nonlocal problems involving spatial structure for coupled reaction diffusion systems the purpose of this work is to investigate the uniqueness and existence of solutions for a system of nonlinear parabolic equations weakly coupled with ordinary differential equations in bounded domains subject to nonlocal boundary conditions that involve values of the unknown functions inside of the spatial domain the solutions of such problems allow for considering not only physical chemical or biological properties but also spatial structure of the modelled system the uniqueness of classical solutions of the nonlocal boundary problems for coupled reaction diffusion systems is proved by means of comparison principles for differential inequalities the existence of the unique solution is obtained via a monotone iterative method applications are given to some model problems in epidemiology and ecology with the nonlocal boundary conditions based on the inverse distance weighting interpolation and cokriging

the generalized quasi linearization method for reaction diffusion equations on an unbounded domain the method of generalized quasi linearization has been well developed for ordinary differential equations in this paper we extend the method of generalized quasi linearization to reaction diffusion equations on an unbounded domain the iterates which are solutions of linear equations starting from lower and upper solutions converge uniformly and monotonically to the unique solution of the nonlinear reaction diffusion equation in an unbounded domain initially an existence theorem for the linear nonhomogeneous reaction diffusion equation in an unbounded domain has been proved under improved conditions the quadratic convergence has been proved by using a comparison theorem of reaction diffusion equations with ordinary differential equations this avoids the computational complexity of the quasi linearization method since the computation of green s function at each stage of the iterates is avoided

the variational principle and fixed point theorems in certain topological spaces abstract the main purpose of this paper is to introduce the concept off type topological spaces and to establish a variational principle and a fixed point theorem in the kind of spaces which extend ekeland s variational principle and caristi s fixed point theorem respectively

local completeness drop theorem and ekeland s variational principle by using a very general drop theorem in locally convex spaces we obtain some extended versions of ekeland s variational principle which only need assume local completeness of some related sets and improve hamel s recent results from this we derive some new versions of caristi s fixed points theorems in the framework of locally convex spaces we prove that danes drop theorem ekeland s variational principle caristi s fixed points theorem and phelps lemma are equivalent to each other

an extension of ekeland s variational principle to locally complete spaces we prove an extension of ekeland s variational principle to locally complete spaces which uses subadditive strictly increasing continuous functions as perturbations

multi objective robust pid controller tuning using two lbests multi objective particle swarm optimization in this paper two lbests multi objective particle swarm optimization 2lb mopso is applied to design multi objective robust proportional integral derivative pid controllers for two mimo systems namely distillation column plant and longitudinal control system of the super maneuverable f18 harv fighter aircraft multi objective robust pid controller design problem is formulated by minimizing integral squared error ise and balanced robust performance criteria during the search 2lb mopso can focus on small regions in the parameter space in the vicinity of the best existing fronts as the lbests are chosen from the top fronts in a non domination sorted external archive of reasonably large size the offspring obtained can be more diverse with good fitness the performance of various optimal pid controllers is compared in terms of the sum of ise and balanced robust performance criteria for the purpose of comparison 2lb mopso nsga ii as well as earlier reported riccati iga and osa methods are considered the performance of pid controllers obtained using 2lb mopso is better than that of others in addition hypervolume based comparisons are carried out to show the superior performance of 2lb mopso over nsga ii the results reveal that 2lb mopso yields better robustness and consistency in terms of the sum of ise and balanced robust performance criteria than various optimal pid controllers

reaction diffusion systems with time delays monotonicity invariance comparison and convergence in a recent paper we have obtained differential inequality results developed comparison theorems and established invariance criteria for mild solutions of abstract functional differential equations in a banach space the primary application for these results is to reaction diffusion systems in which the reaction nonlinearity contains time delays in the present paper we apply these results to reaction diffusion systems with time delays of the form u t d u f x u t x x u u n 0 x where is a bounded open set in r n with smooth boundary u r n d diag d 1 d n with d i 0

parabolic systems in unbounded domains i existence and dynamics abstract in this paper we investigate the existence uniqueness and asymptotic behavior of a solution for a class of coupled nonlinear parabolic equations in a general unbounded domain that includes the whole space r n the exterior of a bounded domain and a half space in r n the asymptotic behavior of the solution is with respect to a pair of quasi solutions of the corresponding elliptic system and when these two quasi solutions coincide the solution of the parabolic system converges to a unique solution of the elliptic system

firefly algorithm approach based on chaotic tinkerbell map applied to multivariable pid controller tuning nowadays a variety of controllers used in process industries are still of the proportional integral derivative pid types pid controllers have the advantage of simple structure good stability and high reliability a relevant issue for pid controllers design is the accurate and efficient tuning of parameters in this context several approaches have been reported in the literature for tuning the parameters of pid controllers using evolutionary algorithms mainly for single input single output systems the systematic design of multi loop or decentralized pid control for multivariable processes to meet certain objectives simultaneously is still a challenging task this paper proposes a new chaotic firefly algorithm approach based on tinkerbell map cfa to tune multi loop pid multivariable controllers the firefly algorithm is a metaheuristic algorithm based on the idealized behavior of the flashing characteristics of fireflies to validate the performance of the proposed pid control design a multi loop multivariable pid structure for a binary distillation column plant wood and berry column model and an industrial scale polymerization reactor are taken simulation results indicate that a suitable set of pid parameters can be calculated by the proposed cfa besides some comparison results of a genetic algorithm a particle swarm optimization approach traditional firefly algorithm modified firefly algorithm and the proposed cfa to tune multi loop pid controllers are presented and discussed

coupled nonlinear parabolic systems with time delays a coupled system of parabolic equations with time delays is investigated by the method of upper lower solutions it is shown by using upper and lower solutions as coupled initial iterations that the corresponding sequences converge monotonically to a unique solution of the system this convergence leads to an existence comparison theorem which is useful for studying the asymptotic behavior of the solution this method is extended to a coupled system of integro differential equations and systems of parabolic ordinary equations applications are given to some model problems in ecology and nuclear engineering including the stability property of a steady state solution

stability of abstract nonlinear nonautonomous differential delay equations with unbounded history responsive operators we consider a class of nonautonomous functional differential equations in a banach space with unbounded nonlinear history responsive operators which have the local lipshitz property conditions for the boundedness of solutions lyapunov stability absolute stability and input output one are established our approach is based on a combined usage of properties of sectorial operators and spectral properties of commuting operators

dynamics of nonlinear parabolic systems with time delays abstract the dynamics of a coupled system of semilinear parabolic equations with discrete time delays is investigated using the method of upper and lower solutions it is shown that if the reaction function in the system possesses a mixed quasimonotone property and the corresponding elliptic system has a pair of coupled upper and lower solutions then there is a monotone iteration process which yields a pair of quasisolutions of the elliptic system and the sector between the quasisolutions is an attractor of the delayed parabolic system under some additional conditions this sector is a global attractor and the solution of the parabolic system converges to a true solution of the elliptic system the same conclusions are obtained for a coupled system of parabolic ordinary equations with time delays applications are given to three model problems arising from ecology and nuclear engineering these model problems possess multiple steady state solutions and sufficient conditions are given to ensure the stability and instability of these solutions

on positive solutions of the lotka volterra cooperating models with diffusion abstract in this paper using the existence and comparison conclusion for the time periodic quasimonotone nondecreasing systems given by pao c v and iterative method we investigate the time periodic lotka volterra cooperating model and present some existence uniqueness and nonexistence results we also use similar methods to treat the corresponding stationary system to give parallel results

self organizing genetic algorithm based tuning of pid controllers this paper proposes a self organizing genetic algorithm soga with good global search properties and a high convergence speed first we introduce a new dominant selection operator that enhances the action of the dominant individuals along with a cyclical mutation operator that periodically varies the mutation probability in accordance with evolution generation found in biological evolutionary processes next the soga is constructed using the two operators mentioned above the results of a nonlinear regression analysis demonstrate that the self organizing genetic algorithm is able to avoid premature convergence with a higher convergence speed and also indicate that it possesses self organization properties finally the new algorithm is used to optimize proportional integral derivative pid controller parameters our simulation results indicate that a suitable set of pid parameters can be calculated by the proposed soga

local completeness and pareto optimization in this paper we study the pareto optimization problem in the framework of locally convex spaces with the restricted assumption that only some related sets are locally complete

solution estimates for abstract nonlinear time variant differential delay equations abstract semilinear time variant functional differential equations in a banach space are considered a solution estimate is derived by that estimate explicit conditions for boundedness of solutions and stability are established

parabolic systems in unbounded domains ii equations with time delays abstract this paper extends the results of an earlier article concerning the existence uniqueness comparison and dynamics problems for a coupled system of parabolic equations in unbounded domains including the whole space r n the present extension is for a system of functional parabolic ordinary equations where the reaction function is allowed to depend on the unknown function with time delay which may be discrete or continuous finite or infinite applications are made to some model problems with emphasis on the convergence fo the time dependent solution to a steady state solution and the decay property of the solution as x

iterative two step genetic algorithm based method for efficient polynomial b spline surface reconstruction surface reconstruction is a very challenging problem arising in a wide variety of applications such as cad design data visualization virtual reality medical imaging computer animation reverse engineering and so on given partial information about an unknown surface its goal is to construct to the extent possible a compact representation of the surface model in most cases available information about the surface consists of a dense set of either organized or scattered 3d data points obtained by using scanner devices a today s prevalent technology in many reverse engineering applications in such a case surface reconstruction consists of two main stages 1 surface parameterization and 2 surface fitting both tasks are critical in order to recover surface geometry and topology and to obtain a proper fitting to data points they are also pretty troublesome leading to a high dimensional nonlinear optimization problem in this context present paper introduces a new method for surface reconstruction from clouds of noisy 3d data points our method applies the genetic algorithm paradigm iteratively to fit a given cloud of data points by using strictly polynomial b spline surfaces genetic algorithms are applied in two steps the first one determines the parametric values of data points the later computes surface knot vectors then the fitting surface is calculated by least squares through either svd singular value decomposition or lu methods the method yields very accurate results even for surfaces with singularities concavities complicated shapes or nonzero genus six examples including open semi closed and closed surfaces with singular points illustrate the good performance of our approach our experiments show that our proposal outperforms all previous approaches in terms of accuracy and flexibility

an intelligent noise reduction method for chaotic signals based on genetic algorithms and lifting wavelet transforms time series observed in real world is often nonlinear even chaotic however observed data is often contaminated by noise of various types to effectively extract desired information from observed data it is vital to preprocess data to reduce noise for both the analysis of dynamical systems and many potential applications of these systems in this paper we present a noise reduction approach to the problem of additive source separation characterized by wide band power spectra when one of the sources is chaotic the algorithm is based on a center based genetic algorithm cbga in lifting wavelet framework in which the cbga is used for threshold optimization this method intelligently adapts itself to various types of noise and it weighs preservation of dynamics and denoising through signal to noise ratio snr and root mean square error rmse computer simulations show that the approach is very effective in diminishing different kinds of noise and performs better in terms of visual quality as well as quantitative metrics than existing algorithms

systems of parabolic equations with continuous and discrete delays abstract in this paper we investigate the global existence and the dynamics of a coupled system of nonlinear parabolic equations where the nonlinear reaction function may depend on both continuous infinite or finite and discrete delays it is shown that if the reaction function is locally lipschitz continuous and the system possesses a pair of coupled upper and lower solutions then there exists a unique global solution to the system without any quasimonotone condition on the reaction function for systems with mixed quasimonotone reaction functions we use the monotone method to establish more dynamic property of the parabolic system in terms of the quasisolutions of the corresponding elliptic system this approach yields a global attractor of the parabolic system and under some additional conditions this attractor leads to the existence and asymptotic stability of a solution of the elliptic system application to three model problems in population dynamics and chemical reactions is given