Optimization method in material bodies cloaking with respect to static physical fields

2019 ◽  
Vol 27 (6) ◽  
pp. 845-857 ◽  
Author(s):  
Gennady V. Alekseev ◽  
Dmitry A. Tereshko
Keyword(s):  
Inverse Problems ◽  
Single Layer ◽  
Optimization Method ◽  
Control Problems ◽  
Optimization Analysis ◽  
Design Problems ◽  
Electrical Conductivities ◽  
Physical Fields ◽  
Material Bodies

Abstract Inverse problems associated with designing cylindrical DC electrical cloaking shells are studied. Using the optimization method, these inverse problems are reduced to corresponding control problems in which electrical conductivities play the role of passive controls. Admissibility of the optimization method for solving inverse design problems is justified. A numerical algorithm based on the particle swarm optimization is proposed, and the results of numerical experiments are discussed. Optimization analysis shows that high cloaking efficiency of the shell can be achieved either using a highly anisotropic single-layer shell or using a multilayer shell with isotropic layers. In the latter case, the resulting cloaking shell admits simple technological realization using natural materials.

On Measures of Coupling Between the Artifact and Controller Optimal Design Problems

2009 ◽  
Author(s):  
Diane L. Peters ◽  
Panos Y. Papalambros ◽  
A. Galip Ulsoy
Keyword(s):  
System Optimization ◽  
Optimization Method ◽  
Ease Of Use ◽  
Control Problems ◽  
Design Problems ◽  
Sensitivity Equations ◽  
Smart Products ◽  
Two Measures ◽  
And Control ◽  
Artifact Design

Optimization of smart products requires optimizing both the artifact design and its controller. The presence of coupling between the design and control problems is an important consideration in choosing the system optimization method. Several measures of coupling have been proposed based on different viewpoints of the system. In this paper, two measures of coupling, a vector based on optimality conditions and a matrix derived from an extension of the global sensitivity equations, are shown to be related under certain conditions and to be consistent in their coupling determination. The measures’ physical interpretation and relative ease of use are discussed using the example of a positioning gantry. A further relation is derived between one measure and a modified sequential formulation that would give results sufficiently close to the true solutions.

Multi-Objective Design Problem of Tire Wear and Visualization of Its Pareto Solutions2

2006 ◽  
Vol 34 (3) ◽  
pp. 170-194 ◽  
Author(s):  
M. Koishi ◽  
Z. Shida
Keyword(s):  
Inverse Problems ◽  
Conceptual Design ◽  
Dimensional Space ◽  
Design Stage ◽  
Objective Functions ◽  
Pareto Solutions ◽  
Design Problems ◽  
Multi Objective ◽  
Design Engineers ◽  
Design Variables

Abstract Since tires carry out many functions and many of them have tradeoffs, it is important to find the combination of design variables that satisfy well-balanced performance in conceptual design stage. To find a good design of tires is to solve the multi-objective design problems, i.e., inverse problems. However, due to the lack of suitable solution techniques, such problems are converted into a single-objective optimization problem before being solved. Therefore, it is difficult to find the Pareto solutions of multi-objective design problems of tires. Recently, multi-objective evolutionary algorithms have become popular in many fields to find the Pareto solutions. In this paper, we propose a design procedure to solve multi-objective design problems as the comprehensive solver of inverse problems. At first, a multi-objective genetic algorithm (MOGA) is employed to find the Pareto solutions of tire performance, which are in multi-dimensional space of objective functions. Response surface method is also used to evaluate objective functions in the optimization process and can reduce CPU time dramatically. In addition, a self-organizing map (SOM) proposed by Kohonen is used to map Pareto solutions from high-dimensional objective space onto two-dimensional space. Using SOM, design engineers see easily the Pareto solutions of tire performance and can find suitable design plans. The SOM can be considered as an inverse function that defines the relation between Pareto solutions and design variables. To demonstrate the procedure, tire tread design is conducted. The objective of design is to improve uneven wear and wear life for both the front tire and the rear tire of a passenger car. Wear performance is evaluated by finite element analysis (FEA). Response surface is obtained by the design of experiments and FEA. Using both MOGA and SOM, we obtain a map of Pareto solutions. We can find suitable design plans that satisfy well-balanced performance on the map called “multi-performance map.” It helps tire design engineers to make their decision in conceptual design stage.

UNCERTAINTY BASED ROBUST OPTIMIZATION IN AERODYNAMICS

2009 ◽  
Vol 23 (03) ◽  
pp. 477-480 ◽  
Author(s):  
ZHILI TANG
Keyword(s):  
Nash Equilibrium ◽  
Robust Design ◽  
Single Point ◽  
Optimization Method ◽  
Equilibrium Solutions ◽  
Design Problems ◽  
Nash Equilibrium Solutions ◽  
Definition Of ◽  
Taguchi Robust Design ◽  
Statistical Definition

The Taguchi robust design concept is combined with the multi-objective deterministic optimization method to overcome single point design problems in Aerodynamics. Starting from a statistical definition of stability, the method finds, Nash equilibrium solutions for performance and its stability simultaneously.

scholarly journals Iridescent structural colour production in male blue-black grassquit feather barbules: the role of keratin and melanin

2009 ◽  
Vol 6 (suppl_2) ◽  
Author(s):  
Rafael Maia ◽  
João Victor O Caetano ◽  
Sônia N Báo ◽  
Regina H Macedo
Keyword(s):  
Thin Film ◽  
Natural Variation ◽  
Single Layer ◽  
Coherent Scattering ◽  
Interspecific Variation ◽  
Stray Light ◽  
Main Role ◽  
Minimum Number ◽  
Keratin Layer

Iridescent coloration plays an important role in the visual communication system of many animal taxa. It is known that iridescent structural colours result from layers of materials with different refractive indexes, which in feathers usually are keratin, melanin and air. However, the role of these materials in the production of structural iridescent coloration is still poorly documented. Despite the great interspecific variation in the organization of such structures in bird plumage, melanin layers are usually considered too opaque, suggesting its main role is to delineate the outermost keratin layer and absorb incoherently scattered stray light. We combined spectrometry, electron microscopy and thin-film optical modelling to describe the UV-reflecting iridescent colour of feather barbules of male blue-black grassquits ( Volatinia jacarina ), characterized by a keratin layer overlying a single melanin layer. Our models indicate that both the keratin and the melanin layers are essential for production of the observed colour, influencing the coherent scattering of light. The melanin layer in some barbules may be thin enough to allow interaction with the underlying keratin; however, individuals usually have, on an average, the minimum number of granules that optimizes absorbance by this layer. Also, we show that altering optical properties of the materials resulted in better-fitting models relative to the empirically measured spectra. These results add to previous findings concerning the influence of melanin in single-layer iridescence, and stress the importance of considering natural variation when characterizing such photonic structures.

Shape-driven control of layer height in robotic wire and arc additive manufacturing

2019 ◽  
Vol 25 (10) ◽  
pp. 1637-1646 ◽  
Author(s):  
Bohao Xu ◽  
Xiaodong Tan ◽  
Xizhi Gu ◽  
Donghong Ding ◽  
Yuelin Deng ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Deposition Rate ◽  
Control Method ◽  
Single Layer ◽  
Optimization Method ◽  
Content Type ◽  
Layer Height ◽  
Layer Deposition ◽  
Complex Shapes ◽  
The Difference

Purpose Once an uneven substrate is aligned, traditional control theories and methods can be used on it, so aligning is of great significance for the development of wire and arc additive manufacturing (WAAM). This paper aims to propose a shape-driven control method for aligning a substrate with slopes to expand the application of WAAM. Design/methodology/approach A substrate with slopes must be aligned by depositing weld beads with slopes. First, considering the large height differences of slopes, multi-layer deposition is needed, and the number of layer of weld beads must be ascertained. Second, the change in the deposition rate is controlled as a ramp function to generate weld beads with slopes. Third, the variation of the deposition rate must be fine-tuned to compensate for the deviation between the actual and theoretical layer heights at the deposition of each layer. Finally, the parameters of the ramp functions at the deposition of each layer are determined through an optimization method. Findings First, to model the response function of layer height to deposition rate, the experiments are conducted with the deposition rate jumping from 4 to 8 mm/s and from 8 to 4 mm/s. When the deposition rate jumps from 4 to 8 mm/s and from 8 to 4 mm/s, the difference in the height of each layer decreases as the number of layer increases. Second, the variation of the deposition rate can be fine-tuned based on the deviation between the measured and theoretical layer heights because the variation of the deposition rate is proportional to the layer height when the initial and end deposition rates are near 4 or 8 mm/s, respectively. Third, the experimental results demonstrate that the proposed method is effective for single-layer aligning and aligning a substrate with one or more slopes. Originality/value The proposed method can expand the application of WAAM to an uneven substrate with slopes and lays the foundation for aligning tasks focused on uneven substrates with more complex shapes.

scholarly journals Here, there and everywhere – the importance of neutral lipids in plant growth and development

2021 ◽  
Author(s):  
Agnieszka Zienkiewicz ◽  
Marta Saldat ◽  
Krzysztof Zienkiewicz
Keyword(s):  
Life Cycle ◽  
Neutral Lipids ◽  
Single Layer ◽  
Pollen Grains ◽  
Dynamic Nature ◽  
Plant Life ◽  
Plant Environment ◽  
Plant Life Cycle ◽  
Diverse Plant

In plants, lipids serve as one of the major and vital cellular constituents. Neutral lipids reserves play an essential role in the plant life cycle by providing carbon and energy equivalents for periods of active metabolism. The most common form of lipid storage are triacylglycerols (TAGs) packed into specialized organelles called lipid droplets (LDs). They have been observed in diverse plant organs and tissues, like oil seeds or pollen grains. LDs consist of a core, composed mostly of TAGs, enclosed by a single layer of phospholipids that is decorated by a unique set of structural proteins. Moreover, the recent advances in exploration of LDs proteome revealed a plethora of diverse proteins interacting with LDs. This is likely the result of a highly dynamic nature of these organelles and their involvement in many diverse aspect of cellular metabolism, tightly synchronized with plant developmental programs and directly related to plant-environment interactions. In this review we summarize and discuss the current progress in understanding the role of LDs and their cargo during plants life cycle, with a special emphasis on developmental aspects.

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