Stephen McDonald

Informative Brand Advertising and Pricing Strategies in Internet Markets with Heterogeneous Consumer Search

Abstract The use of information intermediaries has been shown to undermine the effect of brand in online markets. In this paper, the effect of consumer search on the relationship between brand advertising and pricing strategies is analysed. Price data are taken from the leading UK motor insurance comparison website, with the advantage that prices can be related to the search characteristics of consumers and to the advertising expenditure of firms. The paper finds that more-advertised firms have lower price rankings at the comparison site, indicating that advertising is informative in this market. The main result is that consumer search weakens the relationship between advertising and pricing. An implication is that increased usage of price comparison sites will make informative brand advertising less important.

Effects of frequency deviation on the accuracy of harmonic analysis and mitigation

Different signal processing techniques are available for automatic detection and diagnosis of power quality disturbances. This paper describes the results of a comparison of the effects of frequency deviation on the accuracy of a number of widely used techniques for signal harmonic analysis, together with a means of mitigation of these effects.

Consumer Search Ability, Price Dispersion and the Digital Divide†

The ‘digital divide’ in online activities is believed to arise from differences in Internet access, but this paper advances an alternative explanation that is related to consumer search ability. It argues that this leads to greater price dispersion, causing some consumers to be discriminated against. It analyses price data for the UK Internet motor insurance market, collecting data on 32,255 prices for 110 sub-markets, where differences in price dispersion across these by age, occupation and sex of the driver are argued to reflect differences in search ability. Allowing for price dispersion to also depend on the insurance risk, it finds greater price dispersion for consumers with weaker search abilities, i.e. older, unemployed, retired or female consumers. As this is not explained by alternative hypotheses, the paper concludes that improved Internet access alone will not close the ‘digital divide’. The implication is that policymakers should address the online search abilities of individuals as well as Internet access.

Overcoming the challenges of “drag torque” in a dual-lane actuator for an aircraft

Actuators for the more electric aircraft are predominantly based on permanent magnet machines to achieve the optimum power to weight ratio. High reliability of these actuators is important and typically this results in the adoption of a dual-lane multiphase topology. This is to provide redundancy in both the power electronics and the machine so as to achieve the desired reliability. However, in fault conditions, it is possible for the drag torque caused by a short-circuited phase of a permanent magnet machine to be sufficiently large that the rating of the healthy lane needs to be significantly overrated to ensure it can meet the operational specification. This effectively negates the advantages of the machine to some degree. Segmental Rotor Switched Reluctance machines have been demonstrated to provide enhanced performance compared with conventional Switched Reluctance machines and have the potential to overcome this problem of drag torque in a faulted lane whilst maintaining the necessary power to weight requirements. This paper explores some of the challenges involved in the design and realization of a novel motor and drive solution suitable for a fault tolerant aerospace nose-wheel actuator. For example, the actuator under investigation has a very short stack length resulting in significant end-winding effects. By introducing small sections of permanent magnet material between the stator teeth the performance of the machine can be improved even further, thus mitigating these end-winding effects. Design considerations and simulation results are presented with a narrative of our development program to date.

Multibrand pricing as a strategy for consumer search obfuscation in online markets

This paper argues that a firm with multiple brands can obfuscate consumer search by excluding the brands of other firms from a consumers consideration set. This is examined empirically by regressing price data for a leading U.K. motor insurance price comparison site (or “shopbot†). It finds that multibrand firms own three†quarters of brands in this market, and that allowing for other brand strategies, they post significantly lower and clustered prices relative to other firms. The firms also conceal their brand ownership, consistent with search obfuscation. The results are not otherwise explained and they have implications for market competitiveness.

A permanent magnet assisted switched reluctance machine for more electric aircraft

Actuators for more electric aircraft are predominantly based on permanent magnet machines for the best power to weight ratio. However, permanent magnet machines can give rise to drag torque under short circuit conditions. This paper explains the concept of permanent magnet assistance in switched reluctance machines and sets out a topology which maximizes the benefits of permanent magnet assistance without compromising fault tolerance. The problem of demagnetization in this topology is explored and a revised design proposed. The increased torque from permanent magnet assistance is demonstrated, and laboratory tests on a prototype machine evidence the fault tolerant nature of the proposed machine by comparison with a baseline permanent magnet machine design. It is suggested that the permanent magnet assisted segmental rotor switched reluctance machine could achieve similar torque to a permanent magnet machine in this application with much improved fault tolerance and with much reduced magnet mass.