Ignacio Rojas

Bio: Ignacio Rojas is an academic researcher from University of Granada. The author has contributed to research in topics: Fuzzy logic & Fuzzy control system. The author has an hindex of 36, co-authored 321 publications receiving 5459 citations. Previous affiliations of Ignacio Rojas include ETH Zurich & Helsinki University of Technology.

Window Size Impact in Human Activity Recognition

Abstract: Signal segmentation is a crucial stage in the activity recognition process; however, this has been rarely and vaguely characterized so far. Windowing approaches are normally used for segmentation, but no clear consensus exists on which window size should be preferably employed. In fact, most designs normally rely on figures used in previous works, but with no strict studies that support them. Intuitively, decreasing the window size allows for a faster activity detection, as well as reduced resources and energy needs. On the contrary, large data windows are normally considered for the recognition of complex activities. In this work, we present an extensive study to fairly characterize the windowing procedure, to determine its impact within the activity recognition process and to help clarify some of the habitual assumptions made during the recognition system design. To that end, some of the most widely used activity recognition procedures are evaluated for a wide range of window sizes and activities. From the evaluation, the interval 1-2 s proves to provide the best trade-off between recognition speed and accuracy. The study, specifically intended for on-body activity recognition systems, further provides designers with a set of guidelines devised to facilitate the system definition and configuration according to the particular application requirements and target activities.

mHealthDroid: A Novel Framework for Agile Development of Mobile Health Applications

Abstract: Mobile health is an emerging field which is attracting much attention. Nevertheless, tools for the development of mobile health applications are lacking. This work presents mHealthDroid, an open source Android implementation of a mHealth Framework designed to facilitate the rapid and easy development of biomedical apps. The framework is devised to leverage the potential of mobile devices like smartphones or tablets, wearable sensors and portable biomedical devices. The framework provides functionalities for resource and communication abstraction, biomedical data acquisition, health knowledge extraction, persistent data storage, adaptive visualization, system management and value-added services such as intelligent alerts, recommendations and guidelines.

Design, implementation and validation of a novel open framework for agile development of mobile health applications.

Abstract: The delivery of healthcare services has experienced tremendous changes during the last years. Mobile health or mHealth is a key engine of advance in the forefront of this revolution. Although there exists a growing development of mobile health applications, there is a lack of tools specifically devised for their implementation. This work presents mHealthDroid, an open source Android implementation of a mHealth Framework designed to facilitate the rapid and easy development of mHealth and biomedical apps. The framework is particularly planned to leverage the potential of mobile devices such as smartphones or tablets, wearable sensors and portable biomedical systems. These devices are increasingly used for the monitoring and delivery of personal health care and wellbeing. The framework implements several functionalities to support resource and communication abstraction, biomedical data acquisition, health knowledge extraction, persistent data storage, adaptive visualization, system management and value-added services such as intelligent alerts, recommendations and guidelines. An exemplary application is also presented along this work to demonstrate the potential of mHealthDroid. This app is used to investigate on the analysis of human behavior, which is considered to be one of the most prominent areas in mHealth. An accurate activity recognition model is developed and successfully validated in both offline and online conditions.

Prenatal detection of velamentous insertion of the umbilical cord: a prospective color Doppler ultrasound study

Abstract: Objective Velamentous insertion of the umbilical cord, with a reported incidence of 1% in singleton pregnancies, has been associated with several obstetric complications including fetal growth restriction, prematurity, congenital anomalies, low Apgar scores, fetal bleeding and retained placenta. The aim of this study was to determine the feasibility of identifying velamentous insertion of the umbilical cord during routine obstetric ultrasound. Design This was a prospective, cross-sectional ultrasound study in 832 unselected second- and third-trimester singleton pregnancies. Color Doppler ultrasound was routinely performed to identify the placental cord insertion site. The role of three-dimensional (3D) ultrasound in evaluating the placental cord insertion site was also studied in a subset of 50 pregnancies from this population. Results The placental cord insertion site was identified in 825/832 (99%) cases. Visualization was not achieved in seven third-trimester pregnancies with a posterior placenta. A velamentous insertion was suspected prenatally in eight cases, seven of which were confirmed after delivery as velamentous and one as markedly eccentric (battledore placenta). 3D ultrasound performed poorly at evaluating placental cord insertion site, being less efficient due to poor-quality resolution and far more time-consuming than the combined use of gray-scale and color Doppler ultrasound. Conclusions Velamentous insertion of the umbilical cord can reliably be detected prenatally by gray-scale and color Doppler ultrasound. 3D imaging had limited value in the evaluation of the placental cord insertion site in our subset of patients. Systematic assessment of the placental cord insertion site at routine obstetric ultrasound has the potential of identifying pregnancies with velamentous insertion and, therefore, those at risk for obstetric complications including vasa previa. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Medscape

Abstract: Secret History: Return of the Black Death Channel 4, 7-8pm In 1348 the Black Death swept through London, killing people within days of the appearance of their first symptoms. Exactly how many died, and why, has long been a mystery. This Secret History documentary follows experts as they pick through the evidence and reveal why the plague killed on such a scale. And they ask, what might be coming next?

The Self-Organizing Map

Abstract: An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.