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Liu W.,CAS Shenzhen Institutes of Advanced Technology | Hu C.,CAS Shenzhen Institutes of Advanced Technology | He Q.,CAS Shenzhen Institutes of Advanced Technology | Meng M.Q.-H.,Chinese University of HongKong
2010 IEEE International Conference on Information and Automation, ICIA 2010 | Year: 2010

In order to achieve the goal of high accuracy and low cost in a visual localization system, we present a novel localization method based on four inexpensive video cameras. The method mainly consists of two parts: The "16-points interpolation algorithm" is proposed to enhance the accuracy of 2D coordinates of the detected target on the image plane. Another important aspect is that the Perpendicular Foot Method (PFM) is used to calculate the 3D coordinates of the target. Simulation and real experimental results show that the stability of image coordinates (x, y) is significantly improved by the "16-points interpolation algorithm", and the PFM algorithm is better than the traditional LSM (Least Square Method) algorithm. The localization accuracy of this system can reach 5mm, when the target is moved along with the y axes direction which is perpendicular to the optical axes of CCD cameras. ©2010 IEEE.

Fan Y.,Sun Yat Sen University | Lan L.,Chinese University of HongKong | Zheng L.,Sun Yat Sen University | Ji X.,Sun Yat Sen University | And 4 more authors.
Metabolic Brain Disease | Year: 2015

Hypertension is considered one of the most important controllable risk factors for white matter lesion (WML). Our previous work found that stroke-prone renovascular hypertensive rats (RHRSP) displayed a high rate of WML. This study aimed to investigate the WML in RHRSP from MRI, pathology and behavior. RHRSP model was established by two-kidney, two-clipmethod and kept for 20 weeks. WML was decteted by magnetic resonance imaging (MRI) and loyez staining. Cognition was tested by morris water maze (MWM). Vascular changes were observed by HE staining on brain and carotid sections. Ultrastucture of blood brain barrier (BBB) were observed by transmission electron microscope. Immunofluorescence was used to detect albumin leakage and cell proliferation. T2-weighted MRI scans of RHRSP displayed diffuse, confluent white-matter hyperintensities. Pathological examination of the same rat showed marked vacuoles, disappearence of myelin and nerve fibers in white matter, supporting the neuroimaging findings. Spatial learning and memory impairment were observed in RHRSP. The small arteries in brain exhibited fibrinoid necrosis, hyalinosis and vascular remodeling. BBB disruption and plasma albumin leakage into vascular wall was observed in RHRSP. Increased cell proliferation in subventricular zone was seen in RHRSP. RHRSP demonstrated spontaneous WML and cognitive impairment. Hypertensive small vessel lesions and BBB disruption might paly causative factors for the onset and development of WML. The characteristic features of WML in RHRSP suggested it a valid animal model for WML. © 2015, Springer Science+Business Media New York.

Zhang C.,Nanjing University of Aeronautics and Astronautics | Guo P.,Chinese University of HongKong | Ehmann K.F.,Northwestern University | Li Y.,Nanjing University of Aeronautics and Astronautics
Materials and Manufacturing Processes | Year: 2015

Microgroove, as a form of surface texturing, has a wide array of industrial applications. However, the use of conventional methods to machine microgrooves leads to a number of problems including large burrs, high cutting forces, and poor machining quality. In this paper, ultrasonic elliptical vibration cutting is used to assist microgrooves turning on cylindrical workpiece surfaces. The elliptical locus in the cutting process is generated by a newly designed 2D resonant ultrasonic vibrator. A series of microgrooves cutting experiments without and with the ultrasonic elliptical vibration-assistance is performed to verify the effects of the ultrasonic elliptical vibrations as compared to the ordinary cutting method. The generated cutting forces, burr suppression action, and microgroove surface quality are compared for the two classes of processes. Comparison results show the effectiveness of elliptical vibration-assisted microgroove cutting in reducing cutting forces and improving microgrooves machining quality for difficult-to-cut materials. The results also show that ultrasonic elliptical vibration-assisted cutting improves the microgroove turning process with respect to cutting forces, microgroove surface roughness, and burr formation for difficult-to-cut materials. © Taylor & Francis Group,LsLC.

Wang L.,CAS Shenzhen Institutes of Advanced Technology | Chen H.,CAS Institute of Software | Li S.,CAS Shenzhen Institutes of Advanced Technology | Meng H.M.,CAS Shenzhen Institutes of Advanced Technology | Meng H.M.,Chinese University of HongKong
Speech Communication | Year: 2012

Speech visualization is extended to use animated talking heads for computer assisted pronunciation training. In this paper, we design a data-driven 3D talking head system for articulatory animations with synthesized articulator dynamics at the phoneme level. A database of AG500 EMA-recordings of three-dimensional articulatory movements is proposed to explore the distinctions of producing the sounds. Visual synthesis methods are then investigated, including a phoneme-based articulatory model with a modified blending method. A commonly used HMM-based synthesis is also performed with a Maximum Likelihood Parameter Generation algorithm for smoothing. The 3D articulators are then controlled by synthesized articulatory movements, to illustrate both internal and external motions. Experimental results have shown the performances of visual synthesis methods by root mean square errors. A perception test is then presented to evaluate the 3D animations, where a word identification accuracy is 91.6% among 286 tests, and an average realism score is 3.5 (1 = bad to 5 = excellent). © 2012 Elsevier B.V. All rights reserved.

Li Q.,U.S. Center for Disease Control and Prevention | Dong H.Y.,PATH Beijing Office | Pang Y.,U.S. Center for Disease Control and Prevention | Xia H.,U.S. Center for Disease Control and Prevention | And 8 more authors.
Biomedical and Environmental Sciences | Year: 2015

In order to evaluate the performance of a molecular Hain line probe assay (Hain LPA) for rapid detection of rifampicin and isoniazid resistance of Mycobacterium tuberculosis in China, 1612 smear positive patients were consecutively enrolled in this study. Smear positive sputum specimens were collected for Hain LPA and conventional drug susceptibility testing (DST). The sensitivity and specificity of Hain LPA were analyzed by using conventional DST as golden reference. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for rifampicin resistance detection were 88.33%, 97.66%, 81.54%, and 98.62%, respectively. The sensitivity, specificity, PPV and NPV for isoniazid resistance detection were 80.25%, 98.07%, 87.25%, and 96.78%, respectively. These findings suggested that Hain LPA can be an effective method worthy of broader use in China. © 2015 The Editorial Board of Biomedical and Environmental Sciences.

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