The analytical algorithm of program quaternion is studied,aiming at the problem of the arbitrary spacecraft attitude-adjusting *** also provides the analytical constructor method of the program quaternion for any give...
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The analytical algorithm of program quaternion is studied,aiming at the problem of the arbitrary spacecraft attitude-adjusting *** also provides the analytical constructor method of the program quaternion for any given initial quaternion and angle velocity,terminal quaternion and angle *** advantages of this method are as follows:(1)Good *** of the initial and terminal conditions are arbitrary;(2)Simple *** calculation process only involves the simple algebraic operation;(3)Easy to *** using the program quaternion model,the time consumption in the process of spacecraft attitude adjustment and the maximum angular velocity can be optimized *** to the Mathematical simulation results,the program quaternion tracking can be realized by a simple PD control law.
The analysis of the carotid artery wall is of paramount importance in clinical practice. Especially, the intima-media thickness is a risk index for some of the most severe acute cerebrovascular pathologies, hence, an ...
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The analysis of the carotid artery wall is of paramount importance in clinical practice. Especially, the intima-media thickness is a risk index for some of the most severe acute cerebrovascular pathologies, hence, an accurate segmentation of the different layers of the carotid artery is needed. IMT is usually manually measured on longitudinal B-mode ultrasound images. In the past ten years, many computer-based techniques for intima-media thickness measurement have been proposed to overcome the limits of manual segmentation, but almost all of them require a certain degree of user interaction. In this paper we proposed a novel approach for the completely user-independent segmentation of the common carotid artery wall. Our algorithm is designed for the extraction of the intima and media layers of the distal carotid wall in ultrasound images. It is based on integrated approach consisting of common carotid artery region identification, contour initialization with threshold segmentation, intima-lumen segmentation with Snake, and media-adventitia segmentation with GVF-Snake that enables the automated tracing of the carotid walls. The acoustic impedance's difference is employed to locate common carotid artery region. Finally, the characterization of the algorithm in terms of segmentation error was evaluated with a set of 40 common carotid artery ultrasound images and compared to the segmentation traced by a trained operator. Experiments showed that a mean error lower than 1.3 pixel both on the intima and media layers was obtained, which is comparable to that obtained by means of operator dependent techniques.
Reliability and accuracy in personal identification system is a dominant concern to the security world. Biometric has gained much attention in this subject recently. Many types of personal identification systems have ...
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Reliability and accuracy in personal identification system is a dominant concern to the security world. Biometric has gained much attention in this subject recently. Many types of personal identification systems have been developed, and palmprint identification is one of the emerging technologies. This paper presents a novel biometric technique to automatic personal identification system using multispectral palmprint technology. In this method, each of spectrum images are aligned and then used to extract palmprint features using 1D log-Gabor filter. These features are then examined for their individual and combined performances. Finally, the hamming distance is used for matching of palmprint features. The experimental results showed that the proposed method achieve an excellent identification rate and provide more security.
An Echo State Network (ESN) based predictive control method for aircraft system is proposed to increase the flight quality. Aero craft is a nonlinear and time-varying system and its controllers are usually designed by...
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An Echo State Network (ESN) based predictive control method for aircraft system is proposed to increase the flight quality. Aero craft is a nonlinear and time-varying system and its controllers are usually designed by trajectory linearization method. Furthermore, the predictive controller is designed to adjust the current controlled variables by the trend of output to improve the quick responsiveness and traceability. Then, the stability of the system is proved by Lyapunov function. Finally, the numerical simulation results of step-response and attitude tracking illustrate the robustness and effect of the method.
To improve rendered view quality in a 3-D video system, we propose to encode and transmit depth transition data, which represents, for each pixel in a frame, the location in between two existing views where the depth ...
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To improve rendered view quality in a 3-D video system, we propose to encode and transmit depth transition data, which represents, for each pixel in a frame, the location in between two existing views where the depth corresponding to that pixel changes. Given the highly localized and non-linear characteristics of rendered view distortion, it is possible to achieve better coding performance by providing this depth transition data only for subjectively important regions. In this paper, a method to apply the depth transition data to the view rendering procedure is proposed. Experimental results verify that improvements in subjective quality can be achieved by the proposed method.
Stroke and heart attack, which could be led by a kind of cerebrovascular and cardiovascular disease named asatherosclerosis, would seriously cause human morbidity and mortality. And the carotid artery of intima-media ...
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Stroke and heart attack, which could be led by a kind of cerebrovascular and cardiovascular disease named asatherosclerosis, would seriously cause human morbidity and mortality. And the carotid artery of intima-media thickness (IMT) is a key indicator to the disease. With the development of computer assisted diagnosis (CAD) technology, Ultrasound imaging, being real-time, economic, reliable, safe, and now seems to become a standard in vascular assessment methodology especially for the measurement of IMT. This review is an attempt to discuss the clinical relevance of measurements in clinical practice at first, and then followed by the challenges that one has to face when approaching the segmentation of ultrasound images. Secondly, the paper is presentation of common used methods for the IMT segmentation and measurement. An overview of summary and future perspectives is given in conclusion finally.
Small sample space target recognition is a difficult problem in applications because the limited training samples cannot lead to satisfactory recognition accuracy. Combined with novel compression perception theory, we...
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Small sample space target recognition is a difficult problem in applications because the limited training samples cannot lead to satisfactory recognition accuracy. Combined with novel compression perception theory, we propose a new space target recognition method based on compressive sensing. This method avoids the sophisticated image preprocessing and feature extraction process. Firstly, a sparse representation dictionary is constructed according to the training samples. Secondly, the linear measurements of test samples are obtained by measurement matrix. Finally, the classification and recognition are done through solving an optimization problem. Simulation experiment results show that the proposed method has good recognition performance and stability.
This paper proposes an approximated power method to track the signal subspace. Using rank-one update model, the signal subspace can be obtained by finding the least square solutions of two unconstrained weight functio...
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ISBN:
(纸本)9781612847191
This paper proposes an approximated power method to track the signal subspace. Using rank-one update model, the signal subspace can be obtained by finding the least square solutions of two unconstrained weight functions. As introduced in instrumental variable (IV), this bi-iteration algorithm can track signals corrupted by colored noise. Especially the tracking results are orthonormalized to get better performances. Some DOA simulations are provided to illustrate the effectiveness of the proposed method.
Part I of this special issue is devoted to the physical layer, MAC layer, and physical-link cross-layer design technologies of vehicular communications and networks. There are 21 papers in this issue.
Part I of this special issue is devoted to the physical layer, MAC layer, and physical-link cross-layer design technologies of vehicular communications and networks. There are 21 papers in this issue.
Solving the optimal control problem with a free final time, such as suborbital launch vehicle (SLV) trajectory optimization with two control variables and multi-constraints ones based on particle swarm optimization (P...
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Solving the optimal control problem with a free final time, such as suborbital launch vehicle (SLV) trajectory optimization with two control variables and multi-constraints ones based on particle swarm optimization (PSO), the smoothness of control variable can not be satisfied by linear interpolation method. A novel method including some improving strategies based on PSO for trajectory optimization is proposed, named LCPSO which is a kind of Cooperate PSO based on Legendre orthogonal polynomials. An additional control variable is introduced and transcribes the original optimal problem to a problem with fixed final time, and one dimension searching method based on interval analysis is used to optimize the additional control variable. Furthermore, a theorem on how to find the boundaries of the coefficient of polynomials is proved. Compared with basic PSO, LCPSO has traits of lower dimensions and smoother control variable. An example of trajectory optimization shows the effectiveness of the LCPSO algorithm.
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