Journal articles: 'Methods of three-dimensional optimization'

1

Brune, Alexander, and Michal Kočvara. "On Barrier and Modified Barrier Multigrid Methods for Three-Dimensional Topology Optimization." SIAM Journal on Scientific Computing 42, no. 1 (January 2020): A28—A53. http://dx.doi.org/10.1137/19m1254490.

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Rebai, Maher, Matthieu le Berre, Faicel Hnaien, and Hichem Snoussi. "Exact Biobjective Optimization Methods for Camera Coverage Problem in Three-Dimensional Areas." IEEE Sensors Journal 16, no. 9 (May 2016): 3323–31. http://dx.doi.org/10.1109/jsen.2016.2519451.

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Shang, Kun, and Kai Zhang. "Three-Dimensional Sonar Imaging Software on the DSP." Advanced Materials Research 219-220 (March 2011): 49–52. http://dx.doi.org/10.4028/www.scientific.net/amr.219-220.49.

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This paper has explored the design of three-dimensional imaging sonar software and its application to the hardware platform. In the process of designing, the software has been optimized in view of characteristics of the hardware structures and calculation of the TMS320C6416, and the specific optimization methods and effects have also been presented. It turns out that the effect of software optimization is obvious and the working system stable and reliable.

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Simonetti, Hélio Luiz, Valério Silva Almeida, Francisco de Assis das Neves, Vírgil Del Duca Almeida, and Luttgardes de Oliveira Neto. "Reliability-Based Topology Optimization: An Extension of the SESO and SERA Methods for Three-Dimensional Structures." Applied Sciences 12, no. 9 (April 22, 2022): 4220. http://dx.doi.org/10.3390/app12094220.

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This study takes an approach to reliability-based topology optimization (RBTO) for 3D structures by applying an expansion of smoothing evolutionary structural optimization (SESO) and sequential element rejection and admission (SERA) for three-dimensional optimization. In the search for the stable optimal solution, and a more reliable structure, we present a performance index with the ability to monitor the evolutionary optimization procedure and adopt the filtering scheme usually applied in solid isotropic material with penalization (SIMP). The limit state functions are the maximum displacement constraints imposed in the topology optimization procedure and a structure’s performance control; a comparative analysis of the deterministic topology optimization (DTO) with the RBTO models is also explored. The obtained results suggest the importance of using the RBTO concept in 3D structures as part of the design analysis process.

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Zangeneh, M., A. Goto, and H. Harada. "On the role of three-dimensional inverse design methods in turbomachinery shape optimization." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 1 (January 1, 1999): 27–42. http://dx.doi.org/10.1243/0954406991522167.

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The application of a three-dimensional (3D) inverse design method in which the blade geometry is computed for a specified distribution of circulation to the design of turbomachinery blades is explored by using two examples. In the first instance the method is applied to the design of radial and mixed flow impellers to suppress secondary flows. Based on our understanding of the fluid dynamics of the flow in the impeller, simple guidelines are developed for input specification of the inverse method in order to systematically design impellers with suppressed secondary flows and a more uniform exit flow field. In the second example the method is applied to the design of a vaned diffuser. Again based on the understanding of the detailed flow field in the diffuser obtained by using 3D viscous calculations and oil flow visualizations, simple design guidelines are developed for input specification to the inverse method in order to suppress corner separation. In both cases the guidelines are verified numerically and in the case of the diffuser further experimental validation is presented.

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Chen, L. L., H. Lian, Z. Liu, H. B. Chen, E. Atroshchenko, and S. P. A. Bordas. "Structural shape optimization of three dimensional acoustic problems with isogeometric boundary element methods." Computer Methods in Applied Mechanics and Engineering 355 (October 2019): 926–51. http://dx.doi.org/10.1016/j.cma.2019.06.012.

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von den Hoff, Bieke, Roberto Merino-Martínez, Dick G. Simons, and Mirjam Snellen. "Using global optimization methods for three-dimensional localization and quantification of incoherent acoustic sources." JASA Express Letters 2, no. 5 (May 2022): 054802. http://dx.doi.org/10.1121/10.0010456.

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Complex acoustic systems typically present three-dimensional distributions of noise sources. Conventional acoustic imaging methods with planar microphone arrays are unsuitable for three-dimensional acoustic imaging, given the computational demands and the incapability to explicitly account for the presence of multiple sources. This paper proposes the use of global optimization methods to solve these shortcomings. An experiment with three incoherent speakers proved that this method can accurately determine the three-dimensional location and the respective sound level of each individual source. In addition, super-resolution is achieved beyond half the Rayleigh resolution limit.

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TAKAHASHI, Toko, Takahiro FUJIKAWA, and Koichi YONEMOTO. "Investigations of Shape Definition and Aerodynamics Analysis Methods for Three-Dimensional Aerodynamic Shape Optimization." Proceedings of Conference of Kyushu Branch 2019.72 (2019): C21. http://dx.doi.org/10.1299/jsmekyushu.2019.72.c21.

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Schoen, Fabio. "Global optimization methods for high-dimensional problems." European Journal of Operational Research 119, no. 2 (December 1999): 345–52. http://dx.doi.org/10.1016/s0377-2217(99)00136-8.

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Xiao, Yanyang, Zhonggui Chen, Zhengtao Lin, Juan Cao, Yongjie Jessica Zhang, Yangbin Lin, and Cheng Wang. "Merge-Swap Optimization Framework for Supervoxel Generation from Three-Dimensional Point Clouds." Remote Sensing 12, no. 3 (February 2, 2020): 473. http://dx.doi.org/10.3390/rs12030473.

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Surpervoxels are becoming increasingly popular in many point cloud processing applications. However, few methods have been devised specifically for generating compact supervoxels from unstructured three-dimensional (3D) point clouds. In this study, we aimed to generate high quality over-segmentation of point clouds. We propose a merge-swap optimization framework that solves any supervoxel generation problem formulated in energy minimization. In particular, we tailored an energy function that explicitly encourages regular and compact supervoxels with adaptive size control considering local geometric information of point clouds. We also provide two acceleration techniques to reduce the computational overhead. The performance of the proposed merge-swap optimization approach is superior to that of previous work in terms of thorough optimization, computational efficiency, and practical applicability to incorporating control of other properties of supervoxels. The experiments show that our approach produces supervoxels with better segmentation quality than two state-of-the-art methods on three public datasets.

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Wang, Tongke. "Alternating Direction Finite Volume Element Methods for Three-Dimensional Parabolic Equations." Numerical Mathematics: Theory, Methods and Applications 3, no. 4 (June 2010): 499–522. http://dx.doi.org/10.4208/nmtma.2010.m99027.

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Li, Linfeng, and Xiao-Jing Jia. "Three-Dimensional Reconstruction of Cerebrovascular and Algorithm Realization." Journal of Healthcare Engineering 2021 (November 24, 2021): 1–7. http://dx.doi.org/10.1155/2021/7422884.

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Objective. In the three-dimensional reconstruction of CT cerebrovascular medical image registration, a new optimization algorithm based on the relative position information between the contours of various blood vessels in the image is proposed. Methods. Using the rule that the center of gravity of the vascular tissue structure on the series of slices has continuity, find the registration relationship between the contours of the vessels in the two adjacent slices. Because the shape of cerebrovascular contour is relatively symmetrical, its center of gravity is slightly away from its geometric center. Therefore, the geometric center is used to replace the center of gravity, and the “mass” of each contour is calculated according to the area of each contour to achieve the registration of the blood vessel contour. Results. The method has the characteristics of global optimization and stronger robustness. Conclusion. The cerebrovascular image obtained by this method is more realistic and can be used for the import of various software, simulation training, and later research, which provides an effective method for preoperative simulation of cerebrovascular intervention surgery.

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Lou, Xiao Ping, Nai Guang Lv, Peng Sun, and Yi Min Lin. "Data Registration Method Based on Three Dimensional Target." Applied Mechanics and Materials 103 (September 2011): 87–91. http://dx.doi.org/10.4028/www.scientific.net/amm.103.87.

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Data registration method using special three dimensional target to track the structured light measurement system is discussed. Optical scanning device, tracking target and stereo vision system are integrated together to fulfill profile inspection of large-scale free-form surface objects without extra mark points. System architecture and processing steps are introduced and layout optimization methods of three dimensional target are illustrated. Experimental results are showed to evaluate the validity of the registration method and suggests are given to improve the accuracy of the system.

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Wolosz, Krzysztof J., and Jacek Wernik. "Three-Dimensional Flow Optimization of a Nozzle with a Continuous Adjoint." International Journal of Nonlinear Sciences and Numerical Simulation 16, no. 3-4 (June 1, 2015): 151–56. http://dx.doi.org/10.1515/ijnsns-2014-0011.

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AbstractThe article presents results of multi-criteria optimization of air nozzle topology. The optimization in the CFD has been recently developed since equations of flow in porous media were applied among others governing equations. Optimization is a seeking for extremum of an objective function with respect to the function constraints. With this definition in mind, the optimization by using a continuous adjoint for the current cases is a finding such channel topology which minimizes for example pressure or energy loss when the constraints of objective function are in the form of flow governing equations of momentum and continuity. This methodology of optimization makes a design process faster comparing to the methods related to Design of Experiments (DoE). However, for the sake of flow governing equations nonlinearity, the continuous adjoint method can be successfully applied only in relatively simply and steady-state cases. The reason is of possibility of finding the global extremum of the objective function only for that kind of cases. The results of optimization of two selected cases are presented in the article and show advantages and limitations of the method applied. The continuous adjoint simulation results indicate the nozzles design directions and can be applied in industry with limited reliability. The object of research reported in the article is the nozzle which is augmented equipment used with a pneumatic pulsator. The pulsators are devices that utilize an air stream to destruct vaults created in loose material structure. The pulsator productivity equipped with a nozzle depends on outlet pressure. Therefore, the optimization problem was stated so that pressure loss is to be as low as possible.

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Lv, Jia Liang, Ying Long Wang, Huan Qing Cui, and Nuo Wei. "Weight Selection and PSO Based Three-Dimensional Localization for Wireless Sensor Networks." Applied Mechanics and Materials 427-429 (September 2013): 2540–44. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.2540.

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Localization is one of the key technologies of wireless sensor networks, and the problem of localization is always formulated as an optimization problem. Particle swarm optimization (PSO) is easy to implement and requires moderate computing resources, which is feasible for localization of sensor networks. To improve the efficiency and precision of PSO-based localization methods, this paper proposes a novel three-dimensional PSO method based on weight selection (WSPSO). Simulation results show that the proposed method outperforms standard PSO and existing localization algorithms.

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Gulayeva, Nataliya, Volodymyr Shylo, and Mykola Glybovets. "Genetic Algorithms as Computational Methods for Finite-Dimensional Optimization." Cybernetics and Computer Technologies, no. 3 (September 30, 2021): 5–14. http://dx.doi.org/10.34229/2707-451x.21.3.1.

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Introduction. As early as 1744, the great Leonhard Euler noted that nothing at all took place in the universe in which some rule of maximum or minimum did not appear [12]. Great many today’s scientific and engineering problems faced by humankind are of optimization nature. There exist many different methods developed to solve optimization problems, the number of these methods is estimated to be in the hundreds and continues to grow. A number of approaches to classify optimization methods based on various criteria (e.g. the type of optimization strategy or the type of solution obtained) are proposed, narrower classifications of methods solving specific types of optimization problems (e.g. combinatorial optimization problems or nonlinear programming problems) are also in use. Total number of known optimization method classes amounts to several hundreds. At the same time, methods falling into classes far from each other may often have many common properties and can be reduced to each other by rethinking certain characteristics. In view of the above, the pressing task of the modern science is to develop a general approach to classify optimization methods based on the disclosure of the involved search strategy basic principles, and to systematize existing optimization methods. The purpose is to show that genetic algorithms, usually classified as metaheuristic, population-based, simulation, etc., are inherently the stochastic numerical methods of direct search. Results. Alternative statements of optimization problem are given. An overview of existing classifications of optimization problems and basic methods to solve them is provided. The heart of optimization method classification into symbolic (analytical) and numerical ones is described. It is shown that a genetic algorithm scheme can be represented as a scheme of numerical method of direct search. A method to reduce a given optimization problem to a problem solvable by a genetic algorithm is described, and the class of problems that can be solved by genetic algorithms is outlined. Conclusions. Taking into account the existence of a great number of methods solving optimization problems and approaches to classify them it is necessary to work out a unified approach for optimization method classification and systematization. Reducing the class of genetic algorithms to numerical methods of direct search is the first step in this direction. Keywords: mathematical programming problem, unconstrained optimization problem, constrained optimization problem, multimodal optimization problem, numerical methods, genetic algorithms, metaheuristic algorithms.

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Outinen, K., H. Vuorela, and R. Hiltunen. "Optimization of HPLC separation by computer-assisted optimization methods. Comparison of three methods." European Journal of Pharmaceutical Sciences 4, no. 4 (June 1996): 199–210. http://dx.doi.org/10.1016/0928-0987(95)00040-2.

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Wang, Zhan Zhong, Jing Fu, Lan Fang Liu, and Rui Rui Liu. "Three Dimensional Offline Packing Optimization Problem Based on Genetic Simulated Annealing Algorithm." Applied Mechanics and Materials 744-746 (March 2015): 1919–23. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1919.

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In this paper, we try to solve 3D offline packing optimization problem by combining two methods-genetic algorithm’ global performance and simulated annealing algorithm’ local performance. Given Heuristic rules in loading conditions, we use the optimal preservation strategy and the roulette wheel method to choose selection operator, integrating simulated annealing algorithm into genetic algorithm , and achieving code programming and algorithms by Matlab.This paper carries out an actual loading in a vehicle company in Changchun City, then makes a contrast between the final optimization results and each suppliers’ current packing data.The experimental results show that the algorithm has a certain validity and practicability in multiple container packing problem.

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Pintér, J. "Globally convergent methods for n-dimensional multiextremal optimization." Optimization 17, no. 2 (January 1986): 187–202. http://dx.doi.org/10.1080/02331938608843118.

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BROADIE, MARK, and WEIWEI SHEN. "HIGH-DIMENSIONAL PORTFOLIO OPTIMIZATION WITH TRANSACTION COSTS." International Journal of Theoretical and Applied Finance 19, no. 04 (May 25, 2016): 1650025. http://dx.doi.org/10.1142/s0219024916500254.

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This paper studies Merton’s portfolio optimization problem with proportional transaction costs in a discrete-time finite horizon. Facing short-sale and borrowing constraints, investors have access to a risk-free asset and multiple risky assets whose returns follow a multivariate geometric Brownian motion. Lower and upper bounds for optimal solutions up to the problem with 20 risky assets and 40 investment periods are computed. Three lower bounds are proposed: the value function optimization (VF), the hyper-sphere and the hyper-cube policy parameterizations (HS and HC). VF attacks the conundrums in traditional value function iteration for high-dimensional dynamic programs with continuous decision and state spaces. HS and HC respectively approximate the geometry of the trading policy in the high-dimensional state space by two surfaces. To evaluate lower bounds, two new upper bounds are provided via a duality method based on a new auxiliary problem (OMG and OMG2). Compared with existing methods across various suites of parameters, new methods lucidly show superiority. The three lower bound methods always achieve higher utilities, HS and HC cut run times by a factor of 100, and OMG and OMG2 mostly provide tighter upper bounds. In addition, how the no-trading region characterizing the optimal policy deforms when short-sale and borrowing constraints bind is investigated.

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Gigante, Giacomo, and Christian Vergara. "Optimized Schwarz methods for the coupling of cylindrical geometries along the axial direction." ESAIM: Mathematical Modelling and Numerical Analysis 52, no. 4 (July 2018): 1597–615. http://dx.doi.org/10.1051/m2an/2018039.

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In this work, we focus on the Optimized Schwarz Method for circular flat interfaces and geometric heterogeneous coupling arising when cylindrical geometries are coupled along the axial direction. In the first case, we provide a convergence analysis for the diffusion-reaction problem and jumping coefficients and we apply the general optimization procedure developed in Gigante and Vergara (Numer. Math. 131 (2015) 369–404). In the numerical simulations, we discuss how to choose the range of frequencies in the optimization and the influence of the Finite Element and projection errors on the convergence. In the second case, we consider the coupling between a three-dimensional and a one-dimensional diffusion-reaction problem and we develop a new optimization procedure. The numerical results highlight the suitability of the theoretical findings.

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Lahanas, M., D. Baltas, S. Giannouli, N. Milickovic, and N. Zamboglou. "Generation of uniformly distributed dose points for anatomy-based three-dimensional dose optimization methods in brachytherapy." Medical Physics 27, no. 5 (May 2000): 1034–46. http://dx.doi.org/10.1118/1.598970.

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Ma, Y. Z. "Three-Dimensional Modeling of Mineral/Elemental Compositions for Shale Reservoirs." SPE Journal 25, no. 04 (May 20, 2020): 2067–78. http://dx.doi.org/10.2118/201118-pa.

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Summary Mineral compositional analysis of rocks is important for developing shale resources because the relationships between mineral compositions and petrophysical properties are critical for resource evaluation and completion optimization. Elementary properties are now routinely analyzed at wells in evaluating shale reservoirs. However, these properties have not been modeled in the three-dimensional (3D) reservoir. This is because an elemental composition has a physical constraint that is relatively easily adhered to in data analysis for wells but not in 3D modeling of reservoirs. A critical condition of elemental composition is that the sum of its components is equal to 100% to honor the mass-preservation principle. Traditional modeling methods do not satisfy this physical condition, sometimes producing nonphysical values, such as negative porosity values and fluid-saturation values greater than 100%. To date, only the compositional-modeling methods using a log-ratio transform can consistently satisfy this physical constraint. This paper presents modeling methods using additive log-ratio transform for modeling mineral compositions.

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Zhao, Qinghai, Xiaokai Chen, Zheng-Dong Ma, and Yi Lin. "Robust Topology Optimization Based on Stochastic Collocation Methods under Loading Uncertainties." Mathematical Problems in Engineering 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/580980.

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A robust topology optimization (RTO) approach with consideration of loading uncertainties is developed in this paper. The stochastic collocation method combined with full tensor product grid and Smolyak sparse grid transforms the robust formulation into a weighted multiple loading deterministic problem at the collocation points. The proposed approach is amenable to implementation in existing commercial topology optimization software package and thus feasible to practical engineering problems. Numerical examples of two- and three-dimensional topology optimization problems are provided to demonstrate the proposed RTO approach and its applications. The optimal topologies obtained from deterministic and robust topology optimization designs under tensor product grid and sparse grid with different levels are compared with one another to investigate the pros and cons of optimization algorithm on final topologies, and an extensive Monte Carlo simulation is also performed to verify the proposed approach.

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Wołosz, Krzysztof J., and Jacek Wernik. "ICEEM07: Three-Dimensional Flow Optimization of a Pneumatic Pulsator Nozzle with a Continuous Adjoint." International Journal of Nonlinear Sciences and Numerical Simulation 16, no. 1 (February 1, 2015): 3–9. http://dx.doi.org/10.1515/ijnsns-2014-0043.

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AbstractThe article presents results of multi-criteria optimization of air nozzle topology. The optimization in the Computational Fluid Dynamics (CFD) has been recently developed since equations of flow in porous media were applied among others governing equations. Optimization is a seeking for extremum of an objective function with respect to the function constraints. With this definition in mind, the optimization by using a continuous adjoint for the current cases is a finding such channel topology which minimizes for example pressure or energy loss when the constraints of objective function are in the form of flow governing equations of momentum and continuity. This methodology of optimization makes a design process faster comparing to the methods related to Design of Experiments (DoE). However, for the sake of flow governing equations nonlinearity, the continuous adjoint method can be successfully applied only in relatively simply and steady-state cases. The method consists in seeking of a global extremum of objective function. This extremum can sometimes be find in only simple and stationary events. The results of optimization of two selected cases are presented in the article and show advantages and limitations of the method applied. The continuous adjoint simulation results indicate the nozzles design directions and can be applied in industry with limited reliability. The object of research reported in the article is the nozzle which is augmented equipment used with a pneumatic pulsator. The pulsators are devices that utilize an air stream to destruct vaults created in loose material structure. The pulsator productivity equipped with a nozzle depends on outlet pressure. Therefore, the optimization problem was stated so that pressure loss is to be as low as possible.

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Kalatehjari, Roohollah, Ahmad Safuan A Rashid, Nazri Ali, and Mohsen Hajihassani. "The Contribution of Particle Swarm Optimization to Three-Dimensional Slope Stability Analysis." Scientific World Journal 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/973093.

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Over the last few years, particle swarm optimization (PSO) has been extensively applied in various geotechnical engineering including slope stability analysis. However, this contribution was limited to two-dimensional (2D) slope stability analysis. This paper applied PSO in three-dimensional (3D) slope stability problem to determine the critical slip surface (CSS) of soil slopes. A detailed description of adopted PSO was presented to provide a good basis for more contribution of this technique to the field of 3D slope stability problems. A general rotating ellipsoid shape was introduced as the specific particle for 3D slope stability analysis. A detailed sensitivity analysis was designed and performed to find the optimum values of parameters of PSO. Example problems were used to evaluate the applicability of PSO in determining the CSS of 3D slopes. The first example presented a comparison between the results of PSO and PLAXI-3D finite element software and the second example compared the ability of PSO to determine the CSS of 3D slopes with other optimization methods from the literature. The results demonstrated the efficiency and effectiveness of PSO in determining the CSS of 3D soil slopes.

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Li, Xingxing, Dangwei Wang, and Xiaoyan Ma. "Three-Dimensional Target Localization and Cramér-Rao Bound for Two-Dimensional OFDM-MIMO Radar." International Journal of Antennas and Propagation 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/4171452.

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Target localization using a frequency diversity multiple-input multiple-output (MIMO) system is one of the hottest research directions in the radar society. In this paper, three-dimensional (3D) target localization is considered for two-dimensional MIMO radar with orthogonal frequency division multiplexing linear frequency modulated (OFDM-LFM) waveforms. To realize joint estimation for range and angle in azimuth and elevation, the range-angle-dependent beam pattern with high range resolution is produced by the OFDM-LFM waveform. Then, the 3D target localization proposal is presented and the corresponding closed-form expressions of Cramér-Rao bound (CRB) are derived. Furthermore, for mitigating the coupling of angle and range and further improving the estimation precision, a CRB optimization method is proposed. Different from the existing methods of FDA-based radar, the proposed method can provide higher range estimation because of multiple transmitted frequency bands. Numerical simulation results are provided to demonstrate the effectiveness of the proposed approach and its improved performance of target localization.

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Li, Xuyang, Zhiqiang Wan, Xiaozhe Wang, and Chao Yang. "Aeroelastic Optimization Design of the Global Stiffness for a Joined Wing Aircraft." Applied Sciences 11, no. 24 (December 12, 2021): 11800. http://dx.doi.org/10.3390/app112411800.

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Due to the complexity and particularity of the joined wing layout, traditional design methods for the global stiffness of a high-aspect wing are not applicable for a joined wing. Herein, a beam-frame model and a three-dimensional wing-box model are built to solve the global stiffness aeroelastic optimization design problem for a joined wing. The goal is to minimize the weight, and the constraints are the overall aeroelastic requirements. Based on a genetic algorithm, two methods for the beam-frame model and one method for the three-dimensional model are used for comparative analysis. The results show that the optimization method for a diagonal beam section and the optimization method for an exponential/linear combination function fit are adequate for optimizing and designating the joined wing global stiffness. The distributions obtained using the two methods have good consistency and are similar to the distribution of the three-dimensional model. The stiffness distribution data and the beam section parameters can be converted from each other, which is convenient for redesigning the structure parameters using the stiffness distribution data, and is valuable for engineering applications.

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Zhang, Jing, and Mingquan Zhou. "Repair Methods of Complex Holes in a Three-Dimensional Model Based on Variation Level Set." International Journal of Pattern Recognition and Artificial Intelligence 32, no. 06 (February 21, 2018): 1855007. http://dx.doi.org/10.1142/s0218001418550078.

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With regard to the numerous complex holes that accompany a three-dimensional (3D) model reconstruction, a hole-repair method is proposed in this paper. First, signed distance function (SDF) is constructed, and the curved surface where the hole is positioned is expressed by a static SDF. Another dynamic SDF is used to express the initial curved surface. Using a variation level set on implicit surfaces, we introduce a global convex optimization energy model to perform minimum inducement, thus turning the problem of extracting the hole edge into a problem of spherical evolution of a hidden surface. Finally, we consider the extracted hole-edge surface as the initial observation surface and complete the hole repair using convolution and synthesis. The experiment shows that this algorithm can effectively restore notable geometrical features of areas with complex holes and can repair the holes in a model with many grids.

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Zhou, Anwa, Zhibin Zhu, Hao Fan, and Qian Qing. "Three New Hybrid Conjugate Gradient Methods for Optimization." Applied Mathematics 02, no. 03 (2011): 303–8. http://dx.doi.org/10.4236/am.2011.23035.

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Amineh, Reza K., Ali Khalatpour, Haohan Xu, Yona Baskharoun, and Natalia K. Nikolova. "Three-Dimensional Near-Field Microwave Holography for Tissue Imaging." International Journal of Biomedical Imaging 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/291494.

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This paper reports the progress toward a fast and reliable microwave imaging setup for tissue imaging exploiting near-field holographic reconstruction. The setup consists of two wideband TEM horn antennas aligned along each other’s boresight and performing a rectangular aperture raster scan. The tissue sensing is performed without coupling liquids. At each scanning position, wideband data is acquired. Then, novel holographic imaging algorithms are implemented to provide three-dimensional images of the inspected domain. In these new algorithms, the required incident field and Green’s function are obtained from numerical simulations. They replace the plane (or spherical) wave assumption in the previous holographic methods and enable accurate near-field imaging results. Here, we prove that both the incident field and Green’s function can be obtained from a single numerical simulation. This eliminates the need for optimization-based deblurring which was previously employed to remove the effect of realistic non-point-wise antennas.

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Hwang, Feng-Nan. "Three-dimensional trajectory optimization for multi-stage launch vehicle mission using a full-space quasi-Lagrange–Newton method." ANZIAM Journal 60 (August 30, 2019): C172—C186. http://dx.doi.org/10.21914/anziamj.v60i0.14067.

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Many aerospace industrial applications require robust and efficient numerical solutions of large sparse nonlinear constrained parameter optimization problems arising from optimal trajectory problems. A three-dimensional multistage launcher problem is taken as a numerical example for studying the performance and applicability of the full-space Lagrange–Newton–Krylov method. The typical optimal trajectory, control history and other important physical qualities are presented, and the efficiency of the algorithm is also investigated. References J. T. Betts. Practical methods for optimal control and estimation using nonlinear programming. Advances in Design and Control. SIAM, 2nd edition, 2010. doi:10.1137/1.9780898718577. R. T. Marler and J. S. Arora. Survey of multi-objective optimization methods for engineering. Struct. Multidiscip. Opt., 26(6):369395, 2004. doi:10.1007/s00158-003-0368-6. W. Roh and Y. Kim. Trajectory optimization for a multi-stage launch vehicle using time finite element and direct collocation methods. Eng. Opt., 34:1532, 2002. doi:10.1080/03052150210912. G. D. Silveira and V. Carrara. A six degrees-of-freedom flight dynamics simulation tool of launch vehicles. J. Aero. Tech. Manag., 7:231239, 2015. doi:10.5028/jatm.v7i2.433. H.-H. Wang, Y.-S. Lo, F.-T. Hwang, and F.-N. Hwang. A full-space quasi-LagrangeNewtonKrylov algorithm for trajectory optimization problems. Electron. T. Numer. Anal., 49:103125, 2018. doi:10.1553/etna_vol49s103. H. Yang, F.-N. Hwang, and X.-C. Cai. Nonlinear preconditioning techniques for full-space Lagrange-Newton solution of PDE-constrained optimization problems. SIAM J. Sci. Comput., 38:A2756A2778, 2016. doi:10.1137/15M104075X.

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Pan, Hong, Wen Lei Sun, and Lian Ying He. "Three Dimensional Modeling and Aerodynamic Analysis of MW Wind Turbine Blade." Advanced Materials Research 305 (July 2011): 274–78. http://dx.doi.org/10.4028/www.scientific.net/amr.305.274.

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Wind turbine blade is one of the key components of wind turbine, and its aerodynamic performance largely determine the reliability of wind turbine. This paper use the momentum - blade element theory, and correction by Prandtl, Wilson correction, Glauert correction and other methods to modify the model of the blade to come to the aerodynamic model, then using the point of the coordinate transformation theory each the airfoil two dimensional coordinate will conversion into space coordinates, using UG of three-dimensional modeling software to model, and finally the aerodynamic performance of airfoil is analyzed. Through modeling and aerodynamic analysis, for the following structure optimization and control strategy laid a foundation.

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Han, Lin, Geng Liu, Xiaohui Yang, and Bing Han. "Dimensional and Layout Optimization Design of Multistage Gear Drives Using Genetic Algorithms." Mathematical Problems in Engineering 2020 (January 31, 2020): 1–19. http://dx.doi.org/10.1155/2020/3197395.

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In the minimal weight/volume design of multistage gear drives, both the dimensional and layout parameters of gear pairs have a direct effect on the design result. A new optimization model that can carry out both dimensional- and layout-constrained optimization design for any number of stages of cylindrical gear drives simultaneously is proposed. The optimization design of a three-stage cylindrical gear drive is conducted as a design example to test the application of this model. In the attempt to solve this constrained optimization problem using an elitist genetic algorithm (GA), different constraint handling methods have a crucial effect on the optimal results. Thus, the results obtained by applying three typical constraint handling methods in GA one by one are analyzed and compared to figure out which one performs the best and find the optimal solution. Moreover, a more precise projection center distance (PCD) method to calculate the degree of interference constraint violation is proposed and compared with the usually used (0, 1) method. The results show that the proposed PCD method is a better one.

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Rao, D. Bhaskara, and N. Ramesh Babu. "A rapid method for three‐dimensional modeling of magnetic anomalies." GEOPHYSICS 56, no. 11 (November 1991): 1729–37. http://dx.doi.org/10.1190/1.1442985.

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A computer program has been developed for three‐dimensional analysis of total field magnetic anomalies due to arbitrary polarization suitable for present‐day personal computers. A vertical sided prism with arbitrary polarization is used as a basic model. A nonlinear optimization technique based on Marquardt’s algorithm is used to estimate all parameters of the model. A combination of prisms is used to analyze more complex magnetic fields. Analytical methods are used to estimate the derivatives required in the simultaneous solutions of the normal equations. Methods have been developed to minimize the computing time in forward calculation as well as in inversion. Approximate equations have been derived for rapid calculation of magnetic anomalies and partial derivatives of anomalies of prismatic bodies, which are valid beyond short distances from the sources. The algorithm has been developed in such a way that the use of the exact and approximate equations may be efficiently monitored as a trade‐off between accuracy and speed. The method is applied to analyze a synthetic anomaly contour map and the total field aeromagnetic anomalies in the offshore region of Mahanadi basin, Orissa, India.

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Zhao, Yao Qiang, Yuan Hai Li, and Qing Fang Liu. "Optimization Analysis of Shallow Tunnel Excavation." Advanced Materials Research 243-249 (May 2011): 3599–605. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3599.

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In this paper, FLAC3D, the general software for geotechnical engineering project, is used to conduct two-dimensional numerical simulation for typical shallow tunnel excavation methods which include full-section method, the upper and lower step method, three-step method and CRD method etc.Effects of different excavation methods to the stability of tunnel surrounding rock are analyzed. The paper selected a subsistent tunnel as the research object. With construction simulation of different excavation methods, the paper makes comparative analysis of laws and characteristics of displacement of tunnel surrounding rock , stress distribution and size of plastic zones under different excavation methods. Study shows that: Ι.Followed by two step method, CRD engineering method and the full-section method successively, the three-step method is the best in the aspect of control of surrounding rock stress,; ΙΙ. Followed by full-section method, two- step method and the three step method successively, CRD engineering method is the best,in the aspect of size of plastic zones; Ш. Followed by three-step method, two-step method and the full-section method, CRD construction is the best in the aspect of control of surrounding rock displacement.

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Du, Juan, and Yuelin Long. "Landscape Image Layout Optimization Extraction Simulation of 3D Pastoral Complex under Big Data Analysis." Complexity 2020 (November 28, 2020): 1–11. http://dx.doi.org/10.1155/2020/6620216.

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Big data has brought about opportunities for landscape architecture, changing the design thinking of layout optimization simulation, expanding the platform for public participation in layout optimization simulation design, reflecting social and humanistic care, and promoting the integration of discipline cooperation and data. At the same time, it also brings about challenges. The proposal of data theory, the acquisition and analysis of data, and the protection of privacy are all issues that we need to face and solve. First, build a layout optimization simulation program under the background of big data. Follow the procedures of conventional layout optimization simulation, add big data analysis technology to the preliminary analysis, layout optimization simulation design, and later evaluation management, introduce new data processing methods, and build a theoretical framework of landscape optimization simulation methods that integrate new and traditional data. Second, studying the evolution of the landscape image layout of the three-dimensional pastoral complex is different: the overall landscape image layout of the three-dimensional pastoral complex shows a trend of fragmentation and heterogeneity. Among them, the arable land is gradually fragmented, the wetland and water area are simplified in form, the woodland and grassland patches are gradually distributed, the fragmentation is reduced by 76.19%, and the connectivity index is gradually increased. From a spatial perspective, the edge area outside the Fourth Ring Road becomes the most obvious area of fragmentation tendency. Finally, by introducing big data into the landscape layout optimization simulation, a layout optimization simulation method based on big data is constructed and used in the layout optimization simulation of the landscape image layout of the three-dimensional pastoral complex to guide the participatory layout optimization simulation.

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Zhang, Mengjian, Daoyin Long, Tao Qin, and Jing Yang. "A Chaotic Hybrid Butterfly Optimization Algorithm with Particle Swarm Optimization for High-Dimensional Optimization Problems." Symmetry 12, no. 11 (October 30, 2020): 1800. http://dx.doi.org/10.3390/sym12111800.

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In order to solve the problem that the butterfly optimization algorithm (BOA) is prone to low accuracy and slow convergence, the trend of study is to hybridize two or more algorithms to obtain a superior solution in the field of optimization problems. A novel hybrid algorithm is proposed, namely HPSOBOA, and three methods are introduced to improve the basic BOA. Therefore, the initialization of BOA using a cubic one-dimensional map is introduced, and a nonlinear parameter control strategy is also performed. In addition, the particle swarm optimization (PSO) algorithm is hybridized with BOA in order to improve the basic BOA for global optimization. There are two experiments (including 26 well-known benchmark functions) that were conducted to verify the effectiveness of the proposed algorithm. The comparison results of experiments show that the hybrid HPSOBOA converges quickly and has better stability in numerical optimization problems with a high dimension compared with the PSO, BOA, and other kinds of well-known swarm optimization algorithms.

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Gülich, J. F. "Impact of three-dimensional phenomena on the design of rotodynamic pumps." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 1 (January 1, 1999): 59–70. http://dx.doi.org/10.1243/0954406991522185.

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Three-dimensional Navier—Stokes calculations are expected to be increasingly applied in the future for performance improvement of rotodynamic pumps. Frequently such an optimization process involves a preliminary design—based on one-dimensional methods and empirical data—which is subsequently optimized by computational fluid dynamics (CFD). Employing an empirical database is not only necessary in order to provide a good starting point for the CFD analysis but also to ensure that the design has a good chance of fulfilling part load requirements, since recirculating flows at the impeller inlet and outlet are not easily handled by CFD programs. CFD calculations provide the specific work input to the fluid and information on losses and reveal the complex three-dimensional flow patterns. The designer is faced with the task of interpreting such data and drawing conclusions for the optimization of the impeller. It is the purpose of the present contribution to analyse and describe the impact of various geometric parameters and flow features on the velocity distribution in the impeller and their influence on performance and part load characteristics. Criteria are also provided to select the parameters for the preliminary design. Hydraulic impeller losses calculated by CFD programs may often be misleading if the non-uniformity of the flow distribution at the impeller outlet is ignored. Procedures to quantify such mixing losses in the diffuser or volute downstream of the impeller are discussed.

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MONOKROUSOS, ANTONIOS, ESPEN ÅKERVIK, LUCA BRANDT, and DAN S. HENNINGSON. "Global three-dimensional optimal disturbances in the Blasius boundary-layer flow using time-steppers." Journal of Fluid Mechanics 650 (March 18, 2010): 181–214. http://dx.doi.org/10.1017/s0022112009993703.

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The global linear stability of the flat-plate boundary-layer flow to three-dimensional disturbances is studied by means of an optimization technique. We consider both the optimal initial condition leading to the largest growth at finite times and the optimal time-periodic forcing leading to the largest asymptotic response. Both optimization problems are solved using a Lagrange multiplier technique, where the objective function is the kinetic energy of the flow perturbations and the constraints involve the linearized Navier–Stokes equations. The approach proposed here is particularly suited to examine convectively unstable flows, where single global eigenmodes of the system do not capture the downstream growth of the disturbances. In addition, the use of matrix-free methods enables us to extend the present framework to any geometrical configuration. The optimal initial condition for spanwise wavelengths of the order of the boundary-layer thickness are finite-length streamwise vortices exploiting the lift-up mechanism to create streaks. For long spanwise wavelengths, it is the Orr mechanism combined with the amplification of oblique wave packets that is responsible for the disturbance growth. This mechanism is dominant for the long computational domain and thus for the relatively high Reynolds number considered here. Three-dimensional localized optimal initial conditions are also computed and the corresponding wave packets examined. For short optimization times, the optimal disturbances consist of streaky structures propagating and elongating in the downstream direction without significant spreading in the lateral direction. For long optimization times, we find the optimal disturbances with the largest energy amplification. These are wave packets of Tollmien–Schlichting waves with low streamwise propagation speed and faster spreading in the spanwise direction. The pseudo-spectrum of the system for real frequencies is also computed with matrix-free methods. The spatial structure of the optimal forcing is similar to that of the optimal initial condition, and the largest response to forcing is also associated with the Orr/oblique wave mechanism, however less so than in the case of the optimal initial condition. The lift-up mechanism is most efficient at zero frequency and degrades slowly for increasing frequencies. The response to localized upstream forcing is also discussed.

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LIU, RUOCHEN, PING ZHANG, and LICHENG JIAO. "QUANTUM PARTICLE SWARM OPTIMIZATION CLASSIFICATION ALGORITHM AND ITS APPLICATIONS." International Journal of Pattern Recognition and Artificial Intelligence 28, no. 02 (March 2014): 1459004. http://dx.doi.org/10.1142/s0218001414590046.

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Data processing in high-dimensional spaces is a challenging task. In order to effectively classify the data in a high-dimensional space, a quantum particle swarm optimization classification algorithm (QPSOCA) for high-dimensional datasets is proposed in this paper. In QPSOCA, an uncorrelated discriminant analysis algorithm is utilized to reduce the dimension of the data, which is implemented automatically and no extra parameters are needed. In addition, to avoid the randomness of the swarm and improve the convergence speed, quantum computation is introduced into particle swarm optimization (PSO). In the experimental section, a detailed comparison of three different combinatorial optimization methods is given to demonstrate the efficiency of the proposed algorithm. Comparative experiments show that the proposed algorithm can improve the classification accuracy.

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Liu, Rui, Yuanbin Mo, Yanyue Lu, Yucheng Lyu, Yuedong Zhang, and Haidong Guo. "Swarm-Intelligence Optimization Method for Dynamic Optimization Problem." Mathematics 10, no. 11 (May 25, 2022): 1803. http://dx.doi.org/10.3390/math10111803.

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In recent years, the vigorous rise in computational intelligence has opened up new research ideas for solving chemical dynamic optimization problems, making the application of swarm-intelligence optimization techniques more and more widespread. However, the potential for algorithms with different performances still needs to be further investigated in this context. On this premise, this paper puts forward a universal swarm-intelligence dynamic optimization framework, which transforms the infinite-dimensional dynamic optimization problem into the finite-dimensional nonlinear programming problem through control variable parameterization. In order to improve the efficiency and accuracy of dynamic optimization, an improved version of the multi-strategy enhanced sparrow search algorithm is proposed from the application side, including good-point set initialization, hybrid algorithm strategy, Lévy flight mechanism, and Student’s t-distribution model. The resulting augmented algorithm is theoretically tested on ten benchmark functions, and compared with the whale optimization algorithm, marine predators algorithm, harris hawks optimization, social group optimization, and the basic sparrow search algorithm, statistical results verify that the improved algorithm has advantages in most tests. Finally, the six algorithms are further applied to three typical dynamic optimization problems under a universal swarm-intelligence dynamic optimization framework. The proposed algorithm achieves optimal results and has higher accuracy than methods in other references.

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Faybusovich, L. "Infinite-Dimensional Quadratic Optimization: Interior-Point Methods and Control Applications." Applied Mathematics and Optimization 36, no. 1 (July 1, 1997): 43–66. http://dx.doi.org/10.1007/s002459900054.

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Faybusovich, L., and J. B. Moore. "Infinite-dimensional quadratic optimization: Interior-point methods and control applications." Applied Mathematics & Optimization 36, no. 1 (July 1997): 43–66. http://dx.doi.org/10.1007/bf02683337.

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Mao, Jia, and Wei Hua Zhang. "Simplified Three-Dimensional Thermomechanical Applications of Ball Grid Array Package." Advanced Materials Research 403-408 (November 2011): 256–65. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.256.

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Three dimensional finite element models were created utilizing APDL (ANSYS Parametric Design Language) for typical multi-chip BGAP (Ball Grid Array Packages) with different sizes to analyze the structure stress and strain when loading steady thermal loads upon them. Subsequently an improved modeling approach including equivalent beam and critical solder ball joint for simplification was studied and introduced. The Darveaux method based on plastic deformation energy accumulation for predicting fatigue life of solder ball joint under thermal cyclic loading was applied to the improved model for calculation, and effects of main design parameters upon fatigue life were studied accordingly. The numerical results reflected the stress distribution and varying traits of the package, compare of results between improved model and detailed model indicates that the simplified modeling method is quite effective and available for different types of analysis. Methods and results of this paper are of certain reference value for the design and optimization for similar kind of packages.

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Morgenstern, U., R. Steinmeier, and F. Uhlemann. "Objective Evaluation of Three-dimensional Image Registration Algorithms – Tools for Optimization and Evaluation." Methods of Information in Medicine 43, no. 04 (2004): 367–70. http://dx.doi.org/10.1055/s-0038-1633879.

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Summary Objective: The registration of medical volume data sets plays an important role when different images or modalities are used during computer-assisted surgical procedures. Nevertheless, it is often questionable how robust and accurate the underlying algorithms really are. Therefore, the goal is to foster the establishment of methods for an objective evaluation. Method: To reliably calculate the accuracy of registration algorithms, a reference transformation must be known. Due to the unknown perfect registration for real clinical data, the simulation of realistic data and successive affine transformations are employed. The simulation is based on models of the respective imaging modality where the dominant physical effects are taken into account. This gives the user full control over all simulation and transformation parameters. Finally, suitable quality measures are applied which allow a systematic evaluation of image registration accuracy by comparing the known theoretical result and the transformation calculated by the algorithm under investigation. Results: During the development of a new registration algorithm, the presented method proved to be a very valuable tool for optimization and evaluation of registration accuracy, since it allows objective numerical comparison of the calculated results. Conclusions: The presented method can be used during the development of algorithms for optimization and for quantitative comparison of different registration schemes. The respective software tool can automatically generate and transform simulated but realistic data. Employing suitable numerical quality measures, an objective evaluation of registration results can be easily obtained. Still, the validity of the relatively simple models has to be verified to draw reliable conclusions with respect to real data.

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Gordon, R., and Y. Levy. "Optimization of Wall Cooling in Gas Turbine Combustor Through Three-Dimensional Numerical Simulation." Journal of Engineering for Gas Turbines and Power 127, no. 4 (September 20, 2005): 704–23. http://dx.doi.org/10.1115/1.1808432.

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This paper is concerned with improving the prediction reliability of CFD modeling of gas turbine combustors. CFD modeling of gas turbine combustors has recently become an important tool in the combustor design process, which till now routinely used the old “cut and try” design practice. Improving the prediction capabilities and reliability of CFD methods will reduce the cycle time between idea and a working product. The paper presents a 3D numerical simulation of the BSE Ltd. YT-175 engine combustor, a small, annular, reversal flow type combustor. The entire flow field is modeled, from the compressor diffuser to turbine inlet. The model includes the fuel nozzle, the vaporizer solid walls, and liner solid walls with the dilution holes and cooling louvers. A periodic 36 deg sector of the combustor is modeled using a hybrid structured/unstructured multiblock grid. The time averaged Navier-Stokes (N-S) equations are solved, using the k-ε turbulence model and the combined time scale (COMTIME)/PPDF models for modeling the turbulent kinetic energy reaction rate. The vaporizer and liner walls’ temperature is predicted by the “conjugate heat transfer” methodology, based on simultaneous solution of the heat transfer equations for the vaporizer and liner walls, coupled with the N-S equations for the fluids. The calculated results for the mass flux passing through the vaporizer and various holes and slots of the liner walls, as well as the jet angle emerging from the liner dilution holes, are in very good agreement with experimental measurements. The predicted location of the liner wall hot spots agrees well with the position of deformations and cracks that occurred in the liner walls during test runs of the combustor. The CFD was used to modify the YT-175 combustion chamber to eliminate structural problems, caused by the liner walls overheating, that were observed during its development.

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He, Xiao, and Xinqian Zheng. "Performance improvement of transonic centrifugal compressors by optimization of complex three-dimensional features." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 14 (October 20, 2016): 2723–38. http://dx.doi.org/10.1177/0954410016673395.

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Transonic centrifugal compressors with high efficiency and wide stable flow range are required in modern gas turbine engines. Blade design with complex three-dimensional features is one of the promising methods to further improve the performance of such cases. Aiming to increase the efficiency while maintaining similar level of the stable flow range, this article investigates aerodynamic potentials of complex three-dimensional features in a transonic centrifugal compressor by multi-point and multi-objective optimizations, in which the camber curves, the sweep feature, and the lean feature have been optimized. During the first round of optimizations, the aforementioned three groups of variables are optimized individually, and their sensitivities to the performance have been analyzed. When optimizing the camber curves, the best result shows an end-bend feature at the front of the hub section, and the efficiency is improved by 1.0% due to the lowered shock strength. When optimizing the sweep feature, the best result presents an S-shape leading edge and a forward sweep feature. The efficiency is increased by 0.5% because of the reduced wake region. The optimized lean feature only improves the efficiency by 0.2%, which shows its relatively low potential. The final round of optimizations couples both the camber curves and the sweep feature, and the best geometry combines both the end-bend and S-shape leading edge patterns. The peak efficiency and the choke mass flow rate have been increased by 2.2% and 8.1%, respectively, which is owing to the combination of the lowered shock strength by optimized camber curves and the reduced wake region by optimized sweep feature. The result indicates significant potential of complex three-dimensional features to improve the performance of transonic centrifugal compressors.

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Wang, Jie, Yulin Zhou, Zhirong Guo, and Haifeng Liu. "Neutron spectrum unfolding using three artificial intelligence optimization methods." Applied Radiation and Isotopes 147 (May 2019): 136–43. http://dx.doi.org/10.1016/j.apradiso.2019.03.009.

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Tutueva, Aleksandra, and Denis Butusov. "Stability Analysis and Optimization of Semi-Explicit Predictor–Corrector Methods." Mathematics 9, no. 19 (October 3, 2021): 2463. http://dx.doi.org/10.3390/math9192463.

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The increasing complexity of advanced devices and systems increases the scale of mathematical models used in computer simulations. Multiparametric analysis and study on long-term time intervals of large-scale systems are computationally expensive. Therefore, efficient numerical methods are required to reduce time costs. Recently, semi-explicit and semi-implicit Adams–Bashforth–Moulton methods have been proposed, showing great computational efficiency in low-dimensional systems simulation. In this study, we examine the numerical stability of these methods by plotting stability regions. We explicitly show that semi-explicit methods possess higher numerical stability than the conventional predictor–corrector algorithms. The second contribution of the reported research is a novel algorithm to generate an optimized finite-difference scheme of semi-explicit and semi-implicit Adams–Bashforth–Moulton methods without redundant computation of predicted values that are not used for correction. The experimental part of the study includes the numerical simulation of the three-body problem and a network of coupled oscillators with a fixed and variable integration step and finely confirms the theoretical findings.

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Journal articles on the topic 'Methods of three-dimensional optimization'

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