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Action research as a model for industry-academia collaboration in the software engineering context
No full textBackground: Action research is a well-established research methodology. It is
following a post-positivist research philosophy grounded in critical thinking.
The methodology is driven by practical problems, emphasis participatory
research, and develops practically useful solutions in an iterative manner.
Objective: Two objectives are to be achieved: (1) Understanding the state of
the art with respect to action research usage in the software engineering
literature, and (2) reflecting and providing recommendations of how to foster
industry-academia collaboration through action research.
Method:} Based on our experience with two action research studies in close
collaboration with Ericsson lessons learned and guidelines are presented.
Results: In both cases presented action research led to multiple refinements in
the interventions implemented. Furthermore, the close collaboration and
co-production with the industry was essential to identify and describe the
required refinements to provide an in-depth understanding. In comparison with
previous studies, we required multiple iterations while previous software
engineering studies reported mostly one iteration, or were not explicit
regarding the number of iterations studied.
Conclusion: We conclude that action research is a powerful tool for
industry-academia collaboration. The success of the method highly depends on
the researchers and practitioners working in a team. Future studies need to
improve the reporting with respect to describing the type of action research
used, the iterations, the model of collaboration, and the rationales for
changes in each iteration
Comparative Performance Study of LTE Downlink Schedulers
No full textLong time evolution (LTE) represents an emerging and promising technology for
providing broadband, mobile Internet access. Because of the limitation of
available spectrum resource, high spectrum efficiency technologies such as
channel-aware scheduling need to be explored. In this work, we evaluate the
performance of three scheduling algorithms proposed for LTE downlink
transmission. The evaluation takes place in mixed traffic scenarios and aims at
exploring strengths and weaknesses of the proposed algorithms. Simulation
results illustrate the importance of real-time traffic awareness by schedulers
when a specified level of quality of service is required. The research shows
that lack of prioritisation of multimedia traffic will lead to severe
degradation of video and VoIP services even with a relatively low network load
Wireless Information and Power Transfer in an Underlay Cognitive Radio Network
No full textIn this paper, we consider a secondary network with simultaneous wireless
information and power transfer in a
spectrum sharing scenario. In particular, a secondary user (SU) transmitter
communicates with multiple SU receivers (SU-Rxs) under the peak interference
power constraint of the primary user receiver and the SU maximum transmit power
limit. We apply a channel quality-based threshold and exploit opportunistic
scheduling. Specifically, an SU-Rx with best channel condition among a set of
SU-Rxs satisfying the threshold is scheduled for data transmission. The
remaining SU-Rxs with channel condition below the threshold, harvest the radio
frequency energy. Analytical expressions of the SU ergodic capacity, symbol
error rate, throughput, and energy harvesting are obtained. An optimal
threshold satisfying a given target outage probability is determined. Numerical
results are provided to investigate the impact of different parameters on the
secondary network performance
Achievable Secrecy Capacity in an Underlay Cognitive Radio Network
No full textIn this paper, we consider a spectrum sharing cognitive radio network where a
secondary user (SU) transmitter (SU-Tx) communicates with multiple SU receivers
(SU-Rxs). There exist multiple eavesdroppers (EAVs) who illegally listen to the
secondary network communication. Further, the primary network consists of a
primary user (PU) transmitter serving multiple PU receivers. In particular, the
SU-Tx transmit power is subject to the joint constraint of PU outage and SU
maximum transmit power limit. Moreover, we investigate the secondary network
physical layer security in terms of average secrecy capacity for both cases of
known and unknown channel information of the EAV at the SU-Tx. Numerical
results are provided to evaluate the impact of the number of PU-Rxs, number of
EAVs, number of SU-Rxs, and channel mean powers among users on the SU average
secrecy capacity
Advancements in package opening simulations
No full textThe fracture mechanical phenomenon occurring during the opening of a beverage
package is rather complex to simulate. Reliable and calibrated numerical
material models describing thin layers of packaging materials are needed.
Selection of appropriate constitutive models for the continuum material models
and how to address the progressive damage modeling in various loading scenarios
is also of great importance. The inverse modeling technique combined with video
recording of the involved deformation mechanisms is utilized for identification
of the material parameters. Large deformation, anisotropic non-linear material
behavior, adhesion and fracture mechanics are all identified effects that are
needed to be included in the virtual opening
model.
The results presented in this paper shows that it is possible to select
material models in conjunction with continuum material
damage models, adequately predicting the mechanical behavior of failure in thin
laminated packaging materials. Already available techniques and functionalities
in the commercial finite element software Abaqus are used. Furthermore,
accurate descriptions of the included geometrical features are important.
Advancements have therefore also been made within the experimental techniques
utilizing a combination of microCT-scan, SEM and photoelasticity enabling
extraction of geometries and
additional information from ordinary experimental tests and broken specimens.
Finally, comparison of the experimental opening and the virtual opening, showed
a good correlation with the developed finite element modeling technique
On User Perception of Authentication in Networks
No full textAuthentication solutions are designed to stop unauthorized users from getting
access to a secured system. However, each time an authentication process occur
an authorized user needs to wait in expectation of approved access. This effort
can be perceived as either a positive or negative experience. If the effort is
perceived as a security measure; the effort is usually perceived as a positive
experience. On the other hand, if the effort is perceived as a waiting time;
the effort is usually perceived as a negative experience. The trade-off between
security, user-friendliness and simplicity plays an important role in the
domain of user acceptability. From the users' point of view, security is both
necessary and disturbing at the same time.
The overall focus in this thesis is on user perception of authentication in
communication networks. An authentication procedure, or login, normally
includes several steps and messages between a client and a server. In addition,
the connection could suffer from low Quality of Service, i.e., each step in the
authentication process will add to a longer response time. The longer response
times will then infer lower Quality of Experience, i.e., a worse user
perception.
The thesis first presents a concept of investigating user perception. A
framework is developed in which different criteria and evaluation methods for
authentication schemes are presented. This framework is then used to
investigate user perception of the response times of a web authentication
procedure. The derived result, which is an exponential function, is compared to
models for user perception of web performance. The comparison indicates that
users perceive logins similarly, but not identically, to how they perceive
standard web page loading.
The user perception, with regards to excessive authentication times, is further
studied by determining the weak point of the Extensible Authentication Protocol
Method for GSM Subscriber Identity Modules (EAPSIM) with the OpenID service.
The response times are controllably increased by emulating bad network
performance for EAP-SIM and other EAP methods in live setups. The obtained
results show that one task of the EAP-SIM authentication deviates from the
other tasks, and contributes more to the total response time. This deviation
points out the direction for future optimization.
Finally, this thesis investigates how users of social networks perceive
security, and to which extent they contribute to it. One way of contributing to
security by creating and using strong authentication credentials, e.g.
passwords. Websites might enforce a password length which is insufficient to
provide a strong password. This might then cause problems by giving users a
false perception of what constitutes a strong password. The origin of the
password problem, namely the construction of passwords, and the user perception
of password security is studied. A survey is conducted and the results indicate
that the passwords of the respondents are not as strong as the respondents
perceive them to be
In press: Improved concept drift handling in surgery prediction and other applications
No full textThe article presents a new algorithm for handling concept drift: the
Trigger-based Ensemble (TBE) is designed to handle concept drift in surgery
prediction but it is shown to perform well for other classification problems as
well. At the primary care, queries about the need for surgical treatment are
referred to a surgeon specialist. At the secondary care, referrals are reviewed
by a team of specialists. The possible outcomes of this review are that the
referral: (i) is canceled, (ii) needs to be complemented, or (iii) is predicted
to lead to surgery. In the third case, the referred patient is scheduled for an
appointment with a surgeon specialist. This article focuses on the binary
prediction of case three (surgery prediction). The guidelines for the referral
and the review of the referral are changed due to, e.g., scientific
developments and clinical practices. Existing decision support is based on the
expert systems approach, which usually requires manual updates when changes in
clinical practice occur. In order to automatically revise decision rules, the
occurrence of concept drift (CD) must be detected and handled. The existing CD
handling techniques are often specialized; it is challenging to develop a more
generic technique that performs well regardless of CD type. Experiments are
conducted to measure the impact of CD on prediction performance and to reduce
CD impact. The experiments evaluate and compare TBE to three existing CD
handling methods (AWE, Active Classifier, and Learn++) on one real-world
dataset and one artificial dataset. TBA significantly outperforms the other
algorithms on both datasets but is less accurate on noisy synthetic variations
of the real-world dataset
Prediction of faults-slip-through in large software projects: an empirical evaluation
No full textA large percentage of the cost of rework can be avoided by finding more faults
earlier in a software test process. Therefore, determination of which software
test phases to focus improvement work on has considerable industrial interest.
We evaluate a number of prediction techniques for predicting the number of
faults slipping through to unit, function, integration, and system test phases
of a large industrial project. The objective is to quantify improvement
potential in different test phases by striving toward finding the faults in the
right phase. The results show that a range of techniques are found to be useful
in predicting the number of faults slipping through to the four test phases;
however, the group of search-based techniques (genetic programming, gene
expression programming, artificial immune recognition system, and particle
swarm optimization-based artificial neural network) consistently give better
predictions, having a representation at all of the test phases. Human
predictions are consistently better at two of the four test phases. We conclude
that the human predictions regarding the number of faults slipping through to
various test phases can be well supported by the use of search-based
techniques. A combination of human and an automated search mechanism (such as
any of the search-based techniques) has the potential to provide improved
prediction results
Integrating a Strategic Sustainability Perspective into Eco-Labelling, Procurement and Supply Chain Management
No full textMaintaining the current course of the global society is threatening the human
civilization. The urgency of the situation, understood from empirical research,
has caused many researchers to call for more prescriptive research as a
necessary supplement, to better support decision making for sustainability.
While policymakers need to direct and stimulate sustainable production and
consumption through, e.g., legislation and market phenomena such as
eco-labelling, business represents a significant proportion of the necessary
resources, capabilities and mechanisms for the innovation needed for a
transition towards sustainability. However, while businesses more and more
realize the self-interest in working proactively with sustainability, there is
a desire for better support for how to do this also from this end. Such support
needs to consider a significant shift going on in business; that individual
businesses tend to no longer compete as autonomous entities, but rather as
supply chains. Thus, no company is more sustainable than its supply chain
partners. Therefore, sustainable supply chain management (SSCM) as a business
function, and sustainable procurement as a subset thereof, plays an
increasingly pivotal role for sustainable development.
The overall aim of this thesis is to contribute to sustainable development by
studying how three phenomena; eco-labelling, procurement and supply chain
management are related to each other and to a strategic sustainability
perspective, and to suggest how these phenomena can be integrated with such a
perspective to provide better support for decision making and innovation for
sustainability. For this purpose, a framework for strategic sustainable
development, including a definition of sustainability and generic guidelines to
inform stepwise strategic plans towards sustainability, is used as a
foundational methodology. The development of new approaches is also based on
case studies with eco-labelling and sustainable public procurement bodies,
businesses and public institutions. Information is collected by shadowing of
criteria development and collaboration processes, interviews and literature
studies.
While the findings point to a clear rational for all of the phenomena and
several strengths in existing schemes and practices, the findings also point to
several shortcomings. Sustainability is not defined, and as a result, there is
no foundation for strategic and proactive approaches. Furthermore, decisions
are not based on considerations of all dimensions of sustainability, the whole
life cycle of products, all relevant stakeholders and a long-term perspective.
As a result, the full potential of these phenomena for contributing to
sustainable development is not utilized.
This thesis prescribes enhanced processes for eco-labelling, sustainable
procurement and SSCM, and shows how these can support organisations in
developing from reacting individually on known sustainability-related problems
to acting proactively and collaboratively in supply chains, in a coordinated
and economically viable way, on society’s remaining gap to the full scope of
ecological and social sustainability
