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Modified beat segmentation for DTW based ECG compression
(2015-01-26)
Chompusri, Yotaka
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Dejhan, Kobchai
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Yimman, Surapun
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Charbkaew, Noppadol
The proposed ECG compression method presents the new beat segmentation algorithm. Because this proposed compression method uses the residual difference between original ECG signal beat and the reference ECG beat, the ECG signal must be separated into each beat before doing the compression process. That is the duty of beat segmentation process. Therefore, this process is important step of the selective Mapping Technique ECG compression method. The main goal of this work is to design the beat segmentation algorithm which is the most suitable for this compression method. And this proposed beat segmentation algorithm is designed to replace the complicated operation algorithm. Consequently, this proposed beat segmentation algorithm uses only simple operation such as accumulation and shift operation. And moreover, the decision rule is not complicated as the previous method. The test results show that more than half of tested signals return higher compression ratio (CR). In addition, almost quarter of tested signals have better performance of percent root mean square difference (PRD). Therefore this is the alternative method for the best comparing selection.
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Uroflowmetry recording design
(2015-01-26)
Dejhan, Rodjarin Boontawan Kobchai
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Yimman, Surapun
This research presents the design and construction of a rotating-disc uroflowmetry machine which reduces the energy that collides with the disc, displays results on a Smartphone, and is able to record data. The machine consists of direct current motor, rotating disc, current sensor circuit, filter circuit and processor. The machine works by having a patient's urine directed onto the rotating disc causing change in the current received by the motor. This current can be used to calculate urine volume and flow rate which, in turn, can be used to detect urine abnormalities in patients with urinary tract related diseases. The accuracy of the results from the uroflowmetry machine is tested by a comparison with Torricelli's Law of fluid flow. The results from the comparison showed the uroflowmetry machine to be accurate and efficient for used in practical.
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The estimation of GFR and ERPF using adaptive edge-based active contour for the segmentation of structures in dynamic renal scintigraphy
(2015-01-01)
Suapang, Piyamas
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Dejhan, Kobchai
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Yimman, Surapun
Dynamic renal scintigraphy is usually applied for the estimation of GFR and ERPF. The clearance of 98mTc-DTPA and 99mTc-MAGS were the relatively index of GFR and ERPF in the clinical evaluation of patients with acute and chronic renal failure using camera-based methods. In camera-based methods it is necessary to manually delineate ROIs for 99Tc-DTPA and 99m Tc-MAG3 calculation. The requirement may reduce the convenience and reliability of estimating GFR and ERPF from dynamic renal scintigraphy. This paper proposes the estimation of GFR and ERPF using adaptive edge-based active contour for the segmentation of structures in dynamic renal scintigraphy. The salient feature of proposed method is based on combining three other external force. First, the adaptive elastic parameter has been developed to automatically adjust the rigidity of the snake during its evolution towards an image contour. Second, the adaptive balloon force has been implemented to increase the GVF snake's captured range and convergence speed. Finally, a dynamic GVF force is introduced to provide an efficient evolution stop mechanism. Preliminary segmentation results demonstrate the potential of proposed method and are visually judged to be acceptable for clinical use in comparison with the original GVF snake method and manual segmentation by experts. Furthermore, the mean of estimating GFR and ERPF with the proposed method are successfully predicted and do not differ from APEX-XPERT program at the 5% level of significance.
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Mother wavelet selecting method for selective mapping technique ECG compression
(2012-10-02)
Chompusri, Yotaka
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Dejhan, Kobchai
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Yimman, Surapun
The electrocardiogram compression method presented in this research processes the residual signal which is the difference between the original signal and the reference signal. The residual signal is transformed to wavelet domain and then the redundant information is eliminated in wavelet domain. The selection of mother wavelet is one of main factor to maintain the important data in wavelet domain. The difference type of mother wavelet has its own shape and its own characteristic. Therefore this affects to the performance of compression. This work compares the efficiency of compression algorithm by using difference type of Mother Wavelet. The test shows that no mother wavelet which is the best for all ECG. Thereby, reducing the time consuming for selection the proper mother wavelet, the Best of Four Method is introduced. This algorithm uses four types of mother wavelet to be competitors, 'db1', 'db2', 'db9' and 'bior2.4'. The result shows that the selected mother wavelet types have the good performance on overall tested signals. Moreover, the 'db1' mother wavelet has the best performance on more than a half of all signals. © 2012 IEEE.
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Mathematical model of audiogram with second order recursive system
(2011-12-01)
Jongsataporn, Thitaphan
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Yimman, Surapun
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Praesomboon, Sukanya
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Dejhan, Kobchai
This research presents a new design of mathematical model of audiogram by using the second order recursive all-pass filter and least square approximation technique. The initial step is to design the system function of second order all-pass filter that have the pole-zero angle corresponds with the minimum and maximum amplitude of audiogram. After that, using the least square approximation technique to find the distance of pole and zero between the origin. For the appropriate zero position used least square technique. The magnitude response of propose design was simulated by MATLAB software, the simulation result have show that this method could perform be similar to the audiogram. © 2011 IEEE.
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Novel amplitude compensation for digital signal processing system using minimum phase filter
(2011-12-01)
Praesomboon, Sukanya
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Dejhan, Kobchai
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Yimman, Surapun
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Phromlikhit, Chanchai
This paper proposes minimum phase filter design and applications. The property of a minimum phase filter is having the poles and zeros inside the unit circle. The initial step is to design a minimum phase filter to obtain the specified analog of the reconstruction low pass filter, convert to digital filter using the approximate of derivative and inverse system and next the system of minimum phase filter could be implemented by output function software of digital signal processing system. The experimental result of this proposed method can also be used to compensate for attenuation of the output amplitude obtained from the reconstruction filter at high frequency of digital signal processing system. © 2011 IEEE.
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Minimum phase filter design for reconstruction filter compensation
(2010-12-01)
Yimman, Surapun
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Praesomboon, Sukanya
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Dejhan, Kobchai
This paper proposes minimum phase filter design and its applications. Which the properties of the minimum phase filter have the poles and zeros inside unit circle. The design step of the minimum phase filter, design the analog low-pass filter as reconstructions filter or output filter for digital signal processing system. The reconstruction filter is used as smoothing function for the output signal utilizing approximate derivative method and inverse transformation. The results show that the proposed method can be used to compensate attenuation of the output amplitude obtained from the reconstruction filter (for high frequency of digital signal processing system).
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Sensorless speed control of DC servo motor using Kalman filter
(2009-12-01)
Praesomboon, Sukanya
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Athaphaisal, Santi
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Yimman, Surapun
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Boontawan, Rodjarin
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Dejhan, Kobchai
This research aims to study speed sensorless DC motor control using Kalman filter. Kalman filter considers the DC motor mathematical model. The model will start from a continuous state space into a discrete state space form. Inputs of the system are the armature voltage and the armature current with noises. The output of the system is the estimated speed. Kalman filter is used to estimate the speed without noise interference. The result from the estimated speed will be compared with the reference speed and the speed error will be used by the controller to control the linear amplifier. The final output is the constant speed of the DC motor. Even though the load of the DC motor changed the speed of the DC motor remains constant under the control. The experiment shows that Kalman filter can reject the noise from the system and can estimate the speed of the DC motor with a high accuracy. The estimated speed will be feedback to control the system for constant speed. ©2009 IEEE.
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Design and implementation of novel impedance measurement using digital sine-wave oscillator with optimum phase and amplitude
(2009-12-01)
Praesomboon, Sukanya
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Jongsataporn, Thitaphan
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Yimman, Surapun
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Cheevasuvit, Fusak
This paper proposed the AC bridge circuit, which can be used to measure unidentified impedance of the system. The AC bridge circuit takes the advance of both a digital sine-wave oscillator, which can promptly adjust the phase of generated signals, and a successive approximation technique, which can profoundly search for the unknown impedance. Therefore, the optimum phase and the suitable amplitude can be immediately determined for the AC bridge circuit. In this study, the unknown impedance were calculated by the AC bridge circuit at these following frequencies 50Hz, 100Hz, 300Hz, 500Hz, 750Hz and 1kHz. When compared with the LCR meter (Agilent 4284A), the result of the measured impedance from the AC bridge circuit has revealed the impedance with estimate 1% average error, which suggested that AC bridge circuit is a perfectly innovation method for identifying the unknown impedance. © 2009 SICE.
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Symmetric IIR notch filter design using pole position displacement
(2009-01-01)
Srisangngam, Pichet
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Mongkudvisut, Paolo
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Yimman, Surapun
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Dejhan, Kobchai
This research paper presents the design of symmetrical infinite impulse response (IIR) notch filter using pole position displacement. The technique of modifying the pole-zero placements has been used in order to ensure the symmetrical of the pass-band and transition-band gain. This technique was quantitative and treated by making some meaningful approximations with a set of relatively simple design equations. From the simulation, the design examples have shown the performance of the proposed method effectively.

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