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排序方式: 共有515条查询结果,搜索用时 15 毫秒
41.
Deepak Sharma Kalyanmoy Deb N. N. Kishore 《Structural and Multidisciplinary Optimization》2011,43(4):541-554
Genetic algorithms (GAs) can precisely handle the discrete structural topology optimization of single-piece elastic structures
called compliant mechanisms. The initial population of these elastic structures is mostly generated by assigning the material
at random. This causes disconnected or unfeasible designs and further rule-based repairing can result in representation degeneracy.
However, the problem-specific initial population can affect the performance of GAs like other operators. In this paper, a
domain-specific initial population strategy is developed that generates geometrically feasible structures for path generating
compliant mechanisms (PGCMs). It is coupled with the elitist non-dominated sorting genetic algorithm (NSGA-II) which has been
customized for structural topology optimization. The performance of initial population strategy over random initialization
using customized NSGA-II is checked on single and bi-objective optimization problems. Based on the results, it is observed
that the custom initialization outperforms the random initialization by dominating all the solutions and exploring larger
area of posed objectives. The elastic structures obtained by solving two examples of PGCMs using domain specific initial population
strategy are also presented. 相似文献
42.
The optical transmission of Tl3 As Se3 as a function of wavelength and temperature is reported for the 1.2 – 2.5 um spectral range, and at temperatures from 40 to 300K. The absorption edge for the material occurs at about 1.011 eV. The material also indicated direct transitions at about 1.015 eV and indirect transitions at about 1.001 eV. The direct and indirect transitions are found to be independent of temperature. Electrical measurements have identified the sample as p-type, with hole concentrations of 5 × 1015 and 6 × 1012 cm?3 at 395 and 300K, respectively. The sample seems to be a good insulator at all temperatures between 40 ?300K. 相似文献
43.
Md. Mahbubur Rahman Narayan Chandra Deb Nath Jae-Joon Lee 《Israel journal of chemistry》2015,55(9):990-1001
Electrochemical impedance spectroscopy (EIS) is a very powerful tool for elucidation of charge transfer and transport processes in sensitization-based solar cells (e.g., dye-sensitized solar cells [DSSCs], quantum dot-sensitized solar cells [QDSSCs], and perovskite solar cells [PSCs]). EIS measures the electrochemical response to small amplitude AC signals over a wide range of frequencies. Analysis of the EIS response provides information about the corresponding parameters of the cells. Here, we review the fundamentals of EIS, charge transport kinetic processes, and equivalent circuit models of sensitization-based solar cells and use these concepts to explain the EIS spectra of DSSCs, QDSSCs, and PSCs. This review will be very useful for understanding the fundamental charge transfer and transport processes in different sensitization-based solar cells and the use of an equivalent circuit model to interpret the observed charge transfer and reactions. 相似文献
44.
45.
Due to the flexibility in adapting to different fitness landscapes, self-adaptive evolutionary algorithms (SA-EAs) have been gaining popularity in the recent past. In this paper, we postulate the properties that SA-EA operators should have for successful applications in real-valued search spaces. Specifically, population mean and variance of a number of SA-EA operators such as various real-parameter crossover operators and self-adaptive evolution strategies are calculated for this purpose. Simulation results are shown to verify the theoretical calculations. The postulations and population variance calculations explain why self-adaptive genetic algorithms and evolution strategies have shown similar performance in the past and also suggest appropriate strategy parameter values, which must be chosen while applying and comparing different SA-EAs 相似文献
46.
Amir Hossein Gandomi Siamak Talatahari Xin‐She Yang Suash Deb 《The Structural Design of Tall and Special Buildings》2013,22(17):1330-1349
A new metaheuristic optimization algorithm is developed to solve truss optimization problems. The new algorithm, called cuckoo search (CS), is examined by solving five truss design optimization problems with increasing numbers of design variables and complexity in constraints. The performance of the CS algorithm is further compared with various classical and advanced algorithms, selected from a wide range of the state‐of‐the‐art algorithms in the area. The results identify that the final solutions obtained by the CS are superior compared with the best solutions obtained by the other algorithms. Finally, the unique search features used in the CS and the implications for future researches are discussed in detail. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
47.
48.
S.K. Deb 《Solar Energy Materials & Solar Cells》1992,25(3-4)
During the past two decades, electrochromic phenomena in transition metal oxides have been very widely studied. This unique phenomenon of electrically induced reversible coloration and charge storage in this films has diverse applications that range from information display to neural networking in optical computation. Electrochromic devices using metal oxides can be classified into two broad categories (1) all-solid-state systems, and (2) semi-solid systems involving wet electrolytes. The principles underlying the operation of both systems appear quite similar, but there remain both scientific and technological issues that are poorly understood. In this paper we briefly discuss some of the opportunities and challenges for the application of electrochromic phenomena in transition metal oxides. 相似文献
49.
50.
S. Reaz Ahmed S. K. Deb Nath M. Wahhaj Uddin 《International journal for numerical methods in engineering》2005,64(6):729-750
Optimum design of tire‐tread sections is an important practical issue. However, useful study of the problem that can suggest a reliable guideline for determining the optimum tread sections had hardly been made in the past. The present paper describes a new analysis of the state of stresses in tire‐tread sections in contact with the road surface, taking special care of the boundary conditions. Based on the analysis, a method is proposed to determine the optimum tread shapes for avoiding lateral slippage between tires and roads. The displacement potential function formulation, an ideal mathematical model for the practical stress problems, has been used in conjunction with finite‐difference method of solution. For the present analysis, lateral slipping in absence of frictional resistance as well as the no‐slip conditions of the tire‐tread contact surface have been considered along with a large number of tread aspect ratios. The present computational approach proves to be a powerful tool for determining the optimum tread shapes for avoiding the lateral slippage of tire‐treads. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献