119,352 research outputs found
Towards an Indexical Model of Situated Language Comprehension for Cognitive Agents in Physical Worlds
We propose a computational model of situated language comprehension based on
the Indexical Hypothesis that generates meaning representations by translating
amodal linguistic symbols to modal representations of beliefs, knowledge, and
experience external to the linguistic system. This Indexical Model incorporates
multiple information sources, including perceptions, domain knowledge, and
short-term and long-term experiences during comprehension. We show that
exploiting diverse information sources can alleviate ambiguities that arise
from contextual use of underspecific referring expressions and unexpressed
argument alternations of verbs. The model is being used to support linguistic
interactions in Rosie, an agent implemented in Soar that learns from
instruction.Comment: Advances in Cognitive Systems 3 (2014
Robust Processing of Natural Language
Previous approaches to robustness in natural language processing usually
treat deviant input by relaxing grammatical constraints whenever a successful
analysis cannot be provided by ``normal'' means. This schema implies, that
error detection always comes prior to error handling, a behaviour which hardly
can compete with its human model, where many erroneous situations are treated
without even noticing them.
The paper analyses the necessary preconditions for achieving a higher degree
of robustness in natural language processing and suggests a quite different
approach based on a procedure for structural disambiguation. It not only offers
the possibility to cope with robustness issues in a more natural way but
eventually might be suited to accommodate quite different aspects of robust
behaviour within a single framework.Comment: 16 pages, LaTeX, uses pstricks.sty, pstricks.tex, pstricks.pro,
pst-node.sty, pst-node.tex, pst-node.pro. To appear in: Proc. KI-95, 19th
German Conference on Artificial Intelligence, Bielefeld (Germany), Lecture
Notes in Computer Science, Springer 199
The price of inscrutability
In our reasoning we depend on the stability of language, the fact that its signs do not arbitrarily change in meaning from moment to moment.(Campbell, 1994, p.82)
Some philosophers offer arguments contending that ordinary names such as âLondonâ are radically indeterminate in reference. The conclusion of such arguments is that there is no fact of the matter whether âLondonâ refers to a city in the south of England, or whether instead it refers to
Sydney, Australia. Some philosophers have even suggested that we accept the conclusion of these arguments.
Such a position seems crazy to many; but what exactly goes wrong if one adopts such a view? This paper evaluates the theoretical costs incurred by one who endorses extreme inscrutability of reference (the âinscrutabilistâ). I show that there is one particular implication of extreme
inscrutability which pushes the price of inscrutabilism too high. An extension of the classic âpermutationâ arguments for extreme inscrutability allow us to establish what I dub âextreme indexical inscrutabilityâ. This result, I argue, unacceptably undermines the epistemology of inference.
The first half of the paper develops the background of permutation arguments for extreme inscrutability
of reference and evaluates some initial attempts to make trouble for the inscrutabilist.
Sections 1 and 2 describe the setting of the original permutation arguments for extreme inscrutability.
Sections 3 and 4 survey four potential objections to extreme inscrutability of reference,
including some recently raised in Vann McGeeâs excellent (2005a). Sections 5 sketches how the permutation arguments can be generalized to establish extreme indexical inscrutability; and shows how this contradicts a âstability principleââthat our words do not arbitrarily
change their reference from one moment to the nextâwhich I claim plays a vital role in the epistemology of inference.
The second half of the paper develops in detail the case for thinking that language is stable
in the relevant sense. In section 6, I use this distinction to call into question the epistemological
relevance of validity of argument types; Kaplanâs treatment of indexical validity partially resolves this worry, but there is a residual problem. In section 7, I argue that stability is exactly what is needed to bridge this final gap, and so secure the relevance of validity to good inferential practice. Section 8 responds to objections to this claim.
An appendix to the paper provides formal backing for the results cited in this paper, including a generalization of permutation arguments to the kind of rich setting required for a realistic semantics of natural language.1 Extreme indexical inscrutability results can be proved within
this setting. The first half of the paper shows that the inscrutabilist is committed to extreme indexical inscrutability, which implies that language not determinately âstableâ. The second half of the paper argues that good inference requires stability. The price of inscrutabilism, therefore, is to sever the connection between the validity of argument-forms and inferential practice: and this is too high a price to pay
Gavagai again
Quine (1960, ch.2) claims that there are a variety of equally good schemes for translating or interpreting ordinary talk. âRabbitâ might be taken to divide its reference over rabbits, over temporal slices of rabbits, or undetached parts of rabbits, without significantly affecting which sentences get classified as true and which as false. This is the basis of his famous âargument from belowâ to the conclusion that there can be no fact of the matter as to how reference is to be divided. Putative counterexamples to Quineâs claim have been put forward in the past (see especially Evans, 1975; Fodor, 1993), and various patches have been suggested (e.g. Wright, 1997). One lacuna in this literature is that one does not find any detailed presentation of what exactly these interpretations are supposed to be. Drawing on contemporary literature on persistence, the present paper sets out detailed semantic treatments for fragments of English, whereby predicates such as ârabbitâ divide their reference over four-dimensional continuants (Quineâs rabbits), instantaneous temporal slices of those continuants (Quineâs rabbit-slices) and the simple elements which compose those slices (undetached rabbit parts) respectively. Once we have the systematic interpretations on the table, we can get to work evaluating them
The Semantics and Acquisition of Time in Language
This dissertation is about the structure of temporal semantics and childrenâs acquisition of temporal language. It argues for the importance of investigating semantics both at the abstract level of linguistic structures and at the concrete level of the time-course of acquisition, as these two levels provide natural constraints for each other. With respect to semantics, it provides a computationally inspired analysis of tense, grammatical aspect and lexical aspect that uses finite state automata to dynamically calculate the progress of an event over a time interval. It is shown that the analysis can account for many well-known temporal phenomena, such as the different entailments of telic and atelic predicates in the imperfective aspect (the imperfective paradox), and the various unified and serial interpretations of sentences involving a cardinally quantified phrase, such as Three Ringlings visited Florida. With respect to childrenâs acquisition of temporal language, the dissertation investigates the Aspect First hypothesis which states that children initially use tense and grammatical aspect morphology to mark the lexical aspect property of telicity. Two forced-choice comprehension experiments were conducted with children aged 2.5 to 5 years old to test childrenâs understanding of tense and grammatical aspect morphology; in a control condition, open class cues were used to test childrenâs conceptual competence with tense and grammatical aspect information independently of their competence with the relevant morphology (e.g., in the middle of and in a few seconds were the open class cues for imperfective aspect and future tense, respectively). Results showed that even the youngest children understood the concepts underlying tense and grammatical aspect as measured by their performance with the open class cues but they did not demonstrate adult competence with the closed class morphology for grammatical aspect and did so only marginally for tense. Comprehension of tense morphology preceded that of grammatical aspect morphology and in particular, children showed an early facility with markers of the future tense
Connectionist natural language parsing
The key developments of two decades of connectionist parsing are reviewed. Connectionist parsers are assessed according to their ability to learn to represent syntactic structures from examples automatically, without being presented with symbolic grammar rules. This review also considers the extent to which connectionist parsers offer computational models of human sentence processing and provide plausible accounts of psycholinguistic data. In considering these issues, special attention is paid to the level of realism, the nature of the modularity, and the type of processing that is to be found in a wide range of parsers
Enactivism and Robotic Language Acquisition: A Report from the Frontier
In this article, I assess an existing language acquisition architecture, which was deployed in linguistically unconstrained humanârobot interaction, together with experimental design decisions with regard to their enactivist credentials. Despite initial scepticism with respect to enactivismâs applicability to the social domain, the introduction of the notion of participatory sense-making in the more recent enactive literature extends the frameworkâs reach to encompass this domain. With some exceptions, both our architecture and form of experimentation appear to be largely compatible with enactivist tenets. I analyse the architecture and design decisions along the five enactivist core themes of autonomy, embodiment, emergence, sense-making, and experience, and discuss the role of affect due to its central role within our acquisition experiments. In conclusion, I join some enactivists in demanding that interaction is taken seriously as an irreducible and independent subject of scientific investigation, and go further by hypothesising its potential value to machine learning.Peer reviewedFinal Published versio
Programming in logic without logic programming
In previous work, we proposed a logic-based framework in which computation is
the execution of actions in an attempt to make reactive rules of the form if
antecedent then consequent true in a canonical model of a logic program
determined by an initial state, sequence of events, and the resulting sequence
of subsequent states. In this model-theoretic semantics, reactive rules are the
driving force, and logic programs play only a supporting role.
In the canonical model, states, actions and other events are represented with
timestamps. But in the operational semantics, for the sake of efficiency,
timestamps are omitted and only the current state is maintained. State
transitions are performed reactively by executing actions to make the
consequents of rules true whenever the antecedents become true. This
operational semantics is sound, but incomplete. It cannot make reactive rules
true by preventing their antecedents from becoming true, or by proactively
making their consequents true before their antecedents become true.
In this paper, we characterize the notion of reactive model, and prove that
the operational semantics can generate all and only such models. In order to
focus on the main issues, we omit the logic programming component of the
framework.Comment: Under consideration in Theory and Practice of Logic Programming
(TPLP
Feature-based and Model-based Semantics for English, French and German Verb Phrases
This paper considers the relative merits of using features and formal event models to characterise the semantics of English, French and German verb phrases, and con- siders the application of such semantics in machine translation. The feature-based ap- proach represents the semantics in terms of feature systems, which have been widely used in computational linguistics for representing complex syntactic structures. The paper shows how a simple intuitive semantics of verb phrases may be encoded as a feature system, and how this can be used to support modular construction of au- tomatic translation systems through feature look-up tables. This is illustrated by automated translation of English into either French or German. The paper contin- ues to formalise the feature-based approach via a model-based, Montague semantics, which extends previous work on the semantics of English verb phrases. In so doing, repercussions of and to this framework in conducting a contrastive semantic study are considered. The model-based approach also promises to provide support for a more sophisticated approach to translation through logical proof; the paper indicates further work required for the fulfilment of this promise
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