Jurij F. Tasic

Colour spaces: perceptual, historical and applicational background

In this paper, we present and overview of colour spaces used in electrical engineering and image processing. We stress the importance of the perceptual, historical and applicational background that led to a colour space. The colour spaces presented are: RGB, opponent-colour spaces, phenomenal colour spaces, CMY, CMYK, TV colour spaces (YUV and YIQ), PhotoYCC, CIE XYZ, Lab and Luv colour spaces.

Unsupervised quantification of whisking and head movement in freely moving rodents

The rodent whisker system has become the leading experimental paradigm for the study of active sensing. Thanks to more sophisticated behavioral paradigms, progressively better neurophysiological methods, and improved video hardware/software, there is now the prospect of defining the precise connection between the sensory apparatus and brain activity in awake, exploring animals. Achieving this ambitious goal requires quantitative, objective characterization of head and whisker kinematics. This study presents the methodology and potential uses of a new automated motion analysis routine. The program provides full quantification of head orientation and translation, as well as the angle, frequency, amplitude, and bilateral symmetry of whisking. The system operates without any need for manual tracing by the user. Quantitative comparison to whisker detection by expert humans indicates that the programs correct detection rate is at >95% even on animals with all whiskers intact. Particular attention has been paid to obtaining reliable performance under nonoptimal lighting or video conditions and at frame rates as low as 100. Variation of the zoom across time is compensated for without user intervention. The program adapts automatically to the size and shape of different species. The outcome of our testing indicates that the program can be a valuable tool in quantifying rodent sensorimotor behavior.

Predicting and Detecting the Relevant Contextual Information in a Movie-Recommender System

Context-aware recommender system (CARS) is a highly researched and implemented way of providing a personalized service that helps users to find their desired content. One of the remaining issues is how to decide which contextual information to acquire and how to incorporate it into CARS. While the relevant contextual information will improve the recommendations, the irrelevant contextual information could have a negative impact on the recommendation accuracy. By testing the independence between the contextual variable on the users’ ratings for items, we can detect its relevanceandimpactonthefeedbackfortheitemconsumedinthatspecificcontext.Inthisarticle,we propose several new theoretical concepts that should help deciding which information to use, as well as a methodology for detecting which contextual information contributes to explaining the variance in the ratings, based on statistical testing. The experiment was conducted on the real movie dataset that contains 12 different pieces of contextual information. We used two statistical tests with power analysis for the detection, and three contextualized matrix-factorization algorithms with slightly different reasoning for the prediction of ratings. The results showed a significant difference in the prediction of ratings in the context that was detected as relevant by our method, and the one that was detected as irrelevant, pointing to the importance of the power analysis and the benefits of the proposed method in the case of a small dataset.

Information systems security and human behaviour

Until recently, most of the effort for providing security in information systems has been focused on technology. However, it turned out during the last years that human factors have played a central role. Therefore, to ensure appropriate security in contemporary information systems, it is necessary to address not only technology-related issues, but also human behaviour and organisation-related issues that are usually embodied in security policies. This paper presents a template model, which is intended to support risk management for information systems, and which is concentrated on human factors. The model is based on business dynamics that provide the means for qualitative and quantitative treatment of the above-mentioned issues.

Frequency Characteristics Measurement of Overhead High-Voltage Power-Line in Low Radio-Frequency Range

This paper presents measurement results of frequency characteristics of the high-voltage power line in low radio-frequency range: amplitude and phase characteristic, group delay, and input impedance. Measurement results for the 400-kV overhead power-line under operation are presented together with the developed measurement methodology. The methodology provides a method to measure amplitude and phase characteristics, group delay and the return loss of the HV power line for a geographically distributed system utilizing an optical link as a return path. The measurement results confirm very low attenuation with a linear phase, but with oscillations present in all characteristics caused by reflection of the signal on the power line. The complete knowledge of frequency characteristics of the HV power line and noise description is crucial for the design of digital power-line carrier (PLC) systems.

Personal Content Recommender Based on a Hierarchical User Model for the Selection of TV Programmes

In this paper we present our approach to user modeling for a personalized selection of multimedia content tested on a corpus of TV programmes. The idea of this approach is to classify content (TV programmes) based on the calculation of similarities between the description of content and the user model for each description attribute. Calculated similarities are then combined into a classification decision using the Support Vector Machines. The basis for the calculation of similarities is a hierarchical structure of the user model, overlaid upon a taxonomy of TV programme genres. Preliminary results show that it works well with a varying quality of content descriptions including incomplete genre classification and arbitrary number of description attributes. The evaluation of the system performance was based on content described using the TV-Anytime standard, but the approach can be adapted for search of other types of content with multi-attribute descriptions.

Share it! - content transfer in home-to-home networks

This paper presents a possible solution for the introduction of a complementary distribution chain into the broadcast environment. In the described scenario, personal video recorders with local storage are networked into an ad-hoc home-to-home network based on an emerging peer-to-peer protocol that enables broadcast as well as home-produced content sharing. The paper presents the current system architecture as conceived within a consortium working on the Share it! project.

Computation of high-frequency and time characteristics of corona noise on HV power line

This work presents an algorithm for the computation of frequency and time characteristics of the corona noise in power-line carrier communications. In the frequency domain, the corona noise is represented with a power spectral density and with a Gaussian noise voltage with variable root mean square value in the time domain. Simulations results are compared with measurements on an actual 400-kV power line.

Detection of the electrocardiogram fiducial points in the phase space using the euclidian distance measure

The paper proposes a phase-space based algorithm applying the Euclidian distance measure enabling detection of heartbeats and characteristic (fiducial) points from a single-lead electrocardiogram (ECG) signal. It extends the QRS detection in the phase space by detecting the P and T fiducial points. The algorithm is derived by reconstructing the ECG signals in a two-dimensional (2D) phase space according to the delay method and utilizes geometrical properties of the reconstructed phase portrait of the signal in the phase space for the heartbeat and fiducial-point detection. It uses adaptive thresholding and the Euclidian distance measure between the signal points in the phase portrait as an alternative to the phase-portrait area calculation (Lee et al., 2002). It was verified with the QT Database (2011) and its performance was assessed using sensitivity (Se) and the positive predictive value (PPV). Results for the proposed algorithm are 99.06%, 99.75% and 99.66% for Se and 94.87%, 99.75% and 99.66% for PPV for the P points, heartbeats and T points, respectively.

Comparative analysis of methods for broadcase elimination

Abstract A comparative analysis is completed on the methods for broadcast elimination. Some authors use approaches to determine the best affine schedule. Another approach is by reindexing multistep algorithms at the algorithm representation level, decomposing the algorithm and pipelining and routing dataflow for each step. Transformations at the algorithm model level and some heuristic approaches are also considered.