Dissertations / Theses on the topic 'Shape Variable'

To see the other types of publications on this topic, follow the link: Shape Variable.

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Shape Variable.'

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

Sturgill, Derek Joseph. "Variable shape parameter strategies in radial basis funchtion methods." [Huntington, WV : Marshall University Libraries], 2009. http://www.marshall.edu/etd/descript.asp?ref=950.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Bush, Michael T. (Michael Thomas). "Enhanced comfort of seating systems through variable shape and compliance." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41800.

Full text
Abstract:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.
Includes bibliographical references (leaves 73-74).
A new type of seat cushion has been developed. The present use of the cushion is in wheelchair seating, but it may ultimately have application to general seating, particularly in situations where comfort is a significant consideration. The cushion is intended to optimally distribute the interface pressure on the seat of a wheelchair user, as well as to provide an opportunity for active pressure management. The principal goal in developing this cushion is the prevention of pressure sores (decubitis ulcers). The theoretical and design considerations upon which the cushion was developed are presented. Experimental materials data, as well as results of a prototype system, are supplied. A prototype cushion has been produced, and additional work is ongoing. The cushion uses vacuum to manipulate the elastic/collapse properties of open-cell foam; effectively setting a maximum pressure at the human interface. Assuming appropriate auxiliary hardware, pumps, controllers, and sensors it would be appropriate to use this cushion as the basis of an actively controlled seating system.
by Michael T. Bush.
M.S.
APA, Harvard, Vancouver, ISO, and other styles
3

Li, Bingjue. "Variable-Geometry Extrusion Die Synthesis and Morphometric Analysis Via Planar, Shape-Changing Rigid-Body Mechanisms." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1497529085483053.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Bhadane-Deshpande, Minal. "Towards a Shape Memory Alloy Based Variable Stiffness Ankle Foot Orthosis." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333750098.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Salerno, Robert James. "Shape control of high degree-of-freedom Variable Geometry Truss manipulators." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/50089.

Full text
Abstract:
Variable Geometry Trusses (VGT’s) can be used as the fundamental building blocks in constructing long-chain, high degree-of-freedom manipulators. This thesis focuses on the kinematics of two such manipulators. It also illustrates how the concept of shape control can be applied to simplify the computational aspects of controlling these devices. To serve as examples, algorithms are developed for the control of both a thirty degree of freedom planar manipulator and a sixty degree-of-freedom spatial manipulator. Based on a review of the literature, this work appears to be the first attempt to develop real-time, position control strategies for such highly-dexterous manipulators.
Master of Science
incomplete_metadata
APA, Harvard, Vancouver, ISO, and other styles
6

Morris, Asa M. "Generic parallel aerodynamic shape optimisation using efficeint variable fidelity domain element parameterisation." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500430.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Wischt, Rachel Jeanne. "Variable Stiffness and Active Damping Technique for Turbomachinery using Shape Memory Alloys." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1447425764.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Awrejcewicz, Jan, Lidiya Kurpa, and T. Shmatko. "Nonlinear vibration of orthotropic shallow shells of the complex shape with variable thickness." Thesis, Wydawnictwo Politechniki Łódzkiej, 2011. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37115.

Full text
Abstract:
Early R-functions theory [1] combined with variational methods have been applied to linear [2] and nonlinear vibration problems [3,4] of the shallow shells theory of the constant thickness. In the present study, we first apply R-functions theory in order to investigate the geometrically nonlinear vibrations of orthotropic shallow shells of complex shape with variable thickness. Mathematical formulation is made in the framework of classical geometrically nonlinear theory of thin shallow shells. For a discretization of the original system in time, approximation of unknown functions is carried out by using a single mode approach. In order to construct a system of basic functions, the proposed algorithm includes sequence of the linear problems such as finding eigen functions of the linear vibrations of shallow shells with variable thickness and auxiliary tasks of the elasticity theory. The linear problems are solved by the R-functions method. The developed approach allows reducing the original problem to the corresponding problem of solving nonlinear ordinary differential equations (ODEs), whose coefficients are presented in analytical form. In order to solve the obtained system of ODEs the Bubnov-Galerkin method is applied. The proposed algorithm is implemented within an automated system POLE-RL [1]. Numerical examples of large-amplitude flexible vibrations of shallow orthotropic shells with complex shape and variable thickness are introduced demonstrating merits and advantages of the R-functions method. Comparison of the obtained results regarding shells with rectangular plans with the other methods confirms the reliability of the proposed method.
APA, Harvard, Vancouver, ISO, and other styles
9

Mikol, Collin Everett. "Design, Modeling, and Experimental Testing of a Variable Stiffness Structure for Shape Morphing." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523454926569658.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Vesel, Richard Jr. "Optimization of a wind turbine rotor with variable airfoil shape via a genetic algorithm." Connect to resource, 2009. http://hdl.handle.net/1811/44504.

Full text
APA, Harvard, Vancouver, ISO, and other styles
11

Narayanan, Pavanesh. "Sensor-less Control of Shape Memory Alloy Using Artificial Neural Network and Variable Structure Controller." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1416501021.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Giaier, Kevin Stanton. "Designing Shape Changing Mechanisms for Planar and Spatial Applications." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1418043619.

Full text
APA, Harvard, Vancouver, ISO, and other styles
13

Bertram, Anna Verfasser], and Ralf [Akademischer Betreuer] [Zimmermann. "Data-driven variable-fidelity reduced order modeling for efficient vehicle shape optimization / Anna Bertram ; Betreuer: Ralf Zimmermann." Braunschweig : Technische Universität Braunschweig, 2018. http://d-nb.info/1175392154/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Bertram, Anna [Verfasser], and Ralf [Akademischer Betreuer] Zimmermann. "Data-driven variable-fidelity reduced order modeling for efficient vehicle shape optimization / Anna Bertram ; Betreuer: Ralf Zimmermann." Braunschweig : Technische Universität Braunschweig, 2018. http://d-nb.info/1175392154/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
15

USUI, Shin'ichi, Masayuki TANIMOTO, Toshiaki FUJII, Tadahiko KIMOTO, and Hiroshi OHYAMA. "Fractal Image Coding Based on Classified Range Regions." Institute of Electronics, Information and Communication Engineers, 1998. http://hdl.handle.net/2237/14996.

Full text
APA, Harvard, Vancouver, ISO, and other styles
16

Amalraj, Julian Joyce. "Effect of variable material properties on purely thermal phase transformations in shape memory alloy wires, modeling and experiments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0020/MQ47001.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Wilke, Daniel Nicolas. "Approaches to accommodate remeshing in shape optimization." Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/24270.

Full text
Abstract:
This study proposes novel optimization methodologies for the optimization of problems that reveal non-physical step discontinuities. More specifically, it is proposed to use gradient-only techniques that do not use any zeroth order information at all for step discontinuous problems. A step discontinuous problem of note is the shape optimization problem in the presence of remeshing strategies, since changes in mesh topologies may - and normally do - introduce non-physical step discontinuities. These discontinuities may in turn manifest themselves as non-physical local minima in which optimization algorithms may become trapped. Conventional optimization approaches for step discontinuous problems include evolutionary strategies, and design of experiment (DoE) techniques. These conventional approaches typically rely on the exclusive use of zeroth order information to overcome the discontinuities, but are characterized by two important shortcomings: Firstly, the computational demands of zero order methods may be very high, since many function values are in general required. Secondly, the use of zero order information only does not necessarily guarantee that the algorithms will not terminate in highly unfit local minima. In contrast, the methodologies proposed herein use only first order information, rather than only zeroth order information. The motivation for this approach is that associated gradient information in the presence of remeshing remains accurately and uniquely computable, notwithstanding the presence of discontinuities. From a computational effort point of view, a gradient-only approach is of course comparable to conventional gradient based techniques. In addition, the step discontinuities do not manifest themselves as local minima.
Thesis (PhD)--University of Pretoria, 2011.
Mechanical and Aeronautical Engineering
unrestricted
APA, Harvard, Vancouver, ISO, and other styles
18

LIMATOLA, GIOVANNI. "Infrared Linear Renormalons in Collider Processes." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2023. https://hdl.handle.net/10281/402371.

Full text
Abstract:
Al fine di descrivere appropriatamente le osservabili studiate tramite collisori adronici e/o leptonici, risulta cruciale una corretta comprensione delle correzioni non perturbative (che si manifestano come correzioni di potenza), lineari nel rapporto tra una scala di energia non perturbativa e la scala caratteristica del processo. Utilizzando un modello abeliano ricerchiamo tali effetti nella distribuzione in momento trasverso di un bosone Z prodotto con un jet in collisioni adroniche, essendo questa una delle osservabili meglio misurate presso LHC. La presenza delle correzioni non perturbative di cui sopra impedirebbe di raggiungere la precisione sperimentale, anche considerando ordini superiori nello sviluppo perturbativo. Non avendo individuato alcuna correzione di questo tipo tramite tecniche semi numeriche, abbiamo scelto di adottare un approccio più rigoroso dal punto di vista teorico, fornendo una spiegazione attorno al manifestarsi di tali correzioni di potenza. Tale comprensione teorica è stata applicata allo studio delle variabili di shape in annichilazione $e^+e^-$, con particolare attenzione allo studio del C-parametro e del thrust, e ottenendo per tali osservabili una stima delle correzioni non perturbative nella regione dei tre jet per la prima volta. In tale lavoro è stata altresì ottenuta un'espressione fattorizzata per le correzioni non perturbative per alcune osservabili, con un termine dipendente dalla variazione dell'osservabile a seguito dell'emissione di un partone soffice, e un termine costante e universale, proporzionale al cosiddetto Milan factor. Tali osservabili sono ampiamente utilizzate al fine di estrarre valori della costante di interazione forte $\alpha_s$ e costituiscono il contesto ideale al fine di compiere studi di QCD perturbativa. È dunque estremamente importante ottenere stime affidabili delle correzioni non perturbative nell'intera regione di spazio delle fasi rilevante per i fit di $\alpha_s$.
Understanding leading non-perturbative corrections, showing up as linear power corrections, is crucial to properly describe observables both at lepton and hadron colliders. Using an abelian model, we examine these effects for the transverse momentum distribution of a $Z$ boson produced in association with a jet in hadronic collisions, that is one of the cleanest LHC observables, where the presence of leading non-perturbative corrections would spoil the chance to reach the current experimental accuracy, even considering higher orders in the perturbative expansion. As we did not find any such corrections exploiting semi-numerical techniques, we looked for a rigorous field-theoretical derivation of them, and explain under which circumstances linear power corrections can arise. We apply our theoretical understanding to the study of event-shape observables in $e^+e^-$ annihilation, focusing in particular on $C$-parameter and thrust, and obtaining for them an estimate of non-perturbative corrections in the three-jet region for the first time. We also derived a factorisation formula for non-perturbative corrections, with a term describing the change of the shape variable when a soft parton is emitted, and a constant universal factor, proportional to the so-called Milan factor. These observables are routinely used to extract the strong coupling constant $\alpha_s$ and they constitute an environment to test perturbative QCD. It is then extremely important to obtain reliable estimates of non-perturbative corrections in the whole kinematic region relevant for the $\alpha_s$ fits.
APA, Harvard, Vancouver, ISO, and other styles
19

小山, 悟史, Satoshi KOYAMA, 秀幸 畔上, and Hideyuki AZEGAMI. "形状最適化問題の解法における多制約の取り扱い." 日本機械学会, 2003. http://hdl.handle.net/2237/12171.

Full text
APA, Harvard, Vancouver, ISO, and other styles
20

Henke, M., and G. Gerlach. "A multi-layered variable stiffness device based on smart form closure actuators." Sage, 2016. https://tud.qucosa.de/id/qucosa%3A35622.

Full text
Abstract:
This contribution describes the properties and limitations of multi-layered mechanical devices with variable flexural stiffness. Such structures are supposed to be components of new smart, self-sensing and self-controlling composite materials for lightweight constructions. To enable a proper stiffness control, reliable actuators with high actuation capabilities based on smart materials are used. Those actuators are either driven by electroactive polymers (EAPs) or shape memory alloy (SMA) wires. They control the area moment of inertia of the multi-layered bending structures. To change the area moment of inertia and, hence, the flexural stiffness of an multi-layered beam within a wide range, it is necessary to stack as many layers as possible over each other. The fundamental function of this approach is demonstrated with a three-layer stack consisting of three independent layers and four form closure actuators driven by SMAs. This experimental set-up was able to change its bending stiffness k by a factor of 14.6, with a minimum and maximum stiffness of kmin = 0.11 N mm¯¹ and kmax = 1.73 N mm¯¹, respectively. The usage of four independently controllable actuators yields nine independent flexural-stiffness states of the beam. Both analytical and numerical calculations have shown good agreement with the measured stiffness values.
APA, Harvard, Vancouver, ISO, and other styles
21

Heidbuechel, Ingo. "On the Variability of Hydrologic Catchment Response: Inherent and External Controls." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/268575.

Full text
Abstract:
Hydrologic catchment response varies in time. The goal of this dissertation is to investigate how and why it varies and what controls these variations. In order to tackle these questions the first step is to develop a method that permits the capturing of the temporal variation of transit time distributions (TTDs). To this end, the established transfer function-convolution approach using time series of stable water isotopes was modified so that it is now able to determine variable mean transit times (mTTs). The type and the shape parameter of the transfer function also vary in time. We found that antecedent moisture content, saturated hydraulic conductivity, soil depth and subsequent precipitation intensity are all potential controls. We propose a dimensionless number that integrates these controls and relates available storage to incoming and outgoing water fluxes in combination with information on antecedent moisture conditions to predict TTD type and shape. The individual TTDs for every time step produced by this model can be superimposed, summed and normalized to create a classification tool for catchments that is based on its general response behavior to precipitation events: the master transit time distribution. With this model in hand the hydrologic response for three consecutive monsoon seasons in ten nested subcatchments was examined. It was found that the major response controls were changing between the years in accordance with three hydrologic response modes. The mTT correlated most strongly with soil depth in the first year, with hydraulic conductivity in the second year and with curvature in the third year. These variations were produced by differences in precipitation patterns that led to differences in soil saturation and consequently to different dominant flow processes: in the first year most of the water left the catchment via fast flow paths (macropore flow, overland flow), in the second year shallow subsurface flow in the soil matrix was more dominant and in the third year most outflowing water derived from slow base flow. To better predict hydrologic catchment response we propose to apply a dimensionless number to determine the catchment response mode for every time step before selecting the appropriate response control.
APA, Harvard, Vancouver, ISO, and other styles
22

下田, 昌利, Masatoshi Shimoda, 秀幸 畔上, Hideyuki Azegami, 俊明 桜井, and Toshiaki Sakurai. "ホモロガス変形を目的とする連続体の形状決定." 日本機械学会, 1996. http://hdl.handle.net/2237/7244.

Full text
APA, Harvard, Vancouver, ISO, and other styles
23

Rivera, Samuel. "Computational Methods for the Study of Face Perception." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354650651.

Full text
APA, Harvard, Vancouver, ISO, and other styles
24

Sendler, Jochen. "Entwicklung und Gestaltung variabler Bedienelemente für ein Bedien- und Anzeigesystem im Fahrzeug." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1209102371614-58070.

Full text
Abstract:
Angesichts der steigenden Anzahl von Funktionen in Fahrzeugen, insbesondere im Pkw, sind neue Bedien- und Anzeigesysteme notwendig, die eine optimale Bedienbarkeit der Funktionen sicherstellen und die Ablenkung des Fahrers von der Fahraufgabe minimieren. Im Rahmen dieser Arbeit wird dazu der Einsatz variabler Bedienelemente verfolgt, die sich der aktuellen Bedienaufgabe optimal anpassen. Ziel dieser Arbeit ist es insbesondere, Vorgehensweisen und Gestaltungsempfehlungen für variable Beschriftung von Tasten und zentrale Bedienelemente mit variabler Formcodierung für abgesetzte Bedien- und Anzeigesysteme zu erarbeiten. Unter Zuhilfenahme arbeitswissenschaftlicher Methoden wird dafür zunächst die Gestaltung variabler Beschriftung von Tasten untersucht und Empfehlungen für deren Gestaltung abgeleitet. Des Weiteren wird die Entwicklung eines zentralen Bedienelements mit variabler Formcodierung beschrieben. Dazu wird, aufbauend auf bekannten Entwicklungs- und Auswahlverfahren für Bedienelemente, eine Vorgehensweise zur Entwicklung variabler Bedienelemente vorgeschlagen. Das entwickelte variable zentrale Bedienelement wird darüber hinaus hinsichtlich seiner Bedienbarkeit und Ablenkungswirkung bewertet. Aus den Versuchsergebnissen konnten Gestaltungsempfehlungen abgeleitet werden, wie durch ein variables zentrales Bedienelement die Bedienbarkeit von abgesetzten Bedien- und Anzeigesystemen verbessert und die Ablenkungswirkung reduziert werden kann. Die Ergebnisse dieser Arbeit leisten einen Beitrag zur Entwicklung zukünftiger abgesetzter Bedien- und Anzeigesysteme und geben insbesondere Entwicklern und Gestaltern eine Hilfestellung beim Einsatz variabler Bedienelemente.
APA, Harvard, Vancouver, ISO, and other styles
25

Sendler, Jochen. "Entwicklung und Gestaltung variabler Bedienelemente für ein Bedien- und Anzeigesystem im Fahrzeug." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23580.

Full text
Abstract:
Angesichts der steigenden Anzahl von Funktionen in Fahrzeugen, insbesondere im Pkw, sind neue Bedien- und Anzeigesysteme notwendig, die eine optimale Bedienbarkeit der Funktionen sicherstellen und die Ablenkung des Fahrers von der Fahraufgabe minimieren. Im Rahmen dieser Arbeit wird dazu der Einsatz variabler Bedienelemente verfolgt, die sich der aktuellen Bedienaufgabe optimal anpassen. Ziel dieser Arbeit ist es insbesondere, Vorgehensweisen und Gestaltungsempfehlungen für variable Beschriftung von Tasten und zentrale Bedienelemente mit variabler Formcodierung für abgesetzte Bedien- und Anzeigesysteme zu erarbeiten. Unter Zuhilfenahme arbeitswissenschaftlicher Methoden wird dafür zunächst die Gestaltung variabler Beschriftung von Tasten untersucht und Empfehlungen für deren Gestaltung abgeleitet. Des Weiteren wird die Entwicklung eines zentralen Bedienelements mit variabler Formcodierung beschrieben. Dazu wird, aufbauend auf bekannten Entwicklungs- und Auswahlverfahren für Bedienelemente, eine Vorgehensweise zur Entwicklung variabler Bedienelemente vorgeschlagen. Das entwickelte variable zentrale Bedienelement wird darüber hinaus hinsichtlich seiner Bedienbarkeit und Ablenkungswirkung bewertet. Aus den Versuchsergebnissen konnten Gestaltungsempfehlungen abgeleitet werden, wie durch ein variables zentrales Bedienelement die Bedienbarkeit von abgesetzten Bedien- und Anzeigesystemen verbessert und die Ablenkungswirkung reduziert werden kann. Die Ergebnisse dieser Arbeit leisten einen Beitrag zur Entwicklung zukünftiger abgesetzter Bedien- und Anzeigesysteme und geben insbesondere Entwicklern und Gestaltern eine Hilfestellung beim Einsatz variabler Bedienelemente.
APA, Harvard, Vancouver, ISO, and other styles
26

Lo, Hung-Chieh. "Vibration Characteristics of Thin-Walled Noncircular Composite Cylinders." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77207.

Full text
Abstract:
The lowest natural frequencies of thin-walled noncircular fiber-reinforced composite cylinders, specifically cylinders with elliptical cross sections, are investigated. Of interest is the variation of the lowest natural frequency, the so-called fundamental frequency, as a function of wall laminate properties, cross-sectional eccentricity and other cylinder geometric parameters. Both simple and clamped support boundary conditions are investigated. Laminate properties that are uniform with circumferential location and laminate properties that vary with circumferential location, by way of varying laminate fiber angle with circumferential location, are considered. As the radius of curvature of a noncircular cylinder varies with circumferential location, it is logical to consider the influence of circumferentially varying fiber orientation on the fundamental frequency. The analysis for predicting the fundamental frequency is based on Donnell shell theory, linear elastic properties, and the use of Hamilton's Principle in conjunction with the Rayleigh-Ritz technique. By use of a so-called shape factor, the magnitude of cylinder normal displacements are modulated to be larger in the regions of the cross section with the largest radius of curvatures and smaller in the regions with the smallest radius of curvature. The final equations for predicting the fundamental frequency are quite complex, but a series of approximations results in a hierarchy of simpler equations, the simplest being referred to as Lo's approximation. The prediction of the fundamental frequencies is spot checked by comparing the results as predicted by the various levels of approximation with predictions of a shell-based finite element model. Considering uniform laminate properties, comparisons between the developed analysis and the finite element model are good for all levels of simpler equations, and excellent in some cases. The developed analysis is subsequently used for parameter studies. It is found that compared to a circular cylinder of the same circumference and with uniform laminate properties, the fundamental frequency of an elliptical cylinder is always less. Surprisingly, based on the results obtained, it appears that for a given cylinder geometry the fundamental frequency is not particularly sensitive to wall lamination sequence, though the wave number in the circumferential direction of the mode shape associated with the fundamental frequency is sensitive to lamination sequence. Considering cylinders with circumferentially varying fiber orientation, comparisons between the developed analysis and the finite element model for most of the cases studied are good. However, the developed equations are limited since it is difficult to find a set of known functions to describe the deformation of an arbitrary lamination sequence when applying the Rayleigh-Ritz technique. In general, in can be concluded that the effect of varying fiber orientation on the fundamental frequency is much less than the influence of cylinder aspect ratio. It can also be concluded that the developed analysis would be an excellent tool for design purposes, as the calculation of the fundamental frequency is done quickly, and design trade-offs studies would be easy.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
27

Beatton, Douglas Anthony. "The economics of happiness : a lifetime perspective." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/50009/1/Douglas_Beatton_Thesis.pdf.

Full text
Abstract:
The three studies in this thesis focus on happiness and age and seek to contribute to our understanding of happiness change over the lifetime. The first study contributes by offering an explanation for what was evolving to a ‘stylised fact’ in the economics literature, the U-shape of happiness in age. No U-shape is evident if one makes a visual inspection of the age happiness relationship in the German socio-economic panel data, and, it seems counter-intuitive that we just have to wait until we get old to be happy. Eliminating the very young, the very old, and the first timers from the analysis did not explain away regression results supporting the U-shape of happiness in age, but fixed effect analysis did. Analysis revealed found that reverse causality arising from time-invariant individual traits explained the U-shape of happiness in age in the German population, and the results were robust across six econometric methods. Robustness was added to the German fixed effect finding by replicating it with the Australian and the British socio-economic panel data sets. During analysis of the German data an unexpected finding emerged, an exceedingly large negative linear effect of age on happiness in fixed-effect regressions. There is a large self-reported happiness decline by those who remain in the German panel. A similar decline over time was not evident in the Australian or the British data. After testing away age, time and cohort effects, a time-in-panel effect was found. Germans who remain in the panel for longer progressively report lower levels of happiness. Because time-in-panel effects have not been included in happiness regression specifications, our estimates may be biased; perhaps some economics of the happiness studies, that used German panel data, need revisiting. The second study builds upon the fixed-effect finding of the first study and extends our view of lifetime happiness to a cohort little visited by economists, children. Initial analysis extends our view of lifetime happiness beyond adulthood and revealed a happiness decline in adolescent (15 to 23 year-old) Australians that is twice the size of the happiness decline we see in older Australians (75 to 86 yearolds), who we expect to be unhappy due to declining income, failing health and the onset of death. To resolve a difference of opinion in the literature as to whether childhood happiness decreases, increases, or remains flat in age; survey instruments and an Internet-based survey were developed and used to collect data from four hundred 9 to 14 year-old Australian children. Applying the data to a Model of Childhood Happiness revealed that the natural environment life-satisfaction domain factor did not have a significant effect on childhood happiness. However, the children’s school environment and interactions with friends life-satisfaction domain factors explained over half a steep decline in childhood happiness that is three times larger than what we see in older Australians. Adding personality to the model revealed what we expect to see with adults, extraverted children are happier, but unexpectedly, so are conscientious children. With the steep decline in the happiness of young Australians revealed and explanations offered, the third study builds on the time-invariant individual trait finding from the first study by applying the Australian panel data to an Aggregate Model of Average Happiness over the lifetime. The model’s independent variable is the stress that arises from the interaction between personality and the life event shocks that affect individuals and peers throughout their lives. Interestingly, a graphic depiction of the stress in age relationship reveals an inverse U-shape; an inverse U-shape that looks like the opposite of the U-shape of happiness in age we saw in the first study. The stress arising from life event shocks is found to explain much of the change in average happiness over a lifetime. With the policy recommendations of economists potentially invoking unexpected changes in our lives, the ensuing stress and resulting (un)happiness warrant consideration before economists make policy recommendations.
APA, Harvard, Vancouver, ISO, and other styles
28

Ataser, Zafer. "Variable Shaped Detector: A Negative Selection Algorithm." Phd thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615629/index.pdf.

Full text
Abstract:
Artificial Immune Systems (AIS) are class of computational intelligent methods developed based on the principles and processes of the biological immune system. AIS methods are categorized mainly into four types according to the inspired principles and processes of immune system. These categories are clonal selection, negative selection, immune network and danger theory. The approach of negative selection algorithm (NSA) is one of the major AIS models. NSA is a supervised learning algorithm based on the imitation of the T cells maturation process in thymus. In this imitation, detectors are used to mimic the cells, and the process of T cells maturation is simulated to generate detectors. Then, NSA classifies the specified data either as normal (self) data or as anomalous (non-self) data. In this classification task, NSA methods can make two kinds of classification errors: a self data is classified as anomalous, and a non-self data is classified as normal data. In this thesis, a novel negative selection method, variable shaped detector (V-shaped detector), is proposed to increase the classification accuracy, or in other words decreasing classification errors. In V-shaped detector, new approaches are introduced to define self and represent detectors. V-shaped detector uses the combination of Local Outlier Factor (LOF) and kth nearest neighbor (k-NN) to determine a different radius for each self sample, thus it becomes possible to model the self space using self samples and their radii. Besides, the cubic b-spline is proposed to generate a variable shaped detector. In detector representation, the application of cubic spline is meaningful, when the edge points are used. Hence, Edge Detection (ED) algorithm is developed to find the edge points of the given self samples. V-shaped detector was tested using different data sets and compared with the well-known one-class classification method, SVM, and the similar popular negative selection method, NSA with variable-sized detector termed V-detector. The experiments show that the proposed method generates reasonable and comparable results.
APA, Harvard, Vancouver, ISO, and other styles
29

Makem, J. E. "Virtual Net-Shape Forging of Aerofoil Blades - Dimensional Inspection and Shape Sensitivity to Process Variables." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517543.

Full text
APA, Harvard, Vancouver, ISO, and other styles
30

Waugh, Robert George. "Measurement of event shape variables in deep inelastic scattering." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301504.

Full text
APA, Harvard, Vancouver, ISO, and other styles
31

Гладчук, Марта. "Технологічно-конструктивний підхід до проєктування інтерактивних об'єктів зі змінною геометрією в дизайні громадського середовища." Thesis, Київський національний університет технологій та дизайну, 2021. https://er.knutd.edu.ua/handle/123456789/18152.

Full text
Abstract:
Надано результати дослідження технологічно-конструктивного підходу до формоутворення інтерактивних об'єктів дизайну громадського середовища зі змінною геометрією. Описано зв'язок зростання популярності даного підходу з розвитком інформаційних технологій та глобальної медієзації простору життєдіяльності людини в ХХІ столітті. Згідно з поставленим завданням розглянуто основні характеристики технологічно-конструктивного підходу до трансформації, визначено дві основні тенденції його застосування на практиці та наведено конкретні приклади інтерактивних об'єктів зі змінною геометрією для кожної тенденції.
The results of the research of the technological-constructive approach to the construction of interactive objects with variable geometry in public environment design are given. The connection between the growing popularity of this approach and development of information technology and globally spread media in all of the spheres of human life in the XXI century is described. According to the given task, the main characteristics of the technological-constructive approach to transformation are considered, two main trends of its application are identified and specific examples of interactive objects with variable geometry for each trend are given.
APA, Harvard, Vancouver, ISO, and other styles
32

Moravej, Hans. "Vibration-based probabilistic model updating of civil structures using structural health monitoring techniques." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/203653/1/Hans%20Moravej%20Thesis.pdf.

Full text
Abstract:
Information extracted from monitored data is susceptible to uncertainties and not reliable to be used for structural investigations. Finite element model updating (FEMU) is an accredited framework which aims to improve the accuracy of FEMs of real structures. However, FEMU faces barriers to achieving efficiency and addressing uncertainties. This study aims to develop a probabilistic approach based on Modular Bayesian approach (MBA) to address challenges in the application of FEMU. Moreover, this research proposes an integration between MBA and structural reliability analysis to assess the performance of structures during their lifespan. The feasibility of approach is demonstrated on two structures.
APA, Harvard, Vancouver, ISO, and other styles
33

Scott, J. A. "A study of the effect of process variables on the properties of rotationally moulded plastic articles." Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381175.

Full text
APA, Harvard, Vancouver, ISO, and other styles
34

Litherland, Trevis J. "On the limiting shape of random young tableaux for Markovian words." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26607.

Full text
Abstract:
Thesis (Ph.D)--Mathematics, Georgia Institute of Technology, 2009.
Committee Chair: Houdre, Christian; Committee Member: Bakhtin, Yuri; Committee Member: Foley, Robert; Committee Member: Koltchinskii, Vladimir; Committee Member: Lifshitz, Mikhail; Committee Member: Matzinger, Heinrich; Committee Member: Popescu, Ionel. Part of the SMARTech Electronic Thesis and Dissertation Collection.
APA, Harvard, Vancouver, ISO, and other styles
35

Plent, Adrien. "Le capital variable." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM1067.

Full text
Abstract:
Spécificité légale, introduite dans notre droit positif par la loi du 24 juillet 1867, la variabilité du capital social demeure encore de nos jours trop méconnue et devrait, de fait, être érigée au rang des curiosités juridiques. On ne saurait objecter pareil constat en ce que le législateur lui-même ne semble pas lui porter un incommensurable intérêt. En effet, en ce que la variabilité du capital ne résulte que de l’adoption, par une forme sociale de droit commun, d’une simple clause statutaire, ce dernier n’a semble-t-il pas jugé indispensable d’édicter un régime juridique précis et autonome en sa faveur. Aussi, devrait-on y voir ici une renonciation certaine du législateur à la création d’une nouvelle forme sociale ne faisant, en conséquence, que renforcer la singularité dont elle fait l’objet. Toujours est-il que s’arrêter à une telle acception serait réducteur en ce que cette approche desservirait inexorablement la spécificité prévue aux articles L. 231-1 à L. 231-8 du Code de commerce et notamment quant aux nombreuses possibilités qu’elle octroie tant à la société se dotant de la spécificité légale qu’aux associés la composant
Legal specificity, introduced into our substantive law in July 24th, 1867, the variability of the share capital is still too unknown even today and should in fact be raised to the ranks of legal curiosities. We could not object such report in the fact that the legislator does not seem himself to carry him immense one interest. Indeed, the fact that the variability of the capital only results from the adoption, by a social form of common law, of a simple statutory clause, the latter does not see it necessary to enact a specific and independent legal regime in its favour. Also, should the legislator object to the creation of a new social form, it will consequently only reinforce the peculiarity of such objection. The fact remains that to stop such acceptance would be reducing in the fact that this approach would serve inexorably the specificity outlined in articles L. 231-1 in L. 231-8 of the commercial law in particular as for the numerous possibilities that she grants as long to the company being equipped with the legal specificity that to the partners making up her
APA, Harvard, Vancouver, ISO, and other styles
36

McClinchey, Heather Louise. "The effects of changing hoof shape variables analysed with a validated finite element model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0027/MQ51080.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Gillman, Kevin M. "Optimization of Shape, Size, and Topology Design Variables in Trusses with a Genetic Algorithm." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd683.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Shao, Yuan. "Higher order spectra invariants for shape pattern recognition." Ohio : Ohio University, 2000. http://www.ohiolink.edu/etd/view.cgi?ohiou1179949998.

Full text
APA, Harvard, Vancouver, ISO, and other styles
39

Forssén, Cecilia. "Modelling of cavity partial discharges at variable applied frequency." Doctoral thesis, KTH, Elektroteknisk teori och konstruktion, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4756.

Full text
Abstract:
The presence of partial discharges (PD) in high voltage components is generally a sign of defects and degradation in the electrical insulation. To diagnose the condition of high voltage insulation, PD measurements is commonly used. The Variable Frequency Phase Resolved PD Analysis (VF-PRPDA) technique measures PD at variable frequency of the applied voltage. With this technique, the frequency dependence of PD can be utilized to extract more information about the insulation defects than is possible from traditional PD measurements at a single applied frequency. In this thesis the PD process in a disc-shaped cavity is measured and modelled at variable frequency (0.01 - 100 Hz) of the applied voltage. The aim is to interpret the PD frequency dependence in terms of physical conditions at the cavity. The measurements show that the PD process in the cavity is frequency dependent. The PD phase and magnitude distributions, as well as the number of PDs per voltage cycle, change with the varying frequency. Moreover, the PD frequency dependence changes with the applied voltage amplitude, the size of the cavity and the location of the cavity (insulated or electrode bounded). A physical model is presented and used to dynamically simulate the sequence of PDs in the cavity at different applied frequencies. The simulations show that essential features in the measured PD patterns can be reproduced. The PD frequency dependence is interpreted as a variation in influence on the PD activity from the statistical time lag of PD and the charge transport in the cavity surface, at different applied frequencies. The simulation results also show that certain cavity parameters, like the cavity surface conductivity and the rate of electron emission from the cavity surface, change with the time between consecutive PDs, and accordingly with the applied frequency. This effect also contributes to the PD frequency dependence.
QC 20100722
APA, Harvard, Vancouver, ISO, and other styles
40

Dunkel, Caroline Aubrey. "Controlling variables in the transition from a non-organic-rich marine shale to an organic-rich marine shale, Devonian Ohio Shale, north-central Ohio." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1589752994470939.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Kluge, Thomas. "Measurement and QCD analysis of event shape variables in deep inelastic electron proton collisions at HERA." Hamburg : DESY, 2004. http://deposit.d-nb.de/cgi-bin/dokserv?idn=971990387.

Full text
APA, Harvard, Vancouver, ISO, and other styles
42

Riley, Mike J. W. "Evaluating cascade correlation neural networks for surrogate modelling needs and enhancing the Nimrod/O toolkit for multi-objective optimisation." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/6796.

Full text
Abstract:
Engineering design often requires the optimisation of multiple objectives, and becomes significantly more difficult and time consuming when the response surfaces are multimodal, rather than unimodal. A surrogate model, also known as a metamodel, can be used to replace expensive computer simulations, accelerating single and multi-objective optimisation and the exploration of new design concepts. The main research focus of this work is to investigate the use of a neural network surrogate model to improve optimisation of multimodal surfaces. Several significant contributions derive from evaluating the Cascade Correlation neural network as the basis of a surrogate model. The contributions to the neural network community ultimately outnumber those to the optimisation community. The effects of training this surrogate on multimodal test functions are explored. The Cascade Correlation neural network is shown to map poorly such response surfaces. A hypothesis for this weakness is formulated and tested. A new subdivision technique is created that addresses this problem; however, this new technique requires excessively large datasets upon which to train. The primary conclusion of this work is that Cascade Correlation neural networks form an unreliable basis for a surrogate model, despite successes reported in the literature. A further contribution of this work is the enhancement of an open source optimisation toolkit, achieved by the first integration of a truly multi-objective optimisation algorithm.
APA, Harvard, Vancouver, ISO, and other styles
43

Zhang, Xiaodong. "Modeling of materials with internal variables using a thermomechanical approach." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/45355.

Full text
Abstract:
In this thesis, the thermomechanical approach with internal variables has been thoroughly analyzed. This approach is based on the combination of thermodynamic principles and continuum mechanics. Therefore it reflects the physical essence of constitutive behavior of materials. Based on this approach, a one-dimensional constitutive model for the two-way shape memory effect and a one-dimensional constitutive model for piezoceramics have been developed, respectively. In modeling the two-way shape memory effect, a residual stress σre is introduced as a controlling parameter for the two-way shape memory effect. A further refinement of the transformation kinetics expression for two-way shape memory is derived. It is demonstrated that the material parameters required by this model can be calculated or measured using a standard materials testing apparatus. A numerical study is conducted and the effectiveness of this model is verified. In the constitutive modeling of piezoceramics, a new internal state variable is introduced to relate the macroscopic behavior of a piezoceramic with its micro-properties. A phenomenological formulation of polarization reversal is proposed, and then a fully-coupled thermo-electro-mechanical model is developed. It is shown that the theory developed can describe the electromechanical behavior of piezoceramics well.
Master of Science
APA, Harvard, Vancouver, ISO, and other styles
44

Chan, Ching Yee. "Active fund management and crosssectional variance of returns." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/29434.

Full text
Abstract:
In active portfolio management, fund managers seek to follow an investment strategy with the objective of outperforming an investment benchmark index. Opportunities to outperform a benchmark in active fund management is made possible through crosssectional dispersion of returns in the market. It is cross-sectional volatility of returns that allows fund managers to identify changing trends in market relationships and to take advantage of market opportunities.Quarterly active share and active return data of Domestic General Equity funds was used to determine whether the level of active share and active return has a correlation with volatility measures such as cross-sectional variance of returns or the South African Volatility Index (SAVI). The actively-managed funds’ outperformance of the benchmark index during periods of differing cross-sectional variance was also looked at. Lastly, the possibility of whether market volatility can be used to inform fund investment decisions was also examined.The findings in this study are that there is no significant relationship between the crosssectional variance of returns, active share and active returns. In measuring fund performance in times of differing cross-sectional dispersion and breaking the analysis period into such intervals rather than as a continuous time series, active funds outperform the benchmark index during periods of low and moderate cross-sectional variance. The SAVI can be used as a fairly accurate and readily available approximation of cross-sectional variance.
Dissertation (MBA)--University of Pretoria, 2012.
Gordon Institute of Business Science (GIBS)
unrestricted
APA, Harvard, Vancouver, ISO, and other styles
45

Ogden, Lillie. "Exploring Opportunities for Novel Electricity Trading Strategies within a Virtual Power Plant in the European Power Market : New Possibilities in Power Trading Due to the Increased Share of Variable Renewable Energy." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277841.

Full text
Abstract:
This report explores the impacts of variable renewable energy (VRE) on power trading in the European wholesale electricity market. The intricate operation of a typical power exchange in Europe is accompanied by an equally complex balancing system. The increasing amount of VRE in the power system, such as wind and solar power, has far-reaching impacts for power traders in both this electricity market and the corresponding balancing system. As a result, the electricity market is evolving in unprecedented ways and new participants are entering the playing field to capitalize on the changing dynamics caused by VRE generators. One novel participant, the virtual power plant (VPP), possesses an advantage over other market participants by aggregating VRE generators with controllable renewable energy generators, like biogas and hydro plants, into one entity. This allows the VPP to both gain access to live VRE production data that larger plants don’t have, which it then utilizes to remotely dispatch various subpools of assets, and to provide balancing services to the grid. Subsequently, VPPs are able to trade VRE and other renewable electricity superiorly on the same spot markets and balancing systems as large central power plants and industrial consumers. The report asserts that VPP traders can earn profits through means of innovative trading strategies that exploit predictable market impacts caused by VRE power through a robust understanding of the electricity market and their unique access to data.
Denna rapport undersöker effekterna av variabel förnybar energi (VRE) på krafthandeln på den europeiska elhandelsmarknaden för stora aktörer. Den komplicerade driften av ett typiskt kraftutbyte i Europa åtföljs av ett lika komplicerat balanseringssystem. Den ökande mängden VRE i kraftsystemet, såsom vind- och solkraft, har långtgående effekter för krafthandlare på både denna elmarknad och motsvarande balanseringssystem. Som ett resultat utvecklas elmarknaden på enastående sätt och nya deltagare kommer in på spelplanen för att dra nytta av den förändrade dynamiken som orsakas av VRE-generatorer. En ny spelare, det virtuella kraftverket (VPP), har en fördel jämfört med andra marknadsaktörer genom att samla VRE-generatorer med styrbara förnybara energiproducenter, som biogas och vattenkraftverk, till en enhet. Detta gör att VPP både kan få tillgång till live VRE-produktionsdata som större anläggningar inte har, som den sedan använder för att distribuera olika underpooler av tillgångar och för att tillhandahålla balanstjänster till nätet. Därefter kan VPP: er handla med VRE och annan förnybar el på ett överlägset sätt på samma spotmarknader och balanseringssystem som stora centrala kraftverk och industrikonsumenter. Rapporten visar att VPP-handlare kan göra vinster genom innovativa handelsstrategier som utnyttjar förutsägbara marknadseffekter orsakade av VRE-kraft genom en detaljerad förståelse för elmarknaden och unik tillgång till data för produktionen av förnybar energi

QC 20201118

APA, Harvard, Vancouver, ISO, and other styles
46

Dhununjoy, Rakesh Kumar. "Meeting the Challenges for Increasing the Share of Variable Renewable Energy in the Generation Mix of Mauritius." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-150579.

Full text
Abstract:
As a Small Island Developing State (SIDS), Mauritius is exceptionally vulnerable. It faces similar threats to its survival as other SIDS, which include, inter alia, a strong reliance on a depleting natural resource base, loss of biodiversity and degradation of essential components of the ecosystem, and a heavy dependency on fossil fuels and other imported commodities that support society. Climate change, long distances that separating Mauritius from Africa and Asia, coupled with rising fuel costs exacerbates the situation considerably. Unless substantial and effective interventions are put in place soonest, the current and future generations may not be able to meet their needs. Being aware of the susceptibility of the island towards energy security, the Government of Mauritius is focused on diversifying the country’s energy supply, improving energy efficiency, addressing environmental and climate changes and modernizing our energy infrastructure in order to meet the challenges ahead. Besides security of supply and affordability the Government is attempting a rapid shift to a low carbon, efficient and environmentally benign energy system. This policy is integrated in a Long-Term Energy Strategy (LTES) that aims at reducing the dependency on fossil fuels and promoting energy generation from local renewable sources. However, increasing the current share of renewable energy from 20% to 35% by 2025 as  provided in the LTES, implies major investment in both RE technologies and at the same time in research studies in view to mitigate the upcoming challenges with increasing renewable generations in particular caused by VRE sources such as wind and solar. The aim of this thesis is therefore to identify the major problems and complexities arising with increasing share of VRE more specifically related to grid stability, security operation and power quality. The various problems related to unconscious continuous addition of VRE were identified and solutions were proposed on how to mitigate them in order to be able to reach the RE targets set out in the LTES.
APA, Harvard, Vancouver, ISO, and other styles
47

Frost, Ami Mariko Hood. "Disclosure of Abuse as a Moderating Variable for Internalized Shame in Adult Survivors of Childhood Sexual Abuse." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2101.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
48

Hülsing, Tobias [Verfasser]. "Probing quantum chromodynamics with the ATLAS detector : charged-particle event shape variables and the dijet cross-section / Tobias Hülsing." Mainz : Universitätsbibliothek Mainz, 2015. http://d-nb.info/1065687508/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
49

Weinzierl, Stefan. "QCD corrections to $e^+e^-\rightarrow 4$ jets." Phd thesis, Université Paris Sud - Paris XI, 1998. http://tel.archives-ouvertes.fr/tel-00000814.

Full text
Abstract:
Cette thèse a pour objet les corrections perturbatives de CDQ pour la production de quatre jets dans l'annihilation des électrons et positrons. Les corrections à une boucle pour le sous-processus $e^+ e^- \rightarrow q \bar{q} Q \bar{Q}$ sont calculées avec de nouvelles méthodes qui comprennent la décomposition de couleur, la méthode des spineur d'hélicité, et une décomposition inspirée par la supersymmétrie. Nous avons également profité des contraintes découlants de l'unitarité et des limites colinéaires pour restreindre la forme analytique des amplitudes. Dans une deuxième phase, j'ai écrit un programme numérique qui combine des contributions dues aux corrections radiatives des sous-processus $e^+ e^- \rightarrow q \bar{q} Q \bar{Q}$ et $e^+ e^- \rightarrow q g g \bar{q}$ et dues aux corrections d'émission réelle. Le programme utilise le formalisme des dipoles pour annuler les divergences infra-rouge. L'analyse numérique contient des résultats sur la section efficace totale, le paramètre $D$ et la variable d'élargissement d'un jet.
APA, Harvard, Vancouver, ISO, and other styles
50

Steidel, Katja. "Untersuchung der Auflösungsgrenzen eines Variablen Formstrahlelektronenschreibers mit Hilfe chemisch verstärkter und nicht verstärkter Negativlacke." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-66659.

Full text
Abstract:
Ziele wie eine hohe Auflösung und ein hoher Durchsatz sind bisher in der Elektronenstrahllithografie nicht gleichzeitig erreichbar; es existieren daher die Belichtungskonzepte Gaussian-Beam und Variable-Shaped-Beam (VSB), die auf Hochauflösung respektive Durchsatz optimiert sind. In dieser Arbeit wird der experimentelle Kreuzvergleich beider Belichtungskonzepte mit Hilfe chemisch verstärkter und nicht verstärkter Lacksysteme präsentiert. Als quantitativer Parameter wurde die Gesamtunschärfe eingeführt, die sich durch quadratische Addition der auflösungslimitierenden Fehlerquellen, also Coulomb-Wechselwirkungen (Strahlunschärfe), Lackprozess (Prozessunschärfe) und Proximity-Effekt (Streuunschärfe), ergibt. Für den Vergleich wurden wohldefinierte Prozesse auf 300 mm Wafern entwickelt und umfassend charakterisiert. Weitere Grundlage ist die Anpassung oder Neuentwicklung spezieller Methoden wie Kontrast- und Basedosebestimmung, Doughnut-Test, Isofokal-Dosis-Methode für Linienbreiten und Linienrauheit sowie die Bestimmung der Gesamtunschärfe unter Variation des Fokus. Es wird demonstriert, dass sich mit einer kleineren Gesamtunschärfe die Auflösung dichter Linien verbessert. Der direkte Vergleich der Gesamtunschärfen beider Belichtungskonzepte wird durch die variable Strahlunschärfe bei VSB-Schreibern erschwert. Da für die Bestimmung der Gesamtunschärfe keine Hochauflösung nötig ist, wird das Testpattern mit größeren Shots belichtet und induziert somit eine größere Gesamtunschärfe. Es wird gezeigt, dass die Prozessunschärfe den größten Anteil der Gesamtunschärfe stellt. Außerdem spielt die Streuunschärfe bei Lackdicken kleiner 100 nm und Beschleunigungsspannungen von 50 kV oder größer keine Rolle
Up to now, targets like high resolution and high throughput can not be achieved at the same time in electron beam lithography; therefore, the exposure concepts Gaussian-Beam and Variable-Shaped-Beam (VSB) exist, which are optimized for high resolution and throughput, respectively. In this work, the experimental cross-comparison of both exposure concepts is presented using chemically amplified and non-chemically amplified resist systems. For quantification the total blur parameter has been introduced, which is the result of the quadratic addition of the resolution limiting error sources, like Coulomb interactions (beam blur), resist process (process blur) and proximity-effect (scatter blur). For the comparison, well-defined processes have been developed on 300 mm wafers and were fully characterized. Further basis is the adaption or the new development of special methods like the determination of contrast and basedose, the doughnut-test, the isofocal-dose-method for line widths and line roughness as well as the determination of the total blur with variation of the focus. It is demonstrated, that the resolution of dense lines is improved with a smaller total blur. The direct comparison of the total blur values of both exposure concepts is complicated by the variable beam blur of VSB writers. Since high resolution is not needed for the determination of the total blur, the test pattern is exposed with larger shots on the VSB writer, which induces a larger total blur. It is shown that the process blur makes the largest fraction of the total blur. The scatter blur is irrelevant using resist thicknesses smaller than 100 nm and acceleration voltages of 50 kV or larger
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography