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Low-Complexity Algorithms for Echo Cancellation in Audio Conferencing Systems
No full textEver since the birth of the telephony system, the problem with echoes, arising
from impedance mismatch in 2/4-wire hybrids, or acoustic echoes where a
loudspeaker signal is picked up by a closely located microphone, has been ever
present. The removal of these echoes is crucial in order to achieve an
acceptable audio quality for conversation. Today, the perhaps most common way
for echo removal is through cancellation, where an adaptive filter is used to
produce an estimated replica of the echo which is then subtracted from the
echo-infested signal.
Echo cancellation in practice requires extensive control of the filter
adaptation process in order to obtain as rapid convergence as possible while
also achieving robustness towards disturbances. Moreover, despite the rapid
advancement in the computational capabilities of modern digital signal
processors there is a constant demand for low-complexity solutions that can be
implemented using low power and low cost hardware.
This thesis presents low-complexity solutions for echo cancellation related to
both the actual filter adaptation process itself as well as for controlling the
adaptation process in order to obtain a robust system. Extensive simulations
and evaluations using real world recorded signals are used to demonstrate the
performance of the proposed solutions
Geographical Information Technologies – Decision Support for Road Maintenance in Uganda
No full textThis study set out to develop a framework within which the use of Geographical
Information Technologies (GITs) can be enhanced in Road Infrastructure
Maintenance (RIM) in Uganda. Specifically it was guided by 3 objectives; 1. To
assess the gaps in the use of GITs for RIM in Uganda and the limitations to
accessing these technologies, 2. To develop a methodological framework to
enhance the use of GITs in RIM and 3. To develop a Geographical Information
Systems for Transportation (GIS-T) data model based on the road maintenance
data requirements. A participatory approach through a series of interviews,
focus group discussions, workshop & conferences, document reviews, field
observations & measurements and GIS analysis were employed.
Based on the Spatial Data Infrastructure (SDI) concept and the principle of
Causality, the gaps and limitations were established to mainly be concerned
with data and organisational constraints as opposed to technical issues. They
were classified to include; inadequate involvement of GITs in organisational
activities, inappropriate institutional arrangements, absence of data sharing
frameworks, budget constraints, insufficient geospatial capacity, digital
divide in the perception, adoption & affordability of GITs among the
stakeholders and the absence of a road maintenance Spatial Data Infrastructure
(SDI).
A methodological framework, comprising of 6 strategic components was developed
to enhance the use of GITs in RIM. This included enactment of relevant policy
components to guide GIT use, continuous capacity building, establishment of a
road maintenance SDI, fostering collaboration and spatial data sharing
frameworks, budgetary allocation based on defined activities inclusive of GIT
initiatives, and adoption of a dynamic segmentation data model.
Conceptual and logical data models were developed and proposed for the Sector.
The conceptual model, presented using an entity relationship diagram, relates
the road network to the point and line events occurring on it. The logical
object relational model developed using the ESRI provided template represents
the road and the point and line events in a total of 19 object classes.
The Study concludes that in order to ground GIT benefits in the sector;
technical, data and organisational concerns involved in GIT undertakings should
be accorded equal emphasis. Institutionalisation and diffusion of GITs as
aspects of the component strategies are regarded capacity building mechanisms
earmarked to boost success in GIT initiatives. Further research on diffusion
and funding models for GIT initiatives is recommended. It is suggested that
aspects of the proposed model be considered when establishing GIT standards for
the sector. The RIM sector is encouraged to embrace Science and Technology and
to participate in Research and Development and particularly to adopt the
culture of innovation considering the ready availability of off the shelf
equipment, freeware and open source software that can foster informed decision
making
Demonstrating the Stalling Events with Instantaneous Total Power Consumption in Smartphone-based Live Video Streaming
No full textThe smartphone usage nearly tripled 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 streaming session, due to
varying conditions on network and application levels. Recent studies focus on
the averaged power consumption statistics, while there is lack of observation
on the fluctuations of the instantaneous total power consumption of the smart-
phones. Network based applications consume power at all layers of the
communication stack, and any fluctuation in the total power consumption during
a video streaming can reveal a possible misbehaviour such as a stalling event.
Until now, these events are investigated in Quality of Experience (QoE) studies
through installation of high-energy demanding and hard-to-deploy network
measurement tools on users’ mobile devices. In this paper, we demonstrate an
ex- periment, where a user experiences a stalling event on the smartphone and
observes the live instantaneous power consumption values through Mobile Power
Monitoring Tool (MPMT) and Software Visualisa- tion Tool (SVT), simultaneously.
We confer that the instantaneous total power consumption likely reveals the
misbehaviours such as stalls during a video play- out in live video streaming
on smartphones that can facilitate energy efficient QoE studies
Simulations of the VISIR Open Lab Platform
No full textThis paper presents a queue simulation of the VISIR Open Lab Platform. A model
of the platform 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 concurrent students that can be allowed to use the
platform while at the same time keeping a low response time to ensure the
quality of the service. The results show, in a worst case setup with
approximately 300 ms response time per experiment, that roughly 100 concurrent
users is an upper limit to ensure an average response time below 2 s. The
results also show that raising the limit of the desired experiment response
time does not necessarily increase the number allowed concurrent users
significantly once the system is saturated. However, improving the experiment
response time can significantly increase the number of users that can
simultaneously be connected
Pedagogik, undervisning och lärande
No full textDen här är en bok som handlar om pedagogik och lärande. Den handlar också om
etik, demokrati och civilkurage. Boken innehåller konkreta exempel som bygger
på författarens livslånga lärargärning. Varje kapitel bidrar till ett
provokativt utforskande av arbets-, lärande- och livsvillkoren för undervisare
såväl som för andra människor. Bokens centrala frågeställning utgår från en
klassisk problematik kring arbete, lärande och utveckling: På vilket sätt
uppstår förutsättningar för lärande, hur hanterar människan sin
kunskapsutveckling och vilka är de produktiva miljöerna på nätet, arbetet och
skolan
Towards Value Driven Simulation of Product-Service Systems - A Conceptual Scenario
No full textThe paper discussed potentials and existing challenges of considering Value
when designing a Product-Service System offering. The main problem has been
identified on having new methods and tools that can help designers to consider
every design option from a value perspective (possibly based on a longer
timespan). Nowadays mainly revenue, costs and technical risks analysis are
taken into consideration and boiled down into monetary terms in a rather short
period. This often caused the “killing” of more radical ideas (that could
potentially bring more benefits if seen in a longer time perspective) at the
various decision gates during the project. So at the end, everybody talks about
value, but actually money is what people look at in the end. The paper
discussed how a Value simulation approach can provide benefits in terms of
compared different design solutions from a Value perspective. With such an
approach it is possible to take into consideration the value of aspects like
intangibles perceived by the customer (provide the best customer experience as
possible) or knowledge gained by the company during the business. An example
has been presented in order to discuss how Value simulation can be effectively
a strength when dealing with the wider design space that the PSS development
implies. Another main benefit is that such a tool will enable engineers to have
at least “reasoning” in order to sponsor more radical concepts. Thirdly, the
tool can enable optimization and increase innovation, since the team can look
at why the model has low value in a certain lever, and starting to brainstorm
possible solutions of how to increase it. However, the approach is still in its
infancy and future work needs to be done. First of all, the weighting phase is
crucial since it will profoundly affect the model. Further research will focus
how the design team can place define weights in a qualitative but effective
way, in order to take the major benefits from a “lightweight” qualitative
approach and the simulation based on mathematical equations. Secondly, work has
to address how intangibles and knowledge can affect monetary parameters, such
as the price of the offerings or costs (making the intangibles tangible, so to
say). This will require further research, but it has been seen as a great
opportunity of making a step further in the topic, since the uncovered areas
realted intangibles and knowledge are still many
The n-dimensional Stern-Brocot tree
No full textThe n-dimensional Stern-Brocot tree consists of all sequences (p₁, ...,p_{n})
of positive integers with no common multiple. The relatively prime sequences
can be generated branchwise from each other by simple vector summation,
starting with an ON-base, and controlled by a generalized Euclidean
algorithm.The tree induces a multiresolution partition of the first quadrant of
the (n-1)-dimensional unit sphere, providing a direction approximation property
of a sequence by its ancestors. Two matrix representations are introduced,
where in both a matrix contains the parents of a sequence. From one of them the
isomorphism of a subtree to the entire tree of dimension equal to the number of
parents of the top sequence follows.
A form of Fibonacci sequences turn out to be the sequences of fastest growing
sums. The construction can be regarded an n-dimensional continued fraction, and
it may invite further n-dimesional number theory
On Decision Support in Participatory Medicine Supporting Health Care Empowerment
No full textThe task of ensuring Patient Safety is, more than ever, central in Healthcare.
The report “To Err is Human” [Kohn et al. 2000], was revealing alarming numbers
of incidents, injuries and deaths caused by deficiencies in healthcare
activities. The book initiated assessment and change of Healthcare methods and
procedures. In addition, numerous reports to Swedish HSAN (Medical
Responsibility Board) have shown a high rate of information and communication
deficiencies in Healthcare has a direct or indirect cause of incidents,
injuries and deaths. Despite numerous of new sophisticated tools for
information management in recent years, e.g., tools such as Electronic Health
Records (EHR) and Clinical Decision Support Systems (CDSS), the threats to
Patient Safety have not been redeemed. Rather to the contrary. Underlying
reasons for this paradox are twofold. Firstly, advancements in diagnosing
techniques have given rise to increasing volumes of data at the same time as
the number of patients has increased due to demographic changes and
advancements in treatments. Secondly, the information processing systems are
far from aligned to related workflow processes. In short, we do not at present
have interoperability in our Healthcare systems.
In this doctoral dissertation, we present an in-depth analysis of two different
“HSAN-typical” cases, where Patient Safety was jeopardized by incomplete
information flows and/or information breakdowns. The cases are mirroring the
apprehension of Simplicity, that is, Occam´s Razor of Diagnostic Parsimony. A
well-known protocol used in Healthcare and implemented in most (knowledge
based) CDSS. This rule of thumb is the foundation for the well-known adage:
“when you hear hoof beats, think horses, not zebras”. Hickam´s Dictum is one
well known objection to the simplifications of Occam´s Razor stating "Patients
can have as many diseases as they damn well please". Of course, this Dictum is
harder to implement effectively! In the thesis we suggest a visualization tool
Visual Incidence Anamneses (VIA) to provide middle out compromise between
Ockham and Hickam but providing means to increase Patient Safety.
The findings of our Study for the thesis have resulted in a number of Aspects
and Principles as well as Core-principles for future CDSS design, That is,
tools and methodologies that will support designing and validating
Interoperability of Healthcare systems across patient-centric workflows. The
VIA tool should be used as the initiating point in a patient (individual)
centered workflow, quickly visualizing vital information such as symptoms,
incidents and diagnoses, occurring earlier in the medical history, at different
times, to ground further vital decisions on. The visualization will enable
analysis of timelines and earlier diagnoses of the patient, using visually
salient nodes for visualization of causalities in context. Furthermore, support
for customization of the tool to the views of stakeholders, members of
healthcare teams and empowerments of the patient, is crucial
Self and next of kin’s assessment of personality and sense of coherence in elderly people: Implications for dementia care
No full textNurses sometimes fail to understand the behaviour of individuals with severe
dementia. Information from a next of kin may help to bridge this communicative
gap. One factor that influences a person’s reaction to a disease is their
personality and ability to cope with stress. The aim of this study was to
evaluate the inter-rater agreement between healthy elderly people’s
self-assessment and the assessment made by a next of kin concerning personality
and sense of coherence. The participants (n¼154) answered questions from the
Eysenck Personality
Inventory (EPI) and the Antonovsky Sense of Coherence (SOC) scale. The study
shows high or moderate agreement in ratings when analysed by means of an
intra-class correlation coefficient (range between r¼.57 and r¼.72) and the
results indicate that in general a close relative is able to
report on the personality of a next of kin. The inter-rater agreement was high
on SOC and extraversion and somewhat lower on neuroticism. For neuroticism,
length of time in the relationship increased the odds for a good inter-rater
agreement. Thus, seemingly a next of kin is a reliable informant for the
elderly in general and is probably also able to add information useful in the
nursing care of people with dementia
"Småprat" är inget hälsosamtal - En modell för att implementera hälsosamtal med stöd i motiverande samtal
No full textBakgrund: Kravet om att hälso- och sjukvården skall arbeta hälsofrämjande
beskrivs i åtskilliga policy- och styrdokument. Trots detta visar forskning att
det hälsofrämjande arbetet är föga genomslaget i den kliniska verksamheten.
Forskning visar också att patienter önskar samtal om sina levnadsvanor i mötet
med hälso- och sjukvårdspersonal. Följaktligen förväntas personal inom Hälso-
och sjukvården bedriva någon form av samtal om hälsa. Primärvården har haft
problem med att leva upp till åtagandet om hälsofrämjande insatser. Resurser,
kompetens och mandat för det hälsofrämjande arbetet har brustit men framför
allt har det saknats strategier för hur insatserna skall implementeras.
Syfte: Syftet med studien var att identifiera förutsättningar och hinder i den
lokala kontexten för implementering av hälsosamtal med stöd i motiverande
samtal (MI) och utifrån dessa utveckla en strategi som kan utgöra en grund för
implementering.
Metod: Fyra fokusgruppintervjuer genomfördes med personal vid en vårdcentral
som är ålagda att genomföra hälsosamtal. Intervjuerna transkriberades och
analyserades med en kvalitativ innehållsanalys.
Resultat: Analysen visade såväl förutsättningar som hinder i
implementeringsprocessen av hälsosamtal med stöd i motiverande samtal. Två
teman med dess tillhörande kategorier och underkategorier kunde urskiljas. Det
ena temat fokuserade på att skapa förutsättningar och undanröja hinder inför
implementering av hälsosamtal och det andra på temat på att skapa
förutsättningar och undanröja hinder i genomförandet av hälsosamtal.
Diskussion: Analysen visade att tiden utgör ett hinder för att bedriva samtal
med stöd i motiverande samtal. Forskning påvisar dock att det inte krävs mer
tid i mötet med patienten för att tillämpa MI. Förmodligen förutsätts det då
att personalen känner sig bekväm och har vana av att arbeta med MI för att
kunna uppleva metoden som mindre tidskrävande. Utbildning i MI och med träning
i tillämpning kan då tolkas vara en förutsättning för en hållbar
implementering, vilket också denna studie visar. Organisationsklimatet som
bland annat utgörs av relationer, värderingar och samarbete inom organisationen
är också påverkar implementeringsprocessen. Föreliggande resultat påvisar att
det finns en del otydligheter avseende organisationsklimatet som bör beaktas i
implementeringen av MI.
Slutsats: För att lyckas med implementering av hälsosamtal med stöd i MI och
därmed kunna erbjuda patienter hälsosamtal som utgår från evidensbaserad
kunskap, är det väsentligt att följa en strategi som utgår från befintligt
kunskapsunderlag och är förankrad i den lokala kontexten