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81.
In a recent work, we demonstrated the usefulness of the Hilbert transform in identifying the in-plane rotation angle between two objects. Here we use the Hilbert-wavelet bases instead of the Hilbert transform in the determination of the exact angle of rotation. We describe the design of the two-dimensional Hilbert-wavelet filter based on the spectral-factorization method to generate a Hilbert-transform pair of orthogonal wavelet bases. We compare the relative performance of the Hilbert transform and the Hilbert wavelet to identify both in-plane and out-of-plane rotation angles. We demonstrate that the Hilbert wavelet offers better rotation-angle determination than the Hilbert transform. We present correlation based rotated and scaled object identification and tracking using Hilbert or Hilbert-wavelet transformed infrared image sequences. We also demonstrate reduced data handling and improved tracking of distorted objects using the Hilbert-wavelet transform. 相似文献
82.
For radiation exposures below 100 mGy, the dosimetric signal in tooth enamel is too small to be measured by using the traditional dose reconstruction procedure. This is because low amplitude zero-added-dose signal can not be identified in an EPR spectrometer. A technique is presented wherein, zero-added-dose signal. when amplified by a proper known dose, can be measured in the EPR spectrometer. Mathematically, the accidental dose x is modified by a known amount of exposure, y (large enough so that the signal is now visible), and total exposure becomes x' = x + y, which is the modified-zero-added dose. The exposure x' is then quantified using the conventional backward extrapolation method and the accidental dose can be measured. In a laboratory controlled experiment, the feasibility of dose reconstruction in the 100 mGy range has been demonstrated. This may enable measurements of dose even due to suspected low exposure in tooth enamel. 相似文献
83.
Mohamed Sahli Christine Millot Claude Roques-Carmes Chantal Khan Malek 《Microsystem Technologies》2009,15(6):827-835
Numerical modelling of the deformation of a polymer using the finite elements method in axisymetrical mode was performed using the LsDyna® software to describe the filling of micro-cavities during the forming process of the material using the hot embossing. These simulations firstly allow verifying whether the chosen forming process conditions promote or not an optimized filling of the superficial cavities in order to achieve precise replicas which best reproduce the superficial topography of the mould. The simulations were carried out to evaluate the filling of the cavities taking into account the mechanical behaviour of the selected polymer into the model. Moreover, these models were developed to verify the effect of the distribution of the mould cavities on their filling. The influence of the mobility of non deformable rigid plates on the filling of the cavities represents an auxiliary variable. In the approach presented, the compression plates are assumed to be parallel and non deformable, whereas the polymer disk follows a rubbery behaviour around a temperature equal to 140°C. Globally the modelling results are satisfactory for they are rather close to the experimental observations conducted. In summary, the effect of the normal stress as also the distribution of micro-cavities at the mould surface seem to prevail in the case of the forming process by hot embossing. 相似文献
84.
Spatial sensitivity analysis of multi-criteria weights in GIS-based land suitability evaluation 总被引:3,自引:0,他引:3
With growing interest in extending GIS to support multi-criteria decision-making (MCDM) methods, enhancing GIS-based MCDM with sensitivity analysis (SA) procedures is crucial to understand the model behavior and its limitations. This paper presents a novel approach of examining multi-criteria weight sensitivity of a GIS-based MCDM model. It explores the dependency of model output on the weights of input parameters, identifying criteria that are especially sensitive to weight changes and to show the impacts of changing criteria weights on the model outcomes in spatial dimension. A methodology was developed to perform simulations where the weights associated with all criteria used for suitability modelling were varied one-at-a-time (OAT) to investigate their relative impacts on the final evaluation results. A tool which incorporates the OAT method with the Analytical Hierarchy Process (AHP) within the ArcGIS environment was implemented. It permits a range of user defined simulations to be performed to quantitatively evaluate model dynamic changes, measures the stability of results with respect to the variation of different parameter weights, and displays spatial change dynamics. A case study of irrigated cropland suitability assessment addressing the application of the new GIS-based AHP-SA tool is described. It demonstrates that the tool is spatial, simple and flexible. 相似文献
85.
86.
Transitional-cell carcinoma is the dominant histological type of malignant tumors of the urinary bladder. There is limited information on risk factors for non-transitional-cell carcinoma (NTCC) of the bladder. We used data from 9 case-control studies on bladder cancer from 6 European countries to examine the association between NTCC, tobacco smoking and occupation. Information on 146 cases diagnosed with NTCC were matched by age, gender and study center to 727 non-cancer population or hospital controls and also with 722 transitional-cell-bladder-cancer controls. Lifetime smoking and occupational history were evaluated. A statistically significant excess risk for NTCC was observed for current smoking [odds ratio (OR) = 3.61, 95% confidence interval (CI) 2.08-6.28]. The risk increased with higher tobacco consumption (OR for highest tertile of pack-years = 7.01, 95% CI 3.60-13.66). The risks were higher for squamous-cell carcinomas than for other types of NTCC. Among major occupational groups, a significant excess risk was seen for field-crop and vegetable-farm workers (OR = 2.06, 95% CI 1.03-4.10). These results indicate that NTCC of the bladder is associated with smoking and specific occupations. The risk pattern seems to differ, in part, from that observed for transitional-cell carcinoma of the bladder. 相似文献
87.
Eakalak Khan Stacey King Roger W. Babcock Jr Michael K. Stenstrom 《Canadian Metallurgical Quarterly》1999,125(6):514-521
The inocula requirements and other experimental conditions for the biodegradable dissolved organic carbon (BDOC) procedure have been investigated and optimized to facilitate its use as a routine parameter for characterizing treatment plant performance. Initial inocula of unfiltered secondary effluent, commercial biochemical oxygen demand seed, mixed-liquor suspended solids (MLSS), and incubation temperatures of 20 and 37°C were examined using standard solutions of known DOC, treatment plant effluents, and ozonated treatment plant effluents. Among all inocula tested, MLSS provides the fastest BDOC exertion rate. It is possible to measure BDOC within five days using a larger volume of MLSS inoculum. The results from this research may be used to support the development of a standard BDOC method for water quality assessment. 相似文献
88.
Khan M.J. Manolatou C. Shanhui Fan Villeneuve P.R. Haus H.A. Joannopoulos J.D. 《Quantum Electronics, IEEE Journal of》1999,35(10):1451-1460
Time-dependent mode-coupling theory is used to analyze a type of resonant add/drop filter based on the excitation of degenerate symmetric and antisymmetric modes. Flat-top transfer functions are achieved with higher order filters that utilize multiple resonator pairs, designed to satisfy the degeneracy conditions. The resulting analytic expressions lead to an equivalent circuit and the transfer characteristics of the filter are related to standard L-C circuit designs 相似文献
89.
90.
A thermal vacuum evaporation system has been used to deposit zinc telluride (ZnTe) thin film on glass substrate in order to investigate the structural, morphological, optoelectronic and electrical properties of the deposited film. The deposited film has been characterised by X-ray diffraction (XRD), atomic force microscopy (AFM), and UV-VIS-NIR spectrophotometer. The polycrystalline and cubic structure of the sample has been confirmed by XRD. The order parameter(s), which determines the crystallinity and good environmental stability of the sample, has been obtained for the peak (1 1 1) to peak (2 0 0) and is found to be 0.83. The XRD patterns and Bragg’s law have been examined to determine the microstructural parameters (lattice parameter, inter-planar spacing, crystallite size, number of crystallites per unit area, strain, dislocation density) of the investigated film. Optical properties (transmittance, absorbance, refractive index, absorption coefficient, extinction coefficient, optical density) of ZnTe thin film were extensively studied in incident photon energy range of 0.5–3.5 eV, where direct optical transition has been obtained with a band gap of 2.63 eV. The surface morphology of the evaporated ZnTe thin film has been checked by AFM. 相似文献