Showing papers by "National Research University – Higher School of Economics published in 2012"

Monopolistic Competition: Beyond the Constant Elasticity of Substitution

Abstract: We propose a model of monopolistic competition with additive preferences and variable marginal costs. Using the concept of “relative love for variety,” we provide a full characterization of the free-entry equilibrium.When the relative love for variety increases with individual consumption, the market generates pro-competitive effects. When it decreases, the market mimics anti-competitive behavior. The constant elasticity of substitution is the only case in which all competitive effects are washed out. We also show that our results hold true when the economy involves several sectors, firms are heterogeneous, and preferences are given by the quadratic utility and the translog.

An SEM Approach to Continuous Time Modeling of Panel Data: Relating Authoritarianism and Anomia

Abstract: Panel studies, in which the same subjects are repeatedly observed at multiple time points, are among the most popular longitudinal designs in psychology. Meanwhile, there exists a wide range of different methods to analyze such data, with autoregressive and cross-lagged models being 2 of the most well known representatives. Unfortunately, in these models time is only considered implicitly, making it difficult to account for unequally spaced measurement occasions or to compare parameter estimates across studies that are based on different time intervals. Stochastic differential equations offer a solution to this problem by relating the discrete time model to its underlying model in continuous time. It is the goal of the present article to introduce this approach to a broader psychological audience. A step-by-step review of the relationship between discrete and continuous time modeling is provided, and we demonstrate how continuous time parameters can be obtained via structural equation modeling. An empirical example on the relationship between authoritarianism and anomia is used to illustrate the approach.

Subnational Appointments in Authoritarian Regimes: Evidence from Russian Gubernatorial Appointments

Abstract: Elections are among the most important and least understood institutions in contemporary authoritarian regimes. Theoretically, electoral authoritarian regimes should have an informational advantage that makes them more robust than other types of authoritarian regimes, but much empirical evidence suggests otherwise. In this article we offer a new perspective on why this might be the case. Specifically, we consider how authoritarian elections influence a ruler’s choices in making cadre appointments. We argue that the imperative of winning authoritarian elections forces authoritarian leaders to prioritize the appointment of politically loyal cadres, who can help the regime win elections. This choice often comes at the expense of appointing officials who are competent at making good public policy and promoting economic development, factors that may contribute to long-term regime stability. We test this theory using an original dataset of gubernatorial appointments in one leading contemporary authoritarian reg...

The Monge-Kantorovich problem: achievements, connections, and perspectives

Abstract: This article gives a survey of recent research related to the Monge-Kantorovich problem. Principle results are presented on the existence of solutions and their properties both in the Monge optimal transportation problem and the Kantorovich optimal plan problem, along with results on the connections between both problems and the cases when they are equivalent. Diverse applications of these problems in non-linear analysis, probability theory, and differential geometry are discussed. Bibliography: 196 titles.

Mass appraisal of residential apartments: An application of Random forest for valuation and a CART-based approach for model diagnostics

Abstract: To the best knowledge of authors, the use of Random forest as a potential technique for residential estate mass appraisal has been attempted for the first time. In the empirical study using data on residential apartments the method performed better than such techniques as CHAID, CART, KNN, multiple regression analysis, Artificial Neural Networks (MLP and RBF) and Boosted Trees. An approach for automatic detection of segments where a model significantly underperforms and for detecting segments with systematically under- or overestimated prediction is introduced. This segmentational approach is applicable to various expert systems including, but not limited to, those used for the mass appraisal.

Are indigenous approaches to achieving influence in business organizations distinctive? A comparative study of guanxi, wasta, jeitinho, svyazi and pulling strings

Abstract: Managers in five nations rated scenarios exemplifying indigenous forms of informal influence whose cultural origins were concealed. Locally generated scenarios illustrated episodes of guanxi, wasta, jeitinho, svyazi and pulling strings. Local scenarios were judged representative of local influence processes but so too were some scenarios derived from other contexts. Furthermore, many scenarios were rated as more typical in non-local contexts. While these influence processes are found to be widely disseminated, they occur more frequently in contexts characterized by high self-enhancement values, low self-transcendence values and high endorsement of business corruptibility. Implications for a fuller understanding of local business practices are discussed. © 2012 Copyright Taylor and Francis Group, LLC.

Political Machines at Work: Voter Mobilization and Electoral Subversion in the Workplace

Abstract: We explore how modern autocrats win elections by inducing employers to mobilize their employees to vote for the regime and thereby subvert the electoral process. Using two original surveys of employers and workers conducted around the 2011 parliamentary elections in Russia, we find that just under one quarter of employers engaged in some form of political mobilization. We then develop a simple framework for identifying which firms engage in voter mobilization and which workers are targeted for mobilization. We find that large, financially dependent firms in sectors characterized by asset immobility or slack labor markets whose managers are “core” supporters of the regime can offer their votes to the regime at the lowest cost and therefore are especially likely to mobilize their workers. By identifying the conditions under which workplace mobilization occurs in authoritarian regimes, we contribute to the longstanding debate about the economic bases of democratization (Moore 1966, Boix 2003, Acemoglu and Robinson 2006; Ziblatt 2008; 2009; Mares and Zhu forthcoming). In addition, we explore an understudied means of subverting elections in contemporary autocracies: the use of economic coercion to mobilize voters (Hyde 2006; Myagkov and Ordeshook 2009; Beber and Scacco 2012). Moreover, our research finds that clientelist exchange can thrive in the absence of deeply embedded political parties when it is brokered by employers (Stokes 2005; Nichter 2008).

Quantum Algebraic Approach to Refined Topological Vertex

Abstract: We establish the equivalence between the refined topological vertex of Iqbal-Kozcaz-Vafa and a certain representation theory of the quantum algebra of type W 1+∞ introduced by Miki. Our construction involves trivalent intertwining operators Φ and Φ* associated with triples of the bosonic Fock modules. Resembling the topological vertex, a triple of vectors ∈ $$ {\mathbb{Z}^2} $$ is attached to each intertwining operator, which satisfy the Calabi-Yau and smoothness conditions. It is shown that certain matrix elements of Φ and Φ* give the refined topological vertex C λμν (t, q) of Iqbal-Kozcaz-Vafa. With another choice of basis, we recover the refined topological vertex C λμ ν (q, t) of Awata-Kanno. The gluing factors appears correctly when we consider any compositions of Φ and Φ*. The spectral parameters attached to Fock spaces play the role of the Kahler parameters.

Integrability of Hurwitz partition functions

Abstract: Partition functions often become ?-functions of integrable hierarchies, if they are considered dependent on infinite sets of parameters called time variables. The Hurwitz partition functions Z = ?Rd2 ? kR?R(t(1))??R(t(k))exp?(?n?nCR(n)) depend on two types of such time variables, t and ?. KP/Toda integrability in t requires that k ? 2 and also that CR(n) are selected in a rather special way, in particular the naive cut-and-join operators are not allowed for n > 2. Integrability in ? further restricts the choice of CR(n), forbidding, for example, the free cumulants. It also requires that k ? 1. The quasi-classical integrability (the WDVV equations) is naturally present in ? variables, but also requires a careful definition of the generating function.

Clustering: A Data Recovery Approach

Abstract: What Is Clustering Key Concepts Case Study Problems Bird's-Eye View What Is Data Key Concepts Feature Characteristics Bivariate Analysis Feature Space and Data Scatter Pre-Processing and Standardizing Mixed Data Similarity Data K-Means Clustering and Related Approaches Key Concepts Conventional K-Means Choice of K and Initialization of K-Means Intelligent K-Means: Iterated Anomalous Pattern Minkowski Metric K-Means and Feature Weighting Extensions of K-Means Clustering Overall Assessment Least-Squares Hierarchical Clustering Key Concepts Hierarchical Cluster Structures Agglomeration: Ward Algorithm Least-Squares Divisive Clustering Conceptual Clustering Extensions of Ward Clustering Overall Assessment Similarity Clustering: Uniform, Modularity, Additive, Spectral, Consensus and Single Linkage Key Concepts Summary Similarity Clustering Normalized Cut and Spectral Clustering Additive Clustering Consensus Clustering Single Linkage, Minimum Spanning Tree and Connected Components Overall Assessment Validation and Interpretation Key Concepts General: Internal and External Validity Testing Internal Validity Interpretation Aids in the Data Recovery Perspective Conceptual Description of Clusters Mapping Clusters to Knowledge Overall Assessment Least-Squares Data Recovery Clustering Models Key Concepts Statistics Modelling as Data Recovery K-Means as a Data Recovery Method Data Recovery Models for Hierarchical Clustering Data Recovery Models for Similarity Clustering Consensus and Ensemble Clustering Overall Assessment References Index

Bicliques for preimages: attacks on skein-512 and the SHA-2 family

Abstract: We present a new concept of biclique as a tool for preimage attacks, which employs many powerful techniques from differential cryptanalysis of block ciphers and hash functions. The new tool has proved to be widely applicable by inspiring many authors to publish new results of the full versions of AES, KASUMI, IDEA, and Square. In this paper, we show how our concept leads to the first cryptanalysis of the round-reduced Skein hash function, and describe an attack on the SHA-2 hash function with more rounds than before.

Using a Multilevel Structural Equation Modeling Approach to Explain Cross-Cultural Measurement Noninvariance

Abstract: Testing for invariance of measurements across groups (such as countries or time points) is essential before meaningful comparisons may be conducted. However, when tested, invariance is often absent. As a result, comparisons across groups are potentially problematic and may be biased. In the current study, we propose utilizing a multilevel structural equation modeling (SEM) approach to provide a framework to explain item bias. We show how variation in a contextual variable may explain noninvariance. For the illustration of the method, we use data from the second round of the European Social Survey (ESS).

Developing and Evaluating the Social Axioms Survey in Eleven Countries Its Relationship With the Five-Factor Model of Personality

Abstract: Based on a deductive, culturally decentered approach, new items were generated to improve the reliability of the original Social Axioms Survey, which measures individuals' general beliefs about the world. In Study 1, results from 11 countries support the original five-factor structure and achieve higher reliability for the axiom dimensions as measured by the new scale. Moreover, moderate but meaningful associations between axiom and Big-Five personality dimensions were found. Temporal change of social axioms at the culture level was examined and found to be moderate. In Study 2, additional new items were generated for social complexity and fate control, then assessed in Hong Kong and the United States. Reliability was further improved for both dimensions. Additionally, two subfactors of fate control were identified: fate determinism and fate alterability. Fate determinism, but not fate alterability, related positively to neuroticism. Other relationships between axiom and personality dimensions were similar to those reported in Study 1. The short forms of the axiom dimensions were generally reliable and correlated highly with the long forms. This research thus provides a stronger foundation for applying the construct of social axioms around the world.

Increasing absolute mortality disparities by education in Finland, Norway and Sweden, 1971–2000

Abstract: Background and objectives Studies on socioeconomic health disparities often suffer from a lack of uniform data and methodology. Using high quality, census-linked data and sensible inequality measures, this study documents the changes in absolute and relative mortality differences by education in Finland, Norway and Sweden over the period 1971 to 2000. Methods The age-standardised mortality rates and the population exposures for three educational categories were computed from detailed data provided by the national statistical offices. Mortality disparities by education were assessed using two range measures (rate differences and rate ratios), and two Gini-like measures (the average inter-group difference (AID) and the Gini coefficient (G)). The formulae for the decomposition of the change in the AID into (1) the contribution of change in population composition by education, and (2) the contribution of mortality change were introduced. Results Mortality decreases were often greater for high than for medium and low education. Both relative and absolute mortality disparities tend to increase over time. The magnitude and timing of the increases in absolute disparities vary by country. Both the rate differences and the AIDs have increased since the 1970s in Norway and Sweden, and since the 1980s in Finland. The contributions of the changes in population composition to the total AID increase were substantial in all countries, and for both sexes. The mortality contributions were substantial for males in Norway and Sweden. Conclusions The study reports increases in absolute mortality disparity, and its components. This trend needs to be further studied and addressed by policies.

Quantum toroidal gl1-algebra: Plane partitions

Abstract: In this, the third paper of the series, we construct a large family of representations of the quantum toroidal gl1-algebra whose bases are parameterized by plane partitions with various boundary conditions and restrictions. We study the corresponding formal characters. As an application we obtain a Gelfand–Zetlin-type basis for a class of irreducible lowest weight gl∞-modules.

The role of personal values and basic traits in perceptions of the consequences of immigration: A three nation study

Abstract: Using data from Italy, Spain, and Germany (N= 1,569), this study investigated the role of basic values (universalism and security) and basic traits (openness and agreeableness) in predicting perceptions of the consequences of immigration. In line with Schwartz's (1992) theory, we conceptualized security as having two distinct components, one concerned with safety of the self (personal security) and the other with harmony and stability of larger groups and of society (group security). Structural equation modelling revealed that universalism values underlie perceptions that immigration has positive consequences and group security values underlie perceptions that it has negative consequences. Personal security makes no unique, additional contribution. Multi-group analyses revealed that these associations are invariant across the three countries except for a stronger link between universalism and perceptions of the consequences of immigration in Spain. To examine whether values mediate relations of traits to perceptions of immigration, we used the five-factor model. Findings supported a full mediation model. Individuals' traits of openness and agreeableness explained significant variance in security and universalism values. Basic values, in turn, explained perceptions of the consequences of immigration.

Lattice Point Asymptotics and Volume Growth on Teichmuller space.

Abstract: We apply some of the ideas of the Ph.D. Thesis of G. A. Margulis (Mar70) to Teichmuller space. Let X be a point in Teichmuller space, and let BR(X) be the ball of radius R centered at X (with distances measured in the Teichmuller metric). We obtain asymptotic formulas as R tends to infinity for the volume of BR(X), and also for the cardinality of the intersection of BR(X) with an orbit of the mapping class group.

$${\mathbb{G}_a^ M}$$ degeneration of flag varieties

Abstract: Let \({\mathcal{F}_\lambda}\) be a generalized flag variety of a simple Lie group G embedded into the projectivization of an irreducible G-module Vλ. We define a flat degeneration \({\mathcal{F}_\lambda^a}\) , which is a \({\mathbb{G}^M_a}\) variety. Moreover, there exists a larger group Ga acting on \({\mathcal{F}_\lambda^a}\) , which is a degeneration of the group G. The group Ga contains \({\mathbb{G}^M_a}\) as a normal subgroup. If G is of type A, then the degenerate flag varieties can be embedde‘d into the product of Grassmannians and thus to the product of projective spaces. The defining ideal of \({\mathcal{F}_\lambda}\) is generated by the set of degenerate Plucker relations. We prove that the coordinate ring of \({\mathcal{F}_\lambda^a}\) is isomorphic to a direct sum of dual PBW-graded \({\mathfrak{g}}\) -modules. We also prove that there exists bases in multi-homogeneous components of the coordinate rings, parametrized by the semistandard PBW-tableux, which are analogs of semistandard tableaux.

Quiver Grassmannians and degenerate flag varieties

Abstract: Quiver Grassmannians are varieties parametrizing subrepresentations of a quiver representation. It is observed that certain quiver Grassmannians for type A quivers are isomorphic to the degenerate flag varieties investigated earlier by the second named author. This leads to the consideration of a class of Grassmannians of subrepresentations of the direct sum of a projective and an injective representation of a Dynkin quiver. It is proven that these are (typically singular) irreducible normal local complete intersection varieties, which admit a group action with finitely many orbits, and a cellular decomposition. For type A quivers explicit formulas for the Euler characteristic (the median Genocchi numbers) and the Poincare polynomials are derived.

Robust Data Mining

Abstract: Data uncertainty is a concept closely related with most real life applications that involve data collection and interpretation. Examples can be found in data acquired with biomedical instruments or other experimental techniques. Integration of robust optimization in the existing data mining techniques aim to create new algorithms resilient to error and noise. This work encapsulates all the latest applications of robust optimization in data mining. This brief contains an overview of the rapidly growing field ofrobust data mining research field and presents the most well known machine learning algorithms, their robust counterpart formulations and algorithms for attacking these problems. Thisbrief will appeal to theoreticians and data miners working in this field.

Flag varieties, toric varieties, and suspensions: Three instances of infinite transitivity

Abstract: We say that a group acts infinitely transitively on a set if for every the induced diagonal action of is transitive on the cartesian th power with the diagonals removed. We describe three classes of affine algebraic varieties such that their automorphism groups act infinitely transitively on their smooth loci. The first class consists of normal affine cones over flag varieties, the second of nondegenerate affine toric varieties, and the third of iterated suspensions over affine varieties with infinitely transitive automorphism groups. Bibliography: 42 titles.

Instanton bundles on Fano threefolds

Abstract: We introduce the notion of an instanton bundle on a Fano threefold of index 2. For such bundles we give an analogue of a monadic description and discuss the curve of jumping lines. The cases of threefolds of degree 5 and 4 are considered in a greater detail.

Intellectual Capital Transformation Evaluating Model

Abstract: Purpose – The purpose of this paper is to present a framework that is developed for analysis of intellectual capital transformation into companies’ value, including an identification of the key factors of this process.Design/methodology/approach – The paper employs intellectual capital on the intersection of value‐based management (VBM) and the resource‐based view (RBV). Starting from a review of the results provided in the literature regarding intellectual capital (IC) evaluation and its link with firm performance, a system of proxy indicators related to IC transformation in both concepts has been designed. The evaluation ability of the developed model was justified using regression analyses.Findings – A detailed algorithm for intellectual capital evaluation in terms of input‐outcome transformation. The intellectual capital transformation evaluating model (ICTEM) provides a holistic view of intellectual resources as companies’ strategic investments.Research limitations/implications – The paper emphasizes...