Дисертації з теми "Structural and parametric adaptation"
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Gao, Haotian. "POD-Galerkin based ROM for fluid flow with moving boundaries and the model adaptation in parametric space." Diss., Kansas State University, 2018. http://hdl.handle.net/2097/38776.
Повний текст джерелаАнотація:
Doctor of PhilosophyDepartment of Mechanical and Nuclear Engineering
Mingjun Wei
In this study, a global Proper Orthogonal Decomposition (POD)-Galerkin based Reduced Order model (ROM) is proposed. It is extended from usual fixed-domain problems to more general fluid-solid systems with moving boundaries/interfaces. The idea of the extension is similar to the immersed boundary method in numerical simulations which uses embedded forcing terms to represent boundary motions and domain changes. This immersed boundary method allows a globally defined fixed domain including both fluid and solid, where POD-Galerkin projection can be directly applied. However, such a modified approach cannot get away with the unsteadiness of boundary terms which appear as time-dependent coefficients in the new Galerkin model. These coefficients need to be pre-computed for prescribed periodic motion, or worse, to be computed at each time step for non-prescribed (e.g. with fluid-structure interaction) or non-periodic situations. Though computational time for each unsteady coefficient is smaller than the coefficients in a typical Galerkin model, because the associated integration is only in the close neighborhood of moving boundaries. The time cost is still much higher than a typical Galerkin model with constant coefficients. This extra expense for moving-boundary treatment eventually undermines the value of using ROMs. An aggressive approach is to decompose the moving boundary/domain to orthogonal modes and derive another low-order model with fixed coefficients for boundary motion. With this domain decomposition, an approach including two coupled low-order models both with fixed coefficients is proposed. Therefore, the new global ROM with decomposed approach is more efficient. Though the model with the domain decomposition is less accurate at the boundary, it is a fair trade-off for the benefit on saving computational cost. The study further shows, however, that the most time-consuming integration in both approaches, which come from the unsteady motion, has almost negligible impact on the overall dynamics. Dropping these time-consuming terms reduces the computation cost by at least one order while having no obvious effect on model accuracy. Based on this global POD-Galerkin based ROM with forcing term, an improved ROM which can handle the parametric variation of body motions in a certain range is also presented. This study shows that these forcing terms not only represent the moving of the boundary, but also decouple the moving parameters from the computation of model coefficients. The decoupling of control parameters provides the convenience to adapt the model for the prediction on states under variation of control parameters. An improved ROM including a shit mode seems promising in model adaptation for typical problems in a fixed domain. However, the benefit from adding a shit mode to model diminishes when the method is applied to moving-boundary problems. Instead, a combined model, which integrates data from a different set of parameters to generate the POD modes, provides a stable and accurate ROM in a certain range of parametric space for moving-boundary problems. By introducing more data from a different set of parameters, the error of the new model can be further reduced. This shows that the combined model can be trained by introducing more and more information. With the idea of the combined model, the improved global ROM with forcing terms shows impressive capability to predict problems with different unknown moving parameters, and can be used in future parametric control and optimization problems.
2
Normann, James Brian. "Parametric identification of nonlinear structural dynamic systems." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/43294.
Повний текст джерелаАнотація:
The identification of linear structural dynamic systems has been dealt with extensively in past studies. Identification methods for nonlinear structures have also been introduced in previous articles, including procedures based on the method of multiple scales, iterative and noniterative direct methods, and state space mappings. Here, a procedure is introduced for the identification of nonlinear structural dynamic systems which is readily applicable to simple as well as more complex multiple degree of freedom systems. The procedure is based on multiple step integration methods for the solution of differential equations. The multiple step integration procedure and the iterative direct method are applied to a number of nonlinear single degree of freedom examples, and are applied to a simple two degrees of freedom example as well. RMS based noise is added to a simulated measured response in order to monitor the effects of measurement errors on the procedures. The input data is filtered before final processing in the identification algorithms. The multistep algorithm is compared to the iterative direct method on the basis of criteria such as accuracy, ease of use, and numerical efficiency.Master of Science
3
Malladi, Sailaja. "Parametric modeling and analysis of structural bonded joints." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=80.
Повний текст джерелаАнотація:
Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains x, 56 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-53).
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Danhaive, Renaud Aleis Pierre Emile. "Integrating interactive evolutionary exploration and parametric structural design." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99595.
Повний текст джерелаАнотація:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-48).
Current modeling and analysis tools are extremely powerful and allow one to generate and analyze virtually any structural shape. However, most of them do not allow designers to integrate structural performance as an objective during conceptual design. As structural performance is highly linked to architectural geometry, there is a need for computational strategies allowing for performance-oriented structural design in architecture. In order to address these issues, this research combines interactive evolutionary optimization and parametric modeling to develop a new computational strategy for creative and high-performance conceptual structural design. Parametric modeling allows for quick exploration of complex geometries and can be combined with analysis and optimization algorithms for performance-driven design. However, this methodology often questions the designer's authorship as it is based on the use of black-box optimizers. On the other hand, interactive evolutionary optimization empowers the user by acknowledging his or her input as fundamental and includes it in the evolutionary optimization process. This approach aims at improving the structural performance of a concept without limiting the creative freedom of designers. Taking advantage of the two frameworks, this research implements an interactive evolutionary structural optimization framework in the widely used parametric modeling environment constituted by Rhinoceros and Grasshopper. Previous work has illustrated the benefits of combining parametric modeling and genetic algorithms for design space exploration. Comparatively, the implemented design tool capitalizes on Grasshopper's versatility for geometry generation but supplements the visual programming interface with a flexible portal increasing the designer's creative freedom through enhanced interactivity. The tool can accommodate a wide range of structural typologies and geometrical forms in an integrated environment. This research offers a versatile, performance- and user-oriented environment for creative and efficient conceptual structural design.
by Renaud Aleis Pierre Emile Danhaive.
M. Eng.
5
Jones, Garrett P. (Garrett Pierce). "Interoperable software for parametric structural analysis and optimization." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82713.
Повний текст джерелаАнотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis. "June 2013."
Includes bibliographical references (p. 62-64).
The advent of building information modeling in the structural engineering profession has brought forth new challenges to the traditional methods of design and analysis. The need for faster, more robust analyses to mitigate expenses and increase structural insight is a demand that stems from the implementation of BIM modeling. Current software interoperability now allows engineers limited opportunity to engage directly and immediately with the design process. The development of tools which can bring together the architectural and structural engineering professions are of paramount importance in the next phase of professional design. In response to this professional demand, a software framework for Rhino3D modeling software was created which explores the various methods of searching a design space and finding solutions. Both parametric design generation and genetic optimizations were employed, allowing architects and engineers to explore the design space of a structure using metrics important to each field. A case study is performed using the developed software framework to quantify results and validate the effectiveness of such a new design tool in the current engineering profession. The outcome is an improved design experience that is feasible in time and scope, allowing architects and engineers an opportunity to truly explore the design space. Keywords: Parametric modeling and analysis, Genetic optimization, Building information modeling
by Garrett P. Jones.
M.Eng.
6
Stefan, Diana. "Structural and parametric identification of bacterial regulatory networks." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENM019/document.
Повний текст джерелаАнотація:
Les technologies expérimentales à haut débit produisent de grandes quantités de données sur les niveaux d'expression des gènes dans les bactéries à l'état d'équilibre ou lors des transitions de croissance.Un défi important dans l'interprétation biologique de ces données consiste à en déduire la topologie du réseau de régulation ainsi que les fonctions de régulation quantitatives des gènes.Un grand nombre de méthodes d'inférence a été proposé dans la littérature. Ces méthodes ont été utilisées avec succès dans une variété d'applications, bien que plusieurs problèmes persistent.Nous nous intéressons ici à l'amélioration de deux aspects des méthodes d'inférence.Premièrement, les données transcriptomiques reflètent l'abondance de l'ARNm, tandis que, le plus souvent, les composants régulateurs sont les protéines codées par les ARNm.Bien que les concentrations de l'ARNm et de protéines soient raisonnablement corrélées à l'état stationnaire, cette corrélation devient beaucoup moins évidente dans les données temporelles acquises lors des transitions de croissance à cause des demi-vies très différentes des protéines et des ARNm.Deuxièmement, la dynamique de l'expression génique n'est pas uniquement contrôlée par des facteurs de transcription et d'autres régulateurs spécifiques, mais aussi par des effets physiologiques globaux qui modifient l'activité de tous les gènes. Par exemple, les concentrations de l'ARN polymérase (libre) et les concentrations des ribosomes (libres) varient fortement avec le taux de croissance. Nous devons donc tenir compte de ces effets lors de la reconstruction d'un réseau de régulation à partir de données d'expression génique.Nous proposons ici une approche expérimentale et computationnelle combinée pour répondre à ces deux problèmes fondamentaux dans l'inférence de modèles quantitatifs de promoteurs bactériens à partir des données temporelles d'expression génique.Nous nous intéressons au cas où la dynamique de l'expression génique est mesurée in vivo et en temps réel par l'intermédiaire de gènes rapporteurs fluorescents. Notre approche d'inférence de réseaux de régulation tient compte des différences de demi-vie entre l'ARNm et les protéines et prend en compte les effets physiologiques globaux.Lorsque les demi-vies des protéines sont connues, les modèles expérimentaux utilisés pour dériver les activités des gènes à partir de données de fluorescence sont intégrés pour estimer les concentrations des protéines.L'état physiologique global de la cellule est estimé à partir de l'activité d'un promoteur de phage, dont l'expression n'est contrôlée par aucun des facteurs de transcription et ne dépend que de l'activité de la machinerie d'expression génique.Nous appliquons l'approche à un module central dans le réseau de régulation contrôlant la motilité et le système de chimiotactisme chez Escherichia coli.Ce module est composé des gènes FliA, FlgM et tar.FliA est un facteur sigma qui dirige l'ARN polymérase vers les opérons codant pour des composants de l'assemblage des flagelles.Le troisième composant du réseau, tar, code pour la protéine récepteur chimiotactique de l'aspartate, Tar, et est directement transcrit par FliA associé à l' holoenzyme ARN polymérase. Le module FliA-FlgM est particulièrement bien adapté pour l'étude des problèmes d'inférence considérés ici, puisque le réseau a été bien étudié et les démivies des protéines jouent un rôle important dans son fonctionnement.Nos résultats montrent que, pour la reconstruction fiable de réseaux de régulation transcriptionelle chez les bactéries, il est nécessaire d'inclure les effets globaux dans le modèle de réseau et d'en déduire de manière explicite les concentrations des protéines à partir des profils d'expression observés, car la demi-vie de l'ARNm et des protéines sont très différentes. Notre approche reste généralement applicable à une grande variété de problèmes d'inférence de réseaux et nous discutons les limites et les extensions possibles de la méthodeHigh-throughput technologies yield large amounts of data about the steady-state levels and the dynamical changes of gene expression in bacteria. An important challenge for the biological interpretation of these data consists in deducing the topology of the underlying regulatory network as well as quantitative gene regulation functions from such data. A large number of inference methods have been proposed in the literature and have been successful in a variety of applications, although several problems remain. We focus here on improving two aspects of the inference methods. First, transcriptome data reflect the abundance of mRNA, whereas the components that regulate are most often the proteins coded by the mRNAs. Although the concentrations of mRNA and protein correlate reasonably during steady-state growth, this correlation becomes much more tenuous in time-series data acquired during growth transitions in bacteria because of the very different half-lives of proteins and mRNA. Second, the dynamics of gene expression is not only controlled by transcription factors and other specific regulators, but also by global physiological effects that modify the activity of all genes. For example, the concentrations of (free) RNA polymerase and the concentration of ribosomes vary strongly with growth rate. We therefore have to take into account such effects when trying to reconstruct a regulatory network from gene expression data. We propose here a combined experimental and computational approach to address these two fundamental problems in the inference of quantitative models of the activity of bacterial promoters from time-series gene expression data. We focus on the case where the dynamics of gene expression is measured in vivo and in real time by means of fluorescent reporter genes. Our network reconstruction approach accounts for the differences between mRNA and protein half-lives and takes into account global physiological effects. When the half-lives of the proteins are available, the measurement models used for deriving the activities of genes from fluorescence data are integrated to yield estimates of protein concentrations. The global physiological state of the cell is estimated from the activity of a phage promoter, whose expression is not controlled by any transcription factor and depends only on the activity of the transcriptional and translational machinery. We apply the approach to a central module in the regulatory network controlling motility and the chemotaxis system in Escherichia coli. This module comprises the FliA, FlgM and tar genes. FliA is a sigma factor that directs RNA polymerase to operons coding for components of the flagellar assembly. The effect of FliA is counteracted by the antisigma factor FlgM, itself transcribed by FliA. The third component of the network, tar, codes for the aspartate chemoreceptor protein Tar and is directly transcribed by the FliA-containing RNA polymerase holoenzyme. The FliA-FlgM module is particularly well-suited for studying the inference problems considered here, since the network has been well-studied and protein half-lives play an important role in its functioning. We stimulated the FliA-FlgM module in a variety of wild-type and mutant strains and different growth media. The measured transcriptional response of the genes was used to systematically test the information required for the reliable inference of the regulatory interactions and quantitative predictive models of gene regulation. Our results show that for the reliable reconstruction of transcriptional regulatory networks in bacteria it is necessary to include global effects into the network model and explicitly deduce protein concentrations from the observed expression profiles. Our approach should be generally applicable to a large variety of network inference problems and we discuss limitations and possible extensions of the method
7
Saman, Nariman Goran. "A Framework for Secure Structural Adaptation." Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-78658.
Повний текст джерелаАнотація:
A (self-) adaptive system is a system that can dynamically adapt its behavior or structure during execution to "adapt" to changes to its environment or the system itself. From a security standpoint, there has been some research pertaining to (self-) adaptive systems in general but not enough care has been shown towards the adaptation itself. Security of systems can be reasoned about using threat models to discover security issues in the system. Essentially that entails abstracting away details not relevant to the security of the system in order to focus on the important aspects related to security. Threat models often enable us to reason about the security of a system quantitatively using security metrics. The structural adaptation process of a (self-) adaptive system occurs based on a reconfiguration plan, a set of steps to follow from the initial state (configuration) to the final state. Usually, the reconfiguration plan consists of multiple strategies for the structural adaptation process and each strategy consists of several steps steps with each step representing a specific configuration of the (self-) adaptive system. Different reconfiguration strategies have different security levels as each strategy consists of a different sequence configuration with different security levels. To the best of our knowledge, there exist no approaches which aim to guide the reconfiguration process in order to select the most secure available reconfiguration strategy, and the explicit security of the issues associated with the structural reconfiguration process itself has not been studied. In this work, based on an in-depth literature survey, we aim to propose several metrics to measure the security of configurations, reconfiguration strategies and reconfiguration plans based on graph-based threat models. Additionally, we have implemented a prototype to demonstrate our approach and automate the process. Finally, we have evaluated our approach based on a case study of our making. The preliminary results tend to expose certain security issues during the structural adaptation process and exhibit the effectiveness of our proposed metrics.
8
Masendeke, Rugare B. "Parametric study of stiffened steel containment shell structures." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/19019.
Повний текст джерелаАнотація:
Includes bibliographical references. .A FEM-based parametric study is undertaken to investigate the buckling behavior of meridionally and circumferentially stiffened steel cylindrical and conical shell frustum subjected to different load cases. This situation arises in different steel shell applications such as storage vessels (liquid, solid and gas) and in certain configurations of industrial process facilities. The stiffeners are flat strips of rectangular section welded on to the outer surface of the shell, either over the whole length of the shell meridian or around the circumference of the shell. It is required to establish how the elastic buckling load and mode shapes vary with respect to certain key parameters of the problem. The parameters of interest in the study include the number of stiffeners around the shell circumference and along the meridian, the stiffener-depth to shell-thickness ratio, and the stiffener depth-to-width ratio. This thesis reports the findings of the parametric study and also presents some results of experimental tests on laboratory small-scale models of stiffened cylindrical and conical frusta.
9
Sareen, Samita. "Estimation and testing of structural parametric sealed-bid auctions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0026/NQ49879.pdf.
Повний текст джерела
10
Worden, Keith. "Parametric and nonparametric identification of nonlinearity in structural dynamics." Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/1033.
Повний текст джерелаАнотація:
The work described in this thesis is concerned with procedures for the identification of nonlinearity in structural dynamics. It begins with a diagnostic method which uses the Hubert transform for detecting nonlinearity and describes the neccessary conditions for obtaining a valid Hubert transform. The transform is shown to be incapable of producing a model with predictive power. A method based on the identification of nonlinear restoring forces is adopted for extracting a nonlinear model. The method is critically examined; various caveats, modifications and improvements are obtained. The method is demonstrated on time data obtained from computer simulations. It is shown that a parameter estimation approach to restoring force identification based on direct least—squares estimation theory is a fast and accurate procedure. In addition, this approach allows one to obtain the equations of motion for a multi—degree—of—freedom system even if the system is only excited at one point. The data processing methods for the restoring force identification including integration and differentiation of sampled time data are developed and discussed in some detail. A comparitive study is made of several of the most well—known least—squares estimation procedures and the direct least —squares approach is applied to data from several experiments where it is shown to correctly identify nonlinearity in both single— and multi—degree--of—freedom systems. Finally, using both simulated and experimental data, it is shown that the recursive least—squares algorithm modified by the inclusion of a data forgetting factor can be used to identify time—dependent structural parameters.
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Yanik, Yasar. "Quantification of parametric uncertainties effects in structural failure criteria /." Ilha Solteira, 2019. http://hdl.handle.net/11449/182040.
Повний текст джерелаАнотація:
Orientador: Samuel SilvaResumo: Critérios de falhas realizam a predição de circunstâncias nas quais materiais sólidos estão sobre ação de carregamentos externos. As teorias de falhas são conhecidas como diferentes critérios de falhas, como von Mises e Tresca, os quais são os mais famosos para determinados materiais. Além disso, esta dissertação de mestrado pretende mostrar a comparação entre os critérios de falha de Tresca e von Mises, levando em conta incertezas subjacentes nas equações constitutivas e na análise de tensão. Para exemplificar acomparação,algumassimulaçõessãorealizadasusandoumaplacasimples,umproblema de deflexão simples,e a estrutura de um carro do formula SAE. Devido à complexidade deste sistema, diferentes tipos de etapas probabilísticas são utilizadas, como o método de superfície de resposta e a correlação de parâmetros. Os resultados mostram que várias variáveis aleatórias de entrada afetam em maneiras diferentes as variáveis aleatórias de saída e que não há uma diferença grande entre os critérios de falha de von Mises e Tresca quando incertezas são assumidas na formulação para a análise de tensão.
Abstract: Failure theory is the investigation of predicting circumstances under which solid materials under the processing of external loads. The theories of failure are known as different failure criteria such as von Mises and Tresca which are the most famous of these for certain materials. Additionally, this master dissertation intends to show a comparison between Tresca and von Mises failure criterions, taking into account the underlying uncertainties in the constitutive equations and stress analysis. In order to exemplify the comparison, some numerical simulations are performed using a simple plate, simple deflection problem and a frame of the formula car. Due to the complexity of frame of the formula car, different kind of probabilistic steps are used as a response surface method and parameters correlation. Results show that several random input variables effect the random output variables in various ways, and there is no such a big difference between the von Mises and Tresca failure criterions when uncertainties are assumed in the formulation for stress analysis.
Mestre
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Anderson, Matthew Francis. "Parametric investigation of strain gauges in structural damage detection." Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/2436.
Повний текст джерелаАнотація:
Vibration-based damage detection (VBDD) methods are used to detect damage in structural members non-evasively. This investigation began with two objectives: to prove a VBDD method could detect damage using strain gauges both analytically and experimentally, and to then use that method to determine the distance from a damaged area that strain gauges could be effective. Work began simultaneously using finite element software and physical experiments. It was determined that a VBDD method could detect damage with strain gauges in both settings. A parametric study was then completed that used probabilistic methods to identify an effective range for strain gauges over the length of the structural member.
13
Seckiner, Soner. "Parametric Analysis Of Inelastic Interaction In Frame-wall Structural Systems." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613654/index.pdf.
Повний текст джерелаАнотація:
The purpose of this thesis is to investigate the inelastic action in the reinforced concrete frame-wall structures analytically and with that analysis to follow the plastic formation of the structure. For this purpose, six mid-rise reinforced concrete buildings with frame-wall are modeled and analyzed to understand the effect of the height and base shear force ratio of the wall on the nonlinear interaction between reinforced concrete wall and frame members under static lateral loads and ground motion excitations. The parametric analysis is conducted by assuming planar response of the buildings under loadings.
The buildings are generated considering the limit design concept suggested by Turkish Earthquake Code 2007 and Turkish Standards TS500, and the frame-wall members are modeled by using spread plasticity elements and fiber discretization of sections. In the analysis stage, each element section is divided into confined and unconfined regions for detailed modeling of the building by using OpenSEES nonlinear finite element program. Two dimensional analyses are conducted under static and dynamic loadings. For static pushover analyses, three different lateral load cases (Triangular, Uniform and First-Mode Lateral Load Patterns) are considered. For dynamic analyses, eight different ground motions are used. These ground motions are scaled to the corresponding design response spectrum suggested by Turkish Earthquake Code 2007 by using RSPMATCH program. Using the result of the complex and simplified analyses, inter-story drift ratios, plastic rotations and internal force distributions of the buildings are investigated.
14
Gentry, Jeanette J. "Nonlinear oscillations under multifrequency parametric excitation." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43402.
Повний текст джерелаАнотація:
A second-order system of differential equations containing a multifrequency parametric excitation and weak quadratic and cubic nonlinearities is investigated. The method of multiple scales is used to carry out a general analysis, and three resonance conditions are considered in detail. First, the case in which the sum of two excitation frequencies is near two times a natural frequency, λs + λt ~2Ï q, is examined. Second, the influence of an internal resonance, Ï q~3Ï r, on the previous case is studied. Finally, the effect of the internal resonance wr~3wq on the resonance λs + λt ~2Ï q is investigated. Results are presented as plots of response amplitudes as functions of a detuning parameter, excitation amplitude, and, for the first case, a measure of the relative values of λs + λt.
Master of Science
15
Pentaris, Fragkiskos. "Digital signal processing for structural health monitoring of buildings." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/10560.
Повний текст джерелаАнотація:
Structural health monitoring (SHM) systems is a relatively new discipline, studying the structural condition of buildings and other constructions. Current SHM systems are either wired or wireless, with a relatively high cost and low accuracy. This thesis exploits a blend of digital signal processing methodologies, for structural health monitoring (SHM) and develops a wireless SHM system in order to provide a low cost implementation yet reliable and robust. Existing technologies of wired and wireless sensor network platforms with high sensitivity accelerometers are combined, in order to create a system for monitoring the structural characteristics of buildings very economically and functionally, so that it can be easily implemented at low cost in buildings. Well-known and established statistical time series methods are applied to SHM data collected from real concrete structures subjected to earthquake excitation and their strong and weak points are investigated. The necessity to combine parametric and non-parametric approaches is justified and to this direction novel and improved digital signal processing techniques and indexes are applied to vibration data recordings, in order to eliminate noise and reveal structural properties and characteristics of the buildings under study, that deteriorate due to environmental, seismic or anthropogenic impact. A characteristic and potential harming specific case study is presented, where consequences to structures due to a strong earthquake of magnitude 6.4 M are investigated. Furthermore, is introduced a seismic influence profile of the buildings under study related to the seismic sources that exist in the broad region of study.
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Basile, Franklin C. "Parametric shape generation of aerodynamic and structural objects for aerodynamic, structural and radar cross-section analysis." Master's thesis, University of Central Florida, 1988. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/79106.
Повний текст джерелаАнотація:
University of Central Florida College of Engineering ThesisThis thesis describes the design and development of software to parametrically build three-dimensional aerodynamic objects or shapes for various engineering design and analysis activities. The software is designed to generate and display sufficient geometric output to completely define the object. Parameters are entered through a prompting sequence which determines the type of object and the amount of geometry needed to describe the object. Geometry created by this program will act as the baseline model for aerodynamic , structural, and radar cross-section analysis. An integral part of the program is the complete 3-D viewing capability. Interactive global display capability allows for visualization of the model from any direction. Input of a viewing direction or an eye-point position will automatically shift the viewer to the correct orientation in space while scaling and centering the model on teh display. Once the object geometry has been verified and accepted, it is converted to a surface model by a second program developed at the Martin Marietta Orlando Aerospace Company, and formatted for input into aerodynamic analysis programs such as S-HABP (Supersonic-Hypersonic Arbitary Body Program) for lift and drag calcuations at multiple angles of attack and trim conditions and/or CAMS (Computer Aided Missile Synthesis) for trajectory data calculations under various flight regimes. The geometry may also be formatted for input to the stress and dynamic mode analysis program NASTRAN or the physical optics scattering program POSCAT which is used to predict radar signal returns of an object at any desired frequency. Program design, geometry generation, and data manipulation techniques are presented in detail.
M.S.
Masters
Engineering
Engineering
182 p.
viii, 182 leaves, bound : ill. ; 28 cm.
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Lagergren, Maria. "Parametric model for structural stability computation of chassis in tipper trailers." Thesis, KTH, Hållfasthetslära (Inst.), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92642.
Повний текст джерелаАнотація:
When a tipper trailer empties the load it carries, a torque occurs if the trailer stands on uneven ground. To withstand this torque, and prevent the trailer to roll over, the chassis‟ torsional stiffness must be high enough. The stiffness is highly dependent of the geometry of the chassis structure. When analysing different geometries the pre-processing of the finite element (FE)-model is time consuming. The first part in this master thesis was to assess what element type to use for this type of load case. It was necessary to simplify the FE-model as much as possible for the second part of the thesis. A comparison of modelling the chassis with beam elements instead of shell elements was performed. It was concluded that resultant beam elements should be used when analysing the torsional stiffness of the chassis. In the second part of this master thesis a program was developed to automate the FE-modelling of the chassis, this to be able to compare several chassis structures in a short amount of time. The program generates a FE-model of the desired chassis structure depending on parameters given from the user. The program produces a text file, containing information about the FE-model, which can be read and viewed in a LS-DYNA compatible pre-processor.
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Pajkert, Anna Ewa. "Behavioural and Structural Adaptation to Hippocampal Dysfunction in Humans." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21757.
Повний текст джерелаАнотація:
Die flexible Anwendung von Wissen in neuen Alltagssituationen ist eine notwendige kognitive Fähigkeit. Bisherige Studien betonen die zentrale Rolle des Hippocampus beim Lernen und Verknüpfen neuer Informationen mit bereits vorhandenem Wissen. Die funktionelle Integrität des Hippocampus ändert sich jedoch im Laufe des Lebens bzw. wird durch neuropsychiatrische Erkrankungen häufig beeinflusst. Die betroffenen Personen müssen deswegen adaptive Strategien entwickeln, um behaviorale Ziele weiter zu erreichen.
Daher befasst sich meine Doktorarbeit mit Adaptationsprozessen im sich entwickelnden Gehirn und im vollständig entwickelten Gehirn mit einer hippocampalen Dysfunktion. Diese Synopsis umfasst dazu drei Studien: (1) zu behavioralen Strategien im sich entwickelnden Gehirn, (2) zu behavioralen Strategien im vollständig entwickelten Gehirn nach einer Läsion und (3) zu strukturellen Veränderungen im vollständig entwickelten Gehirn nach einer Läsion.
Studie 1 zeigt einen altersgebundenen Wechsel beim assoziativen Gedächtnis: Kinder, Jugendliche und junge Erwachsene benutzen verschiedene Gedächtnisstrategien beim Integrieren von Gedächtnisinhalten.
Studie 2 zeigt, dass die beobachteten Gedächtnisbeeinträchtigungen bei Patienten mit rechtsseitigen hippocampalen Läsionen sich nicht alleine durch ein Defizit des assoziativen Gedächtnisses erklären lassen, sondern auf einen zusätzlichen hippocampalen Beitrag zur Gedächtnisintegration zurückzuführen sind.
Studie 3 zeigt, dass sich postoperative Adaptationsprozesse auf struktureller Ebene in überraschend kurzer Zeit ereignen und dass die strukturelle Reorganisation nicht nur im Hippocampus, sondern auch in entfernteren Hirnregionen, die mit dem Hippocampus verbunden sind, stattfindet.
Zusammenfassend zeigen die Ergebnisse der drei Studien, dass Adaptationsprozesse im sich entwickelnden Gehirn sowie bei Erwachsenen mit einer hippocampalen Dysfunktion sowohl auf der behavioralen als auch auf der strukturellen Ebene auftreten.Applying knowledge flexibly to new situations is a cognitive faculty that is necessary in every-day life. Previous findings emphasise the crucial role the hippocampus plays in learning and linking new information with pre-existing knowledge. However, the functional integrity of the hippocampus changes over the lifespan and is frequently affected by neuropsychiatric disorders. The affected subjects must, therefore, develop adaptive strategies to achieve behavioural goals. Thus, my doctoral thesis deals with adaptation processes in the developing brain and in adult brains with a hippocampal dysfunction. This synopsis encompasses three studies on: (1) behavioural strategies in the developing brain, (2) behavioural strategies in the lesioned fully developed brain, and (3) structural changes in the lesioned fully developed brain. Study 1 suggests an age-related shift in the associative memory: Children, adolescents, and young adults use different memory strategies when integrating information. Study 2 suggests that the memory deficits observed in patients with right-sided hippocampal lesions are not merely a consequence of an impaired associative memory but rather result from an additional hippocampal contribution to the memory integration. Study 3 suggests that postoperative structural adaptation processes occur on a surprisingly short time-scale, and this structural reorganisation happens not only in the hippocampus but also in distant brain areas connected to the hippocampus. In conclusion, findings from these three studies show that adaptation processes in the developing brain and in adult brains with hippocampal dysfunction occur on both the behavioural and the structural level.
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Govender, Nishalin. "A parametric investigation into the membrane stresses of hydrostatically loaded circular and elliptic toroidal shells." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25284.
Повний текст джерелаАнотація:
This study explores the membrane stresses of hydrostatically loaded elliptical and circular toroidal tanks. Equations are derived, using the membrane theory of shells, to obtain equations which can accurately describe the meridional and hoop stress behaviour at locations sufficiently far away from any bending disturbance occurring within the shell. The derived expressions are validated using the finite element software ADINA, indicating excellent agreement between the analytical and numerical solutions. A parametric study is undertaken, whereby the membrane profiles for prolate, oblate and circular toroidal shells is investigated. Parameters which are varied are the opening and aspect ratio of toroidal shells. Stress resultant profiles are shown for numerous cases in order to aid designers on suitable ratios to minimise membrane stresses for use when designing hydrostatically loaded toroidal shells. Lastly, numerical examples are investigated, keeping the volume constant and comparing the surface area due to a variation of opening and aspect ratios. It was found that when investigating toroidal shells, considerations are required when choosing the aspect ratio and opening ratios. Based on the results obtained, compromises between prolate and circular cross-sections with relatively small opening ratios are recommended in order to minimise the cost and maximise the structural efficiency, based on the membrane stresses occurring within the shell.
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Gruionu, Gabriel. "Structural adaptation of arcade arteries to changes in blood flow." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280607.
Повний текст джерелаАнотація:
Arcades are blood vessels that form direct connections between two arteries or arterioles. Because they are supplied with blood from two sources, arcades can function as alternative flow pathways following obstruction of arteries or arterioles, as in coronary and peripheral vascular disease and stroke. In response to changes in blood flow or metabolic conditions, vascular networks undergo structural adaptation or remodeling, which includes structural changes of the existing vessels and growth of new vessels. Following obstruction of a blood supply, arcade vessels may adjust their internal diameters chronically to convert the alternative pathways into main blood distribution vessels. The overall goal of this dissertation was to examine structural changes in the internal diameter of a single arcade artery and the arterioles of an arcade network following changes in blood flow, using experimental and theoretical approaches. Diameter changes of the mouse gracilis arcade artery were observed up to 56 days following resection of one of its two blood supplies. Overall, diameters increased to a maximum around day 21 and then declined. The diameter changes were spatially non-uniform, being largest towards the point of resection, providing transiently increased perfusion to the most affected regions. Observed diameter changes were compared with predictions of a theoretical model, in which diameter varies in response to stimuli derived from local metabolic and hemodynamic conditions. Good agreement was found when effects of a time-delayed growth stimulus in regions of reduced perfusion were included, with a delay of about 7 days. The effectiveness of arcades in maintaining perfusion both immediately following obstruction and after structural adaptation in the arteriolar arcade network between two feed artery branches of the pig triceps brachii muscle was examined. Morphometric data from vascular casting and published data were used to develop a computational model for the hemodynamics and structural adaptation of the network in response to local stimuli. The results show that the arcades provide alternative flow pathways to the region initially supplied by the obstructed branch and that structural adaptation can lead to improved flow restoration following interruption of blood flow.
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Wallin, Daniel, and Martin Wasberg. "Parametric design of building structures in cooperation with architects : Usage and evaluation of structural plug-ins in 3D visualisation software." Thesis, KTH, Betongbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-188948.
Повний текст джерелаАнотація:
Architectural and structural design process are closely connected but traditionally done in twoseparate steps in the design process. This requires effective coordination between the two disciplinesand without the right tools problems often arise.The thesis was done by support from structural engineers at Tyréns and in collaboration with astudent from the department of architecture. The aim of the thesis was to investigate if the use ofparametric design tools from both architects and structural engineers could be a way of making thedesign process more effective. This thesis also include test the structural plug-ins of the parametricdesign tools and compare them with the outputs from traditional structural software and handcalculations.The comparison was made for different cases followed by a collaboration project. The cases wastargeting different structural features which in turn gave the knowledge needed to develop thecollaboration project.The case studies consists of five cases where the first two gives an introduction to parametricmodelling. The third case is a steel beam with fully restrained supports loaded by two pointloads. It will compare the displacement calculations between the different software. The next caseis a concrete slab with different supports along edges loaded by a uniformly load. The analysisincludes calculation and evaluation of section forces. The final case is a concrete dome. It is builtup by arches and five supports. The analysis of this case includes calculation and evaluation of thedisplacement.The collaboration project is a concrete structure built up by a curved surface lifted by curvedcolumns. The architect worked with the structure in parallel to this this thesis and targeted thedevelopment process whilst the authors targeted the structural parts and at the same time gavestructural insight to the architect.The results show a difference between the parametric structural tools and the traditional FEsoftware regarding deformation and moments. The hand calculations in the collaboration projectshow that the amount of reinforcement will not work with the given inputs and assumptions dueto practical reasons regarding spacing.The possibility to export models from the parametric environment to traditional engineering software’senables a faster analysis, since the modelling capabilities is limited and time-consumingin these. The structural capabilities of the parametric tools are good enough for deciding initialgeometry and properties but these will probably change when subjected to an more extensiveanalysis.
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Martinez-Sanchis, Elena. "Essays on identification and estimation of structural parametric and semiparametric models in microeconomics." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444804/.
Повний текст джерелаАнотація:
This thesis focuses on identification and estimation of structural parametric and semi-parametric models in microeconometrics. The analysis of the conditions under which in the context of an econometric model-data can be informative about the parameters of interest of an economic process is essential and must be of high priority in any econometric work. When considering models with which to identify interesting features, emphasis should be placed on imposing the minimum set of restrictions in order to achieve identification, since inappropriate restrictions may lead to inconsistent estimates of the parameters of interest. For this reason in the literature one finds that some attention has been paid to relaxing parametric distributional assumptions on the unobservables or functional forms of the relationships between observables and unobservables. To begin with, I examine how the parameters of interest of a general class of models can be identified and then estimated when not all of the relevant variables are jointly observed in the same dataset. To do so, the existence of an additional data set with information on both the missing variables and on some common variables in the original data set is necessary. I then move on to an analysis of the identification of the preference parameters in a discrete choice demand model in which individuals only derive utility from the characteristics of the goods they consume. I discuss how this particular model makes the estimation of these parameters feasible without imposing distributional assumptions in the errors even if the number of goods in the choice set is very large. Finally, I consider the comparison of nonparametric regression curves between different samples. I propose to estimate the parameters that explain these differences between the conditional mean functions by using an estimator developed in the semiparametric literature which avoids the computational problems faced by the previously proposed estimators.
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Stinton, Graham William. "Structural studies into AM(_2)O(_7) framework materials and parametric Rietveld refinement." Thesis, Durham University, 2006. http://etheses.dur.ac.uk/2436/.
Повний текст джерелаАнотація:
This thesis investigates the structural properties of the AM2O7 family of materials, many of which show interesting thermal expansion properties and remarkably complex structures. It also develops Parametric Rietveld refinement, a method of extracting more information from multi-condition powder diffraction data. Chapter 1 reviews the relevant literature. Chapter 2 describes the equipment and analytic techniques used in the work. Chapter 3 describes Parametric Rietveld refinement, which aims to fit a single, evolving structural model to a series of diffraction data collected as a function of time, temperature, pressure or other external variable. This can lead to a number of benefits over conventional, sequential Rietveld refinement: it can increase the precision of refined parameters; allow physically realistic models to be applied during data analysis; and allow 'non-crystallographic’ quantities, such as temperature or rate constants, to be refined directly from diffraction data. Chapter 4 presents a full structure solution of ZrP(_2)O(_7) at room temperature from powder diffraction data. This involved developing a method for combining Rietveld refinement, restraints and simulated annealing. Despite 136 unique atoms and close-to metrically cubic symmetry, the true structure of this orthorhombic material can be refined to a high degree of precision. Chapter 5 is an investigation into the structures and thermal expansion of two AM(_2)O(_7) species, pseudo-cubic SnP(_2)O(_7) and GeP(_2)o(_7). A full structure solution of the room temperature phase of SnP(_2)O(_7) is presented. Two higher temperature phases of SnP(_2)O(_7) and the low temperature phase of GeP(_2)o(_7) are also analysed. Variable temperature data for both materials are presented. Chapter 6 describes the synthesis and characterisation via powder diffraction of solid-state solutions of the general formula Zr(_x)Sn(_1-x)P(_2)o(_7). The variation of properties across the series is investigated both at room temperature and upon heating.
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Wang, Lyang Suan. "Automating Parametric Redesign of Structural Thin-Walled Frames Based On Topology Optimized Structure." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu156618342438725.
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Eranki, Venkata Krishna Prashanth, and Gurudu Rishank Reddy. "Design and Structural Analysis of a Robotic Arm." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13834.
Повний текст джерелаАнотація:
Automation is creating revolution in the present industrial sector, as it reduces manpower and time of production. Our project mainly deals around the shearing operation, were the sheet is picked manually and placed on the belt for shearing which involves risk factor. Our challenge is designing of pick and place operator to carry the sheet from the stack and place it in the shearing machine for the feeding. We have gone through different research papers, articles and had observed the advanced technologies used in other industries for the similar operation. After related study we have achieved the design of a 3-jointed robotic arm were the base is fixed and the remaining joints move in vertical and horizontal directions. The end effector is also designed such that to lift the sheet we use suction cups were the sheet is uplifted with a certain pressure. Here we used Creo-Parametric for design and Autodesk-Inventor 2017 to simulate the designed model.
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Mokhuthu, Batho. "Parametric study on the buckling behaviour of singly and doubly curved concrete arch dams." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11421.
Повний текст джерелаАнотація:
This study explores the buckling behaviour of thin walled and curved concrete arch dams investigated as a function of various parameters of interest, the focus being on the influence of dam thickness on the elastic buckling behaviour.
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Sweeney, Blake Alexander. "Development of a System for Studying Temperature Adaptation of Structural RNAS." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1321542150.
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Oueini, Shafic Sami. "Techniques for Controlling Structural Vibrations." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/27176.
Повний текст джерелаАнотація:
We tackle the problem of suppressing high-amplitude vibrations of cantilever beams when subjected to either primary external or principal parametric resonances. Guided by results of previous investigations into the nonlinear dynamics of single- and multi-degree-of-freedom structures, we design mechatronic systems of sensors, actuators, and electronic devices and implement nonlinear active feedback control.
In the case of external excitation, we devise two vibration absorbers based on either quadratic or cubic feedback. We conduct theoretical analyses and demonstrate that when a two-to-one (one-to-one) internal resonance condition is imposed between the plant and the quadratic (cubic) absorber, there exists a saturation phenomenon. When the plant is forced near its resonant frequency and the forcing amplitude exceeds a certain small threshold, the nonlinear coupling creates an energy-transfer mechanism that limits (saturates) the response of the plant.
Our theoretical studies reveal that the cubic absorber creates regimes of high-amplitude quasiperiodic and chaotic responses, thereby limiting its utility. However, we show that superior results can be achieved when the natural frequency of the quadratic absorber is set equal to one-half the excitation frequency. Consequently, we apply the quadratic technique through a variety of linear and nonlinear actuators, sensors, and electronic devices.
We design and build second-order analog circuits that emulate the quadratic absorber. Using a DC motor, piezoelectric ceramics, and Terfenol-D struts as actuators and potentiometers, strain gages, and accelerometers as sensors, we demonstrate successful single- and multi-mode vibration control.
In order to realize a more versatile implementation of the control strategy, we resort to a digital signal processing (DSP) board. We compose a code in C and design a digital absorber by developing algorithms that, in addition to replacing the analog circuit, automatically detect the amplitude and frequency of oscillation of the plant and fine-tune the absorber parameters.
We take advantage of the digital realization, implement a linear absorber, and compare the performance of the quadratic absorber with that of its linear counterpart.
In the case of parametric excitation, we investigate two techniques. First, we explore application of the quadratic absorber. We prove theoretically and demonstrate experimentally that this control scheme is not reliable. Then, we propose an alternate approach. We devise a control law based on cubic velocity feedback. We conduct theoretical and experimental investigations and show that the latter strategy leads to effective vibration suppression and bifurcation control.Ph. D.
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Lanzas, Lourdes Eneida 1962. "A parametric study on the behavior of slender reinforced concrete frames." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276945.
Повний текст джерелаАнотація:
By using a nonlinear computer analysis, a parametric study is developed in order to examine the accuracy of the Moment Magnifier Method of the American Concrete Institute Code (ACI 318-83). The variables used in the parametric study are: axial load intensity, P/Po; column reinforcement ratio, rho; slenderness ratio, klu; shape of column cross section, flexural stiffness ratio, and distribution of axial loads. In the parametric study, 216 cases of single bay fixed-base portal frames are examined. The higher moment for each one of these frames at failure are then compared with the design moment predicted by the Moment Magnifier Method of the American Concrete Institute Code (ACI 318-83). The Moment Magnifier Method proved to be very conservative when the columns are subjected to high level of axial loads and when the slenderness ratio is increased.
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Kahn, Sergey. "Thinking Outside The Grid: Structural Design Through Multi-parametric Growth and Self-Adaptive Analysis." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1491317566570458.
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Bondarchuk, M. S., and М. С. Бондарчук. "The use of parametric principles in the elements of park architecture." Thesis, Національний авіаційний університет, 2020. http://er.nau.edu.ua/handle/NAU/42093.
Повний текст джерелаАнотація:
1. Добрицына И.А. От постмодернизма – к нелинейной архитектуре: Архитектура в контексте современной философии и науки / И.А. Добрицына. – М.: Прогресс-Традиция, 2004. – 416 с.
2. Schumacher P. LECTURES & INTERVIEWS – theorizing architecture [Електронний ресурс] / Patrik Schumacher – Режим доступу: http://www.patrikschumacher.com/index.htmThe beginning of XXI century is marked by the emergence of research, experimentation and implementation in the direction of “paramentric”. Parametric principles have been applied in the design of architectural elements of the park. Based on the research, we can conclude that in the design of parks the direction of parametricism is a really new avant-garde style. It largely relies on the structural, constructive and formative principles of nature, thereby continuing to develop the organic approach to a new level. The main feature of parametricism is the appeal to nonlinear forms, which brings it closer to bionic architecture. Thus, this new style is a natural step in the development of modern park architecture and integrates its achievement in the formation, relying on new design technologies and newest construction technologies.
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Pajkert, Anna Ewa [Verfasser]. "Behavioural and Structural Adaptation to Hippocampal Dysfunction in Humans / Anna Ewa Pajkert." Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/1217249877/34.
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Ugail, Hassan. "Parametric design and optimisation of thin-walled structures for food packaging." Springer, 2003. http://hdl.handle.net/10454/2647.
Повний текст джерелаАнотація:
In this paper the parametric design and functional optimisation of thin-walled structures made from plastics for food packaging is considered. These objects are produced in such vast numbers each year that one important task in the design of these objects is to minimise the amount of plastic used, subject to functional constraints, to reduce the costs of production and to conserve raw materials. By means of performing an automated optimisation on the possible shapes of the food containers, where the geometry is parametrised succinctly, a strategy to create the optimal design of the containers subject to a given set of functional constraints is demonstrated.
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Gstach, Dieter. "Comparing Structural Efficiency of Unbalanced Subsamples: A Resampling Adaptation of Data Envelopment Analysis." Inst. für Volkswirtschaftstheorie und -politik, WU Vienna University of Economics and Business, 1993. http://epub.wu.ac.at/6299/1/WP_24.pdf.
Повний текст джерелаАнотація:
At a general level the question is adressed, how to compare structural efficiencies for subgroups in the framework of data envelopment analysis. If a multiproduct technology is
employed in estimating the production possibility frontier and if the subgroups are distinguished by products, then specific problems arise. It is illustrated by Monte-Carlo
techniques that there may be considerable bias in relative structural efficiencies due to unbalanced numbers of observations for different subgroups. A resampling procedure is shown to outperform the simple estimators from data envelopment analysis in such circumstances. The method proposed is applied to austrian farming data to derive
conclusions about the relationship between certain specialization patterns and efficiency.Series: Department of Economics Working Paper Series
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Li, Wei. "Nonlinear effects in ground motion simulations: modeling variability, parametric uncertainty and implications in structural performance predictions." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34658.
Повний текст джерелаАнотація:
While site effects are accounted for in most modern U.S. seismic design codes for building structures, there exist no standardized procedures for the computationally efficient integration of nonlinear ground response analyses in broadband ground motion simulations. In turn, the lack of a unified methodology affects the prediction accuracy of site-specific ground motion intensity measures, the evaluation of site amplification factors when broadband simulations are used for the development of hybrid attenuation relations and the estimation of inelastic structural performance when strong motion records are used as input in aseismic structural design procedures.
In this study, a set of criteria is established, which quantifies how strong nonlinear effects are anticipated to manifest at a site by investigating the empirical relation between nonlinear soil response, soil properties, and ground motion characteristics. More specifically, the modeling variability and parametric uncertainty of nonlinear soil response predictions are studied, along with the uncertainty propagation of site response analyses to the estimation of inelastic structural performance. Due to the scarcity of design level ground motion recording, the geotechnical information at 24 downhole arrays is used and the profiles are subjected to broadband ground motion synthetics.
For the modeling variability study, the site response models are validated against available downhole array observations. The site and ground motion parameters that govern the intensity of nonlinear effects are next identified, and an empirical relationship is established, which may be used to estimate to a first approximation the error introduced in ground motion predictions if nonlinear effects are not accounted for.
The soil parameter uncertainty in site response predictions is next evaluated as a function of the same measures of soil properties and ground motion characteristics. It is shown that the effects of nonlinear soil property uncertainties on the ground-motion variability strongly depend on the seismic motion intensity, and this dependency is more pronounced for soft soil profiles. By contrast, the effects of velocity profile uncertainties are less intensity dependent and more sensitive to the velocity impedance in the near surface that governs the maximum site amplification.
Finally, a series of bilinear single degree of freedom oscillators are subjected to the synthetic ground motions computed using the alternative soil models, and evaluate the consequent variability in structural response. Results show high bias and uncertainty of the inelastic structural displacement ratio predicted using the linear site response model for periods close to the fundamental period of the soil profile. The amount of bias and the period range where the structural performance uncertainty manifests are shown to be a function of both input motion and site parameters.
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Laughlin, Trevor William. "A parametric and physics-based approach to structural weight estimation of the hybrid wing body aircraft." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45829.
Повний текст джерелаАнотація:
Estimating the structural weight of a Hybrid Wing Body (HWB) aircraft during conceptual design has proven to be a significant challenge due to its unconventional configuration. Aircraft structural weight estimation is critical during the early phases of design because inaccurate estimations could result in costly design changes or jeopardize the mission requirements and thus degrade the concept's overall viability. The tools and methods typically employed for this task are inadequate since they are derived from historical data generated by decades of tube-and-wing style construction. In addition to the limited applicability of these empirical models, the conceptual design phase requires that any new tools and methods be flexible enough to enable design space exploration without consuming a significant amount of time and computational resources. This thesis addresses these challenges by developing a parametric and physics-based modeling and simulation (M&S) environment for the purpose of HWB structural weight estimation. The tools in the M&S environment are selected based on their ability to represent the unique HWB geometry and model the physical phenomena present in the centerbody section. The new M&S environment is used to identify key design parameters that significantly contribute to the variability of the HWB centerbody structural weight and also used to generate surrogate models. These surrogate models can augment traditional aircraft sizing routines and provide improved structural weight estimations.
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Moschetti, Lorenzo. "Parametric Sensitivity Study of Shear-Flexure Interaction Modeling for Reinforced Concrete Structural Walls under Cyclic Loading." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Знайти повний текст джерелаАнотація:
In order to predict the inelastic hysteretic behavior of reinforced concrete (RC) structural walls under lateral cyclic loading, robust and reliable numerical tools are required. The Shear-Flexure-Interaction Multiple-Vertical-Line-Element-Model (SFI-MVLEM) proposed by Kolozvari et al. (2015) incorporates important material characteristics and behavioral response features, therefore it promises excellent capabilities. In reference to the SFI-MVLEM approach, this study investigates the global response (i.e. lateral load versus lateral top displacement) sensitivity to some input parameters, in order to evaluate which input parameters are influential and which ones are not. Seven RC structural wall specimens with a moderate aspect ratio are considered for the parametric sensitivity study. The predicted load-displacement responses are compared with the experimental ones, in order to assess variations in analytical responses. The input parameters here analyzed are the number of SFI-MVLEM elements used for the wall discretization, the concrete tensile strength, the dowel stiffness coefficient for steel reinforcing bars, and the cracks closure mechanism.
The study shows that the number of SFI-MVLEM elements does not affect the predicted global response, while the concrete tensile strength and the dowel stiffness coefficient for steel reinforcing bars affect the simulated global response in terms of both lateral load capacity and energy capacity dissipation. In addition, the study indicates that the assumption of sudden crack closure provides more accurate results in terms of energy capacity dissipation than the assumption of gradual cracks closure.
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Miller, Robert. "Approaches to the parametric modeling of hormone concentrations." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-118882.
Повний текст джерелаАнотація:
Transdisciplinary research in general, and stress research in particular, requires an efficient integration of methodological knowledge of all involved academic disciplines, in order to obtain conclusions of incremental value about the investigated constructs. From a psychologist’s point of view, biochemistry and quantitative neuroendocrinology are of particular importance for the investigation of endocrine stress systems (i.e., the HPA axis, and the SNS). Despite of their fundamental role for the adequate assessment of endocrine activity, both topics are rarely covered by conventional psychological curriculae. Consequently, the transfer of the respective knowledge has to rely on other, less efficient channels of scientific exchange. The present thesis sets out to contribute to this exchange, by highlighting methodological issues that are repeatedly encountered in research on stress-related endocrine activity, and providing solutions to these issues.
As outlined within this thesis, modern stress research tends to fall short of an adequate quantification of the kinetics and dynamics of bioactive cortisol. Cortisol has gained considerable popularity during the last decades, as its bioactive fraction is supposed to be reliably determinable from saliva and is therefore the most conveniently obtainable marker of HPA activity. However, a substantial fraction of salivary cortisol is metabolized to its inactivated form cortisone by the enzyme 11β-HSD2 in the parotid glands, which is likely to restrict its utility. Although the commonly used antibody-based quantification methods (i.e. immunoassays) might “involuntarily” qualify this issue to some degree (due to their inherent cross-reactivity with matrix components that are structurally-related to cortisol; e.g., cortisone), they also cause differential within-immunoassay measurement bias: Salivary cortisone has (as compared to salivary cortisol) a substantially longer half-life, which leads to an overestimation of cortisol levels the more time has passed since the onset of the prior HPA secretory episode, and thus tends to distort any inference on the kinetics of bioactive cortisol. Furthermore, absolute cortisol levels also depend on the between-immunoassay variation of antibodies. Consequently, raw signal comparisons between laboratories and studies, which are favorable as compared to effect comparisons, can hardly be performed. This finding also highlights the need for the long-sought standardization of biochemical measurement procedures. The presumably only way to circumvent both issues is to rely on quantification of ultrafiltrated blood cortisol by mass-spectrometric methods.
Being partly related to biochemical considerations with research on HPA activity, a second topic arises concerning the operationalization of the construct itself: In contrast to the simple outcome measures like averaged reaction times, inclined stress researchers can only indirectly infer on the sub-processes being involved in HPA activity from longitudinally sampled hormone concentrations. HPA activity can be quantified either by (a) discrete-time, or by (b) continuous-time models. Although the former is the most popular and more convenient approach (as indicated by the overly frequent encounter of ANOVAs and trapezoidal AUC calculations in the field of psychobiological stress research), most discrete time models form rather data-driven, descriptive approaches to quantify HPA activity, that assume the existence of some endocrine resting-state (i.e., a baseline) at the first sampling point and disregard any mechanistic hormonal change occurring in between all following sampling points. Even if one ignores the fact, that such properties are unlikely to pertain to endocrine systems in general, many generic discrete time models fail to account for the specific structure of endocrine data that results from biochemical hormone measurement, as well as from the dynamics of the investigated system. More precisely speaking, cortisol time series violate homoscedasticity, residual normality, and sphericity, which need to be present in order to enable (mixed effects) GLM-based analyses. Neglecting these prerequisites may lead to inference bias unless counter-measures are taken.
Such counter-measures usually involve alteration of the scale of hormone concentrations via transformation techniques. As such, a fourth-root transformation of salivary cortisol (being determined by a widely used, commercially available immunoassay) is shown to yield the optimal tradeoff for generating homoscedasticity and residual normality simultaneously. Although the violation of sphericity could be partly accounted for by several correction techniques, many modern software packages for structural equation modeling (e.g., Mplus, OpenMX, Lavaan) also offer the opportunity to easily specify more appropriate moment structures via path notation and therefore to relax the modeling assumptions of GLM approaches to the analysis of longitudinal hormone data.
Proceeding from this reasoning, this thesis illustrates how one can additionally incorporate hypotheses about HPA functioning, and thus model all relevant sub-processes that give rise to HPA kinetics and dynamics. The ALT modeling framework being advocated within this thesis, is shown to serve well for this purpose: ALT modeling can recover HPA activity parameters, which are directly interpretable within a physiological framework, that is, distinct growth factors representing the amount of secreted cortisol and velocity of cortisol elimination can serve to interpret HPA reactivity and regulation in a more unambiguous way, as compared to GLM effect measures. For illustration of these advantages on a content level, cortisol elimination after stress induction was found to be elevated as compared to its known pharmacokinetics. While the mechanism behind this effect requires further investigation, its detection would obviously have been more difficult upon application of conventional GLM methods. Further extension of the ALT framework allowed to address a methodological question, which had previously been dealt with by a mere rule of thumb; what’s the optimal threshold criterion, that enables a convenient but comparably accurate classification of individuals whose HPA axis is or is not activated upon encountering a stressful situation? While a rather arbitrarily chosen baseline-to-peak threshold of 2.5 nmol/L was commonly used to identify episodes of secretory HPA activity in time series of salivary cortisol concentrations, a reanalysis of a TSST meta- dataset by means of ALT mixture modeling suggested that this 2.5 nmol/L criterion is overly conservative with modern biochemical measurement tools and should be lowered according to the precision of the utilized assay (i.e., 1.5 nmol/L).
In sum, parametric ALT modeling of endocrine activity can provide a convenient alternative to the commonly utilized GLM-based approaches that enables the inference on and quantification of distinct HPA components on a theoretical foundation, and thus to bridge the gap between discrete- and continuous-time modeling frameworks. The implementation of the outlined modeling approaches by the respective statistical syntaxes and practical guidelines being derived from the comparison of cortisol assays mentioned above, are provided in the appendix of the present thesis, which will hopefully help stress researchers to directly quantify the construct they actually intend to assess.
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Reglin, Bettina, Timothy W. Secomb, and Axel R. Pries. "Structural Control of Microvessel Diameters: Origins of Metabolic Signals." FRONTIERS MEDIA SA, 2017. http://hdl.handle.net/10150/626059.
Повний текст джерелаАнотація:
Diameters of microvessels undergo continuous structural adaptation in response to hemodynamic and metabolic stimuli. To ensure adequate flow distribution, metabolic responses are needed to increase diameters of vessels feeding poorly perfused regions. Possible modes of metabolic control include release of signaling substances from vessel walls, from the supplied tissue and from red blood cells (RBC). Here, a theoretical model was used to compare the abilities of these metabolic control modes to provide adequate tissue oxygenation, and to generate blood flow velocities in agreement with experimental observations. Structural adaptation of vessel diameters was simulated for an observed mesenteric network structure in the rat with 576 vessel segments. For each mode of metabolic control, resulting distributions of oxygen and deviations between simulated and experimentally observed flow velocities were analyzed. It was found that wall-derived and tissue-derived growth signals released in response to low oxygen levels could ensure adequate oxygen supply, but RBC-derived signals caused inefficient oxygenation. Closest agreement between predicted and observed flow velocities was obtained with wall-derived growth signals proportional to vessel length. Adaptation in response to oxygen-independent release of a metabolic signal substance from vessel walls or the supplied tissue was also shown to be effective for ensuring tissue oxygenation due to a dilution effect if growth signal substances are released into the blood. The present results suggest that metabolic signals responsible for structural adaptation of microvessel diameters are derived from vessel walls or from perivascular tissue.
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Webster, Duncan James. "A combined experimental and computational model for genetic control of micro structural bone adaptation /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17851.
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Naderan-Tahan, Khosro. "Stress analysis of spherical shells with one and/or two neighbouring nozzles using internal pressure and external loadings by finite element method : a parametric survey." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242464.
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Clark, Michele Candice. "Structural-functional aspects of caring for elders in the home environment." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184912.
Повний текст джерелаАнотація:
The purpose of this study was to identify variables that facilitate lay caregivers in maintaining dependent elders in the home setting. Specifically, this study: (1) tested a deduced theory designed to explain home maintenance of a dependent elder; (2) examined the relationship between the following variables: Seriousness of an Elder's Illness, Caregiver Overload, Quality of Care, Learning State, Caregivers Maintenance Ability, Acceptance of the Maintenance Role and the Caregiver's Perception of Power; and (3) evaluated the reliability and validity of the instruments that measured the proposed variables. A descriptive correlational design with causal modeling methodology was used to assess a five stage theory. The convenience sample was comprised of 70 English speaking caregivers providing a minimum of five hours of direct care to a dependent elder in the home setting. Reliability and validity of the instruments used to evaluate the theoretical concepts were assessed by Cronbach's alpha, factor analysis and predictive model testing. Multiple regression statistics were used to evaluate the theory and residual analysis was used to assess violations of statistical and causal modeling assumptions. The findings supported two of the predicted relationships: Seriousness of Illness had a direct and positive relationship with Caregiver Overload (B =.60, R² =.35) and Learning State had a direct and positive influence on Acceptance of the Maintenance Role (B =.36, R² =.18). As the disabilities of the dependent elder became more acute, the caregivers' feelings of being overloaded with the burden of the caregiving responsibilities increased. However, when the caregivers had a positive perception of their abilities to implement prescribed health care instruction as well as felt positively about their caregiving role (Learning State), they spent a greater amount of time giving direct care to the dependent elder (Acceptance of Maintenance Role). Identification of learning needs as they relate to the caregivers' ability to understand and implement health care instruction as well as feel positively about their role, can assist nurses in developing appropriate teaching interventions. The expected outcome of these interventions is direct care provided by the caregiver to the dependent elder.
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Ding, Jie. "Structural and fluid analysis for large scale PEPA models, with applications to content adaptation systems." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/7975.
Повний текст джерелаАнотація:
The stochastic process algebra PEPA is a powerful modelling formalism for concurrent systems, which has enjoyed considerable success over the last decade. Such modelling can help designers by allowing aspects of a system which are not readily tested, such as protocol validity and performance, to be analysed before a system is deployed. However, model construction and analysis can be challenged by the size and complexity of large scale systems, which consist of large numbers of components and thus result in state-space explosion problems. Both structural and quantitative analysis of large scale PEPA models suffers from this problem, which has limited wider applications of the PEPA language. This thesis focuses on developing PEPA, to overcome the state-space explosion problem, and make it suitable to validate and evaluate large scale computer and communications systems, in particular a content adaption framework proposed by the Mobile VCE. In this thesis, a new representation scheme for PEPA is proposed to numerically capture the structural and timing information in a model. Through this numerical representation, we have found that there is a Place/Transition structure underlying each PEPA model. Based on this structure and the theories developed for Petri nets, some important techniques for the structural analysis of PEPA have been given. These techniques do not suffer from the state-space explosion problem. They include a new method for deriving and storing the state space and an approach to finding invariants which can be used to reason qualitatively about systems. In particular, a novel deadlock-checking algorithm has been proposed to avoid the state-space explosion problem, which can not only efficiently carry out deadlock-checking for a particular system but can tell when and how a system structure lead to deadlocks. In order to avoid the state-space explosion problem encountered in the quantitative analysis of a large scale PEPA model, a fluid approximation approach has recently been proposed, which results in a set of ordinary differential equations (ODEs) to approximate the underlying CTMC. This thesis presents an improved mapping from PEPA to ODEs based on the numerical representation scheme, which extends the class of PEPA models that can be subjected to fluid approximation. Furthermore, we have established the fundamental characteristics of the derived ODEs, such as the existence, uniqueness, boundedness and nonnegativeness of the solution. The convergence of the solution as time tends to infinity for several classes of PEPA models, has been proved under some mild conditions. For general PEPA models, the convergence is proved under a particular condition, which has been revealed to relate to some famous constants of Markov chains such as the spectral gap and the Log-Sobolev constant. This thesis has established the consistency between the fluid approximation and the underlying CTMCs for PEPA, i.e. the limit of the solution is consistent with the equilibrium probability distribution corresponding to a family of underlying density dependent CTMCs. These developments and investigations for PEPA have been applied to both qualitatively and quantitatively evaluate the large scale content adaptation system proposed by the Mobile VCE. These analyses provide an assessment of the current design and should guide the development of the system and contribute towards efficient working patterns and system optimisation.
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Merland, Romain. "Génération de grilles de type volumes finis : adaptation à un modèle structural, pétrophysique et dynamique." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0037/document.
Повний текст джерелаАнотація:
Cet ouvrage aborde la génération de grilles de Voronoï sous contrainte pour réduire les erreurs liées à la géométrie des cellules lors de la simulation réservoir. Les points de Voronoï sont optimisés en minimisant des fonctions objectif correspondant à différentes contraintes géométriques. L'originalité de cette approche est de pouvoir combiner les contraintes simultanément : - la qualité des cellules, en plaçant les points de Voronoï aux barycentres des cellules ; - le raffinement local, en fonction d'un champ de densité [rho], correspondant à la perméabilité, la vitesse ou la vorticité ; - l'anisotropie des cellules, en fonction d'un champ de matrice M contenant les trois vecteurs principaux de l'anisotropie, dont l'un est défini par le vecteur vitesse ou par le gradient stratigraphique ; - l'orientation des faces des cellules, en fonction d'un champ de matrice M contenant les trois vecteurs orthogonaux aux faces, dont l'un est défini par le vecteur vitesse ; - la conformité aux surfaces du modèle structural, failles et horizons ; - l'alignement des points de Voronoï le long des puits. La qualité des grilles générées est appréciée à partir de critères géométriques et de résultats de simulation comparés à des grilles fines de référence. Les résultats indiquent une amélioration de la géométrie, qui n'est pas systématiquement suivie d'une amélioration des résultats de simulationVoronoi grids are generated under constraints to reduce the errors due to cells geometry during flow simulation in reservoirs. The Voronoi points are optimized by minimizing objective functions relevant to various geometrical constraints. An original feature of this approach is to combine simultaneously the constraints: - Cell quality, by placing the Voronoi points at the cell barycenters. - Local refinement according to a density field rho, relevant to permeability, velocity or vorticity. - Cell anisotropy according to a matrix field M built with the three principal vectors of the anisotropy, which one is defined by the velocity vector or by the stratigraphic gradient. - Faces orientation according to a matrix field M built with the three vectors orthogonal to the faces, which one is defined by the velocity vector. - Conformity to structural features, faults and horizons. - Voronoï points alignment along well path. The quality of the generated grids is assessed from geometrical criteria and from comparisons of flow simulation results with reference fine grids. Results show geometrical improvements, that are not necessarily followed by flow simulation results improvements
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Sternchüss, Arnaud. "Multi-level parametric reduced models of rotating bladed disk assemblies." Phd thesis, Ecole Centrale Paris, 2009. http://tel.archives-ouvertes.fr/tel-00366252.
Повний текст джерелаАнотація:
Les disques aubagés, que l'on trouve dans les turbomachines, sont des structures complexes dont le comportement vibratoire est généralement déterminé par l'exploitation de conditions de symétrie dans leur configuration nominale. Cette symétrie disparaît lorsque l'on assemble plusieurs de ces disques pour former un rotor ou que l'on introduit une variabilité spatiale des paramètres mécaniques (on parle de désaccordage intentionnel ou non). Le raffinement des maillages, nécessaire à une évaluation correcte de la répartition des contraintes, conduirait à des modèles de rotor complet de taille prohibitive (plusieurs dizaines de millions de degrés de liberté). L'objectif de cette thèse est donc l'introduction de méthodologies de réduction qui par combinaison de calculs acceptables permettent d'étudier de façon fine la dynamique d'ensemble sur des modèles 3D fins multi-étages et potentiellement désaccordés. L'étude des transformations de Fourier séparées des réponses de chaque étage permet, dans un premier temps, de bien comprendre les effets de couplage inter-harmonique liés au couplage inter-disque et au désaccordage. A partir de ce constat, une première méthode utilise les résultats de calculs en symétrie cyclique et à secteur encastré pour construire un modèle de secteur exact pour certains modes dits cibles et de très bonne qualité pour les autres modes. Cette méthode est ensuite étendue au cas multi-étage en construisant des bases de réduction de secteur par combinaison de solutions mono-harmoniques. Les illustrations montrent que la méthodologie proposée permet le traitement de modèles de très grande taille, tout en restant compatible avec une grande richesse de post-traitements (calculs de modes, calculs de réponses forcées, analyses de leur contenu harmonique spatial, répartition d'énergie et effets de localisation...). La méthodologie est enfin étendue à la gestion de modèles paramétrés en vitesse de rotation. L'enrichissement des ensembles de modes cibles par des calculs à trois vitesses permet ainsi une reconstruction rapide de l'évolution des fréquences pour l'ensemble d'un intervalle.
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El, Mendili Mohamed-Mounir. "Analysis of the structural integrity of the spinal cord in motor neuron diseases using a multi-parametric MRI approach." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066575/document.
Повний текст джерелаАнотація:
Les pathologies du motoneurone sont caractérisées par une atteinte progressive des motoneurones au niveau de la corne antérieur de la moelle épinière. Au delà de cette susceptibilité anatomique commune, qui est responsable d’une atteinte motrice progressive et diffuse dans ces pathologies, d’autres systèmes neurologiques sont touchés. La dégénérescence du faisceau corticospinal est une caractéristique classique dans la sclérose latérale amyotrophique, qui est la maladie du motoneurone la plus commune chez l’adulte. Cependant, il est de plus en plus reconnu que la SLA est une maladie multisystémique. En particulier, une atteinte précoce du système sensoriel a été démontrée dans la modèle animal de la SLA ainsi que dans l’amyotrophie spinal liée à la mutation du gène SMN1 (survival motor neuron 1 en anglais). Chez les patients, l’imagerie par résonance magnétique (IRM) a émergé comme l’approche la plus performant à l’étage cérébral, permettant d’extraire des indices quantitatifs sur la perte neuronale, la dégénérescence axonale et la démyélinisation dans les pathologies neurodégénératives. Cependant, l’investigation de l’étage médullaire dans ces pathologies est difficile à mener à cause des nombreux défis techniques et méthodologiques que représente l’IRM de la moelle épinière.L’objectif de ce projet de thèse a été d’utiliser l’approche IRM multiparamétrique au niveau de la moelle épinière pour analyser les structures de la matière grise et blanche qui sont atteintes dans deux des pathologies du motoneurone les plus répondues, c’est-à-dire la SLA et la SMA, leurs altérations au cours du temps et leurs corrélations fonctionnelles avec les données cliniques et électrophysiologiquesDegenerative motor neuron diseases (MND) are characterized by a progressive dysfunction and loss of ventral horn motor neurons of the spinal grey matter. Beyond this common anatomical susceptibility, which is responsible for a progressive and diffuse weakness, other neurological systems are also impaired. The corticospinal tract (CST) degeneration is a classical feature of amyotrophic lateral sclerosis (ALS), which is the most common adult onset motor neuron disease, but a more widespread multisystem involvement is now well recognized. In particular, early sensory system involvement has been demonstrated in animal models of ALS and also of survival motor neuron 1 gene linked spinal muscular atrophy (SMN1-linked SMA). In human patients, magnetic resonance imaging (MRI) has emerged as the most powerful approach at the brain level to extract quantitative data on neuronal loss, axonal degeneration and demyelination in degenerative conditions. Studies at the spinal cord levels are scarce mainly because of technical and methodological difficulties. The objective of the present thesis project was to use a multi-parametric MRI approach at the spinal cord level to analyze grey and white matter structures that are impaired in two most common MND, i.e. ALS and SMN1-linked SMA, their temporal alterations during the disease course and the functional correlates, as assessed by clinical and electrophysiological examinations
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Lee, Karla Chui Luan. "Structural adaptation of the mouse ulna to mechanical loading and the involvement of estrogen receptor α." Thesis, Royal Veterinary College (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401718.
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Gates, Michael S. "Devaluing Stigma in the Context of Forgiveness, Coping and Adaptation: a Structural Regression Model of Reappraisal." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115083/.
Повний текст джерелаАнотація:
The 2010 National HIV/AIDS Strategy outlined three important goals for managing the current HIV pandemic in the U.S.: (1) reduce the number of people who become infected with HIV; (2) improve access to health care and health-related outcomes for people living with HIV/AIDS (PLH/A); and (3) reduce HIV-related health disparities. Each of these goals tacitly depends upon reducing HIV-related stigma, and this study examined how HIV+ individuals evaluate coping efforts to overcome stigma’s impact on quality of life (QOL). a structural regression model was developed to instantiate the reappraisal process described by Lazarus and Folkman’s transactional theory of stress and coping, and this model indicated that maladaptive coping fully mediated the relationship between dispositional forgiveness and perceived stigma, which supports the prediction that coping efficacy is related to stress reduction. Additionally, maladaptive coping fully mediated the relationship between dispositional forgiveness and QOL, supporting the contention that forgiveness is a critical aspect to the evaluative process that influences how PLH/A cope with stigma. Lastly, the model showed that when PLH/A engaged in maladaptive coping to mitigate stress-related stigma, these individuals experienced increased stigmatization and reported significantly lower levels of health-related QOL. in contrast, PLH/A that reported higher levels of dispositional forgiveness were significantly less likely to use maladaptive coping to overcome stigma. Therefore, dispositional forgiveness works through coping to alter perceptions regarding stigmatization, while indirectly influencing attitudes related to health distress, mental health, and cognitive and social functioning. the theoretical and clinical implications of these findings are discussed.
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HaQuang, Ninh. "The response of multidegree-of-freedom systems with quadratic and cubic nonlinearities subjected to parametric and external excitations." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49787.
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Karlsson, Susanne. "Terminology in the Translation of TwoTexts on Structural Engineering." Thesis, Linnéuniversitetet, Institutionen för språk och litteratur, SOL, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-13519.
Повний текст джерелаАнотація:
This paper is about the handling of challenging terminology within the technical field of structural engineering. The translation of two texts on structural systems "Antiquated Structural Systems Series", published in STRUCTURE magazine, serves as the basis for this study. The analysis focuses on the search and textual strategies for a selection of difficult terms. The terms are divided into four groups: terms with no Swedish equivalent; terms with more than one Swedish equivalent; acronyms; and measurements. The analysis shows that the search strategies are the same, regardless of term type, and that they involve many steps, including looking for terms in dictionaries and term banks; comparing terms in encyclopedias and parallel texts; and confirming usage. The textual strategies that were helpful in the translation were procedures based on the theories of Vinay and Darbelnet (in Munday 2008) and Ingo (2007), such as literal translation, borrowing, calque, adaptation and addition. The result shows that the chosen textual strategy for each challenging term differed greatly and depended on, for example, context and translator preference.