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891.
为探讨外生性面神经雪旺氏细胞瘤的病理来源及病因 ,对 152 6耳颞骨连续切片进行组织病理学观察。结果发现 :39耳在面神经骨性管裂处显示神经外膜先天性缺损 ,神经主干由此疝出。其中31耳 ,在疝出面神经凸面有明显的雪旺氏细胞增生。这 31耳中 ,有 12耳在卵圆窗上方 ,1耳在面神经第二膝部形成小的外生性雪旺氏细胞瘤。提示 :管裂处神经外膜的先天性缺损是面神经由此疝出的组织解剖学原因。面神经疝出可能是刺激雪旺氏细胞增生 ,以致形成外生性面神经雪旺氏细胞瘤的直接原因。 相似文献
892.
The development and initial validation results of a micro-simulator for the generation of daily activity-travel patterns are
presented in this paper. The simulator assumes a sequential history and time-of-day dependent structure. Its components are
developed based on a decomposition of a daily activity-travel pattern into components to which certain aspects of observed
activity-travel behavior correspond, thus establishing a link between mathematical models and observational data. Each of
the model components is relatively simple and is estimated using commonly adopted estimation methods and existing data sets.
A computer code has been developed and daily travel patterns have been generated by Monte Carlo simulation. Study results
show that individuals' daily travel patterns can be synthesized in a practical manner by micro-simulation. Results of validation
analyses suggest that properly representing rigidities in daily schedules is important in simulating daily travel patterns.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
893.
Elvezia M. Cepolina Alessandro Farina 《Transportation Research Part C: Emerging Technologies》2012,21(1):230-243
The paper concerns the conceptual design of a transport system for pedestrian areas. The proposed transport system is based on a fleet of eco-sustainable Personal Intelligent City Accessible Vehicles (PICAVs). The vehicles are shared through the day by different users and the following specific services will be provided: instant access, open ended reservation and one way trips. Referring to the proposed transport system, a new methodology to optimise the fleet dimension and its distribution among the stations is proposed in this paper. The problem faced is an optimisation problem where the cost function to be minimised takes into account both the transport system cost and the user costs that depend on the waiting times. A random search algorithm has been adopted. Given a fleet dimension and its distribution among the stations, the waiting times of the users are assessed by a microscopic simulation. The simulation model tracks the second-by-second activity of each PICAV user, as well as the second-by-second activity of each vehicle. The overall methodology has been implemented in an object-oriented simulator. The proposed transport system has been planned and simulated for the historical city centre of Genoa, Italy. 相似文献
894.
Khandker M. Nurul Habib Catherine Morency 《Transportation Research Part A: Policy and Practice》2012,46(2):241-254
This paper presents an econometric model for the behaviour of carsharing users. The econometric model is developed to jointly forecast membership duration, the decision to become an active member in a particular month, and the frequency of monthly usage of active members. The model is estimated using the membership directory and monthly transaction data of a carsharing program, ‘Communauto Inc.’, based in Montréal, Canada. The model shows a high degree of fit to the observed dataset and provides many behavioural details of carsharing users. The results are instructive to carsharing planners in devising efficient policies. 相似文献
895.
The Bay of La Paz, a coastal and shallow basin of the Gulf of California (depth<420 m), exchanges mixed-layer waters with the Gulf of California predominantly through Boca Grande (Big Mouth), in the northeastern part of the bay. Equatorial Surface Water (ESW) flows from the gulf to the bay; once there, due to evaporation processes, this water increases its salinity above 35.00, therefore becoming Gulf of California Water (GCW) Mass. During June 1998, the baroclinic circulation in the bay was dominated by a cyclonic gyre. The hydrographic dome, related to this gyre, is depicted until approximately 150-m depth. However, the vertical mixing of water between the mixed-layer and the ones below practically does not occur because of the development of a sharp pycnocline. This fact and the isolation of the bottom of the bay by a bathymetric sill (approximately 250-m depth) at Boca Grande induce low oxygen content, particularly in the bottom-waters (O2<0.1 ml/l). Chlorophyll values are higher and with larger vertical fluctuations within the Bay of La Paz than outside. 相似文献
896.
Khandker M. Nurul Habib Nicholas Day Eric J. Miller 《Transportation Research Part A: Policy and Practice》2009,43(7):639-653
The trip timing and mode choice are two critical decisions of individual commuters mostly define peak period traffic congestion in urban areas. Due to the increasing evidence in many North American cities that the duration of the congested peak travelling periods is expanding (peak spreading), it becomes necessary and natural to investigate these two commuting decisions jointly. In addition to being considered jointly with mode choice decisions, trip timing must also be modelled as a continuous variable in order to precisely capture peak spreading trends in a policy sensitive transportation demand model. However, in the literature to date, these two fundamental decisions have largely been treated separately or in some cases as integrated discrete decisions for joint investigation. In this paper, a discrete-continuous econometric model is used to investigate the joint decisions of trip timing and mode choice for commuting trips in the Greater Toronto Area (GTA). The joint model, with a multinomial logit model for mode choice and a continuous time hazard model for trip timing, allows for unrestricted correlation between the unobserved factors influencing these two decisions. Models are estimated by occupation groups using 2001 travel survey data for the GTA. Across all occupation groups, strong correlations between unobserved factors influencing mode choice and trip timing are found. Furthermore, the estimated model proves that it sufficiently captures the peak spreading phenomenon and is capable of being applied within the activity-based travel demand model framework. 相似文献
897.
Studying travel-related individual assessments and desires by combining hierarchically structured ordinal variables 总被引:1,自引:1,他引:0
Ordinal measures are frequently encountered in travel behavior research. This paper presents a new method for combining them
when a hierarchical structure of the data can be presumed. This method is applied to study the subjective assessment of the
amount of travel by different transportation modes among a group of French clerical workers, along with the desire to increase
or decrease the use of such modes. Some advantages of this approach over traditional data reduction technique such as factor
analysis when applied to ordinal data are then illustrated. In this study, combining evidence from several variables sheds
light on the observed moderately negative relationship between the personal assessment of the amount of travel and the desire
to increase or decrease it, thus integrating previous partial (univariate) results. We find a latent demand for travel, thus
contributing to clarify the behavioral mechanisms behind the induced traffic phenomenon. Categorizing the above relationship
by transportation mode shows a desire for a less environmental-friendly mix of modes (i.e., a greater desire to use heavy
motorized modes and a lower desire to use two-wheeled modes), whenever the respondents do not feel to travel extensively.
This result, combined with previous theoretical investigations concerning the determinants of the desire to alter trips consumption
levels, shows the importance of making people aware of how much they travel.
Marco Diana is a permanent researcher working at the Department of Hydraulics, Transport and Civil Infrastructures of Politecnico di Torino, Italy. His research interests include the study of innovative forms of public transport services and the analysis of multimodality behaviors. Tingting Song is a Scientific Programmer at The Rockefeller University, Center for Clinical and Translational Science, Biostatistics, Epidemiology, and Research Design Core, New York, NY, USA. She works on algorithms for non-parametric methods and their applications in medical research. She maintains the muStat package on CRAN.r-project.org and the Web server on muStat.rockefeller.edu. Knut M. Wittkowski is a Senior Research Associate at The Rockefeller University and Head of Biostatistics, Epidemiology, and Research Design at its Center for Clinical and Translational Science, New York, NY, USA. His research focuses on methods, meta data, and user interfaces to integrate nonparametric statistics into research and decision support systems. 相似文献
Knut M. WittkowskiEmail: |
Marco Diana is a permanent researcher working at the Department of Hydraulics, Transport and Civil Infrastructures of Politecnico di Torino, Italy. His research interests include the study of innovative forms of public transport services and the analysis of multimodality behaviors. Tingting Song is a Scientific Programmer at The Rockefeller University, Center for Clinical and Translational Science, Biostatistics, Epidemiology, and Research Design Core, New York, NY, USA. She works on algorithms for non-parametric methods and their applications in medical research. She maintains the muStat package on CRAN.r-project.org and the Web server on muStat.rockefeller.edu. Knut M. Wittkowski is a Senior Research Associate at The Rockefeller University and Head of Biostatistics, Epidemiology, and Research Design at its Center for Clinical and Translational Science, New York, NY, USA. His research focuses on methods, meta data, and user interfaces to integrate nonparametric statistics into research and decision support systems. 相似文献
898.
There has been a great deal of research on deriving estimates of the value of travel time savings (VTTS) as a way of converting
travel time benefits of toll roads relative to free routes into monetary units, the major user benefit in the development
of forecasts of traffic and hence revenue streams. By contrast there has been almost no consideration given to identifying
the role that various tollroad products play in establishing preferences for toll routes over non-tolled routes. Increasingly
tollroads give users the option to pay by cash at a toll booth, by electronic tolling or by a pre- or post-paid debit and
credit account system involving vehicle identification. The efficiency gained by electronic tolling for both the users and
the operator have resulted in moves in many jurisdictions to eliminate cash collection entirely (or not introduce it when
introducing a new tolled road facility), and to introduce a range of pre- and post-payment options. This has been accompanied
by a growing move to distance-based charging in some contexts which is more cumbersome to structure with a cash option. This
paper investigates current and potential travellers’ preferences for a range of toll products and how much individual’s are
willing to pay for very specific toll products. Data from a stated choice experiment is used in a mixed logit model to establish
the role that toll products play in the context of offered times and costs of alternative routes, in choosing between alternative
ways of paying for the use of tolled routes.
David A. Hensher is Professor of Management, and Founding Director of the Institute of Transport and Logistics Studies. David is a Fellow of the Academy of Social Sciences in Australia, Recipient of the 2006 Engineers Australia Transport Medal for lifelong contribution to transportation, member of Singapore Land Transport Authority International Advisory Panel (Chaired by Minister of Transport). David is on the editorial boards of 10 of the leading transport journals and Area Editor of Transport Reviews. David was appointed in 1999 by one of the worlds most prestigious academic publishing houses—Elsevier Science press as series and volume editor of a new handbook series “Handbooks in Transport”. Appointments over recent years include: a member of the executive committee that reviewed bus transport bids for the Olympic Games, the NSW Government’s Peer Review Committee for the Sydney Strategic Transport Plan, Peer reviewer for Transfund (NZ) of the New Zealand project evaluation program, Peer reviewer of the NZ Land Passenger Transport Procurement Strategy for Land Transport NZ, member of the executive committee of ATEC, a consortium promoting a freight rail system between Melbourne and Darwin; economic adviser to Gilbert+Tobin Lawyers on valuation methods in IP context; panel member of NSW Ministry of Transport benchmarking program; specialist toll road project adviser to Thiess. John M. Rose is Director of the Industry Program and a Deputy Director at Institute of Transport and Logistics Studies (ITLS). John’s research interests are in the areas of discrete choice modelling and efficient stated choice experiments. John has several articles published in the top Transportation and Logistics journals (including Transportation, Transportation Research A, B and E) and is a co-author of (with Professors David Hensher and William Greene) Applied Choice Analysis; A Primer, (2005) by Cambridge University Press. He is currently writing a book on generating efficient stated choice experimental designs (with Mike Bliemer, Delft). 相似文献
John M. RoseEmail: |
David A. Hensher is Professor of Management, and Founding Director of the Institute of Transport and Logistics Studies. David is a Fellow of the Academy of Social Sciences in Australia, Recipient of the 2006 Engineers Australia Transport Medal for lifelong contribution to transportation, member of Singapore Land Transport Authority International Advisory Panel (Chaired by Minister of Transport). David is on the editorial boards of 10 of the leading transport journals and Area Editor of Transport Reviews. David was appointed in 1999 by one of the worlds most prestigious academic publishing houses—Elsevier Science press as series and volume editor of a new handbook series “Handbooks in Transport”. Appointments over recent years include: a member of the executive committee that reviewed bus transport bids for the Olympic Games, the NSW Government’s Peer Review Committee for the Sydney Strategic Transport Plan, Peer reviewer for Transfund (NZ) of the New Zealand project evaluation program, Peer reviewer of the NZ Land Passenger Transport Procurement Strategy for Land Transport NZ, member of the executive committee of ATEC, a consortium promoting a freight rail system between Melbourne and Darwin; economic adviser to Gilbert+Tobin Lawyers on valuation methods in IP context; panel member of NSW Ministry of Transport benchmarking program; specialist toll road project adviser to Thiess. John M. Rose is Director of the Industry Program and a Deputy Director at Institute of Transport and Logistics Studies (ITLS). John’s research interests are in the areas of discrete choice modelling and efficient stated choice experiments. John has several articles published in the top Transportation and Logistics journals (including Transportation, Transportation Research A, B and E) and is a co-author of (with Professors David Hensher and William Greene) Applied Choice Analysis; A Primer, (2005) by Cambridge University Press. He is currently writing a book on generating efficient stated choice experimental designs (with Mike Bliemer, Delft). 相似文献
899.
Daniel A. Rodríguez Elizabeth M. Brisson Nicols Estupin 《Transportation Research Part D: Transport and Environment》2009,14(7):470-478
Few studies have examined the relationship between micro-scale features of the built environment and street segment usage. Micro-scale features of the built environment include the width of the sidewalk, the presence of amenities such as benches and trash bins, and the presence of crossing aids such as stoplights and crosswalks. This study employs segment-level primary data collected for 338 street segments in close proximity to one of 71 bus rapid transit stations in Bogotá, Colombia. We also use secondary data to control for area-level characteristics such as density, socio-economic stratum, unemployment, and crime. Factor and regression analyses are to use identify two dimensions of the built environment that are associated with higher levels of pedestrian activity: pedestrian-friendly amenities, comprised of wider and higher quality sidewalks and the presence of amenities such as benches, garbage cans, and bike paths; and connectivity, comprised of higher levels of road density, three- and four-way intersections, and density. In addition, we find greater pedestrian activity on segments with higher development intensity, with more mix of land uses, and with more crossing aids. Although the relationships identified are not causal, they are suggestive in terms of planning successful built environment interventions. 相似文献
900.
Hybridation of generation propagation models and SPH model to study severe sea states in Galician Coast 总被引:1,自引:0,他引:1
A.J.C. Crespo M. Gmez-Gesteira P. Carracedo R.A. Dalrymple 《Journal of Marine Systems》2008,72(1-4):135
The Atlantic and Cantabrian coasts of the Iberian Peninsula suffer the periodic passage of storms which give rise to severe sea states. Standard generation- propagation models (WAM, WAVEWATCH, SWAN) are commonly used for operational oceanography purposes with satisfactory results both in the open ocean and in near shore areas but they do not provide information about the possibility of flooding in coastal areas. A 2D HV version of SPH (Smoothed Particle Hydrodynamics) model is considered to propagate the signal provided by generation- propagation models to the coast and to analyze the nature of coastal structures overtopping as a tool to create maps of risk. SPH is shown to provide valuable information about overtopping (maximum water height and water velocity) under the stormy conditions suffered by the Galician coast on February 17, 2006. 相似文献