title string | abstract string |
|---|---|
The Computational Complexity of Probabilistic Planning | We examine the computational complexity of testing and finding small plans in
probabilistic planning domains with both flat and propositional
representations. The complexity of plan evaluation and existence varies with
the plan type sought; we examine totally ordered plans, acyclic plans, and
looping plans, and partial... |
SYNERGY: A Linear Planner Based on Genetic Programming | In this paper we describe SYNERGY, which is a highly parallelizable, linear
planning system that is based on the genetic programming paradigm. Rather than
reasoning about the world it is planning for, SYNERGY uses artificial
selection, recombination and fitness measure to generate linear plans that
solve conjunctive go... |
The Essence of Constraint Propagation | We show that several constraint propagation algorithms (also called (local)
consistency, consistency enforcing, Waltz, filtering or narrowing algorithms)
are instances of algorithms that deal with chaotic iteration. To this end we
propose a simple abstract framework that allows us to classify and compare
these algorith... |
Towards a computational theory of human daydreaming | This paper examines the phenomenon of daydreaming: spontaneously recalling or
imagining personal or vicarious experiences in the past or future. The
following important roles of daydreaming in human cognition are postulated:
plan preparation and rehearsal, learning from failures and successes, support
for processes of ... |
A reusable iterative optimization software library to solve
combinatorial problems with approximate reasoning | Real world combinatorial optimization problems such as scheduling are
typically too complex to solve with exact methods. Additionally, the problems
often have to observe vaguely specified constraints of different importance,
the available data may be uncertain, and compromises between antagonistic
criteria may be neces... |
Modeling Belief in Dynamic Systems, Part II: Revision and Update | The study of belief change has been an active area in philosophy and AI. In
recent years two special cases of belief change, belief revision and belief
update, have been studied in detail. In a companion paper (Friedman & Halpern,
1997), we introduce a new framework to model belief change. This framework
combines tempo... |
The Symbol Grounding Problem | How can the semantic interpretation of a formal symbol system be made
intrinsic to the system, rather than just parasitic on the meanings in our
heads? How can the meanings of the meaningless symbol tokens, manipulated
solely on the basis of their (arbitrary) shapes, be grounded in anything but
other meaningless symbol... |
Iterative Deepening Branch and Bound | In tree search problem the best-first search algorithm needs too much of
space . To remove such drawbacks of these algorithms the IDA* was developed
which is both space and time cost efficient. But again IDA* can give an optimal
solution for real valued problems like Flow shop scheduling, Travelling
Salesman and 0/1 Kn... |
Probabilistic Agent Programs | Agents are small programs that autonomously take actions based on changes in
their environment or ``state.'' Over the last few years, there have been an
increasing number of efforts to build agents that can interact and/or
collaborate with other agents. In one of these efforts, Eiter, Subrahmanian amd
Pick (AIJ, 108(1-... |
Cox's Theorem Revisited | The assumptions needed to prove Cox's Theorem are discussed and examined.
Various sets of assumptions under which a Cox-style theorem can be proved are
provided, although all are rather strong and, arguably, not natural. |
Uniform semantic treatment of default and autoepistemic logics | We revisit the issue of connections between two leading formalisms in
nonmonotonic reasoning: autoepistemic logic and default logic. For each logic
we develop a comprehensive semantic framework based on the notion of a belief
pair. The set of all belief pairs together with the so called knowledge
ordering forms a compl... |
On the accuracy and running time of GSAT | Randomized algorithms for deciding satisfiability were shown to be effective
in solving problems with thousands of variables. However, these algorithms are
not complete. That is, they provide no guarantee that a satisfying assignment,
if one exists, will be found. Thus, when studying randomized algorithms, there
are tw... |
Syntactic Autonomy: Why There is no Autonomy without Symbols and How
Self-Organization Might Evolve Them | Two different types of agency are discussed based on dynamically coherent and
incoherent couplings with an environment respectively. I propose that until a
private syntax (syntactic autonomy) is discovered by dynamically coherent
agents, there are no significant or interesting types of closure or autonomy.
When syntact... |
Consistency Management of Normal Logic Program by Top-down Abductive
Proof Procedure | This paper presents a method of computing a revision of a function-free
normal logic program. If an added rule is inconsistent with a program, that is,
if it leads to a situation such that no stable model exists for a new program,
then deletion and addition of rules are performed to avoid inconsistency. We
specify a re... |
Defeasible Reasoning in OSCAR | This is a system description for the OSCAR defeasible reasoner. |
Abductive and Consistency-Based Diagnosis Revisited: a Modeling
Perspective | Diagnostic reasoning has been characterized logically as consistency-based
reasoning or abductive reasoning. Previous analyses in the literature have
shown, on the one hand, that choosing the (in general more restrictive)
abductive definition may be appropriate or not, depending on the content of the
knowledge base [Co... |
ACLP: Integrating Abduction and Constraint Solving | ACLP is a system which combines abductive reasoning and constraint solving by
integrating the frameworks of Abductive Logic Programming (ALP) and Constraint
Logic Programming (CLP). It forms a general high-level knowledge representation
environment for abductive problems in Artificial Intelligence and other areas.
In A... |
Relevance Sensitive Non-Monotonic Inference on Belief Sequences | We present a method for relevance sensitive non-monotonic inference from
belief sequences which incorporates insights pertaining to prioritized
inference and relevance sensitive, inconsistency tolerant belief revision.
Our model uses a finite, logically open sequence of propositional formulas as
a representation for ... |
Probabilistic Default Reasoning with Conditional Constraints | We propose a combination of probabilistic reasoning from conditional
constraints with approaches to default reasoning from conditional knowledge
bases. In detail, we generalize the notions of Pearl's entailment in system Z,
Lehmann's lexicographic entailment, and Geffner's conditional entailment to
conditional constrai... |
A Compiler for Ordered Logic Programs | This paper describes a system, called PLP, for compiling ordered logic
programs into standard logic programs under the answer set semantics. In an
ordered logic program, rules are named by unique terms, and preferences among
rules are given by a set of dedicated atoms. An ordered logic program is
transformed into a sec... |
SLDNFA-system | The SLDNFA-system results from the LP+ project at the K.U.Leuven, which
investigates logics and proof procedures for these logics for declarative
knowledge representation. Within this project inductive definition logic
(ID-logic) is used as representation logic. Different solvers are being
developed for this logic and ... |
Logic Programs with Compiled Preferences | We describe an approach for compiling preferences into logic programs under
the answer set semantics. An ordered logic program is an extended logic program
in which rules are named by unique terms, and in which preferences among rules
are given by a set of dedicated atoms. An ordered logic program is transformed
into a... |
Fuzzy Approaches to Abductive Inference | This paper proposes two kinds of fuzzy abductive inference in the framework
of fuzzy rule base. The abductive inference processes described here depend on
the semantic of the rule. We distinguish two classes of interpretation of a
fuzzy rule, certainty generation rules and possible generation rules. In this
paper we pr... |
Problem solving in ID-logic with aggregates: some experiments | The goal of the LP+ project at the K.U.Leuven is to design an expressive
logic, suitable for declarative knowledge representation, and to develop
intelligent systems based on Logic Programming technology for solving
computational problems using the declarative specifications. The ID-logic is an
integration of typed cla... |
Optimal Belief Revision | We propose a new approach to belief revision that provides a way to change
knowledge bases with a minimum of effort. We call this way of revising belief
states optimal belief revision. Our revision method gives special attention to
the fact that most belief revision processes are directed to a specific
informational ob... |
cc-Golog: Towards More Realistic Logic-Based Robot Controllers | High-level robot controllers in realistic domains typically deal with
processes which operate concurrently, change the world continuously, and where
the execution of actions is event-driven as in ``charge the batteries as soon
as the voltage level is low''. While non-logic-based robot control languages
are well suited ... |
Smodels: A System for Answer Set Programming | The Smodels system implements the stable model semantics for normal logic
programs. It handles a subclass of programs which contain no function symbols
and are domain-restricted but supports extensions including built-in functions
as well as cardinality and weight constraints. On top of this core engine more
involved s... |
E-RES: A System for Reasoning about Actions, Events and Observations | E-RES is a system that implements the Language E, a logic for reasoning about
narratives of action occurrences and observations. E's semantics is
model-theoretic, but this implementation is based on a sound and complete
reformulation of E in terms of argumentation, and uses general computational
techniques of argumenta... |
QUIP - A Tool for Computing Nonmonotonic Reasoning Tasks | In this paper, we outline the prototype of an automated inference tool,
called QUIP, which provides a uniform implementation for several nonmonotonic
reasoning formalisms. The theoretical basis of QUIP is derived from well-known
results about the computational complexity of nonmonotonic logics and exploits
a representa... |
A Splitting Set Theorem for Epistemic Specifications | Over the past decade a considerable amount of research has been done to
expand logic programming languages to handle incomplete information. One such
language is the language of epistemic specifications. As is usual with logic
programming languages, the problem of answering queries is intractable in the
general case. F... |
DES: a Challenge Problem for Nonmonotonic Reasoning Systems | The US Data Encryption Standard, DES for short, is put forward as an
interesting benchmark problem for nonmonotonic reasoning systems because (i) it
provides a set of test cases of industrial relevance which shares features of
randomly generated problems and real-world problems, (ii) the representation of
DES using nor... |
Fages' Theorem and Answer Set Programming | We generalize a theorem by Francois Fages that describes the relationship
between the completion semantics and the answer set semantics for logic
programs with negation as failure. The study of this relationship is important
in connection with the emergence of answer set programming. Whenever the two
semantics are equi... |
On the tractable counting of theory models and its application to belief
revision and truth maintenance | We introduced decomposable negation normal form (DNNF) recently as a
tractable form of propositional theories, and provided a number of powerful
logical operations that can be performed on it in polynomial time. We also
presented an algorithm for compiling any conjunctive normal form (CNF) into
DNNF and provided a stru... |
BDD-based reasoning in the fluent calculus - first results | The paper reports on first preliminary results and insights gained in a
project aiming at implementing the fluent calculus using methods and techniques
based on binary decision diagrams. After reporting on an initial experiment
showing promising results we discuss our findings concerning various techniques
and heuristi... |
Planning with Incomplete Information | Planning is a natural domain of application for frameworks of reasoning about
actions and change. In this paper we study how one such framework, the Language
E, can form the basis for planning under (possibly) incomplete information. We
define two types of plans: weak and safe plans, and propose a planner, called
the E... |
Local Diagnosis | In an earlier work, we have presented operations of belief change which only
affect the relevant part of a belief base. In this paper, we propose the
application of the same strategy to the problem of model-based diangosis. We
first isolate the subset of the system description which is relevant for a
given observation ... |
A Consistency-Based Model for Belief Change: Preliminary Report | We present a general, consistency-based framework for belief change.
Informally, in revising K by A, we begin with A and incorporate as much of K as
consistently possible. Formally, a knowledge base K and sentence A are
expressed, via renaming propositions in K, in separate languages. Using a
maximization process, we a... |
SATEN: An Object-Oriented Web-Based Revision and Extraction Engine | SATEN is an object-oriented web-based extraction and belief revision engine.
It runs on any computer via a Java 1.1 enabled browser such as Netscape 4.
SATEN performs belief revision based on the AGM approach. The extraction and
belief revision reasoning engines operate on a user specified ranking of
information. One o... |
dcs: An Implementation of DATALOG with Constraints | Answer-set programming (ASP) has emerged recently as a viable programming
paradigm. We describe here an ASP system, DATALOG with constraints or DC, based
on non-monotonic logic. Informally, DC theories consist of propositional
clauses (constraints) and of Horn rules. The semantics is a simple and natural
extension of t... |
DATALOG with constraints - an answer-set programming system | Answer-set programming (ASP) has emerged recently as a viable programming
paradigm well attuned to search problems in AI, constraint satisfaction and
combinatorics. Propositional logic is, arguably, the simplest ASP system with
an intuitive semantics supporting direct modeling of problem constraints.
However, for some ... |
Some Remarks on Boolean Constraint Propagation | We study here the well-known propagation rules for Boolean constraints. First
we propose a simple notion of completeness for sets of such rules and establish
a completeness result. Then we show an equivalence in an appropriate sense
between Boolean constraint propagation and unit propagation, a form of
resolution for p... |
Conditional Plausibility Measures and Bayesian Networks | A general notion of algebraic conditional plausibility measures is defined.
Probability measures, ranking functions, possibility measures, and (under the
appropriate definitions) sets of probability measures can all be viewed as
defining algebraic conditional plausibility measures. It is shown that
algebraic conditiona... |
Constraint compiling into rules formalism constraint compiling into
rules formalism for dynamic CSPs computing | In this paper we present a rule based formalism for filtering variables
domains of constraints. This formalism is well adapted for solving dynamic CSP.
We take diagnosis as an instance problem to illustrate the use of these rules.
A diagnosis problem is seen like finding all the minimal sets of constraints to
be relaxe... |
Brainstorm/J: a Java Framework for Intelligent Agents | Despite the effort of many researchers in the area of multi-agent systems
(MAS) for designing and programming agents, a few years ago the research
community began to take into account that common features among different MAS
exists. Based on these common features, several tools have tackled the problem
of agent develop... |
On the relationship between fuzzy logic and four-valued relevance logic | In fuzzy propositional logic, to a proposition a partial truth in [0,1] is
assigned. It is well known that under certain circumstances, fuzzy logic
collapses to classical logic. In this paper, we will show that under dual
conditions, fuzzy logic collapses to four-valued (relevance) logic, where
propositions have truth-... |
Causes and Explanations: A Structural-Model Approach, Part I: Causes | We propose a new definition of actual cause, using structural equations to
model counterfactuals. We show that the definition yields a plausible and
elegant account of causation that handles well examples which have caused
problems for other definitions and resolves major difficulties in the
traditional account. |
Logic Programming Approaches for Representing and Solving Constraint
Satisfaction Problems: A Comparison | Many logic programming based approaches can be used to describe and solve
combinatorial search problems. On the one hand there is constraint logic
programming which computes a solution as an answer substitution to a query
containing the variables of the constraint satisfaction problem. On the other
hand there are syste... |
Multi-Channel Parallel Adaptation Theory for Rule Discovery | In this paper, we introduce a new machine learning theory based on
multi-channel parallel adaptation for rule discovery. This theory is
distinguished from the familiar parallel-distributed adaptation theory of
neural networks in terms of channel-based convergence to the target rules. We
show how to realize this theory ... |
A Constraint-Driven System for Contract Assembly | We present an approach for modelling the structure and coarse content of
legal documents with a view to providing automated support for the drafting of
contracts and contract database retrieval. The approach is designed to be
applicable where contract drafting is based on model-form contracts or on
existing examples of... |
Modelling Contractual Arguments | One influential approach to assessing the "goodness" of arguments is offered
by the Pragma-Dialectical school (p-d) (Eemeren & Grootendorst 1992). This can
be compared with Rhetorical Structure Theory (RST) (Mann & Thompson 1988), an
approach that originates in discourse analysis. In p-d terms an argument is
good if it... |
Information Integration and Computational Logic | Information Integration is a young and exciting field with enormous research
and commercial significance in the new world of the Information Society. It
stands at the crossroad of Databases and Artificial Intelligence requiring
novel techniques that bring together different methods from these fields.
Information from d... |
Enhancing Constraint Propagation with Composition Operators | Constraint propagation is a general algorithmic approach for pruning the
search space of a CSP. In a uniform way, K. R. Apt has defined a computation as
an iteration of reduction functions over a domain. He has also demonstrated the
need for integrating static properties of reduction functions (commutativity
and semi-c... |
On Properties of Update Sequences Based on Causal Rejection | We consider an approach to update nonmonotonic knowledge bases represented as
extended logic programs under answer set semantics. New information is
incorporated into the current knowledge base subject to a causal rejection
principle enforcing that, in case of conflicts, more recent rules are preferred
and older rules ... |
Gradient-based Reinforcement Planning in Policy-Search Methods | We introduce a learning method called ``gradient-based reinforcement
planning'' (GREP). Unlike traditional DP methods that improve their policy
backwards in time, GREP is a gradient-based method that plans ahead and
improves its policy before it actually acts in the environment. We derive
formulas for the exact policy ... |
Rational Competitive Analysis | Much work in computer science has adopted competitive analysis as a tool for
decision making under uncertainty. In this work we extend competitive analysis
to the context of multi-agent systems. Unlike classical competitive analysis
where the behavior of an agent's environment is taken to be arbitrary, we
consider the ... |
A theory of experiment | This article aims at clarifying the language and practice of scientific
experiment, mainly by hooking observability on calculability. |
Nonmonotonic Reasoning, Preferential Models and Cumulative Logics | Many systems that exhibit nonmonotonic behavior have been described and
studied already in the literature. The general notion of nonmonotonic
reasoning, though, has almost always been described only negatively, by the
property it does not enjoy, i.e. monotonicity. We study here general patterns
of nonmonotonic reasonin... |
What does a conditional knowledge base entail? | This paper presents a logical approach to nonmonotonic reasoning based on the
notion of a nonmonotonic consequence relation. A conditional knowledge base,
consisting of a set of conditional assertions of the type "if ... then ...",
represents the explicit defeasible knowledge an agent has about the way the
world genera... |
A note on Darwiche and Pearl | It is shown that Darwiche and Pearl's postulates imply an interesting
property, not noticed by the authors. |
Distance Semantics for Belief Revision | A vast and interesting family of natural semantics for belief revision is
defined. Suppose one is given a distance d between any two models. One may then
define the revision of a theory K by a formula a as the theory defined by the
set of all those models of a that are closest, by d, to the set of models of K.
This fam... |
Preferred History Semantics for Iterated Updates | We give a semantics to iterated update by a preference relation on possible
developments. An iterated update is a sequence of formulas, giving (incomplete)
information about successive states of the world. A development is a sequence
of models, describing a possible trajectory through time. We assume a principle
of ine... |
Nonmonotonic inference operations | A. Tarski proposed the study of infinitary consequence operations as the
central topic of mathematical logic. He considered monotonicity to be a
property of all such operations. In this paper, we weaken the monotonicity
requirement and consider more general operations, inference operations. These
operations describe th... |
The logical meaning of Expansion | The Expansion property considered by researchers in Social Choice is shown to
correspond to a logical property of nonmonotonic consequence relations that is
the {\em pure}, i.e., not involving connectives, version of a previously known
weak rationality condition. The assumption that the union of two definable sets
of m... |
Another perspective on Default Reasoning | The lexicographic closure of any given finite set D of normal defaults is
defined. A conditional assertion "if a then b" is in this lexicographic closure
if, given the defaults D and the fact a, one would conclude b. The
lexicographic closure is essentially a rational extension of D, and of its
rational closure, define... |
Deductive Nonmonotonic Inference Operations: Antitonic Representations | We provide a characterization of those nonmonotonic inference operations C
for which C(X) may be described as the set of all logical consequences of X
together with some set of additional assumptions S(X) that depends
anti-monotonically on X (i.e., X is a subset of Y implies that S(Y) is a subset
of S(X)). The operatio... |
Stereotypical Reasoning: Logical Properties | Stereotypical reasoning assumes that the situation at hand is one of a kind
and that it enjoys the properties generally associated with that kind of
situation. It is one of the most basic forms of nonmonotonic reasoning. A
formal model for stereotypical reasoning is proposed and the logical properties
of this form of r... |
A Framework for Compiling Preferences in Logic Programs | We introduce a methodology and framework for expressing general preference
information in logic programming under the answer set semantics. An ordered
logic program is an extended logic program in which rules are named by unique
terms, and in which preferences among rules are given by a set of atoms of form
s < t where... |
Two results for proiritized logic programming | Prioritized default reasoning has illustrated its rich expressiveness and
flexibility in knowledge representation and reasoning. However, many important
aspects of prioritized default reasoning have yet to be thoroughly explored. In
this paper, we investigate two properties of prioritized logic programs in the
context ... |
Belief Revision and Rational Inference | The (extended) AGM postulates for belief revision seem to deal with the
revision of a given theory K by an arbitrary formula, but not to constrain the
revisions of two different theories by the same formula. A new postulate is
proposed and compared with other similar postulates that have been proposed in
the literature... |
Ultimate approximations in nonmonotonic knowledge representation systems | We study fixpoints of operators on lattices. To this end we introduce the
notion of an approximation of an operator. We order approximations by means of
a precision ordering. We show that each lattice operator O has a unique most
precise or ultimate approximation. We demonstrate that fixpoints of this
ultimate approxim... |
Handling Defeasibilities in Action Domains | Representing defeasibility is an important issue in common sense reasoning.
In reasoning about action and change, this issue becomes more difficult because
domain and action related defeasible information may conflict with general
inertia rules. Furthermore, different types of defeasible information may also
interfere ... |
Anticipatory Guidance of Plot | An anticipatory system for guiding plot development in interactive narratives
is described. The executable model is a finite automaton that provides the
implemented system with a look-ahead. The identification of undesirable future
states in the model is used to guide the player, in a transparent manner. In
this way, t... |
Abduction, ASP and Open Logic Programs | Open logic programs and open entailment have been recently proposed as an
abstract framework for the verification of incomplete specifications based upon
normal logic programs and the stable model semantics. There are obvious
analogies between open predicates and abducible predicates. However, despite
superficial simil... |
Domain-Dependent Knowledge in Answer Set Planning | In this paper we consider three different kinds of domain-dependent control
knowledge (temporal, procedural and HTN-based) that are useful in planning. Our
approach is declarative and relies on the language of logic programming with
answer set semantics (AnsProlog*). AnsProlog* is designed to plan without
control knowl... |
"Minimal defence": a refinement of the preferred semantics for
argumentation frameworks | Dung's abstract framework for argumentation enables a study of the
interactions between arguments based solely on an ``attack'' binary relation on
the set of arguments. Various ways to solve conflicts between contradictory
pieces of information have been proposed in the context of argumentation,
nonmonotonic reasoning ... |
Two Representations for Iterative Non-prioritized Change | We address a general representation problem for belief change, and describe
two interrelated representations for iterative non-prioritized change: a
logical representation in terms of persistent epistemic states, and a
constructive representation in terms of flocks of bases. |
Collective Argumentation | An extension of an abstract argumentation framework, called collective
argumentation, is introduced in which the attack relation is defined directly
among sets of arguments. The extension turns out to be suitable, in particular,
for representing semantics of disjunctive logic programs. Two special kinds of
collective a... |
Logic Programming with Ordered Disjunction | Logic programs with ordered disjunction (LPODs) combine ideas underlying
Qualitative Choice Logic (Brewka et al. KR 2002) and answer set programming.
Logic programming under answer set semantics is extended with a new connective
called ordered disjunction. The new connective allows us to represent
alternative, ranked o... |
Compilation of Propositional Weighted Bases | In this paper, we investigate the extent to which knowledge compilation can
be used to improve inference from propositional weighted bases. We present a
general notion of compilation of a weighted base that is parametrized by any
equivalence--preserving compilation function. Both negative and positive
results are prese... |
Modeling Complex Domains of Actions and Change | This paper studies the problem of modeling complex domains of actions and
change within high-level action description languages. We investigate two main
issues of concern: (a) can we represent complex domains that capture together
different problems such as ramifications, non-determinism and concurrency of
actions, at ... |
Value Based Argumentation Frameworks | This paper introduces the notion of value-based argumentation frameworks, an
extension of the standard argumentation frameworks proposed by Dung, which are
able toshow how rational decision is possible in cases where arguments derive
their force from the social values their acceptance would promote. |
Preferred well-founded semantics for logic programming by alternating
fixpoints: Preliminary report | We analyze the problem of defining well-founded semantics for ordered logic
programs within a general framework based on alternating fixpoint theory. We
start by showing that generalizations of existing answer set approaches to
preference are too weak in the setting of well-founded semantics. We then
specify some infor... |
Embedding Default Logic in Propositional Argumentation Systems | In this paper we present a transformation of finite propositional default
theories into so-called propositional argumentation systems. This
transformation allows to characterize all notions of Reiter's default logic in
the framework of argumentation systems. As a consequence, computing extensions,
or determining wether... |
On the existence and multiplicity of extensions in dialectical
argumentation | In the present paper, the existence and multiplicity problems of extensions
are addressed. The focus is on extension of the stable type. The main result of
the paper is an elegant characterization of the existence and multiplicity of
extensions in terms of the notion of dialectical justification, a close cousin
of the ... |
Nonmonotonic Probabilistic Logics between Model-Theoretic Probabilistic
Logic and Probabilistic Logic under Coherence | Recently, it has been shown that probabilistic entailment under coherence is
weaker than model-theoretic probabilistic entailment. Moreover, probabilistic
entailment under coherence is a generalization of default entailment in System
P. In this paper, we continue this line of research by presenting probabilistic
genera... |
Evaluating Defaults | We seek to find normative criteria of adequacy for nonmonotonic logic similar
to the criterion of validity for deductive logic. Rather than stipulating that
the conclusion of an inference be true in all models in which the premises are
true, we require that the conclusion of a nonmonotonic inference be true in
``almost... |
Linking Makinson and Kraus-Lehmann-Magidor preferential entailments | About ten years ago, various notions of preferential entailment have been
introduced. The main reference is a paper by Kraus, Lehmann and Magidor (KLM),
one of the main competitor being a more general version defined by Makinson
(MAK). These two versions have already been compared, but it is time to revisit
these compa... |
Knowledge Representation | This work analyses main features that should be present in knowledge
representation. It suggests a model for representation and a way to implement
this model in software. Representation takes care of both low-level sensor
information and high-level concepts. |
Causes and Explanations: A Structural-Model Approach. Part II:
Explanations | We propose new definitions of (causal) explanation, using structural
equations to model counterfactuals. The definition is based on the notion of
actual cause, as defined and motivated in a companion paper. Essentially, an
explanation is a fact that is not known for certain but, if found to be true,
would constitute an... |
Reasoning about Evolving Nonmonotonic Knowledge Bases | Recently, several approaches to updating knowledge bases modeled as extended
logic programs have been introduced, ranging from basic methods to incorporate
(sequences of) sets of rules into a logic program, to more elaborate methods
which use an update policy for specifying how updates must be incorporated. In
this pap... |
A Comparison of Different Cognitive Paradigms Using Simple Animats in a
Virtual Laboratory, with Implications to the Notion of Cognition | In this thesis I present a virtual laboratory which implements five different
models for controlling animats: a rule-based system, a behaviour-based system,
a concept-based system, a neural network, and a Braitenberg architecture.
Through different experiments, I compare the performance of the models and
conclude that ... |
Revising Partially Ordered Beliefs | This paper deals with the revision of partially ordered beliefs. It proposes
a semantic representation of epistemic states by partial pre-orders on
interpretations and a syntactic representation by partially ordered belief
bases. Two revision operations, the revision stemming from the history of
observations and the po... |
Can the whole brain be simpler than its "parts"? | This is the first in a series of connected papers discussing the problem of a
dynamically reconfigurable universal learning neurocomputer that could serve as
a computational model for the whole human brain. The whole series is entitled
"The Brain Zero Project. My Brain as a Dynamically Reconfigurable Universal
Learning... |
Adaptive Development of Koncepts in Virtual Animats: Insights into the
Development of Knowledge | As a part of our effort for studying the evolution and development of
cognition, we present results derived from synthetic experimentations in a
virtual laboratory where animats develop koncepts adaptively and ground their
meaning through action. We introduce the term "koncept" to avoid confusions and
ambiguity derived... |
Dynamic Adjustment of the Motivation Degree in an Action Selection
Mechanism | This paper presents a model for dynamic adjustment of the motivation degree,
using a reinforcement learning approach, in an action selection mechanism
previously developed by the authors. The learning takes place in the
modification of a parameter of the model of combination of internal and
external stimuli. Experiment... |
Action Selection Properties in a Software Simulated Agent | This article analyses the properties of the Internal Behaviour network, an
action selection mechanism previously proposed by the authors, with the aid of
a simulation developed for such ends. A brief review of the Internal Behaviour
network is followed by the explanation of the implementation of the simulation.
Then, e... |
A Model for Combination of External and Internal Stimuli in the Action
Selection of an Autonomous Agent | This paper proposes a model for combination of external and internal stimuli
for the action selection in an autonomous agent, based in an action selection
mechanism previously proposed by the authors. This combination model includes
additive and multiplicative elements, which allows to incorporate new
properties, which... |
Searching for Plannable Domains can Speed up Reinforcement Learning | Reinforcement learning (RL) involves sequential decision making in uncertain
environments. The aim of the decision-making agent is to maximize the benefit
of acting in its environment over an extended period of time. Finding an
optimal policy in RL may be very slow. To speed up learning, one often used
solution is the ... |
Temporal plannability by variance of the episode length | Optimization of decision problems in stochastic environments is usually
concerned with maximizing the probability of achieving the goal and minimizing
the expected episode length. For interacting agents in time-critical
applications, learning of the possibility of scheduling of subtasks (events) or
the full task is an ... |
Comparisons and Computation of Well-founded Semantics for Disjunctive
Logic Programs | Much work has been done on extending the well-founded semantics to general
disjunctive logic programs and various approaches have been proposed. However,
these semantics are different from each other and no consensus is reached about
which semantics is the most intended. In this paper we look at disjunctive
well-founde... |
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