4,441 research outputs found
Questioning and responding in Italian
Questions are design problems for both the questioner and the addressee. They must be produced as recognizable objects and must be comprehended by taking into account the context in which they occur and the local situated interests of the participants. This paper investigates how people do âquestioningâ and ârespondingâ in Italian ordinary conversations. I focus on the features of both questions and responses. I first discuss formal linguistic features that are peculiar to questions in terms of intonation contours (e.g. final rise), morphology (e.g. tags and question words) and syntax (e.g. inversion). I then show additional features that characterize their actual implementation in conversation such as their minimality (often the subject or the verb is only implied) and the usual occurrence of speaker gaze towards the recipient during questions. I then look at which social actions (e.g. requests for information, requests for confirmation) the different question types implement and which responses are regularly produced in return. The data shows that previous descriptions of âinterrogative markingsâ are neither adequate nor sufficient to comprehend the actual use of questions in natural conversation
Conformal group with two observer independent scales
The Poincar\'e sector of a recently deformed conformal algebra is proposed to
describe, after the identification of the deformation parameter with the Planck
length, the symmetries of a new relativistic theory with two
observer-independent scales (or DSR theory). Also a new non-commutative
space-time is proposed. It is found that momentum space exhibits the same
features of the DSR proposals preserving Lorentz invariance in a deformed way.
The space-time sector is a generalization of the well known non-commutative
-Minkowski space-time which however does not preserve Lorentz
invariance, not even in the deformed sense. It is shown that this behavior
could be expected in some attempts to construct DSR theories starting from the
Poincar\'e sector of a deformed symmetry larger than Poincar\'e symmetry,
unless one takes a variable Planck length. It is also shown that the formalism
can be useful in analyzing the role of quantum deformations in the ``AdS-CFT
correspondence".Comment: 3 pages, brief summary of a talk given at the Tenth Marcel Grossmann
Meeting, Rio de Janeiro, 2003, based on results previously obtained in
hep-th/0306089 and hep-th/030503
Valuing Coupon Bond Linked to Variable Interest Rate
The paper analyses coupon bonds linked to variable interest rate in a contingent claim approach such that it can be decomposed in elementary options on interest rate and options to default. It is considered the case of continuous arithmetic average of interest rate in a simple capitalization to value the variable coupon paid by the bonds at maturity. The paper determines the expected interest rate on the bonds and the risk spread due to the default risk.Contingent claim, Asian option, Stochastic continuous process
Handling Massive N-Gram Datasets Efficiently
This paper deals with the two fundamental problems concerning the handling of
large n-gram language models: indexing, that is compressing the n-gram strings
and associated satellite data without compromising their retrieval speed; and
estimation, that is computing the probability distribution of the strings from
a large textual source. Regarding the problem of indexing, we describe
compressed, exact and lossless data structures that achieve, at the same time,
high space reductions and no time degradation with respect to state-of-the-art
solutions and related software packages. In particular, we present a compressed
trie data structure in which each word following a context of fixed length k,
i.e., its preceding k words, is encoded as an integer whose value is
proportional to the number of words that follow such context. Since the number
of words following a given context is typically very small in natural
languages, we lower the space of representation to compression levels that were
never achieved before. Despite the significant savings in space, our technique
introduces a negligible penalty at query time. Regarding the problem of
estimation, we present a novel algorithm for estimating modified Kneser-Ney
language models, that have emerged as the de-facto choice for language modeling
in both academia and industry, thanks to their relatively low perplexity
performance. Estimating such models from large textual sources poses the
challenge of devising algorithms that make a parsimonious use of the disk. The
state-of-the-art algorithm uses three sorting steps in external memory: we show
an improved construction that requires only one sorting step thanks to
exploiting the properties of the extracted n-gram strings. With an extensive
experimental analysis performed on billions of n-grams, we show an average
improvement of 4.5X on the total running time of the state-of-the-art approach.Comment: Published in ACM Transactions on Information Systems (TOIS), February
2019, Article No: 2
On Optimally Partitioning Variable-Byte Codes
The ubiquitous Variable-Byte encoding is one of the fastest compressed
representation for integer sequences. However, its compression ratio is usually
not competitive with other more sophisticated encoders, especially when the
integers to be compressed are small that is the typical case for inverted
indexes. This paper shows that the compression ratio of Variable-Byte can be
improved by 2x by adopting a partitioned representation of the inverted lists.
This makes Variable-Byte surprisingly competitive in space with the best
bit-aligned encoders, hence disproving the folklore belief that Variable-Byte
is space-inefficient for inverted index compression. Despite the significant
space savings, we show that our optimization almost comes for free, given that:
we introduce an optimal partitioning algorithm that does not affect indexing
time because of its linear-time complexity; we show that the query processing
speed of Variable-Byte is preserved, with an extensive experimental analysis
and comparison with several other state-of-the-art encoders.Comment: Published in IEEE Transactions on Knowledge and Data Engineering
(TKDE), 15 April 201
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