Application of "Flipped Classroom" in comprehensive experiment teaching of Digital Signal Processing for biomedical engineering specialty / 中华医学教育探索杂志

"Flipped Classroom" is a new kind of "student-centered" teaching model, which can give full play to the advantages of both sides of teaching and learning. According to this teaching model, we redesigned the teaching process, in which the students studied by themselves and built their own knowledge system. Moreover, each of them took part in three stages of experimental design including digital signal collection, analysis and processing in groups. Results have shown that this model can fully stimulate students' learning interest, not only helps students to deepen understanding of digital signal processing theory knowledge, but also strengthen the ability of autonomous learning and team collaboration. The teaching model maybe have certain reference function in comprehensive experiment teaching of Digital Signal Processing course for biomedical engineering specialty.

Sincronización entre la videodeglución y la electromiografía de superficie en pacientes con afectación neurológica y síntomas de disfagia / Synchronization between videofluoroscopic swallowing study and surface electromyography in patients with neurological involvement presenting symptoms of dysphagia

Introducción. La disfagia se define como la dificultad para movilizar la comida desde la boca hasta el estómago. La prueba diagnóstica para esta condición es la videofluoroscopia, la cual no es totalmente inocua pues utiliza radiación ionizante. La electromiografía de superficie registra la actividad eléctrica de los músculos de manera no invasiva, por lo que puede considerarse como una alternativa para evaluar la deglución y estudiar la disfagia. Objetivo. Evaluar la relación entre los tiempos relativos de activación de los músculos implicados en la fase oral y faríngea de la deglución, con los movimientos registrados durante la videofluoroscopia. Materiales y métodos. Se analizaron las señales de la electromiografía de superficie de 10 pacientes neurológicos con síntomas de disfagia, captadas en forma simultánea con la videofluoroscopia. Se suministraron 5 ml de yogur y 10 ml de agua, y 3 g de galleta. Se estudiaron bilateralmente los grupos musculares maseteros, suprahioideos e infrahioideos. Se analizó el paso del bolo por la línea mandibular, las valleculas y el músculo cricofaríngeo, correlacionándolo con el tiempo inicial y el final de la activación de cada uno de los grupos musculares. Resultados. El tiempo promedio de la fase faríngea fue de 0,89 ± 0,12 s. En la mayoría de los casos, hubo activación muscular antes del paso por la línea mandibular y las valleculas. La terminación de la actividad muscular parece corresponder al momento en que se completa el paso del bolo alimenticio por el músculo cricofaríngeo. Conclusión. Se determinaron los tiempos de actividad muscular, la duración de la fase faríngea y la secuencia de la activación de los grupos musculares involucrados en la deglución, mediante electromiografía de superficie, validada con la videofluoroscopia.

Introduction: Dysphagia is defined as the difficulty in transporting food and liquids from the mouth to the stomach. The gold standard to diagnose this condition is the videofluoroscopic swallowing study. However, it exposes patients to ionizing radiation. Surface electromyography is a non-radioactive alternative for dysphagia evaluation that records muscle electrical activity during swallowing. Objective: To evaluate the relationship between the relative activation times of the muscles involved in the oral and pharyngeal phases of swallowing and the kinematic events detected in the videofluoroscopy. Materials and methods: Electromiographic signals from ten patients with neurological involvement who presented symptoms of dysphagia were analyzed simultaneously with videofluoroscopy. Patients were given 5 ml of yogurt, 10 ml of water, and 3 g of crackers. Masseter, suprahyoid, and infrahyoid muscle groups were studied bilaterally. The bolus transit through the mandibular line, vallecula, and the cricopharyngeus muscle was analyzed in relation to the onset and offset times of each muscle group activation. Results: The average time of the pharyngeal phase was 0.89 ± 0.12 s. Muscle activation was mostly observed prior to the bolus transit through the mandibular line and vallecula. The end of the muscle activity suggested that the passage of the bolus through the cricopharyngeus muscle was almost complete. Conclusion: The muscle activity times, duration of the pharyngeal phase, and sequence of the muscle groups involved in swallowing were determined using sEMG validated with the videofluoroscopic swallowing study.

Electroencephalogram signal analysis and its research progress in the field of epilepsy treatment / 中华神经科杂志

Epilepsy is a serious chronic neurological disorder that can be detected by analysing the brain signals generated by brain neurons, with electroencephalography (EEG) becoming a key tool in the diagnosis of epilepsy. The application of specific methods for processing and analysing EEG signals is important in exploring the working mechanisms of the brain and in the diagnosis of neurological disorders of the brain. The article describes the application of EEG signals in epilepsy treatment through feature extraction, feature classification and other related analysis methods. The article presents an overview of recent research advances through the use of principal component analysis, independent component analysis, wavelet transform, linear discriminant analysis, support vector machine, artificial neural network and decision tree. It provides some reference for the detection and classification of seizures and future research directions.

The design and implementation of power control circuit of ultrasonic scalpel based on DSP / 中国医学装备

Objective:To independently develop a power control system of ultrasonic scalpel so as to reduce the energy consumption and maintain the normal temperature of ultrasonic scalpel.Methods:In this paper, the model of equivalent circuit of ultrasonic transducer nearby syntony was built up, and the hardware control system of ultrasonic scalpel based on digital signal processing (DSP) was designed.Results:Through testing the circuit and work performance of power control system, the series of parameters such as effective value and so on which were produced by this system could adjust frequency of power source in time and attain anticipative functional indicator, and it took the ultrasonic scalpel to work in syntonic situation.Conclusion:The tested indicators of power control system of ultrasonic scalpel based on the kernel design of DSP can attain anticipative requirement, and can take this system to work in syntonic situation.

Monitoreo ambulatorio y generación de alertas tempranas ante anomalías cardiacas usando dispositivos móviles / Ambulatory monitoring and early warning generation of cardiac anomalies using mobile devices / Monitoramento ambulatorial e geração de aviso prévio de anomalias cardíacas usando dispositivos móveis

Resumen En este artículo se presenta un sistema portátil para el monitoreo ambulatorio del ritmo cardiaco y la detección temprana de las arritmias cardiacas de mayor riesgo. El sistema consta de un sensor con tres electrodos superficiales para la captura de la señal ECG, la cual se transmite vía Bluetooth a un dispositivo móvil con Android, en donde se realiza el análisis de la señal capturada durante lapsos de 5 s. El sistema propuesto distingue entre Ritmo Normal [Ritmo Sinusal - RS), Taquicardia Ventricular [TV), Fibrilación Ventricular [FV) y Asistolia, con una precisión del 100%, 55%, 75% y 90% respectivamente. Sin embargo, el sistema puede recuperarse de los errores rápidamente en el análisis de la trama subsecuente. Este trabajo se centra en el uso de dispositivos móviles de uso cotidiano, multitarea y de fácil acceso, implementando algoritmos en el dominio del tiempo para la extracción de parámetros, los cuales son idóneos para ser usados en aplicaciones móviles principalmente por su baja carga computacional y posibilidad de ejecución en tiempo real, permitiendo la detección de anomalías cardiacas de forma automática y rápida sin la necesidad de una supervisión constante por parte de un especialista para el análisis preliminar.

Abstract This paper presents a portable system for ambulatory heart rate monitoring and early detection of cardiac arrhythmias at high risk. The system consists of a sensor with three surface electrodes to capture the ECG signal, which is transmitted via bluetooth to a mobile device with Android, where the analysis is performed of the acquired signal during a time of 5 s. The proposed system distinguishes between Normal Rhythm [Rhythm Sinus - RS), Ventricular Tachycardia [VT), Ventricular Fibrillation [VF) and Asystole with an accuracy of 100%, 55%, 75% and 90% respectively. However, the system can quickly recover from errors in the subsequent analysis frame. This work focuses on using regular mobile devices which have multitasking and easy access characteristics, implementing algorithms in time domain for extracting parameters that are suitable to use in mobile applications, mainly because of their low computational load and possibility of execution in real time, allowing the detection of cardiac abnormalities automatically and quickly without the need of constant supervision by a specialist for preliminary analysis.

Resumo Neste artigo se apresenta um sistema portátil para o monitoramento da freqüência cardíaca ambulatorial e detecção precoce das arritmias cardíacas de mais risco. O sistema possui um sensor com três eletrodos superficiais para pegar o sinal ECG, o qual é transmitido via Bluetooth para um dispositivo móvel com Android, onde se faz a análise do sinal capturado durante um período de 5 s. O sistema proposto distingue entre Normal Ritmo [Ritmo Sinusal - RS), Taquicardia Ventricular [TV), Fibrilação Ventricular [FV) e Assistolia, com uma precisão do 100%, 55%, 75% e 90%, respectivamente. Porém, o sistema pode - se recuperar rapidamente dos erros na análise do quadro subsequente. Este trabalho centra-se no uso de dispositivos móveis de utilização diária, multitarefa e utilização acessível, implementação de algoritmos no domínio do tempo para a extração de parâmetros que são adequados para utilização em aplicações móveis, principalmente pela baixa carga computacional e possibilidade de execução em tempo real, permitindo a detecção de anormalidades cardíacas numa forma automática e rápida sem a necessidade de um controlo constante por um especialista para análise preliminar.

Differentiated teaching modes of course of digital signal processing for undergraduates and postgraduates / 医疗卫生装备

Objective To analyze the difference of teaching modes of course of digital signal processing for the undergraduates and postgraduates.Methods The teaching modes were compared from the aspects of educational objective,teaching content, teaching method,examination mode and etc.Results Differentiated teaching modes contributed to the satisfactory education of the undergraduates and postgraduates. Conclusion The differentiated teaching modes for the undergraduates and postgraduates provide references for the high-level education in universities and colleges of science and technology. [Chinese Medical Equipment Journal,2018,39(5):87-89,102]

Electrocardiogram Sampling Frequency Range Acceptable for Heart Rate Variability Analysis / 대한의료정보학회지

OBJECTIVES: Heart rate variability (HRV) has gained recognition as a noninvasive marker of autonomic activity. HRV is considered a promising tool in various clinical scenarios. The optimal electrocardiogram (ECG) sampling frequency required to ensure sufficient precision of R–R intervals for HRV analysis has not yet been determined. Here, we aimed to determine the acceptable ECG sampling frequency range by analyzing ECG signals from patients who visited an emergency department with the chief complaint of acute intoxication or overdose. METHODS: The study included 83 adult patients who visited an emergency department with the chief complaint of acute poisoning. The original 1,000-Hz ECG signals were down-sampled to 500-, 250-, 100-, and 50-Hz sampling frequencies with linear interpolation. R–R interval data were analyzed for time-domain, frequency-domain, and nonlinear HRV parameters. Parameters derived from the data on down-sampled frequencies were compared with those derived from the data on 1,000-Hz signals, and Lin's concordance correlation coefficients were calculated. RESULTS: Down-sampling to 500 or 250 Hz resulted in excellent concordance. Signals down-sampled to 100 Hz produced acceptable results for time-domain analysis and Poincaré plots, but not for frequency-domain analysis. Down-sampling to 50 Hz proved to be unacceptable for both time- and frequency-domain analyses. At 50 Hz, the root-mean-squared successive differences and the power of high frequency tended to have high values and random errors. CONCLUSIONS: A 250-Hz sampling frequency would be acceptable for HRV analysis. When frequency-domain analysis is not required, a 100-Hz sampling frequency would also be acceptable.

Design of magneto-acoustic-electrical detection system and verification of its linear sweep theory / 生物医学工程学杂志

Clinical studies had demonstrated that early diagnosis of lesion could significantly reduce the risk of cancer. Magneto-acoustic-electrical tomography (MAET) is expected to become a new detection method due to its advantages of high resolution and high contrast. Based on thinking of modular design, a low-cost, digital magneto-acoustic conductivity detection system was designed and implemented in this study. The theory of MAET using chirp continuous wave excitation was introduced. The results of homogeneous phantom experiment with 0.5% NaCl clearly showed that the conductivity curve of homogeneous phantom was highly consistent with the actual physical size, which indicated that the chirp excitation theory in our proposed system was correct and feasible. Besides, the resolution obtained by 1 000 μs sweep time was better than that obtained by 500 μs and 1 500 μs, which means that sweep time is an important factor affecting the detection resolution of the conductivity. The same result was obtained in the experiments carried out on homogeneous phantoms with different concentrations of NaCl, which demonstrated the repeatability of our proposed MAET system.

Análisis estadístico de los espectros de frecuencia de las regiones reguladoras del ENCODE / Statistical analysis of the Fourier Spectra of the ENCODE regulatory regions

RESUMEN En la actualidad, nuevas bases de datos genómicos (secuencias de ADN) son puestas al alcance del dominio público para su análisis. La bioinformática ha desarrollado algoritmos para extraer información y características de dichas secuencias. Sin embargo, estos algoritmos bioinformáticos tienen limitaciones. Una alternativa es utilizar herramientas propias del procesamiento digital de señales (DSP) adaptadas a secuencias genómicas (procesamiento de señales genómicas - GSP). El presente trabajo versa sobre el análisis de los cuatro primeros momentos centrales (media, desviación estándar, asimetría y curtosis) y dos momentos estadísticos (mediana y varianza) de los espectros frecuenciales de las 15 Regiones Reguladoras (RRs) de la base de datos ENCODE con el objetivo de estudiar diferencias estadísticas y frecuencias características. La base de datos seleccionada es "mapeada". Luego, la FFT es calculada a estas señales genómicas y finalmente los momentos estadísticos son implementados. Los resultados mues tran la existencia de 3 grupos de RRs utilizando la media, mediana y curtosis. La desviación estándar y la varianza, parecen no resaltar información importante. Finalmente, la asimetría revela un comportamiento homogéneo ante la presencia de valores atípicos en algunas RRs. Estas observaciones permiten inferir que la periodicidad dentro de la secuencia está relacionada o podría determinar la función biológica que desempeña la misma secuencia.

ABSTRACT Nowadays, new genomic databases (DNA sequences) are available to the whole scientist community for its analysis. The bioinformatics has developed algorithms to extract information and features of the sequences. However, the bioinformatics algorithms have restrictions. An alternative is the use of digital signal processing (DSP) tools adapted to genomic sequences (genomic signal processing - GSP). This work analyzes the first four statistics moments (mean, standard deviation, skewness and kurtosis) and other two moments (median and variance) of the frequency spectra of 15 regulatory regions (RRs) in ENCODE database with the main objective of studying the statistics di fferences and frequency features. The selected database is mapped. Then, the FFT is calculated to these genomic signals and finally the statistic moments implemented. The results show a three-group behavior in the RRs with the mean, median and kurtosis. The deviations standard and the variance do not show important behavior. Finally, the skewness shows a homogeneous behavior with the lack of atypical values in some RRs. These observations support the idea of the presence of periodicities in a sequence that may be related or may determine the biological function that a sequence may perform.

Clinical application value of MRI combined with DWI sequence in the diagnosis and follow-up of patients with meningioma / 重庆医学

Objective To explore the performance of meningiomas in MRI dynamic enhancement and DWI sequence,and to improve the accuracy of differential diagnosis of benign and malignant meningiomas.Methods Meningioma MRI data,which were pathology proved by the Guilin medical college affiliated hospital at different levels(Ⅰ,Ⅱ and Ⅲ),were retrospectively analyzed.The enhancement of meningiomas at all levels and the extent of edema were summarized,at the meantime the dynamic enhancement perfusion parameters and ADC values of meningioma MRI meningioma were contrastively analyzed.Results There were 30 cases of meningioma located in the brain falcus,27 cases of meningioma located in the sagittal sinus,10 cases of meningioma located in the cerebellopontine angle and 6 cases of meningioma located in other parts.The difference of ADC value between grade Ⅰ meningiomas and grade Ⅲ meningiomas was statistically significant different[(1.253±0.123)×10-3 mm2/s vs.(0.891±0.103)×10-3 mm2/s,P<0.05].The relative blood flow(rCBF)and relative blood volume(rCBV)of grade Ⅰ meningiomas were significantly lower than those of grade Ⅲ meningiomas(P<0.05).Conclusion MRI dynamic enhancement combined with DWI can accurately identify grade Ⅰ meningiomas and grade Ⅲ meningiomas,and it is necessary that the assessment of its classification should be appropriately considered to the higher level for patients who do not have a characteristic manifestation of meningioma in the preoperative.

A Trainable Hearing Aid Algorithm Reflecting Individual Preferences for Degree of Noise-Suppression, Input Sound Level, and Listening Situation

OBJECTIVES: In an effort to improve hearing aid users’ satisfaction, recent studies on trainable hearing aids have attempted to implement one or two environmental factors into training. However, it would be more beneficial to train the device based on the owner’s personal preferences in a more expanded environmental acoustic conditions. Our study aimed at developing a trainable hearing aid algorithm that can reflect the user’s individual preferences in a more extensive environmental acoustic conditions (ambient sound level, listening situation, and degree of noise suppression) and evaluated the perceptual benefit of the proposed algorithm. METHODS: Ten normal hearing subjects participated in this study. Each subjects trained the algorithm to their personal preference and the trained data was used to record test sounds in three different settings to be utilized to evaluate the perceptual benefit of the proposed algorithm by performing the Comparison Mean Opinion Score test. RESULTS: Statistical analysis revealed that of the 10 subjects, four showed significant differences in amplification constant settings between the noise-only and speech-in-noise situation (P<0.05) and one subject also showed significant difference between the speech-only and speech-in-noise situation (P<0.05). Additionally, every subject preferred different β settings for beamforming in all different input sound levels. CONCLUSION: The positive findings from this study suggested that the proposed algorithm has potential to improve hearing aid users’ personal satisfaction under various ambient situations.

Clinical study of custom abutment and digital provisional crown in implant denture gingival formation / 中国基层医药

Objective To analyze the effect of custom abutment and computer aided design and computer aided manufacturing(CAD/CAM) provisional crown on gingival shaping around the implant,and to research the main effect of the custom abutment in the formation of gingival.Methods According to the wishes of patients,fifteen patients were divided into two groups.Gingival molding used CAD/CAM in the observation group(n=7) to design and make custom abutment and provisional crown.The control group(n=8) used the prefabricated abutment and the hand-made self-curing resin temporary crown.Immediately after inserting of final insertion and three months later,pink esthetic score(PES) was calculated in both two groups.Results The labial gingiva curve of the observation group was (1.93±0.27)points,which was higher than (1.56±0.51)points of the control group,there was significant difference between the two groups(t=2.496,P0.05).The PES score of the observation group was (8.50±1.09)points,which was higher than (7.75±1.13)points of the control group,but the difference was not statistically significant(P>0.05).Conclusion The effect of the custom abutment on curvature of facial mucosa is significant.The combination of custom abutment and digital provisional crown can achieve better soft tissue stability and ideal aesthetic effect in a short time.

OpenSerum ­ Um Sistema Aberto de Monitoramento de Soro Hospitalar / OpenSerum - An Open Source System for Hospital Serum Monitoring / OpenSerum - Un Sistema Abierto de Monitoreo de Suero Hospitalaria

Objetivo: Este artigo apresenta o sistema de monitoramento de soro hospitalar OpenSerum. Trata-se de uma solução open source que faz uso de tecnologias de comunicação móvel para o acompanhamento em tempo real do serviço de infusão intravenosa de soro hospitalar. Método: Na primeira etapa, montou-se um circuito elétrico baseado em sensores infravermelhos para a monitoração da queda das gotas. Na segunda etapa, codificou-se um sistema servidor capaz de manter dados de configuração e enviar mensagens de texto informativas de status para dispositivos móveis cadastrados.  Resultados: O sistema de monitoramento permitiu detectar, por meio de mudanças na faixa de valores analógicos do receptor infravermelho, se o soro estava em atividade ou não. Conclusão: O sistema desenvolvido cumpriu com seus objetivos de monitoração, destacando a capacidade de interação com dispositivos móveis quando necessário para informar o status de atividade do soro monitorado.

Objectives: This paper presents the OpenSerum system for serum monitoring. It is an open source solution that uses mobile communication technologies for real-time monitoring of intravenous serum infusion service. Method: First, an electrical circuit was assembled based on infrared sensors in order to detect the fall of drops. Next, a server system was programed in order to maintain circuit configuration data and send textual messages with status information for mobile devices. Results: The monitoring system allows the detection, through changes in the range of analog infrared receiver values, whether the serum was active or not. Conclusion: The developed system reached its monitoring goals, highlighting the ability to interact with mobile devices when necessary to inform the serum activity status.

Objetivo: Ese artículo presenta el sistema de monitoreo de suero OpenSerum, una solución open source que hace uso de tecnologías de comunicación móviles para la monitorización en tiempo real de la infusión intravenosa de suero. Método: En la primera etapa, se creó un circuito eléctrico basado en sensores de infrarrojos para el seguimiento de la caída de las gotas. En la segunda, un sistema de servidor fue programado con el fin de mantener los datos de configuración de circuitos y enviar mensajes de texto con información de estado para dispositivos móviles. Resultados: El sistema de monitoreo permitió detectar por medio de cambios en la escala de valores analógicos del receptor infrarrojo, si el suero era o no en actividad. Conclusión: El sistema desarrollado cumplió con sus objetivos de monitoreo, poniendo de relieve la capacidad de interacción con dispositivos móviles cuando necesario para informar el status de actividad del suero.

Home e-Care: monitoramento de quedas em idosos através de smartwatches / Home e-Care: fall monitoring using smartwatches

Pessoas da terceira idade normalmente possuem a saúde mais frágil, elas ficam cada vez mais dependentes de ajuda na medida em que vão envelhecendo, principalmente na ocorrência de acidentes como quedas. Por esse motivo, torna-se necessário a existência de métodos automatizados de monitoramento e notificação da ocorrência de tais acidentes. OBJETIVO: Este trabalho apresenta uma metodologia para detecção automatizada de quedas em idosos, através do uso do acelerômetro presente em smartwatches com Android Wear e de detecção de quedas baseada em limiares. As ocorrências de queda são notificadas automaticamente para contatos de emergência. RESULTADOS: A aplicação criada alcançou resultados satisfatórios, obtendo 89,29% de especificidade, 75% de sensibilidade e 83,33% de acurácia. CONCLUSÃO: Concluiu-se que a abordagem adotada caracteriza uma alternativa robusta e viável para a detecção automatizada de quedas que contribui para a qualidade de vida para pessoas da terceira idade.

The elderly population is growing worldwide, and with that the concerns about their quality of life becomemore important. As the elderly normally have frail health, which tends to get worse as they age, they grow even more dependent on someone else, specifically in the event of an accident such as a fall. For that reason, an automated monitoring and notification mechanism for accidents is necessary. OBJECTIVE: This work aims to present an automated fall detection and notification methodology through the use of the android smartwatches embedded accelerometer andthreshold based algorithms. Notifications of falls will be sent to emergency contacts. RESULTS: The developed system reached satisfactory results, with 89,29% of specificity, 75% of recall and 83,33% of accuracy. CONCLUSION: We could observe that Home e-Care and the TBA are a robust and viable solution for automated fall detection, and can improve the elderly's quality of life.

Evaluation of MRI for axillary lymph node in breast cancer after neoadjuvant chemotherapy / 天津医药

Objective To explore and evaluate the clinical value of MRI for status of axillary lymph node after neoadju-vant chemotherapy (NAC) in patients with breast cancer. Methods Forty-four patients with 1ocally advanced breast cancer (LABC) were underwent NAC for four cycles. The longest diameter of axillary lymph node (ALN) measured by MRI scan. Val-ue of apparent diffusion coefficient (ADC) and their correlation were compared before NAC and four cycles after NAC. Re-sults of MRI and pathological data for ALN were compared between two groups of patients. Results All patients finished four cycles of NAC. The total response rate (CR+PR) was 72.7% (32/44), and the total non-response rate (SD+PD) was 27.3%(12/44). The longest diameter of ALN was significantly shortened in response group. The longest diameter was (1.37± 1.06) cm before NAC and (0.90±0.76) cm after NAC (P<0.01). The ADC value of the tumor was significantly increased in re-sponse group [(0.91±0.28) ×10-3 mm2/s before NAC and (1.01±0.32)×10-3 mm2/s after NAC, P<0.01)]. There was no signifi-cant correlation between ADC value change (△ADC) and the longest diameter change of ALN (△L, r=0.131, P=0.413). The sensitivity, specificity and Kappa value of ALN evaluation after NAC were 100%, 62.5%and 0.68 measured by MRI. Con-clusion The change of tumor longest diameter reflects the effect of chemotherapy directly. The tumor ADC value of MRI can not be used as an independent indicator of chemotherapy effect of ALN, eventhouth MRI was the sensitive index for eval-uating the status of axillary lymph node after neoadjuvant chemotherapy for breast cancer.

Recognition of heart sound based on distribution of Choi-Williams

IntroductionTo realize noninvasive diagnosis and early diagnosis of coronary heart disease, the study proposes a new time-frequency method for analyzing heart sound signals. This method is based on Choi-Williams Distribution (CWD).MethodsCWD distribution is developed and modified from Wigner Ville distribution (WVD). To solve the problem of cross-term interference existing in WVD there is an improved version of WVD, called Choi-Williams Distribution (CWD), which introduces the smoothing window as the kernel function and deals with the time-frequency analysis of heart sound signal.ResultsThe improved method has good performance and can be implemented simply without much increase of operation complexity.ConclusionIn this paper, 21 cases of heart sound signals are acquired from the outpatients and hospitalized patients with coronary heart diseases. The research results of 21 cases show that the CWD method can be used to analyze heart sounds. It accurately identifies the 9 cases of heart sounds of health people and 12 cases of heart sounds of patients with coronary heart disease. Besides, the CWD displays obvious differences between heart sounds of healthy people and abnormal heart sounds. The contour line of heart sounds from healthy people shows the following characteristics: concise, columnar and non-divergence; while the contour line of abnormal heart sounds is divergent and has many columnar links. These research shows that CWD method can effectively distinguish heart sounds between healthy people and patients with coronary heart disease.

MÉTODO ALTERNATIVO DE CONTROL DE INTENSIDAD LUMÍNICA PARA PULSIOXIMETRÍA EN TIEMPO REAL / AN ALTERNATIVE METHOD FOR POWER CONTROL OF LUMINICINTENSITY IN PULSEOXIMETRY ON REAL TIME / MÉTODO ALTERNATIVO DE CONTROLE DE INTENSIDADE DALUZ PARÁGRAFO OXIMETRIATEMPO REAL

El pulsioxímetro es una herramienta no invasiva esencial para el monitoreo de la saturación arterial de oxígeno. Utiliza la espectrofotometría para detectar sobre la piel dos intensidades de luz (600 y 900 nm) que proporcionan información de la perfusión tisular y cantidad de oxígeno transportada. Depende de un circuito de manipulación de corriente, dos diferentes fuentes emisoras de luz, un foto-detector y una unidad de procesamiento que permiten ajustar las intensidades de luz ante tejidos de diferentes características. En el presente trabajo, se propone un método de modulación por ancho de pulso alternativo para el control de la intensidad lumínica media, cuyo principio es la conmutación on/off de la corriente aplicada a los LEDs en la etapa de emisión. Este sistema permite modificar tanto el nivel de CD como la amplitud de la señal de CA de la onda fotopletismográfica e implica la reducción del número de componentes analógicos y consumo de energía. La metodología presentada permite regular la resolución de la señal muestreada y ofrece disminuciones del 21 % y 40 % en potencia comparado con los esquemáticos propuestos por Freescale Semiconductor, Inc. y Texas Instruments Incorporated respectivamente. El uso de señales sincronizadas moduladas en ancho de pulso con frecuencias por encima de 333 kHz y pasos de 50 ns para emitir luz, permitió una reducción 41% de potencia, respecto al sistema con modulación analógica del módulo MDK pulse oximeter.

Pulse oximetry is an essential optical based non-invasive tool for monitoring blood oxygen saturation. It uses spectrophotometry to detect two light intensities (600 and 900 nm) through the skin; it provides information on tissue perfusion and quantity of transported oxygen. The process relies on a current control circuit, two light emitting sources, a photodetector, and a digital signal processor that adjusts the light intensities for different tissue characteristics. This paper proposes an alternative method of pulse width modulation for controlling the mean light intensity level, whose principle is a pulse width nodulation of the current applied to the LEDs in the emitting stage. This system allows modifying the DC level and the amplitude of the AC signal of the photopletismographic wave. The results is the reduction of the number of analog components and power consumption. The methodology presented, it allows adjusting the definition of the sample signal and offers power reductions of 21% and 40% compared to schematics given by Freescale Semiconductor, Inc. and Texas Instruments Incorporated, respectively. Thus, by using synchronized signal pulse width modulation to emit light, with frequencies above 333 kHz and steps of 50 ns, it will allow power reductions of 41%, compared to the conventional analog modulation module MDK pulse oximeter.

O oxímetro de pulso é uma ferramenta não invasiva essencial para o monitoramento da saturação de oxigênio no sangue. Usa espectrofotometria para detectar a pele duas intensidades de luz (600 nm e 900) para fornecer informações de perfusão tecidual ea quantidade de oxigênio transportado. Depende de manuseamento corrente do circuito, duas fontes diferentes emissores de luz, um fotodetector e uma unidade de processamento para ajustar a intensidade da luz nos tecidos com características diferentes. Neste trabalho, um método de modulação de largura de pulso alternativa para controlar a intensidade de luz média, o princípio é o de ligar/desligar da corrente aplicada aos LEDs no palco questão é proposto. Este sistema permite modificar tanto o nível DC e a amplitude do sinal AC da forma de onda fotoplestimográfico e envolve a redução do número de componentes analógicos e consumo de energia. A metodologia apresentada permite ajustar a resolução do sinal de amostragem e oferece reduções de 21% e 40% da potência em comparação com o esquema proposto pela Freescale Semicondutor, Inc. e Texas Instruments Incorporated, respectivamente. Sinais sincronizados usando freqüências moduladas por largura de pulso acima de 333 kHz e 50 ns passos para emitir luz, permitiu uma redução de 41% de energia em comparação com módulo de oxímetro de pulso MDK sistema de modulação analógica.

Drowsiness detection for single channel EEG by DWT best m-term approximation

Introduction In this paper we propose a promising new technique for drowsiness detection. It consists of applying the best m-term approximation on a single-channel electroencephalography (EEG) signal preprocessed through a discrete wavelet transform. Methods In order to classify EEG epochs as awake or drowsy states, the most significant m terms from the wavelet expansion of an EEG signal are selected according to the magnitude of their coefficients related to the alpha and beta rhythms. Results By using a simple thresholding strategy it provides hit rates comparable to those using more complex techniques. It was tested on a set of 6 hours and 50 minutes EEG drowsiness signals from PhysioNet Sleep Database yielding an overall sensitivity (TPR) of 84.98% and 98.65% of precision (PPV). Conclusion The method has proved itself efficient at separating data from different brain rhythms, thus alleviating the requirement for complex post-processing classification algorithms.

An algorithm of real-time peak detection for pulse signals based on FPGA / 军事医学

Objective To present a new algorithm of real-time peak detection for pulse signals based on FPGA , which is known as the dynamic threshold with half peak detection method ( DT-HP ) .Methods With Gaussian-shaped pulse signals as the target , the method was improved from conventional methods .The FPGA detection process of the algorithm required no more than three detection parameters: the starting point , the maximum value and the pulse width .Results The algorithm solved the floating baseline and repeating detection that occur in traditional methods .Compared with the results of polynomial fitting method and flow cytometry , the difference was only 3.2% and 9.3%.Conclusion The algorithm takes less time ,RAM, and cache while allowing floating baseline detection , which can be used as an effective method for rapid detection in FPGA .

Effects of the Simultaneous Application of Nonlinear Frequency Compression and Dichotic Hearing on the Speech Recognition of Severely Hearing-Impaired Subjects: Simulation Test

OBJECTIVES: The clinical effects of the simultaneous application of nonlinear frequency compression and dichotic hearing on people with hearing impairments have not been evaluated previously. In this study, the clinical effects of the simultaneous application of these two techniques on the recognition of consonant-vowel-consonant (CVC) words with fricatives were evaluated using normal-hearing subjects and a hearing loss simulator operated in the severe hearing loss setting. METHODS: A total of 21 normal-hearing volunteers whose native language was English were recruited for this study, and two different hearing loss simulators, which were configured for severe hearing loss in the high-frequency range, were utilized. The subjects heard 82 English CVC words, and the word recognition score and response time were measured. RESULTS: The experimental results demonstrated that the simultaneous application of these two techniques showed almost even performance compared to the sole application of nonlinear frequency compression in a severe hearing loss setting. CONCLUSION: Though it is generally accepted that dichotic hearing can decrease the spectral masking thresholds of an hearing-impaired person, simultaneous application of the nonlinear frequency compression and dichotic hearing techniques did not significantly improve the recognition of words with fricatives compared to the sole application of nonlinear frequency compression in a severe hearing loss setting.