223 research outputs found
Learning from Interaction: User Interface Adaptation using Reinforcement Learning
The continuous adaptation of software systems to meet the evolving needs of
users is very important for enhancing user experience (UX). User interface (UI)
adaptation, which involves adjusting the layout, navigation, and content
presentation based on user preferences and contextual conditions, plays an
important role in achieving this goal. However, suggesting the right adaptation
at the right time and in the right place remains a challenge in order to make
it valuable for the end-user. To tackle this challenge, machine learning
approaches could be used. In particular, we are using Reinforcement Learning
(RL) due to its ability to learn from interaction with the users. In this
approach, the feedback is very important and the use of physiological data
could be benefitial to obtain objective insights into how users are reacting to
the different adaptations. Thus, in this PhD thesis, we propose an RL-based UI
adaptation framework that uses physiological data. The framework aims to learn
from user interactions and make informed adaptations to improve UX. To this
end, our research aims to answer the following questions: Does the use of an
RL-based approach improve UX? How effective is RL in guiding UI adaptation? and
Can physiological data support UI adaptation for enhancing UX? The evaluation
plan involves conducting user studies to evaluate answer these questions. The
empirical evaluation will provide a strong empirical foundation for building,
evaluating, and improving the proposed adaptation framework. The expected
contributions of this research include the development of a novel framework for
intelligent Adaptive UIs, insights into the effectiveness of RL algorithms in
guiding UI adaptation, the integration of physiological data as objective
measures of UX, and empirical validation of the proposed framework's impact on
UX
Resource-efficient strategies for mobile ad-hoc networking
The ubiquity and widespread availability of wireless mobile devices with ever increasing
inter-connectivity (e. g. by means of Bluetooth, WiFi or UWB) have led to new and emerging
next generation mobile communication paradigms, such as the Mobile Ad-hoc NETworks
(MANETs). MANETs are differentiated from traditional mobile systems by their unique properties,
e. g. unpredictable nodal location, unstable topology and multi-hop packet relay. The
success of on-going research in communications involving MANETs has encouraged their applications
in areas with stringent performance requirements such as the e-healthcare, e. g. to
connect them with existing systems to deliver e-healthcare services anytime anywhere. However,
given that the capacity of mobile devices is restricted by their resource constraints (e. g.
computing power, energy supply and bandwidth), a fundamental challenge in MANETs is how
to realize the crucial performance/Quality of Service (QoS) expectations of communications in
a network of high dynamism without overusing the limited resources.
A variety of networking technologies (e. g. routing, mobility estimation and connectivity
prediction) have been developed to overcome the topological instability and unpredictability
and to enable communications in MANETs with satisfactory performance or QoS. However,
these technologies often feature a high consumption of power and/or bandwidth, which makes
them unsuitable for resource constrained handheld or embedded mobile devices. In particular,
existing strategies of routing and mobility characterization are shown to achieve fairly
good performance but at the expense of excessive traffic overhead or energy consumption. For
instance, existing hybrid routing protocols in dense MANETs are based in two-dimensional organizations
that produce heavy proactive traffic. In sparse MANETs, existing packet delivery
strategy often replicates too many copies of a packet for a QoS target. In addition, existing
tools for measuring nodal mobility are based on either the GPS or GPS-free positioning systems,
which incur intensive communications/computations that are costly for battery-powered
terminals. There is a need to develop economical networking strategies (in terms of resource
utilization) in delivering the desired performance/soft QoS targets.
The main goal of this project is to develop new networking strategies (in particular, for
routing and mobility characterization) that are efficient in terms of resource consumptions while
being effective in realizing performance expectations for communication services (e. g. in the
scenario of e-healthcare emergency) with critical QoS requirements in resource-constrained
MANETs.
The main contributions of the thesis are threefold:
(1) In order to tackle the inefficient bandwidth utilization of hybrid service/routing discovery
in dense MANETs, a novel "track-based" scheme is developed. The scheme deploys
a one-dimensional track-like structure for hybrid routing and service discovery. In comparison
with existing hybrid routing/service discovery protocols that are based on two-dimensional
structures, the track-based scheme is more efficient in terms of traffic overhead (e. g. about 60%
less in low mobility scenarios as shown in Fig. 3.4). Due to the way "provocative tracks" are
established, the scheme has also the capability to adapt to the network traffic and mobility for
a better performance.
(2) To minimize the resource utilization of packet delivery in sparse MANETs where wireless
links are intermittently connected, a store-and-forward based scheme, "adaptive multicopy
routing", was developed for packet delivery in sparse mobile ad-hoc networks. Instead
of relying on the source to control the delivery overhead as in the conventional multi-copy
protocols, the scheme allows each intermediate node to independently decide whether to forward
a packet according to the soft QoS target and local network conditions. Therefore, the
scheme can adapt to varying networking situations that cannot be anticipated in conventional
source-defined strategies and deliver packets for a specific QoS targets using minimum traffic
overhead.
ii
(3) The important issue of mobility measurement that imposes heavy communication/computation
burdens on a mobile is addressed with a set of resource-efficient "GPS-free" soluti ons,
which provide mobility characterization with minimal resource utilization for ranging and signalling
by making use of the information of the time-varying ranges between neighbouring
mobile nodes (or groups of mobile nodes). The range-based solutions for mobility characterization
consist of a new mobility metric for network-wide performance measurement, two
velocity estimators for approximating the inter-node relative speeds, and a new scheme for
characterizing the nodal mobility. The new metric and its variants are capable of capturing the
mobility of a network as well as predicting the performance. The velocity estimators are used to
measure the speed and orientation of a mobile relative to its neighbours, given the presence of a
departing node. Based on the velocity estimators, the new scheme for mobility characterization
is capable of characterizing the mobility of a node that are associated with topological stability,
i. e. the node's speeds, orientations relative to its neighbouring nodes and its past epoch time.
iiiBIOPATTERN EU Network of Excellence (EU Contract 508803
A Contextual Framework for Adaptive User Interfaces: Modelling the Interaction Environment
The interaction context (or environment) is key to any HCI task and
especially to adaptive user interfaces (AUIs), since it represents the
conditions under which users interact with computers. Unfortunately, there are
currently no formal representations to model said interaction context. In order
to address this gap, we propose a contextual framework for AUIs and illustrate
a practical applica- tion using learning management systems as a case study. We
also discuss limitations of our framework and offer discussion points about the
realisation of truly context-aware AUIs.Comment: 5 pages, 2 figure
Third international workshop on Authoring of adaptive and adaptable educational hypermedia (A3EH), Amsterdam, 18-22 July, 2005
The A3EH follows a successful series of workshops on Adaptive and Adaptable Educational Hypermedia. This workshop focuses on models, design and authoring of AEH, on assessment of AEH, conversion between AEH and evaluation of AEH. The workshop has paper presentations, poster session and panel discussions
Adaptivity as a key feature of mobile maps in the digital era
Mobile maps are an important tool for mastering modern digital life. In this paper, we outline our perspective on the challenges and opportunities associated with designing adaptive mobile maps that are useful, usable, and accessible to a wide range of users in different contexts. If we claim for adaptive mobile maps to be successful, we need to expand our understanding of map use context, including the physical and digital spaces, user behavior, and individual differences. We identify key challenges, such as the scarcity of knowledge about mobile map use behavior, the need for effective adaptation methods and strategies, user acceptance of adaptive maps, and issues related to control, privacy, trust, and transparency. We finally suggest research opportunities, such as studying mobile map usage, employing AI-based adaptation methods, leveraging the power of visual communication through maps, and ensuring user acceptance through user control and privacy
Magnetic Resonance Imaging of the Neonatal Cardiovascular System : Impact of Patent Ductus Arteriosus
The incidence of premature birth is increasing in absolute number and as a proportion of all births
around the world. Many pathologies seen in this cohort are related to abnormal blood supply. Fetal
and premature cardiovascular systems differ greatly as to maintain adequate blood flow to the
developing organs in the uterine and extra-uterine environments require very different circulations.
Subsequently following preterm birth the immature cardiovascular system undergoes abrupt
adaptations, often resulting in the prolonged patency of the fetal shunt, ductus arteriosus. The
impact of a patent ductus arteriosus (PDA) is poorly understood. However it is thought that large
ductal shunt volumes may result in congestive cardiac failure and systemic hypo-‐perfusion.
Cardiac MRI has contributed greatly to the understanding of many cardiovascular diseases and
congenital defects in paediatric and adult patients. Translating these imaging techniques to assess
the preterm cardiovascular system requires careful optimization due to their condition, size and
significantly increased heart rate. The work presented in this thesis employs multiple functional CMR
techniques to investigate the preterm cardiovascular system in the presence and absence of PDA
and the resultant cardiac function.
A novel technique utilizing PC MRI to quantify PDA shunt volume and its impact on flow distribution
is presented. Despite large shunt volumes, systemic circulation remained within normal range,
although slight reduction is detectable when assessed at group level. Subsequently the impact of
PDA and associated increased work load on left ventricular dimensions and function was then
investigated using SSFP imaging. Results indicated that cardiac function was maintained even in the
presence of large shunt volumes. Finally 4D PC sequences were employed to evaluate pulse wave
velocity and flow regime within the preterm aorta, demonstrating the feasibility of hemodynamic
assessment in this cohort. The findings of these studies provide insight into the impact of PDA. The
reliable measurement and assessment of preterm cardiovascular system provides the potential to
improve the understanding of the development and effects of certain pathologies seen in this
cohort.Open Acces
In-Vitro and In-Silico Investigations of Alternative Surgical Techniques for Single Ventricular Disease
Single ventricle (SV) anomalies account for one-fourth of all cases of congenital Heart disease. The conventional second and third stage i.e. Comprehensive stage II and Fontan procedure of the existing three-staged surgical approach serving as a palliative treatment for this anomaly, entails multiple complications and achieves a survival rate of 50%. Hence, to reduce the morbidity and mortality rate associated with the second and third stages of the existing palliative procedure, the novel alternative techniques called “Hybrid Comprehensive Stage II” (HCSII), and a “Self-powered Fontan circulation” have been proposed. The goal of this research is to conduct in-vitro investigations to validate computational and clinical findings on these proposed novel surgical techniques. The research involves the development of a benchtop study of HCSII and self-powered Fontan circulation
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