5 research outputs found
Ordered Logit regression model for predicting magnitude of flood along Foma River Kwara Nigeria
Flood is a natural disaster that has become a major concern to the Nigerian government. Despite the numerous hazards caused by the flood, little attention has been directed towards evaluating the flood hazards through the river condition and vulnerability components along the river areas. Hence, this study examines the river condition and vulnerability components to determine the cross-sectional variables in predicting the magnitude of flood along Foma River areas. Data extracted from Geographic Information System (GIS) and site observations were used in generating the cross-sectional variables along the river areas. From the dataset, eight crosssectional variables were obtained including 530 structures of Foma River. The Ordered Logit Regression (OLR) Models were built to predict the magnitude of flood. The model was evaluated using average values of accuracy, precision, recall, and F1-score
which were derived from the 10-fold cross validation procedure. The F1-score was able to harmonize and reduce the errors in regulating the imbalanced class distributions. It was also revealed that river watersheds, structure vulnerable status, vulnerable structures along the river, locations of bridges and culverts, sizes occupied by bridges and culverts, and river pollution are significantly contributing to the magnitude of the flood along the Foma River. This study produced a complementary approach to flood prediction along the Foma River, as well as provided the Nigerian government and practitioners a new source of information in addressing problems related to river flooding in Nigeria
Machine Learning Based Data Driven Modelling of Time Series of Power Plant Data
Accurate modeling and simulation of data collected from a power plant system are important
factors in the strategic planning and maintenance of the unit. Several non-linearities
and multivariable couplings are associated with real-world plants. Therefore, it becomes
almost impossible to model the system using conventional mathematical equations. Statistical
models such as ARIMA, ARMA are potential solutions but their linear nature cannot
very well t a system with non-linear, multivariate time series data. Recently, deep learning
methods such as Arti cial Neural Networks (ANNs) have been extensively applied for
time series forecasting. ANNs in contrast to stochastic models such as ARIMA can uncover
the non-linearities present underneath the data.
In this thesis, we analyze the real-time temperature data obtained from a nuclear power
plant, and discover the patterns and characteristics of the sensory data. Principal Component
Analysis (PCA) followed by Linear Discriminant Analysis (LDA) is used to extract
features from the time series data; k-means clustering is applied to label the data instances.
Finite state machine representation formulated from the clustered data is then used to
model the behaviour of nuclear power plants using system states and state transitions. Dependent
and independent parameters of the system are de ned based on co-relation among
themselves. Various forecasting models are then applied over multivariate time-stamped
data. We discuss thoroughly the implementation of a key architecture of neural networks,
Long Short-Term Neural Networks (LSTMs). LSTM can capture nonlinear relationships
in a dynamic system using its memory connections. This further aids them to counter
the problem of back-propagated error decay through memory blocks. Poly-regression is
applied to represent the working of the plant by de ning an association between independent
and dependent parameters. This representation is then used to forecast dependent
variates based on the observed values of independent variates. Principle of sensitivity
analysis is used for optimisation of number of parameters used for predicting. It helps in
making a compromise between number of parameters used and level of accuracy achieved
in forecasting.
The objective of this thesis is to examine the feasibility of the above-mentioned forecasting
techniques in the modeling of a complex time series of data, and predicting system
parameters such as Reactor Temperature and Linear Power based on past information. It
also carries out a comparative analysis of forecasts obtained in each approach
A SA-ANN-Based Modeling Method for Human Cognition Mechanism and the PSACO Cognition Algorithm
Artificial neural networks (ANNs) are the important approaches for researching human cognition process. However, current ANNs-based cognition methods cannot address the problems of complex information understanding and fault-tolerant learning. Here we present a modeling method for cognition mechanism based on a simulated annealing–artificial neural network (SA-ANN). Firstly, the relationship between SA processing procedure and cognition knowledge evolution is analyzed, and a SA-ANN-based inference model is set up. Then, based on the inference model, a Powell SA with combinatorial optimization (PSACO) algorithm is proposed to improve the clustering efficiency and recognition accuracy for the cognition process. Finally, three groups of numerical instances for knowledge clustering are provided, and three comparative experiments are performed by self-developed cognition software. The simulated results show that the proposed method can increase the convergence rate by more than 20%, compared with the back-propagation (BP), SA, and restricted Boltzmann machines based extreme learning machine (RBM-ELM) algorithms. The comparative cognition experiments prove that the method can obtain better performances of information understanding and fault-tolerant learning, and the cognition accuracies for original sample, damaged sample, and transformed sample can reach 99.6%, 99.2%, and 97.1%, respectively