Razvoj nove klase ortogonalnih filtara s primenom u modeliranju, analizi i sintezi sistema za diferencijalnu impulsno kodnu modulaciju

This PhD dissertation deals with development of new classes of orthogonal filters based on symmetric transformation of their poles to zeroes and vice versa. The filters based on reciprocal transformation are developed and the generalized Malmquist filters orthogonal with respect to a special inner product are designed in this way. The orthogonal filters by using bilinear transformation, including several classes of classical orthogonal cascade filters (Legendre, Laguerre, Müntz-Legendre, Malmquist), are also designed. These filters are practically realized both in analogue and digital techniques. The main quality of these filters is a possibility of adaptive adjustment of filter parameters, i.e. parameters of bilinear transformation, achieving the best filter performances. The final result of this part of research is a wide range of applications of these filters in identification, modelling, analysis, and design of technical systems. The analogue versions of filters are applied in modelling of the system for rubber strip cooling in tyre industry, and their digital versions in modelling of telecommunication system for differential pulse code modulation (DPCM system). It is verified that the models obtained by using these new filters are of higher quality than the models based on classical filters. The other part of research in PhD dissertation refers to the mentioned DPCM system. A complete analysis of DPCM system with arbitrary order predictor is performed for the first time. This relates to the consideration of stability by classical approach, as well as to stochastic stability analysis. The analysis of robust stability by using Kharitonov method is also performed for both deterministic and stochastic case, as well as for low- and high orders of predictors. The parametric sensitivity related to different order-predictors coefficients is also analyzed

IMPLEMENTATION AND TESTING OF WEBSOCKET PROTOCOL IN ESP32 BASED IOT SYSTEMS

This paper gives insight on the WebSocket communication methodin Internet of Things system, where the hardware part of the system is based on ESP32 microcontroller. Method of implementation is discussed and the reliability of the real-time data transfer in Wi-Fi networks is tested and compared with the long-polling method. Special circuit is designed with the goal to stress the hardware part of the system and the client-server communication link in order to enable proper comparison of data transfer methods. For the comprehensive testing of the real-time data ow, a web server application is designed and used to visualize received data. Impact of RSSI on transfer methods is discussed as well. Eciency of the WebSocket method is discussed and then compared to the long-polling method

PROBABILITY OF STABILITY ESTIMATION OF DPCM SYSTEM WITH THE FIRST ORDER PREDICTOR

The probability of stability of DPCM system with the first order predictor is considered in this paper. The basis of the analysis is predictor stability (probability of stability) which is the most important and sufficient condition for stability of the whole system. Influence of predictor stability on system performances (such as signal-to-noise ratio) is considered for concrete signal

NEW CLASS OF DIGITAL MALMQUIST-TYPE ORTHOGONAL FILTERS BASED ON THE GENERALIZED INNER PRODUCT; APPLICATION TO THE MODELING DPCM SYSTEM

A new class of cascade digital orthogonal filters of the Malmquist type based on bilinear transformation for mapping poles to zeroes and vice versa is presented in this paper. In a way, it is a generalization of the majority of the classical orthogonal filters and some newly designed filters as well. These filters are orthogonal with respect to the generalized inner product which is actually a generalization of the classical inner product. Outputs of these filters are obtained by using polynomials orthogonal with respect to the new inner product. The main quality of these filters is that they are parametric adaptive. The filter with six sections is practically realized in the Laboratory for Modeling, Simulation and Control Systems. Performances of the designed filter are proved on modeling and identification of the system for differential pulse code modulation. Real response and response from the proposed filter are compared with regard to the chosen criteria function. Also, a comparative analysis of the proposed filter with some existing filters is performed

DATA COLLECTION TOOL FOR PROCESS IDENTIFICATION USING PLC AND KEPWARE TOOLS

In this paper, we are using the Kepware tools as a data collection tool to collecting data for identifying the process and making the mathematical models is described in this paper. The connection to the process was made using a programmable logic controller like a real time DAQ (Data Acquisition Board and System) device, database and a client application developed for these purposes. Special attention is paid to the possibility of collecting a large amount of process data as the same moment time of data sampling

THE WINDER DANCER POSITION CONTROL MODEL USING DIFFERENT PID CONTROL STRUCTURES AND MICROLOGIX PLC

In the cable industry, improper regulation of the winding speed of the conductor cable, i.e. the position of the tensioner (dancer) leads to improper stretching of the conductor, which significantly affects the characteristics of the final product. Winding speed control is directly related to tensioning which is an additional problem. This paper presents a system for control a cable winding device using a linear PID controller with and without control signal limitation. The system parameters were determined using integral time-weighted absolute error (ITAE) criteria and realized using a conventional PLC controller

THE ROLE OF OLED DEVICES IN THE DEVELOPMENT OF SMART CITIES

In the course of the last few years, interest in the development of smart cities and progress of smart buildings has increased significantly. This development has been significantly increased due to the development of new technologies, innovative functional materials, electronic components and other products. At the same time, it is imperative to use those products that contribute to the preservation of the environment, and above all to energy saving. Thus, new technologies are becoming increasingly attractive, such as the one based on OLED (Organic Light Emitting Diode) technology, which is used in the production of mobile phones, tablet computers, other devices, as well as light sources. Although this technology has been generally known for more than half a century, commercial application of OLED components was not possible due to insufficient efficiency of products based on it. However, the continuous improvement of characteristics and efficiency enabled their more significant application in the past few years. The aim of this work is to provide adequate information about the possibilities of applying some innovative technologies in the planning and development of smart cities. Especially, becoming more familiar with the basic properties and application possibilities of OLED devices can lead to the life quality improvements of city spaces users

DIGITAL MODEL PREDICTIVE CONTROL OF THE THREE TANK SYSTEM BASED ON LAGUERRE FUNCTIONS

The application of the model predictive control (MPC) based on discrete-time Laguerre functions is presented in this paper. A nonlinear three-tank hydraulic system is used as an object to which the proposed algorithm is applied. The paper also presents the method of For the verification of the proposed control method, digital simulations are performed using Matlab.linearization of the nonlinear system, as well as the procedure for the controller design

CONTROL SYSTEM OF STEEL BATTERY CHARGER

A practical realization of control of a diode–thyristor bridge is provided in this paper. The proposed control logic is applied to an NiCd accumulator charger. These accumulators are used for power supply of electrical devices and equipment in CFR locomotives. The control system provides a regular mode of NiCd accumulators charging and discharging, and, in this way, their long lifespan. A hardware configuration and a control algorithm for efficient NiCd accumulator charging and preventing overcharging and overheating are provided

CYTOKINE PROFILE IN RENAL TRANSPLANT PATIENTS IN A LONG-TERM PERIOD AFTER SURGERY

In the long-term period after kidney transplantation, a certain level of tissue inflammation and therefore the production of proinflammatory cytokines, including TNF-α, IL-1β, IL-18 and IL-2 can be found. The aim of our study was to determine the concentrations of TNF-α, IL-1β, IL-18, IL-2 and its soluble receptor (IL-2R) in renal transplant patients, regarding the length of the postoperative period. The study involved 65 patients, transplanted at least 12 months prior to our investigation, divided into three groups, regarding the time passed since the transplantation (12-24, 24-48, and >48 months consecutively). Concentrations of the cytokines in the plasma of the subjects were measured using ELISA method. Group I showed significantly higher concentrations of IL-1b compared to the III (p<0.05), IL-18 compared to the II and III (p<0.05) and TNF-a compared to the II (p<0.05). Cytokine concentrations correlated with the time passed since the transplantation (p<0.05), except for TNF-a. Interleukin-2 correlated negatively with IL-18 and immunosuppressant dosage (p<0.05). Interleukin-1b, IL-18 and TNF-α measurements should be considered for monitoring and detecting potentially subclinical allograft damage in the second year after surgery. However, the dynamics of the change of cytokine concentration may also have been altered by the components of the immunosuppressive protocols used, such as tacrolimus, which is a link that is yet to be examined