With the development of consumer electronics, the circuitry structure become more complex, For this reason, it might cause numerical errors to be cumulated in the simulation using the numerical electromagnetic algorithm, and result in simulated divergence or error. The two reasons of numerical error are passivity and causality, which priginate from the defect in the numerical calculation. In this thesis, for this problem, investigate the numerical compensation method for passivity, The occurrence of passive will make the frequency point of power is negative, this will makes the system divergence, Improve this problem, passivity verification and enforcement by eigenvalue in the Y-parameter, in the S-parameter by the singular value, causality conditions must be match with the imaginary part and the real part relationship, such as the Hilbert transform or the Kramer-Kronig relation, can be used to make causal verification and enforcement. Through some numerical methods, used simulation software such as: HFSS, ADS simulation of the microwave circuit model extraction, modified singular value, eigenvalue, and reached to reduce the numerical error, let it satisfy the convergence and avoid incorrect results, and minimize the impact of the initial data, does not change the characteristics of the original module, but also to solve the passive and the issue of causality.

Since uncertainty exists inevitably in control systems, it is questionable whether the controller, designed to compensate a nominal plant well, still guarantees the criteria of robust stability and robust H¡Û performance for the perturbed plant. In this thesis, controller parameters tuning based on the sensitivity concept of structured singular value, called £g-sensitivity, will be adopted to do the parameter adjustment so that, when the influence of uncertainty is considered, the robust stability and robust performance properties of the nominal closed-loop system will be preserved. In view of the time consuming effect of numerical computation and the misjudgment due to discontinuity problem involved in the £g-sensitivity analysis, this thesis proposes the sensitivity concept of skewed structured singular value, called £h-sensitivity, to remedy these drawbacks. Finally, the feasibility of the £h-sensitivity based controller parameters tuning technique is verified by the simulation results of two examples.

Thesis (Ph. D.)--Lehigh University, 2001. / Includes vita. Includes bibliographical references (leaves 93-101).

No description available.

The paper is devoted to asymptotic analysis of the Dirichlet problem for a second order partial differential equation containing a small parameter multiplying the highest order derivatives. It corresponds to a small perturbation of a dynamical system having a stationary solution in the domain. We focus on the case where the trajectories of the system go into the domain and the stationary solution is a proper node.

Thesis (Ph. D.)--University of Chicago, Department of Mathematics, June 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, Dept. of Mathematics, August 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1996. / Vita. Abstract. Includes bibliographical references (leaves 90-92). Also available via the Internet.

Thesis (Ph. D.)--Oregon State University, 1994. / Typescript (photocopy). Includes bibliographical references (leaves 41-45). Also available on the World Wide Web.

Submitted by Kleber Silva (kleberbs@ufba.br) on 2016-06-07T19:30:31Z No. of bitstreams: 1 KatiaRocha_dissert_princ.pdf: 1219624 bytes, checksum: b704a7f90a949d7d84aeea89e1a5853c (MD5) / Approved for entry into archive by Alda Lima da Silva (sivalda@ufba.br) on 2016-06-13T17:18:45Z (GMT) No. of bitstreams: 1 KatiaRocha_dissert_princ.pdf: 1219624 bytes, checksum: b704a7f90a949d7d84aeea89e1a5853c (MD5) / Made available in DSpace on 2016-06-13T17:18:45Z (GMT). No. of bitstreams: 1 KatiaRocha_dissert_princ.pdf: 1219624 bytes, checksum: b704a7f90a949d7d84aeea89e1a5853c (MD5) / Provaremos que um atrator Hiperbólico - singular de um fluxo 3-dimensional e caótico sob dois pontos de vista diferentes. Primeiro provaremos que o fluxo e expansivo,isto e, se dois pontos permanecem próximos por todo tempo, então suas órbitas coincidem.O segundo objetivo e a existência de uma medida física suportada no atrator