Parametric excitation of the DWSC (Deep Water Stable Craneship) is studied in this thesis. It occurs for a system without any external forcing, when one of the coefficients in the equation of motion (EOM) modeling the system varies with time. Parametric instability might be triggered for certain values of the parameters describing the time-varying coefficient. The DWSC, basically a stepped classic spar with a catamaran as its deck, because of certain unique features, may be susceptible to parametric excitation. This thesis examines the phenomenon of parametric excitation with respect to roll motion in head seas, using time-domain simulation and stability analysis. It examines the DWSC's susceptibility to parametric instability using the same methods of analysis and the effect of damping (especially viscous drag) on parametric excitation and instability. The thesis uses Mathieu's equation as the basis for stability analysis and time-simulates the coupled heave-sway-roll EOM. Time-domain simulation is done for two reasons: firstly for determining the variation in roll stiffness because of a regular wave (the variation in roll stiffness is an input to the stability analysis) and secondly for simulating the coupled heave-sway-roll EOM. Both time-domain analysis and stability analysis are done for sea states of interest and for examining interesting phenomena like roll resonance (due to body-wave interaction) and parametric instability. Results highlight: 1) a "cancellation frequency" in the heave wave exciting force; 2) the effect of viscous drag on coupled heave-sway-roll motions; 3) time-simulations validating the stability analysis; 4) the trend of stability with increasing sea states, wave periods and amplitudes; 5) characteristics of parametric instability; 6) the methodology used to predict or detect parametric instability and 7) the effect of viscous drag on parametric instability.

Thesis--M. Sc.(Eng.), University of Hong Kong. / Mimeographed.

Parametric excitation is a fundamental feature of dynamical systems arising across the applied sciences. In this thesis we study the structure of parametric res- onance and its in uence of the global nonlinear dynamics in a number of oscillating systems which arise in engineering contexts. The parametrically excited Helmholtz oscillator and the elliptically excited pen- dulum are two systems where the interaction of regular and parametric excitation are important for a complete understanding of the dynamics. We examine the resonance structure of the Helmholtz oscillator and use the Melnikov function to demonstrate the e ect that the parametric excitation has on the nonlinear dynam- ics. The estimates produced in this analysis are then compared to a numerical study of the engineering integrity. For the elliptically excited pendulum we discuss the quantitative e ects of introducing ellipticity to the pro le of excitation. We go on to examine the e ect of periodic time varying mass in the Helmholtz oscillator and demonstrate that the resonance structure exhibits the phenomenon of coexistence. The evolution of the systems engineering integrity is examined and compared to the purely parametrically excited case. Finally we examine a system incorporating two pendulums on a rigid rig modelled by two linear springs. The parametric resonance in this case is mapped using numerical Floquet theory and the structure of the linear resonance is shown to organise solution space for the nonlinear system.

This thesis explores the intersection between computation and architectural design. The thesis first develops several computational design tools, specifically focussing on three problem domains: (1) speedy generation and modification of architectural schemes sharing a common typological language, (2) analysis of urban and neighbourhood conditions, and (3) performance modelling and prediction
. To test the tools, the thesis subsequently applies the tools to design several variations of a condominium tower in downtown Toronto. Despite some limitations, the computational toolkit proved powerful and flexible enough to generate viable condominium schemes under various sets of assumptions.

This thesis represents an attempt to generalize the classical Theory of Optimal Design to popular regression models, based on Rational and Spline approximations. The problem of finding optimal designs for such models can be reduced to solving certain minimax problems. Explicit solutions to such problems can be obtained only in a few selected models, such as polynomial regression. Even when an optimal design can be found, it has, from the point of view of modern nonparametric regression, certain drawbacks. For example, in the polynomial regression case, the optimal design crucially depends on the degree m of approximating polynomial. Hence, it can be used only when such degree is given/known in advance. We present a partial, but practical, solution to this problem. Namely, the so-called Super Chebyshev Design has been found, which does not depend on the degree m of the underlying polynomial regression in a large range of m, and at the same time is asymptotically more than 90% efficient. Similar results are obtained in the case of rational regression, even though the exact form of optimal design in this case remains unknown. Optimal Designs in the case of Spline Interpolation are also currently unknown. This problem, however, has a simple solution in the case of Cardinal Spline Interpolation. Until recently, this model has been practically unknown in modern nonparametric regression. We demonstrate the usefulness of Cardinal Kernel Spline Estimates in nonparametric regression, by proving their asymptotic optimality, in certain classes of smooth functions. In this way, we have found, for the first time, a theoretical justification of a well known empirical observation, by which cubic splines suffice, in most practical applications. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2007-07-18 16:06:06.767

No description available.

No description available.

Modular building systems that use only prefabricated parts, sometimes known as building “kits”, first emerged in the 1830s and 1840s in the form of glass and iron roof systems for urban transportation and distribution centers and multi-storey facade systems. Kit systems are still used widely today in the form of curtain wall assemblies for office and condominium towers, yet in all this time the formal flexibility of these systems (their ability to form complex shapes) has not increased greatly. This is in large part due to the fact that the systems still rely on mass-produced components. This lack of flexibility limits the degree to which these systems can be customized for particular contexts and optimized for such things as daylighting or energy efficiency. Digital design and fabrication tools now allow us to create highly flexible building facade systems that can be customized for different contexts as well as optimized for particular performance objectives. This thesis develops a prototype for a flexible facade system using parametric modeling tools. The first part of the thesis looks at how parametric modeling can be used to facilitate building customization and optimization by integrating the acts of design, analysis, fabrication and construction. The second part of the thesis presents the facade system prototype and documents key aspects of its development. The facade system is modeled in Grasshopper 3D, a parametric modeling plug-in for Rhinoceros 3D. The model has built-in analysis tools to help the user optimize the facade for daylighting, energy efficiency, or views within any given context, as well as tools that alert the designer when fabrication or construction constraints are being violated.

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 69-72) Also available in print.

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2002. / Thesis advisor(s): Bruce Denardo, Andres Larraza. Includes bibliographical references (p. 55). Also available online.