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1.
The aim of this paper is to investigate the behaviour of water transportation company stock returns in the U.S. stock exchanges from 1985 to 1994 in order to determine whether the systematic risk of this industry is different from that of the 'average' company in the market, whether it has changed over the ten year period, over bull and bear market conditions, and whether there is a firm 'size' effect in the industry. In the context of the Capital Asset Pricing Model (Capm), we find that the systematic risk of the shipping industry return is not different from that of the 'average' company. It is also found that the covariance of water transportation companies with respect to the overall stock market return did not change over the ten year period although it appears that it has changed over normal upward/downward market movements. There is also reasonable evidence that the intercept of the equation might have changed over normal upward/downward market movements. Finally, we document contradictory evidence regarding the size effect; during the period 1985-1989 we find small companies to have significantly higher returns and risk while during the period 1990-1994 medium size companies tend to have higher risk than small and large firms, which is not however compensated by higher returns. 相似文献
2.
Y. Hattori K. Asano N. Iwama T. Shigematsu 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(4):299-311
This report describes a decelerating driver-model expressed by driving mode transition in car-following situations. The assumptions for constructing the model are that decelerating strategy of a driver is classified into several simple driving modes and that a driver changs his driving modes based on his perceptible characteristics and experiential rules. Deceleration action is divided into three states; following, standing and braking, which are applied to the model. The model has two paths for driver's decelerating action, one of which is selected by the driver based on the perceptible characteristics and experiential rules. The suitability of the model has been experimentally verified. 相似文献
3.
N. Docquier P. Fisette H. Jeanmart 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2007,45(6):505-524
This article presents a multidisciplinary approach of railway pneumatic suspension modelling: both multibody and pneumatic aspects are taken into account. The work aims at obtaining a realistic model of the secondary suspension and coupling it with a multibody model of a train. Various components of the pneumatic circuit such as bellows, tanks, pipes and valves are taken into account. The article focuses on the bellow-pipe-tank subsystem for which several modelling approaches are presented and compared. Differences between differential and algebraic models are highlighted, and an application-dependent choice between them is suggested. A complete model of the pneumatic circuit is then obtained and coupled with a multibody model of the train. As a result, the behaviour of a suburban train equipped with a pneumatic secondary suspension is analysed, in particular undesired oscillating motions which affect the comfort. Topological modifications and improvements of the suspension are also investigated and discussed. 相似文献
4.
Major highway reconstruction can cause significant disruptions to existing travel patterns and economic activity. Reducing these impacts on travelers, shippers, businesses and residents requires that innovative and effective transportation management actions be developed and implemented. This paper reports the major findings and recommendations of a research study on managing transportation during highway, reconstruction. The primary objectives of the study were
The recommended process consists of five chronological phases, each composed of many tasks having related focuses within the overall process. Each task is designed to contribute to the common objective of seeing that an effective transportation management plan for mitigating travel impacts throughout the project corridor is successfully realized. This process was formulated on the basis of information collected on 25 highway reconstruction projects throughout the United States by way of site visits, direct meetings with project personnel, requests for documentation, and phone interviews. 相似文献
| to investigate and document the critical interrelationships among state-of-the-art reconstruction and scheduling techniques, traffic accommodation strategies, construction quality control measures, and project planning and evaluation processes, and |
| to formulate and recommend a corridor transportation management process that can be used to develop, implement and evaluate a transportation management plan of strategies to mitigate the corridor-wide impacts of major highway reconstruction. |
5.
An interactive modelling approach is developed to solve the practical problem of bus route network design. Possible bus routes are identified with facilities which can be located. Zones or pairs of zones in the urban area are identified with customers who will be allocated to the established facilities. It is shown that the classical Set Covering Problem is useful under the assumption of fixed demand; the Simple Plant Location Problem is effective under the assumption of demand which is sensitive to the level of bus service provided. 相似文献
6.
Claudio Mazzoleni Hans Moosmüller Hampden D. Kuhns Robert E. Keislar Peter W. Barber Djordje Nikolic Nicholas J. Nussbaum John G. Watson 《Transportation Research Part D: Transport and Environment》2004,9(6):477-496
Carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO) emission factors (EFs) are measured with a commercial vehicle emissions remote sensing system (VERSS) during a large-scale vehicle exhaust emissions study in Las Vegas. Particulate matter (PM) EFs are simultaneously measured for individual vehicles with a newly developed PM-VERSS based on ultraviolet backscatter light detection and ranging (Lidar). The effectiveness of CO and HC EFs as proxy for NO and PM EFs for spark-ignition vehicles is evaluated. Poor correlations were found between EFs for pollutants on an individual vehicle basis indicating that high EFs for one or more pollutants cannot be used as a predictor of high EFs for other pollutants. Stronger functional relationships became evident after averaging the EF data in bins based on rank-order of a single pollutant EF. Low overlap between the highest 10% emitters for CO, HC, NO, and PM was found. These results imply that for an effective reduction of the four pollutants, inspection and maintenance (I/M) programs, including clean screening, should measure all four pollutants individually. Fleet average CO and HC concentrations determined by gaseous VERSS were compared with fleet average CO and HC concentrations measured at low-idle and at high-idle during local I/M tests for spark-ignition vehicles. The fleet average CO concentrations measured by I/M tests at either idle were about half of those measured by remote sensing. The fleet average high-idle HC concentration measured by I/M tests was about half of that measured by VERSS while low-idle I/M and VERSS HC average concentrations were in better agreement. For a typical vehicle trip, most of the fuel is burned during non-idle conditions. I/M measurements collected during idling conditions may not be a good indicator of a vehicle’s potential to be a high emitter. VERSS measurements, when the vehicle is under a load, should more effectively identify high emitting vehicles that have a large contribution to the mobile emissions inventory. 相似文献
7.
H. M. Abdul Aziz Nicholas N. Nagle April M. Morton Michael R. Hilliard Devin A. White Robert N. Stewart 《Transportation》2018,45(5):1207-1229
This study estimates a random parameter (mixed) logit model for active transportation (walk and bicycle) choices for work trips in the New York City (using 2010–2011 Regional Household Travel Survey Data). We explored the effects of traffic safety, walk–bike network facilities, and land use attributes on walk and bicycle mode choice decision in the New York City for home-to-work commute. Applying the flexible econometric structure of random parameter models, we capture the heterogeneity in the decision making process and simulate scenarios considering improvement in walk–bike infrastructure such as sidewalk width and length of bike lane. Our results indicate that increasing sidewalk width, total length of bike lane, and proportion of protected bike lane will increase the likelihood of more people taking active transportation mode This suggests that the local authorities and planning agencies to invest more on building and maintaining the infrastructure for pedestrians. Further, improvement in traffic safety by reducing traffic crashes involving pedestrians and bicyclists, will increase the likelihood of taking active transportation modes. Our results also show positive correlation between number of non-motorized trips by the other family members and the likelihood to choose active transportation mode. The model would be an essential tool to estimate the impact of improving traffic safety and walk–bike infrastructure which will assist in investment decision making. 相似文献
8.
9.
Melissa N. Errend Lisa Pfeiffer Erin Steiner Marie Guldin Amanda Warlick 《Coastal management》2018,46(6):564-586
AbstractThe West Coast Groundfish Trawl Catch Share Program was designed to achieve multiple economic goals and objectives, including increasing net benefits, profitability, flexibility, and utilization of harvest allocations. In this article, we leverage seven years of comprehensive cost and earnings data to evaluate progress towards these goals with a focus on harvesters. Our assessment shows that five years post-implementation, net benefits to the nation have doubled, and indicators of productivity and profitability have increased. The fleet that targets Pacific whiting has seen the largest gains, due in part to increases in total allowable catch and the elimination of the race-to-fish. However, increased revenues have not been realized to the degree that was expected for harvesters targeting non-whiting groundfish, partly due to lower than predicted consolidation and relatively low quota utilization. Economic outcomes indicate that tradeoffs exist between certain objectives of the program, specifically between achieving full utilization and flexibility for harvesters. Results are discussed in the context of the design and evaluation of catch share programs for diverse, multispecies fisheries. 相似文献
10.
A new approach for improving the performance of freight train timetabling for single-track railways is proposed. Using the idea of a fixed-block signaling system, we develop a matrix representation to express the occupation of inter- and intra-station tracks by trains illustrating the train blocking time diagram in its entirety. Train departure times, dwell times, and unnecessary stopping are adjusted to reduce average train travel time and single train travel time. Conflicts between successive stations and within stations are identified and solved. A fuzzy logic system is further used to adjust the range of train departure times and checks are made to determine whether dwell times and time intervals can be adjusted for passenger and freight trains at congested stations to minimize train waiting times. By combining manual scheduling expertise with the fuzzy inference method, timetable efficiency is significantly improved and becomes more flexible. 相似文献