31 research outputs found
Sleep heart rate variability analysis and k-Nearest neighbours classification of primary insomnia
No full textPhase amplitude coupling of theta-gamma EEG frequency bands in sleep apnoea
No full textPhase amplitude coupling of neuronal oscillations has been suggested to link with upper brain functions such as cognitive and memory process. It is suggested that cross frequency coupling (CFC) occurred when the amplitude of fast oscillation is modulated by the phase of slow oscillation. In this study, we assess CFC in terms of Modulation Index (MI) of theta, low gamma (LG) and high gamma (HG) in sleep stages N1, N2, N3 and REM of healthy and sleep apnoea patients. The results showed theta phase modulated more the HG band in all sleep stages. Theta-HG coupling was more pronounced in the sleep apnoea as compared to the healthy
Double density wavelet for EEG signal denoising
No full textEEG signals usually were contaminated with unwanted artefacts that may hide some valuable information in the signals. In this paper, we implemented wavelet based image processing techniques known as 1-D Double Density and 1-D Double Density Complex for denoising EEG signals at various windows size. The performances of these methods were compared and evaluated by calculating the Root Mean Square Error (RMSE). The minimum RMSE was achieved at the threshold value of 20. The 1-D Double Density Complex was outperformed 1-D Double Density and was effective in EEG signals denoising
A Review of Methods to Characterize and Classify Sleep, Depression and Schizophrenia Disorders
No full textElectrophysiological signal segmentation for EEG frequency bands and heart rate variability analysis
No full textBiological signals like Electroencephalography (EEG) and Electrocardiography (ECG) provide very useful information related to brain and heart condition. Spectral analysis of EEG frequency bands and analysis of Heart Rate Variability (HRV) of ECG signal are largely used as a biomarker in studying various pathological conditions. However, the studies on EEG and HRV frequency bands analysis have shown inconsistency in the size of segment length used to extract the features. In the power spectral analysis, the trade-off between time and frequency resolution remain unsolved issue. To increase a frequency resolution and reduced a spectral leakage, a long segment of input data is necessary. However, for a stationary consideration a short segment data is needed. Therefore, in this study we examine the effect of segmentation time window and overlapping in spectral analysis of EEG frequency bands and HRV. The EEG and ECG signals used in this study are collected from the healthy and sleep apnea patients. Five features (delta, theta, alpha, sigma and beta) are extracted from EEG frequency bands and three (LFnu,HFnu, LF/HF) from the HRV by using spectral analysis at various window size and overlapping percentage. The results show the optimum window size for EEG is achieved at 10 sec and 120 sec for HRV analysis
Supplier selection procedure in telecommunication industry
Get PDFManaging supply chain is important for every organization because it has become a major element in a global economy. The supply chain is a primary system that moves the products or services from supplier to customer. Poor performance in delivering the services will essentially affect customer satisfaction. Previous studies have shown the effects of supplier selection on the organization performance in the services or products delivery. This research focuses on civil infrastructure and pulling cable suppliers in one of the telecommunication players in Malaysia and also on its supplier selection procedure, which is known as Price Rate Table (PRT). This paper initially reviewed the concepts of PRT pool and PRT zoning. We then assessed the level of staff satisfaction on PRT and also its advantages and disadvantages in terms of project performance. This assessment was conducted qualitatively via semi structured interview to a specific project team in the organization. Results showed that for small projects the PRT concept has offered more advantages than disadvantages in terms of project performance. On the other hand, the disadvantages are emphasized more for mega and urgent projects. In this paper, we proposed two selection processes to overcome the issues and also evaluated the processes using strategy canvas. Only the best selection process upon the highest accumulated point obtained is recommended to be adopted in the current organization
Sleep heart rate variability analysis and k-nearest neighbours classification of primary insomnia
Get PDFThe Heart Rate Variability (HRV) of many sleep disorders shows an alteration of the sympathovagal balance of the Autonomous Nervous System (ANS). Primary insomnia refers to the difficulty in initiating or maintaining sleep that is not caused by other illnesses or substances. The HRV of primary insomnia shows inconsistent findings although it is believed to impair the HRV variables. This study compares the HRV changes during different sleep stages and evaluates the k-nearest neighbours (kNN) classifier using the HRV features for primary insomnia classification. The time and frequency HRV variables were extracted from sleep ECG signals of 10 primary insomnia patients and 10 healthy controls during four sleep stages - N1, N2, N3 and REM. The Mann-Whitney U-test was conducted to evaluate the existence of statistical significant differences between the two groups at different sleep stages. The kNN classifier was adapted for the classification tool. Only the LF index of HRV was significantly higher in the primary insomnia patients compared to the healthy subjects. The classification accuracy of kNN was at 75% when both the HRV time and frequency variables were accounted as inputs to the classifier
Process improvement methodology selection in manufacturing: A literature review perspective
Get PDFProblems in manufacturing have always been a hurdle for leadership, engineers, and professionals. They can lead to low productivity, poor quality, high costs, and ultimately loss of customers. Problems should be prevented by fair means and following well-established methodologies of continuous process improvement. The present paper addresses this topic, which in both academic and professional literature has been discussed from one single angle–that is, how to use a specific methodology in a certain situation. From that perspective, researchers from academia and consultancy promote the use of a particular method. One of the greatest challenges to researchers and practitioners in manufacturing is to select the right methodology for problem-solving and process improvement. The present paper attempts to address this issue from a literature review perspective. The approach followed is based on the fact that understanding the attributes of process improvement methodologies reported in the open literature and their linkages to the main phases of the continuous improvement process will provide insights on how the selection of the methodologies can be carried out in real manufacturing situations
Review of Taxi Cab Service Optimization in Petaling Jaya, Malaysia Based On Demand and Offer
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