A Potpourri of Reason Maintenance Methods

We present novel methods to compute changes to materialized views in logic databases like those used by rule-based reasoners. Such reasoners have to address the problem of changing axioms in the presence of materializations of derived atoms. Existing approaches have drawbacks: some require to generate and evaluate large transformed programs that are in Datalog - while the source program is in Datalog and significantly smaller; some recompute the whole extension of a predicate even if only a small part of this extension is affected by the change. The methods presented in this article overcome these drawbacks and derive additional information useful also for explanation, at the price of an adaptation of the semi-naive forward chaining

A beginner's guide to belief revision and truth maintenance systems

This brief note is intended to familiarize the non-TMS audience with some of the basic ideas surrounding classic TMS's (truth maintenance systems), namely the justification-based TMS and the assumption-based TMS. Topics of further interest include the relation between non-monotonic logics and TMS's, efficiency and search issues, complexity concerns, as well as the variety of TMS systems that have surfaced in the past decade or so. These include probabilistic-based TMS systems, fuzzy TMS systems, tri-valued belief systems, and so on

AN APPROACH TO DEPENDENCY DIRECTED BACKTRACKING USING DOMAIN SPECIFIC KNOWLEDGE

The idea of dependency directed backtracking proposed by Stallman and Sussman (1977) offers significant advantages over heuristic starch schemes with chronological backtracking which waste much effort by discarding many "good" choices when backtracking situations arise. However, we have found that existing non-chronological backtracking machinery is not suitable for certain types of problems, namely, those where choices do not follow logically from previous choices, but are based on a heuristic evaluation of a constrained set of alternatives. This is because a choice is not justified by a âset of supportâ (of previous choices), but because its advantages outweigh its drawbacks in comparison to its competitors. What is needed for these types of problems is a scheme where the advantages and disadvantages of choices are explicitly recorded during problem solving. Then, if an unacceptable situation arises, information about the nature of the unacceptability and the tradeoffs can be used to determine the most appropriate backtracking point. Further, this requires the problem solver to use its hindsight to preserve those "good" intervening choices that were made chronologically after the "bad" choice, and to resume its subsequent reasoning in fight of the modified set of constraints. In this paper, we describe a problem solver for non-chronological backtracking in situations involving tradeoffs. By endowing the backtracker with access to domain-specific knowledge, a highly contextual approach to reasoning in dependency directed backtracking situations can be achieved.Information Systems Working Papers Serie

A Synthesis of Language Ideas for AI Control Structures

Two well known programming methodologies for artificial intelligence research are compared, the so-called pattern-directed invocation languages and the object-oriented languages. The features and limitations of both approaches are discussed. We show that pattern-directed invocation is a more general formalism, but entails a serious loss of efficiency. We then go on to demonstrate that a language for artificial intelligence research can be created that contains the best features of both approaches.MIT Artificial Intelligence Laborator

Vantagens do uso de regras nas pesquisas on-line

In this paper we present De.:SID, a rule-based Intelligent Online Survey program. We have incorporated three rule knowledge bases in a standard online survey architecture that are used to control three vital components on a survey: (1) the dependencies between questions, i.e. the structure and survey branching logic, (2) the decision regarding the selection of the next question to be asked, and (3) the inconsistency detection between answers to different questions. These rule-based components allow us to escape a predetermined question sequence, achieving flexibility and adaptability to the user’s answers; besides, they enhance usability allowing an easy navigation along the different survey questions and the possibility to backtrack and revise the answers, at any moment, without loosing global coherence. There is an explicit treatment of inconsistent situations by exposing them and inviting the user to revise his answers. De.:SID benefits from the qualities that are generally associated with rulebased systems: (1) separation from other system elements (database, middleware and web graphical user interfaces) allowing its explicit management, reusability and independent modification, (2) externalization which allows everyone to know and understand the decision making process, and finally (3) easy modification of rules that are modular and can be easily deleted, inserted or changed. Resumo: Neste artigo, descrevemos o De.:SID, uma aplicação dos Sistemas Baseados em Regras a um programa de inquérito “online” inteligente. Incorporámos no programa três bases de conhecimento baseadas em regras que controlam três componentes vitais num inquérito: (1) as dependências entre as várias perguntas e as respostas, ou seja a própria estrutura e a lógica de ramificação do inquérito; (2) a decisão quanto à selecção da próxima pergunta a ser colocada, e (3) a detecção de inconsistências entre as várias respostas. Estes componentes permitem que não se imponha uma ordem pré-determinada na colocação das perguntas, dotando o sistema de flexibilidade e capacidade de adaptação às respostas do utilizador; permitem também uma fácil e livre navegabilidade ao longo das várias perguntas e a possibilidade da revisão das respostas sem perder a coerência do inquérito. As situações de inconsistência nas respostas podem ser representadas, expondo as respostas envolvidas e convidando o utilizador a rever uma dessas respostas. De.:SID beneficia das qualidades que estão normalmente associadas ao uso de regras: (1) a separação e independência face aos restante componentes do sistema, (2) a exposição e a transparência dos processos de tomada de decisões associados ao inquérito, e, (3) a rápida e fácil mudança das regras devido à sua modularidade.Neste artigo, descrevemos o De.:SID, uma aplicação dos Sistemas Baseados em Regras a um programa de inquérito “online” inteligente. Incorporámos no programa três bases de conhecimento baseadas em regras que controlam três componentes vitais num inquérito: (1) as dependências entre as várias perguntas e as respostas, ou seja a própria estrutura e a lógica de ramificação do inquérito; (2) a decisão quanto à selecção da próxima pergunta a ser colocada, e (3) a detecção de inconsistências entre as várias respostas. Estes componentes permitem que não se imponha uma ordem pré-determinada na colocação das perguntas, dotando o sistema de flexibilidade e capacidade de adaptação às respostas do utilizador; permitem também uma fácil e livre navegabilidade ao longo das várias perguntas e a possibilidade da revisão das respostas sem perder a coerência do inquérito. As situações de inconsistência nas respostas podem ser representadas, expondo as respostas envolvidas e convidando o utilizador a rever uma dessas respostas. De.:SID beneficia das qualidades que estão normalmente associadas ao uso de regras: (1) a separação e independência face aos restante componentes do sistema, (2) a exposição e a transparência dos processos de tomada de decisões associados ao inquérito, e, (3) a rápida e fácil mudança das regras devido à sua modularidade.peerreviewe

Reason Maintenance - State of the Art

This paper describes state of the art in reason maintenance with a focus on its future usage in the KiWi project. To give a bigger picture of the field, it also mentions closely related issues such as non-monotonic logic and paraconsistency. The paper is organized as follows: first, two motivating scenarios referring to semantic wikis are presented which are then used to introduce the different reason maintenance techniques

Work experience on automation of processing of survey measurements of backfill of mines of Uralkali PJSC

During the last years of development of Verkhnekamsk potassium salt field (VKPSF) activities that aimed to prevent harmful impact of underground mines on earth's surface and industrial, civil and natural objects located on it and water breakthrough into mines became relevant. One of the main methods to control these phenomena is to backfill empty space with solid wastes of potassium ore processing. Growing volume of backfill works leads to an increase in survey service of mining enterprises, which does instrumental control over fulfillment of design parameters of backfilling mines. In this regard, there are questions raised on automation of processing of results of instrumental measurements of backfill volumes and compiling graphic and text reporting documentation. In order to solve this problem the authors of the article developed a software module that allows to solve in automated mode most of the tasks that are faced by staff of survey departments of VKPSF mines who monitor compliance with design parameters of volume of backfilling operations. The article provides information on functional possibilities and technical architecture of a software module. Examples of interface solutions and information on volumes of reporting documents being created are given. A developed software module is integrated into created mining and geological information system of Uralkali PJSC. A system is created with direct participation of the authors and provides 21 automated workplaces for various mining specialists (miners, geologists, mine surveyors, geophysicists, geomechanics, environmentalists etc.) starting from the primary link in mines and ending with the management of Uralkali PJSC

Frame-Based Knowledge Representation

This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. The author was sponsored by the Institute of International Education on an ITT-fellowship.The paper introduces a language for representing knowledge in a declarative form. With this language it is possible to define knowledge about a certain domain by introducing a number of concepts and by specifying their interrelations. The paper is meant to be an informal introduction to the language. We present the available constructs, describe their meaning and present a number of examples. In other papers (currently in preparation) we will give a formal semantics of the language, introduce the interference theory and discuss a possible procedural embedding.MIT Artificial Intelligence Laboratory Institute of International Educatio

Formalizing the Expertise of the Assembly Language Programmer

A novel compiler strategy for generating high quality code is described. The quality of the code results from reimplementing the program in the target language using knowledge of the program's behavior. The research is a first step towards formalizing the expertise of the assembly language programmer. The ultimate goal is to formalize code generation and implementation techniques in the same way that parsing and code generation techniques have been formalized. An experimental code generator based on the reimplementation strategy will be constructed. The code generator will provide a framework for analyzing the costs, applicability, and effectiveness of various implementation techniques. Several common code generation problems will be studied. Code written by experienced programmers and code generated by a conventional optimizing compiler will provide standards of comparison.MIT Artificial Intelligence Laborator

The XPRT Description System

This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. The author was sponsored by the Institute of International Education on an ITT-fellowship.This paper introduces a frame-based description language and studies methods for reasoning about problems using knowledge expressed in the language. The system is based on the metaphor of a society of communicating experts and incorporates within this framework most of the currently known AI techniques, such as pattern-directed invocation, explicit control of reasoning, propagation of constraints, dependency recording, context mechanisms, message passing, conflict resolution, default reasoning, etc.MIT Artificial Intelligence Laboratory Institute of International Educatio