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121.
122.
J. Edward Anderson 《先进运输杂志》1987,21(1):81-84
The choice of fare policy is more flexible in personal rapid transit than in conventional transit and has some unique aspects. The implementation of fare policies as a function of distance are discussed, and, following a discussion of how the fare would be collected in a PRT system, consideration is given to whether the fare should be per person or per vehicle. 相似文献
123.
Category and regression household trip generation analysis techniques were compared and contrasted. The comparative research was facilitated through a discussion that revealed the interchangeability of two methods of calibrating a category model. While the cell mean method is simple to implement, it does not readily yield statistical indexes for comparison with regression models. The general linear model analysis of variance (GLANOVA) readily provides statistical indexes for the comparison of category and regression trip generation models, and it produces identical empirical results to the simpler cell mean approach of calibrating a category model.The empirical comparison supports the widespread use of category models for trip generation analysis in transportation planning studies. It was found that regression and category models yielded equivalent results for typical planning applications at the district level of aggregation. In addition, both techniques estimated overall trip rate with equal accuracy in the calibration phase, and the two approaches were indistinguishable with respect to sample size sensitivity. However, households with extremely large trip rates were underestimated to a greater degree by category models than regression models. This tendency, in turn, resulted in larger calibration coefficients of determination for regression models. Since the cell mean method of calibrating a model is simpler and easier to understand than a regression model representation, category models can be recommended over regression models for planning studies. 相似文献
124.
Bruce E. Marti 《Maritime Policy and Management》1982,9(4):241-250
This paper demonstrates the validity of relative shift technique toward aiding the port geographer/planner in decision-making. The technique can be applied with a minimal of effort and yield diagnostic information concerning port commodity flows. A broad overview of New England's port facilities is presented, and the technique is then applied to an individual port, Boston. 相似文献
125.
Paul E. Kent 《Maritime Policy and Management》1995,22(2):155-170
The international maritime community is concerned about Panama's preparedness to undertake the responsibility of what many consider to be the world's greatest maritime asset, the Panama Canal. In accordance with treaty provisions, the longer within the dominion of the U.S. government and its attendant regulatory framework and policies. To a great extent, Panama's efforts to prepare for the transfer thus far have been driven by its objective of a seamless transfer, whereby the status quo (meaning the Canal's existing institutional and organizational framework and attendant policies and procedures) would be preserved as much as possible. This would assure the maritime community that it can expect the same service and cost standards traditionally enjoyed under the Panama Canal Commission's stewardship. Still of great concern, however, is the continued reliability and productivity of the Canal's labour force; the Canal's reliability and efficient performance in the past is often attributed to its history of harmonious labour management relations. This article addresses some of the critical labour relations issues that will need to be considered even if Panama's status quo objective for the transfer is achieved. 相似文献
126.
Bernhard E. Nickel 《先进运输杂志》1988,22(2):134-153
Dramatic deteriorations in the future development of demographic and socio-economic factors having a decisive impact on public transport demand in 2000 - 2030 are predicted. How can a reasonable public transport service be maintained under these changing conditions? Depending on the entrepreneurial objectives defined individually by each public transport company a range of strategic actions must be taken in the field of offer and performance: Advancing strategies, consolidation strategies and defensive strategies are discussed with the stress laid on improving service in order to attract more ridership. 相似文献
127.
Ira Hirschman Claire Mcknight John Pucher Robert E. Paaswell Joseph Berechman 《Transportation》1995,22(2):97-113
In 1992, the authors carried out a statistical analysis of Triborough Bridge and Tunnel Authority (TBTA) crossings in New York City, to determine the impact of toll increases on traffic volumes and revenue. Using twelve years of monthly time-series data, we developed a set of multiple regression models that estimated traffic volumes on each TBTA bridge and tunnel as a function of the toll level and other explanatory variables. In most cases, the estimated toll elasticities were negative and much less than 1.0 in absolute value; the median toll elasticity for automobiles was found to be –0.10. Our finding that automobile travel demand is highly inelastic with respect to toll rates is consistent with most previous travel demand studies. 相似文献
128.
129.
Igor P. Semiletov Irina I. Pipko Irina Repina Natalia E. Shakhova 《Journal of Marine Systems》2007,66(1-4):204
Climatic changes in the Northern Hemisphere have led to remarkable environmental changes in the Arctic Ocean, which is surrounded by permafrost. These changes include significant shrinking of sea-ice cover in summer, increased time between sea-ice break-up and freeze-up, and Arctic surface water freshening and warming associated with melting sea-ice, thawing permafrost, and increased runoff. These changes are commonly attributed to the greenhouse effect resulting from increased atmospheric carbon dioxide (CO2) concentration and other non-CO2 radiatively active gases (methane, nitrous oxide). The greenhouse effect should be most pronounced in the Arctic where the largest air CO2 concentrations and winter–summer variations in the world for a clean background environment were detected. However, the air–land–shelf interaction in the Arctic has a substantial impact on the composition of the overlying atmosphere; as the permafrost thaws, a significant amount of old terrestrial carbon becomes available for biogeochemical cycling and oxidation to CO2. The Arctic Ocean's role in determining regional CO2 balance has been ignored, because of its small size (only 4% of the world ocean area) and because its continuous sea-ice cover is considered to impede gaseous exchange with the atmosphere so efficiently that no global climate models include CO2 exchange over sea-ice. In this paper we show that: (1) the Arctic shelf seas (the Laptev and East-Siberian seas) may become a strong source of atmospheric CO2 because of oxidation of bio-available eroded terrestrial carbon and river transport; (2) the Chukchi Sea shelf exhibits the strong uptake of atmospheric CO2; (3) the sea-ice melt ponds and open brine channels form an important spring/summer air CO2 sink that also must be included in any Arctic regional CO2 budget. Both the direction and amount of CO2 transfer between air and sea during open water season may be different from transfer during freezing and thawing, or during winter when CO2 accumulates beneath Arctic sea-ice; (4) direct measurements beneath the sea ice gave two initial results. First, a drastic pCO2 decrease from 410 μatm to 288 μatm, which was recorded in February–March beneath the fast ice near Barrow using the SAMI-CO2 sensor, may reflect increased photosynthetic activity beneath sea-ice just after polar sunrise. Second, new measurements made in summer 2005 beneath the sea ice in the Central Basin show relatively high values of pCO2 ranging between 425 μatm and 475 μatm, values, which are larger than the mean atmospheric value in the Arctic in summertime. The sources of those high values are supposed to be: high rates of bacterial respiration, import of the Upper Halocline Water (UHW) from the Chukchi Sea (CS) where values of pCO2 range between 400 and 600 μatm, a contribution from the Lena river plume, or any combination of these sources. 相似文献
130.
分别采用多层次参数扫描(MLPS)算法和模拟退火粒子群优化(SAPSO)算法对并联式混合动力车逻辑门限控制策略的参数进行优化.将优化后的车辆以TEST-CITY-HWY测试循环进行仿真,并将结果与优化前的车辆的仿真结果进行对比.结果表明,经MLPS算法优化后,燃油消耗和HC与NOx排放分别下降了11.98%、6.01%和4.03%,但CO排放增加了25.18%;经SAPSO算法优化后,燃油消耗和HC、CO与NOx排放分别下降了13.61%、9.57%、27.78%和18.53%,且电池荷电状态(SOC)比MLPS优化略高.说明SAPSO算法在混合动力车控制参数优化效果上明显优于MLPS算法. 相似文献