Good places for ageing in place : development of objective built environment measures for investigating links with older people's wellbeing

Background: There is renewed interest in the role of the built environment in public health. Relatively little research to date investigates its impact on healthy ageing. Ageing in place has been adopted as a key strategy for coping with the challenges of longevity. What is needed is a better understanding of how individual characteristics of older people’s residential environments (from front door to wider neighbourhood) contribute to their wellbeing, in order to provide the basis for evidence-based housing/urban design and development of interventions. This research aimed to develop a tool to objectively measure a large range of built environment characteristics, as the basis for a preliminary study of potential relationships with a number of ‘place-related’ functional, emotional and social wellbeing constructs. Methods: Through a review of urban design literature, design documents, and existing measures, a new tool, the NeDeCC (Neighbourhood Design Characteristics Checklist) was developed. It was piloted, refined, and its reliability validated through inter-rater tests. A range of place-related wellbeing constructs were identified and measured through interviews with 200 older people living in a wide variety of rural-urban environments and different types of housing in England. The NeDeCC was used to measure the residential environment of each participant, and significant bivariate relationships with wellbeing variables were identified. Results: The NeDeCC was found to have convincing face and construct validity and good inter-rater and test/ retest reliability, though it would benefit from use of digital data sources such as Google Earth to eliminate the need for on-site survey. The significant relationships found in the study suggest that there may be characteristics of residential environments of potential relevance for older people’s lives that have been overlooked in research to date, and that it may be worthwhile to question some of the assumptions about where and how older people want to live (e.g. villages seem to be positive). They also point to the importance of considering non-linear relationships. Conclusions: The NeDeCC provides the basis for generation of evidence-based design guidance if it is used in prospective controlled studies or ‘natural experiments’ in the future. Ultimately, this will facilitate the creation of better places for ageing in place

Essays on Capital Gains, Household Consumption and Corporate Payout Policy

My dissertation consists of three chapters related to accrued capital gains. The first essay is concerned with estimating the marginal propensity to consume (MPC) out of accrued capital gains on owner-occupied housing in Canada. Its main methodological contribution lies in using a hedonic price equation to value these gains. The results suggest that for every 1 dollar increase in expected housing capital gains households increase total consumption by approximately 8.2 cents, and increase non-durable consumption by 6.2 cents. The second essay of this thesis proposes a model of economic behaviour that can explain why corporations pay dividends despite their tax disadvantage relative to share repurchases. The key result is that firms must pay a premium above the intrinsic value of equity to repurchase shares, reflecting the lock-in effect caused by a realization-based capital gains tax system. In equilibrium, firms pay dividends whenever this additional cost is sufficiently high. The third essay examines the effect of capital income taxation on corporate payout policy in Canada. The analysis makes use of a new dataset on share repurchases carried out by Toronto Stock Exchange listed Canadian corporations over the period 1987-2008. It also uses new estimates of Canadian average marginal tax rates applied to capital income. The results suggest that total payout is positively related to changes in both the corporate income tax rate and the capital gains tax rate, but is unaffected by the dividend tax rate. The results also suggest that share repurchases are positively related to changes in the dividend tax rate and negatively related to changes in the capital gains tax rate. Dividends are found to have a positive relationship with capital gains tax changes

Security issues in a group key establishment protocol

Major shortcomings in a recently published group key establishment protocol are described. These shortcomings are sufficiently serious that the protocol should not be used.Comment: arXiv admin note: text overlap with arXiv:1803.0536

Analysing the IOBC Authenticated Encryption Mode

Abstract. The idea of combining a very simple form of added plaintext redundancy with a special mode of data encryption to provide data in-tegrity is an old one; however, despite its wide deployment in protocols such as Kerberos, it has largely been superseded by provably secure au-thenticated encryption techniques. In this paper we cryptanalyse a block cipher mode of operation called IOBC, possibly the only remaining en-cryption mode designed for such use that has not previously been ana-lyzed. We show that IOBC is subject to known-plaintext-based forgery attacks with a complexity of around 2n=3, where n is the block cipher block length.

Public key encryption using block ciphers

A method for deriving a public key encryption system from any `conventional' (secret key) block cipher is described. The method is related to, but improves upon, Merkle's 'puzzle system'

International standards for stream ciphers: a progress report

The main objective of this paper is to review the current status of stream cipher standardisation. The hope is that, by doing so, the algorithms and techniques that are likely to be standardised at some point during the next year or so will be subjected to rigorous scrutiny by the crytopgraphic community