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11.
In 1992, the Federal Highway Administration awarded small research contracts to four teams of transportation researchers to design alternative approaches for improving the urban travel demand forecasting process. The purpose of these contracts was to enable each research team to explain how transportation planning models could and should be improved to meet the new forecasting requirements brought on by recent legislation, to address the impacts of new transportation technology, and to exploit the travel behavior theories and methodologies that have developed over the past two decades.This paper presents a summary and synthesis of the ideas which emerged from the four research reports. Its purpose is to identify common themes suggested by several of the research teams, to point out what appear to be critical elements missing from some approaches, and to combine the best aspects of the four approaches into a research plan for improving the current generation of travel demand models.Abbreviations CAAA Clean Air Act Amendments - FHWA Federal Highway Administration - GIS Geographic Information System - IIA Independence of Irrelevant Alternatives - IT Information Technology - IVHS Intelligent Vehicle Highway System - SUE Stochastic User Equilibrium - TCM Transportation Control Measures - UTPS Urban Transportation Planning System - VMT Vehicle Miles of Travel The paper was prepared as a report for the Federal Highway Administration.  相似文献   
12.

Foreign consultants still provide much of the analytical expertise for transport planning studies conducted in the Gulf States and other rapidly developing countries. Most of the systems analysis techniques used are adaptations of those developed for western urban areas. The populations of the Gulf States are unique in that they contain very large populations of foreign workers who have very different social and economic characteristics from the national populations. This paper describes these differences and shows how they have influenced the spatial evolution of the Kuwait metropolitan area and the associated transport demands. The paper also describes the analytical tools that are most appropriate for capturing the transport behaviour of residents of the Kuwait metropolitan area.  相似文献   
13.
1 引言 伴随着20世纪初Thomas Coslett及其他众多人士的研究工作,在1943年引入了Jernstadt磷酸盐后,诞生了今天人们所熟知的用于镀锌工艺前预浸处理的含钛磷酸氢二钠溶液.使用该磷酸盐后,可以更快地形成更为细小的磷酸锌晶体组织.过去60多年间,这种基础工艺在众人的努力下愈发精细,但是基本的化学特性及功能仍然保持不变.  相似文献   
14.
Climate change adaptation presents a difficult challenge for coastal towns around the world, forcing local governments to plan for sea level rise in a contentious decision-making space. The concept of “adaptation pathways,” a diagnostic and analytical tool to assist in adaptive planning and decision-making, is gaining traction as a way of framing and informing climate adaptation. It provides decisionmakers a way to acknowledge the inter-temporal complexities and uncertainties associated with the novel dynamics of climate change and a mechanism to manage these challenges in the local context. In 2012, the Australian Government funded an 18-month program to provide decisionmakers in the coastal zone an opportunity to test the utility of the adaptation pathways concept for coastal climate adaptation. Using a selection of completed projects as case studies, we performed a document analysis to better understand the learnings from the projects. The main themes surrounded: (1) the utility of the adaptation pathway framework in developing options, (2) decision-making rationale and criteria, and (3) stakeholder participation in pathway development. A project participant survey was developed to further understand these themes. Our analysis reveals that “adaptation pathways” was generally framed narrowly and conservatively to emphasize extant economic, administrative and legal considerations over community, participatory, or exploratory ones. Although some case study projects were able to reach a point in the pathway discussion to actively involve stakeholders in their decision-making process, many case studies continued to build technical data as a method for defending policies and actions. These results indicate that coastal adaptation can take-up adaptation pathways as a useful concept for decision-making and planning; however, many councils may still require assistance in stakeholder communication processes in order to develop sociallyacceptable plans that take into account the full range of values affecting local coastal environments.  相似文献   
15.
The improved monitoring and modeling capability resulting from recent technological advances in oceanographic sensors, computer processing power, and telecommunications can play a major role in environmental preservation. In particular, this capability can help improve: safe navigation and thus the prevention of maritime accidents that lead to hazardous spills; the effective cleanup of hazardous spills when they do occur; the real-time assessment of water quality problems; the assessment of long-term trends and variability due to both anthropogenic and climate change effects; and the understanding of key physical, chemical, and ecological processes. Presented at the International Conference on Technologies for Marine Environment Preservation (MARIENV’95), Tokyo, Japan, September 24–29, 1995  相似文献   
16.
A new automated quality control system for oceanic temperature and temperature–salinity profiles is presented. Substantial development was needed for some of the quality control algorithms although the checks were based on documented procedures used elsewhere where appropriate. A new automated ship track check was developed: the results of an undetected position error can be very damaging to ocean analyses. Also important is a check against a gridded background, this can be a climatology but near the surface it is advantageous to use an estimate that is evolving over time. Bayesian probability theory is used in the background check and the associated check against nearby observations (buddy check). The system was used to process archive data for 1956–2004. As a by-product monthly model-free objective analyses for this period were produced. Versions of the system are used for near-real time ocean analysis and for initialising both short-range ocean forecasts and seasonal atmosphere–ocean forecasts. The main features of the oceanic observing systems are presented along with quality control statistics, examples of errors that can occur and some additional problematic cases.  相似文献   
17.
货运车辆行车途中能否有安全便利的休息站,关系到联邦关于司机工作时间规定的执行及高效的车队运营.由于货运车辆的激增,中途停车站能力短缺问题日益凸显.本研究开发了一个基于互联网的地理信息系统,用于从用户大范围收集停车位短缺的地理信息.为了分析这些停车紧张点的地理分布,采用了点聚合和排名的方法来发现停车问题最严重的地区.另外,提出一种沿公路方向的单测度的聚合方法.其基本思路是,停车问题不是一个单点问题,而是一个区域性问题.缓解停车紧张,可通过增加区域性停车能力.本文发现能力紧张的区域通常在大都市的郊区,反映出很多长途司机在此停车等待第二天往市区内送货的运作规律.研究结果与来自公路巡警方面的观察结果一致.  相似文献   
18.
目的 本研究旨在了解大骨节病(KBD,在中国发生的一种地方性骨关节病)患者软骨CD44和蛋白聚糖的代谢及相关影响.方法 用免疫组织化学方法分析分化抗原-44(CD44)、BC-13以及3-B-3(-)在所采集KBD患者和正常人软骨切片中的表达;采用夹心酶联免疫吸附测定法检测血清中可溶性CD44(sCD44)、白介素-1β(IL 1β)、肿瘤坏死因子α(TNF-α)以及基质金属蛋白酶-1的水平.结果 苏木素&伊红(HE)染色以及甲苯胺兰染色显示,在KBD病患儿以及成人软骨中有细胞坏死和蛋白聚糖的缺失;免疫组织化学染色发现,KBD成人和儿童患者软骨组织中CD44、BC-13和3-B-3(-)具很强的阳性表达;sCD44、IL-1β和TNF-α在KBD成人和儿童血清的水平明显高于正常成人及儿童对照组,经统计学分析具显著性差异.有意思的现象是,KBD病区正常儿童血清中IL-1-β和TNF-α的水平亦明显高于非KBD病区正常儿童的水平,这些都提示可能还有一些未被确定的因素(例如遗传因素)或许对KBD发病具有一定的影响.结论 大骨节病患者CD44、IL-1β和TNF α代谢发生的改变,以及KBD成人和儿童软骨由于聚集蛋白聚糖酶活性增强所产生的蛋白聚糖的丢失,可能是KBD发病机理中起关键作用的重要因素,可以引起病态的关节形成和关节的不稳定,这些都可以导致在KBD患者中发生继发性的骨性关节炎.  相似文献   
19.
Bus rapid transit system is designed to provide high‐quality and cost‐efficient passenger transportation services. In order to achieve this design objective, effective scheduling strategies are required. This research aims at improving the operation efficiency and service quality of a BRT system through integrated optimization of its service headways and stop‐skipping strategy. Based on cost analysis for both passengers and operation agencies, an optimization model is established. A genetic algorithms based algorithm and an application‐oriented solution method are developed. Beijing BRT Line 2 has been chosen as a case study, and the effectiveness of the optimal headways with stop‐skipping services under different demand levels has been analyzed. The results has shown that, at a certain demand level, the proposed operating strategy can be most advantageous for passengers with an accepted increase of operating costs, under which the optimum headway is between 3.5 and 5.5 min for stop‐skipping services during the morning peak hour depending on the demand with the provision of stop‐skipping services. The effectiveness of the optimal headways with stop‐skipping services is compared with those of existing headways and optimal headways without stop‐skipping services. The results show that operating strategies under the optimal headways with stop‐skipping services outperforms the other two operating strategies with respect to total costs and in‐vehicle time for passengers. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
20.
Over the last 40 years, there has been an unprecedented growth in trade amongst countries, and the growth in trade shows no sign of slowing down. The increases in trade have put tremendous pressure on the maritime and port industries, and these industries have responded with innovations, investment, and greater productivity. International trade and maritime trade are synonyms, and an understanding of the determinants of international trade is central to understanding maritime trade. In this paper, we provide a review of the international trade literature with a focus on the determinants of trade and the evolution of trade modeling. We then present a broad overview of the extent and growth of trade in the context of primary determinants. The basic results are: (1) Trade is growing at a phenomenal rate; (2) Trade is dominated by relatively few countries who tend to remain dominant; (3) While trade of all products is growing, there are large differences in the growth rates, but yet, there is stability in the relative sizes of product markets; and (4) Over the last 40 years, trade has changed from major flows between the US and Europe to major flows between Asia and the US.  相似文献   
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