2,447 research outputs found
A Data-Oriented Approach to Semantic Interpretation
In Data-Oriented Parsing (DOP), an annotated language corpus is used as a
stochastic grammar. The most probable analysis of a new input sentence is
constructed by combining sub-analyses from the corpus in the most probable way.
This approach has been succesfully used for syntactic analysis, using corpora
with syntactic annotations such as the Penn Treebank. If a corpus with
semantically annotated sentences is used, the same approach can also generate
the most probable semantic interpretation of an input sentence. The present
paper explains this semantic interpretation method, and summarizes the results
of a preliminary experiment. Semantic annotations were added to the syntactic
annotations of most of the sentences of the ATIS corpus. A data-oriented
semantic interpretation algorithm was succesfully tested on this semantically
enriched corpus.Comment: 10 pages, Postscript; to appear in Proceedings Workshop on
Corpus-Oriented Semantic Analysis, ECAI-96, Budapes
Membrane formation by immersion precipitation : the role of a polymeric additive
In this thesis the immersion precipitation process is studied for systems in which two polymers are present.\ud
In its basic form, immersion precipitation is carried out by immersing a thin film of a concentrated polymer solution into a bath of nonsolvent. By exchange of solvent from the polymer solution, and nonsolvent from the coagulation bath, the polymer solution becomes instable. Liquid-liquid phase separation results in a polymer lean phase and a polymer rich phase. The polymer lean phase forms pores inside a matrix created by the polymer rich phase, which forms the membrane.\ud
The objective of this thesis is to investigate the effects of the addition of a second polymer into the polymer solution. The use of a second polymer (polymeric additive) that is miscible with the nonsolvent can result in more open porous (co-continuous) structures and a better defined porosity
Data-Oriented Language Processing. An Overview
During the last few years, a new approach to language processing has started
to emerge, which has become known under various labels such as "data-oriented
parsing", "corpus-based interpretation", and "tree-bank grammar" (cf. van den
Berg et al. 1994; Bod 1992-96; Bod et al. 1996a/b; Bonnema 1996; Charniak
1996a/b; Goodman 1996; Kaplan 1996; Rajman 1995a/b; Scha 1990-92; Sekine &
Grishman 1995; Sima'an et al. 1994; Sima'an 1995-96; Tugwell 1995). This
approach, which we will call "data-oriented processing" or "DOP", embodies the
assumption that human language perception and production works with
representations of concrete past language experiences, rather than with
abstract linguistic rules. The models that instantiate this approach therefore
maintain large corpora of linguistic representations of previously occurring
utterances. When processing a new input utterance, analyses of this utterance
are constructed by combining fragments from the corpus; the
occurrence-frequencies of the fragments are used to estimate which analysis is
the most probable one.
In this paper we give an in-depth discussion of a data-oriented processing
model which employs a corpus of labelled phrase-structure trees. Then we review
some other models that instantiate the DOP approach. Many of these models also
employ labelled phrase-structure trees, but use different criteria for
extracting fragments from the corpus or employ different disambiguation
strategies (Bod 1996b; Charniak 1996a/b; Goodman 1996; Rajman 1995a/b; Sekine &
Grishman 1995; Sima'an 1995-96); other models use richer formalisms for their
corpus annotations (van den Berg et al. 1994; Bod et al., 1996a/b; Bonnema
1996; Kaplan 1996; Tugwell 1995).Comment: 34 pages, Postscrip
A Delta Debugger for ILP Query Execution
Because query execution is the most crucial part of Inductive Logic
Programming (ILP) algorithms, a lot of effort is invested in developing faster
execution mechanisms. These execution mechanisms typically have a low-level
implementation, making them hard to debug. Moreover, other factors such as the
complexity of the problems handled by ILP algorithms and size of the code base
of ILP data mining systems make debugging at this level a very difficult job.
In this work, we present the trace-based debugging approach currently used in
the development of new execution mechanisms in hipP, the engine underlying the
ACE Data Mining system. This debugger uses the delta debugging algorithm to
automatically reduce the total time needed to expose bugs in ILP execution,
thus making manual debugging step much lighter.Comment: Paper presented at the 16th Workshop on Logic-based Methods in
Programming Environments (WLPE2006
Thermoforming of foam sheet
Thermoforming is a widely used process for the manufacture of foam sheet products. Polystyrene foam food trays for instance can be produced by first heating the thermoplastic foam sheet, causing the gas contained to build up pressure and expand, after which a vacuum pressure can be applied to draw the sheet in the required form on the mould. This production method appears to be a very sensitive process with respect to e.g. the sheet temperature, the pressures applied and the cooling time. More problems can be foreseen when for environmental reasons the blowing agent will be adapted (for instance replaced by a gas with a lower molecular weight). To gain more insight in the occuring phenomena the large deformations of a foam structure have been analysed using finite element modelling. To this end a constitutive model has to be defined. Starting from the basic theory given by Gibson & Ashby [1], the behaviour of a closed cubic cell has been elaborated for large strains. The total stiffness is then the sum of the contributions of the edges and faces of the cell and the gas contained in it. The large deformations cause anisotropy of the cells [2], which influences their tangential stiffness. The constitutive model developed here includes the effects of internal gas pressure and the evolving anisotropy
Galileons as the Scalar Analogue of General Relativity
We establish a correspondence between general relativity with diffeomorphism
invariance and scalar field theories with Galilean invariance: notions such as
the Levi-Civita connection and the Riemann tensor have a Galilean counterpart.
This suggests Galilean theories as the unique nontrivial alternative to gauge
theories (including general relativity). Moreover, it is shown that the
requirement of first-order Palatini formalism uniquely determines the Galileon
models with second-order field equations, similar to the Lovelock gravity
theories. Possible extensions are discussed.Comment: 6 pages, v2: Version appeared in Phys. Rev.
Higher Derivative Field Theories: Degeneracy Conditions and Classes
We provide a full analysis of ghost free higher derivative field theories
with coupled degrees of freedom. Assuming the absence of gauge symmetries, we
derive the degeneracy conditions in order to evade the Ostrogradsky ghosts, and
analyze which (non)trivial classes of solutions this allows for. It is shown
explicitly how Lorentz invariance avoids the propagation of "half" degrees of
freedom. Moreover, for a large class of theories, we construct the field
redefinitions and/or (extended) contact transformations that put the theory in
a manifestly first order form. Finally, we identify which class of theories
cannot be brought to first order form by such transformations.Comment: 26 pages, 1 figure. v2: minor changes, references added, matches
version published in JHE
Sketching is more than making correct drawings
Sketching in the context of a design process is not a goal in itself, but can be considered as a tool to\ud
make better designs. Sketching as a design tool has several useful effects as: ordering your thoughts,\ud
better understanding of difficult shapes, functioning as a communication tool, and providing an\ud
iterative way of developing shapes. In our bachelor-curriculum Industrial Design Engineering we\ud
developed a series of courses that addresses these effects in particular.\ud
The courses are Sketching and concept drawing (SCT), Product Presentation Drawing (PPT) and\ud
Applied sketching skills (TTV). This line of courses is built on three pillars:\ud
- Learning to sketch; Theory, speed and control of the materials.\ud
- Learning from sketching; Develop a better insight in complex 3D shapes (Figure 1).\ud
- Sketching as a design tool; Communication, ordering your thoughts, iterative working.\ud
As a result we see that students who have finished the courses instinctively start sketching in an\ud
iterative manner, use sketching as a source of inspiration and learn that the whole process of iterative\ud
sketching helps in structuring, developing and communicating the design process. In this way the\ud
students become better sketchers and better designer
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