973 research outputs found
Usage-based and emergentist approaches to language acquisition
It was long considered to be impossible to learn grammar based on linguistic experience alone. In the past decade, however, advances in usage-based linguistic theory, computational linguistics, and developmental psychology changed the view on this matter. So-called usage-based and emergentist approaches to language acquisition state that language can be learned from language use itself, by means of social skills like joint attention, and by means of powerful generalization mechanisms. This paper first summarizes the assumptions regarding the nature of linguistic representations and processing. Usage-based theories are nonmodular and nonreductionist, i.e., they emphasize the form-function relationships, and deal with all of language, not just selected levels of representations. Furthermore, storage and processing is considered to be analytic as well as holistic, such that there is a continuum between children's unanalyzed chunks and abstract units found in adult language. In the second part, the empirical evidence is reviewed. Children's linguistic competence is shown to be limited initially, and it is demonstrated how children can generalize knowledge based on direct and indirect positive evidence. It is argued that with these general learning mechanisms, the usage-based paradigm can be extended to multilingual language situations and to language acquisition under special circumstances
Gliridae (Rodentia, Mammalia) del Mioceno inferior de la fisura kĂĄrstica Rinascita 1 (Gargano, prov. Foggia, Italy).
Two new species of the endemic genus Stertomys (Mammalia, Rodentia, Gliridae) are described from the Late Miocene fissure filling Rinascita 1 on the palaeo-island Gargano (prov. Foggia, Italy): S. simplex and S. lyrifer. A third species is classified as S. aff. daamsi Freudenthal & MartĂn-SuĂĄrez, 2006. The fauna contains poor remains of three more species of Stertomys, and a non-endemic glirid: Dryomys apulus Freudenthal & MartĂn-SuĂĄrez, 2006. Two groups of species are recognized within the genus Stertomys:
1) Large species with complicated dental pattern: S. laticrestatus Daams & Freudenthal, 1985, S. daunius Freudenthal & MartĂn-SuĂĄrez, 2006, and S. lyrifer sp. nov.
2) Smaller species with a simpler dental pattern: S. daamsi Freudenthal & MartĂn-SuĂĄrez, 2006, S. simplex sp. nov., and S. aff. daamsi.
Key words: Gliridae, Miocene, Italy, endemism, insularity.Se describen dos especies nuevas del gĂ©nero endĂ©mico Stertomys (Mammalia, Rodentia, Gliridae) de la fisura kĂĄrstica Rinascita 1 en la paleo-isla de Gargano (prov. Foggia, Italia): S. simplex y S. lyrifer. Una tercera especie se clasifica como S. aff. daamsi Freudenthal & MartĂn-SuĂĄrez, 2006. La fauna contiene tres especies de Stertomys mĂĄs, que estĂĄn representadas por muy poco material. Hay ademĂĄs un glirido no endĂ©mico: Dryomys apulus Freudenthal & MartĂn-SuĂĄrez, 2006.
Se reconocen dos grupos de especies en el género Stertomys:
1) Especies grandes con denticiĂłn complicada: S. laticrestatus Daams & Freudenthal, 1985, S. daunius Freudenthal & MartĂn-SuĂĄrez, 2006, y S. lyrifer sp. nov.
2) Especies mĂĄs pequeñas con denticiĂłn mĂĄs sencilla: S. daamsi Freudenthal & MartĂn-SuĂĄrez, 2006, S. simplex sp. nov., y S. aff. daamsi.
Palabras clave: Gliridae, Mioceno, Italia, endemismo, insularidad
Cognitive modelling of language acquisition with complex networks
ABSTRACT Cognitive modelling is a well-established computational intelligence tool, which is very useful for studying cognitive phenomena, such as young children's first language acquisition. Specifically, linguistic modelling has recently benefited greatly from complex network theory by modelling large sets of empirical linguistic data as complex networks, thereby illuminating interesting new patterns and trends. In this chapter, we show how simple network analysis techniques can be applied to the study of language acquisition, and we argue that they reveal otherwise hidden information. We also note that a key network parameter -the ranked frequency distribution of the links -provides useful knowledge about the data, even though it had been previously neglected in this domain
Linking working memory and long-term memory: A computational model of the learning of new words
The nonword repetition (NWR) test has been shown to be a good predictor of childrenâs vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of childrenâs vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The modelâs behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity.
Keywords: EPAM, working memory, long-term memory, nonword repetition, vocabulary acquisition, developmental change
Geometric scaling in high-energy QCD at nonzero momentum transfer
We show how one can obtain geometric scaling properties from the
Balitsky-Kovchegov (BK) equation. We start by explaining how, this property
arises for the b-independent BK equation. We show that it is possible to extend
this model to the full BK equation including momentum transfer. The saturation
scale behaves like max(q,Q_T) where q is the momentum transfer and Q_T a
typical scale of the target.Comment: 4 pages, 2 figures. Talk given by G. Soyez at the "Rencontres de
Moriond", 12-19 March 2005, La Thuile, Ital
Diagnosing students' difficulties in learning mathematics
This study considers the results of a diagnostic test of student difficulty and contrasts the difference in performance between the lower attaining quartile and the higher quartile. It illustrates a difference in qualitative thinking between those who succeed and those who fail in mathematics, illustrating a theory that those who fail are performing a more difficult type of mathematics (coordinating procedures) than those who succeed (manipulating concepts). Students who have to coordinate or reverse processes in time will encounter far greater difficulty than those who can manipulate symbols in a flexible way. The consequences of such a dichotomy and implications for remediation are then considered
Size effects in statistical fracture
We review statistical theories and numerical methods employed to consider the
sample size dependence of the failure strength distribution of disordered
materials. We first overview the analytical predictions of extreme value
statistics and fiber bundle models and discuss their limitations. Next, we
review energetic and geometric approaches to fracture size effects for
specimens with a flaw. Finally, we overview the numerical simulations of
lattice models and compare with theoretical models.Comment: review article 19 pages, 5 figure
Fundamental Weights, Permutation Weights and Weyl Character Formula
For a finite Lie algebra of rank N, the Weyl orbits
of strictly dominant weights contain number of
weights where is the dimension of its Weyl group . For any
, there is a very peculiar subset for
which we always have For
any dominant weight , the elements of are called
{\bf Permutation Weights}.
It is shown that there is a one-to-one correspondence between elements of
and where is the Weyl vector of .
The concept of signature factor which enters in Weyl character formula can be
relaxed in such a way that signatures are preserved under this one-to-one
correspondence in the sense that corresponding permutation weights have the
same signature. Once the permutation weights and their signatures are specified
for a dominant , calculation of the character for
irreducible representation will then be provided by
multiplicity rules governing generalized Schur functions. The main idea is
again to express everything in terms of the so-called {\bf Fundamental Weights}
with which we obtain a quite relevant specialization in applications of Weyl
character formula.Comment: 6 pages, no figures, TeX, as will appear in Journal of Physics
A:Mathematical and Genera
Justifications-on-demand as a device to promote shifts of attention associated with relational thinking in elementary arithmetic
Student responses to arithmetical questions that can be solved by using arithmetical structure can serve to reveal the extent and nature of relational, as opposed to computational thinking. Here, student responses to probes which require them to justify-on-demand are analysed using a conceptual framework which highlights distinctions between different forms of attention. We analyse a number of actions observed in students in terms of forms of attention and shifts between them: in the short-term (in the moment), medium-term (over several tasks), and long-term (over a year). The main factors conditioning studentsÂŽ attention and its movement are identified and some didactical consequences are proposed
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