Recent years have seen a concurrent development of new sensor technologies and high-fidelity modeling capabilities. At the junction of these two topics lies an interesting opportunity for real-time system monitoring and damage assessment of structures. During monitoring, measurements from a structure are used to learn the parameters and equations characterizing a physics-based model of the system; thus enabling damage identification. Since monitored quantities are physical, these methods offer precious insight into the damage state of the structure (localization, type of damage and its extent). Furthermore, one obtains a model of the structure in its current condition, an essential element in predicting the future behavior of the structure and enabling adequate decision-making procedures. This dissertation focuses more specifically on solving some of the challenges associated with the use of online Bayesian learning algorithms, also called sequential filtering algorithms, for damage detection and characterization in nonlinear structural systems. A major challenge regarding online Bayesian filtering algorithms lies in achieving good accuracy for large dimensional systems and complex nonlinear non-Gaussian systems, where non-Gaussianity can arise for instance in systems which are not globally identifiable. In the first part of this dissertation, we show that one can derive algorithmic enhancements of filtering techniques, mainly based on innovative ways to reduce the dimensionality of the problem at hand, and thus obtain a good trade-off between accuracy and computational complexity of the learning algorithms. For instance, for particle filtering techniques (sampling-based algorithms) subjected to the so-called curse of dimensionality, the concept of Rao-Blackwellisation can be used to greatly reduce the dimension of the sampling space. On the other hand, one can also build upon nonlinear Kalman filtering techniques, which are very computationally efficient, and expand their capabilities to non-Gaussian distributions. Another challenge associated with structural health monitoring is the amount of uncertainties and variabilities inherently present in the system, measurements and/or inputs. The second part of this dissertation aims at demonstrating that online Bayesian filtering algorithms are very well-suited for SHM applications due to their ability to accurately quantify and take into account these uncertainties in the learning process. First, these algorithms are well-suited to address ill-conditioned problems, where not all parameters can be learnt from the available noisy data, a problem which frequently arises when considering large dimensional nonlinear systems. Then, in the case of unknown stochastic inputs, a method is derived to take into account in this sequential filtering framework unmeasured stationary excitations whose spectral properties are known but uncertain.

abstract: This research paper is a study of Sergei Taneyev’s Concert Suite for Violin and Orchestra, Op. 28 and includes Taneyev’s biography, a brief musical analysis which benefits the interpretation, and performance suggestions from the perspective of a concert violinist. The purpose of this paper is to enable performers to achieve a better understanding of this artwork and make informed musical choices. Sergei Ivanovich Taneyev (1856-1915) was a Russian composer. As a composition pupil of Tchaikovsky, and a teacher of Scriabin, Rachmaninoff, Lyapunov, and Glière, Taneyev is an important figure in Russian music. His compositions include operas, symphonies, chamber music, songs, and piano music. Taneyev’s style was influenced by Bach, Handel, Mozart, Glinka, Tchaikovsky, Wagner and various European composers. His cosmopolitan style, and wide-ranging compositional interests do not easily lend themselves generalization. This difficulty in categorizing his music along with his self-criticism and aversion to self-promotion, contribute to his lack of recognition when compared with his contemporaries. The Concert Suite for Violin and Orchestra, composed six years before his death, is his only work for Violin and Orchestra and was his last large composition. This work is cast in an unusual five-movement structure and embodies various brilliant violin techniques and rich Romantic-era harmonies. Taneyev’s interests in “old fashioned” style and folk music are evidenced by some of the movements titled “Prelude,” “Gavotte,” and “Theme and Variation” which contains a double fugue. He also utilizes folk dances such as the mazurka and tarantella. This performance guide provides practical interpretational advice based on an analysis of harmony, form and structural divisions, stylistic considerations and violin techniques. A brilliant and charming work, it has sadly been neglected. Through the study and performance of this piece, the author hopes to provide performers with useful information that enables more musicians to know and enjoy this valuable masterwork. / Dissertation/Thesis / Doctoral Dissertation Music 2019

Tese de mestrado integrado. Engenharia Civil (Estruturas). Universidade do Porto. Faculdade de Engenharia. 2010

The subject of free vibration analysis of thin cylindrical shells is one that extends well back into the last century. In general, the computational methods can be classified as analytical methods and numerical methods. Based on the Flugge thin shell theory, this thesis presents exact solutions for vibration of closed and open cylindrical shells. The state-space technique is adopted to derive the homogenous differential equations for a shell segment and the domain decomposition method is employed to impose the equilibrium and compatability requirements along the interfaces of the shell segments. Extensive analytical and numerical results have been obtained in this thesis for vibration of open/closed cylindrical shells with different boundary conditions, step-wise thickness variations, and multiple intermediate ring supports. The results can serve as useful benchmark values for researchers and engineers to validate their numerical method for shell analysis. / Doctor of Philosophy (PhD)

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

<p>Technical systems of today are often complex and integrated. If a fault occurs, the consequences can be disastrous both for the system itself and its surroundings. To maintain the operation and the security it is necessary to have a surveillance system which can detect a fault in an early stage.</p><p>In this thesis two structural methods for fault isolation analysis are discussed. The result from the studied algorithms shows what fault isolation properties a diagnostic model is expected to have. If the isolability is not good enough, it also gives information on where further modelling needs to be done. </p><p>To base a comparison of the two structural analysis algorithms on, four criteria are defined concerning for example realizability of residuals and time complexity. One interesting part of the methods is how dynamic models are handled. It is shown how differential constraints can end up in differential cycles which implies calculatory problems and what effects structural differentiation has on a system. </p><p>The algorithms have been tested on an application from the research training network DAMADICS. The result shows how different types of input models in this case give the same result.</p>

Thesis (M.C.E.)--University of Delaware, 2006. / Principal faculty advisor: Michael J. Chajes, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Purpose: The objective of this study was to examine the timing of the age and the magnitude of peak lean tissue mass accrual (peak lean tissue velocity, PLTV) as it relates to the age and magnitude of peak cross sectional area velocity (PCSAV) and section modulus velocity (PZV) of proximal femur in both males and females during adolescence. We hypothesized that the age of PLTV would precede the age of PCSAV and PZV and that there be a positive relationship between the magnitude of PLTV and both PCSAV and PZV in both genders. <p>Methods: 41 males and 42 females aged 8-18 years were selected from the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-2005). Participants total body lean tissue mass was assessed annually for 6 consecutive years using DXA. Narrow neck, intertrochanteric and femoral shaft cross sectional areas (CSA) and section modulus (Z) were determined annually using the hip structural analysis (HSA) program. Participants were aligned by maturational age (years from peak height velocity). Lean tissue mass, CSA, and Z were converted into whole year velocities and the maturational age of peak tissue velocities was determined using a cubic spline curve fitting procedure. A 2x3 (gender x tissue) factorial MANOVA with repeated measures was used to test for differences between age of PLTV and both, the age of PCSAV and PZV between males and females. Multiple regression analyses were used to determine the relationship between PLTV and both PCSAV and PZV.<p>Results: There were no sex differences in the ages at which tissue peaks occurred when aligned by maturational age. There were significant differences between the age of PLTV and both PCSAV and PZV at the narrow neck (p=0.001) and femoral shaft (p=0.03), where the age of PLTV preceded both PCSAV and PZV when pooled by gender. There were no significant differences at the intertrochanteric site (p=0.814). PLTV was a significant predictor of the magnitude of both PCSAV and PZV at all sites (p<0.05). <p> Conclusions: These findings support the hypothesis that the age of PLTV precedes the age of PCSA and PZV at the proximal femur and provides further evidence to support the muscle-bone relationship, suggesting that lean tissue mass accrual influences bone strength development at proximal femur during pubertal growth.

The purpose of this work was to develop a practical method for constitutive modelling of polyethylene, based on a phenomenological approach, which can be applied for structural analysis. Polyethylene (PE) is increasingly used as a structural material, for example in pipes installed by trenchless methods where relatively low stiffness of PE reduces the required installation forces, chemical inertness makes it applicable for corrosive environments, and adequate strength allows to use it for sewer, gas and water lines. Polyethylene exhibits time-dependent constitutive behaviour, which is also dependent on the applied stress level resulting in nonlinear stress-strain relationships. Nonlinear viscoelastic theory has been well established and a variety of modelling approaches have been derived from it. In order to be able to realistically utilize the nonlinear modelling approaches in design, a simple method is needed for finding the constitutive formulation for a specific polyethylene type. In this study, time-dependent constitutive relationships for polymers are investigated for polyethylene materials. Creep tests on seven polyethylene materials were conducted and the experimental results indicate strong nonlinear viscoelasticity in the material responses. Creep tests on seven materials were conducted for 24 hours for modelling purposes. However, creep tests up to fourteen days were performed on one material to study long-term creep behaviour. Multiple-stepped creep tests were also investigated. Constant rate (load and strain rate) tensile tests were conducted on two of the seven polyethylene materials. A practical approach to nonlinear viscoelastic modelling utilizing both multi-Kelvin element theory and power law functions to model creep compliance is presented. Creep tests are used to determine material parameters and models are generated for four different polyethylene materials. The corroboration of the models is achieved by comparisons with the results of different tensile creep tests, with one dimensional step loading test results and with test results from load and displacement rate loading.

Technical systems of today are often complex and integrated. If a fault occurs, the consequences can be disastrous both for the system itself and its surroundings. To maintain the operation and the security it is necessary to have a surveillance system which can detect a fault in an early stage. In this thesis two structural methods for fault isolation analysis are discussed. The result from the studied algorithms shows what fault isolation properties a diagnostic model is expected to have. If the isolability is not good enough, it also gives information on where further modelling needs to be done. To base a comparison of the two structural analysis algorithms on, four criteria are defined concerning for example realizability of residuals and time complexity. One interesting part of the methods is how dynamic models are handled. It is shown how differential constraints can end up in differential cycles which implies calculatory problems and what effects structural differentiation has on a system. The algorithms have been tested on an application from the research training network DAMADICS. The result shows how different types of input models in this case give the same result.