COOPER-framework: A Unified Standard Process for Non-parametric Projects

Practitioners assess performance of entities in increasingly large and complicated datasets. If non-parametric models, such as Data Envelopment Analysis, were ever considered as simple push-button technologies, this is impossible when many variables are available or when data have to be compiled from several sources. This paper introduces by the ‘COOPER-framework’ a comprehensive model for carrying out non-parametric projects. The framework consists of six interrelated phases: Concepts and objectives, On structuring data, Operational models, Performance comparison model, Evaluation, and Result and deployment. Each of the phases describes some necessary steps a researcher should examine for a well defined and repeatable analysis. The COOPER-framework provides for the novice analyst guidance, structure and advice for a sound non-parametric analysis. The more experienced analyst benefits from a check list such that important issues are not forgotten. In addition, by the use of a standardized framework non-parametric assessments will be more reliable, more repeatable, more manageable, faster and less costly.DEA, non-parametric efficiency, unified standard process, COOPER-framework.

Prediction of heat transfer from laminar boundary layers, with emphasis on large free- stream velocity gradients and highly cooled walls

Prediction of heat transfer and shear stress from laminar boundary laye

A Penalty Method for the Numerical Solution of Hamilton-Jacobi-Bellman (HJB) Equations in Finance

We present a simple and easy to implement method for the numerical solution of a rather general class of Hamilton-Jacobi-Bellman (HJB) equations. In many cases, the considered problems have only a viscosity solution, to which, fortunately, many intuitive (e.g. finite difference based) discretisations can be shown to converge. However, especially when using fully implicit time stepping schemes with their desirable stability properties, one is still faced with the considerable task of solving the resulting nonlinear discrete system. In this paper, we introduce a penalty method which approximates the nonlinear discrete system to first order in the penalty parameter, and we show that an iterative scheme can be used to solve the penalised discrete problem in finitely many steps. We include a number of examples from mathematical finance for which the described approach yields a rigorous numerical scheme and present numerical results.Comment: 18 Pages, 4 Figures. This updated version has a slightly more detailed introduction. In the current form, the paper will appear in SIAM Journal on Numerical Analysi

Detecting the Stimulated Decay of Axions at Radio Frequencies

Assuming axion-like particles account for the entirety of the dark matter in the Universe, we study the possibility of detecting their decay into photons at radio frequencies. We discuss different astrophysical targets, such as dwarf spheroidal galaxies, the Galactic Center and halo, and galaxy clusters. The presence of an ambient radiation field leads to a stimulated enhancement of the decay rate; depending on the environment and the mass of the axion, the effect of stimulated emission may amplify the photon flux by serval orders of magnitude. For axion-photon couplings allowed by astrophysical and laboratory constraints(and possibly favored by stellar cooling), we find the signal to be within the reach of next-generation radio telescopes such as the Square Kilometer Array.Comment: Minor changes, references added, matches published versio

Prospective study of coffee and tea consumption in relation to risk of type 2 diabetes mellitus among men and women: The Whitehall II study

At least fourteen cohort studies have documented all inverse association between coffee consumption and risk of type 2 diabetes. We examined the prospective association between coffee and tea consumption and the risk of type 2 diabetes mellitus among British men (n 4055) and women (n 1768) from the Whitehall II cohort. During 11.7 years follow-up there were a total of 387 incident cases of diabetes confirmed by Self-report of doctor's diagnosis or glucose tolerance tests. Despite an inverse association between coffee intake and 2 h post-load glucose concentration at the baseline assessment, combined caffeinated and decaffeinated coffee (hazard ratio (HR) 0-80 95% CI 0.54, 1.18) or only decaffeinated coffee intake (HR 0.65: 95% CI 0.36, 1.16) was not significantly associated with diabetes risk at follow-up after adjustment for possible confounders. There was all association between tea intake and diabetes (HR 0.66: 95% CI 0.61, 1.22: P<0.05) after adjustment for age. gender. ethnicity and social status, which was not robust to further adjustments. There was. however, an association between combined intake of tea and coffee (two or more cups per clay of both beverage) and diabetes (HR 0.68: 95% CI 0.46, 0.99: P<0.05) after full adjustment. In conclusion, relatively moderate intake (more than three CLIPS per (lay) of coffee and tea were not prospectively associated with incidence of type 2 diabetes although there was evidence of a combined effect. The limited range of exposure and beverage consumption according to socio-economic class may explain these conflicting findings

‘Documentary filmmakers and their ethical decisions’

This study aims to gain more insight into the experiences of Dutch documentary makers working with subjects under the circumstances of inequality between the two parties and how, from this position of a power imbalance, the topic of representation is approached. In scrutinizing the experiences of these documentary makers, this research seeks to understand what these experiences mean in terms of ethical decision making processes in media and how they link to underlying values and motivations connected to meaning making (in media making). The inequality of power, through the power held by the documentary maker because of the possession of a camera (and crew), is inherent to the relationship between filmmaker and subject. Apart from this, all ten documentary makers who are part of this explorative, qualitative research have experience working with subjects who have either refugee status or background; or worked with a subject with a non-western background in a situation of (economical) exploitation and/or oppression, creating a socio-economic or socio-politic inequality. Because of these inequalities, documentary filmmakers are confronted with ethical problems and ethical dilemmas in their work at a much higher rate than other professions. Another factor that is also considered in this research is the representation of the subject. There is little qualitative research on documentary ethics based on the experience of the documentary makers concerning their relationship with their subjects. Between the professionals, there is no habit of (informally) discussing their experiences, but instead most decision making processes are based on internal, ‘intuition’-based processes. This research found similarities and differences between the documentary makers’ ethical stances, motivations and aspirations as well as possible approaches that show how documentary makers handle inequality and representation of their subjects. The most poignant approach on how to counteract inequality is to find some form of ‘exchange’, which was experienced and used in terms of taking (from the subject) and giving (to the subject). Others found a way to incorporate their subjects into the making of the film, which also decreased inequality and had positive effects on representation