Algorithms ; Noise, Occupational ; Numerical Analysis, Computer-Assisted

In this paper, according to the requirement of the focused sound field measurement, a focused sound field measurement system was established based on the LabVIEW virtual instrument platform. The system can automatically search the focus position of the sound field, and adjust the scanning path according to the size of the focal region. Three-dimensional sound field scanning time reduced from 888 hours in uniform step to 9.25 hours in variable step. The efficiency of the focused sound field measurement was improved. There is a certain deviation between measurement results and theoretical calculation results. Focal plane--6 dB width difference rate was 3.691%, the beam axis--6 dB length differences rate was 12.937%.
Computer Simulation ; Numerical Analysis, Computer-Assisted ; Software ; Sound

QRS complex has its distinct characteristics as compared with other waves in Electrocardiogram (ECG). In this paper is introduced a kind of algorithm to identify the R waves, which combines forward-backward difference algorithm, half-wave width algorithm and R-R interval algorithm. The algorithm is simple and reliable. It is in possession of the ability of anti-interference such as baseline drifting, high P waves or high T waves, and severe high-frequency interference. The average accuracy for identification is higher than 99.5%. The results of the experiment and the analyses are also presented.
Algorithms ; Electrocardiography ; methods ; Humans ; Numerical Analysis, Computer-Assisted ; Signal Processing, Computer-Assisted

Numerical simulation of the thyroxin producing process of a human body is presented to analyze the dynamic and static variation laws of the process. The relationship between the static value of thyroxin and the reaction coefficients of various physiologic chemical reactions upon the producing thyroxin is clarified. The simulation results provided in this paper can be utilized as some reference data for clinical pathogeny analysis of some thyroxin diseases.
Computer Simulation ; Humans ; Mathematics ; Models, Theoretical ; Numerical Analysis, Computer-Assisted ; Thyroid Gland ; secretion ; Thyroxine ; biosynthesis

The function theory of an anesthesia vaporizer was studied and the geometry configuration was measured in this study. The internal gas flow and mixing process in the anesthesia vaporizer were simulated using CFD method. Applying tracking in turbulent flow to stochastic particle, for the droplet of anesthesia drug, the moving track of droplet was traced. Based on the results, the internal gas flow variation, the concentration distribution of anesthesia drug volatilization process and mixing process with gas were ascertained. Numerical simulation results showed that, the diluted gas velocity reduction of internal flow in the anesthesia vaporizer was higher. Because of the anesthesia vaporizer geometry, the mixing process between anesthesia drug vapor and diluting gas was not homogeneous. This also influenced the stability and accuracy of anesthesia drug concentration. The optimization precept of anesthesia vaporizer is ascertained.
Anesthesia, Inhalation ; instrumentation ; Computer Simulation ; Humans ; Imaging, Three-Dimensional ; Nebulizers and Vaporizers ; standards ; Numerical Analysis, Computer-Assisted

There have been insufficient numerical methods for particular description and quantitative evaluation of left ventricular diastolic function in the studies in this area. We therefore have summarized the computational models of the affecting factors for diastolic function from five aspects, i. e. the geometry shape of left ventricular, myocardial stiffness, myocardial viscosity, myocardial relaxation and ventricular interaction respectively. Controlling the sensitive parameters and having a mathematical description on left ventricular diastolic dysfunction can provide numerical methods for clinical diagnosis and quantitative evaluation of the disease.
Computer Simulation ; Diastole ; physiology ; Humans ; Models, Theoretical ; Numerical Analysis, Computer-Assisted ; Ventricular Function, Left ; physiology

In this paper, the structure parameters and the equations to calculate these parameters are presented for the model design of the artificial bio-valve on the basis of heart anatomy, shell theory and the optimal flow of heart valve. No-root bio-valve is designed and manufactured according to the above theoies and technology. Its perfect property has been confirmed by measurement in vitro and clinical application in vivo.
Algorithms ; Computer-Aided Design ; Heart Valve Prosthesis ; Numerical Analysis, Computer-Assisted ; Prosthesis Design ; methods

The registration method based on mutual information is currently a popular technique for the medical image registration, but the computation for the mutual information is complex and the registration speed is slow. In engineering process, a subsampling technique is taken to accelerate the registration speed at the cost of registration accuracy. In this paper a new method based on statistics sample theory is developed, which has both a higher speed and a higher accuracy as compared with the normal subsampling method, and the simulation results confirm the validity of the new method.
Algorithms ; Artifacts ; Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; methods ; Magnetic Resonance Imaging ; methods ; Numerical Analysis, Computer-Assisted

To detect lesions of brain CT automatically, a statistical atlas of attribute vectors (SAAV) was designed and created to describe the multiple features of medical images. By comparing the features of study image with those of SAAV, we successfully detected various kinds of brain lesion. It was demonstrated that the algorithm is effective in detecting various kinds of lesions found on brain CT images. Further studies are needed to make the algorithm more acceptable.
Algorithms ; Brain Diseases ; diagnostic imaging ; Humans ; Image Processing, Computer-Assisted ; Numerical Analysis, Computer-Assisted ; Tomography, X-Ray Computed

The advent of parallel MRI over recent years has prompted a variety of techniques for performing parallel imaging. The main distinguishing feature among these is the specific way of solving the problem of image reconstruction from undersampled multiple-coil data. The clearest distinction in this respect is that between k-space method and image-domain method. The present paper reviews the basic reconstruction approaches, aiming to emphasize the common principles along with actual differences. To this end the treatment starts with an elaboration of the encoding mechanisms and sampling strategies that define the reconstruction task. Based on these considerations, the distinction between k-space and image-domain approaches is given. At the close of this paper are presented discussioins concerning noise propagation and control in parallel imaging and an outlook upon key issues to be addressed in the future.
Algorithms ; Humans ; Image Enhancement ; methods ; Image Interpretation, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; methods ; Numerical Analysis, Computer-Assisted ; instrumentation ; Signal Processing, Computer-Assisted ; instrumentation