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121 
Development of a mathematical Nline model for simulation of beach changesDang, Van To, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2006 (has links)
The development of a new NLine model, which provides a practical tool for simulating regional beach changes induced by short and longterm processes, is described in this thesis. The new NLine model consists of four main modules that together describe the hydrodynamic and morphological responses. The four constituent modules have been integrated based on a wide range of research including the utility and function of commercial or freeware models. They are RCPWAVE wave module, timeaveraged and depthintegrated current module, sediment transport module based on Bailard (1981) and contour change morphological module. Two different timescales and two staggered grid systems for hydrodynamic and morphological simulations were adopted alternatively. For shortterm 2D profile changes, new NLine model applicability has been examined using data from the laboratory to the field. For ideal beaches, new NLine can simulate an offshore storm bar generation or an onshore accretion due to high or low energy waves. For SUPERTANK largescale flume data, the predicted profile matched the measured profile well, especially the bar height and position. For beach profile data from the Gold Coast, storminduced variations of barred profiles were reasonably modelled. The new NLine model compared well with other commonly used crossshore models such as SBEACH and UNIBEST. A new schematisation for a nonmonotonic profile and DUNED inclusion were introduced. Sensitivity tests on crossshore sediment coefficient (Kq), smoothing parameter (??s) and water level fluctuations were performed. For longterm 3D beach changes, the new NLine model applicability has been tested with various boundary conditions using idealized and real field data. Two periods, 17 and 16 months, of beach changes before and after a major bypass plant commenced operation in 2001 at Letitia Spit were simulated. The profile and shoreline changes were predicted reasonably well. Empirical model parameters were determined after a range of sensitivity and calibration testing. The new NLine model showed its better performance compared to oneline models. It can handle various boundary conditions, especially bypass conditions. The NLine model is not only capable of modelling planform variations but also crossshore profile changes.

122 
A multidisciplinary approach to complex systems design.Ryan, Alex J. January 2007 (has links)
The design and management of organised systems, comprised of dynamic interdependent collectives of autonomous agents, is the kind of problem that the discipline of complex systems is intended to address. Nevertheless, conventional modelbased applications of complex systems may be of limited utility when the problem is also datapoor and soft. In this case, a quantitative model may be at best meaningless; at worst harmful. Systems approaches, such as soft systems methodologies, have been developed that provide some guidance in this domain. However, these alternatives do not utilise the exact techniques of complex systems, preferring to abandon mathematical representations altogether. It is the aim of this thesis to advance a “conceptual analysis" approach to complex systems design that exploits deep insights from the mathematics of complex systems, without building explicit models of the underlying system. It is argued that this approach can extend the domain of applicability of the discipline of complex systems into situations where quantitative data is unavailable, and human and social factors are significant. Conceptual analysis of complex systems is inherently multidisciplinary, because it is broader than the foundations of any single conventional discipline. This is reflected in the structure of this thesis, which spans the philosophy, theory and application of complex systems. Part I on systems philosophy develops an understanding of representation, which sheds light on the utility and limitations of models. The history of the systems movement is then surveyed, systemism is distinguished from both individualism and holism, and `system' is defined. Complex systems is contrasted with both early systems theory and contemporary systems approaches. Part II on complex systems theory firstly relates the major theoretical concepts within a rigourous information theoretical framework. They include complexity, edge of chaos, selforganisation, emergence, adaptation, evolution and self refer entiality. The central systems concept  emergence  is then examined in depth beyond its information theoretic interpretation, leading to a concise definition of emergent properties and emergence. A new framework for understanding emergence in terms of scope, resolution and state yields substantial novel insights. It is shown that emergence is coupled to scope, in contrast to the conventional explanation that relates levels of description. Part III applies the preceding philosophical and theoretical framework to realworld problems in the defence and security arena. In the first example, the theory of multiscale complexity reveals structural impediments to success for conventional force structures in asymmetric warfare, such as Operation Iraqi Freedom. The second example analyses the capability development process, which is responsible for transforming the security needs of Government into equipment purchasing decisions. The analysis produces practical recommendations for improvements that address the underlying complexity of the problem. Reflections in the conclusion of this thesis focus on the interrelations between philosophy, theory and application. As the individual contributions of this thesis are woven into a single tapestry, they demonstrate the utility of a multidisciplinary approach to complex systems design. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgibin/Pwebrecon.cgi?BBID=1283989 / Thesis(PhD)  University of Adelaide, School of Mathematical Sciences, 2007

123 
Reactiondiffusion models for dispersing and settling populations in biologyTrewenack, Abbey Jane January 2008 (has links)
We investigate reactiondiffusion models for populations whose members undergo two specific processes: dispersal and settling. Systems of this type occur throughout biological science, in contexts ranging from ecology to cell biology.Here we consider three distinct applications, namely: / • animal translocation, / • the invasion of a domain by precursor and differentiated cells, and / • the development of tissueengineered cartilage. / Mathematical modelling of these systems provides an understanding of the populationlevel patterns that emerge from the behaviour of individuals. / A multispecies reactiondiffusion model is developed and analysed for each of the three applications. We present numerical results, which are illuminated through analytical results derived for simplified or limiting cases. For these special cases, results are obtained using analytical techniques including perturbation analysis, travelling wave analysis and phase plane methods. These analytic results provide a more complete understanding of system behaviour than numerical results alone. Emphasis is placed on connecting modelling results with experimental observations. / The first application considered is animal translocations. Translocations are widely used to reintroduce threatened species to areas where they have disappeared. A variety of different dispersal and settling mechanisms are considered, and results compared. The model is applied to a case study of a double translocation of the Maud Island frog, Leiopelma pakeka. Results suggest that settling occurs at a constant rate, with repulsion playing a significantrole in dispersal. This research demonstrates that mathematical modelling of translocations is useful in suggesting design and monitoring strategies for future translocations, and as an aid in understanding observed behaviour. / The second application we investigate is the invasion of a domain by cells that migrate, proliferate and differentiate. The model is applicable to neural crest cell invasion in the developing enteric (intestinal) nervous system, but is presented in general terms and is of broader applicability. Regions of the parameter space are characterised according to existence, shape and speed of travelling wave solutions. Our observations may be used in conjunction with experimental results to identify key parameters determining the invasion speed for a particular biological system. Furthermore, these results may assist experimentalists in identifying the resource that is limiting proliferation of precursor cells. / As a third application, we propose a model for the development of cartilage around a single chondrocyte. The limited ability of cartilage to repair when damaged has led to the investigation of tissue engineering as a method for reconstructing cartilage. As in healthy cartilage, the model predicts a balance between synthesis, transport, binding and decay of matrix components. Our observations could explain differences observed experimentally between various scaffold media. Modelling results are also used to predict the minimum chondrocyte seeding density required to produce functional cartilage. / In summary, we develop reactiondiffusion models for dispersing and settling populations for three biological applications. Numerical and analytical results provide an understanding of populationlevel behaviour. This thesis demonstrates that mathematical modelling of biological systems can further understanding of biological systems and help to answer questions posed by experimental research.

124 
Advanced numerical modeling of the Lorentz mixing processHager, Michael B. 10 December 1996 (has links)
There are numerous techniques for improving the mixing of fuel and
oxidant species. However, many of these methods cannot be applied to combustion
systems due to material limitations. A means of mixing the reacting species without
physically invading the flow stream is therefore desired.
In this work, induced electromagnetic forces known as Lorentz forces are
considered as a means of enhancing the combustion of coflowing reactant streams. To
evaluate the effect of various parameters on the mixing process, a nondimensional
description is derived and used to develop a numerical model. Numerical experiments are
performed based on a three level BoxBehnken design in which the dimensionless Lorentz
force parameter, Reynolds number, and Euler number are varied.
The Lorentz force parameter has a large effect on the mixing process. The
Reynolds number has a minor effect on mixing, and the Euler number has a negligible
effect. Confirmation of these results through experimental work is needed. Approaches
that could be used to verify these results experimentally are outlined, and the construction
and testing of a burner suitable for further experiments on Lorentz mixing is described. / Graduation date: 1997

125 
Demand and profitability for albacore products : a multiattribute analysisGarciaMartinez, Salvador 18 September 1996 (has links)
The main purpose of this research is to provide the
commercial seafood industry of the Pacific Northwest
information on preferences of restaurateurs, retailers, and
wholesalers for whole albacore, lowvalue added albacore
products (chunks, medallions, and steaks), albacore loins,
and highvalue added albacore products (hot smoked and lox).
All of these products were categorized as nontraditional
market forms of albacore products, except whole albacore.
The empirical analysis was based on self explicated and
conjoint analysis. The demand models for albacore products
were estimated using weighted least squares. Profitability
equations for albacore products were estimated using a twolimit Tobit model. From the self explicated section, it was
found that the attributes of price, flavor, blood
spots/bruising, and bleeding of whole albacore were
considered highly important by respondents. From the
conjoint analysis section, it was found that, as expected a
priori, price had a statistical significant effect on the
demand and profitability models for all albacore products.
Other variables, such as location of the firm, type of firm,
experience with tuna species, and ranking of albacore had
statistical significant effects on the demand and
profitability equations. Wholesalers, restaurateurs, and
retailers agreed that quality is a major concern and will
influence their preferences when purchasing albacore
can products. Overall, the findings from this research
provide guidance to the commercial seafood industry of the
Pacific Northwest to enhance the markets for albacore
products. / Graduation date: 1997

126 
Coupled dynamics of bouys and mooring tethersIdris, Krisnaldi 19 May 1995 (has links)
Timedomain models were developed to predict the response of a tethered buoy
subject to hydrodynamic loadings. A coupled analysis of the interaction of a buoy and
its mooring is included and threedimensional response is assumed. External loadings
include hydrodynamic forces, tethers tensions, wind loadings and the weight of both
cable and buoy. System nonlinearities include, large rotational and translational
motions, and nonconservative fluid loadings.
The mooring problem is formulated as a nonlinear twopointboundaryvalueproblem.
The problem is then converted to a combine initialvalue and boundaryvalue
problem to a discrete boundaryvalue problem at particular time, using a Newmarklike
difference formula. At each instant in time the nonlinear boundaryvalue problem is
solved by direct integration and using a successive iterative algorithm, such that
boundary conditions are always satisfied.
Buoy equations of motion are derived by both a small angle assumption and a
large angle assumption. The small angle formulation uses the Eulerian angle for
rotational coordinates. Coupling between the buoy and cable is performed by adopting the buoy equations of motion as boundary conditions at one end for the mooring problem. The rotational coordinates for the large angle formulation are represented by Euler parameters. The large angle formulation is solved by a predictorcorrector type of time integration of buoy motions constrained by tether forces. Coupling between the buoy and moorings is then enforced through matching of the velocity of the tether attachment points on the buoy with velocity of the tether ends; the velocities of tether attachment points serve as boundary conditions for the various mooring cables attached. Multiple time steps are used to account for different sizes of integration time step required for stability of solution in the buoy and tether.
Numerical examples are provided to contrast the validity and capability of the formulations and solution techniques. Responses of three types of buoy (sphere, spar and disc) are predicted by the present models and compared to results obtained by experiments. Application of the present model to solve a multileg/multipoint mooring system is also provided. / Graduation date: 1996

127 
Dynamic latent variables path models : an alternative PLS estimationStrohe, Hans Gerhard January 1995 (has links)
In this paper a partial least squares (PLS) approach to dynamic modelling with latent variables is proposed. Let Y be a matrix of manifest variables and H the matrix of the corresponding latent variables. And let H = BH+ε be a structural PLS model with a coefficient matrix B. Then this model can be made a dynamic one by substituting for B a matrix F = B + CL containing the lag operator L. Then the structural dynamic model H = FH+ε is formally estimated like an ordinary PLS model. In an exploratory way the model can be used for forecasting purposes. The procedure is being programmed in ISP.

128 
Combining measurements with deterministic model outputs: predicting groundlevel ozoneLiu, Zhong 05 1900 (has links)
The main topic of this thesis is how to combine model outputs from deterministic models with measurements from monitoring stations for air pollutants or other meteorological variables. We consider two different approaches to address this particular problem.
The first approach is by using the Bayesian Melding (BM) model proposed by Fuentes and Raftery (2005). We successfully implement this model and conduct several simulation studies to examine the performance of this model in different scenarios. We also apply the melding model to the ozone data to show the importance of using the Bayesian melding model to calibrate the model outputs. That is, to adjust the model outputs for the prediction of measurements. Due to the Bayesian framework of the melding model, we can extend it to incorporate other components such as ensemble models, reversible jump MCMC for variable selection.
However, the BM model is purely a spatial model and we generally have to deal with spacetime dataset in practice. The deficiency of the BM approach leads us to a second approach, an alternative to the BM model, which is a linear mixed model (different from most linear mixed models, the random effects being spatially correlated) with temporally and spatially correlated residuals. We assume the spatial and temporal correlation are separable and use an AR process to model the temporal correlation. We also develop a multivariate version of this model.
Both the melding model and linear mixed model are Bayesian hierarchical models, which can better estimate the uncertainties of the estimates and predictions.

129 
Modified limiting dilution analysis : a mathematical model with biological interpretationMaier, Stefan H. 04 April 1994 (has links)
A mathematical model of Limiting Dilution Analysis for two limiting
parameters is presented and investigated. Limiting Dilution Analysis is a microbiological
cell assay developed for immunological application. In the given
case we deal with the interaction between B lymphocytes, macrophage derived
factor and Tindependent antigens. The state of the art is that quantitative
statements are only possible if one cell type (in general the B cells) is limiting
and all others are in excess present.
The basis for this thesis is a set of experiments in which B cells and
macrophage derived factor are limiting and all other involved cells and factors
are in saturating amounts present. It is shown that so far presented suggestions
on modeling Limiting Dilution Analysis for two limiting celltypes are not
suitable for this problem. Further, a mathematical model based on data is
presented and interpreted in immunological terms with the help of a set of
partial differential equations. The basis for the interpretation of the model
are changes in affinity and saturation effects, both not incorporated in the so
far presented models of the assay. In particular the relevance of mathematical
interpretation of this process for the identification of new concepts as the
saturation effects is stressed.
The model of partial differential equations is highly nonlinear but offers
the possibility of interpreting the highly interrelated processes apart from each
other. / Graduation date: 1994

130 
Agents' agreement and partial equilibrium pricing in incomplete marketsAnthropelos, Michail, 1980 25 September 2012 (has links)
We consider two riskaverse financial agents who negotiate the price of an illiquid indivisible contingent claim in an incomplete semimartingale market environment. Under the assumption that the agents are exponential utility maximizers with nontraded random endowments, we provide necessary and sufficient conditions for the negotiation to be successful, i.e., for the trade to occur. We, also, study the asymptotic case where the size of the claim is small compared to the random endowments and give a full characterization in this case. We, then, study a partialequilibrium problem for a bundle of divisible claims and establish its existence and uniqueness. A number of technical results on conditional indifference prices are provided. Finally, we generalize the notion of partialequilibrium pricing in the case where the agents' risk preferences are modelled by convex capital requirements. / text

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