46,586 research outputs found
On the origin of the deflection of light
Action at distance in Newtonian physics is replaced by finite propagation
speeds in classical post--Newtonian physics. As a result, the differential
equations of motion in Newtonian physics are replaced by functional
differential equations, where the delay associated with the finite propagation
speed is taken into account. Newtonian equations of motion, with
post--Newtonian corrections, are often used to approximate the functional
differential equations. In ``On the origin of quantum mechanics'', preprint,
physics/0505181, May 2005, a simple atomic model based on a functional
differential equation which reproduces the quantized Bohr atomic model was
presented. The unique assumption was that the electrodynamic interaction has a
finite propagation speed. In ``On the origin of the gravitational quantization:
The Titius--Bode Law'', preprint, physics/0507072, Jul 2005, a simple
gravitational model based on a functional differential equation which gives a
gravitational quantification and an explanation of the modified Titius--Bode
law is described. In ``On the origin of the anomalous precession of Mercury's
perihelion'', preprint, physics/0510086, Oct 2005, an explanation of the
anomalous precession of Mercury's perihelion is given in terms of a simple
retarded potential, which, at first order, coincides with Gerber's potential of
1898, and which agrees with the author's previous works. In this paper, it is
shown how the simple retarded potential presented in physics/0510086 also gives
the correct value of the gravitational deflection of fast particles of General
Relativity.Comment: 10 pages, 2 figure
Graph Element Networks: adaptive, structured computation and memory
We explore the use of graph neural networks (GNNs) to model spatial processes
in which there is no a priori graphical structure. Similar to finite element
analysis, we assign nodes of a GNN to spatial locations and use a computational
process defined on the graph to model the relationship between an initial
function defined over a space and a resulting function in the same space. We
use GNNs as a computational substrate, and show that the locations of the nodes
in space as well as their connectivity can be optimized to focus on the most
complex parts of the space. Moreover, this representational strategy allows the
learned input-output relationship to generalize over the size of the underlying
space and run the same model at different levels of precision, trading
computation for accuracy. We demonstrate this method on a traditional PDE
problem, a physical prediction problem from robotics, and learning to predict
scene images from novel viewpoints.Comment: Accepted to ICML 201
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Being Different Yet Feeling Similar: The Influence Of Demographic Composition And Organizational Culture On Work Processes And Outcomes
Drawing from self-categorization theory, we tested hypotheses on the effects of an organization's demographic composition and cultural emphasis on work processes and outcomes. Using an organizational simulation, we found that the extent to which an organization emphasized individualistic or collectivistic values interacted with demographic composition to influence social interaction, conflict, productivity, and perceptions of creativity among 258 MBA students. Our findings suggest that the purported benefits of demographic diversity are more likely to emerge in organizations that, through their culture, make organizational membership salient and encourage people to categorize one another as having the organization's interests in common, rather than those that emphasize individualism and distinctiveness among members.(.)Managemen
The implicit relational assessment procedure: emerging reliability and validity data
The Implicit Relational Assessment Procedure (IRAP) is a measure of âimplicit cognition' developed on the basis of a contemporary behavioural analysis of language and cognition. The IRAP has now been applied to a range of foci over five years of published research. A frequently-cited caveat in publications to date is the need for further research to gauge the reliability and validity of the IRAP as an implicit measure. This review paper will provide a critical synthesis of available evidence for reliability and validity. The review applies a multifaceted test-theory approach to validity, and reliability is assessed through meta-analysis of published data. The discussion critically considers reviewed IRAP evidence with reference to the extant literature on alternative implicit measures, limitations of studies to date, and consideration of broader conceptual issues
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Loneliness and life satisfaction amongst three cultural groups
Abstract
Studies into loneliness and life satisfaction have rarely assessed the role of culture in moderating the
relationship between these variables. The present study examined the relationship between loneliness and life
satisfaction using data from three nonstudent samples collected from Italian, Anglo-Canadian and
Chinese-Canadian populations. A total of 206 respondents completed the Revised UCLA Loneliness Scale
(Russell, Peplau, & Cutrona, 1980) and the Satisfaction with Life Scale (Diener, Emmons, Larsen, & Griffin,
1985). Two contrasting hypotheses were compared: one, a âpostmodernâ hypothesis, predicting that the
relationship between life satisfaction and loneliness would be stronger in our individualist sample of
Anglo-Canadians, and a second, ârelationalâ hypothesis predicting this association to be strongest in our
collectivist, Chinese-Canadian sample. Our findings demonstrated that culture has a small but significant
impact on the relationship between loneliness and life satisfaction, and, consistent with the relational
hypothesis, the relationship between the two concepts was strongest among our Chinese-Canadian
respondents and weakest among our Anglo-Canadian participants This finding is discussed in the context
of the strong expectations of social cohesion in collectivist societies
A particle swarm optimisation-based Grey prediction model for thermal error compensation on CNC machine tools
Thermal errors can have a significant effect on CNC machine tool accuracy. The thermal error compensation system has become a cost-effective method of improving machine tool accuracy in recent years. In the presented paper, the Grey relational analysis (GRA) was employed to obtain the similarity degrees between fixed temperature sensors and the thermal response of the CNC machine tool structure. Subsequently, a new Grey model with convolution integral GMC(1, N) is used to design a thermal prediction model. To improve the accuracy of the proposed model, the generation coefficients of GMC(1, N) are calibrated using an adaptive Particle Swarm Optimisation (PSO) algorithm. The results demonstrate good agreement between the experimental and predicted thermal error. Finally, the capabilities and the limitations of the model for thermal error compensation have been discussed.
Keywords: CNC machine tool, Thermal error modelling, ANFIS, Fuzzy logic, Grey system theory
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