Abstract The quantitative analysis of the blood flow in the brain tissue is one of the important problems in neurosurgery. It arises when diagnosing acute ischemic stroke. This problem can be solved using computed tomography (CT) perfusion imaging. There are various methods for extracting quantitative characteristics of cerebral blood flow from CT perfusion data, which differ in degrees of their noise

Abstract Visualization of large dynamic scenes is a challenging computer graphics problem. There are many approaches to solving this problem: frustum culling, occlusion culling, geometry simplification, and rendering optimization. One of the effective methods is the levels of detail (LOD) for scene objects. For large scenes, the hierarchical LOD (HLOD), whereby the levels of detail are created for

Abstract The creation of visualization component for onboard civil aviation systems is considered. The software used on board must comply with the internationally accepted safety standards. This imposes additional requirements for both the hardware used and the system development process. This paper is devoted to the use of multicore processors in avionics embedded systems for improving the performance

Abstract This paper investigates the effectiveness of the DVM/DVMH technology as applied to the parallel solution of parametric problems in gas dynamics. The solution of these problems is based on the construction of a generalized computational experiment, which involves multiple solutions of the problem with the variation of its key parameters. This approach is efficient only when using parallel technologies

Abstract This paper is dedicated to the analysis of the existing approaches to video codecs comparisons. It includes the revealed drawbacks of popular comparison methods and proposes new techniques. The performed analysis of user-generated videos collection showed that two of the most popular open video collections from media.xiph.org which are widely used for video-codecs analysis and development

Abstract This paper presents a CAD model simplification procedure that consists in recognizing and suppressing blend chains of certain types. The proposed method involves Euler operators (KEV, KEF, and KFMV) developed on top of an open-source geometric modeling kernel. The simplification process consists of two stages: recognition and suppression. The suppression stage ensures the geometric and topological

Abstract This paper describes a new method for medical data segmentation based on superpixel propagation. The proposed method is a modification of the classical region growing algorithm and partly inherits the concept of octrees. The key difference of the proposed approach is the transition to the superpixel domain, as well as more flexible conditions for adding neighbor superpixels to the region.

Abstract This paper considers the task of real-time visualization of detailed 3D scalar fields through isosurfaces (surfaces representing constant values of scalar fields). A new method is proposed to overcome the limitations associated with the intensive reading of dummy (non-visualized) vertices from video memory and overheads of their storage, which arise when implementing isosurface polygonization

Abstract One of the main problems of mixed reality devices is the lack of universal methods and algorithms for the visualization of virtual world objects in real space. The key point of natural perception of virtual objects in the real world is the creation of natural lighting conditions for virtual world objects by light sources located in the real world, i.e. the formation of natural glares on virtual

Abstract In this paper, we discuss the possibility of using computer algebra tools in the process of modeling and qualitative analysis of mechanical systems and problems from theoretical physics. We describe some constructions—Courant algebroids and Dirac structures—from the so-called generalized geometry. They prove to be a convenient language for studying the internal structure of the differential

Abstract In this paper, we describe an algorithm for constructing an analogue of the Binet formula, which is essential in deriving a functional relation to the classical Riemann zeta-function. The algorithm is implemented in the Maple computer algebra system. An example that illustrates the operation of the algorithm is presented.

Abstract Linear ordinary differential equations whose coefficients are infinite (formal) power series given in a truncated form are considered. Computer algebra procedures (implemented in Maple) for constructing solutions of two forms are suggested. The procedures find the greatest number of series terms occurring in the solutions that can be found for the given truncated series—coefficients.

Abstract Recently, it has been shown constructively how a finite set of hypergeometric products, multibasic hypergeometric products or their mixed versions can be modeled properly in the setting of formal difference rings. Here special emphasis is put on robust constructions: whenever further products have to be considered, one can reuse –up to some mild modifications – the already existing difference

Abstract In this paper, we describe design principles for certified programs of fraction arithmetic over any domain with the greatest common divisor (GCD) function. This is a small part of the DoCon-A library of certified programs, which is designed by the author of this paper. In this system, programs include definitions of the corresponding mathematical notions and proofs for the main properties

Abstract An autonomous Hamiltonian system with two degrees of freedom that is invariant under the Klein four-group of linear canonical automorphisms of the extended phase space of the system is studied. A sequence of symplectic transformations of the monodromy matrix of the symmetric periodic solution of this system is constructed. Using these transformations, the structure and bifurcation of the phase

Abstract Computer algebra systems are complex software systems that cover a wide range of scientific and practical problems. However, the absolute coverage cannot be achieved. Often, it is required to create a user extension for an existing computer algebra system. In this case, the extensibility of the system should be taken into account. In this paper, we consider a technology for extending the SymPy

Abstract For the work with polynomials such data representations as lists of terms, geobuckets, and heaps are usually used. In this paper, an attempt to give a new look on the representation of polynomials for computing involutive and Gröbner bases of systems of nonlinear polynomial equations is made. The proposed approach makes it possible to execute a part of this computational task on the GPU, which

Abstract The problem of finding a periodic motion of generalized Atwood’s machine in which the pulley of a finite radius is replaced by two small pulleys and one of the objects may oscillate in the vertical plane is discussed. Using symbolic computations, the equations of motion are derived and their periodic solutions in the form of power series in a small parameter in the case of small oscillations

Abstract First, the normal form in the vicinity of the stationary solution of the autonomous Hamiltonian system is recalled. Next, linear periodic Hamiltonian systems are considered. For them, normal forms of the Hamiltonians in the complex and real cases are found. A feature of the real case in the situation of parametric resonance is discovered. Next, normal forms of Hamiltonians of nonlinear periodic

Abstract For industrial logistics tasks, an algorithm for clustering a given set of machine parts on the basis of engineering drawings is proposed. To speed up clustering, the values of each parameter are fuzzified and local maximums of the N-dimensional histogram are sought. The search uses the selection of adjacent vectors based on the recalculation of coordinates from the N-dimensional space to

Abstract The main ideas of the development of the software implementation of an algorithm for the fast automatic classification of seismic signals based on diagnostic patterns are described. The process of adaptation and integration of this implementation into the distributed computations system Apache Spark is described in detail. A software solution for the preliminary processing of the signals and

Abstract This paper investigates some specific features of continuous user identification based on hidden monitoring of keystroke dynamics when creating a free text. Our analysis of static identification approaches does not reveal any significant limitations on their application to continuous identification. The main feature of continuous identification is the method for collecting dynamic information

Abstract This paper presents results of a research in the field of software development, design methods, as well as training and synthesis of binary neural networks. The research is based on the model of a biomorphic neuron proposed by A.A. Zhdanov, which features noise immunity and is capable of forgetting and additional training. Software tools for designing and visualizing the modeling of binary

Abstract A modified approach to recovering the trajectories of dynamic objects in a scene from stereo images is proposed. This approach is based on the use of an extended point representation of objects, visual odometry, and a novel set of algorithms. Object identification algorithms and the block diagram of the step-by-step data processing are described. Results of numerical experiments for synthetic

Abstract In this paper, we present an intermediate representation (IR) language for the concise and generalized description of type system specification features in dynamically typed programming languages. The intermediate representation is based on pattern matching and features type-level computation. It is inspired by the intermediate representation “Assembly language” for Refal-2. In contrast to

Abstract Cloud computing is one of the most prominent parallel and distributed computing paradigm. It is used for providing solution to a huge number of scientific and business applications. Large scale scientific applications which are structured as scientific workflows are evaluated through cloud computing. Scientific workflows are data-intensive applications, as a single scientific workflow may

Abstract Early warning during sky survey provides a crucial opportunity to detect low-mass, free-floating planets. In particular, to search short-timescale microlensing (ML) events from high-cadence and wide- field survey in real time, a hybrid method which combines ARIMA (Autoregressive Integrated Moving Average) with LSTM (Long-Short Time Memory) and GRU (Gated Recurrent Unit) recurrent neural networks

Abstract Nowadays artificial intelligence and swarm robotics become wide spread and take their approach in civil tasks. The main purpose of the article is to show the influence of common knowledge about surroundings sharing in the robotic group navigation problem by implementing the data transferring within the group. Methodology provided in article reviews a set of tasks implementation of which improves

Abstract It is intuitively clear that search for scientific publications often has many characteristics of exploratory search. The purpose of this paper is to formalize this intuitive understanding, explore which scientific search tasks can be classified as research search ones, what general approaches to the research search problem exist, and how they are implemented in specialized search engines