Enhanced Machine Learning Techniques for Early HARQ Feedback Prediction in 5G

We investigate Early Hybrid Automatic Repeat reQuest (E-HARQ) feedback schemes enhanced by machine learning techniques as a path towards ultra-reliable and low-latency communication (URLLC). To this end, we propose machine learning methods to predict the outcome of the decoding process ahead of the end of the transmission. We discuss different input features and classification algorithms ranging from traditional methods to newly developed supervised autoencoders. These methods are evaluated based on their prospects of complying with the URLLC requirements of effective block error rates below $10^{-5}$ at small latency overheads. We provide realistic performance estimates in a system model incorporating scheduling effects to demonstrate the feasibility of E-HARQ across different signal-to-noise ratios, subcode lengths, channel conditions and system loads, and show the benefit over regular HARQ and existing E-HARQ schemes without machine learning.Comment: 14 pages, 15 figures; accepted versio

A rate control algorithm for HEVC with hierarchical GOP structures

In this paper a buffer-constrained rate control (RC) algorithm for High Efficiency Video Coding (HEVC) with hierarchical group of pictures structures is proposed. Specifically, a quantization parameter (QP) cascading approach, which the QP value is increased from one temporal layer to the next, is employed to achieve high coding efficiency while maintaining the buffer fullness at secure levels. When compared to the current state-of-the-art RC algorithm, the experimental results show that our proposal achieves a slightly better rate-distortion performance and a remarkably better buffer control with an acceptable increase in computational complexity

Theoretical Models for Video on Demand Services on Peer-to-Peer Networks

Peer-to-peer networks (P2Ps) are becoming more and more popular in video content delivery services, such as TV broadcast and Video on Demand (VoD), thanks to their scalability feature. Such characteristic allows for higher numbers of simultaneous users at a given server load and bandwidth with respect to alternative solutions. However, great efforts are still required to study and design reliable and QoS-guaranteed solutions. In this paper, within the scenario of P2P-based VoD services, we study the phenomenon of peer churns and propose four models of the peer behaviour to evaluate its impact on the system performance, which are based on the Gilbert-Elliot chain, the fluidic representation of the user behavior, and a queuing analysis of the system. The models are compared by computing the resources the system has to add on top of the P2P network to satisfy all the download requests. Simulations show important relationships between playback buffer length, peer request rate, peer average lifetime, and server upload rate

Social Marketing. Ein hilfreicher Weg für die Kirche?

Angesichts sich häufender Austritte von Mitgliedern der beiden großen christlichen Kirchen stellt sich - zwnindest für denjenigen, der nicht unbedingt der Meinung ist, es handle sich hierbei wn ein vielleicht sogar notwendiges "Gesundschrwnpfen" -die Frage, ob Werbung ein geeignetes Mittel zur Verlangsamung, zum Stoppen oder sogar zum Umkehren dieses Prozesses sein könnte und wenn ja, wie eine Werbung für Kirche aussehen müßte bzw. wie sie nicht aussehen dürfte. (...)  EnglishSUMMARY: Social marketing. A useful way for the Church?The question, whether the Church should push forward advertising efforts or not, is old-fashioned. The Church has to advertise, if it wants to resolve its proble1ns within society and the problems of society with the Church. Certainly, these problems are far too complex to be resolved by the use of advertisement only. The necessary changes of values and norms are not possible with fancy talks and pious words, but only with far-reaching strateg1es and similar fundamental steps

Monedas del litoral marítimo. Un tesoro Emiral compuesto por monedas de plata procedente de un asentamiento portuario del Cerro da Vila (Vilamoura, Algarve, Portugal)

Cerro da Vila was founded as a Roman production and harbour settlement (“agglomeracion secundaire”) at the end of the Republican Age. It developed into a small seaside settlement (“aldeia do mar”), largely based on the exploitation of maritime resources, although it is unlikely that this exploitation exceededsubsistence level. The abandonment of the settlement probably resulted from violent attack and destruction at the end of the 11th / beginning of the 12th century AD. A hoard of 239 silver coins and fragments were discovered at the bottom of an Islamic storage pit dug into the ground in an area of the former Roman site, where several remains of buildings and layers confirm settlement activity in the Visigothic and Islamic period. The latest coin is dated 270/883-4, but the hoard might have been buried some years later. It is likely that the hoard represents a small random sample of the coin circulation in Gharb al-Andalus. Most of the coins are fragmented. As it is typical for that period, a number are slotted and slashed coins; some of them are plugged with tiny pieces of silver. With the exception of two Carolingian deniers all the identifiable coins are from Cordoba, proving a tight control of the circulation of coins in al-Andalus. The hoard belongs to a horizon of similar hoards from southern and south-western al-Andalus which were buried in the 260s/870s and 270s/880s. Their composition is discussed in the article. They all belong to the period of the uprising of the muwallad landowner ʿUmar ibn Ḥafṣūn between 267/880-1 and 303/915- 6, against the Emirate of Cordoba.El Cerro da Vila se fundó como asentamiento romano de producción y puerto (“aglomeración secundaria”) al final de la época republicana. Con el tiempo, se convirtió en un pequeño asentamiento costero (“aldeia do mar”), con una actividad basada en gran medida en la explotación de los recursos marítimos, aunque es poco probable que su explotación excediera el nivel de subsistencia. El abandono del asentamiento fue probablemente resultado de un ataque violento y destrucción a finales del siglo XI / comienzos del siglo XII. Un tesoro de 239 monedas de plata y fragmentos fue descubierto en el fondo de un silo de almacenamiento de época islámica, excavado en el suelo en una zona del antiguo emplazamiento romano, donde los restos de edificios y la estratigrafía confirman la actividad de asentamiento en los periodos visigodo e islámico. la cronología de la última moneda encontrada data de 270/883-4, pero el tesoro podría haber sido enterrado algunos años después. Es probable que el tesoro represente una pequeña muestra aleatoria de la circulación de monedas en Garb al-Andalus. la mayoría de las monedas están fragmentadas. Como es típico de este período, un gran número de las monedas están cortadas y ranuradas; y algunas de éstas están conectadas con pequeñas piezas de plata. Con la excepción de dos denarios carolingios, todas las monedas identificables proceden de Córdoba, lo que demuestra un estricto control de la circulación de monedas en al-Andalus. El tesoro pertenece a una zona del sur y el sudoeste de al-Andalus en la que se han encontrado tesoros similares que fueron enterrados en los años 260, 270, 870 y 880. Este artículo discute la composición de las monedas. Estas pertenecen al período de la sublevación del terrateniente muwallad ‘Umar Ibn Ḥafṣūn entre los años 267/880-1 y 303/915-6, contra el Emirato de Córdoba

Layer-Aware Forward Error Correction for Mobile Broadcast of Layered Media

The bitstream structure of layered media formats such as scalable video coding (SVC) or multiview video coding (MVC) opens up new opportunities for their distribution in Mobile TV services. Features like graceful degradation or the support of the 3-D experience in a backwards-compatible way are enabled. The reason is that parts of the media stream are more important than others with each part itself providing a useful media representation. Typically, the decoding of some parts of the bitstream is only possible, if the corresponding more important parts are correctly received. Hence, unequal error protection (UEP) can be applied protecting important parts of the bitstream more strongly than others. Mobile broadcast systems typically apply forward error correction (FEC) on upper layers to cope with transmission errors, which the physical layer FEC cannot correct. Today's FEC solutions are optimized to transmit single layer video. The exploitation of the dependencies in layered media codecs for UEP using FEC is the subject of this paper. The presented scheme, which is called layer-aware FEC (LA-FEC), incorporates the dependencies of the layered video codec into the FEC code construction. A combinatorial analysis is derived to show the potential theoretical gain in terms of FEC decoding probability and video quality. Furthermore, the implementation of LA-FEC as an extension of the Raptor FEC and the related signaling are described. The performance of layer-aware Raptor code with SVC is shown by experimental results in a DVB-H environment showing significant improvements achieved by LA-FEC. © 2011 IEEE.Hellge, C.; Gómez Barquero, D.; Schierl, T.; Wiegand, T. (2011). Layer-Aware Forward Error Correction for Mobile Broadcast of Layered Media. IEEE Transactions on Multimedia. 13(3):551-562. doi:10.1109/TMM.2011.2129499S55156213

Low-latency Cloud-based Volumetric Video Streaming Using Head Motion Prediction

Volumetric video is an emerging key technology for immersive representation of 3D spaces and objects. Rendering volumetric video requires lots of computational power which is challenging especially for mobile devices. To mitigate this, we developed a streaming system that renders a 2D view from the volumetric video at a cloud server and streams a 2D video stream to the client. However, such network-based processing increases the motion-to-photon (M2P) latency due to the additional network and processing delays. In order to compensate the added latency, prediction of the future user pose is necessary. We developed a head motion prediction model and investigated its potential to reduce the M2P latency for different look-ahead times. Our results show that the presented model reduces the rendering errors caused by the M2P latency compared to a baseline system in which no prediction is performed.Comment: 7 pages, 4 figure

Video processing for panoramic streaming using HEVC and its scalable extensions

Panoramic streaming is a particular way of video streaming where an arbitrary Region-of-Interest (RoI) is transmitted from a high-spatial resolution video, i.e. a video covering a very “wide-angle” (much larger than the human field-of-view – e.g. 360°). Some transport schemes for panoramic video delivery have been proposed and demonstrated within the past decade, which allow users to navigate interactively within the high-resolution videos. With the recent advances of head mounted displays, consumers may soon have immersive and sufficiently convenient end devices at reach, which could lead to an increasing demand for panoramic video experiences. The solution proposed within this paper is built upon tile-based panoramic streaming, where users receive a set of tiles that match their RoI, and consists in a low-complexity compressed domain video processing technique for using H.265/HEVC and its scalable extensions (H.265/SHVC and H.265/MV-HEVC). The proposed technique generates a single video bitstream out of the selected tiles so that a single hardware decoder can be used. It overcomes the scalability issue of previous solutions not using tiles and the battery consumption issue inherent of tile-based panorama streaming, where multiple parallel software decoders are used. In addition, the described technique is capable of reducing peak streaming bitrate during changes of the RoI, which is crucial for allowing a truly immersive and low latency video experience. Besides, it makes it possible to use Open GOP structures without incurring any playback interruption at switching events, which provides a better compression efficiency compared to closed GOP structures