Cyber-Physical Systems are experiencing a paradigm shift in which processing has been relocated to the distributed sensing layer and is no longer performed in a centralized manner. This approach, usually referred to as Edge Computing, demands the use of hardware platforms that are able to manage the steadily increasing requirements in computing performance, while keeping energy efficiency and the adaptability imposed by the interaction with the physical world. In this context, SRAM-based FPGAs and their inherent run-time reconfigurability, when coupled with smart power management strategies, are a suitable solution. However, they usually fail in user accessibility and ease of development. In this paper, an integrated framework to develop FPGA-based high-performance embedded systems for Edge Computing in Cyber-Physical Systems is presented. This framework provides a hardware-based processing architecture, an automated toolchain, and a runtime to transparently generate and manage reconfigurable systems from high-level system descriptions without additional user intervention. Moreover, it provides users with support for dynamically adapting the available computing resources to switch the working point of the architecture in a solution space defined by computing performance, energy consumption and fault tolerance. Results show that it is indeed possible to explore this solution space at run time and prove that the proposed framework is a competitive alternative to software-based edge computing platforms, being able to provide not only faster solutions, but also higher energy efficiency for computing-intensive algorithms with significant levels of data-level parallelism.

In this paper, we present the design and implementation of a prototype system of Smart Parking Services based on Wireless Sensor Networks (WSNs) that allows vehicle drivers to effectively find the free parking places. The proposed scheme consists of wireless sensor networks, embedded web-server, central web-server and mobile phone application. In the system, low-cost wireless sensors networks modules are deployed into each parking slot equipped with one sensor node. The state of the parking slot is detected by sensor node and is reported periodically to embedded web-server via the deployed wireless sensor networks. This information is sent to central web-server using Wi-Fi networks in real-time, and also the vehicle driver can find vacant parking lots using standard mobile devices.

In this paper, a methodology based on machine learning for fault detection in continuous processes is presented. It aims to monitor fully distributed scenarios, such as the Tennessee Eastman Process, selected as the use case of this work, where sensors are distributed throughout an industrial plant. A hybrid feature selection approach based on filters and wrappers, called Hybrid Fisher Wrapper method, is proposed to select the most representative sensors to get the highest detection quality for fault identification. The proposed methodology provides a complete design space of solutions differing in the sensing effort, the processing complexity, and the obtained detection quality. It constitutes an alternative to the typical scheme in Industry 4.0, where multiple distributed sensor systems collect and send data to a centralised cloud. Differently, the proposed technique follows a distributed approach, in which processing can be done eventually close to the sensors where data is generated, i.e., at the edge of the Internet of Things. This approach overcomes the bandwidth, privacy, and latency limitations that centralised approaches may suffer. The experimental results show that the proposed methodology provides Tennessee Eastman Process fault detection solutions with state-of-the-art detection quality figures. In terms of latency, solutions obtained outperform in 37.5 times the implementation with the highest detection quality, using 1.99 times fewer features, on average. Also, the scalability of the framework provides a design space where the optimal implementation can be chosen according to the application needs.

Object detection is an essential technology for surveillance systems, particularly in areas with a high risk of accidents such as railway level crossings. To prevent future collisions, the system must detect and track any object that passes through the monitored area with high accuracy, and this process must be performed fulfilling real-time specifications. In this work, an edge IoT HW platform implementation capable of detecting and tracking objects in a railway level crossing scenario is proposed. The response of the system has to be calculated and sent from the proposed IoT platform to the train, so as to trigger a warning action to avoid a possible collision. The system uses a low-resolution 3D 16-channel LIDAR as a sensor that provides an accurate point cloud map with a large amount of data. The element used to process the information is a custom embedded edge platform with low computing resources and low-power consumption. This processing element is located as close as possible to the sensor, where data is generated to improve latency, privacy, and avoid bandwidth limitations, compared to performing processing in the cloud. Additionally, lightweight object detection and tracking algorithm is proposed in this work to process a large amount of information provided by the LIDAR, allowing to reach real-time specifications. The proposed method is validated quantitatively by carrying out implementation on a car road, emulating a railway level crossing.

The use of reconfigurable hardware (HW) can improve the processing performance of many systems, including Wireless Sensor Networks (WSNs). Moreover, reconfigurable devices permit remote and runtime HW reconfiguration, which implies benefits in WSNs deployment and maintainability and, finally, cost reduction. In this paper, WSN node runtime reconfigurability is tackled from several aspects. First, the sensor node includes a commercial reconfigurable device, a Field Programmable Gate Array (FPGA), that permits to take advantage of the tools and support provided by the industry, while exploiting the inherent hardware parallelism. Second, two software (SW) and hardware reconfiguration scenarios are defined along with a support middleware. Third, in order to provide runtime reconfigurability to the WSN node, a complete runtime reconfigurable system has been defined and designed for the FPGA included in the node. Fourth, the HW reconfiguration cost has been evaluated, as well as the cost of transmitting new HW configurations and SW programs through the network, based on a set of defined parameters. Finally, the feasibility of the runtime reconfigurable system has been demonstrated with a use case.