Combined Forecasting Model of Subgrade Settlement Based on Least Square Twin Support Vector Regession

GAO Hui,Song Qi-chao,Huang Jun 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.6

Due to the normal forecasting methods for subgrade settlement using observation data have different applicabilities, and the predicting results has bigger volatility and lower accuracy. The Combined forecasting model of subgrade settlement based on Least Square twin support vector regession is put forward in this paper. At the first, according to the basic settlement law of subgrade and characteristics of settlement curve, the growth curve with the S-type characteristics are choosed as single forcasting model; Then taking prediction results of each individual model as the least square support vector regression model input and to construct the combined forecasting model of subgrade settlement. The result of engineering practice shows that the proposed method has better prediction accuracy and stability.

Application of Twin Support Vector Regression in Subgrade Settlement Prediction

Gao Hui,Song Qi-chao,Huang Jun 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.7

Due to the normal forecasting methods for subgrade settlement using observation data have different applicabilities, and the predicting results has bigger volatility and lower accuracy. In view of the above problems, based on the twin support vector regression tool, the settlement prediction model is established by combining with the measured roadbed settlement data; The related parameters of the prediction model are given and compared with the standard support vector regression machine, the comparison tests show that the twins support vector regression is a new method to predict the settlement of the roadbed, and is superior in forecasting accuracy to the standard support vector regression.

Subgrade Settlement Prediction Based on Least Square Support Vector Regession and Real-coded Quantum Evolutionary Algorithm

GAO Hui,SONG Qi-chao,Huang Jun 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.7

Due to the normal forecasting methods for subgrade settlement using observation data have different applicabilities, and the predicting results has bigger volatility and lower accuracy. In view of the above problems, a method based on least square support vector regression (LSTSVR) and real-coded quantum evolutionary algorithm (RQEA) is proposed. Firstly, the LSTSVR parameter is chosen as a combinatorial optimization problem, and determining the objective function of the combinatorial optimization problem, then, using RQEA to solve the combinatorial optimization problem and optimize the LSTSVR parameters, Finaly, LSTSVR-RQEA is used to sovle the prediction of subgrade settlement. The simulation results show that RQEA is an effective method to select LSTSVR parameters, and has excellent performance when applied to the prediction of subgrade settlement.

Bright all-solution-processed CsPbBr3 perovskite light emitting diodes optimized by quaternary ammonium salt

Liu Ning,You Fangtian,Ji Chao,Gong Hongkang,Song Qi,Li Jiasen,Liang Chunjun,He Zhiqun 한국물리학회 2021 Current Applied Physics Vol.31 No.-

Perovskite light-emitting diodes (PeLEDs) prepared by the all-solution-process are gradually coming into view due to their low cost and flexible production process. However, the performance of CsPbBr3 device is limited by the high non-radiative recombination losses due to incomplete surface coverage and grain defects. Here a quaternary ammonium salt, tetrabutylammonium hexafluorophosphate (TBA-PF6) was simultaneously introduced into perovskite emission layers (CsPbBr3) and electron transport layer (TPBi (1,3,5-Tris(1-phenyl-1Hbenzimidazol- 2-yl) benzene) dissolved in ethyl acetate). As a result, the morphology and luminescence of CsPbBr3 films were improved, and the energy level of TPBi was more conducive to charge transport. Consequently, the maximum luminance and current efficiency of the modified green-emitting PeLEDs are improved. Furthermore, the optimized device had an operating life of more than 20 min at an initial luminance of 1230 cd/ m2. This work provides a simple and easy method to be scaled up for the development of low-cost all-solutionprocessed PeLEDs.

Correlation of the maximum shear stress with micro-mechanisms of ductile fracture for metals with high strength-to-weight ratio

Lou, Yanshan,Yoon, Jeong Whan,Huh, Hoon,Chao, Qi,Song, Jung-Han Elsevier 2018 International journal of mechanical sciences Vol.146 No.-

<P><B>Abstract</B></P> <P>Mechanisms of ductile fracture are investigated experimentally in a wide range of loading conditions from compressive upsetting to the balanced biaxial tension for two metals with high strength-to-density ratio of DP980 (t1.2) steel sheets and a bulk aluminum alloy of AA7075. Specimens are carefully designed to achieve various loading conditions from shear at low stress triaxiality to the balanced biaxial tension at high stress triaxiality for DP980, while both tensile and compressive tests are conducted for AA7075. Fractured specimen surfaces are analyzed macroscopically focusing on their relations with the maximum shear stress. It is observed that all the specimens tend to fail along the direction of the maximum shear stress in various loading states of plane strain compression, uniaxial compression, shear, uniaxial tension, plane strain tension and the balanced biaxial tension. Scanning electron microscope analyses of fracture surfaces are also conducted to explore the underlying mechanism of void coalescence since coalescence of voids is viewed as the last step of ductile fracture after nucleation and growth of voids. It is noted that fractured voids elongate along the direction of the maximum shear stress for all specimens with the stress triaxiality ranging from about −0.57 in compression to 0.67 in the balanced biaxial tension. The experiments of DP980 and AA7075 reveal that ductile fracture takes place along the direction of the maximum shear stress in the wide loading conditions of compressive upsetting, shear, uniaxial tension, plane strain tension and the balanced biaxial tension with stress triaxiality below 0.67. Thus, ductile fracture is expected to be governed by the maximum shear stress in these wide loading conditions of compression, shear and tension. It is suggested that effect of the maximum shear stress must be correctly coupled in modeling of ductile fracture in these loading conditions with uncoupled and coupled ductile fracture criteria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mechanisms of ductile fracture is investigated experimentally in the wide range of loading conditions from compressive upsetting to the tension of notched specimens for two lightweight metals of DP980 (t1.2) steel sheets and a bulk aluminum alloy of AA7075. </LI> <LI> All the specimens tend to fail along the direction of the maximum shear stress in various loading states of plane strain compression, uniaxial compression, shear, uniaxial tension and plane strain tension. </LI> <LI> Fractured voids elongate along the direction of the maximum shear stress for all specimens with the stress triaxiality ranging from negative in compression to 0.57 in the plane strain tension. </LI> <LI> The experiments of DP980 and AA7075 reveal that ductile fracture takes place along the direction of the maximum shear stress in the wide loading conditions of compressive upsetting, shear, uniaxial tension, and plane strain tension with stress triaxiality below 0.6. </LI> <LI> Effect of the maximum shear stress must be correctly coupled in modeling of ductile fracture in these loading conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Shear fracture takes place in wide loading conditions of tension, shear and compression. </P> <P>[DISPLAY OMISSION]</P>

Advanced Gastric Cancer and Perfusion Imaging Using a Multidetector Row Computed Tomography: Correlation with Prognostic Determinants

Huan Zhang,Zilai Pan,Lianjun Du,Chao Yan,Bei Ding,Qi Song,Huawei Ling,Kemin Chen 대한영상의학회 2008 Korean Journal of Radiology Vol.9 No.2

Objective: To investigate the relationship between the perfusion CT features and the clinicopathologically determined prognostic factors in advanced gastric cancer cases. Materials and Methods: A perfusion CT was performed on 31 patients with gastric cancer one week before surgery using a 16-channel multi-detector CT (MDCT) instrument. The data were analyzed with commercially available software to calculate tumor blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). The microvessel density (MVD), was evaluated by immunohistochemical staining of the surgical specimens with anti- CD34. All of the findings were analyzed prospectively and correlated with the clinicopathological findings, which included histological grading, presence of lymph node metastasis, serosal involvement, distant metastasis, tumor, node, metastasis (TNM) staging, and MVD. The statistical analyses used included the Student’s t-test and the Spearman rank correlation were performed in SPSS 11.5. Results: The mean perfusion values and MVD for tumors were as follows: BF (48.14 16.46 ml/100 g/min), BV (6.70 2.95 ml/100 g), MTT (11.75 4.02 s), PS (14.17 5.23 ml/100 g/min) and MVD (41.7 11.53). Moreover, a significant difference in the PS values was found between patients with or without lymphatic involvement (p = 0.038), as well as with different histological grades (p = 0.04) and TNM stagings (p = 0.026). However, BF, BV, MTT, and MVD of gastric cancer revealed no significant relationship with the clinicopathological findings described above (p > 0.05). Conclusion: The perfusion CT values of the permeable surface could serve as a useful prognostic indicator in patients with advanced gastric cancer. Objective: To investigate the relationship between the perfusion CT features and the clinicopathologically determined prognostic factors in advanced gastric cancer cases. Materials and Methods: A perfusion CT was performed on 31 patients with gastric cancer one week before surgery using a 16-channel multi-detector CT (MDCT) instrument. The data were analyzed with commercially available software to calculate tumor blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface (PS). The microvessel density (MVD), was evaluated by immunohistochemical staining of the surgical specimens with anti- CD34. All of the findings were analyzed prospectively and correlated with the clinicopathological findings, which included histological grading, presence of lymph node metastasis, serosal involvement, distant metastasis, tumor, node, metastasis (TNM) staging, and MVD. The statistical analyses used included the Student’s t-test and the Spearman rank correlation were performed in SPSS 11.5. Results: The mean perfusion values and MVD for tumors were as follows: BF (48.14 16.46 ml/100 g/min), BV (6.70 2.95 ml/100 g), MTT (11.75 4.02 s), PS (14.17 5.23 ml/100 g/min) and MVD (41.7 11.53). Moreover, a significant difference in the PS values was found between patients with or without lymphatic involvement (p = 0.038), as well as with different histological grades (p = 0.04) and TNM stagings (p = 0.026). However, BF, BV, MTT, and MVD of gastric cancer revealed no significant relationship with the clinicopathological findings described above (p > 0.05). Conclusion: The perfusion CT values of the permeable surface could serve as a useful prognostic indicator in patients with advanced gastric cancer.