928 research outputs found
Alignment And Matching In Multi-purpose Household Microsimulations
Household microsimulations are often required to align with deterministic projections from other sources. This paper suggests the use of random sampling within alignment pools to give one-pass event alignment. An iterative process is suggested for alignment of person types, but gives disturbingly high numbers of changes. Type alignment may be better done by manually adjusting assumptions to give approximate alignment. Many forms of matching are needed in household microsimulations. The paper suggests two different immediate matching methods - probability-weighted, and best of n. Performance measures are derived for these methods, and for two existing batch methods - stochastic and order of decreasing difficulty. Probability-weighted matching gave slightly better results than best of n and stochastic, and order of decreasing difficulty gave poor results. The suggested matching methods may be useful in a wide range of applications.alignment, marriage market, performance measures
Lesbian, Gay and Bisexual Curricular Integration at a Womenâs College, or Discussions in (and of) the Dating Parlor
Proposal for a presentation on integrating LGB studies into a womenâs college in the southern United State
Poster Session: Improving Student Success Through Curriculum Design with OER.
This poster details the effects of integrating OER into curriculum design at the College of Lake County. It offers insight into how design and open course materials can improve student performance
New techniques for household microsimulation, and their application to Australia
Household microsimulation models are sometimes used by national governments to make long-term projections of proposed policy changes. They are costly to develop and maintain, and sometimes have short lifetimes. Most present national models have limited interactions between agents, few regions and long simulation cycles. Some models are very slow to run. Overcoming these limitations may open up a much wider range of government, business and individual uses.
This thesis suggests techniques to help make multi-purpose dynamic microsimulations of households, with fine spatial resolutions, high sampling densities and short simulation cycles. Techniques suggested are: * simulation by sampling with loaded probabilities
* proportional event alignment
* event alignment using random sampling
* immediate matching by probability-weighting
* immediate 'best of n' matching.
All of these techniques are tested in artificial situations. Three of them - sampling with loaded probabilities, alignment using random sampling and best of n matching - are successfully tested in the Cumpston model, a household microsimulation model developed for this thesis.
Sampling with loaded probabilities is found to give almost identical results to the traditional all-case sampling, but be quicker. The suggested alignment and matching techniques are shown to give less distortion and generally lower runtimes than some techniques currently in use.
The Cumpston model is based on a 1% sample from the 2001 Australian census. Individuals, families, households and dwellings are included. Immigration and emigration are separately simulated, together with internal migration between 57 statistical divisions. Transitions between 8 person types are simulated, and between 9 occupations. The model projects education, employment, earnings and retirement savings for each individual, and dwelling values, rents and housing loans for each household. The onset and development of diseases for each individual are simulated. Validation of the model was based on methods used by the Orcutt, CORSIM, DYNACAN and APPSIM models. Iterative methods for model calibration are described, together with a statistical test for creep in multiple runs.
The model takes about 85 seconds to make projections for 50 years with yearly simulation cycles. After standardizing for sample size and projection years, this is a little slower than the fastest national models currently operating. A planned extension of the model is to 2.2 million persons over 2,214 areas, synthesized from 2011 census tabulations. Using multithreading where feasible, a 50-year projection may take about 10 minutes
The use of âPICO for synthesisâ and methods for synthesis without meta-analysis: protocol for a survey of current practice in systematic reviews of health interventions
INTRODUCTION: Systematic reviews involve synthesis of research to inform decision making by clinicians, consumers, policy makers and researchers. While guidance for synthesis often focuses on meta-analysis, synthesis begins with specifying the âPICO for each synthesisâ (i.e. the criteria for deciding which populations, interventions, comparators and outcomes are eligible for each analysis). Synthesis may also involve the use of statistical methods other than meta-analysis (e.g. vote counting based on the direction of effect, presenting the range of effects, combining P values) augmented by visual display, tables and text-based summaries. This study examines these two aspects of synthesis.
OBJECTIVES: To identify and describe current practice in systematic reviews of health interventions in relation to: (i) approaches to grouping and definition of PICO characteristics for synthesis; and (ii) methods of summary and synthesis when meta-analysis is not used.
METHODS: We will randomly sample 100 systematic reviews of the quantitative effects of public health and health systems interventions published in 2018 and indexed in the Health Evidence and Health Systems Evidence databases. Two authors will independently screen citations for eligibility. Two authors will confirm eligibility based on full text, then extract data for 20% of reviews on the specification and use of PICO for synthesis, and the presentation and synthesis methods used (e.g. statistical synthesis methods, tabulation, visual displays, structured summary). The remaining reviews will be confirmed as eligible and data extracted by a single author. We will use descriptive statistics to summarise the specification of methods and their use in practice. We will compare how clearly the PICO for synthesis is specified in reviews that primarily use meta-analysis and those that do not.
CONCLUSION: This study will provide an understanding of current practice in two important aspects of the synthesis process, enabling future research to test the feasibility and impact of different approaches
Coating-Free Mirrors for Ultra-Sensitive Interferometry
Thermodynamical fluctuations impose random noise on the position of optical components.
It is predicted that this thermal noise will limit the sensitivity of interferometric
gravitational-wave detectors in their most sensitive frequency band. Thermal noise originating
from optical coatings was first considered in the context of interferometric gravitational
wave detectors. Its true significance was, however, only revealed after Y. Levin
introduced a new method in 1998 to calculate the resulting phase noise of a laser beam
reading out the position of a coated mirror. A result of this analysis is that the reflective
optical coatings introduce a particularly large portion of thermal noise.
¶
As a consequence, coating thermal noise is expected to prevent the detection of the
standard quantum limit; a limitation to the sensitivity of an interferometric measurement
caused by quantum fluctuations in the optical field. Elimination of the coating thermal
noise will increase the likelihood of the successful observation of the standard quantum
limit, thus enabling the investigation of quantum noise in the regime of optical squeezing.
This project investigated a means to eliminate the effects of coating thermal noise, with
the design and characterisation of a highly reflective coating-free mirror. This mirror
utilised the phenomenon of total internal reflection and the Brewster angle to reflect light
without the use of coatings. The dimensions of the mirror were governed by its expected
implementation in an experiment to measure the standard quantum limit.
¶
The design of the coating-free mirror undertaken as the initial part of this project is
presented in detail. Once a CFM had been created according to this design, its spatial
dimensions were measured. The weight of the mirror is 0.43 ± 0.01 g, well within the
design goal of 0.5 g.
¶
In order to analyse the reflectivity of the coating-free mirror it was incorporated, together
with a high quality conventional mirror, into a triangular ring cavity. This cavity was
stabilised to the laser frequency by the Pound-Drever-Hall technique. This enabled the
interrogation of the stable cavity properties by an AM-sideband transfer scheme. The
reflectivity of the mirror was analysed for optimum rotational alignment and as a function
of its rotational alignment angle. The maximum reflectivity deviated from the expected
value calculated from the mirror design. Most of the excess loss was attributed to scattering
due to surface roughness at the points of total internal reflection and a necessary
deviation from the Brewster angle due to the geometry of the cavity combined with the
flat front face of the coating free mirror.
¶
For optimum alignment a cavity finesse of about 4000 was measured, corresponding to a
reflectivity of the coating free mirror of 99.89%. Thus, the objective of creating a highly
reflective lightweight coating-free optic was achieved. The obtained reflectivity can be
further increased by using a substrate that is super polished at the faces of total internal
reflection
Calculation of single-beam two-photon absorption transition rate of rare-earth ions using effective operator and diagrammatic representation
Effective operators needed in single-beam two-photon transition calculations
have been represented with modified Goldstone diagrams similar to the type
suggested by Duan and co-workers [J. Chem. Phys. 121, 5071 (2004) ]. The rules
to evaluate these diagrams are different from those for effective Hamiltonian
and one-photon transition operators. It is verified that the perturbation terms
considered contain only connected diagrams and the evaluation rules are
simplified and given explicitly.Comment: 10 preprint pages, to appear in Journal of Alloys and Compound
Two-photon or higher-order absorbing optical materials for generation of reactive species
Disclosed are highly efficient multiphoton absorbing compounds and methods of their use. The compounds generally include a bridge of pi-conjugated bonds connecting electron donating groups or electron accepting groups. The bridge may be substituted with a variety of substituents as well. Solubility, lipophilicity, absorption maxima and other characteristics of the compounds may be tailored by changing the electron donating groups or electron accepting groups, the substituents attached to or the length of the pi-conjugated bridge. Numerous photophysical and photochemical methods are enabled by converting these compounds to electronically excited states upon simultaneous absorption of at least two photons of radiation. The compounds have large two-photon or higher-order absorptivities such that upon absorption, one or more Lewis acidic species, Lewis basic species, radical species or ionic species are formed
Critical elements of synthesis questions are incompletely reported: survey of systematic reviews of intervention effects
Objectives: To examine the characteristics of population, intervention and outcome groups and the extent to which they were completely reported for each synthesis in a sample of systematic reviews (SRs) of interventions. Study design and setting: We coded groups that were intended (or used) for comparisons in 100 randomly sampled SRs of public health and health systems interventions published in 2018 from the Health Evidence and Health Systems Evidence databases. Results: Authors commonly used population, intervention and outcome groups to structure comparisons, but these groups were often incompletely reported. For example, of 41 SRs that identified and/or used intervention groups for comparisons, 29 (71%) identified the groups in their methods description before reporting of the results (e.g., in the Background or Methods), 12 (29%) defined the groups in enough detail to replicate decisions about which included studies were eligible for each synthesis, 6 (15%) provided a rationale, and 24 (59%) stated that the groups would be used for comparisons. Sixteen (39%) SRs used intervention groups in their synthesis without any mention in the methods. Reporting for population, outcome and methodological groups was similarly incomplete. Conclusion: Complete reporting of the groups used for synthesis would improve transparency and replicability of reviews, and help ensure that the synthesis is not driven by what is reported in the included studies. Although concerted effort is needed to improve reporting, this should lead to more focused and useful reviews for decision-makers
- âŠ