Numerical modeling of wave processes in layered media in the Arctic region

The aim of this work is the numerical simulation of wave propagation in media with linear-elastic and acoustic layers as exemplified by the seismic prospecting problems in the Arctic region and the explosive impact on an iceberg. The complete system of equations describing the state of a linearly elastic body and the system of equations describing the acoustic field are solved. The grid-characteristic method is used to provide the contact and boundary conditions, including the contact condition between acoustic and linear-elastic layers, to be correctly described.     

Analysis of instantaneous cardiac rhythm in a model of multifractal dynamics based on Holter monitoring

For the specific analysis of the variability of RR intervals of the cardiac rhythm, a method for measuring the instantaneous cardiac rhythm (ICR) represented by a multifractal dynamical model (MDM) has been developed. The advantages of this method, compared to the statistical methods of analysis of the RR intervals used, have been demonstrated. The method allows possible catastrophes of the cardiovascular system to be predicted. Using the data of Holter monitoring and the program system developed, we have plotted ICR curves, an ICR piecewise linear trend, and variability charts for three randomly chosen time intervals. The self-similarity (fractality) of the ICR up to an accuracy of 5% has been shown based on the explicit data. The MDM parameters have been calculated based on the ICR data. The analysis of the dynamics of these parameters has been conducted and their compliance with the status of the patient examined has been studied. The relevance of the ICR examination within MDM is closely related to the necessity of recognizing new markers of adverse cardiovascular episodes. The research performed shows that the results obtained could be taken as a basis for developing a new mathematical method of ICR examination based on Holter monitoring.     

Efficiency of classical molecular dynamics algorithms on supercomputers

High performance computing hardware is developed faster than the algorithms for fundamental mathematical models such as classical molecular dynamics are adapted. A wide variety of choice makes it necessary to determine clear criteria based on the computational efficiency of a specific algorithm on a particular hardware. The LINPACK benchmark can no longer serve this purpose. In this paper, we analyze the solution time–peak performance metric based on practical considerations. In this metric, we compare different hardware (both current and obsolete) based on the example of the LAMMPS benchmark, which is widely used for atomistic simulations. It is shown that the considered metric can be used for unambiguous comparison of different combinations of CPUs, accelerators, and interconnection.     

On fractional faces of the metric polytope

The integrality recognition problem is considered on a sequence M _{n, k} of nested relaxations of a Boolean quadric polytope, including the rooted semimetric M _n and metric M _{n, 3} polytopes. The constraints of the metric polytope cut off all faces of the rooted semimetric polytope that contain only fractional vertices. This makes it possible to solve the integrality recognition problem on M _n in polynomial time. To solve the integrality recognition problem on the metric polytope, we consider the possibility of cutting off all fractional faces of M _{n, 3} by a certain relaxation M _{n, k} . The coordinates of points of the metric polytope are represented in homogeneous form as a three-dimensional block matrix. We show that in studying the question of cutting off the fractional faces of the metric polytope, it is sufficient to consider only constraints in the form of triangle inequalities.     

Construction and verification of PLC-programs by LTL-specification

An approach to construction and verification of PLC-programs for discrete problems is proposed. For the specification of program behavior we use the linear-time temporal logic LTL. Programming is carried out in the ST-language according to an LTL-specification. The correctness analysis of an LTL-specification is carried out by the symbolic model checking tool Cadence SMV. A new approach to programming and verification of PLC-programs is shown by an example. For a discrete problem we give a ST-program, its LTL-specification and an SMV-model. The purpose of the article is to describe an approach to programming PLC, which would provide the possibility of PLC-program correctness analysis by the model checking method. Under the proposed approach the change of the value of each program variable is described by a pair of LTL-formulas. The first LTL-formula describes situations that increase the value of the corresponding variable, the second LTL-formula specifies conditions leading to a decrease of the variable value. The LTL-formulas (used for specification of the corresponding variable behavior) are constructive in the sense that they construct the PLC-program, which satisfies temporal properties expressed by these formulas. Thus, the programming of PLC is reduced to the construction of LTL-specification of the behavior of each program variable. In addition, an SMV-model of a PLC-program is constructed according to LTL-specification. Then, the SMV-model is analysed by the symbolic model checking tool Cadence SMV.     

Universal national security platform for distributed information and telecommunication systems

The problem of information security in distributed information and telecommunication systems has been considered. The paper analyzes the sources of threats in such systems. Existing security mechanisms have been examined. The class of threats associated with the use of untrusted (including imported) equipment is considered separately. The architecture of a universal security platform for distributed information and communication systems has been proposed.     

Analytical review of methods of providing internet anonymity

The Internet community all over the world is showing growing interest in a subject of information security and anonymity on the Internet, especially after revelations of Edward Snowden, when it became known about mass spying by certain organizations (such as the US National Security Agency) on Internet users, companies, political organizations, etc. This led to the active development of various anonymous networks, VPN services, proxies, etc. The aim of this article is to review popular methods of providing Internet anonymity, compare them, and discover their benefits and disadvantages.     

Approach to the construction of the generalized functional-semantic cyber security model

In this paper, the functional-semantic model of cyber security is proposed as an initial step towards the development of a new unified methodological cyber security basis. This model makes it possible to formalize requirements for confidentiality, integrity, and availability, as well as to obtain ontological knowledge inferences about the system security state.     

Move blocking strategy applied to re-entrant manufacturing line scheduling

Model predictive control (MPC)-based approach to fab-wide scheduling has been suggested to solve constraint-aware production optimization and in-process inventory level control simultaneously at each scheduling instance. However, application of this approach to real fab suffers from computational difficulties brought by the need to solve a huge optimization problem on-line as real fab scheduling problems are characterized by long cycle times, multiple product types, hundreds of machines/processing steps and re-entrant product flows. This study explores the use of an offset-blocking strategy combined with a modified recursive least square (RLS) estimation in the fab-wide scheduler, in order to alleviate the difficulty. The strategy is tested on a modified version of published case study called Intel Mini-Fab (IMF) problem. Despite its simplicity, the blocking strategy showed excellent performance in the face of realistic demand changes and plant/model mismatch.     

Generating a Visual Language of Performance-Driven Configurations for the Principal Façade of a Prototype Sustainable House

A performance-driven application of shape grammars is presented. A parametric shape grammar that generates a language of pattern designs for the principal façade of a prototype house—featuring a 5 × 20 matrix of electrochromic windows—based equally on performance and aesthetic criteria is described. The adjustment of the chromatism and light transmittance of each individual windowpane on the façade enables the adjustment of solar radiation at the house interior. The novel aspect of the grammar is that it encodes performance constraints of interior daylight illuminance and associates them to visual, symmetry principles of two-dimensional pattern generation. Twelve parametric rules account for the generation of the façade pattern language and five subclasses account for the symmetry of the patterns in the language.