221,679 research outputs found
Route repetition and route retracing: effects of cognitive aging
No full textRetracing a recently traveled route is a frequent navigation task when learning novel routes or exploring unfamiliar environments. In the present study we utilized virtual environments technology to investigate age-related differences in repeating and retracing a learned route. In the training phase of the experiment participants were guided along a route consisting of multiple intersections each featuring one unique landmark. In the subsequent test phase, they were guided along short sections of the route and asked to indicate overall travel direction (repetition or retracing), the direction required to continue along the route, and the next landmark they would encounter. Results demonstrate age-related deficits in all three tasks. More specifically, in contrast to younger participants, the older participants had greater problems during route retracing than during route repetition. While route repetition can be solved with egocentric response or route strategies, successfully retracing a route requires allocentric processing. The age-related deficits in route retracing are discussed in the context of impaired allocentric processing and shift from allocentric to egocentric navigation strategies as a consequence of age-related hippocampal degeneration. - See more at: http://journal.frontiersin.org/Journal/10.3389/fnagi.2012.00007/abstract#sthash.xK4Htsfy.dpu
A Portfolio Theory of Route Choice
No full textAlthough many individual route choice models have been proposed to incorporate travel time variability as a decision factor, they are typically still deterministic in the sense that the optimal strategy requires choosing one particular route that maximizes utility. In contrast, this study introduces an individual route choice model where choos- ing a portfolio of routes instead of a single route is the best strategy for a rational traveler who cares about both journey time and lateness when facing stochastic net- work conditions. The model is then tested with GPS data collected in metropolitan Minneapolis-St. Paul, Minnesota. Our data suggest strong correlation among link speed when analyzing morning commute trips. There is no single dominant route (de- fined here as a route with the shortest travel time for a 15 day period) in 18% of cases when links travel times are correlated. This paper demonstrates that choosing a port- folio of routes could be the rational choice of a traveler who wants to optimize route decisions under variability.Transportation planning, route choice, travel behavior, link performance
The secret is to follow your nose: route path selection and angularity
No full textThis paper presents the results of an experiment in which route-choice decisions made by
subjects at road-junctions are recorded. It will then demonstrate that a route can be expressed
as the sum of the individual decisions made or as the sum of all possible decisions available
(i.e. potential choices) during a journey. The relationship between these two values will be
compared statistically indicating that the decisions made at road-junctions correlate more
strongly with maximum angles of incidence of road-center-lines leading from a junction
than to mean or minimum angles. One interpretation of this phenomenon is that subjects
appear to be attempting to conserve linearity throughout their journey. Since any theory
based upon the conservation of angular linearity appears to be refuted by certain, informal
observations of subjects traversing urban grids, the first theory put forward in this paper is
then modified to account for this particular case. The final hypothesis presented in this paper
is based upon acts of rule-based decision-making combining principles of the conservation
of linearity whilst minimising the angular difference between bearings. The two key bearings
are those of the direction of potential route choices compared to the perceived bearings of
the wayfinding goal as judged from sequential instances of the observer's location. This
theory of modified angular conservation is called 'The British Library Theory'.
In (Conroy, 2001) it was demonstrated that the most popular routes from a sample
(as calculated using string-matching techniques) also appeared to be more 'linear'. This observation
reproduces similar findings made in (Golledge, 1995). The question that these observations
prompt is what route choices are individuals making at road junctions such that their
actions result in this apparent conservation of route linearity? Therefore, in this paper a
method is proposed for the determination of route choice decisions made at consecutive
road junctions over the duration of a single journey. This method employs a measure of
angular deviation (from a straight line or direction) and uses this to develop a cumulative
measure for an individual's entire journey, based upon the summation of all choices made at
every junction encountered along the route.
The hypothesis that this method was developed to test is that an individual subject
will follow as straight a route as possible with minimal angular deviation (from a straight
line) on condition that this choice always approximates the direction of their final destination.
Another way of stating this hypothesis is that essentially people 'follow their noses'
whilst navigating through an environment
A heuristic model of bounded route choice in urban areas
No full textThere is substantial evidence to indicate that route choice in urban areas is complex cognitive process, conducted under uncertainty and formed on partial perspectives. Yet, conventional route choice models continue make simplistic assumptions around the nature of human cognitive ability, memory and preference. In this paper, a novel framework for route choice in urban areas is introduced, aiming to more accurately reflect the uncertain, bounded nature of route choice decision making. Two main advances are introduced. The first involves the definition of a hierarchical model of space representing the relationship between urban features and human cognition, combining findings from both the extensive previous literature on spatial cognition and a large route choice dataset. The second advance involves the development of heuristic rules for route choice decisions, building upon the hierarchical model of urban space. The heuristics describe the process by which quick, 'good enough' decisions are made when individuals are faced with uncertainty. This element of the model is once more constructed and parameterised according to findings from prior research and the trends identified within a large routing dataset. The paper outlines the implementation of the framework within a real-world context, validating the results against observed behaviours. Conclusions are offered as to the extension and improvement of this approach, outlining its potential as an alternative to other route choice modelling frameworks
Shortest path or anchor-based route choice: a large-scale empirical analysis of minicab routing in London
No full textUnderstanding and modelling route choice behaviour is central to predicting the formation and propagation of urban road congestion. Yet within conventional literature disagreements persist around the nature of route choice behaviour, and how it should be modelled. In this paper, both the shortest path and anchor-based perspectives on route choice behaviour are explored through an empirical analysis of nearly 700,000 minicab routes across London, United Kingdom. In the first set of analyses, the degree of similarity between observed routes and possible shortest paths is established. Shortest paths demonstrate poor performance in predicting both observed route choice and characteristics. The second stage of analysis explores the influence of specific urban features, named anchors, in route choice. These analyses show that certain features attract more route choices than would be expected were individuals choosing route based on cost minimisation alone. Instead, the results indicate that major urban features form the basis of route choice planning – being selected disproportionately more often, and causing asymmetry in route choice volumes by direction of travel. At a finer scale, decisions made at minor road features are furthermore demonstrated to influence routing patterns. The results indicate a need to revisit the basis of how routes are modelled, shifting from the shortest path perspective to a mechanism structured around urban features. In concluding, the main trends are synthesised within an initial framework for route choice modelling, and presents potential extensions of this research
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Securing route optimisation in NEMO
No full textThird International Symposium on Modeling and Optimization in Mobile, Ad Hoc,and Wireless Networks. 4-6 April 2005. Riva del Garda, Trentino, ItalyThe network mobility (NEMO) basic support protocol enables mobile networks to change their point of attachment to the Internet, while preserving established sessions of the nodes within the mobile network. When only a nonnested mobile network is considered, the so-called triangle routing is the main problem that should be faced. In mobile IPv6, the route optimisation mechanism solves this problem, and the return routability mechanism aims to limit the security concerns originated because of the route optimisation. Nowadays return routability is considered a weak solution (i.e., based on strong assumptions). In this article we explore different approaches to route optimisation in NEMO and we devise how to adapt some of the terminal mobility solutions to a NEMO environment, where, as we propose, a delegation of signalling rights from the mobile network node to the mobile router is necessary.Publicad
Travel Time Reliability and Quality Assessment of a Route Set through Route Aggregation
No full textConventional travel time reliability assessment focuses either on reliability on route level or the determination of the valuation of reliability in route choice. However, a connection between origin and destination usually consists of multiple routes, thereby providing the option to choose. This study assesses the reliability and quality of the aggregate of the route set of an OD-pair as having (an) alternative(s) can compensate for deterioration of a single route. Furthermore, it is unknown how the perception of reliability of the aggregate of available routes depends on the travel behavior of the user. An adapted Logsum is proposed as aggregation method and the perceived reliability is investigated for multiple scenarios. It is determined that the Logsum is an appropriate measure for aggregation, but should be used combined with the ratio between number of alternatives and dispersion. The perceived reliability analysis showed that informing travelers and variable departure times can significantly improve the user perceived travel time reliability.Transport & PlanningCivil Engineering and Geoscience
Route choice responses to variable road user charges and traffic information
No full textThis study investigates the drivers' route choice in response to variable road user charges and traffic information. Firstly, this study investigates the effects of
information concerning traffic conditions on drivers' route choice behaviour and the way in which drivers evaluate the value of information concerning delay time. Secondly, drivers' response to different types of variable road user charges and their sensitivity to these road user charges are explored. Thirdly, the way that the uncertain information influence drivers' behaviours are also analysed. Finally, this study investigates the extent to which socio-economic characteristics influence drivers' responses to road user charge and to the information concerning traffic conditions and charges.
The traffic information is provided via VMS and related to the expected delay time. Three types of the variable road user charges are applied: fixed charges; timebased
charges; and delay time-based charges. Three SP surveys are conducted to collect data. The main survey is conducted in Leeds and Seoul, and the additional survey is conducted in Leeds. Logit models are used for analysing the main SP
survey data. The repeated measurement problem in the main survey data is corrected using the jackknife method and Kocur's method. A regression method is used in the analysis of the additional survey data. Some results reveal that Utility Theory was not enough to explain the results. Therefore, Prospect Theory is applied to the results and is found to give a satisfactory explanation.
The results indicate that drivers are less likely to choose a route characterised by recurrent delays and as the length of delay reported on their usual route increases drivers value delay time information more highly than free travel time and become increasingly sensitive to delay time as it increases. The delay thresholds in this study are 10 minute for the normal delay time and 15 minutes for the extra delay
time on VMS
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