Catheters are used in medical applications such as bronchoscopy, colonoscopy, angiography. Due to the catheters are in direct contact with the tissue in these procedures, their movements must be controlled. In this study, three different sliding-mode controllers that can be used to control the movement of the catheter have been proposed. These are the classical sliding mode controller, quasi sliding mode controller, and asymptotic sliding mode controller structures. Performance comparison of the controllers was made by assessing the closed-loop system response. The results indicated that the performance of the quasi sliding mode controller was better than the other controllers. It has been proposed to use a fuzzy logic-based highest controller to improve the performance of the quasi sliding mode controller. The proposed controller structure updates the controller parameters depending on the predicted disturbance magnitude and position error. The results show that the real-time performance of the quasi sliding mode controller is improved by the change of the proposed control structure.

No abstract

ÖzSon 10 yılda biyopsi ve tanı işlemleri esnasında doktor vasıtasıyla manuel ve robotik olarak gerçekleştirilen endoskopi, kolonoskopi, bronkoskopi gibi işlemlerde oluşabilecek komplikasyonları en aza indirmeye yarayacak sistemlerin üzerine çalışılmaya başlanmıştır. Bu sistemlerin en önemli özelliği yönlendirilecek kateterin manyetik özelliğe sahip olması ve elektromanyetik sistemler ile kateterin temassız bir şekilde yönlendirilmesidir. Bunun yanı sıra tedaviye yönelik başka işlemler için de manyetik özelliğe sahip kapsül, robot, ilaç taşıma sistemleri vb. araçlar geliştirilmektedir. Bu araçların yönlendirilmesi de bahsedilen sistemler aracılığıyla temassız bir şekilde gerçekleştirilebilmektedir. Bu çalışmada temassız yönlendirmeyi sağlayan manyetik kateter navigasyon sistemleri hakkında bilgi verilmektedir.

Objective: This study aimed to develop an algorithm to distinguish the patients with bisphosphonate-related osteonecrosis of the jaws (BRONJ) from healthy controls using cone beam computerized tomography (CBCT) images by evaluating both trabecular and cortical bone changes through the whole body of the mandibular bone. Methods: Patient dataset was created from axial CBCT images of 7 BRONJ patients (28 slices) and eight healthy controls (27 slices). The healthy bone of healthy controls, bone sclerosis of BRONJ patients, bone necrosis of BRONJ patients, and normal appearing bone of BRONJ patients (NBP) were labelled on CBCT images by three maxillofacial radiologists. Proposed algorithm had preparation and background cancellation, mandibular bone segmentation and centerline determination, spatial transformation of gray values, and classification steps. Results: Significant differences between the statistical moments (mean, variance, skewness, kurtosis, standard error, median, mode and coefficient of variance) of healthy and diseased (bone sclerosis and necrosis) groups were observed (p = 0.000, p < 0.05). Also, variations were noted between healthy controls and NBP of BRONJ patients (p = 0.000, p < 0.05). The statistical moments were utilized to develop the algorithm which has resulted with accuracy of 0.999, sensitivity of 0.998, specificity of 0.998, precision of 1, recall of 0.998, AUC of 1, and F1 score of 0.999 in identification of BRONJ patients from healthy ones. Conclusion: The proposed algorithm differentiated the mandibular bones of the healthy and the BRONJ patients with high accuracy in the present test sample.

Bu makaleye şu şekilde atıfta bulunabilirsiniz(To cite to this article): Şener M., Arslan F.M., Gürses B.O. ve Gürlek G., "Experimental investigation of thermoelectric self-cooling system for the cooling of ultrasonic transducer drivers", Politeknik Dergisi, *(*): *, (*).