A. Q. Abbasi, and W. A. Loun. Symbolic Time Series Analysis of Temporal Gait Dynamics. In Journal of Signal Processing Systems, vol. 74(3) , 2014
Signals obtained from biological systems exhibit pronounced complexity. The patterns of change contain valu- able information about the dynamics of underlying control mechanism of the complex biological systems. Human gait is a complex process with multiple inputs and numerous outputs. Various complexity analysis tools have been proposed to extract information from human gait time series. In this study, we used recently developed threshold based symbolic entropy to compare the spontaneous output of the human locomotors system during constrained and metronomically paced walking protocols. For that purpose, stride interval time series of healthy subjects who walked for 1 h at normal, slow and fast rates under different conditions was transformed into symbol sequences. Normalized corrected Shannon entropy (NCSE) was computed from the symbol sequences of the stride inter- val time series. The findings indicated that the unprompted output of human locomotors system is more complex during unconstrained normal walking as compared with slow, fast or metronomically paced walking
This article analyzes the tools and methods used in the analysis of emotions from text for the purpose of managing society. It illustrates the influence of emotions on the management of people, society and businesses processes. Their importance and the changes that occurs over time in the processes of managing society. The role that social networks plays in managing society and the methods they uses. We researched different websites and software, observed their mechanisms for data collection, its analysis and use for the purpose of managing society. In general, we analyze the most common methods, the factors that affects the choice of a particular method, their influence and based on our analy-sis, give recommendations for improving the process of analyzing emotions for the purpose of managing society.
Electroencephalography (EEG) is a method to measure the electrical activity of brain signals by electrodes attached to the scalp at multiple locations. In this study we used the EEG signals of Alcoholic and Control subjects were obtained from Machine Learning repository according to the 10-20 International System. There were 29 subjects from control group and 29 from alcoholic comprising of electrodes from different brain lobes such as Central Lobe (C3, C4), Frontal (F3, F4, F7, F8), Occipital Lobe (O1, O2), Parietal Lobe (P3, P4), Temporal Lobe (T7) and Front Polar (Fp1, Fp2). In the first phase, the nonlinear complexity based features are computed such as Approximate Entropy, Sample Entropy and Wavelet Entropy. These features for each electrode are passed as input to the Machine Learning classifiers such as Multilayer Perceptron (MPL), K-nearest Neighbor (KNN) and LIB Support Vector Machine (SVM) to classify for alcoholic and control group. The highest accuracy was obtained using MLP of 98.22 % at electrode C3. Moreover, above 90% accuracy was obtained using MPL at electrode C3, C4, F7; KNN at electrodes C3, C4, F7 and LIB SVM at electrodes C3, C4, F7 where KNN gives highest accuracy of 97.67% at electrode C4 and LIB SVM an accuracy of 94.67 % at electrode F7. Secondly, the ensemble methods are employed such as Minimum, Maximum, Sum, Average, Product, Majority Vote, Bayes, Decision Template and Dempster Shefer Fusion. Using ensemble methods most electrodes depicted higher accuracy than individual classifier such as Electrode F4, Fp2, O1, O2 and T7. While electrode C3 the ensemble methods Moving Average, DT, DFT gives highest accuracy of 98.22% and at electrodes C4 Moving Average, Sum, Average, DT, DFT provided an accuracy of 97.11%.
A. Q. Abbasi, and W. Aziz. Human Gait Analysis: Analysis of Human Gait Dynamics Using Symbolic Time Series Analysis Method. LAP LAMBERT Academic Publishing, Pakistan. 2013.
Signals obtained from biological systems exhibit pronounced complexity. The patterns of change contain valuable information about the dynamics of underlying control mechanism of the complex biological systems. Human gait is a complex process with multiple inputs and numerous outputs.Various complexity analysis tools have been proposed to extract information from human gait time series. In this study, we used recently developed threshold based symbolic entropy to compare the spontaneous output of the human locomotors system during constrained and metronomically paced walking protocols. The findings indicated that the unprompted output of human locomotors system is more complex during unconstrained normal walking as compared with slow, fast or metronomically paced walking. The results was compared with the Multiscale Entropy (MSE) Analysis proposed and we concluded that the Symbolic Analysis is more robust than multiscale entropy method as well as our method is also useful for smaller time series whereas MSE is not suitable for shorter time series.
Conference Contributions (2)
A. Q. Abbasi, W. Aziz, S. Saeed, I. Ahmed, and L. Hussain. Comparative study of multiscale entropy analysis and symbolic time series analysis when applied to human gait dynamics. In International Conference on Open Source Systems and Technologies, pp. 126-132, 2013
The chronological vacillations in the stride to stride interval provide a noninvasive method to assess the influence of malfunction of human gait and its alterations with disease and age. To extract information from the human stride interval, various complexity analysis techniques have been proposed. In the present study, the comparison of two recently developed complexity analysis methodologies: multiscale entropy (MSE) and symbolic entropy (SyEn) has been made. These techniques were applied to stride interval time series data of human gait walking at normal and metronomically paced stressed conditions. Wilcoxon-rank-sum test (Mann-Whitney-Wilcoxon (MWW) test) was used to find the significant difference between the groups. For each method of analysis, parameters were adjusted to optimize the separation of the groups. The symbolic entropy method provided maximum separation at wide range of threshold values and this measure was found to be more robust for analyzing the human gait data as compared to multiscale entropy in the presence of dynamical and observational noise. The results of this study can have implication modeling physiological control mechanism and for quantifying human gait dynamics in physiological and stressed conditions.
L. Hussain, W. Aziz, S. A. Nadeem, and A. Q. Abbasi. Classification of Normal and Pathological Heart Signal Variability Using Machine Learning Techniques. In International Journal of Darshan Institute on Engineering Research and Emerging Technology, vol. 3(2) , pp. 13-19, 2014
The guide Heart rate signals provide valuable information for assessing the state of autonomic nervous system that control functioning of heart. Heart rate variability analysis is an important non-invasive tool that has been widely used for assessing autonomic control of heart using linear and non-linear techniques since last three decades. Different methods used to detect these beats include ECG, blood pressure etc. but ECG has great importance because it gives a complete and clear waveform. Heart rate variability analysis is a tool that assesses the autonomic nervous system. It is based on the measurement of changing heart rate signals. In past two decades a large number of research efforts were made and a number of techniques were proposed for heart rate variability. In this study, the techniques used for HRV analysis includes linear (time and frequency domain) and non-linear techniques. We have used different classifiers and their methods to check heart rate variations in healthy cases and diseased cases. Methods showing highest accuracy include Naïve Bayes method of Bayes classifier; sequential minimal optimization (SMO) of functions classifier, lazy locally weighted learning (LWL) method, AdaBoost and logical model tree. Among all these methods LMT (logical model tree) is considered as best method with the accuracy level of 92.5%. In this study 10 folds cross-validation was used as test option. Cross-validation is a technique to assess the accuracy of results where the goal is predicted. In 10 folds cross-validation 10 times repetition occurs and the result is obtained by taking mean accuracy.
M.Phil. in Computer Science from University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
Master Thesis done at UAJK under the supervision of Porf. Dr. Wajid Aziz Loun. Title: “Symbolic Time Series Analysis of Human Gait Dynamics”.
Lecturer at Women University of Azad Jammu and Kashmir Bagh, Pakistan
HEC/DAAD Scholar for PhD studies.
PhD student at KIT from October 2018.
Sensor and Signal Processing, Biomedical Time Series Classification & Prediction, Gait Analysis