Yazar "Gok, Mehmet" seçeneğine göre listele

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    Design of a Real-Time USB Interfaced Multi-Channel Power System Harmonics Detection System
    (Ieee, 2015) Gok, Mehmet; Gorgunoglu, Salih; Sefa, Ibrahim
    In recent years, the increase of non-linear loads caused more harmonics on power systems. With the advent of the loads that are sensitive to power quality, harmonics are more important than in the past. Determination of those harmonics is required for the avoidance of problems. In this paper, a practical low cost harmonics detection system is designed and performance of the system is considered on single and multi-channel usage. 400th harmonic can be detected under 3.5 mu s over 8- channels using the developed device and processing software. Results show that proposed system can be used for a broad range of harmonics detection systems in real-time.
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    Examination of Speed Contribution of Parallelization for Several Fingerprint Pre-Processing Algorithms
    (Univ Suceava, Fac Electrical Eng, 2014) Gorgunoglu, Salih; Orak, Ilhami Muharrem; Cavusoglu, Abdullah; Gok, Mehmet
    In analysis of minutiae based fingerprint systems, fingerprints needs to be pre-processed. The pre-processing is carried out to enhance the quality of the fingerprint and to obtain more accurate minutiae points. Reducing the pre-processing time is important for identification and verification in real time systems and especially for databases holding large fingerprints information. Parallel processing and parallel CPU computing can be considered as distribution of processes over multi core processor. This is done by using parallel programming techniques. Reducing the execution time is the main objective in parallel processing. In this study, pre-processing of minutiae based fingerprint system is implemented by parallel processing on multi core computers using OpenMP and on graphics processor using CUDA to improve execution time. The execution times and speedup ratios are compared with the one that of single core processor. The results show that by using parallel processing, execution time is substantially improved. The improvement ratios obtained for different pre-processing algorithms allowed us to make suggestions on the more suitable approaches for parallelization.
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    Research and Implementation of a USB Interfaced Real-Time Power Quality Disturbance Classification System
    (Univ Suceava, Fac Electrical Eng, 2017) Gok, Mehmet; Sefa, Ibrahim
    In this study, the research and implementation of an automatic power quality (PQ) recognition system are presented. This system contains a USB interfaced multichannel data acquisition (DAQ) device and a graphical user interfaced (GUI) application. The DAQ device consists of an analog-to-digital (ADC) converter, field programmable gate array (FPGA) and a USB first in first out (FIFO) buffer interface chip. The application employs Stockwell Transform (ST) technique combined with neural network model to build the classifier. Eight basic and two combined PQ disturbances are determined for the classification. Different from the previous studies, the synthetic signals used for neural network training are modified by adding the harmonics detected in the real signal. This approach is used to increase the classifier accuracy against the real line power signal. Also, ST is simplified by using only the frequencies which are required in the feature extraction step to reduce the processing time. Developed application handles the signal processing, the classification, and the database recording tasks by using multi-threaded programming approach under the mean time of 41 ms. The experimental results show that the proposed power quality disturbance detection system is capable of recognizing and reporting power quality faults effectively within the real-time requirements.