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101.
Abstract The increasing capacity of technological tools, as well as the advent of geographic information systems, has multiplied the ability to process large sets of microdata. At the same time, modeling concerns and the quest for a more in-depth understanding of individual behaviors is requiring more, and better, data. The gap between scientific modeling and informational tools for decision-making seems to be widening. In the Greater Montreal area, large sets of microdata have been available for more than 30 years. Along with the development of modeling and planning tools, particular attention has been given to the continuous enlightening of planners and decision-makers with respect to the outcomes of the various surveys. This has led to the development of particular interactive tools, specifically addressed at local planners, which present the most significant information regarding travel and demography, for geopolitically relevant areas. This paper presents the most recent interactive tool that has been developed for local planners in the Montreal area. It integrates information from both the most recent travel survey held in the region and the Canadian census. It offers both ease of use and relevant analytical means to assist in exploring the complex relations between spatial locations, demographic features, and activity-travel indicators. 相似文献
102.
Vassilis Kitidis Louise Tizzard Günther Uher Alan Judd Rob C. Upstill-Goddard Ian M. Head Neil D. Gray Gillian Taylor Ruth Durn Raquel Diez Jorge Iglesias Soledad García-Gil 《Journal of Marine Systems》2007,66(1-4):258
Methane (CH4) concentrations were measured in the water column, in sediment porewaters, and in atmospheric air, in the Ría de Vigo, NW Spain, during both the onset (April 2003) and at the end of (September 2004) seasonal upwelling. In addition, CH4 concentration and stable isotopic signatures (δ13CH4) were measured in porewaters, and sediment methanogenesis and aerobic oxidation of CH4 were determined in sediment incubations. Surface water column CH4 (2 m depth) was in the range 3–180 nmol l− 1 (110–8500% saturation) and followed a generally landward increase but with localised maxima in both the inner and middle Ría. These maxima were consistent with CH4 inputs from underlying porewaters in which CH4 concentrations were up to 3 orders of magnitude higher (maximum 350 μmol l− 1). Surface water CH4 concentrations were approximately three times higher in September than in April, consistent with a significant benthic CH4 flux driven by enhanced sediment methanogenesis following the summer productivity maximum. CH4 and δ13CH4 in sediment porewaters and in incubated sediment slurries (20 °C) revealed significant sediment CH4 oxidation, with an apparent isotopic fractionation factor (rc) of 1.004. Using turbulent diffusion models of air–sea exchange we estimate an annual emission of atmospheric CH4 from the Ría de Vigo of 18–44 × 106 g (1.1–2.7 × 106 mol). This estimate is approximately 1–2 orders of magnitude lower than a previous estimate based on a bubble transport model. 相似文献
103.
Christer Richt 《轨道交通》2009,(3):74-74
要想以相对较高的生产效率来加工耐热超级合金,必须充分仔细地准备相应的加工策略。由于加工此类材料的零件时至少50%以上的工序为车削,因此其基本原则应立足于采用合适的切削刃切入方法。 相似文献
104.
This paper develops a comprehensive approach to the definition of transportation analysis zones (TAZ), and therein, presents
a new methodology and algorithm for the definition of TAZ embedded in geographic information systems software, improves the
base algorithm with several local algorithms, and comprehensively analyses the obtained results. The results obtained are
then compared to these presently used in the transportation analysis process of the Lisbon Metropolitan Area. The proposed
algorithm presents a new methodology for TAZ design based on a smoothed density surface of geocoded travel demand data. The
algorithm aims to minimise the loss of information when moving from a continuous representation of the origin and destination
of each trip to their discrete representations through zones, and focuses on the trade-off between the statistical precision,
geographical error, and the percentage of intra-zonal trips of the resulting OD matrix. The results for the Lisbon Metropolitan
Area case study suggest a significant improvement in OD matrix estimates compared to current transportation analysis practises
based on administrative units.
Luis M. Martínez is a Civil Engineer from the Instituto Superior Técnico, Technical University of Lisbon since 2004. After finishing his degree, he started his work as researcher in the CESUR (Civil Engineering & Architecture Department—Instituto Superior Técnico) where he has been working since. In 2006 he completed his Master Thesis at Instituto Superior Técnico on Traffic Analysis Zones modeling and started his PhD studies on the theme: Metropolitan Transportation Systems Financing Using the Value Capture Concept. José Manuel Viegas is Full Professor of Transportation at the Civil Engineering & Architecture Department of the Instituto Superior Técnico, Technical University of Lisbon. He has worked extensively in Modeling, Innovation and Policy in several types of Transport Systems. He was founder and first Director General of Transportnet, a group of eight leading European Universities with Advanced Studies in Transportation, and currently leads the Portuguese side of the Transportation Systems area in the MIT—Portugal program. Elisabete A. Silva is at the University of Cambridge (University Lecturer in Planning at the Department of Land Economy and a Fellow of Robinson College). With more than 100 contributions in peer review journals, books/books chapters, conference proceedings, and a research track record of approximately 16 years, (both at the public and private sector), her research interests are centred on the application of new technologies to spatial planning in particular city and metropolitan dynamic modelling through time. 相似文献
Elisabete A. SilvaEmail: |
Luis M. Martínez is a Civil Engineer from the Instituto Superior Técnico, Technical University of Lisbon since 2004. After finishing his degree, he started his work as researcher in the CESUR (Civil Engineering & Architecture Department—Instituto Superior Técnico) where he has been working since. In 2006 he completed his Master Thesis at Instituto Superior Técnico on Traffic Analysis Zones modeling and started his PhD studies on the theme: Metropolitan Transportation Systems Financing Using the Value Capture Concept. José Manuel Viegas is Full Professor of Transportation at the Civil Engineering & Architecture Department of the Instituto Superior Técnico, Technical University of Lisbon. He has worked extensively in Modeling, Innovation and Policy in several types of Transport Systems. He was founder and first Director General of Transportnet, a group of eight leading European Universities with Advanced Studies in Transportation, and currently leads the Portuguese side of the Transportation Systems area in the MIT—Portugal program. Elisabete A. Silva is at the University of Cambridge (University Lecturer in Planning at the Department of Land Economy and a Fellow of Robinson College). With more than 100 contributions in peer review journals, books/books chapters, conference proceedings, and a research track record of approximately 16 years, (both at the public and private sector), her research interests are centred on the application of new technologies to spatial planning in particular city and metropolitan dynamic modelling through time. 相似文献
105.
A package of large-scale investments in the transportation infrastructure in the Stockholm metropolitan region is currently being proposed. It contains new investments in the railway and subway systems as well as new links in the road system. This paper deals with the issue of appraising this kind of investment program. One major problem is the lack of a unique standard method, and it is argued that several tools should be used in a practical evaluation of large-scale investments in the transportation system.Four different approaches are presented and related to each other. First, one study uses a network-based mode-split/assignment model with a fixed trip matrix. The second study is complementary, as its aim is to also trace the impacts on the spatial distribution of population and jobs by applying an integrated transportation and land use model. Third, the long-run effects of the investments on regional economic growth are discussed within the framework of regional production functions. Fourth, an alternative approach is used, in which benefits from the investments are assessed through their estimated influence on aggregate land values.Abbreviations RA
Reference Alternative
- IP
Investment Proposal
- IMREL
Integrated Model of Residential and Employment Location
- RPFM
Regional Production Function Model
An earlier version of this paper was presented at the 31th European Congress of the Regional Science Association, Lisbon, August 1991. 相似文献
106.
王宇 《西安交通大学学报(英文版)》1995,(2)
ENHANCEDNITRICOXIDE(NO)-MEDIATEDVASODILATIONINLOWPOTASSIUMMEDIUMwagnYu;OS.Steinsland,SH.Nelson,AE.Feerick,WE.Johnstonn(Depart?.. 相似文献
107.
108.
A cooperative waiting strategy based on elliptical areas for the Dynamic Pickup and Delivery Problem with Time Windows
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The purpose of this paper to present a cooperative scheduling algorithm for solving the Dynamic Pickup and Delivery Problem with Time Windows (DPDPTW). The idea behind cooperative waiting strategies is to calculate simultaneously the waiting times for all nodes in the solution. Classical non‐cooperative scheduling algorithms perform the scheduling for each route independently of the scheduling of the other routes. We present the Cooperative Scheduling Problem (CSP) based on the elliptical areas generated by vehicles waiting at their nodes. The CSP is solved by means of a genetic algorithm and is evaluated by using a set of benchmarks based on real‐life data found in the literature. Initially, two waiting strategies are presented: Wait‐Early‐Time scheduling and Balanced‐Departure scheduling. Extensive empirical simulations have been carried out by analyzing the degree of dynamism and the average waiting time, a new concept defined to take into account the gap between the time windows of pickup and delivery nodes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
109.
Tolls have increasingly become a common mechanism to fund road projects in recent decades. Therefore, improving knowledge of demand behavior constitutes a key aspect for stakeholders dealing with the management of toll roads. However, the literature concerning demand elasticity estimates for interurban toll roads is still limited due to their relatively scarce number in the international context. Furthermore, existing research has left some aspects to be investigated, among others, the choice of GDP as the most common socioeconomic variable to explain traffic growth over time. This paper intends to determine the variables that better explain the evolution of light vehicle demand in toll roads throughout the years. To that end, we establish a dynamic panel data methodology aimed at identifying the key socioeconomic variables explaining changes in light vehicle demand over time. The results show that, despite some usefulness, GDP does not constitute the most appropriate explanatory variable, while other parameters such as employment or GDP per capita lead to more stable and consistent results. The methodology is applied to Spanish toll roads for the 1990–2011 period, which constitutes a very interesting case on variations in toll road use, as road demand has experienced a significant decrease since the beginning of the economic crisis in 2008. 相似文献
110.
María Feo-Valero Leandro García-Menéndez Salvador del Saz-Salazar 《Transportation》2016,43(1):101-122
This paper analyses the choice between road and rail in Spain where rail market share for freight is still residual. Discrete choice models are estimated with data obtained through a two-phase fieldwork, thus allowing us to carry out a stated preference efficient design for each interviewee. We analyse the existence of attribute cut-offs and the presence of a segment of the population with a zero value of frequency. Our results show that ignoring the existence of cut-offs and segments of the population with polarised valuations can lead to erroneous conclusions in terms of the possibilities of rail for absorbing significant quota. 相似文献