Improving estimates of the number of fake leptons and other mis-reconstructed objects in hadron collider events: BoB's your UNCLE. (Previously "The Matrix Method Reloaded")

We consider current and alternative approaches to setting limits on new physics signals having backgrounds from misidentified objects; for example jets misidentified as leptons, b-jets or photons. Many ATLAS and CMS analyses have used a heuristic matrix method for estimating the background contribution from such sources. We demonstrate that the matrix method suffers from statistical shortcomings that can adversely affect its ability to set robust limits. A rigorous alternative method is discussed, and is seen to produce fake rate estimates and limits with better qualities, but is found to be too costly to use. Having investigated the nature of the approximations used to derive the matrix method, we propose a third strategy that is seen to marry the speed of the matrix method to the performance and physicality of the more rigorous approach.Comment: v1 :11 pages, 5 figures. v2: title change requested by referee, and other corrections/clarifications found during review. v3: final tweaks suggested during review + move from revtex to jhep styl

A finite difference solution for the propagation of sound in near sonic flows

An explicit time/space finite difference procedure is used to model the propagation of sound in a quasi one-dimensional duct containing high Mach number subsonic flow. Nonlinear acoustic equations are derived by perturbing the time-dependent Euler equations about a steady, compressible mean flow. The governing difference relations are based on a fourth-order, two-step (predictor-corrector) MacCormack scheme. The solution algorithm functions by switching on a time harmonic source and allowing the difference equations to iterate to a steady state. The principal effect of the non-linearities was to shift acoustical energy to higher harmonics. With increased source strengths, wave steepening was observed. This phenomenon suggests that the acoustical response may approach a shock behavior at at higher sound pressure level as the throat Mach number aproaches unity. On a peak level basis, good agreement between the nonlinear finite difference and linear finite element solutions was observed, even through a peak sound pressure level of about 150 dB occurred in the throat region. Nonlinear steady state waveform solutions are shown to be in excellent agreement with a nonlinear asymptotic theory

POPCORN: a Supervisory Control Simulation for Workload and Performance Research

A multi-task simulation of a semi-automatic supervisory control system was developed to provide an environment in which training, operator strategy development, failure detection and resolution, levels of automation, and operator workload can be investigated. The goal was to develop a well-defined, but realistically complex, task that would lend itself to model-based analysis. The name of the task (POPCORN) reflects the visual display that depicts different task elements milling around waiting to be released and pop out to be performed. The operator's task was to complete each of 100 task elements that ere represented by different symbols, by selecting a target task and entering the desired a command. The simulated automatic system then completed the selected function automatically. Highly significant differences in performance, strategy, and rated workload were found as a function of all experimental manipulations (except reward/penalty)

On Balazard, Saias, and Yor's equivalence to the Riemann Hypothesis

Balazard, Saias, and Yor proved that the Riemann Hypothesis is equivalent to a certain weighted integral of the logarithm of the Riemann zeta-function along the critical line equaling zero. Assuming the Riemann Hypothesis, we investigate the rate at which a truncated version of this integral tends to zero, answering a question of Borwein, Bradley, and Crandall and disproving a conjecture of the same authors. A simple modification of our techniques gives a new proof of a classical Omega theorem for the function S(t) in the theory of the Riemann zeta-function.Comment: 11 page

Creating structure from disorder: using folksonomies to create semantic metadata

This paper reports on an on-going research project to create educational semantic metadata out of folksonomies. The paper describes a simple scenario for the usage of the generated semantic metadata in teaching, and describes the ‘FolksAnnotation’ tool which applies an organization scheme to tags in a specific domain of interest. The contribution of this paper is to describe an evaluation framework which will allow us to validate our claim that folksonomies are potentially a rich source of metadata

Towards an integrated approach to the recognition of professional competence and academic learning

Purpose – The purpose of this paper is to discuss the benefits of reclaiming the idea of professional competence and challenges fragmented approaches to academic qualification and professional recognition. It is argued that academic programmes that are integrated with the requirements for professional recognition can resolve the potentially unhelpful differentiation between “theory” and “practice” and between “knowledge” and “competence”. Design/methodology/approach – Three contextualised case studies are presented to demonstrate a range of possibilities for developing academic programmes that integrate professional competence in the fields of construction, aviation and management. Findings – It is argued that the examples described provide some evidence that where competence is conceived of as a matter of open on-going professional development, it can be effectively integrated and aligned with the intended outcomes of academic qualifications. Furthermore, that the examples described demonstrate that the idea of professional competence can operate to ground knowledge in practice contexts and ensure that professional values are positioned as a requirement of being qualified. Originality/value – The diversity of the examples provided across three distinct sectors illustrate the potential for wider curriculum development opportunities for higher education practitioners. The need to align professional body recognition with academic qualification for higher and degree apprenticeships may also indicate significant implications for policy in this area. The cases presented provide evidence that academic qualifications can be developed that are at the same time recognised by employers as delivering a professionally competent workforce. This kind of development activity can provide both an incentive for employers to pay for education and training and opening opportunities for career progression for those in work

On the variance of sums of divisor functions in short intervals

© 2016 American Mathematical Society. Given a positive integer n the k-fold divisor function dk(n) equals the number of ordered k-tuples of positive integers whose product equals n. In this article we study the variance of sums of dk(n) in short intervals and establish asymptotic formulas for the variance of sums of dk(n) in short intervals of certain lengths for k = 3 and for k ≥ 4 under the assumption of the Lindelöf hypothesis