Volume 21, Issue 2 | |
Biomedical systems | |
R-peak Detection in Electrocardiogram Signals Using Continuous Wavelet Transform | 165-178 |
Seyed Reza Razavi, Mohammad Hossein Doost Mohammadi [ +/- abstract ][ full text ] | |
In this paper, an efficient wavelet-based method is proposed to detect the R-peak from QRS complex. At first, a preprocessing step is taken to remove high frequency noise of electrocardiogram (ECG) data. Then, continuous wavelet transform (CWT) is applied to the signal and the R-peaks of QRS complexes are detected with acceptable accuracy using special thresholding method. The detection performance of the proposed algorithm is evaluated against the MIT-BIH Arrhythmia Database. The numerical results indicated that the proposed method achieved a detection rate of 99.72% over all standard database used for evaluation. Also, evaluating the performance of the proposed algorithm on ECG signal with poor signal quality indicated the reliability of this algorithm even under the condition of poor SNR. Finally, the accuracy of detection rate is proven by comparing the proposed algorithm with some other methods from different literatures. | |
An Approach to Modeling Drug Release from Polymersome Nanoparticles Based on PNIPAM-g-PEO Graft Copolymer | 179-188 |
Rumiana Blagoeva, Assen Nedev, Victoria Michailova [ +/- abstract ][ full text ] | |
The recently proposed by the authors numerical approach to modelling of drug release from polymersome nanoparticles based on PNIPAM-g-PEO graft copolymer is generalized on the basis of different model dependent methods. It takes into account the specific features of the experimental procedure and equipment used during the experimental study of the drug release kinetics. The rate parameters are numerically evaluated when fitting each model curve to the available experimental data for indomethacin. Numerical simulation of drug release for 5% and 20% ethanol content is performed and the reliability of the used approach is discussed. It is established that the drug release rate is strongly influenced by the ethanol content. The considered numerical approach enables modeling of different drugs release under the same experimental equipment as well as inclusion of some new model functions describing other mechanisms controlling the release kinetics. | |
Motion Analysis of Chinese Bajiquan Based on Three-dimensional Images of Biomechanics | 189-198 |
Ming Zi [ +/- abstract ][ full text ] | |
With the development of sports biomechanics, human motion mechanical characteristics have received more and more attention from plenty of researchers. Therefore, how to analyze the biomechanics of the living body has become the principle problem at the present stage. In this study, the three-dimensional (3D) image was adopted for a sport dynamics analysis of the riding style of the Chinese Bajiquan. First of all, the change rules of the temporal characteristic parameters when the research objects in the experiment group and the control group completing the riding style action were analyzed based on the characteristics of the action; in the initial stage of the action, the movement speed was relatively slow, and with the center of gravity of the right feet moving down, stable support was formed. Secondly, parameters such as hip joint angle and knee joint angle, etc., were tested from the perspective of dynamics sensors and a rigid block model was constructed to accurately calculate the joint angle. The hip joint guaranteed the stability of center of gravity during movement; the fluctuation of the ankle joint was relatively small, while the maximum fluctuation range of the trunk angle during movement was small, which could keep the upper limbs up straight as well as reduce fluctuation, and the lowering of the center of gravity was good for the stability of the lower limbs. When the riding style action was completed, the toes of the research objects in the experiment group would buckle subconsciously to control the balance of the body. Therefore, the riding style requires the interaction among different parameters, which conforms with the characteristics of the Chinese Bajiquan. | |
Research on Wushu Actions and Techniques Based on a Biomechanical Sensor System | 199-206 |
Xiaohong Wang, Chuan Zhi, Qiang Wang [ +/- abstract ][ full text ] | |
Wushu actions and techniques is an index reflecting the differences in physical quality, basic skills and performance level between athletes. But the gap narrows because of the rapid development of sports events with high difficulty and aesthetic values. Thus, it is urgent to improve Wushu techniques and create new ones. This study measured and quantitatively analyzed Wushu actions and techniques using a biomechanical sensor and biomechanical theory, aiming to provide scientific guidance and technical support for the promotion and improvement of Wushu level and the enhancement of the visual sense and competitiveness of Wushu. In the study, the plantar pressure of a flying kick was measured using a Polyvinylidene Fluoride (PVDF) insole plantar pressure sensor. The data analysis suggested that the heel had little influence on take-off jumping and the load borne by the sole was the largest, which provided a quantitative basis for the innovation and beautification of the take-off action of the jumping kick and also suggested the design of the plantar pressure sensor was reasonable and feasible. | |
Bioecological systems | |
Influence of Temperature and Dissolved Oxygen on Nitrogen and Phosphorus Removal of Integrated Bioreactor | 207-216 |
Chunying Wu, Lixiu Guo [ +/- abstract ][ full text ] | |
An integrated biological membrane sewage treatment device has been designed based on the mechanism of microorganism nitrogen and phosphorus removal and the influence of temperature and dissolved oxygen on nitrogen and phosphorus removal of integrated bioreactor with adoption of this sewage treatment device. The research results shows that the optimal temperature range of microorganism nitrogen and phosphorus removal is 20-30 °C, and the effluent COD removal rate within this range maintains at over 90%; NH4+-N removal rate is between 95% and 97%. TN removal rate is approximately 81%. In practical production, the internal temperature environment of the sewage reactor should be maintained at above 15 °C, to decrease the inhibition of low-temperature environment on growth and reaction speed of nitrobacteria. In various concentrations of DO in the reactor, there is little change in the effluent COD concentration and effluent COD concentration is influenced by temperature. With the increasing of DO concentration, both effluent TN and TP concentrations present changing features of initially decreasing then increasing. The analysis of the influence of comprehensive dissolved oxygen on microorganism nitrogen and phosphorus removal reveals that when the concentration of DO maintains within the range of 1.0-1.5 mg/L, the sewage purification system can attain a higher nitrogen and phosphorus removal effect. | |
Impact of Drought in Serbia on Fire Vulnerability of Forests | 217-226 |
Stanimir Živanović [ +/- abstract ][ full text ] | |
Droughts in Serbia become more and more frequent, and depending on the intensity and duration, they significantly effect on the state of the vegetation and on the creation of conditions for the occurrence of fire. Long periods of drought are typical which increases the fire risk for flammable materials. The majority of dry periods during the year, in this area, occur during the period from June to September. In recent years, drought is has been recorded in October and even in November. This work presents a model that allows the determination of the risk of forest fires affected by drought. The analysis is based on the meteorological data obtained from 26 meteorological stations in Serbia in the period from 1981 to 2010. For evaluation of humidity, Lang’s monthly and yearly rain factor and the Standardized precipitation index (SPI) for the growing period has been used. The aim of this study was to evaluate factors of vulnerability of forests depending on the time of occurrence and duration of the dry season with the assessment of the fire risk degree. There is a correlation between the occurrence of drought and fires in the open air. In Serbia, the danger of forest fires caused by the drought is the greatest in August and July. Particularly affected are the areas where the number of dry days is greater than 20. Some practical data and arguments presented in this paper can be used by the relevant services in assessing vulnerability of forest on fires and implementation of the necessary preventive measures. It is necessary to launch a new scientific researches and to introduce new adaptive forest management in Serbia. The goal of management is to assess the long-term impact of drought and to determine what the community can do now and in the future to respond to these threats. |
Sponsored by National Science Fund of Bulgaria, Grant No DNP 05-40/2016
© 2017, BAS, Institute of Biophysics and Biomedical Engineering