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Delayed control of haemorrhage or blood loss has been recognised as a major contributor to preventable trauma deaths, but early detection of internal bleeding is difficult due to unreliability of heart rate (HR) and blood pressure (BP) as markers of volume status. This thesis explores a novel method of early blood loss detection using a noninvasive finger photoplethysmographic (PPG) pulse oximetry waveform that is normally utilised in pulse oximeters for estimating arterial oxygen saturation. Graded head-up tilt (n = 13) and blood donation (n = 43) in human volunteers were selected as experimental models of mild to moderate blood loss. From the tilt study, a novel method for automatically detecting left ventricular ejection time (LVET) from the finger PPG waveform has been developed and verified by comparison with the LVET measured from aortic flow velocity. PPG waveform derived LVET (LVETp) and pulse transit time (PTT) were strongly correlated with aortic LVET and pre-ejection period respectively (median r = 0.954 and 0.964) and with the decrease in central blood volume indicated by the sine of the tilt angle (median r = -0.985 and 0.938), outperforming R-R interval (RRI) and BP in detecting mild central hypovolaemia. In the blood donation study, progressive blood loss was characterised by falling LVETp and rising PTT (p < 0.01). A new way of identifying haemorrhagic phases by monitoring changes and trends in LVETp, PTT and RRI has been proposed based on the results from the two studies. The utility of frequency spectrum analysis of PPG waveform variability (PPGV) in characterising blood loss has also been examined. A new technique of PPGV analysis by computing the coherence-weighted cross-spectrum has been proposed. It has been shown that the spectral measures of finger PPGV exhibited significant changes (p < 0.01) with blood donation and were mildly correlated with systemic vascular resistance in intensive care unit patients (r from 0.53 to 0.59, p < 0.0001), therefore may be useful for identification of different haemorrhagic phases. In conclusion, this thesis has established finger PPG waveform as a potentially useful noninvasive tool for early detection of blood loss.

Delayed control of haemorrhage or blood loss has been recognised as a major contributor to preventable trauma deaths, but early detection of internal bleeding is difficult due to unreliability of heart rate (HR) and blood pressure (BP) as markers of volume status. This thesis explores a novel method of early blood loss detection using a noninvasive finger photoplethysmographic (PPG) pulse oximetry waveform that is normally utilised in pulse oximeters for estimating arterial oxygen saturation. Graded head-up tilt (n = 13) and blood donation (n = 43) in human volunteers were selected as experimental models of mild to moderate blood loss. From the tilt study, a novel method for automatically detecting left ventricular ejection time (LVET) from the finger PPG waveform has been developed and verified by comparison with the LVET measured from aortic flow velocity. PPG waveform derived LVET (LVETp) and pulse transit time (PTT) were strongly correlated with aortic LVET and pre-ejection period respectively (median r = 0.954 and 0.964) and with the decrease in central blood volume indicated by the sine of the tilt angle (median r = -0.985 and 0.938), outperforming R-R interval (RRI) and BP in detecting mild central hypovolaemia. In the blood donation study, progressive blood loss was characterised by falling LVETp and rising PTT (p < 0.01). A new way of identifying haemorrhagic phases by monitoring changes and trends in LVETp, PTT and RRI has been proposed based on the results from the two studies. The utility of frequency spectrum analysis of PPG waveform variability (PPGV) in characterising blood loss has also been examined. A new technique of PPGV analysis by computing the coherence-weighted cross-spectrum has been proposed. It has been shown that the spectral measures of finger PPGV exhibited significant changes (p < 0.01) with blood donation and were mildly correlated with systemic vascular resistance in intensive care unit patients (r from 0.53 to 0.59, p < 0.0001), therefore may be useful for identification of different haemorrhagic phases. In conclusion, this thesis has established finger PPG waveform as a potentially useful noninvasive tool for early detection of blood loss.

Monitoring stress in real-time, in a non-laboratory environment can be benecial in several applications. One of these, which have been the motivation for this thesis, is to to perform this measurement during Attention decit hyperactivity disorder (ADHD) diagnosis. Monitoring several physiological responses to internal or external stimuli in a single soft-real-time system is nota solution widely used in an application like this. The thesis starts by studying several stress related responses in detail. Sensors for all of the responses are not implemented nor is it possible toimplement in to the desired system. After the study is was decided to implement two measurement modules. The first a Photo-plethysmogrophy (PPG) measurement module to measure heart rate and also estimate breathing. This module is prepared for estimating arterial blood oxygen levels but the calculation or verification have not been done. The second is Skin Conductance (SC) measurement module and in to both ofthese add a temperature sensor to measure the temperature of the skin. Time constraints limit the SC module to only be presented in theory. The PPG module on the other hand have been realisedin a prototype. This prototype performs the measurement in transmissive mode on the left earlobe, which leaves the hands free and it does not affect the hearing on that ear. The prototype giveout acceptable signal quality when good contact with the measurement site is achieved. The signalinterpretation, such as performing the signal analysis to count the beats per minute, is outside thescope of this thesis and will therefore not be presented but the signals can be seen in figures. / Att mäta stress i realtid i verkliga situationer kan vara fördelaktigt för flera applikationer. Det som har legat som grund för denna uppsats är att kunna mäta stress under ADHD diagnostisering. Genom att kombinera de vanliga testerna med stressnivåer hos patienten hoppas man kunna utveckla nya metoder för diagnostisering. Att mäta fera parametrar samtidigt i realtid är inte något ofta utförs idag. För att komma igång har fera kroppsliga funktioner som påverkas på olika sätt av stress studerats. Alla dessa funktioner kan inte inkluderas i det system som önskas konstrueras antingen på grund av systemets karaktär eller på grund tidsbrist. Efter att undersökningen var klar beslutades det att konstruera två moduler. Den första använder en mätteknik som kallas PPG och används för att mäta hjärtfrekvens, även andningsfrekvensen estimeras och modulen är förberedd för att estimera blodsyre nivåa men signalbehandling och validering för detta är inte gjord. Den andra modulen mäter resistans i huden. I dessa moduler lades även till en temperatur sensor för att mäta hudtemperaturen. Tidsbrist har gjort att endast en av dem två modulerna kunnat realiserats. Den som realiserat är PPG modulen och modulen för hudresistans presenteras endast teoretiskt. PPG modulen genomför matningen med en transmissiv teknik på vänster öra och ger ut en acceptabel signal kvalité om sensorn får bra kontakt. Arbetet är avgränsat och inkluderar inte signalanalysen av signalen däremot visualiseras signalen i figurer.

A low cost Heart Beat Monitoring device (HBMD) for detecting heart beat in beats per minute is presented in this thesis. An optical technique called “Photoplethysmography” is utilized by attaching to the base of the finger for monitoring beat to beat pulsation. Two major design issues addressed in this research is to achieve a strong and accurate PPG signal and simultaneously minimizing physiological artefacts and interference. In order to achieve the aim and objectives of the research, this thesis thoroughly explores two new signal conditioning hardware designs. Firstly is the design and fabrication of a low cost reflectance mode PPG heart monitor using parallel port interfacing and secondly are the design and development of a portable transmission mode PPG heart monitor using microcontroller PIC16F84A and PIC16F87. Both PPG heart monitor design is divided into three phases. First is the detection of weak pulses through the fingertip. The PPG signal is then amplified, filtered and digitized by the signal processing unit. Finally the heart rate is calculated, analyzed and displayed on the computer using parallel port interface and on the liquid crystal display using microcontroller PIC16F87. A comprehensive circuit design and analysis work was implemented verified by Proteus VSM circuit simulations and laboratory experiments. Data is presented from the method comparison study in which heart rates measured with the reflectance mode PPG and portable transmission mode PPG heart monitor were compared with those measured with standard techniques on 13 human subjects. Benchmarking tests with approved pulse oximeter and blood pressure monitor Omron M6 reveals that the PPG heart monitor is comparable to those devices in displaying the heart rate. It is also verified through experiments that both PPG heart monitor design fulfill the objectives, including achieving strong and accurate PPG signal, reduction in physiological artefacts and interference and financially low in cost. As the conclusion, the current version of the reflectance mode PPG and portable transmission mode PPG heart monitor successfully measure heart rates fast and reliably in most subjects in different body position. The PPG heart monitor proposed avoid the need to apply electrodes or other sensors in the correct position which directly minimizes the preparation time drastically. This makes the PPG heart monitor more attractive for heart monitoring purpose and its advantage should be explored further.

Chan Ka Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references. / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Objectives --- p.1 / Chapter 1.2 --- Definitions --- p.2 / Chapter 1.2.1 --- Definition of blood pressure --- p.2 / Chapter 1.2.2 --- Definition of hypertension --- p.3 / Chapter 1.3 --- Problems related to hypertension --- p.4 / Chapter 1.4 --- The importance of measuring blood pressure --- p.4 / Chapter 1.4.1 --- Self-measurement of blood pressure --- p.5 / Chapter 1.4.2 --- Ambulatory blood pressure measurement --- p.5 / Chapter 1.5 --- Review of blood pressure measurement techniques --- p.7 / Chapter 1.5.1 --- The invasive method --- p.7 / Chapter 1.5.2 --- Noninvasive methods --- p.8 / Chapter 1.6 --- Review of currently available blood pressure meters --- p.15 / Chapter 1.7 --- Prevalence of hypertension --- p.19 / Chapter 1.7.1 --- Hong Kong --- p.19 / Chapter 1.7.2 --- Worldwide --- p.20 / Chapter 1.8 --- The market for blood pressure meters --- p.21 / Chapter 1.9 --- Organization of the thesis --- p.22 / References --- p.24 / Chapter Chapter 2 --- Measurement of the ECG-PPG interval --- p.30 / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.1.1 --- Pulse transit time (PTT) --- p.30 / Chapter 2.1.2 --- Electrocardiogram (ECG) --- p.36 / Chapter 2.1.2.1 --- Measurement of the ECG signal --- p.37 / Chapter 2.1.3 --- Photoplethysmography (PPG) --- p.38 / Chapter 2.1.3.1 --- Measurement of the PPG signal --- p.41 / Chapter 2.1.4 --- Measurement of blood pressure by ECG-PPG interval --- p.43 / Chapter 2.2 --- Source of errors for measurement of the ECG-PPG interval --- p.44 / Chapter 2.2.1 --- Effects of variability of ECG-PPG intervals --- p.44 / Chapter 2.2.2 --- Effects of bending the arm --- p.49 / Chapter 2.2.3 --- Effects of an external force --- p.54 / Chapter 2.3 --- Conclusion --- p.60 / References --- p.62 / Chapter Chapter 3 --- Cuffless and Noninvasive Measurement of Blood Pressure --- p.68 / Chapter 3.1 --- Introduction --- p.68 / Chapter 3.2 --- Effects of subject-dependent calibration --- p.74 / Chapter 3.3 --- Effects of different time intervals --- p.81 / Chapter 3.4 --- The impact of using different Q-P intervals --- p.96 / Chapter 3.5 --- Real-time measurement of blood pressure --- p.104 / Chapter 3.6 --- Conclusion --- p.108 / References --- p.110 / Chapter Chapter 4 --- Motion Artifact Reduction from PPG Recordings in Ambulatory Blood Pressure Measurement --- p.114 / Chapter 4.1 --- Introduction --- p.114 / Chapter 4.2 --- Previous works --- p.115 / Chapter 4.3 --- Theory --- p.116 / Chapter 4.3.1 --- The adaptive filter --- p.117 / Chapter 4.3.2 --- Variation of step-size parameters --- p.119 / Chapter 4.3.3 --- Effects of filter length --- p.120 / Chapter 4.4 --- Experiment --- p.121 / Chapter 4.5 --- Results --- p.123 / Chapter 4.6 --- Discussion --- p.131 / Chapter 4.7 --- Conclusion --- p.133 / References --- p.135 / Chapter Chapter 5 --- Measurement of Blood Pressure using the PPG signal --- p.138 / Chapter 5.1 --- Introduction --- p.138 / Chapter 5.2 --- Theory --- p.138 / Chapter 5.3 --- Experiment --- p.142 / Chapter 5.3.1 --- Multiple linear regression (MLR) --- p.142 / Chapter 5.3.2 --- Artificial neural networks (ANNs) --- p.146 / Chapter 5.3.3 --- Results --- p.149 / Chapter 5.3.4 --- Discussion --- p.152 / Chapter 5.4 --- The implementation of the Q-P interval --- p.153 / Chapter 5.4.1 --- Results --- p.154 / Chapter 5.4.2 --- Discussion --- p.156 / Chapter 5.5 --- Conclusion --- p.157 / References --- p.158 / Chapter Chapter 6 --- Conclusion and Future Studies --- p.160 / Chapter 6.1 --- Major contributions --- p.160 / Chapter 6.2 --- Future studies --- p.162 / References --- p.165 / Appendix I --- p.166

By far the biggest injury risk faced by people with late onset dementia is a serious fall. Commercial fall detectors are available which automatically alert a call centre or carer if they detect a fall. They use accelerometers to look for the kinematics of a fall but this method is unreliable and the frequent false alarms must be cancelled by the wearer. This is inappropriate for someone with dementia. This thesis examines how a wrist-worn fall detector better suited to someone with dementia might be built. It reviews what other sensors could be used alongside accelerometers, and whether looking for the physiological effects of falling might be beneficial. It concludes that the pulse provides a source of data and describes three empirical trials to examine whether the body pose can be determined from the pulse waveform. A small convenience sample proved the viability of the concept, followed by a larger study to investigate it further, and finally a trial in people of the same age group as late onset dementia sufferers. Producing a technically better device is not sufficient, as it must also be usable by the people it is intended for. The thesis describes two qualitative studies which use carers to define, and then evaluate, a conceptual fall detector suitable for people with moderate or severe dementia which fits underneath a wrist watch. The thesis argues that wearable fall detectors should utilise physiological data to complement kinematic data. It demonstrates the practicality of a novel technique for determining body position using the pulse waveform, and finally concludes that it would be possible to build the conceptual fall detector utilising this technique.

Lee Chi Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 112-121). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Objectives --- p.1 / Chapter 1.2 --- Blood Pressure --- p.2 / Chapter 1.3 --- Hypertension --- p.3 / Chapter 1.3.1 --- Definition of Hypertension --- p.3 / Chapter 1.3.2 --- Causes and Symptoms of Hypertension --- p.3 / Chapter 1.3.3 --- Complication of Hypertension --- p.4 / Chapter 1.3.4 --- Prevalence of Hypertension --- p.4 / Chapter 1.4 --- Blood Pressure Measurement --- p.5 / Chapter 1.4.1 --- History --- p.5 / Chapter 1.4.2 --- Techniques and Methods --- p.7 / Chapter 1.4.3 --- Current Devices --- p.13 / Chapter 1.5 --- Organization of the Thesis --- p.16 / Chapter Chapter 2 --- Theory --- p.18 / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- Blood Rheology --- p.18 / Chapter 2.2.1 --- Blood Composition --- p.18 / Chapter 2.2.2 --- Flow Properties of Blood --- p.19 / Chapter 2.2.3 --- Blood Vessels --- p.21 / Chapter 2.3 --- Principle of the PTT-Based Blood Pressure Measurement --- p.22 / Chapter 2.3.1 --- Wave Propagation in Blood Vessels --- p.22 / Chapter 2.3.2 --- Pulse Transit Time (PTT) --- p.27 / Chapter 2.3.3 --- Blood Pressure Measurement Based on PTT --- p.31 / Chapter 2.4 --- Effects of Temperature on Blood Pressure --- p.34 / Chapter 2.4.1 --- Human Body Temperature Regulation --- p.34 / Chapter 2.4.2 --- Physiological Responses to Decreased Temperature --- p.36 / Chapter 2.4.3 --- Effects of Temperature on Blood Pressure --- p.38 / Chapter 2.5 --- Possible Effects of Temperature on PTT-Based Blood Pressure Measurement --- p.47 / Chapter 2.5.1 --- Windkessel Model --- p.47 / Chapter 2.5.2 --- Phase Velocity --- p.49 / Chapter 2.5.3 --- Effects of temperature on PTT --- p.52 / Chapter 2.5.4 --- Possible Effects of temperature on PTT-based Blood Pressure Measurement --- p.53 / Chapter 2.6 --- Conclusion --- p.54 / Chapter Chapter 3 --- Algorithms in Calculating Pulse Transit Time: Wavelet-Based and Derivative-Based --- p.55 / Chapter 3.1 --- Introduction --- p.55 / Chapter 3.1.1 --- Wavelet Transform (WT) --- p.56 / Chapter 3.1.2 --- Wavelet Transform Modulus Maxima (WTMM) --- p.58 / Chapter 3.2 --- Experiment --- p.60 / Chapter 3.2.1 --- Subjects --- p.60 / Chapter 3.2.2 --- Equipment and Sensors --- p.61 / Chapter 3.2.3 --- Protocol --- p.61 / Chapter 3.3 --- Methods --- p.62 / Chapter 3.3.1 --- Wavelet-Based Algorithm of PTT Calculation --- p.62 / Chapter 3.3.2 --- Derivative-Based Algorithm of PTT Calculation --- p.65 / Chapter 3.3.3 --- PTT-Based Blood Pressure Estimation --- p.67 / Chapter 3.4 --- Results --- p.68 / Chapter 3.5 --- Discussion --- p.70 / Chapter 3.6 --- Conclusion --- p.72 / Chapter Chapter 4 --- Effects of Ambient Temperature on PTT-Based Blood Pressure Estimation --- p.74 / Chapter 4.1 --- Introduction --- p.74 / Chapter 4.2 --- Experiment --- p.74 / Chapter 4.2.1 --- Subjects --- p.74 / Chapter 4.2.2 --- Equipment --- p.75 / Chapter 4.2.3 --- Protocol --- p.76 / Chapter 4.3 --- Methods --- p.77 / Chapter 4.3.1 --- Features of Photoplethysmographic Signals --- p.78 / Chapter 4.3.2 --- Calculation of Pulse Transit Time (PTT) --- p.78 / Chapter 4.4 --- Results --- p.79 / Chapter 4.4.1 --- "Effects of Ambient Temperature on Blood Pressure, Heart Rate and Finger Skin Temperature" --- p.79 / Chapter 4.4.2 --- Effects of Ambient Temperature on the Features of Photoplethysmographic Signals --- p.82 / Chapter 4.4.3 --- Effects of Ambient Temperature on Pulse Transit Time --- p.84 / Chapter 4.4.4 --- PTT-Based Blood Pressure Estimation --- p.85 / Chapter 4.4.6 --- Evaluation of the Modified Equations of the PTT-Based Blood Pressure Measurement Approach --- p.89 / Chapter 4.5 --- Discussion --- p.94 / Chapter 4.6 --- Conclusion --- p.98 / Chapter Chapter 5 --- Effects of Local Temperature on PTT-Based Blood Pressure Estimation --- p.99 / Chapter 5.1 --- Introduction --- p.99 / Chapter 5.2 --- Methods --- p.99 / Chapter 5.3 --- Results --- p.100 / Chapter 5.3.1 --- "Effects of Local Temperature on Blood Pressure, Heart Rate and Finger Skin Temperature" --- p.100 / Chapter 5.3.2 --- Effects of Local Temperature on Pulse Transit Time --- p.102 / Chapter 5.3.3 --- Effects of Local Temperature on the Features of Photoplethysmographic Signal --- p.103 / Chapter 5.3.4 --- Effects of Local Temperature on PTT-Based Blood Pressure Estimation --- p.104 / Chapter 5.4 --- Discussion --- p.105 / Chapter 5.5 --- Conclusion --- p.107 / Chapter Chapter 6 --- Conclusion and Future Study --- p.108 / Chapter 6.1 --- Major Contributions --- p.108 / Chapter 6.2 --- Future Study --- p.110 / References --- p.112 / Chapter Appendix A --- Motion Artifact Reduction from PPG signal Based on a Wavelet Approach --- p.122 / Chapter A.l --- Introduction --- p.122 / Chapter A.1.1 --- Motion Artifact --- p.122 / Chapter A.1.2 --- Stationary Wavelet Transform (SWT) --- p.123 / Chapter A.2 --- Experiment --- p.124 / Chapter A.2.1 --- Subjects --- p.124 / Chapter A.2.2 --- Equipment --- p.124 / Chapter A.2.3 --- Protocol --- p.125 / Chapter A.3 --- Methods --- p.126 / Chapter A.3.1 --- Algorithm --- p.126 / Chapter A.3.2 --- Data Analysis --- p.128 / Chapter A.4 --- Results --- p.129 / Chapter A.5 --- Discussion --- p.131 / Chapter A.6 --- Conclusion --- p.133 / Reference --- p.133 / Appendix B Derivation of the Moens-Korteweg Equation --- p.134 / Reference --- p.136

Gu Yingying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 155-164). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- IPFM Model --- p.1 / Chapter 1.1.1 --- Description of IPFM Model --- p.1 / Chapter 1.1.2 --- Background of IPFM Related Modeling --- p.3 / Chapter 1.2 --- Windkessel Model --- p.8 / Chapter 1.2.1 --- Background of the Windkessel Model --- p.8 / Chapter 1.2.2 --- Windkessel Related Modeling --- p.13 / Chapter 1.3 --- Photoplethysmogram (PPG) --- p.14 / Chapter 1.3.1 --- Principle of PPG --- p.14 / Chapter 1.3.2 --- Characteristics of PPG Signal --- p.16 / Chapter 1.4 --- A Study on the Beat-to-Beat BPV --- p.18 / Chapter 1.5 --- Main Purposes of the Study --- p.19 / Chapter 1.6 --- Organization of the Thesis --- p.20 / Chapter 2 --- Spectral Analysis on the IPFM Process --- p.22 / Chapter 2.1 --- Introduction --- p.22 / Chapter 2.2 --- A Theoretical Study on the Neural Firing Rate Function --- p.23 / Chapter 2.2.1 --- Mathematical Derivation of the Neural Firing Rate --- p.23 / Chapter 2.2.2 --- Spectral Analysis of the IPFM Process --- p.27 / Chapter 2.2.3 --- Reconstruction of Neural Firing Rate through LPF --- p.30 / Chapter 2.3 --- Effects of Neural Dynamics --- p.33 / Chapter 2.4 --- Discussion & Conclusion --- p.35 / Chapter 3 --- A New Model for the Generation of PPG --- p.37 / Chapter 3.1 --- Introduction --- p.37 / Chapter 3.2 --- Principles of PPG --- p.38 / Chapter 3.2.1 --- Relationship between Pressure and Flow --- p.38 / Chapter 3.2.2 --- Peripheral Pressure and Flow Curves --- p.41 / Chapter 3.2.3 --- Generation of PPG signal --- p.43 / Chapter 3.3 --- Model Description --- p.44 / Chapter 3.3.1 --- IPFM model --- p.45 / Chapter 3.3.2 --- Windkessel model --- p.46 / Chapter 3.3.3 --- New Model for the Generation of PPG --- p.49 / Chapter 3.4 --- Simulation --- p.51 / Chapter 3.4.1 --- Generation of ECG --- p.51 / Chapter 3.4.2 --- Generation of PPG --- p.57 / Chapter 3.4.3 --- Effects of the Modulation Depth on the Output --- p.65 / Chapter 3.4.4 --- Effects of Mean Autonomic Tone on HRV --- p.72 / Chapter 3.5 --- Discussion & Conclusion --- p.75 / Chapter 4 --- A Correlation Study on the Beat-to-Beat Features of Photoplethysmographic Signals --- p.80 / Chapter 4.1 --- Introduction --- p.80 / Chapter 4.2 --- Methodology --- p.81 / Chapter 4.2.1 --- Experimental Conditions --- p.81 / Chapter 4.2.2 --- Definition of the Parameters --- p.82 / Chapter 4.3 --- Data Analysis --- p.85 / Chapter 4.3.1 --- At Normal Relaxed State --- p.85 / Chapter 4.3.2 --- At Different Levels of Contacting Force --- p.87 / Chapter 4.3.3 --- At Different Levels of Local Skin Finger Temperature --- p.90 / Chapter 4.3.4 --- At Dynamic State --- p.93 / Chapter 4.3.5 --- Repeatability Study --- p.95 / Chapter 4.3.6 --- Spectral Analysis --- p.96 / Chapter 4.4 --- Discussion --- p.98 / Chapter 5 --- The Estimation of the Beat-to-Beat Blood Pressure Variability --- p.103 / Chapter 5.1 --- Introduction --- p.103 / Chapter 5.2 --- BP Estimation using FY Interval --- p.104 / Chapter 5.2.1 --- Multi-Beat BP Estimation under Different Levels of Contacting Force --- p.104 / Chapter 5.2.2 --- Beat-to-Beat BP Estimation --- p.108 / Chapter 5.2.3 --- Repeatability Study --- p.112 / Chapter 5.3 --- A Study on the Beat-to-Beat BPV --- p.113 / Chapter 5.3.1 --- Background of the Beat-to-Beat BPV --- p.113 / Chapter 5.3.2 --- Analysis of the Beat-to-Beat BPV --- p.115 / Chapter 5.4 --- Improving the PPG Model with the Time-Varying BP --- p.120 / Chapter 5.4.1 --- Modification of the Model --- p.121 / Chapter 5.4.2 --- Simulation --- p.127 / Chapter 5.4.3 --- Application of the PPG Model --- p.132 / Chapter 5.5 --- Discussion & Conclusion --- p.134 / Chapter 6 --- A Novel Biometric Approach --- p.139 / Chapter 6.1 --- Introduction --- p.139 / Chapter 6.2 --- Human Verification by PPG Signal --- p.140 / Chapter 6.2.1 --- Experiment --- p.141 / Chapter 6.2.2 --- Feature Extraction --- p.142 / Chapter 6.2.3 --- Decision-making --- p.143 / Chapter 6.2.4 --- Results --- p.146 / Chapter 6.3 --- Discussion --- p.149 / Chapter 7 --- Conclusions --- p.151 / Chapter 7.1 --- Conclusions of Major Contributions --- p.151 / Chapter 7.2 --- Work to Be Done --- p.154