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991.
992.
海滨大桥是江苏省东部沿海地区省道226线上的一座特大型桥梁。抓好桩基施工质量是全桥质量的控制关键。作为大桥建设管理者之一而直接参与了该桥桩基础施工的现场管理,对深水桩、超长桩施工管理有着自己的切身体会和感受。结合该桥桩基施工方案和实施中的具体做法。 相似文献
993.
西江水运主通道通航枢纽建设关键技术研究 总被引:1,自引:0,他引:1
广西西江航运建设发展有限责任公司 《西部交通科技》2006,(1):19-21
文章主要介绍西部项目西江水运主通道通航枢纽建设研究的背景、内容、成果及关键技术,为其他航运枢纽建设提供了设计、决策的依据,其研究成果具有广阔的应用和参考价值。 相似文献
994.
995.
大断面盾构隧道管片设计内力和变形极值分析 总被引:1,自引:0,他引:1
文章以双车道高速公路越江盾构隧道为例,设计了一种10块分管片结构,其分块为1K(18°) 2A (31°) 7B(40°)=360°。对采用匀质圆环和铰接圆环模型模拟装配式管片结构,进行了不同拼装方式下管片结构的内力和变形极值分析,得出了不同模型下管片结构的内力和变形图特征及变化规律。采用匀质圆环模型计算控制最大正负弯矩和最小变形,而采用铰接圆环模型计算控制最小正负弯矩和最大变形以及最大和最小剪力,不同的拼装方式控制不同的内力和变形设计值。 相似文献
996.
This paper presents a multiple discrete-continuous econometric structure to model the daily time-investment decisions of couples
in solo- and joint-discretionary activities incorporating intra-personal and inter-personal inter-dependencies. The empirical
model was estimated using data from the 2000 Bay Area Travel Survey. The results indicate evidence of the positive impact
of vehicle availability on independent activity participation and the negative impacts of the presence of children and mandatory
time investments on the joint discretionary-activity engagement of the spouses. In addition, we also find the mandatory- and
maintenance-activity-participation characteristics of the spouse to influence the discretionary activity choices of individuals.
Finally, the analysis also indicates a strong impact of common unobserved factors on the decisions of couples. From a policy
analysis perspective, these results imply that demand-management actions directly impacting one adult could also result in
changes to the activity patterns of his/her spouse and to changes in joint activity participation characteristics.
Dr. Sivaramakrishnan Srinivasan is an Assistant Professor in the Department of Civil and Coastal Engineering at the University of Florida. His research interests
include travel-behavior analysis, activity-based travel-demand modeling, and the application of advanced econometric methods
for transportation problems.
Dr. Chandra R. Bhat has contributed toward the development of advanced econometric techniques for travel behavior analysis, in recognition of
which he received the 2004 Walter L. Huber Award and the 2005 James Laurie Prize from the American Society of Civil Engineers
(ASCE). 相似文献
997.
Should we abandon activity type analysis? Redefining activities by their salient attributes 总被引:3,自引:0,他引:3
Sean T. Doherty 《Transportation》2006,33(6):517-536
This paper poses a challenge and begins a search. The challenge is to reconsider the usefulness of traditional activity types (“work”, “shopping”, etc.) in the understanding and modelling of travel behaviour. The search is for the more salient attributes of activities that may serve to better explain complex travel behaviours—such as activity scheduling and tour formation. In particular, this paper focuses on explicit measures of the spatial, temporal and interpersonal flexibility of activities, along with several traditional attributes (frequency, duration, involved persons, travel time, and location). Data from a recent in-depth week-long activity scheduling survey was used to define and compare these attributes. Results show that considerable variability in the attributes between and within traditional activity groups is evident. This casts considerable uncertainty on assumptions that statically assign levels of spatial, temporal, and interpersonal flexibility to any given activity type. A Principal Components Analysis further revealed eight new distinct clusters of activities that share like attributes. The relative role of each attribute in each component is examined, and subjective interpretations emerged (e.g., “Long and frequent”, “Space and time flexible” “Social networking”). The implications of these results for future model development and research are discussed. Future research should continue to expand the search for salient attributes and link them more directly to decision processes. 相似文献
998.
The need for acquiring the current-year traffic data is a problem for transport planners since such data may not be available
for on-going transport studies. A method is proposed in this paper to predict hourly traffic flows up to and into the near
future, using historical data collected from the Hong Kong Annual Traffic Census (ATC). Two parametric and two non-parametric
models have been employed and evaluated in this study. The results show that the non-parametric models (Non-Parametric Regression
(NPR) and Gaussian Maximum Likelihood (GML)) were more promising for predicting hourly traffic flows at the selected ATC station.
Further analysis encompassing 87 ATC stations revealed that the NPR is likely to react to unexpected changes more effectively
than the GML method, while the GML model performs better under steady traffic flows. Taking into consideration the dynamic
nature of the common traffic patterns in Hong Kong and the advantages/disadvantages of the various models, the NPR model is
recommended for predicting the hourly traffic flows in that region. 相似文献
999.
以电动汽车仿真软件ADVISOR为基础,根据混合动力汽车的不同工况,分析和建立了串联混合动力电动汽车的一种控制模式——功率跟随控制模式。并且详细分析了功率跟随控制模式在ADVISOR软件中的实现方法。 相似文献
1000.