1,587 research outputs found
Partitioning intensity inhomogeneity colour images via Saliency-based active contour
Partitioning or segmenting intensity inhomogeneity colour images is a challenging problem in computer vision and image shape analysis. Given an input image, the active contour model (ACM) which is formulated in variational framework is regularly used to partition objects in the image. A selective type of variational ACM approach is better than a global approach for segmenting specific target objects, which is useful for applications such as tumor segmentation or tissue classification in medical imaging. However, the existing selective ACMs yield unsatisfactory outcomes when performing the segmentation for colour (vector-valued) with intensity variations. Therefore, our new approach incorporates both local image fitting and saliency maps into a new variational selective ACM to tackle the problem. The euler-lagrange (EL) equations were presented to solve the proposed model. Thirty combinations of synthetic and medical images were tested. The visual observation and quantitative results show that the proposed model outshines the other existing models by average, with the accuracy of 2.23% more than the compared model and the Dice and Jaccard coefficients which were around 12.78% and 19.53% higher, respectively, than the compared model
Using neurobiological measures to predict and assess trauma-focused psychotherapy outcome in youth with posttraumatic stress disorder
In this thesis we examined different predictive neurobiological measures of traumafocused psychotherapy response and investigated the biological mechanisms underlying trauma-focused psychotherapy response in youth with PTSD. Our results suggest that activity of the major neuroendocrine stress response systems and brain functional connectivity before treatment are indeed associated with trauma-focused treatment response. Moreover, trauma-focused psychotherapy response seems to be related to longitudinal changes in autonomic nervous system activity during stress and brain structure. Together, these findings improve our understanding of the relationship between neurobiological measures and traumafocused psychotherapy response in youth with PTSD. However, these insights have currently limited to no clinical value because the current state of evidence does not support implementation of neurobiological biomarkers for treatment selection and necessary trials of (augmentation) treatments targeting neurobiological mechanisms related to treatment response have not been performed yet. The way forward now, is to perform individual prediction studies in less heterogeneous patient samples and to perform developmentally informed long-term studies examining (neuro) developmental trajectories related to PTSD and treatment response. These studies are necessary to address whether neurobiological measures can eventually improve treatment outcome and reduce the burden of PTSD in affected youth
Approximation of functions with possibly infinite jump set
We prove an approximation result for functions
such that is -integrable, , and is
integrable over the jump set (whose measure is possibly
infinite), for some continuous, nondecreasing, subadditive function , with
. The approximating functions are piecewise affine
with piecewise affine jump set; the convergence is that of for and
the convergence in energy for and for
suitable functions . In particular, converges to -strictly,
area-strictly, and strongly in after composition with a bilipschitz map.
If in addition , we also have convergence of
to
Segment Anything Model (SAM) for Radiation Oncology
In this study, we evaluate the performance of the Segment Anything Model
(SAM) model in clinical radiotherapy. We collected real clinical cases from
four regions at the Mayo Clinic: prostate, lung, gastrointestinal, and head \&
neck, which are typical treatment sites in radiation oncology. For each case,
we selected the OARs of concern in radiotherapy planning and compared the Dice
and Jaccard outcomes between clinical manual delineation, automatic
segmentation using SAM's "segment anything" mode, and automatic segmentation
using SAM with box prompt. Our results indicate that SAM performs better in
automatic segmentation for the prostate and lung regions, while its performance
in the gastrointestinal and head \& neck regions was relatively inferior. When
considering the size of the organ and the clarity of its boundary, SAM displays
better performance for larger organs with clear boundaries, such as the lung
and liver, and worse for smaller organs with unclear boundaries, like the
parotid and cochlea. These findings align with the generally accepted
variations in difficulty level associated with manual delineation of different
organs at different sites in clinical radiotherapy. Given that SAM, a single
trained model, could handle the delineation of OARs in four regions, these
results also demonstrate SAM's robust generalization capabilities in automatic
segmentation for radiotherapy, i.e., achieving delineation of different
radiotherapy OARs using a generic automatic segmentation model. SAM's
generalization capabilities across different regions make it technically
feasible to develop a generic model for automatic segmentation in radiotherapy
Development of Quantitative Bone SPECT Analysis Methods for Metastatic Bone Disease
Prostate cancer is one of the most prevalent types of cancer in males in the United States. Bone is a common site of metastases for metastatic prostate cancer. However, bone metastases are often considered âunmeasurableâ using standard anatomic imaging and the RECIST 1.1 criteria. As a result, response to therapy is often suboptimally evaluated by visual interpretation of planar bone scintigraphy with response criteria related to the presence or absence of new lesions. With the commercial availability of quantitative single-photon emission computed tomography (SPECT) methods, it is now feasible to establish quantitative metrics of therapy response by skeletal metastases. Quantitative bone SPECT (QBSPECT) may provide the ability to estimate bone lesion uptake, volume, and the number of lesions more accurately than planar imaging. However, the accuracy of activity quantification in QBSPECT relies heavily on the precision with which bone metastases and bone structures are delineated. In this research, we aim at developing automated image segmentation methods for fast and accurate delineation of bone and bone metastases in QBSPECT. To begin, we developed registration methods to generate a dataset of realistic and anatomically-varying computerized phantoms for use in QBSPECT simulations. Using these simulations, we develop supervised computer-automated segmentation methods to minimize intra- and inter-observer variations in delineating bone metastases. This project provides accurate segmentation techniques for QBSPECT and paves the way for the development of QBSPECT methods for assessing bone metastasesâ therapy response
A Geometric Flow Approach for Segmentation of Images with Inhomongeneous Intensity and Missing Boundaries
Image segmentation is a complex mathematical problem, especially for images
that contain intensity inhomogeneity and tightly packed objects with missing
boundaries in between. For instance, Magnetic Resonance (MR) muscle images
often contain both of these issues, making muscle segmentation especially
difficult. In this paper we propose a novel intensity correction and a
semi-automatic active contour based segmentation approach. The approach uses a
geometric flow that incorporates a reproducing kernel Hilbert space (RKHS) edge
detector and a geodesic distance penalty term from a set of markers and
anti-markers. We test the proposed scheme on MR muscle segmentation and compare
with some state of the art methods. To help deal with the intensity
inhomogeneity in this particular kind of image, a new approach to estimate the
bias field using a fat fraction image, called Prior Bias-Corrected Fuzzy
C-means (PBCFCM), is introduced. Numerical experiments show that the proposed
scheme leads to significantly better results than compared ones. The average
dice values of the proposed method are 92.5%, 85.3%, 85.3% for quadriceps,
hamstrings and other muscle groups while other approaches are at least 10%
worse.Comment: Presented at CVIT 2023 Conference. Accepted to Journal of Image and
Graphic
A Novel Mesoscale Modeling of Fracture in Nuclear Fuels
Nuclear fuels power all the commercial carbon-free energy plants and contribute to the fight against climate change. A comprehensive understanding of the fracture behavior of nuclear fuels during normal and transient conditions is still lacking. In this work, we developed a novel Multiphysics mesoscale model that could predict the fracture in different nuclear fuels under various conditions by employing the phase-field modeling of fracture. This work introduces both (1) An experimental study to understand the fuel fracturing behavior of sintered UOâ pellets when exposed to thermal shock, and (2) A Multiphysics phase-field fracture model capable of simulating this process. The model could successfully capture the formation and evolution of cracks in UOâ fuel pellets due to a thermal shock without any ad hoc or a priori assumptions of cracking size, site, thickness, or morphologies. The model was able to capture the overall fracture trends of the corresponding experimental data. Moreover, the model further improved and utilized multi-set order parameters that allowed the simulation of the concurrent crack propagation and microstructure evolution. The new model technique is then validated and employed in an evolved nuclear-grade graphite microstructure to determine the effect of such heterogeneity on the formation and propagation of the cracks along with the variations in the materials' mechanical properties. This new technique advances the fundamental understanding of nuclear fuel behavior under normal and transient conditions and provides a predictive modeling tool for deriving physics-based criteria for the fracture behavior of âthe current and the new nuclear fuel designs
To Serve and Deplete: Exploring Outcomes of Emotional Exhaustion in Servant Leadership and the Moderating Role of Self-Leadership
This study explores the outcomes of emotional exhaustion in servant leadership, a leadership style through which leaders enact influence by serving, empowering, and developing othersâthat is, \u27leading from behind.\u27 Drawing on conservation of resources theory, I explored how servant leadership behaviors may adversely affect the practicing leader through emotional exhaustion and laterally influence the subsequent outcomes of work disengagement and workâfamily conflict. Additionally, I investigated the moderating influence of self-leadership on the relationship between servant leadership and emotional exhaustion. I tested a moderated mediation model with regression analysis using two independent samples of organizational leaders surveyed at two different time points (Sample 1: N = 79; Sample 2: N = 379). The findings did not support a positive relationship between servant leadership and emotional exhaustion but did support positive relationships between emotional exhaustion and work disengagement, and emotional exhaustion and workâfamily conflict. Several limitations of the study are discussed, along with implications and future research directions
Application of knowledge management principles to support maintenance strategies in healthcare organisations
Healthcare is a vital service that touches people's lives on a daily basis by providing treatment and
resolving patients' health problems through the staff. Human lives are ultimately dependent on the skilled
hands of the staff and those who manage the infrastructure that supports the daily operations of the
service, making it a compelling reason for a dedicated research study. However, the UK healthcare sector
is undergoing rapid changes, driven by rising costs, technological advancements, changing patient
expectations, and increasing pressure to deliver sustainable healthcare. With the global rise in healthcare
challenges, the need for sustainable healthcare delivery has become imperative. Sustainable healthcare
delivery requires the integration of various practices that enhance the efficiency and effectiveness of
healthcare infrastructural assets. One critical area that requires attention is the management of
healthcare facilities.
Healthcare facilitiesis considered one of the core elements in the delivery of effective healthcare services,
as shortcomings in the provision of facilities management (FM) services in hospitals may have much more
drastic negative effects than in any other general forms of buildings. An essential element in healthcare
FM is linked to the relationship between action and knowledge. With a full sense of understanding of
infrastructural assets, it is possible to improve, manage and make buildings suitable to the needs of users
and to ensure the functionality of the structure and processes.
The premise of FM is that an organisation's effectiveness and efficiency are linked to the physical
environment in which it operates and that improving the environment can result in direct benefits in
operational performance. The goal of healthcare FM is to support the achievement of organisational
mission and goals by designing and managing space and infrastructural assets in the best combination of
suitability, efficiency, and cost. In operational terms, performance refers to how well a building
contributes to fulfilling its intended functions.
Therefore, comprehensive deployment of efficient FM approaches is essential for ensuring quality
healthcare provision while positively impacting overall patient experiences. In this regard, incorporating
knowledge management (KM) principles into hospitals' FM processes contributes significantly to ensuring
sustainable healthcare provision and enhancement of patient experiences. Organisations implementing
KM principles are better positioned to navigate the constantly evolving business ecosystem easily.
Furthermore, KM is vital in processes and service improvement, strategic decision-making, and
organisational adaptation and renewal.
In this regard, KM principles can be applied to improve hospital FM, thereby ensuring sustainable
healthcare delivery. Knowledge management assumes that organisations that manage their
organisational and individual knowledge more effectively will be able to cope more successfully with the challenges of the new business ecosystem. There is also the argument that KM plays a crucial role in
improving processes and services, strategic decision-making, and adapting and renewing an organisation.
The goal of KM is to aid action â providing "a knowledge pull" rather than the information overload most
people experience in healthcare FM. Other motivations for seeking better KM in healthcare FM include
patient safety, evidence-based care, and cost efficiency as the dominant drivers. The most evidence exists
for the success of such approaches at knowledge bottlenecks, such as infection prevention and control,
working safely, compliances, automated systems and reminders, and recall based on best practices. The
ability to cultivate, nurture and maximise knowledge at multiple levels and in multiple contexts is one of
the most significant challenges for those responsible for KM. However, despite the potential benefits,
applying KM principles in hospital facilities is still limited. There is a lack of understanding of how KM can
be effectively applied in this context, and few studies have explored the potential challenges and
opportunities associated with implementing KM principles in hospitals facilities for sustainable healthcare
delivery.
This study explores applying KM principles to support maintenance strategies in healthcare organisations.
The study also explores the challenges and opportunities, for healthcare organisations and FM
practitioners, in operationalising a framework which draws the interconnectedness between healthcare.
The study begins by defining healthcare FM and its importance in the healthcare industry. It then discusses
the concept of KM and the different types of knowledge that are relevant in the healthcare FM sector.
The study also examines the challenges that healthcare FM face in managing knowledge and how the
application of KM principles can help to overcome these challenges. The study then explores the different
KM strategies that can be applied in healthcare FM. The KM benefits include improved patient outcomes,
reduced costs, increased efficiency, and enhanced collaboration among healthcare professionals.
Additionally, issues like creating a culture of innovation, technology, and benchmarking are considered.
In addition, a framework that integrates the essential concepts of KM in healthcare FM will be presented
and discussed.
The field of KM is introduced as a complex adaptive system with numerous possibilities and challenges.
In this context, and in consideration of healthcare FM, five objectives have been formulated to achieve
the research aim. As part of the research, a number of objectives will be evaluated, including appraising
the concept of KM and how knowledge is created, stored, transferred, and utilised in healthcare FM,
evaluating the impact of organisational structure on job satisfaction as well as exploring how cultural
differences impact knowledge sharing and performance in healthcare FM organisations.
This study uses a combination of qualitative methods, such as meetings, observations, document analysis
(internal and external), and semi-structured interviews, to discover the subjective experiences of
healthcare FM employees and to understand the phenomenon within a real-world context and attitudes of healthcare FM as the data collection method, using open questions to allow probing where appropriate
and facilitating KM development in the delivery and practice of healthcare FM.
The study describes the research methodology using the theoretical concept of the "research onion". The
qualitative research was conducted in the NHS acute and non-acute hospitals in Northwest England.
Findings from the research study revealed that while the concept of KM has grown significantly in recent
years, KM in healthcare FM has received little or no attention. The target population was fifty (five FM
directors, five academics, five industry experts, ten managers, ten supervisors, five team leaders and ten
operatives). These seven groups were purposively selected as the target population because they play a
crucial role in KM enhancement in healthcare FM. Face-to-face interviews were conducted with all
participants based on their pre-determined availability. Out of the 50-target population, only 25 were
successfully interviewed to the point of saturation. Data collected from the interview were coded and
analysed using NVivo to identify themes and patterns related to KM in healthcare FM.
The study is divided into eight major sections. First, it discusses literature findings regarding healthcare
FM and KM, including underlying trends in FM, KM in general, and KM in healthcare FM. Second, the
research establishes the study's methodology, introducing the five research objectives, questions and
hypothesis. The chapter introduces the literature on methodology elements, including philosophical views
and inquiry strategies. The interview and data analysis look at the feedback from the interviews. Lastly, a
conclusion and recommendation summarise the research objectives and suggest further research.
Overall, this study highlights the importance of KM in healthcare FM and provides insights for healthcare
FM directors, managers, supervisors, academia, researchers and operatives on effectively leveraging
knowledge to improve patient care and organisational effectiveness
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