Bill Diong | Kennesaw State University (original) (raw)

Papers by Bill Diong

In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and int... more In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and integrated with a commercially available ultra-low power boost converter with a turn-on voltage of 0.3V. This circuit was tested, up to a maximum range of 5.5 meters, using log periodic UHF transmit and receive antennas with 28 dBm output power from the transmitter. The boosted voltage of 4.2V at the converter's output can enable a wider range of wireless sensors for Internet-of- Things applications.

2021 ASEE Virtual Annual Conference Content Access, Jul 26, 2021

2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018

In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and int... more In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and integrated with a commercially available ultra-low power boost converter with a turn-on voltage of 0.3V. This circuit was tested, up to a maximum range of 5.5 meters, using log periodic UHF transmit and receive antennas with 28 dBm output power from the transmitter. The boosted voltage of 4.2V at the converter's output can enable a wider range of wireless sensors for Internet-of- Things applications.

2013 ASEE Annual Conference & Exposition Proceedings

This paper proposes the use of a multilayer feedforward neural network to control a multilevel in... more This paper proposes the use of a multilayer feedforward neural network to control a multilevel inverter-based dual-frequency induction heating power supply, plus the use of distributed computing to train that network. The motivation is because the control function mappings from the desired waveform's two modulation indices to its step-angles are not simple closed-form expressions, so using look-up tables to implement

Measurements of the respiratory impedance in humans are a means to help diagnose underdevelopment... more Measurements of the respiratory impedance in humans are a means to help diagnose underdevelopment and/or pathological conditions. Various models of the human respiratory system of varying complexity and fidelity have been developed for study to enable greater specificity of the diagnosis. In this paper, a parametric sensitivity analysis that was performed on the respiratory impedance of four different respiratory system

Conference proceedings, Aug 1, 2007

This paper introduces two new respiratory system models, the Mead-Cw model and the Mead-Cl model,... more This paper introduces two new respiratory system models, the Mead-Cw model and the Mead-Cl model, which are 6-component models that are intermediate in complexity between the well-known 7-component Mead model and the recently proposed 5-component augmented RIC model (derived from the Mead model by eliminating both Cw and Cl). Their modeling errors were compared to the RIC, extended RIC, augmented RIC and Mead models, for component values estimated from IOS data. The two new models yielded lower errors than all the other models, except for the Mead model. However, the Mead-Cl model and the Mead-Cw model also yielded unreasonably large values for Cw and Cl, respectively, which are known disadvantages of the Mead model. Hence the augmented RIC model appears to be the most useful at present for IOS-based computer-aided detection and diagnosis of respiratory disorders.

The Journal of Allergy and Clinical Immunology, Feb 1, 2008

ABSTRACT RATIONALE: Since IOS reactance at 5 Hz (X5) measures small airway bronchodilator respons... more ABSTRACT RATIONALE: Since IOS reactance at 5 Hz (X5) measures small airway bronchodilator responsivity in children with asthma, we analyzed frequency- dependence of IOS resistance (R) and integrated low frequency reactance (AX) in 2-5 year old children with asthma to quantify effects of SABA and LABA on lung mechanics. METHODS: We reanalyzed IOS replicates from existing data reported by Ortiz and Menendez (J of Asthma 2002; 39:531-536), calculating resistance (R) and reactance (X) between 5-35 Hz. We tabulated average R5, R5-R20, and AX from 3-6 IOS replicates free of artifacts at 5, 30, 60, 360 min after albuterol and placebo on two clinic visits; and additionally at 540 min after salmeterol MDI and DPI on two further visits. Results were entered into a respiratory system model to derive peripheral airway resistance (Rp) and compliance (Cp). RESULTS: Significant improvement in IOS indices occurred 5 min postalbuterol, augmented over 60 min, returning towards baseline at 360 min. Significant changes in IOS indices occurred 5 min post-salmeterol and augmented over 6 to 9 hours. Rp decreased and Cp increased after treatment with SABA and LABA but not after placebo. CONCLUSIONS: IOS parameters reflecting small airway mechanics respond in 5 minutes post albuterol and salmeterol in young children. Calculated Rp and Cp decrease and increase respectively after albuterol and salmeterol at 5 minutes and continue for 6-9 hours. IOS low frequency resistance, frequency-dependence of resistance, and integrated low frequency reactance are sensitive measures of lung mechanics responses to SABA and LABA in pre-school children with asthma.

IFMBE proceedings, 2009

Impulse Oscillometry (IOS) provides respiratory resistance, Rrs, and reactance, Xrs, between 3 - ... more Impulse Oscillometry (IOS) provides respiratory resistance, Rrs, and reactance, Xrs, between 3 - 35 (Hz). We measured IOS parameters in 26 randomly selected Anglo children 6-19 years in El Paso TX. An expert pulmonologist classified Rrs and Xrs as: Normal (n = 5 ); Possible Small Airway Impairment, Possible SAI, (n = 4); Definite SAI (n = 6); or Asthma (n = 11). We used the extended RIC (eRIC) and augmented RIC (aRIC) models of the human respiratory system to derive Large (R) and Peripheral (Rp) airway resistance, and small airway compliance, Cp. IOS Rrs and Xrs at selected frequencies reflecting large and peripheral airway function. Model-derived parameters were compared between pre- and post-bronchodilator tests. IOS Xrs at low frequencies (AX) and model-derived Cp were the most sensitive parameters for detecting bronchodilator responses, which were significant in children with SAI and asthma. Model-derived Cp correlated closely with AX. We conclude that response to bronchodilator in children with SAI is sensitively measured by IOS. Electrical equivalent model parameters are as sensitive as primary IOS data in detecting bronchodilator response.

IFMBE proceedings, 2010

Chronic Obstructive Pulmonary Disease (COPD) is an important cause of illness and death. Sensitiv... more Chronic Obstructive Pulmonary Disease (COPD) is an important cause of illness and death. Sensitive assessments of COPD may be obtained by Impulse Oscillometry (IOS) during resting breathing. The respiratory impedance measured by IOS is modeled well by the augmented RIC (aRIC) circuit with parameters R,I,R p ,C p ,C e , representing central airway resistance and inertance, peripheral airway resistance and compliance, and extrathoracic compliance, respectively. IOS measurements (from 5 to 35 Hz) were obtained from ten normal adults and ten adults with varying degrees of COPD. The aRIC parameters were then derived by least-squares-optimal fitting to the IOS data. Using Mann-Whitney tests, the main IOS resistance and reactance parameters (R5, R5-R15, X5) and aRIC model parameters (R,R p ,I,C p ,C e , R p /C p ) were analyzed to determine if the values for normal adults came from the same population as the COPD adults’ values. For IOS R5, R5-R15, X5, the approximating z statistics were -6.47, -6.48, 6.46, respectively. For aRIC R,R p ,I,C p ,C e , R p /C p , the z statistics were -3.04, -4.31, 2.02, 6.34, 1.64, -6.46, respectively. At a 99% confidence level, all of these parameters, except aRIC I and C e , were found to come from different distributions. Furthermore, we calculated the Pearson product-moment-correlation-coefficients between aRIC R,R p ,I,C p ,C e , 1/C p ,R p /C p , and IOS R5, R5-R15, X5, R5-R min , R min . In COPD adults, we found very strong correlations between aRIC R and IOS R min (0.987), R p and X5 (-0.992), 1/C p and R5-R min (0.935), and R p /C p and X5 (-0.962). We conclude that the aRIC model of respiratory impedance is as sensitive as IOS to lung function changes in COPD, and that certain aRIC parameters correlate well to IOS parameters used for clinical assessment of COPD.

IFMBE proceedings, 2010

Impulse Oscillometry (IOS) measurements of respiratory impedance were obtained from young asthmat... more Impulse Oscillometry (IOS) measurements of respiratory impedance were obtained from young asthmatic children pre- and post-bronchodilator (pre- and post-BD). Mead’s model of respiratory impedance was then used to estimate the central inertance (I), central and peripheral resistances (Rc, Rp), and lung, chest wall, bronchial, and extrathoracic compliances (Cl, Cw, Cb, Ce) by least-squares-optimal fitting to the IOS data. This typically produced multiple near-optimal solutions, with estimates ofCl and Cw that varied by 2 to 3 orders of magnitude and were also several orders of magnitude larger than expected physiological values; up to 515,000 L/kPa for Cl, and 81,138 L/kPa for Cw. We then performed constrained optimization of pre-BD data with Cw fixed at 0.50 L/kPa and Cl fixed at 0.38 L/kPa, which yielded averaged least-squares (LS) error 44.1% larger than for unconstrained optimization, while Rc, I, Rp, Cb and Ce changed by an average of 12.5%, 32.2%, 25.1%, 26.7% and 2.6x1011%, relative to unconstrained values; the large change in Ce due to it becoming negligible in about 25% of the results. Next, constrained optimization of post-BD data with Cw = 0.5 L/kPa, Cl = 0.38 L/kPa, resulted in an averaged LS error 39.4% larger than for unconstrained optimization, while Rc, I, Rp, Cb and Ce changed by an average of 1.7x1012%, 23.4%, 29.1%, 36.9% and 3.5x1011%, relative to unconstrained values. Neglecting two results with unphysiologically small Rc reduced the average change in Rc to 19.1% without significantly impacting the average change of the other parameters. Constrained optimization of pre-BD data and then post-BD data with Cw = 0.5 L/kPa, Cl = 0.33 L/kPa, resulted in similar changes to total LS error and remaining parameters. We conclude that the Mead model’s impedance and parameter estimates (except Ce, unimportant in asthma) for young asthmatic children are relatively insensitive to Cl and Cw.

proposed model of the human respiratory system is described and analyzed in this article. Impulse... more proposed model of the human respiratory system is described and analyzed in this article. Impulse oscillometry data were used to obtain parameter estimates for this and four well-known models of the respiratory system in order to gauge its fidelity. Of these five models, the proposed extended Resistance-Inductance- Capacitance (RIC) model ranked in the middle in terms of magnitude of modeling

Biomedical Engineering Online, 2011

The forced oscillation technique offers some advantages over spirometry for assessing pulmonary f... more The forced oscillation technique offers some advantages over spirometry for assessing pulmonary function. It requires only passive patient cooperation; it also provides data in a form, frequency-dependent impedance, which is very amenable to engineering analysis. In particular, the data can be used to obtain parameter estimates for electric circuit-based models of the respiratory system, which can in turn aid the detection and diagnosis of various diseases/pathologies. In this study, we compare the least-squares error performance of the RIC, extended RIC, augmented RIC, augmented RIC+I(p), DuBois, Nagels and Mead models in fitting 3 sets of impedance data. These data were obtained by pseudorandom noise forced oscillation of healthy subjects, mild asthmatics and more severe asthmatics. We found that the aRIC+I(p) and DuBois models yielded the lowest fitting errors (for the healthy subjects group and the 2 asthmatic patient groups, respectively) without also producing unphysiologically large component estimates.

Springer eBooks, 2010

... Insensitive to Mead Model Lung Compliance and Chest Wall Compliance Parameters Bill Diong1, M... more ... Insensitive to Mead Model Lung Compliance and Chest Wall Compliance Parameters Bill Diong1, Michael D. Goldman2, and Homer Nazeran2 1 ... and the Impulse Oscillometry System (IOS)[2] in particular, which requires only the subject's passive KE Herold, WE Bentley, and J ...

SAE Technical Paper Series, 2004

The dynamic behavior of a fuel cell is integral to the overall stability and performance of the p... more The dynamic behavior of a fuel cell is integral to the overall stability and performance of the power system formed by the fuel supply, fuel cell stack, power conditioner and electrical load. But present-day fuel cells have transient (dynamic) responses that are much slower than the responses of the typical power conditioner and load. Therefore, there is significant motivation to identify which fuel cell parameters have greater impact on the cell's transient response so as to facilitate improved designs of such cells. This paper describes the results obtained from a sensitivity analysis performed on an input-output transfer function that is derived from a linear small-signal model of PEM fuel cell dynamics. These provide greater insight into the issue of which physical parameters have the greater impacts on fuel cell dynamic response.

In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and int... more In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and integrated with a commercially available ultra-low power boost converter with a turn-on voltage of 0.3V. This circuit was tested, up to a maximum range of 5.5 meters, using log periodic UHF transmit and receive antennas with 28 dBm output power from the transmitter. The boosted voltage of 4.2V at the converter's output can enable a wider range of wireless sensors for Internet-of- Things applications.

2021 ASEE Virtual Annual Conference Content Access, Jul 26, 2021

2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018

In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and int... more In this paper, a two-stage RF -DC charge pump is designed for impedance matching at 1 GHz and integrated with a commercially available ultra-low power boost converter with a turn-on voltage of 0.3V. This circuit was tested, up to a maximum range of 5.5 meters, using log periodic UHF transmit and receive antennas with 28 dBm output power from the transmitter. The boosted voltage of 4.2V at the converter's output can enable a wider range of wireless sensors for Internet-of- Things applications.

2013 ASEE Annual Conference & Exposition Proceedings

This paper proposes the use of a multilayer feedforward neural network to control a multilevel in... more This paper proposes the use of a multilayer feedforward neural network to control a multilevel inverter-based dual-frequency induction heating power supply, plus the use of distributed computing to train that network. The motivation is because the control function mappings from the desired waveform's two modulation indices to its step-angles are not simple closed-form expressions, so using look-up tables to implement

Measurements of the respiratory impedance in humans are a means to help diagnose underdevelopment... more Measurements of the respiratory impedance in humans are a means to help diagnose underdevelopment and/or pathological conditions. Various models of the human respiratory system of varying complexity and fidelity have been developed for study to enable greater specificity of the diagnosis. In this paper, a parametric sensitivity analysis that was performed on the respiratory impedance of four different respiratory system

Conference proceedings, Aug 1, 2007

This paper introduces two new respiratory system models, the Mead-Cw model and the Mead-Cl model,... more This paper introduces two new respiratory system models, the Mead-Cw model and the Mead-Cl model, which are 6-component models that are intermediate in complexity between the well-known 7-component Mead model and the recently proposed 5-component augmented RIC model (derived from the Mead model by eliminating both Cw and Cl). Their modeling errors were compared to the RIC, extended RIC, augmented RIC and Mead models, for component values estimated from IOS data. The two new models yielded lower errors than all the other models, except for the Mead model. However, the Mead-Cl model and the Mead-Cw model also yielded unreasonably large values for Cw and Cl, respectively, which are known disadvantages of the Mead model. Hence the augmented RIC model appears to be the most useful at present for IOS-based computer-aided detection and diagnosis of respiratory disorders.

The Journal of Allergy and Clinical Immunology, Feb 1, 2008

ABSTRACT RATIONALE: Since IOS reactance at 5 Hz (X5) measures small airway bronchodilator respons... more ABSTRACT RATIONALE: Since IOS reactance at 5 Hz (X5) measures small airway bronchodilator responsivity in children with asthma, we analyzed frequency- dependence of IOS resistance (R) and integrated low frequency reactance (AX) in 2-5 year old children with asthma to quantify effects of SABA and LABA on lung mechanics. METHODS: We reanalyzed IOS replicates from existing data reported by Ortiz and Menendez (J of Asthma 2002; 39:531-536), calculating resistance (R) and reactance (X) between 5-35 Hz. We tabulated average R5, R5-R20, and AX from 3-6 IOS replicates free of artifacts at 5, 30, 60, 360 min after albuterol and placebo on two clinic visits; and additionally at 540 min after salmeterol MDI and DPI on two further visits. Results were entered into a respiratory system model to derive peripheral airway resistance (Rp) and compliance (Cp). RESULTS: Significant improvement in IOS indices occurred 5 min postalbuterol, augmented over 60 min, returning towards baseline at 360 min. Significant changes in IOS indices occurred 5 min post-salmeterol and augmented over 6 to 9 hours. Rp decreased and Cp increased after treatment with SABA and LABA but not after placebo. CONCLUSIONS: IOS parameters reflecting small airway mechanics respond in 5 minutes post albuterol and salmeterol in young children. Calculated Rp and Cp decrease and increase respectively after albuterol and salmeterol at 5 minutes and continue for 6-9 hours. IOS low frequency resistance, frequency-dependence of resistance, and integrated low frequency reactance are sensitive measures of lung mechanics responses to SABA and LABA in pre-school children with asthma.

IFMBE proceedings, 2009

Impulse Oscillometry (IOS) provides respiratory resistance, Rrs, and reactance, Xrs, between 3 - ... more Impulse Oscillometry (IOS) provides respiratory resistance, Rrs, and reactance, Xrs, between 3 - 35 (Hz). We measured IOS parameters in 26 randomly selected Anglo children 6-19 years in El Paso TX. An expert pulmonologist classified Rrs and Xrs as: Normal (n = 5 ); Possible Small Airway Impairment, Possible SAI, (n = 4); Definite SAI (n = 6); or Asthma (n = 11). We used the extended RIC (eRIC) and augmented RIC (aRIC) models of the human respiratory system to derive Large (R) and Peripheral (Rp) airway resistance, and small airway compliance, Cp. IOS Rrs and Xrs at selected frequencies reflecting large and peripheral airway function. Model-derived parameters were compared between pre- and post-bronchodilator tests. IOS Xrs at low frequencies (AX) and model-derived Cp were the most sensitive parameters for detecting bronchodilator responses, which were significant in children with SAI and asthma. Model-derived Cp correlated closely with AX. We conclude that response to bronchodilator in children with SAI is sensitively measured by IOS. Electrical equivalent model parameters are as sensitive as primary IOS data in detecting bronchodilator response.

IFMBE proceedings, 2010

Chronic Obstructive Pulmonary Disease (COPD) is an important cause of illness and death. Sensitiv... more Chronic Obstructive Pulmonary Disease (COPD) is an important cause of illness and death. Sensitive assessments of COPD may be obtained by Impulse Oscillometry (IOS) during resting breathing. The respiratory impedance measured by IOS is modeled well by the augmented RIC (aRIC) circuit with parameters R,I,R p ,C p ,C e , representing central airway resistance and inertance, peripheral airway resistance and compliance, and extrathoracic compliance, respectively. IOS measurements (from 5 to 35 Hz) were obtained from ten normal adults and ten adults with varying degrees of COPD. The aRIC parameters were then derived by least-squares-optimal fitting to the IOS data. Using Mann-Whitney tests, the main IOS resistance and reactance parameters (R5, R5-R15, X5) and aRIC model parameters (R,R p ,I,C p ,C e , R p /C p ) were analyzed to determine if the values for normal adults came from the same population as the COPD adults’ values. For IOS R5, R5-R15, X5, the approximating z statistics were -6.47, -6.48, 6.46, respectively. For aRIC R,R p ,I,C p ,C e , R p /C p , the z statistics were -3.04, -4.31, 2.02, 6.34, 1.64, -6.46, respectively. At a 99% confidence level, all of these parameters, except aRIC I and C e , were found to come from different distributions. Furthermore, we calculated the Pearson product-moment-correlation-coefficients between aRIC R,R p ,I,C p ,C e , 1/C p ,R p /C p , and IOS R5, R5-R15, X5, R5-R min , R min . In COPD adults, we found very strong correlations between aRIC R and IOS R min (0.987), R p and X5 (-0.992), 1/C p and R5-R min (0.935), and R p /C p and X5 (-0.962). We conclude that the aRIC model of respiratory impedance is as sensitive as IOS to lung function changes in COPD, and that certain aRIC parameters correlate well to IOS parameters used for clinical assessment of COPD.

IFMBE proceedings, 2010

Impulse Oscillometry (IOS) measurements of respiratory impedance were obtained from young asthmat... more Impulse Oscillometry (IOS) measurements of respiratory impedance were obtained from young asthmatic children pre- and post-bronchodilator (pre- and post-BD). Mead’s model of respiratory impedance was then used to estimate the central inertance (I), central and peripheral resistances (Rc, Rp), and lung, chest wall, bronchial, and extrathoracic compliances (Cl, Cw, Cb, Ce) by least-squares-optimal fitting to the IOS data. This typically produced multiple near-optimal solutions, with estimates ofCl and Cw that varied by 2 to 3 orders of magnitude and were also several orders of magnitude larger than expected physiological values; up to 515,000 L/kPa for Cl, and 81,138 L/kPa for Cw. We then performed constrained optimization of pre-BD data with Cw fixed at 0.50 L/kPa and Cl fixed at 0.38 L/kPa, which yielded averaged least-squares (LS) error 44.1% larger than for unconstrained optimization, while Rc, I, Rp, Cb and Ce changed by an average of 12.5%, 32.2%, 25.1%, 26.7% and 2.6x1011%, relative to unconstrained values; the large change in Ce due to it becoming negligible in about 25% of the results. Next, constrained optimization of post-BD data with Cw = 0.5 L/kPa, Cl = 0.38 L/kPa, resulted in an averaged LS error 39.4% larger than for unconstrained optimization, while Rc, I, Rp, Cb and Ce changed by an average of 1.7x1012%, 23.4%, 29.1%, 36.9% and 3.5x1011%, relative to unconstrained values. Neglecting two results with unphysiologically small Rc reduced the average change in Rc to 19.1% without significantly impacting the average change of the other parameters. Constrained optimization of pre-BD data and then post-BD data with Cw = 0.5 L/kPa, Cl = 0.33 L/kPa, resulted in similar changes to total LS error and remaining parameters. We conclude that the Mead model’s impedance and parameter estimates (except Ce, unimportant in asthma) for young asthmatic children are relatively insensitive to Cl and Cw.

proposed model of the human respiratory system is described and analyzed in this article. Impulse... more proposed model of the human respiratory system is described and analyzed in this article. Impulse oscillometry data were used to obtain parameter estimates for this and four well-known models of the respiratory system in order to gauge its fidelity. Of these five models, the proposed extended Resistance-Inductance- Capacitance (RIC) model ranked in the middle in terms of magnitude of modeling

Biomedical Engineering Online, 2011

The forced oscillation technique offers some advantages over spirometry for assessing pulmonary f... more The forced oscillation technique offers some advantages over spirometry for assessing pulmonary function. It requires only passive patient cooperation; it also provides data in a form, frequency-dependent impedance, which is very amenable to engineering analysis. In particular, the data can be used to obtain parameter estimates for electric circuit-based models of the respiratory system, which can in turn aid the detection and diagnosis of various diseases/pathologies. In this study, we compare the least-squares error performance of the RIC, extended RIC, augmented RIC, augmented RIC+I(p), DuBois, Nagels and Mead models in fitting 3 sets of impedance data. These data were obtained by pseudorandom noise forced oscillation of healthy subjects, mild asthmatics and more severe asthmatics. We found that the aRIC+I(p) and DuBois models yielded the lowest fitting errors (for the healthy subjects group and the 2 asthmatic patient groups, respectively) without also producing unphysiologically large component estimates.

Springer eBooks, 2010

... Insensitive to Mead Model Lung Compliance and Chest Wall Compliance Parameters Bill Diong1, M... more ... Insensitive to Mead Model Lung Compliance and Chest Wall Compliance Parameters Bill Diong1, Michael D. Goldman2, and Homer Nazeran2 1 ... and the Impulse Oscillometry System (IOS)[2] in particular, which requires only the subject's passive KE Herold, WE Bentley, and J ...

SAE Technical Paper Series, 2004

The dynamic behavior of a fuel cell is integral to the overall stability and performance of the p... more The dynamic behavior of a fuel cell is integral to the overall stability and performance of the power system formed by the fuel supply, fuel cell stack, power conditioner and electrical load. But present-day fuel cells have transient (dynamic) responses that are much slower than the responses of the typical power conditioner and load. Therefore, there is significant motivation to identify which fuel cell parameters have greater impact on the cell's transient response so as to facilitate improved designs of such cells. This paper describes the results obtained from a sensitivity analysis performed on an input-output transfer function that is derived from a linear small-signal model of PEM fuel cell dynamics. These provide greater insight into the issue of which physical parameters have the greater impacts on fuel cell dynamic response.