José F. Martínez

QoS in wireless sensor networks: survey and approach

A wireless sensor network (WSN) is a computer wireless network composed of spatially distributed and autonomous tiny nodes -- smart dust sensors, motes -, which cooperatively monitor physical or environmental conditions. Nowadays these kinds of networks support a wide range of applications, such as target tracking, security, environmental control, habitat monitoring, source detection, source localization, vehicular and traffic monitoring, health monitoring, building and industrial monitoring, etc. Many of these applications have strong requirements for end-to-end delay and losses during data transmissions. In this work we have classified the main mechanisms that have been proposed to provide Quality of Service (QoS) in WSN at Medium Access Control (MAC) and network layers. Finally, taking into account some particularities of the studied MAC- and network-layer protocols, we have selected a real application scenario in order to show how to choose an appropriate approach for guaranteeing performance in a WSN deployed application.

Knowledge-Aware and Service-Oriented Middleware for deploying pervasive services

Many applications and services have emerged in the frame of new Internet of Things paradigm. This novel view has opened the Web services to a variety of devices especially to tiny and resource-constrained devices. Wireless Sensor and Actuator Networks belong to that kind of devices. Those networks have become one of the more promising technologies to take part in the Future Internet. However, the integration of Sensor and Actuator Networks into the Service Cloud is a hard challenge requiring specific new architectures and protocols. This paper presents a middleware approach addressing this important issue. A Knowledge-Aware and Service-Oriented Middleware (KASOM) for pervasive embedded networks is proposed. The major aim of KASOM is to offer advanced and enriched pervasive services to everyone connected to Internet. In this sense, KASOM implements mechanisms and protocols which allow managing the knowledge generated in pervasive embedded networks in order to expose it to Internet users in a readable way. General functional requirements of embedded sensor and actuator platforms have been taken into account when designing KASOM, with special attention in energy consumption, memory and bandwidth. The KASOM evaluation and validation will be demonstrated through a real Wireless Sensor and Actuator Network deployment based on integral healthcare services in a sanatorium.

Pervasive smart spaces and environments : a service-oriented middleware architecture for wireless Ad Hoc and sensor networks

In the twenty-first century, the impact of wireless and ubiquitous technologies is changing the way people perceive and interact with the physical world. These communication paradigms promise to change and redefine, in a reasonably short period of time, the most common way of our everyday living. The continuous advances in the field of Wireless Sensor Networks and their direct application in Smart Spaces are clear examples of it. However, in order for this kind of new generation infrastructures to have a large-scale dissemination, there are still some open issues to tackle. In this way, this paper presents nSOM, a service-oriented framework based on sensor network design that provides internetworking services with the Internet cloud. This lightweight middleware architecture implements an agent-based virtual sensor service approach which is a compact semantic knowledge management scheme based on a dynamic composition model.

Building service-oriented Smart Infrastructures over Wireless Ad Hoc Sensor Networks: A middleware perspective

The increase in physical resources for the next-generation of embedded computing devices, as well as in the efforts carried out by the scientific and research communities, is paving the way for Smart Infrastructures based on Wireless Sensor Networks. In such manner, not only open and formally defined Service-Oriented Frameworks are required, but also efficient middleware technologies that ease the development of new sensor-based services. From the cornerstone analysis of pervasive computing principles applied to Smart Spaces creation, this article presents the @mSMS (micro Subscription Management System) middleware. This approach specifies and develops the notion of virtual sensor services created for Smart Environments over sensor networks from tiny in-network services based on agent technology. In the framework of the @mSWN European Research Project, this architecture has been validated in a Smart Hospital real-world scenario using a healthcare virtual sensor service. Considering such purpose, medical status monitoring, location tracking and perimeter surveillance agent-based services have been developed. This study is concluded by a comparative analysis of the system considering memory overhead, packet delivery ratio, average end-to-end delay and battery lifetime as evaluation metrics. The results show a lightweight middleware implementation with good overall system and network performance.

Composition and deployment of e-Health services over Wireless Sensor Networks

Providing necessary background for provisioning of a new generation of enriched services over Wireless Sensor Networks is the main effort that the scientific community is currently carrying out. These services have improved a great number of aspects related to pervasive systems such as saving resources, efficiency, reliability, scalability and low power consumption. In this paper, @mSMS middleware, using an event-based service model, is presented. This novel approach makes up the design requirements previously mentioned by implementing a dynamic memory kernel and a variable payload multiplexing mechanism for the information events in order to provide advanced services. The results obtained over real-world deployments, especially those related with provision of e-Health services, reflect a significant improvement over other similar proposals, such as the RUNES approach: 50% lower memory overhead, 53% lower software components load time and 12% lower events propagation time.

Exhaustif®: a fault injection tool for distributed heterogeneous embedded systems

This paper presents Exhaustif®, a SWIFI fault injection tool for fault tolerance verification and the validation of embedded software in distributed heterogeneous systems. Exhaustif® mainly consists of two parts: EEM and FIK. Exhaustif® Executive Manager (EEM) is a GUI Java application to define the fault injection campaign that uses a SQL database to save the test results obtained from the System under Test (SUT) in order to carry out a post injection data analysis. FIK is under the command of EEM to cary out fault injections in applications running under diverse operating systems using pure SWIFI techniques. Exhaustif® carries out floating point register and memory corruptions using temporary triggers and uses an optimized routine interception mechanism to carry out argument and return value corruption with a minimal time overhead. Two experimental Fault Injector Kernels (FIK) under the RTEMS operating system for an EADS-Astrium SPARC ERC32-based MCM processor board and i386 standard PC mainboard have been developed.

The DiY Smart Experiences Project

In this chapter we discuss the wide range of challenges in user-generated Internet of Things applications, as being worked on among the large consortium of the DiY Smart Experiences (DiYSE) project (DiYSE, ITEA2 08005). The chapter starts with a discussion on the context of ‘DiY’ as a phenomenon to be leveraged, and eco-awareness as an example application area. The main body of the chapter is devoted to the technical outline of the DiYSE architecture, starting at the lower Internet of Things layers of sensors, actuators and middleware, over the role of semantics in device and service interoperability, up to requirements for the service framework and the application creation process. Furthermore, the chapter adds considerations concerning tangible interaction in the smart space, assumed in Di- YSE both for the context of experiencing as well as shaping the user experience. With the chapter, we thus take a holistic view, sampling the range from lowerlayer technical implications of enabling DiY creation in the Internet of Things, up to the human-level aspects of creative communities as well as tangible interaction.

XML schema based fault set definition to improve fault injection tools interoperability

Software implemented fault injection tools (SWIFI) use fault injectors to carry out the fault injection campaign defined in a GUI-based application. However, the communication between the fault injector and the application is defined in an ad-hoc manner. This paper describes an XML schema formalisation approach for the definition of fault sets which specify low level memory and/or register value corruptions in embedded microprocessor-based systems and resource usage faults in host based systems. Through this proposed XML schema definition, different injectors could be used to carry out the same fault set injection. To validate this approach an experimental tool called Exhaustif®, consisting of a GUI Java application for defining the fault sets and injection policies, one injector for Windows hosts systems and two injectors for Sparc and i386 architectures under RTEMS have been developed.

Security Framework for DPWS Compliant Devices

The DPWS (Devices Profile for Web Services) specification enables devices, including small-scale ones, to be integrated seamlessly in a service oriented architecture (SOA). Complex enterprise applications are able to access devices functionalities in a Web Service fashion. In some cases, specific applications might require secure transactions that even devices with resources constraints must meet. Devices with hardly 10KB of run time memory and low speed processors might slow down or run out of memory when ciphering or signing large secure messages. This paper proposes a security model that complies with existing security specifications for Web Services and optimizes resources consumptions in such devices.

Modelling QoS for wireless sensor networks

A wireless sensor network (WSN) is a wireless network composed of spatially distributed and tiny autonomous nodes — smart dust sensors, motes —, which cooperatively monitor physical or environmental conditions. Nowadays these kinds of networks support a wide range of applications, such as target tracking, security, environmental control, habitat monitoring, source detection, source localization, vehicular and traffic monitoring, health monitoring, building and industrial monitoring, etc. Generally, these applications have strong and strict requirements for end-to-end delaying and loosing during data transmissions. In this paper, we propose a realistic scenario for application of the WSN field in order to illustrate selection of an appropriate approach for guaranteeing performance in a WSN-deployed application. The methodology we have used includes four major phases: 1) Requirements analysis of the application scenario; 2) QoS modeling in different layers of the communications protocol stack and selection of more suitable QoS protocols and mechanisms; 3) Definition of a simulation model based on an application scenario, to which we applied the protocols and mechanisms selected in the phase 2; and 4) Validation of decisions by means of simulation and analysis of results. This work has been partially financed by the “Universidad Politecnica de Madrid” and the “ Comunidad de Madrid” in the framework of the project CRISAL - M0700204174.