Stefano Bocchino

Middleware solutions in WSN: The IoT oriented approach in the ICSI project

A large number of middleware solutions targeted to wireless sensor networks have been deployed during the years with the aim of bridging the gap between the high level requirements of the applications and the low level hardware complexity. In the paper, a review of state-of-the-art middleware platforms is first presented by highlighting basic design principles and network protocol solutions for next generation middleware targeted to the Internet of Things (IoT) scenario. Then, the general architecture of the middleware to be instantiated within the European project Intelligent Cooperative Sensing for Improved traffic efficiency (ICSI) is presented by detailing its architecture and IoT enabling solutions. The ICSI WSN middleware introduces state-of-the-art advances in IoT middleware design by merging a publish/subscribe model with a virtual machine based design.

PyFUNS: A Python Framework for Ubiquitous Networked Sensors

In recent years Wireless Sensor Networks (WSNs) have been deployed in wide range of applications from the health and environment monitoring to building and industrial control. However, the pace of prevalence of WSN is slower than anticipated by the research community due to several reasons including required embedded systems expertise for developing and deploying WSNs; use of proprietary protocols; and limits in scalability and reliability. In this paper we propose PyFUNS (Python-based Framework for Ubiquitous Networked Sensors) to address these challenges. PyFUNS handles low level and networking functionalities, using the services provided by Contiki, and leaves to the user only the task of application development in the form of Python scripts. This approach reduces required expertise in embedded systems to develop WSN based applications. PyFUNS also uses 6LoWPAN and CoAP standard protocols to enable interoperability and ease of integration with other systems, pursuing the Internet of Things vision. Through a real implementation of PyFUNS in two constrained platforms we proved its feasibility in mote devices, as well as its performance in terms of control delay, energy consumption and network traffic in several network topologies. As it is possible with PyFUNS to easily compare performance of different deployments of distributed application, PyFUNS can be used to identify optimal design of distributed application.

Video streaming applications in wireless camera networks: A change detection based approach targeted to 6LoWPAN

Video streaming applications in wireless camera networks composed by low-end devices are attractive for enabling new pervasive high value services. When complying with the 6LoWPAN standard, the reduced amount of available bandwidth imposes the transmission of low resolution images. In this paper we present a low-complexity algorithm based on background subtraction and error resilience techniques aimed at reducing the transmission bandwidth of a video stream of uncompressed images thus permitting a higher frame rate. By means of realistic simulation studies, the performance of the presented algorithm is analyzed against state-of-the-art solutions like JPEG. These results can be considered for designing a next generation of smart cameras suited for 6LoWPAN.

PyoT, a macroprogramming framework for the Internet of Things

The extensive diffusion of new generation wireless sensor networks requires the adoption of flexible mechanisms capable of abstracting the functionality of the nodes, facilitating their integration in larger computing infrastructures. This paper presents PyoT, a framework designed to simplify the development of complex applications for the Internet of Things, coordinating the activities of group of nodes. Adopting the macroprogramming paradigm, PyoT lets programmers focus on the application goal, hiding low-level communication details. The framework is capable of efficiently distributing the processing effort inside the network, providing support for “in-network” processing applications. The proposed system is evaluated both in an emulated scenario and on a real testbed.

SPEED routing protocol in 6LoWPAN networks

The integration of the Wireless Sensor Networks (WSNs) technology in the Internet world is one of the biggest challenges to enable the Internet of Things (IoT) vision. In order to really benefit of such kind of integration the IPv6 addressing method and communication protocols adopted in the IoT must be modified to match the WSNs scenario. This adaptation has been standardized with the name of IPv6 over Low power Wireless Personal Area Networks (6LoWPAN). In this paper the first adaptation of the SPEED geographic routing algorithm in a 6LoWPAN scenario is presented and its experimental validation in a real testbed is shown as compared with the AODVprotocol. Avoiding route creation time and showing reduced memory occupation, load balancing and flow shaping properties SPEED is an effective solution to support packet routing in 6LoW-PAN networks.

A low-cost vehicle counter for next-generation ITS

This paper describes a vehicle counter application to be used in low-cost and low-complexity devices to be deployed in next-generation pervasive Intelligent Transport Systems. The first part of the paper introduces the Linesensor theory, which exploits the temporal redundancy of the movement to enable the processing of a 1D images (i.e. lines), thus reducing the complexity for extracting features and understanding the environment. Because of the high speed of the objects to be detected, the proposed application requires a very high frame rate and consequently an optimised design for the whole computer vision pipeline. For these reasons, in the second part of the paper, we propose a low-complexity background modelling algorithm permitting to extract information related to the whole image from a single metric. Our arguments demonstrate that the proposed algorithm has comparable performance in the segmentation operation as other state-of-the-art techniques, but reducing significantly the computational cost.

Architecture, Functional Requirements, and Early Implementation of an Instrumentation Grid for the IoT

This paper presents an innovative architecture for the instrumentation layer of a pervasive large-scale information system. State of the art examples already include an instrumentation layer in a grid infrastructure; nontheless these systems were not designed for large-scale ad-hoc networks, rapidly deployed, continuously upgraded, and dynamically reconfigured when the system is on-line. The main contribution is that of designing an instrumentation layer coherent with existing infrastructures capable of being federated with others, and already providing robust virtualization services in what concerns user authentication and access, distributed storage, and computing power. The large-scale instrumentation layer is inspired by the Internet of Things, and will consist of a large number of autonomous nodes organized in Wireless Sensor Networks and accessing the Internet following the 6LoWPAN specifications. An early implementation of this architecture is proven to respond to use cases centered on data- and event-driven services; it also permits a large degree of flexibility and adaptiveness in end nodes applications.

Web services transactions in 6LoWPAN networks [1]

HTTP is a widely used protocol for Web transactions and it is oriented to virtual resource management through URL mapping. The concept of resource in HTTP perfectly matches event notion in embedded devices, but HTTP can exhaust memory and processing in embedded systems. CoAP is an adaptation for resource constraint devices, it follows REST architecture and allows event communication and device control. We implemented this protocol for Erika OS using a State-Machine for efficient code management. We present a demo for the use of web services in a 6LoWPAN network to handle events in a simulated scenario of fire hazard.

Lightweight error correction technique in industrial IEEE802.15.4 networks

Industrial Wireless Sensor Networks (IWSNs) are nowadays becoming more and more popular thanks to their flexibility and pervasive monitoring capabilities to support process automation and remote maintenance applications. In such a scenario, channel errors due to the wireless medium can result in data packet losses, and consequently in unreliable IWSN services. To mitigate the above reported problem, this paper presents a lightweight error correction scheme specially developed for IEEE802.15.4-based IWSNs. By adding error correction and detection information inside the IEEE802.15.4 MAC data frame, the proposed FEC scheme is able to guarantee a backward compatibility with the standard while providing advanced capabilities in recovering data packets affected by bit errors. In the paper the benefits of the proposed technique are first evaluated through simulated loss traces, then they are validated in a real environment by considering real loss traces collected in an electricity power plant. The proposed error correction scheme is able to recover around 50% of the data packets that would be lost in case of a standard communication without any error correction capability.

SPEED-3D: a geographic routing protocol for 6LoWPAN networks

The integration of the wireless sensor network WSN technology in the internet world is a necessary step towards the full accomplishment of the internet of things IoT vision. In order to reach a seamless integration of tiny mote devices in internet, the IPv6 addressing method and communication protocols developed for the IoT must be modified or adapted to match the WSN requirements. This adaptation process is started in the 2007 with the standardisation of the IPv6 protocol over low power wireless personal area networks 6LoWPAN. In such a scenario, we propose SPEED-3D, an extension of the SPEED geographic routing algorithm, adapted to 6LoWPAN networks that caters for 3D routing. SPEED-3D avoids the creation of routing tables, and has a very low memory occupation; it also supports load balancing and flow shaping; finally, thanks to the presented extension, it is able to work seamlessly in a 3D setting e.g., a tall building. In the paper, we first present SPEED-3D in 6LoWPAN networks by detailing the encapsulation of all messages in the IEEE802.15.4 medium access control MAC protocol and the new functionality provided thanks to the IPv6 standard, then we present its implementation on a real-time kernel and its performance in a realistic indoor scenario.