Mekatronik Mühendisliği Bölümü

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Citation Count: Alsaka, Dina Yaqoob; Arpali, Çağlar; Arpali, Serap A. (2018). "A comparison of iterative Fourier transform algorithms for image quality estimation", Optical Review, Vol.25, No.5, pp.625-637.
A comparison of iterative Fourier transform algorithms for image quality estimation
(2018) Alsaka, Dina Yaqoob; Arpali, Çağlar; Arpali, Serap Altay; 20809
A comparison was established between two iterative Fourier transform algorithms (IFTAs), such as the original Gerchberg–Saxton (GS) and the mixed-region amplitude freedom (MRAF) algorithms, for the hologram reconstruction of different target images through the full reference image quality estimation (IQE) and pixel homogeneity in the Fourier plane presented theoretically and experimentally. The comparison was applied depending upon both algorithms based on a computer-generated hologram (CGH) implemented utilizing a reflective phase-modulated liquid-crystal spatial light modulator (LC-SLM) to obtain the digital kinoform holograms of the desired intensity distributions. These digital holograms were applied to reconstruct the intensity patterns for 852 nm, which represents a laser beam source. The theoretical and experimental results of the reconstructed patterns obtained using the MRAF algorithm were found to be smoother and better than the patterns obtained using the GS algorithm. Unmodulated light beam (dc term) is removed from the reconstructed patterns attributed to digital kinoform holograms of MRAF algorithm as an alternative to the theoretical and experimental results without using any additional optic equipment at the light path. Moreover, this paper discussed the full reference objective quality estimations, such as mean square error (MSE), peak signal-to-noise ratio (PSNR), structural content (SC), normalized absolute error (NAE), normalized cross correlation (NK), and homogeneity of pixels, through the contrast (Cont) and inverse difference moment (IDM) for numerical and experimental results. According to the two desired intensity distributions processed theoretically and experimentally, the results of MRAF algorithm were found to be in the highly accurate recovered phase, the quality of image was enhanced, and the dc term was decreased. Image quality estimation of full reference objective relay on the feedback algorithms experimental attestation has not been implemented yet.
Citation Count: Alsaka, Dina Yaqoob; Arpali, Caglar; Arpali, Serap Altay, "A comparison of iterative Fourier transform algorithms for image quality estimation", Optical Review, Vol. 25, No. 5, pp. 625-637, (2018)
A Comparison of Iterative Fourier Transform Algorithms for Image Quality Estimation
(Optical Soc Japan, 2018) Alsaka, Dina Yaqoob; Arpalı, Çağlar; Altay Arpalı, Serap; 20809
A comparison was established between two iterative Fourier transform algorithms (IFTAs), such as the original Gerchberg-Saxton (GS) and the mixed-region amplitude freedom (MRAF) algorithms, for the hologram reconstruction of different target images through the full reference image quality estimation (IQE) and pixel homogeneity in the Fourier plane presented theoretically and experimentally. The comparison was applied depending upon both algorithms based on a computer-generated hologram (CGH) implemented utilizing a reflective phase-modulated liquid-crystal spatial light modulator (LC-SLM) to obtain the digital kinoform holograms of the desired intensity distributions. These digital holograms were applied to reconstruct the intensity patterns for 852 nm, which represents a laser beam source. The theoretical and experimental results of the reconstructed patterns obtained using the MRAF algorithm were found to be smoother and better than the patterns obtained using the GS algorithm. Unmodulated light beam (dc term) is removed from the reconstructed patterns attributed to digital kinoform holograms of MRAF algorithm as an alternative to the theoretical and experimental results without using any additional optic equipment at the light path. Moreover, this paper discussed the full reference objective quality estimations, such as mean square error (MSE), peak signal-to-noise ratio (PSNR), structural content (SC), normalized absolute error (NAE), normalized cross correlation (NK), and homogeneity of pixels, through the contrast (Cont) and inverse difference moment (IDM) for numerical and experimental results. According to the two desired intensity distributions processed theoretically and experimentally, the results of MRAF algorithm were found to be in the highly accurate recovered phase, the quality of image was enhanced, and the dc term was decreased. Image quality estimation of full reference objective relay on the feedback algorithms experimental attestation has not been implemented yet.
Citation Count: Afsin, Mehmet Ertug; Schmidt, Klaus Werner; Schmidt, Ece Guran, "A configurable CAN FD controller: architecture and implementation", 2017 25th Signal Processing And Communications Applications Conference (SIU), (2017).
A configurable CAN FD controller: architecture and implementation
(IEEE, 2017) Afşin, Mehmet Ertuğ; Schmidt, Klaus Werner; Schmidt, Ece Güran
CAN FD is a new standard which provides fast. data rate while preserving the compatibility with CAN (controller area network). In this paper, a Configurable IP core architecture (A-CAN) which is compatible with the CAN FD standard, is proposed. Different than existing CAN/CAN FD controllers, the numbers and sizes of transmit and receive buffers of A-CAN can be configured in run time. To this end, A-CAN enables the best use of single controller hardware for different applications and enables improving the real time communication performance. A CAN communicates with the host device over SPI without any specific interface requirements. A-CAN is implemented on an FPGA Evaluation Board and its functionally is verified at a rate of 2 Mbps.
Citation Count: Schmidt, K.W., Breindl, C. (2014). A framework for state attraction of discrete event systems under partial observation. Information Sciences, 281, 265-280. http://dx.doi.org/10.1016/j.ins.2014.05.026
A framework for state attraction of discrete event systems under partial observation
(Elsevier Science Inc., 2014) Schmidt, Klaus Werner; Breindl, Christian; 17337
State attraction for discrete event systems (DES) addresses the problem of reaching a desired subset of the plant state space after a bounded number of event occurrences. The problem of state attraction arises for example in fault-tolerant supervisory control or in the control of reconfigurable manufacturing systems, and is also applicable to systems biological problems such as the control of gene regulatory networks. State attraction is investigated with the assumption of full event observation in the existing literature. This paper extends the concept of state attraction to the case of partial observation. The notion of weak attraction under partial observation (WAPO) is introduced and necessary and sufficient conditions for the existence of a supervisor under partial observation that achieves WAPO are derived. Furthermore, a solution algorithm is proposed that finds such supervisor whenever it exists. It is shown that such supervisor can always be realized as a subautomaton of the observer automaton of the DES plant. An application example from systems biology illustrates the obtained results.
Citation Count: Schmidt, Klaus Werner; Schmidt, E.G, "A Longest-Path Problem for Evaluating the Worst-Case Packet Delay of Switched Ethernet", 2010 International Symposium On Industrial Embedded Systems, Sies 2010 - Conference Proceedings, pp. 205-208, (2010).
A Longest-Path Problem for Evaluating the Worst-Case Packet Delay of Switched Ethernet
(2010) Schmidt, Klaus Werner; Schmidt, E. G.; 17337
In the recent years, the use of real-time Ethernet protocols becomes more and more relevant for time-critical networked industrial applications. In this context, this paper presents a method to compute the worst-case packet delays on switched Ethernet. Based on an evaluation of the packet delays at each switch port and the network topology, we construct a weighted directed graph that allows to find the worst-case end-toend packet delay by solving a conventional longest-path problem
Citation Count: Leblebicioglu, M. Kemal; Zengin, Yasin; Schmidt, Klaus Werner, "A new multi-agent decision making structure and application to model-based fault diagnosis problem", 2017 25th Signal Processing And Communications Applications Conference (SIU), (2017).
A new multi-agent decision making structure and application to model-based fault diagnosis problem
(IEEE, 2017) Leblebicioğlu, Kemal; Zengin, Yasin; Schmidt, Klaus Werner
A new hierarchical multi-agent decision-making structure has been proposed. There are two phases of the structure. The first phase is the construction phase where the decision making structure consisting of switching and classification agents is built on the training data set generated by the system scenarios. In construction phase, switching and classification agents are trained and made ready for decision making. In the decision phase, which is the second phase, the class of the new data sample is decided. This process is carried out by the transmission of the data sample to the correct classifier agent by the switching agents and the classification by the classifier agent. The proposed structure is applied to a complex fault identification problem and a successful result is obtained. The structure is also adaptable to other big data decision making problems.
Citation Count: Ulaş, Beldek; Leblebicioğlu, Kemal (2015). "A new systematic and exible method for developing hierarchical decision-making models", Turkish Journal of Electrical Engineering and Computer Sciences, Vol. 23, No. 1, pp. 279-297.
A new systematic and exible method for developing hierarchical decision-making models
(2015) Ulaş, Beldek; Leblebicioğlu, Kemal; 59950
The common practice in multilevel decision-making (DM) systems is to achieve the final decision by going through afinite number of DM levels. In this study, a new multilevel DM model is proposed. This model is called the hierarchical DM (HDM) model and it is supposed to provide a exible way of interaction and information ow between the consecutive levels that allows policy changes in DM procedures if necessary. In the model, in the early levels, there are primary agents that perform DM tasks. As the levels increase, the information associated with these agents is combined through suitable processes and agents with higher complexity are formed to carry out the DM tasks more elegantly. The HDM model is applied to the case study 'Fault degree classification in a 4-tank water circulation system'. For this case study, the processes that connect the lower levels to the higher levels are agent development processes where a special decision fusion technique is its integral part. This decision fusion technique combines the previous level's decisions and their performance indicator suitably to contribute to the improvement of new agents in higher levels. Additionally, the proposed agent development process provides exibility both in the training and validation phases, and less computational effort is required in the training phase compared to a single-agent development simulation carried out for the same DM task under similar circumstances. Hence, the HDM model puts forward an enhanced performance compared to a single agent with a more sophisticated structure. Finally, model validation and eficiency in the presence of noise are also simulated. The adaptability of the agent development process due to the exible structure of the model also accounts for improved performance, as seen in the results.
Citation Count: Beldek, U., Leblebicioğlu, M.K. (2015). A new systematic and flexible method for developing hierarchical decision-making models. Turkish Journal Of Electrical Engineering And Computer Sciences, 23(1), 279-297. http://dx.doi.org/10.3906/elk-1302-3
A new systematic and flexible method for developing hierarchical decision-making models
(TUBİTAK Scientific&Technical Research Council Turkey, 2015) Beldek, Ulaş; Leblebicioğlu, Mehmet Kemal; 59955
The common practice in multilevel decision-making (DM) systems is to achieve the final decision by going through a finite number of DM levels. In this study, a new multilevel DM model is proposed. This model is called the hierarchical DM (HDM) model and it is supposed to provide a flexible way of interaction and information flow between the consecutive levels that allows policy changes in DM procedures if necessary. In the model, in the early levels, there are primary agents that perform DM tasks. As the levels increase, the information associated with these agents is combined through suitable processes and agents with higher complexity are formed to carry out the DM tasks more elegantly. The HDM model is applied to the case study 'Fault degree classification in a 4-tank water circulation system'. For this case study, the processes that connect the lower levels to the higher levels are agent development processes where a special decision fusion technique is its integral part. This decision fusion technique combines the previous level's decisions and their performance indicator suitably to contribute to the improvement of new agents in higher levels. Additionally, the proposed agent development process provides flexibility both in the training and validation phases, and less computational effort is required in the training phase compared to a single-agent development simulation carried out for the same DM task under similar circumstances. Hence, the HDM model puts forward an enhanced performance compared to a single agent with a more sophisticated structure. Finally, model validation and efficiency in the presence of noise are also simulated. The adaptability of the agent development process due to the flexible structure of the model also accounts for improved performance, as seen in the results.
Citation Count: Yalçın, F., Öztürk, A., Gülgeç, M. (2016). A parametric study on the elastic-plastic deformation of a centrally heated two-layered composite cylinder with free ends. Archives Of Mechanics, 68(3), 203-228.
A parametric study on the elastic-plastic deformation of a centrally heated two-layered composite cylinder with free ends
(Polish Acad Science Inst. Fundamental Technological Research, 2016) Yalçın, F.; Öztürk, A.; Gülgeç, Müfit; 4168
In this paper, an elastic-plastic deformation of a centrally heated two-layered composite cylinder with free ends subjected to uniformly distributed internal energy generation within an inner cylinder is studied using Tresca's yield condition and its associated flow rule. Stress, strain and displacement distributions in the composite cylinder made of elastic-perfectly plastic material are derived considering the influence of geometric parameters as well as material properties such as yield strength, modulus of elasticity, Poisson's ratio, coefficient of thermal conduction and coefficient of thermal expansion. Yielding starts at the outer boundary or at the axis corresponding to an 'edge regime' of Tresca's prism in both cases. Propagations of the plastic regions are studied due to an increase of a heat generation
Citation Count: Khalid, H.M.; Kirik, M.S.; Schmidt, K.W., "Abstraction-Based Supervisory Control for Recon-Gurable Manufacturing Systems?", Ifac Proceedings Volumes (Ifac-Papersonline), Vol. 4, No. 1, pp. 157-162, (2013).
Abstraction-Based Supervisory Control for Recon-Gurable Manufacturing Systems?
(2013) Khalid, Harith M.; Kırık, Mustafa Sancay; Schmidt, Klaus Werner; 271229
Reconfiguration control for discrete event systems (DES) is concerned with the realization of different system configurations by modification of the supervisory control loop. In this paper, we study the reconfiguration supervisor design for reconfigurable manufacturing systems (RMS) that comprise multiple components. We construct a modular supervisor for each configuration and system component in order to realize each active configuration and to quickly change between configurations. Different from the existing literature that is focused on monolithic design, our method is abstraction-based, and, hence applicable to large-scale DES.
Citation Count: Turkyilmaz, S...et al. (2011). "An Electromagnetic Micro-Power Generator for Low Frequency Vibrations with Tunable Resonance", Eurosensors XXV, Vol. 25.
An Electromagnetic Micro-Power Generator for Low Frequency Vibrations With Tunable Resonance
(Elsevier Science BV, 2011) Türkyılmaz, S.; Zorlu, O.; Muhtaroğlu, A.; Kulah, Haluk
This paper presents an electromagnetic (EM) micro-power generator with tunable resonance frequency which can harvest energy from low frequency environmental vibrations. The reported power generator up-converts low frequency environmental vibrations before mechanical-to-electrical energy conversion by utilizing two diaphragms with different resonance frequencies. Power is generated through electromagnetic induction by a magnet attached to the low frequency diaphragm, and a 50 turn, 2.1 Omega coil, and a magnetic piece on the high frequency diaphragm. Both of the diaphragms are fixed to a common frame via rubber springs, which makes the resonance frequency of each diaphragm tunable. The fabricated prototype generates 5.2 mV and 3.21 mu W RMS power by up-converting 13 Hz, 7.5 mm peak-to-peak vibrations to 200 Hz. Tunability of the resonance frequency is experimentally verified by operating the same device at 2-30 Hz external vibrations. (C) 2011 Published by Elsevier Ltd.
Citation Count: Evci, C., Gülgeç, M. (2012). An experimental investigation on the impact response of composite materials. International Journal of Impact Engineering, 43, 40-51.
An experimental investigation on the impact response of composite materials
(Pergamon-Elsevier Science Ltd, 2012) Evci, Celal; Gülgeç, Müfit; 243247; 4168
Due to the improved impact performance characteristics, composites are widely used in engineering and military applications to absorb the impact energy. Determination of impact response of composite materials provides the engineer and the manufacturer with critical knowledge to understand the failure criteria, initiation of the first failure and damage growth through the laminates. This study covers the investigation of impact damage growth and determination of Hertzian failure and maximum force thresholds in three different types of composites. Unidirectional E-Glass, woven E-Glass and woven Aramid composite samples with dimensions of 100 x 100 mm are subjected to low velocity impact with an instrumented impact test system. Rebound, on-set of perforation and perforation limits of composites are found out. Also, energy profile diagrams of both unidirectional and plain weave E-Glass composites are obtained. According to test results, woven composites are found to be superior to unidirectional composites in the protection limit of low velocity impact. It is also observed that damage growth in woven composites is restricted within a smaller area. Impact tests conclude that strength of the composite materials under dynamic loading increases considerably compared to static loading case as a result of strain rate sensitivity.
Citation Count: Schmidt, K...et al. (20109. "An Experimental Study of the Flexray Dynamic Segment",Ifac Proceedings Volumes (Ifac-Papersonline), Vol. 43, No. 7, pp. 413-418.
An Experimental Study of the Flexray Dynamic Segment
(IFAC Secretariat, 2010) Schmidt, Klaus Werner; Schmidt, Ece G.; Demirci, Ali; Yürüklü, Emrah; Karakaya, Utku
It is expected that the time-triggered FlexRay bus will replace the event-triggered Controller Area Network (CAN) for the high-speed in-vehicle communication in future automobiles. To this end, FlexRay provides a static segment for the transmission of periodic messages and a dynamic segment that is suitable for exchanging event-based (sporadic) messages. In this paper, we experimentally evaluate the operation of the FlexRay dynamic segment. In particular, we study how the maximum and average message delays are affected if the length of the dynamic segment, the message payload, the utilization of the dynamic segment and the priority assignment changes. Our experiments are carried out on a FlexRay network with 6 nodes.
Citation Count: Öncü, H., Schmidt, K.W. (2013). An integrated scheduling and control model for multi-mode projects. Flexible Services And Manufacturing Journal, 25(1-2), 230-254. http://dx.doi.org/10.1007/s10696-012-9138-3
An integrated scheduling and control model for multi-mode projects
(Springer, 2013) Hazır, Öncü; Schmidt, Klaus Werner; 4168
In today's highly competitive uncertain project environments, it is of crucial importance to develop analytical models and algorithms to schedule and control project activities so that the deviations from the project objectives are minimized. This paper addresses the integrated scheduling and control in multi-mode project environments. We propose an optimization model that models the dynamic behavior of projects and integrates optimal control into a practically relevant project scheduling problem. From the scheduling perspective, we address the discrete time/cost trade-off problem, whereas an optimal control formulation is used to capture the effect of project control. Moreover, we develop a solution algorithm for two particular instances of the optimal project control. This algorithm combines a tabu search strategy and nonlinear programming. It is applied to a large scale test bed and its efficiency is tested by means of computational experiments. To the best of our knowledge, this research is the first application of optimal control theory to multi-mode project networks. The models and algorithms developed in this research are targeted as a support tool for project managers in both scheduling and deciding on the timing and quantity of control activities
Citation Count: Hazir, Ö.; Schmidt, K.W.; Eryilmaz, U.,"An Optimization Model to Coordinate Scheduling and Controling in Projects: Case With İnstantaneous Control Constraints", Opt-I 2014 - 1St International Conference On Engineering and Applied Sciences Optimization, Proceedings, pp. 2095-2110, (2014).
An Optimization Model to Coordinate Scheduling and Controling in Projects: Case With İnstantaneous Control Constraints
(National Technical University of Athens, 2014) Hazır, Öncü; Schmidt, Klaus Werner; Eryılmaz, Utkan; 17337
Today, many enterprises in different industries take part in various projects, and organizational performances depend more and more on project performances. In order to maximize performance, effective management of project functions is crucial. In this regard, we focus on scheduling and control functions and their relation. Characteristics of data sharing among them and possible integration strategies are theoretically investigated. A model base for a decision support framework that accounts for these interdependencies and supports managers is developed. To solve the formulated integrated project scheduling and control problem, a tabu search algorithm is combined with optimal control techniques. As a result, a project schedule as well as the means and timing of interventions are determined such that the project cost is minimized. The obtained results are supported by computational experiments. Integrated models and algorithms to be developed aim to fill an important theoretical gap in project management.
Citation Count: Ozturk, Ali; Gulgec, Mufit, "Analytical Solution of Thermal Stresses in a Functionally Graded Solid Cylinder within Parabolic Continuous Grading", Mechatronics and Computational Mechanics, Vol. 307, pp. 364-, (2012)
Analytical Solution of Thermal Stresses In A Functionally Graded Solid Cylinder Within Parabolic Continuous Grading
(Trans Tech Publications LTD, 2012) Öztürk, Ali; Gülgeç, Müfit; 4168
This paper presents analytical solutions of the thermal stresses in a functionally graded solid cylinder with fixed ends in elastic region. These thermal stresses are due to the uniform heat generation inside the cylinder. Material properties of the functionally graded (FG) cylinder vary radially according to a parabolic form. The material properties are assumed to be independent of the temperature which are yield strength, elasticity modulus, thermal conduction coefficient, thermal expansion coefficient and Poisson's ratio. The solutions for the thermal stresses are valid for both homogeneous and functionally graded materials.
Citation Count: Moor, T.; Schmidt, K.; Perk, S.,"Applied Supervisory Control for A Flexible Manufacturing System",Ifac Proceedings Volumes (Ifac-Papersonline), Vol. 10, No. 1, (2010).
Applied Supervisory Control for A Flexible Manufacturing System
(2010) Moor, Thomas; Schmidt, Klaus Werner; Perk, Sebastian
This paper presents a case study in the design and implementation of a discrete event system (DES) of real-world complexity. Our DES plant is a flexible manufacturing system (FMS) laboratory model that consists of 29 interacting components and is controlled via 107 digital signals. Regarding controller design, we apply a hierarchical and decentralised synthesis method from earlier work in order to achieve nonblocking and safe closed-loop behaviour. Regarding implementation, we discuss how digital signals translate to discrete events from a practical point of view, including timing issues. The paper demonstrates how both, design and implementation, are supported by the open-source software tool libFAUDES.
Citation Count: Kamacıoğlu, C., Baykal, Y., Yazgan, E. (2013). Averaging of receiver aperture for flat-topped incidence. Optics and Laser Technology, 52, 91-95. http://dx.doi.org/10.1016/j.optlastec.2013.04.011
Averaging of receiver aperture for flat-topped incidence
(Elsevier Science Ltd, 2013) Kamacıoğlu, Canan; Baykal, Yahya; Yazgan, Erdem; 7812
Using a flat-topped profile for the incident beam, the power scintillation index for weak atmospheric turbulence is formulated and analytically evaluated. Through the use of the aperture averaging factor, the averaging effect of the finite receiver aperture on the intensity fluctuations for a flat-topped incident beam is examined. The influence of the order of flatness on the averaging is investigated. At large propagation lengths, increasing the flatness parameter decreases the power scintillations and it is possible to further reduce the scintillation by increasing the receiver aperture. Increasing the structure constant increases this effect
Citation Count: Özbilge, Kubilay; Ergezer, Halit. "Çekilebilir Sahte Hedef Etkinliğinin Modelleme Ve Simülasyon İle Analizi", 8. Ulusal Savunma Uygulamaları Modelleme ve Simülasyon Konferansı, Ankara 19-20 Kasım 2019, pp. 152-161.
Çekilebilir Sahte Hedef Etkinliğinin Modelleme Ve Simülasyon İle Analizi
(2019) Özbilge, Kubilay; Ergezer, Halit; 293396; 293396
Sahte hedefler, uçağın savaş alanında hayatta kalmasını artırmak için radar güdümlü füzeden korumak için kullanılan bir savunma yöntemlerindendir. Bu çalışmada savaş uçaklarında kullanılan çekilebilir aktif sahte hedeflerin uçağın hayatta kalabilirliğine etkisi, uçağın çekilebilir sahte hedef kullandığı ve kullanmadığı durumlar için vurulma olasılıkları ve füzenin kaçırma uzaklığı değerleri hesaplanarak analiz edilmiştir. Çalışmamızda açık kaynaktan elde edilen veriler kullanılmıştır. Jenerik yapıda kurgulanan savaş uçağı modeli, çekilebilir sahte hedef modeli ve radar modeli ile elde edilen veriler sunulmuştur. Benzetim sonuçları çekilebilir aktif sahte hedef kullanımının savaş uçaklarına özellikle angajmanın son safhasında koruma sağladığını ortaya koymaktadır.
Classification of fMRI Data by Using Clustering
(IEEE, 2015) Moğultay, Hazal; Alkan, Sarper; Yarman Vural, Fatoş T.
Recognition of the the cognitive states by using functional Magnetic Rezonans Imaging (fMRI) data is a challenging problem that has been a focus of scientific research for a long time. In this study the effectiveness of clustering and the ensemble learning techniques on fMRI dataset is investigated and different paramaters are compared. Moreover, the performance of these techniques are tested on both raw voxel intensity values and meshes formed by multiple voxels. Clusters are compared to the functional brain regions, however higher performances are obtained when the number of clusters is higher than the number of functional brain regions.

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