This paper is concerned with the robustness of digital control of continuous plants using general... more This paper is concerned with the robustness of digital control of continuous plants using generalized sample hold functions. Using the frequency domain technique, the authors relate several previous results on this issue within a unified framework, give a quantitative stability analysis of the closed-loop system under different plant model perturbations, and clarify the advantages and disadvantages of this class of
The 3dimensional (3D) volume imaging in magnetic resonanceimaging (MRI) enables encoding in frequ... more The 3dimensional (3D) volume imaging in magnetic resonanceimaging (MRI) enables encoding in frequency, phaseand partition directions in k-space. To increase scan speed, subsampling of multiple-coil k-space data is applied. The imagereconstruction problem from subsampled 3D k-space datais non-convex due to the coupling between image and sensitivityprofile of coils. In this paper, it is shown that the magnitudeof 3D image is constrained in a convex hull and thus canbe solved by a two-step convex optimization procedure. Comparedwith other methods, this method directly processes 3Dk-space data without using sensitivity profile of coils. Phantomand in vivo data are used to test the proposed method, resulting in improved reconstructed image with lower meansquared error.
[Objective] To identify the etiological characteristics and diagnostic significance of hand,foot ... more [Objective] To identify the etiological characteristics and diagnostic significance of hand,foot and mouth disease(HFMD) in Baoshan District of Shanghai by data collected from 2009 to 2011.[Methods]Specimens of throat swabs,anal swabs or faeces and herpes fluids of patients with HFMD were collected from March 2009 to December 2011 to detect nucleic acid of enterovirus 71(EV71),coxsackievirus A16(CoxA16) and other enterovirus.[Results]From 2009 to 2011,the total positive enterovirus rates of all samples were 59.00%,72.44% and 79.00% respectively.The positive rate of EV71 in the severe or fatal cases was 90.91%,significantly higher than those of the general cases(χ2=45.97,P0.001) and the clustered cases(χ2=56.85,P 0.001).The positive rates of enterovirus in throat swabs,anal swabs or faeces,herpes fluids and pharyngeal aspirates were 68.02%,86.67%,71.43%,and 25.00% respectively.The coincidence rate of throat swabs and anal swabs or faeces was 83.53%;and that of throat swabs and herpes was 100.00%.There was a significant difference in the positive rates of nucleic acid between specimens collected 0-4days and 5-10days after onset(79.73% versus 45.61%,χ2=30.91,P0.001).[Conclusion]The main pathogens that caused HFMD in Baoshan District from 2009-2011 were EV71 and CoxA16.The detection rates increased year by year with varied dominant pathogens for each year.Severe or fatal HFMD cases were mainly caused by EV71 in this area.Throat swabs,anal swabs or faeces,and herpes fluids show a high diagnostic value on HFMD monitoring.Collecting HFMD specimens within 4 days after onset is proposed for HFMD diagnosis.
Computational Intelligence for Modelling, Control and Automation, 2001
Spindle breakage during hot steel rolling is a long standing problem encountered in an Australian... more Spindle breakage during hot steel rolling is a long standing problem encountered in an Australian steel plant. Mechanical fault analysis reveals that the possible causes of the problem can be narrowed down to the high spindle torque generated by the mechanical impact when a bar enters the roll bite. This paper uses system identification technique to establish quantitative models which relate spindle torque to the difference between mill speed and bar entry speed. Simulation study shows that by reducing the speed difference, the torque amplification factor (TAF) can be controlled at the manageable level and the spindle torque can be minimized. The result of online experiment base on this concept has been encouraging to date.
Incorporation of parallel imaging technique in dynamic magnetic resonance imaging process acceler... more Incorporation of parallel imaging technique in dynamic magnetic resonance imaging process accelerates significantly the imaging speed. The acceleration is achieved by acquiring the k-space data sparsely in each frame. To unwrap the aliased images caused by the k-space under-sampling, the reconstruction algorithms need the local sensitivity variation, the sensitivity map, of the receiving coils. Current estimation methods are unable to provide the true sensitivity map, and the calibration errors in the estimated sensitivity map can dramatically increase the image artifacts. This paper introduces a novel two-dimensional k-t modeling approach to improve the estimation of sensitivity map. A 2D model is fitted to each k-t plane and is updated for each estimated data point. The model is used to estimate the unacquired k-space data in each frame. A full k-t plane is composed using the estimated and acquired datasets and is used to obtain improved estimation of sensitivity map. Experiments on real dynamic parallel MRI data demonstrate that the proposed method significantly improve the quality of reconstructed MR images.
... Zhaolin Chen 1,2,5 , Leigh Johnston 1,2 , Nathan Faggian 1,3 , Mike Kean 4 , Jingxin Zhang 5 ... more ... Zhaolin Chen 1,2,5 , Leigh Johnston 1,2 , Nathan Faggian 1,3 , Mike Kean 4 , Jingxin Zhang 5 and Gary Egan 1,3 1 Neuroimaging Group, Howard Florey Institute. ... The relatively long imaging time of MRI is a drawback compared with other imaging modali-ties, however. ...
This paper is concerned with the robustness of digital control of continuous plants using general... more This paper is concerned with the robustness of digital control of continuous plants using generalized sample hold functions. Using the frequency domain technique, the authors relate several previous results on this issue within a unified framework, give a quantitative stability analysis of the closed-loop system under different plant model perturbations, and clarify the advantages and disadvantages of this class of
The 3dimensional (3D) volume imaging in magnetic resonanceimaging (MRI) enables encoding in frequ... more The 3dimensional (3D) volume imaging in magnetic resonanceimaging (MRI) enables encoding in frequency, phaseand partition directions in k-space. To increase scan speed, subsampling of multiple-coil k-space data is applied. The imagereconstruction problem from subsampled 3D k-space datais non-convex due to the coupling between image and sensitivityprofile of coils. In this paper, it is shown that the magnitudeof 3D image is constrained in a convex hull and thus canbe solved by a two-step convex optimization procedure. Comparedwith other methods, this method directly processes 3Dk-space data without using sensitivity profile of coils. Phantomand in vivo data are used to test the proposed method, resulting in improved reconstructed image with lower meansquared error.
[Objective] To identify the etiological characteristics and diagnostic significance of hand,foot ... more [Objective] To identify the etiological characteristics and diagnostic significance of hand,foot and mouth disease(HFMD) in Baoshan District of Shanghai by data collected from 2009 to 2011.[Methods]Specimens of throat swabs,anal swabs or faeces and herpes fluids of patients with HFMD were collected from March 2009 to December 2011 to detect nucleic acid of enterovirus 71(EV71),coxsackievirus A16(CoxA16) and other enterovirus.[Results]From 2009 to 2011,the total positive enterovirus rates of all samples were 59.00%,72.44% and 79.00% respectively.The positive rate of EV71 in the severe or fatal cases was 90.91%,significantly higher than those of the general cases(χ2=45.97,P0.001) and the clustered cases(χ2=56.85,P 0.001).The positive rates of enterovirus in throat swabs,anal swabs or faeces,herpes fluids and pharyngeal aspirates were 68.02%,86.67%,71.43%,and 25.00% respectively.The coincidence rate of throat swabs and anal swabs or faeces was 83.53%;and that of throat swabs and herpes was 100.00%.There was a significant difference in the positive rates of nucleic acid between specimens collected 0-4days and 5-10days after onset(79.73% versus 45.61%,χ2=30.91,P0.001).[Conclusion]The main pathogens that caused HFMD in Baoshan District from 2009-2011 were EV71 and CoxA16.The detection rates increased year by year with varied dominant pathogens for each year.Severe or fatal HFMD cases were mainly caused by EV71 in this area.Throat swabs,anal swabs or faeces,and herpes fluids show a high diagnostic value on HFMD monitoring.Collecting HFMD specimens within 4 days after onset is proposed for HFMD diagnosis.
Computational Intelligence for Modelling, Control and Automation, 2001
Spindle breakage during hot steel rolling is a long standing problem encountered in an Australian... more Spindle breakage during hot steel rolling is a long standing problem encountered in an Australian steel plant. Mechanical fault analysis reveals that the possible causes of the problem can be narrowed down to the high spindle torque generated by the mechanical impact when a bar enters the roll bite. This paper uses system identification technique to establish quantitative models which relate spindle torque to the difference between mill speed and bar entry speed. Simulation study shows that by reducing the speed difference, the torque amplification factor (TAF) can be controlled at the manageable level and the spindle torque can be minimized. The result of online experiment base on this concept has been encouraging to date.
Incorporation of parallel imaging technique in dynamic magnetic resonance imaging process acceler... more Incorporation of parallel imaging technique in dynamic magnetic resonance imaging process accelerates significantly the imaging speed. The acceleration is achieved by acquiring the k-space data sparsely in each frame. To unwrap the aliased images caused by the k-space under-sampling, the reconstruction algorithms need the local sensitivity variation, the sensitivity map, of the receiving coils. Current estimation methods are unable to provide the true sensitivity map, and the calibration errors in the estimated sensitivity map can dramatically increase the image artifacts. This paper introduces a novel two-dimensional k-t modeling approach to improve the estimation of sensitivity map. A 2D model is fitted to each k-t plane and is updated for each estimated data point. The model is used to estimate the unacquired k-space data in each frame. A full k-t plane is composed using the estimated and acquired datasets and is used to obtain improved estimation of sensitivity map. Experiments on real dynamic parallel MRI data demonstrate that the proposed method significantly improve the quality of reconstructed MR images.
... Zhaolin Chen 1,2,5 , Leigh Johnston 1,2 , Nathan Faggian 1,3 , Mike Kean 4 , Jingxin Zhang 5 ... more ... Zhaolin Chen 1,2,5 , Leigh Johnston 1,2 , Nathan Faggian 1,3 , Mike Kean 4 , Jingxin Zhang 5 and Gary Egan 1,3 1 Neuroimaging Group, Howard Florey Institute. ... The relatively long imaging time of MRI is a drawback compared with other imaging modali-ties, however. ...
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