188,449 research outputs found
Cross-Lingual Adaptation using Structural Correspondence Learning
Cross-lingual adaptation, a special case of domain adaptation, refers to the
transfer of classification knowledge between two languages. In this article we
describe an extension of Structural Correspondence Learning (SCL), a recently
proposed algorithm for domain adaptation, for cross-lingual adaptation. The
proposed method uses unlabeled documents from both languages, along with a word
translation oracle, to induce cross-lingual feature correspondences. From these
correspondences a cross-lingual representation is created that enables the
transfer of classification knowledge from the source to the target language.
The main advantages of this approach over other approaches are its resource
efficiency and task specificity.
We conduct experiments in the area of cross-language topic and sentiment
classification involving English as source language and German, French, and
Japanese as target languages. The results show a significant improvement of the
proposed method over a machine translation baseline, reducing the relative
error due to cross-lingual adaptation by an average of 30% (topic
classification) and 59% (sentiment classification). We further report on
empirical analyses that reveal insights into the use of unlabeled data, the
sensitivity with respect to important hyperparameters, and the nature of the
induced cross-lingual correspondences
Structural Subtyping as Parametric Polymorphism
Structural subtyping and parametric polymorphism provide similar flexibility
and reusability to programmers. For example, both features enable the
programmer to provide a wider record as an argument to a function that expects
a narrower one. However, the means by which they do so differs substantially,
and the precise details of the relationship between them exists, at best, as
folklore in literature.
In this paper, we systematically study the relative expressive power of
structural subtyping and parametric polymorphism. We focus our investigation on
establishing the extent to which parametric polymorphism, in the form of row
and presence polymorphism, can encode structural subtyping for variant and
record types. We base our study on various Church-style -calculi
extended with records and variants, different forms of structural subtyping,
and row and presence polymorphism.
We characterise expressiveness by exhibiting compositional translations
between calculi. For each translation we prove a type preservation and
operational correspondence result. We also prove a number of non-existence
results. By imposing restrictions on both source and target types, we reveal
further subtleties in the expressiveness landscape, the restrictions enabling
otherwise impossible translations to be defined. More specifically, we prove
that full subtyping cannot be encoded via polymorphism, but we show that
several restricted forms of subtyping can be encoded via particular forms of
polymorphism.Comment: 47 pages, accepted by OOPSLA 202
A decompilation of the pi-calculus and its application to termination
We study the correspondence between a concurrent lambda-calculus in
administrative, continuation passing style and a pi-calculus and we derive a
termination result for the latter
Non normal logics: semantic analysis and proof theory
We introduce proper display calculi for basic monotonic modal logic,the
conditional logic CK and a number of their axiomatic extensions. These calculi
are sound, complete, conservative and enjoy cut elimination and subformula
property. Our proposal applies the multi-type methodology in the design of
display calculi, starting from a semantic analysis based on the translation
from monotonic modal logic to normal bi-modal logic
Session Types as Generic Process Types
Behavioural type systems ensure more than the usual safety guarantees of
static analysis. They are based on the idea of "types-as-processes", providing
dedicated type algebras for particular properties, ranging from protocol
compatibility to race-freedom, lock-freedom, or even responsiveness. Two
successful, although rather different, approaches, are session types and
process types. The former allows to specify and verify (distributed)
communication protocols using specific type (proof) systems; the latter allows
to infer from a system specification a process abstraction on which it is
simpler to verify properties, using a generic type (proof) system. What is the
relationship between these approaches? Can the generic one subsume the specific
one? At what price? And can the former be used as a compiler for the latter?
The work presented herein is a step towards answers to such questions.
Concretely, we define a stepwise encoding of a pi-calculus with sessions and
session types (the system of Gay and Hole) into a pi-calculus with process
types (the Generic Type System of Igarashi and Kobayashi). We encode session
type environments, polarities (which distinguish session channels end-points),
and labelled sums. We show forward and reverse operational correspondences for
the encodings, as well as typing correspondences. To faithfully encode session
subtyping in process types subtyping, one needs to add to the target language
record constructors and new subtyping rules. In conclusion, the programming
convenience of session types as protocol abstractions can be combined with the
simplicity and power of the pi-calculus, taking advantage in particular of the
framework provided by the Generic Type System.Comment: In Proceedings EXPRESS/SOS 2014, arXiv:1408.127
On the Expressiveness of Intensional Communication
The expressiveness of communication primitives has been explored in a common
framework based on the pi-calculus by considering four features: synchronism
(asynchronous vs synchronous), arity (monadic vs polyadic data), communication
medium (shared dataspaces vs channel-based), and pattern-matching (binding to a
name vs testing name equality). Here pattern-matching is generalised to account
for terms with internal structure such as in recent calculi like Spi calculi,
Concurrent Pattern Calculus and Psi calculi. This paper explores intensionality
upon terms, in particular communication primitives that can match upon both
names and structures. By means of possibility/impossibility of encodings, this
paper shows that intensionality alone can encode synchronism, arity,
communication-medium, and pattern-matching, yet no combination of these without
intensionality can encode any intensional language.Comment: In Proceedings EXPRESS/SOS 2014, arXiv:1408.127
Peaks detection and alignment for mass spectrometry data
The goal of this paper is to review existing methods for protein mass spectrometry data analysis, and to present a new methodology for automatic extraction of significant peaks (biomarkers). For the pre-processing step required for data from MALDI-TOF or SELDI- TOF spectra, we use a purely nonparametric approach that combines stationary invariant wavelet transform for noise removal and penalized spline quantile regression for baseline correction. We further present a multi-scale spectra alignment technique that is based on identification of statistically significant peaks from a set of spectra. This method allows one to find common peaks in a set of spectra that can subsequently be mapped to individual proteins. This may serve as useful biomarkers in medical applications, or as individual features for further multidimensional statistical analysis. MALDI-TOF spectra obtained from serum samples are used throughout the paper to illustrate the methodology
Categories without structures
The popular view according to which Category theory provides a support for
Mathematical Structuralism is erroneous. Category-theoretic foundations of
mathematics require a different philosophy of mathematics. While structural
mathematics studies invariant forms (Awodey) categorical mathematics studies
covariant transformations which, generally, don t have any invariants. In this
paper I develop a non-structuralist interpretation of categorical mathematics
and show its consequences for history of mathematics and mathematics education.Comment: 28 page
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