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171.
N. Hoseini 《Optimization》2018,67(8):1265-1286
172.
173.
Simion Breaz 《Linear and Multilinear Algebra》2018,66(11):2215-2217
We will prove that every endomorphism of a free right R-module of infinite rank can be decomposed as a sum of four endomorphisms which satisfy some fixed polynomial identities. 相似文献
174.
175.
F W Wehrli J R MacFall G H Glover N Grigsby V Haughton J Johanson 《Magnetic resonance imaging》1984,2(1):3-16
In Nuclear Magnetic Resonance (NMR) the image pixel value is governed by at least three major intrinsic parameters: the spin density N (H), the spin-lattice relaxation time T1, and the spin-spin relaxation time T2. The extent to which the signal is weighted toward one or several parameters is related to the history of the spin system preceding detection. On the simplifying, though not generally warranted assumption that the spin density does not vary significantly in soft tissues, relative tissue contrast can be predicted quantitatively provided the relaxation times are known. Signal intensities and contrast were computed on the basis of the Bloch equations and experimentally determined relaxation times as a function of pulse timing parameters and the data compared with those in images recorded at 0.5T field strength. Significant deviations from the equal density hypothesis were found for gray and white substance. Notably partial saturation but also spin echo and inversion-recovery images are not in full accordance with predictions made on the basis of relaxation times alone. 相似文献
176.
In this paper we use the method of images to derive the closed-form formula for the first passage time density of a time-dependent Ornstein–Uhlenbeck process to a parametric class of moving boundaries. The results are then applied to develop a simple, efficient and systematic approximation scheme to compute tight upper and lower bounds of the first passage time density through a fixed boundary. 相似文献
177.
Content-based image retrieval has been an active area of research for more than ten years.Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and classification. In this paper,we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomography (CT) images query.In our experiments,a batch of hepatic CT images containing several types of CT findings are used for the retrieval test.Precision comparison between our scheme and existing methods is presented. 相似文献
178.
Zhenxue Chen Guoyou Wang Jianguo Liu Chengyun Liu 《International Journal of Infrared and Millimeter Waves》2007,28(1):87-97
Detecting small targets in clutter scene and low SNR (Signal Noise Ratio) is an important and challenging problem in infrared
(IR) images. In order to solve this problem, we should do works from two sides: enhancing targets and suppressing background.
Firstly, in this paper, the system utilizes the average absolute difference maximum (AADM) as the dissimilarity measurement
between targets and background region to enhance targets. Secondly, it uses a predictor to suppress the background clutter.
Finally, our approach extracts the interested small target with segment threshold. Experimental results show that the algorithm
proposed has better performance with respect to probability of detection and less computation complexity. It is an effective
small infrared target detection algorithm against complex background. 相似文献
179.
180.
Real-time, continuous-wave terahertz (THz) imaging is demonstrated. A 1.89-THz optically-pumped farinfrared laser is used as the illumination source, and a 124 × 124 element room-temperature pyroelectric camera is adopted as the detector. With this setup, THz images through various wrapping materials are shown. The results show that this imaging system has the potential applications in real-time mail and security inspection. 相似文献