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Article Citation - WoS: 44Citation - Scopus: 49A Neural Network-Based Approach for Calculating Dissolved Oxygen Profiles in Reservoirs(Springer London Ltd, 2003) Soyupak, S; Karaer, F; Gürbüz, H; Kivrak, E; Sentürk, E; Yazici, AA Neural Network (NN) modelling approach has been shown to be successful in calculating pseudo steady state time and space dependent Dissolved Oxygen (DO) concentrations in three separate reservoirs with different characteristics using limited number of input variables. The Levenberg-Marquardt algorithm was adopted during training. Pre-processing before training and post processing after simulation steps were the treatments applied to raw data and predictions respectively. Generalisation was improved and over-fitting problems were eliminated: Early stopping method was applied for improving generalisation. The correlation coefficients between neural network estimates and field measurements were as high as 0.98 for two of the reservoirs with experiments that involve double layer neural network structure with 30 neurons within each hidden layer. A simple one layer neural network structure with 11 neurons has yielded comparable and satisfactorily high correlation coefficients for complete data set, and training, validation and test sets of the third reservoir.Article On the Definition of Sequential Consistency(Elsevier Science Bv, 2005) Sezgin, A; Gopalakrishnan, GThe definition of sequential consistency is compared with an intuitive notion of correctness. That the definition is not strong enough is illustrated through a hypothetical memory system which is clearly incorrect, yet sequentially consistent. It is claimed that the reason for this is the absence of a relation between what actually happens (temporal order) and what seems to happen (logical order). A stronger version of sequential consistency is proposed. (c) 2005 Elsevier B.V. All rights reserved.Conference Object Citation - Scopus: 3A simulation model for mine production sequences(2006) Aydiner,K.; Çelebi,N.; Paşamehmetoǧlu,A.G.Mine design process strictly dependent on the economical variables of the orebody and the rock mass properties having effect on the physical parameters of the intended mining system. In addition, the dynamic aspects of the possible system must be taken into account. Difficulty in design arises mainly from the difficulty in obtaining enough and reliable data. Collecting enough and quality data requires to costly and timely procedures. Therefore, the mine design engineers have to consider alternative cases in their designs or they have to design with limited data. This study presents a simulation model that can be used to develop the production subsystem model of an underground mining system. A mechanized production system model and a decision analysis tool using a discrete event simulation process were developed. The tool allows an engineer with experimenting his/her design to generate a model that can meet the targeted production rate.Article Citation - WoS: 6Citation - Scopus: 5Synthesis of a regular polymer containing pseudo-polyether cages(Elsevier Science Sa, 2005) Cihaner, A; Önal, AMA new compound consisting of 2-thienyl units linked by polyether bridge has been synthesized and its electrochemical polymerization was performed via constant potential electrolysis (CPE) in an electrolytic solution containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6)) dissolved in CH3CN. Chemical polymerization was carried out using FeCl3 as oxidizing agent. It is found that both methods gave the same polymer product without any cleavage of the polyether bridge between thiophene (Th) rings. Although as synthesized polymers exhibited no conductivity, they gain conductivity via chemical doping using 12 vapor exposure. The polymers were characterized using FTIR spectroscopic technique and 12 doping was monitored using in-situ electron spin resonance (ESR) spectroscopy. Thermal behavior of electrochemically prepared polymer was investigated using differential scanning calorimetry, DSC and thermogravimetric analysis, TGA. (c) 2005 Elsevier B.V. All rights reserved.Conference Object Citation - Scopus: 3Design of Frp Retrofitted Flexural Members Against Debonding Failures(2006) Gunes,O.; Karaca,E.; Gunes,B.Use of fiber reinforced polymer (FRP) composites in seismic retrofitting of structural members has been steadily increasing in recent years. An important design issue with significant performance and safety implications is the debonding of externally bonded FRP reinforcement in flexural members. This paper provides the highlights of an experimental and analytical research aimed at understanding and modeling of debonding failures in FRP strengthened reinforced concrete beams. An evolutionary experimental program investigated debonding failure mechanisms and modes in beams strengthened in shear and/or flexure in various configurations and tested under monotonic and cyclic loading. A newly developed fracture mechanics based model considers the global energy balance of the system and predicts the debonding failure load by characterizing the dominant mechanisms of energy dissipation during debonding. Validation of the model is performed using experimental data obtained from several independent experimental studies.Article Citation - Scopus: 13Carrier Transport Properties of Ins Single Crystals(2002) Qasrawi,A.F.; Gasanly,N.M.The electrical resistivity and Hall effect of indium sulfide single crystals are measured in the temperature range from 25 to 350 K. The donor energy levels located at 500, 40 and 10 meV below the conduction band are identified from both measurements. The data analysis of the temperature-dependent Hall effect measurements revealed a carrier effective mass of 0.95 m0, a carrier compensation ratio of 0.9 and an acoustic deformation potential of 6 eV. The Hall mobility data are analyzed assuming the carrier scattering by acoustic and polar optical phonons, and ionized impurities.Article Citation - WoS: 12Citation - Scopus: 15Discrete Parameter-Nonlinear Constrained Optimisation of a Gear Train Using Genetic Algorithms(inderscience Enterprises Ltd, 2005) Dolen, M.; Kaplan, H.; Seireg, A.This paper investigates the optimal design of a four-stage gear train using genetic algorithms. Five different genetic encoding schemes, which incorporate various heuristic search techniques, are proposed to deal with the most critical constraints of the problem. The fitness criterion used by all genetic algorithms includes a merit function for minimising the size of the gearbox. The results show improvement in the design merit over previous approaches without reliance on the designer's interaction to avoid geometric constraint violations and facilitate the convergence.Conference Object Citation - Scopus: 1Ore-Age: an Intelligent Assisting and Tutoring System for Mining Method Selection(2003) Guray,C.; Celebi,N.; Atalay,V.; Gunhan,A.In the past studies about the mining method selection process, which is among the most critical aspects in the mining engineering discipline, there are attempts to build up a systematic approach to make this selection. But, these approaches work based on static databases and fail in inserting the intuitive feelings and engineering judgments of experienced engineers to the selection process. In this study, a hybrid system based on 13 different expert systems and one interface agent is developed, to make mining method selection for the given ore-bodies. The learning procedure to insert the expertise of the experienced engineers to the selection process, works based on a neuro-fuzzy model, combining the TSK model of the fuzzy theory and a two layered neural network with the utilization of the back-propagation algorithm. Again, to supply the maximum assistance to the users, the agent executes the system's tutoring procedure in case an inexperienced user enters the system, to complete his/her missing knowledge about mining method selection. The system that is being developed in this study can be introduced as the first example of dynamic, intelligent assisting and tutoring systems in the mining profession.Article Citation - WoS: 1Citation - Scopus: 1Spectroelectrochemical Investigation of the Anodic Oxidation of Dibenzo-18(Elsevier Science Sa, 2004) Cihaner, A; Önal, AMPoly(dibenzo-18-crown-6) (poly-DB18C6) was synthesized by electrochemical oxidation of dibenzo-18-crown-6 (DB18C6) using a mixture of acetonitrile and dichloromethane as the solvent and tetrabutylammonium tetrafluoroborate (TBABF(4)) or tetrabutylammonium hexafluorophosphate (TBAPF(6)) as supporting electrolyte. The anodic polymerization of DB18C6 was investigated using in situ ESR and in situ UV-Vis spectroscopic techniques. Spectroelectrochemical (SPEL), properties and thermal analysis of the resulting polymers have been investigated using UV-Vis spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). (C) 2004 Elsevier B.V. All rights reserved.Article Citation - Scopus: 1Yielding of Functionally Graded Long Tubes Under Thermal Loading;(2006) Akiş,T.The elastic behavior of a functionally graded non-uniform heat generating long tube is investigated analytically. The thermal conductivity and the modulus of elasticity of the tube material are assumed to vary radially in nonlinear forms. Making use of Tresca's yield criterion, the effect of grading parameters on the yielding behavior of the tube is investigated. It is observed that plastic flow may commence at the inner surface, at the outer surface or inside the tube depending on the functionally grading parameters.
