investigation of equivalent system modeling and dynamic characteristics using reduced models animproved approach of updating theinitial e niteelementmodelsincomparison with amodaltestispresented this is accomplished by using the reduced models dynamically equivalent to the initial models the degrees of freedom dof in the reduced models include the generalized coordinates besides the measurement points for a modal test therefore these reduced models can take into account the inertia force at unmeasured dof and preserve the dynamic characteristics of the initial analytical models regardless of the measurement points these reduced models are used for a direct analysis experiment correlation with modal test data numerical simulation resultsarepresentedto showtheeffectivenessofthesereducedmodelsintheparametriccorrectionoftheanalytical e nite element models nomenclature k guyan reduced stiffness matrix ka nominal stiffness matrix of the initial e nite element model kb stiffness matrix for exactly modeled parts in the initial e nite element model k j jth submatrix for the assumed stiffness in the initial e nite element model kk stiffness matrix of the test models of k degreesof freedom dof kk stiffness matrix of the present tam of k dof kn stiffness matrix of the initial e nite element models of n dof kn stiffness matrix of the craig bampton e nite element models of n dof m guyan reduced mass matrix

riemann stieltjes operators and multipliers on q p spaces in the unit ball of c n this paper is devoted to characterizing the riemann stieltjes operators and pointwise multipliers acting on mobius invariant spaces q p which unify bmoa and bloch space in the scale of p the boundedness and compactness of these operators on q p spaces are determined by means of an embedding theorem i e q p spaces boundedly embedded in the non isotropic tent type spaces t q infinity c 2010 elsevier inc all rights reserved

multipliers of mobius invariant qs spaces the spaceqs 0 s consists of those f which are analytic in the unit disc mathbb d and such that sup a in mathbb d int limits mathbb d f z 2 1 varphi a z 2 s da z infty where varphi a z frac a z 1 overline a z we give a complete description of m qs the algebra of pointwise multipliers of qs by proving xiao s conjecture which says that f m qs if and only if f h and sup a in mathbb d left rm log frac 2 1 a right 2 int limits mathbb d f z 2 1 varphi a z 2 s da z infty

existence of lipschitz and semiconcave control lyapunov functions given a locally lipschitz control system which is globally asymptotically controllable at the origin we construct a control lyapunov function for the system which is lipschitz on bounded sets and we deduce the existence of another one which is semiconcave and so locally lipschitz outside the origin the proof relies on value functions and nonsmooth calculus

on brockett s condition for smooth stabilizability and its necessity in a context of nonsmooth feedback the necessity of brockett s condition for stabilizability of nonlinear systems by smooth feedback is shown by an argument based on properties of a degree for set valued maps to persist when the class of controls is enlarged to include discontinuous feedback

asymptotic controllability implies feedback stabilization it is shown that every asymptotically controllable system can be globally stabilized by means of some discontinuous feedback law the stabilizing strategy is based on pointwise optimization of a smoothed version of a control lyapunov function iteratively sending trajectories into smaller and smaller neighborhoods of a desired equilibrium a major technical problem and one of the contributions of the present paper concerns the precise meaning of solution when using a discontinuous controller

optimum approximation for residual stiffness in linear system identification a new method of system identification uti 1 i zes projector m atrix theory and the moorepenrose generalized inverse to derive an analytical stiffness matrix which when combined with the analytical mass matrix will more closely p redict modal test results weighting matrices a re used to enforce connectivity and make weighted corrections to the original analytical stiffness matrix a simple and straightforward mathematical formulation is obtained the method is compared and contrasted with other methods found in the literature and a simple numerical example is presented

feedback stabilization and lyapunov functions given a locally defined nondifferentiable but lipschitz lyapunov function we employ it in order to construct a discontinuous feedback law which stabilizes the underlying system to any given tolerance a converse result shows that suitable lyapunov functions of this type exist under mild assumptions we also establish that the feedback in question possesses a robustness property relative to measurement error despite the fact that it may not be continuous

characterizations of bergman spaces and bloch space in the unit ball of c n in this paper we prove that in the unit ball b of c a holomorphic function f is in the bergman space lp b 0 p 00 if and only if lvf z j21f z 1p 2 l izi2 n 1 da z 0 where v and a denote the invariant gradient and invariant measure on b respectively further we give some characterizations of bloch functions in the unit ball b including an exponential decay characterization of bloch functions we also give the analogous results for bmoa ab functions in the unit ball

stiffness matrix adjustment using mode data a procedure is introduced that uses in addition to mode data structural connectivity information to optimally adjust deficient stiffness matrices the adjustments performed are such that the percentage change to each stiffness coefficient is minimized the physical configuration of the analytical model is preserved and the adjusted model will exactly reproduce the modes used in the identification the theoretical development is presented and the procedure is demonstrated by numerical simulation of a test problem

on stabilisability of nonlinear systems on time scales in this article stabilisability of nonlinear finite dimensional control systems on arbitrary time scales is studied the classical results on stabilisation of nonlinear continuous time and discrete time systems are extended to systems on arbitrary time scales with bounded graininess function it is shown that uniform exponential stability of the linear approximation of a nonlinear system implies uniform exponential stability of the nonlinear system then this result is used to show a similar implication for uniform exponential stabilisability

pointwise multipliers and decomposition theorems in f q s in this paper we give a characterization of the pointwise multipliers of the holomorphic triebel lizorkin spaces f q s and we apply these results to prove a corona decomposition theorem for these spaces

compact composition operators on besov spaces we give a carleson measure characterization of the compact composition operators on besov spaces we use this characterization to show that every compact composition operator on a besov space is compact on the bloch space finally we give conditions that guarantee that the converse holds

the qp carleson measure problem let be a nonnegative borel measure on the open unit disk this note shows how to decide that the mobius invariant space covering and is boundedly resp compactly embedded in the quadratic tent type space interestingly the embedding result can be used to determine the boundedness resp compactness of the volterra type and multiplication operators on

lyapunov and feedback characterizations of state constrained controllability and stabilization a standard control system is considered in conjunction with a state constraint s and a target set the properties of open loop s constrained control to and practical closed loop s constrained control to are shown to be equivalent and to be characterizable in terms of the existence of certain types of control lyapunov functions feedback s constrained stabilizability to can be added to the list of equivalences when a small time controllability property is posited

pointwise multipliers from dirichlet type spaces dτ to qp spaces in the unit ball of cn abstract in this paper the pointwise multipliers m d q p and m d q p 0 are characterized in the unit ball of c n for the values of p in the three cases i n n 1 n p 1 ii n n 1 n p 1 and iii n n 1 n p 1 in particular the multiplier spaces m d bmoa and m d vmoa are discussed correspondingly for all and the sharp embeddings of m d n bmoa and m d n vmoa in bloch spaces are shown respectively

asymptotic stability and smooth lyapunov functions abstract we establish that differential inclusions corresponding to upper semicontinuous multifunctions are strongly asymptotically stable if and only if there exists a smooth lyapunov function since well known concepts of generalized solutions of differential equations with discontinuous right hand side can be described in terms of solutions of certain related differential inclusions involving upper semicontinuous multifunctions this result gives a lyapunov characterization of asymptotic stability of either filippov or krasovskii solutions for differential equations with discontinuous right hand side in the study of weak as opposed to strong asymptotic stability the existence of a smooth lyapunov function is rather exceptional however the methods employed in treating the strong case of asymptotic stability are applied to yield a necessary condition for the existence of a smooth lyapunov function for weakly asymptotically stable differential inclusions this is an extension to the context of lyapunov functons of brockett s celebrated covering condition from continuous feedback stabilization theory

higher radial derivative of functions of qp spaces and its applications in this paper we give some characterizations of the integral and carleson type measure both associated with higher radial derivative for holomorphic functions of q p 0 and q p spaces in the unit ball of c n as applications some sharp forms of the relations between dirichlet type spaces and q p 0 spaces are shown by means of higher radial derivative carleson type measure and constructive methods for the cases of determinism and randomization respectively

improvement of a large analytical model using test data a method has been developed which uses measured normal modes and natural frequencies to improve an analytical mass and stiffness matrix model of a structure the method directly identifies without iteration a set of minimum changes in the analytical matrices which force the eigensolutions to agree with the test measurements an application is presented in which the analytical model had 508 degrees of freedom and 19 modes were measured at 101 locations on the structure the resulting changes in the model are judged to be small compared to expectations of error in the analysis thus the improved model is accepted as a reasonable model of the structure with improved dynamic response characteristics in addition it is shown that the procedure may be a useful tool in identifying apparent measured modes which are not true normal modes of the structure nomenclature analytical matrix matrix of changes identity matrix full improved stiffness and mass matrices n x n full analytical k m matrices n x n partitions of ka ma corresponding to test coordinates partitions of ka ma corresponding to coupling elements partitions of ka ma corresponding to unmea sured coordinates number of measured modes number of degrees of freedom in the model measures of changes eqs 15 17 matrix norm sum of the squares of all the elements rectangular modal matrix normalized n x m th mode th column of measured and unmeasured partitions of diagonal matrix of measured natural frequencies m xm natural frequency of th mode 12 17 sum of the squares of all elements of matrix

some new function spaces and their applications to harmonic analysis abstract in this paper a family of spaces is introduced which seems well adapted for the study of a variety of questions related to harmonic analysis and its applications these spaces are the tent spaces they provide the natural setting for the study of such things as maximal functions the relevant space here is t p and also square functions where the space t2p is relevant as such these spaces lead to unifications and simplifications of some basic techniques in harmonic analysis thus they are closely related to lp and hardy spaces important parts of whose theory become corollaries of the description of tent spaces also as proc conf harmonic analysis cortona lect notes in math vol 992 springer verlag berlin new york 1983 already indicated where these spaces first appeared explicitly the tent spaces can be used to simplify some of the results related to the cauchy integral on lipschitz curves and multilinear analysis in retrospect one can recognize that various ideas important for tent spaces had been used if only implicitly for quite some time here one should mention carleson s inequality its simplifications and extensions the theory of hardy spaces and atomic decompositions

carleson measures multipliers and integration operators for spaces of dirichlet type for 0 1 we let d p denote the space of those functions f which are analytic in the unit disc d z c z 1 and satisfy d 1 z 2 f z p dx dy in this paper we characterize the positive borel measures in d such that d p l q d 0 p q we also characterize the pointwise multipliers from d p to d q 0 p q i fp 2 p in particular we prove that if

submatrix approach to stiffness matrix correction using modal test data an efficient method six stiffness matrix correction to match modal testing data is presented significant reduction of unknown parameters is achieved by grouping the elements of the same stiffness characteristics and representing them as a multiplication of a scaling factor and a submatrix a concise formulation to identify the scaling factors is found by utilizing a least squares solution the formulation also incorporates a capability of reducing finite element mass and stiffness matrices to test degrees of freedom for a direct analysis experiment correlation

global asymptotic controllability implies input to state stabilization the main problem addressed in this paper is the design of feedbacks for globally asymptotically controllable gac control affine systems that render the closed loop systems input to state stable iss with respect to actuator errors extensions for fully nonlinear gac systems with actuator errors are also discussed our controllers have the property that they tolerate small observation noise as well