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911.
A full-field Digital Image Correlation (DIC) method with integrated Kriging regression is presented in this article. The displacement field is formulated as a best linear unbiased model that includes the correlations between all the locations in the Region of Interest (RoI). A global error factor is employed to extend conventional Kriging interpolation to quantify displacement errors of the control points. An updating strategy for the self-adaptive control grid is developed on the basis of the Mean Squared Error (MSE) determined from the Kriging model. Kriging DIC is shown to outperform several other full-field DIC methods when using open-access experimental data. Numerical examples are used to demonstrate the robustness of Kriging DIC to different choices of initial control points and to speckle pattern variability. Finally Kriging DIC is tested on an experimental example. 相似文献
912.
为综合航电仿真系统和工程任务需求设计实现了一种通用武器仿真系统。采用综合式的系统架构,1553B总线和离散量I/O信号采用分立式,数字仿真模块采用联合式,共同实现武器系统的仿真,减少了系统硬件资源的消耗;使用USB总线作为计算机控制、通信总线,解决了设备即插即用和热插拔的问题。提出了系统总体设计、硬件实现、软件配置和工作流程,给出了系统硬件的框架结构、软件架构,对系统的驱动、编码解码、接口控制文件(ICD,Interface Control Document)类型和人机交互界面进行了讨论。 相似文献
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Tôrres AR Lyra Wda S de Andrade SI Andrade RA da Silva EC Araújo MC Gaião Eda N 《Talanta》2011,84(3):601-606
This work proposes the use of digital image-based method for determination of total acidity in red wines by means of acid-base titration without using an external indicator or any pre-treatment of the sample. Digital images present the colour of the emergent radiation which is complementary to the radiation absorbed by anthocyanines present in wines. Anthocyanines change colour depending on the pH of the medium, and from the variation of colour in the images obtained during titration, the end point can be localized with accuracy and precision. RGB-based values were employed to build titration curves, and end points were localized by second derivative curves. The official method recommends potentiometric titration with a NaOH standard solution, and sample dilution until the pH reaches 8.2-8.4. In order to illustrate the feasibility of the proposed method, titrations of ten red wines were carried out. Results were compared with the reference method, and no statistically significant difference was observed between the results by applying the paired t-test at the 95% confidence level. The proposed method yielded more precise results than the official method. This is due to the trivariate nature of the measurements (RGB), associated with digital images. 相似文献
916.
The digital pre-distortion (DPD) signal processing is an effective way to mitigate the power amplifier (PA) nonlinearity effect. For communication systems containing DPD and PA, it is difficult to acquire performance metrics closed-forms for any DPD architecture since there was no mathematical expression for each DPD coefficient. Usually, researchers look for more efficient DPD algorithms for DPD coefficients (compared to the existing ones) in terms of computational complexity, delay, power consumption, etc. Consequently, the performance is evaluated through intensive simulation. In this paper, we show how one can exploit the results of our recent work to mathematically model the indirect learning architecture (ILA) DPD and efficiently derive important measures in communication systems, e.g. normalized mean square error (NMSE), achievable rate, and signal-to-noise plus distortion ratio (SNDR). The author would like to clarify that this work might be the first one to provide closed-form analysis for DPD systems. We think the provided framework/analysis will open the door to other researchers/engineers to plug their own assumptions and derive the performance metrics. The derived expressions of the performance metrics (NMSE, SNDR, and achievable rate) are validated through Monte Carlo simulations. We also derive a closed-form expression for the achievable rate bound for the transmit chain. Moreover, we analytically study the effect of the thermal noise and the quantization noise, in the analog-digital conversion (ADC) process, on the NMSE and achievable rate. The analytical expressions are validated through numerical simulations. 相似文献
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Md. Mosarraf Hossain Dalip Singh Mehta Chandra Shakher 《Optics & Laser Technology》2008,40(1):120-128
An optical hologram contains substantially more information than necessary for some specific applications. Practical methodology of handling huge information contents in these holograms for such applications is cumbersome. In this paper, a method of information reduction, which aims at efficient storage and transmission of holograms, is investigated using digital composite holography in lensless Fourier transform configuration. The maximum information reduction factor obtained in our experiment is 105. The advantages/disadvantages of this method over an earlier method used in optical holography [Lin LH. A method of hologram information reduction by spatial frequency sampling. Appl Opt 1968;7:545] are also discussed. 相似文献
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920.
This paper presents a feasibility study to assess whether digital speckle pattern interferometry could be used as a possible technique to investigate the adhesive performance of coatings. The approach is based on the measurement of the deflections produced by a pre-notched coated specimen subjected to a four-point bending test. When the bending load is increased, a delamination between the coating and the substrate is propagated with its length depending on the adhesion strength. Experiments carried out with specimens having simulated delaminations confirm that digital speckle pattern interferometry can be used to estimate the delamination length. 相似文献