Towards a Testbed for Dynamic Vehicle Routing Algorithms

Since modern transport services are becoming more flexible, demand-responsive, and energy/cost efficient, there is a growing demand for large-scale microscopic simulation platforms in order to test sophisticated routing algorithms. Such platforms have to simulate in detail, not only the dynamically changing demand and supply of the relevant service, but also traffic flow and other relevant transport services. This paper presents the DVRP extension to the open-source MATSim simulator. The extension is designed to be highly general and customizable to simulate a wide range of dynamic rich vehicle routing problems. The extension allows plugging in of various algorithms that are responsible for continuous re-optimisation of routes in response to changes in the system. The DVRP extension has been used in many research and commercial projects dealing with simulation of electric and autonomous taxis, demand-responsive transport, personal rapid transport, free-floating car sharing and parking search

Low Visibility: The Fate of Air Traffic Control Privatization

This paper assesses plans to create an independent air traffic control corporation. While the plans being considered don't seem to offer the benefits that could result from privatization (the possible downsides are not being noted here), they also do not offer obvious resolutions to the problems currently faced by the air traffic control system. Since the specifics of a proposal are not currently available, it is not possible to provide a comprehensive assessment of its merits. However, any such proposal will not offer many of the benefits often claimed by advocates of privatization. There also do not appear to be any obvious fixes to the problems faced by the current system as a result of going the route of limited privatization.Notwithstanding a creditable safety record, the Federal Aviation Administration is under fire for mismanagement, particularly in the field of technology modernization. The airline trade association "Airlines for America" ("A4A") and its member carriers are calling for separation of the FAA's air traffic control ("ATC") operations into some kind of independent corporation.The chairman of the Committee on Transportation and Infrastructure of the U.S. House of Representatives, Rep. Bill Shuster (R-PA), has announced his intention to offer a plan resting on some questionable principles, to be discussed below.The appeals for reform typically reflect a yearning for system improvement, a lack of specifics, and a dearth of supporting arguments or data. Dorothy Robyn (2015) of the Brookings Institution noted that "a jaw-droppingly flawed variant on corporatization" has attracted support.It is possible a new air navigation service provider ("ANSP") could provide better service at reduced cost, but thus far no evidence for such a reform in the U.S. has been put forward, nor has any detailed plan been proposed

QOBJ modeling: A new approach in discrete event simulation

This paper deals with a new discrete event simulation modeling concept, calledqobj, which comes from two well-known paradigms:objects andqueuing networks. The first provides important conceptual tools for model organization, while the second one allows for nice visualization of models' internal state and processes. Thanks to the integration of these two paradigms, theqobj concept allows the suppression of several dichotomies characterizing current simulation modeling approaches. For instance,qobj allows the description of system elements which are both mobile and able to do processing, and allows the dynamic instantiation of static and mobile elements during simulation. The design of lift group models for an industrial project illustrates the main features of theqobj concep

A window into learning: case studies of online group communication and collaboration

The two case studies presented explore the potential offered by in‐depth qualitative analysis of students’ online discussion to enhance our understanding of how students learn. Both cases are used to illustrate how the monitoring and moderation of online student group communication can open up a ‘window into learning’, providing us with new insights into complex problem‐solving and thinking processes. The cases offer examples of students’ ‘thinking aloud’ while problem‐solving, showing how and why they arrived at particular outcomes and the underlying thought processes involved. It is argued that these insights into students’ learning processes can in turn offer us the opportunity to adapt our own teaching practice in order to achieve a better pedagogical ‘fit’ with the learning needs of our students; for example, through a more precise or more timely intervention. It is also suggested that looking through this ‘window’ enables us to concentrate our assessment more closely on the process of task completion, rather than focusing solely on the end product

Quality and quantity of service in lift groups

This research was focused on quality of service experienced by passengers in lift systems where multiple cars are sharing same shafts (multi car lift systems) and destination control. These modern lift systems have opportunities and constraints for control algorithms arising by existing and additional quality of service criteria. These additional criteria have rarely been considered in existing literature, control algorithms or traffic analysis. The overall aim of the research was to determine and analyse existing and new quality of service criteria for destination control systems and multi car lift systems in terms of traffic handling and developing lift control concepts considering these criteria. Therefore, the impact on passengers’ quality of service was reviewed using psychology of waiting principles. Detailed definition and analysis was done for reverse journeys in destination control systems and departure delays with a focus on multi car lift systems. To develop and analyse control algorithms known event based traffic simulation, round trip time calculation and Monte Carlo simulation were extended and applied. Traffic control algorithms and concepts were developed to improve passenger experience when using lifts. Additional to dispatching algorithms equations for improved lift kinematics and controlled stopping distances were derived to reduce departure delays in multi car lift systems. Possible improvements were shown in case studies. Compared to traditional lift systems, special opportunities and constraints of a circulating multi car lift system in traffic handling were explored and analysed. New cycle time calculations for shuttle and local group applications were developed. Results were provided using case studies, and necessary control concepts were addressed. With the results of this research, better understanding and assessments of multi car lift systems and destination controls are possible. The traffic control algorithms explored help to build better lift controllers, considering passengers perception. The introduced traffic analysis methods for circulating multi car lift systems support lift planning