The British Accounting Review - characteristics of papers submitted and accepted, 1997 to 2006

Abstract not available

Design of a multivariable integrated control for a supersonic propulsion system

An inlet/engine/nozzle integrated control mode for the propulsion system of an advanced supersonic commercial aircraft was studied. Results show that integration of these control functions can result in both operational and performance benefits for the propulsion system. For example, this integrated control mode may make it possible to minimize the use of inlet bypass doors for shock position control. This may be of benefit to the aircraft as a result of minimizing: (1) bypass bleed drag effects; (2) perturbations to the aircraft resulting from the side thrust effect of the bypass bleeds; and (3) potential unstarts of the inlet. A conceptual integrated control mode was developed which makes use of many cross coupling paths between inlet and engine control variables and inlet and engine sensed variables. A multivariable control design technique based upon linear quadratic regulator theory was applied to designing the feedback gains for this control to allow a simulation evaluation of the benefits of the integrated control mode

Preliminary study, analysis and design for a power switch for digital engine actuators

Innovative control configurations using high temperature switches to operate actuator driving solenoids were studied. The impact on engine control system life cycle costs and reliability of electronic control and (ECU) heat dissipation due to power conditioning and interface drivers were addressed. Various power supply and actuation schemes were investigated, including optical signal transmission and electronics on the actuator, engine driven alternator, and inside the ECU. The use of a switching shunt power conditioner results in the most significant decrease in heat dissipation within the ECU. No overall control system reliability improvement is projected by the use of remote high temperature switches for solenoid drivers

Interpolatory Weighted-H2 Model Reduction

This paper introduces an interpolation framework for the weighted-H2 model reduction problem. We obtain a new representation of the weighted-H2 norm of SISO systems that provides new interpolatory first order necessary conditions for an optimal reduced-order model. The H2 norm representation also provides an error expression that motivates a new weighted-H2 model reduction algorithm. Several numerical examples illustrate the effectiveness of the proposed approach

PRODUCT COMPLEMENTARITY IN PRODUCTION: THE BY-PRODUCT CASE

Production Economics,

Studies on the biology of the common frog rana temporaria temporaria (linnaeus) with particular reference to altitude

Aspects of tile breeding biology of the Common Frog, Rana temporaria temporaria L., were studied in relation to altitude. Work centred on 55 breeding ponds in northern England, ranging in altitude from 86 to 838m. A chemical temperature integration technique was used to measure pond and soil temperatures at a series of sites. The temperature fell by approximately 0.4 C for every l00m increase in altitude. Between 1974 and 1977 spawning was always later at higher altitudes. By delaying spawning, highland embryos were less likely to encounter lethally low temperatures. Highland female frogs were about five per cent smaller in snout-vent length than lowland females and produced 707 eggs on average, less than half the mean number of 1,586 eggs produced by lowland frogs. These differences were thought to be due to the short growing season and possibly to the lack of food at higher altitudes. At 6 C the eggs from highland females developed four per cent faster than those from lowland females. Highland eggs had a lower lethal limit for normal development of 2.8 C; one Celsius degree below the limit for lowland eggs. The mucopolysaccharide capsules covering the eggs of Common Frogs act as insulators, keeping the embryos warmer on average than the surrounding water. This is thought to be of importance as Common Frogs breed early in the year when pond temperatures are often close to the lower lethal limit. The volume of the capsules and their insulating efficiency varied in different pond waters. The concentration of the ions in the pond water used as the culture medium was found to be the major factor influencing capsular swelling, but the valency of the ions, the temperature and pH of the water were also important. These findings were discussed in terms of their adaptive significance

And then there were four: a study of UK market concentration - causes, consequences and the scope for market adjustment

While concentration measures are a good indicator of market structure, the link with competitiveness is more complex than often assumed. In particular, the modern theory of industrial organisation makes no clear statement regarding the impact of concentration on competition - the focus of this paper is concentration and no inferences are made about competitive aspects of the market. The extent and nature of concentration within the UK listed company audit market as at April, 2002 and, pro forma, after the collapse of Andersen is documented and analysed in detail (by firm, market segment and industry sector). The largest four firms held 90 per cent of the market (based on audit fees) in 2002, rising to 96 per cent with the demise of Andersen. A single firm, Pricewaterhouse-Coopers, held 70 per cent or more of the share of six out of 38 industry sectors, with a share of 50 per cent up to 70 per cent in a further seven sectors. The provision of non-audit services (NAS) by incumbent auditors is also considered. As at April 2002, the average ratio of non-audit fees (paid to auditor) to audit fees was 208 per cent, and exceeded 300 per cent in seven sectors. It is likely, however, that disposals by firms of their management consultancy and outsource firms, combined with the impact of the Smith Report on audit committees will serve to reduce these ratios. Another finding is that audit firms with expertise in a particular sector appeared to earn significantly higher nonaudit fees from their audit clients in that sector. The paper thus provides a solid empirical basis for debate. The subsequent discussion considers the implications for companies and audit firms of the high level of concentration in the current regulatory climate, where no direct regulatory intervention is planned

Oxidative Heck desymmetrisation of 2,2-disubstituted cyclopentene-1,3-diones

Oxidative Heck couplings have been successfully developed for 2,2-disubstituted cyclopentene-1,3-diones. The direct coupling onto the 2,2-disubstituted cyclopentene-1,3-dione core provides a novel expedient way of enantioselectively desymmetrising all-carbon quaternary centres