DAB+ Network Implementation in the Czech Republic and Impact of the Audio Coding on Subjective Perception of Sound Quality

Digital Audio Broadcasting (DAB+) is becoming a reality in the Czech Republic. The first nationwide DAB+ network, based on the regular broadcasting, is being completed. This paper presents the principles that were used to achieve a quick and efficient penetration of the DAB+ signal in the Czech population and the highways. Attention is focused on practical experience with the use of High-Efficiency Advanced Audio Coding (HE-AAC) emphasizing maximum efficiency of the multiplex. This is done with respect to the subjective perception of sound quality by the audience. Final audio processing and appropriate signal pre-processing are considered. The paper also focuses on how to use Forward Error Correction (FEC) coding to increase the reach of transmitters and the reasons for employing the specific transmitter network configuration, including indoor reception. The results of this complex method are demonstrated on the network rollout in particular periods, while the key assumptions were verified. The entire development process can be monitored on the maps of coverage

Composite piles: A review

Traditional piling in the form of steel, concrete or timber is susceptible to hazards within harsh marine environments. The deterioration of wood, corrosion of steel and degradation of reinforced/prestressed concrete piles in deep foundations has led researchers to experiment with methods to overcome these problems. Composite material piles, such as fibre-reinforced polymers (FRP) and structurally reinforced plastics (SRP), are a unique solution to the problems faced by traditional piling in marine environments. Their resistance to corrosion and long service life make them an economical and environmentally viable solution to traditional piling. Although a few manufacturers have begun to adopt some form of composite piling for fender applications, barriers remain that prevent their widespread use as load bearing piles. These barriers include the lack of specific driving and installation guidelines, limited full-scale geotechnical design data, long-term durability studies and in-depth environmental impact studies. To facilitate research in the aforementioned areas, this review paper details the historical use of composite piles, the structural and geotechnical design of several types of load bearing composite piles, the durability of piles, and, lastly, the construction and manufacturing processes involved. The findings show that there is a general consensus amongst researchers that fibre-reinforced piles (FRP) are structurally and geotechnically suitable for a range of load bearing applications, and that SRP piles, with adequate reinforcement, can potentially be used in deep foundations. More full-scale field research is still needed to develop sufficient driving guidelines, and durability tests emulating saline marine conditions should be carried out to assess the effectiveness of epoxies, and, lastly, reinforcing arrangements should be tested to prevent lateral deflection