1. Uncertainty modeling and stability assessment of minimum spanning trees in network designAhmad Hosseini, 2024, original scientific article Abstract: The Minimum Spanning Tree (MST) problem in networks focuses on finding efficient routes, with applications in transportation, logistics, telecommunications, and more. However, catastrophes can make these networks uncertain, requiring robust computational models for decision-making. This paper introduces an uncertainty theory-based model to analyze the stability of MSTs in uncertain networks. By incorporating reliability and risk variables, we assess the robustness of uncertain MSTs (UMSTs) and address the challenge of computing link tolerances, which define the range within which network links can vary without compromising MST optimality. This study proposes computational formulations to systematically calculate these tolerances, offering a more efficient alternative to traditional re-optimization methods.
Keywords: operations research, transportation, sensitivity analysis, uncertainty, reliability
Published in RUNG: 03.12.2024; Views: 145; Downloads: 0
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2. Max-type reliability in uncertain post-disaster networks through the lens of sensitivity and stability analysisAhmad Hosseini, 2024, original scientific article Abstract: The functionality of infrastructures, particularly in densely populated areas, is greatly impacted by natural disasters, resulting in uncertain networks. Thus, it is important for crisis management professionals and computer-based systems for transportation networks (such as expert systems) to utilize trustworthy data and robust computational methodologies when addressing convoluted decision-making predicaments concerning the design of transportation networks and optimal routes. This study aims to evaluate the vulnerability of paths in post-disaster transportation networks, with the aim of facilitating rescue operations and ensuring the safe delivery of supplies to affected regions. To investigate the problem of links' tolerances in uncertain networks and the resiliency and reliability of paths, an uncertainty theory-based model that employs minmax optimization with a bottleneck objective function is used. The model addresses the uncertain maximum reliable paths problem, which takes into account uncertain risk variables associated with links. Rather than using conventional methods for calculating the deterministic tolerances of a single element in combinatorial optimization, this study introduces a generalization of stability analysis based on tolerances while the perturbations in a group of links are involved. The analysis defines set tolerances that specify the minimum and maximum values that a designated group of links could simultaneously fluctuate while maintaining the optimality of the max-type reliable paths. The study shows that set tolerances can be considered as well-defined and proposes computational methods to calculate or bound such quantities - which were previously unresearched and difficult to measure. The model and methods are demonstrated to be both theoretically and numerically efficient by applying them to four subnetworks from our case study. In conclusion, this study provides a comprehensive approach to addressing uncertainty in reliability problems in networks, with potential applications in various fields.
Keywords: Disaster Management, Network Reliability, Stability Analysis, Transportation, Uncertainty
Published in RUNG: 24.11.2023; Views: 1541; Downloads: 6
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7. Importance of pedestrianization for urban regeneration. Assessing new bridge solutions for the Golden Horn : Pedestrianization in Golden HornPinar Özge Gezer, 2020, master's thesis Abstract: The Golden Horn (in Turkish Halic means Gulf or Altın Boynuz "Golden Horn") is a historic inlet of the Bosphorus dividing the city of İstanbul and forming the natural harbor that has sheltered Ottoman and other ships for thousands of years. It is a scimitar-shaped estuary that joins the Bosphorus just at the point where that strait enters the Sea of Marmara, thus forming a peninsula the tip of which is "Old İstanbul".
This thesis work focuses on design proposal for the pedestrian bridge for Golden Horn Dis-trict, which links the royal and later historical peninsula to the rest of the city. The main challenge of the thesis is creation of continuous pedestrian network to guarantee uninter-rupted pedestrian connectivity as well as systematic activation of social and environmental urban regeneration.
Keywords: bridge, pedestrianization, walkability, Golden Horn, historical penninsula, connection, transportation, cultural park, green areas, attraction points, İstanbul, Leonardo Da Vinci
Published in RUNG: 28.02.2020; Views: 4221; Downloads: 119
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