177,627 research outputs found
Changing travel behaviour
No full textTSU:
The Transport Studies Unit, established
since 1973 at Oxford University, was
awarded the status of a designated
research centre of the ESRC from 1994 to
2004. The research programme, initially
focussed on traffic growth and the
development of dynamic methodologies,
was launched at a Linacre Lecture in
Oxford which attracted much press
attention for its comments on induced
traffic. The Unit transferred to University
College London in January 1996. After a
successful mid-term review, the second
five year programme focussed on the
process of behavioural change and
appraisal tools.
ESRC funding and designation came to an
end in September 2004 with an
exceptionally well-attended final event in
London on ‘Changing Travel Behaviour’,
which constituted a suitably unifying
theme bringing together a large proportion
of the Unit’s research projects.
Appreciations were given by many of the
leading stakeholders in transport policy
and research, with an audience of over 400
academics and practitioners.
Shortly after, the ESRC Transport Studies
Unit disbanded as an entity. The seven
researchers who had carried out the
programme are now continuing their
activities at six different locations in three
countries, though maintaining contact and
continuing to disseminate and extend the
results of the ten years work. Transport
research of course continues at both
Oxford University (TSU in the School of
Geography) and UCL (CTS in the
Department of Civil and Environmental
Engineering).
The ambiguity of ‘changing’:
The phrase ‘changing travel behaviour’ is
ambiguous – changing as a description of
what actually happens, and changing as an
active intent by public or private agencies.
The twin underlying propositions are that
travel behaviour does change, and by
understanding this travel behaviour can be
changed.
There is a third, implied statement, that
travel behaviour should be changed. This
goes beyond the research programme. All
three statements are controversial, but the
controversies are resolved by different
methods, from empirical and theoretical
analysis to public debate. All three
underpin the need to understand the
processes of behavioural change, and to
incorporate this understanding in the tools
for appraising both transport investment
and – as became apparent during the
period of the research – other transport
policies as well.
The logical structure used for this report
(in part developed retrospectively in the
course of planning for the TSU final
event) has five parts: (1) establish the
nature of the changes in travel behaviour
that have actually happened; (2) consider
the specific effects of two of the most
important general influences, namely
income, and demographic forces; (3)
2
consider the evidence on the effect of
transport policy, including both
investment and non-investment initiatives.
Those studied include new opportunities
such as park-and-ride, increases and
reductions in road capacity, increases and
reductions in public transport fares and
motoring costs, the effects of soft
measures such as travel plans and
information provision; (4) consider some
theoretical and practical understanding of
the nature of changes in behaviour; (5) discuss the policy implications of the wor
Hedging Effectiveness under Conditions of Asymmetry
No full textWe examine whether hedging effectiveness is affected by asymmetry in the return distribution by applying tail specific metrics to compare the hedging effectiveness of short and long hedgers using Oil futures contracts. The metrics used include Lower Partial Moments (LPM), Value at Risk (VaR) and Conditional Value at Risk (CVAR). Comparisons are applied to a number of hedging strategies including OLS and both Symmetric and Asymmetric GARCH models. Our findings show that asymmetry reduces in-sample hedging performance and that there are significant differences in hedging performance between short and long hedgers. Thus, tail specific performance metrics should be applied in evaluating hedging effectiveness. We also find that the Ordinary Least Squares (OLS) model provides consistently good performance across different measures of hedging effectiveness and estimation methods irrespective of the characteristics of the underlying distribution.Hedging Performance; Asymmetry; Downside Risk; Value at Risk, Conditional Value at Risk. JEL classification: G10, G12, G15. ____________________________________________________________________ John Cotter, Director of Centre for Financial Markets, Department of Banking and Finance, University College Dublin, Blackrock, Co. Dublin, Ireland, tel 353 1 716 8900, e-mail [email protected]. Jim Hanly, School of Accounting and Finance, Dublin Institute of Technology, tel 353 1 402 3180, e-mail [email protected]. The authors would like to thank the participants at the Global Finance Annual Conference for their constructive comments.
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Interference Cancellation in Groups
No full textIntroduction Consider a multi-user white noise channel of bandwidth W Hz, white noise spectral density j 2 , with M users all received at power P , all requiring the same rate R bits/sec. It is well known that that there is a Shannon capacity for the channel and that it is achievable by FDMA. It is well known that the capacity can also be achieved by an interference cancellation procedure that involves M 2 cancellations, and Rimoldi and Urbanke [3] have recently shown that it is achievable with at most 2M cancellation steps. In the present paper we show that we can achieve rates arbitrarily close to capacity with O(1) cancellation steps in the particular case of equal powers and equal rates. The results in the present paper first appeared in Hanly [1]. II. Interference cancellation It is well known that the equ
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Association between bile and acid turnover and osteoporosis in postmenopausal women
No full textObjective: The intestinal absorption of vitamin D is linked to bile acid absorption. This link may be abnormal in patients with osteoporosis. The aim of this study was to investigate a possible relation between osteoporosis and bile acid turnover, measured as whole-body Se-75-HCAT retention (WBR), in postmenopausal women.Patients and methods: Whole-body counts were recorded using an uncollimated gamma camera 3 h and 7 days after oral administration of Se-75-homocholic acid taurine (Se-75-HCAT) in 16 women aged 58-85 years with dual-photon X-ray absorptiometry (DEXA)-proven osteoporosis. WBR was expressed as physical decay-corrected counts at 7 days as a percentage of the counts at 3 h.Results: Seven patients had unexplained diarrhoea. Six patients (five with diarrhoea) had WBR less than 19%. There was a significant difference in DEXA t-score between women with and without diarrhoea (P<0.02). There was a significant negative correlation (R s=-0.58; P<0.02) between WBR and alcohol consumption rated on a three-point scale: <1, 2-7 and >7 U/week.Conclusion: Our results indicate an association between osteoporosis and diarrhoea that may be the result of abnormal bile acid turnover. The role of alcohol requires further investigation.<br/
Volatility of car ownership, commutingmode and time in the UK
No full textThis paper has two objectives: to examine the volatility of travel behaviour over timeand consider the factors explaining this volatility; and to estimate the factors determiningcar ownership and commuting by car. The analysis is based on observations of individualsand households over a period of up to eleven years obtained from the British HouseholdPanel Survey (BHPS). Changes in car ownership, commuting mode and commuting timeover a period of years for the same individuals/households are examined to determine theextent to which these change from year to year. This volatility of individual behaviour is ameasure of the ease of change or adaptation. If behaviour changes easily, policy measuresare likely to have a stronger and more rapid effect than if there is more resistance tochange. The changes are ?explained? in terms of factors such as moving house, changingjob and employment status. The factors determining car ownership and commuting by carare analysed using a dynamic panel-data models
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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