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Filion, Yves R. "Extended dynamic network modelling". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58667.pdf.
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Blanco, Blas. "Railway track dynamic modelling". Licentiate thesis, KTH, Farkost och flyg, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207180.
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The railway vehicles are an increasing mean of transportation due to, its reduced impact on environment and high level of comfort provided. These reasons have contributed to settle a positive perception of railway traffic into the European society. In this upward context, the railway industrial sector tackles some important challenges; maintaining low operational costs and controlling the nuisance by-products of trains operation, the most important being railway noise. Track dynamic plays a main role for both issues, since a significant part of the operational costs are associated with the track maintenance tasks and, the noise generated by the track can be dominant in many operational situations. This explains why prediction tools are highly valued by railway companies. The work presented in this licentiate thesis proposes methodologies for accurate and efficient modelling of railway track dynamics. Two core axes have led the development of this task, on one hand, the rail modelling and, on the other hand, the characterisation of the finite length nature of track supports. Firstly, concerning the rail modelling technique, it has evolved under two major premises. On one hand, regarding the frequency domain, it should describe high frequency behaviour of the rail. In order to accomplish with this first premise, a model based on Timoshenko beam theory is used, which can accurately account for the vertical rail behaviour up to 2500 Hz. On the other hand, with respect to the time domain, the response should be smooth and free of discontinuities. This last condition is fulfilled by implementation of the Timoshenko local deformation. Secondly, a model of support that considers its finite length nature is sought. For this purpose, a Timoshenko element over elastic foundation is formulated. Thus, the common model of support, which is based on a concentrated connection, is substituted by a distributed model of support. In this way, several enhancements are achieved; the temporal contact force response is smoothed and a more realistic shape is obtained, the amplitude of the displacement due to the parametric excitation is reduced and the magnitude associated to the ‘pin-pin’ frequency is not overestimated.QC 20170522
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Chen, C. C. "Imaging the spatial-temporal neuronal dynamics using dynamic causal modelling". Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18517/.
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Oscillatory brain activity is a ubiquitous feature of neuronal dynamics and the synchronous discharge of neurons is believed to facilitate integration both within functionally segregated brain areas and between areas engaged by the same task. There is growing interest in investigating the neural oscillatory networks in vivo. The aims of this thesis are to (1) develop an advanced method, Dynamic Causal Modelling for Induced Responses (DCM for IR), for modelling the brain network functions and (2) apply it to exploit the nonlinear coupling in the motor system during hand grips and the functional asymmetries during face perception. DCM for IR models the time-varying power over a range of frequencies of coupled electromagnetic sources. The model parameters encode coupling strength among areas and allows the differentiations between linear (within frequency) and nonlinear (between-frequency) coupling. I applied DCM for IR to show that, during hand grips, the nonlinear interactions among neuronal sources in motor system are essential while intrinsic coupling (within source) is very likely to be linear. Furthermore, the normal aging process alters both the network architecture and the frequency contents in the motor network. I then use the bilinear form of DCM for IR to model the experimental manipulations as the modulatory effects. I use MEG data to demonstrate functional asymmetries between forward and backward connections during face perception: Specifically, high (gamma) frequencies in higher cortical areas suppressed low (alpha) frequencies in lower areas. This finding provides direct evidence for functional asymmetries that is consistent with anatomical and physiological evidence from animal studies. Lastly, I generalize the bilinear form of DCM for IR to dissociate the induced responses from evoked ones in terms of their functional role. The backward modulatory effect is expressed as induced, but not evoked responses.
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Göl, Özdemir. "Dynamic modelling of induction machines /". Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phg595.pdf.
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Clements, Michael P. "Cointegration and dynamic econometric modelling". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334980.
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Qin, Yong. "Dynamic modelling of combustion processes". Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/55453/.
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Neural aided combustion oscillator models (NACO) have been developed for time domain prediction of low frequency oscillations. The NACO method consists of two stages, one is the design of a core-stimulation (CS) model based on the co.
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Somarathne, Shini. "Dynamic thermal modelling using CFD". Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/5523.
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Buildings expend vast quantities of energy, which has a detrimental impact on the environment. Buildings systems are often oversized to cope with possible extreme environmental conditions. Building simulation provides an opportunity to improve building thermal design, but the available tools are typically used in combination in order to overcome their individual deficiencies. Two such tools, often used in tandem are computational fluid dynamics (CFD) and dynamic thermal modelling (DTM). DTM provides a coarse analysis, by considering external and internal thermal conditions over a building (including its fabric) over time. CFD is usually used to provide steady state analysis. Boundary conditions typically in the form of surface temperatures are manually input from DTM into CFD. CFD can model buildings dynamically, but is not commonly used, since solving for hugely different time constants of solid and air pose significant limitations, due to data generated and time consumed. A technique is developed in this study to tackle these limitations. There are two main strands to the research. DTM techniques had to be incorporated into CFD, starting from first principles of modelling heat transfer through solid materials. These were developed into employing the use of functions such as the 'freeze flow' function (FEF) and the 'boundary freeze' function (BFF) in combination with a time-varying grid schedule to model solids and air simultaneously. The FFF pauses the solution of all governing equations of fluid flow, except temperature. The BFF can be applied to solid boundaries to lock their temperatures whilst all other equations are solved. After extensive research the established DTM-CFD Procedure eventually used the FEF and BFF with transient periods and steady state updates, respectively. The second strand of research involved the application of the DTM-CFD Procedure to a typical office space over a period of 24-hours. Through inter-model comparisons with a fully transient simulation, the DTM-CFD Procedure proved to be capable of providing dynamic thermal simulations 16.4% more efficiently than a typical CFD code and more accurately than a typical DTM code. Additional research is recommended for the further improvement of the DTM-CFD Procedure.
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Hinchliffe, Mark. "Dynamic modelling using genetic programming". Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391407.
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Crump, Timothy. "Modelling dynamic cracking of graphite". Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/modelling-dynamic-cracking-of-graphite(71e81d6f-e712-458c-aa48-0a256749258a).html.
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Advances in dynamic fracture modelling have become more frequent due to increases in computer speed, meaning that its application to industrial problems has become viable. From this, the author has reviewed current literature in terms of graphite material properties, structural dynamics, fracture mechanics and modelling methodologies to be able to address operational issues related to the ageing of Advanced Gas-cooled Reactor (AGR) cores. In particular, the experimentally observed Prompt Secondary Cracking (PSC) of graphite moderator bricks which has yet to be observed within operational reactors, with the objective of supporting their plant life extension. A method known as eXtended Finite Element Method with Cohesive Zones (XCZM) was developed within Code_Aster open-source FEM software. This enabled the incorporation of velocity toughening, irradiation-induced material degradation effects and multiple 3D dynamic crack initiations, propagations and arrests into a single model, which covers the major known attributes of the PSC mechanism. Whilst developing XCZM, several publications were produced. This started with first demonstrating XCZM's ability to model the PSC mechanism in 2D and consequently that methane holes have a noticeable effect on crack propagation speeds. Following on from this, XCZM was benchmarked in 2D against literature experiments and available model data which consequently highlighted that velocity toughening was an integral feature in producing energetically correct fracture speeds. Leading on from this, XCZM was taken into 3D and demonstrated that it produced experimentally observed bifurcation angle from a literature example. This meant that when a 3D graphite brick was modelled that the crack profile was equivalent to an accepted quasi-static profile. As a consequence of this validation, the XCZM approach was able to model PSC and give insight into features that could not be investigated previously including: finer-scale heterogeneous effects on a dynamic crack profile, comparison between Primary and Secondary crack profiles and also, 3D crack interaction with a methane hole, including insight into possible crack arrest. XCZM was shown to improve upon previous 2D models of experiments that showed the plausibility of PSC; this was achieved by eliminating the need for user intervention and also incorporation of irradiation damage effects through User-defined Material properties (UMAT). Finally, while applying XCZM to a full-scale 3D graphite brick including reactor effects, it was shown that PSC is likely to occur under LEFM assumptions and that the Secondary crack initiates before the Primary crack arrests axially meaning that modal analysis would not be able to fully model PSC.
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Alfaer, Nada Mansour. "Dynamic modelling for image analysis". Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/21215/.
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Image segmentation is an important task in many image analysis applications, where it is an essential first stage before further analysis is possible. The levelset method is an implicit approach to image segmentation problems. The main advantages are that it can handle an unknown number of regions and can deal with complicated topological changes in a simple and natural way. The research presented in this thesis is motivated by the need to develop statistical methodologies for modelling image data through level sets. The fundamental idea is to combine the level-set method with statistical modelling based on the Bayesian framework to produce an attractive approach for tackling a wider range of segmentation problems in image analysis. A complete framework for a Bayesian level set model is given to allow a wider interpretation of model components. The proposed model is described based on a Gaussian likelihood and exponential prior distributions on object area and boundary length, and an investigation of uncertainty and a sensitivity analysis are carried out. The model is then generalized using a more robust noise model and more flexible prior distributions. A new Bayesian modelling approach to object identification is introduced. The proposed model is based on the level set method which assumes the implicit representation of the object outlines as a zero level set contour of a higher dimensional function. The Markov chain Monte Carlo (MCMC) algorithm is used to estimate the model parameters, by generating approximate samples from the posterior distribution. The proposed method is applied to simulated and real datasets. A new temporal model is proposed in a Bayesian framework for level-set based image sequence segmentation. MCMC methods are used to explore the model and to obtain information about solution behaviour. The proposed method is applied to simulated image sequences.
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Denesuk, Matthew 1965. "Modelling of dynamic wetting phenomena". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/291345.
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A general dynamic wetting model is presented in which surface and gravitational driving energies are balanced against energy lost through bulk viscous dissipation. Behavior is described in terms only of independently measurable quantities, with no adjustable parameters. Additionally, the model can be expressed so as to predict liquid viscosity as a function of dynamic wetting behavior. Application of the model to a lead-silicate liquid on a gold substrate demonstrate excellent agreement of the model with experiment. The general framework of the model is especially amenable to the incorporation of other physico-chemical processes which may impact dynamic wetting phenomena. Examples are given which extend the model to specific cases where substrate roughness and/or substrate dissolution are important. Additionally, the dynamic wetting model is extended to porous substrates, accounting for the effects of composite interface formation and depletion of the liquid via capillary flow.
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Periorellis, Panayiotis. "Dynamic enterprise modelling : a methodology for animating dynamic social networks". Thesis, University of Newcastle Upon Tyne, 2000. http://hdl.handle.net/10443/2134.
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Since the introduction of the Internet and the realisation of its potential companies have either transformed their operation or are in the process of doing so. It has been observed, that developments in I.T., telecommunications and the Internet have boosted the number of enterprises engaging into e-commerce, e-business and virtual enterprising. These trends are accompanied by re-shaping, transformation and changes in an enterprise's boundaries. The thesis gives an account of the research into the area of dynamic enterprise modelling and provides a modelling methodology that allows different roles and business models to be tested and evaluated without the risk associated with committing to a change.
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Kilic, Boran. "Dynamic Modelling Of A Backhoe-loader". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611002/index.pdf.
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The aim of this study is to develop a dynamic model of the loader system of a backhoe-loader. Rigid bodies and joints in the loader mechanism and loader hydraulic system components are modelled and analyzed in the same environment using the physical modelling toolboxes inside the commercially available simulation software, MATLAB/Simulink. Interaction between the bodies and response of the hydraulic system are obtained by co-operating the mechanical and hydraulic analyses. System variables such as pressure, flow and displacement are measured on a physical machine and then compared with the simulation results. Simulation results are consistent with the measurement results. The main result of this work is the ability to determine the dynamic loads on the joints and attachments of the backhoe-loader. In addition to that, prototyping time and costs can be highly reduced by implementing this model in the design process.
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Bowsher, Clive G. "Papers in multivariate dynamic econometric modelling". Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413018.
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Geitner, Gert-Helge, i Guven Komurgoz. "Power Flow Modelling of Dynamic Systems". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-171305.
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As tools for dynamic system modelling both conventional methods such as transfer function or state space representation and modern power flow based methods are available. The latter methods do not depend on energy domain, are able to preserve physical system structures, visualize power conversion or coupling or split, identify power losses or storage, run on conventional software and emphasize the relevance of energy as basic principle of known physical domains. Nevertheless common control structures as well as analysis and design tools may still be applied. Furthermore the generalization of power flow methods as pseudo-power flow provides with a universal tool for any dynamic modelling. The phenomenon of power flow constitutes an up to date education methodology. Thus the paper summarizes fundamentals of selected power flow oriented modelling methods, presents a Bond Graph block library for teaching power oriented modelling as compact menu-driven freeware, introduces selected examples and discusses special features.
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Sturacci, Jean. "MODELLING OF MACHINING SYSTEMS DYNAMIC BEHAVIOUR". Thesis, KTH, Industriell produktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174021.
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The understanding of the static and dynamic behaviour of machine tools and the cutting processes interaction is of the main importance when designing a machining system. Moreover, the endless increase demand on quality and productivity gives even more prominence to that. Actually in machining, a central problem is the one of the stability of the cutting process. The choice of the optimal parameters of cut is a challenge that researchers and companies are facing with different approaches. The traditional method to determine these parameters consists of determining the Stability Lobe Diagram through modal analysis and cutting tests. However, in many applications, this method does not give accurate results. To face that, this thesis presents a computational model, integrated in SimMechanics (Matlab / MathWorks), of a whole machining system to analyse its behaviour and study its stability depending on the cutting parameters and machine tool configuration. The model implementation is shown in this thesis and the results obtained are analysed and evaluated.
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Sicilia, Garcia E. I. "A study in dynamic language modelling". Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395213.
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Njabeleke, Ignatius Andem. "Mathematical modelling of nonlinear dynamic systems". Thesis, University of Westminster, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319624.
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Al-Turki, Y. A. "Dynamic modelling of a large turboalternator". Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374533.
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Netherton, Lee. "Dynamic modelling of the SABRE engine". Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440983.
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Argyros, Alexandros. "Efficient dynamic modelling of deepwater moorings". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610791.
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Kaislaniemi, Lars Mikael. "Dynamic modelling of post-collisional magmatism". Thesis, Durham University, 2015. http://etheses.dur.ac.uk/10970/.
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This study addresses the question of post-collisional magmatism and its production mechanisms, addressing especially the mantle processes involved. Numerical experiments are conducted to examine the effects of viscosity weakening by subduction related water content increase in the upper mantle and the resulting sub-lithospheric small-scale convection. The models presented incorporate parameterized and thermodynamic melting models, and take into account variable relationships between mantle water content, mantle strength, water extraction by partial melting and related depletion stiffening. The results demonstrate the possible importance of so called ”hydrous activation” of the lithosphere-asthenosphere boundary: The post-collisional loss of the lithospheric mantle can be initiated and augmented by the elevated upper mantle water contents that enhances the sub-lithospheric small-scale convection, increases heat flow into the lithosphere, and produces localized lithosphere thin- ning. The irregular spatial and temporal melting patterns and the mantle melt volumes correspond to typical post-collisional mantle-derived magmatism. The small-scale convection can be localized into an edge-driven convection by significant lithosphere thickness gradients, e.g. craton edges. This helps to understand the uplift and volcanism observed in intraplate orogenic settings and implies the importance of these processes at other locations of lithosphere thickness gradients, e.g. recent collision zones. The lithospheric thinning produced by small-scale convection can initiate whole lithosphere mantle loss via positive feedback mechanisms: gradual thinning of the lithosphere causes partial melting in the lowermost crust, weakening the crust-mantle boundary and providing a detachment mechanism for the lithospheric mantle, leading to stronger lithosphere thinning and, finally, exposure of the lower crust to the hot asthenosphere. Small-scale convection and processes related to or initiated by it offer new insight and future research possibilities in studies of continental collision magmatism.
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Searle, Graham Ellis. "Dynamic modelling of electronic nose systems". Thesis, University of Warwick, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251118.
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Bons, Daniel. "Modelling peripheral vision in dynamic situations". Thesis, Linköpings universitet, Institutionen för medicinsk teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158641.
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Metamers of the ventral stream is a model which tries to describe what information we gather from our visual field. It have previously only been tested on static images. This thesis have continued the research and applied it to dynamic images in order to investigate if the model can be seen as a functional representation of our visual field. The results show that the model, at this stage, can not be seen as a fully functional representation of the visual field, but it can be used to determine the detectability of objects in the periphery. It also shows that what we humans perceive as motion is, at least to some extent, merely a change of the statistics in our visual field.
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Aliye, Kuerban <1988>. "Dynamic modelling trophic networks with BioPEPA". Master's Degree Thesis, Università Ca' Foscari Venezia, 2016. http://hdl.handle.net/10579/8140.
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We consider a process algebra for modelling and the analysis of biochemical network, called Bio-PEPA. It is based on PEPA, a process algebra originally defined for the performance analysis of computer systems, and extended in order to handle some features of biochemical networks, such as stoichiometry and different kinds of kinetic laws. In Bio-PEPA we can make different kinds of analysis, static and dynamic. In this thesis we focus on the dynamic analysis of trophic networks. A trophic network represents an ecological community of organisms and their feeding relations. We will first consider a toy case of trophic network described in a Bio-PEPA model, and then we apply the same ideas to a real case of trophic network, namely the Venice Lagoon.
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Epiphaniou, Nicholas. "Modelling of Dynamic Friction Across Solid Material Interfaces Using Molecular Dynamics Techniques". Thesis, Cranfield University, 2009. http://hdl.handle.net/1826/4458.
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The topic of this PhD is to investigate materials interfaces under the application of com-pressive forces and dynamic friction. Friction studies are important in applications for high-speed machining and ballistic penetration modelling, two areas where it is important to understand the behaviour of rapidly moving interfaces. Gaining insight into the velocity dependence of the effective tangential force, and its time-evolution, under various external loads is also of particular interest. It is important to understand on an atomic and/or molec-ular level the fundamentals of tribological processes. Some of the processes investigated in this thesis include plastic deformation due to high compression, the response of materials when sliding occurs in terms of temperature variation across the interface and its relation-ship with atomic diffusion. Moreover, the materials dependence on operating conditions of temperature, loading and dynamic friction are factors that ultimately determine the design of tribological systems.
In the last few years it has been shown that materials properties depend on the size, as smaller specimens are relatively stronger than larger ones. This thesis is aiming to em-ploy state of the art numerical and theoretical methods, which are vital to give a significant insight and understanding of the fundamental issues concerning dynamic friction of tribo-logical processes at the atomic scale. The mechanical behaviour is investigated in detail to reveal an accurate theoretical description of the frictional force at metallic surfaces. Special consideration is taken into account for the mechanism that causes dissipation in the form of heat. The strong deformation when materials undergo dynamic friction causes energy to dissipate away from the interface at a high rate.
Additionally, investigation of the plastic deformation and its variation under conditions prevalent at high speed sliding is carried out. Knowledge of the yield point under these conditions is important to obtain accurate constitutive models for the shear stresses. In-vestigating how the material strength varies under sliding friction and obtaining accurate evaluation of the stresses involved has proved difficult and time consuming. This is primar¬ily attributed to the fact that experiments are difficult to conduct and expensive facilities are required. This thesis focuses on aspects of this complex process with the aid of molecular dynamic simulations.
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Faller, Daniel. "Analysis and dynamic modelling of complex systems". [S.l. : s.n.], 2003. http://www.freidok.uni-freiburg.de/volltexte/777.
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Breyer, Laurent [Verfasser]. "Dynamic Modelling of Ground Antennas / Laurent Breyer". Aachen : Shaker, 2012. http://d-nb.info/1069045209/34.
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Uzir, Mohamad Hekarl. "Dynamic modelling and simulation of biocatalytic reactions". Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1446784/.
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Enzyme catalysis is of key importance in the synthesis of new fine chemicals. The use of enzymes to undertake chemical conversion has become commonplace among pharmaceutical companies alongside conventional catalysis. This is mainly due to the working conditions of enzyme-catalysed reactions, the specificity as well as stereo- and regio- selectivity of enzymes as biocatalysts. Many novel techniques have been developed to carry out such catalysis ranging from a simple batch reactor to a complex fiuidised bed reactor. Evaluating these techniques requires experimental work and repeat experiments and through these, optimised conditions could be achieved for better yield and productivity. Experimental work is costly and the only cost-effective method is to introduce computer-based experiments via mathematical modelling. For this purpose, a complete kinetic study based on mechanisms of general enzyme-catalysed reactions was established and the Michaelis-Menten type kinetics has been used as the basis of the steady-state analysis. Prior to the steady-state kinetics, dynamic analyses of enzyme-catalysed reactions were also undertaken and this has led to the understanding of the quasi steady-state assumption that governed the model. New conditions were proposed for the validity of this assumption and the stability of enzyme-catalysed reactions. In this work, Baeyer-Villiger monooxygenase enzyme-catalysed synthesis of optically pure lactone was used as a model system. A complete model of the rate expression of Baeyer-Villiger reaction was devised. This provided the foundation of the fed-batch whole cell process model carried out as the main part of this work. The effect of substrate and product inhibitions was integrated into this model system and an outcome comparable to that of the experimental data was achieved. The whole cell process system has been found to be affected by membrane diffusivity during the course of reaction. This has led to the introduction of diffusion coefficients for both substrate and product into the process model. A simple enzyme-catalysed reaction-diffusion system was successfully modelled and numerically solved. Finally, stability analysis was carried out in order to prove and understand the particular biocatalytic process system.
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Fouché, Casper Hendrik. "Dynamic modelling of banking activities / C.H. Fouché". Thesis, North-West University, 2007. http://hdl.handle.net/10394/2029.
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Avraam, Marios. "Modelling and optimisation of hybrid dynamic processes". Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321942.
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Kaparis, Stathis. "Dynamic conditional correlation modelling for asset returns". Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536010.
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Sainoki, Atsushi. "Dynamic modelling of mining-induced fault-slip". Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123291.
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In deep hard rock mines where high stress conditions take place, rockbursts are serious problems because rockbursts could result in severe damage to mine openings. It is widely recognized that mining activities could reactivate faults in underground mines. The reactivation of faults could then cause fault-slip. More importantly, fault-slip gives rise to seismic waves, which inflict severe damage to mine openings. Because the generation and propagation of seismic waves are dynamic phenomena, fault-slip needs to be also dealt with as a dynamic phenomenon. Both of the static and dynamic behaviour of faults should be examined, considering the effects of mining activities on the faults, in order to estimate the damage induced by the seismic waves First, a literature review is conducted. The review has revealed that although a number of dynamic and static friction laws have been proposed, the friction laws have been rarely employed for the simulation of fault-slip in underground mines. The review has also revealed that most of the simulations have been conducted in static conditions. In this thesis, dynamic modelling of mining-induced fault-slip is presented using a mine-wide model encompassing a fault. Furthermore, a case study of Garson Mine, Sudbury, Canada is carried out. A parametrical study with a mine-wide 3D model has led to the following conclusions: (a) mining depth, friction angle of the fault, and fault locations exert a large influence on the maximum relative shear displacements on the fault, while the dilation angle and stiffness of the fault do not, (b) maximum slip rates appear to increase with the maximum slip. Results obtained from the numerical analysis employing Barton's shear strength model have shown that fault surface roughness strongly affects the intensity of seismic waves and seismically radiated energy. The results imply that fault-slip occurring on faults with rough surfaces could become more violent. The effect of stope production blasts on a nearby fault is also examined. The results obtained from the analysis have indicated that performing stope production blasts in timed sequence could induce a larger seismic event on the fault than triggering the blasts simultaneously. Dynamic analysis considering the collision and unloading of fault surface asperities is also conducted. It is found that the release of normal stress due to fault unloading has a large influence on the intensity of seismic waves. The effect of slip-weakening distance on seismic source parameters of fault-slip is also investigated. The study has indicated that slip rates and seismically radiated energy are significantly affected by the slip-weakening distance, while seismic moment appears not to be susceptible to the slip-weakening distance in a case of local fault-slip.Back analysis of fault-slip to estimate the physical and mechanical properties of shear/fracture zones is carried out for Garson Mine. The back analysis is conducted with respect to moment magnitude and peak particle velocities recorded by seismic monitoring systems. Fault surface roughness and a dynamic friction angle have been calibrated. Afterwards, the calibrated values are validated with peak ground acceleration. Through the study, a methodology to calibrate the physical and mechanical properties of faults by means of ground motion due to seismic waves arising from fault-slip as well as seismic source parameters of the fault-slip has been developed.Dans les mines profondes ou des contraintes élevées se produisent, les coups de terrain sont un problème car les ils peuvent endommager les ouvertures minières. Il est largement reconnu que les activités minières peuvent réactiver des failles dans les mines sous-terraines. La réactivation de ces failles peut entrainer un glissement de faille. Surtout, le glissement de faille fait naitre des ondes sismiques qui infligent des dégâts sérieux quand elles frappent la surface des ouvertures minières. La génération et la propagation des ondes sismiques sont des phénomènes dynamiques. Il s'ensuit donc que le glissement de faille doit être traité comme un phénomène dynamique Le comportement dynamique ainsi que le comportement statique des failles doit être examiné en considérant les effets des activités minières pour estimer les dégâts causés par les ondes sismiques.Premièrement, un examen de la documentation est effectué. L'examen a révélé que même si un nombre de lois statiques et dynamiques de frottement ont été proposés, ces lois de frottement ont été peu employés pour simuler les glissements de faille que se déroulent dans les mines sous-terraines. La revue a aussi révélé que la majorité des simulations ont été conduites en conditions statiques. Dans cette thèse, la modélisation dynamique d'un glissement de faille induit par des activités minières est présentée. Le modèle englobe l'entièreté d'une mine. En plus, une étude de cas pour la mine Garson à Sudbury, au Canada, est effectuée.Une étude paramétrique avec un modèle de mine en trois dimensions mène aux conclusions suivantes: (a) la profondeur d'exploitation minière, l'angle de friction de la faille, et la position de la faille ont une grande influence sur les déplacement relatifs en cisaillement d'une faille, tandis que l'angle de dilation de la faille et la dureté ont peu d'effet, (b) le taux de glissement maximal augmente en fonction du glissement absolu. Les résultats obtenus du modèle numérique dans lequel le modèle de résistance au cisaillement de Barton est implémenté ont démontré que la rugosité de la surface de la faille affecte grandement l'intensité des ondes sismiques qui émanent du glissement de faille et l'énergie sismique propagée. Les résultats impliquent qu'un glissement de faille survenant à une faille rugueuse est plus violent. L'effet produit par un sautage de production sur une faille proche est aussi examiné en considérant plusieurs séquences de sautage. Les résultats de l'analyse indiquent qu'un sautage de production exécuté selon une séquence temporelle peut induire un plus grand événement sismique qu'un sautage simultané. Une analyse dynamique tenant compte la collision et le déchargement d'une faille est aussi conduite. Il est démontré que le relâchement de la contrainte normale à la faille a une grande influence sur l'intensité des ondes sismiques. L'effet de la distance d'affaiblissement de faille due glissement sur les paramètres sismiques est aussi examiné L'étude indique que le taux de glissement et l'énergie sismique émanée sont significativement affectés par la distance d'affaiblissement de faille, tandis que le moment sismique n'est pas susceptible à la distance d'affaiblissement dans le cas ou le glissement de faille se déroule seulement dans une zone limitée. Pour estimer l'effet des propriétés physiques et mécaniques de la zone de cisaillement, une analyse régressive est exécutée pour la mine Garson. L'analyse est conduite selon la magnitude du moment et la vitesse de crête des particules. La rugosité de la surface de la faille et l'angle de friction dynamique sont étalonnés. Ensuite, les paramètres étalonnés sont validés par rapport à l'accélération maximale du terrain. À travers l'étude, une méthodologie pour étalonner les propriétés physiques et mécaniques de la faille selon l'étude du mouvement du terrain due aux ondes sismiques émanant d'un glissement de faille est développé.
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Alkindi, Ahmed Bin Masoud Bin Ali. "Performance optimisation through modelling and dynamic prediction". Thesis, University of Warwick, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399475.
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Abdel-Razik, Mohamed Hassan. "Dynamic modelling of facultative waste stabilization ponds". Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46634.
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Parvizi, Mansour. "Centrifuge modelling of low energy dynamic compaction". Thesis, University of Manchester, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495952.
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Low Energy Dynamic Compaction (LEDC) is a recently adopted approach for the rapid improvement of the mechanical behaviour of soil to a relatively shallow depth over a limited area. This method of compaction is termed `low energy' because the energy input per blow is low compared with that imparted by traditional dynamic compaction techniques. The field apparatus for this method was designed originally by BSP/DRA for the rapid repair of bomb damaged airfield runways, but later adopted as a method of ground improvement. This thesis describes the design and operation of a unique model compactor simulating the action of a low energy compactor in the centrifuge. The centrifuge study has been undertaken at 20g using a tamper mass of 0.875 kg falling through 100mm onto a stiff aluminium target, having a mass 0.268 kg and a diameter of 100mm. This simulated a field scale tamper mass of approximately seven tonnes falling through two meters onto a target having a base area of 3.14m2. This research required the development, for use in the centrifuge, of a process monitoring system proposed by Allen (1996), where the improvement in the ground characteristics may be evaluated with the execution of the improvement process. The procedure was based on the principles of the WAK test ( Briaud and Lepert, 1990 ) which was devised to provide, by means of a very simple test, an estimate of the static stiffness of a soil/footing system, thus removing the necessity for expensive pre- and post- test investigations. The monitoring system required the innovative deployment of miniature instrumentation on the pounder and the target to measure both input force and output accelerations In order to analyse the soil response to the impact it is necessary to obtain both the signature of the energy input and soil response in terms of acceleration and transient earth pressures for each impact. This was achieved by the use of a dynamic load cell mounted on the drop weight, an accelerometer on the target and accelerometers and dynamic earth pressure cells embedded within the soil mass.
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MacNish, Craig Gordon. "Nonmonotonic inference systems for modelling dynamic processes". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240195.
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Hodge, Steven James. "Dynamic interface modelling and simulation fidelity criteria". Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540061.
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Ratcliffe, Colin Paul. "Dynamic structural modelling for time domain analysis". Thesis, University of Southampton, 1985. https://eprints.soton.ac.uk/52303/.
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Mealing, Richard Andrew. "Dynamic opponent modelling in two-player games". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/dynamic-opponent-modelling-in-twoplayer-games(def6e187-156e-4bc9-9c56-9a896b9f2a42).html.
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This thesis investigates decision-making in two-player imperfect information games against opponents whose actions can affect our rewards, and whose strategies may be based on memories of interaction, or may be changing, or both. The focus is on modelling these dynamic opponents, and using the models to learn high-reward strategies. The main contributions of this work are: 1. An approach to learn high-reward strategies in small simultaneous-move games against these opponents. This is done by using a model of the opponent learnt from sequence prediction, with (possibly discounted) rewards learnt from reinforcement learning, to lookahead using explicit tree search. Empirical results show that this gains higher average rewards per game than state-of-the-art reinforcement learning agents in three simultaneous-move games. They also show that several sequence prediction methods model these opponents effectively, supporting the idea of using them from areas such as data compression and string matching; 2. An online expectation-maximisation algorithm that infers an agent's hidden information based on its behaviour in imperfect information games; 3. An approach to learn high-reward strategies in medium-size sequential-move poker games against these opponents. This is done by using a model of the opponent learnt from sequence prediction, which needs its hidden information (inferred by the online expectation-maximisation algorithm), to train a state-of-the-art no-regret learning algorithm by simulating games between the algorithm and the model. Empirical results show that this improves the no-regret learning algorithm's rewards when playing against popular and state-of-the-art algorithms in two simplified poker games; 4. Demonstrating that several change detection methods can effectively model changing categorical distributions with experimental results comparing their accuracies to empirical distributions. These results also show that their models can be used to outperform state-of-the-art reinforcement learning agents in two simultaneous-move games. This supports the idea of modelling changing opponent strategies with change detection methods; 5. Experimental results for the self-play convergence to mixed strategy Nash equilibria of the empirical distributions of plays of sequence prediction and change detection methods. The results show that they converge faster, and in more cases for change detection, than fictitious play.
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Guimarães, João Henrique Diniz. "Modelling the dynamic interactions of rolling bearings". Berlin Logos-Verl, 2007. http://d-nb.info/990541959/04.
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Guimarães, João Henrique Diniz. "Modelling the dynamic interactions of rolling bearings /". Berlin : Logos, 2008. http://deposit.d-nb.de/cgi-bin/dokserv?id=3160007&prov=M&dok%5Fvar=1&dok%5Fext=htm.
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Van, Aswegen Karl. "Dynamic modelling of a stented aortic valve". Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1747.
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Li, Ying. "Modelling and optimisation of dynamic motorway traffic". Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1474219/.
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Ramp metering, variable speed limits, and hard shoulder running control strategies have been used for managing motorway traffic congestion. This thesis presents a modelling and optimisation framework for all these control strategies. The optimal control problems that aim to minimise the travel delay on motorways are formulated based upon a macroscopic cell transmission model with piecewise linear fundamental diagram. With the piecewise linear nature of the traffic model, the optimal control problems are formulated as linear programming (LP) and are solved by the IBM CPLEX solver. The performance of different control strategies are tested on real scenarios on the M25 Motorway in England, where improvements were observed with proper implementation. With considering of the uncertainties in traffic demand and characteristics, this thesis also presents a robust modelling and optimisation framework for dynamic motorway traffic. The proposed robust optimisation aims to minimise both mean and variance of travel delays under a range of uncertain scenarios. The robust optimisation is formulated as a minimax problem and solved by a two stage solution procedure. The performances of the robust ramp metering are illustrated through working examples with traffic data collected from the M25 Motorway. Experiments reveal that the deterministic optimal control would outperform slightly the robust control in terms of minimising average delays, while the robust controller gives a more reliable performance when uncertainty is taken into account. This thesis contributes to the development and validation of dynamic simulation, and deterministic and robust optimisation.
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KHAN, KHURRAM IMRAN. "Fluid dynamic modelling of bubble column reactors". Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2528494.
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Numerical simulations of rectangular shape bubble column reactors (BCR) are validated starting from preliminary simulations aimed at identifying proper simulation parameters for a given system and resulting up to the numerical simulation with mass transfer and chemical reactions. The transient, three dimensional simulations are carried out using FLUENT software and the results obtained for a system with low gas flow rate (48 L/h) indicated that we need enough fine mesh grid and appropriate closure of interfacial forces to predict reliably plume oscillation period, liquid axial velocity and gas holdup profiles. In case of high flow rate (260 L/h), we compared the results for the effect of different interfacial closure forces and change in inlet boundary condition for gas volume fraction. There is no change in hydrodynamic results when there is change in gas volume fraction at inlet boundary condition. The effect of virtual mass interfacial force on the simulation results is also negligible. However, the major effects of applying lift force on results of plume oscillation period, liquid axial velocity and gas holdup is predicted. For comparable simulation results to experimental data, it is suggested that requirement of enough fine grids and appropriate correlations for interfacial forces, especially the combination of drag and lift forces is necessary.
To study the bubble size distribution in BCR the numerical simulations are carried out with QMOM population balance technique for air-water fluid system. After finalization of the generic moment boundary conditions with simulations with PBM using QMOM without breakage and coalescence phenomena, then we simulated the system with breakage and coalescence and eventually, the simulation results are compared with experimental and simulation data taken from the scientific literature. For better hydrodynamics results of BCR as compared to experimental results, the interfacial lift force with combination of drag force is predicted for QMOM. The discretization scheme for gas volume fraction and moments of first order upwind provided the expected results of bubble size distribution. The simulation result of QMOM with breakage and coalescence models were also in good agreement with hydrodynamics experimental results and simulation results of class methods and DQMOM for bubble size distribution results.
The modelling of chemical absorption of pure CO2 gas in caustic solution is carried out in a rectangular BCR with identical simulation parameters settings of previous work. For applicability of available kinetic and physical data we developed concentration differential equations to estimate the species molar concentration with respect to time in MATLAB code. The obtained profiles of evaluation of concentration and pH were in similar fashion as compared to available CFD simulated concentration and pH profiles at a point in the bubble column with respect to time. CFD simulation taking into account the mass transfer and chemical reaction, the E-E approach is used with assumption of uniform bubble size for modelling of chemisorption of the CO2 gas bubbles into NaOH aqueous solution. The adopted models successfully predicted the hydrodynamics results and are in good agreement with experimental and simulation results, however, reaction processes results are not as per expectation and further improvement in adopted simulation methods is required for better results.
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Romanel, Alessandro. "Dynamic Biological Modelling: a language-based approach". Doctoral thesis, Università degli studi di Trento, 2010. https://hdl.handle.net/11572/368272.
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Systems biology investigates the interactions and relationships among the components of biological systems to understand how they globally work. The metaphor “cells as computations†, introduced by Regev and Shapiro, opened the realm of biological modelling to concurrent languages. Their peculiar characteristics led to the development of many different bio-inspired languages that allow to abstract and study specific aspects of biological systems. In this thesis we present a language based on the process calculi paradigm and specifically designed to account for the complexity of signalling networks. We explore a new design space for bio-inspired languages, with the aim to capture in an intuitive and simple way the fundamental mechanisms governing protein-protein interactions. We develop a formal framework for modelling, simulating and analysing biological systems. An implementation of the framework is provided to enable in-silico experimentation.
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Romanel, Alessandro. "Dynamic Biological Modelling: a language-based approach". Doctoral thesis, University of Trento, 2010. http://eprints-phd.biblio.unitn.it/282/1/PhD-Thesis.pdf.
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Systems biology investigates the interactions and relationships among the components of biological systems to understand how they globally work. The metaphor “cells as computations”, introduced by Regev and Shapiro, opened the realm of biological modelling to concurrent languages. Their peculiar characteristics led to the development of many different bio-inspired languages that allow to abstract and study specific aspects of biological systems. In this thesis we present a language based on the process calculi paradigm and specifically designed to account for the complexity of signalling networks. We explore a new design space for bio-inspired languages, with the aim to capture in an intuitive and simple way the fundamental mechanisms governing protein-protein interactions. We develop a formal framework for modelling, simulating and analysing biological systems. An implementation of the framework is provided to enable in-silico experimentation.
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Huang, Pengyu. "Multiscale Modelling of Dynamic Contact Angles for CO2-Water-Silica Systems". Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20937.
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The capillary and dynamic wetting behaviour in porous media is crucial in many engineering problems which are highly related to the multiphase interactions between fluids and solids. This thesis will focus on the behaviour of dynamic contact angle of the supercritical CO2/water flow in the silica slit as a function of the contact line velocity at both the nanoscale and microscale, which can help us gain an in-depth understanding of the dynamic processes in CO2 geosequestration in saline aquifers. Our molecular dynamics (MD) simulations calculate the contact angle quantitatively at different velocities at the nanoscale and also validate the molecular kinetic theory through the detailed analysis of the equilibrium jump distance and frequency of the water and CO2 molecules at the solid surfaces. While the MD simulations provide the results of dynamic contact angle at the nanoscale, which can be suitable for the nanopores of the low permeability rock, the dynamic contact angle behaviour at the microscale is also important and investigated in this thesis. This work also develops a coarse-grained molecular dynamic (CGMD) framework to model the liquid-vapour-solid interactions at the microscale. The newly developed CGMD framework has been applied and extended to the study of the dynamic contact angle for the CO2-water-silica system at the microscale. The microscale CGMD simulation of CO2-water-silica system shows that there is an increase in the CO2 contact angle as the increase of the contact line velocity at three different pressures. The dynamic contact angles under a water pressure of 18.9 MPa seem to be slightly larger than those under the water pressures of 9.41 MPa and 14.3 MPa. Moreover, the comparison between the MD and CGMD results suggests that there could be a pore size effect on the dynamic contact angle for the studied CO2-water-silica system.
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Richardson, Fiona Mary. "Dynamic representations in character production and recognition". Thesis, University of Hertfordshire, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289606.
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Catanas, Fernando Jorge de Lyz Girou Rodrigues. "Heuristics for the dynamic portfolio problem". Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322226.
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