This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision te...This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision techniques, the translation is only known up to a scale factor, and a single scale factor is assumed for the whole sequence of images if only one camera is used. If an extra camera is available, stereo vision based reconstruction can be obtained by binocular views. If the baseline of the stereo setup is known, the scale factor problem is solved. We found that direct application of classical bundle adjustment on the constraints inherent between the binocular views has not been tested. Our method incorporated this constraint into the conventional bundle adjustment method. This special binocular bundle adjustment has been performed on image sequences similar to planet terrain circumstances. Experimental results show that our special method enhances not only the localization accuracy, but also the terrain mapping quality.展开更多
Objective. To determine the effects of losartan and captopril treatment on ventricular remodeling and function after myocardial infarction in rats. Methods. Thirty-two rats with MI induced by coronary ligation after s...Objective. To determine the effects of losartan and captopril treatment on ventricular remodeling and function after myocardial infarction in rats. Methods. Thirty-two rats with MI induced by coronary ligation after seven days were divided into four groups randomly and treated with captopril(2 g. liter-1, group A), losartan(10 mg. kg-1. d-1, group B), losartan(30 mg. kg-1. d-1,group C) and placebo (no drug, group D) for six weeks, respectively. Shamoperated rats(group E)served as controls. Echocardiography was performed at 1 and 7 weeks after MI, re- spectively. Results. Compared with the results before treatment,both LV end-diastolic internal diameter and volume decreased significantly and the thickened Posterior wall was reversed in group A, B and C; the peak early filling velocity decreased whereas the peak velocity was increased in these three groups. There are no significant difference among the three treated groups. However,LV end-diastolic internal diameter and the E/A were still increased,whereas the thickness of anterior wall and the peak velocity of LV outflow were decreased in group A,B,and C after treatment comparing with group E. Conclusion. Both angiotensin converting enzyme inhibitor and angiotensin II receptor antagonist can prevent the ventricular remodeling and improve the ventricular function.展开更多
This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as subchains.The planar five-bar metamorphic linkages that have three phases resulting from locking of motors are c...This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as subchains.The planar five-bar metamorphic linkages that have three phases resulting from locking of motors are considered.Under the assumption that the constraint exerted by the reconfigurable limb can switch between no constraint,a constraint force,and a constraint couple,the output motions of the metamorphic linkage in its two planar four-bar linkage phases are identified.By adding an appropriate joint to planar four-bar linkages with translational output,four planar five-bar linkages that can be employed in the construction of reconfigurable limbs are enumerated.Serial chains that can provide a constraint couple and a constraint force are synthesized based on screw theory.Reconfigurable limbs that have three configurations associated with the three distinct phases of the metamorphic linkages are assembled with planar five-bar metamorphic linkages and serial chains with four degrees of freedom.A class of reconfigurable parallel mechanisms are constructed by connecting a moving platform and a base with three identical reconfigurable limbs.The degrees of freedom of the reconfigurable parallel mechanism in different configurations with the metamorphic linkages in different phases are given.Finally,the actuation scheme for this kind of mechanisms is addressed.展开更多
基金the National Natural Science Foundation of China (Nos. 60505017 and 60534070)the Science Planning Project of Zhejiang Province, China (No. 2005C14008)
文摘This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision techniques, the translation is only known up to a scale factor, and a single scale factor is assumed for the whole sequence of images if only one camera is used. If an extra camera is available, stereo vision based reconstruction can be obtained by binocular views. If the baseline of the stereo setup is known, the scale factor problem is solved. We found that direct application of classical bundle adjustment on the constraints inherent between the binocular views has not been tested. Our method incorporated this constraint into the conventional bundle adjustment method. This special binocular bundle adjustment has been performed on image sequences similar to planet terrain circumstances. Experimental results show that our special method enhances not only the localization accuracy, but also the terrain mapping quality.
基金This study was supported by National Natural Science Foundation of China (39470313)
文摘Objective. To determine the effects of losartan and captopril treatment on ventricular remodeling and function after myocardial infarction in rats. Methods. Thirty-two rats with MI induced by coronary ligation after seven days were divided into four groups randomly and treated with captopril(2 g. liter-1, group A), losartan(10 mg. kg-1. d-1, group B), losartan(30 mg. kg-1. d-1,group C) and placebo (no drug, group D) for six weeks, respectively. Shamoperated rats(group E)served as controls. Echocardiography was performed at 1 and 7 weeks after MI, re- spectively. Results. Compared with the results before treatment,both LV end-diastolic internal diameter and volume decreased significantly and the thickened Posterior wall was reversed in group A, B and C; the peak early filling velocity decreased whereas the peak velocity was increased in these three groups. There are no significant difference among the three treated groups. However,LV end-diastolic internal diameter and the E/A were still increased,whereas the thickness of anterior wall and the peak velocity of LV outflow were decreased in group A,B,and C after treatment comparing with group E. Conclusion. Both angiotensin converting enzyme inhibitor and angiotensin II receptor antagonist can prevent the ventricular remodeling and improve the ventricular function.
基金supported by the National Natural Science Foundation of China(Grant Nos.51075025,51175029)Beijing Natural Science Foundation of China(Grant No.3132019)the Program for New Century Excellent Talents in University of China(Grant No.NCET-12-0769)
文摘This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as subchains.The planar five-bar metamorphic linkages that have three phases resulting from locking of motors are considered.Under the assumption that the constraint exerted by the reconfigurable limb can switch between no constraint,a constraint force,and a constraint couple,the output motions of the metamorphic linkage in its two planar four-bar linkage phases are identified.By adding an appropriate joint to planar four-bar linkages with translational output,four planar five-bar linkages that can be employed in the construction of reconfigurable limbs are enumerated.Serial chains that can provide a constraint couple and a constraint force are synthesized based on screw theory.Reconfigurable limbs that have three configurations associated with the three distinct phases of the metamorphic linkages are assembled with planar five-bar metamorphic linkages and serial chains with four degrees of freedom.A class of reconfigurable parallel mechanisms are constructed by connecting a moving platform and a base with three identical reconfigurable limbs.The degrees of freedom of the reconfigurable parallel mechanism in different configurations with the metamorphic linkages in different phases are given.Finally,the actuation scheme for this kind of mechanisms is addressed.
