vibration of beams with general boundary conditions due to a moving harmonic load the transverse vibrations of elastic homogeneous isotropic beams with general boundary conditions due to a moving random force with constant mean value are analyzed the boundary conditions considered are pinned pinned fixed fixed pinned fixed and fixed free based on the bernoulli beam theory the problem is described by means of a partial differential equation closed form solutions for the variance and the coefficient of variation of the beam deflection are obtained and compared for three types of force motion accelerated decelerated and uniform the effects of beam damping and speed of the moving force on the dynamic response of beams are studied in detail

vibration analysis of non linear beams subjected to a moving load using the finite element method this paper is concerned with the non linear vibration of immovably supported variable beams in which the geometric non linearity due to the axial force generated by stretching the middle surface is taken into account when the beam is subjected to a moving load the dynamic deflections of the beam are computed by using a galerkin finite element formulation and the time differential terms are integrated by using the implicit direct integration method three types of approximations for solving the non linear problem are considered in the first of which both the longitudinal deflections and inertia are considered with only the longitudinal deflections being considered and in the second neither the longitudinal deflections nor inertia in the third the results obtained by using these non linear models are numerically compared with that obtained by the linear model

random fixed point equations and inverse problems using collage method for contraction mappings abstract in this paper we are interested in the direct and inverse problems for the following class of random fixed point equations t w x w x w where t x x is a given operator is a probability space and x is a polish metric space the inverse problem is solved by recourse to the collage theorem for contractive maps we then consider two applications i random integral equations and ii random iterated function systems with greyscale maps rifsm for which noise is added to the classical ifsm

nonlinear dynamic analysis of an eccentrically prestressed damped beam under a concentrated moving harmonic load this paper focuses on the geometrically nonlinear dynamic analysis of an eccentrically prestressed simply supported damped beam subjected to a concentrated moving harmonic load the nonlinear dynamic deflections of the beam are obtained by polynomial functions the kelvin voigt model for the material of the beam is used two coupled nonlinear systems of equations of motion are derived using lagrange s equations under the assumptions of the euler bernoulli beam theory with the von karman s nonlinear strain displacement relationships the rotary inertia axial displacement and axial inertia are included in the formulation the nonlinear equations of motion are solved by using the implicit time integration method of newmark in conjunction with the newton raphson iteration method in this study the effects of large deflections the internal damping of the beam the velocity of the moving harmonic load the prestress load the eccentricity of the prestress load and the excitation frequency on the dynamic response of the beam are discussed the obtained results are compared with the results based on the linear beam theory convergence studies are performed numerical results show that the above mentioned effects play a very important role in the deflections of the beam

a fixed point theorem for condensing operators and applications to hammerstein integral equations in banach spaces abstract we prove a fixed point theorem of furi pera type for condensing operators this will then be used to establish the existence of solutions to certain integral equations of hammerstein type in banach spaces

vibration analysis of a non linear beam subjected to moving loads by using the galerkin method abstract this paper presents the analysis of dynamic deflections of a beam including the effects of geometric non linearity subjected to moving vehicle loads the beam is assumed to be elastic and simply supported with immovable ends and the vehicles are assumed to be single degree of freedom spring mass damper with the vehicles moving on the beam from one end to the other the dynamic reflections of the beam and vehicles are computed by using the galerkin method thus the dynamic deflections are assumed to be a set of time functions multiplied by approximate functions respectively and the time functions are numerically computed by solving the non linear differential equations by the newmark method

automatic target recognition by matching oriented edge pixels this paper describes techniques to perform efficient and accurate target recognition in difficult domains in order to accurately model small irregularly shaped targets the target objects and images are represented by their edge maps with a local orientation associated with each edge pixel three dimensional objects are modeled by a set of two dimensional 2 d views of the object translation rotation and scaling of the views are allowed to approximate full three dimensional 3 d motion of the object a version of the hausdorff measure that incorporates both location and orientation information is used to determine which positions of each object model are reported as possible target locations these positions are determined efficiently through the examination of a hierarchical cell decomposition of the transformation space this allows large volumes of the space to be pruned quickly additional techniques are used to decrease the computation time required by the method when matching is performed against a catalog of object models the probability that this measure will yield a false alarm and efficient methods for estimating this probability at run time are considered in detail this information can be used to maintain a low false alarm rate or to rank competing hypotheses based on their likelihood of being a false alarm finally results of the system recognizing objects in infrared and intensity images are given

a parametric level set based collage method for an inverse problem in elliptic partial differential equations in this work based on the collage theorem we develop a new numerical approach to reconstruct the locations of discontinuity of the conduction coefficient in elliptic partial differential equation

vibration of multi span non uniform beams under moving loads by using modified beam vibration functions based on hamilton s principle the vibration of a multi span non uniform beam subjected to a moving load is analysed by using modified beam vibration functions as the assumed modes the modified beam vibration functions satisfy the zero deflection conditions at all the intermediate point supports as well as the boundary conditions at the two ends of the beam numerical results are presented for both uniform and non uniform beams under moving loads of various velocities examples show that this method converges very quickly and good results are obtained

random fixed points of k set and pseudo contractive random maps abstract let be a measurable space x and y separable banach spaces and c a weakly compact subset of x let f c y and t c y be continuous random operators then the deterministic solvability of the equation f x t x 0 x c implies the stochastic solvability of it provided that f t is demiclosed at zero and t c is bounded for each as applications random fixed points of various types of pseudo contractive and k set contractive random operators are obtained

dynamic finite element analysis of a nonlinear beam subjected to a moving load abstract in this paper the deterministic and random vibration analysis of a nonlinear beam on an elastic foundation subjected to a moving load which may simulate railway track runway etc has been performed the effects of longitudinal deflection and inertia have been considered so that the coupled equations of longitudinal and transverse deflections can be derived based on bernoulli euler hypothesis the randomness of the beam profile has been considered in such a way that the mean line of the beam is variable with respect to position in the vertical plane and is superimposed by stochastic uncertainty and the moving load travels along the beam with constant velocity or acceleration the deterministic and statistical dynamic responses of the beam have been calculated by using the galerkin s method in conjunction with the finite element method and the derived nonlinear system differential equation has been solved by using the implicit direct integration method in particular the standard deviation of the transverse deflection of the nonlinear beam has been calculated and presented by using the monte carlo simulation technique also the distribution of the midpoint deflection of the beam has been investigated by using the probability paper plot

random fixed points of set valued maps some random fixed point theorems for set valued random operators under very mild conditions are established some recent results of o regan proc amer math soc 126 1998 3045 3053 and computers math applic 35 1998 27 34 are improved significantly the discussion in this paper underlines in addition to generality the unifying aspects of our result

approximate input sensitive algorithms for point pattern matching we study input sensitive algorithms for point pattern matching under various transformations and the hausdorff metric as a distance function given point sets p and q in the plane the problem of point pattern matching is to determine whether p is similar to some portion of q where p may undergo transformations from a group g of allowed transformations all algorithms are based on methods for extracting small subsets from q that can be matched to a small subset of p the runtime is proportional to the number k of these subsets let d be the number of points in p that are needed to define a transformation in g the key observation is that for some set b p of cardinality larger than d the number of subsets of q of this cardinality that match b is practically small as the problem becomes more constrained we present methods to extract efficiently all these subsets in q we provide algorithms for homothetic rigid and similarity transformations in the plane and give a general method that works for any dimension and for any group of transformations the runtime of our algorithms depends roughly linearly on the number of subsets k in addition to an nlogn factor thus our approximate matching algorithms run roughly in time o nlogn kmlogn where m and n are the number of points in p and q respectively the constants hidden in the big o vary depending on the group of transformations g

efficient algorithms for robust feature matching abstract one of the basic building blocks in any point based registration scheme involves matching feature points that are extracted from a sensed image to their counterparts in a reference image this leads to the fundamental problem of point matching given two sets of points find the affine transformation that transforms one point set so that its distance from the other point set is minimized because of measurement errors and the presence of outlying data points it is important that the distance measure between the two point sets be robust to these effects we measure distances using the partial hausdorff distance point matching can be a computationally intensive task and a number of theoretical and applied approaches have been proposed for solving this problem in this paper we present two algorithmic approaches to the point matching problem in an attempt to reduce its computational complexity while still providing a guarantee of the quality of the final match our first method is an approximation algorithm which is loosely based on a branch and bound approach due to huttenlocher and rucklidge technical report 1321 dept of computer science cornell university ithaca 1992 proc ieee conf on computer vision and pattern recognition new york 1993 pp 705 706 we show that by varying the approximation error bounds it is possible to achieve a tradeoff between the quality of the match and the running time of the algorithm our second method involves a monte carlo method for accelerating the search process used in the first algorithm this algorithm operates within the framework of a branch and bound procedure but employs point to point alignments to accelerate the search we show that this combination retains many of the strengths of branch and bound search but provides significantly faster search times by exploiting alignments with high probability this method succeeds in finding an approximately optimal match we demonstrate the algorithms performances on both synthetically generated data points and actual satellite images

vibrations of non uniform continuous beams under moving loads abstract the dynamic behavior of multi span non uniform beams transversed by a moving load at a constant and variable velocity is investigated the continuous beam is modelled using bernoulli euler beam theory the solution is obtained by using both the modal analysis method and the direct integration method the natural frequencies and mode shapes used in the solution of this problem are obtained exactly by deriving the exact dynamic stiffness matrices for any polynomial variation of the cross section along the beam using the exact element method the mode shapes are expressed as infinite polynomial series using the exact mode shapes yields the exact solution for general variation of the beam section in case of constant and variable velocity numerical examples are presented in order to demonstrate the accuracy and the effectiveness of the present study and the results are compared to previously published results

dynamic response of a beam with intermediate point constraints subject to a moving load abstract the transverse vibration of a beam with intermediate point constraints subject to a moving load is analyzed by using the euler beam theory and the assumed mode method the point constraints in the form of supports are assumed to be linear springs of large stiffness results of numerical simulations are presented for various combinations of constant axial velocity of the moving load and number of point constraints

using the collage method to solve odes inverse problems with multiple data sets abstract we consider inverse problems for ordinary differential equations odes where multiple noisy observational data sets are available the inverse problem for a single data set asks us to find an ode or system thereof that admits the interpolated data set as an approximate solution such an inverse problem can be cast within the framework of fixed point equations so that we seek to approximate the data values by a fixed point of an operator related to the odes the collage coding method replaces the minimization of this approximation error by the minimization of the so called collage distance the purpose of this paper is to formulate and explore various methods for dealing with the collection of collage distances corresponding to multiple noisy data sets we present three schemes averaging the parameter estimates obtained by minimizing each of the separate collage distances and two approaches arising from goal programming numerous examples are presented

vibration of multi span timoshenko beams to a moving force abstract a method of modal analysis is proposed in this paper to investigate the forced vibration of multi span timoshenko beams the ratio of the radius of gyration of the cross section to one span length is defined as a parameterr the effect ofron the first modal frequency of a beam is studied a concentrated force traversing on the beam is used as an example the effects of span number rotary inertia and shear deformation on the maximum moment the maximum deflection and the critical velocity of a beam are examined the results are compared with those of a multi span bernoulli euler beam

approximate geometric pattern matching under rigid motions we present techniques for matching point sets in two and three dimensions under rigid body transformations we prove bounds on the worst case performance of these algorithms to be within a small constant factor of optimal and conduct experiments to show that the average performance of these matching algorithms is often better than that predicted by the worst case bounds

precise time step integration for the dynamic response of a continuous beam under moving loads abstract the dynamic response of a non uniform continuous euler bernoulli beam is analyzed with hamilton s principle and the eigenpairs are obtained by the ritz method a high precision integration method is used to calculate the dynamic responses of this beam numerical results show that the method is more accurate in the prediction of the vibration responses under the moving loads than the newmark method

recognizing solid objects by alignment with an image in this paper we consider the problem of recognizing solid objects from a single two dimensional image of a three dimensional scene we develop a new method for computing a transformation from a three dimensional model coordinate frame to the two dimensional image coordinate frame using three pairs of model and image points we show that this transformation always exists for three noncollinear points and is unique up to a reflective ambiguity the solution method is closed form and only involves second order equations we have implemented a recognition system that uses this transformation method to determine possible alignments of a model with an image each of these hypothesized matches is verified by comparing the entire edge contours of the aligned object with the image edges using the entire edge contours for verification rather than a few local feature points reduces the chance of finding false matches the system has been tested on partly occluded objects in highly cluttered scenes

non linear vibration of timoshenko beam due to a moving force and the weight of beam the large deflection theory is employed to derive the equations of motion of the timoshenko beam due to the coupling effect of an external force with the weight of the beam galerkin s method is employed to obtain the dynamic responses of the beam a set of two discrete moving forces is taken as an example to investigate the characteristics of these responses results show that the effect of weight of the beam decreases the fundamental period of the structure further both the dynamic deflection and the dynamic moment of the beam predicated by the theory including the effect of weight of the beam are less than those of the beam predicated either by the small deflection theory or by the large deflection theory without including the effect of weight of the beam

efficiently locating objects using the hausdorff distance the hausdorff distance is a measure defined between two point sets here representing a model and an image the hausdorff distance is reliable even when the image contains multiple objects noise spurious features and occlusions in the past it has been used to search images for instances of a model that has been translated or translated and scaled by finding transformations that bring a large number of model features close to image features and vice versa in this paper we apply it to the task of locating an affine transformation of a model in an image this corresponds to determining the pose of a planar object that has undergone weak perspective projection we develop a rasterised approach to the search and a number of techniques that allow us to locate quickly all transformations of the model that satisfy two quality criteria we can also efficiently locate only the best transformation we discuss an implementation of this approach and present some examples of its use

random fixed point theorems and approximation in cones a very general random fixed point theorem is first proved as applications some random approximation theorems and random fixed point theorems are obtained recent results due to itoh j math anal appl 67 1979 261 273 lin proc amer math soc 103 1988 502 506 and xu proc amer math soc 110 1990 495 500 either are improved or are direct consequences of our results the stochastic versions of the recent results of lin 1988 and li proc amer math soc 97 1986 277 280 are also given

moving forces identification on a multi span continuous bridge abstract a continuous bridge is modelled as a multi span continuous timoshenko beam with non uniform cross section the vibration behaviour of this beam subjected to moving loads is analyzed by hamilton s principle with the intermediate point constraints represented by very stiff linear springs a method based on the modal superposition and optimization technique is developed to identify the moving forces in the time domain the damped least squares method is used in the identification to provide bounds to the results the errors in the moving force identification are discussed in the paper both computation simulations and laboratory tests show that the method is effective for identifying the moving loads using different combinations of measured responses

vibration of viscoelastic beams subjected to an eccentric compressive force and a concentrated moving harmonic force abstract the problem of lateral vibration of a beam subjected to an eccentric compressive force and a harmonically varying transverse concentrated moving force is analyzed within the framework of the bernoulli euler beam theory the lagrange equations are used to examine the free vibration characteristics of an axially loaded beam and the dynamic response of a beam subjected to an eccentric compressive force and a moving harmonic concentrated force the constraint conditions of supports are taken into account by using the lagrange multipliers in the study trial function denoting the deflection of the beam is expressed in a polynomial form by using the lagrange equations the problem is reduced to the solution of a system of algebraic equations results of numerical simulations are presented for various combinations of the value of the eccentricity the eccentric compressive force excitation frequency and the constant velocity of the transverse moving harmonic force convergence studies are made the validity of the obtained results is demonstrated by comparing them with exact solutions based on the bernoulli euler beam theory obtained for the special cases of the investigated problem

solution of an inverse problem for fractals and other sets abstract the problem of providing succinct approximate descriptions of given bounded subsets of rn can be solved by application of the contraction mapping principle

inverse problems for random differential equations using the collage method for random contraction mappings in this paper we are concerned with differential equations with random coefficients which will be considered as random fixed point equations of the form t w x w x w w w here t wxx x is a random integral operator w f p is a probability space and x is a complete metric space we consider the following inverse problem for such equations given a set of realizations of the fixed point of t possibly the interpolations of different observational data sets determine the operator t or the mean value of its random components as appropriate we solve the inverse problem for this class of equations by using the collage theorem for contraction mappings