Wavelet-Based Kernel Construction for Heart Disease Classification

© 2019 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERINGHeart disease classification plays an important role in clinical diagnoses. The performance improvement of an Electrocardiogram classifier is therefore of great relevance, but it is a challenging task too. This paper proposes a novel classification algorithm using the kernel method. A kernel is constructed based on wavelet coefficients of heartbeat signals for a classifier with high performance. In particular, a wavelet packet decomposition algorithm is applied to heartbeat signals to obtain the Approximation and Detail coefficients, which are used to calculate the parameters of the kernel. A principal component analysis algorithm with the wavelet-based kernel is employed to choose the main features of the heartbeat signals for the input of the classifier. In addition, a neural network with three hidden layers in the classifier is utilized for classifying five types of heart disease. The electrocardiogram signals in nine patients obtained from the MIT-BIH database are used to test the proposed classifier. In order to evaluate the performance of the classifier, a multi-class confusion matrix is applied to produce the performance indexes, including the Accuracy, Recall, Precision, and F1 score. The experimental results show that the proposed method gives good results for the classification of the five mentioned types of heart disease.Peer reviewedFinal Published versio

Factors influencing the urge to buy impulsively of Vietnamese online buying customers towards Biti’s Hunter sport shoes

Our study investigates the factors that drive Vietnamese online shoppers in Ho Chi Minh City (HCMC) to make impulsive purchases of Biti's Hunter sports shoes (BHS), using the Stimulus-Organism-Response (S-O-R) theory and the Technology Acceptance Model (TAM). Mixed methods are applied: in-depth interviews with ten regular online shoppers and focus group discussions with e-commerce managers for qualitative data collection, and survey techniques to gather quantitative data from 319 online shoppers. Data analysis was performed using SPSS 22.0 and AMOS 22.0. Our findings reveal five factors as a stimulus - visual appeal, website ease of use, product availability, portability, and social influence – and three factors as an organism - instant gratification, impulsiveness, and trust, that lead to the response of urge to buy impulsively. Significant positive effects are found among these constructs, except the relationship between portability and impulsiveness, visual appeal, social influence, trust, instant gratification, and urge to buy impulsively

Calculation of the wave parameters for sea dyke design and upgrading

Sea dyke system is the effective mean for protecting the coastal low-lying areas from storm attack (the most dangerous storm induced phenomena are storm wave and surges). The coastal zone of Vietnam is blessed with wide variety of natural resources but at the same time, it is also a highly storm hazard-prone region. The storm number 7 (DAMREY) arrived in the East Sea from 26th to 28th of September 2005 and hit the south part of Red river delta coastal zone and caused sea dykes breaches at some stretches along the sea dyke system of the Nam Dinh province and big property damages of the local communes. In order to cope with the storm activity which is reinforced in the future by climate change, a Science Technology program on the sea dyke upgrading from Quang Ninh to Quang Nam provided by the Ministry of Agriculture and Rural Development has been implemented from April 2007. One of the program’s project is “Determining the wave heights for sea dyke designed along the coastal line from Quang Ninh to Quang Nam” with the object to propose a method for the calculation of the wave parameters with appropriate accuracy, simple for used and suitable for the natural condition of the different sectors of coastal line of Viet Nam from Quang Ninh to Quang Nam provinces and to upgrade and fulfill the wave calculation guideline for sea dyke design and upgrading. In the paper, the authors present the results of the project concerning the input data, wave models and the calculated wave parameters with different returning periods for 5 sectors along the coastal line from Quang Ninh to Quang Nam. The obtained results afford the promising of using in the sea dyke design and upgrading

Drivers of rainfall trends in and around Mainland Southeast Asia

Observational rain gauge/satellite and reanalysis datasets since the 1950s are evaluated for trends in mean and extreme rainfall in and around Mainland Southeast Asia (MSEA). Rain gauge data indicate strong increases exceeding 50% in both annual mean precipitation and various extreme precipitation indices over Vietnam and the northwestern part of the peninsula since 1979. The remote influence of ENSO may partially explain the recent precipitation trend toward a more intense regional hydrological cycle, in response to predominant La Niña states over recent decades. Increasing precipitation in MSEA is also associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity center toward MSEA over 1979–2018. Warming-driven evaporation increases were obtained over the adjacent seas typically feeding precipitation over MSEA associated with a shift toward predominantly positive phases of the two major natural climate variability modes of the tropical Indian Ocean, namely the Indian Ocean Dipole and the Indian Ocean Basin Mode. A moisture budget analysis using ERA5 re-analysis data showed increasing oceanic moisture transports along the typical winter and summer moisture pathways toward the MSEA. However, results show that during summer the major part of increased moisture from the oceanic moisture sources ends up as precipitation over the oceanic regions adjacent to MSEA with ERA5 not being able to produce the observed positive trends in summer continental precipitation. On the other hand, ERA5 reveals pronounced increases in winter precipitation over the MSEA, in accordance with rain-gauge data, associated with strongly increasing transport of moisture originated from the western tropical Pacific and the South China Sea