Analysis of some acoustics-jet flow interaction problems

Analytical problems in the interactions between the mean-shear flows and the acoustic field in the planar and circular jets are examined. These problems are basic in understanding the effects of coherent large structure on the generation and complications of sound in a sub-sonic jet. Three problems were investigated: (1) spatial (vs. temporal) normal mode analysis in a planar jets; (2) a slightly divergent, planar jet; and (3) acoustic waves in an axisymmetrical jet

Ricci flows with unbounded curvature

We show that any noncompact Riemann surface admits a complete Ricci flow g(t), t\in[0,\infty), which has unbounded curvature for all t\in[0,\infty).Comment: 12 pages, 1 figure; updated reference

Evaluation of an indigenous early intervention model for Chinese persons with early dementia

ePoster Session 6: Strengthening the social and cultural wellbeing of individuals, families and communities – promoting resilience, empowerment, safety and respectConference Theme: Promoting Social and Economic Equality: Responses from Social Work and Social DevelopmentIntroduction: The World Health Organization considers Dementia as a public health priority. The ageing population logicaly implies a growing population in persons with Dementia. Tung Wah Group of Hospitals started the Circle of Care project in 209. Integrating the Chinese cultural concept of body and mind linkage, the organization developed an evidence-driven, culturaly sensitve and holistic intervention for persons with early Dementia. Aims: This study is to evaluate the efectivenes of this pilot care intervention. Methodology: The study adopted a quasi-experimental design. Al the older adults who joined the programme were invited to join the study as participants of the intervention group. Older adults with a compatible mental abilty recruited from a Day Care Centre in the same district were invited to join as participants of the comparison group. The participants in the intervention group were interviewed before the intervention (t0), right after the intervention (t1) and 3 months after the intervention (t2). Information was colected from the care-givers as wel. As for the participants in the comparison group, interviews were ofered at t0 and t2 only. Dependent variables include the cognitve abilty, physical abilty, quality of life and depresion of the older adults as wel as the perceived relationship betwen the older adults and the carers. Findings: Thirty-two older adults and 31 carers joined the intervention group with 2 older adults in the comparison group. The within group analysis of the intervention group showed statistical signifcant changes in the cognitve abilty, quality of life and depresed mod of the older adults. The betwen group analysis indicated diferences in expected direction. In particular, the changes in functional reach test, depresion and quality of life were with statistical signifcance. Conclusion: The pilot study shows that he intervention is efective.published_or_final_versio

Finite Element Solution of Axisymmetrical Dynamic Problems of Shells of Revolution

Finite element solution for natural frequencies and mode shapes of free axisymmetrical vibrations and dynamic response of arbitrary rotationally symmetric shell

An efficient sparse conjugate gradient solver using a Beneš permutation network

© 2014 Technical University of Munich (TUM).The conjugate gradient (CG) is one of the most widely used iterative methods for solving systems of linear equations. However, parallelizing CG for large sparse systems is difficult due to the inherent irregularity in memory access pattern. We propose a novel processor architecture for the sparse conjugate gradient method. The architecture consists of multiple processing elements and memory banks, and is able to compute efficiently both sparse matrix-vector multiplication, and other dense vector operations. A Beneš permutation network with an optimised control scheme is introduced to reduce memory bank conflicts without expensive logic. We describe a heuristics for offline scheduling, the effect of which is captured in a parametric model for estimating the performance of designs generated from our approach

Averaging approximation to singularly perturbed nonlinear stochastic wave equations

An averaging method is applied to derive effective approximation to the following singularly perturbed nonlinear stochastic damped wave equation \nu u_{tt}+u_t=\D u+f(u)+\nu^\alpha\dot{W} on an open bounded domain $D\subset\R^n$\,, $1\leq n\leq 3$\,. Here $\nu>0$ is a small parameter characterising the singular perturbation, and $\nu^\alpha$\,, $0\leq \alpha\leq 1/2$\,, parametrises the strength of the noise. Some scaling transformations and the martingale representation theorem yield the following effective approximation for small $\nu$, u_t=\D u+f(u)+\nu^\alpha\dot{W} to an error of \ord{\nu^\alpha}\,.Comment: 16 pages. Submitte

Distributed Random Process for a Large-Scale Peer-to-Peer Lottery

Most online lotteries today fail to ensure the verifiability of the random process and rely on a trusted third party. This issue has received little attention since the emergence of distributed protocols like Bitcoin that demonstrated the potential of protocols with no trusted third party. We argue that the security requirements of online lotteries are similar to those of online voting, and propose a novel distributed online lottery protocol that applies techniques developed for voting applications to an existing lottery protocol. As a result, the protocol is scalable, provides efficient verification of the random process and does not rely on a trusted third party nor on assumptions of bounded computational resources. An early prototype confirms the feasibility of our approach

Yang-Mills Flow and Uniformization Theorems

We consider a parabolic-like systems of differential equations involving geometrical quantities to examine uniformization theorems for two- and three-dimensional closed orientable manifolds. We find that in the two-dimensional case there is a simple gauge theoretic flow for a connection built from a Riemannian structure, and that the convergence of the flow to the fixed points is consistent with the Poincare Uniformization Theorem. We construct a similar system for the three-dimensional case. Here the connection is built from a Riemannian geometry, an SO(3) connection and two other 1-form fields which take their values in the SO(3) algebra. The flat connections include the eight homogeneous geometries relevant to the three-dimensional uniformization theorem conjectured by W. Thurston. The fixed points of the flow include, besides the flat connections (and their local deformations), non-flat solutions of the Yang-Mills equations. These latter "instanton" configurations may be relevant to the fact that generic 3-manifolds do not admit one of the homogeneous geometries, but may be decomposed into "simple 3-manifolds" which do.Comment: 21 pages, Latex, 5 Postscript figures, uses epsf.st