Cenk Ozan

An Ant Colony Optimization Algorithm for Area Traffic Control

The optimization of traffic signal control is at the heart of urban traffic control. Traffic signal control which encloses delay, queuing, pollution, fuel consumption is a multi-objective opti‐ mization. For a signal-controlled road network, using the optimization techniques in deter‐ mining signal timings has been discussed greatly for decades. Due to complexity of the Area Traffic Control (ATC) problem, new methods and approaches are needed to improve effi‐ ciency of signal control in a signalized road network. In urban networks, traffic signals are used to control vehicle movements so as to reduce congestion, improve safety, and enable specific strategies such as minimizing delays, improving environmental pollution, etc. [1]. Signal systems that control road junctions are operated according to the type of junction. Al‐ though the optimization of signal timings for an isolated junction is relatively easy, the opti‐ mization of signal timings in coordinated road networks requires further research due to the “offset” term. Early methods such as that of [2] only considered an isolated signalized junc‐ tion. Later, fixed time strategies were developed that optimizing a group of signalized junc‐ tions using historical flow data [3]. For the ATC, TRANSYT-7F is one of the most useful network study software tools for optimizing signal timing and also the most widely used program of its type. It consists of two main parts: A traffic flow model and a signal timing optimizer. Traffic model utilizes a platoon dispersion algorithm that simulates the normal dispersion of platoons as they travel downstream. It simulates traffic in a network of signal‐ ized intersections to produce a cyclic flow profile of arrivals at each intersection that is used to compute a Performance Index (PI) for a given signal timing and staging plan. The PI in TRANSYT-7F may be defined in a number of ways. One of the TRANSYT-7F’s PI is the Dis‐ utility Index (DI). The DI is a measure of disadvantageous operation; that is stops, delay, fuel consumption, etc. Optimization in TRANSYT-7F consists of a series of trial simulation

Determining On-Street Parking Places in Urban Road Networks Using Meta-Heuristic Harmony Search Algorithm

This study aims to develop a simulation/optimization model for the solution to the problem of determining on-street parking places in urban road networks. The problem is dealt within the Discrete Network Design (DND) context due to the binary decision variables and the bi-level programming technique is used for the solution of the problem. The upper level represents the determination of on-street parking places while the reaction of drivers’ to the design is handled in user equilibrium manner in the lower level. The upper level problem is formulized as a non-linear mixed integer programming problem and the meta-heuristic Harmony Search (HS) optimization technique is employed for the solution. In the proposed model, VISUM traffic analysis software is utilized as the simulation tool for solving the lower level problem. The performance of the proposed model is tested on Sioux-Falls road network which has widely been used on DND studies in the previous works. Results show that determining optimal or near-optimal on-street parking places may be achieved by using the proposed model.

Modelling Domestic Air Transport Demand and Evaluating under Scenarios

Ulkemizde ulasim alt turler arasindaki dengesizlik ve entegrasyon en onemli problem olarak karsimiza cikmaktadir. Calismada son yillarda ichat hava tasimaciligi alt turunde gozlenen talebin aylik degisimini yansitabilen indeksleme yontemi kullanilarak modellemesi yapilmis, gelecege yonelik tahminler yapilarak alt turlerdeki dengesizligin giderilmesi yonunde onerilerde bulunulmustur. Modelleme calismasinda bagimsiz degiskenler olarak Satin alma Gucu Paritesi ve jet yakit fiyatlari kullanilmistir. Kullanilan yontem ile aylik ve mevsimsel degismelere duyarli bir model gelistirilmistir. Yapilan hesaplamalar sonucunda gelir seviyesinde iyimser gelismeler gozlenmesi ve jet yakit fiyatlarinda dusuk seyrin gozlenmesi durumunda karayolu ulasim sisteminin ardindan hava tasimaciliginin demiryolu sistemi ile ciddi bir rekabet icinde olacagi belirlenmistir. Bu nedenle ucret politikalarinda gerekirse jet yakit fiyatlarinda vergi duzenlemesi ile talep gelisiminin desteklenmesinin gerekli oldugu dusunulmektedir. The lack of balance and integration between transportation modes in Turkey is one of the main problems. In this study, domestic air transport demand is modeled and evaluated under scenarios. For this purpose, indexing method which is able to indicate observed monthly and seasonal variations in demand is used. Proposals are suggested in order to overcome the lack of balance between transportation modes. In modeling, purchasing power parity and jet fuel prices as independent variables are used. Results showed that the developed model using indexing method is substantially sensitive to observed monthly and seasonal variations in domestic air transport demand. Furthermore, in the event that there are optimistic an increase in the income level and a crawl in the jet fuel prices, domestic air transport can rival with railways for second place in the transportation modes behind highways. For this reason, it is considered regulation on wages policy and tax of jet fuel prices necessary to support development of domestic air transport demand. Anahtar kelimeler: Havayolu, Ulasim talebi, Indeksleme yontemi.