To see the other types of publications on this topic, follow the link: Multi factor response surface.
Dissertations / Theses on the topic 'Multi factor response surface'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 47 dissertations / theses for your research on the topic 'Multi factor response surface.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Qu, Xueyong. "Reliability-based structural optimization using response surface approximations and probabilistic sufficiency factor." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0004395.
Full text
2
Truong, David Hien. "Single-Step Factor Screening and Response Surface Optimization Using Optimal Designs with Minimal Aliasing." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/64.
Full textAbstract:
Cheng and Wu (2001) introduced a method for response surface exploration using only one design by using a 3-level design to first screen a large number of factors and then project onto the significant factors to perform response surface exploration. Previous work generally involved selecting designs based on projection properties first and aliasing structure second. However, having good projection properties is of little concern if the correct factors cannot be identified. We apply Jones and Nachtsheim’s (2009) method for finding optimal designs with minimal aliasing to find 18, 27, and 30-run designs to use for single-step screening and optimization. Our designs have better factor screening capabilities than the designs of Cheng and Wu (2001) and Xu et al. (2004), while maintaining similar D-efficiencies and allowing all projections to fit a full second order model.
3
Lombardi, Anna. "Linear and ultrafast response of individual multi-material nanoparticles." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10141.
Full textAbstract:
Les propriétés optiques et vibrationnelles de nanoparticules métalliques individuelles ont été étudiées par spectroscopie par modulation spatiale (SMS), avec une attention particulière aux effets de forme, composition, environnement local, ainsi que de couplage inter-particule. La réponse optique de nanoparticules (métalliques au cœur-couronne métal-diélectrique) allongées et des particules bimétalliques (hétérodimères or-argent) a été mesuré et en suite interprétée grâce à une corrélation avec la caractérisation morphologique de la même particule obtenue par microscopie à transmission électronique et avec des simulations par éléments finis prenants en compte la réelle géométrie du nano-objet et le substrat. Une technique pompe sonde résolue en temps a été en suite utilisée pour étudier le profil Fano dans l'absorption d'une particule d'or au sein d'un hétérodimères or-argent. Sur une échelle de temps des quelques dizaines de picosecondes, les vibrations acoustiques multimodales de nanobipyramides d'or individuelles ont été optiquement détectées et caractérisées par rapport à un modèle élastique classiqueOptical and vibrational properties of individual metal-based nanoparticles have been investigated by spatial modulation spectroscopy (SMS), focusing on their dependence on nano-object shape, composition, environment and inter-particle coupling. Quantitative investigations of the optical response, and in particular, the surface plasmon resonance (extinction cross-section amplitude, spectral position and linewidth) of elongated metal or metal-dielectric (gold nanorods, nanobipyramids with or without silica coating) and bimetallic (gold-silver heterodimers) nanoparticles deposited on a substrate have first been performed. The same nanoparticles were characterized by electron microscopy permitting quantitative interpretation of their optical response using finite element numerical simulations, taking into account the influence of the substrate. Combining SMS microscopy with a high sensitivity femtosecond two-color pump-probe setup, the ultrafast dynamics of single nano-objects has been investigated. The Fano absorption profile of a gold nanoparticle within a single gold-silver heterodimer, a parameter not accessible by linear spectroscopy, was directly measured. On a picosecond time-scale, multimodal acoustic vibrations of single gold nanobipyramids were optically lunched and detected, and their features compared to a model based on continuum elasticity
4
Demko, Daniel Todd. "Tools for Multi-Objective and Multi-Disciplinary Optimization in Naval Ship Design." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/31743.
Full textAbstract:
This thesis focuses on practical and quantitative methods for measuring effectiveness in naval ship design. An Overall Measure of Effectiveness (OMOE) model or function is an essential prerequisite for optimization and design trade-off. This effectiveness can be limited to individual ship missions or extend to missions within a task group or larger context. A method is presented that uses the Analytic Hierarchy Process combined with Multi-Attribute Value Theory to build an Overall Measure of Effectiveness and Overall Measure of Risk function to properly rank and approximately measure the relative mission effectiveness and risk of design alternatives, using trained expert opinion to replace complex analysis tools. A validation of this method is achieved through experimentation comparing ships ranked by the method with direct ranking of the ships through war gaming scenarios.
The second part of this thesis presents a mathematical ship synthesis model to be used in early concept development stages of the ship design process. Tools to simplify and introduce greater accuracy are described and developed. Response Surface Models and Design of Experiments simplify and speed up the process. Finite element codes such as MAESTRO improve the accuracy of the ship synthesis models which in turn lower costs later in the design process. A case study of an Advanced Logistics Delivery Ship (ALDV) is performed to asses the use of RSM and DOE methods to minimize computation time when using high-fidelity codes early in the naval ship design process.Master of Science
5
Hadjiilias, Hippokrates A. "The aerodynamic design and optimization of a wing-fuselage junction fillet as part of a multi-disciplinary optimization process during the early aircraft design stages." Thesis, Cranfield University, 1996. http://hdl.handle.net/1826/3443.
Full textAbstract:
An attempt to minimize interference drag in a wing-fuselage junction by means
of inserting a fillet is presented in this thesis. The case of a low-wing com-
mercial transport aicraft at cruise conditions is examined. Due to the highly
three dimensional behaviour of the flow field around the junction, a thin-layer
Navier-Stokes code was implemented to estimate the drag forces at the junc-
tion. Carefully selected design variable combinations based on-the theory of
Design of Experiments constituted the initial group of feasible cases for which
the flow solver had to be run. The drag values of these feasible cases were then
used to create a second order response surface which could predict with rea-
sonable accuracy the interference drag given the value of the design variables
within the feasible region. A further optimization isolated the minimum in-
terference drag combination of design variable values within the design space.
The minimurn interference drag combination of design variable values was eval-
uated numerically by the flow solver. The prediction of the response surface
and the numerical value obtained by the flow solver for the interference drag
of the optimal wing-fuselage combination differed by less than five percent. To demonstrate the ability of the method to be used in an interdisciplinary
analysis and optimization program, a landing gear design module is included
which provides volume constraints on the fillet geometry during the fillet sur-
face definition phase.
The Navier Stokes flow analyses were performed on the Cranfield Cray su-
percomputer. Each analysis required between eight to twelve CPU hours, and
the total CPU time required for the optimization of the six variable model
described in the thesis required thirty Navier Stokes runs implementing the
Design of Experimens and Surface Response Methodology implementation.
For comparison, a typical optimization implementing a classical conjugate di-
rections optimizer with no derivative information available would probably
require more than forty iterations.
Both the optimization and the flow solver results are discussed and some
recommendations for improving the efficiency of the code and for further ap-
plications of the method are given.
6
Tu, Wei. "Response modelling of pavement subjected to dynamic surface loading based on stress-based multi-layered plate theory." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1188066023.
Full text
7
Chantarat, Navara. "Modern design of experiments methods for screening and experimentations with mixture and qualitative variables." Columbus, OH : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1064198056.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xiv, 119 p.: ill. (some col.). Includes abstract and vita. Advisor: Theodore T. Allen, Dept. of Industrial and Systems Engineering. Includes bibliographical references (p. 111-119).
8
Liu, Mingchun. "Functional characterization of Sl-ERF.B3, a member of the large multi-gene family of Ethylene Response Factor in tomato (Solanum lycopersicum)." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0089/document.
Full textAbstract:
Les derniers acteurs de la voie de signalisation à l’éthylène sont des facteurs de transcription appelés ERF (Ethylene Response Factors). La connaissance de leur rôle spécifique dans la régulation des processus développementaux dépendant de l’éthylène reste limitée. Les travaux présentés dans la thèse concernent la caractérisation fonctionnelle du gène Sl-ERF.B3, un membre de cette grande famille de régulateurs transcriptonnels dans la tomate (Solanum lycopersicum). Utilisant une stratégie répresseur dominant ; il est montré en particulier que ce gène intervient dans la mise en place de la réponse à l’éthylène et dans le contrôle de la maturation du fruit. L’expression d’une construction ERF.B3-SRDX, une version chimérique de Sl-ERF.B3 fusionné à un domaine répresseur de type EAR, entraine des phénotypes pléotropiques aussi bien dans la signalisation de l’éthylène que dans le développement des parties végétatives et des organes reproducteurs. Ainsi, une altération de la triple réponse à l’éthylène est constatée chez les lignées transgéniques et au stade adulte, les plantes présentent des phénotypes d’épinastie des feuilles, de sénescence prématurée des fleurs et d’abscission accélérée des fruits. L’ensemble de ces observations est corrélée avec une modification de l’expression de gènes impliqués dans la biosynthèse et la réponse à l’éthylène. Ces données suggèrent que ERF.B3 intervient dans un mécanisme de rétro-control de la réponse à l’éthylène en agissant à la fois sur les gènes de biosynthèse et de signalisation de l’hormone. Au niveau du fruit, la sur-expression d’ERF.B3-SRDX entraine une modification du processus de maturation avec un retard notable de l’avènement de l’acquisition de la compétence à murir. Cependant, une fois la maturation initiée, elle s’accompagne d’une forte production d’éthylène et d’une accélération du ramollissement du fruit. A l’inverse, l’accumulation de pigment est inhibée par altération de la voie de biosynthèse des caroténoïdes. Ces données phénotypiques sont corrélées avec le niveau d’expression des gènes clés impliqués dans ces processus. Les résultats indiquent que dans les lignées transgéniques, il y a découplage de certaines caractéristiques de la maturation du fruit et permettent de mettre en lumière le rôle d’ERF.B3 dans la régulation des processus de développement dépendant de l’éthylène chez la tomateEthylene Response Factors (ERFs) are known to be the last transcription factors of the ethylene transduction pathway. Their specific role in ethylene-dependent developmental processes remains poorly understood. This work demonstrated a specific role of Sl- ERF.B3, a member of the ERF gene family in tomato (Solanum lycopersicum), in mediating ethylene response and fruit ripening through a dominant repressor strategy. ERF.B3-SRDX dominant repressor etiolated seedlings displayed partial constitutive ethylene-response in the absence of ethylene and adult plants exhibited typical ethylenerelated alterations such as leaf epinasty, premature flower senescence and accelerated fruit abscission. The multiple symptoms related to enhanced ethylene sensitivity correlate with the altered expression of ethylene biosynthesis and signaling genes, suggesting the involvement of Sl-ERF.B3 in a feedback mechanism regulating components of ethylene production and response. In addition, over-expression of ERF.B3-SRDX in tomato results in alterations in both fruit morphology and ripening process. The attainment of competence to ripen is dramatically delayed in ERF.B3-SRDX fruits but once ripening proceeds it is associated with high climacteric ethylene production and enhanced fruit softening while pigment accumulation is strongly reduced. Moreover, a number of genes involved in the fruit ripening process showed expression pattern deviating from that of wild type. These data suggest a putative role of Sl-ERF.B3 in the transcriptional network underlying the ripening process and uncover a mean for uncoupling some of the main features of fruit ripening such as fruit softening and pigment accumulation. Overall, the study highlighted the importance of an ERF gene in ethylene-mediated developmental processes such as plant growth and fruit ripening
9
Amouzgar, Kaveh. "Metamodel based multi-objective optimization." Licentiate thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-28432.
Full textAbstract:
As a result of the increase in accessibility of computational resources and the increase in the power of the computers during the last two decades, designers are able to create computer models to simulate the behavior of a complex products. To address global competitiveness, companies are forced to optimize their designs and products. Optimizing the design needs several runs of computationally expensive simulation models. Therefore, using metamodels as an efficient and sufficiently accurate approximate of the simulation model is necessary. Radial basis functions (RBF) is one of the several metamodeling methods that can be found in the literature. The established approach is to add a bias to RBF in order to obtain a robust performance. The a posteriori bias is considered to be unknown at the beginning and it is defined by imposing extra orthogonality constraints. In this thesis, a new approach in constructing RBF with the bias to be set a priori by using the normal equation is proposed. The performance of the suggested approach is compared to the classic RBF with a posteriori bias. Another comprehensive comparison study by including several modeling criteria, such as problem dimension, sampling technique and size of samples is conducted. The studies demonstrate that the suggested approach with a priori bias is in general as good as the performance of RBF with a posteriori bias. Using the a priori RBF, it is clear that the global response is modeled with the bias and that the details are captured with radial basis functions. Multi-objective optimization and the approaches used in solving such problems are briefly described in this thesis. One of the methods that proved to be efficient in solving multi-objective optimization problems (MOOP) is the strength Pareto evolutionary algorithm (SPEA2). Multi-objective optimization of a disc brake system of a heavy truck by using SPEA2 and RBF with a priori bias is performed. As a result, the possibility to reduce the weight of the system without extensive compromise in other objectives is found. Multi-objective optimization of material model parameters of an adhesive layer with the aim of improving the results of a previous study is implemented. The result of the original study is improved and a clear insight into the nature of the problem is revealed.
10
Raut, Vivek P. "METHODS TO QUANTITATIVELY ASSESS THE PERFORMANCE OF CONNECTIVE TISSUE PROGENITOR CELLS IN RESPONSE TO SURFACE MODIFIED BIOMATERIALS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1372334668.
Full text
11
Hammadi, Moncef. "Contribution à l'intégration de la modélisation et la simulation multi-physique pour conception des systèmes mécatroniques." Phd thesis, Ecole Centrale Paris, 2012. http://tel.archives-ouvertes.fr/tel-00711469.
Full textAbstract:
Le verrou de l'intégration de la simulation multi-physique dans la conception des systèmes mécatroniques est lié, entre autres, aux problèmes d'interopérabilité entre les outils de simulation. Ces problèmes engendrent des difficultés pour assurer des optimisations multidisciplinaires. Dans cette thèse, nous avons développé une approche de conception intégrée permettant de franchir cet obstacle. Cette approche s'appuie sur l'utilisation d'une plateforme d'intégration permettant de coupler divers outils de modélisation et de simulation. La modélisation du comportement multi-physique des composants au niveau détaillé est assurée par les méta-modèles, également utilisés pour l'optimisation multidisciplinaire des composants du système mécatronique. Ces méta-modèles permettent aussi d'intégrer le comportement multi-physique des composants et des modules mécatroniques pour la simulation au niveau système. Cette approche a été validée avec une modélisation d'un véhicule électrique. Ainsi, le niveau conceptuel de modélisation a été effectué avec le langage de modélisation des systèmes SysML et la véri_cation d'un test de performance d'accélération a été réalisée avec le langage de modélisation Modelica. Le module de conversion de puissance électrique du véhicule avec les fils de bonding a été modélisé avec la CAO 3D et son comportement multi-physique a été vérifié avec la méthode des éléments finis. Des méta-modèles sont ainsi élaborés en utilisant les techniques de surfaces de réponse et les réseaux de neurones de fonctions à base radiale. Ces méta-modèles ont permis ensuite d'effectuer des optimisations géométriques bi-niveaux du convertisseur de puissance et des fils de bonding. Le comportement électro-thermique du convertisseur de puissance et celui thermo-mécanique des fils de bonding ont été alors intégrés au niveau système à travers les méta-modèles. Les résultats montrent la flexibilité de l'approche du point de vue échange des méta-modèles et optimisation multidisciplinaire. Cette approche permet ainsi un gain très important du temps de conception, tout en respectant la précision souhaitée.
12
Marshall, Leslie Marie. "Multilevel Analysis of a Scale Measuring Educators’ Perceptions of Multi-Tiered Systems of Supports Practices." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6313.
Full textAbstract:
This study aimed to provide evidence of reliability and validity for the 42-item Perceptions of Practices Survey. The scale was designed to assess educators’ perceptions of the extent to which their schools were implementing multi-tiered system of supports (MTSS) practices. The survey was initially given as part of a larger evaluation project of a 3-year, statewide initiative designed to evaluate MTSS implementation. Elementary educators (Level-1 n = 2,109, Level-2 n = 62) completed the survey in September/October of 2007, September/October of 2008 (Level-1 n = 1,940, Level-2 n = 61), and January/February of 2010 (Level-1 n = 2,058, Level-2 n = 60). Multilevel exploratory and confirmatory factor analysis procedures were used to examine the construct validity and reliability of the instrument. Results supported a correlated four-factor model: Tiers I & II Problem Solving, Tier III Problem Identification, Tier III Problem Analysis & Intervention Procedures, and Tier III Evaluation of Response to Intervention. Composite reliability estimates for all factors across the three years approximated or exceeded .84. Additionally, relationships were found between the Perceptions of Practices Survey factors and another measure of MTSS implementation, the Tiers I & II Critical Components Checklist. Implications for future research regarding the psychometric properties of the survey and for its use in schools are discussed.
13
Escobar, Roberto Luiz. "Otimização de parametros de projeto de sistemas mecanicos atraves de algoritmo genetico multi-objetivos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264038.
Full textAbstract:
Orientador: Katia Lucchesi CavalcaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-08T21:19:55Z (GMT). No. of bitstreams: 1 Escobar_RobertoLuiz_M.pdf: 2961640 bytes, checksum: 516985920427d6083c04c1c5a22d6470 (MD5) Previous issue date: 2007
Resumo: Os sistemas mecânicos são projetados para desempenhar funções específicas, e por essa razão as suas funções devem ser medidas para garantir seu desempenho dentro de uma certa precisão ou tolerância. A grande complexidade em se projetar e analisar novos projetos é a inserção de novas tecnologias, que envolvem aspectos multidisciplinares. Assim, o desenvolvimento e melhoria de projetos e produtos colocam o engenheiro projetista frente às diversas fontes de variabilidade, como por exemplo, as propriedades dos materiais, condições operacionais e ambientais e incertezas nas suposições feitas sobre seu funcionamento. Em termos de modelagem matemática, as aproximações inerentes e hipóteses feitas durante a concepção do sistema, conduzem normalmente a diferentes respostas obtidas através de simulações e/ou medidas experimentais. Dessa forma, em uma fase anterior à modelagem matemática,durante a concepção do sistema ou produto, as aplicações de ferramentas estatísticas e métodos de otimização podem fornecer estimativas sobre faixas de valores ou valores ótimos para parâmetros significativos de projeto, dentro do espaço experimental estudado. Esse tipo de abordagem estatística teve sua fundamentação teórica durante as décadas de 20 e 30 por Fisher, com a aplicação da teoria estatística sob diversos aspectos, como por exemplo: testes de hipóteses, estimativa de parâmetros, seleção de modelos, planejamento experimental e, mais tarde, no controle e melhoria de processos e produtos. Assim, este trabalho propõe um procedimento de estudo e otimização, integrando a teoria de planejamento experimental, a metodologia da superfície de resposta e otimização multi-objetivos através de algoritmos genéticos, para se obter a otimização dos parâmetros de projeto de componentes mecânicos. Em específico, foram utilizados dados de um sistema rotor-mancal e o estudo implica em minimizar as amplitudes no domínio da freqüência. Outro objetivo deste trabalho, foi desenvolver um programa para otimização multi-objetivos através de algoritmos genéticos
Abstract: The mechanical systems are designed to be applied to any specific situations, and in this waytheir features should be measured to guarantee confidence to the systems. Their development and analysis expose the designer to a series of unknown parameters from several sources such as material properties, environmental and operational conditions. In terms of mathematical modeling, the inherent approximation and hypotheses made during system conception lead to different responses obtained by simulations and/or experimental measurements. So, in a previous phase of mathematical modeling, during the design analysis, the application of statistical tools and optimization methods is possible to estimate the values and/or ranges of the critical design parameters inside an experimental space. The connection between optimization and statistical data back at least to the early part of the 20th century and encompasses many aspects of applied and theoretical statistics, including hypothesis testing, parameter estimation, model selection, design of experiments and process and product control. So, this work proposes a link between theory of design of experiments, response surface methodology and multi-objective optimization using genetic algorithms, in order to optimize parameters for mechanical components. This study makes possible to verify the application of multi-objective optimization using genetic algorithms in design parameters and optimize them. A rotor-bearing system was used and amplitude in frequency domain was minimized. An experimental software for multi-objective optimization using genetic algorithm was developed.
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
14
Kolios, Athanasios. "A multi-configuration approach to reliability based structural integrity assessment for ultimate strength." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/5717.
Full textAbstract:
Structural Reliability treats uncertainties in structural design systematically,
evaluating the levels of safety and serviceability of structures. During the past
decades, it has been established as a valuable design tool for the description of
the performance of structures, and lately stands as a basis in the background of
the most of the modern design standards, aiming to achieve a uniform
behaviour within a class of structures. Several methods have been proposed for
the estimation of structural reliability, both deterministic (FORM and SORM) and
stochastic (Monte Carlo Simulation etc) in nature.
Offshore structures should resist complicated and, in most cases, combined
environmental phenomena of greatly uncertain magnitude (eg. wind, wave,
current, operational loads etc). Failure mechanisms of structural systems and
components are expressed through limit state functions, which distinguish a
failure and a safe region of operation. For a jacket offshore structure, which
comprises of multiple tubular members interconnected in a three dimensional
truss configuration, the limit state function should link the actual load or load
combination acting on it locally, to the response of each structural member. Cont/d.
15
Kolios, Athanasios Ioannis. "A multi-configuration approach to reliability based structural integrity assessment for ultimate strength." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/5717.
Full textAbstract:
Structural Reliability treats uncertainties in structural design systematically, evaluating the levels of safety and serviceability of structures. During the past decades, it has been established as a valuable design tool for the description of the performance of structures, and lately stands as a basis in the background of the most of the modern design standards, aiming to achieve a uniform behaviour within a class of structures. Several methods have been proposed for the estimation of structural reliability, both deterministic (FORM and SORM) and stochastic (Monte Carlo Simulation etc) in nature. Offshore structures should resist complicated and, in most cases, combined environmental phenomena of greatly uncertain magnitude (eg. wind, wave, current, operational loads etc). Failure mechanisms of structural systems and components are expressed through limit state functions, which distinguish a failure and a safe region of operation. For a jacket offshore structure, which comprises of multiple tubular members interconnected in a three dimensional truss configuration, the limit state function should link the actual load or load combination acting on it locally, to the response of each structural member. Cont/d.
16
Dinegdae, Yared Hailegiorgis. "Reliability-based Design Procedure for Flexible Pavements." Licentiate thesis, KTH, Byggvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165280.
Full textAbstract:
Load induced top-down fatigue cracking has been recognized recently as a major distress phenomenon in asphalt pavements. This failure mode has been observed in many parts of the world, and in some regions, it was found to be more prevalent and a primary cause of pavements failure. The main factors which are identified as potential causes of top down fatigue cracking are primarily linked to age hardening, mixtures fracture resistance and unbound layers stiffness. Mechanistic Empirical analytical models, which are based on hot mix asphalt fracture mechanics (HMA-FM) and that could predict crack initiation time and propagation rate, have been developed and shown their capacity in delivering acceptable predictions. However, in these methods, the effect of age hardening and healing is not properly accounted and moreover, these models do not consider the effect of mixture morphology influence on long term pavement performance. Another drawback of these models is, as analysis tools they are not suitable to be used for pavement design purpose. The main objective of this study is to develop a reliability calibrated design framework in load resistance factor design (LRFD) format which could be implemented to design pavement sections against top down fatigue cracking. For this purpose, asphalt mixture morphology based sub-models were developed and incorporated to HMA-FM to characterize the effect of aging and degradation on fracture resistance and healing potential. These sub-models were developed empirically exploiting the observed relation that exist between mixture morphology and fracture resistance. The developed crack initiation prediction model was calibrated and validated using pavement sections that have high quality laboratory data and observed field performance history. As traffic volume was identified in having a dominant influence on predicted performance, two separate model calibration and validation studies were undertaken based on expected traffic volume. The predictions result for both model calibration and validation was found to be in an excellent agreement with the observed performance in the field. A LRFD based design framework was suggested that could be implemented to optimize pavement sections against top-down fatigue cracking. To achieve this objective, pavement sections with various design target reliabilities and functional requirements were analyzed and studied. A simplified but efficient limit state equation was generated using a central composite design (CCD) based response surface methodology, and FORM based reliability analysis was implemented to compute reliabilities and formulate associated partial safety factors. A design example using the new partial safety factors have clearly illustrated the potential of the new method, which could be used to supplement existing design procedures.QC 20150427
17
Prabhu, Nikhil. "Material parameter identification of a thermoplastic using full-field calibration." Thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-170078.
Full textAbstract:
Finite element simulation of thermoplastic components is gaining importance as the companies aim to avoid overdesign of the components. Cost of the component can be minimized by using an adequate amount of material for its application. Life of the component, in a particular application, can be predicted as early as during its design phase with the help of computer simulations. To achieve reliable simulation results, an accurate material model which can predict the material behaviour is vital. Most material models consist of a number of material parameters that needs to be fed into them. These material parameters can be identified with the inputs from physical tests. The accuracy of the data extracted from the physical tests, however, remains the base for the aforementioned process. The report deals with the implementation of optical measurement technique such as Digital Image Correlation (DIC) in contrast with the conventional extensometers. A tensile test is conducted on a glass fibre reinforced thermoplastic specimen, according to ISO 527-2/1A, to extract the experimental data with the help of DIC technique. The material behavior is reproduced within a finite element analysis software package LS-DYNA, with the combination of elastoplastic model called *MAT_024 and stress state dependent damage and failure model called GISSMO. The tensile test is performed under quasi-static condition to rule out the strain rate dependency of the thermoplastic material. The mesh sensitivity of the damage model is taken into account with the element size regularization. The thesis concerns setting up a routine for material parameter identification of thermoplastics by full-field calibration (FFC) approach. Also, comparison of the strain field in the specimen, obtained through the newly set up routine against the regular non-FFC i.e. extensometer measurement routine. The major objective being, through the comparisons, a qualitative assessment of the two routines in terms of calibration time vs. gain in simulation accuracy. Material models obtained through both the routines are implemented in three-point and four-point bending simulations. The predicted material behaviors are evaluated against experimental tests.
18
Chibane, Hicham. "Contribution à l'optimisation multi-objectif des paramètres de coupe en usinage et apport de l 'analyse vibratoire : application aux matériaux métalliques et composites." Thesis, Tours, 2013. http://www.theses.fr/2013TOUR4053/document.
Full textAbstract:
Les procédés de fabrication de pièces mécaniques par enlèvement de matière (tournage, fraisage, perçage, ...) connaissent une utilisation massive dans l’industrie aéronautique et l’automobile. Les pièces obtenues par ces procédés doivent satisfaire à des propriétés géométriques, métallurgiques et à des caractéristiques de qualité. Pour répondre à ces exigences, plusieurs essais expérimentaux basés sur le choix des conditions de coupe sont souvent nécessaires avant d’aboutir à une pièce satisfaisante. Actuellement, ces méthodes empiriques basées sur l’expérience des fabricants et des utilisateurs des outils coupants sont souvent très longues et coûteuses, donnent une large plage de choix des paramètres en fonction de leurs besoins. Toutefois, le coût très élevé d’un essai limite fondamentalement le nombre d’expériences, avoir une pièce respectant les caractéristiques souhaitées avec un coût acceptable devient une tâche difficileManufacturing processes of mechanical parts by removal of material (turning, milling, drilling ...) have extensive use in aeronautic and automobile industry. The components obtained using these methods must satisfy geometric properties, metallurgical and quality characteristics. To meet these requirements, several experimental tests based on the selection of cutting conditions are often necessary before manufacturing. Currently, these empirical methods based on the experience of manufacturers and users of cutting tools (charts, diagrams with experimental findings, ...) are often very lengthy and costly. However, the high cost of a trial limits the number of experiments, so to have a deserted component with an acceptable cost is a difficult task. The importance of cutting conditions monitored by limitations is related to the type of material to be machined, since it determines the behavior of the machining
19
Xu, Yijun. "Uncertainty Quantification, State and Parameter Estimation in Power Systems Using Polynomial Chaos Based Methods." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/97876.
Full textAbstract:
It is a well-known fact that a power system contains many sources of uncertainties. These uncertainties coming from the loads, the renewables, the model and the measurement, etc, are influencing the steady state and dynamic response of the power system.
Facing this problem, traditional methods, such as the Monte Carlo method and the Perturbation method, are either too time consuming or suffering from the strong nonlinearity in the system.
To solve these, this Dissertation will mainly focus on developing the polynomial chaos based method to replace the traditional ones. Using it, the uncertainties from the
model and the measurement are propagated through the polynomial chaos bases at a set of collocation points. The approximated polynomial chaos coefficients contain the statistical information. The method can greatly accelerate the calculation efficiency while not losing the accuracy, even when the system is highly stressed.
In this dissertation, both the forward problem and the inverse problem of uncertainty quantification will be discussed. The forward problems will include the probabilistic power flow problem and statistical power system dynamic simulations. The generalized polynomial chaos method, the adaptive polynomial chaos-ANOVA method and the multi-element polynomial chaos method will be introduced and compared. The case studies show that the proposed methods have great performances in the statistical analysis of the large-scale power systems. The inverse problems will include the state and parameter estimation problem. A novel polynomial-chaos-based Kalman filter will be proposed. The comparison studies with other traditional Kalman filter demonstrate the good performances of the proposed Kalman filter. We further explored the area dynamic parameter estimation problem under the Bayesian inference framework. The polynomial-chaos-expansions are treated as the response surface of the full dynamic solver. Combing with hybrid Markov chain Monte Carlo method, the proposed method yields very high estimation accuracy while greatly reducing the computing time.
For both the forward problem and the inverse problems, the polynomial chaos based methods haven shown great advantages over the traditional methods. These computational techniques can improve the efficiency and accuracy in power system planning, guarantee the rationality and reliability in power system operations, and, finally, speed up the power system dynamic security assessment.PHD
20
Jahirul, Md Islam. "Experimental and statistical investigation of Australian native plants for second-generation biodiesel production." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/83778/9/Jahirul_Islam_Thesis.pdf.
Full textAbstract:
This work explores the potential of Australian native plants as a source of second-generation biodiesel for internal combustion engines application. Biodiesels were evaluated from a number of non-edible oil seeds which are grow naturally in Queensland, Australia. The quality of the produced biodiesels has been investigated by several experimental and numerical methods. The research methodology and numerical model developed in this study can be used for a broad range of biodiesel feedstocks and for the future development of renewable native biodiesel in Australia.
21
Havlásek, Radim. "Statistické plánování experimentů pro účely optimalizace kvality." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217910.
Full textAbstract:
This thesis is aimed to Design of Experiments methodology. Main purpose of this thesis is to create detailed materials for lessons of Design of Experiments in Quality Control courses. Thesis contains case studies which are applicable for education purposes. Design of Experiments has been applied for solder joints quality evaluation. Solder joints have been modeled in software ANSYS and finite element method has been applied for thermomechanical stress evaluation.
22
Chou, Yun-Hsin. "Servicescape symbolism." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/57199/1/Yun-Hsin_Chou_Thesis.pdf.
Full textAbstract:
In order to drive sustainable financial profitability, service firms make significant investments in creating service environments that consumers will prefer over the environments of their competitors. To date, servicescape research is over-focused on understanding consumers’ emotional and physiological responses to servicescape attributes, rather than taking a holistic view of how consumers cognitively interpret servicescapes. This thesis argues that consumers will cognitively ascribe symbolic meanings to servicescapes and then evaluate if those meanings are congruent with their sense of Self in order to form a preference for a servicescape. Consequently, this thesis takes a Self Theory approach to servicescape symbolism to address the following broad research question:
How do ascribed symbolic meanings influence servicescape preference?
Using a three-study, mixed-method approach, this thesis investigates the symbolic meanings consumers ascribe to servicescapes and empirically tests whether the joint effects of congruence between consumer Self and the symbolic meanings ascribed to servicescapes influence consumers’ servicescape preference. First, Study One identifies the symbolic meanings ascribed to salient servicescape attributes using a combination of repertory tests and laddering techniques within 19 semi-structured individual depth interviews. Study Two modifies an existing scale to create a symbolic servicescape meaning scale in order to measure the symbolic meanings ascribed to servicescapes. Finally, Study Three utilises the Self-Congruity Model to empirically examine the joint effects of consumer Self and servicescape on consumers’ preference for servicescapes. Using polynomial regression with response surface analysis, 14 joint effect models demonstrate that both Self-Servicescape incongruity and congruity influence consumers’ preference for servicescapes. Combined, the findings of three studies suggest that the symbolic meanings ascribed to servicescapes and their (in)congruities with consumers’ sense of self can be used to predict consumers’ preferences for servicescapes. These findings have several key theoretical and practical contributions to services marketing.
23
Alastal, Khalil. "Ecoulements oscillatoires et effets capillaires en milieux poreux partiellement saturés et non saturés : applications en hydrodynamique côtière." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0039/document.
Full textAbstract:
Dans cette thèse, on étudie les écoulements oscillatoires en milieux poreux (non saturés ou partiellement saturés) dus à des oscillations tidales des niveaux d'eau dans des milieux ouverts adjacents aux milieux poreux. L'étude est centrée sur le cas des plages de sable en hydrodynamique côtière, mais les applications concernent, potentiellement et plus généralement, les problèmes d'oscillation et de variation temporelle des niveaux d'eau dans des systèmes couplés, lorsque ceux-ci mettent en jeu des interactions entre les écoulements de sub-surface (milieux poreux) et les eaux de surface (milieux ouverts) : plages naturelles et artificielles; digues portuaires; barrages en terre; berges de fleuves; estuaires. Le forçage tidal des écoulements souterrains est représenté et modélisé ici, tant expérimentalement que numériquement, par une oscillation quasi-statique du niveau d'eau dans un réservoir externe ouvert, connecté au domaine poreux. On s'intéresse plus particulièrement aux écoulements verticaux forcés par une pression oscillatoire imposée au bas d'une colonne de sol. Sur le plan expérimental, ce type de forçage est obtenu par une machine à marée équipée d'un arbre rotatif. Au total, on utilise dans ce travail trois types d'approches (expérimentale, numérique, analytique), l'objectif étant d'étudier le mouvement vertical de la surface "libre" et l'écoulement non saturé sus-jacent, de façon à prendre en compte aussi bien les pertes de charge dans la zone saturée que les gradients de pression capillaire dans la zone non saturée. […]In this thesis, we study hydrodynamic oscillations in porous bodies (unsaturated or partially saturated), due to tidal oscillations of water levels in adjacent open water bodies. The focus is on beach hydrodynamics, but potential applications concern, more generally, time varying and oscillating water levels in coupled systems involving subsurface / open water interactions (natural and artificial beaches, harbor dykes, earth dams, river banks, estuaries). The tidal forcing of groundwater is represented and modeled (both experimentally and numerically) by quasi-static oscillations of water levels in an open water reservoir connected to the porous medium. Specifically, we focus on vertical water movements forced by an oscillating pressure imposed at the bottom of a soil column. Experimentally, a rotating tide machine is used to achieve this forcing. Overall, we use three types of methods (experimental, numerical, analytical) to study the vertical motion of the groundwater table and the unsaturated flow above it, taking into account the vertical head drop in the saturated zone as well as capillary pressure gradients in the unsaturated zone. Laboratory experiments are conducted on vertical sand columns, with a tide machine to force water table oscillations, and with porous cup tensiometers to measure both positive pressures and suctions along the column (among other measurement methods). Numerical simulations of oscillatory water flow are implemented with the BIGFLOW 3D code (implicit finite volumes, with conjugate gradients for the matrix solver and modified Picard iterations for the nonlinear problem). In addition, an automatic calibration based on a genetic optimization algorithm is implemented for a given tidal frequency, to obtain the hydrodynamic parameters of the experimental soil. Calibrated simulations are then compared to experimental results for other non calibrated frequencies. Finally, a family of quasi-analytical multi-front solutions is developed for the tidal oscillation problem, as an extension of the Green-Ampt piston flow approximation, leading to nonlinear, non-autonomous systems of Ordinary Differential Equations with initial conditions (dynamical systems). The multi-front solutions are tested by comparing them with a refined finite volume solution of the Richards equation. Multi-front solutions are at least 100 times faster, and the match is quite good even for a loamy soil with strong capillary effects (the number of fronts required is small, no more than N≈ to 20 at most). A large set of multi-front simulations is then produced in order to analyze water table and flux fluctuations for a broad range of forcing frequencies. The results, analyzed in terms of means and amplitudes of hydrodynamic variables, indicate the existence, for each soil, of a characteristic frequency separating low frequency / high frequency flow regimes in the porous system
24
Zaghlool, Baher SalahElDeen Othman Ahmed. "Behaviour of three-dimensional concrete structures under concurrent orthogonal seismic excitations." Thesis, University of Canterbury. Civil Engineering, 2007. http://hdl.handle.net/10092/1177.
Full textAbstract:
This thesis is a study into the response and seismic safety of three-dimensional multi-storey concrete structures under concurrent orthogonal seismic excitations. It employs the nonlinear time-history method as its analysis tools. Time-history analyses rely heavily on their utilised earthquake records. Accordingly, this study examines the different approaches of selecting earthquake suites and develops a methodology of selecting representative earthquake scenarios. This methodology is credibly implemented in selecting a far- and a near field suites representative of the New Zealand seismic hazard. The study investigates the response of 6-, 9- and 12-storey concrete structures of different n-X-bays × m-Y-bays. Bidirectional responses of these considered structures are examined and consequently the current combination rules are scrutinised. Consequently this study strongly recommends the use of the 40-percent combination rule in lieu of the widely used 30-percent rule; and the use of time-history analysis in lieu of quasi/equivalent static and response modal analysis methods to avoid their strong dependence on combination rules. An intensive study is conducted employing the incremental dynamic analysis (IDA) technique to investigate structural demands of interstorey drifts, lateral storey drifts and storey accelerations. The study utilises the developed far-field suite and identifies the 50th and 90th percentile demands. Hence it provides easy-to-use expressions to facilitate rapid calculation of the structural demands and the effects of biaxial interactions. An implementation into the Demand and Capacity Factor Design (DCFD) format is presented that infers confidence in the performance levels of the considered structures. The study also draws attention to the importance of considering storey accelerations as their storey values reach as high as 10 × PGA. A sensitivity study is conducted by repeating the IDA investigation while using the developed near-field suite. Subsequently a comparison between the near- and the far-field results is conducted. The results were markedly similar albeit of less magnitudes until the (seismic hazard) intensity measure IM = Sa(T₁) = 0.4g when the near-field results show sudden flat large increase in demands suggesting a brittle collapse. This is attributed to the higher content of the higher mode frequencies contained in near-field ground motions. Finally, the study examines the (vectorial) radial horizontal shear demands in columns and beam-column joints of the previous far- and near-field studies. The combined radial shear demands in corner, edge and internal columns and joints are evaluated that roughly show a square-root proportional relationship with IM that exhibit somewhat brittle failure at IM ≥ 0.35g. Shears demands in the (4-way) internal columns and the (2-way) corner joints show highest magnitude in their respective class. The results suggest transverse joint shear reinforcement of 1.5, 1.0 and 0.5 of the longitudinal reinforcement of the neighbouring beam respectively for corner, edge and internal joints. An implementation of a proposed practical (and simpler) DCFD format shows satisfactory confidence in columns performance in shear up to IM = 0.35g, conversely to joints unsatisfactory performance in shear at the onset of inelastic behaviour (IM > 0.05g).
25
Assaad, Bassel. "Contribution à la prise en compte des aspects thermiques des machines électriques dans un environnement mécatronique." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2251/document.
Full textAbstract:
Les machines électriques jouent un rôle très important dans la conversion d'énergie dans plusieurs applications et domaines. Les contraintes thermiques jouent ainsi un rôle indispensable dans la conception des machines électriques de plus en plus petites et performantes. En effet, la performance des machines électriques est limitée par les températures maximales admissibles dans certaines zones critiques telles que le bobinage, les aimants permanents et les roulements. Deux approches principales peuvent être utilisées pour étudier le comportement thermique de la machine: la méthode nodale ou le circuit à constantes localisées ou les modèles numériques. Dans notre étude, nous proposons d'appliquer la méthode nodale sur une machine électrique intégrée dans un environnement mécatronique complexe. Le modèle thermique développé de la machine est ainsi présenté avec ses différents éléments. En effet, un modèle précis dépend fortement de plusieurs paramètres thermiques tels que les coefficients d'échange convectif, les conductances de contact, les conductivités équivalentes du bobinage, et autres paramètres. En conséquence, des techniques d'analyse de sensibilité sont ensuite appliquées sur le modèle thermique pour identifier les paramètres d'influence significative sur les températures de la machine ainsi que pour la réduction de ce modèle. Ensuite, nous appliquons deux méthodologies d'identification des paramètres thermiques incertains sont développées et appliquées afin de recaler le modèle thermique de la machine. Cette étape permet la validation de ce modèle par rapport à des mesures thermiques sur une machine synchrone à aimants permanents internes installée sur un banc de caractérisation de machine électriques. Finalement, nous intégrons le modèle recalé dans une approche système mécatronique comportant les lois de commande de la machine ainsi que son convertisseur. Ceci permettra ainsi d'étudier l'influence de la température d'une machine électrique sur le système mécatronique completElectric machines play an important role in power conversion in several applications and fields. With the increasing demand for designing lighter and more efficient machines and optimizing the existing structures, thermal analysis becomes a necessary; in fact, the performance of electric machines islimited by the allowable temperatures in many critical components like windings, permanent magnetsand bearings. Two main approaches can be employed in order to study the machine thermal behavior : the lumped parameter thermal network (LPTN) or numerical models. Considering low-computationtime-consuming and the possibility to be integrated in a mechatronics system design, the LPTN method is considered in our study. The latter is mainly applied on electric machine integrated in a complex mechatronics environment. The thermal network is presented along with the definition of the principal elements constituting this network. In fact, an accurate and reliable network strongly depends on many critical parameters like heat transfer coefficients, interface gaps, impregnation goodness, among others. For this reason, different sensitivity analysis techniques are carried out in order to, first, identify the significance of uncertainties in the evaluation of these parameters on machine temperatures and second, to reduce the thermal network. Next, we propose two optimization algorithm-based identification methodologies in order to calibrate results of the thermal network with measured temperatures obtained from a test-bench of a permanent magnet based integrated starter-generator machine. The calibrated model is then integrated in a mechatronics system consisting of an electric model of the electric machine, along with its control strategy and the power converter. This final study allows us to evaluate the impact of the machine temperature rise on the mechatronic system
26
Ke, Ssu-ju, and 柯思如. "Optimization of Multi-Response Using DOE and Dual Response Surface Method." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/86066032882896047480.
Full textAbstract:
碩士國立交通大學
工業工程與管理學系
98
Design of experiments（DOE）and Taguchi methods are often applied in industry to develop new product or improve the process. Due to the product design becomes increasingly complicated, more than one quality characteristic must be simultaneously optimized to improve the product quality. However, DOE and Taguchi method can only deal with optimizing single-response problem. Consequently, developing a procedure to simultaneously optimize multiple quality characteristics becomes an important issue in. Most of the literatures of optimizing multi-response problems are for Taguchi’s experiments. Furthermore, some studies indicate that optimization of DOE is more effective than Taguchi’s method. The purpose of this study is to devolop a method of finding the optimal parameter-setting of a process or product with multi-response using DOE, Grey Relation Analysis(GRA) and Dual Response Surface Methodology（DRSM）. Finally, two real cases from a semiconductor factory in Taiwan are utilized to verify the effectiveness of the proposed procedure.
27
Yang, chao-yu, and 楊昭瑜. "Multi-response optimization of a new adsorbent using response surface methodology." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/52259956950905342076.
Full textAbstract:
碩士淡江大學
水資源及環境工程學系碩士班
98
Most adsorbents based on iron oxides are available as fine powders or are generated in-situ in aqueous suspension as hydroxide floc or gel, making separation of these adsorbents from treated liquid very difficult. Recently, several researchers have developed techniques for coating iron oxide onto the surface of substrates to overcome the problem of solid-liquid separation. However, the iron content on the coated substrates is very low. Instead of using coating techniques, in this study iron-rich chitosan-iron oxide composites were formed by mixing chitosan and ferric chloride solution with alkaline solution. The shape, solubility of adsorbent and ratio of chitosan and iron oxides affect Arsenic (As(V)) removal efficiency. According to literatures, five factors, namely concentration of chitosan, Fe, and NaOH, height of the needle head, and the cross-linking reaction, might affect the formation of chitosan-iron oxide composites and As(V) removal efficiency were tested, and their significance were screened experimentally according to fractional factorial design. Subsequently, the selected influential variables (Fe and chitosan concentrations) were included in the regression models of Aspect ratio (%), Solubility of Fe (%), and As removal efficiency (%) which were determined by CCD and RSM. The formula for making ‘the best’ adsorbent was determined based on Derringer’s desirability function including Aspect ratio, Solubility of Fe, and As Removal efficiency. Adsorption of arsenic (V) by adsorbent produced using ‘the best’ formula was studied at pH 7.0 under equilibrium and dynamic conditions. The monolayer adsorption capacity obtained from fitting experimental data with Langmuir model was 11.72 mg/g, and the time to reach equilibrium is about 5 hours, indicating a specific adsorption occurring between the arsenic species and the surface of the adsorbent. SEM analysis reveals that the surface of adsorbent was smooth.
28
Gaun-Ru, Wang, and 王冠儒. "The Application of a Dual Response Surface Approach on Multi- Response Optimizing Problems." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/06716027263195581236.
Full textAbstract:
碩士國立臺灣科技大學
工業管理系
88
In the 1980’s, Dr. Taguchi proposed his approach to using statistically design experiments on off-line quality control. Now, Taguchi method has been widely implemented in industry quality control. But, most applications of Taguchi method have been concerned with the optimization of a single-response process. However, due to the increasing complexity of the design of a product, most quality of a product depends on more than one quality characteristic. Hence, this study proposes a procedure to optimize multi-response simultaneously. This study applies dual response surface system to depart from the mean and the standard deviation of a quality characteristic, instead of using SN-ratio, and then combining the desirability function to solve multi-response problems simultaneously. At last, the effectiveness and the usefulness of the proposed procedure is demonstrated by a experiment of chemistry engineering.
29
Li, Bai-Chuan, and 李百川. "Optimizing Multi-Response Problems in Mixture Experiments By Using Dual Response Surface Analysis." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/66498727117484142029.
Full textAbstract:
碩士國立交通大學
工業工程與管理系所
93
Design of experiments is often applied in industry to develop new product. However, in some chemical or material experiments, responses are usually affected by factor’s (or component’s) proportion rather than the factor’s quantity. Such experiments are called mixture experiments. Because the proportions of components have to be added to 100%, the dimension of solutions for the optimal factor-quantity combination using the response surface method (RSM) is less than that of the conventional designed experiments. In addition, due to the product design becomes increasingly complicated, more than one quality characteristic must be simultaneously optimized to improve the product quality. Although several procedures for optimizing multi-response process have been developed in recent years, they are appropriate only for the conventional experiments. Only few cases were studied for mixture designs with single response. When more than one response is to be optimized in mixture design, engineers usually determine the optimal component’s proportions from their experiences. However, it is very difficult to decide the optimum component’s proportions. Therefore, this study proposes an optimizing procedure to resolve multi-response problem for mixture designs. This study uses the Grey Multiple Attribute Decision Making (GMADM) or Principle Component Analysis (PCA) to integrate multiple responses into one component’s proportions index, and then develops a procedure for optimizing the composite quality index. Besides, product’s competitiveness is also determined by its manufacturing cost. This study further develops a procedure for obtaining the optimal proportion combination with the manufacture cost. A real case of rubber bowl experiment from a Taiwan’s company is utilized illustrate the effectiveness of the proposed procedure.
30
Huang, Guo Zhan, and 黃國展. "Bayesian estimation of stationary point of a two factor response surface." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/45285925000590187442.
Full text
31
Chen, Chih-Chien, and 陳志堅. "Quality Improvement of Multi-response Processes Using VIKOR and Factor Analysis." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/40315988533114428986.
Full textAbstract:
博士國立交通大學
工業工程與管理系所
94
Multiple quality characteristics should be simultaneously considered to enhance the product quality and reduce the cost as the modern products or process designs become complex increasingly. Therefore, engineers optimize the multi-response processes using Design of Experiment (DOE) or Taguchi method in the design stage and monitor the processes using multivariate control charts to assure the multivariate processes are in control. Although several procedures for optimizing multi-response processes have been developed in recent years, the associated quality measurement indices do not consider variations in the relative quality losses of multiple responses. These procedures may therefore result in an optimization in which quality losses associated with a few responses are very small but those associated with others are very large, even if the overall average quality loss is small. As for the multivariate control technique, Hotelling T2 control chart is a popular multivariate control chart in industry. However, the calculation loading of T2 index is large when monitoring variables are larger. Besides, T2 index cannot be calculated if variables number is larger than cases number. It is also hard to detect the out of control situation of process in utilizing the Hotelling T2 control chart when the relationships among process parameters are complex. In this study, we will apply the VlseKriterijumska Optimizacija I Kompromisno Resenje in Serbian, means Multicriteria Optimization and Compromise Solution (VIKOR) method and factor analysis to solve the above problem. Finally three real cases and one simulation case study are utilized to verify the effectiveness of the proposed procedure.
32
Chen, Jiao-Yan, and 陳姣燕. "Optimizing Multi-response Problems in a Dynamic System by Using Dual Response Surface Analysis." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/70670506458374956848.
Full textAbstract:
碩士國立交通大學
工業工程與管理研究所
86
Tanguchi method has been widely implemented in industry for product/puocess improvement. Most of the Taguchi''s applications are focused on the optimization of a single-response in a state system. Optimization of a dynamic system has received more attentions in recent years. Due to the increasing complexity of the product design, more than one quality characteristic must be considered simultaneously to improve the product''s quality. Hence, optimizing multiple responses simultaneously in a dynamic system becomes an importantissue. This study proposes a procedure which utilizing the desirability function and dual response surface analysis to optimize the multi-response problems in a dynamic system. First ,the desirability function is applied to measure the overall measurements of sensitivity and quality variation. Next, the dual response surface analysis is used to obtain a set of possible optimm factor level combiantions. The optimun factor level setting is obtained according to the maximum overall desirability value. Finally, the propsed procedure is illustrated by a biological reduction of ethly acetoacetate process experiment. A comparison between the propsed method, the conventional and other ways of analyzing multi-response problems in a dynamic system are made to verified the effectiveness of the proposed method.
33
Lo, Ming-Huang, and 羅明煌. "Bayes estimate of the single factor quadratic response surface under the noninfmative prior." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/47001337830263587154.
Full text
34
Lin, Wan-Ting, and 林婉婷. "Application of Response Surface Method for Robot Arm’s Multi-Process Capability Analysis." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/67312158631862151478.
Full textAbstract:
碩士國立勤益科技大學
工業工程與管理系
101
Nowadays the talent costs of various industries are rising. Robotic arm is future trend to replace manpower and is one of the options to reduce costs. While industrial use of robotic arm in addition to reduce the production costs, to increase production efficiency, to enhance the quality of external energy to make the operators away from the potentially hazardous work environments, the working environment hazards includes radiation, toxic gases, noise ... etc. Robotic arm is widely used of various industries. In recent years, the robotic arm development is becoming increasingly sophisticated, and it can perform high-complexity and high-precision of the actions, and make the quality improved for the manufactured products. In the manufacturing process, product processing accuracy is essential factor to be considered, especially in the semiconductor industry precision manufacturing that is most important. While the multi-axis robotic arm is working in the long terms, a cumulative or repetitive error values exist that can affect the accuracy of the robotic arms. Some minor errors caused by processing failure and cause the products poor quality. It becomes a widely discussed issue and sustained attention how to improve the accuracy. Currently many ways to improve are the accuracy of the controllers, and the use of the controllers to improve the accuracy will cause the system cost increasing. This study applied engineering robotic arm offset experiments conducted by the obtained experimental data. And using Response Surface Method (RSM) of Box-Behnken Design improved, Cpk values are increased to 1.33, and then show painted on Multi-Process Capability Analysis chart (MPCA). After improvement were offset placement in the process control area within the boundaries of 0.25 and the neural network indicate the state of convergence. Through MPCA chart and convergence plans are to validate the process of robotic arm accuracy, as determined in accordance with standards of process capability and assessment whether mechanical arm with good processing quality capabilities . In this study, analysis methods can provide relevant industries the references as a practical process control evaluation and processing quality improvement.
35
Lin, Chin-Tang, and 林錦堂. "Dynamic Response of Moving Vehicle and Multi-Span Continuous Bridge with An Irregular Surface." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/75938298904601214190.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
92
Abstract This aim of this thesis is to study the dynamic response of the vehicle and the multi-span bridge with irregular surfaces. The vehicle body is modeled as an elastic flexible beam and the bridge is modeled as multi-span continuous elastic flexible beam. The bridge is considered to be a finite length, uniform cross-section beam with an uneven profile, which can be simulated as a random process. Three types of road profiles, such as white noise process, Markov process and the ergodic stationary Gaussian zero mean process, will be discussed in the study. The modal superposition method is used to formulate the equation of motion for the coupled vehicle-bridge system. Accordingly, this equation can be rewritten as a state equation. Finally, the mean value and variance of displacement of the structural system is solved by using the proposed recursive algorithm. The numerical results are compared with those using the Monte Carlo simulation approximation. Examples are presented to study the dynamic deflections with the suspension damping, bridge length and the vehicle velocity respectively, as a parameter.
36
Wu, Chung-Yi, and 吳重毅. "Multi-Objective Optimization Design Using Response Surface Methodology in Permanent Magnet Linear Synchronous Motor." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/77783066758465716026.
Full textAbstract:
碩士國立勤益科技大學
電機工程系
103
This paper aims to multi-objective optimized design of three-phase Permanent Magnet Linear Synchronous Motor (PMLSM). The purpose of this dissertation is to provide use of Response Surface Methodology (RSM) in decreasing its cogging force, and retain its back-electromotive force (back-EMF) and force so as to achieve the multi-objective optimized result. PMLSM have two factors that affect the motor performance. Harmonic components that caused commutation ripple-force by the impressed voltage and current, between the slot and the stator magnet are generating cogging-force, respectively. These two factors are the main cause of the ripple-force. The driver is limited by commutation rippler-force of the performance. The cogging force can use new magnet types to improve. This paper uses the Maxwell 2D Finite Element Method electromagnetic field simulation analysis software developed by Ansoft (U.S.). Through the comparison between simulation results and prototypes, and evaluate the performance of PMLSM. Focuses on the optimization design of permanent magnet, in the design of permanent magnet, the variable thickness of permanent magnet (Δhm), maximum thickness of permanent magnet (Δm), harmonic amplitude and magnet width were considered for optimal design of magnet. These parameters affect on the motor can not be learn directly from the formula, so must match the response surface method of regression model optimization mode, find the most suitable combination. In the end, analyze and comparison. And then, use anylsis methods to compare, and prove effective is better.
37
Lee, Chang Cha, and 李長洽. "A Study of the Bayesian Estimation of the Stationary Point of Single Factor Quadratic Response Surface." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/91597397214303533460.
Full textAbstract:
碩士中原大學
工業工程研究所
81
The stationary point of a response surface function bears the location and magnitude coordinates of the maximum or minimum response value. In the context of industrial applications, the precise determination of the location parameter implies achievment of an optimal process settings rendering an optimal yield and minimal cost. In this research, we systematically consider nine different combinations of priors. It covers the range from completely non- informative, to partially informative and comprehensively informative, we develop the posterior distributions for the parameters of interest. We evaluate the marginal posterior distribution of concerned parameters through characteristic model. We use a set of observations and explore their point estimates and related statistics, namely posterior mean, mode, variance, and HPD. Both numerical and Gibbs sampling methods are used. We also carry out a robust analysis over different combinations of priors and also different hyperparameters setup. It's found that the priors which have thick tails or greater variance is more robust than the others. Besides, we compare the computing time between traditional numerical method and Gibbs sampling method. In acceptable precision, the computing time of numerical method is ten times of Gibbs sampling. It is therefore justified that the Gibbs sampling can be used as a good alternative of numerical method.
38
Sakib, Nazmus. "Response of asphalt matrix under multi-axial stress state." Thesis, 2014. http://hdl.handle.net/2152/25860.
Full textAbstract:
The pavement system is subjected to complex stress states under vehicular loading. A combination of axial and shear stress has been identified as a potential cause of top down cracking (or more precisely near surface cracking) in asphalt surface. Therefore, in terms of modeling the material response a pertinent question is whether the typical one-dimensional viscoelastic properties of the material are affected by a multi-axial stress state. Such changes are referred to as interaction non-linearity. The objective of this study was to evaluate whether or not asphalt composites are susceptible to such interaction effects. The study was conducted using fine aggregate matrix (FAM), which comprises graded sand and asphalt binder.
To provide multi-modal loading, the rectangular prismatic FAM specimens were used with the Arcan apparatus. This apparatus ensures low bending stress and offers adjustments in the setup to provide different proportions of axial and shear stress. Finite element modeling was done to evaluate the stress state for different orientations of the sample in the Arcan apparatus. For measurement of strain, the study used digital image correlation (DIC), which is an optical, non-contact measurement technology. The strain thus measured was used to compute shear compliance. Fitting parameters of the shear compliances were estimated for power-law and Prony series for different loading orientations. When compared, the measured shear compliances do not show perceivable variation with respect to different proportion of axial stress applied in conjunction. However, further testing with different temperatures and other magnitudes of shear stress is necessary. This study is the first step to allow modeling of stress and crack propagation behavior near the pavement surface where complex stress state is present.text
39
Huang, Chun-shin, and 黃雋心. "Application of Grey Relational Analysis,Taguchi's Method and Response Surface Methodology in Multi-objective Quality Characterization Optimization." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/9rjw48.
Full textAbstract:
碩士國立高雄大學
亞太工商管理學系碩士班
97
Taguchi Method’s Robust Design has been applied in a various range of industrial applications. However, the major part only aims at the question of single performance characteristics optimization. More than one quality characteristics must be simultaneously considered to effectively improve the product quality due to the increasing complexity of product design. Optimizing each quality characteristic separately may not result the optimality for the entire production. More often, considering one quality characteristic may conflict with the other. The more the number of the performance characteristics, the stronger the correlation of them. It also brings the engineer the difficulties of resolving the performance characteristics conflict. This article undertakes the Optimization of multiple quality characteristics using the combination of Taguchi Method and Grey Relational Analysis. If the factorial level belongs to the continuous factor, this work will find the best setup according to the Response Surface Methodology to confirm the valuable combination. In order to show the effectiveness and practicality of the proposed algorithm, this article uses the two cases – Substrate Laser Displacement Measurement and Optimal Coating of Photoresists of LCD process respectively. The results show that this method can find the best production process parameter level combination of the two processes. Demonstrating the effectiveness of the research, helps the company to improve the quality of product effectively.
40
Chen, Chien-Chih, and 陳建志. "Combine Neural Network and Response Surface Method in Control of a Multi-Axle-Steering Tractor and Trailer." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/82196957181897939674.
Full textAbstract:
碩士國立屏東科技大學
機械工程系所
96
The purpose of this content was studying The controller of a multi-axle-steering tractor and trailer that analyzed effects of a vehicle’s roadability which aimed the vehicle’s changes at loading, high and low speedy turning and other parameters. The tractor-full trailer adopted was formed by a tractor and a trailer what both had the front axles that were able to make turning different form the way of traditional tractor-full trailer. According to the consequence of investigating a four-wheel-turning compact, deriving firstly the multi-axle-steering model, and then proceeding the derivation of the optimal control method which used the trained artificial neural network to make the parameter of the controller adjust within the range of the robust stability for assuring the robust stability of a vehicle’s controller and combining the response surface methodology to request the best solution of the controller when the control factors or parameters stated above changed. At last, applying MATLAB software to proceed simulation analysis. The initial studying result showed that the automatic adjusted robust controller could shorten in short time the error caused by variables, and it adjusted to qualify the request from the system. Comparing this controller with the system of simplified control of the optimal control method, the error of the system became 8.7375 from 9.7589, it improved 10.5%.
41
Shih, Chieh-Fang, and 石傑方. "Research on Parameter Optimization of a Real- time Target Recognition System for a Multi-layer Mediums Penetration－Using the Response Surface Method." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/jhh6xf.
Full textAbstract:
碩士國立臺灣科技大學
高分子系
94
In order to find the best combination of the recognition rate and recognition time, we apply the central composite design of the Response Surface Method（RSM）of experimental design to analyze two factors, “window size” and “recognition period”, and use the Minimum distance classifier which applied in the digital signal processor (DSP) of a penetrator to recognize the features of a penetrating accelerometer.
42
Chu, Chung-Wei, and 朱仲威. "Response surface analysis and simulation method in solving a multi-objective push/pull boundary strategy—A case study on TFT-LCD backend process." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/68650882916046595746.
Full textAbstract:
碩士國立成功大學
製造工程研究所碩博士班
95
The demand for flat-screen monitor panels increases each day. With the help of the Taiwanese Government’s heavy input and guidance, the Taiwanese flat panel industry flourishes. However, the TFT industry faces the problems of mass production and high material cost, as well as high demand variability, thus a different production model is required as opposed to the traditional way of low-variety high-volume production. The traditional production process involves either the push system or the pull system. Although the push system has the advantage of high service level, it has the disadvantage of pressure from possible high inventory cost. On the contrary, the pull system could minimise the risk of inventory, but it has the aspect of prolonged lead time which could compromise the level of service. This study investigated the push/pull system which combined the advantages of both the push system and the pull system, a solution to the conflict between service level and inventory cost. With the approach of combining the system Simulation and response surface analysis, this study aimed to investigate, under situations of stochastic process and multiple production lines, a suitable control factor and its related push/pull boundary positions. By doing so, a suitable framework for the push/pull system could be established, thus the goal to lower overall inventory cost and improvement of service could be accomplished. A case study of a TFT-LCD factory is included to test the theories investigated in this study.
43
Amaral, Joana Bastos. "Multi element removal and recovery using living macroalgae: data treatment influence on results interpretation." Master's thesis, 2020. http://hdl.handle.net/10773/29212.
Full textAbstract:
Water contamination is not a new problem today, as the presence of potentially toxic elements in waters is a known reality throughout the world. However, technological development and the widespread use of electrical and electronic equipment, which have been increasing each year, have contributed to the emergence of new contamination sources, such as electronic waste, and new contaminants, such as rare earth elements. The discharge of these economically valuable and technology critical elements in aquatic ecosystems is increasingly frequent, requiring actions that reduce or eliminate risks to ecosystems and to humans.
This study evaluates the potential use of living macroalgae for the removal of rare earth elements (La, Dy, Eu, Nd and Gd) and potentially toxic elements (Hg and Pb) from waters in environmentally relevant concentrations. It is also assessed the influence that different approaches can have on results interpretation, which are based on statistical foundations, and on physical, chemical, and biological aspects, inherent to multidisciplinary studies like the present one.
Macroalgae are already known to be efficient in removing potentially toxic elements from water; however, can living macroalgae be the new future to solve both the water crisis as well as the crisis of rare earth elements as a raw material scarcity?
With the present study, it was possible to determine, using both a cluster analysis and a linear discriminant analysis, that the rare earths elements in study had similar removal behaviours, however different from the other two potentially toxic elements in study, Pb and Hg. The latter being the most well removed element having possible predicted removal percentages of 97 % with only 24 hours of exposure. Nevertheless, through a surface response methodology, it was possible to determine the optimal conditions for these elements’ removal from multi contaminated waters, using a living macroalgae (Ulva lactuca). Hence, after 72 hours it would be possible to obtain predicted removals above 70 % for all elements in study at a salinity of 21 ± 9, an initial contaminant concentration of 1.6 ± 0.9 μmol/L and a macroalgae dosage of 3.6 ± 2.0 g/L.A contaminação de águas não é um problema novo na sociedade atual, sendo a presença de elementos potencialmente tóxicos em meios aquáticos uma realidade conhecida em todo o mundo. No entanto, o desenvolvimento tecnológico e o uso generalizado de equipamentos elétricos e eletrónicos, que têm vindo a aumentar a cada ano, contribuíram para o surgimento de novas fontes de contaminação, como o lixo eletrônico, e de novos contaminantes, como os elementos terras raras. A descarga destes elementos, economicamente valiosos e críticos para a tecnologia, nos ecossistemas aquáticos é cada vez mais frequente, exigindo-se ações que diminuam ou eliminem os riscos para os ecossistemas e para o ser humano. Este estudo avalia a potencial utilização de macroalgas vivas na remoção de elementos terras raras (La, Dy, Eu, Nd e Gd) e de elementos potencialmente tóxicos (Hg e Pb) em misturas com concentrações ambientalmente relevantes. É também avaliada a influência que abordagens distintas podem ter na interpretação dos resultados, as quais são assentes em fundamentos estatísticos, e em aspetos físicos, químicos e biológicos, inerentes a estudos multidisciplinares como o presente. As macroalgas já são conhecidas por serem eficientes na remoção de elementos potencialmente tóxicos da água; no entanto, poderão as macroalgas vivas ser o novo futuro para resolver simultaneamente a crise da água e a crise da escassez de elementos terras raras como matéria-prima? Com este estudo foi possível determinar, usando uma análise de cluster e uma análise discriminante linear, que os elementos terras raras tinham comportamentos de remoção semelhantes, porém diferentes dos outros dois elementos potencialmente tóxicos em estudo, Pb e Hg. Sendo o último o elemento melhor removido, tendo possíveis percentagens de remoção previstas de 97% com apenas 24 horas de exposição. No entanto, por meio de uma metodologia de resposta de superfície, foi possível determinar as condições ideais na remoção destes elementos de águas contaminadas usando macroalgas vivas (Ulva lactuca). Assim, após 72 horas, seria possível obter remoções previstas acima de 70% para todos os elementos em estudo a uma salinidade de 21 ± 9, uma concentração inicial dos contaminantes de 1,6 ± 0,9 μmol/L e uma dosagem de macroalgas de 3,6 ± 2,0 g/L.
Mestrado em Química
44
Muthu, Krishnan M. "Study Of Multiple Asperity Sliding Contacts." Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2538.
Full textAbstract:
Surfaces are rough, unless special care is taken to make them atomically smooth. Roughness exists at all scales, and any surface-producing operation affects the roughness in certain degrees, specific to the production process. When two surfaces are brought close to each other, contact is established at many isolated locations. The number and size of these contact islands depend on the applied load, material properties of the surfaces and the nature of roughness. These contact islands affect the tribological properties of the contacting surfaces. The real contact area, which is the sum total of the area of contacting islands, is much smaller than the apparent contact area dictated by the macroscopic geometry of the contacting surfaces. Since the total load is supported by these contact islands, the local contact pressure will be very high, and dependent on the local microscopic geometry of the roughness. Thus understanding the deformation behaviour of the rough surfaces will lead to better understanding of friction and wear properties of the surfaces. In this work, the interaction of these contact islands with each other is studied when two surfaces are in contact and sliding past each other.
Asperities can be thought of as basic units of roughness. The geometry and the distribution of heights of asperities can be used to define the roughness. For example, one of the earliest models of roughness is that of hemispherical asperities carrying smaller hemispherical asperities on their back, which in turn carry smaller asperities, and soon. In the present study the asperities are assumed to be of uniform size, shape and distribution. Normal and tangential loading response of these asperities with a rigid indenter is studied through elastic-plastic plane strain finite element studies.
As a rigid indenter is loaded onto a surface with a regular array of identical asperities, initial contact is established at a single asperity. The plastic zone is initially confined within the asperity. When the load is increased ,the elastic-plastic boundary moves towards the free surface of the asperity, and the contact pressure decreases. The geometry and spacing are determined when the neighbouring asperities come into contact. The plastic zone in these asperities is constrained, and hence contact pressure sustained by these asperities is larger. As the indentation progresses, more asperities come into contact in a similar way. If a tangential displacement is now applied to the indenter, the von Mises stress contours shift in the direction of indenter displacement. As the tangential displacement increases, the number of asperities in contact with the indenter decreases gradually before reaching a steady sliding state.
The tangential sliding force experienced by the indenter arises from two components. One is the frictional resistance between the contacting surfaces and the other is due to the plastic deformation of the substrate. If the surface is completely elastic, it has been seen that the sliding force is purely due to the specified friction coefficient. For the smooth surface, as the subsurface makes the transition from purely elastic to confined plastic zone, plasticity breaks out on the free surface, hence the sliding force increases. For surfaces with asperities, even at very small load, the asperities deform plastically and hence the sliding force is considerably higher.
The frictional force is experimentally measured by sliding a spherical indenter on smooth and rough surfaces. These experimental results are qualitatively compared with two dimensional finite element results. It has been observed that for rough surface, sliding force is considerablyhigherthanthesmoothsurface,asisobservedinsimu-lations at lower loads. In contrast to the simulations, the sliding force decreases at higher loads for both the smooth and rough surfaces.
45
Muthu, Krishnan M. "Study Of Multiple Asperity Sliding Contacts." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2538.
Full textAbstract:
Surfaces are rough, unless special care is taken to make them atomically smooth. Roughness exists at all scales, and any surface-producing operation affects the roughness in certain degrees, specific to the production process. When two surfaces are brought close to each other, contact is established at many isolated locations. The number and size of these contact islands depend on the applied load, material properties of the surfaces and the nature of roughness. These contact islands affect the tribological properties of the contacting surfaces. The real contact area, which is the sum total of the area of contacting islands, is much smaller than the apparent contact area dictated by the macroscopic geometry of the contacting surfaces. Since the total load is supported by these contact islands, the local contact pressure will be very high, and dependent on the local microscopic geometry of the roughness. Thus understanding the deformation behaviour of the rough surfaces will lead to better understanding of friction and wear properties of the surfaces. In this work, the interaction of these contact islands with each other is studied when two surfaces are in contact and sliding past each other.
Asperities can be thought of as basic units of roughness. The geometry and the distribution of heights of asperities can be used to define the roughness. For example, one of the earliest models of roughness is that of hemispherical asperities carrying smaller hemispherical asperities on their back, which in turn carry smaller asperities, and soon. In the present study the asperities are assumed to be of uniform size, shape and distribution. Normal and tangential loading response of these asperities with a rigid indenter is studied through elastic-plastic plane strain finite element studies.
As a rigid indenter is loaded onto a surface with a regular array of identical asperities, initial contact is established at a single asperity. The plastic zone is initially confined within the asperity. When the load is increased ,the elastic-plastic boundary moves towards the free surface of the asperity, and the contact pressure decreases. The geometry and spacing are determined when the neighbouring asperities come into contact. The plastic zone in these asperities is constrained, and hence contact pressure sustained by these asperities is larger. As the indentation progresses, more asperities come into contact in a similar way. If a tangential displacement is now applied to the indenter, the von Mises stress contours shift in the direction of indenter displacement. As the tangential displacement increases, the number of asperities in contact with the indenter decreases gradually before reaching a steady sliding state.
The tangential sliding force experienced by the indenter arises from two components. One is the frictional resistance between the contacting surfaces and the other is due to the plastic deformation of the substrate. If the surface is completely elastic, it has been seen that the sliding force is purely due to the specified friction coefficient. For the smooth surface, as the subsurface makes the transition from purely elastic to confined plastic zone, plasticity breaks out on the free surface, hence the sliding force increases. For surfaces with asperities, even at very small load, the asperities deform plastically and hence the sliding force is considerably higher.
The frictional force is experimentally measured by sliding a spherical indenter on smooth and rough surfaces. These experimental results are qualitatively compared with two dimensional finite element results. It has been observed that for rough surface, sliding force is considerablyhigherthanthesmoothsurface,asisobservedinsimu-lations at lower loads. In contrast to the simulations, the sliding force decreases at higher loads for both the smooth and rough surfaces.
46
Abello, Manuel Blanco. "Application of memory-based approach to multi-objective optimisation on dynamic resource-constrained project scheduling with time-varying number of tasks." Thesis, 2014. http://hdl.handle.net/2440/84729.
Full textAbstract:
Many, if not all, manufacturing processes in industry require scheduling activities; such
activities are very important as often they determine the success or failure of some companies.
For example, in wine production, grapes are planted, mature fruits are harvested,
transported and crushed then the juice obtained is placed in tanks, which are managed
during fermentation, and finally the wine is bottle. A schedule can be a solution to a problem
which has several, possibly conflicting objectives, e.g. the mininisation of production
costs and delays while meeting customer-imposed wine delivery times; the problem also
has constraints, e.g. a bottling line cannot be used without being cleaned to process white
wine when it last processed red wine. As can be expected, the problem has variables such
as the number of wine bottles ordered.
The environment (e.g. wine factory) in which the schedule is implemented may change
(e.g. one bottling line breaks down) whereby this schedule becomes infeasible. Consequently,
there could be a need to solve a new scheduling problem to obtain a new schedule
best suited to the new state of the environment. The number of variables in this new
problem may be the same as that of the previous problem. A large proportion of research
effort has been directed towards scheduling problems with a constant number of variables
despite changes in the environments where the problems are set. However, there are
important scheduling problems where the number of variables could vary. For example,
in some models of job-shop scheduling problems there are occurrences of additional rush
jobs and job cancellations.
This thesis deals with one particular class of scheduling problems, each being multi-objective,
resource constrained, and having numbers and values of variables which vary
over time. Various traditional operation research methods as well as a few Artificial
Intelligence-based techniques, such as Multi-Agent Systems and Evolutionary Algorithms
(EA), have been applied to solve this type of problem. In this thesis, a memory-based
EA technique was applied to solve problems from the class. Being memory-based, this
technique utilises the solutions to problems set in previous states of an environment in order to solve a problem set in the current state of this environment.
The memory-based EA technique, referred to as Centroid-Based Adaptation with Random Immigrants (CBAR), is applicable only to solve multi-objective, resource-constrained
problems with a constant number of variables. In this thesis, CBAR is extended to become
applicable to solve all problems from the above-mentioned class. The result of this
extension is a technique referred to as Mapping of Task IDs for CBAR (McBAR).
This thesis investigates the performance, the performance stability over environmental
dynamics, and the efficiency of McBAR for solving various problems from the above class,
legitimises the sub-algorithms that constitute McBAR and extends McBAR to become
proactive (anticipative of future environmental changes).
Compared to the other techniques investigated in this thesis, results showed McBAR
to have the best and most stable performance, and to be most efficient for determining
solutions to problems from the above class. All of the sub-algorithms of McBAR are shown
to be legitimate, while McBAR having been made proactive is shown to be beneficial in
some applications.Thesis (Ph.D.) -- University of Adelaide, School of Computer Science, 2014
47
Nessim, Carolyn. "Development of a multi-gene PCR assay for the prediction of the response to hormone therapy in breast cancer." Thèse, 2013. http://hdl.handle.net/1866/10573.
Full textAbstract:
Deux tiers des cancers du sein expriment des récepteurs hormonaux ostrogéniques (tumeur ER-positive) et la croissance de ces tumeurs est stimulée par l’estrogène. Des traitements adjuvant avec des anti-estrogènes, tel que le Tamoxifen et les Inhibiteurs de l’Aromatase peuvent améliorer la survie des patientes atteinte de cancer du sein. Toutefois la thérapie hormonale n’est pas efficace dans toutes les tumeurs mammaires ER-positives. Les tumeurs peuvent présenter avec une résistance intrinsèque ou acquise au Tamoxifen. Présentement, c’est impossible de prédire quelle patiente va bénéficier ou non du Tamoxifen.
Des études préliminaires du laboratoire de Dr. Mader, ont identifié le niveau d’expression de 20 gènes, qui peuvent prédire la réponse thérapeutique au Tamoxifen (survie sans récidive). Ces marqueurs, identifié en utilisant une analyse bioinformatique de bases de données publiques de profils d’expression des gènes, sont capables de discriminer quelles patientes vont mieux répondre au Tamoxifen.
Le but principal de cette étude est de développer un outil de PCR qui peut évaluer le niveau d’expression de ces 20 gènes prédictif et de tester cette signature de 20 gènes dans une étude rétrospective, en utilisant des tumeurs de cancer du sein en bloc de paraffine, de patients avec une histoire médicale connue. Cet outil aurait donc un impact direct dans la pratique clinique. Des traitements futiles pourraient être éviter et l’indentification de tumeurs ER+ avec peu de chance de répondre à un traitement anti-estrogène amélioré. En conséquence, de la recherche plus appropriée pour les tumeurs résistantes au Tamoxifen, pourront se faire.Two thirds of breast cancers express the estrogen receptor (ER-positive tumours) and estrogens stimulate growth of these tumours. Adjuvant therapy with anti-estrogens such as Tamoxifen and Aromatase Inhibitors has been shown to increase survival in breast cancer patients. This treatment is, however, not successful in all ER-positive tumours. Tumours can present intrinsic or acquired resistance to Tamoxifen. However, it is currently impossible to predict which patient will benefit from Tamoxifen therapy and which will not. Preliminary studies in Dr. Mader’s lab have identified 20 genes whose expression levels in tumours are able to predict the response to Tamoxifen therapy (disease-free survival). These markers, identified using bioinformatics analysis of published gene expression datasets, were able to discriminate patients that would respond best to Tamoxifen from those that did not. The overall purpose of this study is to develop a PCR kit to monitor expression levels of these 20 genes and to test this 20-gene signature in a retrospective study using paraffin-embedded breast cancer tissues of patients with a known medical history. This tool may thus have a direct impact on clinical practice through the development of markers of therapeutic success for treatment with Tamoxifen and possibly Aromatase Inhibitors. Futile treatments would be avoided thus preventing needless side effects, and improved identification of ER+ tumours with a low chance of success to anti-estrogen therapy. This will facilitate research into more appropriate treatments for hormone resistant tumours.