| { | |
| "paper_id": "A92-1038", | |
| "header": { | |
| "generated_with": "S2ORC 1.0.0", | |
| "date_generated": "2023-01-19T02:03:32.578670Z" | |
| }, | |
| "title": "Datenbank-DIALOG and the Relevance of Habitability", | |
| "authors": [ | |
| { | |
| "first": "Harald", | |
| "middle": [], | |
| "last": "Trost", | |
| "suffix": "", | |
| "affiliation": {}, | |
| "email": "" | |
| }, | |
| { | |
| "first": "Wolfgang", | |
| "middle": [], | |
| "last": "Heinz", | |
| "suffix": "", | |
| "affiliation": {}, | |
| "email": "" | |
| }, | |
| { | |
| "first": "Johannes", | |
| "middle": [], | |
| "last": "Matiasek", | |
| "suffix": "", | |
| "affiliation": {}, | |
| "email": "" | |
| }, | |
| { | |
| "first": "Ernst", | |
| "middle": [], | |
| "last": "Buchberger", | |
| "suffix": "", | |
| "affiliation": {}, | |
| "email": "" | |
| } | |
| ], | |
| "year": "", | |
| "venue": null, | |
| "identifiers": {}, | |
| "abstract": "", | |
| "pdf_parse": { | |
| "paper_id": "A92-1038", | |
| "_pdf_hash": "", | |
| "abstract": [], | |
| "body_text": [ | |
| { | |
| "text": "The paper focusses on the issue of habitability and how it is accounted for in Datenbank-DIALOG 1. Examples from the area of comparisons and measures--both ilnportant for many application domains and non-trivial from a linguistic point of view--demonstrate how design strategies can SUl)port the development of a habitahle system. Datenbank-DIALOG is a German language interface to relational databases. Since the development of a first prototype it has been tested in different enviromnents and continually been improved. Currently, in a large field test, Datenbank-DIALOG interfaces to a database about AI research in Austria. Questions sent by einail 2 are answered automatically.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Introduction", | |
| "sec_num": "1" | |
| }, | |
| { | |
| "text": "The system consists of four main components. The scanner breaks up the natural language query into tokens for morphological analysis. The parser l)erforms syntactic and semantic analysis creating one or--in case of ambiguities--more caseframes containing the query representation at the domain level. The interpretation of the query is performed in three stages. The mapping from domain-level to database-level predicates results in a DB-Caseframe, then a linearization step produces the Logical Form and finally a syntactic transformation leads to an SQL query. The answer is then given directly by the DBMS as the result of executing the SQL query.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Introduction", | |
| "sec_num": "1" | |
| }, | |
| { | |
| "text": "Experiments with NLIs indicate that the linguistic coverage of state-of-the-art systems is adequate. Savings in training time outweigh problems with queries not handled. Very important though is that the system behaves in a predictable way, i.e. is habitable, so that users can learn the types of acceptable queries very fast. wise, they will either face a continuously high rejection rate or--more likely, since humans adapt much better than computers--formulate their queries ill an unnecessarily simple and inefficient way.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Habitability", | |
| "sec_num": "2" | |
| }, | |
| { | |
| "text": "Hahitability cannot be judged solely on syntactic coverage. Queries must be correctly interpreted syntactically, semantically and pragmatically. While syntactic coverage depends solely on tile parser, semantic and pragmatic coverage must be considered with respect to the contents of the database to which the NLI connects.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Habitability", | |
| "sec_num": "2" | |
| }, | |
| { | |
| "text": "The grammar of Datenbank-DIALOG is completely domain-independent, designed to make the accepted suhlanguage as consistent as l)ossihle. Recent advances of linguistic theory were incorporated in its development, thus also facilitating implementation and maintenance. Two examples for this strategy are the treatment of determiners and verb-second (V2).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Habitability", | |
| "sec_num": "2" | |
| }, | |
| { | |
| "text": "Using results of Generalized Quantifiers Theory for natural language quantifiers (e.g. conservativity) a formal correspondence between GQ-formulas (representing the logical form of a query) and SQL-statements (formulas over the relational calculus) was estal)lished and implemented. This gives a sound theoretical basis for semantic interpretation and SQL generation. All extensional natural language determiners can be handled-matching the extensional nature of databases.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Habitability", | |
| "sec_num": "2" | |
| }, | |
| { | |
| "text": "In German finite verbs occur ill second position in main clauses (V2) and in final position in subordinate clauses. Ideas from (_;B-Theory are used for a uniform treatment. V2 is considered to be the result of a movernent from an underlying final position in the verb cluster to clause initial cornplementizer position. This movement is iml)lemented as a relation between the \"moved\" finite verb and its trace. In the case of main clauses, Vlin is \"moved back\" to the end of the verb cluster, and now the same mechanism applies uniformly. Thus both clause types are subject to the same syntactic and semantic constraints (which thus need only be stated once) and give rise to the same interpretation.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Habitability", | |
| "sec_num": "2" | |
| }, | |
| { | |
| "text": "A central concern ill querying databases are cornparisons between various kinds of objects. Comt)arisons involve a relation between values associated with a dimension and units of measure. Values may be given explicitly or implicitly by derivation (thus including superlatives).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "Linguistic means for expressing colnparison vary widely. Usually, comparison is associated with gradable adjectives and adverbs in various syntactic constructions: hal ein hgheres Gehalt (Aux+A/NP); verdient mehr (V+Adv); rail einem hgheren Gehall (A/PP). The interpretation of those expressions should be the same. Datenbank-DIALOG uses a compositional semantics and separates the lexical item from the underlying semantic relation, which may be shared by different words.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "More prol)lerns arise when specifying the value for the cornparison: ein hb'heres Gehalt als 20.000,-; ein Gehalt yon mehr als 20.000,-; mehr als 20.000,-Gehalt; verdient mehr als 20.000,-. The comparative and the value may be adjacent or not, and show up a.s PPs, complex determiners or adverbial phrases. All these constructions map onto the same semantic representation, a relation, a value along with a dimension and a unit--thus allowing to compare values with different units--and a compared object. This assures a uniform semantic treatment.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
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| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "In verdicnl mehr als Dr. Haid the value is specified only implicitly by referring to the salary of Dr. Haid. Despite the different structure of the corresponding SQL queries the user will hardly notice this fundarnental difference. For a habitable system it is necessary to provide solutions to both types of comparisons. Datenbank-DIALOG recognizes the different interpretations by the semantic type associated with the value of the phrase to be cornpared. If the value has the correct dimension, it may safely be inserted a.s an argulnent into the cornparison relation. Otherwise, Datenbank-DIALOG constructs a subquery giving the value by using the dominating relation and fitting the comparison object into the \"subject\" slot of the attribute. The resulting structure is processed analogously to a top-level query. As a consequence, anal)hora resolution may be apl)lied enabling Datenbank-DIALOG to give a correct interpretation of Weri verdient mehr als seini Vorgeselzler'?", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "Domain predicates need not uniquely deterrnine the relation and attributes of a corresponding predicate in the database. Datenbank-DIALOG splits the interpretation of an utterance into two stages: An interpretation in the domain model, i.e. a caseframe, which is then mapped (using a translation table) to an interpretation in the database lnodel, i.e. a DB-caseframe.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
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| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "This approach allows to interpret superficially similar queries as quite different SQL queries. Attributes with the same meaning stored in different tables (nursesalary vs. doctor-salary) can be treated as well as derived attributes (salary computed from basic + variable salary)--in short, the user should not need to know about the actual encoding of information. An interesting instance of this prillciple is the interpretation of Wieviele Patienten behandelt Dr. Haid. Whereas in one database rnodel the imrnber of patients is stored explicitly and can be treated analogously to the salary above, other database models contain this \"attribute\" only implicitly: the number of patients haz to be computed (counted) by the SQL query. To obtain these quite different interpretations, only a different mapping of the (contents of the) argurnent-slot of the predicate Treatment in the translation step between domain and databa.se level is required.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
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| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "A special case (where irnplicit attributes must be made explicit) are queries involving the comparison of two subqueries. This cannot be expressed in a single SQL query. A ternporary table has to be created containing the relevant count-attribute together with information on the object hearing that attribute. The actual comparison can then be made with the now explicit attribute.", | |
| "cite_spans": [], | |
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| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "Most problems with comparatives also occur with superlatives and are dealt with in an analogous way. One interesting phenomenon which has no direct parallel in comparative structures shows in Welcher Arzl, der in der Ambulanz arbeilet, verdient am meislen? In most cases Who has the highest salary among the doctors working in the casualty department? is the most plausible interpretation and should be preferred. To produce this reading, a kind of copying has to he performed: not only must the dominating relation be copied but also the restrictions on the subject slot (i.e., on the bearer of the attribute) have to be inherited. In Datenbank-DIALOG this copying works on the ca.seframe representation, and thus is able to handle restrictions resulting from different syntactic constructions, such as the lexicon (Ambulanzarzl), APs (in der Ambulanz arbeitende Arzl), PPs (Arzt aus der Ambulanz), NPs (Arzt der Ambulanz) and relative clauses ( Arzt, der in der Ambulanz arbeitet). All these constructions end up as modifications in the caseframe due to the compositional nature of our approach. Thus a unified solution for inheritance of modifiers in their various forms is achieved.", | |
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| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "A correct comparison is only possible if compared values are of the same dimension and share a unit of measure. Differences and incompatibilities may arise in different places: frorn special formatting conventions (e.g. 20000, 20.000,-, $20), when the user specifies a dimension and unit of measure verbatim (e.g. \"10 Meter\"), from the database, where coinparable columns may be a.ssociated with different units of Inca.sure. Datenbank-DIALOG solves this problem--by defining a normalized form azsociating values with units and transformation rules between measures of different units--at the scanner level (l)atterns, e.g. (late formats), at the parser level (linguistic information to fill the slots in the normalized value frame), at the interpretation level (procedures to transform constant values from one unit to another), at the database level (transformation fimctions of the query language).", | |
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| "eq_spans": [], | |
| "section": "Comparisons", | |
| "sec_num": "3" | |
| }, | |
| { | |
| "text": "Habitability is a rnost iinl)ortant feature of NLIs. Using comparison as examl)le we have shown how the design of Datenbank-DIALOG enhances habitability, in particular by: giving a uniform interpretation to semantically equivalent user queries of different syntactic and morphological appearance; enabling users to enter data in the form most convenient to them (formatting, unit conversion); removing the need for users to know about the database representations of the concepts they use (domain concepts vs. databa.se relations and attributes, implicit flmctions, unit conversion); making ambiguities explicit; and incorporating presupl)ositions (relation and restriction copying).", | |
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| "section": "Summary", | |
| "sec_num": "4" | |
| } | |
| ], | |
| "back_matter": [], | |
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