Assuming that the failure time under different risk factors follows the independent exponential distribution, a joint model under Type-I hybrid censoring is addressed in detail. Based on the Maximum likelihood estimat...Assuming that the failure time under different risk factors follows the independent exponential distribution, a joint model under Type-I hybrid censoring is addressed in detail. Based on the Maximum likelihood estimates （MLEs） of unknown parameters, we obtain exact distributions of MLEs by using the moment generating function （MGF）. Confidence intervals （CIs） of parameters are constructed through both the exact method and the parametric bootstrap method. Then we compare the performances of different methods by Monte Carlo simulations. Finally, the validity of the proposed models and methods are demonstrated by a numerical example.展开更多
As viewed from space remote-sensing images （e.g. Google Earth images） of South Guizhou and North Guangxi, the authors found that macroscopic karst landscape on the Earth＇s surface is strongly controlled by the Conj...As viewed from space remote-sensing images （e.g. Google Earth images） of South Guizhou and North Guangxi, the authors found that macroscopic karst landscape on the Earth＇s surface is strongly controlled by the Conjugated shear joint of ＂X＂ type. Joints of this kind constitute a huge infiltration network and act as channel-ways for the permeation of meteoric waters from the surface, thus, leading to the dissolution of carbonate rocks nearby. As a result, the karst landscape is formed, which is dominated by linear karst valleys. An ＂X＂ karst valley network structure appears in the area where horizontal strata are distributed, and a feather-like network structure appears in the area where vertical strata are distributed, respectively. When the water permeates downwards to the underground-water level, it will flow horizontally along the strike of ＂X＂ joints toward the local base level of erosion to form an ＂X＂ network system of underground conduits in the area where horizontal strata are distributed, but it is relatively complex, because of the joining of other joints. This is the first time we have made use of Google Earth images to study the karst environment. Therefore, it has been successful in research on the Earth＇s geomorphology, which could only rely on aerial photos and satellite photos in the past. Google Earth images provide low-cost and applicable imaging materials for the study of Earth＇s geomorphology and karst rocky desertification and its control.展开更多
We investigated bending moment resistance under diagonal compression load of comer doweled joints with plywood members. Joint members were made of ll-ply hardwood plywood of 19 mm thickness. Dowels were fabricated of ...We investigated bending moment resistance under diagonal compression load of comer doweled joints with plywood members. Joint members were made of ll-ply hardwood plywood of 19 mm thickness. Dowels were fabricated of Beech and Hornbeam species. Their diameters （6, 8 and 10 mm） and depths of penetration （9, 13 and 17 ram） in joint members were chosen variables in our experiment. By increasing the connector＇s diameter from 6 to 8 mm, the bending moment resistance under diagonal compressive load was increased, while it decreased when the diameter was increased from 8 to 10 mm. The bending moment re- sistance under diagonal compressive load was increased by increasing the dowel＇s depth of penetration. Joints made with dowels of Beech had higher resistance than dowels of Hornbeam. Highest resisting moment （45.18 N.m） was recorded for joints assembled with 8 mm Beech dowels penetrating 17 mm into joint members Lowest resisting moment （13.35 N.m） was recorded for joints assembled with 6 mm Hornbeam dowels and penetrating 9 mm into joint members.展开更多
Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some proba...Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some probabilistic distributions, incorporating the effect of the weld, five hundred random samples are generated. Statistical computational results of life of crack propagation and effect of change of crack shape are finally obtained and compared with experimental data available based on a regression analysis. Meanwhile, crack propagation behaviors are also investigated.展开更多
This paper proposes a scheme for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of a two-mode cavity field with a ∧-type three-level atom. In contrast with the previous...This paper proposes a scheme for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of a two-mode cavity field with a ∧-type three-level atom. In contrast with the previously proposed schemes, the present scheme is ascendant, since the fidelity is 1.0 and the joint measurement isn＇t needed. And the scheme is experimentally feasible based on the current cavity QED technique.展开更多
This paper develops a novel interval type-2 fuzzy Proportional-Derivative (PD) control scheme for electrically driven flexible-joint robots using the direct method of Lyapunov. The controller has a simple design in a ...This paper develops a novel interval type-2 fuzzy Proportional-Derivative (PD) control scheme for electrically driven flexible-joint robots using the direct method of Lyapunov. The controller has a simple design in a decentralized structure. Compared to the previous controllers reported for the flexible-joint robots which use two control loops, it has a simpler structure using only one control loop. It guarantees stability and provides a good tracking performance. The controller considers the whole robotic system including the manipulator and motors by applying the voltage control strategy. Stability analysis is presented and the effectiveness of the proposed control approach is demonstrated by simulations using a three link flexible-joint robot driven by permanent magnet DC motors. Simulation results show that the interval type-2 fuzzy PD controller can handle external disturbance better than the type-1 fuzzy PD controller. In addition, it spends less control effort than the type-1 in order to deal with disturbance.展开更多
基金Supported by the National Natural Science Foundation of China(No.71571144)Natural Science Basic Research Program of Shaanxi Province(2015JM1003)+1 种基金the Program of International Cooperation and Exchanges in Science and Technology Funded by Shanxi Province(2016KW-033)Shanxi Scholarship Council of China(2016-015)
文摘Assuming that the failure time under different risk factors follows the independent exponential distribution, a joint model under Type-I hybrid censoring is addressed in detail. Based on the Maximum likelihood estimates （MLEs） of unknown parameters, we obtain exact distributions of MLEs by using the moment generating function （MGF）. Confidence intervals （CIs） of parameters are constructed through both the exact method and the parametric bootstrap method. Then we compare the performances of different methods by Monte Carlo simulations. Finally, the validity of the proposed models and methods are demonstrated by a numerical example.
基金supported by theState Key Basic Research,Development and Planning Program (2006CB403202)Discipline Construction Foundation of Guizhou University
文摘As viewed from space remote-sensing images （e.g. Google Earth images） of South Guizhou and North Guangxi, the authors found that macroscopic karst landscape on the Earth＇s surface is strongly controlled by the Conjugated shear joint of ＂X＂ type. Joints of this kind constitute a huge infiltration network and act as channel-ways for the permeation of meteoric waters from the surface, thus, leading to the dissolution of carbonate rocks nearby. As a result, the karst landscape is formed, which is dominated by linear karst valleys. An ＂X＂ karst valley network structure appears in the area where horizontal strata are distributed, and a feather-like network structure appears in the area where vertical strata are distributed, respectively. When the water permeates downwards to the underground-water level, it will flow horizontally along the strike of ＂X＂ joints toward the local base level of erosion to form an ＂X＂ network system of underground conduits in the area where horizontal strata are distributed, but it is relatively complex, because of the joining of other joints. This is the first time we have made use of Google Earth images to study the karst environment. Therefore, it has been successful in research on the Earth＇s geomorphology, which could only rely on aerial photos and satellite photos in the past. Google Earth images provide low-cost and applicable imaging materials for the study of Earth＇s geomorphology and karst rocky desertification and its control.
文摘We investigated bending moment resistance under diagonal compression load of comer doweled joints with plywood members. Joint members were made of ll-ply hardwood plywood of 19 mm thickness. Dowels were fabricated of Beech and Hornbeam species. Their diameters （6, 8 and 10 mm） and depths of penetration （9, 13 and 17 ram） in joint members were chosen variables in our experiment. By increasing the connector＇s diameter from 6 to 8 mm, the bending moment resistance under diagonal compressive load was increased, while it decreased when the diameter was increased from 8 to 10 mm. The bending moment re- sistance under diagonal compressive load was increased by increasing the dowel＇s depth of penetration. Joints made with dowels of Beech had higher resistance than dowels of Hornbeam. Highest resisting moment （45.18 N.m） was recorded for joints assembled with 8 mm Beech dowels penetrating 17 mm into joint members Lowest resisting moment （13.35 N.m） was recorded for joints assembled with 6 mm Hornbeam dowels and penetrating 9 mm into joint members.
文摘Random fatigue of welded K-type tubular joints subjected to axial or out-of-plane bending load is analyzed. By considering the sizes of initial surface cracks and material constants as random variables with some probabilistic distributions, incorporating the effect of the weld, five hundred random samples are generated. Statistical computational results of life of crack propagation and effect of change of crack shape are finally obtained and compared with experimental data available based on a regression analysis. Meanwhile, crack propagation behaviors are also investigated.
基金Project supported by the National Natural Science Foundation of China （Grant No 10574022）, the Funds of the Natural Science of Fujian Province, China （Grant No Z0512006）.
文摘This paper proposes a scheme for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of a two-mode cavity field with a ∧-type three-level atom. In contrast with the previously proposed schemes, the present scheme is ascendant, since the fidelity is 1.0 and the joint measurement isn＇t needed. And the scheme is experimentally feasible based on the current cavity QED technique.
文摘This paper develops a novel interval type-2 fuzzy Proportional-Derivative (PD) control scheme for electrically driven flexible-joint robots using the direct method of Lyapunov. The controller has a simple design in a decentralized structure. Compared to the previous controllers reported for the flexible-joint robots which use two control loops, it has a simpler structure using only one control loop. It guarantees stability and provides a good tracking performance. The controller considers the whole robotic system including the manipulator and motors by applying the voltage control strategy. Stability analysis is presented and the effectiveness of the proposed control approach is demonstrated by simulations using a three link flexible-joint robot driven by permanent magnet DC motors. Simulation results show that the interval type-2 fuzzy PD controller can handle external disturbance better than the type-1 fuzzy PD controller. In addition, it spends less control effort than the type-1 in order to deal with disturbance.
