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991.
Vladan Popovic Kerem Seyid Abdulkadir Akin Ömer Cogal Hossein Afshari Alexandre Schmid Yusuf Leblebici 《Journal of Signal Processing Systems》2014,76(2):169-184
Panoptic is a custom spherical light field camera used as a polydioptric system where imagers are distributed over a hemispherical surface, each having its own vision of the surroundings and a distinct focal plane. The spherical light field camera records light information from any direction around its center. This paper revises previously developed Nearest Neighbor and Linear blending techniques. Novel Gaussian blending and Restricted Gaussian blending techniques for vision reconstruction of a virtual observer located inside the spherical geometry are presented. These new blending techniques improve the output quality of the reconstructed image with respect to the ordinary stitching techniques and simpler image blending algorithms. A comparison of the developed blending algorithms is also given in this paper. A hardware architecture based on Field Programmable Gate Arrays (FPGA) enabling the real-time implementation of the blending algorithms is presented, along with the imaging results and resource utilization comparison. A recorded omnidirectional video is attached as a supplementary material. 相似文献
992.
Shirin Hajeb Mohammad Alipour Hossein Rabbani Mohammadreza Akhlaghi 《Signal, Image and Video Processing》2014,8(2):205-222
In order to achieve early detection of diabetic retinopathy (DR) for the sake of preventing from blindness, regular screening using retinal photography is necessary. Abnormalities of DR do not have uniform distribution over the retina. Certain types of abnormalities usually occur in specific areas on the retina. The distance between lesions, such as micro-aneurysms, and the foveal avascular zone (FAZ) is a useful feature for later analysis and grading of DR. In this paper, a new fully automatic system is presented to find the location of FAZ in fundus fluorescein angiogram photographs. The method is based on two procedures: digital curvelet transform (DCUT) and morphological operations. Firstly, end points of vessels are detected based on vessel segmentation using DCUT. By connecting these points in the selected region of interest, FAZ region is extracted. Secondly, vessels are subtracted from the retinal image, and morphological dilatation and erosion are applied on the resulted image. By choosing an appropriate threshold, FAZ region is detected. The final FAZ region is extracted by performing logical AND between two segmented FAZ. Our experiments show that the system achieves, respectively, the specificity and sensitivity of (>98 and >96 %) for normal stage, for mild/moderate non-proliferative DR (NPDR) (>98, and >95 %) and for Sever NPDR + PDR (>97 and >93 %). 相似文献
993.
A highly efficient method for the aminolysis of epoxides in the presence of a catalytic amount of Fe-MCM-41 is reported. An important advantage of this catalyst is the ease of separating it from the reaction mixture, as well as the fact that it could be recycled a number of times. 相似文献
994.
995.
Hossein M. V. Samani Jamal M. V. Samani Mohammad Shaiannejad 《Canadian Metallurgical Quarterly》2003,129(6):448-454
In this paper a two-dimensional (2D) model for flow through rockfill dams is presented and its results have been compared to 1D model. The model is based on the 2D continuity equation. In the model, an exponential relationship between Reynolds number (R) and Darcy-Weisbach coefficient (f) is suggested and combined with the continuity equation. Coefficients of this relationship are estimated by using real data and a nonlinear optimization technique. Introducing inflow hydrograph to the reservoir and rockfill characteristics as input data and utilizing the above model the outflow hydrograph can be determined. The model has been calibrated and verified using real data. The results of the numerical solution have been shown to be more reliable than the 1D model. To demonstrate the model sensitivity to different parameters, a parametric sensitivity analysis has been conducted. Finally, a comparison between the steady- and unsteady-state results is introduced. 相似文献
996.
997.
Hossein Zia Polireddy Dondeti Thomas E. Needham 《Particulate Science and Technology》1997,15(3):273-301
In this study, the effect of drug loading on the nasal absorption of insulin was determined. Human insulin was loaded into different drug carriers by two methods: supercritical fluid processing and freeze-drying. The powder formulations were characterized and then evaluated after nasal administration to alloxan induced diabetic rabbits at a dose of 5U/kg and 7.5U/kg. The blood glucose levels and serum insulin levels were monitored for five hours after administration of insulin formulations. The drug carriers evaluated were: ammonium glycyrrhizinate (AG), polyacrylic acid (PAA), cross-linked polyacrylic acid (CPAA), polyethylene oxide (PEO) and chitosan (CHTN).
Nasal administration of AG infused with insulin by carbon dioxide resulted in absolute bioavailability of 9.81% as compared to 2.86% observed with same powder loaded with insulin by freeze-drying. 8.05% bioavailability was obtained with PAA powder loaded with insulin by carbon dioxide as compared to much lower absorption seen with freeze-dried formulation. Similarly a two fold increase in absolute bioavailability was observed when carbon dioxide infused CPAA powder formulation was compared to the lyophilized powder. Nasal administration of PEO and CHTN loaded with insulin by carbon dioxide resulted in bioavailabilities of 1.55% and 1. 18% respectively.
The drug-loading process seems to have a significant effect on nasal absorption of insulin. The powders loaded with insulin by carbon dioxide infusion resulted in significantly higher absorption. The exact mechanism is still not known and a possible explanation for increased absorption may be due to improved stability of insulin in carbon dioxide infused formulations. Among the powders evaluated, polyacrylic acid and ammonium glycyrrhizinate prepared by carbon dioxide infusion as drug-loading method seem to offer good potential for development of nasal powder dosage forms for insulin. 相似文献
Nasal administration of AG infused with insulin by carbon dioxide resulted in absolute bioavailability of 9.81% as compared to 2.86% observed with same powder loaded with insulin by freeze-drying. 8.05% bioavailability was obtained with PAA powder loaded with insulin by carbon dioxide as compared to much lower absorption seen with freeze-dried formulation. Similarly a two fold increase in absolute bioavailability was observed when carbon dioxide infused CPAA powder formulation was compared to the lyophilized powder. Nasal administration of PEO and CHTN loaded with insulin by carbon dioxide resulted in bioavailabilities of 1.55% and 1. 18% respectively.
The drug-loading process seems to have a significant effect on nasal absorption of insulin. The powders loaded with insulin by carbon dioxide infusion resulted in significantly higher absorption. The exact mechanism is still not known and a possible explanation for increased absorption may be due to improved stability of insulin in carbon dioxide infused formulations. Among the powders evaluated, polyacrylic acid and ammonium glycyrrhizinate prepared by carbon dioxide infusion as drug-loading method seem to offer good potential for development of nasal powder dosage forms for insulin. 相似文献
998.
This article shows that the interaction between the crude oil and the product market is not a symmetric phenomenon. A $1.00 change in the price of crude will change the price of the product by only $0.51 (in the short run), while a $1.00 change in the price of refined product will cause a $1.03 change in the price of crude (again, in the short run). The product market is much more sensitive to excess supply than the crude market. Excess supply in the product market will not only depress the price of refined oil, but will also lower the price of crude, with a more significant proportion. At present, the international oil market attempts to avoid the consequences of excess supply in the product market by some sort of subjective coordination of refining capacity utilization. The expected market, however, may change the picture for everyone in the industry — refiners, crude producers and OPEC. 相似文献
999.
Hossein Eshraghi Marijan Dravinski 《International journal for numerical methods in engineering》1991,31(5):1009-1026
Scattering of elastic plane waves by three dimensional non-axisymmetric multiple dipping layers embedded in an elastic half-space is investigated by using a boundary method. The dipping layer is subjected to incident Rayleigh waves and oblique incident SH, SV and P waves. For the steady state problem, spherical wave functions are used to express the unkown scattered field. These functions satisfy the equation of motion and radiation conditions at infinity but they do not satisfy the stress free boundary conditions on the surface of the half-space. The boundary and continuity conditions are imposed locally in the least-square sense at points on the layer interfaces and on the surface of the half-space. The transient response is constructed from the steady state solution by using Fourier synthesis. Numerical results are presented for both steady state and transient problems. Steady state problems include solutions for two non-axisymmetric dipping layers in the form of a prolate. Transient responses are presented for one and two dipping layer models subjected to incident wave signals in the shape of a Ricker wavelet. It is shown that change in azimuthal orientation of the incident wave may significantly change the surface response of the dipping layer. For the transient problem, response comparison of one and two dipping layers indicates that the addition of an extra layer may also completely change the response characteristics of the alluvium. In particular, the delay in arrival of much larger amplitude surface waves by two dipping layers in comparison with other geometrically compatible models demonstrates the importance of the detailed three dimensional modelling of layered irregularities. 相似文献
1000.
Wohlwill Joachim F.; Nasar Jack L.; DeJoy David M.; Foruzani Hossein H. 《Canadian Metallurgical Quarterly》1976,61(1):67
Compared the effects of noise under active task involvement as opposed to passive exposure, using 80 undergraduate Ss who were assigned to 1 of 4 conditions representing 2 * 2 combinations of task vs no task and noise vs quiet. Performance on a dial-monitoring task was unaffected by noise. Ratings of interest and tenseness were significantly higher under the task condition; tenseness was also higher under noise. On a posttest of resistance to frustration, both noise groups, regardless of task condition, showed a smaller degree of persistence on insoluble puzzles than the no-noise groups. Results suggest that aftereffects of noise are not dependent on the power of noise to disrupt task performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献