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Öğe Adaptive position controller for a PM DC linear motor(2000) Demirci, RecepBu makale de sabit mıknatıslı DC lineer motor için adapte edilebilen pozisyon kontrolör tasarımı sunulmuştur. DC lineer motor da üretilen kuvvet, hareket eden kısmın fonsiyonu olarak değiştiğinden motor doğrusal olmayan pozisyon-kuvvet karakteristiğine sahiptir. Hareket eden ksımın konumunu kontrol etmek için. PI, PID gibi sabit parametreli kontrolör kullanıldığıda, tasarlanan kontrol sisteminin komutları takip etme performansları yeterli olmamaktadır. Dolayısıyla bu çalışmada model refaranslı adapte edilebilen pozisyon kontrolör tasarlanmış ve pratik olarak da gerçekleştirilerek söz konusu lineer motorun doğrusal olmayan parametrelerin kontrol sistemi üzerindeki etkileri azaltılmıştır.Öğe Batı Karadeniz bölgesindeki dalga enerjisi potansiyelinin araştırılması(2006) Uygur, İlyas; Demirci, Recep; Saruhan, Hamit; Özkan, Arif; Belenli, İbrahimÇevreye zarar vermeyen doğal, temiz ve sürekli yenilenebilir enerji türlerinin başlıcaları, rüzgar, güneş, biyolojik, su ve dalga enerjisidir. Dalga enerjisi, ilk yatırım ve bakım giderlerinden başka masrafı olmayan, girdi bedeli gerektirmeyen, doğaya her hangi bir kirletici bırakmayan, ucuz, temiz, çevreci ve büyük potansiyele sahip bir enerji kaynağıdır. Üç tarafı denizlerle çevrili Türkiye için de dalga enerjisi, enerji sıkıntısı çektiğimiz şu günlerde ve ileriki yıllarda bir çözüm olabilecek durumdadır. Bu bağlamda Batı Karadeniz (Akçakoca) bölgesinde beş yıllık gözlemsel çalışmalar yapılmış ve bölgenin dalga enerji potansiyeli hesaplanmıştır. Meteoroloji verilerinin incelenmesi neticesinde bölgedeki dalga enerjisi güç potansiyeli, mevcut teknolojik sistemler için yetersiz olarak gözükmektedir. Gelişen teknolojiyle birlikte üretilen yeni enerji dönüştürücülerinin de gelişeceği gözünde bulundurularak, yetersiz olarak tespit edilen dalga enerjisi potansiyeli daha verimli bir şekilde değerlendirilebilir. Bu çalışma bundan sonraki araştırmalar için bir temel teşkil edebilecektir.Öğe AN INVESTIGATION OF WAVE ENERGY POTENTIAL IN WESTERN BLACK SEA REGION(Pamukkale Univ, 2006) Uygur, Ilyas; Demirci, Recep; Saruhan, Hamit; Ozkan, Arif; Belenli, IbrahimThe main energy sources which are natural, clean, environmentally friendly, and renewable are wind power, solar energy, biomass energy, hydro energy, and wave energy. The wave energy has no cost except for the first investment and maintenance. There is also no cost for input energy. Besides these, it has no pollution effect on the environment, it is cheap and there is a huge potential all around the world. Wave energy is a good opportunity to solve the energy problem for Turkey which is surrounded by seas. Concerning all these facts, it has been conducted some studies which included five years of observation in the Western Black Sea Region (Akcakoca). The wave energy potential has also been calculated. From this sutdy results, it can be concluded that the wave energy potential of this region is inefficient. It is believed that by the improvement of the new energy converter devices in future, this low potential can be used more efficiently and as a result this study might be used as a basis for the future researches.Öğe Measurement of epidermal thickness in a patient with psoriasis by computer-supported image analysis(Assoc Bras Divulg Cientifica, 2004) Alper, Murat; Kavak, Ayşe; Parlak, Ali Haydar; Demirci, Recep; Belenli, İbrahim; Yeşildal, NurayThe aim of the present study was to measure full epidermal thickness, stratum corneum thickness, rete length, dermal papilla widening and suprapapillary epidermal thickness in psoriasis patients using a light microscope and computer-supported image analysis. The data obtained were analyzed in terms of patient age, type of psoriasis, total body surface area involvement, scalp and nail involvement, duration of psoriasis, and family history of the disease. The study was conducted on 64 patients and 57 controls whose skin biopsies were examined by light microscopy. The acquired microscopic images were transferred to a computer and measurements were made using image analysis. The skin biopsies, taken from different body areas, were examined for different parameters such as epidermal, corneal and suprapapillary epidermal thickness. The most prominent increase in thickness was detected in the palmar region. Corneal thickness was more pronounced in patients with scalp involvement than in patients without scalp involvement (t = -2.651, P = 0.008). The most prominent increase in rete length was observed in the knees (median: 491 mum, t = 10. 117, P = 0.000). The difference in rete length between patients with a positive and a negative family history was significant (t = -3.334, P = 0.03), being 27% greater in psoriasis patients without a family history. The differences in dermal papilla distances among patients were very small. We conclude that microscope-supported thickness measurements provide objective results.Öğe Renkli görüntülerin bağıntı matrisine dayalı ayrıştırılması(2007) Demirci, Recep; Katırcıoğlu, FerzanIn this study, segmentation is done by using the similarity feature between neighbour pixells. Image segmentation was not done on the original image, it was done on the similarity image by using region growing algoritm. Distance and similarity measure functions and relation matrix are explained on similarity image. It was tried to answer the effect of similarity measure functions and how threshold and normality value effect the segmentation.Öğe Rule-based automatic segmentation of color images(Elsevier Gmbh, 2006) Demirci, RecepA rule-based segmentation algorithm for color images has been presented in this paper. The proposed strategy is similar to region growing algorithm where the seed points are automatically selected and grown. The similarity percents of neighboring pixels are calculated by means of fuzzy reasoning rules, and the merging of the pixels with regions is performed by comparing the similarity percent with the similarity threshold value. The algorithm does not require any prior knowledge of the number of regions existing in the image and decreases the computational load required for the fuzzy c-means (FCM). Several computer simulations have been performed and the results have been discussed. The simulation results indicate that the proposed algorithm yields segmented color image of perfect accuracy.Öğe Similarity relation matrix-based color edge detection(Elsevier Gmbh, Urban & Fischer Verlag, 2007) Demirci, RecepA novel edge detection algorithm for color images was described in this paper. In the proposed method, smoothness of each pixel in color image is firstly calculated by means of similarity relation matrix and is normalized to maximum gray level. In other words, color image in three-dimensional color spaces is mapped into one dimension. Accordingly the edges are performed in such a way that pixels lower than thresholds are assigned to be edge. Thus with proposed method, edge pixels in a color image are detected simultaneously without any complex calculations such as gradient, Laplace and statistical calculations. (c) 2006 Elsevier GrnbH. All rights reserved.
