Nelson Matthys

LooCI: a loosely-coupled component infrastructure for networked embedded systems

Considerable research has been performed in applying run-time reconfigurable component models to the domain of wireless sensor networks. The ability to dynamically deploy and reconfigure software components has clear advantages in sensor network deployments, which are typically large in scale and expected to operate for long periods in the face of node mobility, dynamic environmental conditions and changing application requirements. To date, research on component and binding models for sensor networks has primarily focused on the development of specialized component models that are optimized for use in resource-constrained environments. However, current approaches impose significant overhead upon developers and tend to use inflexible binding models based on remote procedure calls. To address these concerns, we introduce a novel component and binding model for networked embedded systems (LooCI). LooCI components are designed to impose minimal additional overhead on developers. Furthermore, LooCI components use a novel event-based binding model that allows developers to model rich component interactions, while providing support for easy interception, re-wiring and re-use. A prototype implementation of our component and binding model has been realised for the SunSPOT platform. Our preliminary evaluation shows that LooCI has an acceptable memory footprint and imposes minimal overhead on developers.

LooCI: The Loosely-coupled Component Infrastructure

Creating and managing applications for Wireless Sensor Networks (WSNs) is complicated by large scale, resource constraints and network dynamics. Reconfigurable component models minimize these complexities throughout the application lifecycle. However, contemporary component based middleware for WSNs is limited by its poor support for distribution. This paper introduces the Loosely-coupled Component Infrastructure (LooCI), a middleware for building distributed component-based WSN applications. LooCI advances the state-of-the-art by cleanly separating distributed concerns from component implementation, supporting application-level interoperability between heterogeneous WSN platforms and providing compatibility testing of bindings at runtime. Together, these features promote the safe and efficient composition and reconfiguration of distributed WSN applications. We evaluate the performance of LooCI on three classes of sensor nodes and demonstrate that these features can be provided with minimal overhead in terms of computation, memory and message passing.

A middleware platform to support river monitoring using wireless sensor networks

Flooding is a critical global problem, which is growing more severe due to the effects of climate change. This problem is particularly acute in the state of São Paulo, Brazil, where flooding during the rainy season incurs significant financial and human costs. Another critical problem associated with flooding is the high level of pollution present in urban rivers. Efforts to address these problems focus upon three key research areas: river monitoring, modelling of river conditions and incident response. This paper introduces a rich next-generation middleware platform designed to support wireless sensor network based environmental monitoring along with a supporting hardware platform. This system has been deployed and evaluated in a real-world river monitoring scenario in the city of São Carlos, Brazil.

Building Wireless Sensor Network Applications with LooCI

Considerable research has been performed in applying run-time reconfigurable component models to the domain of wireless sensor networks. The ability to dynamically deploy and reconfigure software components has clear advantages in sensor networks, which are typically large in scale and expected to operate for long periods in the face of node mobility, dynamic environmental conditions, and changing application requirements. LooCI is a component and binding model that is optimized for use in resource-constrained environments such as Wireless Sensor Networks. LooCI components use a novel event-based binding model that allows developers to model rich component interactions, while providing support for run-time reconfiguration, reflection, and policy-based management. This paper reports on the design of LooCI and describes a prototype implementation for the Sun SPOT. This platform is then evaluated in context of a real-world river monitoring and warning scenario in the city of Sao Carlos, Brazil.

μ PnP: plug and play peripherals for the internet of things

Internet of Things (IoT) applications require diverse sensors and actuators. However, contemporary IoT devices provide limited support for the integration of third-party peripherals. To tackle this problem, we introduce μPnP: a hardware and software solution for plug-and-play integration of embedded peripherals with IoT devices. μPnP provides support for: driver development, automatic integration of third-party peripherals, discovery and remote access to peripheral services. This is achieved through a low-cost hardware identification approach, a lightweight driver language and a multicast network architecture. Evaluation shows that μPnP has a minimal memory footprint, reduces development effort and provides true plug-and-play integration at orders of magnitude less energy than USB.

Applying a Multi-paradigm Approach to Implementing Wireless Sensor Network Based River Monitoring

This paper describes the application of the DisSeNT middleware to implement Wireless Sensor Network based river monitoring. DisSeNT provides LooCI, an efficient run-time reconfigurable component model, PMA, a lightweight policy-based management framework and QARI, a declarative quality-aware deployment framework. Using a river monitoring case-study, this paper analyses how these distinct software development paradigms can be used in a complimentary fashion to develop efficient wireless sensor network applications. The resulting system has been deployed and evaluated in a real-world river monitoring scenario in the city of São Carlos, Brazil.

Energy aware software evolution for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are subject to high levels of dynamism arising from changing environmental conditions and application requirements. Reconfiguration allows software functionality to be optimized for current environmental conditions and supports software evolution to meet variable application requirements. Contemporary software modularization approaches for WSNs allow for software evolution at various granularities; from monolithic re-flashing of OS and application functionality, through replacement of complete applications, to the reconfiguration of individual software components. As the nodes that compose a WSN must typically operate for long periods on a single battery charge, estimating the energy cost of software evolution is critical. This paper contributes a generic model for calculating the energy cost of the reconfiguration in WSN. We have embedded this model in the LooCI middleware, resulting in the first energy aware reconfigurable component model for sensor networks. We evaluate our approach using two real-world WSN applications and find that (i.) our model accurately predicts the energy cost of reconfiguration and (ii.) component-based reconfiguration has a high initial cost, but provides energy savings during software evolution.

Policy-Driven Tailoring of Sensor Networks

The emerging reality of wireless sensor networks deployed as long-lived infrastructure mandates an approach to tailor developed artefacts at run-time to avoid costly reprogramming. Support for dynamic concerns, such as adaptation, calibration or tuning of the functional and non-functional behaviour by application users and infrastructure managers raises the need for fine-grained run-time customization. This paper presents a policy-based paradigm to realize the diverse concerns of the involved actors by enabling fine-tuning and optimization of the run-time environment. Integration of the policy paradigm into various main programming models is analyzed. A prototype implementation of the paradigm in the context of an event-component based wireless sensor network platform is evaluated on the SunSPOT sensor platform.

A Component and Policy-Based Approach for Efficient Sensor Network Reconfiguration

Contemporary wireless sensor network deployments are long-lived, large scale and resource constrained. Longevity demands mechanisms that support reconfiguration to meet changing application requirements, large scale demands high-level abstractions to support network management and stringent resource constraints necessitate a high degree of efficiency in middleware to support application development and management. This paper presents the Component and Policy Infrastructure (CaPI), a middleware providing two complementary abstractions for contemporary sensor network development and management. A reconfigurable component model supports embedded developers during initial application development and enables management of evolving functional requirements, while an expressive policy language supports the specification and management of behavioural concerns by administrators or domain experts. CaPI provides a clear decoupling between application logic and behaviour, enabling efficient customization and dynamic reconfiguration of application functionality and behaviour.

On the integration of sensor networks and general purpose IT infrastructure

Integrating sensor networks with general purpose IT infrastructure has been confirmed as a complex problem in the development and management of industrial sensor applications. This integration is complex because a single general purpose application queries multiple sensor networks and a single sensor network has to serve multiple applications. This paper identifies three challenges that need to be addressed by middleware in order to enable this integration: federated management, interoperability and adaptability across the whole infrastructure. The paper presents a taxonomy of middleware solutions and positions the identified challenges in a survey of state-of-the-art middleware research we conducted earlier. By looking at sensor network middleware from an application (business) perspective, we come to the conclusion that time may have come to consolidate middleware efforts presented during the past years.