Please find a selection of my research papers. Feel free to contact me if you cannot find a particular manuscript here on Mendeley, ResearchGate, or Google Scholar.


  2016 (1)
Evaluation of cardiac modulation in children in response to apnea/hypopnea using the Phone Oximeter â?¢. Dehkordi, P.; Garde, A.; Karlen, W.; Petersen, C., L.; Wensley, D.; Dumont, G., A.; and Mark Ansermino, J. Physiological Measurement, 37(2): 187-202. 2 2016.
Evaluation of cardiac modulation in children in response to apnea/hypopnea using the Phone Oximeter â?¢ [link]Website   bibtex
  2015 (8)
Variability in estimating shunt from single pulse oximetry measurements. Karlen, W.; Petersen, C., L.; Dumont, G., A.; and Ansermino, J., M. Physiological Measurement, 36(5): 967-981. 5 2015.
Variability in estimating shunt from single pulse oximetry measurements [link]Website   bibtex
A cohort study of morbidity, mortality and health seeking behavior following rural health center visits by children under 12 in Southwestern Uganda. Wiens, M., O.; Gan, H.; Barigye, C.; Zhou, G.; Kumbakumba, E.; Kabakyenga, J.; Kissoon, N.; Ansermino, J., M.; Karlen, W.; Larson, C., P.; and MacLeod, S., M. PLoS ONE, 10(1): e0118055. 2015.
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Estimation of Respiratory Rate From Photoplethysmographic Imaging Videos Compared to Pulse Oximetry. Karlen, W.; Garde, A.; Myers, D.; Scheffer, C.; Ansermino, J., M.; and Dumont, G., A. IEEE Journal of Biomedical and Health Informatics, 19(4): 1331-1338. 7 2015.
Estimation of Respiratory Rate From Photoplethysmographic Imaging Videos Compared to Pulse Oximetry [link]Website   bibtex
Efficiency of respiratory rate measurements: Comment on Black et al., 2015: â??Can simple mobile phone applications provide reliable counts of respiratory rates in sick infants and children? An initial evaluation of three new applicationsâ??. Karlen, W.; Dunsmuir, D.; and Ansermino, J., M. International Journal of Nursing Studies, 52(7): 1279-1280. 7 2015.
Efficiency of respiratory rate measurements: Comment on Black et al., 2015: â??Can simple mobile phone applications provide reliable counts of respiratory rates in sick infants and children? An initial evaluation of three new applicationsâ?? [link]Website   bibtex
Medical Devices and Information Communication Technologies for the Base of the Pyramid. Friedman, Z.; and Karlen, W. 11, pages 113-118. Springer International Publishing, 2015.
Medical Devices and Information Communication Technologies for the Base of the Pyramid [link]Website   bibtex
Data Quality in mHealth. Karlen, W. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2015.
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Development and Internal Validation of a Predictive Model Including Pulse Oximetry for Hospitalization of Under-Five Children in Bangladesh. Raihana, S.; Dunsmuir, D.; Huda, T.; Zhou, G.; Rahman, Q., S.; Garde, A.; Moinuddin, M.; Karlen, W.; Dumont, G., A.; Kissoon, N.; El Arifeen, S.; Larson, C.; and Ansermino, J., M. PLoS ONE, 10(11): e0143213. 11 2015.
Development and Internal Validation of a Predictive Model Including Pulse Oximetry for Hospitalization of Under-Five Children in Bangladesh [link]Website   bibtex
The Performance of a Mobile Phone Respiratory Rate Counter Compared to the WHO ARI Timer. Gan, H.; Karlen, W.; Dunsmuir, D.; Zhou, G.; Chiu, M.; Dumont, G., A.; and Ansermino, J., M. Journal of Healthcare Engineering, 6(4): 691-704. 12 2015.
The Performance of a Mobile Phone Respiratory Rate Counter Compared to the WHO ARI Timer [link]Website   bibtex
  2014 (12)
Improving the accuracy and efficiency of respiratory rate measurements in children using mobile devices. Karlen, W.; Gan, H.; Chiu, M.; Dunsmuir, D.; Zhou, G.; Dumont, G., A.; and Ansermino, J., M. PLoS ONE, 9(6): e99266. 2014.
Improving the accuracy and efficiency of respiratory rate measurements in children using mobile devices. [link]Website   bibtex   abstract   5 downloads
Sharing Vital Signs between Mobile Phone Applications. Karlen, W.; Dumont, G., A.; and Scheffer, C. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 3646-9, 2014.
bibtex   1 download
Mobile Point-of-Care Monitors and Diagnostic Device Design. of Devices, Circuits, and SystemsCRC Press, 2014.
Mobile Point-of-Care Monitors and Diagnostic Device Design [link]Website   bibtex   buy
Sleep Stage Classification in Children Using Photoplethysmogram Pulse Rate Variability. Dehkordi, P.; Garde, A.; Karlen, W.; Wensley, D.; Ansermino, J., M.; and Dumont, G., A. In Computing in Cardiology Conference (CinC), pages 297-300, 2014.
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Design of an interactive medical guideline application for community health workers. Karlen, W.; and Scheffer, C. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 1366-1369, 2014.
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Respiratory Rate Assessment from Photoplethysmographic Imaging. Karlen, W.; Garde, A.; Myers, D.; Scheffer, C.; Ansermino, J., M.; and Dumont, G., A. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, pages 5397-400, 2014. IEEE Engineering in Medicine and Biology Society
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Oxygen Saturation Resolution Influences Regularity Measurements. Garde, A.; Karlen, W.; Dehkordi, P.; Ansermino, J., M.; and Dumont, G., A. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, pages 2257-60, 2014. IEEE Engineering in Medicine and Biology Society
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Development of a screening tool for sleep disordered breathing in children using the phone oximeterâ?¢. Garde, A.; Dehkordi, P.; Karlen, W.; Wensley, D.; Ansermino, J., M.; and Dumont, G., A. PLoS ONE, 9(11): e112959. 1 2014.
Development of a screening tool for sleep disordered breathing in children using the phone oximeterâ?¢. [link]Website   bibtex   abstract
Detrended fluctuation analysis of photoplethysmogram pulse rate intervals in sleep disordered breathing. Dehkordi, P.; Garde, A.; Karlen, W.; Petersen, C., L.; Ansermino, M., J.; and Dumont, A., G. In 2014 IEEE Healthcare Innovation Conference (HIC), pages 323-326, 2014. IEEE Engineering in Medicine and Biology Society
Detrended fluctuation analysis of photoplethysmogram pulse rate intervals in sleep disordered breathing [link]Website   bibtex
Assessing the Quality of Manual Respiratory Rate Measurements using Mobile Devices. Karlen, W.; Wiens, M., O.; Gan, H.; Dunsmuir, D.; Chiu, M.; Dumont, G., A.; and Ansermino, J., M. In Appropriate Healthcare Technologies for Low Resource Settings (AHT 2014), pages 1-4, 2014. IET
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Estimating respiratory and heart rates from the correntropy spectral density of the photoplethysmogram. Garde, A.; Karlen, W.; Ansermino, J., M.; and Dumont, G., A. PLoS ONE, 9(1): e86427. 1 2014.
Estimating respiratory and heart rates from the correntropy spectral density of the photoplethysmogram. [link]Website   bibtex   abstract   32 downloads
Where do pulse oximeter probes break?. Crede, S.; Van der Merwe, G.; Hutchinson, J.; Woods, D.; Karlen, W.; and Lawn, J. Journal of clinical monitoring and computing, 28(3): 309-14. 2014.
Where do pulse oximeter probes break? [link]Website   bibtex   abstract
  2013 (8)
Monitoring nociception during general anesthesia with cardiorespiratory coherence. Brouse, C., J.; Karlen, W.; Dumont, G., A.; Myers, D.; Cooke, E.; Stinson, J.; Lim, J.; and Ansermino, J., M. Journal of clinical monitoring and computing, 27(5): 551-60. 10 2013.
Monitoring nociception during general anesthesia with cardiorespiratory coherence. [link]Website   bibtex   abstract
Recognition of correct finger placement for photoplethysmographic imaging. Karlen, W.; Lim, J.; Ansermino, J., M.; Dumont, G., A.; and Scheffer, C. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 7480-3, 7 2013.
Recognition of correct finger placement for photoplethysmographic imaging [link]Website   bibtex   abstract   1 download
Detection of the optimal region of interest for camera oximetry. Karlen, W.; Ansermino, J., M.; Dumont, G., A.; and Scheffer, C. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 2263-6, 7 2013.
Detection of the optimal region of interest for camera oximetry [link]Website   bibtex   abstract   2 downloads
Pulse rate variability compared with heart rate variability in children with and without sleep disordered breathing. Dehkordi, P.; Garde, A.; Karlen, W.; Wensley, D.; Ansermino, J., M.; and Dumont, G., A. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, pages 6563-6, 2013.
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Analysis of Oxygen Saturation in Children with Obstructive Sleep Apnea Using the Phone-Oximeter. Garde, A.; Karlen, W.; Dehkordi, P.; Wensley, D.; Ansermino, J., M.; and Dumont, G., A. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, volume 4, pages 2531-4, 2013.
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Pulse Rate Variability in Children with Disordered Breathing During Different Sleep Stages. Dehkordi, P.; Garde, A.; Karlen, W.; Wensley, D.; Ansermino, J., M.; and Dumont, G., A. In Computing in Cardiology Conference (CinC), volume 40, pages 1015 - 8, 9 2013. IEEE
Pulse Rate Variability in Children with Disordered Breathing During Different Sleep Stages [link]Website   bibtex
Multiparameter respiratory rate estimation from the photoplethysmogram. Karlen, W.; Raman, S.; Ansermino, J., M.; and Dumont, G., A. IEEE transactions on bio-medical engineering, 60(7): 1946-53. 7 2013.
Multiparameter respiratory rate estimation from the photoplethysmogram. [link]Website   bibtex   abstract   10 downloads
Empirical mode decomposition for respiratory and heart rate estimation from the photoplethysmogram. Garde, A.; Karlen, W.; Dehkordi, P.; Ansermino, J., M.; and Dumont, G., A. In Computing in Cardiology (CinC), volume 40, pages 799-802, 9 2013. IEEE
Empirical mode decomposition for respiratory and heart rate estimation from the photoplethysmogram [link]Website   bibtex   15 downloads
  2012 (10)
The Phone Oximeter for Mobile Spot-Check. Dunsmuir, D.; Petersen, C.; Karlen, W.; Lim, J.; Dumont, G., A.; and Ansermino, J., M. In Abstracts of the 2012 Annual Meeting of the Society for Technology in Anesthesia (STA), volume 115, pages S21, 2012. Anesthesia and analgesia
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Photoplethysmogram Processing Using An Adaptive Single Frequency Phase Vocoder Algorithm. Karlen, W.; Petersen, C.; Gow, J.; Ansermino, J., M.; and Dumont, G., A. pages 31-42. Springer-Verlag, 2012.
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Usability testing of a prototype Phone Oximeter with healthcare providers in high- and low-medical resource environments. Hudson, J.; Nguku, S., M.; Sleiman, J.; Karlen, W.; Dumont, G., A.; Petersen, C.; Warriner, C., B.; and Ansermino, J., M. Anaesthesia, 67(9): 957-67. 2012.
Usability testing of a prototype Phone Oximeter with healthcare providers in high- and low-medical resource environments [link]Website   bibtex   abstract
Design challenges for camera oximetry on a mobile phone. Karlen, W.; Lim, J.; Ansermino, J., M.; Dumont, G.; and Scheffer, C. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 2448-51, 1 2012.
Design challenges for camera oximetry on a mobile phone [link]Website   bibtex   abstract
Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation. Karlen, W.; Kobayashi, K.; Ansermino, J., M.; and Dumont, G., A. Physiological measurement, 33(10): 1617-29. 9 2012.
Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation. [link]Website   bibtex   abstract   16 downloads
Real-time cardiorespiratory coherence detects antinociception during general anesthesia. Brouse, C., J.; Karlen, W.; Dumont, G., A.; Myers, D.; Cooke, E.; Stinson, J.; Lim, J.; and Ansermino, J., M. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, volume 2012, pages 3813-6, 1 2012.
Real-time cardiorespiratory coherence detects antinociception during general anesthesia. [link]Website   bibtex   abstract
Measuring Adequacy of Analgesia with Cardiorespiratory Coherence. Brouse, C., J.; Karlen, W.; Dumont, G., A.; Myers, D.; Cooke, E.; Stinson, J.; Lim, J.; and Ansermino, J., M. In Abstracts of the 2012 Annual Meeting of the Society for Technology in Anesthesia (STA), volume 115, pages S8, 2012. Anesthesia and analgesia
Measuring Adequacy of Analgesia with Cardiorespiratory Coherence [link]Website   bibtex
A Data Fusion Approach for RR estimation from PPG (STA Engineering Challenge). Raman, S.; Brouse, C., J.; Karlen, W.; Dumont, G., A.; and Ansermino, J., M. In Proceedings of the 2012 Society for Technology in Anesthesia Annual Meeting, volume 31, 2012.
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Adaptive Pulse Segmentation and Artifact Detection in Photoplethysmography for Mobile Applications. Karlen, W.; Ansermino, J., M.; and Dumont, G., A. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society, pages 3131-4, 8 2012.
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Pulse oximeter plethysmograph variation and its relationship to the arterial waveform in mechanically ventilated children. Chandler, J., R.; Cooke, E.; Petersen, C.; Karlen, W.; Froese, N.; Lim, J.; and Ansermino, J., M. Journal of clinical monitoring and computing, 26(3): 145-51. 6 2012.
Pulse oximeter plethysmograph variation and its relationship to the arterial waveform in mechanically ventilated children. [link]Website   bibtex   abstract
  2011 (8)
An Adaptive Single Frequency Phase Vocoder For Low-power Heart Rate Detection. Karlen, W.; Petersen, C.; Gow, J.; Ansermino, J., M.; and Dumont, G., A. In BIODEVICES 2011 - Proceedings of the International Conference on Biomedical Electronics and Devices, Rome, Italy, January 26-29, 2011, pages 30-35, 2011. INSTICC Press
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SleepPic. Hardware Developments for a Wearable On-line Sleep and Wake Discrimination System. Karlen, W.; and Floreano, D. In Proceedings of BIOSIGNALS 2011 - International Conference on Bio-inspired Systems and Signal Processing, Rome, Italy, January 26-29, 2011, pages 132-7, 2011. SciTePress
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Human-centered Phone Oximeter Interface Design for the Operating Room. Karlen, W.; Dumont, G., A.; Petersen, C.; Gow, J.; Lim, J.; Sleiman, J.; and Ansermino, J., M. In Proceedings of the International Conference on Health Informatics, pages 433-8, 2011. SciTePress - Science and and Technology Publications
Human-centered Phone Oximeter Interface Design for the Operating Room [link]Website   bibtex   abstract
Location independence in patient monitoring. Karlen, W.; Blackstock, M.; and Ansermino, J., M. In Abstracts of the 2011 Annual Meeting of the Society for Technology in Anesthesia (STA). January 12-15, 2011. Las Vegas, Nevada, USA., volume 113, pages S37, 8 2011. Anesthesia and Analgesia
Location independence in patient monitoring [link]Website   bibtex   abstract
Automated Validation of Capillary Refill Time Measurements Using Photo-Plethysmogram from a Portable Device for Effective Triage in Children. Karlen, W.; Pickard, A.; Daniels, J.; Kwizera, A.; Ibingira, C.; Dumont, G., A.; and Ansermino, J., M. In 2011 IEEE Global Humanitarian Technology Conference, pages 66-71, 10 2011. IEEE
Automated Validation of Capillary Refill Time Measurements Using Photo-Plethysmogram from a Portable Device for Effective Triage in Children [link]Website   bibtex   abstract
Respiratory rate estimation using respiratory sinus arrhythmia from photoplethysmography. Karlen, W.; Brouse, C., J.; Cooke, E.; Ansermino, J., M.; and Dumont, G., A. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 1201-4, 8 2011.
Respiratory rate estimation using respiratory sinus arrhythmia from photoplethysmography. [link]Website   bibtex   abstract   3 downloads
Wavelet transform cardiorespiratory coherence detects patient movement during general anesthesia. Brouse, C., J.; Karlen, W.; Myers, D.; Cooke, E.; Stinson, J.; Lim, J.; Dumont, G., A.; and Ansermino, J., M. In Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference, volume 2011, pages 6114-7, 8 2011.
Wavelet transform cardiorespiratory coherence detects patient movement during general anesthesia. [link]Website   bibtex   abstract
Medical intelligence article: capillary refill time: is it still a useful clinical sign?. Pickard, A.; Karlen, W.; and Ansermino, J., M. Anesthesia and analgesia, 113(1): 120-3. 7 2011.
Medical intelligence article: capillary refill time: is it still a useful clinical sign? [link]Website   bibtex   abstract
  2010 (4)
Capillary Refill Time Assessment Using a Mobile Phone Application (iRefill). Karlen, W.; Petersen, C.; Pickard, A.; Dumont, G., A.; and Ansermino, J., M. In Proceedings of the 2010 Annual Meeting of the American Society Anesthesiologists, pages A575, 2010. American Society of Anesthesiologists
Capillary Refill Time Assessment Using a Mobile Phone Application (iRefill) [link]Website   bibtex   abstract
Enhancing pilot performance with a SymBodic system. Karlen, W.; Cardin, S.; Thalmann, D.; and Floreano, D. In Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference, volume 1, pages 6599-602, 1 2010. IEEE Engineering in Medicine and Biology Society
Enhancing pilot performance with a SymBodic system. [link]Website   bibtex   abstract
Adaptive Sleep-Wake Discrimination for Wearable Devices. Karlen, W.; and Floreano, D. IEEE transactions on bio-medical engineering, 58(4): 920-6. 12 2010.
Adaptive Sleep-Wake Discrimination for Wearable Devices [link]Website   bibtex   abstract   3 downloads
CapnoBase: Signal database and tools to collect, share and annotate respiratory signals. Karlen, W.; Turner, M.; Cooke, E.; Dumont, G., A.; and Ansermino, J., M. In Annual Meeting of the Society for Technology in Anesthesia (STA), pages 25, 2010.
CapnoBase: Signal database and tools to collect, share and annotate respiratory signals [link]Website   bibtex   abstract
  2009 (3)
Evolutionary Selection of Features for Neural Sleep/Wake Discrimination. Duerr, P.; Karlen, W.; Guignard, J.; and Mattiussi, C. Journal of Artificial Evolution and Applications, 2009: 1-10. 2009.
Evolutionary Selection of Features for Neural Sleep/Wake Discrimination [link]Website   bibtex   abstract
Adaptive Wake and Sleep Detection for Wearable Systems. Karlen, W. Ph.D. Thesis, 2009.
Adaptive Wake and Sleep Detection for Wearable Systems [link]Website   bibtex   abstract
Sleep and Wake Classification With ECG and Respiratory Effort Signals. Karlen, W.; Mattiussi, C.; and Floreano, D. IEEE Transactions on Biomedical Circuits and Systems, 3(2): 71-8. 2009.
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  2008 (1)
Improving actigraph sleep/wake classification with cardio-respiratory signals. Karlen, W.; Mattiussi, C.; and Floreano, D. In Annual International Conference of the IEEE Engineering in Medicine and Biology Society., pages 5262-5, 1 2008. IEEE Engineering in Medicine and Biology Society
Improving actigraph sleep/wake classification with cardio-respiratory signals. [link]Website   bibtex   abstract
  2007 (1)
Adaptive Sleep/Wake Classification Based on Cardiorespiratory Signals for Wearable Devices. Karlen, W.; Mattiussi, C.; and Floreano, D. In 2007 IEEE Biomedical Circuits and Systems Conference, pages 203-6, 11 2007. IEEE
Adaptive Sleep/Wake Classification Based on Cardiorespiratory Signals for Wearable Devices [link]Website   bibtex   abstract   1 download
  2006 (1)
Robot-animal interaction: Perception and behavior of insbot. Asadpour, M.; Tâche, F.; Caprari, G.; Karlen, W.; and Siegwart, R. International Journal of Advanced Robotic Systems, 3(2): 093-098. 2006.
Robot-animal interaction: Perception and behavior of insbot [link]Website   bibtex   abstract
  2005 (1)
Perception and behavior of InsBot : Robot-Animal interaction issues. Tâche, F.; Asadpour, M.; Caprari, G.; Karlen, W.; and Siegwart, R. In 2005 IEEE International Conference on Robotics and Biomimetics - ROBIO, pages 517-522, 2005. IEEE
Perception and behavior of InsBot : Robot-Animal interaction issues [link]Website   bibtex   abstract

© Walter Karlen, 2008-2012
last update:04.11.2014