https://hdl.handle.net/20.500.12809/8876 2026-04-06T11:15:21Z https://hdl.handle.net/20.500.12809/9096 Probabilistic seismic hazard assessment of Muğla, Turkey İnce, Gökçe Çiçek; Yılmazoğlu, Mehmet Uğur Muğla Province, which has been selected as the study area, is located in the Aegean Extension Region (AER), where seismic motions are widely observed. Moreover, the AER is the most active part of the Eastern Mediterranean Region in terms of seismic activity, and this seismicity has been continuing increasingly. This study aims to determine the seismic hazard of Muğla Province and its surroundings by using the probabilistic seismic hazard method. The earthquake dataset including 19,824 seismic records that were used in the research was obtained from the national and international earthquake catalogs. The data about the active fault zones in the study area were acquired from the General Directorate of Mineral Research and Exploration. The seismic source zones were generated as homogeneous areas as possible taking into account the active fault zones. The earthquakes in seismic source zones were eliminated based on the time and distance frames. The annual recurrence relationships of the source zones were determined using the least-squares method taking into account the earthquakes with a magnitude of 5 or above. The peak acceleration values on the bedrock were calculated using the attenuation relationships of the selected local and global ground motion prediction models. The calculations were performed using the SEISRISK III software package utilizing the homogeneous Poisson Process Model according to the exceedance probability of 10% for 50 years (corresponding to the return period of 475 years). The peak acceleration values on bedrock were found to range between 0.11 and 0.42. The study revealed that the Gökova fault zone (Zone 4) was the most active source in terms of the seismic hazard in the region and that the seismic hazard of the southwestern part of the region was greater compared to other parts. 2021-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/4531 Utilization of waste marble dust as an additive in cement production Aruntaş, Hüseyin Yılmaz; Guru, Metin; Dayı, Mustafa; Tekin, İlker In this experimental study, the usability of waste marble dust (WMD) as an additive material in blended cement has been investigated. For this purpose, waste marble dust added cements (WMDCs) have been obtained by intergrinding WMD with Portland cement clinker at different blend ratios: 2.5%, 5.0%, 7.5% and 10% by weight. 40 x 40 x 160 mm mortar prisms have been produced with the obtained cements. Strength tests have been carried out on mortar specimen at 7, 28, and 90 days. WMDCs have been compared to each other as well as to control cements of CEM I and CEM II with respect to their physical, chemical and mechanical properties. Obtained results showed that WMDCs conform to EN 197-1 standard and thus 10% WMD can be used as an additive material in cement manufacturing. (C) 2010 Elsevier Ltd. All rights reserved. WOS: 000279118300062 2010-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/1586 Optimization of service frequencies in bus networks with harmony search algorithm: An application on Mandl's test network Ceylan, Hüseyin; Özcan, Tayfun In developing countries, efforts to increase the efficiency of bus transportation, which is the most common type of urban public transport systems, have been increasing in recent years. Many studies addressing the performance of bus systems focus on approaches to optimizing user and operator benefits. In this study, a bi-level simulation/ optimization model is developed to optimize service frequencies in urban bus networks. At the upper level, a meta-heuristic Harmony Search (HS) optimization technique based model is proposed for solving an objective function that represents operator and user costs. At the lower level, the transit assignment problem, which represents the distribution of demand over the transit network, is solved. In the proposed model, a time-table based transit assignment approach is used for the exact calculation of transfer wait times, and the transit assignment problem is solved using VISUM software based on a logit-based choice model. The developed model has been applied to a test network that is widely used in transit network design studies. The results show that the HS based model can be used effectively to solve the service frequency optimization problem. 0000-0002-6646-1497; WOS: 000453336100019 2018-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/1577 Optimization of Headways and Departure Times in Urban Bus Networks: A Case Study of Corlu, Turkey Ceylan, Hüseyin; Özcan, Tayfun The traffic congestion, which has become one of the major problems of developed and developing countries, has led to a shift in the way public transport systems are viewed, and it has accelerated efforts to increase the efficiency of these systems. In recent studies, several approaches, in which both user and operator benefits are evaluated together in order to increase the demand for public transportation systems and to ensure the sustainability of these systems, are emphasized. In this study, a bilevel simulation/optimization model is developed to optimize service headways and departure times of first buses from the beginning of the routes in urban bus networks. At the upper level of the proposed model, a multiobjective function representing user and operator costs is evaluated using the metaheuristic harmony search (HS) optimization technique. The transit assignment problem, which represents the distribution of transit users over the routes, is handled at the lower level. In the proposed model, the transit assignment problem is solved by the timetable-based assignment approach with VISUM transport planning software. The timetable-based transit assignment is an approach in which the perception errors within the users' route choice are taken into consideration and the transfer wait times can be precisely calculated. The proposed model is applied to a real-life urban bus network of the Corlu district (Tekirda, Turkey), and the effectiveness of the model on a medium-sized urban bus system has been demonstrated. The results show that the user and operator benefits can be simultaneously increased by adding an initial departure offset parameter to the problem. WOS: 000455605500001 2018-01-01T00:00:00Z