On the representation of temporal knowledge

The growing interest in an adequate modelling of time in Artificial Intelligence has given rise to the research discipline of Temporal Reasoning (TR). Due to different views, different approaches towards TR such as PL1, modal logics or Allen\u27s intervall logic have been investigated. It was realized at an early stage that each of this approaches has some strong points whereas it suffers from certain drawbacks. Thus recently, a number of research activities have emerged aiming at a combination of the classical paradigms for representing time. In the first part of this paper, we present an overview of the most important approaches to the integration of temporal knowledge into logic programming. In the second part, we present the CRONOLOG temporal logic programming language which has been developed to cover the quintessence of the approaches presented before. The third part of the paper describes TRAM, which it is an extension of CRONOLOG to a temporal knowledge representation system. Using TRAM it is possible to represent knowledge depending on time and to reason about this knowledge. TRAM has been conceptually based on a combination of modal logics with Allen\u27s interval logic. We present the Extended Modal Logics (EML) which establishes the theoretical framework for TRAM. We define an operational semantics and a horizontal compilation scheme for TRAM

Applying transition rules to bitemporal deductive databases for integrity constraint checking

A bitemporal deductive database is a deductive database that supports valid and transaction time. A set of facts to be inserted and/or deleted in a bitemporal deductive database can be done in a past, present or future valid time. This circumstance causes that the maintenance of database consistency becomes more hard. In this paper, we present a new approach to reduce the difficulty of this problem, based on applying transition and event rules, which explicitly define the insertions and deletions given by a database update. Transition rules range over all the possible cases in which an update could violate some integrity contraint. Although, we have a large amount of transition rules, for each one we argue its utility or we eliminate it. We augment a database with this set of transition and event rules and then standard SLDNF resolution can be used to check satisfaction of integrity constraints.Peer ReviewedPostprint (author's final draft

Knowledge Representation with Multiple Logical Theories and Time

We present a knowledge representation framework where a collection of logic programs can be combined together by means of meta-level program composition operations. Each object-level program is composed of a collection of extended clauses, equipped with a time interval representing the time period in which they hold. The interaction between program composition operations and time yields a powerful knowledge representation language in which many applications can be naturally developed. The language is given a meta-level semantics which also provides an executable specification. Moreover, we define an abstract semantics by extending the immediate consequence operator from a single logic program to compositions of logic programs and taking into account time intervals. The operational, meta-level semantics is proven sound and complete with respect to the abstract bottom-up semantics. The approach is further extended in order to cope with the problem of reasoning over joined intervals of time. Three applications in the field of business regulations are shown

Temporal reasoning in a logic programming language with modularity

Actualmente os Sistemas de Informação Organizacionais (SIO) lidam cada vez mais com informação que tem dependências temporais. Neste trabalho concebemos um ambiente de trabalho para construir e manter SIO Temporais. Este ambiente assenta sobre um linguagem lógica denominada Temporal Contextua) Logic Programming que integra modularidade com raciocínio temporal fazendo com que a utilização de um módulo dependa do tempo do contexto. Esta linguagem é a evolução de uma outra, também introduzida nesta tese, que combina Contextua) Logic Programming com Temporal Annotated Constraint Logic Programming, na qual a modularidade e o tempo são características ortogonais. Ambas as linguagens são formalmente discutidas e exemplificadas. As principais contribuições do trabalho descrito nesta tese incluem: • Optimização de Contextua) Logic Programming (CxLP) através de interpretação abstracta. • Sintaxe e semântica operacional para uma linguagem que combina de um modo independente as linguagens Temporal Annotated Constraint Logic Programming (TACLP) e CxLP. É apresentado um compilador para esta linguagem. • Linguagem (sintaxe e semântica) que integra de um modo inovador modularidade (CxLP) com raciocínio temporal (TACLP). Nesta linguagem a utilização de um dado módulo está dependente do tempo do contexto. É descrito um interpretador e um compilador para esta linguagem. • Ambiente de trabalho para construir e fazer a manutenção de SIO Temporais. Assenta sobre uma especificação revista da linguagem ISCO, adicionando classes e manipulação de dados temporais. É fornecido um compilador em que a linguagem resultante é a descrita no item anterior. ABSTRACT- Current Organisational Information Systems (OIS) deal with more and more Infor-mation that, is time dependent. In this work we provide a framework to construct and maintain Temporal OIS. This framework builds upon a logical language called Temporal Contextual. Logic Programming that deeply integrates modularity with tem-poral reasoning making the usage of a module time dependent. This language is an evolution of another one, also introduced in this thesis, that combines Contextual Logic Programming with Temporal Annotated Constraint Logic Programming where modularity and time are orthogonal features. Both languages are formally discussed and illustrated. The main contributions of the work described in this thesis include: • Optimisation of Contextual Logic Programming (CxLP) through abstract interpretation. • Syntax and operational semantics for an independent combination of the temporal framework Temporal Annotated Constraint Logic Programming (TACLP) and CxLP. A compiler for this language is also provided. • Language (syntax and semantics) that integrates in a innovative way modularity (CxLP) with temporal reasoning (TACLP). In this language the usage of a given module depends of the time of the context. An interpreter and a compiler for this language are described. • Framework to construct and maintain Temporal Organisational Information Systems. It builds upon a revised specification of the language ISCO, adding temporal classes and temporal data manipulation. A compiler targeting the language presented in the previous item is also given

A Demo of Query Languages for Temporal Databases

Cílem této práce je vytvorit aplikaci pro prepojení odlišních prístupu k temporalním datam. Hlavní myšlenkou je umožniť užívateli práci s použitím jazyka TSQL2 nebo ATSQL bez nutnosti zásahu užívatele do relačního databázového systému. Rovnež tak je součastí práce implementace rozhraní JDBC a demonstrační aplikace pro testovaní temporálních dotazu.The aim of this work is to create an application for interconnect diferrences among temporal databases. The main idea of this project is allow user work with languages TSQL2 and ATSQL without user intervention into relation database system. This work also contain implementation of interface JDBC and demonstration application for testing temporal queries.

Processor of TSQL2 on a Relational Database System

Tato práce se zabývá návrhem a implementací interpretu jazyka TSQL2 pro překlad do SQL. Stručně seznamuje čtenáře s pojmem temporální databáze a přestavuje jazyk TSQL2. Jsou zde také popsány existující implementace temporálních databází a je zhodnocena jejich praktická použitelnost pro správu temporálních dat. Hlavní částí práce je potom popis návrhu a implementace překladače jazyka TSQL2. Výsledkem práce je funkční interpret jazyka TSQL2 implementovaný v jazyce Java jako nadstavba nad ovladač JDBC.This thesis is focused on design and implementation of TSQL2 language interpreter for SQL. It briefly introduces temporal database and language TSQL2. Currently available implementations of temporal database systems are introduced and their practical usability for temporal data is reviewed. Main part of this thesis covers design and implementation of TSQL2 interpreter. A working TSQL2 interpreter implemented in Java as JDBC adapter is the result of this work.

Time granularity in simulation models within a multi-agent system

The understanding of how processes in natural phenomena interact at different scales of time has been a great challenge for humans. How information is transferred across scales is fundamental if one tries to scale up from finer to coarse levels of granularity. Computer simulation has been a powerful tool to determine the appropriate amount of detail one has to impose when developing simulation models of such phenomena. However, it has proved difficult to represent change at many scales of time and subject to cyclical processes. This issue has received little attention in traditional AI work on temporal reasoning but it becomes important in more complex domains, such as ecological modelling. Traditionally, models of ecosystems have been developed using imperative languages. Very few of those temporal logic theories have been used for the specification of simulation models in ecology. The aggregation of processes working at different scales of time is difficult (sometimes impossible) to do reliably. The reason is because these processes influence each other, and their functionality does not always scale to other levels. Thus the problems to tackle are representing cyclical and interacting processes at many scales and providing a framework to make the integration of such processes more reliable. We propose a framework for temporal modelling which allows modellers to represent cyclical and interacting processes at many scales. This theory combines both aspects by means of modular temporal classes and an underlying special temporal unification algorithm. To allow integration of different models they are developed as agents with a degree of autonomy in a multi-agent system architecture. This Ecoagency framework is evaluated on ecological modelling problems and it is compared to a formal language for describing ecological systems

Processor of TSQL2 on Post-Relational Databases in Oracle Database

Středem zájmu této práce jsou temporální databáze a jejich multimediální a prostorové rozšíření. V úvodu práce jsou shrnuty výsledky výzkumu v oblasti temporálních databází, jsou představeny základní koncepty jazyka TSQL2 a postrelační rozšíření databáze Oracle. Stěžejní částí  práce je návrh interpretu jako vrstvy mezi uživatelskou aplikací a relační databází. Práce se dále zabývá kontrolou integritních omezení v temporální databázi a navrhuje její realizaci. Výstupem práce je funkční interpret jazyka TSQL2, který je schopný ukládat postrelační data.This thesis focuses on temporal databases and their multimedia and spatial extensions. The introduction of this work summarizes results in the area of research of temporal databases - key concepts of a TSQL2 language and post-relational extension of Oracle database are introduced. Main part of the thesis is design of an interpreter as a layer between user application and relational database.  In the next part of the thesis control of integrity constraints in temporal databases are discussed. Result of this work is functional interpreter of TSQL2 language able to store post-relational data.