entornos que presentan condiciones cambiantes. La capacidad de soportar este tipo de dinamismo presenta ventajas descatables como permitir corregir fallos y anadir funcionalidad mediante actualizaciones en caliente, es decir, poder actualizarse sin necesidad de realizar paradas en su servicio, lo que podria implicar costes monetarios en muchos casos o perdidas temporales de servicio. Por otro lado, las técnicas de diseño y desarrollo basadas en componentes se han hecho muy populares y su aplicación a los sistemas de tiempo real gana terreno día a día. Uno de los principales motivos de ellos es que el uso de componentes permite simplificar el diseño del sistema, la reutilizacion de codigo e incluso la actualizacion del mismo mediante la substitucion de componentes. En esta tesis se aborda el objetivo de proveer a los sistemas de tiempo real de cierto grado de dinamismo para poder reemplazar componentes de forma segura, que permita incorporar nuevas funcionalidades o corregir errores existentes. Para ello, en esta tesis se ha elaborado de un marco de trabajo para dar soporte a reemplazos de componentes de forma segura, entendiendo como tal que el hecho de que no se produzcan ejecuciones incorrectas debido a la ejecución concurrente de multiples tareas, asi como el garantizar los tiempos de ejecucion de cada tarea y acotar la duración temporal de los reemplazos. El marco de trabajo propuesto está basado, pues, en componentes de tiempo real, que tiene en cuenta los requisitos temporales en la ejecución de los componentes del sistema y de las tareas propias del marco que dan soporte a estos mecanismos de reemplazo. Este marco de trabajo incorpora un modelo generico de componente con tareas de tiempo real, un modelo de reemplazo de componentes cuyos tiempos de ejecucion son conocidos y limitados en tiempo y diferentes estrategias de aplicacion de dicho modelo de reemplazo de componente. Las contribuciones propuestas integran el analisis de la planificabilidad de los componentes del sistema y de las tareas del marco de componentes para permitir establecer los parámetros de reserva de los recursos necesarios para las tareas del marco. Por último, se realiza una validación empírica en la que se comprueba experimentalmente la validez del modelo tanto de forma genérica como en un escenario específico y determinando también los recursos necesarios para su implementación

How To Touch a Running System

The increasing importance of distributed and decentralized software architectures entails more and more attention for adaptive software. Obtaining adaptiveness, however, is a difficult task as the software design needs to foresee and cope with a variety of situations. Using reconfiguration of components facilitates this task, as the adaptivity is conducted on an architecture level instead of directly in the code. This results in a separation of concerns; the appropriate reconfiguration can be devised on a coarse level, while the implementation of the components can remain largely unaware of reconfiguration scenarios. We study reconfiguration in component frameworks based on formal theory. We first discuss programming with components, exemplified with the development of the cmc model checker. This highly efficient model checker is made of C++ components and serves as an example for component-based software development practice in general, and also provides insights into the principles of adaptivity. However, the component model focuses on high performance and is not geared towards using the structuring principle of components for controlled reconfiguration. We thus complement this highly optimized model by a message passing-based component model which takes reconfigurability to be its central principle. Supporting reconfiguration in a framework is about alleviating the programmer from caring about the peculiarities as much as possible. We utilize the formal description of the component model to provide an algorithm for reconfiguration that retains as much flexibility as possible, while avoiding most problems that arise due to concurrency. This algorithm is embedded in a general four-stage adaptivity model inspired by physical control loops. The reconfiguration is devised to work with stateful components, retaining their data and unprocessed messages. Reconfiguration plans, which are provided with a formal semantics, form the input of the reconfiguration algorithm. We show that the algorithm achieves perceived atomicity of the reconfiguration process for an important class of plans, i.e., the whole process of reconfiguration is perceived as one atomic step, while minimizing the use of blocking of components. We illustrate the applicability of our approach to reconfiguration by providing several examples like fault-tolerance and automated resource control

Dienstekomposition in intelligenten Umgebungen basierend auf KI-Planung

In intelligenten Umgebungen wird das Zusammenspiel mehrerer Dienste benötigt, welches durch eine Dienstekomposition erzielt werden kann. KIPlanung ist eine Methode, dies umzusetzen. Im Rahmen der vorliegenden Arbeit wurde experimentell das Laufzeitverhalten von verschiedenen Planern untersucht. Daneben wurden die Möglichkeiten der Modellierung von Problemen der Dienstekomposition evaluiert, was zu einer Richtline für die verteilte Modellierung von Dienstbeschreibungen führte. Basierend auf den Erfahrungen wurde ein Composer entworfen und umgesetzt, der verschiedene Planer nutzen kann