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Performance of HTTP Video Streaming Under Different Network Conditions
No full textThe Internet video sharing services have been gaining importance and increasing
their share in the multimedia market. In order to compete effectively and
provide broadcast television with a comparable level of quality, the Internet
video should fulfil stringent quality of service (QoS) constraints. However, as
the Internet video is based on packet transmission, it is influenced by delays,
transmission errors, data losses and bandwidth limitations which can have a
devastating influence on the perceived quality of the multimedia content. There
are many works which describe the impact of network impairments on the Internet
video. Nevertheless, little is known about how network conditions influence the
video streamed by the currently popular services such as YouTube, where video
is transmitted over reliable TCP/HTTP protocols. Therefore using a network
simulator, we conducted an experimental evaluation of theHTTP based video
transmission analysing how the network impairments mentioned above influence
the streamed video. The experiments were validated against a network emulator
supplied with real network traces. As a result of this work, we can state that
the buffering strategies implemented by a video player are in many cases able
to mitigate unfavourable network conditions what allow to play the streamed
video smoothly. The results may serve Internet Service Providers so that they
could tune their network characteristics in order to match the demand from HTTP
video
Software Development in Startup Companies: A Systematic Mapping Study
No full textContext: Software startups are newly created companies with no operating
history and fast in producing cutting-edge technologies. These companies
develop software under highly uncertain conditions, tackling fast-growing
markets under severe lack of resources. Therefore, software startups present an
unique combination of characteristics which pose several challenges to software
development activities.
Objective: This study aims to structure and analyze the literature on software
development in startup companies, determining thereby the potential for
technology transfer and identifying software development work practices
reported by practitioners and researchers.
Method: We conducted a systematic mapping study, developing a classification
schema, ranking the selected primary studies according their rigor and
relevance, and analyzing reported software development work practices in
startups.
Results: A total of 43 primary studies were identified and mapped, synthesizing
the available evidence on software development in startups. Only 16 studies are
entirely dedicated to software development in startups, of which 10 result in a
weak contribution (advice and implications (6); lesson learned (3); tool (1)).
Nineteen studies focus on managerial and organizational factors. Moreover, only
9 studies exhibit high scientific rigor and relevance. From the reviewed
primary studies, 213 software engineering work
practices were extracted, categorized and analyzed.
Conclusion: This mapping study provides the first systematic exploration of the
state-of-art on software startup research. The existing body of knowledge is
limited to a few high quality studies. Furthermore, the results indicate that
software engineering work practices are chosen opportunistically, adapted and
configured to provide value under the constrains imposed by the startup
context
RFID - Hybrid Scene Analysis-Neural Network System for 3D Indoor Positioning optimal system arrangement approach
No full textThe purpose of this research is to find an optimal number and configuration of
readers in RFID based 3D Indoor Positioning System. The system applies a Hybrid
Scene Analysis - Neural Network algorithm to estimate target's position with a
desired accuracy. The system's accuracy and cost depend on a number of utilized
readers and their arrangement. Readers' deployment is crucial for the
localization accuracy too. The system optimization enhances the system
cost-efficiency. The arrangement analysis was based on simulations and
validated by physical experiment. The results of this research define a
trade-off between a number of readers and their deployment and the system
performance in terms of localization accuracy
Cloud Computing for Interoperability in Home-Based Healthcare
No full textThe care of chronic disease has become a main challenge for healthcare
institutions around the world. As the incidence and prevalence of chronic
diseases continue to increase, traditional hospital-based healthcare is less
able to meet the needs of every patient. Treating chronic disease heavily
depends on the patient’s daily behaviors, so patient-centered healthcare is
encouraged. To improve patients’ quality of life, moving the base of healthcare
from hospital to home is imperative. Home-based chronic disease care involves
many different healthcare organizations and healthcare providers. Therefore,
interoperability is a key approach to provide efficient and convenient
home-based healthcare services.
This thesis aims to reveal the interoperability issues in the current
healthcare system and to point out an appropriate technical solution to
overcome them. We start with collecting perspectives from both healthcare
providers and healthcare recipients through interviews and online surveys to
understand the situations and problems they face. In our research study, we
mainly use two current techniques―peer-to-peer (P2P) networks and cloud
computing―to design prototypes for sharing healthcare data, developing both a
P2P-based solution and a cloud-based solution. Comparing these two techniques,
we found the cloud-based solution covered most of the deficiencies in
healthcare interoperability. Although there are different types of
interoperability, such as pragmatic, semantic and syntactic, we explored
alternative solutions specifically for syntactic interoperability.
To identify the state of the art and pinpoint the challenges and possible
future directions for applying a cloud-based solution, we reviewed the
literature on cloud-based eHealth solutions. We suggest that a hybrid cloud
model, which contains access controls and techniques for securing data, would
be a feasible solution for developing a citizen-centered, home-based healthcare
system. Patients’ healthcare records in hospitals and other healthcare centers
could be kept in private clouds, while patients’ daily self-management data
could be published in a trusted public cloud. Patients, as the owners of their
health data, should then decide who can access their data and the conditions
for sharing.
Finally, we propose an online virtual community for home-based chronic disease
healthcare―a cloud-based, home healthcare platform. The requirements of the
platform were mainly determined from the responses to an online questionnaire
delivered to a target group of people. This platform integrates healthcare
providers and recipients within the same platform. Through this shared
platform, interoperability among different healthcare providers, as well as
with healthcare recipients’ self-management regimens, could be achieved
Social Challenges when Implementing Information Systems in a Swedish Healthcare Organization
No full textWhen the Swedish National IT Strategy for Health and Social Care was introduced
in 2006, intensive work started in implementing Information Systems (IS) in
Swedish healthcare organizations. To follow up on the requests for more
research with a combined socio-technical focus on challenges, the overall aim
of this thesis was to identify social challenges when implementing IS in a
Swedish healthcare organization. Furthermore, the aim was to understand the
impact of identified social challenges when implementing IS in this context by
putting them in an interdisciplinary Applied Health Technology theoretical
framework. Institutional ethnography and phenomenological hermeneutics
influenced the study design. Study 1 aimed to investigate different meanings of
accessibility when implementing Health Information Technology in everyday work
practice. The results indicate that accessibility depends on working routines,
social structures and patient relationship. When an IT strategy and interaction
in everyday work use the same word in different ways there will be
consequences. Study 2 sets out to describe experience-based reflections on
discharge planning as narrated by nursing staff in primary healthcare, along
with their concerns about how the introduction of video conferencing might
influence the discharge planning situation. It was found that there is a need
for improvement in communication and understanding between nursing staff at the
hospital and in primary healthcare. The aim of study 3 was to explore social
challenges when implementing IS in everyday work in a nursing context. Power
(changing the existing hierarchy, alienation), Professional identity (calling
on hold, expert becomes novice, changed routines), and Encounter (ignorant
introductions, preconceived notions) were categories presented in the findings.
The aim of study 4 was to explore and obtain a deeper understanding of how
identified social challenges have an influence on the implementation process of
IS, based on healthcare staff’s experiences on micro, meso and macro levels of
Swedish Healthcare organizations. It was found that the challenges were related
to the steps of putting into practice, making IS a part of everyday work
routine and establishing an identity in the implementation process. In the
thesis’s discussion, social challenges when implementing IS in Swedish
healthcare organizations and how they might be met and dealt with
constructively are further reflected upon in relation to the interdisciplinary
theoretical framework and as possible consequences of the modernity-era. This
thesis contributes to the starting up of a discussion of how ingrained
professional characteristics are important to feel secure of being part of an
established profession. If the characteristics are questioned, the whole
professional performance is threatened. One consequence of this insight is the
reinforcement of the realization that a basic understanding of IS and IS
implementation processes in healthcare organizations needs to be integrated in
to the construction of professional identity of nurses already from the start
in nursing education
Use and evaluation of simulation for software process education: a case study
No full textSoftware Engineering is an applied discipline and concepts
are difficult to grasp only at a theoretical level alone. In the context of a
project management course, we introduced and evaluated the use of software
process simulation (SPS) based games for improving students’ understanding of
software development processes. The effects of the intervention were measured
by evaluating the students’ arguments for choosing a particular development
process. The arguments were assessed with the Evidence-Based Reasoning
framework, which was extended to assess the strength of an argument. The
results indicate that students generally have difficulty providing strong
arguments for their choice of process models. Nevertheless, the assessment
indicates that the intervention of the SPS game had a positive impact on the
students’ arguments. Even though the illustrated argument assessment approach
can be used to provide formative feedback to students, its use is rather costly
and cannot be considered a replacement for traditional assessments
Managing Uncertainty and Ambiguity in Gates: Decision Making in Aerospace Product Development
No full textThis paper investigates decision making in the stage-gate process used by an
aerospace manufacturer. More specifically, it focuses on the way decision
makers deal with uncertainties and ambiguities when making decisions. The
stage-gate model was found to be a discussion trigger - a boundary negotiating
artefact - through which stakeholders bring issues to the table, reflect on
uncertainties, and decide in what areas more knowledge is needed. Managers
should be aware that the knowledge base might not always be perfect and should
make use of the sensemaking capabilities of the stage-gate model and the gate
meeting to mitigate and improve the knowledge base. This paper elaborates on
formalized knowledge-based criteria so as to support this evaluation of the
knowledge base
A dynamic hybrid antenna/relay selection scheme for the multiple-access relay channel
No full textWe propose a dynamic hybrid antenna/relay selection scheme for multiple-access
relay systems. The proposed scheme aims to boost the system throughput while
keeping a good error performance. By using the channel state information, the
destination node performs a dynamic selection between the signals provided by
the multi-antenna relay, located in the inter-cell region, and the relay nodes
geographically distributed over the cells. The multi-antenna relay and the
single-antenna relay nodes employ the decode-remodulate-and-forward and
amplify-and-forward protocols, respectively. Results reveal that the proposed
scheme offers a good tradeoff between spectral efficiency and diversity gain,
which is one of the main requirements for the next generation of wireless
communications systems
Adaptive Modulation and Coding with Queue Awareness in Cognitive Incremental Decode-and-Forward Relay Networks
No full textThis paper studies the performance of adaptive modulation and coding in a
cognitive incremental decode-and-forward relaying network where a secondary
source can directly communicate with a secondary destination or via an
intermediate relay. To maximize transmission efficiency, a policy which
flexibly switches between the relaying and direct transmission is proposed. In
particular, the transmission, which gives higher average transmission
efficiency, will be selected for the communication. Specifically, the direct
transmission will be chosen if its instantaneous signal-to-noise ratio (SNR) is
higher than one half of that of the relaying transmission. In this case, the
appropriate modulation and coding scheme (MCS) of the direct transmission is
selected only based on its instantaneous SNR. In the relaying transmission,
since the MCS of the transmissions from the source to the relay and from the
relay to the destination are implemented independently to each other, buffering
of packets at the relay is necessary. To avoid buffer overflow at the relay,
the MCS for the relaying transmission is selected by considering both the queue
state and the respective instantaneous SNR. Finally, a finite-state Markov
chain is modeled to analyze key performance indicators such as outage
probability and average transmission efficiency of the cognitive relay network
E-Technologies in teaching research methodology for engineers – a case study of the course for international postgraduate students
No full textThe Research Methodology course for postgraduate students is challenging, even
for an experienced academic teacher. The primary objective of this course is to
prepare participants to conduct scientific research and publish the results.
This case study presents an original teaching method applied to Research
Methodology with Emphasis on Engineering Science, for international engineering
students at Blekinge Institute of Technology in Karlskrona, Sweden. The
demanding requirements of the course, a varying number of enrolled students,
and a large number of assignments which need to be tracked and guided by the
teacher are all conditions that need a custom approach and modern tools. The
opportunities offered by e-technologies help to fulfil these course
requirements. This article shows how e-tools such Itslearning, Doodle, Zotero
or scientific database search engines, can be implemented to support the
teaching objectives. Using these tools, a single academic teacher can
accomplish the eight-week course of Research Methodology, for up to 180
students working in 60 project groups without compromising teaching quality and
students’ satisfaction. The course also has been appreciated by colleagues and
mentioned in the Master program evaluation of the Swedish Higher Education
Authority