Smart technologies toward sleep monitoring at home

With progress in sensors and communication technologies, the range of sleep monitoring is extending from professional clinics into our usual home environments. Information from conventional overnight polysomnographic recordings can be derived from much simpler devices and methods. The gold standard of sleep monitoring is laboratory polysomnography, which classifi es brain states based mainly on EEGs. Single-channel EEGs have been used for sleep stage scoring with accuracies of 84.9%. Actigraphy can estimate sleep effi ciency with an accuracy of 86.0%. Sleep scoring based on respiratory dynamics provides accuracies of 89.2% and 70.9% for identifying sleep stages and sleep effi ciency, respectively, and a correlation coeffi cient of 0.94 for apnea–hypopnea detection. Modulation of autonomic balance during the sleep stages are well recognized and widely used for simpler sleep scoring and sleep parameter estimation. This modulation can be recorded by several types of cardiovascular measurements, including ECG, PPG, BCG, and PAT, and the results showed accuracies up to 96.5% and 92.5% for sleep effi ciency and OSA severity detection, respectively. Instead of using recordings for the entire night, less than 5 min ECG recordings have used for sleep effi ciency and AHI estimation and resulted in high correlations of 0.94 and 0.99, respectively. These methods are based on their own models that relate sleep dynamics with a limited number of biological signals. Parameters representing sleep quality and disturbed breathing are estimated with high accuracies that are close to the results obtained by polysomnography. These unconstrained technologies, making sleep monitoring easier and simpler, will enhance qualities of life by expanding the range of ubiquitous healthcare.

Transferência de massa gás-líquido em coluna de aeração / Mass transfer gas-liquid in column of aeration

Neste trabalho estuda-se a transferência de massa gás-líquido a partir de bolhas de ar para a água, geradas por um difusor de ar, em uma coluna de aeração, mudando a vazão de ar de 400 L/h a 2000 L/h, o nível de água de 0,50 m a 1,80 m, cujas taxas de aplicação superficial de ar variaram de 3,1 L/m².s a 15,4 L/m².s. Várias características hidrodinâmicas foram medidas, tal como a velocidade ascensional das bolhas de ar e seus diâmetros, fundamentais para verificar o coeficiente de transferência de massa que estão na literatura, usando um equipamento laser para velocimetria não-intrusiva. Após os estudos da transferência de massa, foi concluído que a vazão de ar entre 400 L/h e 800 L/h e o nível de água de 1,80 m apresentou a maior eficiência de transferência de massa, garantindo para estas medidas, dentro da coluna em estudo, maior quantidade de oxigênio dissolvido.

The present work is a study of the mass transfer gas-liquid from air bubbles into water, generated by a diffuser of air, in a column of aeration, changing the air flow from 400 L/h to 2000 L/h, the level of water from 0.50 m to 1.80 m, whose taxes of superficial application of air had varied of 3.1 L/m².s to 15.4 L/m².s. Several hydrodynamics characteristics were measured, such as the velocity range of the air bubbles and their diameter, fundamental to check the mass transfer coefficient that are in literature, by using a laser equipment for non-intrusive velocimetry. After of the study of the mass transfer, it was concluded that the air flow between 400 L/h and 800 L/h and the level of water of 1.80 m was the most efficient of mass transfer, guaranteeing for these measure, into of the column in study, most quantity of dissolved oxygen.

Wearable Concurrent Monitoring System for Physiological Parameters / 航天医学与医学工程

Objective To design a wearable physiological monitoring system for acquiring and monitor-ing vital signs non-intrusively and concurrently.Methods All bio-sensors were embedded in an elastic shirt for detecting physiological parameters with wearable technology.A patented respiratory inductive plethysmography technology was used to measure respiratory function,two sensors were woven into the jerkin around the patient's chest and abdomen.A three-lead,single channel ECG measures heart rate,and a three-axis accelerometer records posture and activity level.An NTC thermometer embedded in the shirt measures the body temperature.Results An elastic jerkin with embedded sensors that collect and continuously monitor respiration,cardiac,temperature,posture and activity signals was fabricated.Conclusion This wearable physiological monitoring system can record multiple parameters non-intrusively and concurrently.It can act as an useful platform for further researches.

A System for Measurement of Pulse Wave Transit Time Continuously Based on Wireless Sensor Network / 航天医学与医学工程

Objective To design a system for monitoring pulse wave transit time (PWTT) in working condition non-intrusively and continuously. Method The system was composed of wireless ECG sensor and wireless pulse wave sensor which measure pulse wave signal from the temporal artery and ECG signal from body synchronously and calculates PWTT continuously. Result Both the wireless ECG sensor and the wireless pulse wave sensor were small sized and powered by button battery. And the accuracy of time synchronization about sensors was less than 1 ms. The calculated PWTT changed slowly with deep breathing. Conclusion The system works smoothly for continuous monitoring of PWTT in working condition.