Smoothed Boundary Method for Solving Partial Differential Equations with General Boundary Conditions on Complex Boundaries

In this article, we describe an approach for solving partial differential equations with general boundary conditions imposed on arbitrarily shaped boundaries. A function that has a prescribed value on the domain in which a differential equation is valid and smoothly but rapidly varying values on the boundary where boundary conditions are imposed is used to modify the original differential equations. The mathematical derivations are straight forward, and generically applicable to a wide variety of partial differential equations. To demonstrate the general applicability of the approach, we provide four examples: (1) the diffusion equation with both Neumann and Dirichlet boundary conditions, (2) the diffusion equation with surface diffusion, (3) the mechanical equilibrium equation, and (4) the equation for phase transformation with additional boundaries. The solutions for a few of these cases are validated against corresponding analytical and semi-analytical solutions. The potential of the approach is demonstrated with five applications: surface-reaction diffusion kinetics with a complex geometry, Kirkendall-effect-induced deformation, thermal stress in a complex geometry, phase transformations affected by substrate surfaces, and a self-propelling droplet.Comment: A better smooth algorithm has been developed and tested, will soon replace Eq. 58 in page 16. We have also developed a level-set moving boundary SBM method, and it will replace the Navier-Stokes-Cahn-Hilliard type domain parameter tracking method in Section 5.

Does unemployment have asymmetric effects on suicide rates? Evidence from the United States: 1928–2013

This study applied the recently developed asymmetric causality test and asymmetric generalised impulse-response method to demonstrate the dynamic relationship between unemployment and suicide rates in the U.S. over the period of 1928–2013. The results suggest that there exist asymmetric effects of unemployment on suicide rates. An economic recession (in terms of an increase in unemployment rate) is more likely to increase the suicide rate among an old age group (55–64 years old) than among other age groups, while an economic expansion (in terms of a decrease in unemployment rate) is more likely to reduce the suicide rate of young (15–24 and 25–34 years old) and middle age groups (35–44 and 45– 54 years old) than their counterpart. Therefore, policy implications generated from our results include the following: that intervention to prevent suicidal behaviour should be directed more towards the older age group during economic recession and that we may expect that an economic expansion may not result in a great reduction of suicide rates for the old age (55–64 years) group

尝试使用IM公众平台提高医院管理水平

Thisarticle has analyzed the contribution of modern IT to hospital management: using public platform of IM (instant message/communication) will make it more convenient and efficient to conduct communication with (prior to the treatment), conduct treatment, and provide post-treatment service for patients and their family; withthe set-up of a smooth and efficient information channel set up, the relationship between patients and doctors will be greatly improved ,thus reputation and credibility of the hospital and its doctors will be promoted; when the public has better received the hospital and its doctors, social harmony will be achieved. 本文分析了现代信息技术对医院建设的作用，利用IM（即时通讯）的公众平台与病人及其家属以及潜在的病人做好病前沟通、病中医疗、病后服务，最大程度方便病人，医患之间建立一个良好的信息通道，可大大改善医患之间的关系，进一步提高医院的品牌和医生的知名度，以获得公众的认可，使社会进一步和谐

An Analysis of Thickness-shear Vibrations of an Annular Plate with the Mindlin Plate Equations

The Mindlin plate equations with the consideration of thickness-shear deformation as an independent variable have been used for the analysis of vibrations of quartz crystal resonators of both rectangular and circular types. The Mindlin or Lee plate theories that treat thickness-shear deformation as an independent higher-order vibration mode in a coupled system of two-dimensional variables are the choice of theory for analysis. For circular plates, we derived the Mindlin plate equations in a systematic manner as demonstrated by Mindlin and others and obtained the truncated two-dimensional equations of closely coupled modes in polar coordinates. We simplified the equations for vibration modes in the vicinity of fundamental thickness-shear frequency and validated the equations and method. To explore newer structures of quartz crystal resonators, we utilized the Mindlin plate equations for the analysis of annular plates with fixed inner and free outer edges for frequency spectra. The detailed analysis of vibrations of circular plates for the normalized frequency versus dimensional parameters provide references for optimal selection of parameters based on the principle of strong thickness-shear mode and minimal presence of other modes to enhance energy trapping through maintaining the strong and pure thickness-shear vibrations insensitive to some complication factors such as thermal and initial stresses.Comment: Paper to be presented to the 2015 IEEE International Frequency Control Symposium and European Frequency and Time Forum, Denver, CO, USA. April 12-16, 201

Real-time scheduling algorithms in wireless sensor networks

Wireless sensor networks have recently attracted research and industry interest. Wireless sensor networks have great potential to be used in many applications because of their unique characteristics. In many applications, such as military battlefield surveillance and medical health care, the data packets need to be delivered to their destinations with real-time constraints. Traditional real-time algorithms cannot be directly used in wireless sensor networks. Therefore, a new challenge in wireless sensor networks arises. In this thesis, we proposed several new real-time scheduling algorithms for wireless sensor networks. Unlike other existing real-time scheduling algorithms, we design real-time scheduling algorithms that not only consider the current situations of packets but also take the travelling history of packets into consideration. We evaluated these algorithms both in terms of the packet delivery rate and fairness to different flows. Finally we extended IEEE 802.11 to be able to prioritize the packets. We implemented these algorithms in NS-2 and extensively evaluated the experimental results. The results demonstrate that our new algorithms efficiently increase the system real-time performance and fairness