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1.
This paper offers a conceptual exploration of the potential impacts of ICTs on leisure activities and the associated travel. We start by discussing what leisure is and is not. We point out that the boundaries between leisure, mandatory, and maintenance activities are permeable, for three reasons: the multi-attribute nature of a single activity, the sequential interleaving of activity fragments, and the simultaneous conduct of multiple activities (multitasking). We then discuss four kinds of ways by which ICT can affect leisure activities and travel: the replacement of a traditional activity with an ICT counterpart, the generation of new ICT activities (that may displace other activities), the ICT-enabled reallocation of time to other activities, and ICT as a facilitator of leisure activities. We suggest 13 dimensions of leisure activities that are especially relevant to the issue of ICT impacts: location (in)dependence, mobility-based versus stationary, time (in)dependence, planning horizon, temporal structure and fragmentation, possible multitasking, solitary versus social activity, active versus passive participation, physical versus mental, equipment/media (in)dependence, informal versus formal arrangements required, motivation, and cost. The primary impact of ICT on leisure is to expand an individual’s choice set; however whether or not the new options will be chosen depends on the attributes of the activity (such as the 13 identified dimensions), as well as those of the individual. The potential transportation impacts when the new options are chosen are ambiguous.  相似文献   
2.
A 2D advection-dispersion model, already described and validated, has been used to provide information about water trajectories, transit times, transfer factors and transfer functions in the Channel and North Sea, south of 57 ° N.It shows that a fast vein of water moves parallel to the coast and reaches the northern limit of the model in one year. Along the coast, a few dozen kilometers from this vein, transit times increase by 2–4 months.Tidal gyres in the Channel recirculate waters and dissolved elements for about 2 yr, and in all it generally takes 3 yr for a specific discharge made at La Hague to completely leave the area under study.The transfer factor was depicted and found to be of the order of 10−5 m.k.s.One utilization of the transfer function could be to predict the future evolution of water content in the months and years following a discharge in these coastal waters.  相似文献   
3.
From 1986 to 1992, 125Sb released by the nuclear fuel reprocessing plant at La Hague has been used to study the transfer of waters from mid-Channel areas towards the Straits of Dover. Since 1940, these investigations have formed part of the MAST 53 FLUXMANCHE programme and have involved repeated measurements on a Straits of Dover transect. A discussion of the results is presented here which takes into account new information provided by a hydrodynamic model developed in the framework of FLUXMANCHE; it combines knowledge of the monthly fluxes of water trough the Straits of Dover and week-by-week simulation of the 125Sb activities of waters flowing in this aera. It is proposed that soluble radionuclides introduced into the central Channel are transferred towards the Straits of Dover over a time which varies from four to seven months depending on the route taken.  相似文献   
4.
Abstract

In transportation, informal transport refers mainly to the use of paratransit services in the developing world. In this paper we argue that informal travel may include, in addition to mode and users, also other travel pattern elements, such as trip planning, structure, purpose, and destination. Each of these can be placed along an axis ranging from formal manifestations to informal ones, thus creating a ‘formality scale’. Moreover, these elements may be combined in numerous ways, creating a multitude of travel patterns that may be placed all along the formality scale. After providing a definition of formal, semi-formal, and informal travel and characterizing travel patterns according to the formality scale we identify population groups which exemplify semi-formal and informal travel patterns. Next, we analyze the 2009 US National Household Travel Survey, which suggests informal travel may be growing. This leads to a discussion on various factors that might affect travel formality. Most notably, the growing use of information and communication technologies may be shifting travel toward the informal end of the axis. In turn, this might affect trip symmetry, which may result in further effects on the transportation system.  相似文献   
5.
Review: State of teleactivities   总被引:2,自引:0,他引:2  
The investigation of teleactivities and their impacts on travel behavior received much attention in the transportation literature. Toward further teleactivity research, this paper reviews previous research and analyzes the findings regarding the role of Information and Communication Technologies (ICT) in personal activity and travel patterns. This review of about 100 studies of teleactivities impacts maps reviewed studies according to whether the type of personal activity is mandatory, maintenance, or leisure, the nature of the research is conceptual or empirical and, if empirical, tabulates the ICT impact and the modeling approaches. Telecommuting, enabling mandatory personal activities, has been the most investigated teleactivity (by more than 50% of reviewed articles). Teleshopping and several other teleservices (e.g., telebanking), enabling maintenance personal activities, have received less attention in the literature. Teleleisure, enabling discretionary personal activities, has been the least studied. Of the four major direct impacts of ICT on travel, i.e., substitution, complementarity, modification, and neutrality, substitution has been the most prevalent impact for telecommuting, with complementarity most prevalent impact for teleshopping and teleleisure. More recent empirical have applied more advanced modeling approaches.  相似文献   
6.
Moving bottlenecks in highway traffic are defined as a situation in which a slow-moving vehicle, be it a truck hauling heavy equipment or an oversized vehicle, or a long convey, disrupts the continuous flow of the general traffic. The effect of moving bottlenecks on traffic flow is an important factor in the evaluation of network performance. This effect, though, cannot be assessed properly by existing transportation tools, especially when the bottleneck travels relatively long distances in the network.This paper develops a dynamic traffic assignment (DTA) model that can evaluate the effects of moving bottlenecks on network performance in terms of both travel times and traveling paths. The model assumes that the characteristics of the moving bottleneck, such as traveling path, physical dimensions, and desired speed, are predefined and, therefore, suitable for planned conveys.The DTA model is based on a mesoscopic simulation network-loading procedure with unique features that allow assessing the special dynamic characteristics of a moving bottleneck. By permitting traffic density and speed to vary along a link, the simulation can capture the queue caused by the moving bottleneck while preserving the causality principles of traffic dynamics.  相似文献   
7.
Telecommunications accommodate the transmission of information at steadily decreasing costs, especially when compared to transport. This is of growing importance as economies move toward increased reliance on information as an economic, social and political resource. A common notion on the spatial impacts of new telecommunications systems is that they will contribute to the elimination of regional inequalities. Specifically, entry by high-tech industries and information-intensive activities is believed to be facilitated by telecommunications, and in turn, foster development. A preliminary question undelying this notion is whether such systems do in fact create an “equal opportunity space”? Evidence from Israel, supported by findings from other countries, demonstrate that the telephone system, still the back-bone of telecommunications systems, does not offer equal access across space. This holds true for both intea-urban and inter-regional scales. The findings suggest that reduced telecommunications costs do not have a major impact on changing the relative weights of location factors. The interplay of demand, supply and government intervention indicates that the disadvantage of distance will persist in the information era.  相似文献   
8.
9.
. This study examines the impact of telecommuting on passenger vehicle-miles traveled (VMT) through a multivariate time series analysis of aggregate nationwide data spanning 1966–1999 for all variables except telecommuting, and 1988–1998 for telecommuting. The analysis was conducted in two stages. In the first stage, VMT (1966–1999) was modeled as a function of conventional variables representing economic activity, transportation price, transportation supply and socio-demographics. In the second stage, the residuals of the first stage (1988–1998) were modeled as a function of the number of telecommuters. We also assessed the change in annual VMT per telecommuter as well as VMT per telecommuting occasion, for 1998. The models suggest that telecommuting reduces VMT, with 94% confidence. Together with independent external evidence, the results suggest a reduction in annual VMT on the order of 0.8% or less. Even with impacts that small, when informally compared to similar reductions in VMT due to public transit ridership, telecommuting appears to be far more cost-effective in terms of public sector expenditures.  相似文献   
10.
This paper presents an analysis of telecommunications and travel costs for typical business meetings. It is contribution to the debate on the substitutability of telecommunications for travel. An underlying assumption which supports the substitution hypothesis is that the cost of traversing distance through the use of telecommunication is lower than the cost of travelling.This paper addresses the relative cost of telecommunications and travel in conducting interactions. Three factors are assumed to determine these costs: distance, duration of interaction and number of participants. The analysis assumes that cost alone affects choice, and ignores other communication qualities.The relationship between telecommunication and travel costs was tested quantitatively through a case study of typical business meetings in the U.S., based on data from 1988. The results show that travel costs are lower than telecommunication costs for shorter distances, and that the relationship between telecommunications and travel costs differs substantially as a function of number of participants and meeting duration. Because of ongoing rapid changes in the costs of both of these interaction modes, the complex competition between them will continue. The implications of the findings for location decisions and policy-making are discussed.  相似文献   
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