167,718 research outputs found
Solving General Arithmetic Word Problems
This paper presents a novel approach to automatically solving arithmetic word
problems. This is the first algorithmic approach that can handle arithmetic
problems with multiple steps and operations, without depending on additional
annotations or predefined templates. We develop a theory for expression trees
that can be used to represent and evaluate the target arithmetic expressions;
we use it to uniquely decompose the target arithmetic problem to multiple
classification problems; we then compose an expression tree, combining these
with world knowledge through a constrained inference framework. Our classifiers
gain from the use of {\em quantity schemas} that supports better extraction of
features. Experimental results show that our method outperforms existing
systems, achieving state of the art performance on benchmark datasets of
arithmetic word problems.Comment: EMNLP 201
Phloem cytochemical modification and gene expression following the recovery of apple plants from apple proliferation
Recovery of apple trees from apple proliferation was studied by
combining ultrastructural, cytochemical, and gene expression analyses to
possibly reveal changes linked to recovery-associated resistance. When
compared with either healthy or visibly diseased plants, recovered apple
trees showed abnormal callose and phloem-protein accumulation in their
leaf phloem. Although cytochemical localization detected Ca2+ ions in the
phloem of all the three plant groups, Ca2+ concentration was remarkably
higher in the phloem cytosol of recovered trees. The expression patterns
of five genes encoding callose synthase and of four genes encoding
phloem proteins were analyzed by quantitative real-time reverse transcription-
polymerase chain reaction. In comparison to both healthy and
diseased plants, four of the above nine genes were remarkably upregulated
in recovered trees. As in infected apple trees, phytoplasma
disappear from the crown during winter, but persist in the roots, and it is
suggested that callose synthesis/deposition and phloem-protein plugging
of the sieve tubes would form physical barriers preventing the recolonization
of the crown during the following spring. Since callose deposition
and phloem-protein aggregation are both Ca2+-dependent processes, the
present results suggest that an inward flux of Ca2+ across the phloem
plasma membrane could act as a signal for activating defense reactions
leading to recovery in phytoplasma-infected apple trees.L'articolo Ă© disponibile sul sito dell'editore: http://www.apsjournals.apsnet.or
A Comparison of Well-Quasi Orders on Trees
Well-quasi orders such as homeomorphic embedding are commonly used to ensure
termination of program analysis and program transformation, in particular
supercompilation.
We compare eight well-quasi orders on how discriminative they are and their
computational complexity. The studied well-quasi orders comprise two very
simple examples, two examples from literature on supercompilation and four new
proposed by the author.
We also discuss combining several well-quasi orders to get well-quasi orders
of higher discriminative power. This adds 19 more well-quasi orders to the
list.Comment: In Proceedings Festschrift for Dave Schmidt, arXiv:1309.455
Lie algebra configuration pairing
We give an algebraic construction of the topological graph-tree configuration
pairing of Sinha and Walter beginning with the classical presentation of Lie
coalgebras via coefficients of words in the associative Lie polynomial. Our
work moves from associative algebras to preLie algebras to graph complexes,
justifying the use of graph generators for Lie coalgebras by iteratively
expanding the set of generators until the set of relations collapses to two
simple local expressions. Our focus is on new computational methods allowed by
this framework and the efficiency of the graph presentation in proofs and
calculus involving free Lie algebras and coalgebras. This outlines a new way of
understanding and calculating with Lie algebras arising from the graph
presentation of Lie coalgebras.Comment: 21 pages; uses xypic; ver 4. added subsection 3.4 outlining another
computational algorithm arising from configuration pairing with graph
Individual and Domain Adaptation in Sentence Planning for Dialogue
One of the biggest challenges in the development and deployment of spoken
dialogue systems is the design of the spoken language generation module. This
challenge arises from the need for the generator to adapt to many features of
the dialogue domain, user population, and dialogue context. A promising
approach is trainable generation, which uses general-purpose linguistic
knowledge that is automatically adapted to the features of interest, such as
the application domain, individual user, or user group. In this paper we
present and evaluate a trainable sentence planner for providing restaurant
information in the MATCH dialogue system. We show that trainable sentence
planning can produce complex information presentations whose quality is
comparable to the output of a template-based generator tuned to this domain. We
also show that our method easily supports adapting the sentence planner to
individuals, and that the individualized sentence planners generally perform
better than models trained and tested on a population of individuals. Previous
work has documented and utilized individual preferences for content selection,
but to our knowledge, these results provide the first demonstration of
individual preferences for sentence planning operations, affecting the content
order, discourse structure and sentence structure of system responses. Finally,
we evaluate the contribution of different feature sets, and show that, in our
application, n-gram features often do as well as features based on higher-level
linguistic representations
Generating trees for permutations avoiding generalized patterns
We construct generating trees with one, two, and three labels for some
classes of permutations avoiding generalized patterns of length 3 and 4. These
trees are built by adding at each level an entry to the right end of the
permutation, which allows us to incorporate the adjacency condition about some
entries in an occurrence of a generalized pattern. We use these trees to find
functional equations for the generating functions enumerating these classes of
permutations with respect to different parameters. In several cases we solve
them using the kernel method and some ideas of Bousquet-M\'elou. We obtain
refinements of known enumerative results and find new ones.Comment: 17 pages, to appear in Ann. Com
Mayer expansion of the Nekrasov pre potential: the subleading -order
The Mayer cluster expansion technique is applied to the Nekrasov instanton
partition function of super Yang-Mills. The
subleading small -correction to the Nekrasov-Shatashvili limiting
value of the prepotential is determined by a detailed analysis of all the
one-loop diagrams. Indeed, several types of contributions can be distinguished
according to their origin: long range interaction or potential expansion,
clusters self-energy, internal structure, one-loop cyclic diagrams, etc.. The
field theory result derived more efficiently in [1], under some minor technical
assumptions, receives here definite confirmation thanks to several remarkable
cancellations: in this way, we may infer the validity of these assumptions for
further computations in the field theoretical approach.Comment: 29 pages, 9 figure
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