Matej Zajc

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.

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.

High-frequency characteristics of high-voltage power line

This paper presents a major high-frequency characteristic of high-voltage overhead power line: amplitude characteristics, group delay and noise characteristics. Since measurements of high-frequency power-line characteristics are rare due to permission of power utilities for access to power lines, computer simulations have a crucial role in design of communication systems via power lines. Simulated high-frequency and noise characteristics of 400 kV power line are presented and compared with measurements on actual power line.

High voltage power line constraints for high speed communications

Paper presents technical limitations and constraints of high-voltage power-lines for high-speed digital PLC communications. Signal reflection and noise characteristics are recognized as major technical limitations for digital PLC system development. Results from a computer model and measurements are presented. Proposed solutions are at the end.

Corona noise characteristics in high voltage PLC channel

The paper presents the algorithm for estimation of frequency and time characteristics of the corona noise in high voltage power-line carrier (PLC) communications. In the frequency domain corona noise is represented with power spectral density and with Gaussian noise voltage with variable root mean square (RMS) value in time domain. The analytic method for estimation of the corona noise appearing at the line terminals in frequency and time domain is given. Simulations results are compared with the measurements on actual 400 kV power line.

Power line noise model appropriate for investigation if channel coding methods

This paper presents an experimental and theoretical research of power line noise performed on overhead power line. High voltage (HV) power line, as a communication media, is a source by itself of different noises characterizing an important signature of this communication media. Investigation of appropriate channel coding techniques by computer simulations requires transfer characteristics of channel and statistical model of noise. In this paper, the computer model of power line noise is presented. A simulation of the noise is carried out in Matlab.

An interactive tangible user interface application for learning addition concepts

Introduction Interactive multimedia technologies are present in our day-to-day lives. Children accept them and use them intuitively at home. At school, multimedia technology penetration in classrooms is, however, often limited to computer rooms and interactive whiteboards with projectors. This paper evaluates the design and introduction of a tabletop system using a tangible user interface (TUI) in the classroom environment. Tangible systems possess advantages for children’s interaction in the learning process (O’Malley & Fraser, 2004). TUIs enable interaction with the computer, providing the ability to manipulate the digital environment by controlling objects in the physical environment (Ishii, 2008).

Power-line high-frequency characteristics: analytical formulation

The design of digital communication systems via overhead high voltage power-lines, namely digital power line carrier (dPLC), requires knowledge of the power-line high frequency characteristics. The paper derives an analytical formulation for high-voltage power-line high-frequency characteristics: amplitude and phase characteristics and group delay. Analytical expressions are derived for a power-line with three conductors in horizontal disposition and middle phase to ground coupling. These characteristics can be obtained numerically. On the other hand, the analytical description provides the nature of the media.

Development of interactive television t-learning course

Paper presents some of the latest advances in the use of iDTV for educational purposes offering learner to actively participate in the course. We explore the potentials to expand the power of iDTV by delivering interactive learning into the home and present open issues and development experience respectively. Paper presents research results of IST project ELU - enhanced learning unilimited.