Validation of queries to a relational database

This thesis addresses the problem of preventing users of a data base system from interrogating it with query language expressions which are syntactically and semantically valid but which do not match the user's intentions. A method of assisting users of a relational data base to formulate query language expressions which are valid representations of the abstract query which the user wishes to put is developed. The central focus of the thesis is a method of communicating the critical aspects of the semantics of the relation which would be generated in response to a user's proposed operations on the data base. Certain classes of user error which can arise when using a relational algebra query system are identified, and a method of demonstrating their invalidity is demonstrated. This is achieved by representing via a graph the consequences of operations on relations. Also developed are techniques allowing the generation of pseudo-natural language text describing the relations which would be created as the result of the user's proposed query language operations. A method of allowing the creators of data base relations to incorporate informative semantic data about their relations is developed. A method of permitting this data to be modified by query language operations is specified. Pragmatic linguistic considerations which arise when this data is used to generate pseudo-natural language statements are addressed, and examples of the system's use are given

Non-canonical subject marking in Romanian : status and evolution of the MIHI EST construction

This dissertation deals with the MIHI EST construction in Romanian, illustrated in (1), in which the verb fi ‘be’ combines with a dative experiencer and a state noun. This construction represents in Romanian the most natural way of expressing psychological or physiological states. It traces back to Latin, but it disappeared from all other Romance languages, which use a HABEO structure to express this kind of states. Hence, within the Romance context the MIHI EST construction is a unique phenomenon in Romanian. (1) Mi- e foame / sete / frică me.DAT= is hunger / thirst / fear ‘I am hungry/ thirsty/ afraid’ The present study is a part of a larger project that aims to measure Romanian’s tendency to non-canonical subject marking claimed in the literature. If confirmed, this tendency contradicts the hypothesis that European languages replace non-canonical structures with canonical structures. Within this comprehensive project, my dissertation contributes with an in-depth analysis of the MIHI EST construction. By means of a synchronic and diachronic corpus-based study, I investigate (i) the status of the core arguments of the MIHI EST structure, i.e. the dative experiencer and the nominative state noun, traditionally analyzed as the subject, and (ii) the evolution of the MIHI EST construction from the first texts in Romanian dating from the 16th century until today. My investigation reveals that, with respect to a series of largely accepted syntactic subject criteria, the dative experiencer behaves like nominative subjects. These criteria are the following: word order, non-realization of the subject in subordinate clauses when coreferential with the subject of the main clause, movement of the subject of the subordinate clause to the position of subject of the main clause, deletion of subjects in telegraphic style, bare quantifiers in clause-initial position, and the ability to take secondary predicates. In contrast, a thorough examination of the state noun shows that, although it is nominative-marked and triggers verb agreement, it does not behave like a syntactic subject, but shows predicate behavior. As for the evolution of the MIHI EST structure, the analysis of the data reveals that, throughout the centuries, periods of modernization alternate with periods of stabilization. With other words, periods in which new nouns are accepted in the MIHI EST structure alternate with periods in which the construction gains in stability by a more frequent usage of the same existing combinations. Based on the presented facts, I claim that the MIHI EST construction shows a certain tendency toward expansion, since in present-day Romanian it can coerce nouns coming from other semantic fields into the construction’s psychological or physiological interpretation. The question arises whether the expansion of the MIHI EST construction constitutes sufficient evidence for a propensity in Romanian toward non-canonical marking of core arguments, which would go against the tendency of the European languages toward canonical marking. Further research covering other types of predicates, such as adjectives, adverbs or verbs that occur with non-canonical subjects is required in order to validate this claim

Temporal Information Extraction and Knowledge Base Population

Temporal Information Extraction (TIE) from text plays an important role in many Natural Language Processing and Database applications. Many features of the world are time-dependent, and rich temporal knowledge is required for a more complete and precise understanding of the world. In this thesis we address aspects of two core tasks in TIE. First, we provide a new corpus of labeled temporal relations between events and temporal expressions, dense enough to facilitate a change in research directions from relation classification to identification, and present a system designed to address corresponding new challenges. Second, we implement a novel approach for the discovery and aggregation of temporal information about entity-centric fluent relations

Meaning versus Grammar

This volume investigates the complicated relationship between grammar, computation, and meaning in natural languages. It details conditions under which meaning-driven processing of natural language is feasible, discusses an operational and accessible implementation of the grammatical cycle for Dutch, and offers analyses of a number of further conjectures about constituency and entailment in natural language

Proof Support for Common Logic

We present an extension of the Heterogeneous Tool Set HETS that enables proof support for Common Logic. This is achieved via logic translations that relate Common Logic and some of its sublogics to already supported logics and automated theorem proving systems. We thus provide the first full theorem proving support for Common Logic, including the possibility of verifying meta-theoretical relationships between Common Logic theories

Topological Foundations of Cognitive Science

A collection of papers presented at the First International Summer Institute in Cognitive Science, University at Buffalo, July 1994, including the following papers: ** Topological Foundations of Cognitive Science, Barry Smith ** The Bounds of Axiomatisation, Graham White ** Rethinking Boundaries, Wojciech Zelaniec ** Sheaf Mereology and Space Cognition, Jean Petitot ** A Mereotopological Definition of 'Point', Carola Eschenbach ** Discreteness, Finiteness, and the Structure of Topological Spaces, Christopher Habel ** Mass Reference and the Geometry of Solids, Almerindo E. Ojeda ** Defining a 'Doughnut' Made Difficult, N .M. Gotts ** A Theory of Spatial Regions with Indeterminate Boundaries, A.G. Cohn and N.M. Gotts ** Mereotopological Construction of Time from Events, Fabio Pianesi and Achille C. Varzi ** Computational Mereology: A Study of Part-of Relations for Multi-media Indexing, Wlodek Zadrozny and Michelle Ki

Methods for taking semantic graphs apart and putting them back together again

The thesis develops a competitive compositional semantic parser for Abstract Meaning Representation (AMR). This approach combines a neural model with mechanisms that echo ideas from compositional semantic construction in a new, simple dependency structure. The thesis first tackles the task of generating structured training data necessary for a compositional approach, by developing the linguistically motivated AM algebra. Encoding the terms over the AM algebra as dependency trees yields a simple semantic parsing model where neural tagging and dependency models predict interpretable, meaningful operations that construct the AMR.Diese Dissertation entwickelt einen kompositionellen semantischen Parser für den Graphformalismus Abstract Meaning Representation (AMR). Der Ansatz kombiniert ein neuronales Modell mit Mechanismen, die Ideen der klassischen kompositionellen semantischen Konstruktion widerspiegeln. Die Arbeit geht zunächst das Problem an, strukturierte latente Trainingsdaten zu erzeugen die für den kompositionellen Ansatz nötig sind. Für diesen Zweck wird die linguistisch motivierte AM Algebra entwickelt. Indem die Terme der AM Algebra als Dependenzbäume ausgedrückt werden, erhalten wir ein Modell für semantisches Parsen, in dem neuronale Tagging- und Dependenzmodelle interpretierbare, aussagekräftige Operationen vorhersagen die dann den AMR Graphen erzeugen. Damit erreicht das Modell starke Evaluationsergebnisse und deutliche Verbesserungen gegenüber einem weniger strukturierten Vergleichsmodell.DF

Logic for Natural Language Analysis

This work investigates the use of formal logic as a practical tool for describing the syntax and semantics of a subset of English, and building a computer program to answer data base queries expressed in that subset. To achieve an intimate connection between logical descriptions and computer programs, all the descriptions given are in the definite clause subset of the predicate calculus, which is the basis of the programming language Prolog. The logical descriptions run directly as efficient Prolog programs. Three aspects of the use of logic in natural language analysis are covered: formal representation of syntactic rules by means of a grammar formalism based on logic, extraposition grammars;. formal semantics for the chosen English subset, appropriate for data base queries; informal semantic and pragmatic rules to translate analysed sentences into their formal semantics. On these three aspects, the work improves and extends earlier work by Colmerauer and others, where the use of computational logic in language analysis was first introduced

Semantic networks

AbstractA semantic network is a graph of the structure of meaning. This article introduces semantic network systems and their importance in Artificial Intelligence, followed by I. the early background; II. a summary of the basic ideas and issues including link types, frame systems, case relations, link valence, abstraction, inheritance hierarchies and logic extensions; and III. a survey of ‘world-structuring’ systems including ontologies, causal link models, continuous models, relevance, formal dictionaries, semantic primitives and intersecting inference hierarchies. Speed and practical implementation are briefly discussed. The conclusion argues for a synthesis of relational graph theory, graph-grammar theory and order theory based on semantic primitives and multiple intersecting inference hierarchies