Large SHM datasets often result from special applications such as long-term monitoring, dense sensor arrays, or high sampling rates. Through the development of novel sensing techniques as well as advances in sensing devices and data acquisition technology, it is expected that such large volumes of measurement data become commonplace. In anticipation of datasets magnitudes larger than today's, it is important to evaluate current SHM processing methods at BIGDATA standards and identify potential limitations within computational procedures. This paper will focus on the processing of large SHM datasets and the computational sensitivity of common SHM procedures. Processing concerns encompass efficiency and scalability of SHM software, particularly the computational sensitivity of common system identification and damage detection algorithms with respect to a large amount of sensors and samples.
IntroductionThe data acquisition process plays a key role in the monitoring of structural systems. Over the years, sensing networks have evolved from basic to complex. Today, structural response quantities are measured with high resolution in time and space by means of wired and wireless contact sensors as well as noncontact digital camera lenses. In order to infer about structural health condition, the measured signals are processed through various SHM algorithms (system identification, model calibration, and damage detection). Therefore, along with improvement in sensing technology, it is critical to evaluate the performance of SHM algorithms to study their scalability potential and overcome possible limitations in processing large SHM datasets. Toward this goal, this paper investigates performance of a subset of the current SHM procedures with growth of network size and data acquisition interval. This investigation is conducted in two parts: the preprocessing of measured data as the first step in any SHM procedure, and the computational cost of certain system identification and damage detection algorithms. Although it is expected that BIGDATA storage requirements will be far greater than limits of local hard disks and RAM, this aspect of the problem is outside of the scope of this paper.
Exactly How Big Is "BIGDATA"?Today, a dataset earns the title "large" from the sizes of its dimensions and storage space. SHM datasets are typically multivariate times series with two dimensions: number of sensors and number of time samples. However, the mere storage requirements, say in megabytes, of a dataset is not enough to constitute the title "BIGDATA". Inherently, BIGDATA requires "BIGPROCESSING", a subsequent analysis of BIGDATA, of which computational complexity varies among SHM applications and techniques.