Optimal Computing Budget Allocation for Particle Swarm Optimization in Stochastic Optimization

Simultaneous Reconstruction of Multiple Time-Varying Thermal Properties Based on Translucent Materials

In the realm of high-tech materials and energy applications, accurately measuring the transient heat flow at media boundaries and the internal thermal conductivity of materials in harsh heat exchange environments poses a significant challenge when using conventional direct measurement methods. Consequently, the study of photothermal parameter reconstruction in translucent media, which relies on indirect measurement techniques, has crucial practical value. Current research on reconstructing photothermal properties within participating media typically focuses on single-objective or time-invariant properties. There is a pressing need to develop effective methods for the simultaneous reconstruction of time-varying thermal flow fields and internal thermal conductivity at the boundaries of participating media. This paper introduces a computational model based on the numerical simulation theory of internal heat transfer systems in participating media, stochastic particle swarm optimization algorithms, and Kalman filter technology. The model aims to enable the simultaneous reconstruction of various thermal parameters within the target medium. Our results demonstrate that under varying levels of measurement noise, the inversion results for different target parameters exhibit slight oscillations around the true values, leading to a reduction in reconstruction accuracy. However, overall, the model demonstrates robustness and accuracy in ideal conditions, validating its effectiveness.

Seismic Model Parameter Optimization for Building Structures

Structural dynamic modeling is a key element in the analysis of building behavior for different environmental factors. Having this in mind, the authors propose a simple nonlinear model for studying the behavior of buildings in the case of earthquakes. Structural analysis is a key component of seismic design and evaluation. It began more than 100 years ago when seismic regulations adopted static analyzes with lateral loads of about 10% of the weight of the structure. Due to the dynamics and non-linear response of the structures, advanced analytical procedures were implemented over time. The authors’ approach is the following: having a nonlinear dynamic model (in this case, a multi-segment inverted pendulum on a cart with mass-spring-damper rotational joints) and at least two datasets of a building, the parameters of the building’s model are estimated using optimization algorithms: Particle Swarm Optimization (PSO) and Differential Evolution (DE). Not having much expertise on structural modeling, the present paper is focused on two aspects: the proposed model’s performance and the optimization algorithms performance. Results show that among these algorithms, the DE algorithm outperformed its counterpart in most situations. As for the model, the results show us that it performs well in prediction scenarios.

Dual-Environmental Particle Swarm Optimizer in Noisy and Noise-Free Environments

Particle swarm optimizer (PSO) is a population-based optimization technique applied to a wide range of problems. In the literature, many PSO variants have been proposed to deal with noise-free or noisy environments, respectively. While in real-life applications, noise emerges irregularly and unpredictably. As a result, PSO for a noise-free environment loses its accuracy when noise exists, while PSO for a noisy environment wastes its resampling resource when noise does not exist. To handle such scenario, a PSO variant that can work well in both noise-free and noisy environments is required, which does, to the authors' best knowledge, not exist yet. To fill such gap, this work proposes a novel PSO variant named as dual-environmental PSO (DEPSO). It uses a weighted search center based on top- k elite particles to guide the swarm. It averages their positions rather than resampling fitness values of particles to achieve noise reduction, which challenges the indispensable role of the resampling method in a noisy environment and adapts to a noise-free environment as well. Two theoretical analyses are presented for noise reduction and finer local optimization capabilities. Experimental results performed on CEC2013 benchmark functions indicate that DEPSO outperforms state-of-the-art PSO variants in both noise-free and noisy environments.