9 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 9 / 9
Yayın Soft decision trees(IEEE, 2012) İrsoy, Ozan; Yıldız, Olcay Taner; Alpaydın, Ahmet İbrahim EthemWe discuss a novel decision tree architecture with soft decisions at the internal nodes where we choose both children with probabilities given by a sigmoid gating function. Our algorithm is incremental where new nodes are added when needed and parameters are learned using gradient-descent. We visualize the soft tree fit on a toy data set and then compare it with the canonical, hard decision tree over ten regression and classification data sets. Our proposed model has significantly higher accuracy using fewer nodes.Yayın Çok-hipotezli süperpikseller ile sahne bölütleme ve etiketleme(IEEE, 2015-06-19) Ak, Kenan Emir; Ateş, Hasan FehmiSüperpikseller son zamanlarda imge bölütleme ve sınıflandırma problemlerinde giderek önem kazanmaktadır. Sahne etiketlemede imge öncelikle bir süperpiksel algoritması ile görsel olarak tutarlı küçük parçalara bölütlenmekte; daha sonra süperpikseller farklı sınıflara ayrı¸stırılmaktadır. Sınıflandırma performansı kullanılan süperpiksel algoritmasının özellikleri ve parametre ayarlarından önemli ölçüde etkilenmektedir. Bu bildiride sahne etiketleme doğruluğunu iyileştirmek için birden fazla süperpiksel bölütleme sonucunu sınıflandırıcı seviyesinde kaynaştıran bir yöntem önerilmiştir. Öncelikle basit, parametrik olmayan ve eğitim gerektirmeyen SuperParsing algoritması kullanılarak süperpiksel etiketleri için olabilirlik oranları tespit edilir. Daha sonra alternatif süperpiksel bölütleme senaryoları için hesaplanan olabilirlik oranları piksel seviyesinde kaynaştırılarak, ilgili sahnenin bölütlenmesi ve etiketlenmesi tamamlanır. Önerilen yöntem 2,688 imge ve 33 etiket içeren SIFT Flow veri kümesi üzerinde test edilmiş ve SuperParsing’den daha yüksek sınıflandırma doğruluğu elde edilmiştir.Yayın VİSKON-RS : Uzaktan algılama ile hızlı afet hasar analiz yazılımı(IEEE, 2015-06-19) Kahraman, Fatih; İmamoğlu, Mümin; Özcan, Büşra Yüksel; Huruoğlu, Cengiz; Alasağ, Tolga; Gemici, Ömer Faruk; Hocaoğlu, Muhammet A.; Ateş, Hasan FehmiAfet sonrası, acil müdahale ekiplerinin yönlendirilmesi ve iyileştirme çalışmalarının planlanması amacıyla hızlı hasar değerlendirmesine ihtiyaç duyulmaktadır. Bu çalışmada, AFAD ihtiyaçları doğrultusunda uzaktan (uzay/hava) algılama teknolojileri ile elde edilen görüntülerin afet hasar analizinde kullanılmasına yönelik VİSKON-RS yazılımı geliştirilmiştir. Geliştirilen yazılım; deprem, sel ve orman yangını gibi afet türlerinin hasar analizlerine özelleşmiş uygulamalar içermektedir. Ayrıca genel görüntü analizinde kullanılabilecek değişiklik analizi, eğitimli/eğitimsiz sınıflandırma, nesne tabanlı görüntü analizi ve doku analizi gibi uygulamalar yazılıma entegre edilmiştir. VİSKON-RS yazılımın temel amacı, afet sonrası uzaktan algılama verilerinin, açılması, işlenmesi, analiz edilmesi, sonuçların sergilenmesi ve karar destek sistemlerine aktarılması adımlarını içeren bütünleşik bir yazılım çözümü sunmaktır.Yayın Texture recognition for frog identification(ACM SIGMM, 2012-11-02) Cannavo, Flavio; Nunnari, Giuseppe; Kale, İzzet; Tek, Faik BorayThis paper describes a visual processing technique for automatic frog (Xenopus Laevis sp.) localization and identification. The problem of frog identification is to process and classify an unknown frog image to determine the identity which is recorded previously on an image database. The frog skin pattern (i.e. texture) provides a unique feature for identification. Hence, the study investigates three different kind of features (i.e. Gabor filters, granulometry, threshold set compactness) to extract texture information. The classifier is built on nearest neighbor principle; it assigns the query feature to the database feature which has the minimum distance. Hence, the study investigates different distance measures and compares their performance. The detailed results show that the most successful feature and distance measure is granulometry and weighted L1 norm for the frog identification using skin texture features.Yayın A novel approach to morphological disambiguation for Turkish(Springer-Verlag, 2012) Görgün, Onur; Yıldız, Olcay TanerIn this paper, we propose a classification based approach to the morphological disambiguation for Turkish language. Due to complex morphology in Turkish, any word can get unlimited number of affixes resulting very large tag sets. The problem is defined as choosing one of parses of a word not taking the existing root word into consideration. We trained our model with well-known classifiers using WEKA toolkit and tested on a common test set. The best performance achieved is 95.61% by J48 Tree classifier.Yayın Convolutional attention network for MRI-based Alzheimer's disease classification and its interpretability analysis(IEEE, 2021-09-17) Türkan, Yasemin; Tek, Faik BorayNeuroimaging techniques, such as Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET), help to identify Alzheimer's disease (AD). These techniques generate large-scale, high-dimensional, multimodal neuroimaging data, which is time-consuming and difficult to interpret and classify. Therefore, interest in deep learning approaches for the classification of 3D structural MRI brain scans has grown rapidly. In this research study, we improved the 3D VGG model proposed by Korolev et al. [2]. We increased the filters in the 3D convolutional layers and then added an attention mechanism for better classification. We compared the performance of the proposed approaches for the classification of Alzheimer's disease versus mild cognitive impairments and normal cohorts on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. We observed that both the accuracy and area under curve results improved with the proposed models. However, deep neural networks are black boxes that produce predictions that require further explanation for medical usage. We compared the 3D-data interpretation capabilities of the proposed models using four different interpretability methods: Occlusion, 3D Ultrametric Contour Map, 3D Gradient-Weighted Class Activation Mapping, and SHapley Additive explanations (SHAP). We observed that explanation results differed in different network models and data classes.Yayın Tweet sentiment analysis for cryptocurrencies(IEEE, 2021-10-13) Şaşmaz, Emre; Tek, Faik BorayMany traders believe in and use Twitter tweets to guide their daily cryptocurrency trading. In this project, we investigated the feasibility of automated sentiment analysis for cryptocurrencies. For the study, we targeted one cryptocurrency (NEO) altcoin and collected related data. The data collection and cleaning were essential components of the study. First, the last five years of daily tweets with NEO hashtags were obtained from Twitter. The collected tweets were then filtered to contain or mention only NEO. We manually tagged a subset of the tweets with positive, negative, and neutral sentiment labels. We trained and tested a Random Forest classifier on the labeled data where the test set accuracy reached 77%. In the second phase of the study, we investigated whether the daily sentiment of the tweets was correlated with the NEO price. We found positive correlations between the number of tweets and the daily prices, and between the prices of different crypto coins. We share the data publicly.Yayın Retinal disease classification from bimodal OCT and OCTA using a CNN-ViT hybrid architecture(Institute of Electrical and Electronics Engineers Inc., 2025-09-21) Aydın, Ömer Faruk; Tek, Faik Boray; Turkan, YaseminRetinal diseases are the leading cause of vision impairment and blindness worldwide. Early and accurate diagnosis is critical for effective treatment, and recent advances in imaging technologies such as Optical Coherence Tomography (OCT) and OCT Angiography (OCTA), have enabled detailed visualization of the retinal structure and vasculature. By leveraging these modalities, this study proposes an advanced deep learning architecture called MultiModalNet for automated multi-class retinal disease classification. MultiModalNet employs a dual-branch design, where OCTA projection maps are processed through a ResNet101 encoder, and cross-sectional slices from the OCT volume (B-scans) are analyzed using a Vision Transformer (ViT-Large). The extracted features from both branches were fused and passed through the fully connected layers for the final classification. Evaluated on the 3-class OCTA-500 dataset, which includes Age-related Macular Degeneration (AMD), Diabetic Retinopathy (DR), and Normal cases, the proposed model achieved state-of-the-art classification accuracy of 94.59 percent, significantly o utperforming single-modality baselines. This result highlights the effectiveness of integrating vascular and structural information to improve the diagnostic performance. The findings suggest that hybrid multi-modal deep learning approaches can play a transformative role in computer-aided ophthalmology, enhancing both clinical decision-making and screening workflows.Yayın Self-supervised learning of 3D structure from 2D OCT slices for retinal disease diagnosis on UK biobank scans(Institute of Electrical and Electronics Engineers Inc., 2025-09-21) Nazlı, Muhammet Serdar; Turkan, Yasemin; Tek, Faik BorayThis study presents a self-supervised learning framework for retinal disease classification using Optical Coherence Tomography (OCT) scans. To balance the contextual richness of 3D volumes with the computational efficiency of 2D architectures, we introduce a quasi-3D input generation strategy. Each input is constructed by stacking three OCT slices, sampled from channel-specific Gaussian distributions centered on the volume midplane, and arranged in a standard three-channel 2D format compatible with existing pre-trained models. These quasi-3D images are used to pre-train a Vision Transformer (ViT-Base) via a Masked Autoencoder (MAE) with a shared masking pattern, encouraging the model to reconstruct masked regions by encoding anatomical continuity across slices. Pre-training is conducted on 10,000 unlabeled OCT volumes from the UK Biobank. The encoder is then fine-tuned on the OCTA-500 dataset for three-class and four-class retinal disease classification tasks, including macular degeneration and diabetic retinopathy. The model achieves 92.57% accuracy on the three-class task, matching the performance of RETFound while using over 150 times less pre-training data and a smaller backbone.
