Fabio Federici

An Integrated Approach to the Design of Wireless Sensor Networks for Structural Health Monitoring

Wireless Sensor Networks are a promising technology for the implementation of Structural Health Monitoring systems, since they allow to increase the diffusion of measurements in the structure and to reduce the sensor deployment effort and the overall costs. In this paper, possible benefits and critical issues related with the use of Wireless Sensor Networks for structural monitoring are analysed, specifically addressing network design strategies oriented to the damage detection problem. A global cost function is defined and used for the definition of possible design methodologies. Among the various approach, the use of an integrated strategy, able to take advantage of a preliminary structural analysis is considered. Moreover, the implementation of a distributed processing is an explored strategy for an overall improvement of system performances. Benefits of this methodology are finally demonstrated through the analysis of a representative case study, the IASC-ASCE benchmark problem.

Distributed Structural Monitoring for a Smart City in a Seismic Area

The concept of Smart City (SC) has been introduced to categorize the vast area of activities to enhance the life quality of citizen, which are characterised by a pervasive use of Information and Communication Technologies (ICT), to help cities, with various urban domains, making better use of their resources. Monitoring the structural behaviour of strategic buildings and monuments may be desirable for citizens, which have recently experienced a destructive earthquake in their own town, such as the case of L’Aquila. The paper deals with the design of a distributed structural monitoring network for a selected set of strategic structures belonging to the city of L’Aquila. Preliminary design criteria are discussed on the basis of previous authors’ experiences in this context. Specific attention has been dedicated to analyse the expected acceleration response measurements induced by small seismic excitations for the general purpose of monitoring.

A design methodology for soft-core platforms on FPGA with SMP Linux, OpenMP support, and distributed hardware profiling system

In recent years, the use of multiprocessor systems has become increasingly common. Even in the embedded domain, the development of platforms based on multiprocessor systems or the porting of legacy single-core applications are frequent needs. However, such designs are often complicated, as embedded systems are characterized by numerous non-functional requirements and a tight hardware/software integration. This work proposes a methodology for the development and validation of an embedded multiprocessor system. Specifically, the proposed method assumes the use of a portable, open source API to support the parallelization and the possibility of prototyping the system on a field-programmable gate array. On this basis, the proposed flow allows an early exploration of the hardware configuration space, a preliminary estimate of performance, and the rapid development of a system able to satisfy the design specifications. An accurate assessment of the actual performance of the system is then enforced by the use of an hardware-based profiling subsystem. The proposed design flow is described, and a version specifically designed for LEON3 processor is presented and validated. The application of the proposed methodology in a real case of industrial study is then presented and analyzed.

Design and validation of multi-core embedded systems under time-to-prototype and high performance constraints

This work deals with the problem of developing embedded multi-core systems, under time-to-prototype and high performance constraints, by exploiting reconfigurable logic. In particular, the paper focuses on the early analysis activities, performed by means of native simulation technologies, and then on the full development of an embedded multi-core platform composed of four LEON3 soft-processors and able to support the execution of OpenMP based applications. Moreover, in order to evaluate software execution time at run-time, a distributed hardware profiling mechanism has been inserted into the final implementation to monitor the whole system. The final goal is the definition and the exploitation of a high-level design and validation methodology able to exploit both a well-known parallel execution paradigm and a run-time system monitoring service. Correctness and performance of such a platform have been evaluated by means of specific benchmarks.

Analysis and Implementation of Distributed Data Processing in a Wireless Sensor Network for Structural Health Monitoring

In recent years, there has been a growing interest for possible application of wireless smart sensor networks. One area in which these platforms can offer considerable advantages over classical solutions is the monitoring of civil structures. This work analyze possible benefits and critical issues associated with the use of wireless sensor networks for vibrational monitoring of civil infrastructures. On the basis of the analysis of an experimental setup for the health monitoring of an heritage structure, the main advantages and limitations of a wireless sensor network for vibrational monitoring are outlined. A possible approach for the design of a sensor node supporting on-board vibrational data processing is discussed. Possible advantages of the proposed architecture are analyzed and a preliminary characterization of a custom prototype is presented.

An accelerometer digital front end for efficient seismic event detection support in a wireless sensor node

Rapid detection of earthquake-induced acceleration in civil structures is a key tool for the implementation of early warning strategies. This work illustrates the development of a digital front end able to effectively support seismic data analysis and specifically designed for integration in MEMS accelerometers. Although there are some examples of commercially available sensors integrating processing blocks, few are able to satisfy seismic monitoring applications requirements. Proposed front end is based on the Walsh transform and it is specifically designed to support efficient seismic event detection in a battery-powered wireless sensor node. Hardware architecture of proposed block is described and its capabilities are detailed. Detection accuracy is evaluated by means of real world structural data analysis.