Subjective Quality Assessment of the Impact of Buffer Size in Fine-Grain Parallel Video Encoding

Fine-Grain parallelism is essential for real-time video encoding performance. This usually implies setting a fixed buffer size for each encoded block. The choice of this parameter is critical for both performance and hardware cost. In this paper we analyze the impact of buffer size on image subjective quality, and its relation with other encoding parameters. We explore the consequences on visual quality, when minimizing buffer size to the point of causing the discard of quantized coefficients for highest frequencies. Finally, we propose some guidelines for the choice of buffer size, that has proven to be heavily dependent, in addition to other parameters, on the type of sequence being encoded. These guidelines are useful for the design of efficient realtime encoders, both hardware and software

Simulation and Measurement of the Transmission Distortions of the Digital Television DVB-T/H (Part 1: Modulator for Digital Terrestrial Television)

The paper deals with the first part of results of the Czech Science Foundation research project that was aimed into the simulation and measurement of the transmission distortions of the digital terrestrial television according to DVB-T/H standards. In this part the modulator performance characteristics and its simulation and laboratory measurements are presented with focus on typical DVB-T/H broadcasting scenario – large SFN network for fixed reception. The paper deals with the COFDM modulator imperfections and I/Q errors influence on the DVB-T/H signals and the related I/Q constellation analysis. Impact of the modulator imperfections on Modulation Error Rate from I/Q constellation and Bit Error Rates before and after Viterbi decoding in DVB-T/H signal decoding are evaluated and discussed

Simulation and Measurement of the Transmission Distortions of the Digital Television DVB-T/H Part 3: Transmission in Fading Channels

The paper deals with the third (and last) part of results of the Czech Science Foundation research project that was aimed into the simulation and measurement of the transmission distortions of the digital terrestrial television according to DVB-T/H standards. In this part the transmission of the digital television according to DVB-T/H standard over the fading channels and their models and profiles for fixed, portable and mobile reception is analyzed. Impact of the fading channels and their models on Modulation Error Rate from I/Q constellations and Bit Error Rates before and after Viterbi decoding in DVB-T/H signal decoding is presented

Bio hält das Wasser rein! Eine ökonomische Bewertung

Die Biologisch Landwirtschaft leistet aus folgenden Gründen einen wichtigen Beitrag zum Grundund Trinkwasserschutz: Die Beeinträchtigung durch chemisch-synthetische Pflanzenschutzmittel ist ausgeschlossen. Aufgrund des angestrebten geschlossenen Betriebskreislaufes und rechtlicher Vorgaben ist der Eintrag von Nitrat in das Grund- und Trinkwasser drastisch reduziert. Ökonomische Berechnungen zeigen, dass die Biologische Landwirtschaft zur Verringerung von Kosten, die gegenwärtig die Allgemeinheit tragen muss, beiträgt. Biologischer Landbau bedeutet damit vorsorgenden Grundwasserschutz anstelle nachsorgender Maßnahmen

DVB-T Digital Terrestrial Television Transmission over Fading Channels

The paper deals with the transmission of the digital television signal according to the DVB-T standard in SFN network over fading channels for the fixed reception. The laboratory transmission system for the real broadcasting based on R&S RF test and measuring equipments is presented including the transmission parameters setup. The results of broadcasting over Gausian, Ricean and Rayleigh channels and results of the echo impairments are presented and discussed with the theory and simulation results. The BER before and after Viterbi decoding and according to MER equal to S/N ratio in the channel from the constellation diagram were compared in all transmission experiments. Additional picture quality evaluation is presented using DVQL-W metric that monitors blockiness structures in MPEG-2 compressed pictures and gives notice of known \"cliff-off\" effect

Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands – Advanced Co-Existence Scenarios

The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co-existences between still used and upcoming mobile networks (from GSM to LTE) and digital terrestrial television broadcasting (DVB) systems. For all of these measurements and their evaluation universal measurement testbed has been proposed and used. Results presented in this paper are a significant part of our activities in work package WP5 in the ENIAC JU project “Agile RF Transceivers and Front-Ends for Future Smart Multi-Standard Communications Applications (ARTEMOS)”

Testing QoE in Different 3D HDTV Technologies

The three dimensional (3D) display technology has started flooding the consumer television market. There is a number of different systems available with different marketing strategies and different advertised advantages. The main goal of the experiment described in this paper is to compare the systems in terms of achievable Quality of Experience (QoE) in different situations. The display systems considered are the liquid crystal display using polarized light and passive lightweight glasses for the separation of the left- and right-eye images, a plasma display with time multiplexed images and active shutter glasses and a projection system with time multiplexed images and active shutter glasses. As no standardized test methodology has been defined for testing of stereoscopic systems, we develop our own approach to testing different aspects of QoE on different systems without reference using semantic differential scales. We present an analysis of scores with respect to different phenomena under study and define which of the tested aspects can really express a difference in the performance of the considered display technologies

Konsequenzen einer großflächigen Umstellung auf ökologischen Landbau

Die aktuellen Schwierigkeiten im Agrarsektor haben ein bisher nicht dagewesenes Interesse an einer verstärkten Förderung des ökologischen Landbaus durch gezielte agrarpolitische Maßnahmen geweckt. Es werden Zielvorstellungen von bis zu 20% biologisch wirtschaftender Betriebe geäußert. Eine deutliche Zunahme dieser Betriebe ist aufgrund der weitgehend anerkannten und vielfach nachgewiesenen ökologischen Vorzüglichkeit der biologischen Landwirtschaft wünschenswert. Gleichzeitig stellt sich aber auch die Frage nach den ökonomischen und sozialen Konsequenzen einer weitgehenden Umstellung auf ökologischen Landbau. In einer Reihe von Studien wurde versucht, die Wirkungen einer flächendeckenden Umstellung ganzer Länder (Olson et al., 19821), Langley et al., 1983, für die USA; Bechmann et al., 1992, Zerger & Bossel, 1994, Seemüller, 2000, für Deutschland; Lampkin, 1994, für Großbritannien; Alroe & Kristensen, 2001, für Dänemark) oder Regionen (Rist et al., 1989, für den Kanton Zug; Braun, 1995, für Baden-Württemberg; Pommer & Rintelen, 1997, für Bayern) bzw. einer teilweisen Umstellung (Lampkin, 1994: 10 % ökologischer Landbau in Großbritannien; Wynen, 1998: 10 bis 80 %in Dänemark; Zander et al., 1999: in Brandenburg) abzuschätzen. Die Ergebnisse der zitierten Untersuchungen sollen hier vergleichend dargestellt und daraus Handlungsbedarf hinsichtlich einer großflächigen Umstellung abgeleitet werden