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Yayın Identification of sensor location and link flow reconstruction using turn ratio and flow sensors in an arterial network(Taylor and Francis Ltd., 2024) Taşcıkaraoğlu, Fatma Yıldız; Aksoy, GökerIn this article, a quadratic programming problem is considered to identify all link flows in an arterial network when there are unmeasured link flows. A graphical method is provided to determine the minimum number of measurements and sensor locations required to obtain a fully observable model. It is shown that this method is also valid for the augmented graph with turn ratio measurements. If the minimum measurements required are met, a fully determined network can be obtained. If there is not enough measurement, a bound on the magnitude of the resulting inaccuracy in terms of vehicle kilometers traveled (VKT) can be calculated by the proposed linear programming method. The model is that of a queueing network; the parameters describe network geometry, saturation flow rates, turning ratios, timing plan and link flows. Three case studies are conducted to validate this approach. The first two cases are to calculate all missing flows by using a few numbers of measurements and minimum number of measurements required, respectively. Upper and lower bounds in terms of VKT are also calculated for these cases. Third case is to obtain a fully determined network with the minimum number of flow measurements when turn ratio sensors are included. Real measurements are collected from a network in Mugla including 55 links and 16 intersections. Vissim simulator is used to analyze the accuracy of the link flow calculations obtained from the proposed method. The results show that the proposed programming method can calculate the missing flows with a high accuracy and short computation time.Yayın Analyzing the freeway capacity and examining the improvements via connected and autonomous vehicles(Işık Üniversitesi, 2022-09-05) Küçükoğlu, Berkcan; Aksoy, Göker; Işık Üniversitesi, Lisansüstü Eğitim Enstitüsü, İnşaat Mühendisliği Yüksek Lisans ProgramıTechnology is getting better and improving each and every day. Transportation systems are getting smarter and more tolerant of human errors. In the near future, it won't be surprising to see autonomous vehicles on our roads. However, this can not happen in one night and there will be a transition phase where conventional and automated vehicles will coexist. Connected vehicle technology will provide many opportunities. Reduced accident rates, reduced emissions, reduced parking requirements, reduced congestion and reliable journeying times are some of these advantages. Micro simulations have been broadly adopted for many evaluations, and there are serious challenges that should be answered. In this regard, simulation model calibration and validation are crucial for evaluating the potential improvements offered by connected car technology. In this research, possible changes happening on the freeway merge sites through the usage of connected vehicle technology tried to be investigated by using a VISSIM simulation model that meets current peak capacities. As a result of the experiments and investigations, it has been found that, when compared to traffic with only conventional vehicles, the vehicle capacity in the research area increases by an average of 5% for every 10% increase in autonomous vehicles. Additionally, it was shown that penetration rates up to 40% had the best results, outperforming all other percentages by a considerable margin. To conclude, the addition of autonomous vehicles for the enhancement of effective traffic management made a significant improvement to the transportation study. However, additional studies and applications of the same logics with various models is advised to improve future studies.
