DOI: 10.7256/2306-4196.2014.6.13302

Abstract: Traditionally, in pulsed NMR spectroscopy signals are registered by subtracting from it the reference frequency which is near to the Larmor frequency of the nucleus, followed by digitization and further processing. In modern NMR apparatus the receiving channel consists of preselector, quadrature detector, normalizing amplifier, low pass filter and analog-to-digital converter. The disadvantage of such a receiver is the length of the analog section, since each module adds additional noises. Thermal noise occurs on fluctuations of electrons in conductors having a particular temperature. Such fluctuations have spectral components that are in the same frequency band with useful signals.  This article analyzes the nature of the noise of the receiving channel of nuclear magnetic resonance relaxometer and evaluates its characteristics. Authors suggest replacement of the analog part of receiving channel with the digital quadrature detector and theoretically calculate the benefit from the exclusion of several noise sources.

DOI: 10.7256/2306-4196.2014.6.13306

Abstract: The article presents a comparison of computational complexity of two logical classification algorithms: an algorithm of sequential search (brute force) and algorithm of inductive states prediction. Logic algorithms are implemented in Matlab. For comparison of the computational complexity of classification algorithms author uses Zakrevskiy technique. Classification problem is one of the main problems in detection of threats of cyber attacks in the information system. Information about the signs of cyber attacks detection can be received from various sources (sensors) of software and hardware of the information system, for example, antivirus tools, dumps RAM logs, hard drives, user logon information, etc. Each of those sources contain information that can be used to determine the presence of an attack on the system. The article reviews the problem of logical classification of already existing data using two algorithms: an algorithm of sequential search (brute force) and algorithm of inductive states prediction. The use of the adapted method of inductive states prediction allowed to reduce amount of computation and get the average gain K ≈ 9,3 and thereby reduce time of detection of computer attacks.

DOI: 10.7256/2306-4196.2014.6.13642

Abstract: Modern systems of computer vision use intelligent algorithms that solve a wide class of problems from simple text recognition to complex systems of spatial orientation. One of the main problems for developers of such systems is in selection of unique attributes which remain invariant to various kinds of transformations. The article presents a comparative analysis of methods of detection and spatial localization of groups of point objects. The reviewed methods are compared by the performance and efficiency at specified dimensions. As of today there are no universal approaches to determine of such attributes, and its’ selection depends on the context of the problem being solved and on the registered conditions of observation. Various kinds of descriptors such as points, lines, angles and geometric primitives can be selected as dominating attributes. The authors study  algorithms for detection of groups of point objects based on the minimum spanning tree (MST) and using a model of associated continuous image (ACI).

DOI: 10.7256/2306-4196.2014.6.13297

Abstract: When controlling the wheeled vehicle there’s always a need in the forced changing of its trajectory, ie in a steering system the operation of which is based on that steering angle changes through steering mechanism (using external force). That requires a kinematic connection between a steering mechanism and steering drive and thus leads to increase of complexity of machine design. In this regard, the question arises: is it possible to avoid this complication? It turns out that it is possible with usage of steering system based on the difference between the rotational speeds of the steered wheels. The article describes a method of controlling a wheeled vehicle by setting a certain speed of rotation of the steered wheels without using the steering mechanism. The author describes and algorithm for controlling of vehicle based on a proposed method. For the inventive method in the form as it is described in the appended claims the possibility of its implementation using the methods described in the application and means known before the priority date is confirmed.  Therefore, the claimed invention meets the condition of "industrial applicability". Thus, it is possible to control rotation of the vehicle wheels using the chosen law providing the conditions necessary for a rotation motion taking into account the surface irregularities.

DOI: 10.7256/2306-4196.2014.6.13477

Abstract: One of the leading trends in the development of education in today's world is the creation of a system for comprehensive evaluation of the quality of education. The approaches to defining the quality of education are being actively developed, different aspects, indicators and parameters are being studied. Complex estimation the effectiveness of educational organizations is a multicriteria task that requires establishing the criteria and procedures for their evaluation for solving. The article analyzes the methods of multi-criteria optimization which may become components of a comprehensive assessment of the quality of educational activities. The author analyzes methods of multicriteria optimization and theory of neural networks. The article reviews multicriteria statistical models for a comprehensive evaluation of the quality of educational organizations. One of them is based on the educational qualimetry and involves the use of methods of convolution dominant and compensated indicators into an integrated indicator. Another model involves the use of neural networks and is based on the analytical data processing technology. With the implementation of the models considered such important quality indicators of a comprehensive assessment of the effectiveness of the quality of educational institutions as objectivity of evaluation, scalability, simplicity and ease of use, may increase. The results obtained can be widely used in a comprehensive assessment of the quality of educational institutions at various education levels.

DOI: 10.7256/2306-4196.2014.6.13483

Abstract: The author reviews a problem of use of educational computational experiments in the study of physical phenomena. By educational computational experiment author means experiment on the mathematical model of the object carried out with the aid of a computer for the purpose of learning. A set of simplified versions of educational computational experiments adapted to the conditions of learning form a System of educational computational experiments. The article analyzes the examples of the use of educational computer experiment for: 1) for the study of the magnetization of a ferromagnet, calculation of the magnetization curve and hysteresis loop; 2) study of chaotic oscillations of a Dafing pendulum, occurrence of bifurcation in changes in the profile of the potential well, study of Poincaré section and the evolution of the phase volume. The authors apply mathematical and computational methods (simulation) modeling, which involves the construction of a mathematical model and building a software simulating the phenomenon under study based on the numerical solution of the corresponding to its’ system of equations. The novelty of the work is in the proposed four simple computer programs in Pascal, allowing: 1) obtain the magnetization curve and hysteresis loop for a ferromagnet in a changing magnetic field; 2) simulate the oscillation of the Dafing pendulum; 3) study the transition of oscillator into the chaotic regime at a change of the potential well; 4) get a Poincaré section and to study the evolution of the phase volume for Dafing pendulum.