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Full System (full + system)
Selected AbstractsA reduced-order modeling technique for tall buildings with active tuned mass damperEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2001Zu-Qing Qu Abstract It is impractical to install sensors on every floor of a tall building to measure the full state vector because of the large number of degrees of freedom. This makes it necessary to introduce reduced-order control. A kind of system reduction scheme (dynamic condensation method) is proposed in this paper. This method is iterative and Guyan condensation is looked upon as an initial approximation of the iteration. Since the reduced-order system is updated repeatedly until a desired one is obtained, the accuracy of the reduced-order system resulting from the proposed method is much higher than that obtained from the Guyan condensation method. Another advantage of the method is that the reduced-order system is defined in the subspace of the original physical space, which makes the state vectors have physical meaning. An eigenvalue shifting technique is applied to accelerate the convergence of iteration and to make the reduced system retain all the dynamic characteristics of the full system within a given frequency range. Two schemes to establish the reduced-order system by using the proposed method are also presented and discussed in this paper. The results for a tall building with active tuned mass damper show that the proposed method is efficient for the reduced-order modelling and the accuracy is very close to exact only after two iterations. Copyright © 2001 John Wiley & Sons, Ltd. [source] Robust trajectory tracking for a scale model autonomous helicopterINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2004Robert Mahony Abstract This paper considers the question of obtaining an a priori bound on the tracking performance, for an arbitrary trajectory, of closed-loop control of an idealized model of a scale model autonomous helicopter. The problem is difficult due to the presence of small body forces that cannot be directly incorporated into the control design. A control Lyapunov function is derived for an approximate model (in which the small body forces are neglected) using backstepping techniques. The Lyapunov function derived is used to analyse the closed-loop performance of the full system. A theorem is proved that provides a priori bounds on initial error and the trajectory parameters (linear acceleration and its derivatives) that guarantees acceptable tracking performance of the system. The analysis is expected to be of use in verification of trajectory planning procedures. Copyright © 2004 John Wiley & Sons, Ltd. [source] KERIS: evolving software with extensible modulesJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 5 2005Matthias ZengerArticle first published online: 26 SEP 200 Abstract We present the programming language KERIS, an extension of Java with explicit support for software evolution. KERIS introduces extensible modules as the basic building blocks for software. Modules are composed hierarchically, explicitly revealing the architecture of systems. A distinct feature of the module design is that modules do not get linked manually. Instead, the wiring of modules gets inferred. The module assembly and refinement mechanism of KERIS is not restricted to the unanticipated extensibility of atomic modules. It also allows extensions of already linked systems by replacing selected submodules with compatible versions without needing to re-link the full system. Extensibility is type-safe and non-invasive, i.e., the extension of a module preserves the original version and does not require access to source code. Copyright © 2005 John Wiley & Sons, Ltd. [source] A comparison of quantum chemical models for calculating NMR shielding parameters in peptides: Mixed basis set and ONIOM methods combined with a complete basis set extrapolationJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 7 2006Seongho Moon Abstract This article compares several quantum mechanical approaches to the computation of chemical shielding tensors in peptide fragments. First, we describe the effects of basis set quality up to the complete basis set (CBS) limit and level of theory (HF, MP2, and DFT) for four different atoms in trans N -methylacetamide. For both isotropic shielding and shielding anisotropy, the MP2 results in the CBS limit show the best agreement with experiment. The HF values show quite a different tendency to MP2, and even in the CBS limit they are far from experiment for not only the isotropic shielding of carbonyl carbon but also most shielding anisotropies. In most cases, the DFT values differ systematically from MP2, and small basis-set (double- or triple-zeta) results are often fortuitously in better agreement with the experiment than the CBS ones. Second, we compare the mixed basis set and ONIOM methods, combined with CBS extrapolation, for chemical shielding calculations at a DFT level using various model peptides. From the results, it is shown that the mixed basis set method provides better results than ONIOM, compared to CBS calculations using the nonpartitioned full systems. The information studied here will be useful in guiding the selection of proper quantum chemical models, which are in a tradeoff between accuracy and cost, for shielding studies of peptides and proteins. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 825,836, 2006 [source] | ||||||||||