Multi-objective network optimization: models, methods, and applications

There can be an array of planning objectives to consider when identifying alternatives for using, modifying, or restoring natural or built environments. In this respect, multi-objective network optimization models can provide decision support to both managers and users of the system. While there can be an infinite number of feasible solutions to any multi-objective optimization problem in large networks (e.g., urban transportation systems), the efficient ones are usually more desirable in the decision-making process. However, identification of efficient solutions can be challenging in practical applications. To address this issue, this dissertation details mathematical formulations and solution algorithms for a range of real-world planning problems in the context of intelligent transportation systems, vehicle routing problem, natural conservation and landscape connectivity. While the combination of objectives being optimized is unique for each application, the underlying phenomena involves modeling movement between origins and destinations of a networked system. To demonstrate the type of insights that can be achieved using these modeling approaches, the location and number of times solutions appear in different realizations of system and given different solution approaches (e.g., exact and approximate methods) are visualized on network using a commercial geographic information system

Algorithmic Analysis of Intermodal Transport Network

Tato práce je zaměřena na analýzu intermodální dopravní sítě pomocí multikriteriálního algoritmu s ohledem na priority města. Nejprve popisujeme reprezentaci intermodální dopravní sítě. Poté definujeme úlohu analýzy nad danou reprezentací. Jedná se o algoritmickou analýzu, tedy na základě zadané poptávky cestujících vyhodnocujeme klíčové indikátory. Mezi zahrnuté indikátory patří počet přeplněných úseků spojů, doba jízdy všech cestujících a celkové náklady všech cestujících. Cílem analýzy je optimalizovat počet přeplněných úseků dopravní sítě tím, že nabídneme cestujícím alternativní jízdy. Tyto cesty se snaží vyhnout úsekům dopravní sítě, kde jsou spoje přeplněné. Vyhnout se lze vybráním jiného spoje veřejné dopravy, jízdou na kole, nebo využitím taxi služby. Popisujeme multikriteriální algoritmus, který pro každého cestujícího vyhledá vhodnou cestu, přičemž optimalizuje čtyři kritéria: obsazenost vozu, dobu jízdy, cestovní náklady a počet přestupů. Také implementujeme nástroj pro analýzu, který obsahuje tento multikriteriální algoritmus a z nalezených cest vypočítá chtěné klíčové indikátory. Pomocí našeho nástroje provádíme analýzu intermodální dopravní sítě hlavního města Prahy. Při evaluaci námi vygenerované poptávky cestujících dosahujeme snížení počtu přeplněných úseků spojů v intermodální dopravní síti o 79,4 %.This work focuses on the analysis of the intermodal transport network using a multi-criteria algorithm that considers preferences of the city. To perform the analysis, we first describe the representation of the intermodal transport network. Given the representation, we define the intermodal transport network analysis problem with preferences of the city. We aim at algorithmic analysis, which computes key performance indicators using given travel demand. Thus, we provide various key performance indicators, e.g., the number of overcrowded trip segments, the total duration of all passenger journeys, and the total costs of passenger journeys. The goal of the analysis is to optimize the number of overcrowded parts of the public transport network. To achieve the goal, we offer passengers alternative journeys. These journeys try to avoid public transport vehicles with occupancy beyond a certain level of comfort. In other words, a passenger may choose another public transport connection, ride a bike, or use a taxi service. We propose a multi-criteria algorithm that finds a suitable journey for each passenger while optimizing four criteria, i.e., vehicle occupancy, duration, costs, and the number of interchanges. We also implement an analysis tool that includes the multi-criteria algorithm and calculates the required key performance indicators. By using the analysis tool, we perform an analysis using the intermodal transport network of the capital city of Prague. In the evaluation, we achieve the reduction in the number of overcrowded trip segments in the intermodal transport network by 79.4 % on randomly generated travel demand

Generating constrained length personalized bicycle tours

In the context of recreational routing, the problem of finding a route which starts and ends in the same location (while achieving a length between specified upper and lower boundaries) is a common task, especially for tourists or cyclists who want to exercise. The topic of finding a tour between a specified starting and ending location while minimizing one or multiple criteria is well covered in literature. In contrast to this, the route planning task in which a pleasant tour with length between a maximum and a minimum boundary needs to be found is relatively underexplored. In this paper, we provide a formal definition of this problem, taking into account the existing literature on which route attributes influence cyclists in their route choice. We show that the resulting problem is NP-hard and devise a branch-and-bound algorithm that is able to provide a bound on the quality of the best solution in pseudo-polynomial time. Furthermore, we also create an efficient heuristic to tackle the problem and we compare the quality of the solutions that are generated by the heuristic with the bounds provided by the branch-and-bound algorithm. Also, we thoroughly discuss the complexity and running time of the heuristic

Route Planning in Transportation Networks

We survey recent advances in algorithms for route planning in transportation networks. For road networks, we show that one can compute driving directions in milliseconds or less even at continental scale. A variety of techniques provide different trade-offs between preprocessing effort, space requirements, and query time. Some algorithms can answer queries in a fraction of a microsecond, while others can deal efficiently with real-time traffic. Journey planning on public transportation systems, although conceptually similar, is a significantly harder problem due to its inherent time-dependent and multicriteria nature. Although exact algorithms are fast enough for interactive queries on metropolitan transit systems, dealing with continent-sized instances requires simplifications or heavy preprocessing. The multimodal route planning problem, which seeks journeys combining schedule-based transportation (buses, trains) with unrestricted modes (walking, driving), is even harder, relying on approximate solutions even for metropolitan inputs.Comment: This is an updated version of the technical report MSR-TR-2014-4, previously published by Microsoft Research. This work was mostly done while the authors Daniel Delling, Andrew Goldberg, and Renato F. Werneck were at Microsoft Research Silicon Valle

Algorithm Engineering for Realistic Journey Planning in Transportation Networks

Diese Dissertation beschäftigt sich mit der Routenplanung in Transportnetzen. Es werden neue, effiziente algorithmische Ansätze zur Berechnung optimaler Verbindungen in öffentlichen Verkehrsnetzen, Straßennetzen und multimodalen Netzen, die verschiedene Transportmodi miteinander verknüpfen, eingeführt. Im Fokus der Arbeit steht dabei die Praktikabilität der Ansätze, was durch eine ausführliche experimentelle Evaluation belegt wird

Book of abstracts of the 24th Euro Working Group on Transportation Meeting

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Open Business Model of COVID-19 Transformation of an Urban Public Transport System: The Experience of a Large Russian City

Dialectics, or developmental transformation, would eventually cause any system to change. The level and depth of these changes vary and depend on the power of external influence and system reservation mechanisms. The art of managing system processes consists of two main aspects. The first aspect involves the sagacity of managers and predicting general environmental change trends (and their impacts on the managed system). The second involves adjusting to these trends, maximizing possible benefits, and minimizing the negative manifestations of this process. Innovation plays an important role, contributing to system transformations with maximal effect and minimal loss. Public transport systems are important elements in cities, as they provide spatial mobility for at least half of the citizens of a city who cannot use individual transportation. Modern urbanization and peculiarities of the social–economic statuses of many citizens contribute to the fact that organized public transportation is unprofitable. The low solvency of citizens who use public transportation services means that passenger transport systems do not work with enough profitability. As a result, governing institutions often choose to subsidize unprofitable transporter activities, thereby prolonging the functioning of unprofitable routes. This is possible only in conditions of sustainability (in regards to a non-optimal system), when the environment is calm, and its negative impact is low. “Black swans” (according to N. Taleb) are bifurcation factors that break the sustainability of non-optimal system. Urban public transport (UPT) of a large Russian city, Tyumen, experienced it in 2020, in connection with the COVID-19 lockdown. The sharp decrease in population mobility in Tyumen, in 2020–2021, caused the need for a complete transformation of the transport service system. However, managers did not want to fundamentally change a system that consensually suited most counterparties. The search for new balances in a system that demands transformation is one way for sustainable provision. This article looks at the transformation and sustainability of a UPT system in the large Russian city of Tyumen, under conditions affected by the negative impact of COVID-19. Results of a comparative (i.e., pre-crisis (2019) and crisis (2020)) Pareto analysis of the contributions of different UPT routes are presented. Transformation of the structure of the UPT route system can overcome the “crisis” COVID-19 period and minimize its financial-economic costs. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This research was funded by the Russian Ministry of Education and Science, grant number 0825-2020-0014, 2020–2022. «New patterns and solutions for the functioning of urban transport systems in the paradigm “Transition from owning a personal car to mobility as a service”»