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Search Results: 1 - 10 of 201328 matches for " Qing Wang;Xiao-Wei Shi "
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An Improved Algorithm for Matrix Bandwidth and Profile Reduction in Finite Element Analysis
Qing Wang;Xiao-Wei Shi
PIER Letters , 2009, DOI: 10.2528/PIERL09042305
Abstract: In finite element analysis, methods for the solution of sparse linear systems of equations usually start out with reordering the coefficient matrix to reduce its bandwidth or profile. The location of pseudo-peripheral nodes is an important factor in the bandwidth and profile reduction algorithm. This paper presents a heuristic parameter, called the "width-depth ratio" and denoted by . With such a parameter, suitable pseudo-peripheral nodes could be found; the distance between which could be much close to or even to be the diameter of a graph compared with Gibbs-Poole-Stockmeyer (GPS) algorithm. As the new parameter was implemented in GPS algorithm, a novel bandwidth and profile reduction algorithm is proposed. Simulation results show that with the proposed algorithm bandwidth and profile could be reduced by as great as 33.33% and 11.65%, respectively, compared with the outcomes in GPS algorithm, while the execution time of both algorithms is close. Empirical results show that the proposed algorithm is superior to GPS algorithm in reducing bandwidth or profile.
A Generalized GPS Algorithm for Reducing the Bandwidth and Profile of a Sparse Matrix
Qing Wang;Yu-Chun Guo;Xiao-Wei Shi
PIER , 2009, DOI: 10.2528/PIER09010512
Abstract: A generalized GPS (GGPS) algorithm is proposed for the problem of reducing the bandwidth and profile of the stiffness matrix in finite element problems. The algorithm has two key-points. Firstly and most importantly, more pseudo-peripheral nodes are found, used as the origins for generating more level structures, rather than only two level structures in the GPS (Gibbs-Poole-Stockmeyer) algorithm. A new level structure is constructed with all the level structures rooted at the pseudo-peripheral nodes, leading to a smaller level width than the level width of any level structure's in general. Secondly, renumbering by degree is changed to be sum of the adjacent nodes codes to make a better renumbering in each level. Simulation results show that the GGPS algorithm can reduce the bandwidth by about 37.63% and 8.91% and the profiles by 0.17% and 2.29% in average for solid models and plane models, respectively, compared with the outcomes of GPS algorithm. The execution time is close to the GPS algorithm. Empirical results show that the GGPS is superior to the GPS in reducing bandwidth and profile.
A Novel Low Pass Filter Using Elliptic Shape Defected Ground Sstructure
Xiao-Qun Chen;Rui Li;Shang-Jie Shi;Qing Wang;Le Xu;Xiao-Wei Shi
PIER B , 2008, DOI: 10.2528/PIERB08071801
Abstract: This paper presents a novel elliptic shape defected ground structure (DGS) for low pass filter (LPF) applications. An equivalent RLC circuit model is presented and its corresponding parameters are also extracted from the measured S-parameters. The filter presents the advantages of compact size,high selectivity; low insertion loss and high out-band suppression from 5.15 GHz to 10 GHz below -31 dB. Good agreement with response of equivalent circuit, electromagnetic simulation, and measurement is demonstrated.
A Tunable 1.4-2.5 GHz Bandpass Filter Based on Single Mode
YanYi Wang;Feng Wei;He Xu;Xiao-Wei Shi
PIER , 2013, DOI: 10.2528/PIER12111704
Abstract: A new type of varactor-tuned microstrip bandpass filter (BPF) based on a single 1/2 resonator is investigated. The proposed resonator is composed of a transmission line with both ends short-ended and two varactors inserted symmetrically in the middle section. The variation of coupling coefficient can be controlled by using an inductor. With the proposed structure, it is easy to adjust the external quality factor of the filter and to control the bandwidth. Extra dc-block capacitors for the input and output ports are not necessary because the design of the proposed tunable 1/2 resonator makes the varactor act as both a frequency tuning element and a dc-block circuit. The proposed BPF is found to have the advantages of compact size, low insertion loss, large tuning range and good linearity.
Comparison of Endoscopic Ultrasonography and Multislice Spiral Computed Tomography for the Preoperative Staging of Gastric Cancer - Results of a Single Institution Study of 610 Chinese Patients
Xing-yu Feng, Wei Wang, Guang-yu Luo, Jing Wu, Zhi-wei Zhou, Wei Li, Xiao-wei Sun, Yuan-fang Li, Da-zhi Xu, Yuan-xiang Guan, Shi Chen, You-qing Zhan, Xiao-shi Zhang, Guo-liang Xu, Rong Zhang, Ying-bo Chen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078846
Abstract: Background This study compared the performance of endoscopic ultrasonography (EUS) and multislice spiral computed tomography (MSCT) in the preoperative staging of gastric cancer. Methodology/Principal Findings A total of 610 patients participated in this study, all of whom had undergone surgical resection, had confirmed gastric cancer and were evaluated with EUS and MSCT. Tumor staging was evaluated using the Tumor-Node-Metastasis (TNM) staging and Japanese classification. The results from the imaging modalities were compared with the postoperative histopathological outcomes. The overall accuracies of EUS and MSCT for the T staging category were 76.7% and 78.2% (P=0.537), respectively. Stratified analysis revealed that the accuracy of EUS for T1 and T2 staging was significantly higher than that of MSCT (P<0.001 for both) and that the accuracy of MSCT in T3 and T4 staging was significantly higher than that of EUS (P<0.001 and 0.037, respectively). The overall accuracy of MSCT was 67.2% when using the 13th edition Japanese classification, and this percentage was significantly higher than the accuracy of EUS (49.3%) and MSCT (44.6%) when using the 6th edition UICC classification (P<0.001 for both values). Conclusions/Significance Our results demonstrated that the overall accuracies of EUS and MSCT for preoperative staging were not significantly different. We suggest that a combination of EUS and MSCT is required for preoperative evaluation of TNM staging.
An Efficient Approach for Multifrontal Algorithm to Solve Non-Positive-Definite Finite Element Equations in Electromagnetic Problems
Jin Tian;Zhi-Qing Lv;Xiao-Wei Shi;Le Xu;Feng Wei
PIER , 2009, DOI: 10.2528/PIER09070207
Abstract: A new method called Expanded Cholesky Method (ECM) is proposed in this paper. The method can be used to decompose sparse symmetric non-positive-definite finite element (FEM) matrices. There are some advantages of the ECM, such as low storage, simplicity and easy parallelization. Based on the method, multifrontal (MF) algorithm is applied in non-positive-definite FEM computation. Numerical results show that the hybrid ECM/MF algorithm is stable and effective. In comparison with Generalized Minimal Residual Method (GMRES) in FEM electromagnetic computation, hybrid ECM/MF technology has distinct advantages in precision. The proposed method can be used to calculate a class of non-positive-definite electromagnetic problems.
Novel Binary Search Algorithm of Backtracking for RFID Tag Anti-Collision
Xiaolin Shi;Feng Wei;Qiulin Huang;Li Wang;Xiao-Wei Shi
PIER B , 2008, DOI: 10.2528/PIERB08070802
Abstract: In RFID system, tag collision is a main problem for fast tag identification. On the base of binary search algorithm of backtracking, an enhanced binary anti-collision search algorithm for radio frequency identification (RFID) system is presented in this paper. By dynamically transferring the ID of the tag, the length of the data transferred can be decreased dramatically. Mathematical simulation result shows that compared with the binary search algorithm of backtracking, the proposed algorithm can save channel by more than 43.75% when handling multiple RFID tags simultaneously. Finally the proposed algorithm is successfully applied to a RFID device, which validates itself.
Design of a Novel Monopole UWB Antenna with a Notched Ground
Li Wang;Wei Wu;Xiao-Wei Shi;Feng Wei;Qiulin Huang
PIER C , 2008,
Abstract: In this paper,a novel compact monopole ultra-wideband (UWB) antenna with a notched ground is presented. To increase the impedance bandwidth,a notched ground is introduced. The parameters and the characteristics of the antenna are given. It shows good characteristics for UWB,and it satisfies the VSWR requirement of less than 2.0 in the frequency band from 2.55 GHz to more than 13 GHz. The measured radiation patterns show good omnidirectional performance and antenna gains across the operation bandwidth.
Numerical simulation of two-dimensional granular shearing flows and the friction force of a moving slab on the granular media

Cai Qing-Dong,Chen Shi-Yi,Sheng Xiao-Wei,

中国物理 B , 2011,
Abstract: This paper studies some interesting features of two-dimensional granular shearing flow by using molecular dynamic approach for a specific granular system. The obtained results show that the probability distribution function of velocities of particles is Gaussian at the central part, but diverts from Gaussian distribution nearby the wall. The macroscopic stress along the vertical direction has large fluctuation around a constant value, the non-zero average velocity occurs mainly near the moving wall, which forms a shearing zone. In the shearing movement, the volume of the granular material behaves in a random manner. The equivalent friction coefficient between moving slab and granular material correlates with the moving speed at low velocity, and approaches constant as the velocity is large enough.
Improved Differential Evolution Strategy for Antenna Array Pattern Synthesis Problems
Rui Li;Le Xu;Xiao-Wei Shi;Na Zhang;Zhi-Qing Lv
PIER , 2011, DOI: 10.2528/PIER11011814
Abstract: An Improved Differential Evolution (IDE) algorithm is proposed for optimization problems. With the novel mutant operation adopting sub-optimal individual, the convergence of Differential Evolution (DE) algorithm is accelerated without increasing the risk of premature. Five typical test functions are minimized using DE and IDE algorithms, and the results show the superior performance of IDE algorithm. Furthermore, the algorithm is applied to pattern synthesis of two antenna arrays. Broad nulls are formed in radiation pattern of a linear array to suppress broad-band interferences. In a microstrip patch array, the sidelobe level of array is decreased about 12.9 dB and the mainlobe can scan to the desired angle.
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