Markus Fiedler

Markus Fiedler
Blekinge Institute of Technology | BTH · Laboratory of Communication and Computer Systems (CCS)

22.02
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Research items (192)
Preprint
Machine Learning based Quality of Experience (QoE) models potentially suffer from over-fitting due to limitations including low data volume, and limited participant profiles. This prevents models from becoming generic. Consequently, these trained models may under-perform when tested outside the experimented population. One reason for the limited da...
Article
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ABSTRACT Background: Several models suggest how the qualities of a product or service influence user satisfaction. Models such as the Customer Satisfaction Index (CSI), Technology Acceptance Model (TAM), and Delone and McLean Information Systems Success demonstrate those relations and have been used in the context of health information systems. Ob...
Conference Paper
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In this paper, we investigate session-related per-formance statistics of a Web-based Real-Time Communication(WebRTC) application called appear.in. We explore the char-acteristics of these statistics and explore how they may relateto users’ Quality of Experience (QoE). More concretely, wehave run a series of tests involving two parties and accord-in...
Article
To cope with the rapid growth of multimedia applications that requires dynamic levels of quality of service (QoS), cross-layer (CL) design, where multiple protocol layers are jointly combined, has been considered to provide diverse QoS provisions for mobile multimedia networks. However, there is a lack of a general mathematical framework to model s...
Article
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In real-time video streaming, video quality can be degraded due to network performance issues. Among other artefacts, video freezing and video jumping are factors that influence user experience. Service providers, operators and manufacturers are interested in evaluating the quality of experience (QoE) objectively because subjective assessment of Qo...
Conference Paper
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While the modeling of QoE has made significant advances over the last couple of years, currently existing models still lack an integration of user behavior aspects and user context factors along with the consideration of appropriate temporal scales. Therefore, the goal of this paper is to present a comprehensive QoE and user behavior model providin...
Article
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This report provides an overview of the program, discussions and outcomes of Dagstuhl Seminar 15022 "Quality of Experience: From Assessment to Application", which took place from 4 - 7 January 2015 at Schloss Dagstuhl - Leibniz Center for Informatics. The seminar and the challenges that were addressed have their roots in the earlier Dagstuhl Semina...
Article
Mobile connectivity typically exhibits on-off behavior, i.e. phases of undisturbed data transmission are interrupted by outages. Recent matching efforts have shown that the durations of the on- and off-phases can be matched by exponential distributions. The resulting exponential on-off models allow for elegant close-form solutions for performance m...
Article
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In this paper we propose a methodological framework for modeling Quality of Experience (QoE) for media services in a generic manner. We consider QoE as a multi-dimensional concept dependent on several factors related to the service itself, its resource requirements, its users, and its context of use. As a first step, we group these factors into fou...
Chapter
Cognitive radio technology is a key concept suggested to be part of the so-called 5th generation mobile networks. The basic idea is to allow unlicensed users access to licensed spectrum, under the condition that the interference perceived by the licensed users is minimal. An important aspect is the need to develop highly specialized and efficient m...
Conference Paper
The most energy-consuming applications in battery life-constrained smartphones are the ones that comprise data transmission, especially via the 3G interface. Scheduling download activities on smartphones is especially necessary, if there are multiple asynchronous downloads scattered over a long duration. The latter scenario highly increases the ene...
Chapter
Wireless networks have become more and more popular because of ease of installation, ease of access, and support of smart terminals and gadgets on the move. In the overall life cycle of providing green wireless technology, from production to operation and, finally, removal, this chapter focuses on the operation phase and summarizes insights in ener...
Conference Paper
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The time-critical tasks on the Internet are increasing. The delays in these tasks can have severe implications on the Quality of Experience (QoE) of a service. Therefore, networks require smart user-centric resource management mechanisms to reduce the impact of these delays on QoE. For this, a better understanding of the user preferences with regar...
Chapter
This chapter presents an overview of a set of recently proposed QoE-based management approaches that all try so resolve a central dilemma: maximizing user satisfaction while at the same time maximizing resource efficiency and economy. To this end, it first builds bridges between recent approaches towards QoE-based Network Management and standardize...
Article
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The usage of network-demanding applications is growing rapidly such as video streaming on mobile terminals. However, network and/or service providers might not guarantee the perceived quality for video streaming that demands high packet transmission rate. In order to satisfy the user expectations and to minimize user churn, it is important for netw...
Conference Paper
Brief episodes of network faults and performance issues adversely affect the user Quality of Experience (QoE). Besides damaging the current opinions of users, these events may also shape user's future perception of the service. Therefore, it is important to quantify the impact of such events on QoE over time. In this paper, we present our findings...
Conference Paper
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One of the most influencing factors on the overall end-user perceived quality from applications and services, i.e., QoE, running on the smartphones is their limited battery life. Particular cloud-based applications/services on the smartphone with a constrained battery life might consume high energy even when the smartphone is in screen-OFF state. T...
Conference Paper
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Video streaming and multimedia applications are getting popular with the growth of networks. In real-time video streaming, video quality can be degraded due to network performance issues. Among other artifacts, freezing and frame dropping are factors that influence user experience. Service providers, operators, and researchers are interested to mea...
Article
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Mobile devices with ever-increasing functionality and the ubiquitous availability of wireless communication networks are driving forces behind innovative mobile applications enriching our daily life. One of the performance measures for a successful application deployment is the ability to support application-data flows by heterogeneous networks wit...
Conference Paper
Real-time video streaming suffer from bandwidth limitation that are unable to handle the high amount of video data. To reduce the amount of data to be streamed, we propose an adaptive technique to crop the important part of the video frames, and drop the part that are outside the important part; this part is called the Region of Interest (ROI). The...
Conference Paper
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The rapid migration towards wireless connectivity means that the radio spectrum must be efficiently utilized to conserve capacity and to avoid overcrowding, particularly in densely populated areas. Towards this goal, cognitive radio technology is a key concept. The basic idea is to allow unlicensed users access to licensed spectrum, under the condi...
Conference Paper
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Subjective performance of smartphone-based high bandwidth- and energy-demanding applications and services such as video streaming, are highly influenced by the temporal impairments perceived by the user at the user interface; and the application's energy consumption patterns. Therefore, we study the influence of the anomalies detected by objective...
Conference Paper
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Comprehensive communication in cognitive radio networks is an important research topic within the scope of empowering cognitive radio functionality in beyond-4G mobile networks. Providing communication for secondary users without interference with primary users is an ambitious task, which requires innovative management architecture designs and rout...
Article
Today, many people share personal information through online social networks. While these networks offer tremendous facilities to share one's life with family, friends and the outer world, users are also exposed to the risk to get their accounts compromized, with consequences for their professional and private lives. A strong password can help to e...
Article
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In real time video streaming, the frames must meet their timing constraints, typically specified as their deadlines. Wireless networks may suffer from bandwidth limitations. To reduce the data transmission over the wireless networks, we propose an adaption technique in the server side by extracting a part of the video frames that considered as a Re...
Conference Paper
Streaming real time video over wireless networks cannot guarantee that all the frames could meet their deadlines. Wireless networks may suffer from bandwidth limitations. To reduce the streaming data over wireless networks, we propose a technique to identify, and extract the Region Of Interest (ROI), and drop the non-ROI from the frames that are be...
Article
ABSTRACT The vision towards the Network of the Future cannot be separated from the fact that today's networks, and networking services are subject to sophisticated and very effective attacks. When these attacks first appeared, spoofing and distributed denial-of-service attacks were treated as apocalypse for networking. Now, they are considered mode...
Conference Paper
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End user quality perception in the context of Internet applications is often characterized by waiting times before service consumption as well as interruptions during service consumption. In particular in case of bad network conditions, network and service providers have to trade off between these two impairment types, i.e. between the devil and th...
Conference Paper
A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data...
Conference Paper
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Evaluating video Quality of Experience (QoE) on a mobile phone has not yet been studied much. It is common that the data collected through user studies in mobile platform involves high fluctuation of user ratings without obvious reasons related to variation in network level. User disparity, user's various intermediate or previous experiences, video...
Conference Paper
This paper presents a queue simulation of a remote laboratory based on the VISIR Open Lab Platform designed at Blekinge Institute of Technology. A model of this VISIR laboratory and statistical distributions of how users interact with the system based on real log files are presented. The system is then simulated in order to determine how many concu...
Conference Paper
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The Darwin Streaming Server employs stream thinning and transmission rate adaptation for traffic and congestion control. We investigate the relation of video content with the stream thinning and transmission rate adaptation process under 3GPP-adaptation. We observe that stream thinning is not only initiated upon fluctuation of network properties or...
Conference Paper
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Cognitive Radio Networks (CRNs) are expected to address and to resolve important technological and operational challenges of future networks, such as Dynamic Spectrum Access (DSA), routing in heterogeneous networks and provision of Quality of Experience (QoE) for different applications. Accordingly, a number of new terminal and network functionalit...
Conference Paper
In this paper, we examine the delay performance in cognitive radio networks (CRNs) over general fading channels where secondary users are allowed to simultaneously access the spectrum licensed by primary users. In particular, subject to the peak interference power constraint, we investigate the effect of general fading channels on the delivery dela...
Conference Paper
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In this work, we analyze from passive measurements the correlations between the user-induced interruptions of TCP connections and different end-to-end performance metrics. The aim of this study is to assess the possibility for a network operator to take into account the customers' experience for network monitoring. We first observe that the usual c...
Article
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The paper advances a new architecture for seamless roaming, which is implemented at the application layer. This architecture is subject for the research projects PERIMETER and MOBICOME, recently granted by the EU STREP FP7 and EUREKA, respectively. The research challenges are on mobility management, security, QoE management, overlay routing, no...
Article
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With the growth of the mobile internet, the popularity of multimedia services and applications have increased rapidly. As a result, end-users become quality-conscious. To fulfill the users' expectations, the study of quality of experience (QoE) is becoming very important for both researchers and service providers. This paper analyses the impact on...
Article
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Increasingly, we use mobile applications and services in our daily life activities, to support our needs for information, communication or leisure. However, user acceptance of a mobile application depends on at least two conditions: the application's perceived experience, and the appropriateness of the application to the user¿s context and needs. H...
Article
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The use of end-to-end communication systems as a medium of delivery for electronic healthcare (eHealth) services is considered to be uncertain, with respect to its reliability leading to hesitation in acceptance of such services. There exist different influential dimensions that pose stringent requirements on end-to-end communication systems, influ...
Conference Paper
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The smartphone usage nearly tripled in 2011 according to Cisco Virtual Networking Index. There is a high demand of energy for using popular mobile applications, which run on smartphones with limited battery life. Video streaming applications are widely used on mobile devices, and their high power consumption exhibits high variance during a live str...
Conference Paper
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Internet traffic monitoring and analysis have been playing a crucial role in understanding and characterizing user behavior on the web. In particular, ON-OFF models capture the essential phases of user communication with web servers. The OFF phases reflect both deliberate and accidental gaps in the traffic flow. In this paper, we present a passive...
Article
Real-time video streaming over wireless channel has become an important issue due to the limited bandwidth that is unable to handle the flow of information of the video frames. The characteristics of wireless networks in terms of the available bandwidth, frame delay, and frame losses cannot be known in advance. As the effect of that, the user may n...
Article
Many emerging smart applications and services employ Web technology, and users nowadays surf the Web from any device via any kind of access network. Typically, high page latencies trigger users to abort ongoing transfers, resulting in the abrupt terminations of the TCP connections. This paper presents a systematic study of the termination process o...
Conference Paper
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In this work, we present a systematic study of how the traffic of different transport protocols (UDP, TCP and ICMP) is treated, in three operational Swedish 3G networks. This is done by studying the impact that protocol and packet size have on the one-way-delay (OWD) across the networks. We do this using a special method that allows us to calculate...
Conference Paper
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Quality of Experience (QoE) has gained enormous attention during the recent years. So far, most of the existing QoE research has focused on audio and video streaming applications, although HTTP traffic carries the majority of traffic in the residential broadband Internet. However, existing QoE models for this domain do not consider temporal dynamic...
Conference Paper
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Mobile applications and services increasingly assist us in our daily life situations, fulfilling our needs for information, communication, entertainment or leisure. However, user acceptance of a mobile application depends on at least two conditions; the application's perceived Quality of Experience (QoE) and the appropriateness of the application t...
Conference Paper
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Traffic shapers are used by researchers to emulate the behavior of networks and applications in test environments, typically with user-defined traffic shaping parameters such as throughput and loss. Also, traffic shapers are used for the enforcement of SLA, so they are of interest for Internet Service Providers. However, output given by traffic sha...
Conference Paper
Quality of Experience (QoE) combines non-technical parameters such as user perception, experience and expectations with technical parameters such as application- and network-level Quality of Service (QoS). For service or network providers, it is important to understand the quantitative relationship between QoE and these technical parameters in orde...
Conference Paper
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The ASPECTS project considered an underlying dynamic spectrum access radio network, spectrum sensing technology and techniques, and spectrum sharing policies and rules and addressed vulnerabilities in all spectrum sharing phases, i.e. spectrum monitoring, negotiation, dissemination of access rules and sharing implementation. In the following sectio...
Article
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Streaming video over a wireless network faces several challenges such as high packet error rates, bandwidth variations, and delays, which could have negative effects on the video streaming and the viewer will perceive a frozen picture for certain durations due to loss of frames. In this study, we propose a Time Interleaving Robust Streaming (TIRS)...
Chapter
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Application-perceived throughput plays a major role for the performance of networked applications and user experience and thus, for network selection decisions. To support the latter, this tutorial paper investigates the process of user-perceived throughput in GPRS and UMTS systems seen over rather small averaging intervals, based on test traffic m...
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