An Iterative Algorithm for Solving the Least-Squares Problem of Matrix Equation AXB+CYD=E

Kai-juan Shen,Chuan-hua You,Yu-xia Du 한국전산응용수학회 2008 Journal of applied mathematics & informatics Vol.26 No.5

In this paper, an iterative method is proposed to solve the least-squares problem of matrix equation AXB + CY D = E over un-known matrix pair [X, Y ]. By this iterative method, for any initial matrix pair [X1, Y1], a solution pair or the least-norm least-squares solution pair of which can be obtained within finite iterative steps in the absence of roundoff errors. In addition, we also consider the optimal approximation problem for the given matrix pair [X0, Y0] in Frobenius norm. Given numerical examples show that the algorithm is efficient. In this paper, an iterative method is proposed to solve the least-squares problem of matrix equation AXB + CY D = E over un-known matrix pair [X, Y ]. By this iterative method, for any initial matrix pair [X1, Y1], a solution pair or the least-norm least-squares solution pair of which can be obtained within finite iterative steps in the absence of roundoff errors. In addition, we also consider the optimal approximation problem for the given matrix pair [X0, Y0] in Frobenius norm. Given numerical examples show that the algorithm is efficient.

AN ITERATIVE ALGORITHM FOR SOLVING THE LEAST-SQUARES PROBLEM OF MATRIX EQUATION AXB+CYD=E

Shen, Kai-Juan,You, Chuan-Hua,Du, Yu-Xia Korean Society of Computational and Applied Mathem 2008 Journal of applied mathematics & informatics Vol.26 No.5

In this paper, an iterative method is proposed to solve the least-squares problem of matrix equation AXB+CYD=E over unknown matrix pair [X, Y]. By this iterative method, for any initial matrix pair [$X_1,\;Y_1$], a solution pair or the least-norm least-squares solution pair of which can be obtained within finite iterative steps in the absence of roundoff errors. In addition, we also consider the optimal approximation problem for the given matrix pair [$X_0,\;Y_0$] in Frobenius norm. Given numerical examples show that the algorithm is efficient.

Genetic Epidemiological Analysis of Esophageal Cancer in High-incidence Areas of China

Wang, Kai-Juan,Yang, Jun-Xia,Shi, Jia-Chen,Deng, Song-Yuan,Cao, Xiao-Qin,Song, Chun-Hua,Wang, Peng Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Genetic epidemiological studies have shown that genetic susceptibility to esophageal cancer (EC) is an important cause of its high incidence within families in some areas of China. The purpose of this study was to obtain evidence of a genetic basis of EC in Xin-an and Xin-xiang counties in China. Familial aggregation and complex segregation analyses were performed of 79 EC families in these counties. The heritability of EC was examined using Falconer's method and complex segregation analysis was conducted with the SEGREG program in Statistical Analysis for Genetic Epidemiology (SAGE version 5.3.1). The results showed that the distribution of EC in families did not fit well into a binomial distribution. The heritability of EC among first-degree and second-degree relatives was $67.0{\pm}7.31%$ and $43.1%{\pm}9.80%$, respectively, and the summing up powered heritability was $53.2{\pm}6.74%$. The segregation ratio was 0.045. Complex segregation analysis showed that the genetic model of EC was additive. The current results provide evidence for an inherited propensity to EC in certain high-risk groups in China, and support efforts to identify the genes that confer susceptibility to this disease.

The relationship between residential burglaries and urban environments in Taipei City: a data mining approach

Yi-Kai Juan,Wan-Hsuan Lin 서울시립대학교 도시과학연구원 2023 도시과학국제저널 Vol.27 No.1

Although the overall crime rate in Taiwan has shown a declining trend in recent years, the proportion of burglaries remains high. Most studies regarding the prevention of burglaries proceed from the perspectives of population composition or criminal psychology, and place focus on the internal spatial planning of buildings without mentioning the association between case locations and urban environments. In order to effectively prevent crime and improve the quality of life, this study utilized cases provided by the Taipei City Government Open Platform (Data. Taipei) to confirm the surrounding environmental factors and building data of burglary cases for data mining application. The proposed method consists of two phases: clustering and association rule mining. In the clustering phase, the key substructures of environmental information are collected; then characteristics in each cluster are analyzed based on the association rule. The results of analysis showed that the first group (Group 1) in the classification should give priority to improving the visibility of idle space and streets, while the second group (Group 2) should improve the efficiency of personnel surveillance and solve the problem of crowds caused by business activities. The third group (Group 3), which featured narrow lanes and insufficient street lamps on chaotic streets, should engage in overall planning and design. Some studies have found that the environmental characteristics of burglary cases in Taipei City are different from the characteristics of crime-saddled urban areas defined by international scholars. Such differences deserve further study. The findings of this study can serve as an environmental design model for future urban development.

New Strategy for Eliminating Zero-sequence Circulating Current between Parallel Operating Three-level NPC Voltage Source Inverters

Kai Li,Zhenhua Dong,Xiaodong Wang,Chao Peng,Fujin Deng,Josep M. Guerrero,Juan Vasquez 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

A novel strategy based on a zero common mode voltage pulse-width modulation (ZCMV-PWM) technique and zero-sequence circulating current (ZSCC) feedback control is proposed in this study to eliminate ZSCCs between three-level neutral point clamped (NPC) voltage source inverters, with common AC and DC buses, that are operating in parallel. First, an equivalent model of ZSCC in a three-phase three-level NPC inverter paralleled system is developed. Second, on the basis of the analysis of the excitation source of ZSCCs, i.e., the difference in common mode voltages (CMVs) between paralleled inverters, the ZCMV-PWM method is presented to reduce CMVs, and a simple electric circuit is adopted to control ZSCCs and neutral point potential. Finally, simulation and experiment are conducted to illustrate effectiveness of the proposed strategy. Results show that ZSCCs between paralleled inverters can be eliminated effectively under steady and dynamic states. Moreover, the proposed strategy exhibits the advantage of not requiring carrier synchronization. It can be utilized in inverters with different types of filter.

The MAP Kinase Kinase Gene AbSte7 Regulates Multiple Aspects of Alternaria brassicicola Pathogenesis

Kai Lu,Min Zhang,Ran Yang,Min Zhang,Qinjun Guo,Kwang-Hyun Baek,Hou-Juan Xu 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.2

Mitogen-activated protein kinase (MAPK) cascades in fungi are ubiquitously conserved signaling pathways that regulate stress responses, vegetative growth, pathogenicity, and many other developmental processes. Previously, we reported that the AbSte7 gene, which encodes a mitogen-activated protein kinase kinase (MAPKK) in Alternaria brassicicola, plays a central role in pathogenicity against host cabbage plants. In this research, we further characterized the role of AbSte7 in the pathogenicity of this fungus using ΔAbSte7 mutants. Disruption of the AbSte7 gene of A. brassicicola reduced accumulation of metabolites toxic to the host plant in liquid culture media. The ΔAbSte7 mutants could not efficiently detoxify cruciferous phytoalexin brassinin, possibly due to reduced expression of the brassinin hydrolase gene involved in detoxifying brassinin. Disruption of the AbSte7 gene also severely impaired fungal detoxification of reactive oxygen species. AbSte7 gene disruption reduced the enzymatic activity of cell walldegrading enzymes, including cellulase, β-glucosidase, pectin methylesterase, polymethyl-galacturonase, and polygalacturonic acid transeliminase, during host plant infection. Altogether, the data strongly suggest the MAPKK gene AbSte7 plays a pivotal role in A. brassicicola during host infection by regulating multiple steps, and thus increasing pathogenicity and inhibiting host defenses.

Metformin enhances the osteogenic activity of rat bone marrow mesenchymal stem cells by inhibiting oxidative stress induced by diabetes mellitus: an in vitro and in vivo study

Kai Dong,Wen-Juan Zhou,Zhong-Hao Liu 대한치주과학회 2023 Journal of Periodontal & Implant Science Vol.53 No.1

Purpose: The purpose of this study was to determine whether metformin (MF) could alleviate the expresssion of reactive oxygen species (ROS) and improve the osteogenic ability of bone marrow mesenchymal stem cells derived from diabetic rats (drBMSCs) in vitro, and to evaluate the effect of MF on the ectopic osteogenesis of drBMSCs in a nude mouse model in vivo. Methods: BMSCs were extracted from normal and diabetic rats. In vitro, a cell viability assay (Cell Counting Kit-8), tests of alkaline phosphatase (ALP) activity, and western blot analysis were first used to determine the cell proliferation and osteogenic differentiation of drBMSCs that were subjected to treatment with different concentrations of MF (0, 50, 100, 200, 500 μM). The cells were then divided into 5 groups: (1) normal rat BMSCs (the BMSCs derived from normal rats group), (2) the drBMSCs group, (3) the drBMSCs + Mito-TEMPO (10 μM, ROS scavenger) group, (4) the drBMSCs + MF (200 μM) group, and (5) the drBMSCs + MF (200 μM) + H2O2 (50 μM, ROS activator) group. Intracellular ROS detection, a senescenceassociated β-galactosidase assay, ALP staining, alizarin red staining, western blotting, and immunofluorescence assays were performed to determine the effects of MF on oxidative stress and osteogenic differentiation in drBMSCs. In vivo, the effect of MF on the ectopic osteogenesis of drBMSCs was evaluated in a nude mouse model. Results: MF effectively reduced ROS levels in drBMSCs. The cell proliferation, ALP activity, mineral deposition, and osteogenic-related protein expression of drBMSCs were demonstrably higher in the MF-treated group than in the non-MF-treated group. H2O2 inhibited the effects of MF. In addition, ectopic osteogenesis was significantly increased in drBMSCs treated with MF. Conclusions: MF promoted the proliferation and osteogenic differentiation of drBMSCs by inhibiting the oxidative stress induced by diabetes and enhenced the ectopic bone formation of drBMSCs in nude mice.

Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

Kai Sun,Rui-Juan Han,Li-Jun Ma,Li-Jun Wang,Li-Gang Li,Jiu-Hong Chen 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.6

Objective: To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Materials and Methods: Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 ± 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. Results: There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 ± 0.306 [group A] vs. 1.084 ± 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 ± 0.16 mSv in group A and 7.1 ± 1.05 mSv in group B (p = 0.001). Conclusion: In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure. Objective: To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Materials and Methods: Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 ± 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. Results: There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 ± 0.306 [group A] vs. 1.084 ± 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 ± 0.16 mSv in group A and 7.1 ± 1.05 mSv in group B (p = 0.001). Conclusion: In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

EFFECT OF SUBSTITUENTS IN THE IMIDAZOLIUM RING ON THE PERFORMANCE OF SOLID-STATE DYE-SENSITIZED SOLAR CELLS

Juan Li,ZHONG-SHENG WANG,KAI LV,HONG SUN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.5

Three solid-state imidazolium iodides have been designed and synthesized for use as all-solid-stateelectrolytes in solid-state dye-sensitized solar cells (ssDSSCs). The e®ect of substituents in theimidazolium ring on the ionic conductivity and solar cell performance of ssDSSCs has been inves-tigated. As compared to the methyl-ethyl-substituted imidazolium iodide, replacement of one alkylgroup (the methyl group) with an ester group increases the ionic conductivity and solar cell per-formance signi¯cantly, and further replacement of the other alkyl group (the ethyl group) with ahydroxyethyl group further increases the ionic conductivity and solar cell performance signi¯-cantly. A power conversion e±ciency of 7.45% has been achieved under the irradiation of simulatedAM1.5G solar light (100 mW cm? 2 ) with the ssDSSC using the hydroxyethyl and ester co-func-tionalized imidazolium iodide based solid-state electrolyte and a metal-free organic dye sensitizer.

Bond-Slip Behaviors Between BFRP Bar and Ecological High Ductility Concrete Using the Beam Test

Li-Juan Chai,Li-Ping Guo,Bo Chen,Zhu Li,Rui Ma,Kai Li 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.12

To better understand the design parameters of bridge deck link slab made by basalt fiber reinforced polymer (BFRP) bar and ecological high ductility concrete (Eco-HDC), the bond behaviors of BFRP bar embedded in Eco-HDC using beam test based on RILEM standard were studied. The beam specimens had variable factors namely diameter of BFRP bar, embedment length and cover thickness. The results indicate that most beam specimens display a failure mode of BFRP bar pulled out with specimen splitting. Besides, with the increase of diameter and embedment length, the bond strength decreases. While as the cover thickness increases, the bond strength and first bond stress show an increasing trend. The free end slip increases as the embedment length or cover thickness increases. In addition, the strain at loaded end is larger than that at free end as the load increases. Moreover, the formulas of bond strength and peak slip are proposed based on the test data of specimens. At last, embedment length and cover thickness of BFRP bar in the bridge deck link slab are recommended.