2,802 research outputs found
Henri Temianka Correspondence; (aspen institute)
This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/3325/thumbnail.jp
Henri Temianka Correspondence; (aspen institute)
This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/1078/thumbnail.jp
Sparse Bayesian information filters for localization and mapping
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2008This thesis formulates an estimation framework for Simultaneous Localization and
Mapping (SLAM) that addresses the problem of scalability in large environments.
We describe an estimation-theoretic algorithm that achieves significant gains in computational
efficiency while maintaining consistent estimates for the vehicle pose and
the map of the environment.
We specifically address the feature-based SLAM problem in which the robot represents
the environment as a collection of landmarks. The thesis takes a Bayesian
approach whereby we maintain a joint posterior over the vehicle pose and feature
states, conditioned upon measurement data. We model the distribution as Gaussian
and parametrize the posterior in the canonical form, in terms of the information
(inverse covariance) matrix. When sparse, this representation is amenable to computationally
efficient Bayesian SLAM filtering. However, while a large majority of the
elements within the normalized information matrix are very small in magnitude, it is
fully populated nonetheless. Recent feature-based SLAM filters achieve the scalability
benefits of a sparse parametrization by explicitly pruning these weak links in an effort
to enforce sparsity. We analyze one such algorithm, the Sparse Extended Information
Filter (SEIF), which has laid much of the groundwork concerning the computational
benefits of the sparse canonical form. The thesis performs a detailed analysis of the
process by which the SEIF approximates the sparsity of the information matrix and
reveals key insights into the consequences of different sparsification strategies. We
demonstrate that the SEIF yields a sparse approximation to the posterior that is inconsistent,
suffering from exaggerated confidence estimates. This overconfidence has
detrimental effects on important aspects of the SLAM process and affects the higher
level goal of producing accurate maps for subsequent localization and path planning.
This thesis proposes an alternative scalable filter that maintains sparsity while
preserving the consistency of the distribution. We leverage insights into the natural
structure of the feature-based canonical parametrization and derive a method that
actively maintains an exactly sparse posterior. Our algorithm exploits the structure
of the parametrization to achieve gains in efficiency, with a computational cost that
scales linearly with the size of the map. Unlike similar techniques that sacrifice
consistency for improved scalability, our algorithm performs inference over a posterior
that is conservative relative to the nominal Gaussian distribution. Consequently, we
preserve the consistency of the pose and map estimates and avoid the effects of an
overconfident posterior.
We demonstrate our filter alongside the SEIF and the standard EKF both in simulation
as well as on two real-world datasets. While we maintain the computational
advantages of an exactly sparse representation, the results show convincingly that
our method yields conservative estimates for the robot pose and map that are nearly
identical to those of the original Gaussian distribution as produced by the EKF, but
at much less computational expense.
The thesis concludes with an extension of our SLAM filter to a complex underwater
environment. We describe a systems-level framework for localization and mapping
relative to a ship hull with an Autonomous Underwater Vehicle (AUV) equipped
with a forward-looking sonar. The approach utilizes our filter to fuse measurements
of vehicle attitude and motion from onboard sensors with data from sonar images of
the hull. We employ the system to perform three-dimensional, 6-DOF SLAM on a
ship hull
Developing learning materials to promote positive interaction with people with dementia: we are all in it together!
Literature on the care of people with dementia is still sparse and this is reflected in the professional education curriculum such as social work, nursing and other health care professionals (Marshall and Tibbs 2006). As life expectancy and the likelihood of dementia increases, the transition from the third to the fourth age is marked by a loss of control of the body through dementia. Its effects on the person constitutes what Gilleard and Higgs(2000) term a ‘loss of social agency’; a social death that is characterised by an exclusion from the social world and services that objectify and dehumanise the individual (Foucault 1973). Extensive research by Kitwood (1997) centred on engagement through intense interaction with individuals with dementia and promoted the concept of ‘personhood’ bringing to the forefront more person-centred and citizen approaches to dementia care (Kitwood, 1997, Marshall and Tibbs, 2006). This approach has also connected with a number of arts based methods in professional education where traditional care practices founded on more positivist stances are recognised to be limited as a basis for enquiry into the human condition.
This paper describes an educational partnership between social work and nurse educators, carers of people with dementia and an older people’s theatre project. This collaboration sought to build on cultural theories from the arts and humanities to provide a more political lens for change and reform in approaches to dementia care (Deleuze and Guttari , 1987; Barrett and Bolt 2007). Using storytelling techniques, a number of case studies were developed to inform arts based approaches such as drama and music to develop learning materials for professional and carer education. Digital images enacted by an older people’s theatre group also drew on research evidence of good practice in communication with people with dementia and a number of digital stories were developed. The paper will present some of the findings from the evaluation of the project and will illustrate this by showing some of the 3 – 4 minute clips from materials developed to facilitate further participant discussion
Personality Characteristics and Experiential Avoidance in Trichotillomania: Results from an Age and Gender Matched Sample
Despite its prevalence and a growing body of research, significant gaps remain in the knowledge of trichotillomania (TTM). The current study sought to address this issue by examining personality characteristics, impulsivity, and experiential avoidance of those with TTM compared to an age and gender matched sample. 56 Female participants (28 with TTM and 28 non-clinical age-matched controls) completed the Personality Assessment Inventory (PAI), Barratt\u27s Impulsivity Scale (BIS), and the Acceptance and Action Questionnaire (AAQ). Paired-sample t-tests compared each of the 28 individuals who met criteria for TTM to an age and gender matched individual who did not meet criteria for TTM or any Axis I condition. Significant differences were found between many of the PAI scales and subscales, impulsivity, and experiential avoidance. The TTM group displayed higher levels of pathology than the control group. The findings provide evidence that individuals with TTM demonstrate differing levels of personality characteristics compared to individuals without TTM and that treatment may benefit from acknowledging and targeting these areas
Tumour markers in breast cancer.
The clinical usefulness of 8 potential tumour markers has been evaluated in 69 patients with Stage I and II breast cancer and 57 patients with Stage III and IV. Serum CEA concentrations were raised in 13% of patients with local and 65% of those with advanced breast cancer. In patients with clinical evidence of progression or regression of tumour, serum CEA levels changed appropriately in 83% of cases. Taking 4 of the markers (carcinoembryonic antigen (CEA), lactalbumin, alpha subunit and haptoglobin) serum concentrations of one or more were raised in 33% of patients with local disease and 81% of those with advanced breast cancer. However, marker concentrations were often only marginally raised, and are unlikely to provide sensitive guide to tumour burden. CEA, lactalbumin and alpha subunit were detectable in 68%, 43% and 40% respectively of extracts of primary breast cancers
Collective motion, sensor networks, and ocean sampling
Author Posting. © IEEE, 2007. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in Proceedings of the IEEE 95 (2007): 48-74, doi:10.1109/jproc.2006.887295.This paper addresses the design of mobile sensor
networks for optimal data collection. The development is
strongly motivated by the application to adaptive ocean
sampling for an autonomous ocean observing and prediction
system. A performance metric, used to derive optimal paths for
the network of mobile sensors, defines the optimal data set as
one which minimizes error in a model estimate of the sampled
field. Feedback control laws are presented that stably coordinate
sensors on structured tracks that have been optimized
over a minimal set of parameters. Optimal, closed-loop solutions
are computed in a number of low-dimensional cases to
illustrate the methodology. Robustness of the performance to
the influence of a steady flow field on relatively slow-moving
mobile sensors is also explored
Intravesical rAd-IFNα/Syn3 for Patients With High-Grade, Bacillus Calmette-Guerin-Refractory or Relapsed Non-Muscle-Invasive Bladder Cancer: A Phase II Randomized Study.
Purpose Many patients with high-risk non-muscle-invasive bladder cancer (NMIBC) are either refractory to bacillus Calmette-Guerin (BCG) treatment or may experience disease relapse. We assessed the efficacy and safety of recombinant adenovirus interferon alfa with Syn3 (rAd-IFNα/Syn3), a replication-deficient recombinant adenovirus gene transfer vector, for patients with high-grade (HG) BCG-refractory or relapsed NMIBC. Methods In this open-label, multicenter (n = 13), parallel-arm, phase II study ( ClinicalTrials.gov identifier: NCT01687244), 43 patients with HG BCG-refractory or relapsed NMIBC received intravesical rAd-IFNα/Syn3 (randomly assigned 1:1 to 1 × 10(11) viral particles (vp)/mL or 3 × 10(11) vp/mL). Patients who responded at months 3, 6, and 9 were retreated at months 4, 7, and 10. The primary end point was 12-month HG recurrence-free survival (RFS). All patients who received at least one dose were included in efficacy and safety analyses. Results Forty patients received rAd-IFNα/Syn3 (1 × 10(11) vp/mL, n = 21; 3 × 10(11) vp/mL, n = 19) between November 5, 2012, and April 8, 2015. Fourteen patients (35.0%; 90% CI, 22.6% to 49.2%) remained free of HG recurrence 12 months after initial treatment. Comparable 12-month HG RFS was noted for both doses. Of these 14 patients, two experienced recurrence at 21 and 28 months, respectively, after treatment initiation, and one died as a result of an upper tract tumor at 17 months without a recurrence. rAd-IFNα/Syn3 was well tolerated; no grade four or five adverse events (AEs) occurred, and no patient discontinued treatment because of an adverse event. The most frequently reported drug-related AEs were micturition urgency (n = 16; 40%), dysuria (n = 16; 40%), fatigue (n = 13; 32.5%), pollakiuria (n = 11; 28%), and hematuria and nocturia (n = 10 each; 25%). Conclusion rAd-IFNα/Syn3 was well tolerated. It demonstrated promising efficacy for patients with HG NMIBC after BCG therapy who were unable or unwilling to undergo radical cystectomy
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