Business Continuity Options for Oracle Technology Solutions

One of the most important aspects which information technology deployments must fulfill are business continuity requirements. In a highly competitive market, business users of information technology are aware that even a slight downtime of their application will result in financial loss and even some potential customers. A second reason is that the information stored in their databases is very important for running their business so they cannot afford to lose it due to some unexpected hardware failure or a disaster. The Oracle Corporation, as one of the biggest providers of information technology solutions, offers various options that can address business continuity requirements ranging from high availability up to disaster recovery. In our article we will describe various technological solutions offered by Oracle to address even the most complex business continuity requirements. This will include clustering technologies, standby databases and site guard among others. Of course, those solutions are rather expensive so business users must be realistic in defining their business continuity requirements to avoid overspending for their implementation

Epitaxial growth of metal oxide thin films on semiconductors

Epitaxy represents a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined crystallographic orientations with respect to the seed layer. The epitaxy is usually implemented in the cases when new functionality is to be integrated with the already present platform. The two methods for the epitaxial growth of thin films i.e. pulsed laser deposition (PLD) and ion beam assisted deposition (IBAD) will be compared. We will highlight the most important aspects of the epitaxial growth of metal oxides (MO) on semiconductor (SC) substrates, including processes in the vapor phase and at the MO/SC interface. We will describe how the growth parameters (temperature, partial pressure, deposition rate, etc.) can affect the stoichiometry, morphology and overall crystalline structure and properties of the MO thin film. The important properties of MO and MO/SC interface will be also highlighted from the point of view of photoelectrochemical water splitting. Beside the growth parameters, the role of ion beam irradiation in tuning of physical and chemical properties of the MO and SC will be also discussed. The selection of appropriate characterization methods (surface and bulk) will be also highlighted for monitoring the growth of MO and the processes relevant in photoelectrochemical water splitting. An outline of the first experiments to be performed will be also presented.Twentieth Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 30 – December 2, 2022, Belgrade, Serbi

TWO-DIMENSIONAL GMM-BASED CLUSTERING IN THE PRESENCE OF QUANTIZATION NOISE

In this paper, unlike to the commonly considered clustering, wherein data attributes are accurately presented, it is researched how successful clustering can be performed when data attributes are represented with smaller accuracy, i.e. by using the small number of bits. In particular, the effect of data attributes quantization on the two-dimensional two-component Gaussian mixture model (GMM)-based clustering by using expectation–maximization (EM) algorithm is analyzed. An independent quantization of data attributes by using uniform quantizers with the support limits adjusted to the minimal and maximal attribute values is assumed. The analysis makes it possible to determine the number of bits for data presentation that provides the accurate clustering. These findings can be useful in clustering wherein before being grouped the data have to be represented with a finite small number of bits due to their transmission through the bandwidth-limited channel.

THE USAGE OF LAMBERT W FUNCTION FOR IDENTIFICATION AND SPEED CONTROL OF A DC MOTOR

The paper proposes a new method of identifying the linear model of a DC motor. The parameter estimation is based on the closed-loop step response of the DC motor under a proportional controller. For the application of the method, a deliberate delay of the measured speed was introduced. The paper considers the speed regulation of the direct current motor with negligible inductance by applying 1-DOF and 2-DOF, proportional integral retarded controllers. The proportional and integral gain of the PI retarded controllers was received by using a pole placement method on the identified model. The Lambert W function was applied for the identification and in designing the controller with the purpose of finding the rightmost poles of the closed-loop as well as the boundary conditions for selecting the gain of the PI controller. The robustness of the calculated controllers was considered under the effect of an disturbance, uncertainty in each of the DC motor parameters as well as perturbations in time delay

CURRENT TRENDS AND CHALLENGES IN DISTRIBUTED CONTROL SYSTEMS – AN OVERVIEW

In this paper, innovations in the field of distributed control systems have been considered. Without any claim for completeness, a short summary on current trends in this area has been provided. A special attention is paid to application of blockchain technologies in distributed control systems, game theoretical approach for distributed control applications, and advantages of distributed control for power systems. Also, one of the main issues of modern distributed control systems – cybersecurity has been considered

Solvothermaly synthesized copper doped bismuth vanadate

Photoeletrochemical (PEC) water splitting is a promising method for clean energy production and different oxide materials have been explored to find the right solution. Among them, as one of the most promising photoanode materials, bismuth vanadate (BiVO4) has attracted a lot of attention due to the suitable band gap edge alignment, lowcost synthesis method and great visible light harvesting features. Nowdays, research related to the BiVO4 is mostly oriented towards repairing poor charge transfer properties which exist due to the high rate of electron–hole recombination. Metal doping is one of the strategies to improve these intrinsic drawbacks. Herein, we report physicochemical properties of solvothermaly sinthesized pristine BiVO4, 1%-, 2.5%- and 5%- Cu-doped BiVO4 powders at 180 ºC for 8 h. X-ray diffraction (XRD) study indicates that, depending on the degree of doping, material exists in monoclinic or tetragonal scheelite phase. Pure monoclinic phase was formed in a case of pristine, 1%- and 2.5%- Cu doped samples. After doping with 5 %, phase transition occurred and material showed tetragonal phase. Scanning electron microscopy (SEM) reveals that samples with monoclinic phase consists of worm-like and prismatic structures while tetragonal samples exhibited spherical shape. Furthermore, structure was examined with Raman and FTIR spectroscopy. The results were in accordance with diffraction study where band positions were well matched with phase composition. Optical properties were characterized with UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. Monoclinic samples showed band gap around 2.4 eV, while sample with tetragonal phase has band gap around 2.8 eV. PL showed that that monoclinic samples possess better recombination features than tetragonal ones. Photoelectrochemical measurements suggest that material is sensitive towards visible light and, after doping, improved its performance towards oxygen evolution reaction.8th Conference of Young Chemists of Serbia; 29th October, Belgrade, Serbi

Fuzzy practical exponential tracking of an electrohydraulic servosystem

Cilj ovog rada je da doprinese teorijskoj i praktičnoj primeni fazi logičkog upravljanja korišćenjem koncepta praktičnog praćenja. Predlaže se novi fazi upravljački algoritam za ostvarivanje željenog kvaliteta praćenja jednog elektrohidrauličkog pozicionog servosistema, koji se može naći u mnogim industrijskim uređajima. Fazi logički kontroler je jedan od najjednostavnijih. On koristi samo jednu ulaznu veličinu, sa linearnom metodom zaključivanja. Fazi prateći algoritam upravljanja je zasnovan na principu samoprilagodljivosti. Strukturna karakteristika takvog sistema upravljanja je postojanje dve povratne sprege: globalne, negativne po izlaznoj veličini i lokalne, pozitivne po upravljačkoj veličini. Takva struktura obezbeđuje sintezu upravljanja bez poznavanja unutrašnje dinamike objekta i bez merenja poremećajnih veličina. Predloženi fazi prateći algoritam upravljanja obezbeđuje promenu greške izlazne veličine po unapred definisanom eksponencijalnom zakonu. Prezentuju se rezultati simulacije nelinearnog matematičkog modela hidrauličkog servosistema.The aim of this paper is to contribute to the theoretical and practical applications of fuzzy logic control using practical tracking concept. A new fuzzy control algorithm is proposed to achieve the desired tracking performance of a nonlinear electrohydraulic position servo system, which can be found in many manufacturing devices. The fuzzy logic controller is one of the simplest. It employs only one input, with linear fuzzy inference method. The practical tracking control algorithm is based on the selfadjustment principle. The structural characteristic of such a control system is the existence of two feedback sources: the global negative of the output value and the local positive of the control value. Such a structure ensures the synthesis of the control without the internal dynamics knowledge and without measurements of disturbance values. The proposed fuzzy practical control algorithm ensures the change of the output error value according to a prespecified exponential law. The simulation results of the nonlinear mathematical model of the hydraulic servo system are presented

Discrete-time exponentially stabilizing fuzzy sliding mode control via lyapunov's method

The exponentially stabilizing state feedback control algorithm is developed by Lyapunov's second method leading to the variable structure system with chattering free sliding modes. Linear time-invariant discrete-time second order plant is considered and the control law is obtained by using a simple fuzzy controller. The analytical structure of the proposed controller is derived and used to prove exponential stability of sliding subspace. Essentially, the control algorithm drives the system from an arbitrary initial state to a prescribed so-called sliding subspace S, in finite time and with prescribed velocity estimate. Inside the sliding subspace S, the system is switched to the sliding mode regime and stays in it forever. The proposed algorithm is tested on the real system in practice, DC servo motor, and simulation and experimental results are given

Fuzzy practical exponential tracking of an electrohydraulic servosystem

Cilj ovog rada je da doprinese teorijskoj i praktičnoj primeni fazi logičkog upravljanja korišćenjem koncepta praktičnog praćenja. Predlaže se novi fazi upravljački algoritam za ostvarivanje željenog kvaliteta praćenja jednog elektrohidrauličkog pozicionog servosistema, koji se može naći u mnogim industrijskim uređajima. Fazi logički kontroler je jedan od najjednostavnijih. On koristi samo jednu ulaznu veličinu, sa linearnom metodom zaključivanja. Fazi prateći algoritam upravljanja je zasnovan na principu samoprilagodljivosti. Strukturna karakteristika takvog sistema upravljanja je postojanje dve povratne sprege: globalne, negativne po izlaznoj veličini i lokalne, pozitivne po upravljačkoj veličini. Takva struktura obezbeđuje sintezu upravljanja bez poznavanja unutrašnje dinamike objekta i bez merenja poremećajnih veličina. Predloženi fazi prateći algoritam upravljanja obezbeđuje promenu greške izlazne veličine po unapred definisanom eksponencijalnom zakonu. Prezentuju se rezultati simulacije nelinearnog matematičkog modela hidrauličkog servosistema.The aim of this paper is to contribute to the theoretical and practical applications of fuzzy logic control using practical tracking concept. A new fuzzy control algorithm is proposed to achieve the desired tracking performance of a nonlinear electrohydraulic position servo system, which can be found in many manufacturing devices. The fuzzy logic controller is one of the simplest. It employs only one input, with linear fuzzy inference method. The practical tracking control algorithm is based on the selfadjustment principle. The structural characteristic of such a control system is the existence of two feedback sources: the global negative of the output value and the local positive of the control value. Such a structure ensures the synthesis of the control without the internal dynamics knowledge and without measurements of disturbance values. The proposed fuzzy practical control algorithm ensures the change of the output error value according to a prespecified exponential law. The simulation results of the nonlinear mathematical model of the hydraulic servo system are presented

Primena MCNP5/X softvera i voksel fantoma za računanje doza jonizujućeg zračenja u organima čovečijeg tela

Predmet istraživanja ove doktorske disertacije je primena voksel geometrije za računanje apsorbovanih doza jonizujućih zračenja u organima ljudskog tela u različitim situacijama ozračivanja. Cilj rada i zadaci Cilj ove disertacije je poboljšanje dozimetrije jonizujućih zračenja primenom „voksel“ modela. Zadaci koji su postavljeni pred autora ove doktorske disertacije sastoje se u sledećem: Kreiranje voksel modela na osnovu CT ili MR snimaka konkretnih osoba prema kome je ljudski organizam predstavljen kao skup malih zapreminskih elemenata tkiva - tzv voksela; Implementacija voksel modela u već postojeći model ljudskog tela – ORNL fantom prema kome su organi predstavljeni kao geometrijska tela preko jednačina analitičke geometrije u 3D; Primena i implementacija voksel geometrije u MCNP5/X softveru; Proračun doza jonizujućih zračenja u zapreminama od interesa u vokselizovanoj geometriji; Primena voksel geometrije i na druge modele fantoma i njihova primena u različitim situacijama. Metodologija U ovom radu primenjeno je više metoda: a) Obradom DICOM slika dobijenih na osnovu CT snimka konkretnih osoba pomoću softvera ImageJ. b) Kreiranje voksel modela datih osoba iz ImageJ identifikovanjem pojedinih organa; v) Razvoj ulaznih fajlova za MCNP5/X na osnovu prethodnih tačaka Zoran Jovanović: Primena MCNP5/X softvera i voksel fantoma za računanje doza jonizujućih zračenja u organima čovečjeg tela -doktorska disertacija 2 g) Primena MCNP5/X za računanje apsorbovanih doza u raznim situacijama izlaganja jonizujućim zračenjima. Rezultati Izračunate su apsorbovane doze u sledećim slučajevima ozračivanja u nuklearnoj medicini i radiologiji: - primena BNC terapije; - doze koje primaju operater i pacijent u intravenskoj radiologiji; - doze pri primeni radiofarmaceutika 133Xe, 99mTc i 81mKr i - proračun doza koje prima očno sočivo. Zaključak Vokselizacija omogućuje bolji uvid u raspodelu apsorbovanih doza po pojedinim organima i tkivima, što inače nije moguće pri primeni ORNL modela. Moguće je identifikovati „vruće tačke“ u telu u slučaju akcidenta i sl.SUMMARY The subject of the research of this doctoral dissertation is the application of the voxel geometry for calculation of the absorbed doses of ionizing radiation in the organs of the human body in different irradiation situations. The goal of work and tasks The aim of this dissertation is to improve the dosimetry of ionizing radiation using the "voxel" model. The tasks set before the author of this doctoral dissertation consist of the following: • Creation of a voxel model based on CT or MR images of specific persons by which the human organism is presented as a set of small volume elements of the tissue, so-called voxel; • Implementation of the voxel model in the already existing model of the human body - ORNL phantom according to which the bodies are presented as geometric bodies through the equation of analytical geometry in 3D; • Application and implementation of voxel geometry in MCNP5/X software; • Calculation of the dose of ionizing radiation in volumes of interest in voxelized geometry; • Application of geometry according to other phantom models and their application in different situations. Methodology In this paper several methods have been applied: a) By processing DICOM images obtained on the basis of a CT image of specific individuals using ImageJ software; b) Creation of a model of a given model of a given model by the identification of individual organs; v) Development of input files for MCNP5 / X based on the previous points; Зоран Јовановић: Примена MCNP5/X софтвера и воксел фантома за рачунање доза јонизујућих зрачења у органима човечјег тела -докторска дисертација 167 g) Application of MCNP5 / X for calculating the absorbed doses in various situations of exposure to ionizing radiation. Results Absorbed doses were calculated in the following cases of irradiation in nuclear medicine and radiology: - application of BNC therapy; - doses received by the operator and patient in intravenous radiology; - doses in the application of radiopharmaceutical 133Xe, 99mTc and 81mKr and - the calculation of a dose that receives eye lens. Conclusion Voxelization provides a better insight into the distribution of absorbed doses by individual organs and tissues, which is not otherwise possible with the use of the ORNL model. It is possible to identify "hot spots" in the body in the event of an accident, etc