354 research outputs found
R PEAK DETERMINATION USING A WDFR ALGORITHM AND ADAPTIVE THRESHOLD
The determination of the R peak position in the ECG signal helps physicians not only to know the heart rate per minute, but also to monitor the patient’s health related to heart disease. This paper proposes a system to accurately determine the R peak position in the ECG signal. The system consists of a pre-processing block for filtering out noise using a WDFR algorithm and highlighting the amplitude of the R peak and a threshold value is calculated for determining the R peak. In this research, the MIT-BIH ECG dataset with 48 records are used for evaluation of the system. The results of the SEN, +P, DER and ACC parameters related to the system quality are 99.70%, 99.59%, 0.70% and 99.31%, respectively. The obtained performance of the proposed R peak position determination system is very high and can be applied to determine the R peak of the ECG signal measuring devices in practice
Stochastic graph partitioning: quadratic versus SOCP formulations
International audienceWe consider a variant of the graph partitioning problem involving knapsack constraints with Gaussian random coefficients. In this new variant, under this assumption of probability distribution, the problem can be traditionally formulated as a binary SOCP for which the continuous relaxation is convex. In this paper, we reformulate the problem as a binary quadratic constrained program for which the continuous relaxation is not necessarily convex. We propose several linearization techniques for latter: the classical linearization proposed by Fortet (Trabajos de Estadistica 11(2):111–118, 1960) and the linearization proposed by Sherali and Smith (Optim Lett 1(1):33–47, 2007). In addition to the basic implementation of the latter, we propose an improvement which includes, in the computation, constraints coming from the SOCP formulation. Numerical results show that an improvement of Sherali–Smith’s linearization outperforms largely the binary SOCP program and the classical linearization when investigated in a branch-and-bound approach
Performance Investigation of High-Speed Train OFDM Systems under the Geometry-Based Channel Model
The high-speed of train (HST) in combination with the high carrier frequency of HST systems leads to the severe inter carrier interference (ICI) in the HST orthogonal frequency division multiplexing (HST-OFDM) systems. To avoid the complexity in OFDM receiver design for ICI eliminations, the OFDM system parameters such as symbol duration, signal bandwidth, and the number of subcarriers should be chosen appropriately. This paper aims to propose a process of HST-OFDM system performance investigation to determine these parameters in order to enhance spectral efficiency and meet a given quality-of-service (QoS) level. The signal-to-Âinterference-Âplus-Ânoise ratio (SINR) has been used as a figure of merit to analyze the system performance instead of signal-to-noise ratio (SNR) as most of recent research studies. Firstly, using the non-stationary geometry-based stochastic HST channel model, the SINR of each subcarrier has been derived for different speeds of the train, signal bandwidths, and number of subcarriers. Consequently, the system capacity has been formulated as the sum of all the single channel capacity from each sub-carrier. The constraints on designing HST-OFDM system parameters have been thoughtfully analyzed using the obtained expressions of SINR and capacity. Finally, by analyzing the numerical results, the system parameters can be found for the design of HST-OFDM systems under different speeds of train. The proposed process can be used to provide hints to predict performance of HST communication systems before doing further high cost implementations as hardware designs
Factors Impact on Tourist Destination Loyalty: A Case Study in Ho Chi Minh City.
The purpose of this paper is to define and measure key factors regarding to tourist destination loyalty in Ho Chi Minh city (Viet Nam).This study has used qualitative and quantitative research approaches: (i) qualitative research was carried out through focus group discussions with 10 tourists, and (ii) quantitative
research was conducted through direct interviews with 305 tourist in Ho Chi Minh city (Vietnam). The results show that: (i) tourist destination loyalty is affected by service quality, destination image, tourist satisfaction; and (ii) tourist satisfaction is affected by service quality and a destination’s image. However, the research
has certain limitations: (i) Due to limited resources in conducting research, the sample size consisted of 305 tourist, (ii) This study conducted a sampling technique method of using direct interview methods from tourists in Ho Chi Minh city, Viet Nam, but the sample may not have been representative enough
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