Brecht Vermeulen

Worldwide energy needs for ICT: The rise of power-aware networking

As Information and Communication Technology (ICT) is becoming more and more wide-spread and pervasive in our daily life, it is important to get a realistic overview of the worldwide impact of ICT on the environment in general and on energy and electricity needs in particular. This paper reports on a detailed study to estimate this impact today and to predict how this will evolve in the future. From this survey, important conclusions for the future of ICT industry and the Internet will be drawn, and challenges and research directives will be deduced.

Assessing Quality of Experience of IPTV and Video on Demand Services in Real-Life Environments

The ever growing bandwidth in access networks, in combination with IPTV and video on demand (VoD) offerings, opens up unlimited possibilities to the users. The operators can no longer compete solely on the number of channels or content and increasingly make high definition channels and quality of experience (QoE) a service differentiator. Currently, the most reliable way of assessing and measuring QoE is conducting subjective experiments, where human observers evaluate a series of short video sequences, using one of the international standardized subjective quality assessment methodologies. Unfortunately, since these subjective experiments need to be conducted in controlled environments and pose limitations on the sequences and overall experiment duration they cannot be used for real-life QoE assessment of IPTV and VoD services. In this article, we propose a novel subjective quality assessment methodology based on full-length movies. Our methodology enables audiovisual quality assessment in the same environments and under the same conditions users typically watch television. Using our new methodology we conducted subjective experiments and compared the outcome with the results from a subjective test conducted using a standardized method. Our findings indicate significant differences in terms of impairment visibility and tolerance and highlight the importance of real-life QoE assessment.

Constructing a No-Reference H.264/AVC Bitstream-Based Video Quality Metric Using Genetic Programming-Based Symbolic Regression

In order to ensure optimal quality of experience toward end users during video streaming, automatic video quality assessment becomes an important field-of-interest to video service providers. Objective video quality metrics try to estimate perceived quality with high accuracy and in an automated manner. In traditional approaches, these metrics model the complex properties of the human visual system. More recently, however, it has been shown that machine learning approaches can also yield competitive results. In this paper, we present a novel no-reference bitstream-based objective video quality metric that is constructed by genetic programming-based symbolic regression. A key benefit of this approach is that it calculates reliable white-box models that allow us to determine the importance of the parameters. Additionally, these models can provide human insight into the underlying principles of subjective video quality assessment. Numerical results show that perceived quality can be modeled with high accuracy using only parameters extracted from the received video bitstream.

No-Reference Bitstream-Based Visual Quality Impairment Detection for High Definition H.264/AVC Encoded Video Sequences

Ensuring and maintaining adequate Quality of Experience towards end-users are key objectives for video service providers, not only for increasing customer satisfaction but also as service differentiator. However, in the case of High Definition video streaming over IP-based networks, network impairments such as packet loss can severely degrade the perceived visual quality. Several standard organizations have established a minimum set of performance objectives which should be achieved for obtaining satisfactory quality. Therefore, video service providers should continuously monitor the network and the quality of the received video streams in order to detect visual degradations. Objective video quality metrics enable automatic measurement of perceived quality. Unfortunately, the most reliable metrics require access to both the original and the received video streams which makes them inappropriate for real-time monitoring. In this article, we present a novel no-reference bitstream-based visual quality impairment detector which enables real-time detection of visual degradations caused by network impairments. By only incorporating information extracted from the encoded bitstream, network impairments are classified as visible or invisible to the end-user. Our results show that impairment visibility can be classified with a high accuracy which enables real-time validation of the existing performance objectives.

Federating Wired and Wireless Test Facilities through Emulab and OMF: The iLab.t Use Case

The IBBT iLab.t technology centre provides computing hardware, software tools and measurement equipment to support researchers and developers in building their ICT solutions, and in measuring the performance of these solutions. Among other things, the iLab.t hosts several generic Emulab-based wired test environments called the Virtual Walls, and two wireless test environments which are grouped under the name w-iLab.t. Until very recently, these wired and wireless test facilities each had their own history: they were deployed and maintained by a different group of people, were operated using different tools, and each had their own community of experimenters. This paper provides insight on the origin and evolution of the Virtual Wall and w-iLab.t facilities. It explains how these facilities were federated, by using the best parts of both the OMF and Emulab frameworks. It discusses the benefits of our local federation as well as our future federation plans.

ViQID: A No-Reference bit stream-based visual quality impairment detector

In order to ensure adequate quality towards the end users at all time, video service providers are getting more interested in monitoring their video streams. Objective video quality metrics provide a means of measuring (audio)visual quality in an automated manner. Unfortunately, most of the current existing metrics cannot be used for real-time monitoring due to their dependencies on the original video sequence. In this paper we present a new objective video quality metric which classifies packet loss as visible or invisible based on information extracted solely from the captured encoded H.264/AVC video bit stream. Our results show that the visibility of packet loss can be predicted with a high accuracy, without the need for deep packet inspection. This enables service providers to monitor quality in real-time.

Power efficiency of thin clients

Worldwide, awareness for energy consumption is rising because of global energy production limits as well as because of environmental concerns. As the energy fraction currently consumed by ICT-related equipment is substantial (about 8 per cent of electricity consumption worldwide in the use phase) and the growth rate in this particular sector is spectacular, in the ICT sector, adequate solutions are needed to allow sustainable growth. In this paper we aim at reducing power consumption of desktop applications by applying a thin client approach and we analyse the conditions necessary. To this end, estimates on power consumptions in typical desktop scenarios and analogous thin client settings are made and analysed. The paper concludes with an experimental study on currently available equipment, to translate the generic conclusions into their current implications and trade-offs. Copyright

xStreamer: modular multimedia streaming

The xStreamer intends to be a flexible and modular open source streamer. The selection of current open source streamers which support both video and audio is limited, with VLC Media Player, Darwin Streaming Server and Helix DNA Server being the foremost solutions. The xStreamer distinguishes itself by providing a modularity that goes beyond the mere modular programming offered by the current open source solutions and that manifests itself in how the user controls and configures the streamer.

Tengu: An Experimentation Platform for Big Data Applications

Big data applications have stringent service requirements for scalability and fault-tolerance and involve high volumes of data, high processing speeds and large varieties of database technologies. In order to test big data management solutions, large experimentation facilities are needed, which are expensive in terms of both resource cost and configuration time. This paper presents Tengu, an experimentation platform for big data applications that can automatically be instantiated on GENI (US federation of test beds) and Fed FIRE (EU federation of test beds)compatible test beds. Tengu allows for automatic deployments of several data processing, storage and cloud technologies, including Hadoop, Storm and Open Stack. The paper discusses the Tengu architecture, the Tengu-as-a-service approach and a demonstration of an automated instantiation of the Tengu experimentation suite on the Virtual Wall, a large-scale Emulab testbed at the Minds research institute in Europe.

An end to end QoS discovery architecture embedded in a TINA based multimedia platform

In this paper we envisage the issue of quality of service (QoS) management for multimedia services as an end to end QoS discovery problem. With this perception as a basis, we designed and implemented a layered QoS management architecture which handles QoS from the users perspective, as well as from the end systems and the networks perspective. The architecture is decomposed into three layers. First there is the QoS specification, presentation and parameterization layer at which an end user is able to specify his/her QoS requirements in a comprehensible and qualitative way, and at which these QoS requirements are translated into parameterized terminal capabilities. Secondly, there is the QoS matching and negotiation layer at which the parameterized QoS capabilities of different terminal end systems are marched and compared in order to search for a QoS equilibrium. Finally, there is the QoS implementation layer which implements the resolved QoS equilibrium in the network and in the terminals. This generic architecture, which allows a de-abstraction of user defined QoS, has been implemented in the context of a CORBA based TINA platform.