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51.
Providing public transport in areas of low demand has long proved to be a challenge to policy makers and practitioners. With the developing economic, social and environmental trends, there is pressure for alternative solutions to the policy of subsidising conventional bus services. One potential solution is to adopt more flexible routes and/or timetables to better match the required demand. Therefore such ‘on demand’ or ‘Demand Responsive Transport’ (DRT) services (known as paratransit in the US) have been adopted in a number of locations. This paper seeks to explore the effects of area-wide factors on the demand of DRT by reporting the results of a statistical analysis of DRT service provision in the metropolitan region of Greater Manchester, the public transport authority of which offers one of the largest and most diverse range of DRT schemes in the UK. Specifically, this paper employs a multilevel modelling approach to investigate the impact of both DRT supply-oriented factors at the service area level and socio-economic factors at the lower super output area (LSOA) level on the average number of trips made by DRT per year. This hierarchical or ‘nested’ structure was adopted because typically the LSOAs within the same Service Area may share similar characteristics. It is found that the demand for DRT services was higher in areas with low car ownership, low population density, high proportion of white people, and high levels of social deprivation, measured in terms of income, employment, education, housing and services, health and disability, and living environment. 相似文献
52.
Gordon E. Beanlands 《Coastal management》2013,41(1-2):117-132
Abstract The management of estuarine areas in Canada has received little attention; this is specifically the case along the Atlantic coast. This article reviews the importance of estuaries as resources and analyzes the land‐use pressures which can affect them. Specific emphasis is placed on the results of a recent study of estuaries in Atlantic Canada. The incidence of the closures of shellfish areas is used as a measure of the impact of land development on estuaries. 相似文献
53.
Transportation - Urban utility cycling is being promoted widely due to various health, social, economic and environmental benefits. This study seeks to identify and rank which municipal-level... 相似文献
54.
The quenching of a metal component with a channel section in a water tank is numerically simulated. Computational fluid dynamics
(CFD) is used to model the multiphase flow and the heat transfer in film boiling, nucleate boiling and convective cooling
processes to calculate the difference in heat transfer rate around the component and then combining with the thermal simulation
and structure analysis of the component to study the effect of heat transfer rate on the distortion of the U-channel component.
A model is also established to calculate the residual stress produced by quenching. The coupling fluid-thermal-structural
simulation provides an insight into the deformation of the component and can be used to perform parameter analysis to reduce
the distortion of the component. 相似文献
55.
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57.
C. Marsh T.J. Gordon Q.H. Wu 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(8):597-616
This study considers a new design methodology in the context of active vehicle suspension control. The approach combines concepts from Stochastic Optimal Control with those of Learning Automata. A learning automaton effectively learns optimal control on-line in the vehicle, in an appropriate stochastic “test-track” environment. For practical application, the overwhelming advantage of this approach is that no explicit modelling is required, and considerable time savings may be expected in system development. This simulation study considers the on-line learning of optimal control in a low-bandwidth active suspension system, where control feedback is confined to a body-mounted accelerometer at each corner of the vehicle. It is shown that learning can successfully take place under a range of conditions, including the case when there is substantial transducer noise. The performance of the resulting control system is shown to depend heavily on the nature of the learning environment. 相似文献
58.
The effect of location,mobility and socio-demographic factors on task and time allocation of households 总被引:1,自引:0,他引:1
This paper investigates the role of location factors in task and time allocation at the household level. It is hypothesized
that, if time constraints are less binding as a result of living in an urban area or owning more cars, spouses engage more
often and longer in out-of-home activities and schedule their activities more independently. The hypotheses are tested with
logistic and Cox regression models of activity participation and time allocation on a data set collected in the Amsterdam–Utrecht
region in the Netherlands. Results suggest that the hypotheses are supported with respect to specific household activity scheduling
decisions. 相似文献
59.
This paper introduces a new method for the prediction of ship maneuvering capabilities. The new method is added to a nonlinear
six-degrees-of-freedom ship motion model named the digital, self-consistent ship experimental laboratory (DiSSEL). Based on
the first principles of physics, when the ship is steered, the additional surge and sway forces and the yaw moment from the
deflected rudder are computed. The rudder forces and moments are computed using rudder parameters such as the rudder area
and the local flow velocity at the rudder, which includes contributions from the ship velocity and the propeller slipstream.
The rudder forces and moments are added to the forces and moments on the hull, which are used to predict the motion of the
ship in DiSSEL. The resulting motions of the ship influence the inflow into the rudder and thereby influence the force and
moment on the rudder at each time step. The roll moment and resulting heel angle on the ship as it maneuvers are also predicted.
Calm water turning circle predictions are presented and correlated with model test data for NSWCCD model 5514, a pre-contract
DDG-51 hull form. Good correlations are shown for both the turning circle track and the heel angle of the model during the
turn. The prediction for a ship maneuvering in incident waves will be presented in Part 2. DiSSEL can be applied for any arbitrary
hull geometry. No empirical parameterization is used, except for the influence of the propeller slipstream on the rudder,
which is included using a flow acceleration factor. 相似文献
60.
Katie Hogg María Semitiel-García Pedro Noguera-Méndez Tim Gray Sarah Young 《Coastal management》2018,46(1):58-74
Many marine protected areas (MPAs) face a multitude of threats to the ecosystems that they have been established to conserve. This study is based on 111 interviews conducted in 2013–2014 designed to discover the perceptions of stakeholders about the threats, the causes of the threats, and their responses to the threats, to a well-established MPA – Cabo de Palos - Islas Hormigas (CPH-MPA). This MPA was created to safeguard fisheries and the associated artisanal fishers, but over time it has become a tourism “hotspot.” Resilience theory, which incorporates ecological resilience, social resilience, and individual resilience, helps us to analyze stakeholders' responses to threats by categorizing them into passive, adaptive, and transformative responses. We found respondents identified four main threats – over-fishing, excessive scuba diving, pollution, and invasive species; attributed the threats to three main causes – ineffective management, poor environmental stewardship, and climate change; and expressed three kinds of responses – do nothing, adapt, or transform – with a preference for adaptation and (especially) transformation. The lesson of this study is that it shows how, unless drastic action is taken to curb recreational diving activities, the CPH-MPA is in danger of changing from a fishing reserve to a largely unregulated leisure diving venue, which is unlikely to fulfill the requirements of resilience; ecological, social, or individual. 相似文献