195 research outputs found
Reconocimiento mineralógico de cerámicas árabes
Las muestras de cerámicas árabes estudiadas, presentan una composición mineralógica derivadas
de haber sido cocidas a temperaturas comprendidas entre 800 y 1000ÂşC. Todas ellas
tienen en comĂşn la utilizaciĂłn de cuarzo y feldespatos como desgrasantes. El yacimiento contiene piezas muy diversas, hecho que guarda relaciĂłn con su emplazamiento.A study of arab ceramics fragments, shows a mineralogical composition derived from the fact that they probably were fired at a temperature between 800-1000ÂşC. Every samples have
in common the temper composition in quartz and feldspars. The deposit includes ceramics from several procedences, according to its location
Estructura cristalina de la succinodiamidoxima (c4h10n4o2)
Se ha determinado la estructura cristalina de la succinodiamidoxima. Pertenece al sistema monoclĂnico; P21/n; a=4.883(1), b=5.197(2), c=13.283(2) A, β=100.75(2)Âş; V=331.2(2 ) A3; Z=2; M=146.149; Dcal.=1.465 Mg.m-3; λ=1.5405 A; ÎĽ=9.625 cm-1;F(000) =156; valor final de R=0.040, para 2207 reflexiones observadas, medidas a temperatura ambiente; Rw=0.036.Monoclinic P21/n; a=4.883(1), b=5.197(2), c=13.283(2) A, β=100.75(2)Âş; V=331.2(2 ) A3; Z=2; M=146.149; Dcal.=1.465 Mg.m-3; λ=1.5405 A; ÎĽ=9.625 cm-1;F(000) =156; R=0.040, four 2207 observed reflexions, room temperature; Rw=0.036
Reconocimiento mineralógico de cerámicas árabes
Las muestras de cerámicas árabes estudiadas, presentan una composición mineralógica derivadas
de haber sido cocidas a temperaturas comprendidas entre 800 y 1000ÂşC. Todas ellas
tienen en comĂşn la utilizaciĂłn de cuarzo y feldespatos como desgrasantes. El yacimiento contiene piezas muy diversas, hecho que guarda relaciĂłn con su emplazamiento.A study of arab ceramics fragments, shows a mineralogical composition derived from the fact that they probably were fired at a temperature between 800-1000ÂşC. Every samples have
in common the temper composition in quartz and feldspars. The deposit includes ceramics from several procedences, according to its location
Estructura cristalina de la succinodiamidoxima (c4h10n4o2)
Se ha determinado la estructura cristalina de la succinodiamidoxima. Pertenece al sistema monoclĂnico; P21/n; a=4.883(1), b=5.197(2), c=13.283(2) A, β=100.75(2)Âş; V=331.2(2 ) A3; Z=2; M=146.149; Dcal.=1.465 Mg.m-3; λ=1.5405 A; ÎĽ=9.625 cm-1;F(000) =156; valor final de R=0.040, para 2207 reflexiones observadas, medidas a temperatura ambiente; Rw=0.036.Monoclinic P21/n; a=4.883(1), b=5.197(2), c=13.283(2) A, β=100.75(2)Âş; V=331.2(2 ) A3; Z=2; M=146.149; Dcal.=1.465 Mg.m-3; λ=1.5405 A; ÎĽ=9.625 cm-1;F(000) =156; R=0.040, four 2207 observed reflexions, room temperature; Rw=0.036
Redundancy, Deduction Schemes, and Minimum-Size Bases for Association Rules
Association rules are among the most widely employed data analysis methods in
the field of Data Mining. An association rule is a form of partial implication
between two sets of binary variables. In the most common approach, association
rules are parameterized by a lower bound on their confidence, which is the
empirical conditional probability of their consequent given the antecedent,
and/or by some other parameter bounds such as "support" or deviation from
independence. We study here notions of redundancy among association rules from
a fundamental perspective. We see each transaction in a dataset as an
interpretation (or model) in the propositional logic sense, and consider
existing notions of redundancy, that is, of logical entailment, among
association rules, of the form "any dataset in which this first rule holds must
obey also that second rule, therefore the second is redundant". We discuss
several existing alternative definitions of redundancy between association
rules and provide new characterizations and relationships among them. We show
that the main alternatives we discuss correspond actually to just two variants,
which differ in the treatment of full-confidence implications. For each of
these two notions of redundancy, we provide a sound and complete deduction
calculus, and we show how to construct complete bases (that is,
axiomatizations) of absolutely minimum size in terms of the number of rules. We
explore finally an approach to redundancy with respect to several association
rules, and fully characterize its simplest case of two partial premises.Comment: LMCS accepted pape
A Hierarchy of Polynomial Kernels
In parameterized algorithmics, the process of kernelization is defined as a
polynomial time algorithm that transforms the instance of a given problem to an
equivalent instance of a size that is limited by a function of the parameter.
As, afterwards, this smaller instance can then be solved to find an answer to
the original question, kernelization is often presented as a form of
preprocessing. A natural generalization of kernelization is the process that
allows for a number of smaller instances to be produced to provide an answer to
the original problem, possibly also using negation. This generalization is
called Turing kernelization. Immediately, questions of equivalence occur or,
when is one form possible and not the other. These have been long standing open
problems in parameterized complexity. In the present paper, we answer many of
these. In particular, we show that Turing kernelizations differ not only from
regular kernelization, but also from intermediate forms as truth-table
kernelizations. We achieve absolute results by diagonalizations and also
results on natural problems depending on widely accepted complexity theoretic
assumptions. In particular, we improve on known lower bounds for the kernel
size of compositional problems using these assumptions
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