Етикет: приложения

Key Words: HRV; ECG; linear analysis; non-linear analysis; Poincaré plot.

Abstract. The article is devoted to the mathematical analysis of the linear and nonlinear properties of heart rate variability (HRV) determined by digital electrocardiological data. The advantage of the mathematical methods used is their ability to detect minor cardiovascular abnormalities and a way to evaluate the overall functional capabilities of the body. The quantitative dimensions of the studied parameters when using linear mathematical methods of analysis have significant clinical application because the boundaries of norm-pathology are known. The application of non-linear mathematical methods in data analysis provides additional information on the physiological status of patients. The article presents the results of the linear analysis of the studied data in the frequency domain and the results of the nonlinear analysis by applying the Poincare graphical method, which allows the doctors to see the whole electrocardiological record at a glance and quickly detect cardiovascular disorders if there are some. The analysis of HRV by applying linear and nonlinear methods provides ample opportunity for clinical and research applications.

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Key Words: 3D modeling; dynamic software; research approach; stereometry.

Abstract.  The article presents a new approach to the training of students in Stereometry in the secondary schools. The aim is to create an application that presents the learning material of the textbooks in a way that is easily understood by learners while at the same time excites them and motivates them for new knowledge. Graphics are presented which can be implemented in two ways: solid and wireframe (transparent), their advantages and disadvantages are considered. An analysis of 3D modeling techniques such as LOD (Level of Details), voxels and sweep representation is also done. The study highlights the advantage of the system, which is the stereoscopic perspective. Its implementation is realized by a system without immersion or projector. The constructivism and the connectivism are considered as suitable methodologies in case of application-based training in mathematics.

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Key Words: Heart Rate Variability; Statistical Analysis; Atrial Fibrillation; Premature Ventricular Contraction; Normal Sinus Rhythm; Orthogonal Transforms.

Abstract. Cardiovascular diseases are among the first causes of death. The main cardiovascular diseases are myocardial ischemia, various types of arrhythmias, reduced ability to contract the left ventricle. Cardiac testing is performed non-invasively by electrocardiograph or Holter monitoring. The paper examines, through the application of orthogonal transforms, the continuous holter recordings of individuals with Atrial Fibrillation, Premature Ventricular Contraction and Normal Sinus Rhythm. The mathematical analysis is performed in the time domain. The results show characteristic differences between patients with both types of arrhythmias and in healthy individuals. The presented  results can be of benefit to cardiology practice in Bulgaria and worldwide.

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Key Words: Internal control; paper; recycling paper.

Abstract. The article introduces effective Internal Control System for the main raw materials for the production of paper from recycled materials for packaging industry. In the article are present logical structure and technical realization of the system.

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Key Words: Moment of inertia; resistance force; braking factor; running qualities.

Abstract. In the railway transport practice it is important to maintain sustain control of speed mass, resistance and braking capability of the railway composition. The mass control issue is of great importance especially when in case of transportation of liquid on rail as the liquid leakage will instantly be established using mass control. The resistance control during motion is also a priority as thus we will be able to establish the moment of derailment due to resistance increase. It is important to control the braking capability of the train composition as it enables the engine driver to receive continuous information and if problem in the braking system occurs to take the appropriate action.

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