Matching hierarchical structures for shape recognition

In this thesis we aim to develop a framework for clustering trees and rep- resenting and learning a generative model of graph structures from a set of training samples. The approach is applied to the problem of the recognition and classification of shape abstracted in terms of its morphological skeleton. We make five contributions. The first is an algorithm to approximate tree edit-distance using relaxation labeling. The second is the introduction of the tree union, a representation capable of representing the modes of structural variation present in a set of trees. The third is an information theoretic approach to learning a generative model of tree structures from a training set. While the skeletal abstraction of shape was chosen mainly as a exper- imental vehicle, we, nonetheless, make some contributions to the fields of skeleton extraction and its graph representation. In particular, our fourth contribution is the development of a skeletonization method that corrects curvature effects in the Hamilton-Jacobi framework, improving its localiza- tion and noise sensitivity. Finally, we propose a shape-measure capable of characterizing shapes abstracted in terms of their skeleton. This measure has a number of interesting properties. In particular, it varies smoothly as the shape is deformed and can be easily computed using the presented skeleton extraction algorithm. Each chapter presents an experimental analysis of the proposed approaches applied to shape recognition problems

Quantum Coherence in Biological Systems

Ph.DDOCTOR OF PHILOSOPH

Geotechnical Engineering for the Preservation of Monuments and Historic Sites III

The conservation of monuments and historic sites is one of the most challenging problems facing modern civilization. It involves, in inextricable patterns, factors belonging to different fields (cultural, humanistic, social, technical, economical, administrative) and the requirements of safety and use appear to be (or often are) in conflict with the respect of the integrity of the monuments. The complexity of the topic is such that a shared framework of reference is still lacking among art historians, architects, structural and geotechnical engineers. The complexity of the subject is such that a shared frame of reference is still lacking among art historians, architects, architectural and geotechnical engineers. And while there are exemplary cases of an integral approach to each building element with its static and architectural function, as a material witness to the culture and construction techniques of the original historical period, there are still examples of uncritical reliance on modern technology leading to the substitution from earlier structures to new ones, preserving only the iconic look of the original monument. Geotechnical Engineering for the Preservation of Monuments and Historic Sites III collects the contributions to the eponymous 3rd International ISSMGE TC301 Symposium (Naples, Italy, 22-24 June 2022). The papers cover a wide range of topics, which include: 　 - Principles of conservation, maintenance strategies, case histories - The knowledge: investigations and monitoring - Seismic risk, site effects, soil structure interaction - Effects of urban development and tunnelling on built heritage - Preservation of diffuse heritage: soil instability, subsidence, environmental damages The present volume aims at geotechnical engineers and academics involved in the preservation of monuments and historic sites worldwide

Transmissibility-based monitoring and combination of damage feature decisions within a holistic structural health monitoring framework

Over the past forty years, intensive research has been carried out in the field of structural health monitoring (SHM), since the identification of damage at an early stage contributes to avoiding structural failure and reducing maintenance costs. In particular, the monitoring of wind turbines has gained special interest, since there is an increasing number of installed wind turbines worldwide and a large number of wind turbines which have reached or will soon reach their design lifespan. This thesis focuses on vibration-based SHM methods, which observe features describing the dynamics of a structure. Moreover, this work is based on the conception that the consideration of SHM should not only involve the observation of damage-sensitive features, but should also address further aspects, such as the effect of environmental and operational conditions (EOCs) and the statistical pattern recognition approaches used for decision making. Wind turbines are complex structures which operate in a challenging environment. Most of the vibration-based approaches rely on assumptions which are violated, for example, during the operation of a wind turbine, raising doubts concerning their accuracy. Furthermore, there is a plethora of damage-sensitive features, alternatively called condition parameters (CPs), which can be used to assess the state of a structure. However, up to the present moment, little research has been conducted on the combination of damage feature selected and on the exploitation of decision making processes for improving the detection rates of damage when it exists. This work introduces a new vibration-based CP, which does not rely on any significant assumptions. The new CP is based on an output-only version of an autoregressive model with exogenous input (ARX), which is essentially a transmissibility function (TF) model. The poles of the model are therefore called TF poles. The proposed CP is based on the observation of TF pole migration due to structural changes. Several experimental datasets are used to explore the sensitivity of TF poles to damage, while the concept of implementing TF poles as a CP in unsupervised mode is described. The new CP is integrated into a three-tier SHM framework which performs data normalizaton (tier 1), extracts the CP for analysis (tier 2) and subsequently makes use of hypothesis testing (tier 3). This framework using TF poles is validated on the fatigue test data of a full-scale rotor blade. This work also proposes the implementation of adaptive boosting (AdaBoost) for the combination of decisions obtained from several damage features in order to attain a new and more accurate decision rule. The proposed concept is integrated into the aforementioned three-tier SHM framework and is used for combining the decisions of vibration-based damage features. However, the proposed concept can be implemented after any SHM process, even if other SHM approaches are employed. The concept of implementing Adaboost within the three-tier SHM framework is outlined and validated on the data of an operating 3~kW wind turbine. Finally, different damage features, including the proposed CP, are compared with respect to their sensivity to damage and sensitivity to EOC variability based on rotor blade fatigue tests

Advances in Modelling and Prediction on the Impact of Human Activities and Extreme Events on Environments

YesThis book is an edition of the Special Issue Advances in Modelling and Prediction on the Impact of Human Activities and Extreme Events on Environments that was published in Water journal

Sustainable Land Use and Rural Development in Southeast Asia: Innovations and Policies for Mountainous Areas

Sustainable Development; Landscape/Regional and Urban Planning; Agricultur

Safety and Reliability - Safe Societies in a Changing World

The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen