Rui S. Moreira

Reflection, self-awareness and self-healing in OpenORB

There is a growing interest in the area of self-healing systems. Self-healing does however impose considerable demands on system infrastructures---especially in terms of openness and support for reconfigurability. This paper proposes that the self-awareness inherent in reflective technologies lends itself well to the construction of self-healing systems. In particular, the paper examines the support provided by the Open ORB reflective middleware technology for the construction of this increasingly important class of system.

Supporting adaptable distributed systems with FORMAware

The interactive and ubiquitous nature of future distributed services (e.g. digital libraries, learning systems, etc.) makes them more architectural and resource demanding. Consequently, next generation middleware frameworks should support both shorter and longer-term adaptation (i.e. a priori and a posteriori reconfiguration). In fact, current component standards [W. Emmerich, (2000)] leverage software reusability and diminish development costs. Nevertheless, it is also a fact that existing middleware, which succeeded in meeting the goals of heterogeneity and interoperability, is not open enough for tackling the problem of dynamic evolution. We present FORMAware, a framework that combines a novel component-based programming model enhanced by a reflective design, the former capturing the knowledge about software architecture abstractions (e.g. components, connectors, style managers, style rules) while the latter offering architecture awareness by explicitly opening the content and structure of both atomic and composite components (via introspection and adaptation meta-objects). In addition, FORMAware provides a set of tools and services for automating software development and adaptation (i.e. support for the generation, assembly, deployment and dynamic reconfiguration processes).

Dynamic adaptation of personal ubicomp environments

A significant challenge for personal and ubiquitous computing is to cope with frequent changes of user preferences, profile, location, and context in general. In this special issue we bring you an update on how dynamic adaptation is being used to address this challenge. Dynamic adaptation provides runtime modeling and monitoring of both structural and behavioral aspects, possibly at different levels of the open systems interconnection (OSI) model. We are thinking in particular of personal and ubiquitous computing environments assembled from a variety of custom-of-theshelf (COTS) systems that are planned to work independently of each other. Dynamic adaptation opens the door to reason about and undertake policies and strategies without compromising the functionality and integration of COTS systems in the environment. The papers in this special issue cover different aspects of dynamic adaptation in PUC.

Communal Network Architecture for Sharing High Bandwidth Services

This paper presents a network architecture for provisioning communal Internet access services to residential customers. The advantages of adopting the proposed architecture are enumerated both for Internet Service Providers (ISP) and residential clients. The paper presents also the CommGate, a gateway specially developed for managing the network traffic through multiple communal accesses, . Tests were carried out simulating several community scenarios with different number of customers and generating different traffic loads. The results allow us to conclude about the performance of the CommGate and the benefits of the proposed architecture.

FORMAware: framework of reflective components for managing architecture adaptation

Software engineers use abstraction to better understand, model and reason about the surrounding world. Recently Architecture Description Languages (ADLs) introduced new levels of abstraction with potential use at run-time to support system evolution. In this paper we propose the FORMAware architecture that blends run-time architectural representation with a reflective programming model to address adaptation issues and promote the proximity between design and development. Reflection opens up composition architecture through a replaceable default style manager that permits to execute architecture reconfigurations. This manager enforces the structural integrity of the architecture through a set of style rules that developers may change to meet other architectural strategies. Each reconfiguration runs in the scope of a transaction that we may commit or rollback.

A behavioral reflective architecture for managing the integration of personal ubicomp systems: automatic SNMP-based discovery and management of behavior context in smart-spaces

AbstractContext-aware ubiquitous computing systems should be able to introspect the surrounding environment and adapt their behavior according to other existing systems and context changes. Although numerous ubiquitous computing systems have been developed that are aware of different types of context such as location, social situation, and available computational resources, few are aware of their computational behavior. Computational behavior introspection is common in reflective systems and can be used to improve the awareness and autonomy of ubicomp systems. In this paper, we propose a decentralized approach based on Simple Network Management Protocol (SNMP) and Universal Plug and Play (UPnP), and on state transition models to model and expose computational behavior. Typically, SNMP and UPnP are targeted to retrieve raw operational variables from managed network devices and consumer electronic devices, e.g., checking network interface bandwidth and automating device discovery and plug and play operations. We extend the use of these protocols by exposing the state of different ubicomp systems and associated state transitions statistics. This computational behavior may be collected locally or remotely from ubicomp systems that share a physical environment, and sent to a coordinator node or simply shared among ubicomp systems. We describe the implementation of this behavior awareness approach in a home health-care environment equipped with a VoIP Phone and a drug dispenser. We provide the means for exposing and using the behavior context in managing a simple home health-care setting. Our approach relies on a system state specification being provided by manufacturers. In the case where the specification is not provided, we show how it can be automatically discovered. We propose two machine learning approaches for automatic behavior discovery and evaluate them by determining the expected state graphs of our two systems (a VoIP Phone and a drug dispenser). These two approaches are also evaluated regarding the effectiveness of generated behavior graphs.

A network approach for communal access services

The residential networking market is evolving and new operating paradigms are emerging. The ubiquitous use of Small Office/Home Office (SOHO) networks is increasing the demands on SOHO routers. These economical network elements, however, are too simple to deal with the high demands of their users, especially in residential settings where P2P, video and VoIP traffic is becoming predominant. This paper presents a communal gateway - CommGate - that enables individuals in a building to share multiple communal Internet links and service facilities. The paper presents also some tests simulating several user communities with different number of customers characterized by different profiles (cf. Gold, Silver and Bronze) and generating different traffic loads. These tests illustrate the benefits of using the CommGate and the usefulness of the proposed communal architecture.