27,993 research outputs found
Supporting strategy : a survey of UK OR/MS practitioners
This paper reports the results of an on-line survey conducted with practitioner members of the UK Operational Research (OR) Society. The purpose of the survey was to explore the current practice of supporting strategy in terms of activities supported and tools used. The results of the survey are compared to those of previous surveys to explore developments in, inter-alia, the use of management/strategy tools and āsoftā Operational Research / Management Science (OR/MS) tools. The survey results demonstrate that OR practitioners actively support strategy within their organisations. Whilst a wide variety of tools, drawn from the OR/MS and management / strategy fields are used to support strategy within organisations, the findings suggest that soft OR/MS tools are not regularly used. The findings also demonstrate that tools are combined to support strategy from both within and across the OR/MS and management / strategy fields. The paper ends by identifying a number of areas for further research
Union learning representatives: facilitating professional development for Scottish teachers
In the United Kingdom, teachers' professional associations and labor organizations, notably in the form of trade unions have historically been involved in education and training in the workplace. Recently, in the United Kingdom this activity has gained greater credence and importance due to the emergence of trade union learning representatives who are a new category of unpaid lay representation with statutory rights who operate within the workplace. They are part of the present UK government's drive to expand and improve lifelong learning and continuing professional development (CPD) in order to create the new learning society within the UK. In Scotland, a constituent part of the UK with its own distinctive education system, the McCrone Report (2000), particularly its CPD recommendations and the subsequent 21st Century Agreement (Scottish Executive Education Department [SEED], 2001) has added impetus to the role of these learning representatives within the Scottish teaching profession. This article examines how the Educational Institute of Scotland, a professional trade union, which represents the overwhelming majority of teachers in Scotland, has launched a learning representatives initiative with the aim that the representatives work to advise, broker, and facilitate improved CPD opportunities for their colleagues, particularly in relation to Chartered Teacher status (O'Brien and Hunt, 2005)
Code loops in dimension at most 8
Code loops are certain Moufang -loops constructed from doubly even binary
codes that play an important role in the construction of local subgroups of
sporadic groups. More precisely, code loops are central extensions of the group
of order by an elementary abelian -group in the variety of loops
such that their squaring map, commutator map and associator map are related by
combinatorial polarization and the associator map is a trilinear alternating
form.
Using existing classifications of trilinear alternating forms over the field
of elements, we enumerate code loops of dimension
(equivalently, of order ) up to isomorphism. There are
code loops of order , and of order , and of order
A note on the estimation of confidence intervals for cost-effectiveness when costs and effects are censored
<i>Background</i>. The relation between methodological advances in estimation of confidence intervals (CIs) for incremental cost-effectiveness ratios (ICER) and estimation of cost effectiveness in the presence of censoring has not been explored. The authors address the joint problem of estimating ICER precision in the presence of censoring.
<i>Methods</i>. Using patient-level data (n = 168) on cost and survival from a published placebo-controlled trial, the authors compared 2 methods of measuring uncertainty with censored data: 1)Bootstrap with censor adjustment (BCA); 2) Fiellerās method with censor adjustment (FCA). The authors estimate the FCA over all possible values for the correlation (p) between costs and effects (range= ā1 to +1) and also examine the use of the correlation between cases without censoring adjustment (i.e., simple time-on-study) for costs and effects as an approximation for.
<i>Results</i>. Using time-on-study, which considers all
censored observations as responders (deaths), yields 0.64
life-years gained at an additional cost of 87.9 for a cost per life-year of 137 (95% CI by bootstrap ā5.9 to 392). Censoring adjustment corrects for the bias in the time-on-study approach and reduces the cost per life-year estimate to 132 (=72/0.54). Confidence intervals with censor adjustment were approximately 40% wider than the base-case without adjustment. Using the Fieller method with an approximation of based on the uncensored cost and effect correlation provides a 95% CI of (ā48 to 529), which is very close to the BCA interval of (ā52 to 504).
<i>Conclusions</i>. Adjustment for censoring is necessary in cost-effectiveness studies to obtain unbiased estimates of ICER with appropriate uncertainty limits. In this study, BCA and FCA methods, the latter with approximated covariance, are simple to compute and give similar confidence intervals
Surface Free Energies, Interfacial Tensions and Correlation Lengths of the ABF Models
The surface free energies, interfacial tensions and correlation lengths of
the Andrews-Baxter-Forrester models in regimes III and IV are calculated with
fixed boundary conditions. The interfacial tensions are calculated between
arbitrary phases and are shown to be additive. The associated critical
exponents are given by with in regime III
and with in regime IV. Our results are
obtained using general commuting transfer matrix and inversion relation methods
that may be applied to other solvable lattice models.Comment: 21 pages, LaTeX 2e, requires the amsmath packag
Shor's quantum factoring algorithm on a photonic chip
Shor's quantum factoring algorithm finds the prime factors of a large number
exponentially faster than any other known method a task that lies at the heart
of modern information security, particularly on the internet. This algorithm
requires a quantum computer a device which harnesses the `massive parallelism'
afforded by quantum superposition and entanglement of quantum bits (or qubits).
We report the demonstration of a compiled version of Shor's algorithm on an
integrated waveguide silica-on-silicon chip that guides four single-photon
qubits through the computation to factor 15.Comment: 2 pages, 1 figur
Cost-effectiveness acceptability curves - facts, fallacies and frequently asked questions
Cost-effectiveness acceptability curves (CEACs) have been widely adopted as a method to quantify and graphically represent uncertainty in economic evaluation studies of health-care technologies. However, there remain some common fallacies regarding the nature and shape of CEACs that largely result from the textbook illustration of the CEAC. This textbook CEAC shows a smooth curve starting at probability 0, with an asymptote to 1 for higher money values of the health outcome (). But this familiar ogive shape which makes the textbook CEAC look like a cumulative distribution function is just one special case of the CEAC. The reality is that the CEAC can take many shapes and turns because it is a graphic transformation from the cost-effectiveness plane, where the joint density of incremental costs and effects may straddle quadrants with attendant discontinuities and asymptotes. In fact CEACs: (i) do not have to cut the y-axis at 0; (ii) do not have to asymptote to 1; (iii) are not always monotonically increasing in ; and (iv) do not represent cumulative distribution functions (cdfs). Within this paper we present a gallery of CEACs in order to identify the fallacies and illustrate the facts surrounding the CEAC. The aim of the paper is to serve as a reference tool to accompany the increased use of CEACs within major medical journals
Recognition of finite exceptional groups of Lie type
Let be a prime power and let be an absolutely irreducible subgroup of
, where is a finite field of the same characteristic as \F_q,
the field of elements. Assume that , a quasisimple group of
exceptional Lie type over \F_q which is neither a Suzuki nor a Ree group. We
present a Las Vegas algorithm that constructs an isomorphism from to the
standard copy of . If with even, then the
algorithm runs in polynomial time, subject to the existence of a discrete log
oracle
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