André Dias

UiT The Arctic University of Norway · Department of Computer Science

Elderly people obtain significant health benefits from physical activity (PA), but the role of activity patterns has scarcely been researched. The present study aims to describe the patterns of PA among different intensities of activity in elderly people. We assess how patterns differ between more and less active groups ('rare', 'average', and 'fre...

Background: Chronic obstructive pulmonary disease (COPD) is a progressive disease affecting the airways, which constitutes a major cause of chronic morbidity and a significant economic and social burden throughout the world. Despite the fact that in COPD patients exacerbations are common acute events causing significant and often fatal worsening o...

Periodic limb movements are short movements of the legs that can lead to low sleep quality in the general population. Currently, the gold standard to measure periodic limb movements for diagnostic purposes is polysomnography. This is an expensive technique that requires specially fitted laboratories and specialized personnel. In this paper we explo...

We measured lower limb activity by means two, above each ankle vertically aligned GT3X+ accelerometers in 4 healthy adults during a single night. Triaxial raw data vector magnitude units (VMU) were recorded at 100 Hz, in order to compare two different modes of operation (i.e. low power mode (LPM)on vs. off).

Due to the large variety of methods for collecting and analyzing accelerometer data to assess physical activity, it is difficult to compare results from different studies. Therefore, this work aims to provide recommendations for the collection and processing of such data in older people, focusing on the assessment of wearing time and intensity leve...

Background: Accelerometry is increasingly used to assess physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD). It is not known how the relationship of PA to clinical results depends on the position of the PA sensor. Methods: We assessed the effect of monitor position by measuring lower extremity (ankle), upper ext...

Physical Activity (PA) plays an important role in the health and quality of life of cystic fibrosis (CF) patients, but little is known about their PA in daily living. With the use of accelerometers it is now possible to monitor activity profiles in detail. The goals of this study are to assess feasibility and acceptance of a longer-term use of acce...

A temporal scale-space is a vector space spanned by time and a scale parameter, and by constructing the scale-space correctly a causal structure can be imposed on the scale-space. This enables early warning of significant changes in sensor data at an early time, and on any scale. We describe a feasibility study on how to use these ideas for live su...

A health forum is a kind of social network where users share information for specific topics they create. The purpose of this study was the identification of the key actors and the user communities in such a network. We used the publicly available data from a diabetes forum to create the corresponding network and explore several algorithms for the...

The objective of the KORA-Age research consortium is to assess the determinants and consequences of multimorbidity in the elderly and to look into reasons for successful aging in the general public. In the KORA-Age cohort study 9,197 persons were included who where born in the year 1943 or before and participants of previous KORA cohort studies con...

Spatiotemporal gait parameters are very important for the detection of gait impairments and associated conditions. Current methods to measure such parameters, e.g. electronic walkways or force plates, are costly and can only be used in a laboratory. The new generation of raw data accelerometers might be a cheap and flexible alternative. We conducte...

For the assessment of physical activity, motion sensors have become increasingly important. To assure a high accuracy of the generated sensor data, the measurement error of these devices needs to be determined. Sensor variability has been assessed with various types of mechanical shakers. We conducted a small feasibility study to explore if a progr...

Long term wearing of motion and heart rate sensors are essential aspects for longitudinal studies on physical activity measurement studies. We conducted a qualitative study with seven subjects in a total of 13 test sessions to identify usability and handling problems associated with Stayhealth RT3, Actigraph GT1M and Polar RS800 sensors. We found t...

Genetic Programming involves the evolution of computer programs, which are usually represented by trees composed by functions and terminals. In order to assign fitness, one must evaluate the programs, which is the most time demanding step of GP. In nowadays standard approaches, the evaluation involves an interpretation step. To avoid this step, whi...

This paper is about the colouring of greyscale images. More specifically, we address the problem of learning to colour greyscale images from a set of examples of true colour ones. We employ Genetic Programming to evolve computer programs that take as input the Lightness channel of the training images and output the Hue channel. The best programs ev...

This paper is about the colouring of greyscale images. More specifically, we address the problem of learning to colour greyscale images from a set of examples of true colour ones. We employ Genetic Programming to evolve computer programs that take as input the Lightness channel of the training images and output the Hue channel. The best programs ev...

In this paper we propose the extension of current genome compiler systems through the inclusion of two techniques, and study the effects on the performance of the system. The goal is to reduce the number of operations necessary to evaluate the individuals, hence reducing the computational weight of the evaluation step.