Abstract: By using autonomous tuning tools to optimize database systems, a lot of time-consuming, manual work can be automated. However, self-tuning database systems are trying to optimize global metrics of efficiency, they may set back rare, but critical functions of applications that use the database. The priority of application functions cannot be expressed in existing solutions, therefore, another approach may be needed. In this paper, a session-based method is presented, where application functions are represented as sessions, by building and using language models based on previous observations. With this technique, a similarity measure can also be defined, to interpret minor differences between sessions caused by program logic, as similarity. If usage patterns appear on user level as well, it is reasonable to construct user groups along similar behavior, to utilize such patterns. As the most significant part of an autonomous solution is forecasting, a method is also presented to predict future workload characteristics, by identified user groups. Then, this approach has been evaluated in practice, mainly to determine the optimal corpus size and validate session recognition.

Keywords: self-tuning database; autonomous system; dynamic database tuning; response time optimization

Abstract: This paper proposes a model predictive control for a hybrid transformer (HT) with matrix converter (MC). The proposed HT system is composed of a power transformer connected to a power electronic converter which controls the output voltage on the secondary side. The proposed solution of HT is used to resolve power quality issues and power flow control in the electrical power distribution system. The advantages of predictive control are its very simple realization and the possibility to optimize various predefined criteria. Presented in the paperr is a discussion of the conception of a model predictive control strategy to compensate for voltage sags, swells and harmonics on the grid side by providing continuous AC voltage regulation of the HT. Also, presented are the preliminary simulation results, which verify the high performance of the proposed predictive control.

Keywords: Model Predictive Control; Power Transformer; Matrix Converter; Voltage Compensator

Abstract: In this paper, constrained optimal control of a current source rectifier (CSR) is presented, based on a mathematical model developed in Park’s frame. To comply with the system constraints an explicit model-based predictive controller was established. To simplify the control design, and avoid linearization, a disjointed model was utilised due to the significant time constant differences between the AC and DC side dynamics. As a result, active damping was used on the AC side, and explicit Model Predictive Control (MPC) on the DC side, avoiding non-linear dynamics. The results are compared by simulation with the performance of a state feedback control.

Keywords: model predictive control; current source rectifier; space vector modulation; modeling; constrained control

Abstract: This paper presents a comparative study of improvements to the algorithms for license plate extraction from images captured using conventional, modest-quality cameras. It compares the results and efficacy of two similar algorithms which primarily differ in the raw image pre-processing stage of the initial image. One algorithm uses the Gabor filter bank with distinctly crisp parameters; the other relies on the fuzzified Gabor filter bank with fuzzified parameters to facilitate their adjustment. Results indicate that the fuzzy reasoning introduced for Gabor filter parameter adjustment improves the detection of the components of interest in complex images and adds minimal deviation compared to the Gabor filter bank with distinctly crisp parameters.

Keywords: Gabor Filter; Filter Bank; Crisp Parameters; Parameter Fuzzification; License Plate Detection

Abstract: A routing algorithm for wireless sensor networks with a random distribution in a target observation area is proposed. In practice, selecting a path to route data from a source node to a destination node in a sensor network is very useful. An investigation is carried out on the combination of centrality measures and a routing algorithm to determine whether this can improve the route selected by the network’s decision. Various measures of centrality are used and the network’s response is evaluated with regards to the route selected by the network’s decision when some nodes fail. It is demonstrated through simulations that controlling sensor nodes efficiently with a high measure of centrality gives a network the ability to resist node failures or attacks. Furthermore, this provides the network with high failure tolerance. In this paper, a routing algorithm that uses centrality measures to select the shortest path (a low-energy path between the source and destination node) is implemented.

Keywords: Graph Theory; Routing algorithm; Shortest path; low cost; Wireless Sensor Network

Abstract: The relation between the quality of institutions and long term growth is currently an accepted stylized fact, which has good support in empirical literature with regard to both developing and developed countries. In the case of the second group, the quality of intuitions is crucial for keeping their abilities to face quick technological changes, which is a condition for maintaining their international competitiveness. The objective of the article is to analyse the quality of institutions in the European Union countries in the years 2000-2015 from the perspective of its influence on the speed of resources reallocation. The research touches upon the question of the abilities of the countries to take advantage of the knowledge based-economy potential. The concept of the institutional quality is rooted in the transaction costs theory framework. The phenomenon under evaluation is treated as a multiple-criteria problem. Thus, modified TOPSIS method based on entropy measure for objective weighting is applied here. The research shows institutional disparities between Northern and Southern European countries and confirms significant institutional reforms implemented in the Central European economies, which resulted in an improvement of their institutional quality with regard to knowledge-based economy requirements.

Keywords: quality of institutions; European Union; entropy measure; multiple-criteria analisis; TOPSIS

Abstract: The paper covers organisation of pipelined processing of data received from heat stations. New software architecture was developed for processing data received from the heating network. Development of a new analytical information system based on pipeline data processing has allowed increased efficiency of work in heat supply systems. The mechanisms for data storage have been established, as well as work sequence and monitoring of heating networks. This architecture is based on a parallel-pipeline data processing system. The idea of such an approach of data processing was transferred from the system of organization of work of the central processor of a personal computer with processes and streams. A distinctive feature of our system is the ability to work with different databases. It can be adapted to various modern systems of data storage and communication in heating systems. The timely operational monitoring described in the article made it possible to change the modes of operation of heat points and the central heat point in real time, which affects the increase in the reduction of heat consumption. The real reduction made was approximately 9 percent. Hopefully, this allows that with the implementation of this approach at the industrial level heat gain and, respectively, energy will increase even more.

Keywords: pipelined data processing; heat stations; heating networks; database; information system

Abstract: As automated driver assistance functions are getting more and more popular, they will surly have a significant impact on our life especially considering security and the expected serious effects of malicious interventions. In light of the introduced aspects, the Test Field of Zalaegerszeg has started a research to evaluate the required professional and scientific framework to prevent transport systems from malicious external intervention. With regard to this aspect, the homologation system has been analyzed. In accordance with this the main objective of the article is to develop integrity level structure related to transport systems especially focusing on security issues. In this context the paper reconsiders the structure of ASIL to provide a proper framework focusing on the outstandingly important issues of cybersecurity. To develop a novel SIL framework a tailor-made method is identified to define risk parameter values related to certain SIL categories. At the end of the research, the investigation has determined the acceptable hazard rates related to the S&SIL architecture.

Keywords: cybersecurity integrity level; automotive safety integrity level; clustering model; tolerable hazard rate; hazard classification category

Abstract: The problem of energy quality has recently gained much recognition, one of the reasons being, that there is an increasing number of devices which require energy that meets high quality standards. An improvement in this respect, can be achieved by effective management of reactive power flow in the power system. Maintaining balance in active and reactive power is of key importance for the flawless functioning of the power system. This paper discusses theoretical issues underpinning calculations of active, reactive power and of energy loss in MV/LV transformers. Based on the parameters of transformers and data from consumer meters on active and reactive power, active and reactive power and energy loss was obtained, with the view to assess the efficiency of active power and energy transfer through MV/LV transformers.

Keywords: modelling; energy losses; active and reactive energy

Abstract: Herein, we introduce an additional term into the induction equation (one of the Maxwell’s equation). The related Lagrangian formalism applying the scalar and vector potentials is fitted to this modified Maxwell’s equations. In the framework of Hamiltons’s principle we are able to deduce Klein-Gordon equations with negative “mass term” for the field variables electric field E and magnetic induction B. We can conclude from the mathematical structure of the equations that a repulsive interaction appears. The Wheeler propagator can be calculated for the present case by which the time evolution of the field can be discussed. In spite of the situation that these equations have tachyon solutions, the results are in line with the causality principle. As a consequence of the theory, a spontaneous charge disjunction process may rise in the field.

Keywords: Maxwell’s equations; Klein-Gordon equation with negative “mass term”; Lagrangian, Wheeler propagator; charge distribution

Abstract: This article presents an application-oriented method for the structural synthesis of control systems for multichannel linear objects. It provides a general form, based on the compensation for object dynamics and disturbances. The algorithm is based onalgebraic transformations of the mathematical model of the object and reference systems. The general procedure for the synthesis of a control algorithm is presented by the example of a SISO first-order object. Parametric robustness and correspondence of the system behavior to its own reference filters were derived. The possibility of applying this method to control non-linear objects presented in the form of "State Dependent Coefficient (SDC)" is ascertained. A simplified example is given by the synthesis of the motion control of a one-link manipulator with a drive, described by a second-order nonlinear equation. Control of a two-link manipulator represented by its linearized equation is demonstrated. The convenience of the proposed synthesis method for controlling multi-channel objects under certain simplifications allowed by the specifics of the use of objects is shown. The numerical example shows the independence of the system through individual channels, a zero static error in all the modes of operation and the correspondence of the system behavior to given dynamics.

Keywords: robot manipulator; control algorithm; multi-dimensional control system; reverse model; reference filter; structural synthesis

Abstract: Manufacturing and service providing companies perform or make others perform logistics tasks. This area is of great importance in everyday operations, and managers do their best in choosing operations and processes. Appropriate logistics processes and decisions mostly determine the companies’ successful operation, profitability, profit-making ability, and their costs. However, an important step before defining them is missing in most cases, namely getting to know the processes to execute, and the best method for that purpose is to get a preliminary simulation of the processes. The goal of the study is to highlight the advantages of modeling, what unnecessary introductory processes and financial losses can be avoided through simulation, and underline how deeper knowledge we can get with the help of this method.

Keywords: Lean; simulation; SME; logistics processes; loss sources

Abstract: A new parametric probability distribution function is introduced and its connections with some well-known distribution functions are discussed. Due to its flexibility, we call the novel distribution function the pliant distribution function. We show that the asymptotic pliant probability distribution function can coincide with the Weibull-, exponential and logistic probability distribution functions. Furthermore, we demonstrate that with appropriate parameter settings, the novel distribution gives a simple and accurate approximation to the standard normal probability distribution. Next, we show that the pliant probability distribution function, as an alternative to the Weibull- and exponential distribution functions, can be used to model constant, monotonic and bathtub-shaped hazard functions in reliability theory. We also point out that a function transformed from the new probability distribution function can be applied in the so-called kappa regression analysis method, which may be viewed as an alternative to logistic regression.

Keywords: pliant distribution; Weibull distribution; logistic distribution; normal distribution; approximations