Ephrem Admasu Yekun

Ephrem Admasu Yekun, Alem H. Fitwib, Selvi Karpaga Subramaniand et al.

Owing to its minimal pollution and efficient energy use, wind energy has become one of the most widely exploited renewable energy resources. The successful integration of wind power into the grid system is contingent upon accurate wind speed forecasting models. However, the task of wind speed forecasting is challenging due to the inherent intermittent characteristics of wind speed. In this paper, a hybrid machine learning approach is developed for predicting short-term wind speed. First, the wind data was decomposed into modal components using Successive Variational Mode Decomposition (SVMD). Then, each sub-signal was fitted into a Least Squares Support Vector Machines (LSSVM) model, with its hyperparameter optimized by a novel variant of Quantum-behaved Particle Swarm Optimization (QPSO), QPSO with elitist breeding (EBQPSO). Second, the residuals making up for the differences between the original wind series and the aggregate of the SVMD modes were modeled using long short-term model (LSTM). Then, the overall predicted values were computed using the aggregate of the LSSVM and the LSTM models. Finally, the performance of the proposed model was compared against state-of-the-art benchmark models for forecasting wind speed using two separate data sets collected from a local wind farm. Empirical results show significant improvement in performance by the proposed method, achieving a 1.21% to 32.76% reduction in root mean square error (RMSE) and a 2.05% to 40.75% reduction in mean average error (MAE) compared to the benchmark methods. The entire code implementation of this work is freely available in Github.

Ephrem Admasu Yekun, Petros Reda Samsom

Change detection is a fast-growing discipline in the areas of computer vision and remote sensing. In this work, we designed and developed a variant of convolutional neural network (CNN), known as Siamese CNN to extract features from pairs of Sentinel-2 temporal images of Mekelle city captured at different times and detect changes due to urbanization: buildings and roads. The detection capability of the proposed was measured in terms of overall accuracy (95.8), Kappa measure (72.5), recall (76.5), precision (77.7), F1 measure (77.1). The model has achieved a good performance in terms of most of these measures and can be used to detect changes in Mekelle and other cities at different time horizons undergoing urbanization.

Ephrem Admasu Yekun, Abrahaley Teklay

One of the important measures of quality of education is the performance of students in the academic settings. Nowadays, abundant data is stored in educational institutions about students which can help to discover insight on how students are learning and how to improve their performance ahead of time using data mining techniques. In this paper, we developed a student performance prediction model that predicts the performance of high school students for the next semester for five courses. We modeled our prediction system as a multi-label classification task and used support vector machine (SVM), Random Forest (RF), K-nearest Neighbors (KNN), and Mult-layer perceptron (MLP) as base-classifiers to train our model. We further improved the performance of the prediction model using state-of-the-art partitioning schemes to divide the label space into smaller spaces and use Label Powerset (LP) transformation method to transform each labelset into a multi-class classification task. The proposed model achieved better performance in terms of different evaluation metrics when compared to other multi-label learning tasks such as binary relevance and classifier chains.