Search results for "topology"

Discovering unbounded unions of regular pattern languages from positive examples

1996

The problem of learning unions of certain pattern languages from positive examples is considered. We restrict to the regular patterns, i.e., patterns where each variable symbol can appear only once, and to the substring patterns, which is a subclass of regular patterns of the type xαy, where x and y are variables and α is a string of constant symbols. We present an algorithm that, given a set of strings, finds a good collection of patterns covering this set. The notion of a ‘good covering’ is defined as the most probable collection of patterns likely to be present in the examples, assuming a simple probabilistic model, or equivalently using the Minimum Description Length (MDL) principle. Ou…

2020

Hierarchy and centrality are two popular notions used to characterize the importance of entities in complex systems. Indeed, many complex systems exhibit a natural hierarchical structure, and centrality is a fundamental characteristic allowing to identify key constituents. Several measures based on various aspects of network topology have been proposed in order to quantify these concepts. While numerous studies have investigated whether centrality measures convey redundant information, how centrality and hierarchy measures are related is still an open issue. In this paper, we investigate the association between centrality and hierarchy using several correlation and similarity evaluation mea…

Building an Optimal WSD Ensemble Using Per-Word Selection of Best System

2006

In Senseval workshops for evaluating WSD systems [1,4,9], no one system or system type (classifier algorithm, type of system ensemble, extracted feature set, lexical knowledge source etc.) has been discovered that resolves all ambiguous words into their senses in a superior way. This paper presents a novel method for selecting the best system for target word based on readily available word features (number of senses, average amount of training per sense, dominant sense ratio). Applied to Senseval-3 and Senseval-2 English lexical sample state-of-art systems, a net gain of approximately 2.5 – 5.0% (respectively) in average precision per word over the best base system is achieved. The method c…

Smart logistics as a basis for the development of the smart city

2019

Abstract In this article the issues of role and meaning of intelligent technologies has been undertaken especially in area of logistics, without which development of smart cities would be actually impossible. Even though we can argue about it, what it actually means “intelligent”, without a doubt it covers use of modern Technologies. They let to reduce negative influence of flow of good and people in urbanized areas, at the same time they increase level of quality of life in the city. In the article we discussed a trial of defining concept of ‘smart city’. As a main goal we set indication of result in area of smart logistics, that let to optimize logistic processes through digitalization an…

History of Data Centre Development

2012

International audience; Computers are used to solve different problems. For solving these problems computer software and hardware are used, but for operations of those computing facilities a Data Centre is necessary. Therefore, development of the data centre is subordinated to solvable tasks and computing resources. We are studying the history of data centres’ development, taking into consideration an understanding of this. In the beginning of the computer era computers were installed in computing centres, because all computing centres have defined requirements according to whom their operation is intended for. Even though the concept of ‘data centre’ itself has been used since the 1990s, t…

The development of a suite of computer-based diagnostic tests based on the Common European Framework

2005

DIALANG is an on-line language assessment system, which contains tests in 14 European languages and is based on the Common European Framework of Reference (CEFR). It is the first major testing system that is oriented towards diagnosing language skills and providing feedback to users rather than certifying their proficiency. This article describes the contents of Version 1 of DIALANG and the way in which the system works. This is followed by an account of the development of DIALANG tests and of the pilot testing and standard setting procedures. The results of the first analyses of items and self-assessment statements, and of the standard setting procedures, are reported. The article focuses…

OPERADS AND JET MODULES

2005

Let $A$ be an algebra over an operad in a cocomplete closed symmetric monoidal category. We study the category of $A$-modules. We define certain symmetric product functors of such modules generalising the tensor product of modules over commutative algebras, which we use to define the notion of a jet module. This in turn generalises the notion of a jet module over a module over a classical commutative algebra. We are able to define Atiyah classes (i.e. obstructions to the existence of connections) in this generalised context. We use certain model structures on the category of $A$-modules to study the properties of these Atiyah classes. The purpose of the paper is not to present any really de…

Projective models of K3 surfaces with an even set

2006

The aim of this paper is to describe algebraic K3 surfaces with an even set of rational curves or of nodes. Their minimal possible Picard number is nine. We completely classify these K3 surfaces and after a carefull analysis of the divisors contained in the Picard lattice we study their projective models, giving necessary and sufficient conditions to have an even set. Moreover we investigate their relation with K3 surfaces with a Nikulin involution.

Moduli spaces of rank two aCM bundles on the Segre product of three projective lines

2016

Let P^n be the projective space of dimension n on an algebraically closed field of characteristic 0 and F be the image of the Segre embedding of P^1xP^1xP^1 inside P^7. In the present paper we deal with the moduli spaces of locally free sheaves E on F of rank 2 with h^i(F,E(t))=0 for i=1,2 and each integer t.

The proof of Birman’s conjecture on singular braid monoids

2003

Let B_n be the Artin braid group on n strings with standard generators sigma_1, ..., sigma_{n-1}, and let SB_n be the singular braid monoid with generators sigma_1^{+-1}, ..., sigma_{n-1}^{+-1}, tau_1, ..., tau_{n-1}. The desingularization map is the multiplicative homomorphism eta: SB_n --> Z[B_n] defined by eta(sigma_i^{+-1}) =_i^{+-1} and eta(tau_i) = sigma_i - sigma_i^{-1}, for 1 <= i <= n-1. The purpose of the present paper is to prove Birman's conjecture, namely, that the desingularization map eta is injective.