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171.
Transportation specialists, urban planners, and public health officials have been steadfast in encouraging active modes of
transportation over the past decades. Conventional thinking, however, suggests that providing infrastructure for cycling and
walking in the form of off-street trails is critically important. An outstanding question in the literature is how one’s travel
is affected by the use of such facilities and specifically, the role of distance to the trail in using such facilities. This
research describes a highly detailed analysis of use along an off-street facility in Minneapolis, Minnesota, USA. The core
questions addressed in this investigation aim to understand relationships between: (1) the propensity of using the trail based
on distance from the trip origin and destination, and (2) how far out of their way trail users travel for the benefit of using
the trail and explanatory factors for doing so. The data used in the analysis for this research was collected as a human intercept
survey along a section of an off-street facility. The analysis demonstrates that a cogent distance decay pattern exists and
that the decay function varies by trip purpose. Furthermore, we find that bicyclists travel, on average, 67% longer in order
to include the trail facility on their route. The paper concludes by explaining how the distance decay and shortest path versus
taken path analysis can aid in the planning and analysis of new trail systems.
Kevin J. Krizek is an Associate Professor of Planning and Design at the University of Colorado where he directs the Active Communities/Transportation Research Group. His research interests include land use-transportation policies and programs that influence household residential location decisions and travel behavior. He has published in the areas of transportation demand management, travel behavior, neighborhood accessibility, and sustainable development. He earned a Ph.D. in Urban Design and Planning and M.S.C.E. from the University of Washington in Seattle. His master’s degree in planning is from the University of North Carolina at Chapel Hill and his undergraduate degree is from Northwestern University. Ahmed El-Geneidy is a Post-Doctoral research fellow at the Department of Civil Engineering, University of Minnesota and Humphrey Institute of Public Affairs. El-Geneidy’s research interests include transit operations, travel behavior, land use and transportation planning, and accessibility/mobility measures in urban areas. He earned B.S. and M.S. degrees from the Department of Architectural Engineering at the University of Alexandria, Egypt, and continued his academic work at Portland State University, where he received a Graduate GIS Certificate and earned a Ph.D. in Urban Studies from Nohad A. Toulan School of Urban Studies and Planning. Kristin Thompson was a research assistant with ACT and currently works for Metro Transit in Minneapolis, Minnesota. 相似文献
Ahmed El-GeneidyEmail: |
Kevin J. Krizek is an Associate Professor of Planning and Design at the University of Colorado where he directs the Active Communities/Transportation Research Group. His research interests include land use-transportation policies and programs that influence household residential location decisions and travel behavior. He has published in the areas of transportation demand management, travel behavior, neighborhood accessibility, and sustainable development. He earned a Ph.D. in Urban Design and Planning and M.S.C.E. from the University of Washington in Seattle. His master’s degree in planning is from the University of North Carolina at Chapel Hill and his undergraduate degree is from Northwestern University. Ahmed El-Geneidy is a Post-Doctoral research fellow at the Department of Civil Engineering, University of Minnesota and Humphrey Institute of Public Affairs. El-Geneidy’s research interests include transit operations, travel behavior, land use and transportation planning, and accessibility/mobility measures in urban areas. He earned B.S. and M.S. degrees from the Department of Architectural Engineering at the University of Alexandria, Egypt, and continued his academic work at Portland State University, where he received a Graduate GIS Certificate and earned a Ph.D. in Urban Studies from Nohad A. Toulan School of Urban Studies and Planning. Kristin Thompson was a research assistant with ACT and currently works for Metro Transit in Minneapolis, Minnesota. 相似文献
172.
Virginia R. Ferritto 《WMU Journal of Maritime Affairs》2016,15(2):353-380
Presenteeism research has only recently extended from a construct capturing lost productivity due to attending work despite health issues to a construct representing students’ perceived academic performance. Aligning with presenteeism’s prevalent research paradigm, the pioneering studies used health-related issues to measure presenteeism. In contrast, this study used the Presenteeism and Perceived Academic Performance (PPAP) Scale, which the researcher developed for this study. The PPAP Scale comprises aspects of student behavior that support academic performance. This study filled gaps in the literature by investigating presenteeism as a concept associated with students’ perceived academic performance, measured with the PPAP Scale, and factors specific to maritime education. The factors investigated were self-identified by the study respondents, in sufficient numbers to support statistical analysis, as favorably (i.e., cruise and license/maritime instruction) or negatively (i.e., mandatory regimental activity, taps, morning or afternoon formations, and watch) impacting their academic performance. This study found no statistical evidence to suggest the level of presenteeism, measured with the PPAP Scale, among the study’s sample of license students is associated with factors perceived to favorably or negatively impact academic performance. Additional insight can be gained from license student participants’ responses to the study’s open-ended questions (e.g., a perceived imbalance between time available to allocate to their academics and time needed to fulfill regimental responsibilities). 相似文献
173.
W. Jacobs C. Reynaerts S. Andries S. van den Akker N. Moonen D. Lamoen 《Journal of Marine Science and Technology》2016,21(4):758-766
In a previous study, it was found that cargo tank operations like cleaning and venting, lead to higher cargo vapor concentrations around the ship’s superstructure. Can wind tunnel experiments confirm these findings? Is there an improvement when using higher outlets at high velocities compared to lower outlets with a low outlet velocity? Is there a relation between relative wind speed and measured concentration? These questions were investigated in the Peutz wind tunnel. By using a tracer gas for the wind tunnel experiments, concentration coefficients have been calculated for various settings. The study shows that using high-velocity outlets is an efficient way to keep concentrations as low as possible. The only exception is for relative wind directions from the bow. In this last case using a manhole as ventilation outlet leads to lower concentrations. With increasing wind speeds the building downwash effect resulted in higher concentration coefficients near the main deck. This study confirms our on-board measurements and suggests the lowering of the ventilation inlet of the accommodation, so that the high-velocity outlet can be used safely at all times. 相似文献
174.
Ibrahim S. Seddiek 《Journal of Marine Science and Technology》2016,21(3):493-500
Strategies of fuel consumption onboard ships are of one of the crucial issues in marine shipping industry. Many of the relevant authorities maritime domain gave great interesting to that issue, either through research that discussed the impact of marine fuel consumption on the environment and economy of ships or through practical experiments’ that are made by marine engine manufacturers. Over the years, many solutions have been put forward to overcome this problem while maintaining the amount of goods transported globally at the same transfer rate and ship speed. The present paper sheds light on many of the methods used currently to reach this purpose. It is explained that applying a certain fuel-saving strategy will rely on some of the factors, especially the type of ship. Mainly two methods including: shore-side power and cold out of heat strategies have been investigated regarding adaption, economic, and environmental issues in case of applying onboard high-speed passenger ships. 相似文献
175.
For the complex structure and vibration characteristics of the seat and cab system of truck, there is no reliable theoretical model for the suspensions design at present, which seriously restricts the improvement of ride comfort. In this paper, a 4 degree-of-freedom seat-cab coupled system model was presented; using the mechanism modeling method, its vibration equations were built; then, by the tested cab suspensions excitations and seat acceleration response, its parameters identification mathematical model was established. Combining the tested signals and a simulation model with the parameters identification mathematical model, a new method of hybrid modeling of seat-cab coupled system was presented. With a practical example of seat and cab system, the parameters values were identified and validated by simulation and test. The results show that the model and method proposed are correct and reliable, and lay a good foundation for the optimal design of seat suspension and cab suspensions to improve ride comfort. 相似文献
176.
Equivalent consumption minimization strategy (ECMS) is a widely used energy management method in the battery equipped bio-sources energy system, in which an equivalence factor is adopted to weigh the two kinds of energy, usually fuel and electricity. The regulation of the equivalence factor will affect not only the fuel consumption but also the battery's state of charge (SOC) sustainability, which results great influence upon the energy management of the system. In this paper, a new perspective of treating the relationship between the equivalence factor and instantaneous fuel consumption as well as instantaneous electricity consumption as a first-order dynamic system is proposed, thus the relationship between the equivalence factor and SOC is deduced as a second-order dynamic system. Based on the perspective, a linear second-order Active Disturbance Rejection Control (ADRC) is employed to regulate the equivalence factor, which can estimate and compensate, in real-time, disturbances in the system from input-output information only. An engine waste heat recovery energy network constructed by <engine> - <power turbine> - <Organic Rankine Cycle System> - <electric cooling system> - <battery> - <Integrated starter and Generator> is selected as the research object, simulation verifications upon 11 different driving cycles based on the simulation platform established by GT-SUITE software are conducted to test the fuel-saving capability and SOC self-sustainability by the proposed approach with a same set of tuning parameters. Simulation results indicate that both the fuel-saving capability and the SOC self-sustainability can be ensured by the active control of equivalent factor with a same set of tuning parameters upon all the 11 driving cycles, demonstrating a great adaptability of the control parameters. 相似文献
177.
The aim of this work is the design of an algorithm for on-board determination of the actual capacity of a lithium iron phosphate (LFP) cathode-based lithium-ion battery for electric vehicle applications. The presented approach is based on the detection of the predominant aging mechanisms (in terms of loss of lithium and loss of active material in both electrodes) by determining the single electrode voltage curves. The information related to the characteristic length and position of the voltage plateaus, which can be gathered during battery operation, can be used to obtain the actual aging state of the cells. The length of the plateaus depends on the respective position that the voltage curves of the single electrodes have in relation to each other. Relating the change of the plateau characteristics to the possible aging mechanisms allows the determination of the actual battery aging state in terms of total cell capacity. The work presents a possible implementation of an algorithm for capacity determination based on the described methodology. The algorithm is validated with various differently aged LFP cells. Furthermore, the work discusses the ability of the method to detect the actual battery capacity if the characteristics of only part of the quasi-OCV (open circuit voltage) curve are detected. Achieved accuracy and existing limitations are described and discussed in detail. 相似文献
178.
J. Han O. Heo M. Park S. Kee M. Sunwoo 《International Journal of Automotive Technology》2016,17(3):483-491
For robust vision-based forward collision warning (FCW) and autonomous emergency braking (AEB) systems, not only reliable detection performance including high detection rate and low false positives but also accurate measurement output of a target vehicle is required. Especially, in order to reduce false alarm or activation of FCW/AEB systems, the systems require the precise measurement output of a target object, such as position, velocity, acceleration, and time-to-collision (TTC). In this study, we developed a measurement estimation algorithm of a target vehicle using a monocular camera. This method estimates two cases of vehicle widths for a target vehicle by using the detected lane information and a pin-hole camera model. After that, the position, velocity, acceleration, and TTC of a target vehicle are estimated by using a Kalman filter for the each estimated vehicle width. To improve robustness, the both estimation results using the detected lane information and the pinhole camera model are fused. This estimation algorithm was evaluated and compared with the state-of-the-art technology. As a result, the proposed measurement output estimation method can improve the performance of the FCW/AEB systems. 相似文献
179.
This study explores the relationships between adoption and consideration of three travel-related strategy bundles (travel
maintaining/increasing, travel reducing, and major location/lifestyle change), linking them to a variety of explanatory variables.
The data for this study are the responses to a fourteen-page survey returned by nearly 1,300 commuting workers living in three
distinct San Francisco Bay area neighborhoods in May 1998. We first identified patterns of adoption and consideration among
the bundles, using pairwise correlation tests. The test results indicate that those who have adopted coping strategies continue
to seek for improvements across the spectrum of generalized cost, but perhaps most often repeating the consideration of a
previously-adopted bundle. Furthermore, we developed a multivariate probit model for individuals’ simultaneous consideration
of the three bundles. It is found that in addition to the previous adoption of the bundles, qualitative and quantitative Mobility-related
variables, Travel Attitudes, Personality, Lifestyle, Travel Liking, and Sociodemographics significantly affect individual
consideration of the strategy bundles. Overall, the results of this study give policy makers and planners insight into understanding
the dynamic nature of individuals’ responses to travel-related strategies, as well as differences between the responses to
congestion that are assumed by policy makers and those that are actually adopted by individuals.
Sangho Choo is a Research Associate at The Korea Transport Institute. His research interests include travel demand modeling, travel survey methods with GPS, and travel behavior modeling. Patricia L. Mokhtarian is a professor of Civil and Environmental Engineering, chair of the interdisciplinary Transportation Technology and Policy MS/PhD program, and Associate Director for Education of the Institute of Transportation Studies at the University of California, Davis. She has been modeling travel behavior and attitudes for more than 30 years. 相似文献
Patricia L. Mokhtarian (Corresponding author)Email: |
Sangho Choo is a Research Associate at The Korea Transport Institute. His research interests include travel demand modeling, travel survey methods with GPS, and travel behavior modeling. Patricia L. Mokhtarian is a professor of Civil and Environmental Engineering, chair of the interdisciplinary Transportation Technology and Policy MS/PhD program, and Associate Director for Education of the Institute of Transportation Studies at the University of California, Davis. She has been modeling travel behavior and attitudes for more than 30 years. 相似文献
180.
Khandker M. Nurul Habib 《Transportation》2011,38(1):123-151
The paper presents a modeling framework for dynamic activity scheduling. The modeling framework considers random utility maximization
(RUM) assumption for its components in order to capture the joint activity type, location and continuous time expenditure
choice tradeoffs over the course of the day. The dynamics of activity scheduling process are modeled by considering the history
of activity participation as well as changes in time budget availability over the day. For empirical application, the model
is estimated for weekend activity scheduling using a dataset (CHASE) collected in Toronto in 2002–2003. The data set classifies
activities into nine general categories. For the empirical model of a 24-h weekend activity scheduling, only activity type
and time expenditure choices are considered. The estimated empirical model captures many behavioral details and gives a high
degree of fit to the observed weekend scheduling patterns. Some examples of such behavioral details are the effects of time
of the day on activity type choice for scheduling and on the corresponding time expenditure; the effects of travel time requirements
on activity type choice for scheduling and on the corresponding time expenditure, etc. Among many other findings, the empirical
model reveals that on the weekend the utility of scheduling Recreational activities for later in the day and over a longer
duration of time is high. It also reveals that on the weekend, Social activity scheduling is not affected by travel time requirements,
but longer travel time requirements typically lead to longer-duration social activities. 相似文献