Pulmonary edema assessment is a key factor in monitoring and guiding the treatment of critically ill patients. To date, the methods available at the bedside to estimate the physiological correlation of pulmonary edema and extravascular pulmonary fluid are often unreliable or require invasive measurements. The aim of this article is to develop an imaging method of reliably assessing pulmonary edema by utilizing functional electrical impedance tomography. In this article, the Split-Bregman algorithm is used to solve the Total Variation (TV) minimization problem in EIT image reconstruction. A thorax model is constructed according to CT images of rats. Through simulation and experiment, the proposed method improves the quality of reconstructed image significantly compared with existing methods. A pulmonary edema experiment in rats is also carried out. The development of pulmonary edema is analyzed numerically through EIT images.
An optimization method utilizing a multistage genetic algorithm (MS-GA) and considering parameter variations has been proposed to obtain optimal design of one-dimensional dielectric bandgap(1D D-EBG) structures with a few periods in small packaging power distribution networks. One-dimensional finite method (1D FEM) is used to improve computational efficiency and iteration speed. MS-GA consists of 3 stages: In stage 1, the population was initialized by Hamming distance, and the fitness was calculated to determine the number of EBG period. In stage 2, genetic manipulation and sensitivity analysis were used to improve local search ability and obtain preliminary results. In stage 3, cubic spline interpolation and local integral were used to reconstruct the fitness evaluation function considering parameter deviation, adjust the results and obtain the optimal parameters. Three optimized target frequency bands with center frequencies of 2.4 GHz, 3.5 GHz and 28 GHz were optimized, and Pearson coefficient was used to analyze the correlation between the parameters to better understand the influence of parameter deviation on the optimization results. The achieved results meet the optimization object within the allowable range of parameter errors, and the parameter constraints were successfully met for all three designs, with their final dimensions below 20 mm. Three-dimensional full-wave simulation software was used to simulate and analyze the stopband bands, and the simulation results were consistent with the calculation results.
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