449 research outputs found

    A cell-based logit-opportunity taxi customer-search model

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    This paper proposes a cell-based model to predict local customer-search movements of vacant taxi drivers, which incorporates the modeling principles of the logit-based search model and the intervening opportunity model. The local customer-search movements were extracted from the global positioning system data of 460 Hong Kong urban taxis and inputted into a cell-based taxi operating network to calibrate the model and validate the modeling concepts. The model results reveal that the taxi driversā€™ local search decisions are significantly affected by the (cumulative) probability of successfully picking up a customer along the search route, and that the drivers do not search their customers under the random walk principle. The proposed model helps predict the effects of the implementation of the policies in adjusting the taxi fleet size and the changes in passenger demand on the customer-search distance and time of taxi drivers

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    Balancing the peak and off-peak travel demands towards cemeteries and columbaria

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    Special events attract extraordinarily high travel demands within a relative short period of time. Managing those travel demands is more critical than that for normal commuting trips since the high demands usually induce more severe impacts to local traffic. The impacts vary amongst different special events due to the difference in their natures. Unlike most of the special events like concerts or football matches that have a fixed date and time, the visitors to grave-sweeping could choose their available date and time to visit around the festival dates. Therefore, the policy measures suggested to manage the demand for other special events in the previous researches ...postprin

    Sequential Logit Approach to Modeling Customer-searching Decisions of Taxi Drivers

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    Fulltext link: http://easts.info/on-line/proceedings/vol9/PDF/P137.pdfThis paper develops an enhanced sequential logit model to depict the customer-search behavior of vacant-taxi drivers. This model considers that vacant-taxi drivers can change the choices they make on their way to a designated district. Trip data from the global positioning systems (GPSs) of 460 urban taxis were extracted to calibrate the model and verify the factors underlying the driversā€™ search decisions. The findings reveal that the proposed sequential logit model is capable of predicting the search paths of vacant-taxi drivers. This model form is considered more informative for policymakers who aim to study search paths and the associated traffic congestion contributed by taxis in each district

    Mixed logit approach to modelling arrival time choice behaviour of cemetery and columbarium visitors during grave-sweeping festivals

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    Special events attract extraordinarily high travel demands over a relatively short time. Managing the travel demand for special events is more difficult than for normal commuting trips. Grave-sweeping is a special event that is popular in Asia, especially in Chinese societies. In Hong Kong, many people visit cemeteries and columbaria around the two traditional festivals, causing overcrowding at the sites and congestion on the access roads. To mitigate the adverse traffic effects, the police usually implement temporary traffic management measures to control the number of visitors accessing the sites. However, these measures often ignore visitorsā€™ arrival time preferences and hence their effectiveness is questionable. This study models and analyses the arrival time preferences of cemetery and columbarium visitors under various transport mode scenarios. The model development is based on 3128 choice decisions collected from 782 respondents. A mixed logit model is calibrated to investigate the potential taste heterogeneity of the respondents, and a likelihood ratio test demonstrates that the model is superior to a standard multinomial logit model and provides a better fit to the survey data. The model results indicate that in-vehicle travel time, total waiting and walking time, and the provision and travel fare of feeder services are significant factors influencing cemetery and columbarium visitorsā€™ arrival time choices. The effects of socio-economic factors are also examined and discussed. Based on the model results, recommendations are provided for managing the travel demand to cemeteries and columbaria at peak and off-peak hours on or around festival days.postprin

    Multivariate space-time modelling of multiple air pollutants and their health effects accounting for exposure uncertainty

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    The long-term health effects of air pollution are often estimated using a spatio-temporal ecological areal unit study, but this design leads to the following statistical challenges: (1) how to estimate spatially representative pollution concentrations for each areal unit; (2) how to allow for the uncertainty in these estimated concentrations when estimating their health effects; and (3) how to simultaneously estimate the joint effects of multiple correlated pollutants. This article proposes a novel 2-stage Bayesian hierarchical model for addressing these 3 challenges, with inference based on Markov chain Monte Carlo simulation. The first stage is a multivariate spatio-temporal fusion model for predicting areal level average concentrations of multiple pollutants from both monitored and modelled pollution data. The second stage is a spatio-temporal model for estimating the health impact of multiple correlated pollutants simultaneously, which accounts for the uncertainty in the estimated pollution concentrations. The novel methodology is motivated by a new study of the impact of both particulate matter and nitrogen dioxide concentrations on respiratory hospital admissions in Scotland between 2007 and 2011, and the results suggest that both pollutants exhibit substantial and independent health effects

    Public transport service provisions and policy implications for columbarium trips

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    Grave-sweeping is one of the popular special events in Asian cities, especially in Chinese societies, in which families express filial piety to their ancestors during two traditional grave-sweeping festivals in a year. The extraordinary high travel demand is often attracted to columbaria within a relative short period around the festivals, and induces severe impacts to the local traffic. It is challenging for the government and private operators to formulate a public transport service setting to satisfactorily cater all the visitors' travel demand. This paper aims to propose an optimization framework to identify the optimal provisions of public transport services for columbarium trips to achieve consumer surplus or profit maximization. Numerical studies are carried out using the travel demand data collected from a selected columbarium, to examine the effects of different public transport service settings to the policy objectives in various cases. The model results show that the current situation is neither consumer surplus nor profit optimum. Improvement schemes are suggested in relation to allow various fares during different visit periods and provide multiple public transport feeder services to serve the visitors during the high travel demand period.published_or_final_versio

    An ARIMA-intervention analysis model for the financial crisis in China's manufacturing industry

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    2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Paediatric nurses' attitudes towards the promotion of healthy eating

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    This study assessed paediatric nurses' attitudes towards promoting healthy eating and their opinions regarding nurses as role models for health. In all, 67 nurses from 14 wards at an acute hospital trust completed questionnaires on weight, diet, physical activity, self-efficacy and attitudes towards nurses as role models for health. Forty-eight percent felt that they could incorporate health promotion into their patient care better, and 84% believed that nurses should present themselves as role models for health. Nurses felt that their own health behaviours influenced the quality of their care: 77% reported that patients and families would heed advice better from those who appeared to follow it themselves, and 48% reported difficulties in promoting health behaviours they did not adhere to themselves. These views were inconsistent with their own lifestyle choices, since one third of respondents did not meet physical-activity guidelines, almost half were an unhealthy weight, and the majority did not consume five portions of fruits/vegetables per day. Paediatric nurses identified barriers and facilitators to promoting healthy eating. Education, training and access to evidence-based resources may help to increase paediatric nurses' confidence to promote healthy eating to children and their families. Hospital workplaces should make provision to support nurses who seek to improve their own health
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