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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - A Novel Coding Phase Gradient Metasurface for Wideband RCS Reduction
摘要： In this letter, a new design of metasurface based on coding phase gradient metasurface for wideband radar cross section (RCS) reduction is proposed. The unit cell of the metasurface is composed of a Jerusalem structure and a central circular ring. In order to reduce the burden of the computation time and to optimize design procedure, we use the genetic algorithm and nonlinear fitting method to determine the unit cell geometer. By changing and selecting the parameter of each unit, it is found that the reflection phase of the unit can achieve a stable distribution of phase gradient of the cell among the frequency range of 7.5–26 GHz. In our design, both the random coding sequences and gradient phases in the coding elements are combined to manipulate the EM waves. Four kinds of super-cells with different gradient directions are obtained according to the generalized Snell’s Law, serving as the coding element. A coding metasurface composed of 6 × 6 supercells with random arrangement is designed to improve its RCS reduction. By coding four types of linear-phase gradients in a random pattern, reflected wave can be uniformly diffused. Moreover, the manipulation of waves will be more flexible compared with other designs. The simulated results show that a 10 dB RCS reduction is realized over broadband ranging from 7.5 to 26 GHz.
关键词： nonlinear fitting,coding phase gradient,metasurface,genetic algorithm,RCS reduction
更新于2025-09-19 17:13:59
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A calibration method of dual two-dimensional laser range finders for mobile manipulator
摘要： In this article, a method for calibrating the relative position between dual two-dimensional laser range finders is proposed. This relative position is affected by the manufacture or assembling error of mobile platform, and this error could reduce the accuracy of localization. This article focuses on three-degree-of-freedom calibration, that is, one rotational and two translational degrees of freedom. The entire calibration process can be summed up into three steps. The first step is to allow the dual finders to scan one corner at the same time and then extract the parameters of the corner. The second step is to establish a cost function which is established according to the direction vector of the line and the repeatability of the corners. With this function, the genetic algorithm is used to obtain the final calibration result. Moreover, the finder systematic error and the statistical error are also considered into this article. Simulations and experiments are carried out to verify the proposed method.
关键词： 2-D laser range finder,genetic algorithm,Calibration,mobile manipulator
更新于2025-09-19 17:13:59
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Corrections to a??Highly Conductive and Broadband Transparent Zr-Doped In <sub/>2</sub> O <sub/>3</sub> as Front Electrode for Solar Cellsa?? [Sep 18 1202-1207]
摘要： An intelligent hybrid Taguchi-genetic algorithm (IHTGA) is used to optimize bearing offsets and shaft alignment in a marine vessel propulsion system. The objectives are to minimize normal shaft stress and shear force. The constraints are permissible reaction force, bearing stress, shear force, and bending moment in the shaft thrust ?ange under cold and hot operating conditions. Accurate alignment of the shaft for a main propulsion system is important for ensuring the safe operation of a vessel. To obtain a set of acceptable forces and stresses for the bearings and shaft under operating conditions, the optimal bearing offsets must be determined. Instead of the time-consuming classical local search methods with some trial-and-error procedures used in most shipyards to optimize bearing offsets, this paper used IHTGA. The proposed IHTGA performs Taguchi method between the crossover operation of the conventional GA. Incorporating the systematic reasoning ability of Taguchi method in the crossover operation enables intelligent selection of genes used to achieve crossover, which enhances the performance of the IHTGA in terms of robustness, statistical performance, and convergence speed. A penalty function method is performed using the ?tness function as a pseudo-objective function comprising a linear combination of design objectives and constraints. A ?nite-element method is also used to determine the reaction forces and stresses in the bearings and to determine normal stresses, bending moments, and shear forces in the shaft. Computational experiments in a 2200 TEU container vessel show that the results obtained by the proposed IHTGA are signi?cantly better than those obtained by the conventional local search methods with some trial-and-error procedures.
关键词： genetic algorithm,shaft alignment,Marine vessel propulsion system,bearing offsets,optimal design
更新于2025-09-19 17:13:59
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[IEEE 2019 Chinese Automation Congress (CAC) - Hangzhou, China (2019.11.22-2019.11.24)] 2019 Chinese Automation Congress (CAC) - Research on Reactive Power Optimization Control Strategy of Distribution Network with Photovoltaic Generation
摘要： What the thesis studies is the active and reactive decoupling control method of photovoltaic grid-connected inverter, and then the reactive power of grid-connected inverter is optimized by genetic algorithm with the objective of minimizing network loss, So as to realize reactive power optimization control of the photovoltaic power generation system.An algorithm based on genetic algorithm for reactive power optimization of photovoltaic power generation and distribution network is proposed.A mathematical model for reactive power optimization of distribution network has been established. The mathematical model those of photovoltaic power generation system Considering the limits of not only minimum network loss but also node voltage, what is used to optimize the reactive power of photovoltaic power generation is genetic algorithm. The example simulation results indicate the designed optimization algorithm is effective and correct in reducing power loss and improving voltage quality.
关键词： Photovoltaic power generation,Grid-connected inverter,Genetic algorithm,Reactive power optimization
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Architecture, Construction, Environment and Hydraulics (ICACEH) - Xiamen, China (2019.12.20-2019.12.22)] 2019 IEEE International Conference on Architecture, Construction, Environment and Hydraulics (ICACEH) - Optimal Decision of Photovoltaic Generation Injection Point in Unbalanced Distribution System
摘要： In this paper, the photovoltaic generation was considered as the only one renewable power source to supply system load of a chemical factory directly. An improved genetic algorithm was applied to determine the optimal location and capacity of newly constructed PV generation systems by considering system loss minimization and improving voltage unbalance through simulation with solar power injected.
关键词： Optimal Feed-in Location,Renewable Energy,Photovoltaic Generation,Genetic Algorithm
更新于2025-09-19 17:13:59
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Shaping of a laser-accelerated proton beam for radiobiology applications via genetic algorithm
摘要： Laser-accelerated protons have a great potential for innovative experiments in radiation biology due to the sub-picosecond pulse duration and high dose rate achievable. However, the broad angular divergence makes them not optimal for applications with stringent requirements on dose homogeneity and total flux at the irradiated target. The strategy otherwise adopted to increase the homogeneity is to increase the distance between the source and the irradiation plane or to spread the beam with flat scattering systems or through the transport system itself. Such methods considerably reduce the proton flux and are not optimal for laser-accelerated protons. In this paper we demonstrate the use of a Genetic Algorithm (GA) to design an optimal non-flat scattering system to shape the beam and efficiently flatten the transversal dose distribution at the irradiated target. The system is placed in the magnetic transport system to take advantage of the presence of chromatic focusing elements to further mix the proton trajectories. The effect of a flat scattering system placed after the transport system is also presented for comparison. The general structure of the GA and its application to the shaping of a laser-accelerated proton beam are presented, as well as its application to the optimisation of dose distribution in a water target in air.
关键词： Genetic algorithm,Beam shaping,Laser-driven protons,Monte Carlo simulations,Dose optimisation
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Genetically Optimized Photonic Crystal for Spatial Filtering of Reinjection into Broad-Area Diode Lasers
摘要： Modern high-power broad-area semiconductor laser diodes (BASLDs) deliver optical output powers of several ten Watts at high electro-optical conversion efficiencies, which makes them highly relevant for numerous industrial, medical and scientific applications. However, lateral multimode behavior in BASLDs due to thermal lensing turns out highly detrimental, as it results in poor focusability and decreased laser beam brightness. Approaches to overcome this issue include improved epitaxial layer design, the optimization of evanescent spatial filtering by tailoring the emitter geometry and facet reflectivity, or Fourier spatially filtered reinjection from an external resonator. Here, we consider the usage of longitudinally chirped photonic crystals (PhC) within the external cavity (EC) for tailoring the spatial filter properties. The corresponding EC setup, consisting of a slow-axis collimating lense, a 2D photonic crystal, and the external mirror (R=4%), is shown in Fig. 1a). While free space propagation in the EC is modeled by Fresnel diffraction integrals, optical propagation through the PhC requires accurate treatment of lateral angular dispersion. For the sake of efficiency of the time-domain BASLD simulator, we use a beam propagation method (BPM) based on Rayleigh-Sommerfeld diffraction theory. The chirp of the longitudinal PhC periods is optimized with a genetic algorithm. The transmission amplitude of the optimized structure suppresses lateral propagation angles between 2° and 4°, cf. Fig. 1b), and shows excellent agreement with an exact rigorous coupled wave analysis (RCWA) for calculating PhC transmission and almost vanishing reflection amplitudes. In a next step, we performed numerical simulations of a 1mm long and 100μm broad BASLD subject to PhC spatially filtered reinjection. We found a significant improvement of the lateral far-field profile and increase of beam brightness by a factor 1.5, cf. Fig. 1c). However, for BASLDs with a longer emitter length, lateral waveguide dispersion considerably limits the effectiveness of our scheme. In summary, we demonstrated theoretically that spatial filtering with photonic crystals is a viable alternative to Fourier slit spatial filtering schemes, and offers increased flexibility for designing tailored angular transmission profiles by suitably optimized longitudinal PhC chirp.
关键词： genetic algorithm,beam propagation method,photonic crystals,spatial filtering,broad-area semiconductor laser diodes
更新于2025-09-16 10:30:52
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Improving laser cutting quality of polymethylmethacrylate sheet: experimental investigation and optimization
摘要： Motivated by the need to enhance the kerf quality during cutting of Poly(methyl methacrylate) (PMMA) sheets using pulsed CO2 laser beam, this study presents an experimental investigation and optimization of laser cutting parameters including cutting speed, assisted gas pressure, laser beam power, and sheet thickness. The kerf quality characteristics including the top kerf width, bottom kerf width, and kerf taper have been considered as the process responses and have been measured using polarized light microscope. The experiments were designed and planned using Taguchi L18 orthogonal array with a mixed design. The effects of different cutting parameters on the kerf characteristics have been statistically analyzed using analysis of variance technique (ANOVA). The obtained results revealed that any increase in cutting parameters will result in increasing the top and the bottom kerf widths, while increasing cutting speed or laser power results in increasing the kerf taper. Second order regression models have been developed to model different kerf characteristics as functions of the process parameters. Genetic algorithm (GA) has been used to select the optimal cutting parameters using the developed regression model as an objective function to minimize the kerf taper. A considerable improvement in kerf quality has been achieved and the obtained results have been verified using confirmation experiments. The application of the proposed approach is capable to reduce the kerf taper from 1.92? to 0.02? while maintaining the minimum kerf width at a reasonable value (less than 0.5 mm).
关键词： Genetic algorithm,PMMA,Regression analysis,Taguchi method,Laser cutting,kerf geometry
更新于2025-09-16 10:30:52
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Investigation of optimal process parameters for laser cutting of Inconel-718 sheet
摘要： Precise machining of advance material like Inconel-718 is an emerging need. Selection of an appropriate optimal range of cutting parameters is quite essential to achieve the high-quality cut and is a challenging task within this domain of study. The aim of this research is to develop a robust prediction model, which can suggest the desired range of cutting parameters for accomplishing better cutting quality, precision, and geometrical accuracy. Experiments have been performed on a 300 W (CNC-PCT 300) pulsed Nd: YAG laser cutting system at various levels of input cutting parameters, namely gas pressure, standoff distance, cutting speed, and laser power. Thereafter, response surface methodology has been adopted to develop mathematical models in terms of aforementioned input cutting parameters for geometrical quality characteristics: top kerf width and bottom kerf width. These developed models have been validated by comparing the predicted values with the experimental ones. Further, these models have been optimized using the multiobjective genetic algorithm in order to ascertain the optimal range of cutting parameters pertaining to better quality cut with high precision and geometrical accuracy.
关键词： laser cutting,response surface method,Inconel-718,genetic algorithm
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Capacity Expansion based Network Failure Recovery with Genetic Algorithm
摘要： To overcome the network bottleneck when a failure occurs, a capacity expansion based recovery model is established, and is solved by genetic algorithm under link recovery and path recovery strategies, achieving the minimal network expansion cost.
关键词： Fault Recovery,Genetic Algorithm,Network Capacity Expansion,IP + optical
更新于2025-09-16 10:30:52