Blekinge Institute of Technology
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On social interaction metrics : social network crawling based on interestingness
No full textWith the high use of online social networks we are entering the era of big
data. With limited resources it is important to evaluate and prioritize
interesting data. This thesis addresses the following aspects of social network
analysis: efficient data collection, social interaction evaluation and user
privacy concerns.
It is possible to collect data from online social networks via their open APIs.
However, a systematic and efficient collection of online social networks data
is still challenging. To improve the quality of the data collection process,
prioritizing methods are statistically evaluated. Results suggest that the
collection time can be reduced by up to 48% by prioritizing the collection of
posts.
Evaluation of social interactions also require data that covers all the
interactions in a given domain. This has previously been hard to do, but the
proposed crawler is capable of extracting all social interactions from a given
page. With the extracted data it is for instance possible to illustrate
indirect interactions between different users that do not necessarily have to
be connected. Methods using the same data to identify and cluster different
opinions in online communities have been developed. These methods are evaluated
with the too Linguistic Inquiry and Word Count.
The privacy of the content produced; and the users’ private information
provided on social networks is important to protect. Users must be aware of the
consequence of posting in online social networks in terms of privacy. Methods
to protect user privacy are presented.
The proposed crawler in this thesis has, over the period of 20 months,
collected over 38 million posts from public pages on Facebook covering: 4
billion likes and 340 million comments from over 280 million users. The
performed data collection yielded one of the largest research dataset of social
interactions on Facebook today, enabling qualitative research in form of social
network analysis
A General Architecture For Developing A Sustainable Elderly Care E-Health System
No full textBased on some identified problems and challenges to the current healthcare
system, this paper proposes architecture for developing e-health system to meet
the challenges and resolve some problems. The architecture is based on a solid
theoretical model of human activity, and it has properties such as
sustainability, generality, and expandability. We demonstrate the properties of
the architecture through an ongoing research project. We concluded that this
architecture can be widely used to integrate various small scale applications
of e-health systems and to resolve some current design problems such as
interoperability and knowledge sharing
SAR Resolution Enhancement with Circular Aperture in Theory and Empirical Scenario
No full textSAR systems synthesizing circular apertures have been shown to result in better
spatial resolutions than the ones synthesizing linear apertures. The paper
presents an investigation about the enhancement of SAR spatial resolutions with
the use of circular aperture. A comparison between the spatial resolutions
obtained with a SAR system synthesizing a circular aperture and with the same
SAR system synthesizing a linear aperture is therefore carried out. The
studying results are verified by the experimental SAR data set provided by the
experimental ground-based SAR system of Blekinge Institute of Technology (BTH
GB-SAR)
Exploratory Analysis of a GGSN’s PDP Context Signaling Load
No full textThis paper takes an exploratory look on control plane signaling in a mobile
cellular core network. In contrast to most contributions in this field, our
focus does not lie on the wireless or user-oriented parts of the network, but
on signaling in the core network. In an investigation of core network data we
take a look at statistics related to GTP tunnels and their signaling. Based on
the results thereof we propose a definition of load at the GGSN and create an
initial load queuingmodel.We find signs of user devices putting
burden on the core network through their behavio
Reflektera mera – erfarenheter från projektledning i professionsutbildning
No full textArtikeln behandlar erfarenheter från de tre första omgångarna av kursen Ledning
och organisation (15 hp) på masterprogrammet i fysisk planering (120 hp).
Lärarlaget består av en lärare från fysisk planering (kursansvarig) och en
lärare från industriell ekonomi – ett exempel på samarbete inom fakulteten för
teknikvetenskaper på Blekinge Tekniska Högskola. Med denna kurs kan
projektledningens teori och praktik behandlas på ett systematiskt sätt i
utbildningen. Syftet är att beskriva den högskolepedagogiska ansatsen i kursen
och att diskutera om och i så fall hur upplägget kan bidra till studenternas
lärande, utifrån målet att studenterna ska vara aktivt kunskapssökande och
utveckla sitt kritiska tänkande. Masterprogrammet är en tvåårig utbildning på
avancerad nivå som förbereder studenterna för kvalificerad yrkesverksamhet, där
projektledning och projektarbete är vanligt förekommande. Ett viktigt
pedagogiskt mål är därför att i kursen Ledning och Organisation systematiskt
erbjuda fördjupade förutsättningar för studenternas utveckling i att hantera
komplexiteten i projektsituationer utifrån det egna professionsfältet.
Utgångspunkt för konstruktion av lärsituationer har varit Barnetts teoretiska
perspektiv, presenterat i Improving Higher Education från 1992, med målet att
utveckla studentens kritiska tänkande genom reflektion. Artikeln beskriver hur
de av Barnett beskrivna fyra områdena för att utveckla kritiskt tänkande
används i kursen; kommunikativ handling [action], ömsesidigt engagemang
[interpersonal engagement], reflektion i handling [reflection-in-action] och
kunskapsanvändning [knowledge-in-action]. Barnetts begrepp är en
vidareutveckling av Schöns idéer om The reflectictive Practitioner från 1983.
Exempel på studentreflektioner under kursens gång illustrerar hur studenterna
har reagerat på kursupplägget
Design and Implementation of a Maritime Traffic Modeling and Anomaly Detection Method
No full textNowadays ships are usually equipped with a system of marine instruments, one of
which is an Automatic Identification System (AIS) transponder. The availability
of the global AIS ship tracking data opened the possibilities to develop
maritime security far beyond the simple collision prevention. The research work
summarized in this thesis explores this opportunity, with the aim of developing
an intuitive and comprehensible method for traffic modeling and anomaly
detection in the maritime domain.
The novelty of the method lays in employing the technique of artificial
potential fields. The general idea is for the potentials to represent typical
patterns of vessels' behaviors. A conflict between potentials, which have been
observed in the past, and the potential of a vessel currently in motion,
indicates an anomaly.
The developed potential field based method has been examined using a web-based
anomaly detection system STRAND (for Seafaring TRansport ANomaly Detection).
Its applicability has been demonstrated in several publications, examining its
scalability, modeling capabilities and detection performance. The experimental
investigations led to identifying optimal detection resolution for different
traffic areas (open sea, harbor and river), and extracting traffic rules, e.g.,
with regard to speed limits and course, i.e., right-hand sailing rule. The
map-based display of modeled traffic patterns and detection cases has been
analyzed as well, using several demonstrative cases. The massive AIS database
created for this study, together with a dataset of real traffic incidents,
provides an abundance of challenges for future studies
On Enhancement and Quality Assessment of Audio and Video in Communication Systems
No full textThe use of audio and video communication has increased exponentially over the
last decade and has gone from speech over GSM to HD resolution video conference
between continents on mobile devices. As the use becomes more widespread the
interest in delivering high quality media increases even on devices with
limited resources. This includes both development and enhancement of the
communication chain but also the topic of objective measurements of the
perceived quality. The focus of this thesis work has been to perform
enhancement within speech encoding and video decoding, to measure influence
factors of audio and video performance, and to build methods to predict the
perceived video quality.
The audio enhancement part of this thesis addresses the well known problem in
the GSM system with an interfering signal generated by the switching nature of
TDMA cellular telephony. Two different solutions are given to suppress such
interference internally in the mobile handset. The first method involves the
use of subtractive noise cancellation employing correlators, the second uses a
structure of IIR notch filters. Both solutions use control algorithms based on
the state of the communication between the mobile handset and the base station.
The video enhancement part presents two post-filters. These two filters are
designed to improve visual quality of highly compressed video streams from
standard, block-based video codecs by combating both blocking and ringing
artifacts. The second post-filter also performs sharpening.
The third part addresses the problem of measuring audio and video delay as well
as skewness between these, also known as synchronization. This method is a
black box technique which enables it to be applied on any audiovisual
application, proprietary as well as open standards, and can be run on any
platform and over any network connectivity.
The last part addresses no-reference (NR) bitstream video quality prediction
using features extracted from the coded video stream. Several methods have been
used and evaluated: Multiple Linear Regression (MLR), Artificial Neural Network
(ANN), and Least Square Support Vector Machines (LS-SVM), showing high
correlation with both MOS and objective video assessment methods as PSNR and
PEVQ. The impact from temporal, spatial and quantization variations on
perceptual video quality has also been addressed, together with the trade off
between these, and for this purpose a set of locally conducted subjective
experiments were performed
Performance Comparison of KVM, VMware and XenServer using a Large Telecommunication Application
No full textOne of the most important technologies in cloud computing is virtualization.
This paper presents the results from a performance comparison of three
well-known virtualization hypervisors: KVM, VMware and XenServer. In this
study, we measure performance in terms of CPU utilization, disk utilization and
response time of a large industrial real-time application. The application is
running inside a virtual machine (VM) controlled by the KVM, VMware and
XenServer hypervisors, respectively. Furthermore, we compare the three
hypervisors based on downtime and total migration time during live migration.
The results show that the Xen hypervisor results in higher CPU utilization and
thus also lower maximum performance compared to VMware and KVM. However, VMware
causes more write operations to disk than KVM and Xen, and Xen causes less
downtime than KVM and VMware during live migration. This means that no single
hypervisor has the best performance for all aspects considered here
On Physical Layer Security for Reactive DF Cognitive Relay Networks
No full textThis paper analyzes the physical layer security for
cognitive relay networks under the peak interference power
constraint of the primary user receiver. In particular, a secondary user (SU)
transmitter communicates with an SU receiver through the help of multiple
secondary relays (SRs) using a decode-and- forward (DF) protocol. There exist
multiple eavesdroppers (EAVs) who illegally listen to the secondary network
communication. We consider a reactive DF scheme, and only the SRs that satisfy
a decoding threshold participate in the relay selection. Analytical expressions
of the probability of existence of secrecy capacity and secrecy outage
probability are obtained. Numerical results are provided to evaluate the impact
of the number of SRs, number of EAVs and channel mean powers on the secondary
system security. We also investigate the effect of the interference from the
primary network to the secondary network performance. Moreover, the performance
of proactive DF is analyzed for the purpose of comparison
Multi–Level Environmental Governance: The Case of Wind Power Development in Sweden
No full textAt national policy level in Sweden, the importance of development of wind power
is emphasized. However, the actual implementation is highly dependent on local
permit giving for windmills. The legislation governing the permit giving has
been revised in an attempt to make the local processes faster and to shift the
permit process towards a more regional environmental process as opposed to a
more plan-based municipal process. By tradition in Sweden, the local, municipal
level has had a strong mandate in land use planning which is often referred to
as the “the municipal planning monopoly”, which means that there is a tension
whenever a legal proposal seeks to diminish this “plan monopoly”. The legal
investigation suggesting changes in the law on permit-giving stressed the need
for strengthening the regional assessment, which led to a compromise called the
“municipal veto-right”, where the regional environmental permit needs a formal
approval from the municipality for the permit process to continue. This study
investigates both the legal development of the so-called veto-right as well as
what it empirically has led to, and how it is perceived by the industry as well
as concerned parties. For this reason, a sample of 30 regional permit cases has
been collected, and a limited number of interviews have been conducted with
judges in appeal courts and regional handling officers assessing turbine
applications. The results indicate that the industry sees the “veto” as leading
to problematic uncertainty in the process at regional level and, therefore,
prefer to keep the applications at a level that entitles them to use the
municipal permit system which is determined by height and number of turbines.
This is a consequence directly opposite to what the legal commission aimed for
when revising the legal system