1,761 research outputs found
Proalgebraic crossed modules of quasirational presentations
We introduce the concept of quasirational relation modules for discrete and
pro- presentations of discrete and pro- groups and show that aspherical
presentations and their subpresentations are quasirational. In the pro--case
quasirationality of pro--groups with a single defining relation holds. For
every quasirational (pro-)relation module we construct the so called
-adic rationalization, which is a pro-fd-module
. We provide the isomorphisms
and , where and
stands for continuous prounipotent completions and corresponding
prounipotent presentations correspondingly. We show how
embeds into a sequence of abelian prounipotent
groups. This sequence arises naturally from a certain prounipotent crossed
module, the latter bring concrete examples of proalgebraic homotopy types. The
old-standing open problem of Serre, slightly corrected by Gildenhuys, in its
modern form states that pro--groups with a single defining relation are
aspherical. Our results give a positive feedback to the question of Serre.Comment: This is a corrected version of the paper which appeared in the
Extended Abstracts Spring 2015, Interactions between Representation Theory,
Algebraic Topology and Commutative Algebra, Research Perspectives CRM
Barcelona, Vol.5, 201
An Investigation into Speaker Informed DNN Front-end for LVCSR
Deep Neural Network (DNN) has become a standard method in many ASR tasks. Recently there is considerable interest in "informed training" of DNNs, where DNN input is augmented with auxiliary codes, such as i-vectors, speaker codes, speaker separation bottleneck (SSBN) features, etc. This paper compares different speaker informed DNN training methods in LVCSR task. We discuss mathematical equivalence between speaker informed DNN training and "bias adaptation" which uses speaker dependent biases, and give detailed analysis on influential factors such as dimension, discrimination and stability of auxiliary codes. The analysis is supported by experiments on a meeting recognition task using bottleneck feature based system. Results show that i-vector based adaptation is also effective in bottleneck feature based system (not just hybrid systems). However all tested methods show poor generalisation to unseen speakers. We introduce a system based on speaker classification followed by speaker adaptation of biases, which yields equivalent performance to an i-vector based system with 10.4% relative improvement over baseline on seen speakers. The new approach can serve as a fast alternative especially for short utterances
Improving generalisation to new speakers in spoken dialogue state tracking
Users with disabilities can greatly benefit from personalised voice-enabled environmental-control interfaces, but for users with speech impairments (e.g. dysarthria) poor ASR performance poses a challenge to successful dialogue. Statistical dialogue management has shown resilience against high ASR error rates, hence making it useful to improve the performance of these interfaces. However, little research was devoted to dialogue management personalisation to specific users so far. Recently, data driven discriminative models have been shown to yield the best performance in dialogue state tracking (the inference of the user goal from the dialogue history). However, due to the unique characteristics of each speaker, training a system for a new user when user specific data is not available can be challenging due to the mismatch between training and working conditions. This work investigates two methods to improve the performance with new speakers of a LSTM-based personalised state tracker: The use of speaker specific acoustic and ASRrelated features; and dropout regularisation. It is shown that in an environmental control system for dysarthric speakers, the combination of both techniques yields improvements of 3.5% absolute in state tracking accuracy. Further analysis explores the effect of using different amounts of speaker specific data to train the tracking system
Planning ahead with children with life-limiting conditions and their families : development, implementation and evaluation of ‘My Choices’
Background: The United Kingdom has led the world in the development of children’s palliative care. Over the past two decades, the illness trajectories of children with life-limiting conditions have extended with new treatments and better home-based care. Future planning is a critically under-researched aspect of children’s palliative care globally. This paper describes the development, implementation and evaluation of innovative child and parent-held palliative care planning resources. The resources were designed to facilitate parent and child thinking and engagement in future planning, and to determine care preferences and preferred locations of care for children with life-limiting conditions from diagnosis onwards. These resources fill a significant gap in palliative care planning before the end-of-life phase.
Methods: Drawing on contemporaneous research on producing evidence-based children’s health information, we collaborated with leading children’s not-for-profit organisations, parents, children, and professionals. A set of resources (My Choices booklets) were developed for parents and children and evaluated using interviews (parents, children, professionals) and questionnaires (professionals) and an open web-based consultation.
Results: Parents and children responded in three ways: Some used the booklets to produce detailed written plans with clear outcomes and ideas about how best to achieve desired outcomes. Others preferred to use the booklet to help them think about potential options. Remaining parents found it difficult to think about the future and felt there was no point because they perceived there to be no suitable local services. Professionals varied in confidence in their ability to engage with families to plan ahead and identified many challenges that prevented them from doing so. Few families shared their plans with professionals. Parents and children have far stronger preferences for home-care than professionals.
Conclusion: The My Choices booklets were revised in light of findings, have been endorsed by Together for Short Lives, and are free to download in English and Welsh for use by parents and young people globally. More work needs to be done to support families who are not yet receptive to planning ahead. Professionals would benefit from more training in person-centred approaches to future planning and additional communications skills to increase confidence and ability to engage with families to deliver sensitive palliative care planning
Using phone features to improve dialogue state tracking generalisation to unseen states
The generalisation of dialogue state tracking
to unseen dialogue states can be very
challenging. In a slot-based dialogue system,
dialogue states lie in discrete space
where distances between states cannot be
computed. Therefore, the model parameters
to track states unseen in the training
data can only be estimated from more general
statistics, under the assumption that
every dialogue state will have the same underlying
state tracking behaviour. However,
this assumption is not valid. For example,
two values, whose associated concepts
have different ASR accuracy, may
have different state tracking performance.
Therefore, if the ASR performance of the
concepts related to each value can be estimated,
such estimates can be used as general
features. The features will help to relate
unseen dialogue states to states seen
in the training data with similar ASR performance.
Furthermore, if two phonetically
similar concepts have similar ASR
performance, the features extracted from
the phonetic structure of the concepts can
be used to improve generalisation. In
this paper, ASR and phonetic structurerelated
features are used to improve the
dialogue state tracking generalisation to
unseen states of an environmental control
system developed for dysarthric speakers
Siblings of children with life-limiting conditions : psychological adjustment and sibling relationships
Background
This study explored psychological adjustment and sibling relationships of siblings of children with life-limiting conditions (LLCs), expanding on previous research by defining LLCs using a systematic classification of these conditions.
Methods
Thirty-nine siblings participated, aged 3–16 years. Parents completed measures of siblings' emotional and behavioural difficulties, quality of life, sibling relationships and impact on families and siblings. Sibling and family adjustment and relationships were compared with population norms, where available, and to a matched comparison group of siblings of children with autistic spectrum disorder (ASD), as a comparable ‘high risk’ group.
Results
LLC siblings presented significantly higher levels of emotional and behavioural difficulties, and lower quality of life than population norms. Their difficulties were at levels comparable to siblings of children with ASD. A wider impact on the family was confirmed. Family socio-economic position, time since diagnosis, employment and accessing hospice care were factors associated with better psychological adjustment.
Conclusions
Using a systematic classification of LLCs, the study supported earlier findings of increased levels of psychological difficulties in siblings of children with a LLC. The evidence is (i) highlighting the need to provide support to these siblings and their families, and (ii) that intervention approaches could be drawn from the ASD field
Paediatric palliative care : development and pilot study of a ‘Directory’ of life-limiting conditions
Background:
Children’s palliative care services are developing. Rational service development requires sound epidemiological data that are difficult to obtain owing to ambiguity in the definitions both of the population who needs palliative care and of palliative care itself. Existing definitions are of trajectory archetypes. The aim of this study was to develop and pilot a directory of the commonest specific diagnoses that map on to those archetypes.
Methods:
The diagnoses of patients under the care of five children hospices and a tertiary specialist palliative medicine service in the UK were recorded. Duplicates and diagnoses that were not life-limiting conditions according to the ACT/RCPCH criteria or were not primary were removed. The resulting Directory of life-limiting conditions was piloted by analysing Death Certificate data of children in Wales between 2002 and 2007.
Results:
1590 diagnoses from children’s hospices and 105 from specialist palliative medicine were combined. After removals there were 376 diagnostic label. All ICD10 chapter headings were represented by at least one condition. The pilot study showed that 569 (54%) deaths in Wales were caused by LLC. Only four LLC resulted in ten or more deaths. Among deaths from LLC, the ten commonest diagnoses accounted for 32%, while the 136 diagnoses that caused one or two deaths accounted for 25%. The majority occurred from a small number of life-limiting conditions.
Conclusion:
The Directory is a practical tool for identifying most life-limiting conditions using ICD10 codes that facilitates extraction and analysis of data from existing sources in respect of life-limiting conditions in children such as death certificate data, offering the potential for rapid and precise studies in paediatric palliative care
- …