## achievements and applicationsM. Gospodinov, E. Gospodinova. Mathematical Analysis of the Linear and Non-linear Properties of Electrocardiological Data

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.

## achievements and applicationsP. Lebamovski, E. Petkov. Studying Stereometry in Secondary Schools Using 3D Technologies

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.

## achievements and applicationsG. Georgieva-Tsaneva, M. Gospodinov, E. Gospodinova. Analysis of Heart Rate Variability through Statistical Parameters

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.

## achievements and applicationsR. Hrischev. Internal Control System for the Main Raw Materials for the Paper Production from Recycled Materials

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.

## achievements and applicationsV. Dimitrov, L. Popov. Identification of Significant Movement Parameters of Trains Powered by Electric Locomotive Series 45

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.

## achievements and applicationsD. Hristov, G. Georgiev, A. Stoyanova-Doycheva. Academic Pubication System

Key Words: Virtual Physical Space; digital library; institutional repository; publication system.

Abstract. This article describes and analyzes the problems and tasks associated with the storage and processing of data in the Virtual Physical Space (ViPS), a scientific project of the University of Plovdiv Paisii Hilendarski. Existing storage platforms, in particular DSpace – an institutional repository application, and the possibilities of their application are being explored, not only as a publication tool, but also in a way that allows the integration of a digital library in ViPS and its interaction with the other components of the virtual space. A functional intelligent Web-based academic publication system is presented, created by implementing DSpace REST API, a programmatic interface to DSpace communities, collections, items, and bitstreams and by using the BDI (belief-desire-intention) software model for its agent part.

## achievements and applicationsD. Nikolov, M. Lazarova. Metaheuristics for Optimization in Resource Planning and Business Process Management

Key Words: Enterprise resource planning; business process management; optimization; job shop scheduling; metaheuristics; machine learning.

Abstract. The paper presents a metaheuristics based framework for resource planning optimization and business project management. Possibilities for utilization of metaheuristic algorithms are presented in view of solving job shop scheduling problem for resource planning in ERP. A general framework for resource planning and business process management is suggested that utilizes several metaheuristics approaches. The proposed framework allows integration in ERP based on development of an optimization agent in multiagent framework.

## achievements and applicationsR. Draganov, K. Haralampiev, P. Ruskov. Blockchain Service Control Platform in Smart Hotel

Key Words: Innovation; tourism; smart enterprise; blockchain; JEL Classification: Z32.

Abstract. Smart blockchain services control platform in the smart hotel is applied to enable optimal control of the services provided in the tourist enterprises by reducing the cost of business transactions and increase the trust among participants in the process, by using intelligent devices and equipment, the Internet of Things (IoT), and blockchains. The paper is focused on a useful model for IoT-enabled telematic devices in a smart hotel via a blockchain-based smart contract. At the tourist site, smart sensors and devices are mounted on the various devices and technological blocks in an intelligent platform providing an efficient economy for tourist services. The purpose of the utility model is based on the principle of the intelligent blockchain system for the implementation of secure and certified provision and payments of services in a tourist complex, without relying on a third party, trusted or not, through the introduction of blockchain platform for the execution of the service and payment.