Architectures for Wireless Sensor Networks

Various architectures have been developed for wireless sensor networks. Many of them leave to the programmer important concepts as the way in which the inter-task communication and dynamic reconfigurations are addressed. In this paper we describe the characteristics of a new architecture we proposed - the data-centric architecture. This architecture offers an easy way of structuring the applications designed for wireless sensor nodes that confers them superior performances

Deploying RIOT operating system on a reconfigurable Internet of Things end-device

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e ComputadoresThe Internet of Everything (IoE) is enabling the connection of an infinity of physical objects to the Internet, and has the potential to connect every single existing object in the world. This empowers a market with endless opportunities where the big players are forecasting, by 2020, more than 50 billion connected devices, representing an 8 trillion USD market. The IoE is a broad concept that comprises several technological areas and will certainly, include more in the future. Some of those already existing fields are the Internet of Energy related with the connectivity of electrical power grids, Internet of Medical Things (IoMT), for instance, enables patient monitoring, Internet of Industrial Things (IoIT), which is dedicated to industrial plants, and the Internet of Things (IoT) that focus on the connection of everyday objects (e.g. home appliances, wearables, transports, buildings, etc.) to the Internet. The diversity of scenarios where IoT can be deployed, and consequently the different constraints associated to each device, leads to a heterogeneous network composed by several communication technologies and protocols co-existing on the same physical space. Therefore, the key requirements of an IoT network are the connectivity and the interoperability between devices. Such requirement is achieved by the adoption of standard protocols and a well-defined lightweight network stack. Due to the adoption of a standard network stack, the data processed and transmitted between devices tends to increase. Because most of the devices connected are resource constrained, i.e., low memory, low processing capabilities, available energy, the communication can severally decrease the device’s performance. Hereupon, to tackle such issues without sacrificing other important requirements, this dissertation aims to deploy an operating system (OS) for IoT, the RIOT-OS, while providing a study on how network-related tasks can benefit from hardware accelerators (deployed on reconfigurable technology), specially designed to process and filter packets received by an IoT device.O conceito Internet of Everything (IoE) permite a conexão de uma infinidade de objetos à Internet e tem o potencial de conectar todos os objetos existentes no mundo. Favorecendo assim o aparecimento de novos mercados e infinitas possibilidades, em que os grandes intervenientes destes mercados preveem até 2020 a conexão de mais de 50 mil milhões de dispositivos, representando um mercado de 8 mil milhões de dólares. IoE é um amplo conceito que inclui várias áreas tecnológicas e irá certamente incluir mais no futuro. Algumas das áreas já existentes são: a Internet of Energy relacionada com a conexão de redes de transporte e distribuição de energia à Internet; Internet of Medical Things (IoMT), que possibilita a monotorização de pacientes; Internet of Industrial Things (IoIT), dedicada a instalações industriais e a Internet of Things (IoT), que foca na conexão de objetos do dia-a-dia (e.g. eletrodomésticos, wearables, transportes, edifícios, etc.) à Internet. A diversidade de cenários à qual IoT pode ser aplicado, e consequentemente, as diferentes restrições aplicadas a cada dispositivo, levam à criação de uma rede heterogénea composto por diversas tecnologias de comunicação e protocolos a coexistir no mesmo espaço físico. Desta forma, os requisitos chave aplicados às redes IoT são a conectividade e interoperabilidade entre dispositivos. Estes requisitos são atingidos com a adoção de protocolos standard e pilhas de comunicação bem definidas. Com a adoção de pilhas de comunicação standard, a informação processada e transmitida entre dispostos tende a aumentar. Visto que a maioria dos dispositivos conectados possuem escaços recursos, i.e., memória reduzida, baixa capacidade de processamento, pouca energia disponível, o aumento da capacidade de comunicação pode degradar o desempenho destes dispositivos. Posto isto, para lidar com estes problemas e sem sacrificar outros requisitos importantes, esta dissertação pretende fazer o porting de um sistema operativo IoT, o RIOT, para uma solução reconfigurável, o CUTE mote. O principal objetivo consiste na realização de um estudo sobre os benefícios que as tarefas relacionadas com as camadas de rede podem ter ao serem executadas em hardware via aceleradores dedicados. Estes aceleradores são especialmente projetados para processar e filtrar pacotes de dados provenientes de uma interface radio em redes IoT periféricas

A Structured Hardware/Software Architecture for Embedded Sensor Nodes

Owing to the limited requirement for sensor processing in early networked sensor nodes, embedded software was generally built around the communication stack. Modern sensor nodes have evolved to contain significant on-board functionality in addition to communications, including sensor processing, energy management, actuation and locationing. The embedded software for this functionality, however, is often implemented in the application layer of the communications stack, resulting in an unstructured, top-heavy and complex stack. In this paper, we propose an embedded system architecture to formally specify multiple interfaces on a sensor node. This architecture differs from existing solutions by providing a sensor node with multiple stacks (each stack implements a separate node function), all linked by a shared application layer. This establishes a structured platform for the formal design, specification and implementation of modern sensor and wireless sensor nodes. We describe a practical prototype of an intelligent sensing, energy-aware, sensor node that has been developed using this architecture, implementing stacks for communications, sensing and energy management. The structure and operation of the intelligent sensing and energy management stacks are described in detail. The proposed architecture promotes structured and modular design, allowing for efficient code reuse and being suitable for future generations of sensor nodes featuring interchangeable components

P4CEP: Towards In-Network Complex Event Processing

In-network computing using programmable networking hardware is a strong trend in networking that promises to reduce latency and consumption of server resources through offloading to network elements (programmable switches and smart NICs). In particular, the data plane programming language P4 together with powerful P4 networking hardware has spawned projects offloading services into the network, e.g., consensus services or caching services. In this paper, we present a novel case for in-network computing, namely, Complex Event Processing (CEP). CEP processes streams of basic events, e.g., stemming from networked sensors, into meaningful complex events. Traditionally, CEP processing has been performed on servers or overlay networks. However, we argue in this paper that CEP is a good candidate for in-network computing along the communication path avoiding detouring streams to distant servers to minimize communication latency while also exploiting processing capabilities of novel networking hardware. We show that it is feasible to express CEP operations in P4 and also present a tool to compile CEP operations, formulated in our P4CEP rule specification language, to P4 code. Moreover, we identify challenges and problems that we have encountered to show future research directions for implementing full-fledged in-network CEP systems.Comment: 6 pages. Author's versio

Multicriteria decision making for enhanced perception-based multimedia communication

This paper proposes an approach that integrates technical concerns with user perceptual considerations for intelligent decision making in the construction of tailor-made multimedia communication protocols. Thus, the proposed approach, based on multicriteria decision making (MDM), incorporates not only classical networking considerations, but, indeed, user preferences as well. Furthermore, in keeping with the task-dependent nature consistently identified in multimedia scenarios, the suggested communication protocols also take into account the type of multimedia application that they are transporting. Lastly, this approach also opens the possibility for such protocols to dynamically adapt based on a changing operating environment and user's preferences

Cognitive Sensor Platform

This paper describes a platform that is used to build embedded sensor systems for low energy implantable applications. One of the key characteristics of the platform is the ability to reason about the environment and dynamically modify the operational parameters of the system. Additionally the platform provides to ability to compose application specific sensor systems using a novel computational element that directly supports a synchronous-dataflow (SDF) programming paradigm. Cognition in the context of a sensor platform is defined as the “process of knowing, including aspects of awareness, perception, reasoning, and judgment”.DOI:http://dx.doi.org/10.11591/ijece.v4i4.568

Multicriteria decision making for enhanced perception-based multimedia communication

This paper proposes an approach that integrates technical concerns with user perceptual considerations for intelligent decision making in the construction of tailor-made multimedia communication protocols. Thus, the proposed approach, based on multicriteria decision making (MDM), incorporates not only classical networking considerations, but, indeed, user preferences as well. Furthermore, in keeping with the task-dependent nature consistently identified in multimedia scenarios, the suggested communication protocols also take into account the type of multimedia application that they are transporting. Lastly, this approach also opens the possibility for such protocols to dynamically adapt based on a changing operating environment and user’s preferences

The Design of a System Architecture for Mobile Multimedia Computers

This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies

Building Blocks for Adaptive Modular Sensing Systems

This thesis contributes towards the development of systems and strategies by which sensor and actuator components can be combined to produce flexible and robust sensor systems for a given application. A set of intelligent modular blocks (building blocks) have been created from which composite sensors (made up of multiple sensor and actuator components) can be rapidly reconfigured for the construction of Adaptive Modular Sensing Systems. The composite systems are expected to prove useful in several application domains including industrial control, inspection systems, mobile robotics, monitoring and data acquisition. The intelligent building blocks, referred to as transducer interface modules, contain embedded knowledge about their capabilities and how they can interact with other modules. These modules encapsulate a general purpose modular hardware architecture that provides an interface between the sensors, the actuators, and the communication medium. The geometry of each transducer interface module is a cube. A connector mechanism implemented on each face of the module enables physical connection of the modules. Each module provides a core functionality and can be connected to other modules to form more capable composite sensors. Once the modules are combined, the capabilities (e.g., range, resolution, sample rate, etc.) and functionality (e.g., temperature measurement) of the composite sensor is determined and communicated to other sensors in the enviornment. For maximum flexibility, a distributed software architecture is executed on the blocks to enable automatic acquisition of configuration-specific algorithms. This logical algorithm imparts a collective identity to the composite group, and processes data based on the capabilities and functionalities of the transducers present in the system. A knowledge representation scheme allows each module in the composite group to store and communicate its functionality and capabilities to other connected modules in the system