Newton-Raphson algorithm

This study gives a comparative analysis of the Gauss-Seidel and Newton-Raphson methods for solving the system of linear equations. The methods are executed using Python programming to highlight their computational efficiency and versatility in solving some standard problems. The Gauss-Seidel method, which is an iterative approach ideal for diagonally dominant systems is compared with the Newton-Raphson method, which is known for its rapid convergence in nonlinear systems. Through performance analysis involving convergence rates, computational overheads, and accuracy, the study demonstrates the comparative advantages and limitations of both the methods. Python's abilities, including its autograd module for the evaluation of Jacobian and its built-in libraries for numerical tasks has been used to enhance the implementation efficiency and reproducibility. This work will serve as a resource for the educational purposes and will provide a framework for researchers to model and analyse complex systems of equations.

An extension of the FETI-H method is designed for the solution of acoustic scattering problems with multiple right-hand sides. A new local pre-conditioning of this domain decomposition method is also presented. The potential of the resulting iterative solver is demonstrated by numerical experiments for two-dimensional problems with high wavenumbers, as many as 2:5 million complex degrees of freedom, and a sweep on the angle of the incident wave. Preliminary results for a three-dimensional submarine problem are also included. The FETI-H method, whose numerical scalability with respect to the mesh and subdomain sizes was previously established, is shown here to be also numerically scalable with respect to the wavenumber. Copyright ? 2001 John Wiley & Sons, Ltd.

This paper introduces a shuffled frog-leaping algorithm based method to approximate the equivalent circuit parameters of induction machines from the manufacturer data, such as nameplate data and motor performance characteristics. The steady-state equivalent circuit is applied for the simulations. The circuit parameters are found as the result for the error minimization function between the estimated and maker data. The suggested algorithm solves the parameter estimation problem and surpasses the solutions reached by differential evolution, particle swarm optimization and genetic algorithms. Therefore, this algorithm can be employed in motor energy management system for bettering the overall energy savings in industry.

Leaks are present in all water distribution systems. In this paper a method for leakage detection and localisation is presented. It uses pressure measurements and simulation models. Leakage localisation methodology is based on pressure sensitivity matrix. ...

Transport of contaminants through clays is characterized by a very low dispersivity, but depends on the sensitivity of its intrinsic permeability to the contaminant's concentration. An additional constitutive relationship for a variable intrinsic permeability is thus adopted leading to a coupled system of equations for diffusive–advective transport in multicomponent liquid. A one-dimensional transport problem is solved using finite difference and

We study the problem of parameter estimation for a univariate discretely observed ergodic diffusion process given as a solution to a stochastic differential equation. The estimation procedure we propose consists of two steps. In the first step, which is referred to as a smoothing step, we smooth the data and construct a nonparametric estimator of the invariant density of the process. In the second step, which is referred to as a matching step, we exploit a characterisation of the invariant density as a solution of a certain ordinary differential equation, replace the invariant density in this equation by its nonparametric estimator from the smoothing step in order to arrive at an intuitively appealing criterion function, and next define our estimator of the parameter of interest as a minimiser of this criterion function. Our main results show that under suitable conditions our estimator is √ n-consistent, and even asymptotically normal. We also discuss a way of improving its asymptotic performance through a one-step Newton-Raphson type procedure and present results of a small scale simulation study.

En este trabajo se presenta una variacion del Metodo de Volumenes Finitos (FVM) para la solucion de problemas de valores en la frontera, consistente en la implementacion de un esquema de interpolacion Hermitica utilizando Funciones de Base Radial (RBFs), en lo que se conoce como el metodo CV-RBF (Control Volume- Radial Basis Function). El esquema de interpolacion es una aplicacion local del Metodo Simetrico utilizado en los metodos Sin Malla, en el cual se realiza una aproximacion de la funcion empleando informacion de la ecuacion diferencial parcial (EDP) gobernante y las condiciones de frontera que definen el problema global. Se utiliza la RBF multicuadrica con un parametro de forma hallado experimentalmente. De acuerdo a la naturaleza sin malla del esquema de interpolacion empleado, se llega a una estrategia de discretizacion espacial sumamente versatil en cuanto a geometrias, mallas y condiciones de frontera. El esquema CV-RBF es acoplado con el metodo de Newton-Rapshon y el esqu...

In the case of incomplete data we give general relationships between the first and second derivatives of the loglikelihood relative to the full and the incomplete observation set-ups. In the case where these quantities are easy to compute for the full observation set-up we propose to compute their analogue for the incomplete observation set-up using the above mentioned relationships: this involves numerical integrations. Once we are able to compute these quantities, Newton-Raphson type algorithms can be applied to find the maximum likelihood estimators, together with estimates of their variances. We detail the application of this approach to parametric multiplicative frailty models and we show that the method works well in practice using both a real data and a simulated example. The proposed algorithm outperforms a Newton-Raphson type algorithm using numerical derivatives.

In this paper, we investigate the modeling of ferromagnetic multiscale materials. We propose a computational homogenization method based on the heterogeneous multiscale method (HMM) with inclusion of a hysteresis model. The HMM involves: 1) a macroscale problem that captures the slow variations of the overall solution; 2) many microscale problems that allow to determine the constitutive law at the macroscale. At the microscale, a novel energy consistent hysteresis model is incorporated. As application example, a laminated iron core is considered.

When the long-time behaviour of a concrete dam is analysed, the International Commission of Large Dams recommends to neglect the tensile strength of the dam-foundation joint and to include the uplift pressure due to the water penetrating into the crack. In this context a non-linear problem of contact with friction occurs in the vicinity of the point which separates the damaged part of the joint from the undamaged one. In these conditions the solution depends on the stress path followed during the quasi-static incremental process. Therefore the classical Newton-Raphson fails to converge and has to be replaced by a Large Time Increment method. In this way it was possible to obtain realistic solutions for three different mechanical regimes.

The main objectives of this paper are: 1- Apply the Newton-Raphson technique to determine the pressure value when `h` is set to 0.6. 2- Identify the most favorable relaxation factor for this issue by utilizing an appropriate plot. 3- Organize a table presenting the pressure results for `p` at various `h` values, specifically [0.6, 1.2, 1.8, 2.4, 3, 3.6, 4.2], while considering an appropriate relaxation factor.

The main goal of this work is to examine in detail the equilibrium and non-equilibrium sorption in a multiple species contaminant transport system undergoing multiplicative Monod biodegradation kinetics, which characterizes a scenario of subsurface contamination by organic contaminants. Mathematically, the problem is given by a nonlinear advectiondiffusion-reaction partial differential system coupled by the reaction terms, associated with the biodegradation process. A new operator splitting approach is proposed for treating in a sequential fashion the convective-diffusive and reactive terms. A predictor-multicorrector algorithm with Newton-Raphson and stabilized finite element (streamline-upwind Petrov-Galerkin, SUPG) methods is used in the time and spatial discretizations, respectively. Numerical results illustrate the good applicability of the present approach, corroborating the well-known observation nonlinear physical and biological processes should be inserted in the model that to better predict the contamination scenarios.

We study the problem of parameter estimation for a univariate discretely observed ergodic diffusion process given as a solution to a stochastic differential equation. The estimation procedure we propose consists of two steps. In the first step, which is referred to as a smoothing step, we smooth the data and construct a nonparametric estimator of the invariant density of the process. In the second step, which is referred to as a matching step, we exploit a characterisation of the invariant density as a solution of a certain ordinary differential equation, replace the invariant density in this equation by its nonparametric estimator from the smoothing step in order to arrive at an intuitively appealing criterion function, and next define our estimator of the parameter of interest as a minimiser of this criterion function. Our main results show that under suitable conditions our estimator is √ n-consistent, and even asymptotically normal. We also discuss a way of improving its asymptotic performance through a one-step Newton-Raphson type procedure and present results of a small scale simulation study.

All technologies used the electrical circuits with integrated components based on semiconductor devices such as Diodes, BJTs, MOSFETs…etc,it are nonlinear elements.Before construct any circuit, thesimulation method should be usedto verifying the function of circuit and eliminate of any problem. But there is a problem in the simulation of analog circuitsor complex circuits in particular case.The problem is finding the operating point;this problem dependson the method used by the simulatorto solve nonlinear equations. Thecontinuous method was frequently used in the last ten years; it is an algorithm which deals with the problem of convergence of nonlinear equations using the continuous (homotopy) parameter. It is consists of three stages: the first stage was converts the nonlinear equation to the homotopy equation; the second uses the prediction process to obtain a good approximation of the solution. The last stage based on the correction process which is related on the Newton Raphson...

In this paper, we have introduced a functional approach for approximating nonparametric
functions and coefficients in the presence of multivariate and functional predictors. By utilizing the
Fisher scoring algorithm and the cross-validation technique, we derived the necessary components
that allow us to explain scalar responses, including the functional index, the nonlinear regression operator,
the single-index component, and the systematic component. This approach effectively addresses
the curse of dimensionality and can be applied to the analysis of multivariate and functional random
variables in a separable Hilbert space. We employed an iterative Fisher scoring procedure with
normalized B-splines to estimate the parameters, and both the theoretical and practical evaluations
demonstrated its favorable performance. The results indicate that the nonparametric functions, the
coefficients, and the regression operators can be estimated accurately, and our method exhibits strong
predictive capabilities when applied to real or simulated data.

This paper applies the concept of fuzzy controller to voltage/VAR control. Cascading Mamdani controllers are used together with sensitivities to keep voltages in an admissible band while avoiding line flows to exceed admissible limits. A small number of iteration steps with a Newton-Raphson power flow routine are enough to recover voltages into admissible bands.

Non-isothermal flow through a curved rectangular duct of differentially heated vertical sidewalls is investigated numerically by using the spectral method, and covering a wide range of the Dean number, Dn, ... Keywords: Curved duct, secondary flow, steady solutions, linear stability, ...

Nuclear fusion is nowadays one of the newest and most promising clean energies, composing a new application area of Control Engineering, with new and interesting challenges for the control community. In this sense, this paper deals with the modeling of tokamak nuclear fusion reactors. In order to control the creation of unstable modes in fusion processes, it is necessary to derive numerical models suitable for control strategies. The model presented addresses flux and energy conservation issues, discussing the mechanisms behind the creation of uncontrollable modes. The dynamics of the system is given by means of the energy functions which are solved for the currents in the structure, plasma current and plasma position. Thus, the equations for the state variables are derived based on the Hamiltonian equation of motion. In order to solve numerically, this model is linearised around an operation point by taking a Newton-Raphson step. Besides, the system output is completed by considering the equations for the flux and the poloidal field. Finally, the resulting low-order linear model is modified so as to obtain the corresponding state-space model which is verified by means of numerical simulations.

Plate heat exchangers are gaining acceptance in absorption refrigeration systems due to their high transfer rates, compactness, and low refrigerant charge. Nevertheless, boiling heat transfer and pressure drop studies with mixtures in plate heat exchangers (PHEs) are scarce. In this study, the experimental data of Tá boas et al. (2010) on flow boiling of ammonia/ water in a plate heat exchanger are compared with the predicted values using the correlations available in the open literature for the boiling heat transfer coefficient and pressure drop. In addition, this study proposes a new correlation based on a separate model by which to obtain the boiling coefficient. The new correlation uses a transition criterion, divided into an apparent nucleate boiling region where pure convective boiling cannot appear, and a region with competition between convective and apparent nucleate boiling. The correlation proposed can predict 98% of data from Tá boas et al. (2010) within 20% error.

Recent developments in compact object astrophysics, especially the discovery of merging neutron stars by LIGO, the imaging of the black hole in M87 by the Event Horizon Telescope (EHT) and high precision astrometry of the Galactic Center at close to the event horizon scale by the GRAVITY experiment motivate the development of numerical source models that solve the equations of general relativistic magnetohydrodynamics (GRMHD). Here we compare GRMHD solutions for the evolution of a magnetized accretion flow where turbulence is promoted by the magnetorotational instability from a set of nine GRMHD codes: Athena++, BHAC, Cosmos++, ECHO, H-AMR, iharm3D, HARM-Noble, IllinoisGRMHD and KORAL. Agreement between the codes improves as resolution increases, as measured by a consistently applied, specially developed set of code performance metrics. We conclude that the community of GRMHD codes is mature, capable, and consistent on these test problems.

During the last decades, a family of assumed-strain solid−shell finite elements has been developed with enriched benefits of solid and shell finite elements together with special treatments to avoid locking phenomena. These elements have been shown to be efficient in numerical simulation of thin 3D structures with various constitutive models. The current contribution consists in the combination of the developed linear and quadratic solid−shell elements with complex anisotropic plasticity models for aluminum alloys. Conventional quadratic anisotropic yield functions are associated with less accuracy in the simulation of forming processes with metallic materials involving strong anisotropy. For these materials, the plastic anisotropy can be modeled more accurately using advanced non-quadratic yield functions, such as the anisotropic yield criteria proposed by Barlat for aluminum alloys. In this work, various quadratic and non-quadratic anisotropic yield functions are combined with a linear eight-node hexahedral solid−shell element and a linear six-node prismatic solid−shell element, and their quadratic counterparts. The resulting solid−shell elements are implemented into the ABAQUS software for the simulation of benchmark deep drawing process of a cylindrical cup. The predicted results are assessed and compared to experimental ones taken from the literature. Compared to the use of conventional quadratic anisotropic yield functions, the results given by the combination of the developed solid−shell elements with non-quadratic anisotropic yield functions show good agreement with experiments.

With new systems capable of making synchronized phasor measurements there are possibilities for real-time assessment of the stability of a transient swing in power systems. In the future, on-line control will be necessary as operating points are pushed closer toward the margin and fast reaction time becomes critical to the survival of the system. In this paper we develop a novel class of fuzzy hyperrectangular composite neural networks which utilize real-time phasor angle measurements to provide fast transient stability prediction for use with high-speed control. From simulation tests on a sample power system, it reveals that the proposed tool can yield a highly successful prediction rate in real-time.

To understand, evaluate, and quantify physical and oceanic processes involved in the erosion, deposition, and transport of sediments. This involves short-term and long-term effects, and characterization of those effects based on sediment source and fluid mechanics. The outcome of this work will be a deeper understanding of the processes involved, and further development of predictive capabilities. OBJECTIVE Understanding the mechanics of microventing is of paramount importance to identify the sediment properties and flow threshold conditions that trigger the formation of fluid vents in the subsurface of young (recently deposited) sediments, and for developing a quantitative model that predicts the onset of venting formation and propagation and their effects on settling of suspending aggregates. Knowledge of channel formation can be used to elucidate the mechanisms involved in the stability of young sediments. Such information will be useful to scientists and engineers in several disciplines, including those focusing on the prediction of fate and transport of contaminated sediments and those focusing on the refinement of existing remediation techniques in riverine and estuarine systems (Papanicolaou and Maxwell, 2002). The overall scope of this investigation is to describe the

Non-isothermal flow through a curved rectangular duct of differentially heated vertical sidewalls is investigated numerically by using the spectral method, and covering a wide range of the Dean number, Dn, ... Keywords: Curved duct, secondary flow, steady solutions, linear stability, ...

A wide electricity supply-demand gap especially in developing economy such as Nigeria has created series of challenges such as frequent power outages, poor voltage profile and high power losses among others yet to be addressed. This work examines the effect of Static Var Compensator (SVC), a Flexible Alternating Current Transmission Systems (FACTS) device for performance improvement of power system networks with the Nigerian 330 kV, 28-bus electricity grid considered as a test network. The steady state performance of the system was modeled using Newton-Raphson load flow equations and was simulated without and with compensation on MATLAB/PSAT toolbox (version 2.1.9 'R2012a'). The obtained results showed that the system voltage profile improved to acceptable limit defined as. ≤ ≤. .. with compensation compared to when voltage magnitudes of buses 9, 13, 14, 15, 16, 19, 22 and 26 of the test network fell outside of the acceptable limit without compensation. Also, the system total active power loss reduced from 15.727 MW without SVC to 14.709 MW with SVC, giving a 6.47% reduction in total active power loss. These results showed that the inclusion of SVC on the Nigerian electricity grid will improve both voltage profile and power transfer capability of the system.

In power systems, the mismatch between electricity supply and demand has led to difficulty in maintaining the system voltages within the statutory limit, causing voltage stability problem and consequently poor power transfer. This work is an application of Static Var Compensator (SVC) for voltage stability enhancement and power loss reduction in power system networks using the standard IEEE 6, 14, and 30-bus power networks as case studies. Using MATLAB/PSAT software (version 2.1.9 'R2012a'), the Newton-Raphson power flow modeling the steady state conditions of the sample networks was simulated without and with SVC. The simulation results revealed that the voltage profiles of all the considered networks were enhanced and within acceptable limit of. ≤ ≤. .. after compensation was applied. The system total real power losses of the considered IEEE 6, 14 and 30-bus power networks which were 7.88, 25.76 and 16.05 MW respectively without SVC reduced to 7.08, 24.42 and 15.88 MW respectively with SVC, giving 10.15, 5.20 and 1.06% reduction in total real real power loss respectively for the sample networks. These results showed that SVC as a compensating device is capable of enhancing voltage profile and reducing power loss if incorporated in power system networks.

This article deals with forward kinematics (FK) mapping of a parallel robot, especially designed for ankle joint rehabilitation treatments. Parallel robots exhibit highly coupled non-linear motions hence conventionally a unique closed form solution of their FK cannot be obtained. However, since FK is a key module in closed loop position and force control, its accurate and fast solution is indispensable. To solve the FK problem, a modified fuzzy inference system (FIS) is proposed in this paper for the first time which is time efficient and becomes very accurate when its parameters are optimized. In the proposed work, FIS has been optimized using three approaches namely: gradient descent (GD), genetic algorithm (GA) and modified genetic algorithm (MGA). The FIS, optimized by MGA has been found to be more accurate than the GD and GA optimized FIS. Performance of the MGA based fuzzy system has been found better both in terms of accuracy and computation time, when compared with Newton-Raphson iterative method and other fuzzy and neural approaches.

Linear and non-linear bending analysis of laminated plates with different boundary conditions is presented using generalized differential quadrature (GDQ) method. Governing equations are based on the first-order shear deformation theory (FSDT) and von Kármán-type of geometric non-linearity. GDQ technique and Newton-Raphson method are employed to solve the system of non-linear equations.

In this paper two hybrids of two algorithms, the Newton method and the Gradient Descent method, are presented in order to create polynomiographs. The first idea combines two methods as a convex combination, the second one as the two-step process. A polynomiograph is an image obtained as the result of roots finding method of a polynomial on a complex plain. In this paper the polynomiographs are also modified by using Mann and Ishikawa iterations instead of the standard Picard iteration. Coloring images by iterations reveals dynamic behavior of the used root-finding process and its speed of convergence. The paper joins, combines and modifies earlier results obtained by Kalantari, Zhang et al. and the authors. We believe that the results of the paper can inspire those who are interested in aesthetic patterns created automatically. They can also be used to increase functionality of the existing polynomiography software.

There are two main aims of this paper. The first one is to show some improvement of the robust Newton’s method (RNM) introduced recently by Kalantari. The RNM is a generalisation of the well-known Newton’s root finding method. Since the base method is undefined at critical points, the RNM allows working also at such points. In this paper, we improve the RNM method by applying the Mann iteration instead of the standard Picard iteration. This leads to an essential decrease in the number of root finding steps without visible destroying the sharp boundaries among the basins of attractions presented in polynomiographs. Furthermore, we investigate visually the dynamics of the RNM with the Mann iteration together with the basins of attraction for varying Mann’s iteration parameter with the help of polynomiographs for several polynomials. The second aim of this paper is to present the intriguing polynomiographs obtained from the dynamics of the RNM with the Mann iteration under various sequ...

The aim of this paper is to investigate experimentally and to present visually the dynamics of the processes in which in the standard Newton’s root-finding method the classic derivative is replaced by the fractional Riemann–Liouville or Caputo derivatives. These processes applied to polynomials on the complex plane produce images showing basins of attractions for polynomial zeros or images representing the number of iterations required to obtain polynomial roots. These latter images were called by Kalantari as polynomiographs. We use both: the colouring by roots to present basins of attractions, and the colouring by iterations that reveal the speed of convergence and dynamic properties of processes visualised by polynomiographs.

In this paper, an iteration process, referred to in short as MMP, will be considered. This iteration is related to finding the maximum modulus of a complex polynomial over a unit disc on the complex plane creating intriguing images. Kalantari calls these images polynomiographs independently from whether they are generated by the root finding or maximum modulus finding process applied to any polynomial. We show that the images can be easily modified using different MMP methods (pseudo-Newton, MMP-Householder, methods from the MMP-Basic, MMP-Parametric Basic or MMP-Euler-Schröder Families of Iterations) with various kinds of non-standard iterations. Such images are interesting from three points of views: scientific, educational and artistic. We present the results of experiments showing automatically generated non-trivial images obtained for different modifications of root finding MMP-methods. The colouring by iteration reveals the dynamic behaviour of the used root finding process and its speed of convergence. The results of the present paper extend Kalantari's recent results in finding the maximum modulus of a complex polynomial based on Newton's process with the Picard iteration to other MMP-processes with various non-standard iterations.

Non-isothermal flow through a curved rectangular duct of differentially heated vertical sidewalls is investigated numerically by using the spectral method, and covering a wide range of the Dean number, Dn, ... Keywords: Curved duct, secondary flow, steady solutions, linear stability, ...

This paper presents a new computer-aided design (CAD) system for automated sizing of analog integrated circuits (ICs). A new evolutionary algorithm, called New Hybrid Shuffled Frog Leaping (NHSFL) Algorithm, is proposed to deal with the equality and inequality constraints in the problem and to deduce the device sizes optimizing the performance of the circuits. For this, a new frog leaping rule is proposed to improve the local exploration and performance of the standard SFLA. Also, to improve the convergence velocity of the algorithm, the mutation operator is used for generating new frog, instead of random mechanism. By linking MATLAB and HSPICE the system evaluates the circuit performance during electrical simulation, in the optimization loop in the MATLAB environment, to be selected as an appropriate circuit topology. To assess the system, complex and hard-to-design analog blocks with restricted design requirements are presented in 0.18 mm CMOS process technology. The simulation results obtained from the proposed system verify that the design requirements are closely satisfied, even in tough conditions. Furthermore, some comparisons are made with available methods like Genetic algorithm (GA) and Imperialist Competitive algorithm (ICA) showing that the presented algorithm offers excellent qualifications in terms of time, efficiency and robustness.

In this paper a novel approach is proposed for constructing discrete counterparts of constitutive equations over polyhedral grids which ensure both consistency and stability of the algebraic equations discretizing an electromagnetic field problem. The idea is to construct discrete constitutive equations preserving the thermodynamic relations for constitutive equations. In this way, consistency and stability of the discrete equations are ensured. At the base, a purely geometric condition between the primal and the dual grids has to be satisfied for a given primal polyhedral grid, by properly choosing the dual grid. Numerical experiments demonstrate that the proposed discrete constitutive equations lead to accurate approximations of the electromagnetic field.

The key to the problem of node coverage in wireless sensor networks (WSN) is to deploy a limited number of sensors to achieve maximum coverage. This paper studies the hybrid strategies of multiple evolutionary algorithms, and applies them to the problem of WSN node coverage. We first proposed the hybrid algorithm SFLA-WOA (SWOA) based on Shuffled Frog Leaping Algorithm (SFLA) and Whale Optimization Algorithm (WOA). The SWOA algorithm combines the advantages of SFLA and WOA; that is, it retains the unique evolution model of WOA and also has the excellent co-evolution capability of SFLA. Secondly, using the mutation, crossover and selection operations of the differential evolution (DE) algorithm to further optimize this hybrid algorithm, the SWOA-based SFLA-WOA-DE (SWOAD) algorithm is proposed. In addition, the performance of SWOA and SWOAD has been tested by 30 benchmark functions in the CEC 2017 test set. Experimental results show that the optimization effects of these two algorithm...

The method of stress-function in elasticity theory is a powerful analytical tool with applications to a wide range of physical systems, including defective crystals, fluctuating membranes, and more. A complex coordinates formulation of stress function, known as Kolosov-Muskhelishvili formalism, enabled the analysis of elastic problems with singular domains, particularly cracks, forming the basis for fracture mechanics. A shortcoming of this method is its limitation to linear elasticity, which assumes Hookean energy and linear strain measure. Under finite loads, the linearized strain fails to describe the deformation field adequately, reflecting the onset of geometric nonlinearity. The latter is common in materials experiencing large rotations, such as regions close to the crack tip or elastic metamaterials. While a nonlinear stress function formalism exists, Kolosov-Muskhelishvili complex representation had not been generalized and remained limited to linear elasticity. This paper develops a Kolosov-Muskhelishvili formalism for nonlinear stress function. The new formalism allows us to port methods from complex analysis to nonlinear elasticity and to solve nonlinear problems in singular domains. Upon implementing the method to the crack problem, we discover that nonlinear solutions strongly depend on the applied remote loads, excluding a universal form of the solution close to the crack tip and questioning the validity of previous studies of nonlinear crack analysis.

This paper introduces a shuffled frog-leaping algorithm based method to approximate the equivalent circuit parameters of induction machines from the manufacturer data, such as nameplate data and motor performance characteristics. The steady-state equivalent circuit is applied for the simulations. The circuit parameters are found as the result for the error minimization function between the estimated and maker data. The suggested algorithm solves the parameter estimation problem and surpasses the solutions reached by differential evolution, particle swarm optimization and genetic algorithms. Therefore, this algorithm can be employed in motor energy management system for bettering the overall energy savings in industry.

Shaping axi-symmetric planetary nebulae is easier if a companion interacts with a primary at the top of the asymptotic giant branch. To determine the impact of binarity on planetary nebula formation and shaping, we need to determine the central star of planetary nebula binary fraction and period distribution. The short-period binary fraction has been known to be 10-15% from a survey of ∼100 central stars for photometric variability indicative of irradiation effects, ellipsoidal variability or eclipses. This survey technique is known to be biased against binaries with long periods and this fact is used to explain why the periods of all the binaries discovered by this survey are smaller than 3 days. In this paper we assess the status of knowledge of binary central stars discovered because of irradiation effects. We determine that, for average parameters, this technique should be biased against periods longer than 1-2 weeks, so it is surprising that no binaries were found with periods longer than 3 days. Even more puzzling is the fact that 9 out of 12 of the irradiated binaries, have periods smaller than one day, a fact that is starkly at odds with post-common envelope predictions. We suggest that either all common envelope models tend to overestimate post-common envelope periods or that this binary survey might have suffered from additional, unquantified biases. If the latter hypothesis is true, the currently-known shortperiod binary fraction is put in serious doubt. We also introduce a new survey for binary-related variability, which will enable us to better quantify biases and determine an independent value for the short period binary fraction.

Prediction of the initiation of ductile fracture in deep drawing allows a prior modification of the process which can result in a defect-free final product. This paper deals with the prediction of fracture initiation in deep drawn cup using Lemaitre's continuum damage mechanics model. The damage is incorporated in the constitutive equation through the principle of strain equivalence. The damage is evaluated using the damage growth law proposed by Lemaitre. An in-house 3D finite element formulation is employed for the analysis. Finite element formulation is based on updated Lagrangian approach. Logarithmic strain measure is used. The incremental stress is made objective by evaluating it in a frame rotating with the material particle. The material is assumed to be elasto-plastic with isotropic strain hardening using von Mises yield criterion. Modified Newton-Raphson iterative technique is used to solve the nonlinear incremental equations. The fracture location predicted by the present formulation is in agreement with the results reported in the literature.

The present study covers a comprehensive numerical study on fully developed two-dimensional flow of viscous incompressible fluid through a curved rectangular duct of aspect ratio 4. Numerical calculations are carried out by using a spectral method, and covering a wide range of the Dean number, , 1000 100   Dn for two cases of the duct curvature, Case I: 001. 0   and Case II: 1. 0  . The main concern of the present study is to find out effects of curvature as well as formation of Dean vortices on unsteady solutions as the unsteady flow is steady-state, periodic, multi-periodic or chaotic, if the Dn is increased. Time evolution calculations show that the steady-state flow turns into chaotic flow through various flow instabilities, if Dn is increased no matter what the curvature is. It is found that the unsteady flow is a steady-state solution for small Dn`s, and it oscillates periodically or non-periodically (chaotic) between two-, four-, six-, eight-ten-and twelve-vortex solutions, if Dn is increased. In this study, we obtained multi-vortex solutions due to strong centrifugal force. It is found that the chaotic solution is weak for small Dn's but strong as Dn becomes large. It is also found that the axial flow shifted to the outer wall of the duct as Dn increases.

Abstract-In this study, an elastic-plastic stress analysis was carried out in woven steel fibers- thermoplastic clamped composite laminates. The stacking sequences were chosen as [0/0] 2 , [15/-15] 2 , [30/-30] 2 and [45/-45] 2 for woven steel fibers – thermoplastic composites plates. The layers were chosen for symmetric and antisymmetric cases. The finite element solution was performed by using the ANSYS software. Solid 186 element was utilized in the solution. Normal stress components at the clamped edges were found to be higher than that at the mid point of the laminated plates. Normal stresses are tensile at the mid point of the clamped edges and compressive at the mid point of the laminated plates. Then, the residual stress components were calculated in the critical points of the composite laminates. Keywords-elastic-plastic stress analysis, thermoplastic composite laminates, finite element method 1. I TRODUCTIO Thermoplastic composites gain some advantages in nowadays. Since i...

In the present study an elastic-plastic stress analysis is carried out for long silicon carbide fiber reinforced magnesium metal matrix composite with a square hole by using finite element technique. Composite material is manufactured by using molds under a pressure of 35 MPa and heating up to 550 0 C by electrical resistance. The laminated plates with square hole consist of four layers and bonded symmetrically. Each layer with constant thickness is meshed into 48 elements and 228 nodes with simply supported. The expansion of plastic zone and residual stress are determined in the symmetric cross-ply and angle-ply laminated plates for small deformations. The load is increased by 0.01 MPa at each step. Iteration numbers are chosen as 150, 300 and 600. The resılts show that the intensity of the residual stresses is maximum near the open square hole and the yield points in symmetric laminates are higher than those in antisymmetric laminates.The plastic regions at the plate edges expand in the direction of the fiber, but at the border of the hole expand toward the diagonal of the hole.

In this study, an elastic-plastic stress analysis was carried out in woven steel fibers-thermoplastic clamped composite laminates. The stacking sequences were chosen as [0/0] 2 , [15/-15] 2 , [30/-30] 2 and [45/-45] 2 for woven steel fibersthermoplastic composites plates. The layers were chosen for symmetric and antisymmetric cases. The finite element solution was performed by using the ANSYS software. Solid 186 element was utilized in the solution. Normal stress components at the clamped edges were found to be higher than that at the mid point of the laminated plates. Normal stresses are tensile at the mid point of the clamped edges and compressive at the mid point of the laminated plates. Then, the residual stress components were calculated in the critical points of the composite laminates.

Esse estudo conta com uma boa introdução sobre a família de distribuições exponenciais que é um tema indispensável quando se fala em Modelos Lineares Generalizados e também um bom conteúdo sobre estes últimos. Foram utilizadas as funções de ligação logit e probit com o intuito de avaliar o desempenho das mesmas na estimação de parâmetros com dados alterados. Fixaram-se três valores diferentes para o parâmetro beta, que é uma probabilidade de sucesso, em seguida, foram realizadas 1000 simulações (estimações) para cada combinação dos parâmetro e das funções de ligação. Foi utilizado o Erro Quadrático Médio e a porcentagem de erros quadráticos menores que 0,02 para serem utilizados para comparação. Chegou-se a conclusão de que a função de ligação probit foi a mais indicada para estimar os parâmetros com valores próximos a zero e que a função de ligação logit foi a mais indicada para a estimação de parâmetros com valores próximos a um. Todo o procedimento foi realizado através do software livre R.

In this work, we present a per-instant pose optimization method that can generate configurations that achieve specified pose or motion objectives as best as possible over a sequence of solutions, while also simultaneously avoiding collisions with static or dynamic obstacles in the environment. We cast our method as a multi-objective, non-linear constrained optimization-based IK problem where each term in the objective function encodes a particular pose objective. We demonstrate how to effectively incorporate environment collision avoidance as a single term in this multi-objective, optimization-based IK structure, and provide solutions for how to spatially represent and organize external environments such that data can be efficiently passed to a real-time, performancecritical optimization loop. We demonstrate the effectiveness of our method by comparing it to various state-of-the-art methods in a testbed of simulation experiments and discuss the implications of our work based on our results.

In recent years, distributed generations (DGs) are extremely fast in detecting their location, which helps to satisfy the ever-increasing power demands. The placement of energy storage systems (ESSs) could be a substantial opportunity to enhance the presentation of radial distribution system (RDS). The major part of DG units in RDS deals with the detection of ideal placement and size of the DGs, which efficiently balance the power loss and voltage stability. The ideal location and size of ESSs are examined in standard IEEE-33 and 69 bus systems, which is important to reduce power losses. Nowadays, several algorithms or techniques are modified for the development of hybrid algorithms to improve the quality of DG allocation. In this research, a hybrid shuffled frog leap algorithm (SFLA) with ant lion optimizer (SFLA-ALO) is proposed for the optimal placement and size of the DG and ESS in the RDS to reduce power losses and maintain the stability of voltage. The performance of the propo...