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Sample records for cardiac output system

  1. A multiple-input multiple-output system for modeling the cardiac dynamics.

    Science.gov (United States)

    Monzon, Jorge E; Picaza, Carlos Alvarez; Pisarello, Maria I

    2011-01-01

    We describe the dynamics of the cardiovascular system by finding the input-output relationships in the state space of a functional cardiac model, based on state equations and observability criteria of control theory. The unit step response of the multiple-input multiple-output system model illustrates the damping effect of the arterial wall to the pulsatility of the heart. Our results show that hypertensive patients exhibit a lower inertia of the blood flow. PMID:22254491

  2. Clinical validation of a new thermodilution system for the assessment of cardiac output and volumetric parameters

    OpenAIRE

    Kiefer, Nicholas; Hofer, Christoph K; Marx, Gernot; Geisen, Martin; Giraud, Raphaël; Siegenthaler, Nils; Hoeft, Andreas; Bendjelid, Karim; Rex, Steffen

    2012-01-01

    ABSTRACT: INTRODUCTION: Transpulmonary thermodilution is used to measure cardiac output (CO), global end-diastolic volume (GEDV) and extravascular lung water (EVLW). A system has been introduced (VolumeView/EV1000™ system, Edwards Lifesciences, Irvine CA, USA) that employs a novel algorithm for the mathematical analysis of the thermodilution curve. Our aim was to evaluate the agreement of this method with the established PiCCO™ method (Pulsion Medical Systems SE, Munich, Germany, clinicaltria...

  3. Cardiac output during exercise

    DEFF Research Database (Denmark)

    Siebenmann, C; Rasmussen, P.; Sørensen, H.;

    2015-01-01

    Several techniques assessing cardiac output (Q) during exercise are available. The extent to which the measurements obtained from each respective technique compares to one another, however, is unclear. We quantified Q simultaneously using four methods: the Fick method with blood obtained from the...... right atrium (Q(Fick-M)), Innocor (inert gas rebreathing; Q(Inn)), Physioflow (impedance cardiography; Q(Phys)), and Nexfin (pulse contour analysis; Q(Pulse)) in 12 male subjects during incremental cycling exercise to exhaustion in normoxia and hypoxia (FiO2  = 12%). While all four methods reported a...... progressive increase in Q with exercise intensity, the slopes of the Q/oxygen uptake (VO2) relationship differed by up to 50% between methods in both normoxia [4.9 ± 0.3, 3.9 ± 0.2, 6.0 ± 0.4, 4.8 ± 0.2 L/min per L/min (mean ± SE) for Q(Fick-M), Q(Inn), QP hys and Q(Pulse), respectively; P = 0.001] and...

  4. Cardiac output monitoring

    Directory of Open Access Journals (Sweden)

    Mathews Lailu

    2008-01-01

    Full Text Available Minimally invasive and non-invasive methods of estimation of cardiac output (CO were developed to overcome the limitations of invasive nature of pulmonary artery catheterization (PAC and direct Fick method used for the measurement of stroke volume (SV. The important minimally invasive techniques available are: oesophageal Doppler monitoring (ODM, the derivative Fick method (using partial carbon dioxide (CO 2 breathing, transpulmonary thermodilution, lithium indicator dilution, pulse contour and pulse power analysis. Impedance cardiography is probably the only non-invasive technique in true sense. It provides information about haemodynamic status without the risk, cost and skill associated with the other invasive or minimally invasive techniques. It is important to understand what is really being measured and what assumptions and calculations have been incorporated with respect to a monitoring device. Understanding the basic principles of the above techniques as well as their advantages and limitations may be useful. In addition, the clinical validation of new techniques is necessary to convince that these new tools provide reliable measurements. In this review the physics behind the working of ODM, partial CO 2 breathing, transpulmonary thermodilution and lithium dilution techniques are dealt with. The physical and the physiological aspects underlying the pulse contour and pulse power analyses, various pulse contour techniques, their development, advantages and limitations are also covered. The principle of thoracic bioimpedance along with computation of CO from changes in thoracic impedance is explained. The purpose of the review is to help us minimize the dogmatic nature of practice favouring one technique or the other.

  5. The ability of the Vigileo-FloTrac system to measure cardiac output and track cardiac output changes during one-lung ventilation.

    Science.gov (United States)

    Suehiro, Koichi; Tanaka, Katsuaki; Yamada, Tokuhiro; Matsuura, Tadashi; Mori, Takashi; Funao, Tomoharu; Nishikawa, Kiyonobu

    2015-06-01

    This study was aimed at comparing the cardiac output (CO) measured by the Vigileo™-FloTrac™ system with that estimated by the thermodilution pulmonary artery catheter (PAC) during one-lung ventilation (OLV) and determining the reliability of this system in tracking phenylephrine-induced CO changes during OLV. Sixteen patients scheduled for descending aorta replacement were enrolled. The study was performed 30 min after starting OLV under stable hemodynamic conditions. We recorded hemodynamic variables, CO measured by PAC thermodilution (ICO), CO measured by Vigileo™-FloTrac™ system (Version 3.02, Edwards Lifesciences, Irvine, CA, USA) (APCO), and systemic vascular resistance index (SVRI) before (T0) and after (T1) phenylephrine (100 μg) administration. We used Bland-Altman analysis to compare ICO and APCO. Polar plot and four-quadrant plot were used to assess the tracking ability of the Vigileo™-FloTrac™ system against ICO after administration of phenylephrine. Ninety hemodynamic interventions were performed. Bland-Altman analysis revealed that the mean bias between APCO and ICO was 0.05 L/min and the percentage error, 46.9 %. Four-quadrant plot analysis showed a concordance rate of 24.7 %, while polar plot analysis showed that the concordance rate was 13.3 %; the angular bias, -45.9°; radial limit of agreement, 85.3°. The bias between APCO and ICO was significantly correlated with the SVRI value (p < 0.001, r(2) = 0.822). The reliability of the Vigileo™-FloTrac™ system during OLV to estimate CO and track phenylephrine-induced CO changes was not acceptable. PMID:25212705

  6. Effect of heat stress on cardiac output and systemic vascular conductance during simulated hemorrhage to presyncope in young men

    DEFF Research Database (Denmark)

    Ganio, Matthew S; Overgaard, Morten; Seifert, Thomas; Secher, Niels H; Johansson, Pär I; Meyer, Martin; Crandall, Craig G

    2012-01-01

    During moderate actual or simulated hemorrhage, as cardiac output decreases, reductions in systemic vascular conductance (SVC) maintain mean arterial pressure (MAP). Heat stress, however, compromises the control of MAP during simulated hemorrhage, and it remains unknown whether this response is due...

  7. Effectiveness of Human Atrial Natriuretic Peptide Supplementation in Pulmonary Edema Patients Using the Pulse Contour Cardiac Output System

    OpenAIRE

    Sakamoto, Yuichiro; Mashiko, Kunihiro; Saito, Nobuyuki; Matsumoto, Hisashi; Hara, Yoshiaki; Kutsukata, Noriyoshi; Yokota, Hiroyuki

    2010-01-01

    Purpose Atrial natriuretic peptide (ANP) has a variety of pharmacologic effects, including natriuresis, diuresis, vasodilatation, and suppression of the renin-angiotensin system. A recent study showed that ANP infusion improved hypoxemia and pulmonary hypertension in a lung injury model. On the other hand, the pulse contour cardiac output (PiCCO™) system (Pulsion Medical Systems, Munich, Germany) allows monitoring of the intravascular volume status and may be used to guide volume therapy in s...

  8. Methods in pharmacology: measurement of cardiac output

    OpenAIRE

    Geerts, Bart F; Aarts, Leon P; Jansen, Jos R.

    2011-01-01

    Many methods of cardiac output measurement have been developed, but the number of methods useful for human pharmacological studies is limited. The ‘holy grail’ for the measurement of cardiac output would be a method that is accurate, precise, operator independent, fast responding, non-invasive, continuous, easy to use, cheap and safe. This method does not exist today. In this review on cardiac output methods used in pharmacology, the Fick principle, indicator dilution techniques, arterial pul...

  9. Methods and apparatus for determining cardiac output

    Science.gov (United States)

    Cohen, Richard J. (Inventor); Mukkamala, Ramakrishna (Inventor); Sherman, Derin A. (Inventor)

    2010-01-01

    The present invention provides methods and apparatus for determining a dynamical property of the systemic or pulmonary arterial tree using long time scale information, i.e., information obtained from measurements over time scales greater than a single cardiac cycle. In one aspect, the invention provides a method and apparatus for monitoring cardiac output (CO) from a single blood pressure signal measurement obtained at any site in the systemic or pulmonary arterial tree or from any related measurement including, for example, fingertip photoplethysmography.According to the method the time constant of the arterial tree, defined to be the product of the total peripheral resistance (TPR) and the nearly constant arterial compliance, is determined by analyzing the long time scale variations (greater than a single cardiac cycle) in any of these blood pressure signals. Then, according to Ohm's law, a value proportional to CO may be determined from the ratio of the blood pressure signal to the estimated time constant. The proportional CO values derived from this method may be calibrated to absolute CO, if desired, with a single, absolute measure of CO (e.g., thermodilution). The present invention may be applied to invasive radial arterial blood pressure or pulmonary arterial blood pressure signals which are routinely measured in intensive care units and surgical suites or to noninvasively measured peripheral arterial blood pressure signals or related noninvasively measured signals in order to facilitate the clinical monitoring of CO as well as TPR.

  10. Impact of changes in systemic vascular resistance on a novel non-invasive continuous cardiac output measurement system based on pulse wave transit time: a report of two cases

    OpenAIRE

    Ishihara, Hironori; Tsutsui, Masato

    2013-01-01

    The inaccuracy of arterial waveform analysis for measuring continuos cardiac output (CCO) associated with changes in systemic vascular resistance (SVR) has been well documented. A new non-invasive continuous cardiac output monitoring system (esCCO) mainly utilizing pulse wave transit time (PWTT) in place of arterial waveform analysis has been developed. However, the trending ability of esCCO to measure cardiac output during changes in SVR remains unclear. After a previous multicenter study on...

  11. Issues in methods and measurement of thermodilution cardiac output.

    Science.gov (United States)

    Sommers, M S; Woods, S L; Courtade, M A

    1993-01-01

    Criterion-related validity of the thermodilution cardiac output technique for cardiac output measurement has to have a high correlation (r = .91 to .98) with the direct Fick method, the gold standard of cardiac output measurement. Issues that can affect validity of the measurements include the position of the pulmonary artery catheter, the rate of injection of the indicator solution, the volume and temperature of the injectate, the timing of the injection of indicator solution during the respiratory cycle, the position of the subject, and the presence of concomitant infusions. Variation in measurement can be limited by considering the delivery system for the indicator solution, by recording time-temperature cardiac output curves, and by considering normal biologic variations. PMID:8337161

  12. Cardiac output measured by the FloTrac/Vigileo system: Does the „plug and play“ principle work?

    Directory of Open Access Journals (Sweden)

    H. Maxeiner

    2010-06-01

    Full Text Available Background: Determination of cardiac output by the classic thermodilution technique is widely accepted to be the gold standard, but it is not without additional risks due to invasive catheterisation. Therefore, we compared it with the less invasive FloTracTM/VigileoTM-system based on an automated pulse contour analysis.Methods: 34 patients who underwent cardiac surgery with extracorporal circulation were included. In each patient, four measurements were performed. A software update split the patients into two groups: 19 of them were measured using software version V1.07, 15 were measured using software version V1.10.Results: Overall, 120 measurements were performed. Software version V1.07 showed a bias of -0.45l•(min•m2-1 and a precision of 0.53l•(min•m2-1. The percentage error was 45%. Software version V1.10 showed a bias of -0.26l•(min•m2-1 and a precision of 0.42l•(min•m2-1, the percentage error was 36% in this case. The differences were statistically significant with respect to the bias but not to the precision.Conclusion: Although software version V1.10 led to an improvement in the concordance with thermodilution technique, the percentage error exceeds the acceptable threshold of 28.28%. Therefore, in the setting of cardiac surgery the FloTracTM/VigileoTM-system cannot replace the thermodilution technique at present.

  13. Comparison of cardiac output measurement techniques

    DEFF Research Database (Denmark)

    Espersen, K; Jensen, E W; Rosenborg, D; Thomsen, J K; Eliasen, Kirstin; Olsen, Niels Vidiendal; Kanstrup, I L

    1995-01-01

    Simultaneously measured cardiac output obtained by thermodilution (TD), transcutaneous suprasternal ultrasonic Doppler (DOP), CO2-rebreathing (CR) and the direct Fick method (FI) were compared in eleven healthy subjects in a supine position (SU), a sitting position (SI), and during sitting exercise...

  14. [Cardiac output monitoring by impedance cardiography in cardiac surgery].

    Science.gov (United States)

    Shimizu, H; Seki, S; Mizuguchi, A; Tsuchida, H; Watanabe, H; Namiki, A

    1990-04-01

    The cardiac output monitoring by impedance cardiography, NCCOM3, was evaluated in adult patients (n = 12) who were subjected to coronary artery bypass grafting. Values of cardiac output measured by impedance cardiography were compared to those by the thermodilution method. Changes of base impedance level used as an index of thoracic fluid volume were also investigated before and after cardiopulmonary bypass (CPB). Correlation coefficient (r) of the values obtained by thermodilution with impedance cardiography was 0.79 and the mean difference was 1.29 +/- 16.9 (SD)% during induction of anesthesia. During the operation, r was 0.83 and the mean difference was -14.6 +/- 18.7%. The measurement by impedance cardiography could be carried out through the operation except when electro-cautery was used. Base impedance level before CPB was significantly lower as compared with that after CPB. There was a negative correlation between the base impedance level and central venous pressure (CVP). No patients showed any signs suggesting lung edema and all the values of CVP, pulmonary artery pressure and blood gas analysis were within normal ranges. From the result of this study, it was concluded that cardiac output monitoring by impedance cardiography was useful in cardiac surgery, but further detailed examinations will be necessary on the relationship between the numerical values of base impedance and the clinical state of the patients. PMID:2362347

  15. Assessment of cardiac output changes using a modified FloTrac/Vigileo™ algorithm in cardiac surgery patients

    OpenAIRE

    Senn, Alban; Button, Danny; Zollinger, Andreas; Hofer, Christoph K

    2009-01-01

    Introduction The FloTrac/Vigileo™ (Edwards Lifesciences, Irvine, CA, USA) allows pulse pressure-derived cardiac output measurement without external calibration. Software modifications were performed in order to eliminate initially observed deficits. The aim of this study was to assess changes in cardiac output determined by the FloTrac/Vigileo™ system (FCO) with an initially released (FCOA) and a modified (FCOB) software version, as well as changes in cardiac output from the PiCCOplus™ system...

  16. Estimation of cardiac output and systemic vascular resistance using a multivariate regression model with features selected from the finger photoplethysmogram and routine cardiovascular measurements

    OpenAIRE

    Lee, Qim Y; Stephen J. Redmond; Chan, Gregory SH; Middleton, Paul M; Steel, Elizabeth; Malouf, Philip; Critoph, Cristopher; Flynn, Gordon; O’Lone, Emma; Lovell, Nigel H

    2013-01-01

    Background Cardiac output (CO) and systemic vascular resistance (SVR) are two important parameters of the cardiovascular system. The ability to measure these parameters continuously and noninvasively may assist in diagnosing and monitoring patients with suspected cardiovascular diseases, or other critical illnesses. In this study, a method is proposed to estimate both the CO and SVR of a heterogeneous cohort of intensive care unit patients (N=48). Methods Spectral and morphological features w...

  17. Cardiac output and vasodilation in the vasovagal response

    DEFF Research Database (Denmark)

    Wieling, Wouter; Jardine, David L; de Lange, Frederik J;

    2016-01-01

    The simple faint is secondary to hypotension and bradycardia resulting in transient loss of consciousness. According to Ohm's law applied to the circulation, BP = SVR × CO, hypotension can result from a decrease in systemic vascular resistance (SVR), cardiac output (CO), or both. It is important...

  18. Kredsløbsmonitorering med lithium dilution cardiac output-systemet

    DEFF Research Database (Denmark)

    Christiansen, Christian; Hostrup, Anette; Tønnesen, Else;

    2008-01-01

    The lithium dilution cardiac output (LiDCO) system measures cardiac output beat-to-beat with high precision. The system is based on an arterial pulse power analysis which is calibrated every eight hours with a small non-pharmacological dose of lithium. The system is minimally invasive; it requires...

  19. Kredsløbsmonitorering af kritisk syge patienter med "pulse contour cardiac output"-systemet

    DEFF Research Database (Denmark)

    Afshari, Arash; Perner, Anders; Bonde, Jan

    2006-01-01

    The Pulse Contour Cardiac Output (PiCCO) monitoring system measures cardiac output with high precision and accuracy. The system may replace the pulmonary artery catheter in most critically ill patients because the rate of serious complications may be lower. Whether the use of dynamic or static fl...

  20. Comparing the accuracy of ES-BC, EIS-GS, and ES Oxi on body composition, autonomic nervous system activity, and cardiac output to standardized assessments

    Directory of Open Access Journals (Sweden)

    Lewis JE

    2011-09-01

    Full Text Available John E Lewis1, Stacey L Tannenbaum1, Jinrun Gao3, Angelica B Melillo1, Evan G Long1, Yaima Alonso2, Janet Konefal1, Judi M Woolger2, Susanna Leonard1, Prabjot K Singh1, Lawrence Chen1, Eduard Tiozzo1 1Department of Psychiatry and Behavioral Sciences, 2Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, 3State Farm Insurance, Bloomington, IL, USA Background and purpose: The Electro Sensor Complex (ESC is software that combines three devices using bioelectrical impedance, galvanic skin response, and spectrophotometry: (1 ES-BC (Electro Sensor-Body Composition; LD Technology, Miami, FL to assess body composition, (2 EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology to predict autonomic nervous system activity, and (3 ES Oxi (Electro Sensor Oxi; LD Technology to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA, EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA. Patients and methods: The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output. Results: We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001 with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001 with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R2 = 0.56, P = 0.03. For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001, after the first exercise stage (r = 0.79, P < 0.001, and after the second exercise stage (r = 0.86, P

  1. Peripheral vasodilatation determines cardiac output in exercising humans

    DEFF Research Database (Denmark)

    Bada, A A; Svendsen, J H; Secher, N H; Saltin, B; Mortensen, S P

    In dogs, manipulation of heart rate has no effect on the exercise-induced increase in cardiac output. Whether these findings apply to humans remain uncertain, because of the large differences in cardiovascular anatomy and regulation. To investigate the role of heart rate and peripheral...... arterial ATP infusion at rest. Exercise and ATP infusion increased cardiac output, leg blood flow and vascular conductance (P <0.05), whereas cerebral perfusion remained unchanged. During atrial pacing increasing heart rate by up to 54 beats min(−1), cardiac output did not change in any of the three...... demonstrate that the elevated cardiac output during steady-state exercise is regulated by the increase in skeletal muscle blood flow and venous return to the heart, whereas the increase in heart rate appears to be secondary to the regulation of cardiac output....

  2. Invasive and non-invasive methods for cardiac output measurement

    OpenAIRE

    Lavdaniti M.

    2008-01-01

    The hemodynamic status monitoring of high-risk surgical patients and critically ill patients inIntensive Care Units is one of the main objectives of their therapeutic management. Cardiac output is one of the mostimportant parameters for cardiac function monitoring, providing an estimate of whole body perfusion oxygen deliveryand allowing for an understanding of the causes of high blood pressure. The purpose of the present review is thedescription of cardiac output measurement methods as prese...

  3. Clinical evaluation of the flotrac/vigileo™ system for continuous cardiac output monitoring in patients undergoing regional anesthesia for elective cesarean section: a pilot study

    Science.gov (United States)

    Auler, José Otavio C.; Torres, Marcelo L. A.; Cardoso, Mônica M.; Tebaldi, Thais C.; Schmidt, André P.; Kondo, Mario M.; Zugaib, Marcelo

    2010-01-01

    BACKGROUND: Spinal anesthesia for cesarean delivery may cause severe maternal hypotension and a decrease in cardiac output. Compared to assessment of cardiac output via a pulmonary artery catheter, the FloTrac/Vigileo™ system may offer a less invasive technique. The aim of this study was to evaluate cardiac output and other hemodynamic measurements made using the FloTrac/Vigileo™ system in patients undergoing spinal anesthesia for elective cesarean section. METHODS: A prospective study enrolling 10 healthy pregnant women was performed. Hemodynamic parameters were continuously obtained at 15 main points: admission to surgery (two baseline measurements), after preload, after spinal anesthesia administration and 4 time points thereafter (4, 6, 8 and 10 min after anesthesia), at skin and uterine incision, newborn and placental delivery, oxytocin administration, end of surgery, and recovery from anesthesia. Hemodynamic therapy was guided by mean arterial pressure, and vasopressors were used as appropriate to maintain baseline values. A repeated measures ANOVA was used for data analysis. RESULTS: There was a significant increase in heart rate and a decrease of stroke volume and stroke volume index up to 10 min after spinal anesthesia (P < 0.01). Importantly, stroke volume variation increased immediately after newborn delivery (P < 0.001) and returned to basal values at the end of surgery. Further hemodynamic parameters showed no significant changes over time. DISCUSSION AND CONCLUSIONS: No significant hemodynamic effects, except for heart rate and stroke volume changes, were observed in pregnant women managed with preload and vasopressors when undergoing elective cesarean section and spinal anesthesia. PMID:20835557

  4. Clinical evaluation of the flotrac/vigileo™ system for continuous cardiac output monitoring in patients undergoing regional anesthesia for elective cesarean section: a pilot study

    Directory of Open Access Journals (Sweden)

    José Otavio Costa Auler Junior

    2010-06-01

    Full Text Available BACKGROUND: Spinal anesthesia for cesarean delivery may cause severe maternal hypotension and a decrease in cardiac output. Compared to assessment of cardiac output via a pulmonary artery catheter, the FloTrac/Vigileo™ system may offer a less invasive technique. The aim of this study was to evaluate cardiac output and other hemodynamic measurements made using the FloTrac/Vigileo™ system in patients undergoing spinal anesthesia for elective cesarean section. METHODS: A prospective study enrolling 10 healthy pregnant women was performed. Hemodynamic parameters were continuously obtained at 15 main points: admission to surgery (two baseline measurements, after preload, after spinal anesthesia administration and 4 time points thereafter (4, 6, 8 and 10 min after anesthesia, at skin and uterine incision, newborn and placental delivery, oxytocin administration, end of surgery, and recovery from anesthesia. Hemodynamic therapy was guided by mean arterial pressure, and vasopressors were used as appropriate to maintain baseline values. A repeated measures ANOVA was used for data analysis. RESULTS: There was a significant increase in heart rate and a decrease of stroke volume and stroke volume index up to 10 min after spinal anesthesia (P < 0.01. Importantly, stroke volume variation increased immediately after newborn delivery (P < 0.001 and returned to basal values at the end of surgery. Further hemodynamic parameters showed no significant changes over time. DISCUSSION AND CONCLUSIONS: No significant hemodynamic effects, except for heart rate and stroke volume changes, were observed in pregnant women managed with preload and vasopressors when undergoing elective cesarean section and spinal anesthesia.

  5. Lack of agreement between esophageal doppler cardiac output measurements and continuous pulse contour analysis during off-pump cardiac surgery

    Directory of Open Access Journals (Sweden)

    H. V. Groesdonk

    2010-03-01

    Full Text Available Objective: Transesophageal echo-Doppler cardiac output as well as arterial pulse contour analyses cardiac output are increasingly used for cardiac output monitoring. No data are available whether both techniques may be used interchangeably in patients undergoing cardiac surgery. Design: Prospective, observational study Setting: Operating rooms of a university affiliated hospital. Patients: 30 patients undergoing elective coronary artery bypass grafting surgery.Interventions: NoneMeasurements: 900 paired cardiac output measurements were obtained by pulse contour analysis following transpulmonary thermodilution equilibration by the PiCCO system (PiCCO, Pulsion, Munich, Germany and by the HemoSonic esophageal doppler monitor (HemoSonic 100; Arrow International, Reading, PA. Measurements were performed within the first hour after induction of anesthesia. Results: Bland-Altman analysis of the complete data set showed a mean difference (bias of - 0.12 l/min (95% CI -0.06 to -0.18 with limits of agreement + 1.8 l/min to -1.6 l/min (upper 95% CI 1.78 to 1.98; lower 95% CI -1.74 to -1.54, the percentage error was + 37% to -44.5%. Transesophageal echo-Doppler cardiac output closely correlated (r = 0.75, p < 0.0001 with pulse-contour analyses cardiac output. Conclusions: Several studies have shown the accuracy of calibrated pulse contour cardiac output measurements in patients undergoing cardiac surgery. Thus, the present data question the reliability of transesophageal echo-Doppler derived cardiac output measurements in this setting and may have implications for using transesophageal echo-Doppler during goal-directed hemodynamic optimization.

  6. Lack of agreement and trending ability of the endotracheal cardiac output monitor compared with thermodilution

    DEFF Research Database (Denmark)

    Møller-Sørensen, H; Hansen, K L; Ostergaard, M; Andersen, L W; Møller, Kirsten

    2012-01-01

    BACKGROUND: Minimally invasive monitoring systems of central haemodynamics are gaining increasing popularity. The present study investigated the precision of the endotracheal cardiac output monitor (ECOM) system and its agreement with pulmonary artery catheter thermodilution (PAC TD) for measuring...

  7. Mini invasive hemodynamic monitoring: from arterial pressure to cardiac output

    OpenAIRE

    GIORGIO DELLA ROCCA; MAURIZIO CECCONI; MARIA GABRIELLA COSTA

    2008-01-01

    To evaluate the Cardiac Output (CO) the standard invasive pulmonary artery catheter (PAC) is considered today the gold standard. The major criticism to the PAC is that its level of invasiveness is not supported by an improvement in patient's outcome. The interest to lesser and lesser invasive techniques is high. Therefore, the alternative techniques have been recently developed.Cardiac Output can be monitored continuously by different devices that analyze the arterial waveform to track change...

  8. A Numerical Investigation of Heat Transfer Cardiac Output Measurements

    OpenAIRE

    Fotheringham, P.; A R Gourlay; McKee, S.; Andrews, S

    2005-01-01

    Measurement of cardiac output is often investigated using a technique based on hot-film anemometry. Here, we discuss a modification to hot-film anemometry, which involves a cylindrical heating element mounted flush on the surface of a typical Swan-Ganz catheter. In contrast to traditional thermodilution, the method discussed here has the potential to allow continuous monitoring of cardiac output.This paper demonstrates that there is a simple approximate relationship between the power input to...

  9. Modelflow underestimates cardiac output in heat-stressed individuals

    DEFF Research Database (Denmark)

    Shibasaki, Manabu; Wilson, Thad E; Bundgaard-Nielsen, Morten; Seifert, Thomas; Secher, Niels H; Crandall, Craig G

    2011-01-01

    Modelflow accurately tracks thermodilution-derived cardiac outputs during whole body heat stress. Acute changes of cardiac output were accomplished via lower-body negative pressure (LBNP) during normothermic and heat-stressed conditions. In nine healthy normotensive subjects, arterial pressure was measured...... similar with cardiac outputs measured by thermodilution (6.4 ± 0.8 l/min). The subsequent reduction in cardiac output during LBNP was also similar among these methods. Whole body heat stress elevated internal temperature from 36.6 ± 0.3 to 37.8 ± 0.4°C and increased cardiac output from 6.4 ± 0.8 to 10.......9 ± 2.0 l/min when evaluated with thermodilution (P <0.001). However, the increase in cardiac output estimated from the Modelflow method for both arterial cannulation (2.3 ± 1.1 l/min) and Finometer (1.5 ± 1.2 l/min) was attenuated compared with thermodilution (4.5 ± 1.4 l/min, both P <0.01). Finally...

  10. Cardiac conduction system

    Science.gov (United States)

    The cardiac conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals ... to contract. The main components of the cardiac conduction system are the SA node, AV node, bundle ...

  11. Determination of myocardial energetic output for cardiac rhythm pacing.

    Science.gov (United States)

    Herman, Dalibor; Prevorovská, Svetlana; Marsík, Frantisek

    2007-12-01

    This research is aimed to the determination of the changes in the cardiac energetic output for three different modes of cardiac rhythm pacing. The clinical investigation of thirteen patients with the permanent dual-chamber pacemaker implantation was carried out. The patients were taken to echocardiography examination conducted by way of three pacing modes (AAI, VVI and DDD). The myocardial energetic parameters-the stroke work index (SWI) and the myocardial oxygen consumption (MVO2) are not directly measurable, however, their values can be determined using the numerical model of the human cardiovascular system. The 24-segment hemodynamical model (pulsating type) of the human cardiovascular system was used for the numerical simulation of the changes of myocardial workload for cardiac rhythm pacing. The model was fitted by well-measurable parameters for each patient. The calculated parameters were compared using the two-tailed Student's test. The differences of SWI and MVO2 between the modes AAI and VVI and the modes DDD and VVI are statistically significant (P0.05). PMID:18080208

  12. Noninvasive continuous cardiac output monitoring in perioperative and intensive care medicine.

    Science.gov (United States)

    Saugel, B; Cecconi, M; Wagner, J Y; Reuter, D A

    2015-04-01

    The determination of blood flow, i.e. cardiac output, is an integral part of haemodynamic monitoring. This is a review on noninvasive continuous cardiac output monitoring in perioperative and intensive care medicine. We present the underlying principles and validation data of the following technologies: thoracic electrical bioimpedance, thoracic bioreactance, vascular unloading technique, pulse wave transit time, and radial artery applanation tonometry. According to clinical studies, these technologies are capable of providing cardiac output readings noninvasively and continuously. They, therefore, might prove to be innovative tools for the assessment of advanced haemodynamic variables at the bedside. However, for most technologies there are conflicting data regarding the measurement performance in comparison with reference methods for cardiac output assessment. In addition, each of the reviewed technology has its own limitations regarding applicability in the clinical setting. In validation studies comparing cardiac output measurements using these noninvasive technologies in comparison with a criterion standard method, it is crucial to correctly apply statistical methods for the assessment of a technology's accuracy, precision, and trending capability. Uniform definitions for 'clinically acceptable agreement' between innovative noninvasive cardiac output monitoring systems and criterion standard methods are currently missing. Further research must aim to further develop the different technologies for noninvasive continuous cardiac output determination with regard to signal recording, signal processing, and clinical applicability. PMID:25596280

  13. Automated non-invasive measurement of cardiac output: comparison of electrical bioimpedance and carbon dioxide rebreathing techniques.

    OpenAIRE

    Smith, S A; Russell, A.E.; West, M. J.; Chalmers, J

    1988-01-01

    Two commercial automated, non-invasive systems for estimation of cardiac output were evaluated. Values of cardiac output obtained by electrical bioimpedance cardiography (BoMed NCCOM3 machine) were compared with values derived from an indirect Fick technique that uses carbon dioxide rebreathing (Gould 9000 IV system) during 103 simultaneous measurements made at rest in 19 randomly selected subjects and on exercise in 11 subjects. Cardiac output values obtained with impedance cardiography were...

  14. Evaluation of heavy water for indicator dilution cardiac output measurement

    Energy Technology Data Exchange (ETDEWEB)

    Schreiner, M.S.; Leksell, L.G.; Neufeld, G.R. (Univ. of Pennsylvania School of Medicine, Philadelphia (USA))

    1989-10-01

    We evaluated deuterium oxide (D2O) as a tracer for cardiac output measurements. Cardiac output measurements made by thermodilution were compared with those made by indicator dilution with D2O and indocyanine green as tracers. Five triplicate measurements for each method were made at intervals of 30 minutes in each of 9 anesthetized, mechanically ventilated goats. Cardiac output ranged between 0.68 and 3.79 L/min. The 45 data points yielded a correlation coefficient of 0.948 for the comparison of D2O indicator dilution cardiac output measurements with thermodilution measurements and a linear regression slope of 1.046. D2O indicator dilution measurements were biased by -0.11 +/- 0.22 L/min compared with thermodilution measurements and had a standard deviation of +/- 0.12 L/min for triplicate measurements. Hematocrits ranging between 20 and 50 vol% had no effect on optical density for D2O. D2O is more stable than indocyanine green and approximately one-tenth the price (40 cents per injection compared with $4). The basic instrumentation cost of approximately $9,000 is an additional initial expense, but provides the ability to perform pulmonary extravascular water measurements with a double-indicator dilution technique. D2O has potential as a tracer for the clinical determination of indicator dilution cardiac output measurements and pulmonary extravascular water measurements.

  15. Determination of myocardial energetic output for cardiac rhythm pacing

    OpenAIRE

    Heřman, Dalibor; Převorovská, Světlana; Maršík, František

    2007-01-01

    This research is aimed to the determination of the changes in the cardiac energetic output for three different modes of cardiac rhythm pacing. The clinical investigation of thirteen patients with the permanent dual-chamber pacemaker implantation was carried out. The patients were taken to echocardiography examination conducted by way of three pacing modes (AAI, VVI and DDD). The myocardial energetic parameters—the stroke work index (SWI) and the myocardial oxygen consumption (MVO2) are not di...

  16. Relationship between cardiac output and effective renal plasma flow in patients with cardiac disease

    Energy Technology Data Exchange (ETDEWEB)

    McGriffin, D.; Tauxe, W.N.; Lewis, C.; Karp, R.; Mantle, J.

    1984-12-01

    The relationship between effective renal plasma flow (ERPF) and cardiac output was examined in 46 patients (22 with congestive heart failure and 24 following cardiac surgical procedures) by simultaneously measuring the global ERPF by the single-injection method and cardiac output by the thermodilution method. Of the patients in the heart-failure group, 21 also had pulmonary artery end diastolic pressure (PAEDP) recorded at the same time. ERPF and cardiac output were found to be related by the regression equations: cardiac output = 2.08 + 0.0065 ERPF (r, 080), with a SE of estimate of 0.81 l/min. ERPF and PAEDP were related by the regression equation: PAEDP = 42.02 - 0.0675 ERPF (r, 0.86), with a SE of estimate of 5.5 mm Hg. ERPF may be a useful noninvasive method of estimating cardiac output if it is known that no intrinsic kidney disease is present, and if the error of 0.81 l/min (1 SE of estimate) is within the range of clinical usefulness. The error is principally attributable to the determination of cardiac output by the thermodilution method.

  17. Minimally invasive or noninvasive cardiac output measurement: an update.

    Science.gov (United States)

    Sangkum, Lisa; Liu, Geoffrey L; Yu, Ling; Yan, Hong; Kaye, Alan D; Liu, Henry

    2016-06-01

    Although cardiac output (CO) by pulmonary artery catheterization (PAC) has been an important guideline in clinical management for more than four decades, some studies have questioned the clinical efficacy of CO in certain patient populations. Further, the use of CO by PAC has been linked to numerous complications including dysrhythmia, infection, rupture of pulmonary artery, injury to adjacent arteries, embolization, pulmonary infarction, cardiac valvular damage, pericardial effusion, and intracardiac catheter knotting. The use of PAC has been steadily declining over the past two decades. Minimally invasive and noninvasive CO monitoring have been studied in the past two decades with some evidence of efficacy. Several different devices based on pulse contour analysis are available currently, including the uncalibrated FloTrac/Vigileo system and the calibrated PiCCO and LiDCO systems. The pressure-recording analytical method (PRAM) system requires only an arterial line and is commercially available as the MostCare system. Transesophageal echocardiography (TEE) can measure CO by non-Doppler- or Doppler-based methods. The partial CO2 rebreathing technique, another method to measure CO, is marketed by Novametrix Medical Systems as the NICO system. Thoracic electrical bioimpedance (TEB) and electric bioreactance (EB) are totally noninvasive CO monitoring. Nexfin HD and the newer ClearSight systems are examples of noninvasive CO monitoring devices currently being marketed by Edwards Lifesciences. The developing focus in CO monitoring devices appears to be shifting to tissue perfusion and microcirculatory flow and aimed more at markers that indicate the effectiveness of circulatory and microcirculatory resuscitations. PMID:26961819

  18. Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients

    Directory of Open Access Journals (Sweden)

    Hann Christopher E

    2010-11-01

    Full Text Available Abstract The application of positive end expiratory pressure (PEEP in mechanically ventilated (MV patients with acute respiratory distress syndrome (ARDS decreases cardiac output (CO. Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness. This paper examines combining models of diffusion resistance and lung mechanics, to help predict CO changes due to PEEP. The CO estimator uses an initial measurement of pulmonary shunt, and estimations of shunt changes due to PEEP to predict CO at different levels of PEEP. Inputs to the cardiac model are the PV loops from the ventilator, as well as the oxygen saturation values using known respiratory inspired oxygen content. The outputs are estimates of pulmonary shunt and CO changes due to changes in applied PEEP. Data from two published studies are used to assess and initially validate this model. The model shows the effect on oxygenation due to decreased CO and decreased shunt, resulting from increased PEEP. It concludes that there is a trade off on oxygenation parameters. More clinically importantly, the model also examines how the rate of CO drop with increased PEEP can be used as a method to determine optimal PEEP, which may be used to optimise MV therapy with respect to the gas exchange achieved, as well as accounting for the impact on the cardiovascular system and its management.

  19. Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients.

    Science.gov (United States)

    Sundaresan, Ashwath; Chase, J Geoffrey; Hann, Christopher E; Shaw, Geoffrey M

    2010-01-01

    The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness.This paper examines combining models of diffusion resistance and lung mechanics, to help predict CO changes due to PEEP. The CO estimator uses an initial measurement of pulmonary shunt, and estimations of shunt changes due to PEEP to predict CO at different levels of PEEP. Inputs to the cardiac model are the PV loops from the ventilator, as well as the oxygen saturation values using known respiratory inspired oxygen content. The outputs are estimates of pulmonary shunt and CO changes due to changes in applied PEEP. Data from two published studies are used to assess and initially validate this model.The model shows the effect on oxygenation due to decreased CO and decreased shunt, resulting from increased PEEP. It concludes that there is a trade off on oxygenation parameters. More clinically importantly, the model also examines how the rate of CO drop with increased PEEP can be used as a method to determine optimal PEEP, which may be used to optimise MV therapy with respect to the gas exchange achieved, as well as accounting for the impact on the cardiovascular system and its management. PMID:21108836

  20. Pulse contour-derived cardiac output in hemodialysis patients

    DEFF Research Database (Denmark)

    Cordtz, Joakim; Ladefoged, Soeren D

    2010-01-01

    analysis, namely the Finometer monitor (FNM) for further use on patients dialyzing on a central vascular catheter. Fifty simultaneous cardiac output measurements were obtained during hemodialysis sessions in 25 patients. The internal variability of the FNM measurements was assessed by comparing 24 pairs of...

  1. Pulse contour-derived cardiac output in hemodialysis patients

    DEFF Research Database (Denmark)

    Cordtz, Joakim; Ladefoged, Soeren D

    2010-01-01

    Reliable methods for cardiac output determination are essential for studying the pathophysiology of intradialytic hypotension. Use of the current gold standard, the Transonic monitor, requires an arteriovenous fistula. We wished to verify the accuracy of a method based on finger pulse contour...

  2. Invasive and non-invasive methods for cardiac output measurement

    Directory of Open Access Journals (Sweden)

    Lavdaniti M.

    2008-01-01

    Full Text Available The hemodynamic status monitoring of high-risk surgical patients and critically ill patients inIntensive Care Units is one of the main objectives of their therapeutic management. Cardiac output is one of the mostimportant parameters for cardiac function monitoring, providing an estimate of whole body perfusion oxygen deliveryand allowing for an understanding of the causes of high blood pressure. The purpose of the present review is thedescription of cardiac output measurement methods as presented in the international literature. The articles documentthat there are many methods of monitoring the hemodynamic status of patients, both invasive and non-invasive, themost popular of which is thermodilution. The invasive methods are the Fick method and thermodilution, whereasthe non-invasive methods are oeshophaegeal Doppler, transoesophageal echocardiography, lithium dilution, pulsecontour, partial CO2 rebreathing and thoracic electrical bioimpedance. All of them have their advantages and disadvantages,but thermodilution is the golden standard for critical patients, although it does entail many risks. The idealsystem for cardiac output monitoring would be non-invasive, easy to use, reliable and compatible in patients. A numberof research studies have been carried out in clinical care settings, by nurses as well as other health professionals, for thepurpose of finding a method of measurement that would have the least disadvantages. Nevertheless, the thermodilutiontechnique remains the most common approach in use today.

  3. Cardiac Output Measurement in Patients with an Implanted Pacemaker

    Czech Academy of Sciences Publication Activity Database

    Vondra, Vlastimil; Halámek, Josef; Viščor, Ivo; Jurák, Pavel; Novák, M.

    Danvers : Institute of Electrical and Electronics Engineers, Inc., 2007, s. 916-918. ISBN 978-1-4244-0787-3. ISSN 1557-170X. [Annual International Conference of the IEEE Engineering in Medicine and Biology Society /29./. Lyon (FR), 23.08.2007-26.08.2007] R&D Projects: GA ČR GA102/06/0136 Institutional research plan: CEZ:AV0Z20650511 Keywords : cardiac output measurement * implanted pacemaker Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  4. Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients

    OpenAIRE

    Hann Christopher E; Chase J; Sundaresan Ashwath; Shaw Geoffrey M

    2010-01-01

    Abstract The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness. This paper examines...

  5. High-output cardiac failure secondary to multiple vascular malformations in the liver: case report

    Energy Technology Data Exchange (ETDEWEB)

    Spaner, S.; Demeter, S. [Univ. of Alberta, Dept. of Radiology and Diagnostic Imaging, Edmonton, Alberta (Canada); Lien, D. [Univ. of Alberta, Dept. of Pulmonary Medicine, Edmonton, Alberta (Canada); Shapiro, J. [Univ. of Alberta, Dept. of Surgery, Edmonton, Alberta (Canada); McCarthy, M.; Raymond, G. [Univ. of Alberta, Dept. of Radiology and Diagnostic Imaging, Edmonton, Alberta (Canada)

    2001-08-01

    High-output cardiac failure is associated with several systemic illnesses, including hyperthyroidism, thiamine deficiency, severe anemia, multiple myeloma, Paget's disease of bone and Osler-Weber-Rendu syndrome. We present an unusual case of a woman with high-output cardiac failure as a result of multiple arteriovenous fistulas in the liver, most likely representing an unusual variant of Osler-Weber-Rendu syndrome (i.e., no other telangiectasias or a family history of vascular malformations was demonstrated). (author)

  6. Validation of a new spectrometer for noninvasive measurement of cardiac output

    International Nuclear Information System (INIS)

    Acetylene is a blood-soluble gas and for many years its uptake rate during rebreathing tests has been used to calculate the flow rate of blood through the lungs (normally equal to cardiac output) as well as the volume of lung tissue. A new, portable, noninvasive instrument for cardiac output determination using the acetylene uptake method is described. The analyzer relies on nondispersive IR absorption spectroscopy as its principle of operation and is configured for extractive (side-stream) sampling. The instrument affords exceptionally fast (30 ms, 10%-90%, 90%-10%, at 500 mL min-1 flow rates), interference-free, simultaneous measurement of acetylene, sulfur hexafluoride (an insoluble reference gas used in the cardiac output calculation), and carbon dioxide (to determine alveolar ventilation), with good (typically ±2% full-scale) signal-to-noise ratios. Comparison tests with a mass spectrometer using serially diluted calibration gas samples gave excellent (R2>0.99) correlation for all three gases, validating the IR system's linearity and accuracy. A similar level of agreement between the devices also was observed during human subject C2H2 uptake tests (at rest and under incremental levels of exercise), with the instruments sampling a common extracted gas stream. Cardiac output measurements by both instruments were statistically equivalent from rest to 90% of maximal oxygen consumption; the physiological validity of the measurements was confirmed by the expected linear relationship between cardiac output and oxygen consumption, with both the slope and intercept in the published range. These results indicate that the portable, low-cost, rugged prototype analyzer discussed here is suitable for measuring cardiac output noninvasively in a point-of-care setting

  7. Nonlinear input-output systems

    Science.gov (United States)

    Hunt, L. R.; Luksic, Mladen; Su, Renjeng

    1987-01-01

    Necessary and sufficient conditions that the nonlinear system dot-x = f(x) + ug(x) and y = h(x) be locally feedback equivalent to the controllable linear system dot-xi = A xi + bv and y = C xi having linear output are found. Only the single input and single output case is considered, however, the results generalize to multi-input and multi-output systems.

  8. Aspects of the continuous clinical measurement of arterial blood pressure and cardiac output

    International Nuclear Information System (INIS)

    In this paper the authors try to classify circulatory measurements as to certain characteristics such as ''activeness'', ''invasivenesss'', etc. Next they turn to defining some fundamental measurements in the blood circulation and focus attention on the continuous measurement of systemic arterial pressure and flow to finally emphasize the inaccuracy of clinical cardiac output methods. The conclusion is that clinical circulatory measurement methods have accuracies at least an order of magnitude worse than common physical methods used in electrical or mechanical engineering. (Auth.)

  9. Non-invasive cardiac output monitoring in neonates using bioreactance: a comparison with echocardiography.

    LENUS (Irish Health Repository)

    Weisz, Dany E

    2012-01-01

    Non-invasive cardiac output monitoring is a potentially useful clinical tool in the neonatal setting. Our aim was to evaluate a new method of non-invasive continuous cardiac output (CO) measurement (NICOM™) based on the principle of bioreactance in neonates.

  10. Simultaneous cardiac output and regional myocardial perfusion determination with PET and nitrogen 13 ammonia

    DEFF Research Database (Denmark)

    Hove, Jens D; Kofoed, Klaus F; Wu, Hsiao M;

    2003-01-01

    The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia.......The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia....

  11. Non-invasive determination of cardiac output by Doppler echocardiography and electrical bioimpedance

    OpenAIRE

    Silke, Bernard

    1990-01-01

    Cardiac output measured by thermodilution in 25 patients within 24 hours of acute myocardial infarction was compared with cardiac output measured by Doppler echocardiography (24 patients) and electrical bioimpedance (25 patients). The mean (range) cardiac outputs measured by Doppler (4.03 (2.2-6.0) 1/min) and electrical bioimpedance (3.79 (1.1-6.2) 1/min) were similar to the mean thermodilution value (3.95 (2.1-6.2) 1/min). Both non-invasive techniques agreed closely with thermodilution in mo...

  12. Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration

    OpenAIRE

    Amann Matthias; Trabold Benedikt; Schweiger Stefan; Keyl Cornelius; Bele Sylvia; Prasser Christopher; Welnhofer Julia; Wiesenack Christoph

    2007-01-01

    Abstract Background Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (COPAC) measurement by the pulmonary artery catheter (PAC). However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (COAP) device (FloTrac™, Vigileo™; Edwards Lifesciences, Irvine, CA, USA) only requires access to the radial or femoral artery using a s...

  13. The decrease of cardiac chamber volumes and output during positive-pressure ventilation

    DEFF Research Database (Denmark)

    Kristensen, Kasper Kyhl; Ahtarovski, Kiril Aleksov; Iversen, Kasper;

    2013-01-01

    effect of PPV on the central circulation by studying cardiac chamber volumes with cardiac magnetic resonance imaging (CMR). We hypothesized that PPV lowers cardiac output (CO) mainly via the Frank-Starling relationship. In 18 healthy volunteers, cardiac chamber volumes and flow in aorta and the pulmonary......Positive-pressure ventilation (PPV) is widely used for treatment of acute cardiorespiratory failure, occasionally at the expense of compromised cardiac function and arterial blood pressure. The explanation why has largely rested on interpretation of intracardiac pressure changes. We evaluated the...... artery were measured by CMR during PPV levels of 0, 10, and 20 cmH2O applied via a respirator and a face mask. All cardiac chamber volumes decreased in proportion to the level of PPV. Following 20-cmH2O PPV, the total diastolic and systolic cardiac volumes (±SE) decreased from 605 (±29) ml to 446 (±29...

  14. Determination of myocardial energetic output for cardiac rhythm pacing

    Czech Academy of Sciences Publication Activity Database

    Heřman, D.; Převorovská, Světlana; Maršík, František

    2007-01-01

    Roč. 7, č. 4 (2007), s. 156-161. ISSN 1567-8822 R&D Projects: GA ČR GA106/03/1073 Institutional research plan: CEZ:AV0Z20760514 Keywords : heart arrhythmia * cardiac pacing modes * numerical simulation Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  15. Cardiac output and vasodilation in the vasovagal response: An analysis of the classic papers.

    Science.gov (United States)

    Wieling, Wouter; Jardine, David L; de Lange, Frederik J; Brignole, Michele; Nielsen, Henning B; Stewart, Julian; Sutton, Richard

    2016-03-01

    The simple faint is secondary to hypotension and bradycardia resulting in transient loss of consciousness. According to Ohm's law applied to the circulation, BP = SVR × CO, hypotension can result from a decrease in systemic vascular resistance (SVR), cardiac output (CO), or both. It is important to understand that when blood pressure (BP) is falling, SVR and CO do not change reciprocally as they do in the steady state. In 1932, Lewis, assuming that decreased SVR alone accounted for hypotension, defined "the vasovagal response" along pathophysiologic lines to denote the association of vasodilation with vagal-induced bradycardia in simple faint. Studies performed by Barcroft and Sharpey-Schafer between 1940 and 1950 used volume-based plethysmography to demonstrate major forearm vasodilation during extreme hypotension and concluded that the main mechanism for hypotension was vasodilation. Plethysmographic measurements were intermittent and not frequent enough to capture rapid changes in blood flow during progressive hypotension. However, later investigations by Weissler, Murray, and Stevens performed between 1950 and 1970 used invasive beat-to-beat BP measurements and more frequent measurements of CO using the Fick principle. They demonstrated that CO significantly fell before syncope, and little vasodilation occurred until very late in the vasovagal reaction Thus, since the 1970s, decreasing cardiac output rather than vasodilation has been regarded as the principal mechanism for the hypotension of vasovagal syncope. PMID:26598322

  16. Validation of noninvasive pulse contour cardiac output using finger arterial pressure in cardiac surgery patients requiring fluid therapy

    NARCIS (Netherlands)

    Hofhuizen, C.M.; Lansdorp, B.; Hoeven, J.G. van der; Scheffer, G.J.; Lemson, J.

    2014-01-01

    INTRODUCTION: Nexfin (Edwards Lifesciences, Irvine, CA) allows for noninvasive continuous monitoring of blood pressure (ABPNI) and cardiac output (CONI) by measuring finger arterial pressure (FAP). To evaluate the accuracy of FAP in measuring ABPNI and CONI as well as the adequacy of detecting chang

  17. Validation of noninvasive pulse contour cardiac output using finger arterial pressure in cardiac surgery patients requiring fluid therapy

    NARCIS (Netherlands)

    Hofhuizen, Charlotte; Lansdorp, Benno; Hoeven, van der Johannes G.; Scheffer, Gert-Jan; Lemson, Joris

    2014-01-01

    Introduction Nexfin (Edwards Lifesciences, Irvine, CA) allows for noninvasive continuous monitoring of blood pressure (ABPNI) and cardiac output (CONI) by measuring finger arterial pressure (FAP). To evaluate the accuracy of FAP in measuring ABPNI and CONI as well as the adequacy of detecting change

  18. Temporary epicardial left ventricular and biventricular pacing improves cardiac output after cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    García-Bengochea Jose B

    2012-10-01

    Full Text Available Abstract Background To evaluate, with different pacing modes, acute changes in left ventricular systolic function, obtained by continuous cardiac output thermodilution in various subsets of patients undergoing cardiopulmonary bypass surgery. Increments of mean arterial pressure and cardiac output were considered the end point. Methods Fifty cases electively submitted to cardiac surgery were analyzed. Isolated valve surgery 62%, coronary revascularization 30% and 8% mixed disease. Left ventricular ejection fraction was preserved in 50%,36% had moderate depression,(EF 36%-50% whereas 14% had severe depression (EF  Results Right atrium-right ventricular pacing, decreased significantly mean arterial pressure and cardiac output (2.3% in the overall population and in the subgroups studied. Right atrium-left ventricle, increased mean arterial pressure and cardiac output in 79% of patients and yielded cardiac output increments of 7.5% (0.40 l/m in the low ejection fraction subgroup and 7.3% (0.43 l/m in the left bundle branch block subset. In atrial fibrillation patients, left ventricular and biventricular pacing produced a significant increase in cardiac output 8.5% (0.39 l/min and 11.6% (0.53 l/min respectively. The dP/dt max increased significantly with both modes (p = 0.021,p = 0.028. Conclusion Right atrial-right ventricular pacing generated adverse hemodynamic effects. Right atrium-left ventricular pacing produced significant CO improvement particularly in cases with depressed ventricular function and left bundle branch block. The greatest increments were observed with left ventricular or biventricular pacing in atrial fibrillation with depressed ejection fraction.

  19. Management of the Low Cardiac Output Syndrome Following Surgery for Congenital Heart Disease.

    Science.gov (United States)

    Chandler, Heather K; Kirsch, Roxanne

    2016-01-01

    The purpose of this review is to discuss the management of the low cardiac output syndrome (LCOS) following surgery for congenital heart disease. The LCOS is a well-recognized, frequent post-operative complication with an accepted collection of hemodynamic and physiologic aberrations. Approximately 25% of children experience a decrease in cardiac index of less than 2 L/min/m2 within 6-18 hours after cardiac surgery. Post-operative strategies that may be used to manage patients as risk for or in a state of low cardiac output include the use of hemodynamic monitoring, enabling a timely and accurate assessment of cardiovascular function and tissue oxygenation; optimization of ventricular loading conditions; the judicious use of inotropic agents; an appreciation of and the utilization of positive pressure ventilation for circulatory support; and, in some circumstances, mechanical circulatory support. All interventions and strategies should culminate in improving the relationship between oxygen supply and demand, ensuring adequate tissue oxygenation. PMID:26585039

  20. Valve area and cardiac output in aortic stenosis: quantification by magnetic resonance velocity mapping

    DEFF Research Database (Denmark)

    Søndergaard, Lise; Hildebrandt, P; Lindvig, K;

    1993-01-01

    Valve area and cardiac output were determined with magnetic resonance (MR) velocity mapping in 12 patients with aortic stenosis. Heart catheterization, Doppler echocardiography, and indicator dilution were performed for comparison. Left ventricle could be catheterized in only nine patients; in...... material, MR measured a mean area of 1.1 cm2 compared with 1.2 cm2 derived from Doppler echocardiography data, with a mean difference of 0.1 cm2 and [-0.5, +0.6] cm2 as limits of agreement. In 11 patients the cardiac output was quantified by MR to a mean of 4.9 L/min and by indicator dilution to 5.0 L......--the valvular area and the cardiac output--may be quantified, MR has potential to become a clinical tool in assessment of severity in aortic stenosis....

  1. Constant infusion transpulmonary thermodilution for the assessment of cardiac output in exercising humans

    DEFF Research Database (Denmark)

    Calbet, J A L; Mortensen, Stefan; Munch, G D W;

    2016-01-01

    To determine the accuracy and precision of constant infusion transpulmonary thermodilution cardiac output (CITT-Q) assessment during exercise in humans, using indocyanine green (ICG) dilution and bolus transpulmonary thermodilution (BTD) as reference methods, cardiac output (Q) was determined at...... rest and during incremental one- and two-legged pedaling on a cycle ergometer, and combined arm cranking with leg pedaling to exhaustion in 15 healthy men. Continuous infusions of iced saline in the femoral vein (n = 41) or simultaneously in the femoral and axillary (n = 66) veins with determination of......: 6.1-11.1%). In conclusion, cardiac output can be precisely and accurately determined with constant infusion transpulmonary thermodilution in exercising humans....

  2. Techniques of cardiac output measurement during liver transplantation: arterial pulse wave versus thermodilution

    DEFF Research Database (Denmark)

    Nissen, P.; Lieshout, J.J. van; Novovic, S.;

    2009-01-01

    In this study, we compared continuous cardiac output (CO) obtained from the femoral arterial pressure by simulation of an aortic input impedance model [model-simulated cardiac output (MCO)] to thermodilution cardiac output (TDCO) determined by bolus injection during liver transplantation. Both...... variables were measured in 39 adult patients (13 females) every 10th minute during liver transplant surgery. Paired measurements were compared during the 4 phases of surgery-dissection, anhepatic phase, early reperfusion (the first 15 minutes after reperfusion), and late reperfusion (15-60 minutes after......, and the mutual correlation coefficient was 0.812 (P < 0.001). This study indicates that during liver transplantation surgery, MCO reflects TDCO throughout the operation. Thus, for CO, this less invasive method appears to provide a reliable uninterrupted measurement during orthotopic liver...

  3. Cardiac output determined by echocardiography in patients with cirrhosis: comparison with the indicator dilution technique

    DEFF Research Database (Denmark)

    Andersen, Ulrik B; Møller, Søren; Bendtsen, Flemming; Henriksen, Jens H

    2003-01-01

    technique (CO(I)). METHODS: Twelve patients with cirrhosis were studied. CO(d) was measured as the spatial mean velocity of the left ventricular outflow tract, multiplied by the cross-sectional area and the heart rate. CO(I) was determined by the standard indicator dilution technique after injection of 125I......BACKGROUND/AIMS: Measurement of cardiac output in hyperkinetic patients with cirrhosis by Doppler echocardiography is increasingly reported, but has not been validated. We have compared simultaneous measurements of cardiac output by Doppler echocardiography (CO(d)) and by the indicator dilution...... with the Doppler technique. CONCLUSION: Doppler measurements of cardiac output in groups of patients with cirrhosis are accurate with respect to the group mean, but marked disagreements of over- and underestimation were seen in individual patients. The reproducibility of the Doppler technique is...

  4. Measurement of cardiac output by dynamic computed transmission tomography. Comparison with thermodilution method

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Yoshiaki; Yoshino, Futoshi; Ootani, Yukihiro; Kishimoto, Kinya; Takahashi, Ryuji

    1989-05-01

    The capacity of the new computed tomography (CT) instrument with excellent time resolution to measure cardiac output was explored. Dynamic scans of serial one-second images were performed at the middle section of left ventricle for 28 sec. We injected a bolus of 0.3 ml/kg angiografin for 2 sec or 0.4 ml/kg angiografin for 4 sec into the inferior vena cava. The regions of interest were set in the left ventricular cavity and thoracic aorta. Cardiac output was calculated by applying indicator dilution principles. The results were compared with those obtained by thermodilution. The CT results by using 2 sec 0.3 ml/kg angiografin correlated well (r=0.91, p<0.001) with those of thermodilution. This study indicates the utililty of dynamic CT for estimation of cardiac output. (author).

  5. Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners

    OpenAIRE

    Billat, Véronique L.; Hélène Petot; Morgan Landrain; Renaud Meilland; Jean Pierre Koralsztein; Laurence Mille-Hamard

    2012-01-01

    Purpose. Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). Methods. We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maxima...

  6. Cardiac output determination during intravenous cardioangiography using X-ray fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Boijsen, M.; Goss, F.; Jacobsson, L.; Lamm, C.; Schlossmann, D.; Bjoerneld, L.; Tylen, U.

    Cardiac output was determined with an indicator dilution technique during digital venous angiography of the left ventricle in 11 patients. The contrast medium injected into the right atrium was used as indicator. During and after the injection of contrast medium one blood sample per second was obtained through a catheter placed in the descending aorta. The samples were analyzed for iodine content with X-ray fluorescence analysis and cardiac output determined ad modum Stewart-Hamilton. Thermodilution was used as a reference method. The results indicate that the indicator dilution method with the use of contrast medium might be used for calibration of videodensitometric methods for blood flow measurements.

  7. Dye-dilution cardiac output without blood withdrawal in the conscious rabbit

    International Nuclear Information System (INIS)

    Cardiac output can be measured in the conscious rabbit without blood withdrawal by use of a modified dye-dilution method. Blood flows continuously from the central ear artery through a Silastic catheter that passes through a modified cuvette lumen and back into an ear vein. Blood flow through this shunt was 1.5 ml/min. This modified technique was evaluated by comparison with a simultaneously performed cardiac output measurement using radioactive microspheres and by making consecutive dye-dilution measurements at short time intervals. A correlation coefficient of 0.96 was obtained when comparing dye-dilution and microsphere cardiac outputs. The difference between 11 paired measurements was 7.09 +- 5.24% (mean +- SD). Consecutive outputs measured within 3 min of each other by the flow-through technique had a correlation coefficient of 0.99 and a difference between the first and second determinations of 3.52 +- 2.38%. The method permits dye-dilution cardiac output measurement in the conscious rabbit while avoiding the potential error caused by blood withdrawal from small animals

  8. Is pulmonary gas exchange during exercise in hypoxia impaired with the increase of cardiac output?

    DEFF Research Database (Denmark)

    Calbet, J.A.; Robach, P.; Lundby, C.;

    2008-01-01

    diffusion with increases in exercise intensity. We have consistently observed that during steady-state, submaximal (100-120 W) exercise on the cycle ergometer in hypoxia the lung can accommodate an increase in cardiac output of approximately 2 L x min(-1) without any significant effect on pulmonary gas......During exercise in humans, the alveolar-arterial O(2) tension difference ((A-a)DO(2)) increases with exercise intensity and is an important factor determining the absolute level of oxygen binding to hemoglobin and therefore the level of systemic oxygen transport. During exercise in hypoxia, the (A......-a)DO(2) is accentuated. Using the multiple inert gas elimination technique it has been shown that during exercise in acute hypoxia the contribution of ventilation-perfusion inequality to (A-a)DO(2) is rather small and in the absence of pulmonary edema intrapulmonary shunts can be ruled out. This implies...

  9. Robust output control for discrete uncertain systems

    International Nuclear Information System (INIS)

    This work deals with the problem of output robust stabilization of uncertain discrete systems with matched uncertainties. In the continuous case, the problem of the existence of an output min-max controller for systems with matched uncertainties was treated extensively and has been fully resolved. It was shown that an output min-max controller exists if and only if there exists a feedback gain matrix that makes the nominal system strictly positive real. It was found that if the system is minimum phase and has a high frequency gain with a full column rank, then there exists an output controller that makes the system. These results have motivated this work that presents a comprehensive solution to the problem of the existence of an output discrete min-max controller (static and dynamic) for multiple input multiple output systems which can be stabilized and are detectable. The question of the existence of an output feedback gain, K, that assures that for the resulting closed loop there exists a static output LMMC is investigated. For square systems an extremely simple criterion is derived. For non square systems, the condition involves searching for the matrix W that assures that asymptotically stabilized the system. Conditions for the existence of a static output RMMC are also investigated. 44 refs

  10. Performance of a new pulse contour method for continuous cardiac output monitoring: validation in critically ill patients

    OpenAIRE

    Bendjelid, Karim; Marx, G.; Kiefer, N.; Simon, T P; Geisen, M; Hoeft, A.; Siegenthaler, Nils; Hofer, C K

    2013-01-01

    BACKGROUND: /st>A new calibrated pulse wave analysis method (VolumeView™/EV1000™, Edwards Lifesciences, Irvine, CA, USA) has been developed to continuously monitor cardiac output (CO). The aim of this study was to compare the performance of the VolumeView method, and of the PiCCO2™ pulse contour method (Pulsion Medical Systems, Munich, Germany), with reference transpulmonary thermodilution (TPTD) CO measurements. METHODS: /st>This was a prospective, multicentre observational study performed i...

  11. Rowing increases stroke volume and cardiac output to a greater extent than cycling

    Czech Academy of Sciences Publication Activity Database

    Horn, P.; Ošťádal, P.; Ošťádal, Bohuslav

    2015-01-01

    Roč. 64, č. 2 (2015), s. 203-207. ISSN 0862-8408 Institutional support: RVO:67985823 Keywords : cardiac output * cycling * heart rate * stroke volume Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.293, year: 2014

  12. Phlebotomy eliminates the maximal cardiac output response to six weeks of exercise training

    DEFF Research Database (Denmark)

    Bonne, Thomas Christian; Doucende, Gregory; Flück, Daniela;

    2014-01-01

    With this study we tested the hypothesis that six weeks of endurance training increases maximal cardiac output (Qmax) relatively more by elevating blood volume (BV) than by inducing structural and functional changes within the heart. Nine healthy but untrained volunteers (VO2max 47 ± 5 ml.min(-1)...

  13. Effects of levosimendan for low cardiac output syndrome in critically ill patients

    DEFF Research Database (Denmark)

    Koster, Geert; Wetterslev, Jørn; Gluud, Christian;

    2015-01-01

    PURPOSE: To assess the benefits and harms of levosimendan for low cardiac output syndrome in critically ill patients. METHODS: We conducted a systematic review with meta-analyses and trial sequential analyses (TSA) of randomised clinical trials comparing levosimendan with any type of control. Two...

  14. A-V Delay Versus Cardiac Output Measured with Thorax Bioimpedance Monitor

    Czech Academy of Sciences Publication Activity Database

    Vondra, Vlastimil; Halámek, Josef; Viščor, Ivo; Jurák, Pavel; Novák, M.; Lipoldová, J.

    2008-01-01

    Roč. 6, č. 1 (2008), s. 73. ISSN 1556-7451. [World Congress on Heart Disease /14./. 26.07.2008-29.07.2008, Toronto] Institutional research plan: CEZ:AV0Z20650511 Keywords : atrio-ventricular delay * resynchronization therapy * impedance cardiography * cardiac output Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  15. Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

    DEFF Research Database (Denmark)

    Schytz, Philip Andreas; Mace, Maria Lerche; Soja, Anne Merete Boas;

    2015-01-01

    reducing EBFR on BP exists and data are conflicting. The aim of this study was to evaluate the effect and the potential mechanism(s) involved by investigating the impact of changes in EBFR on BP, pulse rate (PR) and cardiac output (CO) in HD patients with arteriovenous-fistulas (AV-fistulas). METHODS: We...

  16. Effect of region of interest selection on first-pass radionuclide cardiac output determination

    International Nuclear Information System (INIS)

    In principle, region of interest (ROI) selection should not affect the measurement of cardiac output by the first-pass technique with a radioactive intravascular indicator. Clinical application of the method requires that this theoretical hypothesis be tested. Sixty-eight left anterior oblique first-pass studies were acquired with a scintillation camera and computer using red blood cells labeled in vitro with /sup 99m/Tc. Calculated mean cardiac output varied in the following order with respect to ROI: lung greater than right heart greater than left ventricle greater than whole heart (both ventricles) greater than aorta. Similar variations were observed in patients both with and without valvular regurgitation. Regions of interest over left ventricle or whole heart yielded the best correlations with cardiac output by thermodilution (r = 0.96, 0.95, respectively, n = 28) as well as the smallest interobserver variations (r = 0.994, 0.995, respectively, n = 33). First-pass studies with [/sup 99m/Tc]red blood cells labeled in vitro can yield accurate, reproducible determinations of cardiac output provided that the effect of ROI selection is recognized and that regions are properly selected

  17. Assessment of cardiac output with transpulmonary thermodilution during exercise in humans

    DEFF Research Database (Denmark)

    Calbet, José A L; Boushel, Robert

    2015-01-01

    The accuracy and reproducibility of transpulmonary thermodilution (TPTd) to assess cardiac output (Q̇) in exercising men was determined using indocyanine green (ICG) dilution as a reference method. TPTd has been utilized for the assessment of Q̇ and preload indexes of global end-diastolic volume...

  18. Effect of region of interest selection on first-pass radionuclide cardiac output determination

    Energy Technology Data Exchange (ETDEWEB)

    Glass, E.C.; Rahimian, J.; Hines, H.H.

    1986-08-01

    In principle, region of interest (ROI) selection should not affect the measurement of cardiac output by the first-pass technique with a radioactive intravascular indicator. Clinical application of the method requires that this theoretical hypothesis be tested. Sixty-eight left anterior oblique first-pass studies were acquired with a scintillation camera and computer using red blood cells labeled in vitro with /sup 99m/Tc. Calculated mean cardiac output varied in the following order with respect to ROI: lung greater than right heart greater than left ventricle greater than whole heart (both ventricles) greater than aorta. Similar variations were observed in patients both with and without valvular regurgitation. Regions of interest over left ventricle or whole heart yielded the best correlations with cardiac output by thermodilution (r = 0.96, 0.95, respectively, n = 28) as well as the smallest interobserver variations (r = 0.994, 0.995, respectively, n = 33). First-pass studies with (/sup 99m/Tc)red blood cells labeled in vitro can yield accurate, reproducible determinations of cardiac output provided that the effect of ROI selection is recognized and that regions are properly selected.

  19. A model to calculate cardiac output in hemodialysis patients by thermodilution

    Directory of Open Access Journals (Sweden)

    Alayoud Ahmed

    2012-06-01

    Full Text Available Abstract The Blood Temperature Monitor module (BTM is used to measure recirculation by thermodilution in dialysis. Numerous studies have confirmed its interest in the measuring of the vascular access flow. In this letter we describe a model to calculate cardiac output in dialysis by the BTM.

  20. Non-invasive measurements of cardiac output in atrial fibrillation: Inert gas rebreathing and impedance cardiography

    DEFF Research Database (Denmark)

    Osbak, Philip S; Henriksen, Jens Henrik Sahl; Kofoed, Klaus F;

    2011-01-01

    Abstract Background. Atrial fibrillation (AF) is associated with significant morbidity and mortality. To test the effect of interventions, knowledge of cardiac output (CO) is important. However, the irregular heart rate might cause some methods for determination of CO to have inherent weaknesses...

  1. Investigations concerning the application of the cross-correlation method in cardiac output measurements

    Directory of Open Access Journals (Sweden)

    Gawlikowski Maciej

    2012-05-01

    Full Text Available Abstract Background In spite of numerous non-invasive examinations the “gold clinical standard” of cardiac output measurements is the invasive pulmonary artery catheterization by means of the Swan-Ganz catheter and the application of the thermodilution method to estimate the blood flow. The results obtained by means of thermodilution are sensitive to many physical and biological disturbances. The unreliability of this method amounts to 20-45% and depends on the given variant of the method. Therefore some other method, more accurate and resistant to disturbances, was looked for. This paper presents a new approach to cardiac output measurements, based on cross-correlation signal analysis. The goal of investigations was to verify experimentally the application of the cross-correlation method of cardiac output measurements. Results In 99.2% of the examined cases the extreme of the cross-correlation function was easy to be estimated by numerical algorithms. In 0,8% of the remaining cases (with a plateau region adjacent to the maximum point numerical detection of the extreme was inaccurate. The typical unreliability of the investigated method amounted o 5.1% (9.8% in the worst case. Investigations performed on a physical model revealed that the unreliability of cardiac output measurements by means of the cross-correlation method is 3–5 times better than in the case of thermodilution. Conclusions The performed investigations and theoretical analysis have shown, that the cross-correlation method may be applied in cardiac output measurements. This kind of measurements seems to be more accurate and disturbance-resistant than clinically applied thermodilution.

  2. The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output

    DEFF Research Database (Denmark)

    Smerup, Morten Holdgaard; Damkjær, Mads; Brøndum, Emil; Baandrup, Ulrik T.; Kristiansen, Steen Buus; Nygaard, Hans; Aalkjær, Christian; Sauer, Cathrine; Buchanan, Rasmus; Bertelsen, Mads Frost; Østergaard, Kristine Hovkjær; Grøndahl, Carsten; Candy, Geoffrey; Hasenkam, J Michael; Secher, Niels H; Bie, Peter; Wang, Tobias

    2015-01-01

    pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min(-1), respectively...

  3. Non-invasive cardiac output trending during exercise recovery on a bathroom-scale-based ballistocardiograph

    International Nuclear Information System (INIS)

    Cardiac ejection of blood into the aorta generates a reaction force on the body that can be measured externally via the ballistocardiogram (BCG). In this study, a commercial bathroom scale was modified to measure the BCGs of nine healthy subjects recovering from treadmill exercise. During the recovery, Doppler echocardiogram signals were obtained simultaneously from the left ventricular outflow tract of the heart. The percentage changes in root-mean-square (RMS) power of the BCG were strongly correlated with the percentage changes in cardiac output measured by Doppler echocardiography (R2 = 0.85, n = 275 data points). The correlation coefficients for individually analyzed data ranged from 0.79 to 0.96. Using Bland–Altman methods for assessing agreement, the mean bias was found to be −0.5% (±24%) in estimating the percentage changes in cardiac output. In contrast to other non-invasive methods for trending cardiac output, the unobtrusive procedure presented here uses inexpensive equipment and could be performed without the aid of a medical professional

  4. Cardiac manifestations in systemic sclerosis

    Institute of Scientific and Technical Information of China (English)

    Sevdalina; Lambova

    2014-01-01

    Primary cardiac involvement, which develops as a direct consequence of systemic sclerosis(SSc), may manifest as myocardial damage, fibrosis of the conduction system, pericardial and, less frequently, as valvular disease. In addition, cardiac complications in SSc may develop as a secondary phenomenon due to pulmonary arterial hypertension and kidney pathology. The prevalence of primary cardiac involvement in SSc is variable and difficult to determine because of the diversity of cardiac manifestations, the presence of subclinical periods, the type of diagnostic tools applied, and the diversity of patient populations. When clinically manifested, cardiac involvement is thought to be an important prognostic factor. Profound microvascular disease is a pathognomonic feature of SSc, as both vasospasm and structural alterations are present. Such alterations are thought to predict macrovascular atherosclerosis over time. There are contradictory reports regarding the prevalence of atherosclerosis in SSc. According to some authors, the prevalence of atherosclerosis of the large epicardial coronary arteries is similar to that of the general population, in contrast with other rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, the level of inflammation in SSc is inferior. Thus, the atherosclerotic process may not be as aggressive and not easily detectable in smaller studies. Echocardiography(especially tissue Doppler imaging), single-photon emission computed tomography, magnetic resonance imaging and cardiac computed tomography are sensitive techniques for earlier detection of both structural and functional scleroderma-related cardiac pathologies. Screening for subclinical cardiac involvement via modern, sensitive tools provides an opportunity for early diagnosis and treatment, which is of crucial importance for a positive outcome.

  5. Initial Observations of the Effects of Calcium Chloride Infusions in Pediatric Patients with Low Cardiac Output.

    Science.gov (United States)

    Averin, Konstantin; Villa, Chet; Krawczeski, Catherine D; Pratt, Jesse; King, Eileen; Jefferies, John L; Nelson, David P; Cooper, David S; Ryan, Thomas D; Sawyer, Jaclyn; Towbin, Jeffrey A; Lorts, Angela

    2016-03-01

    Myocardial contractility and relaxation are highly dependent on calcium homeostasis. Immature myocardium, as in pediatric patients, is thought to be more dependent on extracellular calcium for optimal function. For this reason, intravenous calcium chloride infusions may improve myocardial function in the pediatric patient. The objectives of this study were to report the hemodynamic changes seen after administration of continuous calcium chloride to critically ill children. We retrospectively identified pediatric patients (newborn to 17 years old) with hemodynamic instability admitted to the cardiac ICU between May 2011 and May 2012 who received a continuous infusion of calcium chloride. The primary outcome was improvement in cardiac output, assessed by arterial-mixed venous oxygen saturation (A-V) difference. Sixty-eight patients, mean age 0.87 ± 2.67 years, received a total of 116 calcium infusions. Calcium chloride infusions resulted in significant improvements in primary and secondary measures of cardiac output at 2 and 6 h. Six hours after calcium initiation, A-V oxygen saturation difference decreased by 7.4 % (32.6 ± 2.1 to 25.2 ± 2.0 %, p HR (149.1 vs 145.6 bpm p = 0.07). Urine output increased 0.66 ml/kg/h in the 8-h period after calcium initiation when compared to pre-initiation (p = 0.003). Neonates had the strongest evidence of effectiveness with other age groups trending toward significance. Calcium chloride infusions improve markers of cardiac output in a heterogenous group of pediatric patients in a cardiac ICU. Neonates appear to derive the most benefit from utilization of these infusions. PMID:26687150

  6. Estimating changes in cardiac output using an implanted hemodynamic monitor in heart failure patients

    DEFF Research Database (Denmark)

    Ståhlberg, Marcus; Damgaard, Morten; Ersgård, David;

    2010-01-01

    OBJECTIVES: The aim of this study was to evaluate an algorithm that estimates changes in cardiac output (CO) from right ventricular (RV) pressure waveforms derived from an implantable hemodynamic monitor (IHM) in heart failure patients. DESIGN: Twelve heart failure patients (NYHA II-III, EF 32......%) with an implantable hemodynamic monitor (Chronicle) were included in this study. Changes in cardiac output were provoked by body position change at rest (left lateral supine, horizontal supine, sitting, and standing) and a steady state bicycle exercise at 20 watts. Estimated CO derived from the IHM (CO(IHM......)) was compared to CO measured with inert gas rebreathing (CO(RB)), echocardiography (CO(ECHO)) and impedance cardiography (CO(ICG)). CO(RB) was considered the reference method. RESULTS: The median intra-patient correlation coefficient comparing CO(RB) and CO(IHM) was 0.83 (range: 0.63-0.98). Comparing...

  7. Comparative radionuclide and thermodilution determinations of cardiac output and stroke volume in the baboon (Papio ursinus)

    Energy Technology Data Exchange (ETDEWEB)

    Dormehl, I.C.; Bosman, H.; Hugo, N.; Maree, M.; van Vuuren, C.; van Zandwyk, C.; van Aswegen, A.; Paterson, L.

    1987-01-01

    Thermodilution cardiac output determinations and multigated equilibrium blood-pool scintigraphy were performed in ten healthy chacma baboons (Papio ursinus). The correlation was moderately good between both the radionuclide and thermodilution stroke volume (r = 0.58, SEE = 3 ml; SVth = 0.78SVr + 15.6 ml) as well as the cardiac output (r = 0.72, SEE = 0.2 liter/min; COth = 0.56 Cor + 2.1 liter/min). The attenuation depth dr as determined by radionuclide techniques was found to correlate well with the radiologically determined values dx (r = 0.8, SEE = 0.4 cm; dx = 0.87dr + 0.72 cm) which validated the depth values used in the calculations.

  8. Pulmonary artery pressure responses to increased cardiac output in chickens with raised metabolic rate

    OpenAIRE

    West, John B.; Fu, Zhenxing; Gu, Yusu; Wagner, Harrieth E.; Carr, J. Austin; Peterson, Kirk L.

    2010-01-01

    Previous work has shown remarkable differences in the pressure-flow relations of the pulmonary circulation between birds and mammals. For example several studies suggest that the avian pulmonary blood vessels behave like rigid tubes, very different from the situation in mammalian lung. We therefore speculated that birds would develop high pulmonary artery pressures when the cardiac output was substantially increased during heavy exercise, for example during flight. However because of the tech...

  9. Hereditary Hemorrhagic Telangiectasia Presenting as High Output Cardiac Failure during Pregnancy

    OpenAIRE

    Tareq Goussous; Alex Haynes; Katherine Najarian; Marcos Daccarett; Shukri David

    2009-01-01

    High-output cardiac failure secondary to hepatic involvement is a rare complication of hereditary hemorrhagic telangiectasia (HHT). Here we report a 43-year-old woman who presented at 29 weeks gestation of her second pregnancy with complications of right-sided heart failure and preterm labor. After delivery via cesarean section, the patient was found to have intrahepatic arteriovenous malformations through non-invasive imaging. Subsequently, a family history of vascular malformations and epis...

  10. The Unpredictable Effect of Changing Cardiac Output on Hypoxemia after Acute Pulmonary Thromboembolism

    OpenAIRE

    Tsang, John Y.C.; Wayne J E Lamm; Blazej Neradilek; Polissar, Nayak L.; Michael P. Hlastala

    2008-01-01

    Previous studies reported that the degree of hypoxemia following acute pulmonary thromboembolism (APTE) was highly variable and that its mechanism was mainly due to the creation of many high and low ventilation/perfusion (V/Q) units, as a result of the heterogeneous regional blood flow (Q) caused by embolic obstruction. We studied the effect of changing cardiac output (Qt) on gas exchange after APTE in 5 embolized piglets (23 ± 3 Kg), using Dobutamine intermittently at approximately 20 µg/kg/...

  11. Multisite Tissue Oxygenation Monitoring Indicates Organ-Specific Flow Distribution and Oxygen Delivery Related to Low Cardiac Output in Preterm Infants With Clinical Sepsis

    NARCIS (Netherlands)

    van der Laan, Michelle E; Roofthooft, Marc; Fries, Marian W A; Schat, Trijntje E; Bos, Arend F; Berger, Rolf M F; Kooi, Elisabeth M W

    2016-01-01

    OBJECTIVES: Cardiac output may be compromised in preterm infants with sepsis. Whether low cardiac output is associated with low tissue oxygen supply in these patients is unclear. The aim of the current study was to assess the association between cardiac output, assessed by echocardiography, and tiss

  12. The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia

    OpenAIRE

    Duck Shin, Young; Hoon Yim, Kyoung; Hi Park, Sang; Wook Jeon, Yong; Ho Bae, Jin; Soo Lee, Tae; Hwan Kim, Myoung; Jin Choi, Young

    2014-01-01

    Objective: The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal steth...

  13. Lack of agreement between bioimpedance and continuous thermodilution measurement of cardiac output in intensive care unit patients

    OpenAIRE

    Barry, Ben N; Mallick, Abhiram; Bodenham, Andrew R; Vucevic, Michael

    1997-01-01

    Background: Bolus thermodilution is the standard bedside method of cardiac output measurement in the intensive care unit (ICU). The Baxter Vigilance monitor uses a modified thermodilution pulmonary artery catheter with a thermal filament to give a continuous read-out of cardiac output. This has been shown to correlate very well with both the 'gold standard' dye dilution method and the bolus thermodilution method. Bioimpedance cardiography using the Bomed NCCOM 3 offers a noninvasive means of ...

  14. Regional blood flow distribution in dog during induced hypotension and low cardiac output. Spontaneous breathing versus artificial ventilation.

    OpenAIRE

    Viires, N; Sillye, G; Aubier, M.; Rassidakis, A; Roussos, C

    1983-01-01

    Respiratory muscle blood flow and organ blood flow was studied in two groups of dogs with radioactively labeled microspheres to assess the influence of the working respiratory muscles on the regional distribution of blood flow when arterial pressure and cardiac output were lowered by pericardial tamponade. In one group (n = 6), the dogs were paralyzed and mechanically ventilated (Mv), while in the other (n = 6), they were left to breathe spontaneously (Sb). Cardiac output fell to 30% of contr...

  15. A prospective study to evaluate the accuracy of pulse power analysis to monitor cardiac output in critically ill patients

    OpenAIRE

    Grounds R Michael; Fawcett Jayne; Cecconi Maurizio; Rhodes Andrew

    2008-01-01

    Abstract Background Intermittent measurement of cardiac output may be performed using a lithium dilution technique (LiDCO). This can then be used to calibrate a pulse power algorithm of the arterial waveform which provides a continuous estimate of this variable. The purpose of this study was to examine the duration of accuracy of the pulse power algorithm in critically ill patients with respect to time when compared to measurements of cardiac output by an independent technique. Methods Pulse ...

  16. At high cardiac output, diesel exhaust exposure increases pulmonary vascular resistance and decreases distensibility of pulmonary resistive vessels.

    Science.gov (United States)

    Wauters, Aurélien; Vicenzi, Marco; De Becker, Benjamin; Riga, Jean-Philippe; Esmaeilzadeh, Fatemeh; Faoro, Vitalie; Vachiéry, Jean-Luc; van de Borne, Philippe; Argacha, Jean-François

    2015-12-15

    Air pollution has recently been associated with the development of acute decompensated heart failure, but the underlying biological mechanisms remain unclear. A pulmonary vasoconstrictor effect of air pollution, combined with its systemic effects, may precipitate decompensated heart failure. The aim of the present study was to investigate the effects of acute exposure to diesel exhaust (DE) on pulmonary vascular resistance (PVR) under resting and stress conditions but also to determine whether air pollution may potentiate acquired pulmonary hypertension. Eighteen healthy male volunteers were exposed to ambient air (AA) or dilute DE with a particulate matter of effects of DE on PVR, on the coefficient of distensibilty of pulmonary vessels (α), and on right and left ventricular function were evaluated at rest (n = 18), during dobutamine stress echocardiography (n = 10), and during exercise stress echocardiography performed in hypoxia (n = 8). Serum endothelin-1 and fractional exhaled nitric oxide were also measured. At rest, exposure to DE did not affect PVR. During dobutamine stress, the slope of the mean pulmonary artery pressure-cardiac output relationship increased from 2.8 ± 0.5 mmHg · min · l (-1) in AA to 3.9 ± 0.5 mmHg · min · l (-1) in DE (P hypoxia-related upper shift of the mean pulmonary artery pressure-cardiac output relationship. Exposure to DE did not affect serum endothelin-1 concentration or fractional exhaled nitric oxide. In conclusion, acute exposure to DE increased pulmonary vasomotor tone by decreasing the distensibility of pulmonary resistive vessels at high cardiac output. PMID:26497960

  17. Determination of cardiac output, tissue blood flow, volume and lipid content in Sprague-Dawley rats

    International Nuclear Information System (INIS)

    One critical aspect of physiologically-based pharmacokinetic (PBPK) model development is the choice of values for organ blood flows, cardiac output and tissue volumes for input into models. These values vary depending upon the strain, size, age, and sex of animal for which a PBPK model is being developed. Tissue blood flows, cardiac output, tissue volume, and lipid content were determined in male S-D rats, (350-375 g, N=8). A radiolabel microsphere method utilizing Scandium (46Sc), Tin (113Sn),and Gadolinium (153Gd) was used to determine blood flow. Each rat received 3 radiolabeled injections. After the third injection, animals were sacrificed, and radioactivity in each tissue was determined in a 3-channel gamma counter. Tissues sampled include brain, heart, kidneys, liver, lungs, spleen, pancreas, adrenals, stomach, intestines, colon, testis, bone and skeletal muscle. Cardiac output was 142 ml/min. Blood flow values for eliminating organs were 0.49 (liver), 16.52 (kidney), and 1.77 (lung) ml/min/g tissue. Tissues which had significantly increased blood flow during the dark cycle included femur, abdonimal fat, triceps brachii and abdominal muscles, stomach, spleen and lung. Dissectable fat, organ volume, and organ lipid content were determined in a separate group of rats (N= 8). Volume and lipid content were determined for the same tissues as blood flow. Body fat was 7.35% of bw and extractable lipid content of eliminating organs was 42.3 (liver), 43.4 (kidney), and 35.9 (lung) mg/g tissue. Precise measurements should improve the accuracy of PBPK model predictions, and therfore help in reducing uncertainites in risk assessment of volatile organics and other pollutnats

  18. Continuous versus bolus cardiac output monitoring during or thotopic liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Fang-Ping Bao; Jian Wu

    2008-01-01

    BACKGROUND: Cardiac output monitoring is important for critical patients. This study aimed to determine the delayed response of continuous cardiac output (CCO) thermodilution measurement, whether CCO and bolus cardiac output (BCO) thermodilution agree sufifciently to be used interchangeably, and whether CCO monitoring is reliable for patients undergoing liver transplantation. METHODS:Thirteen patients undergoing liver transplan-tation without veno-venous bypass were studied (37-66 years old, weight 46-75 kg). Continuous and bolus thermodilution measurements were performed at predeifned time points using an "Opti-Q" SvO2/CCO monitor (Abbott Laboratories, North Chicago, IL, USA). Bias and 95% limits of agreement were calculated according to Bland and Altman analysis. The limits of agreement by which two methods are judged to be interchangeable were deifned in advance as ±(13%× BCOmean) L/min. The repeatability and relative error of CCO, and the differences between CCO and the mean of the two measurements were calculated. RESULTS:Cardiac output measurements yielded 196 data pairs with ranges of 1.9 to 17.9 L/min for CCO and 2.1 to 18.3 L/min for BCO. The response time of CCO was delayed in the early phases after caval clamping and after reperfusion. At most of the measurement points, bias and 95%limits of agreement were-0.18±1.91 L/min. 95%limits of agreement did not fall within the predetermined limits of agreement of ±1.14 L/min. The repeatability coefifcient of CCO was 0.36 L/min and the relative error was 4.6±4.7%. The mean difference between CCO and the average of the two methods was-0.09 L/min (0.49 L/min). CONCLUSIONS:In patients undergoing liver transplan-tation, the delayed response of CCO limits its application during the early phases after caval clamping and after reperfusion of the graft. The two methods are not interchangeable even in hemodynamic stability. Continuous thermodilution monitoring, however, is reliable or acceptable for clinical purposes.

  19. Changes in Heart Rate in Patients with a Pacemaker do not Affect Cardiac Output

    Czech Academy of Sciences Publication Activity Database

    Vondra, Vlastimil; Soukup, L.; Jurák, Pavel; Halámek, Josef; Viščor, Ivo; Lipoldová, J.; Leinveber, Pavel

    Piscataway : IEEE, 2012, s. 511. ISBN 978-1-4244-4119-8. [EMBC 2012. Annual International Conference of the IEEE Engineering in Medicine and Biology Society /34./. San Diego (US), 28.08.2012-01.09.2012] R&D Projects: GA MŠk ME09050; GA MŠk ED0017/01/01; GA ČR GAP102/12/2034 Institutional support: RVO:68081731 Keywords : Pacemaker * Changes in Heart Rate * Cardiac Output Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  20. Hereditary Hemorrhagic Telangiectasia Presenting as High Output Cardiac Failure during Pregnancy

    Directory of Open Access Journals (Sweden)

    Tareq Goussous

    2009-01-01

    Full Text Available High-output cardiac failure secondary to hepatic involvement is a rare complication of hereditary hemorrhagic telangiectasia (HHT. Here we report a 43-year-old woman who presented at 29 weeks gestation of her second pregnancy with complications of right-sided heart failure and preterm labor. After delivery via cesarean section, the patient was found to have intrahepatic arteriovenous malformations through non-invasive imaging. Subsequently, a family history of vascular malformations and epistaxis was elucidated and a diagnosis of HHT was made. This case is presented, along with a review of the literature and discussion of hepatic involvement in HHT with particular focus on the pregnant patient.

  1. Estimation of cardiac output by first-pass transit of radiotracers

    International Nuclear Information System (INIS)

    To evaluate cardiac function with various tracers to be used for radionuclide scintigraphy, we examined the validity of a simplified method to measure cardiac output (CO) by modifying the equation of Stewart-Hamilton in the radionuclide study. After a bolus injection of I-123 or Tc-99m tracer, the total injection dose and count in the pulmonary artery during the first transit of the tracer were measured to calculate the CO Index. The CO Index was obtained from the integral of the first transit of radiotracers in the pulmonary artery divided by the total injected count. CO was estimated from the regression formula which was obtained by comparing the CO Index with CO measured by the Doppler echocardiographic method. There were close correlations between the CO Index and CO measured by Doppler echocardiography both in the study with I-123 (n=13, r=0.85, p0.634 for I-123 and CO=3.18 x (CO Index)0.518 for Tc-99m). CO measured by this method is useful for the assessment of cardiac function with various tracers in routine clinical studies, and this simple method may be utilized for assessment of organ blood flow on the basis of the microsphere model. (author)

  2. Increasing cardiac output and decreasing oxygenation sequence in pump twins of acardiac twin pregnancies

    International Nuclear Information System (INIS)

    An acardiac twin pregnancy is a rare but serious complication of monochorionic twinning and consists of an acardiac twin and a pump twin. The acardiac twin is a severely malformed fetus that lacks most organs, particularly a heart, but grows during pregnancy because it is perfused by the developmentally normal pump twin via a set of arterioarterial and venovenous placental anastomoses. Pump twins die intrauterine or neonatally in about 50% of the cases. Because the effects of an acardiac mass on the pump twin's development are incompletely known, methods for outcome prognosis are currently not available. We sought to derive simple relations for the pump twin's excess cardiac output and decreased oxygenation and to use available clinical cases for a preliminary test of the model. As a method, we used a theoretical flow model to represent the fetoplacental circulation of an acardiac twin pregnancy and estimated blood deoxygenation and reoxygenation following perfusion of the two bodies and placentas, respectively. The results show the pump twin's excess cardiac output and decrease of venous oxygen saturation to depend on the ratio of pump twin to acardiac twin umbilical blood flow, whose ratio can be measured by ultrasonography. The clinical cases show a decreasing umbilical flow ratio with gestation. In conclusion, prospective serial study is necessary to test whether measurement of umbilical flow ratios allows monitoring the pump twin's pathophysiologic development, possibly resulting in a guideline for prognosis of pump twin survival. (note)

  3. Increasing cardiac output and decreasing oxygenation sequence in pump twins of acardiac twin pregnancies

    Energy Technology Data Exchange (ETDEWEB)

    Gemert, Martin J C van [Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Umur, Asli [Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); Wijngaard, Jeroen P H M van den [Laser Center and Department of Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam (Netherlands); VanBavel, Ed [Department of Medical Physics, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Vandenbussche, Frank P H A [Department of Obstetrics, Leiden University Medical Center, Leiden (Netherlands); Nikkels, Peter G J [Department of Pathology, University Medical Center, Utrecht (Netherlands)

    2005-02-07

    An acardiac twin pregnancy is a rare but serious complication of monochorionic twinning and consists of an acardiac twin and a pump twin. The acardiac twin is a severely malformed fetus that lacks most organs, particularly a heart, but grows during pregnancy because it is perfused by the developmentally normal pump twin via a set of arterioarterial and venovenous placental anastomoses. Pump twins die intrauterine or neonatally in about 50% of the cases. Because the effects of an acardiac mass on the pump twin's development are incompletely known, methods for outcome prognosis are currently not available. We sought to derive simple relations for the pump twin's excess cardiac output and decreased oxygenation and to use available clinical cases for a preliminary test of the model. As a method, we used a theoretical flow model to represent the fetoplacental circulation of an acardiac twin pregnancy and estimated blood deoxygenation and reoxygenation following perfusion of the two bodies and placentas, respectively. The results show the pump twin's excess cardiac output and decrease of venous oxygen saturation to depend on the ratio of pump twin to acardiac twin umbilical blood flow, whose ratio can be measured by ultrasonography. The clinical cases show a decreasing umbilical flow ratio with gestation. In conclusion, prospective serial study is necessary to test whether measurement of umbilical flow ratios allows monitoring the pump twin's pathophysiologic development, possibly resulting in a guideline for prognosis of pump twin survival. (note)

  4. Reliability of first-pass radionuclide determination of cardiac output in the upright position at rest and during exercise

    Energy Technology Data Exchange (ETDEWEB)

    Kelbaek, H.; Gjoerup, T.; Hvid-Jacobsen, K.; Skagen, K.; Munck, O. (Herlev Hospital (Denmark). Dept. of Clinical Physiology and Nuclear Medicine); Godtfredsen, J. (Herlev Hospital (Denmark). Dept. of Cardiology); Heslet, L. (Herlev Hospital (Denmark). Dept. of Anesthesiology); Tjur, T.; Jensen, A.M. (Copenhagen Univ. (Denmark). Inst. for Mathematical Statistics)

    1992-11-01

    The reliability of non-invasive determination of cardiac output using first-pass radionuclide cardiography at rest and during exercise in the upright position was evaluated in 20 patients with coronary artery disease. Cardiac output values ranged from 2.97 to 5.99 l/min at rest and from 5.08 to 10.82 l/min during exercise. Cardiac output results obtained by the radionuclide method were compared with those derived from the thermodilution technique performed simultaneously. The mean difference between the two techniques was 0.02/l min at rest and -0.34 l/min during exercise; the limits of agreement (mean {+-}1.96 SD) were -1.29 to 1.33 l/min and -1.97 to 1.29 l/min, respectively, indicating an acceptable level of agreement. A high reproducibility of the radionuclide technique was found, with a mean difference between determinations by two observers of 0.03 l/min at rest and 0.21 l/min during exercise, the corresponding limits of agreement being -0.75 to 0.81 l/min and -0.79 to 1.21 l/min, respectively. With the aid of a variance component analysis of two determinations by each of four observers, 95% confidence intervals of {+-}10% at rest at {+-}12% during exercise were computed for the radionuclide cardiac output measurements. The observer variation was most pronounced for the part of the cardiac output determination related to measurement of left ventricular equilibrium activity during exercise. First-pass radionuclide cardiography is a reliable method for determination of cardiac output in cardiac patients at rest and during exercise in the upright position. (orig.).

  5. Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration

    Directory of Open Access Journals (Sweden)

    Amann Matthias

    2007-11-01

    Full Text Available Abstract Background Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (COPAC measurement by the pulmonary artery catheter (PAC. However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (COAP device (FloTrac™, Vigileo™; Edwards Lifesciences, Irvine, CA, USA only requires access to the radial or femoral artery using a standard arterial catheter and does not need an external calibration. We validated this technique in critically ill patients in the intensive care unit (ICU using COPAC as the method of reference. Methods We studied 20 critically ill patients, aged 16 to 74 years (mean, 55.5 ± 18.8 years, who required both arterial and pulmonary artery pressure monitoring. COPAC measurements were performed at least every 4 hours and calculated as the average of 3 measurements, while COAP values were taken immediately at the end of bolus determinations. Accuracy of measurements was assessed by calculating the bias and limits of agreement using the method described by Bland and Altman. Results A total of 164 coupled measurements were obtained. Absolute values of COPAC ranged from 2.80 to 10.80 l/min (mean 5.93 ± 1.55 l/min. The bias and limits of agreement between COPAC and COAP for unequal numbers of replicates was 0.02 ± 2.92 l/min. The percentage error between COPAC and COAP was 49.3%. The bias between percentage changes in COPAC (ΔCOPAC and percentage changes in COAP (ΔCOAP for consecutive measurements was -0.70% ± 32.28%. COPAC and COAP showed a Pearson correlation coefficient of 0.58 (p PAC and ΔCOAP was 0.46 (p Conclusion Although the COAP algorithm shows a minimal bias with COPAC over a wide range of values in an inhomogeneous group of critically ill patients, the scattering of the data remains relative wide. Therefore, the used algorithm (V 1.03 failed to

  6. Cardiac Output and Stroke Volume at Anaerobic Threshold During Walking Exercise in Healthy Aged Subjects

    OpenAIRE

    Haga, Shukoh; Esaki, Kazuki; Toshinai, Kouji; Kinugasa, Takeshi; Takemasa, Toru; Ueya, Etsuo; Hamaoka, Takaumi; Katsumura, Toshihito; Kizaki, Takako; Ohno, Hideki

    2003-01-01

    HAGA, S., ESAKI, K., TOSHINAI, K., KINUGASA, T., TAKEMASA, T., UEYA, E., HAMAOKA, T., KATSUMURA, T., KIZAKI, t. and OHNO, H., Cardiac Output and Stroke Volume at Anaerobic Threshold During Walking Exercise in Healthy Aged Subjects. Abv. Exerc. Sports Physiol., Vol.9, No.1 pp.37-43, 2003. There have been few previous studies of cardiac outout for cardiovascular function at anaerobic threshold (AT) during walking exercise in healthy elderly subjects. The present study was performed to investiga...

  7. Reference values for total blood volume and cardiac output in humans

    Energy Technology Data Exchange (ETDEWEB)

    Williams, L.R. [Indiana Univ., South Bend, IN (United States). Division of Liberal Arts and Sciences

    1994-09-01

    Much research has been devoted to measurement of total blood volume (TBV) and cardiac output (CO) in humans but not enough effort has been devoted to collection and reduction of results for the purpose of deriving typical or {open_quotes}reference{close_quotes} values. Identification of normal values for TBV and CO is needed not only for clinical evaluations but also for the development of biokinetic models for ultra-short-lived radionuclides used in nuclear medicine (Leggett and Williams 1989). The purpose of this report is to offer reference values for TBV and CO, along with estimates of the associated uncertainties that arise from intra- and inter-subject variation, errors in measurement techniques, and other sources. Reference values are derived for basal supine CO and TBV in reference adult humans, and differences associated with age, sex, body size, body position, exercise, and other circumstances are discussed.

  8. Sildenafil improves cardiac output and exercise performance during acute hypoxia, but not normoxia.

    Science.gov (United States)

    Hsu, Andrew R; Barnholt, Kimberly E; Grundmann, Nicolas K; Lin, Joseph H; McCallum, Stewart W; Friedlander, Anne L

    2006-06-01

    Sildenafil causes pulmonary vasodilation, thus potentially reducing impairments of hypoxia-induced pulmonary hypertension on exercise performance at altitude. The purpose of this study was to determine the effects of sildenafil during normoxic and hypoxic exercise. We hypothesized that 1) sildenafil would have no significant effects on normoxic exercise, and 2) sildenafil would improve cardiac output, arterial oxygen saturation (SaO2), and performance during hypoxic exercise. Ten trained men performed one practice and three experimental trials at sea level (SL) and simulated high altitude (HA) of 3,874 m. Each cycling test consisted of a set-work-rate portion (55% work capacity: 1 h SL, 30 min HA) followed immediately by a time trial (10 km SL, 6 km HA). Double-blinded capsules (placebo, 50, or 100 mg) were taken 1 h before exercise in a randomly counterbalanced order. For HA, subjects also began breathing hypoxic gas (12.8% oxygen) 1 h before exercise. At SL, sildenafil had no effects on any cardiovascular or performance measures. At HA, sildenafil increased stroke volume (measured by impedance cardiography), cardiac output, and SaO2 during set-work-rate exercise. Sildenafil lowered 6-km time-trial time by 15% (P<0.05). SaO2 was also higher during the time trial (P<0.05) in response to sildenafil, despite higher work rates. Post hoc analyses revealed two subject groups, sildenafil responders and nonresponders, who improved time-trial performance by 39% (P<0.05) and 1.0%, respectively. No dose-response effects were observed. During cycling exercise in acute hypoxia, sildenafil can greatly improve cardiovascular function, SaO2, and performance for certain individuals. PMID:16455814

  9. Management of perioperative low cardiac output state without extracorporeal life support: What is feasible?

    Directory of Open Access Journals (Sweden)

    Kumar Girish

    2010-01-01

    Full Text Available A transient and reversible reduction in cardiac output-low cardiac output state (LCOS often occurs following surgery for congenital heart disease. Inappropriately managed LCOS is a risk factor for increased morbidity and death. LCOS may occasionally be progressive and refractory needing a period of "myocardial rest" with extracorporeal life support (ECLS. ECLS is currently considered a routine tool available for rapid deployment in most industrialized countries. Accumulated experience and refinements in technology have led to improving survivals - discharge survivals of 35%−50%, with almost 100% survival in select groups on elective left ventricular assist device. Thus, there is an increasing trend to initiate ECLS "early or electively in the operating room" in high-risk patients. India has a huge potential need for ECLS given the large number of infants presenting late with preexisting ventricular dysfunction or in circulatory collapse. ECLS is an expensive and resource consuming treatment modality and is not a viable therapeutic option in our country. The purpose of this paper is to reiterate an anticipatory, proactive approach to LCOS: (1 methods for early detection of evolving LCOS and (2 timely initiation of individualized therapy. This paper also explores what is feasible with the refinement of "simple, conventional, inexpensive strategies" for the management of LCOS. Therapy for LCOS should be multimodal based on the type of circulation and physiology. Our approach to LCOS includes: (1 intraoperative strategies, (2 aggressive afterload reduction, (3 lusitropy, (4 exclusion of structural defects, (5 harnessing cardiopulmonary interactions, and (6 addressing metabolic and endocrine abnormalities. We have achieved a discharge survival rate of greater than 97% with these simple methods.

  10. A prospective study to evaluate the accuracy of pulse power analysis to monitor cardiac output in critically ill patients

    Directory of Open Access Journals (Sweden)

    Grounds R Michael

    2008-02-01

    Full Text Available Abstract Background Intermittent measurement of cardiac output may be performed using a lithium dilution technique (LiDCO. This can then be used to calibrate a pulse power algorithm of the arterial waveform which provides a continuous estimate of this variable. The purpose of this study was to examine the duration of accuracy of the pulse power algorithm in critically ill patients with respect to time when compared to measurements of cardiac output by an independent technique. Methods Pulse power analysis was performed on critically ill patients using a proprietary commercial monitor (PulseCO. All measurements were made using an in-dwelling radial artery line and according to manufacturers instructions. Intermittent measurements of cardiac output were made with LiDCO in order to validate the pulse power measurements. These were made at baseline and then following 1, 2, 4 and 8 hours. The LiDCO measurement was considered the reference for comparison in this study. The two methods of measuring cardiac output were then compared by linear regression and a Bland Altman analysis. An error rate for the limits of agreement (LOA between the two techniques of less than 30% was defined as being acceptable for this study. Results 14 critically ill medical and surgical patients were enrolled over a three month period. At baseline patients showed a wide range of cardiac output (median 7.5 L/min, IQR 5.1 -9.0 L/min. The bias and limits of agreement between the two techniques was deemed acceptable for the first four hours of the study with percentage errors being 29%, 22%, and 285 respectively. The percentage error at eight hours following calibration increased to 36%. The ability of the PulseCo to detect changes in cardiac output was assessed with a similar analysis. The PulseCO tracked the changes in cardiac output with adequate accuracy for the first four hours with percentage errors being 20%, 24% and 25%. However at eight hours the error had increased to

  11. In vivo validation of cardiac output assessment in non-standard 3D echocardiographic images

    Science.gov (United States)

    Nillesen, M. M.; Lopata, R. G. P.; de Boode, W. P.; Gerrits, I. H.; Huisman, H. J.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.

    2009-04-01

    Automatic segmentation of the endocardial surface in three-dimensional (3D) echocardiographic images is an important tool to assess left ventricular (LV) geometry and cardiac output (CO). The presence of speckle noise as well as the nonisotropic characteristics of the myocardium impose strong demands on the segmentation algorithm. In the analysis of normal heart geometries of standardized (apical) views, it is advantageous to incorporate a priori knowledge about the shape and appearance of the heart. In contrast, when analyzing abnormal heart geometries, for example in children with congenital malformations, this a priori knowledge about the shape and anatomy of the LV might induce erroneous segmentation results. This study describes a fully automated segmentation method for the analysis of non-standard echocardiographic images, without making strong assumptions on the shape and appearance of the heart. The method was validated in vivo in a piglet model. Real-time 3D echocardiographic image sequences of five piglets were acquired in radiofrequency (rf) format. These ECG-gated full volume images were acquired intra-operatively in a non-standard view. Cardiac blood flow was measured simultaneously by an ultrasound transit time flow probe positioned around the common pulmonary artery. Three-dimensional adaptive filtering using the characteristics of speckle was performed on the demodulated rf data to reduce the influence of speckle noise and to optimize the distinction between blood and myocardium. A gradient-based 3D deformable simplex mesh was then used to segment the endocardial surface. A gradient and a speed force were included as external forces of the model. To balance data fitting and mesh regularity, one fixed set of weighting parameters of internal, gradient and speed forces was used for all data sets. End-diastolic and end-systolic volumes were computed from the segmented endocardial surface. The cardiac output derived from this automatic segmentation was

  12. In vivo validation of cardiac output assessment in non-standard 3D echocardiographic images

    Energy Technology Data Exchange (ETDEWEB)

    Nillesen, M M; Lopata, R G P; Gerrits, I H; Thijssen, J M; De Korte, C L [Clinical Physics Laboratory-833, Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); De Boode, W P [Neonatology, Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Huisman, H J [Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Kapusta, L [Pediatric Cardiology, Department of Pediatrics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)], E-mail: m.m.nillesen@cukz.umcn.nl

    2009-04-07

    Automatic segmentation of the endocardial surface in three-dimensional (3D) echocardiographic images is an important tool to assess left ventricular (LV) geometry and cardiac output (CO). The presence of speckle noise as well as the nonisotropic characteristics of the myocardium impose strong demands on the segmentation algorithm. In the analysis of normal heart geometries of standardized (apical) views, it is advantageous to incorporate a priori knowledge about the shape and appearance of the heart. In contrast, when analyzing abnormal heart geometries, for example in children with congenital malformations, this a priori knowledge about the shape and anatomy of the LV might induce erroneous segmentation results. This study describes a fully automated segmentation method for the analysis of non-standard echocardiographic images, without making strong assumptions on the shape and appearance of the heart. The method was validated in vivo in a piglet model. Real-time 3D echocardiographic image sequences of five piglets were acquired in radiofrequency (rf) format. These ECG-gated full volume images were acquired intra-operatively in a non-standard view. Cardiac blood flow was measured simultaneously by an ultrasound transit time flow probe positioned around the common pulmonary artery. Three-dimensional adaptive filtering using the characteristics of speckle was performed on the demodulated rf data to reduce the influence of speckle noise and to optimize the distinction between blood and myocardium. A gradient-based 3D deformable simplex mesh was then used to segment the endocardial surface. A gradient and a speed force were included as external forces of the model. To balance data fitting and mesh regularity, one fixed set of weighting parameters of internal, gradient and speed forces was used for all data sets. End-diastolic and end-systolic volumes were computed from the segmented endocardial surface. The cardiac output derived from this automatic segmentation was

  13. Cardiac output response to changes of the atrioventricular delay in different body positions and during exercise in patients receiving cardiac resynchronization therapy

    DEFF Research Database (Denmark)

    Ståhlberg, Marcus; Damgaard, Morten; Norsk, Peter; Gabrielsen, Anders; Sahlén, Anders; Linde, Cecilia; Braunschweig, Frieder

    2009-01-01

    prolonged by 40 ms in 27 CRT patients and 9 controls without heart failure. Cardiac output (CO) was measured by inert gas rebreathing (Innocor) as the average over different body positions (left-lateral, supine, sitting, standing, and exercise). In eight CRT patients with an implantable haemodynamic monitor...

  14. Impact of pacing modality and biventricular pacing on cardiac output and coronary conduit flow in the post-cardiotomy patient.

    LENUS (Irish Health Repository)

    Healy, David G

    2012-02-03

    We have previously demonstrated the role of univentricular pacing modalities in influencing coronary conduit flow in the immediate post-operative period in the cardiac surgery patient. We wanted to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing. Sixteen patients undergoing first time elective coronary artery bypass grafting who required pacing following surgery were recruited. Comparison of cardiac output and coronary conduit flow was performed between VVI and DDD pacing with a single right ventricular lead and biventricular pacing lead placement. Cardiac output was measured using arterial pulse waveform analysis while conduit flow was measured using ultrasonic transit time methodology. Cardiac output was greatest with DDD pacing using right ventricular lead placement only [DDD-univentricular 5.42 l (0.7), DDD-biventricular 5.33 l (0.8), VVI-univentricular 4.71 l (0.8), VVI-biventricular 4.68 l (0.6)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.023) and VVI-biventricular pacing (P=0.001) but there was no significant advantage to DDD-biventricular pacing (P=0.45). In relation to coronary conduit flow, DDD pacing again had the highest flow [DDD-univentricular 55 ml\\/min (24), DDD-biventricular 52 ml\\/min (25), VVI-univentricular 47 ml\\/min (23), VVI-biventricular 50 ml\\/min (26)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.006) pacing but not significantly different to VVI-biventricular pacing (P=0.109) or DDD-biventricular pacing (P=0.171). Pacing with a DDD modality offers the optimal coronary conduit flow by maximising cardiac output. Biventricular lead placement offered no significant benefit to coronary conduit flow or cardiac output.

  15. Measurement of cardiac output during exercise in healthy, trained humans using lithium dilution and pulse contour analysis

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the use of pulse contour analysis calibrated with lithium dilution in a single device (LiDCO™) for measurement of cardiac output (.Q) during exercise in healthy volunteers. We sought to; (a) compare pulse contour analysis (PulseCO) and lithium indicator dilution (LiDCO) for the measurement of .Q during exercise, and (b) assess the requirement for recalibration of PulseCO with LiDCO during exercise. Ten trained males performed multi-stage cycling exercise at intensities below and above ventilatory threshold before constant load maximal exercise to exhaustion. Uncalibrated PulseCO .Q (.Qraw) was compared to that calibrated with lithium dilution at baseline (.Qbaseline), during submaximal exercise below (.Qlow) and above (.Qhigh) ventilatory threshold, and at each exercise stage individually (.Qexercise). There was a significant difference between .Qbaseline and all other calibration methods during exercise, but not at rest. No significant differences were observed between other methods. Closest agreement with .Qexercise was observed for .Qhigh (bias ± limits of agreement: 4.8 ± 30.0%). The difference between .Qexercise and both .Qlow and .Qraw was characterized by low bias (4–7%) and wide limits of agreement (>±40%). Calibration of pulse contour analysis with lithium dilution prior to exercise leads to a systematic overestimation of exercising cardiac output. A single calibration performed during exercise above the ventilatory threshold provided acceptable limits of agreement with an approach incorporating multiple calibrations throughout exercise. Pulse contour analysis may be used for .Q measurement during exercise providing the system is calibrated during exercise. (paper)

  16. Comparison between continuous non-invasive estimated cardiac output by pulse wave transit time and thermodilution method

    Directory of Open Access Journals (Sweden)

    Ashish C Sinha

    2014-01-01

    Full Text Available Aims and Objectives: Cardiac output (CO measurement is essential for many therapeutic decisions in anesthesia and critical care. Most available non-invasive CO measuring methods have an invasive component. We investigate "pulse wave transit time" (estimated continuous cardiac output [esCCO] a method of CO measurement that has no invasive component to its use. Materials and Methods: After institutional ethical committee approval, 14 adult (21-85 years patients undergoing surgery and requiring pulmonary artery catheter (PAC for measuring CO, were included. Postoperatively CO readings were taken simultaneously with thermodilution (TD via PAC and esCCO, whenever a change in CO was expected due to therapeutic interventions. Both monitoring methods were continued until patients′ discharge from the Intensive Care Unit and observer recording values using TD method was blinded to values measured by esCCO system. Results: Three hundred and one readings were obtained simultaneously from both methods. Correlation and concordance between the two methods was derived using Bland-Altman analysis. Measured values showed significant correlation between esCCO and TD ( r = 0.6, P < 0.001, 95% confidence limits of 0.51-0.68. Mean and (standard deviation for bias and precision were 0.13 (2.27 L/min and 6.56 (2.19 L/min, respectively. The 95% confidence interval for bias was - 4.32 to 4.58 L/min and for precision 2.27 to10.85 L/min. Conclusions: Although, esCCO is the only true non-invasive continuous CO monitor available and even though its values change proportionately to TD method (gold standard with the present degree of error its utility for clinical/therapeutic decision-making is questionable.

  17. Estimation of cardiac output by first-pass data with technetium-99m-labeled myocardial perfusion imaging agent

    International Nuclear Information System (INIS)

    Technetium-99m-tetrofosmin, a myocardial perfusion imaging agent was used for estimation of cardiac output by means of first-pass radionuclide angiography performed in the anterior projection. Region of interests (ROIs) were assigned over right ventricle, left ventricle and whole chest, and time activity curves (TACs) were obtained. Cardiac output indices (COIs) were calculated by the following equation; COI=p3/2·Qc/∫0tA(s)ds, where p=number of pixels of the ventricular ROI, Qc=the peak count rate of the TAC obtained from the whole chest's ROI and ∫0tA(s)ds=the area under ventricular TAC. The COI(y) determined by ROI over the left ventricle yield the best correlation with the cardiac output by conventional radionuclide method (x) (y=0.0381x+6.22, r=0.828, n=48, p<0.001). In conclusion, cardiac output can be easily measured with first pass data using myocardial perfusion imaging agent. (author)

  18. Management of perioperative low cardiac output state without extracorporeal life support: What is feasible?

    International Nuclear Information System (INIS)

    A transient and reversible reduction in cardiac output–low cardiac output state (LCOS) often occurs following surgery for congenital heart disease. Inappropriately managed LCOS is a risk factor for increased morbidity and death. LCOS may occasionally be progressive and refractory needing a period of “myocardial rest” with extracorporeal life support (ECLS). ECLS is currently considered a routine tool available for rapid deployment in most industrialized countries. Accumulated experience and refinements in technology have led to improving survivals – discharge survivals of 35%–50%, with almost 100% survival in select groups on elective left ventricular assist device. Thus, there is an increasing trend to initiate ECLS “early or electively in the operating room” in high-risk patients. India has a huge potential need for ECLS given the large number of infants presenting late with preexisting ventricular dysfunction or in circulatory collapse. ECLS is an expensive and resource consuming treatment modality and is not a viable therapeutic option in our country. The purpose of this paper is to reiterate an anticipatory, proactive approach to LCOS: (1) methods for early detection of evolving LCOS and (2) timely initiation of individualized therapy. This paper also explores what is feasible with the refinement of “simple, conventional, inexpensive strategies” for the management of LCOS. Therapy for LCOS should be multimodal based on the type of circulation and physiology. Our approach to LCOS includes: (1) intraoperative strategies, (2) aggressive afterload reduction, (3) lusitropy, (4) exclusion of structural defects, (5) harnessing cardiopulmonary interactions, and (6) addressing metabolic and endocrine abnormalities. We have achieved a discharge survival rate of greater than 97% with these simple methods

  19. Pulmonary diffusing capacity, capillary blood volume, and cardiac output during sustained microgravity

    Science.gov (United States)

    Prisk, G. K.; Guy, Harold J. B.; Elliott, Ann R.; Deutschman, Robert A., III; West, John B.

    1993-01-01

    We measured pulmonary diffusing capacity (DL), diffusing capacity per unit lung volume, pulmonary capillary blood volume (Vc), membrane diffusing capacity (Dm), pulmonary capillary blood flow or cardiac output (Qc), and cardiac stroke volume (SV) in four subjects exposed to nine days of microgravity. DL in microgravity was elevated compared with preflight standing values and was higher than preflight supine because of the elevation of both Vc and Dm. The elevation in Vc was comparable to that measured supine in 1 G, but the increase in Dm was in sharp contrast to the supine value. We postulate that, in 0 G, pulmonary capillary blood is evenly distributed throughout the lung, providing for uniform capillary filling, leading to an increase in the surface area available for diffusion. By contrast, in the supine 1-G state, the capillaries are less evenly filled, and although a similar increase in blood volume is observed, the corresponding increase in surface area does not occur. DL and its subdivisions showed no adaptive changes from the first measurement 24 h after the start of 0 G to eight days later. Similarly, there were no trends in the postflight data, suggesting that the principal mechanism of these changes was gravitational. The increase in Dm suggests that subclinical pulmonary edema did not result from exposure to 0 G. Qc was modestly increased inflight and decreased postflight compared with preflight standing. Compared with preflight standing, SV was increased 46 percent inflight and decreased 14 percent in the 1st week postflight. There were temporal changes in Qc and SV during 0 G, with the highest values recorded at the first measurement, 24 h into the flight. The lowest values of Qc and SV occurred on the day of return.

  20. State-shared model for multiple-input multiple-output systems

    Institute of Scientific and Technical Information of China (English)

    Zhenhua TIAN; Karlene A. HOO

    2005-01-01

    This work proposes a method to construct a state-shared model for multiple-input multiple-output (MIMO)systems. A state-shared model is defined as a linear time invariant state-space structure that is driven by measurement signals-the plant outputs and the manipulated variables, but shared by different multiple input/output models. The genesis of the state-shared model is based on a particular reduced non-minimal realization. Any such realization necessarily fulfills the requirement that the output of the state-shared model is an asymptotically correct estimate of the output of the plant, if the process model is selected appropriately. The approach is demonstrated on a nonlinear MIMO system- a physiological model of calcium fluxes that controls muscle contraction and relaxation in human cardiac myocytes.

  1. A novel continuous cardiac output monitor based on pulse wave transit time.

    Science.gov (United States)

    Sugo, Yoshihiro; Ukawa, Teiji; Takeda, Sunao; Ishihara, Hironori; Kazama, Tomiei; Takeda, Junzo

    2010-01-01

    Monitoring cardiac output (CO) is important for the management of patient circulation in an operation room (OR) or intensive care unit (ICU). We assumed that the change in pulse wave transit time (PWTT) obtained from an electrocardiogram (ECG) and a pulse oximeter wave is correlated with the change in stroke volume (SV), from which CO is derived. The present study reports the verification of this hypothesis using a hemodynamic analysis theory and animal study. PWTT consists of a pre-ejection period (PEP), the pulse transit time through an elasticity artery (T(1)), and the pulse transit time through peripheral resistance arteries (T(2)). We assumed a consistent negative correlation between PWTT and SV under all conditions of varying circulatory dynamics. The equation for calculating SV from PWTT was derived based on the following procedures. 1. Approximating SV using a linear equation of PWTT. 2. The slope and y-intercept of the above equation were determined under consideration of vessel compliance (SV was divided by Pulse Pressure (PP)), animal type, and the inherent relationship between PP and PWTT. Animal study was performed to verify the above-mentioned assumption. The correlation coefficient of PWTT and SV became r = -0.710 (p 〈 0.001), and a good correlation was admitted. It has been confirmed that accurate continuous CO and SV measurement is only possible by monitoring regular clinical parameters (ECG, SpO2, and NIBP). PMID:21095971

  2. High Output Cardiac Failure Resolving after Repair of AV Fistula in a Six-Month-Old.

    Science.gov (United States)

    Teomete, Uygar; Gugol, Rubee Anne; Neville, Holly; Dandin, Ozgur; Young, Ming-Lon

    2016-01-01

    Background. Acquired AVF in pediatrics are commonly caused by iatrogenic means, including arterial or venous punctures. These fistulae can cause great hemodynamic stress on the heart as soon as they are created. Case. A six-month-old 25-week gestation infant was referred for respiratory distress. Initial exam revealed tachypnea, tachycardia, and hypertension. There was a bruit noted on her left arm. An ultrasound showed an arteriovenous fistula. Its location, however, precluded intervention because of the high risk for limb-loss. An echocardiogram showed evidence of pulmonary hypertension that was treated with sildenafil and furosemide. However, no improvement was seen. On temporary manual occlusion of the fistula, the patient was noted to have increased her blood pressure and decreased her heart rate, suggesting significant hemodynamic effect of the fistula. The fistula was subsequently ligated and the patient clinically and echocardiographically improved. Conclusion. A patient in high output cardiac failure or pulmonary artery hypertension, especially prematüre patients with preexisting lung disease, should be probed for history of multiple punctures, trauma, or surgery and should have prompt evaluation for AVF. If it can be diagnosed and repaired, most of the cases have been shown to decrease the stress on the heart and reverse the pathologic hemodynamics. PMID:26885434

  3. Thermal dilution measurement of cardiac output in dogs using an analog computer.

    Science.gov (United States)

    Hendriks, F F; Schipperheyn, J J; Quanjer, P H

    1978-01-01

    Thermal dilution cardiac output determinations in dogs were compared to simultaneously performed Fick oxygen measurements. The purpose of this study was to validate in dog experiments a method for thermal dilution measurement which employs a double-thermistor catheter combined with an automatic computer as described by Olsson et al. Dilution and injectate temperature are entered directly into the calculation. The method does not employ logarithmic extrapolation, integration of the dilution signal being terminated when a preset cut-off level is reached. Errors due to recirculation, thermal capacitance of the right heart and heat exchange with the catheter's dead space require the use of an empirically derived correction factor, which in dogs was found to be significantly different from the factor used for human thermal dilution curves. With the appropriate cut-off level and correction factor a good agreement was found between the results of the thermal dilution and the Fick method. The regression equation for 47 experiments was found to be COtd = 0.95 COFick + 0.08; the correlation coefficient was 0.94. PMID:728031

  4. Cardiac Output Measurements in Septic Patients: Comparing the Accuracy of USCOM to PiCCO

    Directory of Open Access Journals (Sweden)

    Sophia Horster

    2012-01-01

    Full Text Available USCOM is an ultrasound-based method which has been accepted for noninvasive hemodynamic monitoring in various clinical conditions (USCOM, Ultrasonic cardiac output monitoring. The present study aimed at comparing the accuracy of the USCOM device with that of the thermodilution technique in patients with septicemia. We conducted a prospective observational study in a medical but noncardiological ICU of a university hospital. Septic adult patients (median age 55 years, median SAPS-II-Score 43 points on mechanical ventilation and catecholamine support were monitored with USCOM and PiCCO (=70. Seventy paired left-sided CO measurements (transaortic access = COUS-A were obtained. The mean COUS-A were 6.55 l/min (±2.19 versus COPiCCO 6.5 l/min (±2.18. The correlation coefficient was =0.89. Comparison by Bland-Altman analysis revealed a bias of −0.36 l/min (±0.99 l/min leading to a mean percentage error of 29%. USCOM is a feasible and rapid method to evaluate CO in septic patients. USCOM does reliably represent CO values as compared to the reference technique based on thermodilution (PiCCO. It seems to be appropriate in situations where CO measurements are most pertinent to patient management.

  5. Non-invasive measurement of cardiac output by Finometer in patients with cirrhosis

    DEFF Research Database (Denmark)

    Kaltoft, Nicolai Stefan; Hobolth, L; Møller, S

    2010-01-01

    The Finometer measures haemodynamic parameters including cardiac output (CO) using non-invasive volume-clamp techniques. The aim of this study was to determine the accuracy of the Finometer in hyperdynamic cirrhotic patients using an invasive indicator dilution technique as control. CO was measured......(I) was 6.1 +/- 1.6 [3.9;9.7] l min(-1) (mean +/- SD [range]) compared to mean CO(F) of 7.2 +/- 2.3 [3.1;11.9] l min(-1). There was a mean difference between CO(F) and CO(I) of 1.0 +/- 1.8 [-2.1;4.0] l min(-1) and 95% confidence interval of [0.2;1.8], P<0.001. In patients with measurements before and...... after beta-blockade, mean DeltaCO(I) was 1.6 +/- 1.4 [-0.1;3.3] l min(-1) compared to mean DeltaCO(F) of 1.9 +/- 1.3 [0.4;3.8] l min(-1). Mean difference between DeltaCO(F) and DeltaCO(I) was 0.3 +/- 0.3 [-0.2;0.7] l min(-1) with a 95% confidence interval of [-0.1;0.6], P = 0.11. Compared with invasive...

  6. Improved system measures output energy of pyrotechnic devices

    Science.gov (United States)

    Shortly, E. M.

    1966-01-01

    System for measuring the output energy of pyrotechnic devices discharges the reaction products into a test chamber. It measures the radiant heat output from a pinhole aperture as well as internal pressure changes on a common time base.

  7. STABILITY ANALYSIS OF THE DYNAMIC INPUT-OUTPUT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    GuoChonghui; TangHuanwen

    2002-01-01

    The dynamic input-output model is well known in economic theory and practice. In this paper, the asymptotic stability and balanced growth solutions of the dynamic input-output system are considered. Under some natural assumptions which do not require the technical coefficient matrix to be indecomposable,it has been proved that the dynamic input-output system is not asymptotically stable and the closed dynamic input-output model has a balanced growth solution.

  8. Cooperative linear output regulation for networked systems by dynamic measurement output feedback

    Science.gov (United States)

    Li, Shaobao; Feng, Gang; Wang, Juan; Luo, Xiaoyuan; Guan, Xinping

    2016-04-01

    This paper investigates the cooperative linear output regulation problem of a class of heterogeneous networked systems with a common reference input but with different disturbances for individual nodes. A novel distributed control law is presented based on dynamic measurement output feedback. It is shown that the overall networked closed-loop control system is asymptotically stable and the output regulation errors asymptotically approach zero as time goes to infinity under a sufficient and necessary condition. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed control law.

  9. Measurement of cardiac output during exercise by open-circuit acetylene uptake.

    Science.gov (United States)

    Barker, R C; Hopkins, S R; Kellogg, N; Olfert, I M; Brutsaert, T D; Gavin, T P; Entin, P L; Rice, A J; Wagner, P D

    1999-10-01

    Noninvasive measurement of cardiac output (QT) is problematic during heavy exercise. We report a new approach that avoids unpleasant rebreathing and resultant changes in alveolar PO(2) or PCO(2) by measuring short-term acetylene (C(2)H(2)) uptake by an open-circuit technique, with application of mass balance for the calculation of QT. The method assumes that alveolar and arterial C(2)H(2) pressures are the same, and we account for C(2)H(2) recirculation by extrapolating end-tidal C(2)H(2) back to breath 1 of the maneuver. We correct for incomplete gas mixing by using He in the inspired mixture. The maneuver involves switching the subject to air containing trace amounts of C(2)H(2) and He; ventilation and pressures of He, C(2)H(2), and CO(2) are measured continuously (the latter by mass spectrometer) for 20-25 breaths. Data from three subjects for whom multiple Fick O(2) measurements of QT were available showed that measurement of QT by the Fick method and by the C(2)H(2) technique was statistically similar from rest to 90% of maximal O(2) consumption (VO(2 max)). Data from 12 active women and 12 elite male athletes at rest and 90% of VO(2 max) fell on a single linear relationship, with O(2) consumption (VO(2)) predicting QT values of 9.13, 15.9, 22.6, and 29.4 l/min at VO(2) of 1, 2, 3, and 4 l/min. Mixed venous PO(2) predicted from C(2)H(2)-determined QT, measured VO(2), and arterial O(2) concentration was approximately 20-25 Torr at 90% of VO(2 max) during air breathing and 10-15 Torr during 13% O(2) breathing. This modification of previous gas uptake methods, to avoid rebreathing, produces reasonable data from rest to heavy exercise in normal subjects. PMID:10517785

  10. Predictors of Post Pericardiotomy Low Cardiac Output Syndrome in Patients With Pericardial Effusion

    Directory of Open Access Journals (Sweden)

    Sabzi Feridoun

    2015-03-01

    Full Text Available Introduction: Pathological involvement of pericardium by any disease that resulting in effusion may require decompression and pericardiectomy. The current article describes rare patients with effusion who after pericadiectomy and transient hemodynamic improvement rapidly developed progressive heart failure and subsequent multi organ failure.Methods: During periods of five years, 423 patients in our hospital underwent pericardiotomy for decompression of effusion. The clinical characteristics of those patient with postoperative low cardiac output (B group (14 cases recorded and compared with other patients without this postoperative complication (A group by test and X2. Significant variables in invariables (P≤0.1 entered in logistic regression analysis and odd ratio of these significant variables obtained. Results: Idiopathic pericardial effusion, malignancy, renal failure, connective tissue disease, viral pericarditis was found in 125 patients (27%, 105 patients (25.4%, 65 patients (15.6%, 50 (17.1% and 10 (2.4% of patients subsequently. The factors that predict post-operative death in logistic regression analysis were malignancy, radiotherapy, constrictive pericarditis inotropic drug using IABP using, pre-operative EF and pericardial calcification.Conclusion: Certain preoperative variables such as malignancy, radiotherapy, low EF, calcified pericardium and connective tissue disease are associated with POLCOS and post-operative risk of death. This paradoxical response to pericardial decompression may be more frequent than currently appreciated. Its cause may relate to the sudden removal of the chronic external ventricular support from the effusion or thicken pericardium resulting in ventricular dilatation and failure or intra operative myocardial injury due to pericardiectomy of calcified pericardium, radiation and cardiomyopathy.

  11. The effect of halothane on the distribution of cardiac output and organ blood flows in the hemorrhagic, hypotensive dog

    International Nuclear Information System (INIS)

    Halothane was given to dogs which had been bled to an arterial mean blood pressure of 60 mmHg, and the circulatory effects were studied with the aid of the radioactive microsphere technique. The cardiac output and coronary blood flow were well maintained, whereas the arterial mean blood pressure was slightly, and the stroke volume markedly increased, indicating an improved heart function. The blood flows to the brain, lungs, liver and kidneys were well preserved throughout the anesthesia. The effect of retransfusing the withdrawn blood was also studied, and it resulted in an increased cardiac output, arterial mean blood pressure and increased blood flows to the heart, lungs, spleen, bowel and liver. (author)

  12. Input–output robustness in simple bacterial signaling systems

    OpenAIRE

    Shinar, Guy; Milo, Ron; Martínez, María Rodríguez; Alon, Uri

    2007-01-01

    Biological signaling systems produce an output, such as the level of a phosphorylated protein, in response to defined input signals. The output level as a function of the input level is called the system's input–output relation. One may ask whether this input–output relation is sensitive to changes in the concentrations of the system's components, such as proteins and ATP. Because component concentrations often vary from cell to cell, it might be expected that the input–output relation will l...

  13. The use of a cardiac output monitor to guide the initial fluid resuscitation in a patient with burns

    OpenAIRE

    Reid, Robert Darren; Jayamaha, John

    2007-01-01

    A case of initial resuscitation of a patient with severe burns is described. Such patients can have hypotension and reduced organ perfusion for a number of reasons, and can remain in the emergency department for many hours while awaiting transfer to specialist centres. The case provides a comparison between resuscitation using traditional burns formulae and a relatively new and simple‐to‐use cardiac output (CO) monitor—the Vigileo monitor (Edwards Lifesciences, Irvine, California, USA). The c...

  14. HEART FAILURE WITH LOW CARDIAC OUTPUT AND RISK OF DEVELOPMENT OF LESIONS IN THE CEREBRAL WHITE MATTER

    OpenAIRE

    2005-01-01

    Aim: Diminished cardiac output can lead to the development of white matter lesions. White matter lesions are related to cognitive impairment, stroke risk and vascular death, yet the precise aetiology is uncertain. Methods: In this study we recruited 130 patients attending our medicine and neurology outpatient department, and divided them into those with a history of heart failure (n:24), atrial fibrillation (n:26), and those with atherosclerotic risk factors (n:80). The patients without low o...

  15. Multiple input/output random vibration control system

    Science.gov (United States)

    Unruh, James F.

    1988-01-01

    A multi-input/output random vibration control algorithm was developed based on system identification concepts derived from random vibration spectral analysis theory. The unique features of the algorithm are: (1) the number of input excitors and the number of output control responses need not be identical; (2) the system inverse response matrix is obtained directly from the input/output spectral matrix; and (3) the system inverse response matrix is updated every control loop cycle to accommodate system amplitude nonlinearities. A laboratory demonstration case of two imputs with three outputs is presented to demonstrate the system capabilities.

  16. Non-Invasive Determination of Cardiac Output in Pre-Capillary Pulmonary Hypertension.

    Directory of Open Access Journals (Sweden)

    Frédéric Lador

    Full Text Available Cardiac output (CO is a major diagnostic and prognostic factor in pre-capillary pulmonary hypertension (PH. Reference methods for CO determination, like thermodilution (TD, require invasive procedures and allow only steady-state measurements. The Modelflow (MF method is an appealing technique for this purpose as it allows non-invasive and beat-by-beat determination of CO.We aimed to compare CO values obtained simultaneously from non-invasive pulse wave analysis by MF (COMF and by TD (COTD to determine its precision and accuracy in pre-capillary PH. The study was performed on 50 patients with pulmonary arterial hypertension (PAH or chronic thrombo-embolic PH (CTEPH. CO was determined at rest in all patients (n = 50 and during nitric oxide vasoreactivity test, fluid challenge or exercise (n = 48.Baseline COMF and COTD were 6.18 ± 1.95 and 5.46 ± 1.95 L·min-1, respectively. Accuracy and precision were 0.72 and 1.04 L·min-1, respectively. Limits of agreement (LoA ranged from -1.32 to 2.76 L·min-1. Percentage error (PE was ±35.7%. Overall sensitivity and specificity of COMF for directional change were 95.2% and 82.4%, (n = 48 and 93.3% and 100% for directional changes during exercise (n = 16, respectively. After application of a correction factor (1.17 ± 0.25, neither proportional nor fixed bias was found for subsequent CO determination (n = 48. Accuracy was -0.03 L·min-1 and precision 0.61 L·min-1. LoA ranged from -1.23 to 1.17 L·min-1 and PE was ±19.8%.After correction against a reference method, MF is precise and accurate enough to determine absolute values and beat-by-beat relative changes of CO in pre-capillary PH.

  17. Femoral Blood Flow and Cardiac Output During Blood Flow Restricted Leg Press Exercise

    Science.gov (United States)

    Everett, M. E.; Hackney, K.; Ploutz-Snyder, L.

    2011-01-01

    Low load blood flow restricted resistance exercise (LBFR) causes muscle hypertrophy that may be stimulated by the local ischemic environment created by the cuff pressure. However, local blood flow (BF) during such exercise is not well understood. PURPOSE: To characterize femoral artery BF and cardiac output (CO) during leg press exercise (LP) performed at a high load (HL) and low load (LL) with different levels of cuff pressure. METHODS: Eleven subjects (men/women 4/7, age 31.4+/-12.8 y, weight 68.9+/-13.2 kg, mean+/-SD) performed 3 sets of supine left LP to fatigue with 90 s of rest in 4 conditions: HL (%1-RM/cuff pressure: 80%/0); LL (20%/0); LBFR(sub DBP) (20%/1.3 x diastolic blood pressure, BP); LBFR(sub SBP) (20%/1.3 x supine systolic BP). The cuff remained inflated throughout the LBFR exercise sessions. Artery diameter, velocity time integral (VTI), and stroke volume (SV) were measured using Doppler ultrasound at rest and immediately after each set of exercise. Heart rate (HR) was monitored using a 3-lead ECG. BF was calculated as VTI x vessel cross-sectional area. CO was calculated as HR x SV. The data obtained after each set of exercise were averaged and used for analyses. Multi-level modeling was used to determine the effect of exercise condition on dependent variables. Statistical significance was set a priori at p LL (9.92+/-0.82 cm3) > LBFR(sub dBP)(6.47+/-0.79 cm3) > LBFR(sub SBP) (3.51+/-0.59 cm3). Blunted exercise induced increases occurred in HR, SV, and CO after LBFR compared to HL and LL. HR increased 45% after HL and LL and 28% after LBFR (p<0.05), but SV increased (p<0.05) only after HL. Consequently, the increase (p<0.05) in CO was greater in HL and LL (approximately 3 L/min) than in LBFR (approximately 1 L/min). CONCLUSION: BF during LBFR(sub SBP) was 1/3 of that observed in LL, which supports the hypothesis that local ischemia stimulates the LBFR hypertrophic response. As the cuff did not compress the artery, the ischemia may have occurred

  18. The output feedback control for uncertain nonholonomic systems

    Institute of Scientific and Technical Information of China (English)

    Qiangde WANG; Chunling WEI; Siying ZHANG

    2006-01-01

    This paper considers the problems of almost asymptotic stabilization and global asymptotic regulation (GAR) by output feedback for a class of uncertain nonholonomic systems. By combining the nonsmooth change of coordinates and output feedback domination design together, we construct a simple linear time-varying output feedback controller, which can universally stabilize a whole family of uncertain nonholonomic systems. The simulation demonstrates the effectiveness of the proposed controller.

  19. Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement

    International Nuclear Information System (INIS)

    The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

  20. Cooperative Output Regulation of Singular Heterogeneous Multiagent Systems.

    Science.gov (United States)

    Ma, Qian; Xu, Shengyuan; Lewis, Frank L; Zhang, Baoyong; Zou, Yun

    2016-06-01

    This paper investigates the cooperative output regulation problem of singular heterogeneous multiagent systems. General distributed observers are proposed for every agent obtaining the estimated state of the exosystem. The feedforward control technique and reduced-order approach are used to design distributed singular output feedback controllers and distributed normal output feedback controllers. The proposed cooperative dynamic controller is dependent on the plant parameters and the interaction topologies. A simulation example is provided to demonstrate the effectiveness of the proposed design method. PMID:26173224

  1. The Cardiac Conduction System: Generation and Conduction of the Cardiac Impulse.

    Science.gov (United States)

    Kennedy, Alan; Finlay, Dewar D; Guldenring, Daniel; Bond, Raymond; Moran, Kieran; McLaughlin, James

    2016-09-01

    In this article, the authors outline the key components behind the automated generation of the cardiac impulses and the effect these impulses have on cardiac myocytes. Also, a description of the key components of the normal cardiac conduction system is provided, including the sinoatrial node, the atrioventricular node, the His bundle, the bundle branches, and the Purkinje network. Finally, an outline of how each stage of the cardiac conduction system is represented on the electrocardiogram is described, allowing the reader of the electrocardiogram to translate background information about the normal cardiac conduction system to everyday clinical practice. PMID:27484656

  2. Exercise-related change in airway blood flow in humans: Relationship to changes in cardiac output and ventilation

    OpenAIRE

    Morris, Norman R; Ceridon, Maile L.; Beck, Kenneth C.; Strom, Nicholas A.; Schneider, Donald A; Mendes, Eliana S; Wanner, Adam; Johnson, Bruce D.

    2008-01-01

    This study examined the relationship between airway blood flow (Q̇aw), ventilation (V̇E) and cardiac output (Q̇tot) during exercise in healthy humans (n = 12, mean age 34 ± 11 yr). Q̇aw was estimated from the uptake of the soluble gas dimethyl ether while V̇E and Q̇tot were measured using open circuit spirometry. Measurements were made prior to and during exercise at 34 ± 5W (Load 1) and 68 ± 10 W (Load 2) and following the cessation of exercise (recovery). Q̇aw increased in a stepwise fashio...

  3. Noninvasive cardiac output determination using applanation tonometry-derived radial artery pulse contour analysis in critically ill patients

    DEFF Research Database (Denmark)

    Compton, Friederike; Wittrock, Marc; Schaefer, Juergen-Heiner;

    2008-01-01

    Conventional thermodilution cardiac output (CO) monitoring is limited mainly to intensive care units and operating rooms because it requires the use of invasive techniques. To reduce the potential for complications and to broaden the applicability of hemodynamic monitoring, noninvasive methods for...... were analyzed with bias and precision statistics, a large bias of 2.03 L x min(-1) x m(-2) and a high percentage error of 85% were found between the invasive measurements and applanation tonometry-derived CO estimates, with the noninvasive CO results being significantly lower than the invasive ones (P...

  4. Specification of the Cardiac Conduction System by Transcription Factors

    OpenAIRE

    Hatcher, Cathy J.; Basson, Craig T.

    2009-01-01

    Diseases of the cardiovascular system that cause sudden cardiac deaths are often caused by lethal arrhythmias that originate from defects in the cardiac conduction system. Development of the cardiac conduction system is a complex biological process that can be wrought with problems. Although several genes involved in mature conduction system function have been identified, their association with development of specific subcomponents of the cardiac conduction system remains challenging. Several...

  5. Optically coupled CAMAC analog input output system

    International Nuclear Information System (INIS)

    In an accelerator system, especially in ion sources, signals are exchanged between devices at different potentials. We have four ion sources in the negative ion injector for the JAERI tandem accelerator. Voltage to frequency conversion technic and optical fiber were used in the previous system. When we intended to extend the injector, we decided to revise the system to improve accuracy and reliability. For the purpose, we developed a new CAMAC module. It is an interface device between CAMAC dataway and optical fiber. The module has frequency synthesizers, frequency counters, optical transmitters and optical receivers in it. Accuracy, reliability and maintenability of the system were greatly improved by the module. (author)

  6. Advanced information processing system: Input/output system services

    Science.gov (United States)

    Masotto, Tom; Alger, Linda

    1989-01-01

    The functional requirements and detailed specifications for the Input/Output (I/O) Systems Services of the Advanced Information Processing System (AIPS) are discussed. The introductory section is provided to outline the overall architecture and functional requirements of the AIPS system. Section 1.1 gives a brief overview of the AIPS architecture as well as a detailed description of the AIPS fault tolerant network architecture, while section 1.2 provides an introduction to the AIPS systems software. Sections 2 and 3 describe the functional requirements and design and detailed specifications of the I/O User Interface and Communications Management modules of the I/O System Services, respectively. Section 4 illustrates the use of the I/O System Services, while Section 5 concludes with a summary of results and suggestions for future work in this area.

  7. Input-output equations and observability for polynomial delay systems

    OpenAIRE

    Forsman, K; Habets, LCGJM Luc

    1994-01-01

    This paper discusses and strengthens a result by Fliess (1988) about input-output equations for polynomial systems with time delays. The proof given is more detailed and it opens the way for constructive methods for determining the input-output behavior. A method based on Grobner's approach is described in detail. Furthermore, some connections with observability are exploited.

  8. Optimal Quality Assurance Systems for Agricultural Outputs

    OpenAIRE

    Miguel Carriquiry; Babcock, Bruce A.; Roxana Carbone

    2003-01-01

    New quality assurance systems (QASs) are being put in place to facilitate the flow of information about agricultural and food products. But what constitutes a proper mix of public and private efforts in setting up QASs is an unsettled question. A better understanding of private sector incentives for setting up such systems will help clarify what role the public sector might have in establishing standards. We contribute to this understanding by modeling the optimal degree of "stringency" or as...

  9. Input-output stability for accelerometer control systems

    Science.gov (United States)

    Banks, H. T.; Morris, K. A.

    1991-01-01

    It is shown that, although accelerometer control systems are not well-posed in the sense of Salamon, a well-defined input-output relation exists. It is established that the output of an accelerometer control system can be described by the convolution of the input and a distribution. This distribution is Laplace transformable, and the Laplace transform of the distribution is the transfer function of the system.

  10. Sarcomere length dependence of power output is increased after PKA treatment in rat cardiac myocytes

    OpenAIRE

    Hanft, Laurin M.; McDonald, Kerry S.

    2009-01-01

    The Frank-Starling relationship of the heart yields increased stroke volume with greater end-diastolic volume, and this relationship is steeper after β-adrenergic stimulation. The underlying basis for the Frank-Starling mechanism involves length-dependent changes in both Ca2+ sensitivity of myofibrillar force and power output. In this study, we tested the hypothesis that PKA-induced phosphorylation of myofibrillar proteins would increase the length dependence of myofibrillar power output, whi...

  11. Reduced peripheral arterial blood flow with preserved cardiac output during submaximal bicycle exercise in elderly heart failure

    Directory of Open Access Journals (Sweden)

    Leng Xiaoyan

    2009-11-01

    Full Text Available Abstract Background Older heart failure (HF patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. Methods and Results Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF (aged 68 ± 10 years without large (aorta or medium sized (iliac or femoral artery vessel atherosclerosis, and 13 age and gender matched healthy volunteers underwent a sophisticated battery of assessments including a peak exercise oxygen consumption (peak VO2, b physical function, c cardiovascular magnetic resonance (CMR submaximal exercise measures of aortic and femoral arterial blood flow, and d determination of thigh muscle area. Peak VO2 was reduced in HF subjects (14 ± 3 ml/kg/min compared to healthy elderly subjects (20 ± 6 ml/kg/min (p = 0.01. Four-meter walk speed was 1.35 ± 0.24 m/sec in healthy elderly verses 0.98 ± 0.15 m/sec in HF subjects (p p ≤ 0.03. Conclusion During CMR submaximal bike exercise in the elderly with heart failure, mechanisms other than low cardiac output are responsible for reduced lower extremity blood flow.

  12. Dictionary Writing System: Output and Editorial Modules

    Czech Academy of Sciences Publication Activity Database

    Barbierik, Kamil; Děngeová, Zuzana; Jarý, Vladimír; Liška, Tomáš; Lišková, Michaela; Virius, Miroslav

    Ostrava: VŠB - Technical University of Ostrava, 2014 - (Ministr, J.; Tvrdíková, M.), s. 17-23 ISBN 978-80-248-3555-6. [International Conference on Information Technology for Practice /17./. Ostrava (CZ), 09.10.2014-10.10.2014] R&D Projects: GA MK DF13P01OVV011 Keywords : dictionary writing system * editorial tool * web application Subject RIV: AI - Linguistics

  13. Development of a Selectable Output Ultraviolet Laser System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Here, we propose to develop a breadboard laser system that is capable of producing radiation in two UV wavelengths.  This Selectable Output Ultraviolet Laser...

  14. Robust Input-Output Energy Decoupling for Uncertain Singular Systems

    Institute of Scientific and Technical Information of China (English)

    Xin-Zhuang Dong; Qing-Ling Zhang

    2005-01-01

    This paper addresses the robust input-output energy decoupling problem for uncertain singular systems in which all parameter matrices except E exist as time-varying uncertainties. By means of linear matrix inequalities (LMIs),sufficient conditions are derived for the existence of linear state feedback and input transformation control laws, such that the resulting closed-loop uncertain singular system is generalized quadratically stable and the energy of every input controls mainly the energy of a corresponding output, and influences the energy of other outputs as weakly as possible.

  15. Design of output feedback controller for a unified chaotic system

    Institute of Scientific and Technical Information of China (English)

    Li Wen-Lin; Chen Xiu-Qin; Shen Zhi-Ping

    2008-01-01

    In this paper,the synchronization of a unified chaotic system is investigated by the use of output feedback controllers;a two-input single-output feedback controller and single-input single-output feedback controller are presented to synchronize the unified chaotic system when the states are not all measurable.Compared with the existing results,the controllers designed in this paper have some advantages such as small feedback gain,simple structure and less conservation.Finally,numerical simulations results are provided to demonstrate the validity and effectiveness of the proposed method.

  16. Influence of water immersion, water gymnastics and swimming on cardiac output in patients with heart failure

    Science.gov (United States)

    Schmid, Jean‐Paul; Noveanu, Markus; Morger, Cyrill; Gaillet, Raymond; Capoferri, Mauro; Anderegg, Matthias; Saner, Hugo

    2007-01-01

    Background Whole‐body water immersion leads to a significant shift of blood from the periphery to the intrathoracic circulation, followed by an increase in central venous pressure and heart volume. In patients with severely reduced left ventricular function, this hydrostatically induced volume shift might overstrain the cardiovascular adaptive mechanisms and lead to cardiac decompensation. Aim To assess the haemodynamic response to water immersion, gymnastics and swimming in patients with chronic heart failure (CHF). Methods 10 patients with compensated CHF (62.9 (6.3) years, ejection fraction 31.5% (4.1%), peak oxygen consumption (V̇o2) 19.4 (2.8) ml/kg/min), 10 patients with coronary artery disease (CAD) but preserved left ventricular function (57.2 (5.6) years, ejection fraction 63.9% (5.5%), peak V̇o2 28 (6.3) ml/kg/min), and 10 healthy controls (32.8 (7.2) years, peak V̇o2 45.6 (6) ml/kg/min) were examined. Haemodynamic response to thermoneutral (32°C) water immersion and exercise was measured using a non‐invasive foreign gas rebreathing method during stepwise water immersion, water gymnastics and swimming. Results Water immersion up to the chest increased cardiac index by 19% in controls, by 21% in patients with CAD and by 16% in patients with CHF. Although some patients with CHF showed a decrease of stroke volume during immersion, all subjects were able to increase cardiac index (by 87% in healthy subjects, by 77% in patients with CAD and by 53% in patients with CHF). V̇o2 during swimming was 9.7 (3.3) ml/kg/min in patients with CHF, 12.4 (3.5) ml/kg/min in patients with CAD and 13.9 (4) ml/kg/min in controls. Conclusions Patients with severely reduced left ventricular function but stable clinical conditions and a minimal peak V̇o2 of at least 15 ml/kg/min during a symptom‐limited exercise stress test tolerate water immersion and swimming in thermoneutral water well. Although cardiac index and V̇o2 are lower than in patients

  17. Output Feedback Control for a Class of Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    Keylan Alimhan; Hiroshi Inaba

    2006-01-01

    This paper studies the global stabilization problem by an output controller for a family of uncertain nonlinear systems satisfying some relaxed triangular-type conditions and with dynamics which may not be exactly known. Using a feedback domination design method, we explicitly construct a dynamic output compensator which globally stabilizes such an uncertain nonlinear system. The usefulness of our result is illustrated with an example.

  18. OUTPUT FEEDBACK CONTROL FOR MIMO NONLINEAR SYSTEMS WITH EXOGENOUS SIGNALS

    Institute of Scientific and Technical Information of China (English)

    Ying ZHOU; Yuqiang WU

    2006-01-01

    The paper addresses the global output tracking of a class of multi-input multi-output(MIMO) nonlinear systems affected by disturbances, which are generated by a known exosystem. An adaptive controller is designed based on the proposed observer and the backstepping approach to asymptotically track arbitrary reference signal and to guarantee the boundedness of all the signals in the closed loop system. Finally, the numerical simulation results illustrate the effectiveness of the proposed scheme.

  19. Adaptive Output Regulation of Unknown Linear Systems with Unknown Exosystems

    OpenAIRE

    Mizumoto, Ikuro; Iwai, Zenta

    2009-01-01

    In this paper, the adaptive regulation problem for unknown controlled systems with unknown exosystems was considered. An adaptive output feedback controller with an adaptive internal model was proposed for single input/single output linear minimum phase systems. In the proposed method, a controller with an adaptive internal model was designed through an expanded backstepping strategy of only one step with a parallel feedforward compensator (PFC).

  20. Linearisation via input-output injection of time delay systems

    Science.gov (United States)

    García-Ramírez, Eduardo; Moog, Claude H.; Califano, Claudia; Alejandro Márquez-Martínez, Luis

    2016-06-01

    This paper deals with the problem of linearisation of systems with constant commensurable delays by input-output injection using algebraic control tools based on the theory of non-commutative rings. Solutions for the problem of linearisation free of delays, and with delays of an observable nonlinear time-delay systems are presented based on the analysis of the input-output equation. These results are achieved by means of constructive algorithms that use the nth derivative of the output expressed in terms of the state-space variables instead of the explicit computation of the input-output representation of the system. Necessary and sufficient conditions are established in both cases by means of an invertible change of coordinates.

  1. Classification of hospitals based on measured output: the VA system.

    Science.gov (United States)

    Thomas, J W; Berki, S E; Wyszewianski, L; Ashcraft, M L

    1983-07-01

    Evaluation of hospital performance and improvement of resource allocation in hospital systems require a method for classifying hospitals on the basis of their output. Previous approaches to hospital classification relied largely on input characteristics. The authors propose and apply a procedure for classifying hospitals into groups where within-group hospitals are similar with respect to output. Direct measures of case-mix-adjusted discharges and outpatient visits are the principal measures of patient care output; other measures capture training and research functions. The component measures were weighted, and a composite output measure was calculated for each of the 162 hospitals in the Veterans Administration health care system. The output score then was used as the dependent variable in an Automatic Interaction Detector analysis, which partitioned the 162 hospitals into 10 groups, accounting for 85 per cent of the variance in the dependent variable. An extension of the output classification method is presented for illustration of how the difference between hospitals' actual operating costs and costs predicted on the basis of output can be used in defining isoefficiency groups. PMID:6350744

  2. Cardiac effects of 3-iodothyronamine: a new aminergic system modulating cardiac function.

    Science.gov (United States)

    Chiellini, Grazia; Frascarelli, Sabina; Ghelardoni, Sandra; Carnicelli, Vittoria; Tobias, Sandra C; DeBarber, Andrea; Brogioni, Simona; Ronca-Testoni, Simonetta; Cerbai, Elisabetta; Grandy, David K; Scanlan, Thomas S; Zucchi, Riccardo

    2007-05-01

    3-Iodothyronamine T1AM is a novel endogenous thyroid hormone derivative that activates the G protein-coupled receptor known as trace anime-associated receptor 1 (TAAR1). In the isolated working rat heart and in rat cardiomyocytes, T1AM produced a reversible, dose-dependent negative inotropic effect (e.g., 27+/-5, 51+/-3, and 65+/-2% decrease in cardiac output at 19, 25, and 38 microM concentration, respectively). An independent negative chronotropic effect was also observed. The hemodynamic effects of T1AM were remarkably increased in the presence of the tyrosine kinase inhibitor genistein, whereas they were attenuated in the presence of the tyrosine phosphatase inhibitor vanadate. No effect was produced by inhibitors of protein kinase A, protein kinase C, calcium-calmodulin kinase II, phosphatidylinositol-3-kinase, or MAP kinases. Tissue cAMP levels were unchanged. In rat ventricular tissue, Western blot experiments with antiphosphotyrosine antibodies showed reduced phosphorylation of microsomal and cytosolic proteins after perfusion with synthetic T1AM; reverse transcriptase-polymerase chain reaction experiments revealed the presence of transcripts for at least 5 TAAR subtypes; specific and saturable binding of [125I]T1AM was observed, with a dissociation constant in the low micromolar range (5 microM); and endogenous T1AM was detectable by tandem mass spectrometry. In conclusion, our findings provide evidence for the existence of a novel aminergic system modulating cardiac function. PMID:17284482

  3. Reliability systems for implantable cardiac defibrillator batteries

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, E.S. [Wilson Greatbatch Ltd., Clarence, NY (United States)

    1995-03-01

    The reliability of the power sources used in implantable cardiac defibrillators is critical due to the life-saving nature of the device. Achieving a high reliability power source depends on several systems functioning together. Appropriate cell design is the first step in assuring a reliable product. Qualification of critical components and of the cells using those components is done prior to their designation as implantable grade. Product consistency is assured by control of manufacturing practices and verified by sampling plans using both accelerated and real-time testing. Results to date show that lithium/silver vanadium oxide cells used for implantable cardiac defibrillators have a calculated maximum random failure rate of 0.005% per test month. (orig.)

  4. Reliability systems for implantable cardiac defibrillator batteries

    Science.gov (United States)

    Takeuchi, Esther S.

    The reliability of the power sources used in implantable cardiac defibrillators is critical due to the life-saving nature of the device. Achieving a high reliability power source depends on several systems functioning together. Appropriate cell design is the first step in assuring a reliable product. Qualification of critical components and of the cells using those components is done prior to their designation as implantable grade. Product consistency is assured by control of manufacturing practices and verified by sampling plans using both accelerated and real-time testing. Results to date show that lithium/silver vanadium oxide cells used for implantable cardiac defibrillators have a calculated maximum random failure rate of 0.005% per test month.

  5. Design and assessment of cardiac SPECT systems

    Science.gov (United States)

    Lee, Chih-Jie

    Single-photon emission computed tomography (SPECT) is a modality widely used to detect myocardial ischemia and myocardial infarction. Objectively assessing and comparing different SPECT systems is important so that the best detectability of cardiac defects can be achieved. Whitaker, Clarkson, and Barrett's study on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than reconstruction data. Thus, this observer model assesses overall hardware performance independent by any reconstruction algorithm. In addition, we will show that the run time of image-quality studies is significantly reduced. Several systems derived from the GE CZT-based dedicated cardiac SPECT camera Discovery 530c design, which is officially named the Alcyone Technology: Discovery NM 530c, were assessed using the performance of the SLO for the task of detecting cardiac defects and estimating the properties of the defects. Clinically, hearts can be virtually segmented into three coronary artery territories: left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA). One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can correctly predict in which territory the defect exists. A good estimation of the defect extent from the images is also very helpful for determining the seriousness of the myocardial ischemia. In this dissertation, both locations and extent of defects were estimated by the SLO, and system performance was assessed using localization receiver operating characteristic (LROC) / estimation receiver operating characteristic (EROC) curves. Area under LROC curve (AULC) / area under EROC curve (AUEC) and true positive fraction (TPF) at specific false positive fraction (FPF) can be treated as the gures of merit (FOMs). As the results will show, a

  6. Battery Energy Storage System for PV Output Power Leveling

    OpenAIRE

    Rajkiran Singh; Seyedfoad Taghizadeh; Nadia Mei Lin Tan; Jagadeesh Pasupuleti

    2014-01-01

    Fluctuating photovoltaic (PV) output power reduces the reliability in power system when there is a massive penetration of PV generators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be utilized for compensating the fluctuating PV power. This paper presents a grid connected energy storage system based on a 2 kW full-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper propos...

  7. Output Current Ripple Reduction Algorithms for Home Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Jin-Hyuk Park

    2013-10-01

    Full Text Available This paper proposes an output current ripple reduction algorithm using a proportional-integral (PI controller for an energy storage system (ESS. In single-phase systems, the DC/AC inverter has a second-order harmonic at twice the grid frequency of a DC-link voltage caused by pulsation of the DC-link voltage. The output current of a DC/DC converter has a ripple component because of the ripple of the DC-link voltage. The second-order harmonic adversely affects the battery lifetime. The proposed algorithm has an advantage of reducing the second-order harmonic of the output current in the variable frequency system. The proposed algorithm is verified from the PSIM simulation and experiment with the 3 kW ESS model.

  8. Output Current Ripple Reduction Algorithms for Home Energy Storage Systems

    OpenAIRE

    Jin-Hyuk Park; Kyo-Beum Lee; Hae-Gwang Jeong

    2013-01-01

    This paper proposes an output current ripple reduction algorithm using a proportional-integral (PI) controller for an energy storage system (ESS). In single-phase systems, the DC/AC inverter has a second-order harmonic at twice the grid frequency of a DC-link voltage caused by pulsation of the DC-link voltage. The output current of a DC/DC converter has a ripple component because of the ripple of the DC-link voltage. The second-order harmonic adversely affects the battery lifetime. The propos...

  9. Noninvasive ambulatory measurement system of cardiac activity.

    Science.gov (United States)

    Pino, Esteban J; Chavez, Javier A P; Aqueveque, Pablo

    2015-08-01

    This work implements a noninvasive system that measures the movements caused by cardiac activity. It uses unobtrusive Electro-Mechanical Films (EMFi) on the seat and on the backrest of a regular chair. The system detects ballistocardiogram (BCG) and respiration movements. Real data was obtained from 54 volunteers. 19 of them were measured in the laboratory and 35 in a hospital waiting room. Using a BIOPAC acquisition system, the ECG was measured simultaneously to the BCG for comparison. Wavelet Transform (WT) is a better option than Empirical Mode Decomposition (EMD) for signal extraction and produces higher effective measurement time. In the laboratory, the best results are obtained on the seat. The correlation index was 0.9800 and the Bland-Altman limits of agreement were 0.7136 ± 4.3673 [BPM]. In the hospital waiting room, the best results are also from the seat sensor. The correlation index was 0.9840, and the limits of agreement were 0.4386 ± 3.5884 [BPM]. The system is able to measure BCG in an unobtrusive way and determine the cardiac frequency with high precision. It is simple to use, which means the system can easily be used in non-standard settings: resting in a chair or couch, at the gym, schools or in a hospital waiting room, as shown. PMID:26738057

  10. Global sampled-data output feedback stabilisation for a class of nonlinear systems with unknown output function

    Science.gov (United States)

    Zhai, Jun-yong; Du, Hai-bo; Fei, Shu-min

    2016-03-01

    This paper discusses the problem of global sampled-data output feedback stabilisation for a class of nonlinear systems whose output function is unknown. A systematic design scheme is developed to construct a linear output feedback control law in sampled-data form. An explicit formula for the maximum allowable sampling period is computed to guarantee global stability of the uncertain nonlinear systems under the proposed controller with appropriate gains. Two examples are given to demonstrate the effectiveness of the proposed design procedure.

  11. Evaluating Multi-Input/Multi-Output Digital Control Systems

    Science.gov (United States)

    Pototzky, Anthony S.; Wieseman, Carol D.; Hoadley, Sherwood T.; Mukhopadhyay, Vivek

    1994-01-01

    Controller-performance-evaluation (CPE) methodology for multi-input/multi-output (MIMO) digital control systems developed. Procedures identify potentially destabilizing controllers and confirm satisfactory performance of stabilizing ones. Methodology generic and used in many types of multi-loop digital-controller applications, including digital flight-control systems, digitally controlled spacecraft structures, and actively controlled wind-tunnel models. Also applicable to other complex, highly dynamic digital controllers, such as those in high-performance robot systems.

  12. Gene Regulatory Networks in Cardiac Conduction System Development

    OpenAIRE

    Munshi, Nikhil V.

    2012-01-01

    The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Given its critical role in coordinating cardiac performance, a detailed analysis of the molecular mechanisms underlying conduction system formation should inform our understanding of arrhythmia pathophysiology and affect the development of novel therapeutic strategies. Historically, the ability to distinguish cells of the conduction system from neighboring working myocyt...

  13. Cardiac output by Doppler echocardiography in the premature baboon: Comparison with radiolabeled microspheres

    International Nuclear Information System (INIS)

    Pulsed-Doppler echocardiography (PDE) is a useful noninvasive method for determining left ventricular output (LVO). However, despite increasingly widespread use in neonatal intensive care units, validation studies in prematures with cardiopulmonary disease are lacking. The purpose of this study was to compare radiolabeled microsphere (RLM) and PDE measurements of LVO, using the critically ill premature baboon as a model of the human neonate. Twenty-two paired RLM and PDE measurements of LVO were obtained in 14 animals between 3 and 24 h of age. Average PDE LVO was 152 ml/min/kg (range, 40-258 ml/min/kg) compared to 158 ml/min/kg (range, 67-278 ml/min/kg) measured by RLM. Linear regression analysis of the paired measurements showed good correlation with a slope near unity (gamma = 0.94x + 4.20, r = 0.91, SEE = 25.7 ml). The authors conclude that PDE determinations of LVO compare well with those measured by RLM in the premature baboon. PDE appears to provide a valid estimate of LVO and should be useful in human prematures with cardiopulmonary distress

  14. Pulsatile flow simulator for comparison of cardiac output measurements by electromagnetic flow meter and thermodilution.

    Science.gov (United States)

    Jebson, P J; Karkow, W S

    1986-01-01

    This study examined a pulsatile flow simulator for the purpose of evaluating two measurement devices, an extracorporeal flow probe with an electromagnetic flow meter and several thermodilution catheters. We measured the performance of these devices in a range of low to high flows. Using either saline or blood as a perfusate, we obtained different results with these fluids (p less than 0.001). Each catheter behaved in a linear manner, although variation occurred among the catheters with both saline (minimum slope 1.090, maximum slope 1.190) and blood (minimum slope 1.107, maximum slope 1.154). An increase in rate and stroke volumes of the simulator did not demonstrate an identifiable trend in error. The thermodilution catheters were most accurate at 5.0 L/min irrespective of rate, stroke volume, or perfusate used. In contrast, the electromagnetic flow meter accurately represented flows across the wide range of outputs examined (2.4 to 10.7 L/min). (Slope with saline 1.091, slope with blood 1.080) Throughout the range of flow, the flow meter gave a calibration line 5% higher with blood than with saline. The results indicate that accurate measurement of pulsatile blood flow can be achieved in vitro with an electromagnetic flow meter using saline as a perfusate, provided a correction factor is determined and applied to convert values for saline to accurate values for blood. PMID:2940345

  15. Use of transesophageal Doppler as a sole cardiac output monitor for reperfusion hemodynamic changes during living donor liver transplantation: An observational study

    Directory of Open Access Journals (Sweden)

    M Hussien

    2011-01-01

    Full Text Available Aims: To report the use of transesophageal Doppler (TED, a minimally invasive cardiac output (COP monitor, before, during and after reperfusion and study its effect on anesthetic management during living donor liver transplantation (LDLT. Setting and Design: A prospective observational study. Methods: A total of 25 consecutive recipients with a MELD score between 15 and 20 were enrolled. Data were recorded at baseline (TB; anhepatic phase (TA; and post-reperfusion - 1, 5, 10 and 30 minutes. Fluid therapy was guided by corrected flow time (FTc of the TED. Packed red blood cells (RBCs were only given when hematocrit was less than 25%. Rotational thromboelastometry (ROTEM and standard laboratory tests were used to guide component blood products requirements. Results: Post-reperfusion, the COP, Cardiac Index (CI and stroke volume (SV increased significantly at all points of measurements; this was associated with a significant decrease in systemic vascular resistance (SVR ( P <.05. Immediately post-reperfusion, for 5 minutes, mean arterial blood pressure (ABP dropped significantly (P<.05, and 14 out of the 25 patients required boluses of epinephrine (10 μg to restore the mean ABP; 3 of the 14 patients required norepinephrine infusion till the end of surgery. Central venous pressure (CVP and urine output (UOP at all measures were maintained adequately with FTc-guided fluid replacement. Eight out of the 25 patients required no blood transfusion, and 4 of the 8 patients required no catecholamine support. Conclusion: TED as a sole monitor for COP was able to present significant and reliable changes in the cardiovascular status of the recipients during reperfusion, which could help to guide fluid- and drug-supportive therapy in this population of patients. This preliminary study needs to be applied on a larger scale.

  16. G16R single nucleotide polymorphism but not haplotypes of the ß2-adrenergic receptor gene alters cardiac output in humans

    DEFF Research Database (Denmark)

    Rokamp, Kim Z; Staalsø, Jonatan M; Gartmann, Martin;

    2013-01-01

    Variation in genes encoding the ß2-adrenergic receptor (ADRB2) and angiotensin-converting enzyme (ACE) may influence Q¿ (cardiac output). The 46G>A (G16R) SNP (single nucleotide polymorphism) has been associated with ß2-mediated vasodilation, but the effect of ADRB2 haplotypes on Q¿ has not been ...

  17. Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants.

    LENUS (Irish Health Repository)

    Leslie, A T F S

    2013-11-01

    To characterize and investigate the relationship between systemic blood flow and pre- and postoperative cerebral electrical activity in preterm neonates undergoing patent ductus arteriosus (PDA) ligation.

  18. Advanced information processing system: Input/output network management software

    Science.gov (United States)

    Nagle, Gail; Alger, Linda; Kemp, Alexander

    1988-01-01

    The purpose of this document is to provide the software requirements and specifications for the Input/Output Network Management Services for the Advanced Information Processing System. This introduction and overview section is provided to briefly outline the overall architecture and software requirements of the AIPS system before discussing the details of the design requirements and specifications of the AIPS I/O Network Management software. A brief overview of the AIPS architecture followed by a more detailed description of the network architecture.

  19. Optimizing Input/Output Using Adaptive File System Policies

    Science.gov (United States)

    Madhyastha, Tara M.; Elford, Christopher L.; Reed, Daniel A.

    1996-01-01

    Parallel input/output characterization studies and experiments with flexible resource management algorithms indicate that adaptivity is crucial to file system performance. In this paper we propose an automatic technique for selecting and refining file system policies based on application access patterns and execution environment. An automatic classification framework allows the file system to select appropriate caching and pre-fetching policies, while performance sensors provide feedback used to tune policy parameters for specific system environments. To illustrate the potential performance improvements possible using adaptive file system policies, we present results from experiments involving classification-based and performance-based steering.

  20. Battery Energy Storage System for PV Output Power Leveling

    Directory of Open Access Journals (Sweden)

    Rajkiran Singh

    2014-01-01

    Full Text Available Fluctuating photovoltaic (PV output power reduces the reliability in power system when there is a massive penetration of PV generators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be utilized for compensating the fluctuating PV power. This paper presents a grid connected energy storage system based on a 2 kW full-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper proposes two controllers: a current controller using the d-q synchronous reference and a phase-shift controller. The main function of the current controller is to regulate the voltage at the high-side dc, so that the voltage ratio of the high-voltage side (HVS with low-voltage side (LVS is equal to the transformer turns ratio. The phase-shift controller is employed to manage the charging and discharging modes of the battery based on PV output power and battery voltage. With the proposed system, unity power factor and efficient active power injection are achieved. The feasibility of the proposed control system is investigated using PSCAD simulation.

  1. Diesel Exhaust Inhalation Increases Cardiac Output, Bradyarrhythmias, and Parasympathetic Tone in Aged Heart Failure-Prone Rats

    Science.gov (United States)

    Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance...

  2. New concept input and output systems for high power gyroklystron

    International Nuclear Information System (INIS)

    In order to obtain the high mode purity of a TE011 mode in an overmoded gyroklystron input cavity while maintaining high coupling efficiency, a coaxial dual-cavity input structure with an outer TE411 mode and an inner TE011 mode coaxial cavity has been designed to get a reasonable low Q and to avoid mode distortion due to a single coupling aperture between an input waveguide and input cavity. A quality factor of 73 and a resonant frequency of 8.570 GHz with high mode purity have been obtained for the inner TE011 mode coaxial cavity. Furthermore, in order to inject the output power of a second harmonic gyroklystron (17.136 GHz) into our future pulse composer and accelerator system, a coaxial TE021 output cavity with a TE02-TE01 mode converter is proposed and designed as the output structure of the gyroklystron. The output power can be extracted radially, and at the same time the TE02 mode is converted to TE01 mode into a inner coaxial waveguide. copyright 1999 American Institute of Physics

  3. New concept input and output systems for high power gyroklystron

    Science.gov (United States)

    Xu, Xiaoxi; Lawson, W.; Liu, C.; Cheng, J.; Anderson, J.; Hogan, B.; Granatstein, V. L.; Reiser, M.

    1999-07-01

    In order to obtain the high mode purity of a TE011 mode in an overmoded gyroklystron input cavity while maintaining high coupling efficiency, a coaxial dual-cavity input structure with an outer TE411 mode and an inner TE011 mode coaxial cavity has been designed to get a reasonable low Q and to avoid mode distortion due to a single coupling aperture between an input waveguide and input cavity. A quality factor of 73 and a resonant frequency of 8.570 GHz with high mode purity have been obtained for the inner TE011 mode coaxial cavity. Furthermore, in order to inject the output power of a second harmonic gyroklystron (17.136 GHz) into our future pulse composer and accelerator system, a coaxial TE021 output cavity with a TE02-TE01 mode converter is proposed and designed as the output structure of the gyroklystron. The output power can be extracted radially, and at the same time the TE02 mode is converted to TE01 mode into a inner coaxial waveguide.

  4. New concept input and output systems for high power gyroklystron

    Energy Technology Data Exchange (ETDEWEB)

    Xu, X.; Lawson, W.; Liu, C.; Cheng, J.; Anderson, J.; Hogan, B.; Granatstein, V.L.; Reiser, M. [Institute for Plasma Research and Electrical Engineering Department, University of Maryland, College Park, Maryland 20742 (United States)

    1999-07-01

    In order to obtain the high mode purity of a TE{sub 011} mode in an overmoded gyroklystron input cavity while maintaining high coupling efficiency, a coaxial dual-cavity input structure with an outer TE{sub 411} mode and an inner TE{sub 011} mode coaxial cavity has been designed to get a reasonable low Q and to avoid mode distortion due to a single coupling aperture between an input waveguide and input cavity. A quality factor of 73 and a resonant frequency of 8.570 GHz with high mode purity have been obtained for the inner TE{sub 011} mode coaxial cavity. Furthermore, in order to inject the output power of a second harmonic gyroklystron (17.136 GHz) into our future pulse composer and accelerator system, a coaxial TE{sub 021} output cavity with a TE{sub 02}-TE{sub 01} mode converter is proposed and designed as the output structure of the gyroklystron. The output power can be extracted radially, and at the same time the TE{sub 02} mode is converted to TE{sub 01} mode into a inner coaxial waveguide. {copyright} {ital 1999 American Institute of Physics.}

  5. The non-invasive and continuous estimation of cardiac output using a photoplethysmogram and electrocardiogram during incremental exercise

    International Nuclear Information System (INIS)

    Cardiac output (CO) monitoring is not only essential for critically ill patients in the hospital, but also for patients at home and those undergoing cardiopulmonary exercise testing. However, CO is difficult to monitor during daily activities and exercise. In this paper, we aim at developing a novel CO estimation method that can be used under these challenging conditions. The tube model was utilized to derive a CO index, namely the pulse time reflection ratio (PTRR) from an electrocardiogram and photoplethysmogram. After calibration, the PTRR can be used to estimate beat-to-beat CO. The proposed method was verified against CO measured by impedance cardiography on 19 healthy subjects in an incremental intensity exercise test. Results showed that there were strong correlations (r) between the PTRR and reference CO in 18 subjects (mean r: 0.88, n = 245 trials). Two calibration approaches reported in the literature were applied to the proposed method and the corresponding bias ± precisions of estimation errors were 0 ± 1.89 L min−1 and −0.22 ± 2.12 L min−1, respectively. The percent errors were 21.94% and 24.90%, smaller than the clinical acceptance limit (30%). To conclude, after calibration, this method can be used to monitor CO on healthy subjects during incremental intensity exercise

  6. Cardiac output obtained from test bolus injections as a factor in contrast injection rate revision of following coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Konno, Masahiko [Division of Diagnostic Image Analysis, Graduate School of Medicine, Tohoku University, Miyagi (Japan); Yamagata Prefecture Comprehensive Rehabilitation and Education Center, Yamagata (Japan)], E-mail: mkonno@med.tohoku.ac.jp; Hosokai, Yoshiyuki; Usui, Akihito; Abe, Mitsuya; Tateishi, Toshiki; Kawasumi, Yusuke; Saito, Haruo [Division of Diagnostic Image Analysis, Graduate School of Medicine, Tohoku University, Miyagi (Japan); Tsuda, Masashi; Ota, Hideki; Takase, Kei [Division of Diagnostic Radiology, Graduate School of Medicine, Tohoku University, Miyagi (Japan)

    2012-12-15

    Background.. Optimal contrast enhancement is crucial for the detection of coronary artery stenoses and atherosclerotic changes in coronary CT angiography (CTA). Purpose To demonstrate the feasibility of using the cardiac output (CO) obtained from the test bolus injection data-set (CO test) as a factor in contrast injection rate revision of the following coronary CTA. Material and Methods. The test bolus injection data-sets of 52 consecutive coronary CTAs were examined. CO test was calculated from the test bolus data-set. Aortic peak enhancement (APE) was measured on the following coronary CTA. We simulated the APE at a fixed contrast injection rate of 4 mL/s (simAPE) in each patient. Results. The ranges of COtest and simAPE were 2.82-7.56 L/min and 194-527 Hounsfield Units, respectively. There was a significant negative correlation (R = -0.802, P < 0.001) between simAPE and COtest. Conclusion. COtest can be used for injection rate revision on coronary CTA.

  7. Comparison of cardiac output of the left and right side of the heart by ultrafast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wolfkiel, C.J.; Ferguson, J.L.; Law, W.R.; Chomka, E.V.; Brundage, B.H.

    1986-03-05

    Ultrafast computed tomography (CT) evaluation of cardiac output (CO) can be determined using indicator dilution theory. The concentration of an iodinated contrast agent injected into a vein of a subject can be measured as a function of time by serial EKG, gated CT imaging. The contrast density of the blood pool measured by CT defines the indicator concentration. CT CO is proportional to the area under a time density curve from a region of the blood pool. Proper subject position and scanning timing allows CT to measure CO in the pulmonary (PA) artery and the aorta (AO) with the same contrast bolus. Three anesthetized dogs were multiply scanned following simultaneous injections of contrast and radioactive tracer microspheres. Microsphere CO was determined by reference withdrawal method. Multiple thermodilution CO measurements were made just prior and after each CT CO procedure. 24 comparisons were made of thermodilution, microsphere and CT CO measured in the PA (right sided CO (RSCO)) and the AO (left sided CO (LSCO)). CT CO was calculated as the ratio of the volume of contrast injected to the time density curve area corrected for the relation of contrast density to CT number. RSCO agreed very closely to LSCO (r = .99, p < .001; y = 1.0x +/- .32). RSCO correlated to thermodilution (r = .96, p < .001; y = 1.2x +/- 1.3) and microsphere CO (r = .93, p < .001; y = .69x +/- 1.3). These data show that CT CO measurements can be made in the PA and AO with equal accuracy.

  8. General-Purpose Data-Formatting Input/Output System

    Science.gov (United States)

    Busquets, Anthony M.; Hogge, Thomas W.

    1990-01-01

    Multiplexable input/output (I/O) system developed as interface between host computer and real-time, fixed-base simulator cockpit. Unit designed to be general-purpose interface and operated through virtually any 8- or 16-bit, transistor/transistor-logic-level, parallel-I/O port with or without handshaking. Accepts byte-coded data in form of data blocks from host computer and routes data to various system I/O modules like discrete outputs, lamp drivers, and seven-segment-display drivers. Formats and routes data from input modules back to host computer. Other modules designed to drive alphanumeric displays and communications interfaces and to serve as analog-to-digital and digital-to-analog converter modules.

  9. Non-invasive measurement of cardiac output by a single breath constant expiratory technique.

    OpenAIRE

    1984-01-01

    A new single breath test has been developed that measures pulmonary blood flow (Qc) and pulmonary tissue volume by using the fact that Qc is proportional to the relationship between the absorption rate of acetylene (C2H2) from the alveolar gas and the rate of change of lung volume during constant expiratory flow. To make these measurements a bag in bottle system with a rolling seal spirometer, a mass spectrometer, and a minicomputer with analogue to digital conversion have been used. Qc was c...

  10. Quantitative Feedback Control of Multiple Input Single Output Systems

    OpenAIRE

    Javier Rico-Azagra; Montserrat Gil-Martínez; Jorge Elso

    2014-01-01

    This paper presents a robust feedback control solution for systems with multiple manipulated inputs and a single measurable output. A structure of parallel controllers achieves robust stability and robust disturbance rejection. Each controller uses the least possible amount of feedback at each frequency. The controller design is carried out in the Quantitative Feedback Theory framework. The method pursues a smart load sharing along the frequency spectrum, where each branch must either coll...

  11. Output feedback for linear multivariable systems with parameter uncertainty.

    Science.gov (United States)

    Basuthakur, S.; Knapp, C. H.

    1973-01-01

    A minimax design method is applied to the problem of obtaining an acceptable output feedback matrix for linear multivariable systems with parameter uncertainty. The result is a set of nonlinear matrix equations (similar to those obtained by Levine and Athans (1970)), which must be solved for the feedback matrix. An example illustrates the technique and the fact that better results are achieved for large parameter variation than with a purely nominal design.

  12. Optimizing the output-photon entanglement in multimode optomechanical systems

    Science.gov (United States)

    Deng, Zhi Jiao; Yan, Xiao-Bo; Wang, Ying-Dan; Wu, Chun-Wang

    2016-03-01

    Entangled light beams are important resources for quantum information processing. For some applications like teleportation, only the entanglement between two wave packets (two harmonic oscillators) is needed. So the calculation of output-photon entanglement involves projecting continuous output modes onto wave-packet modes by filter functions, thus resulting in a strong dependence of entanglement on the filter functions. In this paper, we aim at optimizing the filter functions to obtain a large entanglement in a relatively short time, which is important for utilizing the entangled light beams more efficiently in real experiments. We outline the general optimization procedures based on our previous schemes of generating entangled beams in a multimode optomechanical system. Moreover, we give analytic insights into as well as physical explanations of the wave-packet optimization, which are helpful for experimental estimations.

  13. DBS -- An rlogin multiplexer and output logger for DA systems

    International Nuclear Information System (INIS)

    DART Bootstrap Services (dbs) is the first component of run-control for the DART Data Acquisition system -- the DA for the 96' round of experiments at Fermilab -- though it has potential usefulness as a powerful tool in other distributed applications. dbs is an rlogin session multiplexer. It allows a user, running a single program, to start up any number of remote login sessions, feed shell commands to them, and collect their output into a single (or multiple) log files (a server keeps the sessions open and collects their output). From this program, any session can be attached to interactively so it appears just like an rlogin session -- dbs becomes transparent. When finished with this interactive mode, the user can escape back to dbs and attach to a different session if so desired. Among many other useful features, dbs supplies a mechanism for cleanup (deletion) of all processes created under a session, allowing a fresh start

  14. System convergence in transport models: algorithms efficiency and output uncertainty

    DEFF Research Database (Denmark)

    Rich, Jeppe; Nielsen, Otto Anker

    2015-01-01

    Transport models most often involve separate models for traffic assignment and demand. As a result, two different equilibrium mechanisms are involved, (i) the internal traffic assignment equilibrium, and (ii) the external equilibrium between the assignment model and the demand model. The objective...... of this paper is to analyse convergence performance for the external loop and to illustrate how an improper linkage between the converging parts can lead to substantial uncertainty in the final output. Although this loop is crucial for the performance of large-scale transport models it has not been......-scale in the Danish National Transport Model (DNTM). It is revealed that system convergence requires that either demand or supply is without random noise but not both. In that case, if MSA is applied to the model output with random noise, it will converge effectively as the random effects are gradually...

  15. Global output regulation of a class of lower triangular nonlinear systems with unknown control direction via output feedback

    Science.gov (United States)

    Li, Ranran

    2016-05-01

    In this paper, we study the global output regulation problem of a class of lower triangular systems under measurement output feedback. A novel high-gain filter is proposed to estimate the unmeasured states of the systems. Furthermore, we integrate the robust stabilisation technique and Nussbaumgain technique to achieve asymptotic regulation when the control direction is unknown. The simulation results illustrate the effectiveness of the proposed method.

  16. Output synchronization of chaotic systems under nonvanishing perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Mancilla, Didier [Departamento de Ciencias Exactas y Tecnologicas, Centro Universitario de los Lagos, Universidad de Guadalajara (CULagos-UdeG), Enrique Diaz de Leon s/n, 47460 Lagos de Moreno, Jal. (Mexico)], E-mail: didier@uabc.mx; Cruz-Hernandez, Cesar [Electronics and Telecommunications Department, Scientific Research and Advanced Studies of Ensenada (CICESE), Km. 107, Carretera Tijuana-Ensenada, 22860 Ensenada, B.C. (Mexico)], E-mail: ccruz@cicese.mx

    2008-08-15

    In this paper, an analysis for chaos synchronization under nonvanishing perturbations is presented. In particular, we use model-matching approach from nonlinear control theory for output synchronization of identical and nonidentical chaotic systems under nonvanishing perturbations in a master-slave configuration. We show that the proposed approach is indeed suitable to synchronize a class of perturbed slaves with a chaotic master system; that is the synchronization error trajectories remain bounded if the perturbations satisfy some conditions. In order to illustrate this robustness synchronization property, we present two cases of study: (i) for identical systems, a pair of coupled Roessler systems, the first like a master and the other like a perturbed slave, and (ii) for nonidentical systems, a Chua's circuit driving a Roessler/slave system with a perturbed control law, in both cases a quantitative analysis on the perturbation is included.

  17. Output feedback control of a mechanical system using magnetic levitation.

    Science.gov (United States)

    Beltran-Carbajal, F; Valderrabano-Gonzalez, A; Rosas-Caro, J C; Favela-Contreras, A

    2015-07-01

    This paper presents an application of a nonlinear magnetic levitation system to the problem of efficient active control of mass-spring-damper mechanical systems. An output feedback control scheme is proposed for reference position trajectory tracking tasks on the flexible mechanical system. The electromagnetically actuated system is shown to be a differentially flat nonlinear system. An extended state estimation approach is also proposed to obtain estimates of velocity, acceleration and disturbance signals. The differential flatness structural property of the system is then employed for the synthesis of the controller and the signal estimation approach presented in this work. Some experimental and simulation results are included to show the efficient performance of the control approach and the effective estimation of the unknown signals. PMID:25707718

  18. Recent advances in cardiac SPECT instrumentation and system design.

    Science.gov (United States)

    Smith, Mark F

    2013-08-01

    Recent advances in clinical cardiac SPECT instrumentation are reviewed from a systems perspective. New hardware technologies include pixelated scintillator and semiconductor detector elements; photodetectors such as position-sensitive photomultiplier tubes (PSPMT), avalanche photodiodes (APD) and silicon photomultipliers (SiPM); and novel cardiac collimation methods. There are new approaches for positioning detectors and controlling their motion during cardiac imaging. Software technology advances include iterative image reconstruction with modeling of Poisson statistics and depth-dependent collimator response. These new technologies enable faster acquisitions, the lowering of administered activity and radiation dose, and improved image resolution. Higher sensitivity collimators are a significant factor enabling faster acquisitions. Several clinical systems incorporating new technologies are discussed and different system designs can achieve similar performance. With detector elements such as APDs, SiPMs and semiconductors that are insensitive to magnetic fields, the potential for cardiac SPECT imagers that are MRI compatible opens up new frontiers in clinical cardiac research and patient care. PMID:23832650

  19. Risk stratification systems in cardiac surgery

    Directory of Open Access Journals (Sweden)

    G. Tinică

    2012-08-01

    Full Text Available n medicine, as in any other field, quality is a prerequisite of competitiveness. In this paper we do a brief description and definition of commonly used preoperative risk scores for heart surgery with regard to their predictive values and clinical applicability for current population. Although most of the selected score systems were primarily designed to predict mortality, postoperative morbidity has been acknowledged as the major determinant of hospital cost and quality of life after surgery. Any method of evaluation and optimization of quality is based on a risk stratification system. Risk system development and their application in current medical practice have become increasingly popular in the recent years because of the many therapeutic options available for some cardiovascular diseases, which until now were considered difficult to address, due to technical advances that are enabling risk taking. Risk stratification is a powerful decision-making tool and should represent an incumbent part of the cardiac surgical practice, just like the knowledge of anatomy and the practice of surgical techniques. These models also play an increasingly important role in risk management and performance measurement processes like quality analysis, meaningful comparison of outcomes, and identifying the optimal relationship between cost, quality of medical care and efficiency.

  20. Addressing Assumptions for the Use of Non-invasive Cardiac Output Measurement Techniques During Exercise in COPD.

    Science.gov (United States)

    Perrault, Hélène; Richard, Ruddy; Kapchinsky, Sophia; Baril, Jacinthe; Bourbeau, Jean; Taivassalo, Tanja

    2016-01-01

    The multifactorial functional limitation of COPD increasingly demonstrates the need for an integrated circulatory assessment. In this study cardiac output (Qc) derived from non-inert (CO2-RB), inert (N2O-RB) gas rebreathing approaches and bioimpedance were compared to examine the limitations of currently available non-invasive techniques for exercise Qc determination in patients with chronic lung disease. Thirteen COPD patients (GOLD II-III) completed three constant cycling bouts at 20, 35, and 50% of peak work on two occasions to assess Qc with bioimpedance as well as using CO2-RB and N2O-RB for all exercise tests. Results showed significantly lower Qc using the N2O-RB or end-tidal CO2-derived Qc compared to the PaCO2-derived CO2-RB or the bioimpedance at rest and for all exercise intensities. End-tidal CO2-derived values are however not statistically different from those obtained using inert-gas rebreathing. This study show that in COPD patients, CO2-rebreathing Qc values obtained using PaCO2 contents which account for any gas exchange impairment or inadequate gas mixing are similar to those obtained using thoracic bioimpedance. Alternately, the lower values for N2O rebreathing derived Qc indicates the inability of this technique to account for gas exchange impairment in the computation of Qc. These findings indicate that the choice of a gas rebreathing technique to measure Qc in patients must be dictated by the ability to include in the derived computations a correction for either gas exchange inadequacies and/or a vascular shunt. PMID:26408087

  1. The effects of cardiac output and pulmonary arterial hypertension on volumetric capnography derived-variables during normoxia and hypoxia.

    Science.gov (United States)

    Mosing, Martina; Kutter, Annette P N; Iff, Samuel; Raszplewicz, Joanna; Mauch, Jacqueline; Bohm, Stephan H; Tusman, Gerardo

    2015-02-01

    The aim of this study was to test the effect of cardiac output (CO) and pulmonary artery hypertension (PHT) on volumetric capnography (VCap) derived-variables. Nine pigs were mechanically ventilated using fixed ventilatory settings. Two steps of PHT were induced by IV infusion of a thromboxane analogue: PHT25 [mean pulmonary arterial pressure (MPAP) of 25 mmHg] and PHT40 (MPAP of 40 mmHg). CO was increased by 50% from baseline (COup) with an infusion of dobutamine≥5 μg kg(-1) min(-1) and decreased by 40% from baseline (COdown) infusing sodium nitroglycerine≥30 μg kg(-1) min(-1) plus esmolol 500 μg kg(-1) min(-1). Another state of PHT and COdown was induced by severe hypoxemia (FiO2 0.07). Invasive hemodynamic data and VCap were recorded and compared before and after each step using a mixed random effects model. Compared to baseline, the normalized slope of phase III (SnIII) increased by 32% in PHT25 and by 22% in PHT40. SnIII decreased non-significantly by 4% with COdown. A combination of PHT and COdown associated with severe hypoxemia increased SnIII by 28% compared to baseline. The elimination of CO2 per breath decreased by 7% in PHT40 and by 12% in COdown but increased only slightly with COup. Dead space variables did not change significantly along the protocol. At constant ventilation and body metabolism, pulmonary artery hypertension and decreases in CO had the biggest effects on the SnIII of the volumetric capnogram and on the elimination of CO2. PMID:24908108

  2. Exact-Output Tracking Theory for Systems with Parameter Jumps

    Science.gov (United States)

    Devasia, Santosh; Paden, Brad; Rossi, Carlo

    1997-01-01

    We consider the exact output tracking problem for systems with parameter jumps. Necessary and sufficient conditions are derived for the elimination of switching-introduced output transient. Previous works have studied this problem by developing a regulator that maintains exact tracking through parameter jumps (switches). Such techniques are, however, only applicable to minimum-phase systems. In contrast, our approach is applicable to non-minimum-phase systems and it obtains bounded but possibly non-causal solutions. If the reference trajectories are generated by an exosystem, then we develop an exact-tracking controller in a feed-back form. As in standard regulator theory, we obtain a linear map from the states of the exosystem to the desired system state which is defined via a matrix differential equation. The constant solution of this differential equation provides asymptotic tracking, and coincides with the feedback law used in standard regulator theory. The obtained results are applied to a simple flexible manipulator with jumps in the pay-load mass.

  3. Output feedback regulator design for jet engine control systems

    Science.gov (United States)

    Merrill, W.

    1977-01-01

    A multivariable control design procedure based on the output feedback regulator formulation is described and applied to an F100 turbofan engine model. Full order model dynamics, are incorporated in the example design. The effect of actuator dynamics on closed loop performance is investigated. Also, the importance of turbine inlet temperature as an element of the dynamic feedback is studied. Step responses are given to indicate the improvement in system performance with this control. Calculation times for all experiments are given in CPU seconds for comparison purposes.

  4. The 24 h pattern of arterial pressure in mice is determined mainly by heart rate‐driven variation in cardiac output

    OpenAIRE

    Kurtz, Theodore W.; Lujan, Heidi L.; DiCarlo, Stephen E.

    2014-01-01

    Abstract Few studies have systematically investigated whether daily patterns of arterial blood pressure over 24 h are mediated by changes in cardiac output, peripheral resistance, or both. Understanding the hemodynamic mechanisms that determine the 24 h patterns of blood pressure may lead to a better understanding of how such patterns become disturbed in hypertension and influence risk for cardiovascular events. In conscious, unrestrained C57BL/6J mice, we investigated whether the 24 h patter...

  5. Differences of cardiac output measurements by open-circuit acetylene uptake in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: a cohort study

    Directory of Open Access Journals (Sweden)

    Schwaiblmair Martin

    2012-03-01

    Full Text Available Abstract Background As differences in gas exchange between pulmonary arterial hypertension (PAH and chronic thromboembolic pulmonary hypertension (CTEPH have been demonstrated, we asked if cardiac output measurements determined by acetylene (C2H2 uptake significantly differed in these diseases when compared to the thermodilution technique. Method Single-breath open-circuit C2H2 uptake, thermodilution, and cardiopulmonary exercise testing were performed in 72 PAH and 32 CTEPH patients. Results In PAH patients the results for cardiac output obtained by the two methods showed an acceptable agreement with a mean difference of -0.16 L/min (95% CI -2.64 to 2.32 L/min. In contrast, the agreement was poorer in the CTEPH group with the difference being -0.56 L/min (95% CI -4.96 to 3.84 L/min. Functional dead space ventilation (44.5 ± 1.6 vs. 32.2 ± 1.4%, p 2 gradient (9.9 ± 0.8 vs. 4.1 ± 0.5 mmHg, p Conclusion Cardiac output evaluation by the C2H2 technique should be interpreted with caution in CTEPH, as ventilation to perfusion mismatching might be more relevant than in PAH.

  6. Robust adaptive output feedback control of nonlinearly parameterized systems

    Institute of Scientific and Technical Information of China (English)

    LIU Yusheng; LI Xingyuan

    2007-01-01

    The ideas of adaptive nonlinear damping and changing supply functions were used to counteract the effects of parameter and nonlinear uncertainties,unmodeled dynamics and unknown bounded disturbances.The high-gain observer was used to estimate the state of the system.A robust adaptive output feedback control scheme was proposed for nonlinearly parameterized systems represented by inputoutput models.The scheme does not need to estimate the unknown parameters nor add a dynamical signal to dominate the effects of unmodeled dynamics.It is proven that the proposed control scheme guarantees that all the variables in the closed-loop system are bounded and the mean-square tracking error can be made arbitrarily small by choosing some design parameters appropriately.Simulation results have illustrated the effectiveness of the proposed robust adaptive control scheme.

  7. Output feedback trajectory stabilization of the uncertainty DC servomechanism system.

    Science.gov (United States)

    Aguilar-Ibañez, Carlos; Garrido-Moctezuma, Ruben; Davila, Jorge

    2012-11-01

    This work proposes a solution for the output feedback trajectory-tracking problem in the case of an uncertain DC servomechanism system. The system consists of a pendulum actuated by a DC motor and subject to a time-varying bounded disturbance. The control law consists of a Proportional Derivative controller and an uncertain estimator that allows compensating the effects of the unknown bounded perturbation. Because the motor velocity state is not available from measurements, a second-order sliding-mode observer permits the estimation of this variable in finite time. This last feature allows applying the Separation Principle. The convergence analysis is carried out by means of the Lyapunov method. Results obtained from numerical simulations and experiments in a laboratory prototype show the performance of the closed loop system. PMID:22884179

  8. Blood-Pressure Measuring System Gives Accurate Graphic Output

    Science.gov (United States)

    1965-01-01

    The problem: To develop an instrument that will provide an external (indirect) measurement of arterial blood pressure in the form of an easily interpreted graphic trace that can be correlated with standard clinical blood-pressure measurements. From sphygmograms produced by conventional sphygmographs, it is very difficult to differentiate the systolic and diastolic blood-pressure pulses and to correlate these indices with the standard clinical values. It is nearly impossible to determine these indices when the subject is under physical or emotional stress. The solution: An electronic blood-pressure system, basically similar to conventional ausculatory sphygmomanometers, employing a standard occluding cuff, a gas-pressure source, and a gas-pressure regulator and valve. An electrical output transducer senses cuff pressure, and a microphone positioned on the brachial artery under the occluding cuff monitors the Korotkoff sounds from this artery. The output signals present the conventional systolic and diastolic indices in a clear, graphical display. The complete system also includes an electronic timer and cycle-control circuit.

  9. On input-to-output stability of switched non-exponentially stable nonlinear systems

    OpenAIRE

    Efimov, Denis; Panteley, Elena; Loria, Antonio

    2009-01-01

    The problem of input-to-output stability for switched nonlinear systems is considered. Two approaches for switching between non-exponentially stable systems are proposed guaranteeing input-to-output stability for the switched system.

  10. Robust MPC with Output Feedback of Integrating Systems

    Directory of Open Access Journals (Sweden)

    J. M. Perez

    2012-01-01

    Full Text Available In this work, it is presented a new contribution to the design of a robust MPC with output feedback, input constraints, and uncertain model. Multivariable predictive controllers have been used in industry to reduce the variability of the process output and to allow the operation of the system near to the constraints, where it is usually located the optimum operating point. For this reason, new controllers have been developed with the objective of achieving better performance, simpler control structure, and robustness with respect to model uncertainty. In this work, it is proposed a model predictive controller based on a nonminimal state space model where the state is perfectly known. It is an infinite prediction horizon controller, and it is assumed that there is uncertainty in the stable part of the model, which may also include integrating modes that are frequently present in the process plants. The method is illustrated with a simulation example of the process industry using linear models based on a real process.

  11. Comparison of transthoracic electrical bioimpedance cardiac output measurement with thermodilution method in post coronary artery bypass graft patients

    Directory of Open Access Journals (Sweden)

    Sharma Vikas

    2011-01-01

    Full Text Available Transthoracic electrical bioimpedance (TEB has been proposed as a non-invasive, continuous, and cost-effective method of cardiac output (CO measurement. In this prospective, non-randomized, clinical study, we measured CO with NICOMON (Larsen and Toubro Ltd., Mysore, India and compared it with thermodilution (TD method in patients after off-pump coronary artery bypass (OPCAB graft surgery. We also evaluated the effect of ventilation (mechanical and spontaneous on the measurement of CO by the two methods. Forty-six post-OPCAB patients were studied at five predefined time points during controlled ventilation and at five time points when breathing spontaneously. A total of 230 data pairs of CO were obtained. During controlled ventilation, TD CO values ranged from 2.29 to 6.74 L/min (mean 4.45 ± 0.85 L/min, while TEB CO values ranged from 1.70 to 6.90 L/min (mean 4.43 ± 0.94 L/min. The average correlation (r was 0.548 (P = 0.0002, accompanied by a bias of 0.015 L/min and precision of 0.859 L/min. In spontaneously breathing patients, TD CO values ranged from 2.66 to 6.92 L/min (mean 4.66 ± 0.76 L/min, while TEB CO values ranged from 3.08 to 6.90 L/min (mean 4.72 ± 0.82 L/min. Their average correlation was relatively poor (r = 0.469, P= 0.002, accompanied by a bias of −0.059 L/min and precision of 0.818 L/min. The overall percent errors between TD CO and TEB CO were 19.3% (during controlled ventilation and 17.4% (during spontaneous breathing, respectively. To conclude, a fair correlation was found between TD CO and TEB CO measurements among post-OPCAB patients during controlled ventilation. However, the correlation was weak in spontaneously breathing patients.

  12. External cardiac compression may be harmful in some scenarios of pulseless electrical activity.

    LENUS (Irish Health Repository)

    Hogan, T S

    2012-10-01

    Pulseless electrical activity occurs when organised or semi-organised electrical activity of the heart persists but the product of systemic vascular resistance and the increase in systemic arterial flow generated by the ejection of the left venticular stroke volume is not sufficient to produce a clinically detectable pulse. Pulseless electrical activity encompasses a very heterogeneous variety of severe circulatory shock states ranging in severity from pseudo-cardiac arrest to effective cardiac arrest. Outcomes of cardiopulmonary resuscitation for pulseless electrical activity are generally poor. Impairment of cardiac filling is the limiting factor to cardiac output in many scenarios of pulseless electrical activity, including extreme vasodilatory shock states. There is no evidence that external cardiac compression can increase cardiac output when impaired cardiac filling is the limiting factor to cardiac output. If impaired cardiac filling is the limiting factor to cardiac output and the heart is effectively ejecting all the blood returning to it, then external cardiac compression can only increase cardiac output if it increases venous return and cardiac filling. Repeated cardiac compression asynchronous with the patient\\'s cardiac cycle and raised mean intrathoracic pressure due to chest compression can be expected to reduce rather than to increase cardiac filling and therefore to reduce rather than to increase cardiac output in such circumstances. The hypothesis is proposed that the performance of external cardiac compression will have zero or negative effect on cardiac output in pulseless electrical activity when impaired cardiac filling is the limiting factor to cardiac output. External cardiac compression may be both directly and indirectly harmful to significant sub-groups of patients with pulseless electrical activity. We have neither evidence nor theory to provide comfort that external cardiac compression is not harmful in many scenarios of pulseless

  13. Variance estimation of modal parameters from output-only and input/output subspace-based system identification

    Science.gov (United States)

    Mellinger, Philippe; Döhler, Michael; Mevel, Laurent

    2016-09-01

    An important step in the operational modal analysis of a structure is to infer on its dynamic behavior through its modal parameters. They can be estimated by various modal identification algorithms that fit a theoretical model to measured data. When output-only data is available, i.e. measured responses of the structure, frequencies, damping ratios and mode shapes can be identified assuming that ambient sources like wind or traffic excite the system sufficiently. When also input data is available, i.e. signals used to excite the structure, input/output identification algorithms are used. The use of input information usually provides better modal estimates in a desired frequency range. While the identification of the modal mass is not considered in this paper, we focus on the estimation of the frequencies, damping ratios and mode shapes, relevant for example for modal analysis during in-flight monitoring of aircrafts. When identifying the modal parameters from noisy measurement data, the information on their uncertainty is most relevant. In this paper, new variance computation schemes for modal parameters are developed for four subspace algorithms, including output-only and input/output methods, as well as data-driven and covariance-driven methods. For the input/output methods, the known inputs are considered as realizations of a stochastic process. Based on Monte Carlo validations, the quality of identification, accuracy of variance estimations and sensor noise robustness are discussed. Finally these algorithms are applied on real measured data obtained during vibrations tests of an aircraft.

  14. Genetic and physiologic dissection of the vertebrate cardiac conduction system.

    Directory of Open Access Journals (Sweden)

    Neil C Chi

    2008-05-01

    Full Text Available Vertebrate hearts depend on highly specialized cardiomyocytes that form the cardiac conduction system (CCS to coordinate chamber contraction and drive blood efficiently and unidirectionally throughout the organism. Defects in this specialized wiring system can lead to syncope and sudden cardiac death. Thus, a greater understanding of cardiac conduction development may help to prevent these devastating clinical outcomes. Utilizing a cardiac-specific fluorescent calcium indicator zebrafish transgenic line, Tg(cmlc2:gCaMP(s878, that allows for in vivo optical mapping analysis in intact animals, we identified and analyzed four distinct stages of cardiac conduction development that correspond to cellular and anatomical changes of the developing heart. Additionally, we observed that epigenetic factors, such as hemodynamic flow and contraction, regulate the fast conduction network of this specialized electrical system. To identify novel regulators of the CCS, we designed and performed a new, physiology-based, forward genetic screen and identified for the first time, to our knowledge, 17 conduction-specific mutations. Positional cloning of hobgoblin(s634 revealed that tcf2, a homeobox transcription factor gene involved in mature onset diabetes of the young and familial glomerulocystic kidney disease, also regulates conduction between the atrium and the ventricle. The combination of the Tg(cmlc2:gCaMP(s878 line/in vivo optical mapping technique and characterization of cardiac conduction mutants provides a novel multidisciplinary approach to further understand the molecular determinants of the vertebrate CCS.

  15. Input-Output Parametric Models for Nonlinear Systems. Part ii Stochastic Nonlinear Systems

    OpenAIRE

    Leontaritis, I.J.; Billings, S A

    1984-01-01

    In the first part of this paper (Leontaritis and Billings 1984)recursive input-output models for deterministic nonlinear multivariable discrete-time systems were derived and sufficient conditions for their existence were defined. In this second part, the nonlinear model is compared with other system representations, several examples are introduced and the results are extended to create prediction error input-output models for multivariable nonlinear stochastic systems.

  16. Output-Driven Funding and Budgeting Systems in the Public Sector

    OpenAIRE

    Marc Robinson

    2002-01-01

    Output-driven funding systems are systems in which payments made to service-delivery agencies by government are an explicit function of quantities of outputs delivered by those agencies. This paper considers the feasibility of such systems for the funding tax-financed public services. It focuses upon the implications of key characteristics of public sector outputs, and specifically upon the prevalence of heterogeneous outputs, the predominance of services (as opposed to physical goods), and t...

  17. Cardiac imaging systems and methods employing computerized tomographic scanning

    International Nuclear Information System (INIS)

    The invention relates to cardiac imaging systems and methods employing computerised tomographic scanning. Apparatus is described which allows an image of the radiation attenuation of the heart at a desired phase of the cardiac cycle. The patients ECG signal can be used in a transverse-and-rotate type CT scanner as a time base, so that the beam reaches the heart at a desired phase of the cardiac cycle, or, in a purely rotational-type CT scanner continuously generated scan data is only stored for corresponding phases of successive cardiac cycles. Alternatively, gating of the beams themselves by shuttering or switching the power supply can be controlled by the ECG signal. A pacemaker is used to stabilize the cardiac period. Also used is a system for recognising unacceptable variations in the cardiac period and discarding corresponding scan data. In a transverse-and-rotate type fan-beam CT scanner, the effective beam width is narrowed to reduce the duration of the traverse of the heart. (U.K.)

  18. Variability in the Cardiac Venous System of Wistar Rats

    Science.gov (United States)

    Krešáková, Lenka; Purzyc, Halina; Schusterová, Ingrid; Fulton, Benjamin; Maloveská, Marcela; Vdoviaková, Katarina; Kravcová, Zuzanna; Boldižár, Martin

    2015-01-01

    Rats are often used as animal models in experimental cardiology for studying myocardial infarctions and various cardiologic procedures. Currently the cardiac venous system is a target for the delivery of drugs, gene vectors, angiogenetic growth factors, stem cells, and cardioprotective reagents. The purpose of this study was to describe the anatomic configuration and variability of the cardiac venous system in Wistar rats, by using the corrosion cast method and perfusion of colored latex. The distribution of veins in the rat heart disagrees with prior descriptions for other mammals, except mice, which have a similar pattern. Coronary venous drainage in the 36 rats examined consistently involved the left cardiac, left conal, major caudal, right cardiac, and right conal veins. Other veins involved inconsistently included the cranial cardiac vein (58.3% of cases), minor caudal veins (16.7%), conoanastomotic vein (66.7%), and left atrial vein (75%). In 4 cases (11.1%), the collateral veins were located between the left conal and left cardiac veins. In this study, high morphologic variability between cases was manifested by differences in the arrangement, size, mode of opening, and formation of the common root and affected all regions of the heart but primarily the right ventricle. PMID:25651085

  19. Output-back fuzzy logic systems and equivalence with feedback neural networks

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new idea, output-back fuzzy logic systems, is proposed. It is proved that output-back fuzzy logic systems must be equivalent to feedback neural networks. After the notion of generalized fuzzy logic systems is defined, which contains at least a typical fuzzy logic system and an output-back fuzzy logic system, one important conclusion is drawn that generalized fuzzy logic systems are almost equivalent to neural networks.

  20. Method and system for managing an electrical output of a turbogenerator

    Science.gov (United States)

    Stahlhut, Ronnie Dean; Vuk, Carl Thomas

    2009-06-02

    The system and method manages an electrical output of a turbogenerator in accordance with multiple modes. In a first mode, a direct current (DC) bus receives power from a turbogenerator output via a rectifier where turbogenerator revolutions per unit time (e.g., revolutions per minute (RPM)) or an electrical output level of a turbogenerator output meet or exceed a minimum threshold. In a second mode, if the turbogenerator revolutions per unit time or electrical output level of a turbogenerator output are less than the minimum threshold, the electric drive motor or a generator mechanically powered by the engine provides electrical energy to the direct current bus.

  1. A Case of Femoral Arteriovenous Fistula Causing High-Output Cardiac Failure, Originally Misdiagnosed as Chronic Fatigue Syndrome

    OpenAIRE

    Porter, J; Al-Jarrah, Q.; Richardson, S

    2014-01-01

    Percutaneous arterial catheterisation is commonly undertaken for a range of diagnostic and interventional procedures. Iatrogenic femoral arteriovenous fistulas are an uncommon complication of these procedures. Most are asymptomatic and close spontaneously, but can rarely increase in size leading to the development of symptoms. We report a case of an iatrogenic femoral arteriovenous fistula, causing worsening congestive cardiac failure, in a 34-year-old marathon runner. This was originally dia...

  2. Uncalibrated pulse power analysis fails to reliably measure cardiac output in patients undergoing coronary artery bypass surgery

    OpenAIRE

    Broch, Ole; Renner, Jochen; Höcker, Jan; Gruenewald, Matthias; Meybohm, Patrick; Schöttler, Jan; Steinfath, Markus; Bein, Berthold

    2011-01-01

    Introduction Uncalibrated arterial pulse power analysis has been recently introduced for continuous monitoring of cardiac index (CI). The aim of the present study was to compare the accuracy of arterial pulse power analysis with intermittent transpulmonary thermodilution (TPTD) before and after cardiopulmonary bypass (CPB). Methods Forty-two patients scheduled for elective coronary surgery were studied after induction of anaesthesia, before and after CPB respectively. Each patient was monitor...

  3. Precipitation output of INCA system: evaluation and use

    Science.gov (United States)

    Kyznarova, Hana; Novak, Petr; Brezkova, Lucie; Janal, Petr; Salek, Milan

    2013-04-01

    INCA is a system that provides detailed analysis of current weather and improves NWP forecasts by using latest information from meteorological stations, radars, sounding and satellite data. It was developed by the Zentralanstalt für Meteorologie und Geodynamik in Austria and provided for use by other countries. The Czech Hydrometeorological Institute (CHMI) uses adapted version of the INCA system (INCA-CZ) in the frame of INCA-CE project. This contribution presents the first results of use of INCA-CZ precipitation module for quantitative precipitation analysis (QPE) and forecast (QPF) and their comparison with the algorithms currently used by the CHMI. Testing of the INCA-CZ precipitation output is focused on QPE and QPF up to 3 hours, since INCA is tested and used as an input into hydrological model for flash flood forecasting. INCA-CZ QPE was compared with algorithms used by the CHMI for QPE (based on conditional merging (CM) and on kriging with external drift (KED)). The comparison was carried out on 10 minute and 1 hour precipitation data. Generally 10 minute precipitation sums are burdened by higher uncertainties than 1 hour precipitation data, still they are very useful when used in convective situations and when we try to forecast highly localized flash floods. Preliminary results suggest that INCA-CZ QPE is comparable with QPEs used by the CHMI. As expected, the performance of the algorithms when using 10 minute data is generally worse than for 1 hour precipitation sums. INCA-CZ QPF was compared with the QPF made by the CHMI implementation of the COTREC algorithm. COTREC algorithm is operatively applied on the CHMI radar data. 1 hour QPEs computed by KED algorithm and INCA-CZ were used as the true values. QPFs of average 1hour precipitation sums computed over 119 operative catchments were compared. The forecasted sums were computed over 0-1, 1-2, 2-3 hour. Quality indices CSI, FAR and POD for 0.1mm and 1.0mm thresholds were used. CSI values of both INCA

  4. Low cardiac output as physiological phenomenon in hibernating, free-ranging Scandinavian brown bears (Ursus arctos) - an observational study

    DEFF Research Database (Denmark)

    Jørgensen, Peter Godsk; Arnemo, Jon; Swenson, Jon E;

    2014-01-01

    cardiac function associated with metabolic depression in the hibernating vs. active states in free-ranging Scandinavian brown bears. METHODS: We performed echocardiography on seven free-ranging brown bears in Dalarna, Sweden, anesthetized with medetomidine-zolazepam-tiletamine-ketamine during winter....... CONCLUSION: Free-ranging brown bears demonstrate hemodynamics comparable to humans during active state, whereas during hibernation, we documented extremely low-flow hemodynamics. Understanding these physiological changes in bears may help to gain insight into the mechanisms of cardiogenic shock and heart...

  5. Cardiac and systemic haemodynamic complications of liver cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens H; Møller, Søren

    2009-01-01

    physical and pharmacological strain. Cardiac failure is an important cause of mortality after liver transplantation and stressful procedures as insertions of transjugular intrahepatic portal systemic shunt (TIPS), peritoneal venous shunting, and other types of surgery. Improvement of liver function has......Cardiovascular complications of liver cirrhosis include cardiac dysfunction and abnormalities in the central-, splanchnic,- and peripheral circulation. Vasodilatation prevails, but vascular beds with various degrees of reduced and increased haemodynamic resistance are the results of massive...... been shown to reverse the cardiovascular complications. The clinical significance is an important topic for future research. At present, no specific treatment can be recommended, and the cardiac failure in cirrhosis should be treated as in non-cirrhotic patients with sodium restriction, diuretics, and...

  6. A Visualization System for Interactive Exploration of the Cardiac Anatomy.

    Science.gov (United States)

    Zhang, Lei; Wang, Kuanquan; Yang, Fei; Lu, Wenjing; Wang, Kechao; Zhang, Yue; Liang, Xiaoqing; Han, Dongchen; Zhu, Ying Julie

    2016-06-01

    Because of the complex and fine structure, visualization of the heart still remains a challenging task, which makes it an active research topic. In this paper, we present a visualization system for medical data, which takes advantage of the recent graphics processing unit (GPU) and can provide real-time cardiac visualization. This work focuses on investigating the anatomical structure visualization of the human heart, which is fundamental to the cardiac visualization, medical training and diagnosis assistance. Several state-of-the-art cardiac visualization methods are integrated into the proposed system and a task specified visualization method is proposed. In addition, auxiliary tools are provided to generate user specified visualization results. The contributions of our work lie in two-fold: for doctors and medical staff, the system can provide task specified visualization with interactive visualization tools; for researchers, the proposed platform can serve as a baseline for comparing different rendering methods and can easily incorporate new rendering methods. Experimental results show that the proposed system can provide favorable cardiac visualization results in terms of both effectiveness and efficiency. PMID:27098778

  7. Modelling the cardiac transverse-axial tubular system

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Šimurda, J.; Christé, G.; Orchard, C.

    2008-01-01

    Roč. 96, - (2008), s. 226-246. ISSN 0079-6107 Institutional research plan: CEZ:AV0Z20760514 Keywords : cardiac cell * transverse-axial tubular system * quantitative modelling Subject RIV: BO - Biophysics Impact factor: 6.388, year: 2008

  8. PET and SPET tracers for mapping the cardiac nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Langer, Oliver; Halldin, Christer [Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institute, Karolinska Hospital, 17176 Stockholm (Sweden)

    2002-03-01

    The human cardiac nervous system consists of a sympathetic and a parasympathetic branch with (-)-norepinephrine and acetylcholine as the respective endogenous neurotransmitters. Dysfunction of the cardiac nervous system is implicated in various types of cardiac disease, such as heart failure, myocardial infarction and diabetic autonomic neuropathy. In vivo assessment of the distribution and function of cardiac sympathetic and parasympathetic neurones with positron emission tomography (PET) and single-photon emission tomography (SPET) can be achieved by means of a number of carbon-11-, fluorine-18-, bromine-76- and iodine-123-labelled tracer molecules. Available tracers for mapping sympathetic neurones can be divided into radiolabelled catecholamines, such as 6-[{sup 18}F]fluorodopamine, (-)-6-[{sup 18}F]fluoronorepinephrine and (-)-[{sup 11}C]epinephrine, and radiolabelled catecholamine analogues, such as [{sup 123}I]meta-iodobenzylguanidine, [{sup 11}C]meta-hydroxyephedrine, [{sup 18}F]fluorometaraminol, [{sup 11}C]phenylephrine and meta-[{sup 76}Br]bromobenzylguanidine. Resistance to metabolism by monoamine oxidase and catechol-O-methyl transferase simplifies the myocardial kinetics of the second group. Both groups of compounds are excellent agents for an overall assessment of sympathetic innervation. Biomathematical modelling of tracer kinetics is complicated by the complexity of the steps governing neuronal uptake, retention and release of these agents as well as by their high neuronal affinity, which leads to partial flow dependence of uptake. Mapping of cardiac parasympathetic neurones is limited by a low density and focal distribution pattern of these neurones in myocardium. Available tracers are derivatives of vesamicol, a molecule that binds to a receptor associated with the vesicular acetylcholine transporter. Compounds like (-)-[{sup 18}F]fluoroethoxybenzovesamicol display a high degree of non-specific binding in myocardium which restricts their utility

  9. PET and SPET tracers for mapping the cardiac nervous system

    International Nuclear Information System (INIS)

    The human cardiac nervous system consists of a sympathetic and a parasympathetic branch with (-)-norepinephrine and acetylcholine as the respective endogenous neurotransmitters. Dysfunction of the cardiac nervous system is implicated in various types of cardiac disease, such as heart failure, myocardial infarction and diabetic autonomic neuropathy. In vivo assessment of the distribution and function of cardiac sympathetic and parasympathetic neurones with positron emission tomography (PET) and single-photon emission tomography (SPET) can be achieved by means of a number of carbon-11-, fluorine-18-, bromine-76- and iodine-123-labelled tracer molecules. Available tracers for mapping sympathetic neurones can be divided into radiolabelled catecholamines, such as 6-[18F]fluorodopamine, (-)-6-[18F]fluoronorepinephrine and (-)-[11C]epinephrine, and radiolabelled catecholamine analogues, such as [123I]meta-iodobenzylguanidine, [11C]meta-hydroxyephedrine, [18F]fluorometaraminol, [11C]phenylephrine and meta-[76Br]bromobenzylguanidine. Resistance to metabolism by monoamine oxidase and catechol-O-methyl transferase simplifies the myocardial kinetics of the second group. Both groups of compounds are excellent agents for an overall assessment of sympathetic innervation. Biomathematical modelling of tracer kinetics is complicated by the complexity of the steps governing neuronal uptake, retention and release of these agents as well as by their high neuronal affinity, which leads to partial flow dependence of uptake. Mapping of cardiac parasympathetic neurones is limited by a low density and focal distribution pattern of these neurones in myocardium. Available tracers are derivatives of vesamicol, a molecule that binds to a receptor associated with the vesicular acetylcholine transporter. Compounds like (-)-[18F]fluoroethoxybenzovesamicol display a high degree of non-specific binding in myocardium which restricts their utility for cardiac neuronal imaging. (orig.)

  10. What nervous systems do: Early evolution, input-output, and the skin brain thesis

    OpenAIRE

    Keijzer, Fred; Duijn, Marc van; Lyon, Pamela

    2013-01-01

    Nervous systems are standardly interpreted as information processing input-output devices. They receive environmental information from their sensors as input, subsequently process or adjust this information, and use the result to control effectors, providing output. Through-conducting activity is here the key organizational feature of nervous systems. In this paper, we argue that this input-output interpretation is not the most fundamental feature of nervous system organization. Building on b...

  11. On reachability of dynamic systems. [input/output invariance despite on-off subsystem participation

    Science.gov (United States)

    Siljak, D. D.

    1977-01-01

    A large-scale dynamic system is considered as composed of a number of interconnected subsystems. Input and output reachability of the system is defined as a structural counterpart to controllability and observability. When the system is subject to structural perturbations due to on-off participation of the subsystems, conditions are provided for reachability to be connective, that is, to be invariant under the perturbations. The concept of input and output reachability leads naturally to formulations of input and output decentralized systems. It is shown that such systems are connectively reachable, which is an important structural property of 'large' and 'small' decentralized systems alike. Finally, a procedure is outlined to transform a centralized system into an input or output decentralized system with distinct inputs or outputs assigned to each subsystem separately.

  12. A Case of Femoral Arteriovenous Fistula Causing High-Output Cardiac Failure, Originally Misdiagnosed as Chronic Fatigue Syndrome

    Directory of Open Access Journals (Sweden)

    J. Porter

    2014-01-01

    Full Text Available Percutaneous arterial catheterisation is commonly undertaken for a range of diagnostic and interventional procedures. Iatrogenic femoral arteriovenous fistulas are an uncommon complication of these procedures. Most are asymptomatic and close spontaneously, but can rarely increase in size leading to the development of symptoms. We report a case of an iatrogenic femoral arteriovenous fistula, causing worsening congestive cardiac failure, in a 34-year-old marathon runner. This was originally diagnosed as chronic fatigue syndrome. Following clinical examination, duplex ultrasound, and CT angiography a significant arteriovenous fistula was confirmed. Elective open surgery was performed, leading to a dramatic and rapid improvement in symptoms. Femoral arteriovenous fistulas have the potential to cause significant haemodynamic effects and can present many years after the initial procedure. Conservative, endovascular, and open surgical management strategies are available.

  13. On the output-input stability property for multivariable nonlinear control systems

    OpenAIRE

    Liberzon, Daniel

    2002-01-01

    We study the recently introduced notion of output-input stability, which is a robust variant of the minimum-phase property for general smooth nonlinear control systems. The subject of this paper is developing the theory of output-input stability in the multi-input, multi-output setting. We show that output-input stability can be viewed as a combination of two system properties, one related to detectability and the other to left-invertibility. For systems affine in controls, we provide a neces...

  14. Locally derived system for cardiac operative risk evaluation

    Directory of Open Access Journals (Sweden)

    Mihajlović Bogoljub

    2014-01-01

    Full Text Available Introduction. During the last two decades, many authors have found that European Systems for Cardiac Operative Risk Evaluation (additive and logistic models overestimate the risk in cardiac surgery. The new European model has recently been introduced as an update to previous versions. The aim of the study was to investigate the significance of locally derived system for cardiac operative risk evaluation and to compare its predictive power with the existing European systems. Material and Methods. For developing a local risk prediction model, data from 2681 patients submitted to cardiac surgery at the Institute of Cardiovascular Diseases Vojvodina have thoroughly been collected. Logistic regression analysis was used to construct a local model for prediction of outcome. The evaluation of the local model and three European systems was performed by comparing the observed and expected hospital mortality. Results. The difference between the predicted and observed mortality regardless of the type of surgery was statistically insignificant for the additive European system (p=0.073 and the local model (p=0.134. The logistic European system overestimated the operative risk, while the new European model underestimated mortality. In coronary surgery, all models, except the logistic European system, performed well. In valvular surgery, the new European model and the local model underestimated mortality significantly, while the additive and logistic European models performed well. In combined surgery, the new European system significantly underestimated mortality (p=0.029, while the local model performed well (p=0.252. Conclusion. The locally derived model shows satisfactory results, with good calibration and discriminative power. The local model specifically outperforms all other European systems in terms of discriminatory power in combined surgery subset.

  15. Adaptive Output Tracking Control for Nonlinear Systems with Failed Actuators and Aircraft Flight System Applications

    OpenAIRE

    Chuanjing Hou; Lisheng Hu; Yingwei Zhang

    2015-01-01

    An adaptive failure compensation scheme using output feedback is proposed for a class of nonlinear systems with nonlinearities depending on the unmeasured states of systems. Adaptive high-gain K-filters are presented to suppress the nonlinearities while the proposed backstepping adaptive high-gain controller guarantees the stability of the closed-loop system and small tracking errors. Simulation results verify that the adaptive failure compensation scheme is effective.

  16. Digital stethoscope system: the feasibility of cardiac auscultation

    Science.gov (United States)

    Pariaszewska, Katarzyna; Młyńczak, Marcel; Niewiadomski, Wiktor; Cybulski, Gerard

    2013-10-01

    The application of the digital stethoscope system is a new tendency in methods of cardiac auscultation. Heart sounds, generated by the fluctuations of blood velocity and vibrations of muscle structure, are an important signal in the primary diagnosis of heart diseases. Since the XIXs century for physical examination an analog stethoscope was used, but the development of microelectronics enable the construction of digital stethoscopes which started modern phonocardiography. The typical hardware of the system could be divided into analog and digital parts, respectively. The first one consists of microphone and pre-amplifier. The second one contains a microcontroller with peripherals for data saving and transmission. Usually the specialized software is applied for the signal acquisition and digital signal processing (filtering, spectral analysis and others). This paper presents an overview of methods used in cardiac auscultation and expected developing path in the future. It also contains the description of our digital stethoscope system, which is planned to be used in poliphysiographical studies.

  17. PFC design via FRIT Approach for Adaptive Output Feedback Control of Discrete-time Systems

    Science.gov (United States)

    Mizumoto, Ikuro; Takagi, Taro; Fukui, Sota; Shah, Sirish L.

    This paper deals with a design problem of an adaptive output feedback control for discrete-time systems with a parallel feedforward compensator (PFC) which is designed for making the augmented controlled system ASPR. A PFC design scheme by a FRIT approach with only using an input/output experimental data set will be proposed for discrete-time systems in order to design an adaptive output feedback control system. Furthermore, the effectiveness of the proposed PFC design method will be confirmed through numerical simulations by designing adaptive control system with adaptive NN (Neural Network) for an uncertain discrete-time system.

  18. Engine Output Increase of Two-stroke Combustion with Exhaust System Optimization

    OpenAIRE

    Bigoš, Petar; Puškár, Michal

    2008-01-01

    In principle, an exhaust system influences the maximum output and characteristic of a two-stroke combustion engine. The first part of the contribution deals with the possibility of transformation in a maximum output and a range of exploitable speed values by means of the change of exhaust manifold length in exhaust pipe section. This knowledge covers an output curve variability of an engine operating speed range. The second part of this contribution deals with the combustion product's tempera...

  19. High Performance Input/Output Systems for High Performance Computing and Four-Dimensional Data Assimilation

    Science.gov (United States)

    Fox, Geoffrey C.; Ou, Chao-Wei

    1997-01-01

    The approach of this task was to apply leading parallel computing research to a number of existing techniques for assimilation, and extract parameters indicating where and how input/output limits computational performance. The following was used for detailed knowledge of the application problems: 1. Developing a parallel input/output system specifically for this application 2. Extracting the important input/output characteristics of data assimilation problems; and 3. Building these characteristics s parameters into our runtime library (Fortran D/High Performance Fortran) for parallel input/output support.

  20. Analysis of losses within SMES system for compensating output fluctuation of wind power farm

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. I.; Kim, J. H.; Le, T. D.; Lee, D. H.; Kim, H. M. [Jeju National University, Jeju (Korea, Republic of); Yoon, Y. S. [Dept. of Electrical Engineering, Shin Ansan University, Ansan (Korea, Republic of); Yoon, K. Y. [Dept. of lectrical and Electronic Engineering, Yonsei University, Seoul (Korea, Republic of)

    2014-12-15

    Output fluctuation which is generated in wind power farm can hinder stability of total power system. The electric energy storage (EES) reduces unstable output, and superconducting magnetic energy storage (SMES) of various EESs has the proper performance for output compensation of wind power farm since it charges and discharges large scale power quickly with high efficiency. However, because of the change of current within SMES, the electromagnetic losses occur in the process of output compensation. In this paper, the thermal effect of the losses that occur in SMES system while compensating in wind power farm is analyzed. The output analysis of wind power farm is processed by numerical analysis, and the losses of SMES system is analyzed by 3D finite element analysis (FEA) simulation tool.

  1. 21 CFR 862.1163 - Cardiac allograft gene expression profiling test system.

    Science.gov (United States)

    2010-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1163 Cardiac allograft gene expression profiling test system....

  2. Electromagnetic system for the management of the output power of the carbon dioxide laser

    Science.gov (United States)

    Martsinukov, S. A.; Kostrin, D. K.; Chernigovskiy, V. V.; Lisenkov, A. A.

    2016-07-01

    The methods to control the output power of the gas-discharge lasers are shown. An electromagnetic system for the management of the output power of the carbon dioxide laser is described. The results of calculation and modeling of the magnetic field in the working gap of the electromagnetic system are presented. Experimental studies on the distribution of magnetic induction in the electromagnetic system are carried out.

  3. State space and input-output linear systems

    CERN Document Server

    Delchamps, David F

    1988-01-01

    It is difficult for me to forget the mild sense of betrayal I felt some ten years ago when I discovered, with considerable dismay, that my two favorite books on linear system theory - Desoer's Notes for a Second Course on Linear Systems and Brockett's Finite Dimensional Linear Systems - were both out of print. Since that time, of course, linear system theory has undergone a transformation of the sort which always attends the maturation of a theory whose range of applicability is expanding in a fashion governed by technological developments and by the rate at which such advances become a part of engineering practice. The growth of the field has inspired the publication of some excellent books; the encyclopedic treatises by Kailath and Chen, in particular, come immediately to mind. Nonetheless, I was inspired to write this book primarily by my practical needs as a teacher and researcher in the field. For the past five years, I have taught a one semester first year gradu­ ate level linear system theory course i...

  4. Plasma volume expansion does not increase maximal cardiac output or VO2 max in lowlanders acclimatized to altitude

    DEFF Research Database (Denmark)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert Christopher;

    2004-01-01

    liter of 6% dextran 70 (BV = 6.32 +/- 0.34 liters). PV expansion had no effect on Qmax, maximal O2 consumption (VO2), and exercise capacity. Despite maximal systemic O2 transport being reduced 19% due to hemodilution after PV expansion, whole body VO2 was maintained by greater systemic O2 extraction (P...

  5. High Performance Input/Output for Parallel Computer Systems

    Science.gov (United States)

    Ligon, W. B.

    1996-01-01

    The goal of our project is to study the I/O characteristics of parallel applications used in Earth Science data processing systems such as Regional Data Centers (RDCs) or EOSDIS. Our approach is to study the runtime behavior of typical programs and the effect of key parameters of the I/O subsystem both under simulation and with direct experimentation on parallel systems. Our three year activity has focused on two items: developing a test bed that facilitates experimentation with parallel I/O, and studying representative programs from the Earth science data processing application domain. The Parallel Virtual File System (PVFS) has been developed for use on a number of platforms including the Tiger Parallel Architecture Workbench (TPAW) simulator, The Intel Paragon, a cluster of DEC Alpha workstations, and the Beowulf system (at CESDIS). PVFS provides considerable flexibility in configuring I/O in a UNIX- like environment. Access to key performance parameters facilitates experimentation. We have studied several key applications fiom levels 1,2 and 3 of the typical RDC processing scenario including instrument calibration and navigation, image classification, and numerical modeling codes. We have also considered large-scale scientific database codes used to organize image data.

  6. Preliminary Test for Nonlinear Input Output Relations in SISO Systems

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2000-01-01

    This paper discusses and develops preliminary statistical tests for detecting nonlinearities in the deterministic part of SISO systems with noise. The most referenced method is unreliable for common noise processes as e.g.\\ colored. Therefore two new methods based on superposition and sinus input...

  7. Cardiac manifestation's history in the systemic lupus erythematosus

    International Nuclear Information System (INIS)

    In this paper it is broadly and in depth reviewed the cardiac manifestation's history of systemic lupus erythematosus (SLE), since an historical analysis of clinical manifestations both in pre and post corticosteroids period. The way how the heart and the cardiovascular system's functions have been studied by clinical and semiological views are showed, through clinical manifestations such as myocarditis pericarditis, endocarditis, rhythm alterations, etc, and the evolution of laboratory methods used to its study as well as immunologic prognostic markers and risk factors for coronary disease in SLE

  8. Decentralised memory static output feedback control for the nonlinear time-delay similar interconnected systems

    Science.gov (United States)

    Ma, Yuechao; Jin, Shujie; Gu, Nannan

    2016-07-01

    In this paper, the problem of decentralised memory static output feedback control for a class of nonlinear time-delayed interconnected systems with similar structure is investigated, where both the linear and nonlinear state vectors involve time delay. The contributions of the paper include the following: (1) a new similar structure is presented via memory static output feedback; (2) by exploiting the structure of interconnected systems, the new integral inequalities, constrained Lyapunov equations and LMI method, the decentralised memory static output derivative feedback controllers with similar structure are designed, which is dependent of time delays, to stabilise the interconnected systems uniformly asymptotically; and (3) the stability domain is estimated. The conservatism of the results obtained is reduced by full using the system output information. Finally, the numerical examples are given to demonstrate the effectiveness of the results obtained in this paper.

  9. Synthesis of dissipative output feedback controllers. Application to mechanical systems

    Energy Technology Data Exchange (ETDEWEB)

    Johannessen, Erling Aarsand

    1997-12-31

    This thesis presents new results on the synthesis of linear controllers with passivity, or more general, dissipativity properties. These methods may be applied to obtain more accurate control over mechanical systems and in the control of chemical processes that involve dissipative subsystems. The thesis presents two different approaches for synthesis of dissipative controllers: (1) A method that exploits the Riccati equation solution to the state space formulation of the H{sub {infinity}} control problem is investigated, illustrated by synthesising a controller for damping of flexible modes in a beam. (2) A more general method for dissipative control synthesis is developed that retains the well-known techniques of loop-shaping and frequency weighting in H{sub {infinity}}. A method is also presented for controller synthesis directly from frequency response data. 82 refs., 34 figs., 3 tabs.

  10. Use of a capillary input function with cardiac output for the estimation of lesion pharmacokinetic parameters: preliminary results on a breast cancer patient

    Science.gov (United States)

    Di Giovanni, P.; Ahearn, T. S.; Semple, S. I.; Azlan, C. A.; Lloyd, W. K. C.; Gilbert, F. J.; Redpath, T. W.

    2011-03-01

    The objective of this work was to propose and demonstrate a novel technique for the assessment of tumour pharmacokinetic parameters together with a regionally estimated vascular input function. A breast cancer patient T2*-weighted dynamic contrast enhanced MRI (DCE-MRI) dataset acquired at high temporal resolution during the first-pass bolus perfusion was used for testing the technique. Extraction of the lesion volume transfer constant Ktrans together with the intravascular plasma volume fraction vp was achieved by optimizing a capillary input function with a measure of cardiac output using the principle of intravascular indicator dilution theory. For a region of interest drawn within the breast lesion a vp of 0.16 and a Ktrans of 0.70 min-1 were estimated. Despite the value of vp being higher than expected, estimated Ktrans was in accordance with the literature values. In conclusion, the technique proposed here, has the main advantage of allowing the estimation of breast tumour pharmacokinetic parameters from first-pass perfusion T2*-weighted DCE-MRI data without the need of measuring an arterial input function. The technique may also have applicability to T1-weighted DCE-MRI data.

  11. State Space Consistency and Differentiability Conditions for a Class of Causal Dynamical Input-Output Systems

    CERN Document Server

    Serakos, Demetrios

    2010-01-01

    A causal input-output system may be described by a function space for inputs, a function space for outputs, and a causal operator mapping the input space into the output space. A particular representation of the state of such a system at any instant has been defined as an operator from the space of possible future inputs to that of future outputs. This representation is called the natural state. The purpose of this report is to investigate additional properties of the natural state in two areas. The first area has to do with the possibility of determining the input-output system from its natural state set. A counterexample where this is not possible is given. Sufficient conditions for identifying the system from its natural state set are given. The results in this area are mostly for time-invariant systems. There are also some preliminary observations on reachability. The second area deals with differentiability properties involving the natural state inherited from the input-output system, including different...

  12. Tracking Controller for Intrinsic Output Saturated Systems in Presence of Amplitude and Rate Input Saturations

    DEFF Research Database (Denmark)

    Chater, E.; Giri, F.; Guerrero, Josep M.;

    2014-01-01

    We consider the problem of controlling plants that are subject to multiple saturation constraints. Especially, we are interested in linear systems whose input is subject to amplitude and rate constraints of saturation type. Furthermore, the considered systems output is also subject to an intrinsic......-loop control system is analyzed using input-output stability tools. Thus, conditions guaranteeing l2-tracking performances are formally defined. Interestingly, the proposed controller is shown to ensure perfect output-reference tracking in presence of varying with l2-vanishing rate inputs. On the other hand......, in the case of arbitrary inputs, the proposed controller guarantees that the less changing the inputs are the better the output-reference tracking....

  13. Data acquisition in a wireless diabetic and cardiac monitoring system.

    Science.gov (United States)

    Harvey, Paul; Woodward, Bryan; Datta, Sekharjit; Mulvaney, David

    2011-01-01

    A telemedicine system is described for monitoring the vital signs and general health indicators of patients with cardiac and diabetic conditions. Telemetry from wireless sensors and readings from other instruments are combined into a comprehensive patient health dataset. The data can be stored, accessed and displayed using mobile Internet communications with a server. The paper concentrates on the data acquisition process, using an alternative sensor network protocol to Bluetooth and manual data entry into a smartphone application and HTML5 web browser. PMID:22255009

  14. An optical system to transform the output beam of a quantum cascade laser to be uniform

    Science.gov (United States)

    Jacobson, Jordan M.

    Quantum cascade lasers (QCLs) are a candidate for calibration sources in space-based remote sensing applications. However, the output beam from a QCL has some characteris- tics that are undesirable in a calibration source. The output beam from a QCL is polarized, both temporally and spatially coherent, and has a non-uniform bivariate Gaussian prole. These characteristics need to be mitigated before QCLs can be used as calibration sources. This study presents the design and implementation of an optical system that manipulates the output beam from a QCL so that it is spatially and angularly uniform with reduced coherence and polarization. (85 pages).

  15. Decentralized H∞ Control for Uncertain Interconnected Systems of Neutral Type via Dynamic Output Feedback

    Directory of Open Access Journals (Sweden)

    Heli Hu

    2014-01-01

    Full Text Available The design of the dynamic output feedback H∞ control for uncertain interconnected systems of neutral type is investigated. In the framework of Lyapunov stability theory, a mathematical technique dealing with the nonlinearity on certain matrix variables is developed to obtain the solvability conditions for the anticipated controller. Based on the corresponding LMIs, the anticipated gains for dynamic output feedback can be achieved by solving some algebraic equations. Also, the norm of the transfer function from the disturbance input to the controlled output is less than the given index. A numerical example and the simulation results are given to show the effectiveness of the proposed method.

  16. Optimal Tracking Control of Unknown Discrete-Time Linear Systems Using Input-Output Measured Data.

    Science.gov (United States)

    Kiumarsi, Bahare; Lewis, Frank L; Naghibi-Sistani, Mohammad-Bagher; Karimpour, Ali

    2015-12-01

    In this paper, an output-feedback solution to the infinite-horizon linear quadratic tracking (LQT) problem for unknown discrete-time systems is proposed. An augmented system composed of the system dynamics and the reference trajectory dynamics is constructed. The state of the augmented system is constructed from a limited number of measurements of the past input, output, and reference trajectory in the history of the augmented system. A novel Bellman equation is developed that evaluates the value function related to a fixed policy by using only the input, output, and reference trajectory data from the augmented system. By using approximate dynamic programming, a class of reinforcement learning methods, the LQT problem is solved online without requiring knowledge of the augmented system dynamics only by measuring the input, output, and reference trajectory from the augmented system. We develop both policy iteration (PI) and value iteration (VI) algorithms that converge to an optimal controller that require only measuring the input, output, and reference trajectory data. The convergence of the proposed PI and VI algorithms is shown. A simulation example is used to verify the effectiveness of the proposed control scheme. PMID:25576591

  17. Cross-correlation of output fluctuation and system-balancing cost in photovoltaic integration

    Directory of Open Access Journals (Sweden)

    Yuichi Ikeda

    2014-10-01

    Full Text Available The authors analysed the cross-correlation of photovoltaic (PV output fluctuation for the actual PV output time series data in both the Tokyo area and the whole of Japan using the principal component analysis with the random matrix theory. Based on the obtained cross-correlation coefficients, the forecast error for PV output was estimated with/without considering the cross-correlations. Then the operation schedule of thermal plants is calculated to integrate PV output using the proposed unit commitment model with the estimated forecast error. The system-balancing cost of PV system was also estimated with or without demand response. Finally, validity of the concept of ‘local production for local consumption of renewable energy’ and alternative policy implications were discussed.

  18. Sizing of Energy Storage Systems for Output Smoothing of Renewable Energy Systems

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Renewable energy sources (RESs), such as photovoltaic (PV) and wind power generation, have the characteristics of random fluctuation and intermittence. The output of RESs should be smoothed to inhibit the adverse effects of RESs fluctuations on the power grid. The energy storage system (ESS) is playing a more and more important role in the application of RESs due to its discharge/charge characteristic. Therefore, the optimal planning and design of ESS is of vital importance because of the expensive cost of ESS.

  19. Decision Technique of Solar Radiation Prediction Applying Recurrent Neural Network for Short-Term Ahead Power Output of Photovoltaic System

    OpenAIRE

    Atsushi Yona; Tomonobu Senjyu; Toshihisa Funabashi; Paras Mandal; Chul-Hwan Kim

    2013-01-01

    In recent years, introduction of a renewable energy source such as solar energy is expected. However, solar radiation is not constant and power output of photovoltaic (PV) system is influenced by weather conditions. It is difficult for getting to know accurate power output of PV system. In order to forecast the power output of PV system as accurate as possible, this paper proposes a decision technique of forecasting model for short-term-ahead power output of PV system based on solar radiatio...

  20. Bifurcation suppression of nonlinear systems via dynamic output feedback and its applications to rotating stall control

    Institute of Scientific and Technical Information of China (English)

    Pengnian CHEN; Huashu QIN; Shengwei MEI

    2005-01-01

    This paper deals with the problems of bifurcation suppression and bifurcation suppression with stability of nonlinear systems. Necessary conditions and sufficient conditions for bifurcation suppression via dynamic output feedback are presented;Sufficient conditions for bifurcation suppression with stability via dynamic output feedback are obtained. As an application, a dynamic compensator, which guarantees that the bifurcation point of rotating stall in axial flow compressors is stably suppressed, is constructed.

  1. Robust Output Feedback Control for a Class of Nonlinear Systems with Input Unmodeled Dynamics

    Institute of Scientific and Technical Information of China (English)

    Ming-Zhe Hou; Ai-Guo Wu; Guang-Ren Dua

    2008-01-01

    The robust global stabilization problem of a class of uncertain nonlinear systems with input unmodeled dynamics is considered using output feedback, where the uncertain nonlinear terms satisfy a far more relaxed condition than the existing triangular- type condition. Under the assumption that the input unmodeled dynamics is minimum-phase and of relative degree zero, a dynamic output compensator is explicitly constructed based on the nonseparation principle. An example illustrates the usefulness of the proposed method.

  2. GENERAL RELIABILITY THEORY STUDY ON SEMI-FLEXIBLE OUTPUT TYPE AND REPAIRABLE PRODUCTION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    马云东; 高宏伟

    1996-01-01

    This paper puts forward the conceptions of semi-flexible units and semi-flexible system, and builds up the theory of semi-flexible output type and repairable production system general reliability analysis and general reliability design, which discusses the reliability problems of semi-flexible units and semi-flexible system from three aspects of time, task and capacity.

  3. System identification from closed-loop data with known output feedback dynamics

    Science.gov (United States)

    Phan, Minh; Juang, Jer-Nan; Horta, Lucas G.; Longman, Richard W.

    1992-01-01

    This paper presents a procedure to identify the open loop systems when it is operating under closed loop conditions. First, closed loop excitation data are used to compute the system open loop and closed loop Markov parameters. The Markov parameters, which are the pulse response samples, are then used to compute a state space representation of the open loop system. Two closed loop configurations are considered in this paper. The closed loop system can have either a linear output feedback controller or a dynamic output feedback controller. Numerical examples are provided to illustrate the proposed closed loop identification method.

  4. Variable structure control for MRAC systems with perturbations in input and output channels

    Institute of Scientific and Technical Information of China (English)

    武玉强[1; 余星火[2; 冯纯伯[3

    2000-01-01

    A design scheme of variable structure model reference control systems using only input and output measurements is presented for the systems with unmodeled dynamics and disturbances in input and output channels. The modeled part of the systems has relative degree greater than one and unknown upper bound of degree. By introducing some auxiliary signals and normalized signals with memory functions and appropriate choice of controller parameters, the developed variable structure controller guarantees the global stability of the closed-loop system and the arbitrarily small tracking error.

  5. Output-synchronization for the Different-order Uncertain Chaotic Systems via Fuzzy Sliding Control

    Directory of Open Access Journals (Sweden)

    Ning Li

    2015-07-01

    Full Text Available In this study, the synchronization of the outputs for the uncertain chaotic systems with different-orders is presented. An adaptive fuzzy system has been used to approximate the uncertain nonlinear terms. The adaptive fuzzy control strategy is estimated to guarantee output-synchronization of the master-slave chaotic systems based on sliding control theorem. By using a dynamic compensator, the performance of the closed-loop systems in sliding mode is improved. The proposed controller can ensure synchronous error converges to zero. Simulation results are provided to illustrate the effectiveness of the proposed method

  6. One output function: a misconception of students studying digital systems - a case study

    Science.gov (United States)

    Trotskovsky, E.; Sabag, N.

    2015-05-01

    Background:Learning processes are usually characterized by students' misunderstandings and misconceptions. Engineering educators intend to help their students overcome their misconceptions and achieve correct understanding of the concept. This paper describes a misconception in digital systems held by many students who believe that combinational logic circuits should have only one output. Purpose:The current study aims to investigate the roots of the misconception about one-output function and the pedagogical methods that can help students overcome the misconception. Sample:Three hundred and eighty-one students in the Departments of Electrical and Electronics and Mechanical Engineering at an academic engineering college, who learned the same topics of a digital combinational system, participated in the research. Design and method:In the initial research stage, students were taught according to traditional method - first to design a one-output combinational logic system, and then to implement a system with a number of output functions. In the main stage, an experimental group was taught using a new method whereby they were shown how to implement a system with several output functions, prior to learning about one-output systems. A control group was taught using the traditional method. In the replication stage (the third stage), an experimental group was taught using the new method. A mixed research methodology was used to examine the results of the new learning method. Results:Quantitative research showed that the new teaching approach resulted in a statistically significant decrease in student errors, and qualitative research revealed students' erroneous thinking patterns. Conclusions:It can be assumed that the traditional teaching method generates an incorrect mental model of the one-output function among students. The new pedagogical approach prevented the creation of an erroneous mental model and helped students develop the correct conceptual understanding.

  7. Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

    International Nuclear Information System (INIS)

    Highlights: ► Propofol, as a model anesthetic drug, induced whole body insulin resistance. ► Propofol anesthesia decreased glucose infusion rate to maintain euglycemia. ► Propofol decreased insulin-mediated glucose uptake in skeletal and cardiac muscles. ► Propofol increased hepatic glucose output confirming hepatic insulin resistance. -- Abstract: Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [3H]glucose and 2-deoxy[14C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats

  8. Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Yoshikazu; Fukushima, Yuji; Kaneki, Masao [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States); Martyn, J.A. Jeevendra, E-mail: jmartyn@partners.org [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States)

    2013-02-01

    Highlights: ► Propofol, as a model anesthetic drug, induced whole body insulin resistance. ► Propofol anesthesia decreased glucose infusion rate to maintain euglycemia. ► Propofol decreased insulin-mediated glucose uptake in skeletal and cardiac muscles. ► Propofol increased hepatic glucose output confirming hepatic insulin resistance. -- Abstract: Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [{sup 3}H]glucose and 2-deoxy[{sup 14}C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats.

  9. Prescribed Performance Fuzzy Adaptive Output-Feedback Control for Nonlinear Stochastic Systems

    Directory of Open Access Journals (Sweden)

    Lili Zhang

    2014-01-01

    Full Text Available A prescribed performance fuzzy adaptive output-feedback control approach is proposed for a class of single-input and single-output nonlinear stochastic systems with unmeasured states. Fuzzy logic systems are used to identify the unknown nonlinear system, and a fuzzy state observer is designed for estimating the unmeasured states. Based on the backstepping recursive design technique and the predefined performance technique, a new fuzzy adaptive output-feedback control method is developed. It is shown that all the signals of the resulting closed-loop system are bounded in probability and the tracking error remains an adjustable neighborhood of the origin with the prescribed performance bounds. A simulation example is provided to show the effectiveness of the proposed approach.

  10. Adaptive Neural Network Output Feedback Tracking Control for a Class of Complicated Agricultural Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Hui Hu

    2015-07-01

    Full Text Available The study presents an adaptive neural network output feedback tracking control scheme for a class of complicated agricultural mechanical systems. The scheme includes a dynamic gain observer to estimate the un-measurable states of the system. The main advantages of the authors scheme are that by introducing non-separation principle design neural network controller and the observer gain are simultaneously tuned according to output tracking error, the semi-globally ultimately bounded of output tracking error and all the states in the closed-loop system can be achieved by Lyapunov approach. With the universal approximation property of NN and the simultaneous parametrisation, no Lipschitz assumption and SPR condition are employed which makes the system construct simple. Finally the simulation results are presented to demonstrate the efficiency of the control scheme.

  11. Bidirectional output stage matrix converter applied to a distributed generation system

    Science.gov (United States)

    Ortega, Manuel; Jurado, Francisco; Roa, Juan P.

    2012-08-01

    In this article a new bidirectional output stage ultra-sparse matrix converter (BOSUMC) is presented. This converter is designed for connecting a hybrid electrical system to a distributed generation network. The proposed converter comprises an input stage and an output stage with six bidirectional switches in such a way that both the input and output stages are linked with a DC link, which can be coupled to an electrolyser and a fuel cell. The converter allows the current to flow in both ways in its output stage, and if there is an excess of energy in the network, it can be transformed into electric direct current and later into hydrogen for its exploitation. For verifying the control algorithm of the BOSUMC, a laboratory prototype has been prepared using among other elements a Spectrum Digital eZdsp™ TMS320F2812 card.

  12. A Novel Minimum Output Variance Estimator for Carrier Frequency Offset in OFDM Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In orthogonal frequency-division multiplexing (OFDM) systems, the carrier frequency offset (CFO)destroys the orthogonality among subcarriers which degrades system performance. Various CFO estimation methods have been developed to compensate for the CFO at the receiver. This paper describes a novel minimum output variance method for OFDM systems with CFO in additive white Gaussian noise channels.This method utilizes the phase and the amplitude of the received signal and reduces the mean square error of the CFO by about 3 dB compared with the original minimum output variance method.

  13. Laguerre-Volterra model and architecture for MIMO system identification and output prediction.

    Science.gov (United States)

    Li, Will X Y; Xin, Yao; Chan, Rosa H M; Song, Dong; Berger, Theodore W; Cheung, Ray C C

    2014-01-01

    A generalized mathematical model is proposed for behaviors prediction of biological causal systems with multiple inputs and multiple outputs (MIMO). The system properties are represented by a set of model parameters, which can be derived with random input stimuli probing it. The system calculates predicted outputs based on the estimated parameters and its novel inputs. An efficient hardware architecture is established for this mathematical model and its circuitry has been implemented using the field-programmable gate arrays (FPGAs). This architecture is scalable and its functionality has been validated by using experimental data gathered from real-world measurement. PMID:25571001

  14. Explicit least squares system parameter identification for exact differential input/output models

    Science.gov (United States)

    Pearson, A. E.

    1993-01-01

    The equation error for a class of systems modeled by input/output differential operator equations has the potential to be integrated exactly, given the input/output data on a finite time interval, thereby opening up the possibility of using an explicit least squares estimation technique for system parameter identification. The paper delineates the class of models for which this is possible and shows how the explicit least squares cost function can be obtained in a way that obviates dealing with unknown initial and boundary conditions. The approach is illustrated by two examples: a second order chemical kinetics model and a third order system of Lorenz equations.

  15. AN ALGORITHM FOR DESIGN OF A PID CONTROLLER FOR MULTIVARIABLE SYSTEM USING OUTPUT FEEDBACK

    Directory of Open Access Journals (Sweden)

    Suma H

    2010-12-01

    Full Text Available This paper deals with the design of a proportional-plus-integral-plus-derivative (PID controller for linear multivariable systems using an output feedback control law. Controller is designed as an equivalent proportionalplus- derivative controller for the augmented system formed due to the integral action. The design equations areformulated in terms of coefficient matrix of the transfer function vector of the equivalent single input (or single output system. The computation of coefficient matrix of a transfer function vector gives a simple and direct procedure for pole assignment. The design procedure does not require cyclicity as an initial condition. The controller design is illustrated with a numerical example.

  16. Robust output feedback H-infinity control and filtering for uncertain linear systems

    CERN Document Server

    Chang, Xiao-Heng

    2014-01-01

    "Robust Output Feedback H-infinity Control and Filtering for Uncertain Linear Systems" discusses new and meaningful findings on robust output feedback H-infinity control and filtering for uncertain linear systems, presenting a number of useful and less conservative design results based on the linear matrix inequality (LMI) technique. Though primarily intended for graduate students in control and filtering, the book can also serve as a valuable reference work for researchers wishing to explore the area of robust H-infinity control and filtering of uncertain systems. Dr. Xiao-Heng Chang is a Professor at the College of Engineering, Bohai University, China.

  17. Morphological observations of tumors in cardiac conduction system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Tumors of the cardiac conduction system (CCS) have rarely been reported. The CCS from 198 cardiac-related deaths (GroupⅠ),and 838 deaths from non-cardiovascular diseases or trauma (Group Ⅱ ), were studied. Sampling was done of the sinoatrial node (SAN)and atrio-ventricular node (AVN) along their long axis of each node as a single block and the His bundle (HB) perpendicular to its long axis in 2-4 blocks. Five-micron serial sections were made; tissue slices were taken intermittently, every 20th from the SAN, every 10th from the AVN, and every 30th from the HB and bundle branches (BB), by continuous slices three times. Tumors in the CCS were found in 12 cases (1.155 %), where 10 (0.965%) were primary tumors, and 2 (0.193%) were metastatic tumors. The primary tumors included 4 fibromata compressing the HB (0.386 %), 4 hemangiomata (0.386%), 1 AVN tumor (0.097 %), and 1 rhabdomyoma (0.097 %). In 8 of the 10 cases, the tumors were located in the AVN or HB. The metastatic tumors originated from lymphocytic leukemia and malignant lymphoma (histiocytic type) in lung, and were all found in the SAN. Of the 12 cases, 2 were from the group Ⅰ. Tumors in the CCS are the smallest tumors in different parts of the body, which can cause sudden death.

  18. Brain renin angiotensin system in cardiac hypertrophy and failure

    Directory of Open Access Journals (Sweden)

    MichaelBader

    2012-01-01

    Full Text Available Brain renin-angiotensin system (RAS is significantly involved in the roles of the endocrine RAS in cardiovascular regulation. Our studies indicate that the brain RAS participates in the development of cardiac hypertrophy and fibrosis through sympathetic activation. Inhibition of sympathetic hyperactivity after myocardial infarction through suppression of the brain RAS appears beneficial. The brain RAS is involved in the modulation of circadian rhythms of arterial pressure, contributing to nondipping hypertension. We conclude that the brain RAS in pathophysiological states interacts synergistically with the chronically overactive RAS through a positive biofeedback in order to maintain a state of alert diseased conditions, such as cardiac hypertrophy and failure. Therefore, targeting brain RAS with drugs such as angiotensin converting inhibitors or receptor blockers having increased brain penetrability could be of advantage. These RAS-targeting drugs are first-line therapy for all heart failure patients. Since the RAS has both endocrine and local tissue components, RAS drugs are being developed to attain increased tissue penetrability and volume of distribution and consequently an efficient inhibition of both RAS components.

  19. Robust Pole Assignment of Digital Control System with Output Multirate Sampled

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Multirate digital control system is a periodically time-variant (PTV)system in its essence. It has many “super capability”, such as obtaining arbitrarily-large gain-margin,simultaneous stabilization, strong stabilization, decentralized control, etc. Utilizing freedom aroused from the multirate sampling of system output, this paper assigns poles of the closedloop system robustly, and so improves the resistance of the system to perturbation.

  20. Feedback passivity of nonlinear discrete-time systems with direct input-output link

    OpenAIRE

    Navarro López, Eva María; Fossas Colet, Enric

    2004-01-01

    This paper is devoted to the study of the feedback passivity property in nonlinear discrete-time systems. The relative degree and zero dynamics of the non-passive system are related to the feedback passivity of the system. Two main results are presented. First, some relative degreerelated properties of passive systems in general form are stated. Second, sufficient conditions in order to render a multiple-input multiple-output (MIMO) system passive by means of a static state feedback control l...

  1. Modal Identification of Output-only Systems Using Frequency Domain Decomposition

    DEFF Research Database (Denmark)

    Brincker, Rune; Zhang, L.M.; Andersen, Palle

    2001-01-01

     In this paper a new frequency domain technique is introduced for the modal identification of output-only systems, i.e. in the case where the modal parameters must be estimated without knowing the input exciting the system. By its user friendliness the technique is closely related to the classica...

  2. Modeling and control of the output current of a Reformed Methanol Fuel Cell system

    DEFF Research Database (Denmark)

    Justesen, Kristian Kjær; Andreasen, Søren Juhl; Pasupathi, Sivakumar;

    2015-01-01

    In this work, a dynamic Matlab SIMULINK model of the relationship between the fuel cell current set point of a Reformed Methanol Fuel Cell system and the output current of the system is developed. The model contains an estimated fuel cell model, based on a polarization curve and assumed first order...

  3. Dialog system for automatic data input/output and processing with two BESM-6 computers

    International Nuclear Information System (INIS)

    This paper presents a system for conducting experiments with fully automatic processing of data from multichannel recorders in the dialog mode. The system acquires data at a rate of 2.5 . 103 readings/sec, processes in real time, and outputs digital and graphical material in a multitasking environment

  4. On the input-output properties of linear time-invariant systems.

    Science.gov (United States)

    Desoer, C. A.; Lam, F. L.

    1972-01-01

    Recently improved sufficient conditions for the Lp stability of multiple-input multiple-output linear time-invariant feedback systems are given. The continuous-time case is done in detail; the discrete-time case is outlined. Unstable open-loop systems with singular residue matrices are allowed.

  5. Output feedback stabilization for time-delay nonlinear interconnected systems using neural networks.

    Science.gov (United States)

    Hua, C; Guan, X

    2008-04-01

    In this paper, dynamic output feedback control problem is investigated for a class of nonlinear interconnected systems with time delays. Decentralized observer independent of the time delays is first designed. Then, we employ the bounds information of uncertain interconnections to construct the decentralized output feedback controller via backstepping design method. Based on Lyapunov stability theory, we show that the designed controller can render the closed-loop system asymptotically stable with the help of the changing supplying function idea. Furthermore, the corresponding decentralized control problem is considered under the case that the bounds of uncertain interconnections are not precisely known. By employing the neural network approximation theory, we construct the neural network output feedback controller with corresponding adaptive law. The resulting closed-loop system is stable in the sense of semiglobal boundedness. The observers and controllers constructed in this paper are independent of the time delays. Finally, simulations are done to verify the effectiveness of the theoretic results obtained. PMID:18390312

  6. Adaptive Output-Feedback Neural Control of Switched Uncertain Nonlinear Systems With Average Dwell Time.

    Science.gov (United States)

    Long, Lijun; Zhao, Jun

    2015-07-01

    This paper investigates the problem of adaptive neural tracking control via output-feedback for a class of switched uncertain nonlinear systems without the measurements of the system states. The unknown control signals are approximated directly by neural networks. A novel adaptive neural control technique for the problem studied is set up by exploiting the average dwell time method and backstepping. A switched filter and different update laws are designed to reduce the conservativeness caused by adoption of a common observer and a common update law for all subsystems. The proposed controllers of subsystems guarantee that all closed-loop signals remain bounded under a class of switching signals with average dwell time, while the output tracking error converges to a small neighborhood of the origin. As an application of the proposed design method, adaptive output feedback neural tracking controllers for a mass-spring-damper system are constructed. PMID:25122844

  7. Input-output description of linear systems with multiple time-scales

    Science.gov (United States)

    Madriz, R. S.; Sastry, S. S.

    1984-01-01

    It is pointed out that the study of systems evolving at multiple time-scales is simplified by studying reduced-order models of these systems valid at specific time-scales. The present investigation is concerned with an extension of results on the time-scale decomposition of autonomous systems to that of input-output systems. The results are employed to study conditions under which positive realness of a transfer function is preserved under singular perturbation. Attention is given to the perturbation theory for linear operators, the multiple time-scale structure of autonomous linear systems, the input-output description of two time-scale linear systems, the positive realness of two time-scale systems, and multiple time-scale linear systems.

  8. Cardiac imaging systems and methods employing computerized tomographic scanning

    International Nuclear Information System (INIS)

    A novel method for obtaining cardiac images with X-rays is described. The problem of blurring of the image due to motion of the heart and its associated blood vessels is overcome by monitoring the cardiac cycle to produce a repeating pulse signal indicative of the same selectable phase; a pacemaker may be used to stabilize the cardiac period. Conventional CT scanning may then be performed and only the information recorded in coincidence with certain phases of the cardiac cycle is compounded to produce cardiac images which are free from blurring. Alternatively, the X-ray tube may be gated on and off by the pulse derived from the cardiac cycle in order to reduce X-ray dosage. (U.K.)

  9. Autonomic Dysfunction Predicts Early Cardiac Affection in Patients with Systemic Sclerosis

    OpenAIRE

    Othman, Khaled M.; Naglaa Youssef Assaf; Hanan Mohamed Farouk; Iman M. Aly Hassan

    2010-01-01

    Objective: To detect the early preclinical alterations in cardiac autonomic control as well as altered cardiac function in systemic sclerosis (SSc) patients and their relevance to the clinical features of the disease using noninvasive methods. Methods: 30 SSc patients and 15 healthy controls matched for age and sex underwent clinical examination, serological analysis, and echocardiographic assessment including Doppler flow imaging to evaluate cardiac function, and 24-hour Holter monitoring an...

  10. Linearized Controller Design for the Output Probability Density Functions of Non-Gaussian Stochastic Systems

    Institute of Scientific and Technical Information of China (English)

    Pousga Kabore; Husam Baki; Hong Yue; Hong Wang

    2005-01-01

    This paper presents a linearized approach for the controller design of the shape of output probability density functions for general stochastic systems. A square root approximation to an output probability density function is realized by a set of B-spline functions. This generally produces a nonlinear state space model for the weights of the B-spline approximation. A linearized model is therefore obtained and embedded into a performance function that measures the tracking error of the output probability density function with respect to a given distribution. By using this performance function as a Lyapunov function for the closed loop system, a feedback control input has been obtained which guarantees closed loop stability and realizes perfect tracking. The algorithm described in this paper has been tested on a simulated example and desired results have been achieved.

  11. Cardiac arrest during gamete release in chum salmon regulated by the parasympathetic nerve system.

    Directory of Open Access Journals (Sweden)

    Yuya Makiguchi

    Full Text Available Cardiac arrest caused by startling stimuli, such as visual and vibration stimuli, has been reported in some animals and could be considered as an extraordinary case of bradycardia and defined as reversible missed heart beats. Variability of the heart rate is established as a balance between an autonomic system, namely cholinergic vagus inhibition, and excitatory adrenergic stimulation of neural and hormonal action in teleost. However, the cardiac arrest and its regulating nervous mechanism remain poorly understood. We show, by using electrocardiogram (ECG data loggers, that cardiac arrest occurs in chum salmon (Oncorhynchus keta at the moment of gamete release for 7.39+/-1.61 s in females and for 5.20+/-0.97 s in males. The increase in heart rate during spawning behavior relative to the background rate during the resting period suggests that cardiac arrest is a characteristic physiological phenomenon of the extraordinarily high heart rate during spawning behavior. The ECG morphological analysis showed a peaked and tall T-wave adjacent to the cardiac arrest, indicating an increase in potassium permeability in cardiac muscle cells, which would function to retard the cardiac action potential. Pharmacological studies showed that the cardiac arrest was abolished by injection of atropine, a muscarinic receptor antagonist, revealing that the cardiac arrest is a reflex response of the parasympathetic nerve system, although injection of sotalol, a beta-adrenergic antagonist, did not affect the cardiac arrest. We conclude that cardiac arrest during gamete release in spawning release in spawning chum salmon is a physiological reflex response controlled by the parasympathetic nervous system. This cardiac arrest represents a response to the gaping behavior that occurs at the moment of gamete release.

  12. Experimental and theoretical analysis of cell module output performance for a thermophotovoltaic system

    International Nuclear Information System (INIS)

    Highlights: • An accurate theoretical model for thermophotovoltaic system is constructed. • Parallel connected module is superior if radiator temperature is uneven. • Series connected module is superior if cell temperature is uneven. • Short circuit current of series module rises when the shunt resistance decreases. • Fill factor is not always accurate to evaluate the module performance. - Abstract: An experimental thermophotovoltaic (TPV) system with a cylindrical-geometry radiator was established to test the output performances of modules under different conditions. The results demonstrate that the output performance of a cell module decreases when the combustion power increases because of the uneven temperature of the radiator or cells. On this basis, a theoretical model for a TPV system was constructed to compare the performance under different conditions of the series-connected (SC) module and the parallel-connected (PC) module, and was verified by the experimental results. The influences of the temperature gradient of the radiator or the cell module, and the series and shunt resistance of the TPV cell on the module performance were analyzed in detail. The results demonstrate that the PC module can effectively reduce the mismatch loss of output power caused by the uneven radiator temperature. The PC module, for instance, has a maximum output power of 2.54 times higher than that of the SC module when the radiator temperature difference is 500 K. However, the output performance of the module connected in series is superior to the PC module while the cell temperature is non-uniform. The output power of the SC module is 9.93% higher than that of the PC module at the cell temperature difference of 125 K. The short circuit current of the SC module is sensitive to the series and shunt resistance if the radiator temperature distribution is non-uniform. As the shunt resistance falls from ∞ to 0.5 Ω, the current varies from 1.757 A to 4.488 A when the

  13. Determining the Frequency for Load-Independent Output Current in Three-Coil Wireless Power Transfer System

    Directory of Open Access Journals (Sweden)

    Longzhao Sun

    2015-09-01

    Full Text Available Conditions for load-independent output voltage or current in two-coil wireless power transfer (WPT systems have been studied. However, analysis of load-independent output current in three-coil WPT system is still lacking in previous studies. This paper investigates the output current characteristics of a three-coil WPT system against load variations, and determines the operating frequency to achieve a constant output current. First, a three-coil WPT system is modeled by circuit theory, and the analytical expression of the root-mean-square of the output current is derived. By substituting the coupling coefficients, the quality factor, and the resonant frequency of each coil, we propose a method of calculating the frequency for load-independent output current in a three-coil WPT system, which indicates that there are two frequencies that can achieve load-independent output current. Experiments are conducted to validate these analytical results.

  14. Optimum systems design with random input and output applied to solar water heating

    Science.gov (United States)

    Abdel-Malek, L. L.

    1980-03-01

    Solar water heating systems are evaluated. Models were developed to estimate the percentage of energy supplied from the Sun to a household. Since solar water heating systems have random input and output queueing theory, birth and death processes were the major tools in developing the models of evaluation. Microeconomics methods help in determining the optimum size of the solar water heating system design parameters, i.e., the water tank volume and the collector area.

  15. Network-Based Output Tracking Control for a Class of T-S Fuzzy Systems That Can Not Be Stabilized by Nondelayed Output Feedback Controllers.

    Science.gov (United States)

    Zhang, Dawei; Han, Qing-Long; Jia, Xinchun

    2015-08-01

    This paper investigates network-based output tracking control for a T-S fuzzy system that can not be stabilized by a nondelayed fuzzy static output feedback controller, but can be stabilized by a delayed fuzzy static output feedback controller. By intentionally introducing a communication network that produces proper network-induced delays in the feedback control loop, a stable and satisfactory tracking control can be ensured for the T-S fuzzy system. Due to the presence of network-induced delays, the fuzzy system and the fuzzy tracking controller operate in an asynchronous way. Taking the asynchronous operation and network-induced delays into consideration, the network-based tracking control system is modeled as an asynchronous T-S fuzzy system with an interval time-varying delay. A new delay-dependent criterion for L2 -gain tracking performance is derived by using the deviation bounds of asynchronous normalized membership functions and a complete Lyapunov-Krasovskii functional. Applying a particle swarm optimization technique with the feasibility of the derived criterion, a novel design algorithm is presented to determine the minimum L2 -gain tracking performance and control gains simultaneously. The effectiveness of the proposed method is illustrated by performing network-based output tracking control of a Duffing-Van der Pol's oscillator. PMID:25222965

  16. Input-output characterization of an ultrasonic testing system by digital signal analysis

    Science.gov (United States)

    Williams, J. H., Jr.; Lee, S. S.; Karagulle, H.

    1986-01-01

    Ultrasonic test system input-output characteristics were investigated by directly coupling the transmitting and receiving transducers face to face without a test specimen. Some of the fundamentals of digital signal processing were summarized. Input and output signals were digitized by using a digital oscilloscope, and the digitized data were processed in a microcomputer by using digital signal-processing techniques. The continuous-time test system was modeled as a discrete-time, linear, shift-invariant system. In estimating the unit-sample response and frequency response of the discrete-time system, it was necessary to use digital filtering to remove low-amplitude noise, which interfered with deconvolution calculations. A digital bandpass filter constructed with the assistance of a Blackman window and a rectangular time window were used. Approximations of the impulse response and the frequency response of the continuous-time test system were obtained by linearly interpolating the defining points of the unit-sample response and the frequency response of the discrete-time system. The test system behaved as a linear-phase bandpass filter in the frequency range 0.6 to 2.3 MHz. These frequencies were selected in accordance with the criterion that they were 6 dB below the maximum peak of the amplitude of the frequency response. The output of the system to various inputs was predicted and the results were compared with the corresponding measurements on the system.

  17. Indirect techniques for adaptive input-output linearization of non-linear systems

    Science.gov (United States)

    Teel, Andrew; Kadiyala, Raja; Kokotovic, Peter; Sastry, Shankar

    1991-01-01

    A technique of indirect adaptive control based on certainty equivalence for input output linearization of nonlinear systems is proven convergent. It does not suffer from the overparameterization drawbacks of the direct adaptive control techniques on the same plant. This paper also contains a semiindirect adaptive controller which has several attractive features of both the direct and indirect schemes.

  18. Dynamic Output Feedback Control for Nonlinear Networked Control Systems with Random Packet Dropout and Random Delay

    Directory of Open Access Journals (Sweden)

    Shuiqing Yu

    2013-01-01

    Full Text Available This paper investigates the dynamic output feedback control for nonlinear networked control systems with both random packet dropout and random delay. Random packet dropout and random delay are modeled as two independent random variables. An observer-based dynamic output feedback controller is designed based upon the Lyapunov theory. The quantitative relationship of the dropout rate, transition probability matrix, and nonlinear level is derived by solving a set of linear matrix inequalities. Finally, an example is presented to illustrate the effectiveness of the proposed method.

  19. Multivariable output feedback robust adaptive tracking control design for a class of delayed systems

    Science.gov (United States)

    Mirkin, Boris; Gutman, Per-Olof

    2015-02-01

    In this paper, we develop a model reference adaptive control scheme for a class of multi-input multi-output nonlinearly perturbed dynamic systems with unknown time-varying state delays which is also robust with respect to an external disturbance with unknown bounds. The output feedback adaptive control scheme uses feedback actions only, and thus does not require a direct measurement of the command or disturbance signals. A suitable Lyapunov-Krasovskii type functional is introduced to design the adaptation algorithms and to prove stability.

  20. A linearized input-output representation of flexible multibody systems for control synthesis

    International Nuclear Information System (INIS)

    In this paper, a linearized input-output representation of flexible multibody systems is proposed in which an arbitrary combination of positions, velocities, accelerations, and forces can be taken as input variables and as output variables. The formulation is based on a nonlinear finite element approach in which a multibody system is modeled as an assembly of rigid body elements interconnected by joint elements such as flexible hinges and beams. The proposed formulation is general in nature and can be applied for prototype modeling and control system analysis of mechatronic systems. Application of the theory is illustrated through a detailed model development of an active vibration isolation system for a metrology frame of a lithography machine

  1. Cardiac repolarization during hypoglycaemia and hypoxaemia in healthy males: impact of renin-angiotensin system activity

    DEFF Research Database (Denmark)

    Due-Andersen, Rikke; Høi-Hansen, Thomas; Olsen, Niels Vidiendal; Larroude, Charlotte Ellen; Kanters, Jørgen Kim; Boomsma, Frans; Pedersen-Bjergaard, Ulrik; Thorsteinsson, Birger

    2008-01-01

    AIMS: Activity in the renin-angiotensin system (RAS) may influence the susceptibility to cardiac arrhythmia. To study the effect of basal RAS activity on cardiac repolarization during myocardial stress induced by hypoglycaemia or hypoxaemia in healthy humans. METHODS AND RESULTS: Ten subjects with...

  2. Excitation model of pacemaker cardiomyocytes of cardiac conduction system

    Science.gov (United States)

    Grigoriev, M.; Babich, L.

    2015-11-01

    Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

  3. Robust Output Regulation Of Uncertain Chaotic Systems With Input Magnitude And Rate Constraints

    Directory of Open Access Journals (Sweden)

    Velosa Carlos M.N.

    2015-12-01

    Full Text Available The problem of output regulation deserves a special attention particularly when it comes to the regulation of nonlinear systems. It is well-known that the problem is not always solvable even for linear systems and the fact that some demanding applications require not only magnitude but also rate actuator constraints makes the problem even more challenging. In addition, real physical systems might have parameters whose values can be known only with a specified accuracy and these uncertainties must also be considered to ensure robustness and on the other hand because they can be crucial for the type of behaviour exhibited by the system as it happens with the celebrated chaotic systems. The present paper proposes a robust control method for output regulation of chaotic systems with parameter uncertainties and subjected to magnitude and rate actuator constraints. The method is an extension of a work recently addressed by the same authors and consists in decomposing the nonlinear system into a stabilizable linear part plus a nonlinear part and in finding a control law based on the small-gain principle. Numerical simulations are performed to validate the effectiveness and robustness of the method using an aeronautical application. The output regulation is successfully achieved without exceeding the input constraints and stability is assured when the parameters are within the specified intervals. Furthermore, the proposed method does not require much computational effort because all the control parameters are computed offline.

  4. Output power stability of a HCN laser using a stepping motor for the EAST interferometer system

    Science.gov (United States)

    Zhang, J. B.; Wei, X. C.; Liu, H. Q.; Shen, J. J.; Zeng, L.; Jie, Y. X.

    2015-11-01

    The HCN laser on EAST is a continuous wave glow discharge laser with 3.4 m cavity length and 120 mW power output at 337 μ m wavelength. Without a temperature-controlled system, the cavity length of the laser is very sensitive to the environmental temperature. An external power feedback control system is applied on the HCN laser to stabilize the laser output power. The feedback system is composed of a stepping motor, a PLC, a supervisory computer, and the corresponding control program. One step distance of the stepping motor is 1 μ m and the time response is 0.5 s. Based on the power feedback control system, a stable discharge for the HCN laser is obtained more than eight hours, which satisfies the EAST experiment.

  5. Output power stability of a HCN laser using a stepping motor for the EAST interferometer system

    International Nuclear Information System (INIS)

    The HCN laser on EAST is a continuous wave glow discharge laser with 3.4 m cavity length and 120 mW power output at 337 μ m wavelength. Without a temperature-controlled system, the cavity length of the laser is very sensitive to the environmental temperature. An external power feedback control system is applied on the HCN laser to stabilize the laser output power. The feedback system is composed of a stepping motor, a PLC, a supervisory computer, and the corresponding control program. One step distance of the stepping motor is 1 μ m and the time response is 0.5 s. Based on the power feedback control system, a stable discharge for the HCN laser is obtained more than eight hours, which satisfies the EAST experiment

  6. High density, multi-range analog output Versa Module Europa board for control system applications.

    Science.gov (United States)

    Singh, Kundan; Das, Ajit Lal

    2014-01-01

    A new VMEDAC64, 12-bit 64 channel digital-to-analog converter, a Versa Module Europa (VME) module, features 64 analog voltage outputs with user selectable multiple ranges, has been developed for control system applications at Inter University Accelerator Centre. The FPGA (Field Programmable Gate Array) is the module's core, i.e., it implements the DAC control logic and complexity of VMEbus slave interface logic. The VMEbus slave interface and DAC control logic are completely designed and implemented on a single FPGA chip to achieve high density of 64 channels in a single width VME module and will reduce the module count in the control system applications, and hence will reduce the power consumption and cost of overall system. One of our early design goals was to develop the VME interface such that it can be easily integrated with the peripheral devices and satisfy the timing specifications of VME standard. The modular design of this module reduces the amount of time required to develop other custom modules for control system. The VME slave interface is written as a single component inside FPGA which will be used as a basic building block for any VMEbus interface project. The module offers multiple output voltage ranges depending upon the requirement. The output voltage range can be reduced or expanded by writing range selection bits in the control register. The module has programmable refresh rate and by default hold capacitors in the sample and hold circuit for each channel are charged periodically every 7.040 ms (i.e., update frequency 284 Hz). Each channel has software controlled output switch which disconnects analog output from the field. The modularity in the firmware design on FPGA makes the debugging very easy. On-board DC/DC converters are incorporated for isolated power supply for the analog section of the board. PMID:24517810

  7. Output Feedback and Single-Phase Sliding Mode Control for Complex Interconnected Systems

    OpenAIRE

    Yao-Wen Tsai; Huynh, Van Van

    2015-01-01

    This paper generalized a new sliding mode control (SMC) without reaching phase to solve two important problems in the stability of complex interconnected systems: (1) a decentralized controller that uses only output variables directly and (2) the stability of complex interconnected systems ensured for all time. A new sliding surface is firstly designed to construct a single-phase SMC in which the desired motion is determined from the initial time instant. A new lemma is secondly established f...

  8. Modular system for data acquisition and control of experiments with digital output

    Science.gov (United States)

    Calabria, Mauro F.; Deza, Roberto R.

    2010-11-01

    In the present work, the design of an efficient, modular, and scalable data acquisition and control system is described. It consists of an array of microcontrollers and memories, which feed a single concentrating unit whose information can be accessed by means of a universal series bus (USB) interface to be processed later on. Signal levels can be controlled through a set of digital potentiometers. This system is ideal for experiments with a large number of digital outputs.

  9. Adaptive Control for Uncertain Nonlinear Multi-Input Multi-Output Systems

    Science.gov (United States)

    Cao, Chengyu (Inventor); Hovakimyan, Naira (Inventor); Xargay, Enric (Inventor)

    2014-01-01

    Systems and methods of adaptive control for uncertain nonlinear multi-input multi-output systems in the presence of significant unmatched uncertainty with assured performance are provided. The need for gain-scheduling is eliminated through the use of bandwidth-limited (low-pass) filtering in the control channel, which appropriately attenuates the high frequencies typically appearing in fast adaptation situations and preserves the robustness margins in the presence of fast adaptation.

  10. Leontief Input-Output Technique and the Development of Agrilcutral Data Systems

    OpenAIRE

    HOWE, K. S.

    1981-01-01

    This paper suggests that a Leontief type input-output technique has an unrealized potential as the basis for efficient data systems. A model in the process of development for the UK livestock, meat, and meat products industry is used as an example. An expansive discussion of agricultural data systems is beyond the scope of this paper, but a thorough examination of the principal issues and an extensive bibliography are given by Barnard.

  11. OUTPUT VARIABLE STRUCTURE CONTROL FOR TIME-INVARIANT LINEAR TIME-DELAY SINGULAR SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Jifeng GUO; Cunchen GAO

    2007-01-01

    Synthesis and design of output variable structure controller for time-invariant linear time-delay singular system are studied. In the case that the system is regular and the system index is one, switching function with integral compensator and variable structure controller are designed, which guarantee that the sliding mode is asymptotically stable and the solution trajectory of the system arrives at the switching manifold in limited time. The design method is applicable to the systems which can be regularized. Finally, a numerical example is given to demonstrate effectiveness and simplicity of the design method.

  12. Globally Asymptotic Stability of Stochastic Nonlinear Systems with Time-Varying Delays via Output Feedback Control

    Directory of Open Access Journals (Sweden)

    Mingzhu Song

    2016-01-01

    Full Text Available We address the problem of globally asymptotic stability for a class of stochastic nonlinear systems with time-varying delays. By the backstepping method and Lyapunov theory, we design a linear output feedback controller recursively based on the observable linearization for a class of stochastic nonlinear systems with time-varying delays to guarantee that the closed-loop system is globally asymptotically stable in probability. In particular, we extend the deterministic nonlinear system to stochastic nonlinear systems with time-varying delays. Finally, an example and its simulations are given to illustrate the theoretical results.

  13. Semiconductor Light-Controlled Instrument Transducer with Direct PWM Output for Automatic Control Systems

    Directory of Open Access Journals (Sweden)

    F. J. De la Hidalga-W

    2013-01-01

    Full Text Available This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can beobtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and ametal (semitransparent gate oxide semiconductor capacitor (MOS-C.The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductorsubstrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification ofthe sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive andnegative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional tothe light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating rangeof this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors couldbe useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contactoptical position sensing for nulling and centering measurements.

  14. Ultra Low Complexity Soft Output Detector for Non-Binary LDPC Coded Large MIMO Systems

    CERN Document Server

    Suthisopapan, Puripong; Kasai, Kenta; Imtawil, Virasit

    2012-01-01

    The theoretic results of MIMO capacity tell us that the higher the number of antennas are employed, the higher the transmission rate is. This makes MIMO systems with hundreds of antennas very attractive but one of the major problems that obstructs such large dimensional MIMO systems from the practical realization is a high complexity of the MIMO detector. We present in this paper the new soft output MIMO detector based on matched filtering that can be applied to the large MIMO systems which are coded by the powerful non-binary LDPC codes. The per-bit complexity of the proposed detector is just 0.28% to that of low complexity soft output MMSE detector and scales only linearly with a number of antennas. Furthermore, the coded performances with small information length 800 bits are within 4.2 dB from the associated MIMO capacity.

  15. Computer program for single input-output, single-loop feedback systems

    Science.gov (United States)

    1976-01-01

    Additional work is reported on a completely automatic computer program for the design of single input/output, single loop feedback systems with parameter uncertainly, to satisfy time domain bounds on the system response to step commands and disturbances. The inputs to the program are basically the specified time-domain response bounds, the form of the constrained plant transfer function and the ranges of the uncertain parameters of the plant. The program output consists of the transfer functions of the two free compensation networks, in the form of the coefficients of the numerator and denominator polynomials, and the data on the prescribed bounds and the extremes actually obtained for the system response to commands and disturbances.

  16. Reliability Analysis of Production System of Fully-Mechanized Face Based on Output Statistic

    Institute of Scientific and Technical Information of China (English)

    CAI Qing-xiang; LI Nai-liang

    2005-01-01

    Production system of fully-mechanized face is a complicated system composed of human, machine and environment, meantime influenced by various random factors. Analyzing the reliability of system needs plentiful data by means of system faults statistic. Based on the viewpoint that shift output of fully-mechanized face is the result of various random factors' synthetical influence, the process of how to analyze its reliability was deduced by using probability theory, symbolic statistics theory and systematic reliability theory combined with the concrete case study in this paper. And it has been proved that this method is feasible and valuable.

  17. Output Tracking Control of Switched Hybrid Systems: A Fliess Functional Expansion Approach

    Directory of Open Access Journals (Sweden)

    Fenghua He

    2013-01-01

    Full Text Available The output tracking problem is investigated for a nonlinear affine system with multiple modes of continuous control inputs. We convert the family of nonlinear affine systems under consideration into a switched hybrid system by introducing a multiple-valued logic variable. The Fliess functional expansion is adopted to express the input and output relationship of the switched hybrid system. The optimal switching control is determined for a multiple-step output tracking performance index. The proposed approach is applied to a multitarget tracking problem for a flight vehicle aiming for one real target with several decoys flying around it in the terminal guidance course. These decoys appear as apparent targets and have to be distinguished with the approaching of the flight vehicle. The guidance problem of one flight vehicle versus multiple apparent targets should be considered if no large miss distance might be caused due to the limitation of the flight vehicle maneuverability. The target orientation at each time interval is determined. Simulation results show the effectiveness of the proposed method.

  18. Multi-input Multi-output System Identification Using Impulse Responses

    Science.gov (United States)

    Yamaguchi, Isao; Kasai, Tokio; Igawa, Hirotaka

    This paper presents a new algorithm for multi-input multi-output (MIMO) system identification in the time domain using impulse responses. The algorithm is suitable for the on-orbit system identification of spacecraft using the responses to thruster impulse inputs measured by typical satellite on-board sensors. The Eigensystem Realization Algorithm (ERA) realizes a multi-input multi-output (MIMO) system using asynchronous impulse responses in the time domain. Our new method identifies the input and output matrices of a MIMO collocated system by applying a recursive least-squares iteration scheme to refine the matrices obtained from conventional ERA. In this manner, the input matrix is considered to be constructed by the mode shape vectors and the actuator sensitivity matrix. A numerical simulation of an actual spacecraft, the Engineering Test Satellite-VI (ETS-VI), is performed to verify the algorithm. The nominal dynamics model of ETS-VI, which has six rigid body modes and fourteen elastic modes due to large flexible solar panels, is excited by six body-mounted thrusters, and the translational velocities and attitude rates are measured simultaneously. Our method successfully identifies all of the fourteen natural frequencies, damping ratios and mode shape vectors, confirming its validity.

  19. Growth, chlorophyll content and combined output value in eggplant/garlic relay intercropping systems

    International Nuclear Information System (INIS)

    A plastic tunnel experiment was conducted to investigate the effect of eggplant/garlic relay intercropping on the eggplant growth, chlorophyll content and combined output value in 2011 and 2012. The experimental design was randomized block with three replications consisting of eggplant monoculture (CK), eggplant relay intercropping with normal garlic (NG) and eggplant relay intercropping with green garlic (GG). It is showed that the eggplant stem in 2011 was first thicker then thinner in CK than NG, and it was always thicker in CK than GG; the plant height and stem diameter were both higher in relay intercropping treatments than CK in 2012. The chlorophyll content and chlorophyll a/b ratio were lower in NG compared with CK in most cases. In 2011, the eggplant yield and combined output value in GG were lower than CK, but in 2012, they were higher and the difference of combined output value between GG and CK was significant; for NG, they were always promoted both in 2011 and 2012. Different results between 2011 and 2012 may be due to the different time of green garlic uprooted in the spring. It is proved that uprooting green garlic before eggplant transplanting in 2012 was better to eggplant growth than uprooting them after eggplant transplanting in 2011. The conclusions are drawn that relay intercropping with normal or green garlic can improve the eggplant growth, increase the yield and the combined output value. As a result, eggplant/garlic relay intercropping systems may contribute to sustainable production of eggplant. (author)

  20. Input-output finite-time stabilisation of nonlinear stochastic system with missing measurements

    Science.gov (United States)

    Song, Jun; Niu, Yugang; Jia, Tinggang

    2016-09-01

    This paper considers the problem of the input-output finite-time stabilisation for a class of nonlinear stochastic system with state-dependent noise. The phenomenon of the missing measurements may occur when state signals are transmitted via communication networks. An estimating method is proposed to compensate the lost state information. And then, a compensator-based controller is designed to ensure the input-output finite-time stochastic stability (IO-FTSS) of the closed-loop system. Some parameters-dependent sufficient conditions are derived and the corresponding solving approach is given. Finally, numerical simulations are provided to demonstrate the feasibility and effectiveness of the developed IO-FTSS scheme.

  1. A Value-Added Based Measure of Health System Output and Estimating the Efficiency of OECD Health Systems

    OpenAIRE

    Dennis Petrie; Kam Ki Tang; Prasada Rao, D.S.

    2009-01-01

    Life expectancy at birth is the most commonly used measure for health system output. However, there are a number of reasons why it may be a poor proxy. First, life expectancy assumes a stationary population and thus does not take into account the current demographic structure of a country; and second, the output of a health system should be measured in terms of the value-added to the population’s health status rather than health status itself. The paper develops a new measure of health system...

  2. Laser cleaning of the output window in a laser ignition system for gas turbines

    OpenAIRE

    Griffiths, Jonathan David; Lawrence, Jonathan

    2012-01-01

    Laser ignition (LI) of both liquid fuels and gaseous combustible mixtures in gas turbines offers the potential for reduced emissions and increased reliability. During the combustion process, carbon and other by-products accumulate on the walls of the combustion chamber. For laser based ignition systems, this could potentially reduce the transmissive properties of the output window required for transmission of the laser radiation into the combustion chamber. Presented in this paper is an empir...

  3. Interpolation-based reduced-order models to predict transient thermal output for enhanced geothermal systems

    OpenAIRE

    Mudunuru, M. K.; Karra, S.; D. R. Harp; Guthrie, G. D.; Viswanathan, H. S.

    2016-01-01

    The goal of this paper is to assess the utility of Reduced-Order Models (ROMs) developed from 3D physics-based models for predicting transient thermal power output for an enhanced geothermal reservoir while explicitly accounting for uncertainties in the subsurface system and site-specific details. Numerical simulations are performed based on Latin Hypercube Sampling (LHS) of model inputs drawn from uniform probability distributions. Key sensitive parameters are identified from these simulatio...

  4. Adaptive Neural Control for a Class of Outputs Time-Delay Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    Ruliang Wang

    2012-01-01

    Full Text Available This paper considers an adaptive neural control for a class of outputs time-delay nonlinear systems with perturbed or no. Based on RBF neural networks, the radius basis function (RBF neural networks is employed to estimate the unknown continuous functions. The proposed control guarantees that all closed-loop signals remain bounded. The simulation results demonstrate the effectiveness of the proposed control scheme.

  5. Fuzzy neural network output maximization control for sensorless wind energy conversion system

    International Nuclear Information System (INIS)

    This paper presents the design of an online training fuzzy neural network (FNN) controller with a high-performance speed observer for the induction generator (IG). The proposed output maximization control is achieved without mechanical sensors such as the wind speed or position sensor, and the new control system will deliver maximum electric power with light weight, high efficiency, and high reliability. The estimation of the rotor speed is designed on the basis of the sliding mode control theory.

  6. A system for seismocardiography-based identification of quiescent heart phases: implications for cardiac imaging.

    Science.gov (United States)

    Wick, Carson A; Su, Jin-Jyh; McClellan, James H; Brand, Oliver; Bhatti, Pamela T; Buice, Ashley L; Stillman, Arthur E; Tang, Xiangyang; Tridandapani, Srini

    2012-09-01

    Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate. PMID:22581141

  7. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis

  8. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    Science.gov (United States)

    Dulloo, Abdul R.; Ruddy, Frank H.; Seidel, John G.; Petrović, Bojan

    2001-07-01

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis.

  9. Prototype Input and Output Data Elements for the Occupational Health and Safety Information System

    Science.gov (United States)

    Whyte, A. A.

    1980-01-01

    The National Aeronautics and Space Administration plans to implement a NASA-wide computerized information system for occupational health and safety. The system is necessary to administer the occupational health and safety programs and to meet the legal and regulatory reporting, recordkeeping, and surveillance requirements. Some of the potential data elements that NASA will require as input and output for the new occupational health and safety information system are illustrated. The data elements are shown on sample forms that have been compiled from various sources, including NASA Centers and industry.

  10. The Optimal Control for the Output Feedback Stochastic System at the Risk-Sensitive Cost

    Institute of Scientific and Technical Information of China (English)

    戴立言; 潘子刚; 施颂椒

    2003-01-01

    The optimal control of the partially observable stochastic system at the risk-sensitive cost is considered in this paper. The system dynamics has a general correlation between system and measurement noise. And the risk-sensitive cost contains a general quadratic term (with cross terms and extra linear terms). The explicit solution of such a problem is presented here using the output feedback control method. This clean and direct derivation enables one to convert such partial observable problems into the equivalent complete observable control problems and use the routine ways to solve them.

  11. Boolean modeling of neural systems with point-process inputs and outputs.

    Science.gov (United States)

    Marmarelis, Vasilis Z; Zanos, Theodoros P; Courellis, Spiros H; Berger, Theodore W

    2006-01-01

    This paper presents a novel modeling approach for neural systems with point-process inputs and outputs (binary time-series of 0's and 1's) that utilizes Boolean operators of modulo-2 multiplication and addition, corresponding to the logical AND and OR operations respectively. The form of the employed mathematical model is akin to a "Boolean-Volterra" model that contains the product terms of all relevant input lags in a hierarchical order, where terms of order higher than first represent nonlinear interactions among the various lagged values of each input point-process or among lagged values of various inputs (if multiple inputs exist) as they reflect on the output. The coefficients of this Boolean model are also binary variables that indicate the presence or absence of the respective term in each specific model/system. Simulations are used to explore the properties of such models and the feasibility of accurate estimation of such models from short data-records in the presence of noise (i.e. spurious spikes). The results demonstrate the feasibility of obtaining reliable estimates of such models, even in the presence of considerable noise in the input and/or output, thus making the proposed approach an attractive candidate for modeling neural systems in a practical context. PMID:17946091

  12. INIS (International Nuclear Information System) Database - output products and current situation in INIS system management in the Czech Republic

    International Nuclear Information System (INIS)

    After the Nuclear Information Centre Zbraslav terminated its performance as the Czech National INIS Centre, this responsibility was taken over directly by the Czech State Office for Nuclear Safety. The article informs the reader about output products available from the INIS system and gives links to staff responsible for administration of the INIS system in the Czech Republic

  13. Linear system identification - The application of Lion's identification scheme to a third order system with noisy input-output measurements

    Science.gov (United States)

    Brown, C. M., Jr.; Monopoli, R. V.

    1974-01-01

    A linear system identification technique developed by Lion is adapted for use on a third-order system with six unknown parameters and noisy input-output measurements. A digital computer is employed so that rapid identification takes place with only two state variable filters. Bias in the parameter estimates is partially eliminated by a signal-to-noise ratio testing procedure.

  14. Output-feedback sampled-data control design for linear parameter-varying systems with delay

    Science.gov (United States)

    Ramezanifar, Amin; Mohammadpour, Javad; Grigoriadis, Karolos M.

    2014-12-01

    In this paper, we address the sampled-data output-feedback control design problem for continuous-time linear parameter-varying systems with time-varying delay in the system states. Due to the combination of the plant's continuous-time dynamics and the controller's discrete-time dynamics connected through A/D and D/A converter devices, the closed-loop system is a hybrid system. In order to analyse this hybrid system from stability and performance perspectives we use the input-delay approach to map the closed-loop system into the continuous-time domain with delay in the states. This results in a closed-loop system containing two types of delays, the system internal delay and the one imposed by the mapping. Next, we use delay-dependent conditions for analysis of stability and ?-norm performance which result in a sampled-data control synthesis procedure. The proposed output-feedback sampled-data controller is obtained based on the solution to a linear matrix inequality optimisation problem using a set of appropriately defined slack variables. A numerical example of a milling machine is presented to demonstrate the viability of the proposed sampled-data control design method to satisfy the stability and performance objectives even with a varying sampling rate.

  15. Output power and efficiency of electromagnetic energy harvesting systems with constrained range of motion

    International Nuclear Information System (INIS)

    In some energy harvesting systems, the maximum displacement of the seismic mass is limited due to the physical constraints of the device. This is especially the case where energy is harvested from a vibration source with large oscillation amplitude (e.g., marine environment). For the design of inertial systems, the maximum permissible displacement of the mass is a limiting condition. In this paper the maximum output power and the corresponding efficiency of linear and rotational electromagnetic energy harvesting systems with a constrained range of motion are investigated. A unified form of output power and efficiency is presented to compare the performance of constrained linear and rotational systems. It is found that rotational energy harvesting systems have a greater capability in transferring energy to the load resistance than linear directly coupled systems, due to the presence of an extra design variable, namely the ball screw lead. Also, in this paper it is shown that for a defined environmental condition and a given proof mass with constrained throw, the amount of power delivered to the electrical load by a rotational system can be higher than the amount delivered by a linear system. The criterion that guarantees this favourable design has been obtained. (paper)

  16. Physiological role of transverse-axial tubular system in cardiac ventricular myocytes: a simulation study

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Šimurda, J.; Orchard, C.; Christé, G.

    Lyon : IEEE, 2005, s. 393-395. [Computers in cardiology. Lyon (FR), 25.09.2005-28.09.2005] Institutional research plan: CEZ:AV0Z20760514 Keywords : cardiac cell * tubular system * quantitative modelling Subject RIV: BO - Biophysics

  17. Natriuretic peptides in relation to the cardiac innervation and conduction system.

    Science.gov (United States)

    Hansson, Magnus

    2002-09-01

    During the past two decades, the heart has been known to undergo endocrine action, harbouring peptides with hormonal activities. These, termed "atrial natriuretic peptide (ANP)," "brain natriuretic peptide (BNP)," and "C-type natriuretic peptide (CNP)," are polypeptides mainly produced in the cardiac myocardium, where they are released into the circulation, producing profound hypotensive effects due to their diuretic, natriuretic, and vascular dilatory properties. It is, furthermore, well established that cardiac disorders such as congestive heart failure and different forms of cardiomyopathy are combined with increased expression of ANP and BNP, leading to elevated levels of these peptides in the plasma. Besides the occurrence of natriuretic peptides (NPs) in the ordinary myocardium, the presence of ANP in the cardiac conduction system has been described. There is also evidence of ANP gene expression in nervous tissue such as the nodose ganglion and the superior cervical ganglion of the rat, ganglia known to be involved in the neuronal regulation of the heart. Furthermore, in the mammalian heart, ANP appears to affect the cardiac autonomic nervous system by sympathoinhibitory and vagoexcitatory actions. This article provides an overview of the relationship between the cardiac conduction system, the cardiac innervation and NPs in the mammalian heart and provides data for the concept that ANP is also involved in neuronal cardiac regulation. PMID:12226807

  18. Design study of a cardiac-dedicated PET system

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hao, E-mail: penghao@mcmaster.ca [Department of Medical Physics, McMaster University, Canada L8S 4K1 (Canada); Department of Electrical and Computer Engineering, McMaster University, Canada L8S 4K1 (Canada)

    2015-04-11

    The work studies the feasibility of developing a cardiac-dedicated PET system using Monte Carlo simulation tools. The proposed system comprises a dual-panel geometry and both panels utilize fine crystal elements (~2–3 mm) to help improve high spatial resolution. The system performances were studied with respect to photon detection sensitivity, count-rate performances, spatial resolution, depth-of-interaction (DOI) capability, and potential contrast recovery improvement due to time-of-flight (TOF). For a 2:3 dual panel configuration (front panel: 24.0×18.0 cm{sup 2} and back panel: 36.0×27.0 cm{sup 2}), the system is able to achieve a peak photon sensitivity of ~13.0% at the location of the heart. For count-rate performances, the system is able to yield a continuous increase of noise equivalent count rate (NECR) as a function of the total activity of radiotracers between 10 mCi and 50 mCi. When crystal elements of 2×2×20 cm{sup 3} are deployed in the front panel and crystal elements of 3×3×20 cm{sup 3} are deployed in the back panel, the proposed system is not only able to revolve 2 mm diameter spheres in the image slices parallel to the panels but also demonstrates good resolution uniformity of less than 5%. On the other hand, significant resolution degradation occurs in the direction perpendicular to the panels due to the following two factors: limited angular coverage and finite DOI resolution. Such degradation was quantitatively analyzed for five different DOI resolutions (0 mm, 2.5 mm, 5 mm, 10 mm and 20 mm), as well as three different crystal configurations. Finally, the contrast study with a heart-like phantom (comprising lumen, aortic wall, myocardium and small lesions) indicates that TOF capability (time resolution: 250–500 ps) does not significantly improve image quality and lesion detectability, in terms of contrast-to-noise ratio (CNR)

  19. Left ventricular AV-plane displacement is preserved with lifelong endurance training and is the main determinant of maximal cardiac output

    DEFF Research Database (Denmark)

    Steding-Ehrenborg, Katarina; Boushel, Robert C; Calbet, José A; Åkeson, Per; Mortensen, Stefan P

    2015-01-01

    BACKGROUND: Age-related decline in cardiac function can be prevented or postponed by lifelong endurance training. However, effects of normal ageing as well as of lifelong endurance exercise on longitudinal and radial contribution to stroke volume are unknown. The aim of this study was to determine...

  20. NONINVASIVE CARDIAC OUTPUT MONITORING DURING EXERCISE TESTING: NEXFIN PULSE CONTOUR ANALYSIS COMPARED TO AN INERT GAS REBREATHING METHOD AND RESPIRED GAS ANALYSIS

    NARCIS (Netherlands)

    S.A. Bartels; W.J. Stok; R. Bezemer; R.J. Boksem; J Goudoever; T.G.V. Cherpanath; J.J. van Lieshout; B.E. Westerhof; J.M. Karemaker; C. Ince

    2011-01-01

    Purpose. Exercise testing is often used to assess cardiac function during physical exertion to obtain diagnostic information. However, this procedure is limited to measuring the electrical activity of the heart using electrocardiography and intermittent blood pressure (BP) measurements and does not

  1. Integred record system for standard reporting operations in pediatric cardiac surgey and complexity estimation

    OpenAIRE

    Taddei, Alessandro; Dalmiani, Stefano; Baldacci, Silvia; Piccini, Giacomo; Crucean, Andrea; Bernabei, Massimo; Luisi, Stefano; Vanini, Vittorio

    2002-01-01

    The Hospital Information System, first developed at our main institute for the integration of clinical, administrative and management resources in Cardiology, has been recently extended for use at our section specialised in Cardiac Surgery. Extension of the electronic medical record (EMR) to the management of patients admitted in Pediatric Cardiac Surgery started with the development of a system for reporting operations in structured form and for estimating their complexity, according to a mo...

  2. Robust Admissibilization of Descriptor Systems by Static Output-Feedback: An LMI Approach

    Directory of Open Access Journals (Sweden)

    M. Chaabane

    2011-01-01

    static output-feedback is studied in this paper and an approach to solve it is proposed. For this, sufficient conditions are derived for the closed-loop system to be admissible (i.e., stable, regular, and impulse-free. These conditions are expressed in terms of a strict Linear Matrix Inequality (LMI; so they are tractable using numerical computations. The proposed controller design methodology is based on two steps: the first is dedicated to synthesizing a classical state-feedback controller, which is used as the initial value for the second step, which uses an LMI problem to obtain static output-feedback controllers that give admissibility. Finally, a numerical example is given to illustrate the results.

  3. Output regulation for linear multi-agent systems with unmeasurable nodes

    International Nuclear Information System (INIS)

    The output regulation of linear multi-agent systems with partial unmeasurable agents is investigated in this paper. All the agents except the exosystem can be classified into two groups. Agents in the first group can be measured by themselves and their neighbors. State variables are not fully accessible for direct communication and full order Luenberger observers are constructed for the unmeasurable agents. We give a state feedback control law to solve the output regulation problem under the communication topologies based on both measurable and unmeasurable agents. The heterogeneous agents' synchronization problem is a general case of our results. Finally, examples are utilized to show the effectiveness of the obtained results. (interdisciplinary physics and related areas of science and technology)

  4. Multiuser detection algorithm based on belief propagation in multiple-input multiple-output systems

    Institute of Scientific and Technical Information of China (English)

    JIANG Wei; XIANG Haige

    2004-01-01

    In MIMO (multiple-input, multiple-output) systems, signals from different transmitting antennas interfere at each receiving antenna and multiuser detection (MUD)algorithms may be adopted to improve the system performance. This paper proposes a novel multiuser detection algorithm in MIMO systems based on the idea of "belief propagation" which has achieved great accomplishment in decoding of low-density parity-check codes. The proposed algorithm has a low computation complexity proportional to the square of transmitting/receiving antenna number. Simulation results show that under low signal-to-noise ratio (SNR) circumstances, the proposed algorithm outperforms the traditional linear minimum mean square error (MMSE) detector while it encounters a "floor" of bit error rate under high SNR circumstances. So the proposed algorithm is applicable to MIMO systems with channel coding and decoding. Although in this paper the proposed algorithm is derived in MIMO systems, obviously it can be applied to ordinary code-division multiple access (CDMA) systems.

  5. Cyberknife Relative Output Factor measurements using fiber-coupled luminescence, MOSFETS and RADPOS dosimetry system

    DEFF Research Database (Denmark)

    Ploquin, N.; Kertzscher Schwencke, Gustavo Adolfo Vladimir; Vandervoort, E.;

    2012-01-01

    from 5 to 60 mm. ROFs were also measured using a mobileMOSFET system (Best Medical Canada) and EBT1 and EBT2 GAFCHROMIC® (ISP, Ashland) radiochromic films. For cone sizes 12.5–60 mm all detector results were in agreement within the measurement uncertainty. The microMOSFET/RADPOS measurements (published...... 0.865 ± 0.3% for 5, 7.5 and 10 mm cones. Our study shows that the microMOSFET/RADPOS and optical fiber‐coupled RL dosimetry system are well suited for Cyberknife cone output factors measurements over the entire range of field sizes, provided that appropriate correction factors are applied for the...

  6. Cardiac arrhythmias and left ventricular hypertrophy in systemic hypertension

    International Nuclear Information System (INIS)

    Background: Hypertensive left ventricular hypertrophy (LVH) is associated with increased risk of arrhythmias and mortality. Objective was to investigate the prevalence of cardiac arrhythmias and LVH in systemic hypertension. Methods: In all subjects blood pressure was measured, electrocardiography and echocardiography was done. Holter monitoring and exercise test perform in certain cases. There were 500 hypertensive patients, 156 (31.2%) men and 344 (69%) women >30 years of age in the study. Among them 177 (35.4%) were diabetic, 224 (45%) were dyslipidemia, 188 (37.6%) were smokers, and 14 (3%) had homocysteinemia. Mean systolic BP (SBP) was 180 +- 20 mm Hg and diastolic BP (DBP) was 95 +- 12 in male and female patients. Left ventricular mass index (LVMI) was 119.2 +- 30 2 2gm/m in male while 103 +- 22 gm/m in female patients. Palpitation was seen in 126 (25%) male and 299 (59.8%) female patients. Atrial fibrillation was noted in 108 (21.6%) male and 125 (25%) female patients, 30 (6%) male and 82 (16.4%) female patients had atrial flutter. Ventricular tachycardia was noted in 37 (7.4%) male and 59 (11.8%) female patients. Holter monitoring showed significant premature ventricular contractions (PVC'S) in 109 (21.8%) male and 128 (25.69%) female patients while Holter showed atrial arrhythmias (APC'S) in 89 (17.8%) males and 119 (23.8%) females. Angiography findings diagnosed coronary artery disease in 119 (23.8%) with CAD male and 225 (45%) without CAD while 47 (9.4%) females presented with CAD and 109 (21.8%) without CAD. Conclusion: A significant association has been demonstrated between hypertension and arrhythmias. Diastolic dysfunction of the left ventricle, left atrial size and function, as well as LVH have been suggested as the underlying risk factors for supraventricular, ventricular arrhythmias and sudden death in hypertensives with LVH. (author)

  7. Computational system to estimate formation permeabilities and output curves of geothermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Moya, S.L.; Montoya, D. [CENIDET, Cuernavaca (Mexico). Departamento de Ingenieria Mecanica; Uribe, D. [Departamento de Desarrollo de Sistemas, Cuernavaca, Morelos (Mexico); Instituto Tecnologico de Zacatepec, Morelos (Mexico)

    2003-11-01

    Geothermal Inflow Performance Relationships (GIPR) numerically obtained may be used to estimate formation permeability at the geothermal well feed zone, by superimposition of the well inflow curve with different GIPR curves (geothermal inflow type-curves). Each type-curve reflects behavior which depends on the formation properties. The methodology does not require field measurement of the well inflow curve. The complete well inflow curve is obtained from a single wellhead or bottomhole measurement of mass flowrate (W), flowing pressure (P) and specific enthalpy (h), (W,P,h){sub 0}, and from the static pressure at the well feed zone (P{sub s}), by using two geothermal inflow performance dimensionless reference curves, one for mass productivity and another for thermal productivity. In order to facilitate the permeability diagnostic by means of this methodology, a computation system was developed which is described in this work. The system makes it possible to superimpose the geothermal well inflow curve on different geothermal inflow type-curves and then to select the best possible fit. Type-curves integrated to the system covering the temperature range 200-350{sup o}C in 25{sup o}C increments and Corey and linear relative permeabilities were considered. The system also allows estimation of the output curves associated with the well inflow curve by considering each calculated point of the well inflow curve as the input of a geothermal well flow simulator. The computation system shows instantaneously the estimated mass output curve (mass deliverability curve) for the well under analysis and the corresponding thermal power and specific enthalpy output curves. When it is required to validate the methodology for a particular well, the (W,P,h){sub 0} data may be from a previous discharge test and then the system will display the estimated output curves comparing them with all the field data of the corresponding discharge test. It is expected that this system can be

  8. Systems and methods for remote long standoff biometric identification using microwave cardiac signals

    Science.gov (United States)

    McGrath, William R. (Inventor); Talukder, Ashit (Inventor)

    2012-01-01

    Systems and methods for remote, long standoff biometric identification using microwave cardiac signals are provided. In one embodiment, the invention relates to a method for remote biometric identification using microwave cardiac signals, the method including generating and directing first microwave energy in a direction of a person, receiving microwave energy reflected from the person, the reflected microwave energy indicative of cardiac characteristics of the person, segmenting a signal indicative of the reflected microwave energy into a waveform including a plurality of heart beats, identifying patterns in the microwave heart beats waveform, and identifying the person based on the identified patterns and a stored microwave heart beats waveform.

  9. EVALUACIÓN ECOCARDIOGRÁFICA DEL GASTO CARDÍACO SISTÉMICO EN LA ATRESIA PULMONAR CON SEPTO INTERVENTRICULAR INTACTO / Echocardiographic evaluation of cardiac output in pulmonary atresia with intact ventricular septum

    Directory of Open Access Journals (Sweden)

    Giselle Serrano Ricardo

    2013-07-01

    hemodynamic performance, influencing cardiac output and generating potential conditions for short-term prognosis. Method: A descriptive, prospective and applied study was conducted. It included 43 patients who were referred to the William Soler Pediatric Cardiology Hospital from January 1992 to November 2011 with a diagnosis of the disease. In each subject, the profiles of eight echocardiographic variables were assessed, as well as the heart rate profile. Their level of association and mutual dependence were statistically assessed by simple regression models. Results: There are considerable variations in heart rate, in the volume index and in the ejection fraction of the patients´ left ventricle compared with those in the reference control group. Conclusions: The increased size of the atrial septal defect and the prolongation of transmitral diastasis favor left ventricular volume increment. Heart rate, the restrictive nature of the left ventricular myocardium and its ejection fraction are regulatory factors of cardiac output in this disease.

  10. Simple PID parameter tuning method based on outputs of the closed loop system

    Science.gov (United States)

    Han, Jianda; Zhu, Zhiqiang; Jiang, Ziya; He, Yuqing

    2016-04-01

    Most of the existing PID parameters tuning methods are only effective with pre-known accurate system models, which often require some strict identification experiments and thus infeasible for many complicated systems. Actually, in most practical engineering applications, it is desirable for the PID tuning scheme to be directly based on the input-output response of the closed-loop system. Thus, a new parameter tuning scheme for PID controllers without explicit mathematical model is developed in this paper. The paper begins with a new frequency domain properties analysis of the PID controller. After that, the definition of characteristic frequency for the PID controller is given in order to study the mathematical relationship between the PID parameters and the open-loop frequency properties of the controlled system. Then, the concepts of M-field and θ-field are introduced, which are then used to explain how the PID control parameters influence the closed-loop frequency-magnitude property and its time responses. Subsequently, the new PID parameter tuning scheme, i.e., a group of tuning rules, is proposed based on the preceding analysis. Finally, both simulations and experiments are conducted, and the results verify the feasibility and validity of the proposed methods. This research proposes a PID parameter tuning method based on outputs of the closed loop system.

  11. Simple PID parameter tuning method based on outputs of the closed loop system

    Science.gov (United States)

    Han, Jianda; Zhu, Zhiqiang; Jiang, Ziya; He, Yuqing

    2016-05-01

    Most of the existing PID parameters tuning methods are only effective with pre-known accurate system models, which often require some strict identification experiments and thus infeasible for many complicated systems. Actually, in most practical engineering applications, it is desirable for the PID tuning scheme to be directly based on the input-output response of the closed-loop system. Thus, a new parameter tuning scheme for PID controllers without explicit mathematical model is developed in this paper. The paper begins with a new frequency domain properties analysis of the PID controller. After that, the definition of characteristic frequency for the PID controller is given in order to study the mathematical relationship between the PID parameters and the open-loop frequency properties of the controlled system. Then, the concepts of M-field and θ-field are introduced, which are then used to explain how the PID control parameters influence the closed-loop frequency-magnitude property and its time responses. Subsequently, the new PID parameter tuning scheme, i.e., a group of tuning rules, is proposed based on the preceding analysis. Finally, both simulations and experiments are conducted, and the results verify the feasibility and validity of the proposed methods. This research proposes a PID parameter tuning method based on outputs of the closed loop system.

  12. Smoothing of Grid-connected Wind-Diesel Power Output Using Energy Capacitor System

    Directory of Open Access Journals (Sweden)

    Adel A. Elbaset

    2014-06-01

    Full Text Available This paper presents a small hybrid power system consists of two types of power generation; wind turbine and diesel generation, DG connected to power distribution system. The fluctuations like random nature of wind power, turbulent wind, and sudden changes in load demand create imbalances in power distribution that can affect the frequency and the voltage in the power system. So, addition of Energy capacitor System, ECS is useful for compensation of fluctuating power, since it is capable of controlling both active and reactive power simultaneously and can smooth the output power flow. Hence, this paper proposes herein a dynamic model and simulation of a grid connected wind/DG based-ECS with power flow controllers between load and generation. Moreover, the paper presents a study to analyze the leveling of output fluctuation of wind power with the installation of ECS. To control the power exchanged between the ECS system and the AC grid, a load Following Control, LFC based supervisor is proposed with the aim to minimize variations of the power generated by the diesel generator. The interesting performance of the proposed supervisor is shown with the help of simulations. The computer simulation program is confirmed on a realistic circuit model which implemented in the Simulink environment of Matlab and works as if on line.

  13. Activation of the Cardiac Renin-Angiotensin System in High Oxygen-Exposed Newborn Rats: Angiotensin Receptor Blockade Prevents the Developmental Programming of Cardiac Dysfunction.

    Science.gov (United States)

    Bertagnolli, Mariane; Dios, Anne; Béland-Bonenfant, Sarah; Gascon, Gabrielle; Sutherland, Megan; Lukaszewski, Marie-Amélie; Cloutier, Anik; Paradis, Pierre; Schiffrin, Ernesto L; Nuyt, Anne Monique

    2016-04-01

    Newborn rats exposed to high oxygen (O2), mimicking preterm birth-related neonatal stress, develop later in life cardiac hypertrophy, dysfunction, fibrosis, and activation of the renin-angiotensin system. Cardiac renin-angiotensin system activation in O2-exposed adult rats is characterized by an imbalance in angiotensin (Ang) receptors type 1/2 (AT1/2), with prevailing AT1 expression. To study the role of renin-angiotensin system in the developmental programming of cardiac dysfunction, we assessed Ang receptor expression during neonatal high O2 exposure and whether AT1 receptor blockade prevents cardiac alterations in early adulthood. Sprague-Dawley newborn rats were kept with their mother in 80% O2 or room air (control) from days 3 to 10 (P3-P10) of life. Losartan or water was administered by gavage from P8 to P10 (n=9/group). Rats were studied at P3 (before O2 exposure), P5, P10 (end of O2), and P28. Losartan treatment had no impact on growth or kidney development. AT1 and Ang type 2 receptors were upregulated in the left ventricle by high O2 exposure (P5 and P10), which was prevented by Losartan treatment at P10. Losartan prevented the cardiac AT1/2 imbalance at P28. Losartan decreased cardiac hypertrophy and fibrosis and improved left ventricle fraction of shortening in P28 O2-exposed rats, which was associated with decreased oxidation of calcium/calmodulin-dependent protein kinase II, inhibition of the transforming growth factor-β/SMAD3 pathway, and upregulation of cardiac angiotensin-converting enzyme 2. In conclusion, short-term Ang II blockade during neonatal high O2 prevents the development of cardiac alterations later in life in rats. These findings highlight the key role of neonatal renin-angiotensin system activation in the developmental programming of cardiac dysfunction induced by deleterious neonatal conditions. PMID:26857347

  14. A hybrid method for forecasting the energy output of photovoltaic systems

    International Nuclear Information System (INIS)

    Highlights: • We propose a novel hybrid technique for predicting the daily PV energy output. • Multiple linear regression, FFNN and GRNN artificial neural networks are used. • Stepwise regression is used to select the most relevant meteorological parameters. • SR-FFNN reduces the average dispersion and overall bias in prediction errors. • Accuracy metrics of hybrid models are better than those of single-stage models. - Abstract: The intermittent nature of solar energy poses many challenges to renewable energy system operators in terms of operational planning and scheduling. Predicting the output of photovoltaic systems is therefore essential for managing the operation and assessing the economic performance of power systems. This paper presents a new technique for forecasting the 24-h ahead stochastic energy output of photovoltaic systems based on the daily weather forecasts. A comparison of the performances of the hybrid technique with conventional linear regression and artificial neural network models has also been reported. Initially, three single-stage models were designed, namely the generalized regression neural network, feedforward neural network and multiple linear regression. Subsequently, a hybrid-modeling approach was adopted by applying stepwise regression to select input variables of greater importance. These variables were then fed to the single-stage models resulting in three hybrid models. They were then validated by comparing the forecasts of the models with measured dataset from an operational photovoltaic system. The accuracy of the each model was evaluated based on the correlation coefficient, mean absolute error, mean bias error and root mean square error values. Simulation results revealed that the hybrid models perform better than their corresponding single-stage models. Stepwise regression-feedforward neural network hybrid model outperformed the other models with root mean square error, mean absolute error, mean bias error and

  15. Robust output-feedback stabilization of a class of nonlinear systems with the nonlinearities of varied form

    Institute of Scientific and Technical Information of China (English)

    Sun Xiping; Wang Yongji

    2006-01-01

    The back-stepping designs based on confine functions are suggested for the robust output-feedback global stabilization of a class of nonlinear continuous systems; the proposed stabilizer is efficient for the nonlinear continuous systems confined by a bound function, the nonlinearities of the systems may be of varied forms or uncertain; the designed stabilizer is robust means that a class of nonlinear continuous systems can be stabilized by the same output feedback stabilization schemes; numerical simulation examples are given.

  16. A new output feedback synchronization theorem for a class of chaotic systems with a scalar transmitted signal

    Institute of Scientific and Technical Information of China (English)

    Lu Jun-Guo

    2006-01-01

    This paper proposes a new, simple and yet applicable output feedback synchronization theorem for a large class of chaotic systems. We take a linear combination of drive system state variables as a scale-driving signal. It is proved that synchronization between the drive and the response systems can be obtained via a simple linear output error feedback control. The linear feedback gain is a function of a free parameter. The approach is illustrated using the Rossler hyperchaotic systems and Chua's chaotic oscillators.

  17. Input-Output Feedback Linearization Cascade Controller Using Genetic Algorithm for Rotary Inverted Pendulum System

    Directory of Open Access Journals (Sweden)

    Iraj Hassanzadeh

    2008-01-01

    Full Text Available The Rotary Inverted Pendulum (RIP system is a significant classical problem of control engineering which has been investigated in the past decades. This study presents an optimum Input-Output Feedback Linearization (IOFL cascade controller utilized Genetic Algorithm (GA. Due to the non-minimum phase behavior of the system, IOFL controller leads to unstable internal dynamics. Therefore a cascade structure is proposed consisting IOFL controller for inner loop with PD controller forming the outer loop. The primary design goal is to balance the pendulum in an inverted position. The control criterion is to minimize the Integral Absolute Error (IAE of system angles. By minimizing the objective function related to IAE using Binary Genetic Algorithm (BGA, the optimal controller parameters can be assigned. The results verified capability and competent characteristics of the proposed controller. The method can be considered as a promising way for control of various similar nonlinear and under-actuated systems.

  18. Multi-Drive Paper System Control Based on Multi-Input Multi-Output PID Controller

    Directory of Open Access Journals (Sweden)

    Boumediène ALLAOUA

    2010-12-01

    Full Text Available Paper industries require several drives for paper processing. Electronic synchronization has to be ensured for quality of produced paper rolls. Several control strategies of multi-input multi-output (MIMO system (multivariable system have been suggested based on robust control or electronic emulation of mechanical line shaft. In this paper, a multivariable proportional-integral-derivative (PID controller applied on multi-drive paper system (MDPS. The proposed controller has superior feature, including easy implementation, stable convergence characteristics and very good computational performances efficiency. The multivariable PID controller is modeled in MATLAB environment. The speed control of MDPS (in our case is a triple drive system based on multivariable PID is more proficient in improving the speed loop response stability, the steady state error is reduced, the rising time is perfected and the disturbances do not affect the performances of driving motors with no overtaking.

  19. Brushless power generating system having reduced conducted emissions in output power

    International Nuclear Information System (INIS)

    This patent describes a brushless electrical power generating system. It comprises an exciter for producing alternating current from an exciter rotor; a rectifier mounted for rotation with the rotor for producing a rectified control current from the alternating current; a common mode inductor, coupled to the rectifier, for cancelling common mode noise components within the rectified control current; and a main generator, having a rotating field winding mounted on a main generator rotor excited by the control current and producing an alternating current power output from a stator

  20. Secure communication based on multi-input multi-output chaotic system with large message amplitude

    International Nuclear Information System (INIS)

    This paper deals with the problem of secure communication based on multi-input multi-output (MIMO) chaotic systems. Single input secure communication based on chaos can be easily extended to multiple ones by some combinations technologies, however all the combined inputs possess the same risk to be broken. In order to reduce this risk, a new secure communication scheme based on chaos with MIMO is discussed in this paper. Moreover, since the amplitude of messages in traditional schemes is limited because it would affect the quality of synchronization, the proposed scheme is also improved into an amplitude-independent one.

  1. Synchronization of the chaotic secure communication system with output state delay

    International Nuclear Information System (INIS)

    In this paper, we utilize a proper Lyapunov function and Lyapunov theorem, combined with LMIs method, in order to design a controller L, which ensures the synchronization between the transmission and the reception ends of the chaotic secure communication system with time-delay of output state. Meanwhile, for the purpose of increasing communication security, we encrypt and decrypt the original to-be-transmitted message with the techniques of n-shift cipher and public key. The result of simulation shows that the proposed method is able to synchronize the transmission and the reception ends of the system, and moreover, to recover the original message at the reception end. Therefore, the method proposed in this paper is effective and feasible to apply in the chaotic secure communication system.

  2. Output feedback adaptive fuzzy control of uncertain MIMO nonlinear systems with unknown input nonlinearities.

    Science.gov (United States)

    Shahnazi, Reza

    2015-01-01

    An adaptive fuzzy output feedback controller is proposed for a class of uncertain MIMO nonlinear systems with unknown input nonlinearities. The input nonlinearities can be backlash-like hysteresis or dead-zone. Besides, the gains of unknown input nonlinearities are unknown nonlinear functions. Based on universal approximation theorem, the unknown nonlinear functions are approximated by fuzzy systems. The proposed method does not need the availability of the states and an observer based on strictly positive real (SPR) theory is designed to estimate the states. An adaptive robust structure is used to cope with fuzzy approximation error and external disturbances. The semi-global asymptotic stability of the closed-loop system is guaranteed via Lyapunov approach. The applicability of the proposed method is also shown via simulations. PMID:25104646

  3. Fuzzy Controller for Matrix Converter System to Improve Its Quality of Output

    Directory of Open Access Journals (Sweden)

    N.Mahendran

    2010-10-01

    Full Text Available In this paper, Fuzzy Logic controller is developed for ac/ac Matrix Converter. Furthermore,Total Harmonic Distortion is reduced significantly. Space Vector Algorithm is a method to improve powerquality of the converter output. But its quality is limited to 86.7%.We are introduced a Cross coupled DQaxis controller to improve power quality. The Matrix Converter is an attractive topology for High voltagetransformation ratio. A Matlab / Simulink simulation analysis of the Matrix Converter system is provided.The design and implementation of fuzzy controlled Matrix Converter is described. This AC-AC system isproposed as an effective replacement for the conventional AC-DC-AC system which employs a two-steppower conversion.

  4. Fuzzy Controller for Matrix Converter System to Improve Its Quality of Output

    Directory of Open Access Journals (Sweden)

    N.Mahendran

    2010-10-01

    Full Text Available In this paper, Fuzzy Logic controller is developed for ac/ac Matrix Converter. Furthermore, Total Harmonic Distortion is reduced significantly. Space Vector Algorithm is a method to improve power quality of the converter output. But its quality is limited to 86.7%.We are introduced a Cross coupled DQ axis controller to improve power quality. The Matrix Converter is an attractive topology for High voltage transformation ratio. A Matlab / Simulink simulation analysis of the Matrix Converter system is provided. The design and implementation of fuzzy controlled Matrix Converter is described. This AC-AC system is proposed as an effective replacement for the conventional AC-DC-AC system which employs a two-step power conversion.

  5. Synchronization of the chaotic secure communication system with output state delay

    Energy Technology Data Exchange (ETDEWEB)

    Changchien, S.-K. [Department of Electrical Engineering, Chienkuo Technology University, Changhua 500, Taiwan (China)], E-mail: ccsk@ctu.edu.tw; Huang, C.-K.; Nien, H.-H.; Shieh, H.-W. [Department of Electrical Engineering, Chienkuo Technology University, Changhua 500, Taiwan (China)

    2009-02-28

    In this paper, we utilize a proper Lyapunov function and Lyapunov theorem, combined with LMIs method, in order to design a controller L, which ensures the synchronization between the transmission and the reception ends of the chaotic secure communication system with time-delay of output state. Meanwhile, for the purpose of increasing communication security, we encrypt and decrypt the original to-be-transmitted message with the techniques of n-shift cipher and public key. The result of simulation shows that the proposed method is able to synchronize the transmission and the reception ends of the system, and moreover, to recover the original message at the reception end. Therefore, the method proposed in this paper is effective and feasible to apply in the chaotic secure communication system.

  6. Differential effects of defibrillation on systemic and cardiac sympathetic activity

    OpenAIRE

    Bode, F; U. Wiegand; Raasch, W; Richardt, G.; Potratz, J

    1998-01-01

    Objective—To assess the effect of defibrillation shocks on cardiac and circulating catecholamines.
Design—Prospective examination of myocardial catecholamine balance during dc shock by simultaneous determination of arterial and coronary sinus plasma concentrations. Internal countershocks (10-34 J) were applied in 30 patients after initiation of ventricular fibrillation for a routine implantable cardioverter defibrillator test. Another 10 patients were externally cardioverted (50-360 J) for at...

  7. Input Output Symbolic Transition Systems Enriched by Program Calls and Contracts: a detailed example of vending machine

    OpenAIRE

    Boudhiba, Imen; Gaston, Christophe; Le Gall, Pascale; Prevosto, Virgile

    2015-01-01

    An Input Output Symbolic Transition System (IOSTS) specifies all expected sequences of input and output messages of a reactive system. Symbolic execution over this IOSTS then allows to generate a set of test cases that can exercise the various possible behaviors of the system it represents. In this paper, we extend the IOSTS framework with explicit program calls, possibly equipped with contracts specifying what the program is supposed to do. This approach bridges the gap between a model-based...

  8. Control Strategies for Smoothing of Output Power of Wind Energy Conversion Systems

    Science.gov (United States)

    Pratap, Alok; Urasaki, Naomitsu; Senju, Tomonobu

    2013-10-01

    This article presents a control method for output power smoothing of a wind energy conversion system (WECS) with a permanent magnet synchronous generator (PMSG) using the inertia of wind turbine and the pitch control. The WECS used in this article adopts an AC-DC-AC converter system. The generator-side converter controls the torque of the PMSG, while the grid-side inverter controls the DC-link and grid voltages. For the generator-side converter, the torque command is determined by using the fuzzy logic. The inputs of the fuzzy logic are the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and the generator torque. By means of the proposed method, the generator torque is smoothed, and the kinetic energy stored by the inertia of the wind turbine can be utilized to smooth the output power fluctuations of the PMSG. In addition, the wind turbines shaft stress is mitigated compared to a conventional maximum power point tracking control. Effectiveness of the proposed method is verified by the numerical simulations.

  9. Determinación y análisis comparativo de gasto cardíaco en enfermos críticos mediante Doppler transesofágico y termodilución en bolos: Experiencia preliminar Comparison of cardiac output measurement in critical patients using transesophageal Doppler or thermodilution: A preliminary report

    Directory of Open Access Journals (Sweden)

    Max Andresen H

    2005-07-01

    Full Text Available Background: Cardiac output can be measured non invasively by transesophageal Doppler. This is an alternative to measure it by thermodilution with a catheter in the pulmonary artery. Aim: To compare both methods of cardiac output measurement. Material and methods: Simultaneous measurement of cardiac output by transesophageal Doppler and thermodilution with a catheter in the pulmonary artery in four male critical patients, aged 60±12 years, hospitalized in a University Hospital. The Bland and Altman method to compare the concordance between two measurements, was used. Results: Forty measurements were performed. The results of both methods had a correlation coefficient of 0.98. According to the Bland and Altman method, the difference between both methods was -0.5 L with a precision of 0.52 L/min (95% confidence interval -1.51 to 0.52 L/min. Considering that a change between two sequential measurements is considered significant when the difference is more than 15%, both measurements agreed in 83% of cases, that there was a change in cardiac output. Conclusions:Transesophageal Doppler is a promising non invasive technique to measure cardiac output in critical care patients. It becomes a valid alternative to the thermodilution technique. This preliminary experience must be confirmed in a larger series

  10. Study on the DOP of Output Pulse in Optical Fiber Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    Yingwu Zhou; Lingwei Guo; Rui Huang; Ronghui Qu; Zujie Fang

    2003-01-01

    In this paper the expression of the output pulse Stokes vector is derived based on the Jones matrix model proposed by A.Orlandini et al. The basic properties of degree of polarization (DOP) for output pulse are investigated.

  11. Cross-correlation of output fluctuation and system-balancing cost in photovoltaic integration

    OpenAIRE

    Yuichi Ikeda; Kazuhiko Ogimoto

    2014-01-01

    The authors analysed the cross-correlation of photovoltaic (PV) output fluctuation for the actual PV output time series data in both the Tokyo area and the whole of Japan using the principal component analysis with the random matrix theory. Based on the obtained cross-correlation coefficients, the forecast error for PV output was estimated with/without considering the cross-correlations. Then the operation schedule of thermal plants is calculated to integrate PV output using the proposed unit...

  12. Analysis of Various Symbol Detection Techniques in Multiple-Input Multiple-Output System (MIMO)

    CERN Document Server

    Yadav, Shrikrishan; Pal, B L; 10.5121/acij.2012.3211

    2012-01-01

    Wireless communication is the fastest growing area of the communication industry. To keep swiftness with the indefinite increase in customers' demands and expectations, and the market competition among companies for the services offered,there is need for higher data rate along with reliable communication at low cost so that the applications can reach all. Until now, many technical challenges remain in designing robust and fast wireless systems that deliver the performance necessary to support emerging applications, due to the fact that wireless channels are frequency selective, power-limited, susceptible to noise and interference. Demand for high data rate and increasing applications offered by a wireless device calls for an effective method. Due to limit on the available bandwidth, there is a need for exploiting the available bandwidth in a way so that we get maximum advantage. Multiple-Input Multiple-Output system does exactly this thing by multiplying the data rate without any expansion in the bandwidth. T...

  13. Multi-Input Multi-Output (MIMO) control system with a state equation for fusion reactors

    International Nuclear Information System (INIS)

    In future fusion reactors, plasma control can be anticipated to be quite complicated because actuators and diagnostics would be limited because of extreme environmental conditions, such as high neutron fluxes. In addition, control parameters and actuators are not in simple one-to-one correspondences (e.g., NBI power affects not only plasma current but also fusion power). This results in the need of using multi-input multi-output control systems. To confront this problem, we have developed a control system design that involves an state equation. In this research, simulations were performed in which three plasma parameters (fusion power, plasma current, and plasma density) were controlled using three actuators (NBI power, amount of gas puff, and inductively driven current). Parameters for these actuators were determined from the state equation, and the plasma parameters were simultaneously controlled with sufficiently high accuracy. (author)

  14. Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS)

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Sven-Uwe

    2008-08-04

    The scope of this study are the development of an integrated simulation model for the estimation of the energy output of a deep Closed Loop Geothermal System (CLGS) and the discussion of several approaches to the enhancement of this output. Due to its closed character this kind of geothermal installation provides the opportunity of heat utilization even in dry and impermeable geological zones without any stimulation effort and the usage of external fluids. After a short introduction of the system itself and the limitations of other geothermal systems that are available, the investigations start with the description of the state-of-the-art with regard to the energy output analyses of the CLGS that have been done in the past. These are evaluated and their shortcomings are identified. The newly developed and introduced 3-dimensional approach of this study is a capable tool for the pre-feasibility phase of the project development of a CLGS. A geological/geothermal model summarizes selected relevant data and information about the project area in the form of a spatial data distribution. Thereby the formation boundaries are modelled as well as local in-homogeneities. The lithology can be modelled as well as the distribution of the thermal and physical properties of the rocks. The temperature distribution can be modelled using map or drill log data and be interpolated using geostatistical methods. After the combination of the geological/geothermal model and the technical model of the CLGS containing all relevant data with regard to the drill hole design, dimensions, casings and thermal properties of the installed materials, incl. the annuli, the thermal behaviour of the heat bearing fluid (HBF) flowing within the pipe system is simulated over time in connection with the simulation of the thermal behaviour of the surrounding rock mass. This core simulation is added by the afterwards processed scenario based energy supply simulation that calculates the amounts of energy

  15. System of image package input and output for neutron radiography based on PC IBM XT/AT

    International Nuclear Information System (INIS)

    System of acquisition and analysis of both statistic and dynamic images of neutron radiography includes NM IBM PC XT/AT, super vidicon, telecamera based video detector, color monitor and interface board of image input-output

  16. Static output feedback ℋ ∞ control for a fractional-order glucose-insulin system

    KAUST Repository

    N’Doye, Ibrahima

    2015-05-23

    This paper presents the ℋ static output feedback control of nonlinear fractional-order systems. Based on the extended bounded real lemma, the ℋ control is formulated and sufficient conditions are derived in terms of linear matrix inequalities (LMIs) formulation by using the fractional Lyapunov direct method where the fractional-order α belongs to 0 < α < 1. The control approach is finally applied to the regulation of the glucose level in diabetes type 1 treatment. Therefore, it is attempted to incorporate fractional-order into the mathematical minimal model of glucose-insulin system dynamics and it is still an interesting challenge to show, how the order of a fractional differential system affects the dynamics of the system in the presence of meal disturbance. Numerical simulations are carried out to illustrate our proposed results and show that the nonlinear fractional-order glucose-insulin systems are, at least, as stable as their integer-order counterpart in the presence of exogenous glucose infusion or meal disturbance. © 2015 Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg

  17. Logarithmic and power law input-output relations in sensory systems with fold-change detection.

    Science.gov (United States)

    Adler, Miri; Mayo, Avi; Alon, Uri

    2014-08-01

    Two central biophysical laws describe sensory responses to input signals. One is a logarithmic relationship between input and output, and the other is a power law relationship. These laws are sometimes called the Weber-Fechner law and the Stevens power law, respectively. The two laws are found in a wide variety of human sensory systems including hearing, vision, taste, and weight perception; they also occur in the responses of cells to stimuli. However the mechanistic origin of these laws is not fully understood. To address this, we consider a class of biological circuits exhibiting a property called fold-change detection (FCD). In these circuits the response dynamics depend only on the relative change in input signal and not its absolute level, a property which applies to many physiological and cellular sensory systems. We show analytically that by changing a single parameter in the FCD circuits, both logarithmic and power-law relationships emerge; these laws are modified versions of the Weber-Fechner and Stevens laws. The parameter that determines which law is found is the steepness (effective Hill coefficient) of the effect of the internal variable on the output. This finding applies to major circuit architectures found in biological systems, including the incoherent feed-forward loop and nonlinear integral feedback loops. Therefore, if one measures the response to different fold changes in input signal and observes a logarithmic or power law, the present theory can be used to rule out certain FCD mechanisms, and to predict their cooperativity parameter. We demonstrate this approach using data from eukaryotic chemotaxis signaling. PMID:25121598

  18. Logarithmic and power law input-output relations in sensory systems with fold-change detection.

    Directory of Open Access Journals (Sweden)

    Miri Adler

    2014-08-01

    Full Text Available Two central biophysical laws describe sensory responses to input signals. One is a logarithmic relationship between input and output, and the other is a power law relationship. These laws are sometimes called the Weber-Fechner law and the Stevens power law, respectively. The two laws are found in a wide variety of human sensory systems including hearing, vision, taste, and weight perception; they also occur in the responses of cells to stimuli. However the mechanistic origin of these laws is not fully understood. To address this, we consider a class of biological circuits exhibiting a property called fold-change detection (FCD. In these circuits the response dynamics depend only on the relative change in input signal and not its absolute level, a property which applies to many physiological and cellular sensory systems. We show analytically that by changing a single parameter in the FCD circuits, both logarithmic and power-law relationships emerge; these laws are modified versions of the Weber-Fechner and Stevens laws. The parameter that determines which law is found is the steepness (effective Hill coefficient of the effect of the internal variable on the output. This finding applies to major circuit architectures found in biological systems, including the incoherent feed-forward loop and nonlinear integral feedback loops. Therefore, if one measures the response to different fold changes in input signal and observes a logarithmic or power law, the present theory can be used to rule out certain FCD mechanisms, and to predict their cooperativity parameter. We demonstrate this approach using data from eukaryotic chemotaxis signaling.

  19. Analysis of Various Symbol Detection Techniques in Multiple-Input Multiple-Output System (MIMO

    Directory of Open Access Journals (Sweden)

    Shuchi Jani

    2012-04-01

    Full Text Available Wireless communication is the fastest growing area of the communication industry. To keep swiftness with the indefinite increase in customers’ demands and expectations, and the market competition among companies for the services offered ,there is need for higher data rate along with reliable communication at low cost so that the applications can reach all. Until now, many technical challenges remains in designing robust and fast wireless systems that deliver the performance necessary to support emerging applications, due to the fact that wireless channel is frequency selective, power-limited, susceptible to noise and interference. Demand for high data rate and increasing applications offered by a wireless device calls for an effective method. Due to limit on the available bandwidth, there is a need for exploiting the available bandwidth in a way so that we get maximum advantage. Multiple-Input Multiple-Output system does exactly this thing by multiplying the data rate without any expansion in the bandwidth. This system utilizes the spatial diversity property of the multi channel system. The reliable transmission requires symbols to be effectively recovered at the receiving end. V-BLAST detection technique is employed for this purpose. This paper depicted the advantages of using multiple antennas by exploitingsignal diversity offered by multipath effect and the system offers high spectral efficiency.

  20. End-expiration respiratory gating for a high-resolution stationary cardiac SPECT system

    Science.gov (United States)

    Chan, Chung; Harris, Mark; Le, Max; Biondi, James; Grobshtein, Yariv; Liu, Yi-Hwa; Sinusas, Albert J.; Liu, Chi

    2014-10-01

    Respiratory and cardiac motions can degrade myocardial perfusion SPECT (MPS) image quality and reduce defect detection and quantitative accuracy. In this study, we developed a dual respiratory and cardiac gating system for a high-resolution fully stationary cardiac SPECT scanner in order to improve the image quality and defect detection. Respiratory motion was monitored using a compressive sensor pillow connected to a dual respiratory-cardiac gating box, which sends cardiac triggers only during end-expiration phases to the single cardiac trigger input on the SPECT scanners. The listmode data were rebinned retrospectively into end-expiration frames for respiratory motion reduction or eight cardiac gates only during end-expiration phases to compensate for both respiratory and cardiac motions. The proposed method was first validated on a motion phantom in the presence and absence of multiple perfusion defects, and then applied on 11 patient studies with and without perfusion defects. In the normal phantom studies, the end-expiration gated SPECT (EXG-SPECT) reduced respiratory motion blur and increased myocardium to blood pool contrast by 51.2% as compared to the ungated images. The proposed method also yielded an average of 11.2% increase in myocardium to defect contrast as compared to the ungated images in the phantom studies with perfusion defects. In the patient studies, EXG-SPECT significantly improved the myocardium to blood pool contrast (p < 0.005) by 24% on average as compared to the ungated images, and led to improved perfusion uniformity across segments on polar maps for normal patients. For a patient with defect, EXG-SPECT improved the defect contrast and definition. The dual respiratory-cardiac gating further reduced the blurring effect, increased the myocardium to blood pool contrast significantly by 36% (p < 0.05) compared to EXG-SPECT, and further improved defect characteristics and visualization of fine structures at the expense of increased noise on

  1. End-expiration respiratory gating for a high-resolution stationary cardiac SPECT system

    International Nuclear Information System (INIS)

    Respiratory and cardiac motions can degrade myocardial perfusion SPECT (MPS) image quality and reduce defect detection and quantitative accuracy. In this study, we developed a dual respiratory and cardiac gating system for a high-resolution fully stationary cardiac SPECT scanner in order to improve the image quality and defect detection. Respiratory motion was monitored using a compressive sensor pillow connected to a dual respiratory–cardiac gating box, which sends cardiac triggers only during end-expiration phases to the single cardiac trigger input on the SPECT scanners. The listmode data were rebinned retrospectively into end-expiration frames for respiratory motion reduction or eight cardiac gates only during end-expiration phases to compensate for both respiratory and cardiac motions. The proposed method was first validated on a motion phantom in the presence and absence of multiple perfusion defects, and then applied on 11 patient studies with and without perfusion defects. In the normal phantom studies, the end-expiration gated SPECT (EXG-SPECT) reduced respiratory motion blur and increased myocardium to blood pool contrast by 51.2% as compared to the ungated images. The proposed method also yielded an average of 11.2% increase in myocardium to defect contrast as compared to the ungated images in the phantom studies with perfusion defects. In the patient studies, EXG-SPECT significantly improved the myocardium to blood pool contrast (p < 0.005) by 24% on average as compared to the ungated images, and led to improved perfusion uniformity across segments on polar maps for normal patients. For a patient with defect, EXG-SPECT improved the defect contrast and definition. The dual respiratory–cardiac gating further reduced the blurring effect, increased the myocardium to blood pool contrast significantly by 36% (p < 0.05) compared to EXG-SPECT, and further improved defect characteristics and visualization of fine structures at the expense of increased

  2. Interpolation-based reduced-order models to predict transient thermal output for enhanced geothermal systems

    CERN Document Server

    Mudunuru, M K; Harp, D R; Guthrie, G D; Viswanathan, H S

    2016-01-01

    The goal of this paper is to assess the utility of Reduced-Order Models (ROMs) developed from 3D physics-based models for predicting transient thermal power output for an enhanced geothermal reservoir while explicitly accounting for uncertainties in the subsurface system and site-specific details. Numerical simulations are performed based on Latin Hypercube Sampling (LHS) of model inputs drawn from uniform probability distributions. Key sensitive parameters are identified from these simulations, which are fracture zone permeability, well/skin factor, bottom hole pressure, and injection flow rate. The inputs for ROMs are based on these key sensitive parameters. The ROMs are then used to evaluate the influence of subsurface attributes on thermal power production curves. The resulting ROMs are compared with field-data and the detailed physics-based numerical simulations. We propose three different ROMs with different levels of model parsimony, each describing key and essential features of the power production cu...

  3. Systemic Leptin Produces a Long-Lasting Increase in Respiratory Motor Output in Rats

    Directory of Open Access Journals (Sweden)

    DonaldRMcCrimmon

    2013-02-01

    Full Text Available Leptin decreases food intake and increases energy expenditure. Leptin administration into the CNS of mice or rats increases alveolar ventilation and dysfunction in leptin signaling has been implicated in the hypoventilation that can accompany obesity. An increase in CO2 chemosensitivity has been implicated in this response but it is unclear whether ventilation is augmented when PCO2 is maintained constant. We examined the effects of intravenous leptin to test the hypothesis that systemic leptin administration in isoflurane anesthetized, mechanically ventilated and vagotomized rats would lead to a sustained increase in respiratory motor output that was independent of changes in end-tidal PCO2, body temperature or lung inflation pressure (an indicator of overall lung and chest wall compliance. In anesthetized Sprague-Dawley rats with end-tidal PCO2, lung compliance and rectal temperature maintained constant, injection of a bolus of leptin (0.25 mg, 0.5 mg/ml, i.v., followed over the next 1 hour by the intravenous infusion of an additional 0.25 mg, elicited a progressive increase in the peak amplitude of integrated phrenic nerve discharge lasting at least 1 hr beyond the end of the infusion. The increase peaked at 90 min at 58.3 ± 5.7% above baseline. There was an associated increase in the slope of the phrenic response to increasing inspired CO2.. There was also a moderate and sustained decrease in arterial pressure 9 ± 1.3 mmHg at 120 min, with no associated change in heart rate. These data indicate that leptin elicits a sustained increase in respiratory motor output that outlasts the administration leptin via a mechanism that does not require alterations in arterial PCO2, body temperature or systemic afferent feedback via the vagus nerves. Leptin may play an important role in matching alveolar ventilation to metabolism.

  4. Lactotripeptides effect on office and 24-h ambulatory blood pressure, blood pressure stress response, pulse wave velocity and cardiac output in patients with high-normal blood pressure or first-degree hypertension: a randomized double-blind clinical trial.

    Science.gov (United States)

    Cicero, Arrigo F G; Rosticci, Martina; Gerocarni, Beatrice; Bacchelli, Stefano; Veronesi, Maddalena; Strocchi, Enrico; Borghi, Claudio

    2011-09-01

    Contrasting data partially support a certain antihypertensive efficacy of lactotripeptides (LTPs) derived from enzymatic treatment of casein hydrolysate. Our aim was to evaluate this effect on a large number of hemodynamic parameters. We conducted a prospective double-blind randomized clinical trial, which included 52 patients affected by high-normal blood pressure (BP) or first-degree hypertension. We investigated the effect of a 6-week treatment with the LTPs isoleucine-proline-proline and valine-proline-proline at 3 mg per day, assumed to be functional food, on office BP, 24-h ambulatory BP monitoring (ABPM) values, stress-induced BP increase and cardiac output-related parameters. In the LTP-treated subjects, we observed a significant reduction in office systolic BP (SBP; -5±8 mm Hg, P=0.013) and a significant improvement in pulse wave velocity (PWV; -0.66±0.81 m s(-1), P=0.001; an instrumental biomarker of vascular rigidity). No effect on 24-h ABPM parameters and BP reaction to stress was observed from treatment with the combined LTPs. LTPs, but not placebo, were associated with a mild but significant change in the stroke volume (SV), SV index (markers of cardiac flow), the acceleration index (ACI) and velocity index (VI) (markers of cardiac contractility). No effect was observed on parameters related to fluid dynamics or vascular resistance. LTPs positively influenced the office SBP, PWV, SV, SV index, ACI and VI in patients with high-normal BP or first-degree hypertension. PMID:21753776

  5. WORKBENCH FOR CONTROL SYSTEMS TRIALS BASED ON VIPA 300 CONTROLLER AND ADVANTECH INPUT/OUTPUT CARD

    Directory of Open Access Journals (Sweden)

    M. V. Levinskyi

    2015-01-01

    Full Text Available The topic is about workbench creation for control systems trials based on VIPA 300 industrial PLC and model of control object which is implemented in MatLab Simulink program on PC. Connection between controller and the PC is provided by the Advantech PCI-1711 input/output card of discrete and analog signals. Object identification,control system synthesis, creation of control device structure and its parametrical identification, as a rule, is done on a PC in a modelling environment, e.g. in MatLab. But often, using this PC modelling, the hardware and software features of algorithms which were obtained during system synthesis are not considered in a specific industrial PLC.It is considered a good idea to use a composite version where obtained algorithms are tested in a real industrial PLC and control object is substituted by a model which is working on a PC in real time scale. In this case software realization of algorithms in a specific PLC are fully taken into account and substitution of real control object by itsmodel considerably reduces the costs for carrying out experiments and allows to study the system behavior when control object parameters and modes of operation vary greatly. The creation of workbench stipulates several stages: configuration and programming of industrial PLC VIPA 313 SC, installation and configuration of Advantech PCI- 1711 input/output card, tuning of Simulink modelling environment for working in real time scale using Real-Time Windows Target Library, testing of workbench by using constant and harmonic signals of different frequencies. Work results of virtual stabilization system are compared with combined version. In virtual stabilization system PID governor and control object are implemented in Simulink. In combined version control object is still implemented in Simulink and PID governor - in VIPA 313 SC controller (using functional block FB58 from Step7 standard library.

  6. Uncertainty Modeling and Robust Output Feedback Control of Nonlinear Discrete Systems: A Mathematical Programming Approach

    Directory of Open Access Journals (Sweden)

    Olav Slupphaug

    2001-01-01

    Full Text Available We present a mathematical programming approach to robust control of nonlinear systems with uncertain, possibly time-varying, parameters. The uncertain system is given by different local affine parameter dependent models in different parts of the state space. It is shown how this representation can be obtained from a nonlinear uncertain system by solving a set of continuous linear semi-infinite programming problems, and how each of these problems can be solved as a (finite series of ordinary linear programs. Additionally, the system representation includes control- and state constraints. The controller design method is derived from Lyapunov stability arguments and utilizes an affine parameter dependent quadratic Lyapunov function. The controller has a piecewise affine output feedback structure, and the design amounts to finding a feasible solution to a set of linear matrix inequalities combined with one spectral radius constraint on the product of two positive definite matrices. A local solution approach to this nonconvex feasibility problem is proposed. Complexity of the design method and some special cases such as state- feedback are discussed. Finally, an application of the results is given by proposing an on-line computationally feasible algorithm for constrained nonlinear state- feedback model predictive control with robust stability.

  7. Input-output tools: a language facility for interactive and real-time systems

    OpenAIRE

    Bos, van den, W.H.; Plasmeijer, Marinus J.; Hartel, Pieter H.

    1983-01-01

    A conceptual model is discussed which allows the hierarchic definition of high-level input driven objects, called input-output tools, from any set of basic input primitives. An input-output tool is defined as a named object. Its most important elements are the input rule, output rule, internal tool definitions, and a tool body consisting of executable statements. The input rule contains an expression with tool designators as operands and with operators allowing for sequencing, selection, inte...

  8. Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System

    Science.gov (United States)

    Santiago, Walter

    2004-01-01

    NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

  9. System for the experimental data acquisition, processing and output on the base of the double-input CAMAC modules

    International Nuclear Information System (INIS)

    A system for experimental data acquisition, processing and output developed on the base of the double-input CAMAC module is described. Use of the double-input on-line memory unit at the capacity of up to 64k bite for experimental data storage and an external input controller permitted to obtain the time of the data input and output cycle in the storage equal to 1.6 μs. Rates of experimental data acquisition and output do not depend on the computer response or CAMAC cycle duration. They are determined only by the potentialities of the functional moduls. Combination of operations on data acquisi tion, processing and output is possible. Library of subroutines assuring processing in an on-line system with the SM-4, SM-3, ''Electronika-60'' computers is developed for the system. Subroutiines of this library can be fetched from the code written in the FORTRAN and MLCROASSEMBER and they assure: input/output to/from the computer buffer storage, synchronization of ipput/output operations redout from the buffer storage to the computer storage, recording data from the storage to the huffer storage

  10. Real-time system for respiratory-cardiac gating in positron tomography

    International Nuclear Information System (INIS)

    A Macintosh-based signal processing system has been developed to support simultaneous respiratory and cardiac gating on the ECAT EXACT HR PET scanner. Using the Lab-View real-time software environment, the system reads analog inputs from a pneumatic respiratory bellows and an EGG monitor to compute an appropriate histogram memory location for the PET data. Respiratory state is determined by the bellows signal amplitude; cardiac state is based on the time since the last R-wave. These two states are used in a 2D lookup table to determine a combined respiratory-cardiac state. A 4-bit address encoding the selected histogram is directed from the system to the ECAT scanner, which dynamically switches the destination of tomograph events as respiratory-cardiac state changes. to Test the switching efficiency of the combined Macintosh/ECAT system, a rotating emission phantom was built. Acquisitions with 25 msec states while the phantom was rotating at 240 rpm demonstrate the system could effectively stop motion at this rate, with approximately 5 msec switching time between states

  11. Modelling Implicit Communication in Multi-Agent Systems with Hybrid Input/Output Automata

    Directory of Open Access Journals (Sweden)

    Marta Capiluppi

    2012-10-01

    Full Text Available We propose an extension of Hybrid I/O Automata (HIOAs to model agent systems and their implicit communication through perturbation of the environment, like localization of objects or radio signals diffusion and detection. To this end we decided to specialize some variables of the HIOAs whose values are functions both of time and space. We call them world variables. Basically they are treated similarly to the other variables of HIOAs, but they have the function of representing the interaction of each automaton with the surrounding environment, hence they can be output, input or internal variables. Since these special variables have the role of simulating implicit communication, their dynamics are specified both in time and space, because they model the perturbations induced by the agent to the environment, and the perturbations of the environment as perceived by the agent. Parallel composition of world variables is slightly different from parallel composition of the other variables, since their signals are summed. The theory is illustrated through a simple example of agents systems.

  12. Projections from the subparaventricular zone define four channels of output from the circadian timing system.

    Science.gov (United States)

    Vujovic, Nina; Gooley, Joshua J; Jhou, Thomas C; Saper, Clifford B

    2015-12-15

    The subparaventricular zone of the hypothalamus (SPZ) is the main efferent target of neural projections from the suprachiasmatic nucleus (SCN) and an important relay for the circadian timing system. Although the SPZ is fairly homogeneous cytoarchitecturally and neurochemically, it has been divided into distinct functional and connectional subdivisions. The dorsal subdivision of the SPZ (dSPZ) plays an important role in relaying signals from the SCN controlling body temperature rhythms, while the ventral subdivision (vSPZ) is critical for rhythms of sleep and locomotor activity (Lu et al. [] J Neurosci 21:4864-4874). On the other hand, the medial part of the SPZ receives input mainly from the dorsomedial SCN, whereas the lateral SPZ receives input from the ventrolateral SCN and the retinohypothalamic tract (Leak and Moore [] J Comp Neurol 433:312-334). We therefore investigated whether there are corresponding differences in efferent outputs from these four quadrants of the SPZ (dorsolateral, ventrolateral, dorsomedial, and ventromedial) by a combination of anterograde and retrograde tracing. We found that, while all four subdivisions of the SPZ share a similar backbone of major projection pathways to the septal region, thalamus, hypothalamus, and brainstem, each segment of the SPZ has a specific set of targets where its projections dominate. Furthermore, we observed intra-SPZ projections of varying densities between the four subdivisions. Taken together, this pattern of organization suggests that the circadian timing system may have several parallel neural outflow pathways that provide a road map for understanding how they subserve different functions. PMID:26010698

  13. Aggressive Cardiac Involvement in Systemic Lupus Erythematosus: A Case Report and a Comprehensive Literature Review

    Directory of Open Access Journals (Sweden)

    Reza Ashrafi

    2011-01-01

    Full Text Available Background. We present the case of a 35-year-old gentleman who presented with an aggressive cardiomyopathy with normal coronary arteries. He was later diagnosed with systemic lupus-related cardiomyopathy. Methods. We undertook an extensive review of the literature regarding cardiac manifestations of lupus and used over 100 journals to identify the key points in pathology, diagnosis, and treatment. Results. We have shown that cardiac lupus can be rapidly progressive and, unless treated early, can have severe consequences. The predominant pathologies are immune complex and accelerated atherosclerosis drive. Treatment comprised of high-level immunosuppression.

  14. Application and Nursing of Pulse Index Continuous Cardiac Output Monitoring in Patients with Post-cardiac Arrest Syndrome%脉波指示剂连续心排血量监测在心搏骤停后综合征患者中的应用与护理

    Institute of Scientific and Technical Information of China (English)

    陈淑兰; 刘刚; 张秋真; 陈秋恋

    2011-01-01

    Objective To investigate the application effect and nursing of the pulse index continuous cardiac output (PICCO) monitoring technique in patients with post-cardiac arrest syndrome (PCAS). Methods The precautions and nursing points were developed for the flowsheet of operation, cooperation for the vein catheterization and measurements. Results Of the 15 patients using the PICCO monitoring technique in early stage,no complication occurred ,except one patient died of multiple organ failure and 3 abandoned the treatment,and the rest 11 patients survived. Conclusion PCAS patients undergoing PICCO monitoring device in the early stage can efficiently assist the fluid management,maintain the vital signs of the patients,and save their lives.%目的 探讨脉波指示剂连续心排血量监测( pulse index continuous cardiac output,PICCO)在心搏骤停后综合征(postcardiac arrest syndrome,PCAS)患者中的应用效果及护理.方法 制定操作流程、置管配合、测量的注意事项和护理要点.结果 15例患者通过早期采用了PICCO监测,并采取了相应的护理措施,均未出现并发症,除了1例患者因多器官功能衰竭死亡外,3例患者放弃治疗,其余11例患者均存活.结论 对PCAS患者早期进行PICCO监测,能对患者进行更准确的血流动力学监测,可以有效协助液体管理,维持患者生命体征的稳定,挽救患者生命.

  15. Anatomy of the cardiac nervous system with clinical and comparative morphological implications.

    Science.gov (United States)

    Kawashima, Tomokazu

    2011-03-01

    Unlike autonomic nervous preservation in other surgeries for improving patient quality of life, autonomic cardiac nervous system (ACNS) preservation has been neglected in cardiovascular surgery because of technical difficulties and other unsolved issues. Because such ACNS preservation in cardiovascular surgery is anticipated in the future, detailed anatomical investigation of the human ACNS is required. Therefore, we have conducted morphological studies of the ACNS from macroscopic, clinical, and evolutionary anatomical viewpoints. In this study, I review detailed anatomical studies of the human ACNS together with their clinical implications. In addition, the evolutionary comparative anatomical significance of primate ACNS is also summarized to help understand and translate the findings of functional experiments to humans. These integrated findings will be the subject of a future study unifying molecular embryological and anatomical findings to clarify cardiac functions based on functional animal experiments, clinical applications such as improving surgery techniques and individual order-made surgery in cardiac surgery, and for future evaluation in regenerative medicine. PMID:21116884

  16. Beyond an Input/Output Paradigm for Systems: Design Systems by Intrinsic Geometry

    Directory of Open Access Journals (Sweden)

    Germano Resconi

    2014-11-01

    Full Text Available Given a stress-free system as a perfect crystal with points or atoms ordered in a three dimensional lattice in the Euclidean reference space, any defect, external force or heterogeneous temperature change in the material connection that induces stress on a previously stress-free configuration changes the equilibrium configuration. A material has stress in a reference which does not agree with the intrinsic geometry of the material in the stress-free state. By stress we mean forces between parts when we separate one part from another (tailing the system, the stress collapses to zero for any part which assumes new configurations. Now the problem is that all the new configurations of the parts are incompatible with each other. This means that close loop in the earlier configuration now is not closed and that the two paths previously joining the same two points now join different points from the same initial point so the final point is path dependent. This phenomenon is formally described by the commutators of derivatives in the new connection of the stress-free parts of the system under the control of external currents. This means that we lose the integrability property of the system and the possibility to generate global coordinates. The incompatible system can be represented by many different local references or Cartan moving Euclidean reference, one for any part of the system that is stress-free. The material under stress when is free assumes an equilibrium configuration or manifold that describes the intrinsic “shape” or geometry of the natural stress—the free state of the material. Therefore, we outline a design system by geometric compensation as a prototypical constructive operation.

  17. A large permissive regulatory domain exclusively controls Tbx3 expression in the cardiac conduction system

    NARCIS (Netherlands)

    van Weerd, Jan Hendrik; Badi, Ileana; van den Boogaard, Malou; Stefanovic, Sonia; van de Werken, Harmen J G; Gomez-Velazquez, Melisa; Badia-Careaga, Claudio; Manzanares, Miguel; de Laat, Wouter; Barnett, Phil; Christoffels, Vincent M

    2014-01-01

    RATIONALE: The evolutionary conserved Tbx3/Tbx5 gene cluster encodes T-box transcription factors that play crucial roles in the development and homeostasis of the cardiac conduction system in human and mouse. Both genes are expressed in overlapping patterns and function in strictly tissue-specific a

  18. A quantitative model of the cardiac ventricular cell incorporating the transverse-axial tubular system

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Christé, G.; Šimurda, J.

    2003-01-01

    Roč. 22, č. 3 (2003), s. 355-368. ISSN 0231-5882 R&D Projects: GA ČR GP204/02/D129 Institutional research plan: CEZ:AV0Z2076919 Keywords : cardiac cell * tubular system * quantitative modelling Subject RIV: BO - Biophysics Impact factor: 0.794, year: 2003

  19. Cardiac repolarization during hypoglycaemia in type 1 diabetes: impact of basal renin-angiotensin system activity

    DEFF Research Database (Denmark)

    Due-Andersen, Rikke; Høi-Hansen, Thomas; Larroude, Charlotte Ellen; Olsen, Niels Vidiendal; Kanters, Jørgen Kim; Boomsma, Frans; Pedersen-Bjergaard, Ulrik; Thorsteinsson, Birger

    2008-01-01

    AIMS: Hypoglycaemia-induced cardiac arrhythmias may be involved in the pathogenesis of the 'dead-in-bed syndrome' in patients with type 1 diabetes. Evidence suggests that the renin-angiotensin system (RAS) influences the occurrence of arrhythmias. The aim of this study was to explore if basal RAS...

  20. Systemic mastocytosis presenting as cardiac tamponade with CD25(+) pericardial mast cells.

    Science.gov (United States)

    Sukrithan, Vineeth K; Salamon, Jason N; Berulava, Giorgi; Sibinga, Nicholas E; Verma, Amit

    2016-03-01

    In this first-in-literature case, we describe a patient with Systemic mastocytosis presenting with life-threatening cardiac tamponade associated with the presence of aberrant mast cells in the pericardium. Procedures involving surgical incisions through the pericardium in such cases can lead to uncontrolled mast cell degranulation leading to circulatory collapse. PMID:27014452

  1. Non-sedating antihistamine drugs and cardiac arrhythmias : biased risk estimates from spontaneous reporting systems?

    NARCIS (Netherlands)

    De Bruin, M L; van Puijenbroek, E P; Egberts, A C G; Hoes, A W; Leufkens, H G M

    2002-01-01

    AIMS: This study used spontaneous reports of adverse events to estimate the risk for developing cardiac arrhythmias due to the systemic use of non-sedating antihistamine drugs and compared the risk estimate before and after the regulatory action to recall the over-the-counter status of some of these

  2. Proposed Methods to Increase the Output Efficiency of a Photovoltaic (PV System

    Directory of Open Access Journals (Sweden)

    Abdelhamid Midoun

    2010-07-01

    Full Text Available Lately, the use of solar energy has seen considerable development.Transformation in electric energy is one of its applications which attracts considerableinterest, owing to the fact that it makes it possible to solve a major problem in isolatedcities that lack electrical supply networks. For solar energy use, the current drawbackremains its high cost. This problem can be resolved through different improvements interms of power production. For that, different axis of research can be explored [1-3].Over the past few years, solar cells arrays (SCA have been connected to various loads in adirect coupled method. A PV module can produce the power at a point, called an operatingpoint, anywhere on the current- voltage (I-V curve. The coordinates of the Operating pointare the operating voltage and current. There is a unique point near the knee of the I-Vcurve, called a maximum power point (MPP, at which the module operates with themaximum efficiency and produces the maximum output power. The point of maximumpower is the desired operating point for a PV array to obtain maximum efficiency. A PVarray is usually oversized to compensate for a low power yield during winter months. Thismismatching between a PV module and a load requires further over-sizing of the PV arrayand thus increases the overall system cost [3-5]. To mitigate this problem, differentmethods have been developed [6-12]. A maximum power point tracker (MPPT can be usedto maintain the PV module’s operating point at the MPP. The system in a direct coupledmethod cannot always operate at maximum power point (MPP of the solar array when theload, irradiance or temperature changes. A PV-load coupling system should be able tomaximize the energy output of the PV generator, which should operate always at itsmaximum power point (MPP in order to achieve maximum global efficiency. Some authorshave supported the direct coupling between the PV generator and the load [2-3]. Severalmethods and algorithms to

  3. Development of a Customized Database Management System for the Cardiac Catheterization Laboratory

    OpenAIRE

    MILLER, MICHAEL R.

    1980-01-01

    A simple database management system has been developed for use by the Cardiac Catheterization Laboratory at University of Iowa Hospitals and Clinics. The system was developed with limited resources in a period of eight months. Major functions provided by the DBMS are data acquisition, report generation and selective retrieval by diagnosis. The modular design of the system provides for growth in the database without modification of existing programs. The project was divided into four stages: d...

  4. The second messenger system(s) mediating the secretion of atrial natriuretic peptide (ANP) from the isolated rat heart during rapid cardiac pacing.

    Science.gov (United States)

    Doubell, A F

    1989-01-01

    This study demonstrates that rapid cardiac pacing elevates Atrial Natriuretic Peptide (ANP) levels, independently from atrial stretch. The second messenger system mediating this response was examined. The phosphoinositide system, generally regarded to be important in mediating ANP release, was shown to play only a modulating role during rapid cardiac pacing. The main mediator would appear to be calcium, and a non-calmodulin dependent, calcium mediated system controlling ANP release during rapid cardiac pacing is suggested. PMID:2532285

  5. The effect of temporal variation on inputs and outputs of future-oriented land use systems in West Africa

    NARCIS (Netherlands)

    Hengsdijk, H.; Keulen, van H.

    2002-01-01

    The (semi-) arid area of West Africa is characterized by erratic rainfall that causes highly variable performances of cropping systems. This creates difficulties in strategic decision-making based on future-oriented production systems. In this paper, the degree of variation in inputs and outputs of

  6. Reduced-order observer-based output feedback control of nonlinear time-delay systems with prescribed performance

    Science.gov (United States)

    Hua, Changchun; Zhang, Liuliu; Guan, Xinping

    2016-04-01

    This paper studies the problem of output feedback control for a class of nonlinear time-delay systems with prescribed performance. The system is in the form of triangular structure with unmodelled dynamics. First, we introduce a reduced-order observer to provide the estimate of the unmeasured states. Then, by setting a new condition with the performance function, we design the state transformation with prescribed performance control. By employing backstepping method, we construct the output feedback controller. It is proved that the resulting closed-loop system is asymptotically stable and both transient and steady-state performance of the output are preserved with the changing supply function idea. Finally, a simulation example is conducted to show the effectiveness of the main results.

  7. Na/K pump regulation of cardiac repolarization: insights from a systems biology approach

    KAUST Repository

    Bueno-Orovio, Alfonso

    2013-05-15

    The sodium-potassium pump is widely recognized as the principal mechanism for active ion transport across the cellular membrane of cardiac tissue, being responsible for the creation and maintenance of the transarcolemmal sodium and potassium gradients, crucial for cardiac cell electrophysiology. Importantly, sodium-potassium pump activity is impaired in a number of major diseased conditions, including ischemia and heart failure. However, its subtle ways of action on cardiac electrophysiology, both directly through its electrogenic nature and indirectly via the regulation of cell homeostasis, make it hard to predict the electrophysiological consequences of reduced sodium-potassium pump activity in cardiac repolarization. In this review, we discuss how recent studies adopting the systems biology approach, through the integration of experimental and modeling methodologies, have identified the sodium-potassium pump as one of the most important ionic mechanisms in regulating key properties of cardiac repolarization and its rate dependence, from subcellular to whole organ levels. These include the role of the pump in the biphasic modulation of cellular repolarization and refractoriness, the rate control of intracellular sodium and calcium dynamics and therefore of the adaptation of repolarization to changes in heart rate, as well as its importance in regulating pro-arrhythmic substrates through modulation of dispersion of repolarization and restitution. Theoretical findings are consistent across a variety of cell types and species including human, and widely in agreement with experimental findings. The novel insights and hypotheses on the role of the pump in cardiac electrophysiology obtained through this integrative approach could eventually lead to novel therapeutic and diagnostic strategies. © 2013 Springer-Verlag Berlin Heidelberg.

  8. Autonomic Dysfunction Predicts Early Cardiac Affection in Patients with Systemic Sclerosis

    Directory of Open Access Journals (Sweden)

    Khaled M. Othman

    2010-05-01

    Full Text Available Objective: To detect the early preclinical alterations in cardiac autonomic control as well as altered cardiac function in systemic sclerosis (SSc patients and their relevance to the clinical features of the disease using noninvasive methods. Methods: 30 SSc patients and 15 healthy controls matched for age and sex underwent clinical examination, serological analysis, and echocardiographic assessment including Doppler flow imaging to evaluate cardiac function, and 24-hour Holter monitoring analyzed for arrhythmia and heart rate variability (HRV in the time and frequency domains. Results: The trans-mitral Doppler of early to atrial wave (E/A ratio was reversed in five patients (16.6% and the tricuspid E/A ratio was reversed in 10 patients (33.3%. Holter analysis for SSc patients revealed an increased prevalence of premature ventricular contractions (PVC $ 10/h (P = 0.02, supra-ventricular tachycardias (SVTs (P = 0.2, and total PVC count (P = 0.0000. Highly significant (P = 0.000 impairment in all HRV parameters was demonstrated in the SSc patients. Total skin thickness score (TSS, Raynaud’s phenomenon and anti-scleroderma 70 (anti-SCL70 showed significant positive correlations with all arrhythmia parameters, while showing a significant negative correlation with the impaired ventricular diastolic function and various HRV parameters. No correlation was found between arrhythmia and HRV parameters and disease duration, disease type, or presence of anti-centromere antibodies. Conclusion: Low heart rate variability, increased TSS and the presence of anti-SCL70 are correlated with preclinical cardiac involvement in SSc patients and may predict the likelihood of malignant arrhythmia and sudden cardiac death. Therefore, noninvasive HRV evaluation before clinical cardiac involvement in these patients might be beneficial when added to the clinical and laboratory assessments in detecting high-risk patients, and may allow for implementation of preventive

  9. Synthesis for robust synchronization of chaotic systems under output feedback control with multiple random delays

    International Nuclear Information System (INIS)

    Synchronization under output feedback control with multiple random time delays is studied, using the paradigm in nonlinear physics-Chua's circuit. Compared with other synchronization control methods, output feedback control with multiple random delay is superior for a realistic synchronization application to secure communications. Sufficient condition for global stability of delay-dependent synchronization is established based on the LMI technique. Numerical simulations fully support the analytical approach, in spite of the random delays

  10. Multivariable Proportional Integral Controllers for Multi-Inputs-Multi-Outputs Desalination System Fed by a Photovoltaic Generator

    Directory of Open Access Journals (Sweden)

    Abderrahmen B. Chaabene

    2010-01-01

    Full Text Available Process control is an essential part of the desalination industry that requires for driving at the optimum operating conditions an increase in the life time of the plant and reduction of the unit product cost. The desalination is a highly complex process, so that the majority of dynamic models are of the form of Multi-Inputs-Multi-Outputs (MIMO systems. Problem statement: Driving a MIMO system is a complex operation because of the interconnections between the inputs and the influence of each one of them on the system outputs. In this study, we present firstly the MIMO dynamic model that we have developed for a Reverse Osmosis (RO desalination system coupled to a photovoltaic generator, then we propose a PI controller based on a perfect decoupler. Approach: The purpose of this research was to apply a new control strategy based on a decoupled PI controller. The proposed control algorithm was investigated through computer simulation by using Simulink/Mathlab software. Results: The experimental results and simulations showed the efficiency of the proposed controller based on decoupling the input variables of the desalination system. The system outputs are well stabilized. Conclusion/Recommendations: The implementation of the multivariable PI control laws and the experimental results showed clearly the performances of this control strategy to drive the desalination systems and to correct rapidly the outputs behavior which can be influenced by many disturbed parameters.

  11. Disturbance observer based fault estimation and dynamic output feedback fault tolerant control for fuzzy systems with local nonlinear models.

    Science.gov (United States)

    Han, Jian; Zhang, Huaguang; Wang, Yingchun; Liu, Yang

    2015-11-01

    This paper addresses the problems of fault estimation (FE) and fault tolerant control (FTC) for fuzzy systems with local nonlinear models, external disturbances, sensor and actuator faults, simultaneously. Disturbance observer (DO) and FE observer are designed, simultaneously. Compared with the existing results, the proposed observer is with a wider application range. Using the estimation information, a novel fuzzy dynamic output feedback fault tolerant controller (DOFFTC) is designed. The controller can be used for the fuzzy systems with unmeasurable local nonlinear models, mismatched input disturbances, and measurement output affecting by sensor faults and disturbances. At last, the simulation shows the effectiveness of the proposed methods. PMID:26456728

  12. 动态投入产出系统的稳定性分析%STABILITY ANALYSIS OF THE DYNAMIC INPUT-OUTPUT SYSTEM

    Institute of Scientific and Technical Information of China (English)

    郭崇慧; 唐焕文

    2002-01-01

    The dynamic input-output model is well known in economic theory and practice.In this paper,the asymptotic stability and balanced growth solutions of the dynamic input-output system are considered.Under some natural assumptions which do not require the technical coefficient matrix to be indecomposable,it has been proved that the dynamic input-output system is not asymptotically stable and the closed dynamic input-output model has a balanced growth solution.

  13. Enhancing efficiency and power output of gas turbines using either renewable energy or heat recovery cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Nasser, A.E.M. [Higher Technological Inst., Tenth of Ramadan (Egypt). Dept. of Mechanical Engineering

    2006-07-01

    An absorption system to cool intake air to the compressor of an air conditioning system was presented. The system used both solar energy and the waste heat of the exhaust gases to obtain higher temperatures during the summer months. The lithium bromide-water absorption system increased power output by more than 20 per cent during the summer months without consuming more fuel. The system was designed to conserve energy and output power in gas turbine power stations. The system operated by using hot effluent gases leaving the turbine and entered the flue stacks, where heat exchangers recovered the heat energy. Excess electricity produced by the turbine was then used to cool the ambient air before it entered the compressor. Studies have confirmed that the system is financially viable and suited for use in Arabian Gulf countries where temperatures regularly exceed 40 degrees C. 6 refs., 6 figs.

  14. A model of cardiac tissue as a conductive system with interacting pacemakers and refractory time

    OpenAIRE

    Loskutov, Alexander; Rybalko, Sergei; Zhuchkova, Ekaterina

    2002-01-01

    A model of the heart tissue as a conductive system with two interacting pacemakers and a refractory time, is proposed. In the parametric space of the model the phase locking areas are investigated in detail. Obtained results allow us to predict the behaviour of excitable systems with two pacemakers depending on the type and intensity of their interaction and the initial phase. Comparison of the described phenomena with intrinsic pathologies of cardiac rhythms is presented.

  15. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    Science.gov (United States)

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  16. Experimental research on light output characteristic of scintillator applied in pulsed γ-ray and fast neutron imaging systems

    International Nuclear Information System (INIS)

    In the intense pulsed radiation fields, the scintillator is generally used as the converter of the γ-ray or fast neutron signals from the source region in an imaging system. The light output characteristic of the scintillator as well as the light collection efficiency of the optic imaging system to the scintillator is the key parameter for determining the system's sensitivity and dynamic range. The relative light output of five types of inorganic/plastic scintillators such as YAG : Ce3+, ST401, EJ200, EJ260 and EJ264, was obtained through studying the rule about the output current variation of the scintillator and photon-sensitive instrument in various coupling conditions. The influence of coupling distance on the light collection efficiency of the optic imaging system was also studied. The results indicate that the measured value of the scintillator light output achieves good consistency in conditions of different coupling distances, and the anisotropy of scintillating photon emission must be considered to determine the light collection efficiency of the optic imaging system. (authors)

  17. Indirect calorimetry can be used to measure cardiac output in septic patients? A calorimetria indireta pode ser utilizada para medir o débito cardíaco em pacientes sépticos?

    Directory of Open Access Journals (Sweden)

    Maria Auxiliadora Martins

    2008-01-01

    Full Text Available PURPOSE: The aim of this study was to compare two different cardiac output (CO monitoring systems based on the thermodilution principle (Thermo-CO and indirect calorimetry (Fick mixed-CO in septic patients. METHODS: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Nineteen patients aged on average 45.4 ± 21.5 years were enrolled in the study. Four series of hourly measurements by the two techniques were carried out simultaneously. RESULTS: No significant differences were observed between Thermo-CO and Fick mixed-CO (7.0 ± 1.8 L.min-1 and 6.4 ± 1.7 L.min-1.. Parallel analysis of Fick mixed-CO and Fick atrial-CO was performed introducing a correction factor for the eight atrial samples in order to adjust the values of oxygen saturation obtained from atrial blood (Fick corrected atrial-CO to those obtained from mixed venous blood. No significant differences could be detected between Fick mixed-CO and Fick corrected atrial-CO. The correlation coefficients of Thermo CO/Fick mixed-CO and Fick mixed-CO/Fick corrected atrial-CO were 0.84 and 0.94, respectively. CONCLUSION: We observed that the agreement between the two methods was satisfactory on the basis of the decisions made for treatment. Indirect calorimetry is useful to measure CO in patients with septic shock.OBJETIVO: O objetivo deste estudo foi comparar as medidas do débito cardíaco (DC obtidas pela termodiluição (DC-termo e pela calorimetria indireta (DC-Fick misto em pacientes com choque séptico. MÉTODOS: Estudo prospectivo em pacientes sépticos internados em unidade de terapia intensiva de um hospital universitário. Foram estudados 19 pacientes (45,4 ± 21,5 anos. Foram realizadas quatro séries de medidas do DC pelos dois métodos, simultaneamente. RESULTADOS: Não houve diferenças significativas entre os valores do DC-termo e DC-Fick misto (7,0 ± 1,8 L.min-1 e 6,4 ± 1,7 L.min-1, respectivamente. Na avaliação dos oito casos

  18. Robust output tracking control of a class of non-minimum phase systems and application to VTOL aircraft

    Science.gov (United States)

    Su, Shanwei; Lin, Yan

    2011-11-01

    In this article, we study the output tracking control of a class of MIMO nonlinear non-minimum phase systems in the presence of input disturbances. In order to attenuate the effects of disturbances, the method of uncertainty and disturbance estimator (UDE) is extended to the controller design for non-minimum phase systems. Due to the fact that the accumulated disturbances is composed of internal states and external disturbances, a different stability analysis is given, and the overall closed-loop system is proved to be semi-globally stable. The proposed state-feedback controller not only forces system outputs to asymptotically track desired trajectories, but also drives the unstable internal dynamics to follow bounded and causal ideal internal dynamics (IID) solved via stable system centre (SSC) method. Simulation results demonstrate that the proposed controller achieves excellent tracking and disturbance rejection performance via the example of VTOL aircraft which has been the benchmark of nonlinear non-minimum phase systems.

  19. Construction of a computational anatomical model of the peripheral cardiac conduction system.

    Science.gov (United States)

    Sebastian, Rafael; Zimmerman, Viviana; Romero, Daniel; Frangi, Alejandro F

    2011-12-01

    A methodology is presented here for automatic construction of a ventricular model of the cardiac conduction system (CCS), which is currently a missing block in many multiscale cardiac electromechanic models. It includes the His bundle, left bundle branches, and the peripheral CCS. The algorithm is fundamentally an enhancement of a rule-based method known as the Lindenmayer systems (L-systems). The generative procedure has been divided into three consecutive independent stages, which subsequently build the CCS from proximal to distal sections. Each stage is governed by a set of user parameters together with anatomical and physiological constrains to direct the generation process and adhere to the structural observations derived from histology studies. Several parameters are defined using statistical distributions to introduce stochastic variability in the models. The CCS built with this approach can generate electrical activation sequences with physiological characteristics. PMID:21896384

  20. Dipyridamole thallium imaging for detecting cardiac involvement in patients with systemic sclerosis (scleroderma)

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Yoshio; Matsubara, Noboru; Tani, Akihiro; Morozumi, Takakazu; Hori, Masatsugu; Kitabatake, Akira; Kamada, Takenobu; Kimura, Kazufumi; Kozuka, Takahiro (Osaka Univ. (Japan). Faculty of Medicine)

    1990-02-01

    Dipyridamole thallium-201 imaging was carried out in 21 patients with progressive systemic sclerosis (PSS) to assess its value in detecting impaired myocardium and coronary microcirculation associated with PSS. Depending upon the degree of cardiac function, the patients were classified as having either ejection fraction of 50% or more (Group I, n=17) or less than 50% (Group II, n=4). In Group I, four patients had transient defect in which perfusion defects were seen on early images but not seen on delayed images; three had reverse redistribution in which defects were not seen on early images but seen on delayed images; and three had persistent defects which were seen on both early and delayed images. A decreased washout of thallium-201 was seen in 9 patients. In an analysis of both perfusion defects and washout rate, 13 patients (76%) in Group I were found to have abnormal findings. This suggests that disturbed coronary microcirculation or impaired myocardium may frequently develop even when EF is normal. All of the patients categorized as having a decreased cardiac function (Group II) had perfusion defect, suggesting the presence of myocardial fibrosis. In PSS, deterioration of cardiac function seemed to be associated with progression of myocardial fibrosis. Dipyridamole thallium imaging may be a sensitive method for detecting cardiac lesions in PSS. It also has the potential for detecting decreased coronary flow reserve or slightly impaired myocardium even without decreased EF. (N.K.).

  1. Modulation of Cardiac Autonomic Dysfunction in Ischemic Stroke following Ayurveda (Indian System of Medicine Treatment

    Directory of Open Access Journals (Sweden)

    Sriranjini Sitaram Jaideep

    2014-01-01

    Full Text Available Objectives. Cardiac autonomic dysfunction in stroke has implications on morbidity and mortality. Ayurveda (Indian system of medicine describes stroke as pakshaghata. We intended to study the effect of Ayurveda therapies on the cardiac autonomic dysfunction. Methods. Fifty patients of ischemic stroke (middle cerebral artery territory (mean age 39.26 ± 9.88 years; male 43, female 7 were recruited within one month of ictus. All patients received standard allopathic medications as advised by neurologist. In addition, patients were randomized to receive physiotherapy (Group I or Ayurveda treatment (Group II for 14 days. Continuous electrocardiogram and finger arterial pressure were recorded for 15 min before and after treatments and analyzed offline to obtain heart rate and blood pressure variability and baroreflex sensitivity (BRS. Results were analysed by RMANOVA. Results. Patients in Group II showed statistically significant improvement in cardiac autonomic parameters. The standard deviation of normal to normal intervals,and total and low frequency powers were significantly enhanced (F=8.16, P=0.007, F=9.73, P=0.004, F=13.51, and P=0.001, resp.. The BRS too increased following the treatment period (F=10.129, P=0.004. Conclusions. The current study is the first to report a positive modulation of cardiac autonomic activity after adjuvant Ayurveda treatment in ischemic stroke. Further long term studies are warranted.

  2. Dynamic characteristics of an orthogonal turbine and output-control systems for TPP with high-voltage frequency converter

    International Nuclear Information System (INIS)

    A mathematical description of a closed control system with allowance for pressure fluctuations in the head system, which makes it possible to analyze the regime stability of orthogonal generating sets at tidal electric power plants when operating in the complete range of heads, outputs, and rotational speeds, and to select parameters of the control system, is obtained for an orthogonal hydroturbine and a generator with a load regulator.

  3. A concurrent diagnosis of microbiological food safety output and food safety management system performance: Cases from meat processing industries

    NARCIS (Netherlands)

    Luning, P.A.; Jacxsens, L.; Rovira, J.; Oses Gomez, S.; Uyttendaele, M.; Marcelis, W.J.

    2011-01-01

    Stakeholder requirements force companies to analyse their food safety management system (FSMS) performance to improve food safety. Performance is commonly analysed by checking compliance against preset requirements via audits/inspections, or actual food safety (FS) output is analysed by microbiologi

  4. SEMI-BLIND CHANNEL ESTIMATION OF MULTIPLE-INPUT/MULTIPLE-OUTPUT SYSTEMS BASED ON MARKOV CHAIN MONTE CARLO METHODS

    Institute of Scientific and Technical Information of China (English)

    Jiang Wei; Xiang Haige

    2004-01-01

    This paper addresses the issues of channel estimation in a Multiple-Input/Multiple-Output (MIMO) system. Markov Chain Monte Carlo (MCMC) method is employed to jointly estimate the Channel State Information (CSI) and the transmitted signals. The deduced algorithms can work well under circumstances of low Signal-to-Noise Ratio (SNR). Simulation results are presented to demonstrate their effectiveness.

  5. On the generalization of linear least mean squares estimation to quantum systems with non-commutative outputs

    Energy Technology Data Exchange (ETDEWEB)

    Amini, Nina H. [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States); CNRS, Laboratoire des Signaux et Systemes (L2S) CentraleSupelec, Gif-sur-Yvette (France); Miao, Zibo; Pan, Yu; James, Matthew R. [Australian National University, ARC Centre for Quantum Computation and Communication Technology, Research School of Engineering, Canberra, ACT (Australia); Mabuchi, Hideo [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States)

    2015-12-15

    The purpose of this paper is to study the problem of generalizing the Belavkin-Kalman filter to the case where the classical measurement signal is replaced by a fully quantum non-commutative output signal. We formulate a least mean squares estimation problem that involves a non-commutative system as the filter processing the non-commutative output signal. We solve this estimation problem within the framework of non-commutative probability. Also, we find the necessary and sufficient conditions which make these non-commutative estimators physically realizable. These conditions are restrictive in practice. (orig.)

  6. Decentralized robust H-infinity descriptor output feedback control for value-bounded uncertain descriptor large-scale systems

    Institute of Scientific and Technical Information of China (English)

    Yongfang XIE; Weihua GUI; Zhaohui JIANG

    2006-01-01

    For a class of value-bounded uncertain descriptor large-scale interconnected systems, the decentralized robust H∞ descriptor output feedback control problem is investigated. A design method based on the bounded real lemma is developed for a decentralized descriptor dynamic output feedback controller, which is reduced to a feasibility problem for a nonlinear matrix inequality (NLMI). It is proposed to solve the NLMI iteratively by the idea of homotopy, where some of the variables are fixed alternately at each iteration to reduce the NLMI to a linear matrix inequality (LMI). A given example shows the efficiency of this method

  7. Systemic Management of Schools: The OECD's Professionalisation and Dissemination of Output Governance in the 1960s

    Science.gov (United States)

    Bürgi, Regula

    2016-01-01

    At present, European education policy, research and administration is dominated by a specific concept of reform, namely so-called output governance, whose rise to prominence in national contexts in the 1990s coincided with the advance of international tests of school performance such as PISA. In this article it is argued that there is much more to…

  8. A multiprocessor system for the analysis of cardiac arrhythmias

    International Nuclear Information System (INIS)

    The study presented here forms part of a real-time electrocardiographic signal analysis system project. The medical data analysis system consists of eight independent analyser units, all of which are connected to a controller unit by the standard IEEE-488 bus. Each bed is monitored by an arrhythmias analyser which has the facilities for analysing a patient's electrocardiogram automatically in real time. The measurements may be made in the presence of a pacemaker. The system described presents the technique of a separate and a simultaneous data analysis on two different ECG channels. This permit: a better diagnosis and an optimum use of the bus. (author)

  9. Multiple-input multiple-output synthetic aperture ladar system for wide-range swath with high azimuth resolution.

    Science.gov (United States)

    Tang, Yu; Qin, Bao; Yan, Yun; Xing, Mengdao

    2016-02-20

    For the trade-off between the high azimuth resolution and the wide-range swath in the single-input single-output synthetic aperture ladar (SAL) system, the range swath of the SAL system is restricted to a narrow range, this paper proposes a multiple-input multiple-output (MIMO) synthetic aperture ladar system. The MIMO system adopts a low pulse repetition frequency (PRF) to avoid a range ambiguity for the wide-range swath and in azimuth adopts the multi-channel method to achieve azimuth high resolution from the unambiguous azimuth wide-spectrum signal, processed through adaptive digital beam-forming technology. Simulations and analytical results are presented. PMID:26906593

  10. Adaptive changes of the cardiac opioid system due to volume induced heart failure

    OpenAIRE

    Dehe, Lukas

    2016-01-01

    Knowledge about changes in the cardiac opioid system in congestive heart failure (CHF) is scarce. As such, this project investigated the cellular localization of the opioid receptors δ (DOR) and κ (KOR) in left ventricular (LV) myocardium. Opioid receptor (OR) binding sites were detected by radioligand binding. In addition, DOR and KOR localization was determined by double immunofluorescence confocal analysis in the left ventricle of male Wistar rats. DOR and KOR were colocalized with L-type ...

  11. Imaging of the atria and cardiac conduction system – from experiment to computer modelling

    OpenAIRE

    Hao, Guoliang

    2013-01-01

    Background: Experimental mapping and computer modelling provide important platforms to study the fundamental mechanisms underlying normal and abnormal activation of the heart. However, accurate computer modelling requires detailed anatomical models and needs support and validation from experimental data. Aims: 1) Construction of detailed anatomical heart models with the cardiac conduction system (CCS). 2) Mapping of the electrical activation sequence in rabbit atria to support and validate co...

  12. Physiological consequences of ionic concentration changes in cardiac cell tubular system

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Christé, G.; Šimurda, J.

    Plzeň : Západočeká universita v Plzni, 2004 - (Horák, M.), s. 1-4 ISBN 80-7043-315-9. [Biomechanics of Man 2004. hotel Horizont, Šumava (CZ), 16.11.2004-19.11.2004] R&D Projects: GA ČR GP204/02/D129 Institutional research plan: CEZ:AV0Z2076919 Keywords : cardiac cell * tubular system * quantitative modelling Subject RIV: BO - Biophysics

  13. Elevated Cardiac Troponins in Setting of Systemic Inflammatory Response Syndrome, Sepsis, and Septic Shock

    OpenAIRE

    Nasir Hussain

    2013-01-01

    Elevation of cardiac troponins and creatinine kinase is frequently observed in setting of systemic inflammatory response syndrome (SIRS), sepsis, or septic shock. Underlying pathophysiologic mechanism for such troponin leak, its clinical significance, and what different could be done in such settings remain elusive. In this paper we have briefly overviewed the proposed pathogenic mechanisms for SIRS, sepsis, or septic shock-related troponin elevation (SRTE) and have provided brief overview on...

  14. Basic Relations Type of System Dynamics DELAY_N Input-Output Under the Discrete State and Its Application

    Institute of Scientific and Technical Information of China (English)

    WeiyuanTu

    2004-01-01

    DELAY_N is a kind of important function in system dynamic. Studies about the basic relational type between its input and output under the discrete state have the significant influence and instruction in determination system dynamics model parameter, in debugging model, and in analyzing result. The article has obtained the DELAY_N inputoutput relational expressions, has obtained the input average delay time and the delay variance expression, in this foundution, proposed one method of determination delay functiontype.

  15. Real-time prediction models for output power and efficiency of grid-connected solar photovoltaic systems

    International Nuclear Information System (INIS)

    Highlights: ► We develop online prediction models for solar photovoltaic system performance. ► The proposed prediction models are simple but with reasonable accuracy. ► The maximum monthly average minutely efficiency varies 10.81–12.63%. ► The average efficiency tends to be slightly higher in winter months. - Abstract: This paper develops new real time prediction models for output power and energy efficiency of solar photovoltaic (PV) systems. These models were validated using measured data of a grid-connected solar PV system in Macau. Both time frames based on yearly average and monthly average are considered. It is shown that the prediction model for the yearly/monthly average of the minutely output power fits the measured data very well with high value of R2. The online prediction model for system efficiency is based on the ratio of the predicted output power to the predicted solar irradiance. This ratio model is shown to be able to fit the intermediate phase (9 am to 4 pm) very well but not accurate for the growth and decay phases where the system efficiency is near zero. However, it can still serve as a useful purpose for practitioners as most PV systems work in the most efficient manner over this period. It is shown that the maximum monthly average minutely efficiency varies over a small range of 10.81% to 12.63% in different months with slightly higher efficiency in winter months.

  16. Cardiac contractility, central haemodynamics and blood pressure regulation during semistarvation

    DEFF Research Database (Denmark)

    Stokholm, K H; Breum, L; Astrup, A

    1991-01-01

    pressure (BP) declined. The fall in BP was caused by the reduction in cardiac output as the total peripheral resistance was unchanged. Finally, the decline in total blood volume was not significant. These findings together with a reduction in heart rate indicated that a reduced sympathetic tone via......Eight obese patients were studied before and after 2 weeks of treatment by a very-low-calorie diet (VLCD). Cardiac output and central blood volume (pulmonary blood volume and left atrial volume) were determined by indicator dilution (125I-albumin) and radionuclide angiocardiography (first pass and...... equilibrium technique by [99Tcm]red blood cells). Cardiac output decreased concomitantly with the reduction in oxygen uptake as the calculated systemic arteriovenous difference of oxygen was unaltered. There were no significant decreases in left ventricular contractility indices, i.e. the ejection fraction...

  17. Money, output and the payment system: Optimal monetary policy in a model with hidden effort

    OpenAIRE

    Haslag, Joseph H; Joydeep Bhattacharya; Antoine Martin

    2007-01-01

    We propose a new explanation for the observed difference in the cost of intraday and overnight liquidity. We argue that the low cost of intraday liquidity is an application of the Friedman rule in an environment where a deviation of the Friedman rule is optimal with respect to overnight liquidity. In our environment the cost of overnight liquidity affects output while the cost of intraday liquidity only redistributes resources between money holders and non-money holders. We show that it is op...

  18. Fuzzy Controller for Matrix Converter System to Improve Its Quality of Output

    OpenAIRE

    N.Mahendran; Dr.G.Gurusamy

    2010-01-01

    In this paper, Fuzzy Logic controller is developed for ac/ac Matrix Converter. Furthermore, Total Harmonic Distortion is reduced significantly. Space Vector Algorithm is a method to improve power quality of the converter output. But its quality is limited to 86.7%.We are introduced a Cross coupled DQ axis controller to improve power quality. The Matrix Converter is an attractive topology for High voltage transformation ratio. A Matlab / Simulink simulation analysis of the Matrix C...

  19. Intelligent Cardiac Monitoring System using Virtual Instrumentation Techniques

    Directory of Open Access Journals (Sweden)

    Sharva Kant

    2011-07-01

    Full Text Available This paper describes the design of a portable, cheap and easy to handle microcontroller-based heart monitoring system using a Atmega32 model-based microcontroller and GLCD. The project is capable of detecting and distinguishing the normal heart signal from an abnormal one. A circuit was designed to convert the sound signals from the heart into electrical signals. The signal so obtained was then processed and conditioned to get a Phonocardiogram (PCG. The design considerations of this project are influenced by its target users. Its major application lies with medical practitioners in remote areas and army units in warzones where technical help is usually difficult. This project will facilitate a PCG read in such areas resulting in preventive timely measures being taken. This paper also gives solution to display the graphs and results on a GLCD which would further enhance the portability of this system.

  20. Cardiac echinococcosis

    Directory of Open Access Journals (Sweden)

    Ivanović-Krstić Branislava A.

    2002-01-01

    Full Text Available Cardiac hydatid disease is rare. We report on an uncommon hydatid cyst localized in the right ventricular wall, right atrial wall tricuspid valve left atrium and pericard. A 33-year-old woman was treated for cough, fever and chest pain. Cardiac echocardiograpic examination revealed a round tumor (5.8 x 4 cm in the right ventricular free wall and two smaller cysts behind that tumor. There were cysts in right atrial wall and tricuspidal valve as well. Serologic tests for hydatidosis were positive. Computed tomography finding was consistent with diagnosis of hydatid cyst in lungs and right hylar part. Surgical treatment was rejected due to great risk of cardiac perforation. Medical treatment with albendazole was unsuccessful and the patient died due to systemic hydatid involvement of the lungs, liver and central nervous system.

  1. Effects of Aerobic Exercise Training on Cardiac Renin-Angiotensin System in an Obese Zucker Rat Strain

    OpenAIRE

    Diego Lopes Mendes Barretti; Flávio de Castro Magalhães; Tiago Fernandes; Everton Crivoi do Carmo; Kaleizu Teodoro Rosa; Maria Claudia Irigoyen; Carlos Eduardo Negrão; Edilamar Menezes Oliveira

    2012-01-01

    OBJECTIVE: Obesity and renin angiotensin system (RAS) hyperactivity are profoundly involved in cardiovascular diseases, however aerobic exercise training (EXT) can prevent obesity and cardiac RAS activation. The study hypothesis was to investigate whether obesity and its association with EXT alter the systemic and cardiac RAS components in an obese Zucker rat strain. METHODS: THE RATS WERE DIVIDED INTO THE FOLLOWING GROUPS: Lean Zucker rats (LZR); lean Zucker rats plus EXT (LZR+EXT); obese Zu...

  2. Design of satisfaction output feedback controls for stochastic nonlinear systems under quadratic tracking risk-sensitive index

    Institute of Scientific and Technical Information of China (English)

    刘允刚; 张纪峰; 潘子刚

    2003-01-01

    In this paper, the design problem of satisfaction output feedback controls for stochastic nonlinear systems in strict feedback form under long-term tracking risk-sensitive index is investigated.The index function adopted here is of quadratic form usually encountered in practice, rather than of quartic one used to beg the essential difficulty on controller design and performance analysis of the closed-loop systems. For any given risk-sensitive parameter and desired index value, by using the integrator backstepping method, an output feedback control is constructively designed so that the closed-loop system is bounded in probability and the risk-sensitive index is upper bounded by the desired value.

  3. MODELING OF THE PRIORITY SCHEDULING INPUT-LINE GROUP OUTPUT WITH MULTI-CHANNEL IN ATM EXCHANGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode (ATM) exchange system is proposed and then the mean method is used to model mathematically the non-typical non-anticipative PRiority service (PR) model. Compared with the typical and non-anticipative PR model, it expresses the characteristics of the priority scheduling input-line group output with multi-channel in ATM exchange system. The simulation experiment shows that this model can improve the HOL block and the performance of input-queued ATM switch network dramatically. This model has a better developing prospect in ATM exchange system.

  4. Blind decorrelation and deconvolution algorithm for multiple-input multiple-output system: II. Analysis and simulation

    Science.gov (United States)

    Chen, Da-Ching; Yu, Tommy; Yao, Kung; Pottie, Gregory J.

    1999-11-01

    For single-input multiple-output (SIMO) systems blind deconvolution based on second-order statistics has been shown promising given that the sources and channels meet certain assumptions. In our previous paper we extend the work to multiple-input multiple-output (MIMO) systems by introducing a blind deconvolution algorithm to remove all channel dispersion followed by a blind decorrelation algorithm to separate different sources from their instantaneous mixture. In this paper we first explore more details embedded in our algorithm. Then we present simulation results to show that our algorithm is applicable to MIMO systems excited by a broad class of signals such as speech, music and digitally modulated symbols.

  5. Maximum power output and load matching of a phosphoric acid fuel cell-thermoelectric generator hybrid system

    Science.gov (United States)

    Chen, Xiaohang; Wang, Yuan; Cai, Ling; Zhou, Yinghui

    2015-10-01

    Based on the current models of phosphoric acid fuel cells (PAFCs) and thermoelectric generators (TGs), a new hybrid system is proposed, in which the effects of multi-irreversibilities resulting from the activation, concentration, and ohmic overpotentials in the PAFC, Joule heat and heat leak in the TG, finite-rate heat transfer between the TG and the heat reservoirs, and heat leak from the PAFC to the environment are taken into account. Expressions for the power output and efficiency of the PAFC, TG, and hybrid system are analytically derived and directly used to discuss the performance characteristics of the hybrid system. The optimal relationship between the electric currents in the PAFC and TG is obtained. The maximum power output is numerically calculated. It is found that the maximum power output density of the hybrid system will increase about 150 Wm-2, compared with that of a single PAFC. The problem how to optimally match the load resistances of two subsystems is discussed. Some significant results for practical hybrid systems are obtained.

  6. Non-sedating antihistamine drugs and cardiac arrhythmias -- biased risk estimates from spontaneous reporting systems?

    DEFF Research Database (Denmark)

    De Bruin, M L; van Puijenbroek, E P; Egberts, A C G;

    2002-01-01

    AIMS: This study used spontaneous reports of adverse events to estimate the risk for developing cardiac arrhythmias due to the systemic use of non-sedating antihistamine drugs and compared the risk estimate before and after the regulatory action to recall the over-the-counter status of some of...... patients were using non-sedating antihistamines. In general non-sedating antihistamines are associated with cardiac arrhythmia to a higher extent in comparison with other drugs (ADR reporting odds ratio 2.05 [95% CI: 1.45, 2.89]). The association between arrhythmias and non-sedating antihistamine drugs...... calculated before 1998 was not significantly higher than 1 (OR 1.37 [95% CI: 0.85, 2.23]), whereas the risk estimate calculated after the governmental decision did significantly differ from 1 (OR 4.19 [95% CI: 2.49, 7.05]). CONCLUSIONS: Our data suggest that non-sedating antihistamines might have an...

  7. Effects of cardiac sympathetic nervous system on the stunned myocardium

    International Nuclear Information System (INIS)

    123I-Metaiodobenzylguanidine (123I-MIBG) uptake in the stunned myocardium was investigated in open chest dogs. 123I-MIBG is a tracer taken up in presynaptic adrenergic vesicles and reflects the function of the myocardial sympathetic nervous system. This study revealed that in the stunned myocardium without infarct, 123I-MIBG uptake was normal up to 40 minutes of ischemia and that exogenous noradrenaline improved deteriolated regional wall motion with increased uptake of 123I-MIBG. However, uptake of 123I-MIBG per flow decreased with infarct in ischemic areas, and it showed a linear relation with regional wall motion. Thus, in the absence of infarction 123I-MIBG is a tracer to differentiate stunning from more severe ischemia with persistent wall motion abnormality. Normal uptake and storage of 123I-MIBG in the stunned condition suggests that catecholamine release or second effector mechanism may relate to the mechanism. (author)

  8. Culturing Mouse Cardiac Valves in the Miniature Tissue Culture System.

    Science.gov (United States)

    Kruithof, Boudewijn P T; Lieber, Samuel C; Kruithof-de Julio, Marianna; Gaussin, Vincian; Goumans, Marie José

    2015-01-01

    Heart valve disease is a major burden in the Western world and no effective treatment is available. This is mainly due to a lack of knowledge of the molecular, cellular and mechanical mechanisms underlying the maintenance and/or loss of the valvular structure. Current models used to study valvular biology include in vitro cultures of valvular endothelial and interstitial cells. Although, in vitro culturing models provide both cellular and molecular mechanisms, the mechanisms involved in the 3D-organization of the valve remain unclear. While in vivo models have provided insight into the molecular mechanisms underlying valvular development, insight into adult valvular biology is still elusive. In order to be able to study the regulation of the valvular 3D-organization on tissue, cellular and molecular levels, we have developed the Miniature Tissue Culture System. In this ex vivo flow model the mitral or the aortic valve is cultured in its natural position in the heart. The natural configuration and composition of the leaflet are maintained allowing the most natural response of the valvular cells to stimuli. The valves remain viable and are responsive to changing environmental conditions. This MTCS may provide advantages on studying questions including but not limited to, how does the 3D organization affect valvular biology, what factors affect 3D organization of the valve, and which network of signaling pathways regulates the 3D organization of the valve. PMID:26555276

  9. Nonlinear disturbance observer-based control for multi-input multi-output nonlinear systems subject to mismatching condition

    Science.gov (United States)

    Yang, Jun; Li, Shihua; Chen, Wen-Hua

    2012-08-01

    For a multi-input multi-output (MIMO) nonlinear system, the existing disturbance observer-based control (DOBC) only provides solutions to those whose disturbance relative degree (DRD) is higher than or equal to its input relative degree. By designing a novel disturbance compensation gain matrix, a generalised nonlinear DOBC method is proposed in this article to solve the disturbance attenuation problem of the MIMO nonlinear system with arbitrary DRD. It is shown that the disturbances are able to be removed from the output channels by the proposed method with appropriately chosen control parameters. The property of nominal performance recovery, which is the major merit of the DOBCs, is retained with the proposed method. The feasibility and effectiveness of the proposed method are demonstrated by simulation studies of both the numerical and application examples.

  10. Decentralized Output Feedback Adaptive NN Tracking Control for Time-Delay Stochastic Nonlinear Systems With Prescribed Performance.

    Science.gov (United States)

    Hua, Changchun; Zhang, Liuliu; Guan, Xinping

    2015-11-01

    This paper studies the dynamic output feedback tracking control problem for stochastic interconnected time-delay systems with the prescribed performance. The subsystems are in the form of triangular structure. First, we design a reduced-order observer independent of time delay to estimate the unmeasured state variables online instead of the traditional full-order observer. Then, a new state transformation is proposed in consideration of the prescribed performance requirement. Using neural network to approximate the composite unknown nonlinear function, the corresponding decentralized output tracking controller is designed. It is strictly proved that the resulting closed-loop system is stable in probability in the sense of uniformly ultimately boundedness and that both transient-state and steady-state performances are preserved. Finally, a simulation example is given, and the result shows the effectiveness of the proposed control design method. PMID:25794398

  11. Cardiac sarcoidosis

    Science.gov (United States)

    Smedema, J.P.; Zondervan, P.E.; van Hagen, P.; ten Cate, F.J.; Bresser, P.; Doubell, A.F.; Pattynama, P.; Hoogsteden, H.C.; Balk, A.H.M.M.

    2002-01-01

    Sarcoidosis is a multi-system granulomatous disorder of unknown aetiology. Symptomatic cardiac involvement occurs in approximately 5% of patients. The prevalence of sarcoidosis in the Netherlands is unknown, but estimated to be approximately 20 per 100,000 population (3200 patients). We report on five patients who presented with different manifestations of cardiac sarcoidosis, and give a brief review on the current management of this condition. Magnetic Resonance Imaging (MRI) can be of great help in diagnosing this condition as well as in the follow-up of the response to therapy. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6 PMID:25696121

  12. An on-line data acquisition system of oscilloscope-embedded input/output controller for cavity BPM measurement

    International Nuclear Information System (INIS)

    Cavity beam position monitor (BPM) is widely used in a precise electron beam position measurement. Based on high performance oscilloscope-embedded EPICS input/output controller, we developed an on-line cavity BPM signal processing system for fast data acquisition solution when designing a cavity BPM. Also, methods for extracting the position information from cavity pickup signals and calibration algorithm are included in this solution. (authors)

  13. Adaptive observers-based synchronization of a class of Lur'e systems with delayed outputs for chaotic communications

    OpenAIRE

    Dimassi, Habib; Loria, Antonio; Belghith, Safya

    2012-01-01

    In this paper, we propose an adaptive observer-based synchronization approach for a class of chaotic Lur'e systems with slope restricted nonlinearities and delayed outputs. The delay is assumed bounded and time varying and the information to be transmitted is assumed piece-wise constant. Based on the Lyapunov-Krasovskii approach, we show that for sufficiently small values of the time-delay upper bound, both synchronization and information reconstruction objectives are ensured under a conditio...

  14. Evaluation of the acute cardiac and central nervous system effects of the fluorocarbon trifluoromethane in baboons

    Energy Technology Data Exchange (ETDEWEB)

    Branch, C.A.; Goldberg, D.A.; Ewing, J.R.; Butt, S.S.; Gayner, J. [Henry Ford Hospital, Detroit, MI (United States); Fagan, S.C. [Wayne State Univ., Detroit, MI (United States)

    1994-12-31

    The gaseous fluorocarbon trifluoromethane has recently been investigated for its potential as an in vivo gaseous indicator for nuclear magnetic resonance studies of brain perfusion. Trifluoromethane may also have significant value as a replacement for chlorofluorocarbon fire retardants. Because of possible species-specific cardiotoxic and anesthetic properties, the toxicological evaluation of trifluoromethane in primates (Papio anubis) is necessary prior to its evaluation in humans. We report the acute cardiac and central nervous system effects of trifluoromethane in eight anesthetized baboons. A dose-response effect was established for respiratory rate, electroencephalogram, and cardiac sinus rate, which exhibited a stepwise decrease from 10% trifluoromethane. No spontaneous arrhythmias were noted, and arterial blood pressure remained unchanged at any inspired level. Intravenous epinephrine infusions (1 {mu}g/kg) induced transient cardiac arrhythmia in 1 animal only at 70% FC-23 (v/v) trifluoromethane. Trifluoromethane appears to induce mild dose-related physiological changes at inspired levels of 30% or more, indicative of an anesthetic effect. These data suggest that trifluoromethane may be safe to use in humans, without significant adverse acute effects, at an inspired level of 30%. 23 refs., 3 figs., 3 tabs.

  15. An interoperable system for automated diagnosis of cardiac abnormalities from electrocardiogram data.

    Science.gov (United States)

    Tinnakornsrisuphap, Thidarat; Billo, Richard E

    2015-03-01

    Electrocardiogram (ECG) data are stored and analyzed in different formats, devices, and computer platforms. As a result, ECG data from different monitoring devices cannot be displayed unless the user has access to the proprietary software of each particular device. This research describes an ontology and encoding for representation of ECG data that allows open exchange and display of ECG data in a web browser. The ontology is based on the Health Level Seven (HL7) medical device communication standard. It integrates ECG waveform data, HL7 standard ECG data descriptions, and cardiac diagnosis rules, providing a capability to both represent ECG waveforms as well as perform automated diagnosis of 37 different cardiac abnormalities. The ECG ontology is encoded in XML, thus allowing ECG data from any digital ECG device that maps to it to be displayed in a general-purpose Internet browser. An experiment was conducted to test the interoperability of the system (ability to openly share ECG data without error in a web browser) and also to assess the accuracy of the diagnosis model. Results showed 100% interoperability using 276 ECG data files and 93% accuracy in diagnosis of abnormal cardiac conditions. PMID:24808416

  16. Sympathoadrenal and hypophyseal-adrenal systems in preoperative irradiation of patients with esophageal and cardiac cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tarutinov, V.I.; Starosel' skij, I.V.; Gol' dshmidt, B.Ya.; Shmal' ko, Yu.P.; Levchenko, A.M. (Nauchno-Issledovatel' skij Rentgeno-Radiologicheskij i Onkologicheskij Inst., Kiev (Ukrainian SSR))

    1983-11-01

    A study was made of 74 patients with esophageal and cardiac cancer, Stages 3 and 4. The excretion of catecholamines, corticosteroids and their precursors was studied, tests with adrenalin before and after preoperative irradiation at a summary dose of 30 Gy were done. It has been shown that before the start of radiation therapy the excretion of catecholamines and corticosteroids is lowered, the reaction to adrenalin administration is negative in most patients, the phase syndrome of cardiac hypodynamics associated with disturbed function of the sympathoadrenal system was revealed. Preoperative irradiation in patients with esophageal and cardiac cancer results in an increased excretion of 17-ketosteroids (17-KS) and 17-ketogenic steroids, however 17-KS excretion does not reach the normal level. For better tolerance of irradiation and for a radiosensitization effect testenate is administered to patients before and during radiation therapy. The administration of testenate 7-10 days before the start and during radiotherapy proved to be effective which was confirmed by noticeable necrobiotic and necrotic changes of cancer cells.

  17. H∞ Output Feedback Control for Stochastic Systems with Mode-dependent Time-varying Delays and Markovian Jump Parameters

    Institute of Scientific and Technical Information of China (English)

    Xu-Dong Zhao; Qing-Shuang Zeng

    2010-01-01

    This paper deals with the H∞ control problems of Markovian jump systems with mode-dependent time delays. First, considering the mode-dependent time delays, a different delay-dependent H∞ performance condition for Markovian jump systems isproposed by constructing an improved Lyapunov-Krasovskii function. Based on this new H∞ disturbance attenuation criterion, a full-order dynamic output feedback controller that ensures the exponential mean-square stability and a prescribed H∞ performance level for the resulting closed-loop system is designed. Illustrative numerical examples are provided to demonstrate the effectiveness of the proposed approach.

  18. Neural Network Compensation Control for Output Power Optimization of Wind Energy Conversion System Based on Data-Driven Control

    OpenAIRE

    Li, T.; Feng, A. J.; Zhao, L.

    2012-01-01

    Due to the uncertainty of wind and because wind energy conversion systems (WECSs) have strong nonlinear characteristics, accurate model of the WECS is difficult to be built. To solve this problem, data-driven control technology is selected and data-driven controller for the WECS is designed based on the Markov model. The neural networks are designed to optimize the output of the system based on the data-driven control system model. In order to improve the efficiency of the neural network trai...

  19. Final report on testing of TOPAZ II unit Ya-21u: Output power characteristics and system capabilities

    International Nuclear Information System (INIS)

    A final report on the output power characteristics and capabilities of the TOPAZ II Space Nuclear Power Unit Ya-21u is presented. Results showed that after a total of almost 8,000 hours of system testing in the U.S. and Russia, several emergency cooldowns, and three inadvertent air introductions to the interelectrode gap (IEG) that the TOPAZ II demonstrates the potential for providing reliable power in a space environment. Output power optimizations and system characteristics following a shock and vibration test are shown. These tests were performed using electrical heaters that simulate nuclear fuel heating. This paper will focus primarily on the changes in output power characteristics over the lifetime of Ya-21u. All U.S. testing was conducted at the Thermionic System Evaluation Test (TSET) Facility of the New Mexico Engineering Research Institute (NMERI) as a part of the TOPAZ International Program (TIP). TIP is managed by the Air Force Phillips Laboratory (PL) for the Ballistic Missile Defense Organization (BMDO). copyright 1996 American Institute of Physics

  20. Boolean modeling of neural systems with point-process inputs and outputs. Part I: theory and simulations.

    Science.gov (United States)

    Marmarelis, Vasilis Z; Zanos, Theodoros P; Berger, Theodore W

    2009-08-01

    This paper presents a new modeling approach for neural systems with point-process (spike) inputs and outputs that utilizes Boolean operators (i.e. modulo 2 multiplication and addition that correspond to the logical AND and OR operations respectively, as well as the AND_NOT logical operation representing inhibitory effects). The form of the employed mathematical models is akin to a "Boolean-Volterra" model that contains the product terms of all relevant input lags in a hierarchical order, where terms of order higher than first represent nonlinear interactions among the various lagged values of each input point-process or among lagged values of various inputs (if multiple inputs exist) as they reflect on the output. The coefficients of this Boolean-Volterra model are also binary variables that indicate the presence or absence of the respective term in each specific model/system. Simulations are used to explore the properties of such models and the feasibility of their accurate estimation from short data-records in the presence of noise (i.e. spurious spikes). The results demonstrate the feasibility of obtaining reliable estimates of such models, with excitatory and inhibitory terms, in the presence of considerable noise (spurious spikes) in the outputs and/or the inputs in a computationally efficient manner. A pilot application of this approach to an actual neural system is presented in the companion paper (Part II). PMID:19517238

  1. Procalcitonin for the differential diagnosis of infectious and non-infectious systemic inflammatory response syndrome after cardiac surgery

    OpenAIRE

    Zhao, Dong; Zhou, Jianxin; Haraguchi, Go; Arai, Hirokuni; Mitaka, Chieko

    2014-01-01

    Background This study was performed to assess the value of procalcitonin (PCT) for the differential diagnosis between infectious and non-infectious systemic inflammatory response syndrome (SIRS) after cardiac surgery. Methods Patients diagnosed with SIRS after cardiac surgery between April 1, 2011 and March 31, 2013 were retrospectively studied. A total of 142 patients with SIRS, infectious (n = 47) or non-infectious (n = 95), were included. The patients with infectious SIRS included 11 with ...

  2. Ultra-fast consensus of discrete-time multi-agent systems with multi-step predictive output feedback

    Science.gov (United States)

    Zhang, Wenle; Liu, Jianchang

    2016-04-01

    This article addresses the ultra-fast consensus problem of high-order discrete-time multi-agent systems based on a unified consensus framework. A novel multi-step predictive output mechanism is proposed under a directed communication topology containing a spanning tree. By predicting the outputs of a network several steps ahead and adding this information into the consensus protocol, it is shown that the asymptotic convergence factor is improved by a power of q + 1 compared to the routine consensus. The difficult problem of selecting the optimal control gain is solved well by introducing a variable called convergence step. In addition, the ultra-fast formation achievement is studied on the basis of this new consensus protocol. Finally, the ultra-fast consensus with respect to a reference model and robust consensus is discussed. Some simulations are performed to illustrate the effectiveness of the theoretical results.

  3. Earth observing system. Output data products and input requirements, version 2.0. Volume 2: Analysis of IDS input requirements

    Science.gov (United States)

    Lu, Yun-Chi; Chang, Hyo Duck; Krupp, Brian; Kumar, Ravindra; Swaroop, Anand

    1992-01-01

    On 18 Jan. 1991, NASA confirmed 29 Inter-Disciplinary Science (IDS) teams, each involving a group of investigators, to conduct interdisciplinary research using data products from Earth Observing System (EOS) instruments. These studies are multi-disciplinary and require output data products from multiple EOS instruments, including both FI and PI instruments. The purpose of this volume is to provide information on output products expected from IDS investigators, required input data, and retrieval algorithms. Also included in this volume is the revised analysis of the 'best' and 'alternative' match data products for IDS input requirements. The original analysis presented in the August 1991 release of the SPSO Report was revised to incorporate the restructuring of the EOS platform. As a result of the reduced EOS payload, some of EOS instruments were deselected and their data products would not be available for IDS research. Information on these data products is also presented.

  4. Design and Implementation of an Integrated Fuzzy Logic Controller for a Multi-input Multi-output System

    Directory of Open Access Journals (Sweden)

    S.S. Patil

    2011-05-01

    Full Text Available The design and real time implementation of an integrated fuzzy logic controller (IFLC for a multipleinput multiple-output (MIMO system is presented. The design of IFLC for an uncoupled MIMO system has been discussed. This study develops a combination of fuzzy and PID controllers (PIDC to improve the control performance of a two-input-two-output (TITO: angular position, and rotational speed system. These parameters play a vital role in radar-tracking system for military applications. To verify the applicability of proposed controller, two-motor unit plant along with indigenously designed multi-channel analog interface board of 16-bit precision is used. The proposed MIMO control system is interfaced to a PC through its parallel port. The performance of the system is studied by subjecting it to various standard test signals. The IFLC performs better than the other two controllers in tracking the input command for linear as well as nonlinear inputs such as step, square, triangular, and sine waves is observed.

  5. Observer-based H-infinity output feedback control with feedback gain and observer gain variations for Delta operator system

    Institute of Scientific and Technical Information of China (English)

    Ruiquan LIN; Fuwen YANG; Renchong PENG

    2009-01-01

    Considering that the controller feedback gain and the observer gain are of additive norm-bounded variations, a design method of observer-based H-infinity output feedback controller for uncertain Delta operator systems is proposed in this paper. A sufficient condition of such controllers is presented in linear matrix inequality (LMI) forms. A numerical example is then given to illustrate the effectiveness of this method, that is, the obtained controller guarantees the closed-loop system asymptotically stable and the expected H-infinity performance even if the controller feedback gain and the observer gain are varied.

  6. Complex Nonlinear Autonomic Nervous System Modulation Link Cardiac Autonomic Neuropathy and Peripheral Vascular Disease

    Directory of Open Access Journals (Sweden)

    Kinda eKhalaf

    2015-03-01

    Full Text Available Background: Physiological interactions are abundant within, and between, body systems. These interactions may evolve into discrete states during pathophysiological processes resulting from common mechanisms. An association between arterial stenosis, identified by low ankle-brachial pressure index (ABPI and cardiovascular disease (CVD as been reported. Whether an association between vascular calcification - characterized by high ABPI and a different pathophysiology - is similarly associated with CVD, has not been established. The current study aims to investigate the association between ABPI, and cardiac rhythm, as an indicator of cardiovascular health and functionality, utilising heart rate variability (HRV.Methods and Results: Two hundred and thirty six patients underwent ABPI assessment. Standard time and frequency domain, and non-linear HRV measures were determined from 5-minute electrocardiogram. ABPI data were divided into normal (n=101, low (n=67 and high (n=66 and compared to HRV measures.(DFAα1 and SampEn were significantly different between the low ABPI, high ABPI and control groups (p<0.05.Conclusion: A possible coupling between arterial stenosis and vascular calcification with decreased and increased HRV respectively was observed. Our results suggest a model for interpreting the relationship between vascular pathophysiology and cardiac rhythm. The cardiovascular system may be viewed as a complex system comprising a number of interacting subsystems. These cardiac and vascular subsystems/networks may be coupled and undergo transitions in response to internal or external perturbations. From a clinical perspective, the significantly increased sample entropy compared to the normal ABPI group and the decreased and increased complex correlation properties measured by DFA for the low and high ABPI groups respectively, may be useful indicators that a more holistic treatment approach in line with this more complex clinical picture is required.

  7. Development Output Program Data Entry System For RSG-GAS Application

    International Nuclear Information System (INIS)

    Data Entry System is a data acquisition software of failure data of system and component. The acquisition data was calculated to get the failure rate, upper bound value. Since the calculated is big enough the development on Data Entry System program was introduced. Now, the data Entry System can be run to calculate big enough data

  8. The power output and efficiency of a negative capacitance shunt for vibration control of a flexural system

    International Nuclear Information System (INIS)

    A negative capacitance shunt is a basic, analog, active circuit electrically connected to a piezoelectric transducer to control the vibrations of flexural bodies. The shunt circuit consists of a resistor and a synthetic negative capacitor to introduce a real and imaginary impedance on a vibrating mechanical system. The electrical impedance of the negative capacitance shunt modifies the effective modulus of the piezoelectric transducer to reduce the stiffness and increase the damping, which causes a decrease in amplitude of the vibrating structure to which the elements are bonded. To gain an insight into the electromechanical coupling and power output, the shunt and the electrical properties of the piezoelectric transducer are modeled using circuit modeling software. The power output of the model is validated with experimental measurements of a shunt connected to a piezoelectric transducer pair bonded to a vibrating aluminum cantilever beam. The model is used to select the passive components of the negative capacitance shunt to increase the efficiency and quantify the voltage output limit of the op-amp. (paper)

  9. Note: An improved calibration system with phase correction for electronic transformers with digital output

    International Nuclear Information System (INIS)

    The existing electronic transformer calibration systems employing data acquisition cards cannot satisfy some practical applications, because the calibration systems have phase measurement errors when they work in the mode of receiving external synchronization signals. This paper proposes an improved calibration system scheme with phase correction to improve the phase measurement accuracy. We employ NI PCI-4474 to design a calibration system, and the system has the potential to receive external synchronization signals and reach extremely high accuracy classes. Accuracy verification has been carried out in the China Electric Power Research Institute, and results demonstrate that the system surpasses the accuracy class 0.05. Furthermore, this system has been used to test the harmonics measurement accuracy of all-fiber optical current transformers. In the same process, we have used an existing calibration system, and a comparison of the test results is presented. The system after improvement is suitable for the intended applications

  10. Note: An improved calibration system with phase correction for electronic transformers with digital output

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Han-miao, E-mail: chenghanmiao@hust.edu.cn; Li, Hong-bin, E-mail: lihongbin@hust.edu.cn [CEEE of Huazhong University of Science and Technology, Wuhan 430074 (China); State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Wuhan 430074 (China)

    2015-08-15

    The existing electronic transformer calibration systems employing data acquisition cards cannot satisfy some practical applications, because the calibration systems have phase measurement errors when they work in the mode of receiving external synchronization signals. This paper proposes an improved calibration system scheme with phase correction to improve the phase measurement accuracy. We employ NI PCI-4474 to design a calibration system, and the system has the potential to receive external synchronization signals and reach extremely high accuracy classes. Accuracy verification has been carried out in the China Electric Power Research Institute, and results demonstrate that the system surpasses the accuracy class 0.05. Furthermore, this system has been used to test the harmonics measurement accuracy of all-fiber optical current transformers. In the same process, we have used an existing calibration system, and a comparison of the test results is presented. The system after improvement is suitable for the intended applications.

  11. Note: An improved calibration system with phase correction for electronic transformers with digital output.

    Science.gov (United States)

    Cheng, Han-miao; Li, Hong-bin

    2015-08-01

    The existing electronic transformer calibration systems employing data acquisition cards cannot satisfy some practical applications, because the calibration systems have phase measurement errors when they work in the mode of receiving external synchronization signals. This paper proposes an improved calibration system scheme with phase correction to improve the phase measurement accuracy. We employ NI PCI-4474 to design a calibration system, and the system has the potential to receive external synchronization signals and reach extremely high accuracy classes. Accuracy verification has been carried out in the China Electric Power Research Institute, and results demonstrate that the system surpasses the accuracy class 0.05. Furthermore, this system has been used to test the harmonics measurement accuracy of all-fiber optical current transformers. In the same process, we have used an existing calibration system, and a comparison of the test results is presented. The system after improvement is suitable for the intended applications. PMID:26329248

  12. Development of technical requirements on the in-reactor control system (SVRK) in WWER reactor with medium output power

    International Nuclear Information System (INIS)

    General concepts of in-reactor control in WWER reactors with medium output power and development of requirements on in-reactor control starting with the first generation of WWER-440 up WWER-640 with regard to the assurance of monitoring core conditions are dealt within the paper. The basis of WWER in-reactor control is provided by in-reactor sensors distributed in a stationary pattern (thermocouples for control of coolant temperature at assembly exits and sensors of local energy generation of self-powered detectors of SPD type). A new generation of WWER reactors with medium output is planned to operate both in basic load mode, as well as in maneuverability mode and SVRK systems in WWER-640 thus have to ensure the implementation of the following new requirements:generation of control signals for local core parameters;complex diagnostics of core conditions;prognosis of core characteristics. The new requirements on in-core control system (including class B from IEC 1226) need also a modernization and development of basic elements including in-reactor sensors for coolant temperature control. Issues and experience from in-core control system modernization at existing WWER reactors are also analyzed in the paper. While modernizing the existing WWER in relation to the use of new fuel cycles, up rating of thermal output and maneuverability of power units, it is advisable to perform a complete modernization and assure a possibility for phased implementation of current technical requirements on the in-core control system and on its basic elements. (Authors)

  13. Study on an optimum ratio of PV output energy to WG output energy in PV/WG hybrid system; Taiyoko/furyoku hybrid hatsuden system no saiteki yoryohi ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, S. [Kandenko Co. Ltd., Tokyo (Japan)

    1996-10-27

    A photovoltaic power (PV) and wind generated power (WG) are an unlimited clean energy source, yet their output is unstable depending on the fluctuation of weather conditions such as solar radiation and wind velocity. Consequently, a large-scale power storage equipment is necessitated leading to a high cost especially in an independent system. As a solution, a method is available in which PV and WG are combined so that the effect may be utilized for stabilizing the output of a system as a whole, at a site where a fluctuation pattern is different between photovoltaic energy and wind energy. In building a hybrid system by PV and WG, sites with such supplementary effect existing were selected from the viewpoint of stabilizing the fluctuation of the power generation in the long run; and then, an examination was made on the optimum PV capacity ratio (%Ppo) in each site. As a result, it revealed that the %Ppo had great bearing on a ratio of PV energy fluctuation to WG, which was converted to a numerical formula. A comparatively simple examination by means of meteorological data also indicated that the share ratio was possibly optimized between the quantities of PV and WG energy. 4 refs., 2 figs., 2 tabs.

  14. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    Science.gov (United States)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  15. Estimación del gasto cardíaco: Utilidad en la práctica clínica. Monitorización disponible invasiva y no invasiva Estimating cardiac output: Utility in the clinical practice. Available invasive and non-invasive monitoring

    Directory of Open Access Journals (Sweden)

    X. García

    2011-12-01

    Full Text Available Esta revisión pretende profundizar en el conocimiento del gasto cardíaco, sus variables y sus condicionantes, así como repasar exhaustivamente las diferentes técnicas disponibles para su monitorización y establecer las situaciones en que el conocimiento del gasto cardíaco nos aporta una información fundamental en el manejo del paciente crítico. La técnica de Fick, utilizada en los inicios para calcular el gasto cardíaco de los pacientes, ha sido sustituida hoy en día en la práctica clínica por los métodos de termodilución (transcardíaca o transpulmonar, litiodilución, biorreactancia, la tecnología basada en el efecto Doppler o la ecocardiografía. El análisis de la onda de pulso ha permitido la obtención de una medida continua y mínimamente invasiva del gasto cardíaco. Otros métodos, como la biorrectancia, el Doppler o la ecocardiografía nos permiten, en la actualidad, obtener medidas del gasto cardíaco de forma no invasiva, rápida y fiable.This aim of this review is to provide a detailed review of the physiologic conditions and variables of the cardiac output, as well as review the different techniques available for its measurement. We also want to establish the clinical situations in which the measurement of cardiac output can add valuable information for the management of critically ill patients. The Fick technique, used in the beginning to calculate cardiac output, has been replaced today by thermodilution techniques (transcardiac or transpulmonary, lithium dilution, bioreactance, Doppler technique or echocardiography. Pulse wave analysis allows a continuous minimally invasive cardiac output measurement. Other methods, such bioreactance, Doppler technique or echocardiography currently provide a valid, fast and non-invasive measurement of cardiac output.

  16. Protection study of a diagnostic system for electron beam at the output of an accelerator

    International Nuclear Information System (INIS)

    The aim of this work is the determination of the conception of a protection system dedicated to protect a diagnostic system in the CNSTN. According to this study, the suitable material for the protection against the electrons in the plexiglas and the supermalloy to protect the future diagnostic system against the magnetic field. (Author)

  17. A Wearable Contactless Sensor Suitable for Continuous Simultaneous Monitoring of Respiration and Cardiac Activity

    OpenAIRE

    Gargiulo, Gaetano D; Upul Gunawardana; Aiden O’Loughlin; Mohammad Sadozai; Elham Shabani Varaki; Breen, Paul P.

    2015-01-01

    A reliable system that can simultaneously and accurately monitor respiration and cardiac output would have great utility in healthcare applications. In this paper we present a novel approach to creating such a system. This noninvasive, low power, low cost, contactless sensor is suitable for continuous monitoring of respiration (tidal volume) and cardiac stroke volume. Furthermore, it is capable of delivering this data in true volume (i.e., mL). The current embodiment, specifically designed fo...

  18. Monitoring of multiple loads in wireless power transfer systems without direct output feedback

    OpenAIRE

    J. Yin; Lin, D.; Lee, CK; Hui, RSY

    2014-01-01

    In this paper, a computational method that uses only the input voltage and current to identify the impedances of multiple loads in wireless power transfer systems without any direct load measurements is proposed. The method has been practically realized in a wireless power domino-resonator system comprising 8 resonators. A good degree of accuracy has been achieved in the practical verification. Although the method is demonstrated in a relatively complex system, the principle applies to any wi...

  19. Imaging system for cardiac planar imaging using a dedicated dual-head gamma camera

    Science.gov (United States)

    Majewski, Stanislaw; Umeno, Marc M.

    2011-09-13

    A cardiac imaging system employing dual gamma imaging heads co-registered with one another to provide two dynamic simultaneous views of the heart sector of a patient torso. A first gamma imaging head is positioned in a first orientation with respect to the heart sector and a second gamma imaging head is positioned in a second orientation with respect to the heart sector. An adjustment arrangement is capable of adjusting the distance between the separate imaging heads and the angle between the heads. With the angle between the imaging heads set to 180 degrees and operating in a range of 140-159 keV and at a rate of up to 500kHz, the imaging heads are co-registered to produce simultaneous dynamic recording of two stereotactic views of the heart. The use of co-registered imaging heads maximizes the uniformity of detection sensitivity of blood flow in and around the heart over the whole heart volume and minimizes radiation absorption effects. A normalization/image fusion technique is implemented pixel-by-corresponding pixel to increase signal for any cardiac region viewed in two images obtained from the two opposed detector heads for the same time bin. The imaging system is capable of producing enhanced first pass studies, bloodpool studies including planar, gated and non-gated EKG studies, planar EKG perfusion studies, and planar hot spot imaging.

  20. Myocyte-fibroblast communication in cardiac fibrosis and arrhythmias: Mechanisms and model systems.

    Science.gov (United States)

    Pellman, Jason; Zhang, Jing; Sheikh, Farah

    2016-05-01

    Development of cardiac fibrosis and arrhythmias is controlled by the activity of and communication between cardiomyocytes and fibroblasts in the heart. Myocyte-fibroblast interactions occur via both direct and indirect means including paracrine mediators, extracellular matrix interactions, electrical modulators, mechanical junctions, and membrane nanotubes. In the diseased heart, cardiomyocyte and fibroblast ratios and activity, and thus myocyte-fibroblast interactions, change and are thought to contribute to the course of disease including development of fibrosis and arrhythmogenic activity. Fibroblasts have a developing role in modulating cardiomyocyte electrical and hypertrophic activity, however gaps in knowledge regarding these interactions still exist. Research in this field has necessitated the development of unique approaches to isolate and control myocyte-fibroblast interactions. Numerous methods for 2D and 3D co-culture systems have been developed, while a growing part of this field is in the use of better tools for in vivo systems including cardiomyocyte and fibroblast specific Cre mouse lines for cell type specific genetic ablation. This review will focus on (i) mechanisms of myocyte-fibroblast communication and their effects on disease features such as cardiac fibrosis and arrhythmias as well as (ii) methods being used and currently developed in this field. PMID:26996756

  1. Subsampling technique to enhance the decoded output of JTC encrypting system

    Science.gov (United States)

    Barrera, John Fredy; Rueda, Edgar; Ríos, Carlos; Tebaldi, Myrian; Bolognini, Nestor; Torroba, Roberto

    2011-08-01

    Optical systems have physical restrictions that impose limits in the finest spatial feature that can be processed. In this work we combine a subsampling procedure with a multiplexing technique to overtake the limit on the information that is processed in a JTC encryption system. In the process the object is divided in subsamples and each subsample is encrypted separately. Then the encrypted subsamples are multiplexed. The encryption of the subsamples is performed in a real optical JTC encrypting system. The multiplexing and the decryption process are carried out by means of a virtual optical system. Experimental results are presented to show the validity of the proposal.

  2. A preliminary study into performing routine tube output and automatic exposure control quality assurance using radiology information system data

    International Nuclear Information System (INIS)

    Data are currently being collected from hospital radiology information systems in the North West of the UK for the purposes of both clinical audit and patient dose audit. Could these data also be used to satisfy quality assurance (QA) requirements according to UK guidance? From 2008 to 2009, 731 653 records were submitted from 8 hospitals from the North West England. For automatic exposure control QA, the protocol from Inst. of Physics and Engineering in Medicine (IPEM) report 91 recommends that milli amperes per second can be monitored for repeatability and reproducibility using a suitable phantom, at 70-81 kV. Abdomen AP and chest PA examinations were analysed to find the most common kilo voltage used with these records then used to plot average monthly milli amperes per second with time. IPEM report 91 also recommends that a range of commonly used clinical settings is used to check output reproducibility and repeatability. For each tube, the dose area product values were plotted over time for two most common exposure factor sets. Results show that it is possible to do performance checks of AEC systems; however more work is required to be able to monitor tube output performance. Procedurally, the management system requires work and the benefits to the workflow would need to be demonstrated. (authors)

  3. Real-Time Wavelet-Based Coordinated Control of Hybrid Energy Storage Systems for Denoising and Flattening Wind Power Output

    Directory of Open Access Journals (Sweden)

    Tran Thai Trung

    2014-10-01

    Full Text Available Since the penetration level of wind energy is continuously increasing, the negative impact caused by the fluctuation of wind power output needs to be carefully managed. This paper proposes a novel real-time coordinated control algorithm based on a wavelet transform to mitigate both short-term and long-term fluctuations by using a hybrid energy storage system (HESS. The short-term fluctuation is eliminated by using an electric double-layer capacitor (EDLC, while the wind-HESS system output is kept constant during each 10-min period by a Ni-MH battery (NB. State-of-charge (SOC control strategies for both EDLC and NB are proposed to maintain the SOC level of storage within safe operating limits. A ramp rate limitation (RRL requirement is also considered in the proposed algorithm. The effectiveness of the proposed algorithm has been tested by using real time simulation. The simulation model of the wind-HESS system is developed in the real-time digital simulator (RTDS/RSCAD environment. The proposed algorithm is also implemented as a user defined model of the RSCAD. The simulation results demonstrate that the HESS with the proposed control algorithm can indeed assist in dealing with the variation of wind power generation. Moreover, the proposed method shows better performance in smoothing out the fluctuation and managing the SOC of battery and EDLC than the simple moving average (SMA based method.

  4. Regulation of Cardiac Hypertrophy: the nuclear option

    NARCIS (Netherlands)

    D.W.D. Kuster (Diederik)

    2011-01-01

    textabstractCardiac hypertrophy is the response of the heart to an increased workload. After myocardial infarction (MI) the surviving muscle tissue has to work harder to maintain cardiac output. This sustained increase in workload leads to cardiac hypertrophy. Despite its apparent appropriateness, c

  5. A Communication Protocol and Monitoring Policy for Input/Output Vehicles in an Automatic Storage and Retrieval System

    Institute of Scientific and Technical Information of China (English)

    LI Li; LI Wenfeng; LIAO Xiaoping; SU Wengui; LIN Yizhong

    2006-01-01

    The acquisition and processing of equipment information is pivotal to control and management of the automated storage and retrieval system. The work of this paper is based on the automatic storage and retrieval experimental system of Wuhan University of Technology. First, the output/input flow and the control information of storage/retrieval vehicle are studied and the plotting finite state machine model of the stacking crane is established. Then, the communication protocol between the center control management computer and the PLC of stacking crane is designed. Finally, the stacking crane's monitoring data, which include operating time, running states and real-time position status, are gained by analyzing the communication protocol. The detailed program for the acquisition and processing of monitoring information is developed. This method is suitable for the equipment monitoring of the whole system, and provides a platform for studying the intelligent control and optimal scheduling strategies of AS/RS.

  6. Partnership in a Dynamic Production System with Unobservable Actions and Noncontractible Output

    OpenAIRE

    Plambeck, EL; Taylor, TA

    2006-01-01

    This paper considers two firms that engage in joint production. The prospect of repeated interaction introduces dynamics, in that actions that firms take today influence the costliness and effectiveness of actions in the future. Repeated interaction also facilitates the use of informal agreements (relational contracts) that are sustained not by the court system, but by the ongoing value of the relationship. We characterize the optimal relational contract in this dynamic system with double mor...

  7. Develop the dual fuel conversion system for high output, medium speed diesel engines. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-16

    The original plan for the project involved design modifications to an existing system to enhance its performance and increase the limit of power that was achieved by the original design and to apply the higher performance product to the full sized engine and test its performance. The new system would also be applied to a different engine model. The specific work would include the redesign of gas injectors, piston configurations and two types of igniters, engine instrumentation, monitoring and testing.

  8. A new nonlinear output tracking controller via output-feedback

    Institute of Scientific and Technical Information of China (English)

    Yun ZHANG; Yungang LIU; Yuqin DING

    2006-01-01

    In this paper, the output tracking control is investigated for a class of nonlinear systems when only output is available for feedback. Based on the multivariable analog of circle criterion, an observer is first introduced. Then, the observer-based output tracking controller is constructively designed by using the integral backstepping approach together with completing square. It is shown that, under relatively mild conditions, all the closed-loop signals are uniformly bounded.Meanwhile the system output asymptotically tracks the desired output. A simulation example is given to illustrate the effectiveness of the theoretical results.

  9. The Capacity Gain of Orbital Angular Momentum Based Multiple-Input-Multiple-Output System

    Science.gov (United States)

    Zhang, Zhuofan; Zheng, Shilie; Chen, Yiling; Jin, Xiaofeng; Chi, Hao; Zhang, Xianmin

    2016-05-01

    Wireless communication using electromagnetic wave carrying orbital angular momentum (OAM) has attracted increasing interest in recent years, and its potential to increase channel capacity has been explored widely. In this paper, we compare the technique of using uniform linear array consist of circular traveling-wave OAM antennas for multiplexing with the conventional multiple-in-multiple-out (MIMO) communication method, and numerical results show that the OAM based MIMO system can increase channel capacity while communication distance is long enough. An equivalent model is proposed to illustrate that the OAM multiplexing system is equivalent to a conventional MIMO system with a larger element spacing, which means OAM waves could decrease the spatial correlation of MIMO channel. In addition, the effects of some system parameters, such as OAM state interval and element spacing, on the capacity advantage of OAM based MIMO are also investigated. Our results reveal that OAM waves are complementary with MIMO method. OAM waves multiplexing is suitable for long-distance line-of-sight (LoS) communications or communications in open area where the multi-path effect is weak and can be used in massive MIMO systems as well.

  10. The Capacity Gain of Orbital Angular Momentum Based Multiple-Input-Multiple-Output System.

    Science.gov (United States)

    Zhang, Zhuofan; Zheng, Shilie; Chen, Yiling; Jin, Xiaofeng; Chi, Hao; Zhang, Xianmin

    2016-01-01

    Wireless communication using electromagnetic wave carrying orbital angular momentum (OAM) has attracted increasing interest in recent years, and its potential to increase channel capacity has been explored widely. In this paper, we compare the technique of using uniform linear array consist of circular traveling-wave OAM antennas for multiplexing with the conventional multiple-in-multiple-out (MIMO) communication method, and numerical results show that the OAM based MIMO system can increase channel capacity while communication distance is long enough. An equivalent model is proposed to illustrate that the OAM multiplexing system is equivalent to a conventional MIMO system with a larger element spacing, which means OAM waves could decrease the spatial correlation of MIMO channel. In addition, the effects of some system parameters, such as OAM state interval and element spacing, on the capacity advantage of OAM based MIMO are also investigated. Our results reveal that OAM waves are complementary with MIMO method. OAM waves multiplexing is suitable for long-distance line-of-sight (LoS) communications or communications in open area where the multi-path effect is weak and can be used in massive MIMO systems as well. PMID:27146453

  11. Local heterogeneities in cardiac systems suppress turbulence by generating multi-armed rotors

    Science.gov (United States)

    Zhang, Zhihui; Steinbock, Oliver

    2016-05-01

    Ventricular fibrillation is an extremely dangerous cardiac arrhythmia that is linked to rotating waves of electric activity and chaotically moving vortex lines. These filaments can pin to insulating, cylindrical heterogeneities which swiftly become the new rotation backbone of the local wave field. For thin cylinders, the stabilized rotation is sufficiently fast to repel the free segments of the turbulent filament tangle and annihilate them at the system boundaries. The resulting global wave pattern is periodic and highly ordered. Our cardiac simulations show that also thicker cylinders can establish analogous forms of tachycardia. This process occurs through the spontaneous formation of pinned multi-armed vortices. The observed number of wave arms N depends on the cylinder radius and is associated to stability windows that for N = 2, 3 partially overlap. For N = 1, 2, we find a small gap in which the turbulence is removed but the pinned rotor shows complex temporal dynamics. The relevance of our findings to human cardiology are discussed in the context of vortex pinning to more complex-shaped anatomical features and remodeled myocardium.

  12. Multichannel SQUID system detecting tangential components of the cardiac magnetic field

    Science.gov (United States)

    Tsukada, Keiji; Haruta, Yasuhiro; Adachi, Akira; Ogata, Hisanao; Komuro, Takanori; Ito, Tsuyoshi; Takada, Youichi; Kandori, Akihiko; Noda, Yasunaga; Terada, Yasushi; Mitsui, Toshio

    1995-10-01

    The 32-channel SQUID system described here is used for diagnosing heart disease by measuring the x and y components of the cardiac magnetic field. To detect a magnetic field parallel to the body surface, it uses a compact hybrid superconducting quantum interference device (SQUID) gradiometer consisting of a planar pickup coil (fabricated using thin-film techniques) and a square double-washer dc-SQUID having large voltage-flux transfer function. The SQUIDs are operated in a flux-locked mode using simple readout circuits connected directly to the preamplifier without additional positive feedback. The system is installed in a magnetically shielded room in a hospital. A low noise characteristics lower than 10 ft/√ Hz in a white noise is obtained in the hospital. Examples of tangential magnetocardiogram (MCG) measurements presented here show that the MCG obtained using this gradiometer makes it easy to visually estimate the electrophysiological behavior of the heart.

  13. Scattered radiation doses during cardiac studies using a U-arm type fluoroscopy system

    International Nuclear Information System (INIS)

    The advent of image intensifier systems incorporating a U-arm with parallelogram support, a greater awareness of scattered radiation levels is needed, in particular to cardiologists. Depending on the projection, the cardiologist can now be subjected to scatter from the primary side of the patient, giving rise to much higher levels of scattered radiation. Doses to cardiologists were measured for typical cardiac studies on such an image intensifier system. Doses to the eyes and thyroid were below the limits recommended by the ICRP, but if the principle of ALARA is to be adhered to consideration needs to be given to a secondary barrier, in addition to the lead apron, to provide protection to the eyes and thyroid of the cardiologist

  14. A Real-Time Health Monitoring System for Remote Cardiac Patients Using Smartphone and Wearable Sensors.

    Science.gov (United States)

    Kakria, Priyanka; Tripathi, N K; Kitipawang, Peerapong

    2015-01-01

    Online telemedicine systems are useful due to the possibility of timely and efficient healthcare services. These systems are based on advanced wireless and wearable sensor technologies. The rapid growth in technology has remarkably enhanced the scope of remote health monitoring systems. In this paper, a real-time heart monitoring system is developed considering the cost, ease of application, accuracy, and data security. The system is conceptualized to provide an interface between the doctor and the patients for two-way communication. The main purpose of this study is to facilitate the remote cardiac patients in getting latest healthcare services which might not be possible otherwise due to low doctor-to-patient ratio. The developed monitoring system is then evaluated for 40 individuals (aged between 18 and 66 years) using wearable sensors while holding an Android device (i.e., smartphone under supervision of the experts). The performance analysis shows that the proposed system is reliable and helpful due to high speed. The analyses showed that the proposed system is convenient and reliable and ensures data security at low cost. In addition, the developed system is equipped to generate warning messages to the doctor and patient under critical circumstances. PMID:26788055

  15. A Real-Time Health Monitoring System for Remote Cardiac Patients Using Smartphone and Wearable Sensors

    Directory of Open Access Journals (Sweden)

    Priyanka Kakria

    2015-01-01

    Full Text Available Online telemedicine systems are useful due to the possibility of timely and efficient healthcare services. These systems are based on advanced wireless and wearable sensor technologies. The rapid growth in technology has remarkably enhanced the scope of remote health monitoring systems. In this paper, a real-time heart monitoring system is developed considering the cost, ease of application, accuracy, and data security. The system is conceptualized to provide an interface between the doctor and the patients for two-way communication. The main purpose of this study is to facilitate the remote cardiac patients in getting latest healthcare services which might not be possible otherwise due to low doctor-to-patient ratio. The developed monitoring system is then evaluated for 40 individuals (aged between 18 and 66 years using wearable sensors while holding an Android device (i.e., smartphone under supervision of the experts. The performance analysis shows that the proposed system is reliable and helpful due to high speed. The analyses showed that the proposed system is convenient and reliable and ensures data security at low cost. In addition, the developed system is equipped to generate warning messages to the doctor and patient under critical circumstances.

  16. One Output Function: A Misconception of Students Studying Digital Systems--A Case Study

    Science.gov (United States)

    Trotskovsky, E.; Sabag, N.

    2015-01-01

    Background: Learning processes are usually characterized by students' misunderstandings and misconceptions. Engineering educators intend to help their students overcome their misconceptions and achieve correct understanding of the concept. This paper describes a misconception in digital systems held by many students who believe that combinational…

  17. Control of Linear Systems with Preisach Hysteresis Output with Application to Damage Reduction

    DEFF Research Database (Denmark)

    Barradas Berglind, Jose de Jesus; Wisniewski, Rafal

    The focus of this work is on the Preisach hysteresis operator which has been widely used in fields such as ferromagnetics, phase transitions, filtration through porous media, and shape memory alloys. The main purpose is to incorporate discrete linear time invariant systems with discretized Preisach...

  18. Test for Nonlinear Input Output Relations in SISO Systems by Preliminary Data Analysis

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2000-01-01

    This paper discusses and develops preliminary statistical tests for detecting nonlinearities in the deterministic part of SISO systems with noise. The most referenced method is unreliable for common noise processes as e.g.\\ colored. Therefore two new methods based on superposition and sinus input...

  19. Theory and investigation of acoustic multiple-input multiple-output systems based on spherical arrays in a room.

    Science.gov (United States)

    Morgenstern, Hai; Rafaely, Boaz; Zotter, Franz

    2015-11-01

    Spatial attributes of room acoustics have been widely studied using microphone and loudspeaker arrays. However, systems that combine both arrays, referred to as multiple-input multiple-output (MIMO) systems, have only been studied to a limited degree in this context. These systems can potentially provide a powerful tool for room acoustics analysis due to the ability to simultaneously control both arrays. This paper offers a theoretical framework for the spatial analysis of enclosed sound fields using a MIMO system comprising spherical loudspeaker and microphone arrays. A system transfer function is formulated in matrix form for free-field conditions, and its properties are studied using tools from linear algebra. The system is shown to have unit-rank, regardless of the array types, and its singular vectors are related to the directions of arrival and radiation at the microphone and loudspeaker arrays, respectively. The formulation is then generalized to apply to rooms, using an image source method. In this case, the rank of the system is related to the number of significant reflections. The paper ends with simulation studies, which support the developed theory, and with an extensive reflection analysis of a room impulse response, using the platform of a MIMO system. PMID:26627773

  20. Cross-Correlation of Photovoltaic Output Fluctuation in Power System Operation for Large-Scale Photovoltaic Integration

    OpenAIRE

    Ikeda, Yuichi; Ogimoto, Kazuhiko

    2013-01-01

    We analyzed the cross-correlation of Photovoltaic (PV) output fluctuation for the actual PV output time series data in both the Tokyo area and the whole of Japan using the principal component analysis with the random matrix theory. Based on the obtained cross-correlation coefficients, the forecast error for PV output was estimated with/without considering the cross-correlations. Then operation schedule of thermal plants is calculated to integrate PV output using our unit commitment model with...