Parallel algorithm for singular value decomposition as applied to failure tolerant manipulators, A

Includes bibliographical references (pages [348-349]).The system of equations that govern kinematically redundant manipulators is commonly solved by finding the singular value decomposition (SVD) of the corresponding Jacobian matrix. This can require considerable amounts of time to compute, thus a parallel SVD algorithm minimizing execution time is sought. The approach employed here lends itself to parallelization by using Givens rotations and information from previous decompositions. The key contributions of this research include the presentation and implementation of a new variation of a parallel SVD algorithm to compute the SVD for a set of post-fault Jacobians. Results from implementation of the algorithm on a MasPar MP-1 and an IBM SP2 are provided. Specific issues considered for each implementation include how data is mapped to the processing elements, the effect that increasing the number of processing elements has on execution time, and the type of parallel architecture used

Static mapping heuristics for tasks with dependencies, priorities, deadlines, and multiple versions in heterogeneous environments

Includes bibliographical references.Heterogeneous computing (HC) environments composed of interconnected machines with varied computational capabilities are well suited to meet the computational demands of large, diverse groups of tasks. The problem of mapping (defined as matching and scheduling) these tasks onto the machines of a distributed HC environment has been shown, in general, to be NP-complete. Therefore, the development of heuristic techniques to find near-optimal solutions is required. In the HC environment investigated, tasks had deadlines, priorities, multiple versions, and may be composed of communicating subtasks. The best static (off-line) techniques from some previous studies were adapted and applied to this mapping problem: a genetic algorithm (GA), a GENITOR-style algorithm, and a greedy Min-min technique. Simulation studies compared the performance of these heuristics in several overloaded scenarios, i.e., not all tasks executed. The performance measure used was a sum of weighted priorities of tasks that completed before their deadline, adjusted based on the version of the task used. It is shown that for the cases studied here, the GENITOR technique found the best results, but the faster Min-min approach also performed very well.This research was supported in part by the DARPA/ITO Quorum Program under GSA subcontract number GS09K99BH0250 and a Purdue University Dean of Engineering Donnan Scholarship

Level spacings at the metal-insulator transition in the Anderson Hamiltonians and multifractal random matrix ensembles

We consider orthogonal, unitary, and symplectic ensembles of random matrices with (1/a)(ln x)^2 potentials, which obey spectral statistics different from the Wigner-Dyson and are argued to have multifractal eigenstates. If the coefficient $a$ is small, spectral correlations in the bulk are universally governed by a translationally invariant, one-parameter generalization of the sine kernel. We provide analytic expressions for the level spacing distribution functions of this kernel, which are hybrids of the Wigner-Dyson and Poisson distributions. By tuning the single parameter, our results can be excellently fitted to the numerical data for three symmetry classes of the three-dimensional Anderson Hamiltonians at the metal-insulator transition, previously measured by several groups using exact diagonalization.Comment: 12 pages, 8 figures, REVTeX. Additional figure and text on the level number variance, to appear in Phys.Rev.

Clotting activity of polyphosphate-functionalized silica nanoparticles

We present a silica nanoparticle (SNP) functionalized with polyphosphate (polyP) that accelerates the natural clotting process of the body. SNPs initiate the contact pathway of the blood-clotting system; short-chain polyP accelerates the common pathway by the rapid formation of thrombin, which enhances the overall blood-clotting system, both by accelerating fibrin generation and by facilitating the regulatory anticoagulation mechanisms essential for hemostasis. Analysis of the clotting properties of bare SNPs, bare polyP, and polyP-functionalized SNPs in plasma demonstrated that the attachment of polyP to SNPs to form polyP-SNPs creates a substantially enhanced synergistic effect that lowers clotting time and increases thrombin production at low concentrations. PolyP-SNP even retains its clotting function at ambient temperature. The polyP-SNP system has the potential to significantly improve trauma-treatment protocols and outcomes in hospital and prehospital settings

Dynamically mapping tasks with priorities and multiple deadlines in a heterogeneous environment

Includes bibliographical references (pages 166-167).In a distributed heterogeneous computing system, the resources have different capabilities and tasks have different requirements. To maximize the performance of the system, it is essential to assign the resources to tasks (match) and order the execution of tasks on each resource (schedule) to exploit the heterogeneity of the resources and tasks. Dynamic mapping (defined as matching and scheduling) is performed when the arrival of tasks is not known a priori. In the heterogeneous environment considered in this study, tasks arrive randomly, tasks are independent (i.e., no inter-task communication), and tasks have priorities and multiple soft deadlines. The value of a task is calculated based on the priority of the task and the completion time of the task with respect to its deadlines. The goal of a dynamic mapping heuristic in this research is to maximize the value accrued of completed tasks in a given interval of time. This research proposes, evaluates, and compares eight dynamic mapping heuristics. Two static mapping schemes (all arrival information of tasks are known) are designed also for comparison. The performance of the best heuristics is 84% of a calculated upper bound for the scenarios considered

A Brownian Motion Model of Parametric Correlations in Ballistic Cavities

A Brownian motion model is proposed to study parametric correlations in the transmission eigenvalues of open ballistic cavities. We find interesting universal properties when the eigenvalues are rescaled at the hard edge of the spectrum. We derive a formula for the power spectrum of the fluctuations of transport observables as a response to an external adiabatic perturbation. Our formula correctly recovers the Lorentzian-squared behaviour obtained by semiclassical approaches for the correlation function of conductance fluctuations.Comment: 19 pages, written in RevTe

Art therapy with refugee children: a qualitative study explored through the lens of art therapists and their experiences

This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Art Therapy on 9-11-2018, available online: https://doi.org/10.1080/17454832.2018.1533571This article sets out to explore the use of art therapy with refugee children, from the perspective of art therapists and their experiences. Three semi-structured interviews were conducted to gain insights by capturing experiences and stories. Using thematic analysis, five themes were identified: (1) giving voice; (2) rebuilding trust, opening wounds; (3) sharing stories, healing pain; (4) exploring identity, discovering new-self; and (5) understanding art therapy. Upon reflection, two key aspects of art therapy were established, these were identified as: (1) providing refugee children with a safe space to heal and discover new-self, and (2) giving refugee children a voice to express and share stories. Despite the last of the five themes (understanding art therapy) being established as a factor that limits the use of art therapy, this has created an avenue for further research. From the findings, it was concluded that art therapy can be a useful form of psychotherapy for refugee children. Art therapy can provide these children with a safe space to heal, and give them a voice to be heard

Caseload midwifery as organisational change:the interplay between professional and organisational projects in Denmark

BACKGROUND: The large obstetric units typical of industrialised countries have come under criticism for fragmented and depersonalised care and heavy bureaucracy. Interest in midwife-led continuity models of care is growing, but knowledge about the accompanying processes of organisational change is scarce. This study focuses on midwives’ role in introducing and developing caseload midwifery. Sociological studies of midwifery and organisational studies of professional groups were used to capture the strong interests of midwives in caseload midwifery and their key role together with management in negotiating organisational change. METHODS: We studied three hospitals in Denmark as arenas for negotiating the introduction and development of caseload midwifery and the processes, interests and resources involved. A qualitative multi-case design was used and the selection of hospitals aimed at maximising variance. Ten individual and 14 group interviews were conducted in spring 2013. Staff were represented by caseload midwives, ward midwives, obstetricians and health visitors, management by chief midwives and their deputies. Participants were recruited to maximise the diversity of experience. The data analysis adopted a thematic approach, using within- and across-case analysis. RESULTS: The analysis revealed a highly interdependent interplay between organisational and professional projects in the change processes involved in the introduction and development of caseload midwifery. This was reflected in three ways: first, in the key role of negotiations in all phases; second, in midwives’ and management’s engagement in both types of projects (as evident from their interests and resources); and third in a high capacity for resolving tensions between the two projects. The ward midwives’ role as a third party in organisational change further complicated the process. CONCLUSIONS: For managers tasked with the introduction and development of caseload midwifery, our study underscores the importance of understanding the complexity of the underlying change processes and of activating midwives’ and managers’ interests and resources in addressing the challenges. Further studies of female-dominated professions such as midwifery should offer good opportunities for detailed analysis of the deep-seated interdependence of professional and organisational projects and for identifying the key dimensions of this interdependence

A qualitative study of health care professionals' views and experiences of paediatric advance care planning

Background Good end-of-life care planning is vital to ensure optimal care is provided for patients and their families. Two key factors are open and honest advance care planning conversations between the patient (where possible), family, and health care professionals, focusing on exploring what their future wishes are; and the development of an advance care plan document. However, in paediatric and neonatal settings, there has been little research to demonstrate how advance care planning conversations take place. This study explored health care professionals’ views and experiences of paediatric advance care planning in hospitals, community settings and hospices. MethodsA qualitative methodology was employed using purposive sampling of health care professionals involved in the end-of-life care for children aged 0–18 years known to the hospital palliative care team, and had died at least three months before, but less than 18 months prior to the study. Ethics committee approval was obtained for the study. Located in the North of England, the study involved three hospitals, a children’s hospice, and community services. Data were collected using semi-structured, digitally recorded, telephone interviews. All interviews were transcribed verbatim and subjected to thematic analysis. ResultsTwenty-one health care professionals participated, including generalist paediatric staff as well as specialist palliative care staff.Two themes were generated from the study: The timing of planning conversations, including waiting for the relationship with the family to form; the introduction of parallel planning; avoiding a crisis situation. Secondly, supporting effective conversations around advance care planning, including where to have the conversation; introducing the conversation; and how to approach the topic encompassing the value of advance care planning and documentation for families. Conclusion The timing of when to start the advance care planning conversations remains an issue for health care professionals. The value of doing it in stages and considering the environment where the conversations are held was noted. Timely planning was seen as vital to avoid difficult conversations at a crisis point and for co-ordination of care. Good advance care planning is to provide the best person-centred care for the child and experience for the family