Jaime Chen

A survey on quality of service support in wireless sensor and actor networks: Requirements and challenges in the context of critical infrastructure protection

Wireless sensor and actor networks (WSANs) are likely to become a pervasive technology in the near future due to the special characteristics of these devices and to the great number of applications where it can be applied. One of these applications is the critical infrastructure protection (CIP). In fact, WSANs have actually been identified as having the potential to become an integral part of the CIP. However, in order to achieve that goal, WSANs need to provide a set of features which includes a robust QoS. Unfortunately QoS support mechanisms in WSANs are still largely undeveloped. This paper studies the state-of-the-art of QoS management in WSANs by exploring existing proposals, challenges and open issues in the field. Emphasis is put on QoS in the context of CIP by focusing on the QoS requirements and the needs of CIP applications. Existing middleware and protocols are surveyed and the challenges and open issues in the field are presented.

An Integrated WSAN and SCADA System for Monitoring a Critical Infrastructure

Wireless sensor and actuator networks (WSAN) constitute an emerging technology with multiple applications in many different fields. Due to the features of WSAN (dynamism, redundancy, fault tolerance, and self-organization), this technology can be used as a supporting technology for the monitoring of critical infrastructures (CIs). For decades, the monitoring of CIs has centered on supervisory control and data acquisition (SCADA) systems, where operators can monitor and control the behavior of the system. The reach of the SCADA system has been hampered by the lack of deployment flexibility of the sensors that feed it with monitoring data. The integration of a multihop WSAN with SCADA for CI monitoring constitutes a novel approach to extend the SCADA reach in a cost-effective way, eliminating this handicap. However, the integration of WSAN and SCADA presents some challenges which have to be addressed in order to comprehensively take advantage of the WSAN features. This paper presents a solution for this joint integration. The solution uses a gateway and a Web services approach together with a Web-based SCADA, which provides an integrated platform accessible from the Internet. A real scenario where this solution has been successfully applied to monitor an electrical power grid is presented.

PS-QUASAR: A publish/subscribe QoS aware middleware for Wireless Sensor and Actor Networks

It has been more than 30 years since the first research into Wireless Sensor and Actor Networks appeared. However, WSANs are still not a ubiquitous technology due to several factors which include a lack of Quality of Service (QoS) support or the absence of high level programming models. New applications with heterogeneous QoS requirements where WSANs can be successfully applied, such as Critical Infrastructure Protection (CIP), have been recognized. PS-QUASAR, a middleware for WSANs that deals with these two issues, offers a high level simple programming model based on the publish/subscribe paradigm. In this model all nodes in the network are potential publishers of each of the topics. PS-QUASAR also handles QoS (reliability, deadline, priority) and supports a many-to-many exchange of messages between nodes in a fully distributed way by means of multicasting techniques. Performance evaluation via simulation using the Contiki operating system shows that the protocol can handle multiple publishers and subscribers at the same time whilst dealing with QoS requirements.

A service-oriented approach to facilitate WSAN application development

Due to the complex nature of developing Wireless Sensor and Actor Network (WSAN) applications it is obvious that new frameworks, tools, middleware and higher-level abstractions are needed to make the task of the developers easier. Depending on the WSAN system we want to develop, different characteristics must be taken into account but, perhaps, some of the most important are the capacity to add real-time constraints, the QoS and, of course energy saving. Our proposal USEME is a service-oriented and component-based framework which allows the easy combination of macro-programming and node-centric programming to develop real-time and efficient applications over WSANs. USEME allows the specification of real-time constraints between services, permits the use of groups to structure the network and is platform independent. Two prototypes (Imote2.Net and SunSPOT) have been implemented and several performance tests have been carried out.

A Service-Oriented Middleware for Wireless Sensor and Actor Networks

Wireless Sensor and Actor Networks are potentially one of the most important technologies of this century. There are many fields where they can be used in order to develop varied and interesting applications: high security environments, environmental monitoring, objects and events detection, military surveillance and precision agriculture. On the other hand, the ease of programming is a major barrier to the adoption of this kind of system. Recently, different high-level programming abstractions and middleware have appeared as promising solutions. In this paper, a middleware is proposed for USEME, a Service-Oriented Framework focussed on the deployment of lightweight services in sensors and actors. The high-level model supported abstracts application programmers from implementation tasks such as discovery, communication, group formation or real-time constraints.

USEME: A Service-Oriented Framework for Wireless Sensor and Actor Networks

We are in the presence of a new and powerful technology called wireless sensor and actor networks. There are many fields where we can apply this technology to develop varied and interesting applications: high security environments, environmental monitoring,industrial monitoring, medicine, precision agriculture. This technology brings the need to develop new frameworks in order to make easier the application developers task. Recently, different high-level programming abstractions and middleware have appeared as promising solutions. In this paper, a new service-oriented framework is introduced. The general scheme of the framework and a detailed description of the programming model are presented. The approach is oriented to deploy lightweight services on sensors and actors.Services can be composed among them by means of the port concept to form complex ad-hoc systems. A building monitoring and control application is described as a motivation example and it is used along the paper in order to show the expressiveness and usability of the abstract programming language proposed.

RAISE: RAIlway Infrastructure Health Monitoring Using Wireless SEnsor Networks

Wireless Sensor Networks are composed of devices of reduced size, self-powered and with wireless transmission capabilities. Because of these features this technology has been recognised as promising for a large variety of monitoring and surveillance applications. Moreover, WSNs have been identified as having the potential to become an integral part of the protection of critical infrastructures (CIP). In this paper we present the details of an application that makes use of WSNs to monitor railway infrastructures. The WSN collects information about the structural health and behavior of the infrastructure when a train travels along it and relays the readings to a base station. The base station uses the next train(s) as a data mule to upload the information. The information is then processed on the train which does not have the limitations of a sensor node. The use of a train as a data mule is especially suitable to collect information from remote or inaccessible places which do not have a direct connection to the internet. The application has been built using a publish/subscribe middleware called PS-QUASAR over Tmote sky nodes. The results of the simulation using the Cooja simulator are presented in this paper and confirm the feasibility of the application.

Sensor4PRI: A Sensor Platform for the Protection of Railway Infrastructures

Wireless Sensor Networks constitute pervasive and distributed computing systems and are potentially one of the most important technologies of this century. They have been specifically identified as a good candidate to become an integral part of the protection of critical infrastructures. In this paper we focus on railway infrastructure protection and we present the details of a sensor platform designed to be integrated into a slab track system in order to carry out both installation and maintenance monitoring activities. In the installation phase, the platform helps operators to install the slab tracks in the right position. In the maintenance phase, the platform collects information about the structural health and behavior of the infrastructure when a train travels along it and relays the readings to a base station. The base station uses trains as data mules to upload the information to the internet. The use of a train as a data mule is especially suitable for collecting information from remote or inaccessible places which do not have a direct connection to the internet and require less network infrastructure. The overall aim of the system is to deploy a permanent economically viable monitoring system to improve the safety of railway infrastructures.

NeuralSens: A neural network based framework to allow dynamic adaptation in wireless sensor and actor networks

Wireless Sensor and Actor Networks (WSANs) constitute a new way of distributed computing and are steadily gaining importance due to the wide variety of applications that can be implemented with them. As a result they are increasingly present everywhere (industry, farm use, buildings, etc.). However, there are still many important areas in which the WSANs can be improved. One of the most important aspects is to give the sensor networks the capability of being wirelessly reprogrammed so that developers do not have to physically interact with the sensor nodes. Many proposals that deal with this issue have been proposed, but most of them are hardly dependent on the operating system and demand a high energy consumption, even if only a small change has been made in the code. In this work, we propose a new way of wirelessly reprogramming based on the concept of neural networks. Unlike most of the existing approaches, our proposal is independent of the operating system and allows small pieces of code to be reprogrammed with a low energy consumption. The architecture developed to achieve that is described and case studies are presented that show the use of our proposal by means of practical examples.

On blockchain and its integration with IoT. Challenges and opportunities

Abstract In the Internet of Things (IoT) vision, conventional devices become smart and autonomous. This vision is turning into a reality thanks to advances in technology, but there are still challenges to address, particularly in the security domain e.g., data reliability. Taking into account the predicted evolution of the IoT in the coming years, it is necessary to provide confidence in this huge incoming information source. Blockchain has emerged as a key technology that will transform the way in which we share information. Building trust in distributed environments without the need for authorities is a technological advance that has the potential to change many industries, the IoT among them. Disruptive technologies such as big data and cloud computing have been leveraged by IoT to overcome its limitations since its conception, and we think blockchain will be one of the next ones. This paper focuses on this relationship, investigates challenges in blockchain IoT applications, and surveys the most relevant work in order to analyze how blockchain could potentially improve the IoT.