3,557 research outputs found
Thematic Annotation: extracting concepts out of documents
Contrarily to standard approaches to topic annotation, the technique used in
this work does not centrally rely on some sort of -- possibly statistical --
keyword extraction. In fact, the proposed annotation algorithm uses a large
scale semantic database -- the EDR Electronic Dictionary -- that provides a
concept hierarchy based on hyponym and hypernym relations. This concept
hierarchy is used to generate a synthetic representation of the document by
aggregating the words present in topically homogeneous document segments into a
set of concepts best preserving the document's content.
This new extraction technique uses an unexplored approach to topic selection.
Instead of using semantic similarity measures based on a semantic resource, the
later is processed to extract the part of the conceptual hierarchy relevant to
the document content. Then this conceptual hierarchy is searched to extract the
most relevant set of concepts to represent the topics discussed in the
document. Notice that this algorithm is able to extract generic concepts that
are not directly present in the document.Comment: Technical report EPFL/LIA. 81 pages, 16 figure
The unemployment challenge : Labour market policies for the recession
Over the next year another 50,000 people will become unemployed. The number of unemployed will surpass that of the last recession of 1997-98. To address the unemployment challenge New Zealand needs to supplement existing job search assistance with investment in training and business capital to push long term productivity growth. Subsidies to prop up jobs and firms should be avoided. The April 2009 QSBO found that a net 36% of firms intend to cut staff numbers in the next three months. Unemployment will be the worst we have faced since the 1991 global recession. With the peak in unemployment approaching, attention needs to shift now to the challenge of getting the unemployed into work. The temptation will be to artificially protect jobs. But this is short-sighted. The economic imperative should be to ensure New Zealand has the right human capital to prosper when the economy picks up. At first glance, recent initiatives (temporary top-up support for those made redundant and the 9 day fortnight) appear sensible. But they have downsides and should be removed after the crisis has passed. Also, because they are tightly targeted they will have little impact, and do not cater well for many of the 50,000 or so extra unemployed. These will be new entrants to the labour market or those employed by small firms. This policy gap needs to be filled to avoid high and long-term unemployment.Recession, unemployment, New Zealand
The Extended Algebra of the SU(2) Wess-Zumino-Witten Models
The Wess-Zumino-Witten model defined on the group SU(2) has a unique
(non-trivial) simple current of conformal dimension k/4 for each level k. The
extended algebra defined by this simple current is carefully constructed in
terms of generalised commutation relations, and the corresponding
representation theory is investigated. This extended algebra approach is proven
to realise a faithful ("free-field-type") representation of the SU(2) model.
Subtleties in the formulation of the extended theory are illustrated throughout
by the k=1, 2 and 4 models. For the first two cases, bases for the modules of
the extended theory are given and rigorously justified.Comment: 42 pages, 2 figures; added further motivational material and
corrected typo
Editorial special issue: PHM for railway systems and mass transportation
The railway and mass transportation system is composed of industrial goods with substantial capital investments and long life cycles. This applies to rolling stock like trains, locomotives, wagons, and even more to the infrastructure like signaling, catenary, tracks, bridges, and tunnels. The lifespan of rolling stock is 30 to 40 years while the infrastructure is used 30 to 60 years even more than 100 years in case of tunnels and bridges. As in other industrial goods, the cost drivers are determined in the early design phases but realized mainly during a long time of operation. Maintenance is one of the main cost drivers but essential to a reliable, capable, and – above all – safe operation
Chemical spray pyrolysis of Tl-Ba-Ca-Cu-O high-T(sub c) superconductors for high-field bitter magnets
The deposition of Tl-Ba-Ca-Cu-O thick films by spray pyrolyzing a Ba-Ca-Cu-O precursor film and diffusing thallium into the film to form the superconducting phase is examined. This approach was taken to reduce exposure to thallium and its health and safety hazards. The Tl-Ba-Ca-Cu-O system was selected because it has very attractive features which make it appealing to device and manufacturing engineering. Tl-Ba-Ca-Cu-O will accommodate a number of superconducting phases. This attribute makes it very forgiving to stoichiometric fluctuations in the bulk and film. It has excellent thermal and chemical stability, and appears to be relatively insensitive to chemical impurities. Oxygen is tightly bound into the systems, consequently there is no orthorhombic (conductor) to tetragonal (insulator) transition which would affect a component's lifetime. More significantly, the thallium based superconductors appear to have harder magnetic properties than the other high-Tc oxide ceramics. Estimates using magnetoresistance measurements indicate that at 77 K Tl2Ba2CaCu2O10 will have an upper critical field, H(sub c2) fo 26 Tesla for applied fields parallel to the c-axis and approximately 1000 Tesla for fields oriented in the a-b plane. Results to date have shown that superconducting films can be reproducibly deposited on 100 oriented MgO substrates. One film had a zero resistance temperature of 111.5 K. Furthermore, x ray diffraction analysis of the films showed preferential c-axis orientation parallel to the plane of the substrate. These results have now made it possible to consider the manufacture of a superconducting tape wire which can be configured into a topology useful for high-field magnet designs. The research which leads to the preparation of these films and plans for further development are reviewed
DISI -Via Sommarive 14 -38123 Povo
Abstract Handling everyday tasks such as search, classification and integration is becoming increasingly difficult and sometimes even impossible due to the increasing streams of data available. To overcome such an information overload we need more accurate information processing tools capable of handling big amounts of data. In particular, handling metadata can give us leverage over the data and enable structured processing of data, however, while some of this metadata is in a computer readable format, some of it is manually created in ambiguous natural language. Thus, accessing the semantics of natural language can increase the quality of information processing. We propose a natural language metadata understanding architecture that enables applications such as semantic matching, classification and search based on natural language metadata by providing a translation into a formal language which outperforms the state of the art by 15%
Gender-specific Machine Translation with Large Language Models
Decoder-only Large Language Models (LLMs) have demonstrated potential in
machine translation (MT), albeit with performance slightly lagging behind
traditional encoder-decoder Neural Machine Translation (NMT) systems. However,
LLMs offer a unique advantage: the ability to control the properties of the
output through prompts. In this study, we harness this flexibility to explore
LLaMa's capability to produce gender-specific translations for languages with
grammatical gender. Our results indicate that LLaMa can generate
gender-specific translations with competitive accuracy and gender bias
mitigation when compared to NLLB, a state-of-the-art multilingual NMT system.
Furthermore, our experiments reveal that LLaMa's translations are robust,
showing significant performance drops when evaluated against opposite-gender
references in gender-ambiguous datasets but maintaining consistency in less
ambiguous contexts. This research provides insights into the potential and
challenges of using LLMs for gender-specific translations and highlights the
importance of in-context learning to elicit new tasks in LLMs
Jack superpolynomials with negative fractional parameter: clustering properties and super-Virasoro ideals
The Jack polynomials P_\lambda^{(\alpha)} at \alpha=-(k+1)/(r-1) indexed by
certain (k,r,N)-admissible partitions are known to span an ideal I^{(k,r)}_N of
the space of symmetric functions in N variables. The ideal I^{(k,r)}_N is
invariant under the action of certain differential operators which include half
the Virasoro algebra. Moreover, the Jack polynomials in I^{(k,r)}_N admit
clusters of size at most k: they vanish when k+1 of their variables are
identified, and they do not vanish when only k of them are identified. We
generalize most of these properties to superspace using orthogonal
eigenfunctions of the supersymmetric extension of the trigonometric
Calogero-Moser-Sutherland model known as Jack superpolynomials. In particular,
we show that the Jack superpolynomials P_{\Lambda}^{(\alpha)} at
\alpha=-(k+1)/(r-1) indexed by certain (k,r,N)-admissible superpartitions span
an ideal {\mathcal I}^{(k,r)}_N of the space of symmetric polynomials in N
commuting variables and N anticommuting variables. We prove that the ideal
{\mathcal I}^{(k,r)}_N is stable with respect to the action of the
negative-half of the super-Virasoro algebra. In addition, we show that the Jack
superpolynomials in {\mathcal I}^{(k,r)}_N vanish when k+1 of their commuting
variables are equal, and conjecture that they do not vanish when only k of them
are identified. This allows us to conclude that the standard Jack polynomials
with prescribed symmetry should satisfy similar clustering properties. Finally,
we conjecture that the elements of {\mathcal I}^{(k,2)}_N provide a basis for
the subspace of symmetric superpolynomials in N variables that vanish when k+1
commuting variables are set equal to each other.Comment: 36 pages; the main changes in v2 are : 1) in the introduction, we
present exceptions to an often made statement concerning the clustering
property of the ordinary Jack polynomials for (k,r,N)-admissible partitions
(see Footnote 2); 2) Conjecture 14 is substantiated with the extensive
computational evidence presented in the new appendix C; 3) the various tests
supporting Conjecture 16 are reporte
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