Browsing by Author "Eliiyi, Ugur"

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Citation - WoS: 14
Citation - Scopus: 19
Deadhead Trip Minimization in City Bus Transportation: a Real Life Application
(Svenciliste U Zagrebu, Fakultet Prometnih Znanosti, 2013) Nasibov, Efendi; Eliiyi, Ugur; Ertac, Mefharet Ozkilcik; Kuvvetli, Umit
The quality of public transportation services is one of the most important performance indicators of modern urban policies for both planning and implementation aspects. Therefore, along with the size of the city, the significance of appropriate cost evaluation and optimization of all related transportation activities increases as well. One of the most important cost factors for the public transport agencies is naturally the fuel consumption of the vehicles. In this study, the attention is focused on the metropolitan bus transport service. The specific aim is to minimize a significant portion of total fuel utilization that occurs due to the so called deadhead trip or dead mileage, which is defined as the idle distance covered by the vehicle between the garage and the route terminal stops without carrying any passengers. In this study, the results of four mathematical models for minimizing the total deadhead trip distance covered in city bus services of Izmir are presented. The models vary due to the inclusion of garage capacity restrictions or operator distinction for supporting both operational and strategical decisions. All models are applied to the recent bus schedule data, which consist of 293 routes, 1,424 buses and 10 garages, for obtaining the optimal route bus-garage allocations and garage capacities. The results of the Decentralized-Capacitated model, which is appropriate for quick implementation, promise a 7.8% reduction in total dead mileage. While on the other hand, if all garage capacities can be expanded and the bus service is maintained only by one operator as modelled in the Centralized-Uncapacitated case, even a 31.4% improvement is possible in the long term. The environmental gains as well as the financial benefits to be achieved when the solutions are actually implemented, justify the practical contribution of the study.
Citation - WoS: 17
Citation - Scopus: 18
Economic and Environmental Viability Analysis for a Photovoltaic-Powered Led System in Tunnel Illumination
(Sila Science, 2011) Eliiyi Türsel, Deniz; Caylan, Tayfun; Eliiyi, Ugur
In this study, we conduct an economical and environmental viability analysis for a photovoltaic-powered tunnel illumination system in Aydin, Turkey. Recently, the rapid depletion of fossil fuels and global warming concerns render the renewable energy resources as major solutions for the global energy problem. Our study focuses on solar energy and its application to tunnel illumination. One of the longest tunnels in Turkey is considered for the analysis, and three alternative systems are proposed for replacing the current system in the tunnel that uses the grid power. A detailed cost and feasibility analysis is performed for the alternatives, taking into account the time value of money in an inflationary economy. Net present worth, payback period and internal rate of return calculations are used for analytical purposes. The environmental viability is assessed via the computation of resulting reduction in CO2 emissions by the proposed systems. Results indicate that the proposed systems are more advantageous than the existing one.