In order to slove the large-scale nonlinear programming （NLP） problems efficiently, an efficient optimization algorithm based on reduced sequential quadratic programming （rSQP） and automatic differentiation （AD）...
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In order to slove the large-scale nonlinear programming （NLP） problems efficiently, an efficient optimization algorithm based on reduced sequential quadratic programming （rSQP） and automatic differentiation （AD） is presented in this paper. With the characteristics of sparseness, relatively low degrees of freedom and equality constraints utilized, the nonlinear programming problem is solved by improved rSQP solver. In the solving process, AD technology is used to obtain accurate gradient information. The numerical results show that the combined algorithm, which is suitable for large-scale process optimization problems, can calculate more efficiently than rSQP itself.
In artificial immune optimization algorithm, the mutation of immune cells has been considered as the key operator that determines the algorithm performance. Traditional immune optimization algorithms have used a singl...
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In artificial immune optimization algorithm, the mutation of immune cells has been considered as the key operator that determines the algorithm performance. Traditional immune optimization algorithms have used a single mutation operator, typically a Gaussian. Using a variety of mutation operators that can be combined during evolution to generate different probability density function could hold the potential for producing better solutions with less computational effort. In view of this, a linear combination mutation operator of Gaussian and Cauchy mutation is presented in this paper, and a novel clonal selection optimization method based on clonal selection principle is proposed also. The simulation results show the combining mutation strategy can obtain the same performance as the best of pure strategies or even better in some cases.
A nondestructive evaluation technique established on the basis of a global minimization method is presented for the system parameters identification of flexibly supported rectangular laminated composite sandwich plate...
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A nondestructive evaluation technique established on the basis of a global minimization method is presented for the system parameters identification of flexibly supported rectangular laminated composite sandwich plates using measured natural frequencies of the sandwich plates. In this study, the first eight natural frequencies extracted from impulsive vibration testing data are used to identify the system parameters of the flexibly supported sandwich plates. In the identification process, the trial system parameters are used in the Rayleigh-Ritz method to predict the theoretical natural frequencies of the sandwich plate, a frequency discrepancy function is established to measure the sum of the squared differences between the experimental and theoretical predictions of the natural frequencies, and the global minimization method is used to search for the best estimates of the system parameters by making the frequency discrepancy function a global minimum. The accuracy and efficiency of the proposed technique in identifying the system parameters of several flexibly supported sandwich plates made of different face and core materials are studied via both theoretical and experimental approaches. The reasonably good results obtained in this study have demonstrated the applicability of the proposed technique.
This paper proposes a new methodology for the automatic characterization of the influent wastewater in WWTP. With this methodology, model components are automatically estimated by means of optimization algorithms comb...
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ISBN:
(纸本)1843391481
This paper proposes a new methodology for the automatic characterization of the influent wastewater in WWTP. With this methodology, model components are automatically estimated by means of optimization algorithms combining a-priori knowledge of the expected wastewater composition with experimental information from the available measurement data. The characterization is carried out based on an extended model components list in which components are described by means their elemental mass fractions. This allows an easy establishment of relationships between model components with experimental data and also, to obtain a general methodology applicable to any model used for wastewater biological treatments. The characterization of the wastewater influent of Galindo-Bilbao according this methodology has demonstrated its validity and the easy application to the ASM1 model influent characterization.
An important source of uncertainty in finite element models used for static and fatigue analysis is due to inaccuracy in estimating both the magnitude and distribution of loads. Furthermore, it is often assumed in the...
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An important source of uncertainty in finite element models used for static and fatigue analysis is due to inaccuracy in estimating both the magnitude and distribution of loads. Furthermore, it is often assumed in the models that the structure is rigidly supported even though there may be significant compliance at the support. It is often difficult to accurately estimate the compliance as well as the actual distribution of the load. Recent improvements in experimental techniques enable full-field strain measurement with relative ease for structural components. A method for using these measurements to compute the applied load and distribution, as well as compliances at the supported boundaries, is presented in this paper. Accurately determining the loads and boundary conditions can significantly improve the ability to predict fatigue life and the likely location of failure for structures.
A novel approach for optical beam distribution into two-dimensional (2D) fibre arrays using 2D Dammann gratings is investigated. We report for the first time experimental results of a 2D optical power distribution int...
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A novel approach for optical beam distribution into two-dimensional (2D) fibre arrays using 2D Dammann gratings is investigated. We report for the first time experimental results of a 2D optical power distribution into 2 x 2 polymer optical fibre arrays using a Dammann grating. This paper focuses on the design and fabrication of the diffractive optical element (DOE) along with investigating the coupling performance of the system. This grating may be applicable to a fibre to the home (FTTH) network as it can support sufficient channels with good output uniformity together with low polarization-dependent loss (PDL). Using an appropriate optimization algorithm, the optimum profile for the Dammann gratings can be calculated. The gratings are then fabricated on indium-doped tin oxide (ITO) glass using electron-beam lithography. This method shows that it can achieve low PDL and good uniformity together with acceptable insertion loss.
We report the use of adaptive optics with coherent anti-Stokes Raman scattering (CARS) microscopy for label-free deep tissue imaging based on molecular vibrational spectroscopy. The setup employs a deformable membrane...
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We report the use of adaptive optics with coherent anti-Stokes Raman scattering (CARS) microscopy for label-free deep tissue imaging based on molecular vibrational spectroscopy. The setup employs a deformable membrane mirror and a random search optimization algorithm to improve signal intensity and image quality at large sample depths. We demonstrate the ability to correct for both system and sample-induced aberrations in test samples as well as in muscle tissue in order to enhance the CARS signal. The combined system and sample- induced aberration correction increased the signal by an average factor of similar to 3x for the test samples at a depth of 700 mu m and similar to 6x for muscle tissue at a depth of 260 mu m. The enhanced signal and higher penetration depth offered by adaptive optics will augment CARS microscopy as an in vivo and in situ biomedical imaging modality. (c) 2007 Optical Society of America.
Heat transfer from hot aluminium walls to cold water sprays was investigated. The method used was the transient two-side symmetric cooling of a planar aluminium target, previously heated to temperatures of up to 750 K...
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Heat transfer from hot aluminium walls to cold water sprays was investigated. The method used was the transient two-side symmetric cooling of a planar aluminium target, previously heated to temperatures of up to 750 K, by twin sprays issuing from full-cone swirl spray nozzles of various gauge. The target's mid-plane temperature was recorded during the cooling transient by thin-foil K thermocouples and a high-frequency data acquisition system. In order to determine the wall temperature T-w, the wall heat flux q(w)" and the q(w)" - T-w heat W W transfer (Nukiyama) curve, two different approaches were used: the first was based on the solution of an inverse heat conduction problem, the second on a suitable parameterization of the Nukiyama curve and on the solution of a minimum problem. Relevant heat transfer quantities, such as the critical heat flux and the single-phase heat transfer coefficient, were obtained from each heat transfer curve. Their dependence on the main parameters characterizing the spray impact phenomenon (mass flow rate, drop velocity and drop diameter) was investigated on the basis of a preliminary hydrodynamic characterization study, and suitable correlations were proposed. (c) 2007 Elsevier Ltd. All rights reserved.
Multimode fibers are characterized by multipath propagation of optical signals and this leads to severe intersymbol interference at the output of the fiber. In this work an approach based on the Rake receiver is propo...
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Multimode fibers are characterized by multipath propagation of optical signals and this leads to severe intersymbol interference at the output of the fiber. In this work an approach based on the Rake receiver is proposed to overcome this drawback. An optimization algorithm was developed and appropriate software was employed to apply the proposed methodology on specific multimode fiber. Extensive simulation results were produced and are presented herein. The numerical results have shown that the order of magnitude of the maximum data rate, R, supported at different CDMA gains, in order to achieve a Bit Error Rate value smaller or equal to a convergent point, is related to the length of the multimode fiber, L, by the expression R = dL(-1) with d increasing from 10(6) to 10(7) (Kbps m) when CDMA gain increases from 50 to 500.
We consider a trader who wants to direct his or her portfolio towards a set of acceptable wealths given by a convex risk measure. We propose a Monte Carlo algorithm, whose inputs are the joint law of stock prices and ...
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We consider a trader who wants to direct his or her portfolio towards a set of acceptable wealths given by a convex risk measure. We propose a Monte Carlo algorithm, whose inputs are the joint law of stock prices and the convex risk measure, and whose outputs are the numerical values of initial capital requirement and the functional form of a trading strategy for achieving acceptability. We also prove optimality of the capital obtained. Explicit theoretical evaluations of hedging strategies are extremely difficult, and we avoid the problem by resorting to such computational methods. The main idea is to utilize the finite Vapnik-Cervonenkis dimension of a class of possible strategies. (C) 2007 Elsevier B.V. All rights reserved.
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