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This paper proposes a novel regenerative braking control system of electric wheelchairs for senior citizen. ldquoElectric powered wheelchairrdquo, which generates the driving force by electric motors according to the human operation, is expected to be widely used as a mobility support system for elderly people. This study focuses on the braking control to realize the safety and smooth stopping motion...
Research of visual attention is one of the important domains of psychology and neurophysiology. In this study, an attention related electroencephalograph (EEG) signal processing method was proposed to distinguish the different levels of people's attention during the imaginary limbs motor. There were two EEG feedback experiments (playing tennis and walking) to measure the different levels of visual...
Electrical current is widely used to interact with or stimulate neural systems. Current transduction from device to tissue is mediated at the electrode-tissue interface by capacitive charge and electrochemistry. This charge-passing-capacity is frequency dependent. While safety parameters have been established for high-frequencies, safety has not been fully determined for novel materials and pulse...
A patient-specific model-based seizure detection method using statistically optimal null filters (SONF) has been recently proposed to aid the review of long-term EEG [1, 2]. The method relies on the model of a priori known seizure (template pattern) for subsequent detection of similar seizures. Artifacts, non-epileptic EEG rhythms, and at times modeling errors lead to increased false or missed detections...
The genes in NCBI databases are currently annotated with itemized text (Gene Reference Into Function, or GeneRIF). A previous work suggests that the visual presentation can be more effective when time and space are under heavy constraints. Here we report a novel annotation of the genome information using Web 2.0 technologies: GeneGIF (Gene Graphics Into Function). The users can quickly scan through...
Sepsis is characterized by profound cardiovascular abnormalities which may result from the derangements in the arterial baroreflex system and other autonomic regulatory functions. In this study, a mechanically ventilated and anesthetized rabbit model of endotoxic shock was utilized to mimic the behaviors of the cardiovascular system in a sepsis patient. 13 adult New Zealand white rabbits were studied,...
This paper presents a technique for assessing the performance of continuous wave Doppler radar systems for physiological sensing. The technique includes an artificial target for testing physiological sensing radar systems with motion analogous to human heart movement and software algorithms leveraging the capabilities of this target to simply test radar system performance. The mechanical target provides...
A time-varying parametric spectrum estimation method for analyzing dynamics of heart rate variability (HRV) signals is presented. In the method, HRV signal is first modeled with a time-varying autoregressive model and the model parameters are solved recursively with a Kalman smoother algorithm. Time-varying spectrum estimates are then obtained from the estimated model parameters. The obtained spectrum...
This paper presents the first clinical results for validating the accuracy of respiratory rate obtained for hospitalized patients using a non-contact, low power 2.4 GHz Doppler radar system. Twenty-four patients were measured in this study. The respiratory rate accuracy was benchmarked against the respiratory rate obtained using Welch Allyn Propaq Encore model 242, the Embla Embletta system with Universal...
Open loop linear parametric modeling approach was applied to describe the variability of the ventricular depolarization and repolarization duration (i.e. the QT interval from the ECG). Several model structures were compared. The model maximizing the goodness of fit describes the QT interval as a linear combination of its own past values plus two exogenous influences (i.e. heart period interval and...
AC component of photoplethysmography signal carries important information for diagnostics. Registered signal may be affected by noises, which are sharing the same bandwidth. Adaptive comb filter is used for the AC component extraction. Due to filter averaging behavior it decreases the signal shape difference between consecutive beats. Comb filter needs to be adjusted for PPG signal. Comb filter new...
The study of mechanomyographic (MMG) signals of respiratory muscles is a promising technique in order to evaluate the respiratory muscular effort. In this work MMG signals from left and right hemidiaphragm (MMGl and MMGr, respectively) acquired during a respiratory protocol have been analyzed. The acquisition of both MMG signals was carried out by means of two capacitive accelerometers placed on both...
Muscle fatigue is commonly associated with the musculoskeletal disorder problem. Previously, various techniques were proposed to index the muscle fatigue from electromyography signal. However, quantitative measurement is still difficult to achieve. This study aimed at proposing a method to estimate the degree of muscle fatigue quantitatively. A fatigue model was first constructed using handgrip dynamometer...
The successful use of implantable neural microelectrodes as neuroprosthetic devices depends on the mitigation of the reactive tissue response of the brain. One of the factors affecting the ultimate severity of the reactive tissue response and the in vivo electrical properties of the microelectrodes is the initial adsorption of proteins onto the surface of the implanted microelectrodes. In this study...
Our Bioengineering Research Partnership grant, ldquoHigh Frequency Ultrasound Arrays for Cardiac Imagingrdquo, including the individuals cited at the end of this paper - Douglas N. Stephens (UC Davis), Matthew O'Donnell (UW Seattle), Kai Thomenius (GE Global Research), Aaron M. Dentinger (GE Global Research), Douglas Wildes (GE Global Research), Peter Chen (St. Jude Medical), K. Kirk Shung (University...
The purpose of this study is to discuss the mechanism of brain injury experimentally, with respect to the pressure changes on the surface of a brain agar phantom by cavitation. First, an experimental system to perform an impact experiment is presented. We present some images taken by a high-speed camera of the behavior of a simple physical head model with and without the brain agar phantom during...
High frequency chest compression (HFCC) is used as a method to remove the mucus in the airway for cystic fibrosis (CF) patients. As the characteristics of the tracheal sound reflect the conditions of airways, in this paper, we propose a novel method to evaluate the respiratory patterns in HFCC therapy by using single channel tracheal sounds only. The difficulty of analyzing tracheal sounds lies in...
The design of an inductive power system is investigated in order to determine the relative benefits provided by the inclusion of a magnetic core in the receiver coil. Both transmitter and receiver coils are chosen to have dimensions similar to those used in many biomedical devices. It is found that while a magnetic core provides enhanced coupling, the operating frequency is limited by losses in the...
The majority of Brain Computer Interfaces have relied on signals related to primary motor cortex and the operation of the contralateral limb. Recently, the physiology associated with same-sided (ipsilateral) motor movements has been found to have a unique cortical physiology. This study sets out to assess whether more complex motor movements can be discerned utilizing ipsilateral cortical signals...
Modulation of pluripotent stem cell differentiation by several environmental factors, such as physical stimulation, is important theme in tissue engineering. In this study, we report the effects of extremely low frequency magnetic fields (ELF-MFs) exposure (1 mT or 10 mT, 50 Hz, sinusoidal) on the neuronal differentiation process of P19 embryonal carcinoma cells (P19 cells). Here, during induction...
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