• 전기전자학회논문지
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• 제24권3호
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• pp.766-776
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• 2020

최근 기계학습에 대한 관심이 높아지고 연구가 활성화됨에 따라 다양한 기계학습 모델에서 최적의 하이퍼 파라미터 조합을 찾는 것이 중요해지고 있다. 본 논문에서는 다양한 하이퍼 파라미터 중에서 옵티마이저에 중점을 두고, 다양한 데이터에서 주요 옵티마이저들의 성능을 측정하고 비교하였다. 특히, 가장 기본이 되는 SGD부터 Momentum, NAG, AdaGrad, RMSProp, AdaDelta, Adam, AdaMax, Nadam까지 총 9개의 옵티마이저의 성능을 MNIST, CIFAR-10, IRIS, TITANIC, Boston Housing Price 데이터를 이용하여 비교하였다. 실험 결과, 전체적으로 Adam과 Nadam을 사용하였을 때 기계학습 모델의 손실 함숫값이 가장 빠르게 감소하는 것을 확인할 수 있었으며, F1 score 또한 높아짐을 확인할 수 있었다. 한편, AdaMax는 학습 중에 불안정한 모습을 많이 보여주었으며, AdaDelta는 다른 옵티마이저들에 비하여 수렴 속도가 느리며 성능이 낮은 것을 확인할 수 있었다.

• International Journal of Computer Science & Network Security
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• 제24권2호
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• pp.101-112
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• 2024

Telugu language is considered as fourth most used language in India especially in the regions of Andhra Pradesh, Telangana, Karnataka etc. In international recognized countries also, Telugu is widely growing spoken language. This language comprises of different dependent and independent vowels, consonants and digits. In this aspect, the enhancement of Telugu Handwritten Character Recognition (HCR) has not been propagated. HCR is a neural network technique of converting a documented image to edited text one which can be used for many other applications. This reduces time and effort without starting over from the beginning every time. In this work, a Unicode based Handwritten Character Recognition(U-HCR) is developed for translating the handwritten Telugu characters into English language. With the use of Centre of Gravity (CG) in our model we can easily divide a compound character into individual character with the help of Unicode values. For training this model, we have used both online and offline Telugu character datasets. To extract the features in the scanned image we used convolutional neural network along with Machine Learning classifiers like Random Forest and Support Vector Machine. Stochastic Gradient Descent (SGD), Root Mean Square Propagation (RMS-P) and Adaptative Moment Estimation (ADAM)optimizers are used in this work to enhance the performance of U-HCR and to reduce the loss function value. This loss value reduction can be possible with optimizers by using CNN. In both online and offline datasets, proposed model showed promising results by maintaining the accuracies with 90.28% for SGD, 96.97% for RMS-P and 93.57% for ADAM respectively.