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Conference Object Citation - WoS: 17Citation - Scopus: 23Maintenance, Sustainability and Extendibility in Virtual and Remote Laboratories(Elsevier Science Bv, 2011) Kara, Ali; Ozbek, Mehmet Efe; Cagiltay, Nergiz Ercil; Aydin, ElifThis study presents discussions on sustainability of Virtual and Remote Laboratories (VRL), and provides challenges toward maintenance of VRLs. Technical and pedagogical issues in extension and sustenance of VRLs are discussed with the experiences of the authors gained in the development of a VRL system, European Remote Radio Laboratory (ERRL) platform. Moreover, the study presents actions to be taken in sustenance plan and expendability of VRL system with the advances in Information and Communication Technologies (ICT) and educational technologies along with the needs of educators and learners in formal education. (C) 2011 Published by Elsevier Ltd.Editorial Dual-Coil Relay Driver Uses Only Two Mosfets(Reed Business information Us, 2009) Ozbek, Mehmet Efe[No Abstract Available]Editorial Piezoelectric driver finds buzzers resonant frequency(Canon Communications inc, 2008) Ozbek, Mehmet Efe[No Abstract Available]Editorial Citation - WoS: 1Microcontroller Drives Piezoelectric Buzzer at High Voltage(Canon Communications inc, 2012) Ozbek, Mehmet Efe[No Abstract Available]Editorial Microcontroller Drives Piezoelectric Buzzer at High Voltage Through One Pin(Canon Communications inc, 2012) Ozbek, Mehmet Efe[No Abstract Available]Article Citation - WoS: 7Citation - Scopus: 8Robust and Adaptive Control Design of a Drilling Rig During the Operating Modes(Sage Publications Ltd, 2019) Sadeghi, Amir Nobahar; Arikan, Kutluk Bilge; Ozbek, Mehmet Efe; Baranoglu, Besim; Nobahar Sadeghi, AmirOil well drilling towers have different operating modes during a real operation, like drilling, tripping, and reaming. Each mode involves certain external disturbances and uncertainties. In this study, using the nonlinear model for the modes of the operation, robust and/or adaptive control systems are designed based on the models. These control strategies include five types of controllers: cascaded proportional-integral-derivative, active disturbance rejection controller, loop shaping, feedback error learning, and sliding mode controller. The study presents the design process of these controllers and evaluates the performances of the proposed control systems to track the reference signal and reject the uncertain forces including the parametric uncertainties and the external disturbances. This comparison is based on the mathematical performance measures and energy consumption. In addition, three architectures are presented to control the weight on bit during drilling process, and also to maintain a preset constant weight on bit, two control approaches are designed and presented.Article Citation - WoS: 25Citation - Scopus: 34Modelling and Controlling of Drill String Stick Slip Vibrations in an Oil Well Drilling Rig(Elsevier, 2022) Sadeghi, Amir Noabahar; Arikan, Kutluk Bilge; Ozbek, Mehmet Efe; Noabahar Sadeghi, AmirMitigating of drill string vibrations, plays a distinctive role in increase of rate of penetration and consequently decrease of the operation costs, prevent of severe damages to drill string and bit, increase of drilling operation quality and safety, and enhance the performances of the controllers. This study deals with modelling and controlling of drill string vibrations with focus on stick slip vibrations in vertical wells. The approach taken to subdivide the drill string into smaller torsional sections and model the complete system dynamically and employ the extracted torsional model to model the stick slip vibrations mathematically. To mitigate and or active control of stick slip vibrations, three architectures are developed and proposed, manipulation of the rotational speed, manipulation of the weight on bit, and increasing of the damping in the bottom of the drill string. The performance of each strategy is analysed individually as well as relative to each other, using a mathematical measure when the drill string length is divided into smaller torsional sections. By the aid of the simulations and mathematical measures, it is shown that manipulation of rotational speeds at the surface may not be an effective solution to reduce the stick slip vibrations, however manipulation of weight on bit and increasing of damping at the bottom of string can be two effective solutions to mitigate these kinds of vibrations. As a general conclusion, it is proved that the manipulation of bottom side drilling parameters is more effective than the manipulation of surface drilling parameters.Article Citation - WoS: 1Citation - Scopus: 1Design of a System Solution That Modernizes Legacy Supervisory Control and Data Acquisition Systems as an Early Detection System(Sage Publications Ltd, 2018) Demir, Besir; Tumay, Ahmet; Ozbek, Mehmet Efe; Cavus, EnverBackground: In industrial disasters, early detection of problems and crisis management are critical for saving the lives of people and reducing the impact of disasters. Purpose: In this study, we design a special gateway system that bridges the gap between different communication protocols and enables legacy supervisory control and data acquisition systems to function early detection systems for potential industrial disasters. Methods: The system uses a new queue mechanism to substantially improve the problem of data loss found in conventional supervisory control and data acquisition systems and utilizes identification (ID) prioritization to enable early detection of problems. The proposed system is implemented and tested on a Linux-based, 3G-capable Modbus gateway system. Modbus is used as the communication protocol and 3G technology is utilized to provide high-speed wireless data transfer components. The Modbus gateway device uses an ARM-based EP9302 processor and has digital input/output, relay outputs, and RS485 outputs. Conclusion: This study is significant as it is the first work to show the application of the priority query execution method for Modbus gateway devices.Conference Object Citation - Scopus: 7Lms and Interactivity - Technical Issues for Remote Laboratories(IEEE, 2007) Kolberg,S.; Courivaud,D.; Özbek,M.E.; Ozbek, Mehmet EfeWeb Services has proven to be a stable and effective way of integrating resources on cross-platform systems. Web Services provides developers with interfaces that are well structured and accessible to most web programming languages. For interactive applications in LMS systems, things get more complicated. Mashups, which are composite applications, raises issues related to browser security models and static learning content. Some of these issues and possible solutions will be discussed in this paper.Article Citation - WoS: 7Citation - Scopus: 7Torsional Model of the Drill String, and Real-Time Prediction of the Bit Rotational Speed and the Torque on Bit, in an Oil Well Drilling Tower(Elsevier, 2020) Sadeghi, Amir Noabahar; Arikan, Kutluk Bilge; Ozbek, Mehmet EfeIn an oil well drilling tower, the Bottom Hole Assembly (BHA) data is needed to optimize the controllable variables such as weight on bit and bit rotational speed for obtaining the optimum drilling rate. In order to acquire the data of the BHA, a simple and low-cost method, can be predicting of these parameters. In this study, first the torsional modelling of the drill string is implemented by dividing its length to some equal sections, then the effects of dividing on the estimation accuracy are evaluated. Using an ADRC (Active Disturbance Rejection Controller) in the vertical and rotational motions dynamics, some proper observers to predict the bit rotational speed, rock stiffness and torque on bit, in real-time are designed and presented. Dividing the drill string length to more sections, leads to design high order observer, so the performance of the designed observers with different orders, are compared and analysed. Employing the integral square error analysis, it is revealed, dividing the drill string length to more sections, leads more accurate in the prediction of bit rotational speed, but not more effect on the estimated rock stiffness, and torque on bit. Also it is shown that increasing of the observer bandwidth, leads to more accurate in the estimation, but concludes the estimation be more sensitive to the sensor noise. Employing the presented observers in this study to estimate the BHA data, in addition to enhance the drill quality and safety, the controllable variables are optimized, and consequently the whole drilling process can be robustly controlled, with no needs to the expensive measurement systems at the BHA.
