Genetic programming was used to evolve a direct search optimization algorithm, similar to that of the standard downhill simplex optimization method proposed by Nelder and Mead (1965). In the training process, several ten-dimensional quadratic functions with randomly displaced parameters and different randomly generated starting simplices were used. The genetically obtained optimization algorithm showed overall better performance than the original Nelder–Mead method on a standard set of test functions. We observed that many parts of the genetically produced algorithm were seldom or never executed, which allowed us to greatly simplify the algorithm by removing the redundant parts. The resulting algorithm turns out to be considerably simpler than the original Nelder–Mead method while still performing better than the original method.
COBISS.SI-ID: 11276628
Smartphones are currently the most pervasive wearable devices. One particular use of smartphone inertial sensors is motion tracking in various mobile systems and applications. The objective of this study is to validate smartphone gyroscopes for angular tracking in mobile biofeedback applications. The validation method includes measurements of angular motion performed concurrently by a smartphone gyroscope and a professional optical tracking system serving as the reference. The comparison of the measurement results shows that the inaccuracies of a calibrated smartphone gyroscope for various movements are between 0.42° and 1.15°. Based on the measurement results and the general requirements of biofeedback applications, smartphone gyroscopes are sufficiently accurate for angular motion tracking in mobile biofeedback applications.
COBISS.SI-ID: 11470164
An optoelectronic oscillator (OEO) with a regenerative electronic circuit that increases the selectivity of the oscillator’s loop is presented. The regenerative circuit works as a multiplier of the bandpass filter’s quality factor. This makes it possible to realize very narrow bandwidths and thus increase the side-mode suppression ratio of the OEO. Our measurements show an almost 20-dB increase in the suppression of the side modes at the expense of an increase in the phase noise by approximately 4 dB at a 1-kHz frequency offset.
COBISS.SI-ID: 11308628
This letter proposes a novel algorithm for reliable and accurate ground control point (GCP) estimation, which uses vector road network data as a reference. Roads are detected in satellite images, and road patches are used as a template, which is matched against the vector road data by using a nonlinear criterion based on the distance transform. The proposed approach is compared with the standard correlation-based template matching in terms of the reliability and accuracy of localization on a test set of five RapidEye images with 380 reference control points. The experiments demonstrate superior reliability with respect to the size of the search window and the variable image acquisition conditions. While the subpixel accuracy is achieved by the cross-correlation method over the search area up to 20% of the template size, the proposed method achieves comparable accuracy over a search area that is ten times larger than the template image
COBISS.SI-ID: 11473236
The paper presents a user study in which the sensitivity to cognitive load of visual, audio and tactile DRT is compared in a simulated driving environment. It also explores if the DRT method is least sensitive to cognitive load when the stimuli and secondary task are of the same modality. The participants’ primary task in the study was to drive safely, and as a second priority to answer to DRT stimuli and perform secondary tasks. The results indicate that all three versions of the DRT tested were sensitive to detecting the difference in cognitive load, and no interaction was observed between DRT modality and the stimuli modality used for presentation of the secondary tasks.
COBISS.SI-ID: 11508820