scholarly journals Smart Transit Dynamic Optimization and Informatics

2021 ◽  
Author(s):  
Hamid Reza Sabarshad

With the popularity of Big Data and urban informatics, there is increasing interest in ways to use real time data to improve transportation system operations. In many real-wold applications, demand is revealed dynamically over time, and consequently the routes are determined dynamically as well. In this thesis, contributions are made to several key components of a “smart” transit system framework where dynamic operations are driven by real time information. The first component is in dynamic routing and pricing of a fleet of vehicles. A new dynamic dial-a-ride policy is introduced that features non-myopic pricing based on optimal tolling of queues to fit with the multi-server queueing approximation method. By including social optimal pricing, the social welfare of the resulting system outperforms a pricing policy based on the marginal cost increase of a passenger over a range of test instances. In the examples tested, improvements in social welfare of the non-myopic pricing over the myopic pricing were in the 20% - 31% range. The second component is in the informatics. Effective dynamic optimization of a system (routing, scheduling, fare setting, etc.) requires effective short term prediction of traveler/customer arrival using real-time data. Several recent methods for arrival process prediction, both offline and online, are investigated using real taxi data from New York. An experiment is conducted using the same data set to draw comparisons for arrival process modeling, suggesting that the temporal seasonal factors method from Ihlers et al. (2006) is more effective as an offline approach and the IntGARCH method from Matteson et al. (2011) is more effective as an online approach. The third component investigated is in the prepositioning of idle vehicles. Vehicles that are positioned at locations that take into account future demand can lead to reduced wait times for passengers and improved level of service. A dynamic relocation model is proposed that includes queueing delay to approximate the congestion effect of future demand. A linear problem is formulated based on Marianov and Serra’s (2002) work. By varying customer arrivals, the approach provides a new managerial tool to find the optimal service level.

2021 ◽  
Author(s):  
Hamid Reza Sabarshad

With the popularity of Big Data and urban informatics, there is increasing interest in ways to use real time data to improve transportation system operations. In many real-wold applications, demand is revealed dynamically over time, and consequently the routes are determined dynamically as well. In this thesis, contributions are made to several key components of a “smart” transit system framework where dynamic operations are driven by real time information. The first component is in dynamic routing and pricing of a fleet of vehicles. A new dynamic dial-a-ride policy is introduced that features non-myopic pricing based on optimal tolling of queues to fit with the multi-server queueing approximation method. By including social optimal pricing, the social welfare of the resulting system outperforms a pricing policy based on the marginal cost increase of a passenger over a range of test instances. In the examples tested, improvements in social welfare of the non-myopic pricing over the myopic pricing were in the 20% - 31% range. The second component is in the informatics. Effective dynamic optimization of a system (routing, scheduling, fare setting, etc.) requires effective short term prediction of traveler/customer arrival using real-time data. Several recent methods for arrival process prediction, both offline and online, are investigated using real taxi data from New York. An experiment is conducted using the same data set to draw comparisons for arrival process modeling, suggesting that the temporal seasonal factors method from Ihlers et al. (2006) is more effective as an offline approach and the IntGARCH method from Matteson et al. (2011) is more effective as an online approach. The third component investigated is in the prepositioning of idle vehicles. Vehicles that are positioned at locations that take into account future demand can lead to reduced wait times for passengers and improved level of service. A dynamic relocation model is proposed that includes queueing delay to approximate the congestion effect of future demand. A linear problem is formulated based on Marianov and Serra’s (2002) work. By varying customer arrivals, the approach provides a new managerial tool to find the optimal service level.


We have real-time data everywhere and every day. Most of the data comes from IoT sensors, data from GPS positions, web transactions and social media updates. Real time data is typically generated in a continuous fashion. Such real-time data are called Data streams. Data streams are transient and there is very little time to process each item in the stream. It is a great challenge to do analytics on rapidly flowing high velocity data. Another issue is the percentage of incoming data that is considered for analytics. Higher the percentage greater would be the accuracy. Considering these two issues, the proposed work is intended to find a better solution by gaining insight on real-time streaming data with minimum response time and greater accuracy. This paper combines the two technology giants TensorFlow and Apache Kafka. is used to handle the real-time streaming data since TensorFlow supports analytics support with deep learning algorithms. The Training and Testing is done on Uber connected vehicle public data set RideAustin. The experimental result of RideAustin shows the predicted failure under each type of vehicle parameter. The comparative analysis showed 16% improvement over the traditional Machine Learning algorithm.


2014 ◽  
Vol 150 (4) ◽  
pp. 331-352 ◽  
Author(s):  
Ronald Indergand ◽  
Stefan Leist
Keyword(s):  
Data Set ◽  

2020 ◽  
Author(s):  
Matthias Maeyens ◽  
Brianna Pagán ◽  
Piet Seuntjens ◽  
Bino Maiheu ◽  
Nele Desmet ◽  
...  

<p>In recent years, extend periods of drought have been affecting the water quality and availability in  the Flanders region in Belgium. Especially the coastal region experienced an increased salinization of ground and surface water. The Flemish government therefore decided to invest in a dense IoT water quality monitoring network aiming to deploy 2500 water quality sensors  primarily in surface water but also in ground water and sewers. The goal of this "Internet of Water" project is to establish an operational state of the art monitoring and prediction system in support of future water policy in Flanders. </p><p>Since Flanders is a relatively small region (13,522 km²), placing this many sensors will result in one of the most dense surface water quality sensor networks in the world. Each sensor will continuously measure several indicators of water quality and transmit the data wirelessly. This allows us to continuously monitor the water quality and build a big enough data set to be able to use a more data driven approach to predicting changes  in water quality. However, as with any sensor system, the quality of the data can vary in time due to problems with the sensors, incorrect calibration or unforeseen issues. Real-time data quality control is crucial to prevent unsound decisions due to faulty data.</p><p>This contribution will give a general overview of the network and it’s specifications, but mainly focus on the implementation of the data stream as well as methods that are implemented to guarantee good data quality. More specifically the architecture and setup of a real-time data quality control system is described. Which will add quality control flags to measurements.  This system is  integrated with the NGSI API introduced by FIWARE, which forces us to make specific design decisions to acommodate to the NGSI API.</p>


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