Arama Sonuçları

Listeleniyor 1 - 5 / 5
  • Yayın
    Univariate margin tree
    (Springer, 2010) Yıldız, Olcay Taner
    In many pattern recognition applications, first decision trees are used due to their simplicity and easily interpretable nature. In this paper, we propose a new decision tree learning algorithm called univariate margin tree, where for each continuous attribute, the best split is found using convex optimization. Our simulation results on 47 datasets show that the novel margin tree classifier performs at least as good as C4.5 and LDT with a similar time complexity. For two class datasets it generates smaller trees than C4.5 and LDT without sacrificing from accuracy, and generates significantly more accurate trees than C4.5 and LDT for multiclass datasets with one-vs-rest methodology.
  • Yayın
    Subset selection for tuning of hyper-parameters in artificial neural networks
    (IEEE, 2017) Aki, K.K.Emre; Erkoç, Tuğba; Eskil, Mustafa Taner
    Hyper-parameters of a machine learning architecture define its design. Tuning of hyper-parameters is costly and for large data sets outright impractical, whether it is performed manually or algorithmically. In this study we propose a Neocognitron based method for reducing the training set to a fraction, while keeping the dynamics and complexity of the domain. Our approach does not require processing of the entire training set, making it feasible for larger data sets. In our experiments we could successfully reduce the MNIST training data set to less than 2.5% (1,489 images) by processing less than 10% of the 60K images. We showed that the reduced data set can be used for tuning of number of hidden neurons in a multi-layer perceptron.
  • Yayın
    Statistical tests using hinge/ε-sensitive loss
    (Springer-Verlag, 2013) Yıldız, Olcay Taner; Alpaydın, Ahmet İbrahim Ethem
    Statistical tests used in the literature to compare algorithms use the misclassification error which is based on the 0/1 loss and square loss for regression. Kernel-based, support vector machine classifiers (regressors) however are trained to minimize the hinge (ε-sensitive) loss and hence they should not be assessed or compared in terms of the 0/1 (square loss) but with the loss measure they are trained to minimize. We discuss how the paired t test can use the hinge (ε-sensitive) loss and show in our experiments that doing that, we can detect differences that the test on error cannot detect, indicating higher power in distinguishing between the behavior of kernel-based classifiers (regressors). Such tests can be generalized to compare L > 2 algorithms.
  • Yayın
    Animal sound classification using a convolutional neural network
    (IEEE, 2018-12-06) Şaşmaz, Emre; Tek, Faik Boray
    In this paper, we investigate the problem of animal sound classification using deep learning and propose a system based on convolutional neural network architecture. As the input to the network, sound files were preprocessed to extract Mel Frequency Cepstral Coefficients (MFCC) using LibROSA library. To train and test the system we have collected 875 animal sound samples from an online sound source site for 10 different animal types. We report classification confusion matrices and the results obtained by different gradient descent optimizers. The best accuracy of 75% was obtained by Nesterov-accelerated Adaptive Moment Estimation (Nadam).
  • Yayın
    Odaklanan nöron
    (IEEE, 2017-06-27) Çam, İlker; Tek, Faik Boray
    Geleneksel yapay sinir ağında topoloji eğitim sırasında değişebilecek esnekliğe sahip değildir. Ağda her bir nöron ve bağımsız bağlantı katsayıları çözüm işlevinin bir parçasıdır. Bu bildiride önerdiğimiz odaklanabilir nöron birbirine bağımlı katsayıların çekildiği bir odaklayıcı işlevden yararlanır. Nöron odak pozisyonu ve açıklığını değiştirerek aktivasyon topladığı nöronları değiştirebilir. Bu özelliği sayesinde esnek ve dinamik bir ağ topolojisi oluşturabilir ve standart geriye yayılım algoritmasıyla eğitilebilir. Yapılan deneylerde odaklanabilir nöronlarla kurulan bir ağ yapısının, tümüyle bağlı yapay sinir ağına göre daha yüksek başarı elde ettiği gözlenmiştir.