Search results for "Travel"
showing 10 items of 402 documents
An Exact Algorithm for the Quadratic Assignment Problem on a Tree
1989
The Tree QAP is a special case of the Quadratic Assignment Problem (QAP) where the nonzero flows form a tree. No condition is required for the distance matrix. This problem is NP-complete and is also a generalization of the Traveling Salesman Problem. In this paper, we present a branch-and-bound algorithm for the exact solution of the Tree QAP based on an integer programming formulation of the problem. The bounds are computed using a Lagrangian relaxation of this formulation. To solve the relaxed problem, we present a Dynamic Programming algorithm which is polynomially bounded. The obtained lower bound is very sharp and equals the optimum in many cases. This fact allows us to employ a redu…
The Spanning Tree based Approach for Solving the Shortest Path Problem in Social Graphs
2016
Nowadays there are many social media sites with a very large number of users. Users of social media sites and relationships between them can be modelled as a graph. Such graphs can be analysed using methods from social network analysis (SNA). Many measures used in SNA rely on computation of shortest paths between nodes of a graph. There are many shortest path algorithms, but the majority of them suits only for small graphs, or work only with road network graphs that are fundamentally different from social graphs. This paper describes an efficient shortest path searching algorithm suitable for large social graphs. The described algorithm extends the Atlas algorithm. The proposed algorithm so…
Developing and Integrating Advanced Movement Features Improves Automated Classification of Ciliate Species
2015
Recent advances in tracking technologies such as GPS or video tracking systems describe the movement paths of individuals in unprecedented details and are increasingly used in different fields, including ecology. However, extracting information from raw movement data requires advanced analysis techniques, for instance to infer behaviors expressed during a certain period of the recorded trajectory, or gender or species identity in case data is obtained from remote tracking. In this paper, we address how different movement features affect the ability to automatically classify the species identity, using a dataset of unicellular microbes (i.e., ciliates). Previously, morphological attributes a…
Is Participation in Tourism Market an Opportunity for Everyone? Some Evidence from Italy
2014
Exploring the main determinants of tourism participation at national and international level, the paper investigates if there are differences in tourism consumption behavior among Italian families which reflect disparities in their standard of living. To achieve this a Heckman model has been used on a huge sample of Italian households over the period 1997-2007. Results show that participation in the tourism market is strongly affected by the personal characteristics of individuals and that tourism consumption is an income sensitive good. The analysis reveals that tourism is generally a luxury good reflecting the disparities in the standard of living among Italian families. We have found tha…
Does Urban Security Modulate Transportation Choices and Travel Behavior of Citizens? A National Study in the Dominican Republic
2020
Introduction: Traditionally, the scientific literature on urban and transportation dynamics addresses many topics, but the security-related outcomes of users remain a pending issue, especially in emerging countries and their cities. Nevertheless, recent evidence suggests that, especially in developing countries, security issues may influence people’s decision-making in the choice of transport means, daily urban-trip patterns and road behaviors of users. Objective: The purpose of this study was to explore the relationships between the perceived security (in both urban environments and public transport systems) and the daily-travel behavior and trip patterns of the Dominican Republic populati…
The role of travel motivations and social media use in consumer interactive behaviour: a uses and gratifications perspective
2020
This paper explores the influence of travel motivations and the gratification provided by social media in consumer stickiness to social media, intention to create user-generated content, and electronic word of mouth (eWOM) review adoption. The study follows a mixed-methods approach. First, a concept mapping study was undertaken to identify the main travel motivations and the gratifications provided by social media when consumers search for information on tourism destinations. A second study using structural equation modelling and SmartPLS 3.2.7 with a sample of 401 heavy users of social media showed the relationships between individual travel motivations and gratifications provided by socia…
Prefazione a Emmanuel Iduma, Lo sguardo di uno sconosciuto
2020
By introducing Emmanuel Iduma's travelogue across Africa, which he traveled from East to West as a member of the Trans-African project "Invisible Borders", the Preface also explains the significance and urgency of launching a new African Literature Series for the respected Milan-based independent press Francesco Brioschi Editore. The Series publishes the works of African writers from the younger generations.
The Effect of Advanced Traveller Information Systems (ATIS) on public transport demand and its uncertainty
2009
Advanced Traveller Information Systems (ATISs) include a broad range of advanced computer and communication technologies. These systems are designed to provide transit riders pre-trip and real-time information, to make better informed decisions regarding their mode of travel, planned routes and travel times. ATISs include in-vehicle displays, terminal or wayside based information centres, information by phone or mobile and internet. In this article, a Stated Preference survey has been carried out in order to know the preferences of public transport’s customers related to different ATISs and their willingness to pay in Palermo. An ordered probit demand model has been calibrated to determine …
Why do older drivers reduce driving? Findings from three European countries
2003
The objective of this study was to find out the reasons, which lead drivers to reduce their driving in varying cultural settings. Data on the prevalence of reduced driving, the reasons for and factors associated with reduced driving were obtained from Finnish, German and Italian home-dwelling active drivers (n=710) aged 55 and older. The subjects were interviewed in autumn 1995 at their homes with a standardized questionnaire as a part of the European project Keeping the Elderly Mobile: Technology to Meet Their Outdoor Mobility Needs. In the Finnish and German samples 62% and in the Italian sample 44% of the active drivers stated that they had reduced their driving. These persons drove fewe…
Urban public transport optimization by bus ways: a neural network-based methodology
2007
This paper describes an approach for planning the introduction of bus lanes into the urban road network, that has been applied to the urban area of Palermo. The proposed modelling tool adopts a multi-agent objective function expressing the trade-off between the interests of diverse stakeholders: the generalized transport cost for car drivers and the travel time for public transport users. The reaction of car traffic to a certain planning scenario has been simulated by the DUE assignment technique and the positive impact of the modal shift on the objective function has been tackled by attaching a suitable weight to the time saving for bus passengers. The rise in the bus travel speed, owing t…