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1 – 10 of over 22000Chris Cassir, Michael G H Bell and Jan-Dirk Schmöcker
This paper describes and extends the game theoretic approach to network vulnerability assessment. The basic idea is to set up a game between the network users who are trying to…
Abstract
This paper describes and extends the game theoretic approach to network vulnerability assessment. The basic idea is to set up a game between the network users who are trying to minimise their expected travel time by choice of route and a network tester who is trying to penalise the users most by degrading a link through capacity reduction leading to congestion. The method therefore finds the worst possible location for a link degradation, taking re-routing options into account (an upper, lower bound of impact). The original game identifies the weakest link for routes between an OD pair in the network. Two variations are introduced in this paper in order to determine the weak links for a specific origin or a specific destination and for the whole network. All three game variations are tested on a small network in Leicester and the results are presented.
Alan Nicholson, Jan-Dirk Schmöcker, Michael G H Bell and Yasunori Iida
The objective of this paper is to give an overview of various reliability concepts that have been developed in the last decades. The paper first summarises various indicators that…
Abstract
The objective of this paper is to give an overview of various reliability concepts that have been developed in the last decades. The paper first summarises various indicators that have been developed in order to measure the reliability of a network and then looks at techniques to calculate these indicators. The usefulness and limitations of the different indicators is discussed. The paper suggests that there is no single perfect indicator but that the choice of indicator and technique depends on several factors, including the viewpoint of the analyst and the type and range of interventions being considered. In order to assess the impact of incidents the authors propose to distinguish between three types of intervention, namely “benevolent”, “neutral” or random, and “malevolent”. Also discussed is why the provision of up-to-date information to the traveller has a central role to play when trying to minimise the impact of an incident.
Michael G H Bell, Jan-Dirk Schmoecker, Yasunori Iida and William H K Lam
The importance of the adverse impacts of network degradation has stimulated substantial international research interest in transport network reliability, that is, the ability of…
Abstract
The importance of the adverse impacts of network degradation has stimulated substantial international research interest in transport network reliability, that is, the ability of degraded transport networks to cope with travel demand. Most of the recent research effort has focused on the reliability of urban passenger transport networks, in terms of the probability that the network will deliver a required standard of performance. This situation is characterised by high levels of congestion, a dense road network, and quantifiable probability of degradation of the network. Outside major urban centres, the situation is very different. The main dominant consideration in transport network infrastructure provision is accessibility - linking urban centres, providing regional coverage, and basic levels of accessibility for the non-urban community and economy. The network is sparse, congestion is not a significant issue, and access to essential community services and to markets is the major driving force underlying network development. In this context, the vulnerability of the network is perhaps more important than ‘reliability’. This paper develops the concept of network vulnerability. It begins by reviewing the current state of research into network reliability, then proposes extensions and adaptations to the reliability concepts that are more appropriate for strategic-level multi-modal transport systems. Several alternative definitions for vulnerability are proposed. The paper also discusses the development of algorithmic and visualisation tools that may be used to identify specific ‘weak spots’ in a network, where failure of some part of the transport infrastructure would have the most serious effects on access to specific locations and on overall system performance. Finally, the paper describes potential applications of network vulnerability concepts, and proposes directions for further research.
There is significant amount of literature tackling different issues related to the port industry. The present chapter focuses on a single business unit of seaports aiming at the…
Abstract
There is significant amount of literature tackling different issues related to the port industry. The present chapter focuses on a single business unit of seaports aiming at the documentation of works related to container terminals.
An effort to review, collect and present the majority of the works present in the last 30 years, between 1980 and 2010, has been made in order to picture the problems dealt and methods used by the authors in the specific research field. To facilitate the reader, studies have been grouped under five categories of addressed problems (productivity and competitiveness, yard and equipment utilization, equipment scheduling, berth planning, loading/unloading) and four modelling methodologies (mathematics and operations research, management and economics, simulation, stochastic modelling).
The analysis shows that most works focus on productivity and competitiveness issues followed by yard and equipment utilisation and equipment scheduling. In reference to the methodologies used managerial and economic approaches lead, followed by mathematics and operations research.
In reference to future research, two fields have been identified where there is scope of significant contribution by the academic community: container terminal security and container terminal supply chain integration.
The present chapter provides the framework for researchers in the field of port container terminals to picture the so far works in this research area and enables the identification of gaps at both research question and methodology level for further research.
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