39703480
Skeletal Structural Descriptions
In this paper we explore the idea of characterizing sentences by the shapes of their structural descriptions only; for example, in the case of context free grammars, by the shapes of the derivation trees only. Such structural descriptions will be called skeletons . A skeleton exhibits all of the grouping structure (phrase structure) of the sentence without naming the syntactic categories used in the description. The inclusion of syntactic categories as variables is primarily a question of economy of description. Every context free grammar is strongly equivalent to a skeletal grammar, in a sense made precise in the paper. Besides clarifying the role of skeletons in mathematical linguistics, we show that skeletal automata provide a characterization of local sets, remedying a “defect” in the usual tree automata theory. We extend the method of skeletal structural descriptions to other forms of tree describing systems. We also suggest a theoretical basis for grammatical inference based on grouping structure only.
38151734
Role of Constrained Computational Systems in Natural Language Processing
Abstract The use of constrained formal/computational systems just adequate for modeling various aspects of language—syntax, semantics, pragmatics and discourse, among others, has proved to be an effective research strategy leading to deep understanding of these aspects, with implications to both machine processing and human processing. This approach enables one to distinguish between the universal and stipulative constraints. This is in contrast to an approach where we start with the most powerful formal/computational system and then model the phenomena by making all constraints stipulative in a sense. The use of constrained systems for modeling leads to some novel ways of describing locality of structures and brings out the relationship between the complexity of description of primitives and local computations over them. These ideas serve to unify theoretical, computational and statistical aspects of natural languages processing in AI. It is expected that this approach will be productive in other domains of AI.
3203844
Some Novel Applications of Explanation-Based Learning for Parsing Lexicalized Tree-Adjoining Grammars
In this paper we present some novel applications of Explanation-Based Learning (EBL) technique to parsing Lexicalized Tree-Adjoining grammars. The novel aspects are (a) immediate generalization of parses in the training set, (b) generalization over recursive structures and (c) representation of generalized parses as Finite State Transducers. A highly impoverished parser called a "stapler" has also been introduced. We present experimental results using EBL for different corpora and architectures to show the effectiveness of our approach.
2954113
Tree Adjunct Grammars
In this paper, a tree generating system called a tree adjunct grammar is described and its formal properties are studied relating them to the tree generating systems of Brainerd (Information and Control14 (1969), 217-231) and Rounds (Mathematical Systems Theory 4 (1970), 257-287) and to the recognizable sets and local sets discussed by Thatcher (Journal of Computer and System Sciences1 (1967), 317-322; 4 (1970), 339-367) and Rounds. Linguistic relevance of these systems has been briefly discussed also.
16208693
Some results in tree automata
In this paper, we will essentially present three results in tree automata. Two of these are concerned with certain open problems posed by Rounds [1] and Martin and Vere [3], and the third one is related to the result of Peters and Ritchie [4].
 First we will briefly state the results and then describe them in some detail in Sections 2, 3, and 4.
5138605
String Adjunct Grammars
In this paper, we have introduced a new style of formal grammars called String Adjunct Grammars (AG). The rules in an AG have a considerably different formal character as compared to the 'rewrite rule' in a Phrase Structure Grammar (PSG). Such a study of formal grammars of different styles (i.e., formal character of rules) is of great interest because each style is well suited for characterizing certain aspects of natural language structure and is awkward for characterizing certain other aspects. Several subclasses of AG's motivated by strong linguistic considerations have been studied, comparing them with PSG's. Linguistic relevance of these grammars (and other gram mars suggested by this study) has been discussed at the end.
8028526
Enhancing Web privacy protection through declarative policies
The platform for privacy preferences (P3P) is a W3C framework for Web privacy management. It provides a standard vocabulary that Websites can use to describe their privacy practices. The presence of Web site published P3P policies enable users to configure Web browsers to allow, block or warn users during access and data exchange with Websites. It's a good idea that unfortunately is rarely used. We identify three primary reasons: (i) the languages available to describe user privacy preferences are not sufficiently expressive, (ii) P3P policies published by Web sites are not trusted by users and (iii) P3P framework does not provide a coherent view of available privacy protection mechanisms to the user towards addressing these issues; we present enhancements to the P3P framework. We use a more expressive policy language based on deontic concepts to describe user privacy-related policies, constraints and preferences. We introduce a new trust model for Websites and describe its use in user privacy preferences. Finally, we present sample policies to demonstrate the relevance of our work and offer it as an effective starting point towards enhancing Web privacy management.
2898024
Using OWL in a Pervasive Computing Broker
Computing is moving toward a pervasive context-aware environment in which agents with limited resources will require external support to help them become context-aware. In this paper, we describe an agent based architecture called Context Broker Architecture (CoBrA) to help these agents to acquire, reason about and share context knowledge. A key component in our architecture is an explicit context ontology defined using the Web Ontology Language (OWL). This ontology models the basic concepts of people, agents, places, and presentation events. We also describe a use case scenario and prototype design of CoBrA in an intelligent meeting room environment.
5320074
Using Lexicalized Tags for Machine Translation
Lexicalized Tree Adjoining Grammar (LTAG) is an attractive formalism for linguistic description mainly because of its extended domain of locality and its factoring recursion out from the domain of local dependencies (Joshi, 1985, Kroch and Joshi, 1985, Abeille, 1988). LTAG's extended domain of locality enables one to localize syntactic dependencies (such as filler-gap), as well as semantic dependencies (such as predicate-arguments). The aim of this paper is to show that these properties combined with the lexicalized property of LTAG are especially attractive for machine translation.The transfer between two languages, such as French and English, can be done by putting directly into correspondence large elementary units without going through some interlingual representation and without major changes to the source and target grammars. The underlying formalism for the transfer is "synchronous Tree Adjoining Grammars" (Shieber and Schabes [1990]). Transfer rules are stated as correspondences between nodes of trees of large domain of locality which are associated with words. We can thus define lexical transfer rules that avoid the defects of a mere word-to-word approach but still benefit from the simplicity and elegance of a lexical approach.We rely on the French and English LTAG grammars (Abeille [1988], Abeille [1990 (b)], Abeille et al. [1990], Abeille and Schabes [1989, 1990]) that have been designed over the past two years jointly at University of Pennsylvania and University of Paris 7-Jussieu.
1644414
A 2-slot time-division multiplexing (TDM) interconnect network for gigascale integration (GSI)
In many wire-limited VLSI digital systems the time delay of the longest global interconnect can be a significant percentage of the clock period. However, because semi-global and global wires with shorter wire lengths can have a much smaller time delay, they can remain idle (i.e. not switching) for a significant portion of the clock period even after their data has been transmitted. To capitalize on this phenomenon, this paper proposes that a low-overhead 2-slot Time Division Multiplexing (TDM) network should be incorporated into the multilevel interconnect architectures of future GSI systems to help reduce the escalating manufacturing costs that are primarily due to the projected increase in the number of metal layers. Using system-level interconnect prediction (SLIP) techniques, it is shown that a 20% reduction in the number of metal levels could be achieved for a 100M transistor VLSI system with only a 5-10% increase in power dissipation.
31295380
Intelligent Agents for Mobile and Embedded Devices
The pervasive computing environments of the near future will involve the interactions, coordination and cooperation of numerous, casually accessible, and often invisible computing devices. These devices, whether carried on our person or embedded in our homes, businesses and classrooms, will connect via wireless and wired links to one another and to the global networking infrastructure. The result will be a networking milieu with a new level of openness. The localized and dynamic nature of their interactions raises many new issues that draw on and challenge the disciplines of agents, distributed systems, and security. This paper describes recent work by the UMBC Ebiquity research group which addresses some of these issues.