4 results
Search Results
Now showing 1 - 4 of 4
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, BesimOil 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: 76Citation - Scopus: 109Effect of Social Media Sharing on Destination Brand Awareness and Destination Quality(Sage Publications Ltd, 2020) Dedeoglu, Bekir Bora; van Niekerk, Mathilda; Kucukergin, Kemal Gurkan; De Martino, Marcella; Okumus, FevziThis study examines the effect of social media sharing on tourism destination brand awareness and destination natural and service quality and also examines the moderating roles of country of origin (COI; macro and micro) image on destination natural and service quality. Data were collected from 568 domestic and international tourists who have visited Alanya, Turkey. Relationships in the study were examined through structural equation modeling. As one of the components of social media sharing, participant sharing positively affects destination brand awareness, whereas any significant effect of nonparticipant sharing on destination brand awareness was not found. Destination brand awareness positively influences tourist perceptions of both destination service quality and destination natural quality. COI image moderates most of the relationships.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.Article Citation - WoS: 43Citation - Scopus: 44Reliability Assessment of System Under a Generalized Cumulative Shock Model(Sage Publications Ltd, 2020) Gong, Min; Eryilmaz, Serkan; Xie, MinReliability assessment of system suffering from random shocks is attracting a great deal of attention in recent years. Excluding internal factors such as aging and wear-out, external shocks which lead to sudden changes in the system operation environment are also important causes of system failure. Therefore, efficiently modeling the reliability of such system is an important applied problem. A variety of shock models are developed to model the inter-arrival time between shocks and magnitude of shocks. In a cumulative shock model, the system fails when the cumulative magnitude of damage caused by shocks exceed a threshold. Nevertheless, in the existing literatures, only the magnitude is taken into consideration, while the source of shocks is usually neglected. Using the same distribution to model the magnitude of shocks from different sources is too critical in real practice. To this end, considering a system subject to random shocks from various sources with different probabilities, we develop a generalized cumulative shock model in this article. We use phase-type distribution to model the variables, which is highly versatile to be used for modeling quantitative features of random phenomenon. We will discuss the reliability characteristics of such system in some detail and give some clear expressions under the one-dimensional case. Numerical example for illustration is also provided along with a summary.
