EnvironmetricsPub Date : 2026-07-28DOI: 10.1002/env.70124
Gianna Agrò, Mariantonietta Ruggieri
{"title":"A Functional Principal Component Analysis Framework for Vibration-Based Structural Condition Assessment of Highway Bridge Spans","authors":"Gianna Agrò, Mariantonietta Ruggieri","doi":"10.1002/env.70124","DOIUrl":"https://doi.org/10.1002/env.70124","url":null,"abstract":"<p>The management of lifespan and safety performance, aimed at ensuring the structural integrity and durability of highway infrastructure, has become an increasingly important area of research. In civil engineering, traditional methods for evaluating dynamic behavior, such as Operational Modal Analysis and the Peak Picking technique, often fall short in detecting subtle signs of damage. This study proposes a novel approach based on Functional Principal Component Analysis (FPCA) to enhance the sensitivity of vibration-based structural condition and anomaly assessment. A preliminary analysis based on classical PCA applied to the same dataset was previously presented in Agrò et al. (2025a). That study highlighted the capability of PCA to capture dominant variance patterns in the vibration signals. However, PCA operates on discretized time series and does not explicitly account for their functional nature. In contrast, the FPCA framework proposed in this study models the signals as continuous functions, enabling a more refined characterization of temporal variability and improving sensitivity to subtle structural differences. By comparing the optimal functional subspaces derived from FPCA for both intact and potentially compromised bridge spans, we quantify structural differences through the cosine of principal angles. The approach is applied to a real case involving a viaduct on the Palermo–Catania highway, demonstrating its potential to reveal anomalies not evident through conventional modal analysis.</p>","PeriodicalId":50512,"journal":{"name":"Environmetrics","volume":"37 6","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/env.70124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148616415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
EnvironmetricsPub Date : 2026-07-25DOI: 10.1002/env.70123
Chunzheng Cao, Wenzhu Chen, Xiaoxin Zhu
{"title":"Hierarchical Spatio-Temporal Model Under \u0000 \u0000 \u0000 t\u0000 \u0000 $$ t $$\u0000 -Process With Application","authors":"Chunzheng Cao, Wenzhu Chen, Xiaoxin Zhu","doi":"10.1002/env.70123","DOIUrl":"https://doi.org/10.1002/env.70123","url":null,"abstract":"<div>\u0000 \u0000 <p>Gaussian process has been widely used in spatio-temporal models to analyze and reveal the underlying correlation of spatio-temporal data. Nevertheless, inferences drawn from Gaussian process-based models can be highly sensitive to outliers or distributional misspecifications. To enhance robustness, we propose a robust hierarchical spatio-temporal model based on Student-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>t</mi>\u0000 </mrow>\u0000 <annotation>$$ t $$</annotation>\u0000 </semantics></math> process framework to enable reliable inferences under data contamination. The proposed model employs two independent <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>t</mi>\u0000 </mrow>\u0000 <annotation>$$ t $$</annotation>\u0000 </semantics></math>-processes to respectively describe the latent spatial random effects and random errors, thereby ensuring robust inferences against various types of outliers. A variational Expectation-Maximization algorithm is developed for efficient parameter estimation and prediction. Simulation studies demonstrate that the proposed model delivers reliable and accurate results even when the data are contaminated by substantial outliers. The practical usefulness of the model is further illustrated through an application to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mtext>PM</mtext>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>2</mn>\u0000 <mo>.</mo>\u0000 <mn>5</mn>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {mathrm{PM}}_{2.5} $$</annotation>\u0000 </semantics></math> concentration data, highlighting its effectiveness in robust spatio-temporal inference.</p>\u0000 </div>","PeriodicalId":50512,"journal":{"name":"Environmetrics","volume":"37 6","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148615855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}