A Motion compensated filtering approach to remove sunlight flicker in shallow water images

A common problem in video surveys in very shallow waters is the presence of strong light fluctuations, due to sun light refraction. Refracted sunlight casts fast moving patterns, which can significantly degrade the quality of the acquired data. Motivated by the growing need to improve the quality of shallow water imagery, we propose a method to remove sunlight patterns in video sequences. The method exploits the fact that video sequences allow several observations of the same area of the sea floor, over time. It is based on computing the image difference between a given reference frame and the temporal median of a registered set of neighboring images. A key observation is that this difference will have two components with separable spectral content. One is related to the illumination field (lower spatial frequencies) and the other to the registration error (higher frequencies). The illumination field, recovered by lowpass filtering, is used to correct the reference image. In addition to removing the sunflickering patterns, an important advantage of the approach is the ability to preserve the sharpness in corrected image, even in the presence of registration inaccuracies. The effectiveness of the method is illustrated in image sets acquired under strong camera motion containing non-rigid benthic structures. The results testify the good performance and generality of the approach

Adaptive intelligent agent approach to guide the web navigation on the PLAN-G distance learning platform

Hypermedia systems based on the Web for open distance education are becoming increasingly popular as tools for user-driven access learning information. Adaptive hypermedia is a new direction in research within the area of user-adaptive systems, to increase its functionality by making it personalized [Eklu 961. This paper sketches a general agents architecture to include navigational adaptability and user-friendly processes which would guide and accompany the student during hislher learning on the PLAN-G hypermedia system (New Generation Telematics Platform to Support Open and Distance Learning), with the aid of computer networks and specifically WWW technology [Marz 98-1] [Marz 98-2]. The PLAN-G actual prototype is successfully used with some informatics courses (the current version has no agents yet). The propased multi-agent system, contains two different types of adaptive autonomous software agents: Personal Digital Agents {Interface), to interacl directly with the student when necessary; and Information Agents (Intermediaries), to filtrate and discover information to learn and to adapt navigation space to a specific student

A new approach to segmentation based on fusing circumscribed contours, region growing and clustering

One of the major problems in machine vision is the segmentation of images of natural scenes. This paper presents a new proposal for the image segmentation problem which has been based on the integration of edge and region information. The main contours of the scene are detected and used to guide the posterior region growing process. The algorithm places a number of seeds at both sides of a contour allowing stating a set of concurrent growing processes. A previous analysis of the seeds permits to adjust the homogeneity criterion to the regions's characteristics. A new homogeneity criterion based on clustering analysis and convex hull construction is proposed

A new approach to the classification of mammographic masses and normal breast tissue

A new approach to mammographic mass detection is presented in this paper. Although different algorithms have been proposed for such a task, most of them are application dependent. In contrast, our approach makes use of a kindred topic in computer vision adapted to our particular problem. In this sense, we translate the eigenfaces approach for face detection/classification problems to a mass detection. Two different databases were used to show the robustness of the approach. The first one consisted on a set of 160 regions of interest (RoIs) extracted from the MIAS database, being 40 of them with confirmed masses and the rest normal tissue. The second set of RoIs was extracted from the DDSM database, and contained 196 RoIs containing masses and 392 with normal, but suspicious regions. Initial results demonstrate the feasibility of using such approach with performances comparable to other algorithms, with the advantage of being a more general, simple and cost-effective approach

A new approach to real time traffic sign recognition based on colour information

The automatic interpretation of conventional traffic signs is very complex and time consuming. The paper concerns an automatic warning system for driving assistance. It does not interpret the standard traffic signs on the roadside; the proposal is to incorporate into the existing signs another type of traffic sign whose information will be more easily interpreted by a processor. The type of information to be added is profuse and therefore the most important object is the robustness of the system. The basic proposal of this new philosophy is that the co-pilot system for automatic warning and driving assistance can interpret with greater ease the information contained in the new sign, whilst the human driver only has to interpret the "classic" sign. One of the codings that has been tested with good results and which seems to us easy to implement is that which has a rectangular shape and 4 vertical bars of different colours. The size of these signs is equivalent to the size of the conventional signs (approximately 0.4 m2). The colour information from the sign can be easily interpreted by the proposed processor and the interpretation is much easier and quicker than the information shown by the pictographs of the classic signs

An approach to visual servoing based on coded light

Positioning a robot with respect to objects by using data provided by a camera is a well known technique called visual servoing. In order to perform a task, the object must exhibit visual features which can be extracted from different points of view. Then, visual servoing is object-dependent as it depends on the object appearance. Therefore, performing the positioning task is not possible in presence of non-textured objects or objects for which extracting visual features is too complex or too costly. This paper proposes a solution to tackle this limitation inherent to the current visual servoing techniques. Our proposal is based on the coded structured light approach as a reliable and fast way to solve the correspondence problem. In this case, a coded light pattern is projected providing robust visual features independently of the object appearance

An LMI approach to H∞ synchronization of second-order neutral master-slave systems

The H∞ synchronization problem of the master and slave structure of a second-order neutral master-slave systems with time-varying delays is presented in this paper. Delay-dependent sufficient conditions for the design of a delayed output-feedback control are given by Lyapunov-Krasovskii method in terms of a linear matrix inequality (LMI). A controller, which guarantees H∞ synchronization of the master and slave structure using some free weighting matrices, is then developed. A numerical example has been given to show the effectiveness of the method

A User-Centric Approach to eCertificate for Electronic Identities (eIDs) Management in Mobile Environment

The use of electronic documents is constantly growing and the necessity to implement an ad-hoc eCertificate which manages access to private information is not only required but also necessary. This paper presents a protocol for the management of electronic identities (eIDs), meant as a substitute for the paper-based IDs, in a mobile environment with a user-centric approach. Mobile devices have been chosen because they provide mobility, personal use and high computational complexity. The inherent user-centricity also allows the user to personally manage the ID information and to display only what is required. The chosen path to develop the protocol is to migrate the existing eCert technologies implemented by the Learning Societies Laboratory in Southampton. By comparing this protocol with the analysis of the eID problem domain, a new solution has been derived which is compatible with both systems without loss of features.

A data-driven approach to disease control

As our world becomes increasingly interconnected, diseases can spread at a faster and faster rate. Recent years have seen large-scale influenza, cholera and ebola outbreaks and failing to react in a timely manner to outbreaks leads to a larger spread and longer persistence of the outbreak. Furthermore, diseases like malaria, polio and dengue fever have been eliminated in some parts of the world but continue to put a substantial burden on countries in which these diseases are still endemic. To reduce the disease burden and eventually move towards countrywide elimination of diseases such as malaria, understanding human mobility is crucial for both planning interventions as well as estimation of the prevalence of the disease. In this talk, I will discuss how various data sources can be used to estimate human movements, population distributions and disease prevalence as well as the relevance of this information for intervention planning. Particularly anonymised mobile phone data has been shown to be a valuable source of information for countries with unreliable population density and migration data and I will present several studies where mobile phone data has been used to derive these measures.

Social Responsibility, an Approach to the Executive Peruvian Perspective

In recent years the issue of social responsibility is becoming more important, which isreflected in the companies have incorporated it into their agenda of interests. In this sense,the article is intended to make a first approach to the level of implementation efforts, aswell as their prospects for the future. We interviewed a total of 144 people representingdifferent economic sectors. We conclude that the majority of executives do not have aclear understanding of the modern concept of RS nor of its benefits, it limits the concept tophilanthropy and actions are oriented to the community and environment.

An Approach to the Integration of Skills in English Teaching. 'Un acercamiento a la integración de habilidades en la enseñanza del inglés'.

Resumen de la revista

The rasch approach to 'objective measurement' in the presence of subjective evaluation from judges. 'Aproximación al modelo de 'medición objetiva' de rasch en presentación de la evaluación subjetiva por jueces'.

Resumen tomado de la publicación. Monográfico titulado: economía de la educación

Adaptive computer assisted assessment of free-text students answers : an approach to automatically generate students' conceptual models.

Las formas de evaluación basadas en el uso de tests no pueden identificar muchos errores conceptuales de los estudiantes. Esta investigación tiene como objetivo facilitar un nuevo procedimiento capaz de generar los modelos conceptuales de los estudiantes de forma automática a partir de respuestas en texto libre.. Este trabajo se organiza en tres apartados. En primer lugar, se procede a la revisión del estado de la cuestión. A continuación se describen el procedimiento para generar automáticamente los modelos conceptuales de los estudiantes y los sistemas que implementan dicho procedimiento. Por último se ofrecen: una explicación de los experimentos realizados y sus resultados, las conclusiones obtenidas y las líneas de trabajo futuro. Además se proporciona información para aplicar el procedimiento en otro idioma y/o área de conocimiento.. Se propone un procedimiento para generar automáticamente modelos conceptuales de cada estudiante y de una clase a partir de las respuestas facilitadas al sistema de evaluación automático y adaptativo. Estos sistemas son la evolución de los actuales de evaluación de respuestas en texto libre, que evalúan respuestas en texto libre automáticamente y de forma adaptada al modelo de cada estudiante..

Una aproximación documental para la creación e integración de juegos digitales en entornos virtuales de enseñanza. A documental approach to the creation and integration of digital videogames in virtual learning environments

Desde el campo de la informática educativa, varios autores exponen el posible efecto positivo de incorporar videojuegos y simulaciones con elementos de juego en los procesos educativos. Esta postura continúa siendo objeto de debate y sus detractores identifican, dos problemas fundamentales, por un lado el excesivo coste de estas iniciativas y, por otro, su carácter limitado que obliga a que formen parte de variados procesos educativos.. En este trabajo se estudia cómo abordar estos dos problemas desde un punto de vista tecnológico. Se propone una plataforma menor que e-adventure, un entorno de desarrollo para juegos educativos. Esta plataforma aborda el primer problema planteando, un modelo de proceso de desarrollo inspirado en la aproximación documental al desarrollo de software. El modelo de proceso incluye la propuesta de un lenguaje de marcado extendido, XML, específico del dominio de las aventuras gráficas educativas. Este lenguaje es sencillo de utilizar y facilita la creación de este tipo de juegos e incluye construcciones específicamente educativas que dan soporte a la evaluación de la actividad del alumno y a patrones de aprendizaje adaptativo. El segundo problema se aborda proponiendo la integración de dichos juegos con plataformas de tele-enseñanza, LMS, que se emplean tanto en la enseñanza a través de internet como en aproximaciones del aprendizaje electrónico, e-learning, combinadas con la enseñanza tradicional.. Se incluye la implementación de un prototipo de la plataforma propuesta y varios juegos educativos desarrollados con ella, en colaboración con investigadores e instructores de otros campos..