• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 61
  • 16
  • 15
  • 14
  • 13
  • 7
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 149
  • 149
  • 69
  • 32
  • 18
  • 17
  • 15
  • 15
  • 14
  • 14
  • 13
  • 13
  • 13
  • 11
  • 10
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Cuffless calibration and estimation of continuous arterial blood pressure.

January 2009 (has links)
Gu, Wenbo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references. / Abstract also in Chinese. / Acknowledgment --- p.i / Abstract --- p.ii / 摘要 --- p.iii / List of Figures --- p.vi / List of Tables --- p.vii / List of Abbreviations --- p.viii / Contents --- p.ix / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Arterial blood pressure and its importance --- p.1 / Chapter 1.2. --- Current methods for non-invasive blood pressure measurement --- p.4 / Chapter 1.2.1. --- The auscultatory method (mercury sphygmomanometer) --- p.4 / Chapter 1.2.2. --- The oscillometric method --- p.5 / Chapter 1.2.3. --- The tonometric method --- p.7 / Chapter 1.2.4. --- The volume-clamp method --- p.7 / Chapter 1.3. --- Blood pressure estimation based on pulse arrival time --- p.8 / Chapter 1.4. --- Objectives and structures of this thesis --- p.10 / Chapter 2. --- Hemodynamic models: relationship between PAT and BP --- p.14 / Chapter 2.1. --- The generation of arterial pulsation --- p.14 / Chapter 2.2. --- Pulse wave velocity along the arterial wall --- p.15 / Chapter 2.2.1. --- Moens-Korteweg equation --- p.15 / Chapter 2.2.2. --- Bergel wave velocity --- p.18 / Chapter 2.3. --- Relationship between PWV and BP --- p.19 / Chapter 2.3.1. --- Bramwell-Hill´ةs model --- p.20 / Chapter 2.3.2. --- Volume-pressure relationship --- p.20 / Chapter 2.3.3. --- Hughes' model --- p.22 / Chapter 2.4. --- The theoretical expression of PAT-BP relationship --- p.23 / Chapter 3. --- Estimation and calibration of arterial BP based on PAT --- p.25 / Chapter 3.1. --- PAT measurement --- p.25 / Chapter 3.1.1. --- Principle of ECG measurement --- p.25 / Chapter 3.1.2. --- Principle of PPG measurement --- p.26 / Chapter 3.1.3. --- Calculation of PAT --- p.28 / Chapter 3.2. --- Calibration methods for PAT-BP estimation --- p.29 / Chapter 3.2.1. --- Calibration based on cuff BP readings --- p.30 / Chapter 3.2.2. --- Calibration by hydrostatic pressure changes --- p.31 / Chapter 3.2.3. --- Calibration by multiple regression --- p.33 / Chapter 3.3. --- Model-based calibration with PPG waveform parameters --- p.34 / Chapter 3.3.1. --- Model-based equation with parameters from PPG waveform --- p.34 / Chapter 3.3.2. --- Selection of parameters from PPG waveform --- p.36 / Chapter 4. --- Cuffless calibration approach using PPG waveform parameter for PAT-BP estimation --- p.43 / Chapter 4.1. --- Introduction --- p.43 / Chapter 4.2. --- Experiment I: young group in sitting position including rest and after exercise states --- p.43 / Chapter 4.2.1. --- Experiment protocol --- p.43 / Chapter 4.2.2. --- Data Analysis --- p.44 / Chapter 4.2.3. --- Experiment results --- p.46 / Chapter 4.3. --- Experiment II: over-month observation using wearable device in sitting position --- p.48 / Chapter 4.3.1. --- Body sensor network for blood pressure estimation --- p.49 / Chapter 4.3.2. --- Experiment protocol and data collection --- p.50 / Chapter 4.3.3. --- Experiment results --- p.50 / Chapter 4.4. --- Experiment III: contactless monitoring in supine position --- p.51 / Chapter 4.4.1. --- The design of the contactless system --- p.52 / Chapter 4.4.2. --- Experiment protocol and data collection --- p.53 / Chapter 4.4.3. --- Experiment results --- p.53 / Chapter 4.5. --- Discussion --- p.55 / Chapter 4.5.1. --- Discussion of Experiments I and II --- p.55 / Chapter 4.5.2. --- Discussion of Experiments II and III --- p.57 / Chapter 4.5.3. --- Conclusion --- p.58 / Chapter 5. --- Cuff-based calibration approach for BP estimation in supine position --- p.61 / Chapter 5.1. --- Introduction --- p.61 / Chapter 5.2. --- Experiment protocol --- p.61 / Chapter 5.2.1. --- Experiment IV: exercise experiment in supine position in lab --- p.61 / Chapter 5.2.2. --- Experiment V: exercise experiment in supine position in PWH --- p.63 / Chapter 5.3. --- Data analysis --- p.65 / Chapter 5.3.1. --- Partition of signal trials and selection of datasets --- p.65 / Chapter 5.3.2. --- PPG waveform processing --- p.66 / Chapter 5.4. --- Experiment results --- p.68 / Chapter 5.4.1. --- Range and variation of reference SBP --- p.68 / Chapter 5.4.2. --- PAT-BP individual best regression --- p.69 / Chapter 5.4.3. --- Multiple regression using ZX and arm length --- p.72 / Chapter 5.4.4. --- One-cuff calibration improved by PPG waveform parameter --- p.72 / Chapter 5.5. --- Discussion --- p.74 / Chapter 6. --- Conclusion --- p.76
32

Evaluation of the wearable cuff-less blood pressure measuring devices.

January 2009 (has links)
Yan, Renfei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 69-77). / Abstract also in Chinese. / ABSTRACT --- p.I / ACKNOWLEDGEMENT --- p.V / LIST OF FIGURES --- p.VI / LIST OF TABLES --- p.VIII / LIST OF ABBREVIATIONS --- p.IX / Chapter CHAPTER 1. --- INTRODUCTION TO BLOOD PRESSURE MEASURING DEVICES AND EVALUATION STANDARDS --- p.1 / Chapter 1.1. --- Current situation on hypertension --- p.1 / Chapter A. --- Prevalence of hypertension --- p.1 / Chapter B. --- Low awareness of hypertension --- p.1 / Chapter 1.2. --- Calls for better management of hypertension --- p.2 / Chapter 1.3. --- Blood pressure measuring devices --- p.3 / Chapter A. --- Conventional devices and their limitations --- p.3 / Chapter B. --- Wearable cuff-less devices --- p.4 / Chapter 1.4. --- Evaluation of the wearable cuff-less devices --- p.6 / Chapter 1.5. --- Objectives of the thesis --- p.7 / Chapter 1.6. --- Structure of the thesis --- p.7 / Chapter CHAPTER 2. --- REVIEW ON CURRENT STANDARDS --- p.8 / Chapter 2.1. --- Introduction to current standards --- p.8 / Chapter A. --- AAMI standard --- p.8 / Chapter B. --- BHS protocol --- p.8 / Chapter C. --- ESH protocol --- p.9 / Chapter 2.2. --- Comparison of current standards --- p.9 / Chapter A. --- Evaluation scope --- p.9 / Chapter B. --- Validation protocol --- p.10 / Chapter C. --- Accuracy criteria --- p.10 / Chapter D. --- Testing reference --- p.13 / Chapter E. --- Recruitment of subjects --- p.13 / Chapter F. --- Ambulatory monitors --- p.14 / Chapter G. --- Special groups of population --- p.15 / Chapter H. --- Statistical considerations --- p.16 / Chapter 2.3. --- Major challenges for the evaluation of cuff-less devices --- p.17 / Chapter A. --- Lack of experimental data --- p.19 / Chapter B. --- Re-examination of the statistical considerations --- p.19 / Chapter C. --- Feature oriented design of the validation protocol --- p.19 / Chapter D. --- Selection of testing reference --- p.79 / Chapter CHAPTER 3. --- ERROR DISTRIBUTION MODEL --- p.21 / Chapter 3.1. --- Distribution assumption in current standards --- p.21 / Chapter 3.2. --- Distribution analysis from published reports --- p.22 / Chapter A. --- Methodology --- p.22 / Chapter B. --- Data analysis --- p.23 / Chapter C. --- Results --- p.23 / Chapter 3.3. --- Distribution analysis on a cuff-less device --- p.29 / Chapter A. --- Experiment --- p.29 / Chapter B. --- Data analysis --- p.31 / Chapter C. --- Results --- p.31 / Chapter 3.4. --- Discussion --- p.33 / Chapter A. --- Supporting evidence for t4 distribution --- p.33 / Chapter B. --- Implications for the application of t4 distribution --- p.34 / Chapter 3.5. --- Section Summary --- p.35 / Chapter CHAPTER 4. --- EVALUATION SCALE TO ASSESS THE ACCURACY --- p.36 / Chapter 4.1. --- Considerations for parameter selection --- p.37 / Chapter A. --- Outlying errors and system bias --- p.37 / Chapter B. --- Accuracy at different levels of blood pressure --- p.37 / Chapter 4.2. --- Description of selected parameters --- p.38 / Chapter 4.3. --- Theoretical relationship between “new´ح and “old´ح parameters --- p.38 / Chapter A. --- Mathematical relationship --- p.39 / Chapter B. --- Mapping relationship --- p.40 / Chapter 4.4. --- Assessment of accuracy at increasing blood pressure levels --- p.41 / Chapter A. --- Data transformation --- p.41 / Chapter B. --- Experimental study --- p.41 / Chapter 4.5. --- Discussion and application --- p.43 / Chapter A. --- Parameter selection --- p.43 / Chapter B. --- Sample size --- p.45 / Chapter C. --- Accuracy criteria --- p.46 / Chapter 4.6. --- Section summary --- p.47 / Chapter CHAPTER 5. --- FEATURE ORIENTED PROTOCOL DESIGN --- p.48 / Chapter 5.1. --- Rationale of accuracy assessment with BP change --- p.48 / Chapter 5.2. --- Experiment one --- p.49 / Chapter 5.3. --- Experiment two --- p.49 / Chapter 5.4. --- Data analysis --- p.49 / Chapter 5.5. --- Results --- p.50 / Chapter A. --- Experiment one --- p.50 / Chapter B. --- Experiment two --- p.52 / Chapter 5.6. --- Discussion --- p.58 / Chapter A. --- Difference between cuff-less and cuff-based devices --- p.58 / Chapter B. --- Correlation between accuracy and blood pressure changes --- p.58 / Chapter C. --- Inducement of blood pressure change --- p.59 / Chapter D. --- Other factors affect the accuracy --- p.60 / Chapter 5.7. --- Section summary --- p.61 / Chapter CHAPTER 6. --- PROPOSAL FOR THE EVALUATION OF WEARABLE CUFF-LESS DEVICES --- p.62 / Chapter 6.1. --- Scope --- p.62 / Chapter 6.2. --- Purpose --- p.62 / Chapter 6.3. --- Subject selection --- p.63 / Chapter 6.4. --- Main validation --- p.64 / Chapter A. --- Static test --- p.64 / Chapter B. --- Test with blood pressure change --- p.65 / Chapter C. --- Test after a certain period of time --- p.65 / Chapter 6.5. --- Data analysis and reporting --- p.66 / Chapter A. --- Statistical report --- p.66 / Chapter B. --- Graphical representation --- p.67 / Chapter 6.6. --- Conclusion and future work --- p.67 / REFERENCES --- p.69 / LIST OF PUBLICATIONS AND AWARDS --- p.78
33

The measurement of the pressure distribution over the wing of an aircraft in flight

McCarty, Matthew, Aerospace, Civil & Mechanical Engineering, Australian Defence Force Academy, UNSW January 2008 (has links)
A measurement system has been developed for use on a light aircraft to measure the pressure distribution over the wing surfaces. The measurement system was developed as a low-cost alternative to existing advanced measurement systems. The system consisted of low profile, low cost pressure sensors that interfaced digitally with microcontrollers for data acquisition. The pressure sensors and microcontrollers were developed into self-contained sensor modules with all electronic components mounted on flexible circuit board that formed the base of the modules. Two types of module were developed; a module with a single pressure sensor and a module with a row of seven pressure sensors at fifteen millimetre spacing. The total cost of the sensor modules was approximately ninety dollars for a single sensor module and one hundred and forty dollars for the seven sensor module. Studies were carried out using numerical methods to predict the pressure distribution over a NACA2412 airfoil. The numerical studies were used to evaluate the effect of adding the sensor modules to the wing, and the effect of the sensor distribution on measured force coefficients. Numerical predictions were made using the XFOIL software package. This software was validated using the Hess-Smith inviscid panel method. Flight testing was carried out with the pressure distribution measurement system to confirm the operation of the system and to make preliminary measurements. The flight testing focused on the measurement of steady state pressure distributions for comparison with the numerical predictions. Good agreement was found between the measured pressure distributions and the XFOIL predictions. Integration of the pressure distributions enabled comparison of normal force, lift force and quarter chord moment coefficients. The measured force coefficients showed the expected trends with angle of attack although it was found that the limited number of sensor modules used caused large error in the quarter chord moment coefficient compared to the numerical predictions.
34

Analysis and design of a contact pressure distribution measuring system

Qi, Haiming January 1987 (has links)
No description available.
35

Methodological and psychological predictors of the white coat effect

Newlove, Therese A. 05 1900 (has links)
The purpose of the study was to examine psychological and methodological factors which would predict the white coat effect (WCE). The WCE is defined as the difference (mm Hg) between ambulatory and office measured blood pressure (BP). Sixty three community volunteers participated in this study. Participants were divided into 3 Response style groups: (1) Office responders had ambulatory BP values which were lower than office BP, (2) Non responders showed a minimal difference between office and ambulatory BP, and (3) Home responders had significantly higher ambulatory BP compared to office BP. Participants were asked to have a series of BP readings taken by a physician, nurse and by themselves and participate in 24 hour ambulatory monitoring. State and trait self-report psychological measures were completed. Self measured BP was the most representative of ambulatory BP for the sample as a whole, and in particular for the Home responders. State anxiety, previously dismissed as mediating factor in the expression of the white coat effect, proved to discriminate between the groups. Office responders had significantly higher levels of state anxiety, directly related to BP measurements, compared to Home and Non responders. Habituation to the experience of having BP measured by a physician, and habituation of the anxiety prior to the BP measurement, was different among the three groups. Trait psychological variables did not distinguish group membership. Self measured systolic BP, state anxiety prior to self measured BP, habituation to physician measured BP and the anxiety preceding it, were entered as predictors variables in a discriminant function analyses. These variables were able to correctly classify group membership for 63% of the sample.
36

Pressure measurements for periodic fully developed turbulent flow in rectangular interrupted-plate ducts

McBrien, Robert K., 1958- January 1986 (has links)
No description available.
37

Recovery of refrigerant vapor leakage using high pressure psychrometrics

Wright, Jeffery Raymond 08 1900 (has links)
No description available.
38

Proximal gastric motor and sensory function in health and disease / by Geoffrey Stuart Hebbard.

Hebbard, Geoffrey Stuart January 1997 (has links)
Bibliography: leaves 205-258. / vii, 258 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The studies described in this thesis examine the mechanical function of the barostat. The barostat is then used to assess proximal gastric function in patients with gastro-oesophageal reflux disease, and the effects of hyperglycaemia on proximal gastric sensory and motor function in normal individuals. To detect the low pressures that may be important in determining gastric outflow, a high accuracy manometric recording system is developed ; patterns of intragastric pressure are then examined during gastric emptying of saline. Finally, a new barostat is designed and tested. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 1997
39

Specialised non-invasive blood pressure measurement algorithm

Lin, Han-Chun (Vivien) January 2007 (has links)
Blood pressure is one of the fundamental clinical measures. For more than 100 years, clinicians and researchers have used the mercury sphygmomanometer for blood pressure measurement. Environmental concern about mercury contamination has highlighted the need to find a replacement for traditional mercury sphygmomanometers. A number of currently used non-invasive blood pressure measurement methods have been studied in this research. The most commonly used automatic pressure monitoring method nowadays is the Oscillometric method. Height-based and Slope-based criteria are the two general means used to determine the systolic and diastolic pressures. However, these two criteria have many disputed points, making them debatable as a good standard for blood pressure measurement. For this reason, the auscultatory method continues to be the gold-standard for non-invasive blood pressure measurement. Current research uses a newly developed cuff with three different lengths of piezo film sensors and a pressure sensor to collect signals from the brachial artery. The objectives of the research are to process the measured signal from the sensors and develop a blood pressure measurement algorithm that will accurately determine the blood pressure noninvasively. Signal processing and heart beat / heart rate detection software have been developed. The best algorithm has been selected from three developed algorithms for further modification and validation. The final algorithm used two feed-forward Neural Networks to classify the acquired pressure signals into various regions of the pressure signals. The final algorithm has been tested on 258 measurements from 86 subjects. The testing result showed that the algorithm achieved grade A for both systolic and diastolic pressures according to the British Hypertension Society protocol. The mean differences (SD) between the observers and the developed algorithm were 1.44 (5.27) mmHg and 1.77 (6.17) mmHg for systolic and diastolic pressures, respectively, which also fulfilled the Association for the Advancement of Medical Instrumentation protocol. In conclusion, this algorithm was successfully developed and it is recommended for further clinical trial in a wider adult population. Further development of this algorithm also includes extending to other subgroups such as pregnant women, arrhythmia, diabetics and other subjects with diseases.
40

DESENVOLVIMENTO DE UM SISTEMA MULTICANAL PARA ANÁLISE DE PULSAÇÃO DE PRESSÃO EM COMPRESSORES ALTERNATIVOS VISANDO A MANUTENÇÃO PREDITIVA

RAMOS, JOSÉ DIVAL PASTOR 12 April 2006 (has links)
Submitted by Diogo Barreiros (diogo.barreiros@ufba.br) on 2017-02-17T16:41:33Z No. of bitstreams: 9 Capitulo I.pdf: 29639 bytes, checksum: 8007a2f7dfe2a8a68371ae454ff21265 (MD5) Capitulo II.pdf: 2398618 bytes, checksum: 67ec1b928bbd365a7a6ebc67b63a0cc3 (MD5) Capitulo III.pdf: 729546 bytes, checksum: 7778ce88975d7784a5c831e8af33cc12 (MD5) Capitulo IV.pdf: 39255 bytes, checksum: f005a001f7b707ab00d207d6718633b3 (MD5) Capitulo V.pdf: 424609 bytes, checksum: c070a2136bd33f21641c2d67d3b860d5 (MD5) Capitulo VI.pdf: 656297 bytes, checksum: 72bcce0a93526c29edd43b88091f3b94 (MD5) Capitulo VII.pdf: 1134199 bytes, checksum: 7fa6475029a4659167bab63ca25d6a37 (MD5) Capitulo VIII.pdf: 28984 bytes, checksum: 1c011016b6a3107609e9ebc952e018b4 (MD5) Elementos Pre-textuais.pdf: 78941 bytes, checksum: 38125074504363e58154371d872e9499 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-02-21T11:56:14Z (GMT) No. of bitstreams: 9 Capitulo I.pdf: 29639 bytes, checksum: 8007a2f7dfe2a8a68371ae454ff21265 (MD5) Capitulo II.pdf: 2398618 bytes, checksum: 67ec1b928bbd365a7a6ebc67b63a0cc3 (MD5) Capitulo III.pdf: 729546 bytes, checksum: 7778ce88975d7784a5c831e8af33cc12 (MD5) Capitulo IV.pdf: 39255 bytes, checksum: f005a001f7b707ab00d207d6718633b3 (MD5) Capitulo V.pdf: 424609 bytes, checksum: c070a2136bd33f21641c2d67d3b860d5 (MD5) Capitulo VI.pdf: 656297 bytes, checksum: 72bcce0a93526c29edd43b88091f3b94 (MD5) Capitulo VII.pdf: 1134199 bytes, checksum: 7fa6475029a4659167bab63ca25d6a37 (MD5) Capitulo VIII.pdf: 28984 bytes, checksum: 1c011016b6a3107609e9ebc952e018b4 (MD5) Elementos Pre-textuais.pdf: 78941 bytes, checksum: 38125074504363e58154371d872e9499 (MD5) / Made available in DSpace on 2017-02-21T11:56:14Z (GMT). No. of bitstreams: 9 Capitulo I.pdf: 29639 bytes, checksum: 8007a2f7dfe2a8a68371ae454ff21265 (MD5) Capitulo II.pdf: 2398618 bytes, checksum: 67ec1b928bbd365a7a6ebc67b63a0cc3 (MD5) Capitulo III.pdf: 729546 bytes, checksum: 7778ce88975d7784a5c831e8af33cc12 (MD5) Capitulo IV.pdf: 39255 bytes, checksum: f005a001f7b707ab00d207d6718633b3 (MD5) Capitulo V.pdf: 424609 bytes, checksum: c070a2136bd33f21641c2d67d3b860d5 (MD5) Capitulo VI.pdf: 656297 bytes, checksum: 72bcce0a93526c29edd43b88091f3b94 (MD5) Capitulo VII.pdf: 1134199 bytes, checksum: 7fa6475029a4659167bab63ca25d6a37 (MD5) Capitulo VIII.pdf: 28984 bytes, checksum: 1c011016b6a3107609e9ebc952e018b4 (MD5) Elementos Pre-textuais.pdf: 78941 bytes, checksum: 38125074504363e58154371d872e9499 (MD5) / A necessidade de novas metodologias para análise e monitoramento de compressores alternativos motivou o desenvolvimento de um sistema digital multicanal com capacidade de medir diferentes grandezas simultaneamente. Como base para este trabalho escolheu-se medir pressão dinâmica, vibração e deslocamento do pistão. O desenvolvimento deste trabalho dentro de um curso de Mecatrônica produziu um sistema simples e eficiente cujos resultados experimentais, apresentados sob a forma de gráficos e dados de desempenho, confirmaram os defeitos introduzidos artificialmente. Isto permitiu validar o Sistema de Diagnóstico de Compressores Alternativos (SDCA) e demonstrou o quanto este recurso é poderoso para o diagnóstico de defeitos, tanto nos componentes da parte de compressão (fluid end) quanto nos de acionamento (power end). Estas informações, transformadas em recomendações de reparo, serão a base para uma atuação preditiva dos setores de Planejamento de Manutenção.

Page generated in 0.081 seconds