S-EMG Signal Compression in One-Dimensional and Two-Dimensional Approaches.

This paper presents algorithms designed for one-dimensional (1-D) and 2-D surface electromyographic (S-EMG) signal compression. The 1-D approach is a wavelet transform based encoder applied to isometric and dynamic S-EMG signals. An adaptive estimation of the spectral shape is used to carry out dynamic bit allocation for vector quantization of transformed coefficients.

The behavior of action potential conduction velocity on isokinetic knee extension tests.

The present study investigates the behavior of action potential conduction velocity (CV) on each repetition of an isokinetic test set and on each set as a whole. A total of seven healthy men (27.7 ± 2.

Semi-automatic algorithm for construction of the left ventricular area variation curve over a complete cardiac cycle.

Background: Two-dimensional echocardiography (2D-echo) allows the evaluation of cardiac structures and their movements. A wide range of clinical diagnoses are based on the performance of the left ventricle. The evaluation of myocardial function is typically performed by manual segmentation of the ventricular cavity in a series of dynamic images.

Two-dimensional compression of surface electromyographic signals using column-correlation sorting and image encoders.

We present a new preprocessing technique for two-dimensional compression of surface electromyographic (S-EMG) signals, based on correlation sorting. We show that the JPEG2000 coding system (originally designed for compression of still images) and the H.264/AVC encoder (video compression algorithm operating in intraframe mode) can be used for compression of S-EMG signals.

On the use of motion-based frame rejection in temporal averaging denoising for segmentation of echocardiographic image sequences.

We have recently introduced an algorithm for semi-automatic segmentation of the left ventricular wall in short-axis echocardiographic images (EMBC 30:218-221). In its preprocessing stage, the algorithm uses temporal averaging for image denoising. Motion estimation is used to detect and reject frames that do not correlate well with the set of images being averaged.

Isokinetic work-to-surface electromyographic signal energy ratios as a muscular fatigue indicator.

Efficiency of muscular work is usually measured as the relationship between work load and maximum exercise duration. The present study analyzes the efficiency feature as a ratio between mechanical work (WK) and the energy (E) of the surface electromyographic signal (SEMG). This relation (WK/E(SEMG)) was compared with the most common electromyographic descriptors and its behavior was observed during muscle fatigue.

Surface EMG and spatial resolution analysis with estimation of electromyographic descriptors.

Spatial filtering has become a common way to improve the resolution of surface electromyographic signals (SEMG) when used in connection with electrode arrays. The goal of this study is to observe the behavior of S-EMG amplitude and spectral descriptors when signals are submitted to a longitudinal quadruple differentiating spatial filter. Signals were acquired at 20% and 60% of the maximum voluntary contraction using a linear array of eight surface electrodes in order to understand the impact of the filtering technique in the S-EMG variables during fatiguing and non-fatiguing contractions.

Energy efficient simulator for patient monitoring in Body Sensor Networks.

The medical tracking of patients carried out from a distance by means of wireless technology, incorporating various sensors simultaneously connected to the body of an individual, can promote health in suitable time. This article proposes a simulator for the monitoring of human health. This prototype simulates the workings of a BSN (Body Sensor Network) functioning as a sensor (electrophysiological signal) that is to be monitored, which utilizes a strategy based on the concept of data fusion.

Semi-automatic detection of the left ventricular border.

Two semi-automatic methods for the detection of the left ventricular border in two-dimensional short axis echocardiographic images are presented and compared. In these methods, the left ventricular area variation curve is calculated during a complete cardiac cycle after the segmentation of several frames. This allows the evaluation of the cardiovascular dynamics and the identification of important clinical parameters.

An instrument to measure the convective heat transfer coefficient on large vessels.

Hepatocellular carcinoma is one of the most common malignancies worldwide. During radiofrequency hepatic ablation, the tumor is heated by means of radiofrequency energy. The heating causes necrosis of the malignant tumor.

A new biomechanical hand prosthesis controlled by surface electromyographic signals.

This paper describes the development of a low-cost hand prosthesis for use in patients with an amputated hand due to congenital problems or to trauma wound, who possess a part or the forearm endowed with muscular activity. The paper covers the constructive aspects of both mechanical and electronic designs. The prototype is controlled by electromyographic signals measured at the remaining part of the injured limb of the patient.

A new wavelet-based algorithm for compression of EMG signals.

Despite the growing interest in the transmission and storage of electromyographic signals for long periods of time, only a few studies dealt with the compression of these signals. In this article we propose a novel algorithm for EMG signal compression using the wavelet transform. For EMG signals acquired during isometric contractions, the proposed algorithm provided compression factors ranging from 50 to 90%, with an average PRD ranging from 1.

A new model for programming software in body sensor networks.

A Body Sensor Network (BSN) must be designed to work autonomously. On the other hand, BSNs need mechanisms that allow changes in their behavior in order to become a clinically useful tool. The purpose of this paper is to present a new programming model that will be useful for programming BSN sensor nodes.

Effects of the time response of the temperature sensor on thermodilution measurements.

Thermodilution is widely used to measure cardiac output, ejection fraction and end diastolic volume. Even though the method is based on dynamic temperature measurements, little attention has been paid to the characterization of the dynamic behavior of the temperature sensor and to its influence on the accuracy of the method. This paper presents several theoretical and empirical results related to the thermodilution method.