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Test and Analysis on the Interference to the CBTC Systems by Wi-Fi Signals
Li Ming,Wang Hua-shen,Zhao Hong-li,Zhu Li 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.3
Communication-Based Train Control (CBTC) system is an automated train control system using bidirectional train-ground communications to ensure the safe operation of rail vehicles. The interference from Wi-Fi signals to the CBTC signals has significant impacts on the train control performance. Most of previous works use data from simulation platform. This paper proposes a method to test the Wi-Fi interference to the Communication Based Train Control(CBTC) systems. The test is made mainly based on real subway, and supplemented by laboratory simulation platform. The collected data is to be compared and analyzed. The test result shows that the signal transmission mode of waveguide is the most reliable, followed by the leaky cable. The transmission mode of free wave has the worst anti-interference capability to Wi-Fi signals. This is because that both the waveguide and leaky cable transmission have a better encapsulation compared with the free space transmission. Also applying for specific bands can effectively reduce the interference transferred from Wi-Fi signals to the CBTC.
Li-Hua Zhu,Gang Li,Zhi-Qian Dong 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.2
The structural damage or collapse caused by weak-story failure mechanisms poses a great threat to the safety of human life and property under strong earthquakes. Many researchers have attempted to transform this unexpected failure mechanism into the desired overall failure mechanism by installing various energy dissipation devices on unsafe structures. This paper introduced a lattice-shaped friction device (LSFD), which is a friction device with hardening postyielding stiffness, into a steel frame with a weak-story failure mechanism. Then, shaking table tests of a three types of two-story steel frames—a frame with LSFDs, a frame with traditional friction brace dampers (FBDs), and a bare frame—were carried out. The seismic responses of the hardening postyielding stiffness of the LSFD on the weak-story failure mechanism of the frame were emphatically studied. The results showed that there was little difference in the seismic responses between the two damped structures under moderate and weak earthquakes. The distribution of maximum story drift for the structure with LSFDs was more uniform, which effectively suppressed the weak-story failure under strong earthquakes, whereas the structure with FBDs had serious deformation concentrations. The numerical simulation results of the structure with LSFDs in the shaking table test showed that the simplified model results were basically consistent with the experimental results. Hence, this model could be used to analyze the seismic performance of damped structures with LSFDs.
Exact solution for free vibration of curved beams with variable curvature and torsion
Zhu, Li-Li,Zhao, Ying-Hua,Wang, Guang-Xin Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.3
For the purpose of investigating the free vibration response of the spatial curved beams, the governing equations are derived in matrix formats, considering the variable curvature and torsion. The theory includes all the effects of rotary inertia, shear and axial deformations. Frobenius' scheme and the dynamic stiffness method are then applied to solve these equations. A computer program is coded in Mathematica according to the proposed method. As a special case, the dynamic stiffness and further the natural frequencies of a cylindrical helical spring under fixed-fixed boundary condition are carried out. Comparison of the present results with the FEM results using body elements in I-DEAS shows good accuracy in computation and validity of the model. Further, the present model is used for reciprocal spiral rods with different boundary conditions, and the comparison with FEM results shows that only a limited number of terms in the resultant provide a relatively accurate solution.
Exact solution for free vibration of curved beams with variable curvature and torsion
Li-li Zhu,Ying-hua Zhao,Guang-xin Wang 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.3
For the purpose of investigating the free vibration response of the spatial curved beams, the governing equations are derived in matrix formats, considering the variable curvature and torsion. The theory includes all the effects of rotary inertia, shear and axial deformations. Frobenius’ scheme and the dynamic stiffness method are then applied to solve these equations. A computer program is coded in Mathematica according to the proposed method. As a special case, the dynamic stiffness and further the natural frequencies of a cylindrical helical spring under fixed-fixed boundary condition are carried out. Comparison of the present results with the FEM results using body elements in I-DEAS shows good accuracy in computation and validity of the model. Further, the present model is used for reciprocal spiral rods with different boundary conditions, and the comparison with FEM results shows that only a limited number of terms in the resultant provide a relatively accurate solution.
An eigenspace projection clustering method for structural damage detection
Zhu, Jun-Hua,Yu, Ling,Yu, Li-Li Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.2
An eigenspace projection clustering method is proposed for structural damage detection by combining projection algorithm and fuzzy clustering technique. The integrated procedure includes data selection, data normalization, projection, damage feature extraction, and clustering algorithm to structural damage assessment. The frequency response functions (FRFs) of the healthy and the damaged structure are used as initial data, median values of the projections are considered as damage features, and the fuzzy c-means (FCM) algorithm are used to categorize these features. The performance of the proposed method has been validated using a three-story frame structure built and tested by Los Alamos National Laboratory, USA. Two projection algorithms, namely principal component analysis (PCA) and kernel principal component analysis (KPCA), are compared for better extraction of damage features, further six kinds of distances adopted in FCM process are studied and discussed. The illustrated results reveal that the distance selection depends on the distribution of features. For the optimal choice of projections, it is recommended that the Cosine distance is used for the PCA while the Seuclidean distance and the Cityblock distance suitably used for the KPCA. The PCA method is recommended when a large amount of data need to be processed due to its higher correct decisions and less computational costs.
Jin-Hua Liang,Luo Lu,Hua-Yuan Zhu,Wang Li,Lei Fan,Jian-Yong Li,Wei Xu 대한암학회 2019 Cancer Research and Treatment Vol.51 No.1
Purpose Determine the frequency and prognostic value of circulating Epstein-Barr virus (EBV) DNA copy number in angioimmunoblastic T-cell lymphoma (AITL) patients who were treated with dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin (DA-EPOCH) regimens. Materials and Methods Sixty newly-diagnosed AITL patients were retrospectively enrolled in the present study. All patients were treated with DA-EPOCH regimen. Results Twenty-two subjects (36.7%) had a EBV DNA-positive test at diagnosis. EBV DNApositive patients were associated with lower lymphocyte-monocyte ratio (p=0.024). Median followup was 40 months (range, 14 to 100 months). The overall response rate for all the 60 AITL patents were 71.7% (95% confidence interval [CI], 58.6 to 82.5) with 3-year progressivefree survival (PFS) rate of 30.9%±6.1% and overall survival (OS) rate of 60.1%±6.6%. Not only did PFS estimation differ between the EBV DNApositive and EBV DNAnegative group (hazard ratio [HR], 2.24; 95% CI, 1.15 to 4.35; p=0.006), but also worse OS was observed in the pretreatment EBV DNApositive group than in the EBV DNAnegative group (HR, 2.74; 95% CI, 1.22 to 6.19; p=0.006). EBV DNA test positivity was independent prognostic marker for both PFS (HR, 2.17; 95% CI, 1.17 to 4.00; p=0.014) and OS (HR, 3.24; 95% CI, 1.48 to 7.11; p=0.004) after adjusting International Prognostic Index and prognostic index for AITL score. Reduction in EBV copies was significantly associated with therapy-response. Conclusion Circulating EBV DNA level was an important prognostic and monitoring marker for AITL patients who treated with DA-EPOCH regimens which cannot improve outcomes for AITL patients.
An eigenspace projection clustering method for structural damage detection
Jun-hua Zhu,Ling Yu,Li-li Yu 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.2
An eigenspace projection clustering method is proposed for structural damage detection by combining projection algorithm and fuzzy clustering technique. The integrated procedure includes data selection, data normalization, projection, damage feature extraction, and clustering algorithm to structural damage assessment. The frequency response functions (FRFs) of the healthy and the damaged structure are used as initial data, median values of the projections are considered as damage features, and the fuzzy c-means (FCM) algorithm are used to categorize these features. The performance of the proposed method has been validated using a three-story frame structure built and tested by Los Alamos National Laboratory, USA. Two projection algorithms, namely principal component analysis (PCA) and kernel principal component analysis (KPCA), are compared for better extraction of damage features, further six kinds of distances adopted in FCM process are studied and discussed. The illustrated results reveal that the distance selection depends on the distribution of features. For the optimal choice of projections, it is recommended that the Cosine distance is used for the PCA while the Seuclidean distance and the Cityblock distance suitably used for the KPCA. The PCA method is recommended when a large amount of data need to be processed due to its higher correct decisions and less computational costs.
Jin-Hua Liang,Yun-Ping Zhang,Jun Xia,Chong-Yang Ding,Wei Wu,Li Wang,Lei Cao,Hua-Yuan Zhu,Lei Fan,Tian-Nv Li,Jian-Yong Li,Wei Xu 대한암학회 2019 Cancer Research and Treatment Vol.51 No.4
Purpose The purpose of this study was to investigate the prognostic significance of total metabolic tumor volume (TMTV) and total lesion glycolysis (TLG) in patients with follicular lymphoma (FL) at baseline and mid-treatment with 18F-fluorodeoxyglucose positron emission tomography computed tomography (PET-CT) scans. Materials and Methods The study analyzed data from 48 patients with FL who were treated in Jiangsu Province Hospital and reviewed their baseline PET-CT scans. TMTV and TLG were computed by using the absolute value of 2.0, 2.5, and 3.0 thresholding method, respectively. Results Median age was 53 years, 75.0% of patients had stage III to IV disease, 43.8% had a Follicular Lymphoma International Prognostic Index 1 (FLIPI1) score of 3 to 5 and 20.8% had a FLIPI2 score of 3 to 5. Receiver operating characteristic (ROC) curve analysis showed the optimal cut-off values for TMTV3.0 and TLG3.0 were 476.4 (sensitivity, 85.7%; specificity, 78.0%; area under the curve [AUC], 0.760; p=0.003) and 2,676.9 (sensitivity, 71.4%; specificity, 78.0%; AUC, 0.760; p=0.003). On multivariable analysis, TMTV3.0 and TLG3.0 were independent predictors of both progression-free survival (PFS) (hazard ratio [HR], 5.406; 95% confidence interval [CI], 1.326 to 22.040; p=0.019 and HR, 6.502; 95% CI, 1.079 to 39.182; p=0.042) and overall survival (OS) (HR, 4.111; 95% CI, 1.125 to 15.027; p=0.033 and HR, 5.885; 95% CI, 1.014 to 34.148; p=0.049). ROC curve analysis showed the optimal cut-off values for TMTV3.0 and TLG3.0 were 66.3% (sensitivity, 85.7%; specificity, 63.4%; AUC, 0.774; p < 0.001) and 64.5% (sensitivity, 85.7%; specificity, 65.9%; AUC, 0.777; p < 0.001). Conclusion Baseline TMTV and TLG are strong predictors of PFS and OS in FL. Furthermore, interim TMTV (TMTV > 66.3%) and TLG (TLG > 64.5%) reduction are valuable tools for early treatment response assessment in FL patients.