Model sensitivity and uncertainty analysis using roadside air quality measurements

Most of the air quality modelling work has been so far oriented towards deterministic simulations of ambient pollutant concentrations. This traditional approach, which is based on the use of one selected model and one data set of discrete input values, does not reflect the uncertainties due to errors in model formulation and input data. Given the complexities of urban environments and the inherent limitations of mathematical modelling, it is unlikely that a single model based on routinely available meteorological and emission data will give satisfactory short-term predictions. In this study, different methods involving the use of more than one dispersion model, in association with different emission simulation methodologies and meteorological data sets, were explored for predicting best CO and benzene estimates, and related confidence bounds. The different approaches were tested using experimental data obtained during intensive monitoring campaigns in busy street canyons in Paris, France. Three relative simple dispersion models (STREET, OSPM and AEOLIUS) that are likely to be used for regulatory purposes were selected for this application. A sensitivity analysis was conducted in order to identify internal model parameters that might significantly affect results. Finally, a probabilistic methodology for assessing urban air quality was proposed.

Numerical experiments of some Krylov subspace methods for black oil model

This paper discusses preconditioned Krylov subspace methods for solving large scale linear systems that originate from oil reservoir numerical simulations. Two types of preconditioners, one being based on an incomplete LU decomposition and the other being based on iterative algorithms, are used together in a combination strategy in order to achieve an adaptive and efficient preconditioner. Numerical tests show that different Krylov subspace methods combining with appropriate preconditioners are able to achieve optimal performance.

Uncertainty analysis to minimise risk in designing micro-electronics manufacturing processes

A design methodology based on numerical modelling, integrated with optimisation techniques and statistical methods, to aid the process control of micro and nano-electronics based manufacturing processes is presented in this paper. The design methodology is demonstrated for a micro-machining process called Focused Ion Beam (FIB). This process has been modelled to help understand how a pre-defined geometry of micro- and nano- structures can be achieved using this technology. The process performance is characterised on the basis of developed Reduced Order Models (ROM) and are generated using results from a mathematical model of the Focused Ion Beam and Design of Experiment (DoE) methods. Two ion beam sources, Argon and Gallium ions, have been used to compare and quantify the process variable uncertainties that can be observed during the milling process. The evaluations of the process performance takes into account the uncertainties and variations of the process variables and are used to identify their impact on the reliability and quality of the fabricated structure. An optimisation based design task is to identify the optimal process conditions, by varying the process variables, so that certain quality objectives and requirements are achieved and imposed constraints are satisfied. The software tools used and developed to demonstrate the design methodology are also presented.

Paying the price for loss of light

Considers the Court of Appeal ruling in Forsyth-Grant v Allen on the principles to be applied in assessing damages for the loss of light. Outlines the method for calculating damages for loss of right to light, the type of amenity which will be included in calculations for loss of amenity and the process applied in this case for assessing damages arising from the loss of profits that would have been made by the owner of the right to light if they had negotiated to relax the covenant, with reference to case law. Notes the limits to damages available for hypothetical loss and the difference between this award of profits and an account of profits.

A price worth paying?: Women and work – choice, constraint or satisficing

Purpose – Are women held back or holding back? Do women choose their jobs/careers or are they structurally or normatively constrained? The purpose of this paper is to shed fresh light on these questions and contribute to an on-going debate that has essentially focused on the extent to which part-time work is women’s choice, the role of structural and organisational constraints and the role of men in excluding women. Design/methodology/approach – The paper uses data from interviews with 80 working women – both full-time and part-time – performing diverse work roles in a range of organisations in the south east of England. Findings – It was found that many women do not make strategic job choices, rather they often ‘‘fall into’’ jobs that happen to be available to them. Some would not have aspired to their present jobs without male encouragement; many report incidents of male exclusion; and virtually all either know or suspect that they are paid less than comparable men. Those working reduced hours enjoy that facility, yet they are aware that reduced hours and senior roles are seen as incompatible. In short, they recognise both the positive and negative aspects of their jobs, whether they work full or part-time, whether they work in male-dominated or female-dominated occupations, and whatever their position in the organisational hierarchy. Accordingly, the paper argues that the concept of ‘‘satisficing’’, i.e. a decision which is good enough but not optimal, is a more appropriate way to view women’s working lives than are either choice or constraint theories. Originality/value – There is an ongoing, and often polarised, debate between those who maintain that women choose whether to give preference to work or home/family and others who maintain that women, far from being self-determining actors, are constrained structurally and normatively. Rather than supporting these choice or constraint theories, this paper argues that ‘‘satisficing’’ is a more appropriate and nuanced concept to explain women’s working lives.

Memorandum submitted by the University of Greenwich: are the consumer price increases for electricity imposed in January 2008 justified?

This paper examines whether increases to published wholesale prices justify the retail electricity price increases imposed on residential consumers in January 2008. The study is based on analysis of two questions: Is the reported wholesale price a reliable indicator of the cost electricity retailers are paying to buy power; and is the corporate structure of the British electricity sector competitive? [Taken from first paragraph of summary]

The determinants of business performance of estate agency in England and Wales

Purpose: This paper seeks to investigate the factors influencing the business performance of estate agency in England and Wales. Design/methodology/approach: The paper investigates the effect of housing market, company size and pricing policy on business performance in the estate agency sector in England and Wales. The analysis uses the survey data of Woolwich Cost of Moving Survey (a survey of transactions costs sponsored by the Woolwich/Barclays Bank) from 2003 to 2005 to test the hypothesis that the business performance of estate agency is affected by industry characteristics and firm factors. Findings: The empirical analysis indicates that the business performance of estate agency is subject to market environment volatility such as market uncertainty, housing market liquidity and house price changes. The firm factors such as firm size and the level of agency fee have no explanatory power in explaining business performance. The level of agency fee is positively associated with firm size, market environment and liquidity. Research limitations/implications: The research is limited to the data received and is based on a research project on transaction costs designed prior to this analysis. Originality/value: There is little other research that investigates the factors determining the business performance of estate agency, using consecutive data of three years across England and Wales. The findings are useful for practitioners and/or managers to allocate resources and adjust their business strategy to enhance business performance in the estate agency sector.