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Of all publications in the section: 4 008
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Working paper
Иванова А. С., Gasnikov A., Pasechnyuk D. et al. Optimization and Control. Working papers by Cornell University., 2019
In this paper, we present a generic framework that allows accelerating almost arbitrary non-accelerated deterministic and randomized algorithms for smooth convex optimization problems. The main approach of our envelope is the same as in Catalyst (Lin et al., 2015): an accelerated proximal outer gradient method, which is used as an envelope for a non-accelerated inner method for the ℓ2 regularized auxiliary problem. Our algorithm has two key differences: 1) easily verifiable stopping criteria for inner algorithm; 2) the regularization parameter can be tunned along the way. As a result, the main contribution of our work is a new framework that applies to adaptive inner algorithms: Steepest Descent, Adaptive Coordinate Descent, Alternating Minimization. Moreover, in the non-adaptive case, our approach allows obtaining Catalyst without a logarithmic factor, which appears in the standard Catalyst (Lin et al., 2015, 2018).
Added: Oct 11, 2020
Working paper
Ivanova A., Стонякин Ф., Пасечнюк Д. et al. Optimization and Control. Working papers by Cornell University., 2019
Network utility maximization is the most important problem in network traffic management. Given the growth of modern communication networks, we consider the utility maximization problem in a network with a large number of connections (links) that are used by a huge number of users. To solve this problem an adaptive mirror descent algorithm for many constraints is proposed. The key feature of the algorithm is that it has a dimension-free convergence rate. The convergence of the proposed scheme is proved theoretically. The theoretical analysis is verified with numerical simulations. We compare the algorithm with another approach, using the ellipsoid method (EM) for the dual problem. Numerical experiments showed that the performance of the proposed algorithm against EM is significantly better in large networks and when very high solution accuracy is not required. Our approach can be used in many network design paradigms, in particular, in software-defined networks.
Added: Oct 25, 2020
Working paper
Lyashevskaya O., Vlasova E., Litvintseva K. et al. Linguistics. WP BRP. НИУ ВШЭ, 2018. No. 77.
A data analysis tool of the Corpus of Russian Poetry (a part of the Russian National Corpus) is designed for quantitative research in various areas of versology and linguistics aspects of poetic texts. The core part, a statistic database of the corpus, includes annotation at the level of texts, verses, words as well as patterns of words, letters and stress. The tool allows a user to study certain properties (e. g. rhyming patterns, lexical co-occurrence) taken alone and in their interaction, both in the whole corpus and in subcorpora. Besides that, it facilitates contrastive studies of two chosen subcorpora and a few case studies demonstrating applicable methods and potential for further research in the field of the Digital literary studies.
Added: Dec 13, 2018
Working paper
Piperski A., Grabovskaya M., Gridneva E. et al. Linguistics. WP BRP. НИУ ВШЭ, 2019. No. 92.
In Russian, there are many ways to address a person by name. For instance, a man called Aleksandr may be addressed as Aleksandr, Aleksandr Ivanovič, Saša, Sašen′ka, Saška, Sanja, etc. This study aims at analyzing the use of various strategies of naming the listener throughout the last two centuries. It uses the data from the Russian National Corpus to establish the direction of change in address patterns and combines a statistical approach with a manual inspection of selected examples.
Added: Dec 15, 2019
Working paper
Карась А., Pyle W., Schoors K. Институциональные проблемы российской экономики. WP1. НИУ ВШЭ, 2012. No. 03.
The empirical literature assessing the connection between land rights, access to  finance and investment activity has focused largely on actors that, for multiple reasons, might face difficulties accessing credit. Communities of small-scale farmers or poor urban households in developing countries, that is, may not be the best place to look for evidence as to whether more secure land rights are sufficient to facilitate borrowing by providing borrowers with a collateralizable asset. We explore this relationship in a setting in which fi  nancial market frictions are apt to be less severe – i.e., among large, urban, industrial enterprises. Exploiting policy-induced variation across Russian regions, we use recently-collected survey data to show that private rights to land do indeed facilitate access to external financing and promote investment. This finding is supplemented by additional survey evidence that points to private land serving as an important source of collateral.
Added: Dec 15, 2012
Working paper
M.V. Karasev. arxiv.org. math. Cornell University, 2014. No. 1404.1790v2.
For slow–fast quantum systems, we compute first corrections to the quantum action and to the effective slow Hamiltonian.
Added: Apr 9, 2014
Working paper
Alexander Zlotnik, Ilya Zlotnik. Working papers by Cornell University. Cornell University, 2016. No. 1609.07758.
We present direct logarithmically optimal in theory and fast in practice algorithms to implement the tensor product high order finite element method on multi-dimensional rectangular parallelepipeds for solving PDEs of the Poisson kind. They are based on the well-known Fourier approaches. The key new points are the fast direct and inverse FFT-based algorithms for expansion in eigenvectors of the 1D eigenvalue problems for the high order FEM. The algorithms can further be used for numerous applications, in particular, to implement the tensor product high order finite element methods for various time-dependent PDEs. Results of numerical experiments in 2D and 3D cases are presented.
Added: Sep 29, 2016
Working paper
Zasimova L. S., Shishkin S. Public Administration. PA. Высшая школа экономики, 2013. No. WP BRP 07/PA/2013.
The adoption of new medical technologies in Russian public hospitals is an important part of healthcare modernization and thus is a subject for public finance and regulation. Here we examine the decision-making process on adoption of new technologies in Russian hospitals, and the institutional environment in which they are made. We find that public hospitals operate within a strategic-institutional model of decision making and tend to adopt technologies that bring indirect benefits to their heads/physicians. Unlike Western clinics, the interests of Russian hospital heads and physicians are driven by the possibilities to obtain income from a part of hospital activities: the provision of chargeable medical services to the population, as well as receiving informal payments from patients. The specifically Russian feature of the decision-making process is that hospitals are strongly dependent on health authorities’ decisions about new equipment acquisition. The inefficiency problems arise from the contradiction between hospitals’ and authorities’ financial motivation for acquiring new technologies: hospitals tend to adopt technologies that bring benefits to their heads/physicians and minimize maintenance and servicing costs, while authorities’ main concern is initial cost of technology. The main reason for inefficiency of medical technology adoption arises from centralization of procurement of medical equipment for hospitals that creates the preconditions for rent-seeking behaviour of persons making such decisions.
Added: Dec 30, 2013
Working paper
Caroleo F. E., Coppola G., Semerikova E. V. Annals of CRISEI 2018. ISBN: 978-88-98279-07-4. University of Naples Parthenope, 2018
The aim of this work is to apply a statistical method to measure regional gaps both in terms of structural disparities (sectoral, productive or labor supply composition) and labor market performance (participation rate and unemployment). To this end, a multivariate analysis method was applied that, starting from the main economic indicators of the Russia, allows estimating the factors that measure structural diversity in regional labor markets, as well as their dynamics over time. In this way it is possible to test the existence of processes of convergence between regions, or the formation of clusters of regions between them progressively divergent.
Added: Jul 10, 2019
Working paper
Rusinova V. Basic research program. WP BRP. National Research University Higher School of Economics, 2019. No. 87.
This article concentrates on two recent judgments issued by the European Court of Human Rights (ECHR) Chambers, on Centrum för Rättvisa v. Sweden and Big Brother Watch and Others v. the United Kingdom, which expressly acknowledged that mass surveillance per se does not violate the Convention on the Protection of Human Rights and Fundamental Freedoms. These judgments have been recently referred to the Grand Chamber, thus giving hope that the approach taken in respect of the launch of mass interception of communications and metadata has a chance to be revisited.  The author reveals whether this approach follows from the jurisprudence of the ECHR, how plausible the argumentation of this court is and how legalization for the bulk interception of data relates to the stance taken by the ECJ, which until that time was dealing with questions of the protection of the right to respect for private life and personal data using the general paths initially paved by the ECHR. The article discloses what precise content in terms of the protection of right to respect for private life lies behind the main findings on the compatibility of bulk interception per se with the Convention on the Protection of Human Rights and Fundamental Freedoms, namely, in which part this court has refused to examine the measures undertaken by states in compliance with Article 8 and in which parts it has strengthened (or relaxed) already inferred criteria. Finally, taking into account the current position of the ECHR at this crossroads, the article dwells on causes that influenced the decisions of its Chambers.
Added: Apr 1, 2019
Working paper
Galkin S., Rybakov S. math. arxive. Cornell University, 2019. No. 14379.
For a family of K3 surfaces we implement a variation of a general construction of towers of algebraic curves over finite fields given in a previous paper. As a result we get a good tower over k=𝔽_{p^2}, that is optimal if p=3.
Added: Nov 6, 2019
Working paper
Vereshchagin N. arxiv.org. math. Cornell University, 2020
We consider tilings of the plane by two prototiles which are right triangles. They are called the small and the large tiles. The small tile is similar to the large tile with some similarity coefficient ψ. The large tile can be cut into two pieces so that one piece is a small tile and the other one is similar to the small tile with the same similarity coefficient ψ. Using this cut we define in a standard way the substitution scheme, in which the large tile is replaced by a large and a small tile and the small tile is replaced by a large tile. To every substitution of this kind, there corresponds a family of the so-called substitution tilings of the plane in the sense of [C. Goodman-Strauss, Matching Rules and Substitution Tilings, Annals of Mathematics 147 (1998) 181-223]. All tilings in this family are non-periodic. It was shown in the paper [N. Vereshchagin. Aperiodic Tilings by Right Triangles. In: Proc. of DCFS 2014, LNCS vol. 8614 (2014) 29--41] that this family of substitution tilings is not an SFT. This means that looking at a given tiling trough a bounded window, we cannot determine whether that tiling belongs to the family or not, however large the size of the window is. In the present paper, we prove that this family of substitution tilings is sofic. This means that we can color the prototiles ina finite number of colors and define some local rules for colored prototiles so that the following holds. For any tiling from the family, we can color its tiles so that the resulting tiling (by colored tiles) satisfies local rules. And conversely, for any tiling of the plane satisfying the local rules, by removing colors we obtain a tiling from the family. Besides, the considered substitution can be generalized to colored tiles so that the family of substitution tilings for the resulting substitution coincides with the family of tilings satisfying our local rules.
Added: Jul 24, 2020
Working paper
Prokhorov Y., Zaidenberg M. math. arxive. Cornell University, 2020
We show that the affine cones over any Fano--Mukai fourfold of genus 10 are flexible; in particular, the automorphism group of such a cone acts highly transitively outside the vertex. Furthermore, any Fano--Mukai fourfold of genus 10, with one exception, admits a covering by open charts isomorphic to the affine four-space.
Added: Aug 19, 2020
Working paper
Ivan Cheltsov, Park J., Won J. arxiv.org. math. Cornell University, 2013
We show that affine cones over smooth cubic surfaces do not admit non-trivial $\mathbb{G}_a$ -actions.
Added: Dec 27, 2013
Working paper
Busjatskaja I., Kochetkov Y. arxiv.org. math. Cornell University, 2016. No. 1607.05325.
A non-degenerate two-dimentional linear operator Ф  transforms the unit circle into ellipse.We define the coefficient of deformation k(Ф), as the relation of the lendth of the smaller ellipses axis to its bigger one. In this work we compute the mean value of k(Ф).Analogously, we define the deformation coefficient  k(Ф) in three-dimensional case and give an estimation of its mean value.
Added: Jun 28, 2017
Working paper
Busjatskaja I., Kochetkov Y. math. arxive. Cornell University, 2016. No. 1603.02938.
In this work we demonstrate, how the use of polar decomposition allows one to  understand metric proporties of non-degenerate linear operators on the plane. We study how the non-isometric operatpr changes the length of vectors and the angles between the vectors.
Added: Mar 10, 2016
Working paper
Chistyakov Vyacheslav V. arxiv.org. math. Cornell University, 2011. No. 1112.5561v1.
The notion of a (metric) modular on an arbitrary set and the corresponding modular space, more general than a metric space, were introduced and studied recently by the author [V.V. Chistyakov, Metric modulars and their application, Dokl. Math. 73 (1) (2006) 32–35, and Modular metric spaces, I: Basic concepts, Nonlinear Anal. 72 (1) (2010) 1–14]. In this paper we establish a fixed point theorem for contractive maps in modular spaces. It is related to contracting rather “generalized average velocities” than metric distances, and the successive approximations of fixed points converge to the fixed points in a weaker sense as compared to the metric convergence.
Added: Feb 6, 2013
Working paper
Kozyrin A. N. Law. LAW. Высшая школа экономики, 2018. No. 81.
Added: Apr 10, 2018
Working paper
Takeyama A., Constantinou N., Vinogradov D. IMES Discussion Paper Series. Institute for Monetary and Economic Studies, Bank of Japan, 2012. No. 2012-E-14.
This paper develops a framework to estimate the probability of default (PD) implied in listed stock options. The underlying option pricing model measures PD as the intensity of a jump diffusion process, in which the underlying stock price jumps to zero at default. We adopt a two-stage calibration algorithm to obtain the precise estimator of PD. In the calibration procedure, we improve the fitness of the option pricing model via the implementation of the time inhomogeneous term structure model in the option pricing model. Since the term structure model perfectly fits the actual term structure, we resolve the estimation bias caused by the poor fitness of the time homogeneous term structure model. It is demonstrated that the PD estimator from listed stock options can provide meaningful insights on the pricing of credit derivatives like credit default swap.
Added: Jun 27, 2018
Working paper
Piskunova N. African Horn: Security Challenged. 111. The Edwin Mellen Press, 2014
This monograph  reviews key challenges to security in the region of North-East Africa, specifically in the area of the African Horn region. The issues discussed in this book, include the problems of soft security in this region, namely the problem of democratic transitions and hybrid regimes, terrorism and radicalization of muslim organizations, foreign policy issues and conflict between Ethiopia and Eritrea in 1998-2000, issue of state failure in Somalia and other related issues.
Added: May 6, 2014
Working paper
Kazun A. D., Kazun A. Political Science. PS. Высшая школа экономики, 2017. No. WP BRP 51/PS/2017.
Donald Trump and his team have often been accused of having close ties to Russia and Russians expressed much greater support for Trump than residents of other countries. This article provides the first systematic analysis of Russian media coverage of Trump's activities during and after the election campaign. It concludes, on the basis of a sentiment analysis of relevant articles and network agendas of 500 Russian magazines and 250 leading federal newspapers, that Trump's media portrayal was not necessarily positive. During the election, Trump was portrayed by the Russian media not as Russia's favorite candidate, but as Hillary Clinton's opponent and a critic of U.S. recent policies. Only for a short period after Trump's victory in the elections, did the Russian media represent him as a friend of Russia, since there was hope that the new president would lift political and economic sanctions. Trump's policies failed to meet the expectations of the Russian people, and from the beginning of 2017, media coverage of Trump has become critical, hopes for lifting of political sanctions have weakened, and public opinion about the U.S. president has turned negative.
Added: Nov 13, 2017