Self-adapting control parameters in dynamic differential evolution on inverse scattering problems: SADDE for inverse scattering

[[abstract]]The application of two techniques for the reconstruction of shape reconstruction of the perfectly conducting cylinder from scattered field measurements is studied in the present paper. These approaches are applied to two-dimensional configurations. After an integral formulation, a discretization using the method of moment (MoM) is applied. The inverse scattering problems are transformed into optimization problems. Considering that the microwave imaging is recast as a nonlinear optimization problem, an objective function is defined by the norm of a difference between the measured scattered electric field and that calculated for an estimated the shape of the perfectly conducting cylinder. Thus, the shape of metallic cylinder can be obtained by minimizing the objective function. In order to solve this inverse scattering problem, two techniques are employed. The first is based on a dynamic differential evolution (DDE). The second is a new version of the DDE algorithm with self-adaptive control parameters (SADDE). Numerical results indicate that the self-adaptive dynamic differential evolution algorithm (SADDE) outperforms the DDE in terms of reconstruction accuracy.[[conferencetype]]國際[[conferencedate]]20110926~20110930[[conferencelocation]]Seoul, Kore

Application of finite-difference time domain and dynamic differential evolution for inverse scattering of a two-dimensional perfectly conducting cylinder in slab medium

[[abstract]]We apply the dynamic differential evolution (DDE) algorithm to solve the inverse scattering problem for which a two-dimensional perfectly conducting cylinder with unknown cross section is buried in a dielectric slab medium. The finite-difference time domain method is used to solve the scattering electromagnetic wave of a perfectly conducting cylinder. The inverse problem is resolved by an optimization approach, and the global searching scheme DDE is then employed to search the parameter space. By properly processing the scattered field, some electromagnetic properties can be reconstructed. One is the location of the conducting cylinder, the others is the shape of the perfectly conducting cylinder. This method is tested by several numerical examples, and it is found that the performance of the DDE is robust for reconstructing the perfectly conducting cylinder. Numerical simulations show that even when the measured scattered fields are contaminated with Gaussian noise, the quality of the reconstructed results obtained by the DDE algorithm is very good.[[incitationindex]]SCI[[booktype]]紙

Electromagnetic Imaging for Inhomogeneous Dielectric Cylinder Buried in a Slab Medium

[[abstract]]The electromagnetic imaging of inhomogeneous dielectric cylinders buried in a slab medium is investigated. Dielectric cylinders of unknown permittivities are buried in second space and scattered a group of unrelated waves incident from first space where the scattered field is recorded. By proper arrangement of the various unrelated incident field, the difficulties of ill-posedness and nonlinearity are circumvented, and the permittivity distribution can be reconstructed through simple matrix operations. The algorithm is based on the moment method and the unrelated illumination method. Numerical results are given to demonstrate the capability of the inverse algorithm. They also show that the permittivity distribution of the cylinders can be successfully reconstructed even when the permittivity is fairly large. Good reconstructed results are obtained even in the presence of additive Gaussian noise in measured data. In addition, the effect of noise on the reconstruction result is also investigated.[[notice]]補正完畢[[incitationindex]]EI[[booktype]]紙

Image reconstruction of inhomogeneous biaxial dielectric cylinders buried in a slab medium

100學年度研究獎補助論文[[abstract]]The image reconstruction of inhomogeneous biaxial dielectric cylinders buried in a slab medium is investigated. A biaxial dielectric cylinder of unknown permittivities buried in a slab scatters a group of unrelated incident waves from outside. The scattered field is recorded outside the slab. By proper arrangement of the various unrelated incident fields, the difficulties of ill-posedness and nonlinearity are circumvented, and the permittivity distribution can be reconstructed through simple matrix operations. The algorithm is based on the moment method and the unrelated illumination method. Numerical results are given to demonstrate the capability of the inverse algorithm. Good reconstructed results are obtained even in the presence of additive Gaussian random noise in measured data. In addition, the effect of noise on the reconstruction result is also investigated.[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]紙

Time Domain Image Reconstruction for a Buried 2D Homogeneous Dielectric Cylinder Using NU-SSGA

[[abstract]]This article presents an image reconstruction approach for a buried homogeneous cylinder with arbitrary cross-section in half space. The computational method combines the finite difference time domain (FDTD) method and non-uniform steady state genetic algorithm (NU-SSGA) to determine the shape and location of the subsurface scatterer with arbitrary shape. The FDTD-subgirdding technique is implemented for modeling the shape of the cylinder more closely. The inverse problem is reformulated into an optimization problem and the global searching scheme NU-SSGA with closed cubic-spline is then employed to search the parameter space. A set of representative numerical results is presented for demonstrating that the proposed approach is able to efficiently reconstruct the electromagnetic properties of homogeneous dielectric scatterer even when the initial guess is far from the exact one. In addition, the effects of Gaussian noises on imaging reconstruction are also investigated.[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]紙

Comparative Study of Some Population-based Optimization Algorithms on Inverse Scattering of a Two-Dimensional Perfectly Conducting Cylinder in Slab Medium

[[abstract]]The application of four techniques for the shape reconstruction of a 2-D metallic cylinder buried in dielectric slab medium by measured the cattered fields outside is studied in the paper. The finite-difference time-domain (FDTD) technique is employed for electromagnetic analyses for both the forward and inverse scattering problems, while the shape reconstruction problem is transformed into optimization one during the course of inverse scattering. Then, four techniques including asynchronous particle swarm optimization (APSO), PSO, dynamic differential evolution (DDE) and self-adaptive DDE (SADDE) are applied to reconstruct the location and shape of the 2-Dmetallic cylinder for comparative purposes. The statistical performances of these algorithms are compared. The results show that SADDE outperforms PSO, APSO and DDE in terms of the ability of exploring the optima. However, these results are considered to be indicative and do not generally apply to all optimization problems in electromagnetics.[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]紙本[[booktype]]電子

CircNet: a database of circular RNAs derived from transcriptome sequencing data

Circular RNAs (circRNAs) represent a new type of regulatory noncoding RNA that only recently has been identified and cataloged. Emerging evidence indicates that circRNAs exert a new layer of post-transcriptional regulation of gene expression. In this study, we utilized transcriptome sequencing datasets to systematically identify the expression of circRNAs (including known and newly identified ones by our pipeline) in 464 RNA-seq samples, and then constructed the CircNet database (http://circnet.mbc.nctu.edu.tw/) that provides the following resources: (i) novel circRNAs, (ii) integrated miRNA-target networks, (iii) expression profiles of circRNA isoforms, (iv) genomic annotations of circRNA isoforms (e.g. 282 948 exon positions), and (v) sequences of circRNA isoforms. The CircNet database is to our knowledge the first public database that provides tissue-specific circRNA expression profiles and circRNA–miRNA-gene regulatory networks. It not only extends the most up to date catalog of circRNAs but also provides a thorough expression analysis of both previously reported and novel circRNAs. Furthermore, it generates an integrated regulatory network that illustrates the regulation between circRNAs, miRNAs and genes

Immobilization of enzyme and antibody on ALD-HfO2-EIS structure by NH3 plasma treatment

Thin hafnium oxide layers deposited by an atomic layer deposition system were investigated as the sensing membrane of the electrolyte-insulator-semiconductor structure. Moreover, a post-remote NH3 plasma treatment was proposed to replace the complicated silanization procedure for enzyme immobilization. Compared to conventional methods using chemical procedures, remote NH3 plasma treatment reduces the processing steps and time. The results exhibited that urea and antigen can be successfully detected, which indicated that the immobilization process is correct