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19,102
Optimal Decomposition of Belief Networks
cs.AI
In this paper, optimum decomposition of belief networks is discussed. Some methods of decomposition are examined and a new method - the method of Minimum Total Number of States (MTNS) - is proposed. The problem of optimum belief network decomposition under our framework, as under all the other frameworks, is shown to b...
computer science
19,103
Pruning Bayesian Networks for Efficient Computation
cs.AI
This paper analyzes the circumstances under which Bayesian networks can be pruned in order to reduce computational complexity without altering the computation for variables of interest. Given a problem instance which consists of a query and evidence for a set of nodes in the network, it is possible to delete portions o...
computer science
19,104
On Heuristics for Finding Loop Cutsets in Multiply-Connected Belief Networks
cs.AI
We introduce a new heuristic algorithm for the problem of finding minimum size loop cutsets in multiply connected belief networks. We compare this algorithm to that proposed in [Suemmondt and Cooper, 1988]. We provide lower bounds on the performance of these algorithms with respect to one another and with respect to op...
computer science
19,105
A Combination of Cutset Conditioning with Clique-Tree Propagation in the Pathfinder System
cs.AI
Cutset conditioning and clique-tree propagation are two popular methods for performing exact probabilistic inference in Bayesian belief networks. Cutset conditioning is based on decomposition of a subset of network nodes, whereas clique-tree propagation depends on aggregation of nodes. We describe a means to combine cu...
computer science
19,106
Possibility as Similarity: the Semantics of Fuzzy Logic
cs.AI
This paper addresses fundamental issues on the nature of the concepts and structures of fuzzy logic, focusing, in particular, on the conceptual and functional differences that exist between probabilistic and possibilistic approaches. A semantic model provides the basic framework to define possibilistic structures and c...
computer science
19,107
Integrating Case-Based and Rule-Based Reasoning: the Possibilistic Connection
cs.AI
Rule based reasoning (RBR) and case based reasoning (CBR) have emerged as two important and complementary reasoning methodologies in artificial intelligence (Al). For problem solving in complex, real world situations, it is useful to integrate RBR and CBR. This paper presents an approach to achieve a compact and seamle...
computer science
19,108
Credibility Discounting in the Theory of Approximate Reasoning
cs.AI
We are concerned with the problem of introducing credibility type information into reasoning systems. The concept of credibility allows us to discount information provided by agents. An important characteristic of this kind of procedure is that a complete lack of credibility rather than resulting in the negation of the...
computer science
19,109
Updating with Belief Functions, Ordinal Conditioning Functions and Possibility Measures
cs.AI
This paper discusses how a measure of uncertainty representing a state of knowledge can be updated when a new information, which may be pervaded with uncertainty, becomes available. This problem is considered in various framework, namely: Shafer's evidence theory, Zadeh's possibility theory, Spohn's theory of epistemic...
computer science
19,110
The Transferable Belief Model and Other Interpretations of Dempster-Shafer's Model
cs.AI
Dempster-Shafer's model aims at quantifying degrees of belief But there are so many interpretations of Dempster-Shafer's theory in the literature that it seems useful to present the various contenders in order to clarify their respective positions. We shall successively consider the classical probability model, the upp...
computer science
19,111
Valuation-Based Systems for Discrete Optimization
cs.AI
This paper describes valuation-based systems for representing and solving discrete optimization problems. In valuation-based systems, we represent information in an optimization problem using variables, sample spaces of variables, a set of values, and functions that map sample spaces of sets of variables to the set of ...
computer science
19,112
Computational Aspects of the Mobius Transform
cs.AI
In this paper we associate with every (directed) graph G a transformation called the Mobius transformation of the graph G. The Mobius transformation of the graph (O) is of major significance for Dempster-Shafer theory of evidence. However, because it is computationally very heavy, the Mobius transformation together wit...
computer science
19,113
Using Dempster-Shafer Theory in Knowledge Representation
cs.AI
In this paper, we suggest marrying Dempster-Shafer (DS) theory with Knowledge Representation (KR). Born out of this marriage is the definition of "Dempster-Shafer Belief Bases", abstract data types representing uncertain knowledge that use DS theory for representing strength of belief about our knowledge, and the lingu...
computer science
19,114
A Hierarchical Approach to Designing Approximate Reasoning-Based Controllers for Dynamic Physical Systems
cs.AI
This paper presents a new technique for the design of approximate reasoning based controllers for dynamic physical systems with interacting goals. In this approach, goals are achieved based on a hierarchy defined by a control knowledge base and remain highly interactive during the execution of the control task. The app...
computer science
19,115
Evidence Combination and Reasoning and Its Application to Real-World Problem-Solving
cs.AI
In this paper a new mathematical procedure is presented for combining different pieces of evidence which are represented in the interval form to reflect our knowledge about the truth of a hypothesis. Evidences may be correlated to each other (dependent evidences) or conflicting in supports (conflicting evidences). Firs...
computer science
19,116
On Some Equivalence Relations between Incidence Calculus and Dempster-Shafer Theory of Evidence
cs.AI
Incidence Calculus and Dempster-Shafer Theory of Evidence are both theories to describe agents' degrees of belief in propositions, thus being appropriate to represent uncertainty in reasoning systems. This paper presents a straightforward equivalence proof between some special cases of these theories.
computer science
19,117
Using Belief Functions for Uncertainty Management and Knowledge Acquisition: An Expert Application
cs.AI
This paper describes recent work on an ongoing project in medical diagnosis at the University of Guelph. A domain on which experts are not very good at pinpointing a single disease outcome is explored. On-line medical data is available over a relatively short period of time. Belief Functions (Dempster-Shafer theory) ar...
computer science
19,118
An Architecture for Probabilistic Concept-Based Information Retrieval
cs.AI
While concept-based methods for information retrieval can provide improved performance over more conventional techniques, they require large amounts of effort to acquire the concepts and their qualitative and quantitative relationships. This paper discusses an architecture for probabilistic concept-based information re...
computer science
19,119
Amplitude-Based Approach to Evidence Accumulation
cs.AI
We point out the need to use probability amplitudes rather than probabilities to model evidence accumulation in decision processes involving real physical sensors. Optical information processing systems are given as typical examples of systems that naturally gather evidence in this manner. We derive a new, amplitude-ba...
computer science
19,120
A Probabilistic Reasoning Environment
cs.AI
A framework is presented for a computational theory of probabilistic argument. The Probabilistic Reasoning Environment encodes knowledge at three levels. At the deepest level are a set of schemata encoding the system's domain knowledge. This knowledge is used to build a set of second-level arguments, which are structur...
computer science
19,121
On Non-monotonic Conditional Reasoning
cs.AI
This note is concerned with a formal analysis of the problem of non-monotonic reasoning in intelligent systems, especially when the uncertainty is taken into account in a quantitative way. A firm connection between logic and probability is established by introducing conditioning notions by means of formal structures th...
computer science
19,122
Decisions with Limited Observations over a Finite Product Space: the Klir Effect
cs.AI
Probability estimation by maximum entropy reconstruction of an initial relative frequency estimate from its projection onto a hypergraph model of the approximate conditional independence relations exhibited by it is investigated. The results of this study suggest that use of this estimation technique may improve the qu...
computer science
19,123
Fine-Grained Decision-Theoretic Search Control
cs.AI
Decision-theoretic control of search has previously used as its basic unit. of computation the generation and evaluation of a complete set of successors. Although this simplifies analysis, it results in some lost opportunities for pruning and satisficing. This paper therefore extends the analysis of the value of comput...
computer science
19,124
Rules, Belief Functions and Default Logic
cs.AI
This paper describes a natural framework for rules, based on belief functions, which includes a repre- sentation of numerical rules, default rules and rules allowing and rules not allowing contraposition. In particular it justifies the use of the Dempster-Shafer Theory for representing a particular class of rules, Beli...
computer science
19,125
Combination of Evidence Using the Principle of Minimum Information Gain
cs.AI
One of the most important aspects in any treatment of uncertain information is the rule of combination for updating the degrees of uncertainty. The theory of belief functions uses the Dempster rule to combine two belief functions defined by independent bodies of evidence. However, with limited dependency information ab...
computer science
19,126
Probabilistic Evaluation of Candidates and Symptom Clustering for Multidisorder Diagnosis
cs.AI
This paper derives a formula for computing the conditional probability of a set of candidates, where a candidate is a set of disorders that explain a given set of positive findings. Such candidate sets are produced by a recent method for multidisorder diagnosis called symptom clustering. A symptom clustering represents...
computer science
19,127
Extending Term Subsumption systems for Uncertainty Management
cs.AI
A major difficulty in developing and maintaining very large knowledge bases originates from the variety of forms in which knowledge is made available to the KB builder. The objective of this research is to bring together two complementary knowledge representation schemes: term subsumption languages, which represent and...
computer science
19,128
Refinement and Coarsening of Bayesian Networks
cs.AI
In almost all situation assessment problems, it is useful to dynamically contract and expand the states under consideration as assessment proceeds. Contraction is most often used to combine similar events or low probability events together in order to reduce computation. Expansion is most often used to make distinction...
computer science
19,129
Second Order Probabilities for Uncertain and Conflicting Evidence
cs.AI
In this paper the elicitation of probabilities from human experts is considered as a measurement process, which may be disturbed by random 'measurement noise'. Using Bayesian concepts a second order probability distribution is derived reflecting the uncertainty of the input probabilities. The algorithm is based on an a...
computer science
19,130
Computing Probability Intervals Under Independency Constraints
cs.AI
Many AI researchers argue that probability theory is only capable of dealing with uncertainty in situations where a full specification of a joint probability distribution is available, and conclude that it is not suitable for application in knowledge-based systems. Probability intervals, however, constitute a means for...
computer science
19,131
An Empirical Analysis of Likelihood-Weighting Simulation on a Large, Multiply-Connected Belief Network
cs.AI
We analyzed the convergence properties of likelihood- weighting algorithms on a two-level, multiply connected, belief-network representation of the QMR knowledge base of internal medicine. Specifically, on two difficult diagnostic cases, we examined the effects of Markov blanket scoring, importance sampling, demonstrat...
computer science
19,132
Towards a Normative Theory of Scientific Evidence
cs.AI
A scientific reasoning system makes decisions using objective evidence in the form of independent experimental trials, propositional axioms, and constraints on the probabilities of events. As a first step towards this goal, we propose a system that derives probability intervals from objective evidence in those forms. O...
computer science
19,133
A Model for Non-Monotonic Reasoning Using Dempster's Rule
cs.AI
Considerable attention has been given to the problem of non-monotonic reasoning in a belief function framework. Earlier work (M. Ginsberg) proposed solutions introducing meta-rules which recognized conditional independencies in a probabilistic sense. More recently an e-calculus formulation of default reasoning (J. Pear...
computer science
19,134
Default Reasoning and the Transferable Belief Model
cs.AI
Inappropriate use of Dempster's rule of combination has led some authors to reject the Dempster-Shafer model, arguing that it leads to supposedly unacceptable conclusions when defaults are involved. A most classic example is about the penguin Tweety. This paper will successively present: the origin of the miss-manageme...
computer science
19,135
Separable and transitive graphoids
cs.AI
We examine three probabilistic formulations of the sentence a and b are totally unrelated with respect to a given set of variables U. First, two variables a and b are totally independent if they are independent given any value of any subset of the variables in U. Second, two variables are totally uncoupled if U can be ...
computer science
19,136
Analysis in HUGIN of Data Conflict
cs.AI
After a brief introduction to causal probabilistic networks and the HUGIN approach, the problem of conflicting data is discussed. A measure of conflict is defined, and it is used in the medical diagnostic system MUNIN. Finally, it is discussed how to distinguish between conflicting data and a rare case.
computer science
19,137
Computing Datalog Rewritings beyond Horn Ontologies
cs.AI
Rewriting-based approaches for answering queries over an OWL 2 DL ontology have so far been developed mainly for Horn fragments of OWL 2 DL. In this paper, we study the possibilities of answering queries over non-Horn ontologies using datalog rewritings. We prove that this is impossible in general even for very simple ...
computer science
19,138
Lp : A Logic for Statistical Information
cs.AI
This extended abstract presents a logic, called Lp, that is capable of representing and reasoning with a wide variety of both qualitative and quantitative statistical information. The advantage of this logical formalism is that it offers a declarative representation of statistical knowledge; knowledge represented in th...
computer science
19,139
Map Learning with Indistinguishable Locations
cs.AI
Nearly all spatial reasoning problems involve uncertainty of one sort or another. Uncertainty arises due to the inaccuracies of sensors used in measuring distances and angles. We refer to this as directional uncertainty. Uncertainty also arises in combining spatial information when one location is mistakenly identified...
computer science
19,140
Temporal Reasoning with Probabilities
cs.AI
In this paper we explore representations of temporal knowledge based upon the formalism of Causal Probabilistic Networks (CPNs). Two different ?continuous-time? representations are proposed. In the first, the CPN includes variables representing ?event-occurrence times?, possibly on different time scales, and variables ...
computer science
19,141
Now that I Have a Good Theory of Uncertainty, What Else Do I Need?
cs.AI
Rather than discussing the isolated merits of a nominative theory of uncertainty, this paper focuses on a class of problems, referred to as Dynamic Classification Problem (DCP), which requires the integration of many theories, including a prescriptive theory of uncertainty. We start by analyzing the Dynamic Classificat...
computer science
19,142
Uncertainty and Incompleteness
cs.AI
Two major difficulties in using default logics are their intractability and the problem of selecting among multiple extensions. We propose an approach to these problems based on integrating nommonotonic reasoning with plausible reasoning based on triangular norms. A previously proposed system for reasoning with uncerta...
computer science
19,143
BaRT: A Bayesian Reasoning Tool for Knowledge Based Systems
cs.AI
As the technology for building knowledge based systems has matured, important lessons have been learned about the relationship between the architecture of a system and the nature of the problems it is intended to solve. We are implementing a knowledge engineering tool called BART that is designed with these lessons in ...
computer science
19,144
Plan Recognition in Stories and in Life
cs.AI
Plan recognition does not work the same way in stories and in "real life" (people tend to jump to conclusions more in stories). We present a theory of this, for the particular case of how objects in stories (or in life) influence plan recognition decisions. We provide a Bayesian network formalization of a simple first-...
computer science
19,145
An Empirical Evaluation of a Randomized Algorithm for Probabilistic Inference
cs.AI
In recent years, researchers in decision analysis and artificial intelligence (Al) have used Bayesian belief networks to build models of expert opinion. Using standard methods drawn from the theory of computational complexity, workers in the field have shown that the problem of probabilistic inference in belief network...
computer science
19,146
Decision Making "Biases" and Support for Assumption-Based Higher-Order Reasoning
cs.AI
Unaided human decision making appears to systematically violate consistency constraints imposed by normative theories; these biases in turn appear to justify the application of formal decision-analytic models. It is argued that both claims are wrong. In particular, we will argue that the "confirmation bias" is premised...
computer science
19,147
Automated Reasoning Using Possibilistic Logic: Semantics, Belief Revision and Variable Certainty Weights
cs.AI
In this paper an approach to automated deduction under uncertainty,based on possibilistic logic, is proposed ; for that purpose we deal with clauses weighted by a degree which is a lower bound of a necessity or a possibility measure, according to the nature of the uncertainty. Two resolution rules are used for coping w...
computer science
19,148
How Much More Probable is "Much More Probable"? Verbal Expressions for Probability Updates
cs.AI
Bayesian inference systems should be able to explain their reasoning to users, translating from numerical to natural language. Previous empirical work has investigated the correspondence between absolute probabilities and linguistic phrases. This study extends that work to the correspondence between changes in probabil...
computer science
19,149
Positive and Negative Explanations of Uncertain Reasoning in the Framework of Possibility Theory
cs.AI
This paper presents an approach for developing the explanation capabilities of rule-based expert systems managing imprecise and uncertain knowledge. The treatment of uncertainty takes place in the framework of possibility theory where the available information concerning the value of a logical or numerical variable is ...
computer science
19,150
Interval Influence Diagrams
cs.AI
We describe a mechanism for performing probabilistic reasoning in influence diagrams using interval rather than point valued probabilities. We derive the procedures for node removal (corresponding to conditional expectation) and arc reversal (corresponding to Bayesian conditioning) in influence diagrams where lower bou...
computer science
19,151
Weighing and Integrating Evidence for Stochastic Simulation in Bayesian Networks
cs.AI
Stochastic simulation approaches perform probabilistic inference in Bayesian networks by estimating the probability of an event based on the frequency that the event occurs in a set of simulation trials. This paper describes the evidence weighting mechanism, for augmenting the logic sampling stochastic simulation algor...
computer science
19,152
d-Separation: From Theorems to Algorithms
cs.AI
An efficient algorithm is developed that identifies all independencies implied by the topology of a Bayesian network. Its correctness and maximality stems from the soundness and completeness of d-separation with respect to probability theory. The algorithm runs in time O (l E l) where E is the number of edges in the ne...
computer science
19,153
The Effects of Perfect and Sample Information on Fuzzy Utilities in Decision-Making
cs.AI
In this paper, we first consider a Bayesian framework and model the "utility function" in terms of fuzzy random variables. On the basis of this model, we define the "prior (fuzzy) expected utility" associated with each action, and the corresponding "posterior (fuzzy) expected utility given sample information from a ran...
computer science
19,154
Deciding Consistency of Databases Containing Defeasible and Strict Information
cs.AI
We propose a norm of consistency for a mixed set of defeasible and strict sentences, based on a probabilistic semantics. This norm establishes a clear distinction between knowledge bases depicting exceptions and those containing outright contradictions. We then define a notion of entailment based also on probabilistic ...
computer science
19,155
The Relationship between Knowledge, Belief and Certainty
cs.AI
We consider the relation between knowledge and certainty, where a fact is known if it is true at all worlds an agent considers possible and is certain if it holds with probability 1. We identify certainty with probabilistic belief. We show that if we assume one fixed probability assignment, then the logic KD45, which h...
computer science
19,156
Heuristic Search as Evidential Reasoning
cs.AI
BPS, the Bayesian Problem Solver, applies probabilistic inference and decision-theoretic control to flexible, resource-constrained problem-solving. This paper focuses on the Bayesian inference mechanism in BPS, and contrasts it with those of traditional heuristic search techniques. By performing sound inference, BPS ca...
computer science
19,157
The Compilation of Decision Models
cs.AI
We introduce and analyze the problem of the compilation of decision models from a decision-theoretic perspective. The techniques described allow us to evaluate various configurations of compiled knowledge given the nature of evidential relationships in a domain, the utilities associated with alternative actions, the co...
computer science
19,158
A Tractable Inference Algorithm for Diagnosing Multiple Diseases
cs.AI
We examine a probabilistic model for the diagnosis of multiple diseases. In the model, diseases and findings are represented as binary variables. Also, diseases are marginally independent, features are conditionally independent given disease instances, and diseases interact to produce findings via a noisy OR-gate. An a...
computer science
19,159
Bounded Conditioning: Flexible Inference for Decisions under Scarce Resources
cs.AI
We introduce a graceful approach to probabilistic inference called bounded conditioning. Bounded conditioning monotonically refines the bounds on posterior probabilities in a belief network with computation, and converges on final probabilities of interest with the allocation of a complete resource fraction. The approa...
computer science
19,160
Hierarchical Evidence Accumulation in the Pseiki System and Experiments in Model-Driven Mobile Robot Navigation
cs.AI
In this paper, we will review the process of evidence accumulation in the PSEIKI system for expectation-driven interpretation of images of 3-D scenes. Expectations are presented to PSEIKI as a geometrical hierarchy of abstractions. PSEIKI's job is then to construct abstraction hierarchies in the perceived image taking ...
computer science
19,161
A Decision-Theoretic Model for Using Scientific Data
cs.AI
Many Artificial Intelligence systems depend on the agent's updating its beliefs about the world on the basis of experience. Experiments constitute one type of experience, so scientific methodology offers a natural environment for examining the issues attendant to using this class of evidence. This paper presents a fram...
computer science
19,162
When Should a Decision Maker Ignore the Advice of a Decision Aid?
cs.AI
This paper argues that the principal difference between decision aids and most other types of information systems is the greater reliance of decision aids on fallible algorithms--algorithms that sometimes generate incorrect advice. It is shown that interactive problem solving with a decision aid that is based on a fall...
computer science
19,163
Inference Policies
cs.AI
It is suggested that an AI inference system should reflect an inference policy that is tailored to the domain of problems to which it is applied -- and furthermore that an inference policy need not conform to any general theory of rational inference or induction. We note, for instance, that Bayesian reasoning about the...
computer science
19,164
Defeasible Decisions: What the Proposal is and isn't
cs.AI
In two recent papers, I have proposed a description of decision analysis that differs from the Bayesian picture painted by Savage, Jeffrey and other classic authors. Response to this view has been either overly enthusiastic or unduly pessimistic. In this paper I try to place the idea in its proper place, which must be ...
computer science
19,165
Experiments Using Belief Functions and Weights of Evidence incorporating Statistical Data and Expert Opinions
cs.AI
This paper presents some ideas and results of using uncertainty management methods in the presence of data in preference to other statistical and machine learning methods. A medical domain is used as a test-bed with data available from a large hospital database system which collects symptom and outcome information abou...
computer science
19,166
Shootout-89: A Comparative Evaluation of Knowledge-based Systems that Forecast Severe Weather
cs.AI
During the summer of 1989, the Forecast Systems Laboratory of the National Oceanic and Atmospheric Administration sponsored an evaluation of artificial intelligence-based systems that forecast severe convective storms. The evaluation experiment, called Shootout-89, took place in Boulder, and focussed on storms over the...
computer science
19,167
Conditioning on Disjunctive Knowledge: Defaults and Probabilities
cs.AI
Many writers have observed that default logics appear to contain the "lottery paradox" of probability theory. This arises when a default "proof by contradiction" lets us conclude that a typical X is not a Y where Y is an unusual subclass of X. We show that there is a similar problem with default "proof by cases" and co...
computer science
19,168
Maximum Uncertainty Procedures for Interval-Valued Probability Distributions
cs.AI
Measures of uncertainty and divergence are introduced for interval-valued probability distributions and are shown to have desirable mathematical properties. A maximum uncertainty inference procedure for marginal interval distributions is presented. A technique for reconstruction of interval distributions from projectio...
computer science
19,169
A Logical Interpretation of Dempster-Shafer Theory, with Application to Visual Recognition
cs.AI
We formulate Dempster Shafer Belief functions in terms of Propositional Logic using the implicit notion of provability underlying Dempster Shafer Theory. Given a set of propositional clauses, assigning weights to certain propositional literals enables the Belief functions to be explicitly computed using Network Reliabi...
computer science
19,170
Strategies for Generating Micro Explanations for Bayesian Belief Networks
cs.AI
Bayesian Belief Networks have been largely overlooked by Expert Systems practitioners on the grounds that they do not correspond to the human inference mechanism. In this paper, we introduce an explanation mechanism designed to generate intuitive yet probabilistically sound explanations of inferences drawn by a Bayesia...
computer science
19,171
Evidence Absorption and Propagation through Evidence Reversals
cs.AI
The arc reversal/node reduction approach to probabilistic inference is extended to include the case of instantiated evidence by an operation called "evidence reversal." This not only provides a technique for computing posterior joint distributions on general belief networks, but also provides insight into the methods o...
computer science
19,172
Simulation Approaches to General Probabilistic Inference on Belief Networks
cs.AI
A number of algorithms have been developed to solve probabilistic inference problems on belief networks. These algorithms can be divided into two main groups: exact techniques which exploit the conditional independence revealed when the graph structure is relatively sparse, and probabilistic sampling techniques which e...
computer science
19,173
Decision under Uncertainty
cs.AI
We derive axiomatically the probability function that should be used to make decisions given any form of underlying uncertainty.
computer science
19,174
Freedom: A Measure of Second-order Uncertainty for Intervalic Probability Schemes
cs.AI
This paper discusses a new measure that is adaptable to certain intervalic probability frameworks, possibility theory, and belief theory. As such, it has the potential for wide use in knowledge engineering, expert systems, and related problems in the human sciences. This measure (denoted here by F) has been introduced ...
computer science
19,175
Assessment, Criticism and Improvement of Imprecise Subjective Probabilities for a Medical Expert System
cs.AI
Three paediatric cardiologists assessed nearly 1000 imprecise subjective conditional probabilities for a simple belief network representing congenital heart disease, and the quality of the assessments has been measured using prospective data on 200 babies. Quality has been assessed by a Brier scoring rule, which decomp...
computer science
19,176
Automated Construction of Sparse Bayesian Networks from Unstructured Probabilistic Models and Domain Information
cs.AI
An algorithm for automated construction of a sparse Bayesian network given an unstructured probabilistic model and causal domain information from an expert has been developed and implemented. The goal is to obtain a network that explicitly reveals as much information regarding conditional independence as possible. The ...
computer science
19,177
Making Decisions with Belief Functions
cs.AI
A primary motivation for reasoning under uncertainty is to derive decisions in the face of inconclusive evidence. However, Shafer's theory of belief functions, which explicitly represents the underconstrained nature of many reasoning problems, lacks a formal procedure for making decisions. Clearly, when sufficient info...
computer science
19,178
Efficient Parallel Estimation for Markov Random Fields
cs.AI
We present a new, deterministic, distributed MAP estimation algorithm for Markov Random Fields called Local Highest Confidence First (Local HCF). The algorithm has been applied to segmentation problems in computer vision and its performance compared with stochastic algorithms. The experiments show that Local HCF finds ...
computer science
19,179
Comparing Expert Systems Built Using Different Uncertain Inference Systems
cs.AI
This study compares the inherent intuitiveness or usability of the most prominent methods for managing uncertainty in expert systems, including those of EMYCIN, PROSPECTOR, Dempster-Shafer theory, fuzzy set theory, simplified probability theory (assuming marginal independence), and linear regression using probability e...
computer science
19,180
Directed Cycles in Belief Networks
cs.AI
The most difficult task in probabilistic reasoning may be handling directed cycles in belief networks. To the best knowledge of this author, there is no serious discussion of this problem at all in the literature of probabilistic reasoning so far.
computer science
19,181
Can Uncertainty Management be Realized in a Finite Totally Ordered Probability Algebra?
cs.AI
In this paper, the feasibility of using finite totally ordered probability models under Alelinnas's Theory of Probabilistic Logic [Aleliunas, 1988] is investigated. The general form of the probability algebra of these models is derived and the number of possible algebras with given size is deduced. Based on this analys...
computer science
19,182
Normalization and the Representation of Nonmonotonic Knowledge in the Theory of Evidence
cs.AI
We discuss the Dempster-Shafer theory of evidence. We introduce a concept of monotonicity which is related to the diminution of the range between belief and plausibility. We show that the accumulation of knowledge in this framework exhibits a nonmonotonic property. We show how the belief structure can be used to repres...
computer science
19,183
Probability Aggregates in Probability Answer Set Programming
cs.AI
Probability answer set programming is a declarative programming that has been shown effective for representing and reasoning about a variety of probability reasoning tasks. However, the lack of probability aggregates, e.g. {\em expected values}, in the language of disjunctive hybrid probability logic programs (DHPP) di...
computer science
19,184
Model-based Bayesian Reinforcement Learning for Dialogue Management
cs.AI
Reinforcement learning methods are increasingly used to optimise dialogue policies from experience. Most current techniques are model-free: they directly estimate the utility of various actions, without explicit model of the interaction dynamics. In this paper, we investigate an alternative strategy grounded in model-b...
computer science
19,185
Fuzzy Aggregates in Fuzzy Answer Set Programming
cs.AI
Fuzzy answer set programming is a declarative framework for representing and reasoning about knowledge in fuzzy environments. However, the unavailability of fuzzy aggregates in disjunctive fuzzy logic programs, DFLP, with fuzzy answer set semantics prohibits the natural and concise representation of many interesting pr...
computer science
19,186
The structure of Bayes nets for vision recognition
cs.AI
This paper is part of a study whose goal is to show the effciency of using Bayes networks to carry out model based vision calculations. [Binford et al. 1987] Recognition proceeds by drawing up a network model from the object's geometric and functional description that predicts the appearance of an object. Then this net...
computer science
19,187
Summary of A New Normative Theory of Probabilistic Logic
cs.AI
By probabilistic logic I mean a normative theory of belief that explains how a body of evidence affects one's degree of belief in a possible hypothesis. A new axiomatization of such a theory is presented which avoids a finite additivity axiom, yet which retains many useful inference rules. Many of the examples of this ...
computer science
19,188
Probability Distributions Over Possible Worlds
cs.AI
In Probabilistic Logic Nilsson uses the device of a probability distribution over a set of possible worlds to assign probabilities to the sentences of a logical language. In his paper Nilsson concentrated on inference and associated computational issues. This paper, on the other hand, examines the probabilistic semanti...
computer science
19,189
Hierarchical Evidence and Belief Functions
cs.AI
Dempster/Shafer (D/S) theory has been advocated as a way of representing incompleteness of evidence in a system's knowledge base. Methods now exist for propagating beliefs through chains of inference. This paper discusses how rules with attached beliefs, a common representation for knowledge in automated reasoning syst...
computer science
19,190
Decision-Theoretic Control of Problem Solving: Principles and Architecture
cs.AI
This paper presents an approach to the design of autonomous, real-time systems operating in uncertain environments. We address issues of problem solving and reflective control of reasoning under uncertainty in terms of two fundamental elements: l) a set of decision-theoretic models for selecting among alternative probl...
computer science
19,191
Induction and Uncertainty Management Techniques Applied to Veterinary Medical Diagnosis
cs.AI
This paper discusses a project undertaken between the Departments of Computing Science, Statistics, and the College of Veterinary Medicine to design a medical diagnostic system. On-line medical data has been collected in the hospital database system for several years. A number of induction methods are being used to ext...
computer science
19,192
KNET: Integrating Hypermedia and Bayesian Modeling
cs.AI
KNET is a general-purpose shell for constructing expert systems based on belief networks and decision networks. Such networks serve as graphical representations for decision models, in which the knowledge engineer must define clearly the alternatives, states, preferences, and relationships that constitute a decision ba...
computer science
19,193
A Method for Using Belief Networks as Influence Diagrams
cs.AI
This paper demonstrates a method for using belief-network algorithms to solve influence diagram problems. In particular, both exact and approximation belief-network algorithms may be applied to solve influence-diagram problems. More generally, knowing the relationship between belief-network and influence-diagram proble...
computer science
19,194
Process, Structure, and Modularity in Reasoning with Uncertainty
cs.AI
Computational mechanisms for uncertainty management must support interactive and incremental problem formulation, inference, hypothesis testing, and decision making. However, most current uncertainty inference systems concentrate primarily on inference, and provide no support for the larger issues. We present a computa...
computer science
19,195
Probabilistic Causal Reasoning
cs.AI
Predicting the future is an important component of decision making. In most situations, however, there is not enough information to make accurate predictions. In this paper, we develop a theory of causal reasoning for predictive inference under uncertainty. We emphasize a common type of prediction that involves reasoni...
computer science
19,196
Modeling uncertain and vague knowledge in possibility and evidence theories
cs.AI
This paper advocates the usefulness of new theories of uncertainty for the purpose of modeling some facets of uncertain knowledge, especially vagueness, in AI. It can be viewed as a partial reply to Cheeseman's (among others) defense of probability.
computer science
19,197
A Temporal Logic for Uncertain Events and An Outline of A Possible Implementation in An Extension of PROLOG
cs.AI
There is uncertainty associated with the occurrence of many events in real life. In this paper we develop a temporal logic to deal with such uncertain events and outline a possible implementation in an extension of PROLOG. Events are represented as fuzzy sets with the membership function giving the possibility of occur...
computer science
19,198
Uncertainty Management for Fuzzy Decision Support Systems
cs.AI
A new approach for uncertainty management for fuzzy, rule based decision support systems is proposed: The domain expert's knowledge is expressed by a set of rules that frequently refer to vague and uncertain propositions. The certainty of propositions is represented using intervals [a, b] expressing that the propositio...
computer science
19,199
Probability as a Modal Operator
cs.AI
This paper argues for a modal view of probability. The syntax and semantics of one particularly strong probability logic are discussed and some examples of the use of the logic are provided. We show that it is both natural and useful to think of probability as a modal operator. Contrary to popular belief in AI, a proba...
computer science
19,200
Truth Maintenance Under Uncertainty
cs.AI
This paper addresses the problem of resolving errors under uncertainty in a rule-based system. A new approach has been developed that reformulates this problem as a neural-network learning problem. The strength and the fundamental limitations of this approach are explored and discussed. The main result is that neural h...
computer science
19,201
Bayesian Assessment of a Connectionist Model for Fault Detection
cs.AI
A previous paper [2] showed how to generate a linear discriminant network (LDN) that computes likely faults for a noisy fault detection problem by using a modification of the perceptron learning algorithm called the pocket algorithm. Here we compare the performance of this connectionist model with performance of the op...
computer science