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851.
Roy Van Den Berg Peter W. De Langen Paul C.J. Van Zuijlen 《WMU Journal of Maritime Affairs》2017,16(3):421-438
A review of seven large landlord port authorities around the world reveals a notable diversity of pricing structures. While port authorities increasingly act as commercial undertakings, port pricing often seems to be not driven by commercial considerations. In this paper, we argue that ports can be regarded as “business ecosystems” with multiple users. This provides a valuable perspective on pricing and raises the question of whether ports can be regarded as two-sided markets. We argue this is not the case. The business ecosystem perspective provides a basis for deducing seven pricing principles for port authorities that are detailed in the paper and illustrated with cases these principles. These pricing principles are broadly follow a direct user pays approach; capture value from “non-core” tenants; price aggressively for activities with a high strategic value; differentiate pricing based on price elasticity and connectivity improvements; maximize revenue from long-term lease agreements, price port dues competitively; critically consider differentiation of charges based on environmental performance; and finally use incentives to align interests of terminal operators and shipping lines. We conclude that the ecosystem perspective is central to the understanding of pricing decisions of port authorities and that various pricing issues deserve more attention. 相似文献
852.
Modeling intermodal equilibrium for bimodal transportation system design problems in a linear monocentric city 总被引:2,自引:0,他引:2
Zhi-Chun Li William H.K. Lam S.C. Wong 《Transportation Research Part B: Methodological》2012,46(1):30-49
This paper investigates the intermodal equilibrium, road toll pricing, and bus system design issues in a congested highway corridor with two alternative modes - auto and bus - which share the same roadway along this corridor. On the basis of an in-depth analysis of the demand and supply sides of the bimodal transportation system, the mode choice equilibrium of travelers along the continuum corridor is first presented and formulated as an equivalent variational inequality problem. The solution properties of the bimodal continuum equilibrium formulation are analytically explored. Two models, which account for different infrastructure/system regulatory regimes (public and private), are then proposed. In the public regulatory model, the road toll location and charge level are simultaneously optimized together with the bus service fare and frequency. In the private regulatory model, the fare and frequency of bus services, which are operated by a profit-driven private operator, are optimized for exogenously given toll pricing schemes. Finally, an illustrative example is given to demonstrate the application of the proposed models. Sensitivity analysis of residential/household distribution along the corridor is carried out together with a comparison of four different toll pricing schemes (no toll, first best, distance based, and location based). Insightful findings are reported on the interrelationships among modal competition, market regulatory regimes, toll pricing schemes, and urban configurations as well as their implications in practice. 相似文献
853.
This paper suggests using a proportional hazard model to predict personal income, for the purpose of imputing missing income
data in household travel surveys. The model has a hazard function that comprises two multiplicative components: (1) a non-parametric
baseline hazard function that is dependent only on the income level and (2) a function that is dependent only on the other
personal attributes of the survey respondents (excluding income). To estimate and validate the model, data is drawn from a
travel characteristics survey conducted in Hong Kong in year 2001. The model is found to have a much higher accuracy when
compared with a conventional ordered probit model based on the assumption that the logarithm of income is normally distributed.
C.·O. Tong is an Associate Professor at the Department of Civil Engineering, The University of Hong Kong. He received his B.Sc. (Eng.) degree from the University of Hong Kong, M.Sc. (Transportation Engineering) degree from Leeds University and Ph.D. degree from Monash University. His research interests are in transport demand modeling and dynamic network modeling. Jackie K. L. Lee worked as a Research Assistant at the Department of Civil Engineering, The University of Hong Kong during the period from March 2004 to April 2005. She received her B.Eng. and M.Eng. degrees in Civil Engineering from the Hong Kong Polytechnic University. She is a Chartered Engineer and is also Corporate Members of the Hong Kong Institution of Engineers and the Institution of Structural Engineers. 相似文献
C. O. TongEmail: |
C.·O. Tong is an Associate Professor at the Department of Civil Engineering, The University of Hong Kong. He received his B.Sc. (Eng.) degree from the University of Hong Kong, M.Sc. (Transportation Engineering) degree from Leeds University and Ph.D. degree from Monash University. His research interests are in transport demand modeling and dynamic network modeling. Jackie K. L. Lee worked as a Research Assistant at the Department of Civil Engineering, The University of Hong Kong during the period from March 2004 to April 2005. She received her B.Eng. and M.Eng. degrees in Civil Engineering from the Hong Kong Polytechnic University. She is a Chartered Engineer and is also Corporate Members of the Hong Kong Institution of Engineers and the Institution of Structural Engineers. 相似文献
854.
无论是军船还是民船,船体及主要结构构件表面的点腐蚀对于船舶结构强度和安全性都有较大的破坏作用.文中采用系列非线性有限元计算研究了点腐蚀对于低碳钢板极限抗压强度的影响,模型中计及板初始缺陷的影响,详细讨论了板和点腐蚀物理、几何特性的变化对于板极限承载能力的作用.研究发现在众多影响因素中(例如点腐蚀的直径和深度、板的柔度系数等),点腐蚀密集度指标DOP对于板的极限承载能力有主要和直接的影响.此外,在腐蚀环境恶劣的情况下,厚低碳钢板的使用不一定如预期的那样能延长其使用期限. 相似文献
855.
The methodology to obtain the non-linear roll damping from decay tests is very old. It has been proposed by Froude in the 19th century and used from then on. Behind it there is a quadratic model [θ│θ│] for the damping and a subsequent equivalent linearization. Probably all model basin in the world follows this approach to assess the damping from a decay test. This is well documented and so is the methods to get the p1-p2 coefficients. This is very general in the sense that in principle,it could be applied t... 相似文献
856.
Design of an energy management strategy for parallel hybrid electric vehicles using a logic threshold and instantaneous optimization method 总被引:2,自引:0,他引:2
Y.- J. Huang C.- L. Yin J.- W. Zhang 《International Journal of Automotive Technology》2009,10(4):513-521
A novel parallel hybrid electric vehicle (PHEV) configuration consisting of an extra one-way clutch and an automatic mechanical
transmission (AMT) is taken as the study subject of this paper. An energy management strategy (EMS) combining a logic threshold
approach and an instantaneous optimization algorithm is developed for the investigated PHEV. The objective of this EMS is
to achieve acceptable vehicle performance and drivability requirements while simultaneously maximizing engine fuel economy
and maintaining the battery state of charge (SOC) in its rational operation range at all times. Under the MATLAB/Simulink
environment, a computer simulation model of the studied PHEV is established using the bench test results. Simulation results
for the behavior of the engine, motor, and battery illustrate the potential of the proposed control strategy in terms of fuel
economy and in keeping the deviations of SOC at a low level. 相似文献
857.
B. K. Han M. K. Cho C. Kim C. H. Lim J. J. Kim 《International Journal of Automotive Technology》2009,10(4):469-474
An efficient multibody dynamic model was developed to predict the vibrating transmitted gear forces of loaded and unloaded
pairs of helical gears simultaneously at all speeds. The model can also calculate the bearing forces of a manual transmission
that, in turn, may be converted to rattling noises. The bending of meshing gear teeth and torsional flexibility of transmission
shafts were considered and embodied effectively in the multibody dynamic model by calculating the tooth bending stiffness
and adding a torsion spring on a shaft section between two gears, respectively. The reactive forces on teeth and bearings
were calculated and compared using three different models that were developed for this study — an equivalent model, a rigid-body
model, and a frequency-based model. The equivalent model took only 58% computation time, compared to the frequency-based method,
even though the two showed very similar results. 相似文献
858.
S. Y. Kim H. C. Choi W. J. Won S. Y. Oh 《International Journal of Automotive Technology》2009,10(1):103-113
Because the overall driving environment consists of a complex combination of the traffic Environment, Vehicle, and Driver
(EVD), Advanced Driver Assistance Systems (ADAS) must consider not only events from each component of the EVD but also the
interactions between them. Although previous researchers focused on the fusion of the states from the EVD (EVD states), they
estimated and fused the simple EVD states for a single function system such as the lane change intent analysis. To overcome
the current limitations, first, this paper defines the EVD states as driver’s gazing region, time to lane crossing, and time
to collision. These states are estimated by enhanced detection and tracking methods from in- and out-of-vehicle vision systems.
Second, it proposes a long-term prediction method of the EVD states using a time delayed neural network to fuse these states
and a fuzzy inference system to assess the driving situation. When tested with real driving data, our system reduced false
environment assessments and provided accurate lane departure, vehicle collision, and visual inattention warning signals. 相似文献
859.
T. J. Kim H. Y. Kim B. C. Hwang H. J. Kang C. Kim 《International Journal of Automotive Technology》2009,10(5):611-618
There are three sub-processes associated with the assembly of an automobile transmission: heat fitting, shrink fitting, and
combination fitting. In the heat fitting stage, the gear is heated to a specified temperature and then squeezed towards the
outer diameter of the shaft. The stress of the heat-fitted gear depends on the yield strength of the gear. In the shrink fitting
process, the gear is typically squeezed towards the shaft at room temperature using a press. An alternate method, known as
warm shrink fitting, heats the already warm gear and safely squeezes it toward the shaft. The warm shrink fitting process
for automobile transmission parts is becoming more commonplace, but the additional heating can cause the dimensions of the
assembled parts (shaft/gear) to change with respect to both the outer diameter and the profile of the gear. As a result, there
may be additional noise and vibration between gears. To address these problems, we analyzed the warm shrink fitting process
using the contact pressure caused by fitting interference between the outer diameter of the shaft and the inner diameter of
the gear, fitting temperature, and the profile tolerance of the gear as design parameters. In this study, a closed form equation
for predicting the contact pressure and fitting load is proposed. This equation is used to develop an optimization technique
for the warm shrink fitting process. The reliability of the model was verified using experimental results measured in the
field, and FEM with thermal-structural coupled field analysis. Actual loads measured in the field showed good agreement with
the results obtained by theoretical and finite element analysis, and expansion of the outer diameters of the gears agreed
well with the results. 相似文献
860.
In order to plan bus operations, it is necessary for transit planners to understand what factors may influence travelers’ choice of buses for travels within a city. The proposed method involves various scenarios of a hypothetical bus operation which was rated by a group of individuals. Analysis of Covariance technique is employed to analyze people's sensitivities to their perceived levels of bus service characteristics. The technique involves:
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testing for the significant effects of varying levels of service characteristics upon people's intentions to use bus service, and
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assessing differences among various population segments in their sensitivity patterns towards bus service characteristics.