6,478 research outputs found
Doing Science: How to optimise patient and public involvement in your research
This paper considers how best to achieve patient and public involvement in research and how to get the most out of it http://ow.ly/R0hwV
Doing Science: How to optimise patient and public involvement in your research
This paper considers how best to achieve patient and public involvement in research and how to get the most out of it http://ow.ly/R0hw
A Procedure For Selecting A Best Multinomial Distribution With Application To Population Income Mobility
A procedure is developed for selecting a subset which is asserted to contain the “best” of several multinomial populations with a pre-assigned probability of correct selection. According to a pre-chosen linear combination of the multinomial cell probabilities, the “best” population is defined to be the one with the highest such linear combination. As an illustration, the proposed procedure is applied to data relating to the economics of happiness and population income mobility
A Nonparametric Test For Homogeneity Of Variances: Application To GPAs Of Students Across Academic Majors
We propose a nonparametric (or distribution-free) procedure for testing the equality of several population variances (or scale parameters). The proposed test is a modification of Bakir’s (1989, Commun. Statist., Simul-Comp., 18, 757-775) analysis of means by ranks (ANOMR) procedure for testing the equality of several population means. A proof is given to establish the distribution-free property of the modified procedure. The proposed procedure is then applied to test whether or not the variability in the grade point averages (GPAs) of students differs across five business academic majors. We collect the GPAs (observations) of a random sample of students from each major under study. The absolute deviations of the observations from the overall median of the combined sample are then calculated and ranked from least to largest. The average ranks and two decision lines are then plotted on a graph paper to detect not only the existence of significant differences among variances, but also to pinpoint which variances are causing those differences
Improved numerical methods for infinite spin chains with long-range interactions
We present several improvements of the infinite matrix product state (iMPS)
algorithm for finding ground states of one-dimensional quantum systems with
long-range interactions. As a main new ingredient we introduce the superposed
multi-optimization (SMO) method, which allows an efficient optimization of
exponentially many MPS of different length at different sites all in one step.
Hereby the algorithm becomes protected against position dependent effects as
caused by spontaneously broken translational invariance. So far, these have
been a major obstacle to convergence for the iMPS algorithm if no prior
knowledge of the systems translational symmetry was accessible. Further, we
investigate some more general methods to speed up calculations and improve
convergence, which might be partially interesting in a much broader context,
too. As a more special problem, we also look into translational invariant
states close to an invariance braking phase transition and show how to avoid
convergence into wrong local minima for such systems. Finally, we apply the new
methods to polar bosons with long-range interactions. We calculate several
detailed Devil's Staircases with the corresponding phase diagrams and
investigate some supersolid properties.Comment: Main text: 17 pages plus references, 8 figures. Supplementary info: 6
pages. v2: improved presentation and more results adde
Optimisation of on-line principal component analysis
Different techniques, used to optimise on-line principal component analysis,
are investigated by methods of statistical mechanics. These include local and
global optimisation of node-dependent learning-rates which are shown to be very
efficient in speeding up the learning process. They are investigated further
for gaining insight into the learning rates' time-dependence, which is then
employed for devising simple practical methods to improve training performance.
Simulations demonstrate the benefit gained from using the new methods.Comment: 10 pages, 5 figure
- …