transverse vibrations of tensioned pipes conveying fluid with time dependent velocity abstract in this study the transverse vibrations of highly tensioned pipes with vanishing flexural stiffness and conveying fluid with time dependent velocity are investigated two different cases the pipes with fixed fixed end and fixed sliding end conditions are considered the time dependent velocity is assumed to be a harmonic function about a mean velocity these systems experience a coriolis acceleration component which renders such systems gyroscopic the equation of motion is derived using hamilton s principle and solved analytically by direct application of the method of multiple scales a perturbation technique the natural frequencies are found increasing the ratio of fluid mass to the total mass per unit length increases the natural frequencies the principal parametric resonance cases are investigated in detail stability boundaries are determined analytically it is found that instabilities occur when the frequency of velocity fluctuations is close to two times the natural frequency of the constant velocity system when the velocity fluctuation frequency is close to zero no instabilities are detected up to the first order of perturbation numerical results are presented for the first two modes

dynamic scaling of disordered ising systems the critical dynamics of site disordered three dimensional ising systems has been studied by conventional local dynamics simulations investing 1015 single spin flips the author has verified that the correlation functions of disordered ising systems obey dynamic scaling behaviour the dynamic scaling functions have been calculated the critical exponent z appears to be strongly dependent on the degree of disorder the author has shown that this dependence arises from a crossover phenomenon which has been detected in the static critical behaviour the dynamical exponent has been estimated to be z 2 4 or 0 1 which is surprisingly near to the renormalization group result in o in 1 2

local and cluster critical dynamics of the 3d random site ising model abstract we present the results of monte carlo simulations for the critical dynamics of the three dimensional site diluted quenched ising model three different dynamics are considered these correspond to the local update metropolis scheme as well as to the swendsen wang and wolff cluster algorithms the lattice sizes of l 10 96 are analysed by a finite size scaling technique the site dilution concentration p 0 85 was chosen to minimize the correction to scaling effects we calculate numerical values of the dynamical critical exponents for the integrated and exponential autocorrelation times for energy and magnetization as expected cluster algorithms are characterized by lower values of dynamical critical exponent than the local one also in the case of dilution critical slowing down is more pronounced for the metropolis algorithm however the striking feature of our estimates is that they suggest that dilution leads to decrease of the dynamical critical exponent for the cluster algorithms this phenomenon is quite opposite to the local dynamics where dilution enhances critical slowing down

on the transversal vibrations of a conveyor belt with a low and time varying velocity part ii the beam like case in this paper initial boundary value problems for a linear wave string equation are considered these problems can be used as simple models to describe the vertical vibrations of a conveyor belt for which the velocity is small with respect to the wave speed and is assumed to move with a time varying speed formal asymptotic approximations of the solutions are constructed to show the complicated dynamical behavior of the conveyor belt it will also be shown that the truncation method cannot be applied to this problem in order to obtain approximations valid on long time scales

critical behavior of a three dimensional random bond ising model using finite time scaling with extensive monte carlo renormalization group method we have investigated the critical behavior of a three dimensional random bond ising model for a series of the disorder strength by a finite time scaling combining with monte carlo renormalization group method in the presence of a linearly varying temperature the method enables us to estimate a lot of critical exponents of both static and dynamic nature independently as well as the critical temperatures the static exponents obtained agree well with most existing results verify both the hyperscaling and the rushbrooke scaling laws and their combined scaling law which in turn validate their asymptotic nature and corroborate the universality of the relevant random fixed point with respect to the forms of disorder the dynamic critical exponent z is estimated to 2 114 51 which is compatible with those obtained from experiments and renormalization group analyses the exponents at low and high disorder strengths do not satisfy all scaling laws and are argued to be crossover exponents that reflect crossover from the random fixed point to the pure and the percolation fixed point they also indicate that the exponents that were previously suggested to be a distinct universality class for strong disorder strength in the literature may be just crossover our results demonstrate the effectiveness of the finite time scaling method

reflection and damping properties for semi infinite string equations with non classical boundary conditions abstract in this paper initial boundary value problems for a linear wave string equation are considered the main objective is to study boundary reflection and damping properties of waves in semi infinite strings this problem is of considerable practical interest in the context of vibration suppression at boundaries of elastic structures solutions of wave equations will be constructed for two different classes of boundary conditions in the first class a massless system consisting of a spring and damper will be considered at the boundary in the second class an additional mass will be added to the system at the boundary the d alembert method will be used to construct explicit solutions of the boundary value problem for the one dimensional wave equation on the semi infinite domain it will also be shown how waves are damped and reflected at these boundaries and how much energy is dissipated at the boundary

relative information of type s csiszar s f divergence and information inequalities during past years dragomir has contributed a lot of work providing different kinds of bounds on the distance information and divergence measures in this paper we have unified some of his results using the relative information of type s and relating it with the csiszar s f divergence

critical slowing down in local dynamics simulations the author reports some universal and non universal aspects of the critical dynamics of the three dimensional ising model obtained in extensive monte carlo finite size simulations the author shows that the time dependence of the magnetization of finite lattices is composed of two kinds of fluctuations at the critical point i phase fluctuations from one metastable minimum of the free energy to the other dominating the long time behaviour of the magnetization ii critical fluctuations inside each minimum decaying on a comparatively short timescale both kinds of fluctuations show up the same critical exponent z 2 10 or 0 02 which is also in excellent agreement with the exponent z of energy fluctuations

information divergence and risk for binary experiments we unify f divergences bregman divergences surrogate regret bounds proper scoring rules cost curves roc curves and statistical information we do this by systematically studying integral and variational representations of these objects and in so doing identify their representation primitives which all are related to cost sensitive binary classification as well as developing relationships between generative and discriminative views of learning the new machinery leads to tight and more general surrogate regret bounds and generalised pinsker inequalities relating f divergences to variational divergence the new viewpoint also illuminates existing algorithms it provides a new derivation of support vector machines in terms of divergences and relates maximum mean discrepancy to fisher linear discriminants

jump conditions for strings and sheets from an action principle abstract i present conditions for compatibility of velocities conservation of mass and balance of momentum and energy across moving discontinuities in inextensible strings and sheets of uniform mass density the balances are derived from an action with a time dependent non material boundary and reduce to matching of material boundary conditions if the discontinuity is stationary with respect to the body i first consider a point discontinuity in a string and a line discontinuity in a sheet in the context of classical inertial motion in three euclidean dimensions i briefly comment on line discontinuities terminating in point discontinuities in a sheet discontinuous line discontinuities in a sheet and an approach to dynamic fracture that treats a crack tip in a sheet as a time dependent boundary point i provide two examples of general solutions for conservative sheet motions near a line discontinuity the approach also enables treatment of actions depending on higher derivatives of position i thus derive balances for an elastica which are applicable to moving contact problems

on wave reflections and energetics for a semi infinite traveling string with a nonclassical boundary support abstract the free linear transverse vibrations of a semi infinite axially moving string are considered in order to study the reflection of an incident wave and the damping properties of different types of boundary conditions such as free fixed spring dashpot and mass spring dashpot to obtain the response to the initial conditions the method of d alembert is applied furthermore analytical expressions for the time rate of change of the total mechanical energy of the system are derived the obtained results give insight into the most efficient way of placing a boundary support depending on the direction of the transport velocity moreover for nonclassical boundary conditions the dynamics of the string is described by the relative values of the system parameters

critical crossover phenomena in disordered ising systems the author has investigated the critical behaviour of site disordered ising systems over a large range of dilution 0 6 or p or 1 0 investing about 1015 single spin flips with conventional local dynamics critical temperatures have been determined with high precision using the cumulant method the finite size simulations lead to concentration dependent exponents which seem to violate universality the author shows that the concentration dependence is induced by a crossover phenomenon which governs a large interval of the critical region the author finds that the scaling functions of systems with different disorder converge asymptotically to universal behaviour consistent with the fixed point of weak disorder

crossover effects in dilute magnetic materials by finite time dynamics method abstract crossover phenomena are ubiquitous in disordered system however the crossover effects from the competition between different fixed points make it hard to identify the asymptotic scaling regime controlled by the random fixed point therefore the analyses on the crossover effects are of great importance to understand phase transition in dilute magnetic materials in this paper we derive the scaling function characterizing the crossovers to probe critical behavior according to these we show an alternative method to locate the asymptotic critical region in the quenched random systems in the finite time dynamics frame for the three dimensional bond diluted ising model the asymptotic critical exponents are identified with 0 686 1 0 356 6 0 057 3 1 345 20 z 2 170 11 at middle bond concentration p 0 7 from the effective ones describing the approach to the asymptotic regime for weak dilution p 0 9 and strong dilution p 0 5 the dynamic critical exponent from our non equilibrium simulation supports distinctly z 2 18 as suggested previously as opposed to the existing larger values

effective analysis of damage spreading in ising models using large lattices and different methods of simulation and analysis the kinetic critical exponent z for damage spreading is shown to be consistent with z 2 in two to five dimensions without the logarithmic problems seen in some earlier work

non universality in the dynamics at the percolation threshold the dynamical behavior of the two dimensional ising model at the site percolation threshold on l l lattices with l or 64 is studied by monte carlo simulations the results are consistent with the recently proposed singular dynamic scaling the new dynamical exponents are estimated to be as 0 62 or 0 12 and bs 3 92 or 0 89 comparison with bond dilution strongly suggests that universality is violated for this model

transverse vibrations of elastically connected double string complex system part i free vibrations this paper analyzes the forced transverse vibrations of an elastically connected double string complex continuous system the general solutions of forced vibrations of strings subjected to arbitrarily distributed continuous loads are found by using the method of expansion in a series of the mode shape functions different cases of exciting loadings are analyzed the action of stationary harmonic loads and moving concentrated forces is considered vibrations caused by the harmonic exciting forces are discussed and conditions of resonance and dynamic vibration absorption are formulated thus the string type dynamic absorber can be used to suppress the excessive vibrations of corresponding string systems the dynamic string type damper is a new concept of a continuous dynamic vibration absorber cdva it is shown that a corresponding two degree of freedom discrete system is an analogue of an elastically connected double string complex system theoretical analysis is illustrated by a numerical example

on the crossover to universal criticality in dilute ising systems monte carlo simulations of the critical behaviour of disordered ising systems have led to concentration dependent critical exponents which seem to violate universality we apply the renormalization group to investigate the crossover effects which cause the observed behaviour we improve the three loop expansion of the callan symanzik and wilson functions by a pade borel approximation and solve the flow equations for various initial points the exponents found in the simulations can be related to regions in the space of coupling coefficients away from the fixed point

a symmetric information divergence measure of the csiszar s f divergence class and its bounds a symmetric measure of information divergence is proposed this measure belongs to the class of csiszar s f divergences its properties are studied and bounds in terms of well known divergence measures obtained a numerical illustration is carried out to compare this measure with some known divergence measures

new parametric measures of information in this paper methods are presented for obtaining parametric measures of information from the non parametric ones and from information matrices the properties of these measures are examined the one dimensional parametric measures which are derived from the non parametric are superior to fisher s information measure because they are free from regularity conditions but if we impose the regularity conditions of the fisherian theory of information these measures become linear functions of fisher s measure

technical communique boundary control of the axially moving kirchhoff string in this note the axially moving kirchhoff string is considered it is proved that this non linear string can be stabilized by the linear boundary control which is the negative feedback of the transversal velocity of the string at one end furthermore it is concluded that the axially moving kirchhoff string is stable without an active control when one of its ends is free to move transversally

a reflected wave superposition method for vibration and energy of a travelling string this paper considers the analytical free time domain response and energy in an axially translating and laterally vibrating string the domain of the string is either a constant or variable length dependent upon the general initial conditions the translating tensioned strings possess either fixed fixed or fixed free boundaries an alternative analytical solution using a reflected wave superposition method is presented for a finite translating string firstly the cycles of vibration for both constant and variable length strings are provided which for the latter are dependent upon the variable string length each cycle is divided into three time intervals according to the magnitude and the direction of the translating string velocity applying d alembert s method combined with the reflection properties expressions for the reflected waves at the two boundaries are obtained subsequently superposition of all of the incident and reflected waves provides results for the free vibration of the string over the three time intervals the variation in the total mechanical energy of the string system is also shown the accuracy and efficiency of the proposed method are confirmed numerically by comparison to simulations produced using a newmark beta method solution and an existing state space function representation of the string dynamics

dynamical finite size scaling function of the four dimensional ising model for creutz algorithm abstract dynamical critical exponents for the four dimensional ising model are computed on a cellular automaton from the relaxations of the time displaced correlation for the order parameter and the internal energy at the critical temperatures the analysis of the data within the frame of the dynamical finite size scaling hypothesis gives the linear dynamical critical exponents for the order parameter and the internal energy in our calculation the linear dynamical critical exponents are found z m z h i 2 04 at t c z m 1 99 z h i 2 00 at t c l the values of z m z h i 2 04 obtained for t c verify the dynamical finite size scaling for which it was adopted four dimensional ising model

wave propagation in and vibration of a travelling beam with and without non linear effects part i free vibration the relation between the wave propagation and the free vibration in a travelling beam with simple supports has been thoroughly investigated the frequency equation of such a beam has been derived using the phase closure principle since the characters of the waves change drastically as the axial speed is increased beyond a certain value the phase closure principle has been applied differently in these two speed regimes the justifications for some approximate methods of obtaining the natural frequencies are also discussed lastly the non linear normal modes are derived again using the phase closure principle the computation of the forced response using the wave propagation approach is discussed in part ii

on the refinement of jensen s inequality the main purpose of this work is to present the extension of the recent results given by dragomir s s dragomir a new refinement of jensen s inequality in linear spaces with applications math comput model 52 2010 1497 1505 where new refinement of jensen s inequality is presented and given applications in the information theory our work improves the basic result of dragomir through a stronger refinement of jensen s inequality which is then applied to the information theory and obtained stronger lower bounds for the mean f deviation and f divergences

critical exponents of the dilute ising model from four loop expansions four loop expansions of the coefficients of the callan symanzik equation for 3d and 2d dilute ising models are calculated fixed point coordinates and critical exponents are estimated by two methods of summation of double series a generalisation of the pade borel approximation and the first confluent form of the e algorithm of wynn summation of the double series for the 2d dilute ising model gives exponents very close to exponents of the pure ising model in accordance with the exact solution

new monte carlo method for the self avoiding walk we introduce a new monte carlo algorithm for the self avoiding walk saw and show that it is particularly efficient in the critical region long chains we also introduce new and more efficient statistical techniques we employ these methods to extract numerical estimates for the critical parameters of the saw on the square lattice we find 2 63820 0 00004 0 00030 1 352 0 006 0 025 v 0 7590 0 0062 0 0042 where the first error bar represents systematic error due to corrections to scaling subjective 95 confidence limits and the second bar represents statistical error classical 95 confidence limits these results are based on saws of average length 166 using 340 hours cpu time on a cdc cyber 170 730 we compare our results to previous work and indicate some directions for future research

a generalized treatment of the energetics of translating continua part i strings and second order tensioned pipes the energetics of translating one dimensional uniform strings and highly tensioned pipes with vanishing bending stiffness and flowing fluid are analyzed for fixed free and damped boundary conditions the interaction between the translating continua and the boundary supports causes energy transfer at a fixed boundary the transverse component of tension does work and the coriolis forces at a free end cause energy flux into the second order continuum under a symmetric boundary configuration the total energy of free oscillation varies periodically at the fundamental natural frequency asymmetric boundary supports in the pipe fluid system lead to damped or self excited motions at a viscously damped boundary the condition for maximal energy dissipation the destabilizing effect of dissipation and the stabilizing effect of negative damping are examined analytically using travelling wave solutions the energies transferred at the different boundary supports are quantified by energy reflection coefficients which are determined completely by the boundary conditions numerical simulations verify the analytically predicted energy variations

critical dynamics of cluster algorithms in the dilute ising model autocorrelation times for thermodynamic quantities att c are calculated from monte carlo simulations of the site diluted simple cubic ising model using the swendsen wang and wolff cluster algorithms our results show that for these algorithms the autocorrelation timesdecrease when reducing the concentration of magnetic sites from 100 down to 40 this is of crucial importance when estimating static properties of the model since the variances of these estimators increase with autocorrelation time the dynamical critical exponents are calculated for both algorithms observing pronounced finite size effects in the energy autocorrelation data for the algorithm of wolff we conclude that when applied to the dilute ising model cluster algorithms become even more effective than local algorithms for whichincreasing autocorrelation times are expected

critical dynamics a field theoretical approach we review the progress made in dynamic bulk critical behaviour in equilibrium in the last 25 years since the review of halperin and hohenberg we unify the presentation of the theoretical background by restricting ourselves to the field theoretic renormalization group method the main results obtained in the different universality classes are presented this contains the critical dynamics near the gas liquid transition in pure fluids model h the plait point and consolute point in mixtures model h the superfluid transition in 4 he model f and 4 he 3 he mixtures model f the curie point model j and neel point model g in heisenberg magnets and the superconducting transition in comparison with experimental results it became clear that in most cases one has to consider apart from the universal asymptotic critical behaviour also the non universal effective behaviour either because it turned out to be inevitable due to a small dynamical transient exponent inhibiting the system to reach the asymptotics e g at the superfluid transition or because one is interested in the region further away from the phase transition like in pure fluids and mixtures at their gas liquid or demixing transition the calculation of the critical dynamics is adequate in most cases only in two loop order we review these results and present the solution to unreasonable features found for some models thus we consider model c where relaxational and diffusive dynamics are coupled and the scaling properties and the limit to a purely relaxational model model a have not been understood in general for models where the order parameter couples to other conserved densities time scale ratios between the kinetic coefficients of the order parameter and the conserved densities play an important role their fixed point values and the approach to the fixed point are changed considerably in two loop order compared to their values in one loop order these considerations are relevant for the explanation of the dynamical critical shape functions of systems such as superfluid helium model f and the isotropic antiferromagnet model g as far as possible the comparison of results obtained by the renormalization group theory with numerical simulations has been made

connections of generalized divergence measures with fisher information matrix abstract in this paper parametric measures of information for the multiparameter case are obtained using csiszar s nonparametric measure of information as well as continuous and differentiable functions thereof the same idea is applied to some of the unified r s divergence measures presented in taneja relationships of the new parametric measures with fisher s information matrix are derived and their connections with the cramer rao inequality is established this work generalizes the results of kagan aggarwal and ferentinos and papioannou

the dynamic critical exponent of dilute and pure ising systems a massive dynamic field theory is employed to calculate the critical exponent z of the three dimensional dilute ising model to two loop order without expansion in square root 4 d with result z approximately 2 191 applying the same method to the pure ising model at three loop order we find z 2 022 for d 3 and z 2 124 for d 2

the pivot algorithm a highly efficient monte carlo method for the self avoiding walk the pivot algorithm is a dynamic monte carlo algorithm first invented by lal which generates self avoiding walks saws in a canonical fixed n ensemble with free endpoints heren is the number of steps in the walk we find that the pivot algorithm is extraordinarily efficient one effectively independent sample can be produced in a computer time of ordern this paper is a comprehensive study of the pivot algorithm including a heuristic and numerical analysis of the acceptance fraction and autocorrelation time an exact analysis of the pivot algorithm for ordinary random walk a discussion of data structures and computational complexity a rigorous proof of ergodicity and numerical results on self avoiding walks in two and three dimensions our estimates for critical exponents are 0 7496 0 0007 ind 2 and 0 592 0 003 ind 3 95 confidence limits based on saws of lengths 200 n 10000 and 200 n 3000 respectively

on the convexity of some divergence measures based on entropy functions three measures of divergence between vectors in a convex set of a n dimensional real vector space are defined in terms of certain types of entropy functions and their convexity property is studied among other results a classification of the entropies of degree alpha is obtained by the convexity of these measures these results have applications in information theory and biological studies

ageing properties of critical systems in the past few years systems with slow dynamics have attracted considerable theoretical and experimental interest ageing phenomena are observed during this everlasting non equilibrium evolution a simple instance of such a behaviour is provided by the dynamics that takes place when a system is quenched from its high temperature phase to the critical point the aim of this review is to summarize the various numerical and analytical results that have been recently obtained for this case particular emphasis is put on the field theoretical methods that can be used to provide analytical predictions for the relevant dynamical quantities fluctuation dissipation relations are discussed and in particular the concept of fluctuation dissipation ratio fdr is reviewed emphasizing its connection with the definition of a possible effective temperature the renormalization group approach to critical dynamics is summarized and the scaling forms of the time dependent non equilibrium correlation and response functions of a generic observable are discussed from them the universality of the associated fdr follows as an amplitude ratio it is then possible to provide predictions for ageing quantities in a variety of different models in particular the results for models a b and c dynamics of the o n ginzburg landau hamiltonian and model a dynamics of the weakly dilute ising magnet and of the 3 theory are reviewed and compared with the available numerical results and exact solutions the effect of a planar surface on the ageing behaviour of model a dynamics is also addressed within the mean field approximation

a note on reverse pinsker inequalities a simple method is shown to provide optimal variational bounds on f divergences with possible constraints on relative information extremums the known results are refined or proved to be optimal as particular cases

the energetics and the stability of axially moving kirchhoff strings l the energetics and the stability of free transverse vibration of an axially moving string are investigated based on the kirchhoff nonlinear model the model is derived in a physically meaningful manner the time rate of the total mechanical energy associated with the vibration is calculated to show that the energy is not conserved it is proved that there exists a conserved quantity that remains a constant during the nonlinear vibration the conserved quantity is applied to verify the lyapunov stability of the axially moving kirchhoff string