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911.
912.
913.
Annick Valibouze 《Journal of Symbolic Computation》2011,46(4):396-405
This article proposes an efficient and simple algebraic method of computation of a Gröbner basis generating the alternating galoisian ideal of a univariate separable polynomial. We named this method “the descent of the Vandermonde determinants”. 相似文献
914.
Tao LiuAuthor Vitae Boxiong WangAuthor Vitae 《Sensors and actuators. A, Physical》2011,171(2):186-190
Intersection technology plays a key role in long-distance horizontal directional drilling (HDD). Magnetic ranging technology is an effective way to realize the intersection. A three-dimensional magnetic field model suitable for the cylindrical magnet connected with drilling bit was established. New formulae of magnetic induction intensity were deduced from the fundamental formulae to suit to the new magnetic ranging method. Based on the new formulae, a curve fitting model was established to complete the ranging. The whole process is simple and effective. The result of the experiment proved the feasibility of the new method and the accuracy is high enough for HDD. 相似文献
915.
Mihaela Carp Raluca Müller Loredana Draghiciu Rodica Voicu Mihai DanilaAuthor vitae 《Sensors and actuators. A, Physical》2011,171(1):26-33
Ferrous chloride has a variety of applications such as a reducing flocculation agent in waste-water treatment, especially for wastes containing chromate, in the laboratory synthesis of iron complexes and it is employed as a reducing agent in many organic syntheses. The device used for experiment was fabricated on the silicon wafer as support for two electrodes in a SU8 polymer microchannel with an inlet, for the injection of aqueous solution of ferrous chloride, and two outlets, for the two by-products of separated solutions. The various parameters of the device were measured by White Light Interferometer (WLI) and Scanning Electron Microscopy (SEM). The magnetic field created by applying different types of potential between two electrodes determined ferrous chloride to separate in ferrous oxide and chlorine (in gaseous form). If a protein is added in this solution we have the possibility to immobilize the protein on the iron particles and on the channel area. The electrical results were collected using a semiconductor system analyzer Keithley and were examined subsequently. The Fe complexes deposited on the electrodes were characterized by XRD analyses. 相似文献
916.
Yunjie ChenAuthor Vitae Jianwei ZhangAuthor VitaeArabinda MishraAuthor Vitae Jianwei YangAuthor Vitae 《Neurocomputing》2011,74(17):3520-3530
Intensity inhomogeneity causes considerable difficulty in the quantitative analysis of magnetic resonance (MR) images. Thus bias field estimation is a necessary pre-processing step before quantitative analysis of MR data. This paper presents a variational level set approach for bias correction and segmentation for images with intensity inhomogeneities. Our method is based on the observation that local intensity variations in relatively smaller regions are separable, despite the inseparability of the whole image. In the beginning we define a function for clustering the image pixels in a smaller neighborhood. The cluster centers in this objective function have a multiplicative factor that estimates the bias within the neighborhood. Generally the local intensity variations are described by the Gaussian distributions with different means and variances. In this work the objective functions are integrated over the entire domain with local Gaussian distribution of fitting energy, ultimately analyzing the data with a level set framework. Our method is able to capture bias of quite general profiles. Moreover, our model can also distinguish regions with similar intensity distribution with different variances. The proposed method has been rigorously validated with images acquired on variety of imaging modalities with promising results. 相似文献
917.
918.
基于TMS320DM642麦克风阵列声源定位系统 总被引:1,自引:0,他引:1
麦克风声源定位是利用麦克风阵列拾取语音信号,并用数字信号处理技术对其进行分析和处理的声源定位技术.在麦克风阵列声源定位中,语音信号端点的拾取是重要的环节.语音端点检测是对接收到的信号利用端点检测算法分析,以确认麦克风阵列中语音信号到达的端点;并利用麦克风阵列中各麦克风接收到的语音信号的端点的先后,计算出麦克风阵列接收的... 相似文献
919.
现代结构普遍大量使用铁磁性钢材料作为承载构件,其受力状态直接关系到结构整体的安全性。由于应力对钢材料磁特征参量的影响比较显著,故在分析了基本原理的前提下,设计了一种管筒式电磁应力传感器。采用有限元仿真技术FLUX软件检验磁路设计的合理性,并提出了实验与仿真相结合的方法对传感器输出电压进行标定。通过实验与仿真计算结果对比,验证了该种方法的正确性,为该种应力检测传感器提供了一种高效的标定方法,使其更加具有市场价值。 相似文献
920.
基于指针映射集的动态内存故障测试方法研究 总被引:2,自引:0,他引:2
动态内存故障在使用指针的程序中是普遍存在的,采用动态测试方法进行测试难以准确定位故障源.而现有的静态分析方法主要存在漏报和误报过多的情况.针对这些问题,提出了指针映射代数系统的概念,全面地反映了指针与内存之间的映射关系,并给出了面向不同故障的指针映射集的构造规则,以此为基础建立了动态内存故障模型.通过指针映射集和故障模型,可以自动检测内存释放异常、内存泄露和空指针引用等动态内存故障,提高了测试效率.在分析过程中,还综合应用了控制流图和路径条件,提高了测试结果的精度.实验结果表明,该方法能够有效检测动态内存故障,而且出于规则定义较为全面,漏报和误报率也较低. 相似文献