Alberto J. Molina

A Method of EOG Signal Processing to Detect the Direction of Eye Movements

In this paper, a signal processing algorithm to detect eye movements is developed. The algorithm works with two kinds of inputs: derivative and amplitude level of electrooculographic signal. Derivative is used to detect signal edges and the amplitude level is used to filter noise. Depending of movement direction, different kinds of events are generated. Events are associated with a movement and its route. A hit rate equal to 94% is reached. This algorithm has been used to implement an application that allows computer control using ocular movement.

Envelopment filter and K-means for the detection of QRS waveforms in electrocardiogram.

The electrocardiogram (ECG) is a well-established technique for determining the electrical activity of the heart and studying its diseases. One of the most common pieces of information that can be read from the ECG is the heart rate (HR) through the detection of its most prominent feature: the QRS complex. This paper describes an offline version and a real-time implementation of a new algorithm to determine QRS localization in the ECG signal based on its envelopment and K-means clustering algorithm. The envelopment is used to obtain a signal with only QRS complexes, deleting P, T, and U waves and baseline wander. Two moving average filters are applied to smooth data. The K-means algorithm classifies data into QRS and non-QRS. The technique is validated using 22 h of ECG data from five Physionet databases. These databases were arbitrarily selected to analyze different morphologies of QRS complexes: three stored data with cardiac pathologies, and two had data with normal heartbeats. The algorithm has a low computational load, with no decision thresholds. Furthermore, it does not require any additional parameter. Sensitivity, positive prediction and accuracy from results are over 99.7%.

Dispersion relations in the nuclear optical model

We have developed a code to calculate integrals arising from the dispersion relation between the real and the imaginary parts of the nuclear optical model potential (OMP). Both, analytical solution for the most common dispersive OMP, and the general numerical solution, are included. In the numerical integration, fast convergence is achieved by means of the Gauss–Legendre integration method, which offers accuracy, easiness of implementation and generality for dispersive optical model calculations. The numerical method is validated versus analytical solution. The use of this package in the OMP parameter search codes allows for an efficient and accurate dispersive analysis.  2003 Elsevier Science B.V. All rights reserved.

A general numerical solution of dispersion relations for the nuclear optical model

A general numerical solution of the dispersion integral relation between the real and the imaginary parts of the nuclear optical potential is presented. Fast convergence is achieved by means of the Gauss-Legendre integration method, which offers accuracy, ease of implementation and generality for dispersive optical model calculations. The use of this numerical integration method in the optical model parameter search codes allows for a fast and accurate dispersive analysis.

One way of bringing final year computer science student world to the world of children with cerebral palsy: a case study

In this paper, a learning project is explained which is being carried out at the school of computer science at the University of Seville. The aim is that students receive knowledge of assistive technologies when in fact there is no this discipline in our curricula. So the best way, it is programming final studies projects in this field. We want to make the projects have a real application and can solve difficulties that children with Cerebral Palsy have in their daily activities in the school.

A new multisensor software architecture for movement detection: Preliminary study with people with cerebral palsy

Abstract A five-layered software architecture translating movements into mouse clicks has been developed and tested on an Arduino platform with two different sensors: accelerometer and flex sensor. The architecture comprises low-pass and derivative filters, an unsupervised classifier that adapts continuously to the strength of the users movements and a finite state machine which sets up a timer to prevent involuntary movements from triggering false positives. Four people without disabilities and four people with cerebral palsy (CP) took part in the experiments. People without disabilities obtained an average of 100% and 99.3% in precision and true positive rate (TPR) respectively and there were no statistically significant differences among type of sensors and placement. In the same experiment, people with disabilities obtained 97.9% and 100% in precision and TPR respectively. However, these results worsened when subjects used the system to access a communication board, 89.6% and 94.8% respectively. With their usual method of access-an adapted switch- they obtained a precision and TPR of 86.7% and 97.8% respectively. For 3-out-of-4 participants with disabilities our system detected the movement faster than the switch. For subjects with CP, the accelerometer was the easiest to use because it is more sensitive to gross motor motion than the flex sensor which requires more complex movements. A final survey showed that 3-out-of-4 participants with disabilities would prefer to use this new technology instead of their traditional method of access.

Customizable software interface for monitoring applications

In this paper we propose an application based on virtual keyboard and automatic scanning to communicate with a PC and the others people. The aim users are the people with disabilities. A high degree of customization is possible in the software. So the user can selected the color of buttons, position of system on screen, the kind of scanning, timer, the interface of communication, etc. Five people without disabilities tested our system. The results of the tests show the application reduce the fatigue of user and increased the text entry rate.

The Role of Small Robots in Designed Play Workshops in Centers of Adults with Cerebral Palsy

An experience that took place in ASPACE (Association of People with Cerebral Palsy in Seville) showed that the intervention with games based on tangible devices like small robots is a good alternative in the case of people with cerebral palsy (CP). The aim is to develop skills in three facets: cognitive, motor and social. From three to six sessions with seven subjects allowed obtaining information on the evolution of them and their involvement in the activity.

Envelope filter sequence to delete blinks and overshoots.

BackgroundEye movements have been used in control interfaces and as indicators of somnolence, workload and concentration. Different techniques can be used to detect them: we focus on the electrooculogram (EOG) in which two kinds of interference occur: blinks and overshoots. While they both draw bell-shaped waveforms, blinks are caused by the eyelid, whereas overshoots occur due to target localization error and are placed on saccade. They need to be extracted from the EOG to increase processing effectiveness.MethodsThis paper describes off- and online processing implementations based on lower envelope for removing bell-shaped noise; they are compared with a 300-ms-median filter. Techniques were analyzed using two kinds of EOG data: those modeled from our own design, and real signals. Using a model signal allowed to compare filtered outputs with ideal data, so that it was possible to quantify processing precision to remove noise caused by blinks, overshoots, and general interferences. We analyzed the ability to delete blinks and overshoots, and waveform preservation.ResultsOur technique had a high capacity for reducing interference amplitudes (>97%), even exceeding median filter (MF) results. However, the MF obtained better waveform preservation, with a smaller dependence on fixation width.ConclusionsThe proposed technique is better at deleting blinks and overshoots than the MF in model and real EOG signals.

The Possibilities of Kinect as an Access Device for People with Cerebral Palsy - A Preliminary Study.

Cerebral palsy (CP) is a general term for a group of permanent, non-progressive movement disorders that cause physical disability in development, mainly in the areas of body movement but it might also affect intellectual capabilities. Among all this diversity of profiles, we find that, for some of them, access to a computer application is almost impossible in spite of the great variety of commercial devices based of different technologies. Kinect might be a viable possibility in order to facilitate access to games and computer applications that help users improve their skills or communication.