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## Um estudo sobre o papel de medidas de similaridade em visualização de coleções de documentos; A study on the role of similarity measures in visual text analytics

Fonte: Biblioteca Digitais de Teses e Dissertações da USP
Publicador: Biblioteca Digitais de Teses e Dissertações da USP

Tipo: Dissertação de Mestrado
Formato: application/pdf

Publicado em 27/09/2012
PT

Relevância na Pesquisa

46.09%

#Análise visual de textos#High-dimensional data visualization and multidimensional projections#Mineração visual de textos#Modelo espaço vetorial#Vector space model#Visual text analytics#Visual text mining#Visualização de dados com alta dimensionalidade e projeções multidimensionais

Técnicas de visualização de informação, tais como as que utilizam posicionamento de pontos baseado na similaridade do conteúdo, são utilizadas para criar representações visuais de dados que evidenciem certos padrões. Essas técnicas são sensíveis à qualidade dos dados, a qual, por sua vez, depende de uma etapa de pré-processamento muito influente. Esta etapa envolve a limpeza do texto e, em alguns casos, a detecção de termos e seus pesos, bem como a definição de uma função de (dis)similaridade. Poucos são os estudos realizados sobre como esses cálculos de (dis)similaridade afetam a qualidade das representações visuais geradas para dados textuais. Este trabalho apresenta um estudo sobre o papel das diferentes medidas de (dis)similaridade entre pares de textos na geração de mapas visuais. Nos concentramos principalmente em dois tipos de funções de distância, aquelas computadas a partir da representação vetorial do texto (Vector Space Model (VSM)) e em medidas de comparação direta de strings textuais. Comparamos o efeito na geração de mapas visuais com técnicas de posicionamento de pontos, utilizando as duas abordagens. Para isso, foram utilizadas medidas objetivas para comparar a qualidade visual dos mapas...

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## Three-phase tri-state integrated boost inverter with special space vector and dq0 control

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Conferência ou Objeto de Conferência
Formato: 644-648

ENG

Relevância na Pesquisa

46.07%

#New Space Vector Modulation#Stand-Alone and Grid Connected PV applications#Three-phase Integrated Inverter#Boost inverters#Degree of freedom#Dq0 transformation#Grid-connected#Grid-connected PV#Integrated inverter#Space Vector#Space Vector Modulation

This paper presents a three-phase integrated inverter suitable for stand-alone and grid-connected applications. Furthermore, the utilization of the special features of the tri-state coupled with the new space vector modulation allows the converter to present an attractive degree of freedom for the designing of the controllers. Additionally, the control is derived through dq0 transformation, all the system is described and interesting simulation results are available to confirm the proposal. © 2012 IEEE.

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## The development and assessment of the semantic fields model of visual salience.

Fonte: Universidade de Adelaide
Publicador: Universidade de Adelaide

Tipo: Tese de Doutorado

Publicado em //2010

Relevância na Pesquisa

46%

#visual salience#semantic modeling#eye tracking#semantic fields#web pages#vector space#latent semantic analysis#topic model#non-negative matrix factorization#pupil dilation

The present thesis describes the development and assessment of the Semantic Fields Model of visual salience. The Semantic Fields model provides estimates of visual salience in relation to goal-oriented Web site search tasks. The development and assessment of this model is reported over seven studies that are presented in two journal articles and two peer-reviewed conference papers. In Paper 1 (N=50), pupil dilation is validated as a measure of cognitive load for use in later studies. While it has been found previously that a participant’s pupil dilation will be larger during more complex tasks, these experiments have not generally been conducted under the environmental condition of light radiated from a computer monitor. The findings of this experiment indicate that computer monitor radiance in our experimental setting did not interfere with the ability to discriminate successfully between task-related pupil dilation. Paper 2 (N=49) introduces the Semantic Fields model for estimating the visual salience of different areas displayed on a Web page. Latent Semantic Analysis and the Touchstone Applied Science Associates (TASA) corpus were used to calculate Semantic Field values for any (x, y) coordinate point on a Web page based on the structure of that Web page. These Semantic Field values were then used to estimate eye-tracking data that was collected from participants’ goal-oriented search tasks on a total of 1842 Web pages. Semantic Field values were found to predict the participants’ eye-tracking data. In Paper 3 (N=100)...

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## A context vector model for information retrieval

Fonte: Wiley & Sons
Publicador: Wiley & Sons

Tipo: Artigo de Revista Científica
Formato: application/pdf

Publicado em //2002
ENG

Relevância na Pesquisa

56.07%

#Vector space models#Document retrieval#Vector analysis#Co-occurrence analysis#Contextual information#Informática

In the vector space model for information retrieval, term vectors are pair-wise orthogonal, that is, terms are assumed to be independent. It is well known that this assumption is too restrictive. In this article, we present our work on an indexing and retrieval method that, based on the vector space model, incorporates term dependencies and thus obtains semantically richer representations of documents. First, we generate term context vectors based on the co-occurrence of terms in the same documents. These vectors are used to calculate context vectors for documents. We present different techniques for estimating the dependencies among terms. We also define term weights that can be employed in the model. Experimental results on four text collections (MED, CRANFIELD, CISI, and CACM) show that the incorporation of term dependencies in the retrieval process performs statistically significantly better than the classical vector space model with IDF weights. We also show that the degree of semantic matching versus direct word matching that performs best varies on the four collections. We conclude that the model performs well for certain types of queries and, generally, for information tasks with high recall requirements. Therefore, we propose the use of the context vector model in combination with other...

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## Large vector spaces of block-symmetric strong linearizations of matrix polynomials

Fonte: Elsevier
Publicador: Elsevier

Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article

Publicado em 15/07/2015
ENG

Relevância na Pesquisa

55.95%

#block-symmetric linearizations#Fiedler pencils with repetition#generalized Fiedler pencils with repetition#matrix polynomials#strong linearizations#structured matrix polynomials#vector space DL(P)#Matemáticas

Given a matrix polynomial P(lambda) = Sigma(k)(i=0) lambda(i) A(i) of degree k, where A(i) are n x n matrices with entries in a field F, the development of linearizations of P(lambda) that preserve whatever structure P(lambda) might posses has been a very active area of research in the last decade. Most of the structure-preserving linearizations of P(lambda) discovered so far are based on certain modifications of block-symmetric linearizations. The block-symmetric linearizations of P(lambda) available in the literature fall essentially into two classes: linearizations based on the so-called Fiedler pencils with repetition, which form a finite family, and a vector space of dimension k of block-symmetric pencils, called DL(P), such that most of its pencils are linearizations. One drawback of the pencils in DL(P) is that none of them is a linearization when P(lambda) is singular. In this paper we introduce new vector spaces of block,symmetric pencils, most of which are strong linearizations of P(lambda). The dimensions of these spaces are O(n(2)), which, for n >= root k, are much larger than the dimension of DL(P). When k is odd, many of these vector spaces contain linearizations also when P(lambda) is singular. The coefficients of the block-symmetric pencils in these new spaces can be easily constructed as k x k block-matrices whose n x n blocks are of the form 0...

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## Making clustering in delay-vector space meaningful

Fonte: Springer
Publicador: Springer

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

55.87%

Sequential time series clustering is a technique used to extract important features from time series data. The method can be shown to be the process of clustering in the delay-vector space formalism used in the Dynamical Systems literature. Recently, the

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## Some necessary conditions for vector space partitions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

46%

Some new necessary conditions for the existence of vector space partitions
are derived. They are applied to the problem of finding the maximum number of
spaces of dimension t in a vector space partition of V(2t,q) that contains m_d
spaces of dimension d, where t/2

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## Partial derivatives of a generic subspace of a vector space of forms: quotients of level algebras of arbitrary type

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

46%

Given a vector space $V$ of homogeneous polynomials of the same degree over
an infinite field, consider a generic subspace $W$ of $V$. The main result of
this paper is a lower-bound (in general sharp) for the dimensions of the spaces
spanned in each degree by the partial derivatives of the forms generating $W$,
in terms of the dimensions of the spaces spanned by the partial derivatives of
the forms generating the original space $V$. Rephrasing our result in the
language of commutative algebra (where this result finds its most important
applications), we have: let $A$ be a type $t$ artinian level algebra with
$h$-vector $h=(1,h_1,h_2,...,h_e)$, and let, for $c=1,2,...,t-1$,
$H^{c,gen}=(1,H_1^{c,gen},H_2^{c,gen},...,H_e^{c,gen})$ be the $h$-vector of
the generic type $c$ level quotient of $A$ having the same socle degree $e$.
Then we supply a lower-bound (in general sharp) for the $h$-vector $H^{c,gen}$.
Explicitly, we will show that, for any $u\in \lbrace 1,...,e\rbrace $,
$$H_u^{c,gen}\geq {1\over t^2-1}((t-c)h_{e-u}+(ct-1)h_u).$$ This result
generalizes a recent theorem of Iarrobino (which treats the case $t=2$).
Finally, we begin to obtain, as a consequence, some structure theorems for
level $h$-vectors of type bigger than 2, which is...

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## Entanglement Sharing in Real-Vector-Space Quantum Theory

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

46%

The limitation on the sharing of entanglement is a basic feature of quantum
theory. For example, if two qubits are completely entangled with each other,
neither of them can be at all entangled with any other object. In this paper we
show, at least for a certain standard definition of entanglement, that this
feature is lost when one replaces the usual complex vector space of quantum
states with a real vector space. Moreover, the difference between the two
theories is extreme: in the real-vector-space theory, there exist states of
arbitrarily many binary objects, "rebits," in which every rebit in the system
is maximally entangled with each of the other rebits.; Comment: 13 pages; minor corrections in v2

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## Vector cross product in n-dimensional vector space

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 18/10/2013

Relevância na Pesquisa

46.08%

The definition of vector cross product (VCP) introduced by Eckmann only
exists in thethree- and the seven- dimensional vector space. In this paper,
according to the orthogonal completeness, magnitude of basis vector cross
product and all kinds of combinations of basis vector $\hat{e}_i$, the
generalized definition of VCP in the odd n-dimensional vector space is given by
introducing a cross term $X_{AB}$. In addition, the definition is validated by
reducing the generalization definition to the fundamental three- and
seven-dimensional vector space.; Comment: 9 pages, 1 figure, comments are welcome

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## A survey of the different types of vector space partitions

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 05/03/2011

Relevância na Pesquisa

46.16%

A {\it vector space partition} is here a collection $\mathcal P$ of subspaces
of a finite vector space $V(n,q)$, of dimension $n$ over a finite field with
$q$ elements, with the property that every non zero vector is contained in a
unique member of $\mathcal P$. Vector space partitions relates to finite
projective planes, design theory and error correcting codes.
In the first part of the talk I will discuss some relations between vector
space partitions and other branches of mathematics. The other part of the talk
contains a survey of known results on the type of a vector space partition,
more precisely: the theorem of Beutelspacher and Heden on
$\mathrm{T}$-partitions, rather recent results of El-Zanati et al. on the
different types that appear in the spaces V(n,2), for $n\leq8$, a result of
Heden and Lehmann on vector space partitions and maximal partial spreads
including their new necessary condition for the existence of a vector space
partition, and furthermore, I will give a theorem of Heden on the length of the
tail of a vector space partition.
Finally, I will also give a few historical remarks.; Comment: This talk was presented at Matematiska kollokviet at Department of
Mathematics at Link\"oping University on May 19, 2010

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## Sp(2,$\mathbb{Z}$) invariant Wigner function on even dimensional vector space

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 31/01/2013

Relevância na Pesquisa

46.05%

We construct the quasi probability distribution $W(p,q)$ on even dimensional
vector space with marginality and invariance under the transformation induced
by projective representation of the group ${\rm Sp}(2,\mathbb{Z})$ whose
elements correspond to linear canonical transformation.
On even dimensional vector space, non-existence of such a quasi probability
distribution whose arguments take physical values was shown in our previous
paper(Phys.Rev.A{\bf 65} 032105(2002)). For this reason we study a quasi
probability distribution $W(p,q)$ whose arguments $q$ and $p$ take not only $N$
physical values but also $N$ unphysical values, where $N$ is dimension of
vector space. It is shown that there are two quasi probability distributions on
even dimensional vector space. The one is equivalent to the Wigner function
proposed by Leonhardt, and the other is a new one.; Comment: 5 pages

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## Vector-Space Markov Random Fields via Exponential Families

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 19/05/2015

Relevância na Pesquisa

46%

We present Vector-Space Markov Random Fields (VS-MRFs), a novel class of
undirected graphical models where each variable can belong to an arbitrary
vector space. VS-MRFs generalize a recent line of work on scalar-valued,
uni-parameter exponential family and mixed graphical models, thereby greatly
broadening the class of exponential families available (e.g., allowing
multinomial and Dirichlet distributions). Specifically, VS-MRFs are the joint
graphical model distributions where the node-conditional distributions belong
to generic exponential families with general vector space domains. We also
present a sparsistent $M$-estimator for learning our class of MRFs that
recovers the correct set of edges with high probability. We validate our
approach via a set of synthetic data experiments as well as a real-world case
study of over four million foods from the popular diet tracking app
MyFitnessPal. Our results demonstrate that our algorithm performs well
empirically and that VS-MRFs are capable of capturing and highlighting
interesting structure in complex, real-world data. All code for our algorithm
is open source and publicly available.; Comment: See https://github.com/tansey/vsmrfs for code

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## The Bloch-vector space for N-level systems -- the spherical-coordinate point of view

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

46.05%

Bloch-vector spaces for $N$-level systems are investigated from the
spherical-coordinate point of view in order to understand their geometrical
aspects. We show that the maximum radius in each direction, which is due to the
construction of the Bloch-vector space, is determined by the minimum eigenvalue
of the corresponding observable (orthogonal generator of SU(N)). From this
fact, we reveal the dual property of the structure of the Bloch-vector space;
if in some direction the space reachs the large sphere (pure state), then in
the opposite direction the space can only get to the small sphere, and vice
versa. Another application is a parameterization with simple ranges of density
operators. We also provide three classes of quantum-state representation based
on actual measurements beyond the Bloch vector and discuss their state-spaces.; Comment: REVTeX4, 25 pages, 3 EPS figures, Rewritten with improved
explanation; references add

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## The Clustering of Author's Texts of English Fiction in the Vector Space of Semantic Fields

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 06/12/2012

Relevância na Pesquisa

46%

#Computer Science - Computation and Language#Computer Science - Digital Libraries#Computer Science - Information Retrieval

The clustering of text documents in the vector space of semantic fields and
in the semantic space with orthogonal basis has been analysed. It is shown that
using the vector space model with the basis of semantic fields is effective in
the cluster analysis algorithms of author's texts in English fiction. The
analysis of the author's texts distribution in cluster structure showed the
presence of the areas of semantic space that represent the author's ideolects
of individual authors. SVD factorization of the semantic fields matrix makes it
possible to reduce significantly the dimension of the semantic space in the
cluster analysis of author's texts.; Comment: 7 pages, 5 figures

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## Group-theoretical vector space model

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 20/09/2015

Relevância na Pesquisa

46.03%

This paper presents a group-theoretical vector space model (VSM) that extends
the VSM with a group action on a vector space of the VSM. We use group and its
representation theory to represent a dynamic transformation of information
objects, in which each information object is represented by a vector in a
vector space of the VSM. Several groups and their matrix representations are
employed for representing different kinds of dynamic transformations of
information objects used in the VSM. We provide concrete examples of how a
dynamic transformation of information objects is performed and discuss
algebraic properties involving certain dynamic transformations of information
objects used in the VSM.; Comment: This is an Accepted Manuscript of an article published by Taylor &
Francis Group in International Journal of Computer Mathematics on 16/09/2014,
available online: http://dx.doi.org/10.1080/00207160.2014.958079

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## Metrizability of Topological Vector Space Valued Cone Metric Spaces

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

46.03%

Scalarization method is an important tool in the study of vector optimization
as corresponding solutions of vector optimization problems can be found by
solving scalar optimization problems. This is applied by Du (2010) [A note on
cone metric fixed point theory and its equivalence, Nonlinear Analysis 72
2259-2261] to investigate the equivalence of vectorial versions of fixed point
theorems of contractive mappings in generalized cone metric spaces and scalar
versions of fixed point theorems in general metric spaces in usual sense. In
this paper we find out that the topology induced by topological vector space
valued cone metric coincides with the topology induced by the metric obtained
via a nonlinear scalarization function, i.e any topological vector space valued
cone metric space is metrizable.; Comment: This paper has been withdrawn by the authors. We withdraw our paper
due to the acceptance in the journal "Applied Mathematics Letters" with a
different title. r has been withdrawn by the authors due to a

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## Vector space framework for unification of one- and multidimensional filter bank theory

Fonte: Instituto de Tecnologia da Califórnia
Publicador: Instituto de Tecnologia da Califórnia

Tipo: Article; PeerReviewed
Formato: application/pdf

Publicado em /08/1994

Relevância na Pesquisa

46.09%

A number of results in filter bank theory can be viewed using vector space notations. This simplifies the proofs of many important results. In this paper, we first introduce the framework of vector space, and then use this framework to derive some known and some new filter bank results as well. For example, the relation among the Hermitian image property, orthonormality, and the perfect reconstruction (PR) property is well-known for the case of one-dimensional (1-D) analysis/synthesis filter banks. We can prove the same result in a more general vector space setting. This vector space framework has the advantage that even the most general filter banks, namely, multidimensional nonuniform filter banks with rational decimation matrices, become a special case. Many results in 1-D filter bank theory are hence extended to the multidimensional case, with some algebraic manipulations of integer matrices. Some examples are: the equivalence of biorthonormality and the PR property, the interchangeability of analysis and synthesis filters, the connection between analysis/synthesis filter banks and synthesis/analysis transmultiplexers, etc. Furthermore, we obtain the subband convolution scheme by starting from the generalized Parseval's relation in vector space. Several theoretical results of wavelet transform can also be derived using this framework. In particular...

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## Soft Similarity and Soft Cosine Measure: Similarity of Features in Vector Space Model

Fonte: Centro de Investigación en computación, IPN
Publicador: Centro de Investigación en computación, IPN

Tipo: Artigo de Revista Científica
Formato: text/html

Publicado em 01/09/2014
EN

Relevância na Pesquisa

65.96%

#Soft similarity#soft cosine measure#vector space model#similarity between features#Levenshtein distance#n-grams#syntactic n-grams

We show how to consider similarity between features for calculation of similarity of objects in the Vector Space Model (VSM) for machine learning algorithms and other classes of methods that involve similarity between objects. Unlike LSA, we assume that similarity between features is known (say, from a synonym dictionary) and does not need to be learned from the data. We call the proposed similarity measure soft similarity. Similarity between features is common, for example, in natural language processing: words, n-grams, or syntactic n-grams can be somewhat different (which makes them different features) but still have much in common: for example, words "play" and "game" are different but related. When there is no similarity between features then our soft similarity measure is equal to the standard similarity. For this, we generalize the well-known cosine similarity measure in VSM by introducing what we call "soft cosine measure". We propose various formulas for exact or approximate calculation of the soft cosine measure. For example, in one of them we consider for VSM a new feature space consisting of pairs of the original features weighted by their similarity. Again, for features that bear no similarity to each other, our formulas reduce to the standard cosine measure. Our experiments show that our soft cosine measure provides better performance in our case study: entrance exams question answering task at CLEF. In these experiments...

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## Vector Space Basis Change in Information Retrieval

Fonte: Centro de Investigación en computación, IPN
Publicador: Centro de Investigación en computación, IPN

Tipo: Artigo de Revista Científica
Formato: text/html

Publicado em 01/09/2014
EN

Relevância na Pesquisa

66.07%

The Vector Space Basis Change (VSBC) is an algebraic operator responsible for change of basis and it is parameterized by a transition matrix. If we change the vector space basis, then each vector component changes depending on this matrix. The strategy of VSBC has been shown to be effective in separating relevant documents and irrelevant ones. Recently, using this strategy, some feedback algorithms have been developed. To build a transition matrix some optimization methods have been used. In this paper, we propose to use a simple, convenient and direct method to build a transition matrix. Based on this method we develop a relevance feedback algorithm. Experimental results on a TREC collection show that our proposed method is effective and generally superior to known VSBC-based models. We also show that our proposed method gives a statistically significant improvement over these models.

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