Determining damages in ceramic plates by using discrete wavelet packet transform and support vector machine

In this study, an analysis was conducted by using discrete wavelet packet transform (DWPT) and support vector machine (SVM) methods to determine undamaged and cracked plates. The pendulum was used to land equal impacts on plates in this experimental study. Sounds, which emerge from plates as a result of the impacts applied to undamaged and cracked plates, are sound signals used in the analysis and DWPT of these sound signals were obtained with 128 decompositions for feature extraction. The first four components, reflecting the characteristics of undamaged and cracked plates within these 128 components, were selected for enhancing the performance of the classifier and energy values were used as feature vectors. In the study, the SVM model was created by selecting appropriate C and γ parameters for the classifier. Undamaged and cracked plates were seen to be successfully identified by an analysis of the training and testing phases. Undamaged and cracked statuses of the plates that are undamaged and have the analysis had identified different cracks. The biggest advantage of this analysis method used is that it is high-precision, is relatively low in cost regarding experimental equipment and requires hardware

Investigation of Liquid Level Sensors and an Application: Water Level Measurement

Günlük yaşamda farklı alanlarda durağan veya hareketli durumlarda sıvı seviyesinin ölçümünün doğru bir şekilde gerçekleştirilmesi gerekmektedir. Sıvının türüne, hassasiyete ve maliyete göre temaslı/temassız sensörler kullanılabilir. Bu çalışmada sıvı seviye ölçümünde kullanılan ultrasonik sensör, kapasitif sensör, diferansiyel basınç transdüseri, kızılötesi sensör ve dikey hareketli şamandıranın çalışma prensipleri incelenmiştir. Örnek bir uygulama olarak silindire yakın bir şekle sahip bir kaptaki su seviyesinin ölçüm işlemi sensörler ile gerçekleştirilmiştir. Kaptaki farklı seviyelerde gerçekleştirilen ölçümlerde gerçek su seviyesine yakın değerler sensörlerden okunmuştur. Sensör seçiminde temaslı /temassız, sürekli/ayrık zamanlı veri alma gibi durumlar göz önünde bulundurulur. Sensörün çalıştığı ortamın sıcaklığı gibi parametrelerin göz ardı edilmesi ölçüm hatasının artmasına neden olmaktadır. Sensörlerin kalibrasyonunun doğru yapılması ölçme hatalarının azalmasını sağlayacaktır.The measurement of liquid level in stable or moving conditions must be performed correctly at different areas of daily life. In according to liquid type, sensitivity and cost, contact/contactless sensors may be used. In this study, the working principles of ultrasonic sensor, capacitive sensor, differential pressure transducer, infrared sensor and vertical moving float which are used in liquid level measurement were examined. Measurement of water level in a container which is similar to cylindrical shape was carried out by sensors as a sample application. Values which are closed to the actual water level were read by sensors as a result of measurement in different levels of the container. Factors such as contact/contactless, receiving data continuously/discrete-time are taken into account in the selection of sensor. Ignoring parameters such as the environment temperature at which sensors work, causes to increase in measurement error. Accurate calibration of the sensors will provide to reduce the measurement errors

HARMONIC ANALYSIS OF SVPWM INVERTER USING MULTIPLE-PULSES METHOD

Space Vector Modulation (SVM) technique is a popular and an important PWM technique for three phases voltage source inverter in the control of Induction Motor. In this study harmonic analysis of Space Vector PWM (SVPWM) is investigated using multiple-pulses method. Multiple-Pulses method calculates the Fourier coefficients of individual positive and negative pulses of the output PWM waveform and adds them together using the principle of superposition to calculate the Fourier coefficients of the all PWM output signal. Harmonic magnitudes can be calculated directly by this method without linearization, using look-up tables or Bessel functions. In this study, the results obtained in the application of SVPWM for values of variable parameters are compared with the results obtained with the multiple-pulses method

SVPWM İNVERTERİN ÇOKLU DARBELER YÖNTEMİYLE HARMONİK ANALİZİ

Uzay Vektör Modülasyon (SVM) tekniği asenkron motor kontrolünde üç fazlı gerilim beslemeli inverter için popüler ve önemli bir PWM tekniğidir. Bu çalışmada Uzay Vektör PWM (SVPWM) inverterin çoklu darbeler yöntemini kullanarak yapılan harmonik analizi incelenmiştir. Çoklu darbeler yöntemi çıkış PWM dalga şeklinin her bir pozitif ve negatif darbesinin Fourier katsayılarını hesaplamakta ve tüm PWM çıkış sinyalinin Fourier katsayılarını hesaplamak için süperpozisyon ilkesini kullanarak birbirleriyle toplamaktadır. Harmonik genlikleri; doğrusallaştırma, tarama tabloları kullanımı ya da Bessel fonksiyonları olmaksızın bu yöntemle doğrudan hesaplanabilir. Bu çalışmada, değişken parametre değerleri için SVPWM uygulamasından elde edilen sonuçlar, çoklu darbeler yöntemiyle elde edilen sonuçlarla karşılaştırılmıştır

The application of instantaneous reactive power calculation methods to a real power system

Many calculation methods have been developed to calculate the reactive power used in energy transmission lines. In this study; preferred instantaneous power calculation techniques such as instantaneous orthogonal currents, phase shifting, Peng theory and p-q power theory have been examined, these methods have been applied to the Isiklar load 2 connected to the Yatagan and Kemerkoy thermal plants via a 380 kV energy transmission line and the results have been analyzed. When the simulation results obtained from the analysis are examined; it has been determined that even though the instantaneous reactive power calculation methods used for energy transmission lines with three phase, balanced, periodical voltage and current have some differences, the instantaneous reactive power values obtained are quite close. In the study, it has been observed that the numerical calculations made by using methods to calculate the reactive power applied to a real transmission system are in accordance with simulation results.Scientific Research Projects Coordinating Office of Marmara UniversityMarmara University [FEN-C-DRP-161111-0300]This study was supported by the Scientific Research Projects Coordinating Office of Marmara University (Project No. FEN-C-DRP-161111-0300).WOS:0003045129000342-s2.0-8486255721