Communities Working for Better Schools

This report is a call to action for community organizations, reformers, and funders to ensure that communities have the information and resources to create sustainable school and community partnerships that result in high-quality, equitable education for all students

Repeated Job Quits: Stepping Stones or Learning about Quality?

Despite the fact that worker quits are often associated with wage gains and higher overall job satisfaction, many workers quit once again within one or two years after changing jobs initially. Such repeated job quit behavior may arise as a stepping stone to better quality jobs (Burdett, 1978) or as a response to unexpectedly low job quality (Jovanovic, 1979). This paper tests the validity of both explanations using data from the UK labor market in order to improve our understanding of job search behavior. Results from panel estimations of job quits and job satisfaction illustrate that the labor market is characterized by elements of both explanations. More specifically, a variance decomposition shows that the stepping stone model explains 80 percent of repeated job quit behavior; the remaining 20 percent is the result of learning about job quality. Hence, workers appear to need several job quits to find their most preferred job and multiple job quits serve as a stepping stone to more satisfaction at work.labor mobility, job satisfaction, job search

Bohr-Sommerfeld conditions for several commuting Hamiltonians

The goal of this paper is to find the quantization conditions of Bohr-Sommerfeld of k quantum Hamiltonians acting on the euclidian space of dimension n, depending on a small parameter h, and which commute to each other. That is we determine, around a regular energy level E of the euclidian space of dimension k the principal term of the asymptotics in h of the eigenvalues of the operators that are associated to a common eigenfunction. Thus we localize the so-called joint spectrum of the operators. Under the assumption that the classical Hamiltonian flow of the joint principal symbol is periodic with constant periods on the energy level of E(a submanifold of codimension k) we prove that the part of the joint spectrum lying in a small neighbourhood of E is localized near a lattice of size h determined in terms of actions and Maslov indices. The multiplicity of the spectrum is also determined.Comment: 18 pages, LaTe

New stability results for long-wavelength convection patterns

We consider the transition from a spatially uniform state to a steady, spatially-periodic pattern in a partial differential equation describing long-wavelength convection. This both extends existing work on the study of rolls, squares and hexagons and demonstrates how recent generic results for the stability of spatially-periodic patterns may be applied in practice. We find that squares, even if stable to roll perturbations, are often unstable when a wider class of perturbations is considered. We also find scenarios where transitions from hexagons to rectangles can occur. In some cases we find that, near onset, more exotic spatially-periodic planforms are preferred over the usual rolls, squares and hexagons.Comment: 25 pages, 8 figure

Repeated Job Quits: Stepping stones or learning about quality?

Despite the fact that worker quits are often associated with wage gains and higheroverall job satisfaction, many workers quit once again within one or two years afterchanging jobs initially. Such repeated job quit behavior may arise as a steppingstone to better quality jobs (Burdett, 1978) or as a response to unexpectedly lowjob quality (Jovanovic, 1979).This paper tests the validity of both explanations using data from the UK labormarket in order to improve our understanding of job search behavior. Results frompanel estimations of job quits and job satisfaction illustrate that the labor market ischaracterized by elements of both explanations. More specifically, a variancedecomposition shows that the stepping stone model explains 80 percent ofrepeated job quit behavior; the remaining 20 percent is the result of learning aboutjob quality. Hence, workers appear to need several job quits to find their mostpreferred job and multiple job quits serve as a stepping stone to more satisfaction atwork.education, training and the labour market;

Apparatus and method for explosive bonding to edge of flyer plate

The invention is an apparatus and a process for the explosive joining of a flyer plate and a base plate. The apparatus consists of a flyer plate positioned over a base plate. The flyer plate has a notch containing a filler material in intimate contact with the flyer plate. An adhesive means holds a ribbon explosive partially overlapping the notch in the flyer plate. A detonating means initiates the ribbon explosive that drives the flyer plate to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and effacing bonding, resulting in electron sharing linkups between the plates. An unbonded tab fractures at a base of the notch leaving a bond to an edge of the attached flyer plate

Machine Learning Based Auto-tuning for Enhanced OpenCL Performance Portability

Heterogeneous computing, which combines devices with different architectures, is rising in popularity, and promises increased performance combined with reduced energy consumption. OpenCL has been proposed as a standard for programing such systems, and offers functional portability. It does, however, suffer from poor performance portability, code tuned for one device must be re-tuned to achieve good performance on another device. In this paper, we use machine learning-based auto-tuning to address this problem. Benchmarks are run on a random subset of the entire tuning parameter configuration space, and the results are used to build an artificial neural network based model. The model can then be used to find interesting parts of the parameter space for further search. We evaluate our method with different benchmarks, on several devices, including an Intel i7 3770 CPU, an Nvidia K40 GPU and an AMD Radeon HD 7970 GPU. Our model achieves a mean relative error as low as 6.1%, and is able to find configurations as little as 1.3% worse than the global minimum.Comment: This is a pre-print version an article to be published in the Proceedings of the 2015 IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW). For personal use onl