ABSTRACT
BACKGROUND: Mounting novel solutions for conspicuous neurodegenerative disorders that grow consistently, such as Alzheimer's disease, rely on tracking and identifying disease development, improvement, and progression. Compared to many clinical or survey-based detection methods, early Alzheimer's stage detection can be possible through computer-based MR brain images and discrete stochastic processes. AIM: In the case of Alzheimer's stage progression, the existing models illustrate that the learning problem comprises two issues: estimating posterior probabilities of the Alzheimer's stage and computing conditioned statistics of the Alzheimer's end-stage. The proposed model overcomes these issues by restructuring the estimation problem as EM-centered CT- HMM. METHODS: This paper proposes a novel framework model with two phases; the first phase covers the feature extraction of magnetic resonance imaging based on many computer vision methods known as a collection of bag-of-features (BoF). In the second phase, the EM-centered learning method is used for the continuous-time hidden Markov model (CT-HMM), an efficient approach to modeling Alzheimer's disease progression with time and stages. The proposed CT-HMM is implemented with eight Alzheimer's stages (source: ADNI) to visualize and predict the stage progression of the ADNI MRI dataset. RESULTS: The proposed model reported the transition posterior probability as 0.765 (high to low stage progression) and 0.234 (low to high stage progression). The model's accuracy and F1 score are estimated as 97.13 and 96.51, respectively. CONCLUSION: The proposed model's accuracy and evaluation metrics reported higher results in the work on Alzheimer's stage progression and prediction.
ABSTRACT
Corn has great importance in terms of production in the field of agriculture and animal feed. Obtaining pure corn seeds in corn production is quite significant for seed quality. For this reason, the distinction of corn seeds that have numerous varieties plays an essential role in marketing. This study was conducted with 14,469 images of BT6470, Calipso, Es_Armandi, and Hiva types of corn licensed by BIOTEK. The classification of images was carried out in three stages. At the first stage, deep feature extraction of the four types of corn images was performed with the pretrained CNN model SqueezeNet 1000 deep features were obtained for each image. In the second stage, in order to reduce these features obtained from deep feature extraction with SqueezeNet, separate feature selection processes were performed with the Bat Optimization (BA), Whale Optimization (WOA), and Gray Wolf Optimization (GWO) algorithms among optimization algorithms. Finally, in the last stage, the features obtained from the first and second stages were classified by using the machine learning methods Decision Tree (DT), Naive Bayes (NB), multi-class Support Vector Machine (mSVM), k-Nearest Neighbor (KNN), and Neural Network (NN). In the classification processes of the features obtained in the first stage, the mSVM model has achieved the highest classification success with 89.40%. In the second stage, as a result of the classifications performed through the active features selected by using three types of feature selection algorithms (BA, WOA, GWO), the classification success obtained with the mSVM model was 88.82%, 88.72%, and 88.95%, respectively. The classification accuracies of the tested methods and the classification accuracies obtained in the first stage are close to each other in terms of classification success. However, with the algorithms used in feature selection, successful classification processes have been carried out with fewer features and in a shorter time. The results of the study, in which classification was carried out in the inexpensive, the objective, and the shorter time of processing for the corn types, present a different perspective in terms of classification performance.
