536 research outputs found
Improved Multi-Population Differential Evolution for Large-Scale Global Optimization
Differential evolution (DE) is an efficient population-based search algorithm with good robustness, however, it is challenged to deal with high-dimensional problems. In this paper, we propose an improved multi-population differential evolution with best-and-current mutation strategy (mDE-bcM). The population is divided into three subpopulations based on the fitness values, each of subpopulations uses different mutation strategy. After crossover, mutation and selection, all subpopulations are updated based on the new fitness values of their individuals. An improved mutation strategy is proposed, which uses a new approach to generate base vector that is composed of the best individual and current individual. The performance of mDE-bcM is evaluated on a set of 19 large-scale continuous optimization problems, a comparative study is carried out with other state-of-the-art optimization techniques. The results show that mDE-bcM has a competitive performance compared to the contestant algorithms and better efficiency for large-scale optimization problems
Particle shape effect on heat transfer performance in an oscillating heat pipe
The effect of alumina nanoparticles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally. A binary mixture of ethylene glycol (EG) and deionized water (50/50 by volume) was used as the base fluid for the OHP. Four types of nanoparticles with shapes of platelet, blade, cylinder, and brick were studied, respectively. Experimental results show that the alumina nanoparticles added in the OHP significantly affect the heat transfer performance and it depends on the particle shape and volume fraction. When the OHP was charged with EG and cylinder-like alumina nanoparticles, the OHP can achieve the best heat transfer performance among four types of particles investigated herein. In addition, even though previous research found that these alumina nanofluids were not beneficial in laminar or turbulent flow mode, they can enhance the heat transfer performance of an OHP
A Real-time Non-contact Localization Method for Faulty Electric Energy Storage Components using Highly Sensitive Magnetometers
With the wide application of electric energy storage component arrays, such
as battery arrays, capacitor arrays, inductor arrays, their potential safety
risks have gradually drawn the public attention. However, existing technologies
cannot meet the needs of non-contact and real-time diagnosis for faulty
components inside these massive arrays. To solve this problem, this paper
proposes a new method based on the beamforming spatial filtering algorithm to
precisely locate the faulty components within the arrays in real-time. The
method uses highly sensitive magnetometers to collect the magnetic signals from
energy storage component arrays, without damaging or even contacting any
component. The experimental results demonstrate the potential of the proposed
method in securing energy storage component arrays. Within an imaging area of
80 mm 80 mm, the one faulty component out of nine total components can
be localized with an accuracy of 0.72 mm for capacitor arrays and 1.60 mm for
battery arrays
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