86,966 research outputs found
Delay and disruption management in local public transportation via real-time vehicle and crew re-scheduling: a case study
No full textLocal public transport companies, especially in large cities, are facing every day the problem of managing delays and small disruptions. Disruption management is a well-established practice in airlines and railways. However, in local public transport the approaches to these problems have followed a different path, mainly focusing on holding and short-turning strategies not directly associated with the driver scheduling. In this paper we consider the case of the management of urban surface lines of Azienda Trasporti Milanese (ATM) of Milan. The main issues are the service regularity as a measure of the quality of service, and the minimization of the operational costs due to changes in the planned driver scheduling. We propose a simulation-based optimization system to cope with delays and small disruptions that can be effectively used in a real-time environment and takes into account both vehicle and driver scheduling. The proposed approach is tested on real data to prove its actual applicability
A personalized walking bus service requiring optimized route decisions: A real case
No full textWe address the design of the lines of a Walking Bus service according to a new paradigm, where children are picked up at home. The scarcity of accompanying persons together with the limit on the length of the deviations from the shortest itinerary of each child make the problem different from the traditional school bus and walking bus design. We propose an arc-based model, a path-based model tackled by column generation, and a heuristic procedure. Solution approaches are tested on a set of real and realistic instances. Real instances refer to the case study of a primary school in Italy
Shear-resistant hydrogels to control permeability of porous tubular scaffolds in vascular tissue engineering
No full textDelay Management in Public Transportation: Service Regularity Issues and Crew Re-scheduling
No full textIn this paper, we propose a decision support tool to assist a local public transportation company in tackling service delays and small disruptions. We discuss different ways to assess and improve the regularity of the service, and we propose a simulation based optimization system that can be effectively used in a real-time environment taking into account both vehicle and driver shifts. In particular, we describe a tabu-search procedure for the online vehicle scheduling optimizing the regularity of the service and a column generation approach for the consequential crew re-scheduling minimizing the driver extra-time. As a case study, we analyze the management of urban surface lines of Azienda Trasporti Milanese (ATM) of Milan. In the last part of the paper we report a detailed analysis of the experimental phase showing the effectiveness of the proposed approach
Distribution and mixing of a liquid bolus in pleural space
No full textDistribution and mixing time of boluses with labeled albumin in pleural space of anesthetized, supine rabbits were determined by sampling pleural liquid at different times in various intercostal spaces (ics), and in cranial and caudal mediastinum. During sampling, lung and chest wall were kept apposed by lung inflation. This was not necessary in costo-phrenic sinus. Here, 10 min after injection, lung inflation increased concentration of labeled albumin by 50%. Lung inflation probably displaces some pleural liquid cranio-caudally, increasing labeled albumin concentration caudally to injection point (6th ics), and decreasing it cranially. Boluses of 0.1-1 ml did not preferentially reach mediastinal regions, as maintained by others. Time for an approximate mixing was similar to 1 h for 0.1 ml, and similar to 30 min for 1 ml. This relatively long mixing time does not substantially affect determination of contribution of lymphatic drainage through stomata to overall removal of labeled albumin from 0.3 ml hydrothoraces lasting 3 h [Bodega, F., Agostoni, E., 2004. Contribution of lymphatic drainage through stomata to albumin removal from pleural space. Respir. Physiol. Neurobiol. 142, 251-263]
Designing Pedibus Lines: a Path Based Approach
No full textWe study the problem of designing walking school bus lines (Pedibus) limiting the deviation with respect to the shortest path for each child, with the objective of minimizing the number of accompanying persons and the perceived risk of the selected trajectories. The problem is formulated using a path model and a column generation approach is proposed. Computational experiments compare the lower bounds and the solutions of the proposed approach with the arc model and a simple heuristic proposed in a previous wor
Parallel Translations from the English Wiktionary
No full text<p>Parallel translations from English words and expressions as extracted from the English Wiktionary (database version of 2018-06-01). The data includes 2,169,063 different entries from the translation of 149,530 English words and expressions in 2,358 languages (with much variation in vocabulary size among languages: 931 languages have only one entry and German, the largest language after English, 97,091 entries). Data is offered in a tabular textual format, and all entries include (a) a unique ID, (b) a concept ID referring to the source English word, (c) a description string with the English source and a short definition (such as “dictionary/publication that explains the meanings of an ordered list of words“), (d) a language ID from the Glottolog catalog, (e) the text of the translation as given in the Wiktionary, and (f) an extra field holding complementary information, when available (such as phonetic transcription of the text, noun gender, etc.). Data is also offer in a set of files (tabular textual files, bibtex sources, and JSON metadata) following the Cross-Linguistic Data Formats (CLDF), a specification designed to allow the exchange of cross-linguistic data.</p>
<p>Code for the extraction is available at http://github.com/tresoldi/wiktionary_parser and a longer description in a blog post of our group, at https://calc.hypotheses.org/?p=32</p>
Long-term ERT monitoring data analysis to set slope instability attention thresholds based on water level fluctuations
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