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Inferring User-perceived Performance of Network by Monitoring TCP Interruptions
No full textThe fluctuating performance of wireless and mobile networks has triggered the
need for smart algorithms to assess the user perception, resulting from the
quality of network services. While efforts have been done to model the user
experience resulting from the network performance, there is still the need for
practical methods to assess the user-perceived performance, in the real
environment. In this work, we present a set of criteria to observe the user
behavior on the Web, passively from the network-level. The criteria are based
on the monitoring of TCP control flags and HTTP requests. Thus, information
about user actions performed in the web browser can be inferred by monitoring
the TCP termination flags and by keeping track of the HTTP requests. Along the
way, we also present some anomalies observed in the TCP connection termination
process, which may result in performance degradation of Web transfers
Studying the challenges in assessing the perceived quality of mobile-phone based video
No full textEvaluating 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 bitrate, and the objective measure
of criticality are a few of the reasons that need to be identified with a
well-designed user experiment. We present an experiment procedure to understand
better the perceived quality of video in mobile platform. First, we investigate
the reliability of the data, and identify unreliable users. Then, we
investigate the psychological influence factors of previous experiences on the
recent perceived quality known as the memory effect, and the influence of the
bitrate on the time it takes for users to react and evaluate the video quality,
i.e., user response time
E-Mail Prioritization using Online Social Network Profile Distance
No full textOnline Social Networks (OSNs) provide new ways for people to communicate with
one another and to share content. OSNs have become quite popular among the
general population. Their rapid growth has raised concerns about privacy and
security on the one hand but increased efficiency in solving everyday online
tasks on the other hand. Many predict that the OSNs of today provide a glimpse
of the future Internet infrastructure. Whether or not that will be true is
difficult to say but what is certain is that privacy, integrity, and security
issues related to the world wide web will be as important then as now. This
article presents a method for improving efficiency and security of E-mail
applications by focusing on one of the core concepts of OSNs; the user profile,
which both includes private and public information that the user shares to
different parties and the social interaction between users.We present a generic
method for comparing user profiles, by measuring the distance between user
profile or user vectors and an algorithm that uses this method for prioritizing
the E-mail inbox. We report on an experimental case in which the proposed
method is used in conjunction with social information from Facebook to
demonstrate the applicability as well as to motivate its theoretical
foundation
A Spectrum Decision Support System for Cognitive Radio Networks
No full textCognitive Radio Networks (CRNs) offer a promising capability of alleviating the
problem of spectrum insufficiency. In CRNs, the licensed spectrum channels are
either exclusively reserved for licensed users or temporarily used by
unlicensed users. The requirement for unlicensed users is to not harmfully
impair the licensed users transmissions. Because of this, the unlicensed users
must solve the task to decide which available channels should be selected. The
selection process is often referred to as spectrum decision, with the aim to
optimize the transmission performance of unlicensed users.
A support system for CRNs is introduced, which is called Spectrum Decision
Support System (SDSS). SDSS provides an intelligent spectrum decision strategy
that integrates different decision making algorithms and takes into account
various channel characterization parameters. The objective is to develop a
scientific framework for decision making in CRNs, which involve theoretical
analysis, simulation evaluation and practical implementation. Three important
components of SDSS are discussed: 1) setting up an overlay decision maker, 2)
prediction based spectrum decision strategy and 3) queuing modeling of CRNs.
The reported results indicate the feasibility of the suggested algorithms
Amplify-and-Forward Relay Assisting both Primary and Secondary Transmissions in Cognitive Radio Networks over Nakagami-m Fading
No full textIn this paper, we study the performance for the primary and secondary
transmissions in cognitive radio networks
where the amplify-and-forward (AF) secondary relay helps to transmit the
signals for both the primary and secondary transmitters over independent
Nakagami-m fading. First, we derive exact closed-form expressions for outage
probability and symbol error rate (SER) of the primary network. Then, we derive
an exact closed-form expression for outage probability and a closed-form
expression of a tight upper bound for SER of the secondary network.
Furthermore, we also make a comparison for the performance of the primary
system with and without the
help of the secondary relay
Subjective Quality Assessment of H.264/AVC Encoded Low Resolution Videos
No full textAdvancements in the video processing area have been proliferated by services
that require low delay. Such services
involve applications being offered at various temporal and spatial resolutions.
It necessitates to study the impacts of related video coding conditions upon
perceptual quality. But most of studies concerned with quality assessment of
videos affected by coding distortions lack in variety of spatio-temporal
resolutions. This paper presents a work done on quality assessment of videos
encoded by state-of-the-art H.264/AVC standard at different bitrates and frame
rates. Overall, 120 test scenarios for video sequences having different spatial
and temporal spectral information were studied. The used coded bistreams in
this work and the corresponding subjective assessment scores have been made
public for the research community to facilitate further studie
Proposed Core Services for the Deployment of Intelligent Truck Parking
No full textThis article suggest Transport Telematic Services (TTSs) to facilitate the
realization of Intelligent Truck Parking (ITP) concept i.e. ITP core services
e.g. a service that can support real time reservation of truck parking space
using for instance mobile phone messaging capabilities. We consider ITP to
include the collection, processing and delivery of information about Truck
Parking Areas (TPAs) that may take place during the planning and execution of
transportation services. A key feature for ITP core services is to achieve
efficient information exchange related to TPA so as to improve the overall
performance of the transport system. We suggest core services seen to have a
potential for achieving ITP. Our suggestions are based on studying “what” kind
of information exchanges among TPA stakeholders “when” and “where” the
information is exchanged in relation to transport related challenges that are
addressed with such information. Hence we suggest Truck Parking facility
Utilization (TPU), Goods and Vehicle Safety assurance information (GVS),
Parking Location Guidance (PLG) and Parking Reservation (PAR), as ITP core
services
A Comparative Evaluation of Re-scheduling Strategies for Train Dispatching during Disturbances
No full textRailway traffic disturbances occur and train dispatchers make re-scheduling
decisions in order to reduce the delays. In order to support the dispatchers,
good rescheduling strategies are required that could reduce the delays. We
propose and
evaluate re-scheduling strategies based on: (i) earliest start time, (ii)
earliest track release time, (iii) smallest buffer time, and (iv) shortest
section runtime. A comparative evaluation is done for a busy part of the
Swedish railway network. Our results indicate that strategies based on earliest
start time and earliest track release time have the best average performance
A Limit Study of Thread-Level Speculation in JavaScript Engines --- Initial Results
No full textJavaScript is a programming language for interactive clientside
functionalities in web applications. It is a sequential pro-
gramming language, so it cannot take advantage of multicore
processors. Previously Thread-Level Speculation has been
used to take advantage of multicore processors for JavaScript
execution in web applications with promising results execu-
tion time wise, but with a large memory overhead. In this
study we have evaluated the effects of limiting the amount
of memory, the number of threads and the depth of specula-
tion in Thread-Level Speculation. Our results indicate that
we can tune these parameters to improve execution time and
reduce the memory overhead