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Flynn P.J. Jain A.K. 《IEEE transactions on pattern analysis and machine intelligence》1991,13(10):1066-1075
BONSAI, a model-based 3D object recognition system, is described. It identifies and localizes 3D objects in range images of one or more parts that have been designed on a computer-aided-design (CAD) system. Recognition is performed via constrained search of the interpretation tree, using unary and binary constraints (derived automatically from the CAD models) to prune the search space. Attention is focused on the recognition procedure, but the model-building, image acquisition, and segmentation procedures are also outlined. Experiments with over 200 images demonstrate that the constrained search approach to 3D object recognition has an accuracy comparable to that of previous systems 相似文献
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Xinjian Duan Mukesh Jain David S. Wilkinson 《Metallurgical and Materials Transactions A》2006,37(12):3489-3501
A heterogeneous finite element model with randomly distributed inhomogeneities has been developed for the determination of
the forming limit diagram (FLD) for thin aluminum sheet material based on the prediction of localized necking. The strength
difference between the inhomogeneities and the matrix is ascertained either from the fluctuation of the experimental stress-strain
curve or from a micromechanical analysis that uses a representative particle field. By changing the specimen geometry and
friction conditions, different stress states (or strain paths) are achieved. A plot of the critical Oyane fracture parameter
is used to identify the limit strain state. Also, a plot of equivalent plastic strain rate is used to distinguish the boundary
of intense shear bands and hence to identify where to take the measurement point. Both a plane stress model and a three-dimensional
(3-D) model are adopted to predict the shear banding phenomenon and hence the FLD. The predicted FLD agrees well with the
measurements from a recent round robin experimental FLD involving several independent research laboratories. The Taguchi method
is applied to assess how the various parameters involved in the heterogeneous model affect the calculated forming limit strain. 相似文献
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M. Jain 《Journal of Materials Science》1992,27(2):399-407
The evolution of dislocation structure during room-temperature, uniaxial, low-cycle fatigue of an overaged Al-Mg-Si alloy is studied. Ageing at 450°C produces a fine dispersion of Mg2Si precipitate particles. During fully reversed strain-controlled cyclic tests, these fine particles restrict deformation to local regions and a stable dislocation substructure is developed early in fatigue life. Substructural observations of hardening and saturation by transmission electron microscopy reveal extensive dislocation band formation on Mg2Si precipitate rods. Various microstructural features such as configuration of tangled dislocations, dislocation cells, precipitate morphologies, sizes, precipitate-free zones, etc., have been examined during cyclic hardening and saturation. The results have been analysed in terms of kinematic and isotropictype microstructural mechanisms. 相似文献
28.
Plastic instability in dual-pressure tube-hydroforming process 总被引:1,自引:0,他引:1
The tube-hydroforming process has become an indispensable manufacturing technique in recent years. Successful tube hydroforming requires bulging to take place without causing any type of instability such as bursting, wrinkling or buckling. The dual-pressure tube-hydroforming process was introduced to achieve a favorable tri-axial stress state in the deformation process. In this paper, the effect of applying counter pressure on plastic instability of thin-walled tubes is analyzed. It is concluded that in dual-pressure tube hydroforming, the onset of plastic instability is delayed and the ductility of the metal is increased. 相似文献
29.
ATM networks are quickly being adopted as backbones over various parts of the Internet. This article studies the dynamics and performance of the TCP/IP protocol over the ABR and UBR services of ATM networks. Specifically the buffering requirements in the ATM switches as well as the ATM edge devices. It is shown that with a good switch algorithm, ABR pushes congestion to the edges of the ATM network while UBR leaves it inside the ATM portion. As a result, the switch ABR buffer requirement for zero-packet-loss high-throughput TCP transmission is a sublinear function of the number of TCP connections 相似文献
30.
RK Dhiman AK Seth S Jain YK Chawla JB Dilawari 《Canadian Metallurgical Quarterly》1998,43(6):1311-1316
Results of eight multicenter, randomized, placebo-controlled, double-blind, parallel-group studies were pooled to assess the efficacy of the angiotensin II-receptor blocker irbesartan over the dose range of 1 to 900 mg. A total of 2955 adults with a seated diastolic blood pressure of 95 to 110 mm Hg were randomized to treatment with oral irbesartan once daily or placebo for 6 to 8 weeks. Office blood pressure was measured at trough (24+/-3 hours after the last dose) and peak (3+/-1 hours after the last dose) by mercury sphygmomanometry. Demographic characteristics (mean blood pressure; 151/101 mm Hg; mean age, 54 years; 63% male; and 82% white) were similar across all dose groups. After the groups were pooled, antihypertensive efficacy was assessed by therapeutic response (trough seated diastolic blood pressure <90 mm Hg or a reduction from baseline of > or = 10 mm Hg) and by modeling of the maximum reductions in trough and peak seated diastolic and systolic blood pressure. Antihypertensive effects increased with increasing doses and reached a plateau at > or = 300 mg. Irbesartan 150 mg provided placebo-subtracted reductions in trough seated systolic and diastolic blood pressure of approximately 8 and approximately 5 mm Hg, respectively, with 56% of patients displaying a favorable response. In conclusion, irbesartan provides clinically significant blood pressure lowering, with a clear relationship between (log) dose and antihypertensive effect. 相似文献