142,647 research outputs found
Alexander Vladimirovich Kuznetsov
Get PDFAlexander Vladimirovich Kuznetsov, also known to the second generation of Soviet logicians as Sasha Kuznetsov, was born in Moscow on the 28 th of October, 1926. He lived a short yet fruitful life and died of cancer 1 in Chişinău, Moldova, on the 24 th of July, 1984
SlideCont: An Auto97 driver for bifurcation analysis of Filippov systems
No full textSLIDECONT, an AUTO97 driver for sliding bifurcation analysis of discontinuous piecewise-smooth autonomous systems, known as Filippov systems, is described in detail. Sliding bifurcations are
those in which some sliding on the discontinuity boundary is critically involved. The software allows for detection and continuation of codimension-1 sliding bifurcations as well as detection of some
codimension-2 singularities, with special attention to planar systems (n = 2). Some bifurcations are also supported for n-dimensional systems. This article gives a brief introduction to Filippov systems, describes the structure of SLIDECONT and all computations supported by SLIDECONT 2.0. Several examples, which are distributed together with the source code of SLIDECONT, are presented
Backlund transformations for many-body systems related to KdV
Get PDFWe present Backlund transformations (BTs) with parameter for certain classical integrable n-body systems, namely the many-body generalised Henon-Heiles, Garnier and Neumann systems. Our construction makes use of the fact that all these systems may be obtained as particular reductions (stationary or restricted flows) of the KdV hierarchy; alternatively they may be considered as examples of the reduced sl(2) Gaudin magnet. The BTs provide exact time-discretizations of the original (continuous) systems, preserving the Lax matrix and hence all integrals of motion, and satisfy the spectrality property with respect to the Backlund parameter
Sobre el buen planteamiento y propagación de regularidad de la ecuación Zakharov-Kuznetsov
Get PDFAbordamos el problema de propagación de regularidad y decaída en la variable x, para las soluciones asociadas al problema de valor inicial (PVI) para la ecuación k-generalizada Zakharov-Kuznetsov bidimensional. Además, se discuten algunas propiedades importantes para este fin, invocando el buen planteamiento en los espacios de Sobolev H^s(R^2) con s s_k, donde s_k es el indice de regularidad en los datos iniciales, que garantizan buen planteamiento al (PVI) de la ecuación (k-gZK), junto con estimaciones de las soluciones que son requeridas. (Texto tomado de la fuente)Abstract. We address the problem of propagation for regularity and decay in the variable x associated with the initial value problem (IVP) of the k -generalized Zakharov-Kuznetsov two-dimensional equation: (k-gZK) ( ∂tu + u kux + ∂x(∆u) = 0 k ∈ Z + , x, y ∈ R , t ≥ 0 u(x, y, 0) = u0(x, y) ∈ H1 + (R 2 ). In addition, for this purpose some important properties are discussed, invoking the well posedness in the Sobolev spaces Hs (R 2 ) with s sk where sk is the regularity index of the initial data in order to ensure well posedness for the (k-gZK) (IVP), along with estimates of the solutions that are required.Maestrí
Overview and Comparison of the Main Approaches to the Implementation of Contact Tracing Mechanisms in the COVID-19 Pandemic
No full textThe spread of the COVID-19 pandemic poses new challenges and threats to the international community. In particular, today the number of people infected with coronavirus infection already exceeds 80 million, almost 2 million died from the pandemic, and these terrible statistics are not final. Under these conditions, quarantine restrictions are almost the only effective means of counteracting the effects of the epidemic by reducing the rate of virus spread. However, quarantine restrictions have extremely serious consequences for the world economy, they have already led to a significant reduction in production and, consequently, jobs in almost all sectors of the economy. Therefore, the development and implementation of the latest information technologies for contact tracking in the context of the COVID-19 pandemic is an extremely important and urgent task. The purpose of this article is to research and substantiate various information technologies (such as Bluetooth, Wi-Fi, GPS, etc.) in contact tracking tools to prevent the spread of infectious diseases. We analyze different approaches to the implementation of contact tracing mechnisms, highlight their advantages and disadvantages as well as opportunities for improvement. Also we analyze examples of real applications of the advanced countries functioning at the state level
Methods of Evaluation and Comparative Research of Cryptographic Conversions
No full textThe security of decentralized systems built on Blockchain technology is directly determined by the efficiency of the applied cryptographic transformations. Classical blockchain technology mainly uses several cryptographic primitives: hash function, electronic signature, encryption, etc. In particular, the hash function is used for several purposes as the generation of an address or user ID; hashing of transactions and blocks to confirm the indisputable block against network errors, as well as the hash value of the previous block is used as a reference in the formation of the next. The use of digital signatures in the blockchain system introduces services for the integrity and integrity of transactions. In turn, in any blockchain system there is a pool of transactions, each of which must be signed. This ensures that the transaction will not be altered, the signature of the transaction ensures that it is signed by a person who can then be identified, and, in fact, the signature can help determine “whether the user has the right to conduct the transaction.” Block ciphers are one of the most common cryptographic primitives, which is also used as a structural element of hash functions, message authentication codes, and so on. Thus, for the operation of monitoring and tracking programs using Blockchain technology, it is necessary to study various cryptographic primitives, in particular, hash functions, electronic signatures, encryption schemes, etc
Design of the Residual Adder of Two Numbers
No full textIt is known that an important and topical scientific and applied problem is the problem of constructing the structure of an adder operating in the residual number system (RNS). Such a non-positional adder for an arbitrary value mi of the RNS modulus is a sequential set of n= log 2 (m i-1)+1] binary one-bit adders (OBA), united by connections, like connections of positional binary adders. The use of additional connections made it possible to create an adder that implements the operation of adding two residues. A set of k adders modulo is an adder of two numbers in RNS. Specific examples of constructing structures of binary adders for various values of the RNS moduli are given
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