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1302.3603
Ross D. Shachter
Ross D. Shachter, Marvin Mandelbaum
A Measure of Decision Flexibility
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-485-491
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a decision-analytical approach to comparing the flexibility of decision situations from the perspective of a decision-maker who exhibits constant risk-aversion over a monetary value model. Our approach is simple yet seems to be consistent with a variety of flexibility concepts, including robust and adaptive alternatives. We try to compensate within the model for uncertainty that was not anticipated or not modeled. This approach not only allows one to compare the flexibility of plans, but also guides the search for new, more flexible alternatives.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:16:35 GMT" } ]
1,361,145,600,000
[ [ "Shachter", "Ross D.", "" ], [ "Mandelbaum", "Marvin", "" ] ]
1302.3604
Prakash P. Shenoy
Prakash P. Shenoy
Binary Join Trees
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-492-499
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The main goal of this paper is to describe a data structure called binary join trees that are useful in computing multiple marginals efficiently using the Shenoy-Shafer architecture. We define binary join trees, describe their utility, and sketch a procedure for constructing them.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:16:41 GMT" } ]
1,361,145,600,000
[ [ "Shenoy", "Prakash P.", "" ] ]
1302.3605
Sampath Srinivas
Sampath Srinivas, Pandurang Nayak
Efficient Enumeration of Instantiations in Bayesian Networks
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-500-508
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Over the past several years Bayesian networks have been applied to a wide variety of problems. A central problem in applying Bayesian networks is that of finding one or more of the most probable instantiations of a network. In this paper we develop an efficient algorithm that incrementally enumerates the instantiations of a Bayesian network in decreasing order of probability. Such enumeration algorithms are applicable in a variety of applications ranging from medical expert systems to model-based diagnosis. Fundamentally, our algorithm is simply performing a lazy enumeration of the sorted list of all instantiations of the network. This insight leads to a very concise algorithm statement which is both easily understood and implemented. We show that for singly connected networks, our algorithm generates the next instantiation in time polynomial in the size of the network. The algorithm extends to arbitrary Bayesian networks using standard conditioning techniques. We empirically evaluate the enumeration algorithm and demonstrate its practicality.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:16:47 GMT" } ]
1,361,145,600,000
[ [ "Srinivas", "Sampath", "" ], [ "Nayak", "Pandurang", "" ] ]
1302.3606
Milan Studeny
Milan Studeny
On Separation Criterion and Recovery Algorithm for Chain Graphs
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-509-516
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Chain graphs give a natural unifying point of view on Markov and Bayesian networks and enlarge the potential of graphical models for description of conditional independence structures. In the paper a direct graphical separation criterion for chain graphs, called c-separation, which generalizes the d-separation criterion for Bayesian networks is introduced (recalled). It is equivalent to the classic moralization criterion for chain graphs and complete in sense that for every chain graph there exists a probability distribution satisfying exactly conditional independencies derivable from the chain graph by the c-separation criterion. Every class of Markov equivalent chain graphs can be uniquely described by a natural representative, called the largest chain graph. A recovery algorithm, which on basis of the (conditional) dependency model induced by an unknown chain graph finds the corresponding largest chain graph, is presented.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:16:53 GMT" } ]
1,361,145,600,000
[ [ "Studeny", "Milan", "" ] ]
1302.3607
Choh Man Teng
Choh Man Teng
Possible World Partition Sequences: A Unifying Framework for Uncertain Reasoning
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-517-524
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
When we work with information from multiple sources, the formalism each employs to handle uncertainty may not be uniform. In order to be able to combine these knowledge bases of different formats, we need to first establish a common basis for characterizing and evaluating the different formalisms, and provide a semantics for the combined mechanism. A common framework can provide an infrastructure for building an integrated system, and is essential if we are to understand its behavior. We present a unifying framework based on an ordered partition of possible worlds called partition sequences, which corresponds to our intuitive notion of biasing towards certain possible scenarios when we are uncertain of the actual situation. We show that some of the existing formalisms, namely, default logic, autoepistemic logic, probabilistic conditioning and thresholding (generalized conditioning), and possibility theory can be incorporated into this general framework.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:17:00 GMT" } ]
1,361,145,600,000
[ [ "Teng", "Choh Man", "" ] ]
1302.3608
Sylvie Thiebaux
Sylvie Thiebaux, Marie-Odile Cordier, Olivier Jehl, Jean-Paul Krivine
Supply Restoration in Power Distribution Systems - A Case Study in Integrating Model-Based Diagnosis and Repair Planning
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-525-532
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Integrating diagnosis and repair is particularly crucial when gaining sufficient information to discriminate between several candidate diagnoses requires carrying out some repair actions. A typical case is supply restoration in a faulty power distribution system. This problem, which is a major concern for electricity distributors, features partial observability, and stochastic repair actions which are more elaborate than simple replacement of components. This paper analyses the difficulties in applying existing work on integrating model-based diagnosis and repair and on planning in partially observable stochastic domains to this real-world problem, and describes the pragmatic approach we have retained so far.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:17:05 GMT" } ]
1,361,145,600,000
[ [ "Thiebaux", "Sylvie", "" ], [ "Cordier", "Marie-Odile", "" ], [ "Jehl", "Olivier", "" ], [ "Krivine", "Jean-Paul", "" ] ]
1302.3609
Robert L. Welch
Robert L. Welch
Real Time Estimation of Bayesian Networks
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-533-544
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
For real time evaluation of a Bayesian network when there is not sufficient time to obtain an exact solution, a guaranteed response time, approximate solution is required. It is shown that nontraditional methods utilizing estimators based on an archive of trial solutions and genetic search can provide an approximate solution that is considerably superior to the traditional Monte Carlo simulation methods.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:17:11 GMT" } ]
1,361,145,600,000
[ [ "Welch", "Robert L.", "" ] ]
1302.3610
Michael S. K. M. Wong
Michael S. K. M. Wong
Testing Implication of Probabilistic Dependencies
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-545-553
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Axiomatization has been widely used for testing logical implications. This paper suggests a non-axiomatic method, the chase, to test if a new dependency follows from a given set of probabilistic dependencies. Although the chase computation may require exponential time in some cases, this technique is a powerful tool for establishing nontrivial theoretical results. More importantly, this approach provides valuable insight into the intriguing connection between relational databases and probabilistic reasoning systems.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:17:17 GMT" } ]
1,361,145,600,000
[ [ "Wong", "Michael S. K. M.", "" ] ]
1302.3611
Peter R. Wurman
Peter R. Wurman, Michael P. Wellman
Optimal Factory Scheduling using Stochastic Dominance A*
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-554-563
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine a standard factory scheduling problem with stochastic processing and setup times, minimizing the expectation of the weighted number of tardy jobs. Because the costs of operators in the schedule are stochastic and sequence dependent, standard dynamic programming algorithms such as A* may fail to find the optimal schedule. The SDA* (Stochastic Dominance A*) algorithm remedies this difficulty by relaxing the pruning condition. We present an improved state-space search formulation for these problems and discuss the conditions under which stochastic scheduling problems can be solved optimally using SDA*. In empirical testing on randomly generated problems, we found that in 70%, the expected cost of the optimal stochastic solution is lower than that of the solution derived using a deterministic approximation, with comparable search effort.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:17:23 GMT" } ]
1,361,145,600,000
[ [ "Wurman", "Peter R.", "" ], [ "Wellman", "Michael P.", "" ] ]
1302.3612
Yang Xiang
Yang Xiang, Michael S. K. M. Wong, N. Cercone
Critical Remarks on Single Link Search in Learning Belief Networks
Appears in Proceedings of the Twelfth Conference on Uncertainty in Artificial Intelligence (UAI1996)
null
null
UAI-P-1996-PG-564-571
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In learning belief networks, the single link lookahead search is widely adopted to reduce the search space. We show that there exists a class of probabilistic domain models which displays a special pattern of dependency. We analyze the behavior of several learning algorithms using different scoring metrics such as the entropy, conditional independence, minimal description length and Bayesian metrics. We demonstrate that single link lookahead search procedures (employed in these algorithms) cannot learn these models correctly. Thus, when the underlying domain model actually belongs to this class, the use of a single link search procedure will result in learning of an incorrect model. This may lead to inference errors when the model is used. Our analysis suggests that if the prior knowledge about a domain does not rule out the possible existence of these models, a multi-link lookahead search or other heuristics should be used for the learning process.
[ { "version": "v1", "created": "Wed, 13 Feb 2013 14:17:29 GMT" } ]
1,361,145,600,000
[ [ "Xiang", "Yang", "" ], [ "Wong", "Michael S. K. M.", "" ], [ "Cercone", "N.", "" ] ]
1302.4381
Marc Maier
Marc Maier, Katerina Marazopoulou, David Jensen
Reasoning about Independence in Probabilistic Models of Relational Data
61 pages, substantial revisions to formalisms, theory, and related work
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We extend the theory of d-separation to cases in which data instances are not independent and identically distributed. We show that applying the rules of d-separation directly to the structure of probabilistic models of relational data inaccurately infers conditional independence. We introduce relational d-separation, a theory for deriving conditional independence facts from relational models. We provide a new representation, the abstract ground graph, that enables a sound, complete, and computationally efficient method for answering d-separation queries about relational models, and we present empirical results that demonstrate effectiveness.
[ { "version": "v1", "created": "Mon, 18 Feb 2013 18:33:47 GMT" }, { "version": "v2", "created": "Fri, 10 May 2013 21:20:06 GMT" }, { "version": "v3", "created": "Mon, 6 Jan 2014 18:04:39 GMT" } ]
1,389,052,800,000
[ [ "Maier", "Marc", "" ], [ "Marazopoulou", "Katerina", "" ], [ "Jensen", "David", "" ] ]
1302.4928
Fahiem Bacchus
Fahiem Bacchus, Adam J. Grove
Graphical Models for Preference and Utility
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-3-10
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Probabilistic independence can dramatically simplify the task of eliciting, representing, and computing with probabilities in large domains. A key technique in achieving these benefits is the idea of graphical modeling. We survey existing notions of independence for utility functions in a multi-attribute space, and suggest that these can be used to achieve similar advantages. Our new results concern conditional additive independence, which we show always has a perfect representation as separation in an undirected graph (a Markov network). Conditional additive independencies entail a particular functional for the utility function that is analogous to a product decomposition of a probability function, and confers analogous benefits. This functional form has been utilized in the Bayesian network and influence diagram literature, but generally without an explanation in terms of independence. The functional form yields a decomposition of the utility function that can greatly speed up expected utility calculations, particularly when the utility graph has a similar topology to the probabilistic network being used.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:18:51 GMT" } ]
1,361,404,800,000
[ [ "Bacchus", "Fahiem", "" ], [ "Grove", "Adam J.", "" ] ]
1302.4929
Alexander Balke
Alexander Balke, Judea Pearl
Counterfactuals and Policy Analysis in Structural Models
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-11-18
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Evaluation of counterfactual queries (e.g., "If A were true, would C have been true?") is important to fault diagnosis, planning, determination of liability, and policy analysis. We present a method of revaluating counterfactuals when the underlying causal model is represented by structural models - a nonlinear generalization of the simultaneous equations models commonly used in econometrics and social sciences. This new method provides a coherent means for evaluating policies involving the control of variables which, prior to enacting the policy were influenced by other variables in the system.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:18:56 GMT" } ]
1,361,404,800,000
[ [ "Balke", "Alexander", "" ], [ "Pearl", "Judea", "" ] ]
1302.4930
Salem Benferhat
Salem Benferhat, Alessandro Saffiotti, Philippe Smets
Belief Functions and Default Reasoning
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-19-26
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new approach to dealing with default information based on the theory of belief functions. Our semantic structures, inspired by Adams' epsilon-semantics, are epsilon-belief assignments, where values committed to focal elements are either close to 0 or close to 1. We define two systems based on these structures, and relate them to other non-monotonic systems presented in the literature. We show that our second system correctly addresses the well-known problems of specificity, irrelevance, blocking of inheritance, ambiguity, and redundancy.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:02 GMT" } ]
1,361,404,800,000
[ [ "Benferhat", "Salem", "" ], [ "Saffiotti", "Alessandro", "" ], [ "Smets", "Philippe", "" ] ]
1302.4932
John S. Breese
John S. Breese, Russ Blake
Automating Computer Bottleneck Detection with Belief Nets
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-36-45
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe an application of belief networks to the diagnosis of bottlenecks in computer systems. The technique relies on a high-level functional model of the interaction between application workloads, the Windows NT operating system, and system hardware. Given a workload description, the model predicts the values of observable system counters available from the Windows NT performance monitoring tool. Uncertainty in workloads, predictions, and counter values are characterized with Gaussian distributions. During diagnostic inference, we use observed performance monitor values to find the most probable assignment to the workload parameters. In this paper we provide some background on automated bottleneck detection, describe the structure of the system model, and discuss empirical procedures for model calibration and verification. Part of the calibration process includes generating a dataset to estimate a multivariate Gaussian error model. Initial results in diagnosing bottlenecks are presented.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:11 GMT" } ]
1,361,404,800,000
[ [ "Breese", "John S.", "" ], [ "Blake", "Russ", "" ] ]
1302.4933
Wray L. Buntine
Wray L. Buntine
Chain Graphs for Learning
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-46-54
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Chain graphs combine directed and undirected graphs and their underlying mathematics combines properties of the two. This paper gives a simplified definition of chain graphs based on a hierarchical combination of Bayesian (directed) and Markov (undirected) networks. Examples of a chain graph are multivariate feed-forward networks, clustering with conditional interaction between variables, and forms of Bayes classifiers. Chain graphs are then extended using the notation of plates so that samples and data analysis problems can be represented in a graphical model as well. Implications for learning are discussed in the conclusion.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:16 GMT" } ]
1,361,404,800,000
[ [ "Buntine", "Wray L.", "" ] ]
1302.4934
Enrique F. Castillo
Enrique F. Castillo, Remco R. Bouckaert, Jose M. Sarabia, Cristina Solares
Error Estimation in Approximate Bayesian Belief Network Inference
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-55-62
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We can perform inference in Bayesian belief networks by enumerating instantiations with high probability thus approximating the marginals. In this paper, we present a method for determining the fraction of instantiations that has to be considered such that the absolute error in the marginals does not exceed a predefined value. The method is based on extreme value theory. Essentially, the proposed method uses the reversed generalized Pareto distribution to model probabilities of instantiations below a given threshold. Based on this distribution, an estimate of the maximal absolute error if instantiations with probability smaller than u are disregarded can be made.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:22 GMT" } ]
1,361,404,800,000
[ [ "Castillo", "Enrique F.", "" ], [ "Bouckaert", "Remco R.", "" ], [ "Sarabia", "Jose M.", "" ], [ "Solares", "Cristina", "" ] ]
1302.4935
Juan Luis Castro
Juan Luis Castro, Jose Manuel Zurita
Generating the Structure of a Fuzzy Rule under Uncertainty
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-63-67
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The aim of this paper is to present a method for identifying the structure of a rule in a fuzzy model. For this purpose, an ATMS shall be used (Zurita 1994). An algorithm obtaining the identification of the structure will be suggested (Castro 1995). The minimal structure of the rule (with respect to the number of variables that must appear in the rule) will be found by this algorithm. Furthermore, the identification parameters shall be obtained simultaneously. The proposed method shall be applied for classification to an example. The {em Iris Plant Database} shall be learnt for all three kinds of plants.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:27 GMT" } ]
1,361,404,800,000
[ [ "Castro", "Juan Luis", "" ], [ "Zurita", "Jose Manuel", "" ] ]
1302.4936
Didier Cayrac
Didier Cayrac, Didier Dubois, Henri Prade
Practical Model-Based Diagnosis with Qualitative Possibilistic Uncertainty
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-68-76
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An approach to fault isolation that exploits vastly incomplete models is presented. It relies on separate descriptions of each component behavior, together with the links between them, which enables focusing of the reasoning to the relevant part of the system. As normal observations do not need explanation, the behavior of the components is limited to anomaly propagation. Diagnostic solutions are disorders (fault modes or abnormal signatures) that are consistent with the observations, as well as abductive explanations. An ordinal representation of uncertainty based on possibility theory provides a simple exception-tolerant description of the component behaviors. We can for instance distinguish between effects that are more or less certainly present (or absent) and effects that are more or less certainly present (or absent) when a given anomaly is present. A realistic example illustrates the benefits of this approach.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:32 GMT" } ]
1,361,404,800,000
[ [ "Cayrac", "Didier", "" ], [ "Dubois", "Didier", "" ], [ "Prade", "Henri", "" ] ]
1302.4937
Tom Chavez
Tom Chavez, Ross D. Shachter
Decision Flexibility
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-77-86
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The development of new methods and representations for temporal decision-making requires a principled basis for characterizing and measuring the flexibility of decision strategies in the face of uncertainty. Our goal in this paper is to provide a framework - not a theory - for observing how decision policies behave in the face of informational perturbations, to gain clues as to how they might behave in the face of unanticipated, possibly unarticulated uncertainties. To this end, we find it beneficial to distinguish between two types of uncertainty: "Small World" and "Large World" uncertainty. The first type can be resolved by posing an unambiguous question to a "clairvoyant," and is anchored on some well-defined aspect of a decision frame. The second type is more troublesome, yet it is often of greater interest when we address the issue of flexibility; this type of uncertainty can be resolved only by consulting a "psychic." We next observe that one approach to flexibility used in the economics literature is already implicitly accounted for in the Maximum Expected Utility (MEU) principle from decision theory. Though simple, the observation establishes the context for a more illuminating notion of flexibility, what we term flexibility with respect to information revelation. We show how to perform flexibility analysis of a static (i.e., single period) decision problem using a simple example, and we observe that the most flexible alternative thus identified is not necessarily the MEU alternative. We extend our analysis for a dynamic (i.e., multi-period) model, and we demonstrate how to calculate the value of flexibility for decision strategies that allow downstream revision of an upstream commitment decision.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:37 GMT" } ]
1,361,404,800,000
[ [ "Chavez", "Tom", "" ], [ "Shachter", "Ross D.", "" ] ]
1302.4938
David Maxwell Chickering
David Maxwell Chickering
A Transformational Characterization of Equivalent Bayesian Network Structures
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-87-98
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a simple characterization of equivalent Bayesian network structures based on local transformations. The significance of the characterization is twofold. First, we are able to easily prove several new invariant properties of theoretical interest for equivalent structures. Second, we use the characterization to derive an efficient algorithm that identifies all of the compelled edges in a structure. Compelled edge identification is of particular importance for learning Bayesian network structures from data because these edges indicate causal relationships when certain assumptions hold.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:42 GMT" } ]
1,361,404,800,000
[ [ "Chickering", "David Maxwell", "" ] ]
1302.4939
Adnan Darwiche
Adnan Darwiche
Conditioning Methods for Exact and Approximate Inference in Causal Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-99-107
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present two algorithms for exact and approximate inference in causal networks. The first algorithm, dynamic conditioning, is a refinement of cutset conditioning that has linear complexity on some networks for which cutset conditioning is exponential. The second algorithm, B-conditioning, is an algorithm for approximate inference that allows one to trade-off the quality of approximations with the computation time. We also present some experimental results illustrating the properties of the proposed algorithms.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:47 GMT" } ]
1,361,404,800,000
[ [ "Darwiche", "Adnan", "" ] ]
1302.4940
Luis M. de Campos
Luis M. de Campos, Serafin Moral
Independence Concepts for Convex Sets of Probabilities
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-108-115
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we study different concepts of independence for convex sets of probabilities. There will be two basic ideas for independence. The first is irrelevance. Two variables are independent when a change on the knowledge about one variable does not affect the other. The second one is factorization. Two variables are independent when the joint convex set of probabilities can be decomposed on the product of marginal convex sets. In the case of the Theory of Probability, these two starting points give rise to the same definition. In the case of convex sets of probabilities, the resulting concepts will be strongly related, but they will not be equivalent. As application of the concept of independence, we shall consider the problem of building a global convex set from marginal convex sets of probabilities.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:52 GMT" } ]
1,361,404,800,000
[ [ "de Campos", "Luis M.", "" ], [ "Moral", "Serafin", "" ] ]
1302.4941
Denise L. Draper
Denise L. Draper
Clustering Without (Thinking About) Triangulation
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-125-133
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The undirected technique for evaluating belief networks [Jensen, et.al., 1990, Lauritzen and Spiegelhalter, 1988] requires clustering the nodes in the network into a junction tree. In the traditional view, the junction tree is constructed from the cliques of the moralized and triangulated belief network: triangulation is taken to be the primitive concept, the goal towards which any clustering algorithm (e.g. node elimination) is directed. In this paper, we present an alternative conception of clustering, in which clusters and the junction tree property play the role of primitives: given a graph (not a tree) of clusters which obey (a modified version of) the junction tree property, we transform this graph until we have obtained a tree. There are several advantages to this approach: it is much clearer and easier to understand, which is important for humans who are constructing belief networks; it admits a wider range of heuristics which may enable more efficient or superior clustering algorithms; and it serves as the natural basis for an incremental clustering scheme, which we describe.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:19:57 GMT" } ]
1,361,404,800,000
[ [ "Draper", "Denise L.", "" ] ]
1302.4942
Eric Driver
Eric Driver, Darryl Morrell
Implementation of Continuous Bayesian Networks Using Sums of Weighted Gaussians
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-134-140
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian networks provide a method of representing conditional independence between random variables and computing the probability distributions associated with these random variables. In this paper, we extend Bayesian network structures to compute probability density functions for continuous random variables. We make this extension by approximating prior and conditional densities using sums of weighted Gaussian distributions and then finding the propagation rules for updating the densities in terms of these weights. We present a simple example that illustrates the Bayesian network for continuous variables; this example shows the effect of the network structure and approximation errors on the computation of densities for variables in the network.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:02 GMT" } ]
1,361,404,800,000
[ [ "Driver", "Eric", "" ], [ "Morrell", "Darryl", "" ] ]
1302.4943
Marek J. Druzdzel
Marek J. Druzdzel, Linda C. van der Gaag
Elicitation of Probabilities for Belief Networks: Combining Qualitative and Quantitative Information
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-141-148
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Although the usefulness of belief networks for reasoning under uncertainty is widely accepted, obtaining numerical probabilities that they require is still perceived a major obstacle. Often not enough statistical data is available to allow for reliable probability estimation. Available information may not be directly amenable for encoding in the network. Finally, domain experts may be reluctant to provide numerical probabilities. In this paper, we propose a method for elicitation of probabilities from a domain expert that is non-invasive and accommodates whatever probabilistic information the expert is willing to state. We express all available information, whether qualitative or quantitative in nature, in a canonical form consisting of (in) equalities expressing constraints on the hyperspace of possible joint probability distributions. We then use this canonical form to derive second-order probability distributions over the desired probabilities.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:07 GMT" } ]
1,361,404,800,000
[ [ "Druzdzel", "Marek J.", "" ], [ "van der Gaag", "Linda C.", "" ] ]
1302.4944
Didier Dubois
Didier Dubois, Henri Prade
Numerical Representations of Acceptance
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-149-156
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Accepting a proposition means that our confidence in this proposition is strictly greater than the confidence in its negation. This paper investigates the subclass of uncertainty measures, expressing confidence, that capture the idea of acceptance, what we call acceptance functions. Due to the monotonicity property of confidence measures, the acceptance of a proposition entails the acceptance of any of its logical consequences. In agreement with the idea that a belief set (in the sense of Gardenfors) must be closed under logical consequence, it is also required that the separate acceptance o two propositions entail the acceptance of their conjunction. Necessity (and possibility) measures agree with this view of acceptance while probability and belief functions generally do not. General properties of acceptance functions are estabilished. The motivation behind this work is the investigation of a setting for belief revision more general than the one proposed by Alchourron, Gardenfors and Makinson, in connection with the notion of conditioning.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:13 GMT" } ]
1,361,404,800,000
[ [ "Dubois", "Didier", "" ], [ "Prade", "Henri", "" ] ]
1302.4945
Kazuo J. Ezawa
Kazuo J. Ezawa, Til Schuermann
Fraud/Uncollectible Debt Detection Using a Bayesian Network Based Learning System: A Rare Binary Outcome with Mixed Data Structures
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-157-166
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The fraud/uncollectible debt problem in the telecommunications industry presents two technical challenges: the detection and the treatment of the account given the detection. In this paper, we focus on the first problem of detection using Bayesian network models, and we briefly discuss the application of a normative expert system for the treatment at the end. We apply Bayesian network models to the problem of fraud/uncollectible debt detection for telecommunication services. In addition to being quite successful at predicting rare event outcomes, it is able to handle a mixture of categorical and continuous data. We present a performance comparison using linear and non-linear discriminant analysis, classification and regression trees, and Bayesian network models
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:19 GMT" } ]
1,361,404,800,000
[ [ "Ezawa", "Kazuo J.", "" ], [ "Schuermann", "Til", "" ] ]
1302.4946
Helene Fargier
Helene Fargier, Jerome Lang, Roger Martin-Clouaire, Thomas Schiex
A Constraint Satisfaction Approach to Decision under Uncertainty
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-167-174
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Constraint Satisfaction Problem (CSP) framework offers a simple and sound basis for representing and solving simple decision problems, without uncertainty. This paper is devoted to an extension of the CSP framework enabling us to deal with some decisions problems under uncertainty. This extension relies on a differentiation between the agent-controllable decision variables and the uncontrollable parameters whose values depend on the occurrence of uncertain events. The uncertainty on the values of the parameters is assumed to be given under the form of a probability distribution. Two algorithms are given, for computing respectively decisions solving the problem with a maximal probability, and conditional decisions mapping the largest possible amount of possible cases to actual decisions.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:24 GMT" } ]
1,361,404,800,000
[ [ "Fargier", "Helene", "" ], [ "Lang", "Jerome", "" ], [ "Martin-Clouaire", "Roger", "" ], [ "Schiex", "Thomas", "" ] ]
1302.4947
Nir Friedman
Nir Friedman, Joseph Y. Halpern
Plausibility Measures: A User's Guide
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-175-184
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine a new approach to modeling uncertainty based on plausibility measures, where a plausibility measure just associates with an event its plausibility, an element is some partially ordered set. This approach is easily seen to generalize other approaches to modeling uncertainty, such as probability measures, belief functions, and possibility measures. The lack of structure in a plausibility measure makes it easy for us to add structure on an "as needed" basis, letting us examine what is required to ensure that a plausibility measure has certain properties of interest. This gives us insight into the essential features of the properties in question, while allowing us to prove general results that apply to many approaches to reasoning about uncertainty. Plausibility measures have already proved useful in analyzing default reasoning. In this paper, we examine their "algebraic properties," analogues to the use of + and * in probability theory. An understanding of such properties will be essential if plausibility measures are to be used in practice as a representation tool.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:29 GMT" } ]
1,361,404,800,000
[ [ "Friedman", "Nir", "" ], [ "Halpern", "Joseph Y.", "" ] ]
1302.4948
David Galles
David Galles, Judea Pearl
Testing Identifiability of Causal Effects
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-185-195
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper concerns the probabilistic evaluation of the effects of actions in the presence of unmeasured variables. We show that the identification of causal effect between a singleton variable X and a set of variables Y can be accomplished systematically, in time polynomial in the number of variables in the graph. When the causal effect is identifiable, a closed-form expression can be obtained for the probability that the action will achieve a specified goal, or a set of goals.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:35 GMT" } ]
1,361,404,800,000
[ [ "Galles", "David", "" ], [ "Pearl", "Judea", "" ] ]
1302.4950
Moises Goldszmidt
Moises Goldszmidt
Fast Belief Update Using Order-of-Magnitude Probabilities
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-208-216
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an algorithm, called Predict, for updating beliefs in causal networks quantified with order-of-magnitude probabilities. The algorithm takes advantage of both the structure and the quantification of the network and presents a polynomial asymptotic complexity. Predict exhibits a conservative behavior in that it is always sound but not always complete. We provide sufficient conditions for completeness and present algorithms for testing these conditions and for computing a complete set of plausible values. We propose Predict as an efficient method to estimate probabilistic values and illustrate its use in conjunction with two known algorithms for probabilistic inference. Finally, we describe an application of Predict to plan evaluation, present experimental results, and discuss issues regarding its use with conditional logics of belief, and in the characterization of irrelevance.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:47 GMT" } ]
1,361,404,800,000
[ [ "Goldszmidt", "Moises", "" ] ]
1302.4951
Benjamin N. Grosof
Benjamin N. Grosof
Transforming Prioritized Defaults and Specificity into Parallel Defaults
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-217-228
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show how to transform any set of prioritized propositional defaults into an equivalent set of parallel (i.e., unprioritized) defaults, in circumscription. We give an algorithm to implement the transform. We show how to use the transform algorithm as a generator of a whole family of inferencing algorithms for circumscription. The method is to employ the transform algorithm as a front end to any inferencing algorithm, e.g., one of the previously available, that handles the parallel (empty) case of prioritization. Our algorithms provide not just coverage of a new expressive class, but also alternatives to previous algorithms for implementing the previously covered class (?layered?) of prioritization. In particular, we give a new query-answering algorithm for prioritized cirumscription which is sound and complete for the full expressive class of unrestricted finite prioritization partial orders, for propositional defaults (or minimized predicates). By contrast, previous algorithms required that the prioritization partial order be layered, i.e., structured similar to the system of rank in the military. Our algorithm enables, for the first time, the implementation of the most useful class of prioritization: non-layered prioritization partial orders. Default inheritance, for example, typically requires non-layered prioritization to represent specificity adequately. Our algorithm enables not only the implementation of default inheritance (and specificity) within prioritized circumscription, but also the extension and combination of default inheritance with other kinds of prioritized default reasoning, e.g.: with stratified logic programs with negation-as-failure. Such logic programs are previously known to be representable equivalently as layered-priority predicate circumscriptions. Worst-case, the transform increases the number of defaults exponentially. We discuss how inferencing is practically implementable nevertheless in two kinds of situations: general expressiveness but small numbers of defaults, or expressive special cases with larger numbers of defaults. One such expressive special case is non-?top-heaviness? of the prioritization partial order. In addition to its direct implementation, the transform can also be exploited analytically to generate special case algorithms, e.g., a tractable transform for a class within default inheritance (detailed in another, forthcoming paper). We discuss other aspects of the significance of the fundamental result. One can view the transform as reducing n degrees of partially ordered belief confidence to just 2 degrees of confidence: for-sure and (unprioritized) default. Ordinary, parallel default reasoning, e.g., in parallel circumscription or Poole's Theorist, can be viewed in these terms as reducing 2 degrees of confidence to just 1 degree of confidence: that of the non-monotonic theory's conclusions. The expressive reduction's computational complexity suggests that prioritization is valuable for its expressive conciseness, just as defaults are for theirs. For Reiter's Default Logic and Poole's Theorist, the transform implies how to extend those formalisms so as to equip them with a concept of prioritization that is exactly equivalent to that in circumscription. This provides an interesting alternative to Brewka's approach to equipping them with prioritization-type precedence.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:52 GMT" } ]
1,361,404,800,000
[ [ "Grosof", "Benjamin N.", "" ] ]
1302.4952
Peter Haddawy
Peter Haddawy, AnHai Doan, Richard Goodwin
Efficient Decision-Theoretic Planning: Techniques and Empirical Analysis
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-229-236
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper discusses techniques for performing efficient decision-theoretic planning. We give an overview of the DRIPS decision-theoretic refinement planning system, which uses abstraction to efficiently identify optimal plans. We present techniques for automatically generating search control information, which can significantly improve the planner's performance. We evaluate the efficiency of DRIPS both with and without the search control rules on a complex medical planning problem and compare its performance to that of a branch-and-bound decision tree algorithm.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:20:57 GMT" } ]
1,361,404,800,000
[ [ "Haddawy", "Peter", "" ], [ "Doan", "AnHai", "" ], [ "Goodwin", "Richard", "" ] ]
1302.4953
Petr Hajek
Petr Hajek, Lluis Godo, Francesc Esteva
Fuzzy Logic and Probability
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-237-244
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we deal with a new approach to probabilistic reasoning in a logical framework. Nearly almost all logics of probability that have been proposed in the literature are based on classical two-valued logic. After making clear the differences between fuzzy logic and probability theory, here we propose a {em fuzzy} logic of probability for which completeness results (in a probabilistic sense) are provided. The main idea behind this approach is that probability values of crisp propositions can be understood as truth-values of some suitable fuzzy propositions associated to the crisp ones. Moreover, suggestions and examples of how to extend the formalism to cope with conditional probabilities and with other uncertainty formalisms are also provided.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:03 GMT" } ]
1,361,404,800,000
[ [ "Hajek", "Petr", "" ], [ "Godo", "Lluis", "" ], [ "Esteva", "Francesc", "" ] ]
1302.4954
Steve Hanks
Steve Hanks, David Madigan, Jonathan Gavrin
Probabilistic Temporal Reasoning with Endogenous Change
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-245-254
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents a probabilistic model for reasoning about the state of a system as it changes over time, both due to exogenous and endogenous influences. Our target domain is a class of medical prediction problems that are neither so urgent as to preclude careful diagnosis nor progress so slowly as to allow arbitrary testing and treatment options. In these domains there is typically enough time to gather information about the patient's state and consider alternative diagnoses and treatments, but the temporal interaction between the timing of tests, treatments, and the course of the disease must also be considered. Our approach is to elicit a qualitative structural model of the patient from a human expert---the model identifies important attributes, the way in which exogenous changes affect attribute values, and the way in which the patient's condition changes endogenously. We then elicit probabilistic information to capture the expert's uncertainty about the effects of tests and treatments and the nature and timing of endogenous state changes. This paper describes the model in the context of a problem in treating vehicle accident trauma, and suggests a method for solving the model based on the technique of sequential imputation. A complementary goal of this work is to understand and synthesize a disparate collection of research efforts all using the name ?probabilistic temporal reasoning.? This paper analyzes related work and points out essential differences between our proposed model and other approaches in the literature.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:08 GMT" } ]
1,361,404,800,000
[ [ "Hanks", "Steve", "" ], [ "Madigan", "David", "" ], [ "Gavrin", "Jonathan", "" ] ]
1302.4955
David Harmanec
David Harmanec
Toward a Characterization of Uncertainty Measure for the Dempster-Shafer Theory
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-255-261
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This is a working paper summarizing results of an ongoing research project whose aim is to uniquely characterize the uncertainty measure for the Dempster-Shafer Theory. A set of intuitive axiomatic requirements is presented, some of their implications are shown, and the proof is given of the minimality of recently proposed measure AU among all measures satisfying the proposed requirements.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:13 GMT" } ]
1,361,404,800,000
[ [ "Harmanec", "David", "" ] ]
1302.4956
David Heckerman
David Heckerman, Ross D. Shachter
A Definition and Graphical Representation for Causality
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-262-273
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a precise definition of cause and effect in terms of a fundamental notion called unresponsiveness. Our definition is based on Savage's (1954) formulation of decision theory and departs from the traditional view of causation in that our causal assertions are made relative to a set of decisions. An important consequence of this departure is that we can reason about cause locally, not requiring a causal explanation for every dependency. Such local reasoning can be beneficial because it may not be necessary to determine whether a particular dependency is causal to make a decision. Also in this paper, we examine the graphical encoding of causal relationships. We show that influence diagrams in canonical form are an accurate and efficient representation of causal relationships. In addition, we establish a correspondence between canonical form and Pearl's causal theory.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:18 GMT" }, { "version": "v2", "created": "Sat, 16 May 2015 23:43:57 GMT" } ]
1,431,993,600,000
[ [ "Heckerman", "David", "" ], [ "Shachter", "Ross D.", "" ] ]
1302.4957
David Heckerman
David Heckerman, Dan Geiger
Learning Bayesian Networks: A Unification for Discrete and Gaussian Domains
This version has improved pointers to the literature
null
null
UAI-P-1995-PG-274-284
cs.AI
http://creativecommons.org/licenses/by/4.0/
We examine Bayesian methods for learning Bayesian networks from a combination of prior knowledge and statistical data. In particular, we unify the approaches we presented at last year's conference for discrete and Gaussian domains. We derive a general Bayesian scoring metric, appropriate for both domains. We then use this metric in combination with well-known statistical facts about the Dirichlet and normal--Wishart distributions to derive our metrics for discrete and Gaussian domains.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:23 GMT" }, { "version": "v2", "created": "Thu, 13 May 2021 13:25:36 GMT" }, { "version": "v3", "created": "Tue, 29 Jun 2021 19:41:53 GMT" } ]
1,625,097,600,000
[ [ "Heckerman", "David", "" ], [ "Geiger", "Dan", "" ] ]
1302.4958
David Heckerman
David Heckerman
A Bayesian Approach to Learning Causal Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-285-295
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Whereas acausal Bayesian networks represent probabilistic independence, causal Bayesian networks represent causal relationships. In this paper, we examine Bayesian methods for learning both types of networks. Bayesian methods for learning acausal networks are fairly well developed. These methods often employ assumptions to facilitate the construction of priors, including the assumptions of parameter independence, parameter modularity, and likelihood equivalence. We show that although these assumptions also can be appropriate for learning causal networks, we need additional assumptions in order to learn causal networks. We introduce two sufficient assumptions, called {em mechanism independence} and {em component independence}. We show that these new assumptions, when combined with parameter independence, parameter modularity, and likelihood equivalence, allow us to apply methods for learning acausal networks to learn causal networks.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:29 GMT" }, { "version": "v2", "created": "Sat, 16 May 2015 23:38:36 GMT" } ]
1,431,993,600,000
[ [ "Heckerman", "David", "" ] ]
1302.4959
Eric J. Horvitz
Eric J. Horvitz, Matthew Barry
Display of Information for Time-Critical Decision Making
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-296-305
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe methods for managing the complexity of information displayed to people responsible for making high-stakes, time-critical decisions. The techniques provide tools for real-time control of the configuration and quantity of information displayed to a user, and a methodology for designing flexible human-computer interfaces for monitoring applications. After defining a prototypical set of display decision problems, we introduce the expected value of revealed information (EVRI) and the related measure of expected value of displayed information (EVDI). We describe how these measures can be used to enhance computer displays used for monitoring complex systems. We motivate the presentation by discussing our efforts to employ decision-theoretic control of displays for a time-critical monitoring application at the NASA Mission Control Center in Houston.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:34 GMT" } ]
1,361,404,800,000
[ [ "Horvitz", "Eric J.", "" ], [ "Barry", "Matthew", "" ] ]
1302.4960
Eric J. Horvitz
Eric J. Horvitz, Adrian Klein
Reasoning, Metareasoning, and Mathematical Truth: Studies of Theorem Proving under Limited Resources
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-306-314
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In earlier work, we introduced flexible inference and decision-theoretic metareasoning to address the intractability of normative inference. Here, rather than pursuing the task of computing beliefs and actions with decision models composed of distinctions about uncertain events, we examine methods for inferring beliefs about mathematical truth before an automated theorem prover completes a proof. We employ a Bayesian analysis to update belief in truth, given theorem-proving progress, and show how decision-theoretic methods can be used to determine the value of continuing to deliberate versus taking immediate action in time-critical situations.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:39 GMT" } ]
1,361,404,800,000
[ [ "Horvitz", "Eric J.", "" ], [ "Klein", "Adrian", "" ] ]
1302.4961
Mark Hulme
Mark Hulme
Improved Sampling for Diagnostic Reasoning in Bayesian Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-315-322
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian networks offer great potential for use in automating large scale diagnostic reasoning tasks. Gibbs sampling is the main technique used to perform diagnostic reasoning in large richly interconnected Bayesian networks. Unfortunately Gibbs sampling can take an excessive time to generate a representative sample. In this paper we describe and test a number of heuristic strategies for improving sampling in noisy-or Bayesian networks. The strategies include Monte Carlo Markov chain sampling techniques other than Gibbs sampling. Emphasis is put on strategies that can be implemented in distributed systems.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:44 GMT" } ]
1,361,404,800,000
[ [ "Hulme", "Mark", "" ] ]
1302.4962
Finn Verner Jensen
Finn Verner Jensen
Cautious Propagation in Bayesian Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-323-328
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Consider the situation where some evidence e has been entered to a Bayesian network. When performing conflict analysis, sensitivity analysis, or when answering questions like "What if the finding on X had been y instead of x?" you need probabilities P (e'| h), where e' is a subset of e, and h is a configuration of a (possibly empty) set of variables. Cautious propagation is a modification of HUGIN propagation into a Shafer-Shenoy-like architecture. It is less efficient than HUGIN propagation; however, it provides easy access to P (e'| h) for a great deal of relevant subsets e'.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:50 GMT" } ]
1,361,404,800,000
[ [ "Jensen", "Finn Verner", "" ] ]
1302.4963
Ali Jenzarli
Ali Jenzarli
Information/Relevance Influence Diagrams
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-329-337
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we extend the influence diagram (ID) representation for decisions under uncertainty. In the standard ID, arrows into a decision node are only informational; they do not represent constraints on what the decision maker can do. We can represent such constraints only indirectly, using arrows to the children of the decision and sometimes adding more variables to the influence diagram, thus making the ID more complicated. Users of influence diagrams often want to represent constraints by arrows into decision nodes. We represent constraints on decisions by allowing relevance arrows into decision nodes. We call the resulting representation information/relevance influence diagrams (IRIDs). Information/relevance influence diagrams allow for direct representation and specification of constrained decisions. We use a combination of stochastic dynamic programming and Gibbs sampling to solve IRIDs. This method is especially useful when exact methods for solving IDs fail.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:21:55 GMT" } ]
1,361,404,800,000
[ [ "Jenzarli", "Ali", "" ] ]
1302.4965
Keiji Kanazawa
Keiji Kanazawa, Daphne Koller, Stuart Russell
Stochastic Simulation Algorithms for Dynamic Probabilistic Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-346-351
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Stochastic simulation algorithms such as likelihood weighting often give fast, accurate approximations to posterior probabilities in probabilistic networks, and are the methods of choice for very large networks. Unfortunately, the special characteristics of dynamic probabilistic networks (DPNs), which are used to represent stochastic temporal processes, mean that standard simulation algorithms perform very poorly. In essence, the simulation trials diverge further and further from reality as the process is observed over time. In this paper, we present simulation algorithms that use the evidence observed at each time step to push the set of trials back towards reality. The first algorithm, "evidence reversal" (ER) restructures each time slice of the DPN so that the evidence nodes for the slice become ancestors of the state variables. The second algorithm, called "survival of the fittest" sampling (SOF), "repopulates" the set of trials at each time step using a stochastic reproduction rate weighted by the likelihood of the evidence according to each trial. We compare the performance of each algorithm with likelihood weighting on the original network, and also investigate the benefits of combining the ER and SOF methods. The ER/SOF combination appears to maintain bounded error independent of the number of time steps in the simulation.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:06 GMT" } ]
1,480,118,400,000
[ [ "Kanazawa", "Keiji", "" ], [ "Koller", "Daphne", "" ], [ "Russell", "Stuart", "" ] ]
1302.4966
Grigoris I. Karakoulas
Grigoris I. Karakoulas
Probabilistic Exploration in Planning while Learning
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-352-361
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Sequential decision tasks with incomplete information are characterized by the exploration problem; namely the trade-off between further exploration for learning more about the environment and immediate exploitation of the accrued information for decision-making. Within artificial intelligence, there has been an increasing interest in studying planning-while-learning algorithms for these decision tasks. In this paper we focus on the exploration problem in reinforcement learning and Q-learning in particular. The existing exploration strategies for Q-learning are of a heuristic nature and they exhibit limited scaleability in tasks with large (or infinite) state and action spaces. Efficient experimentation is needed for resolving uncertainties when possible plans are compared (i.e. exploration). The experimentation should be sufficient for selecting with statistical significance a locally optimal plan (i.e. exploitation). For this purpose, we develop a probabilistic hill-climbing algorithm that uses a statistical selection procedure to decide how much exploration is needed for selecting a plan which is, with arbitrarily high probability, arbitrarily close to a locally optimal one. Due to its generality the algorithm can be employed for the exploration strategy of robust Q-learning. An experiment on a relatively complex control task shows that the proposed exploration strategy performs better than a typical exploration strategy.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:12 GMT" } ]
1,361,404,800,000
[ [ "Karakoulas", "Grigoris I.", "" ] ]
1302.4967
Young-Gyun Kim
Young-Gyun Kim, Marco Valtorta
On the Detection of Conflicts in Diagnostic Bayesian Networks Using Abstraction
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-362-367
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important issue in the use of expert systems is the so-called brittleness problem. Expert systems model only a limited part of the world. While the explicit management of uncertainty in expert systems itigates the brittleness problem, it is still possible for a system to be used, unwittingly, in ways that the system is not prepared to address. Such a situation may be detected by the method of straw models, first presented by Jensen et al. [1990] and later generalized and justified by Laskey [1991]. We describe an algorithm, which we have implemented, that takes as input an annotated diagnostic Bayesian network (the base model) and constructs, without assistance, a bipartite network to be used as a straw model. We show that in some cases this straw model is better that the independent straw model of Jensen et al., the only other straw model for which a construction algorithm has been designed and implemented.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:17 GMT" } ]
1,361,404,800,000
[ [ "Kim", "Young-Gyun", "" ], [ "Valtorta", "Marco", "" ] ]
1302.4968
Uffe Kj{\ae}rulff
Uffe Kj{\ae}rulff
HUGS: Combining Exact Inference and Gibbs Sampling in Junction Trees
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-368-375
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dawid, Kjaerulff and Lauritzen (1994) provided a preliminary description of a hybrid between Monte-Carlo sampling methods and exact local computations in junction trees. Utilizing the strengths of both methods, such hybrid inference methods has the potential of expanding the class of problems which can be solved under bounded resources as well as solving problems which otherwise resist exact solutions. The paper provides a detailed description of a particular instance of such a hybrid scheme; namely, combination of exact inference and Gibbs sampling in discrete Bayesian networks. We argue that this combination calls for an extension of the usual message passing scheme of ordinary junction trees.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:22 GMT" } ]
1,376,265,600,000
[ [ "Kjærulff", "Uffe", "" ] ]
1302.4969
Alexander V. Kozlov
Alexander V. Kozlov, Jaswinder Pal Singh
Sensitivities: An Alternative to Conditional Probabilities for Bayesian Belief Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-376-385
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show an alternative way of representing a Bayesian belief network by sensitivities and probability distributions. This representation is equivalent to the traditional representation by conditional probabilities, but makes dependencies between nodes apparent and intuitively easy to understand. We also propose a QR matrix representation for the sensitivities and/or conditional probabilities which is more efficient, in both memory requirements and computational speed, than the traditional representation for computer-based implementations of probabilistic inference. We use sensitivities to show that for a certain class of binary networks, the computation time for approximate probabilistic inference with any positive upper bound on the error of the result is independent of the size of the network. Finally, as an alternative to traditional algorithms that use conditional probabilities, we describe an exact algorithm for probabilistic inference that uses the QR-representation for sensitivities and updates probability distributions of nodes in a network according to messages from the neighbors.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:26 GMT" } ]
1,361,404,800,000
[ [ "Kozlov", "Alexander V.", "" ], [ "Singh", "Jaswinder Pal", "" ] ]
1302.4970
Paul J. Krause
Paul J. Krause, John Fox, Philip Judson
Is There a Role for Qualitative Risk Assessment?
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-386-393
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Classically, risk is characterized by a point value probability indicating the likelihood of occurrence of an adverse effect. However, there are domains where the attainability of objective numerical risk characterizations is increasingly being questioned. This paper reviews the arguments in favour of extending classical techniques of risk assessment to incorporate meaningful qualitative and weak quantitative risk characterizations. A technique in which linguistic uncertainty terms are defined in terms of patterns of argument is then proposed. The technique is demonstrated using a prototype computer-based system for predicting the carcinogenic risk due to novel chemical compounds.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:31 GMT" } ]
1,361,404,800,000
[ [ "Krause", "Paul J.", "" ], [ "Fox", "John", "" ], [ "Judson", "Philip", "" ] ]
1302.4971
Michael L. Littman
Michael L. Littman, Thomas L. Dean, Leslie Pack Kaelbling
On the Complexity of Solving Markov Decision Problems
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-394-402
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Markov decision problems (MDPs) provide the foundations for a number of problems of interest to AI researchers studying automated planning and reinforcement learning. In this paper, we summarize results regarding the complexity of solving MDPs and the running time of MDP solution algorithms. We argue that, although MDPs can be solved efficiently in theory, more study is needed to reveal practical algorithms for solving large problems quickly. To encourage future research, we sketch some alternative methods of analysis that rely on the structure of MDPs.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:36 GMT" } ]
1,361,404,800,000
[ [ "Littman", "Michael L.", "" ], [ "Dean", "Thomas L.", "" ], [ "Kaelbling", "Leslie Pack", "" ] ]
1302.4972
Christopher Meek
Christopher Meek
Causal Inference and Causal Explanation with Background Knowledge
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-403-410
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents correct algorithms for answering the following two questions; (i) Does there exist a causal explanation consistent with a set of background knowledge which explains all of the observed independence facts in a sample? (ii) Given that there is such a causal explanation what are the causal relationships common to every such causal explanation?
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:41 GMT" } ]
1,361,404,800,000
[ [ "Meek", "Christopher", "" ] ]
1302.4973
Christopher Meek
Christopher Meek
Strong Completeness and Faithfulness in Bayesian Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-411-418
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A completeness result for d-separation applied to discrete Bayesian networks is presented and it is shown that in a strong measure-theoretic sense almost all discrete distributions for a given network structure are faithful; i.e. the independence facts true of the distribution are all and only those entailed by the network structure.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:46 GMT" } ]
1,361,404,800,000
[ [ "Meek", "Christopher", "" ] ]
1302.4974
Liem Ngo
Liem Ngo, Peter Haddawy, James Helwig
A Theoretical Framework for Context-Sensitive Temporal Probability Model Construction with Application to Plan Projection
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-419-426
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We define a context-sensitive temporal probability logic for representing classes of discrete-time temporal Bayesian networks. Context constraints allow inference to be focused on only the relevant portions of the probabilistic knowledge. We provide a declarative semantics for our language. We present a Bayesian network construction algorithm whose generated networks give sound and complete answers to queries. We use related concepts in logic programming to justify our approach. We have implemented a Bayesian network construction algorithm for a subset of the theory and demonstrate it's application to the problem of evaluating the effectiveness of treatments for acute cardiac conditions.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:52 GMT" } ]
1,361,404,800,000
[ [ "Ngo", "Liem", "" ], [ "Haddawy", "Peter", "" ], [ "Helwig", "James", "" ] ]
1302.4975
Simon Parsons
Simon Parsons
Refining Reasoning in Qualitative Probabilistic Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-427-434
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years there has been a spate of papers describing systems for probabilisitic reasoning which do not use numerical probabilities. In some cases the simple set of values used by these systems make it impossible to predict how a probability will change or which hypothesis is most likely given certain evidence. This paper concentrates on such situations, and suggests a number of ways in which they may be resolved by refining the representation.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:22:58 GMT" } ]
1,361,404,800,000
[ [ "Parsons", "Simon", "" ] ]
1302.4976
Judea Pearl
Judea Pearl
On the Testability of Causal Models with Latent and Instrumental Variables
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-435-443
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Certain causal models involving unmeasured variables induce no independence constraints among the observed variables but imply, nevertheless, inequality contraints on the observed distribution. This paper derives a general formula for such instrumental variables, that is, exogenous variables that directly affect some variables but not all. With the help of this formula, it is possible to test whether a model involving instrumental variables may account for the data, or, conversely, whether a given variables can be deemed instrumental.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:04 GMT" } ]
1,361,404,800,000
[ [ "Pearl", "Judea", "" ] ]
1302.4977
Judea Pearl
Judea Pearl, James M. Robins
Probabilistic Evaluation of Sequential Plans from Causal Models with Hidden Variables
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-444-453
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The paper concerns the probabilistic evaluation of plans in the presence of unmeasured variables, each plan consisting of several concurrent or sequential actions. We establish a graphical criterion for recognizing when the effects of a given plan can be predicted from passive observations on measured variables only. When the criterion is satisfied, a closed-form expression is provided for the probability that the plan will achieve a specified goal.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:09 GMT" } ]
1,361,404,800,000
[ [ "Pearl", "Judea", "" ], [ "Robins", "James M.", "" ] ]
1302.4978
David L Poole
David L. Poole
Exploiting the Rule Structure for Decision Making within the Independent Choice Logic
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-454-463
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper introduces the independent choice logic, and in particular the "single agent with nature" instance of the independent choice logic, namely ICLdt. This is a logical framework for decision making uncertainty that extends both logic programming and stochastic models such as influence diagrams. This paper shows how the representation of a decision problem within the independent choice logic can be exploited to cut down the combinatorics of dynamic programming. One of the main problems with influence diagram evaluation techniques is the need to optimise a decision for all values of the 'parents' of a decision variable. In this paper we show how the rule based nature of the ICLdt can be exploited so that we only make distinctions in the values of the information available for a decision that will make a difference to utility.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:14 GMT" } ]
1,361,404,800,000
[ [ "Poole", "David L.", "" ] ]
1302.4979
Gregory M. Provan
Gregory M. Provan
Abstraction in Belief Networks: The Role of Intermediate States in Diagnostic Reasoning
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-464-473
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian belief networks are bing increasingly used as a knowledge representation for diagnostic reasoning. One simple method for conducting diagnostic reasoning is to represent system faults and observations only. In this paper, we investigate how having intermediate nodes-nodes other than fault and observation nodes affects the diagnostic performance of a Bayesian belief network. We conducted a series of experiments on a set of real belief networks for medical diagnosis in liver and bile disease. We compared the effects on diagnostic performance of a two-level network consisting just of disease and finding nodes with that of a network which models intermediate pathophysiological disease states as well. We provide some theoretical evidence for differences observed between the abstracted two-level network and the full network.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:19 GMT" } ]
1,361,404,800,000
[ [ "Provan", "Gregory M.", "" ] ]
1302.4980
David V. Pynadath
David V. Pynadath, Michael P. Wellman
Accounting for Context in Plan Recognition, with Application to Traffic Monitoring
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-472-481
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Typical approaches to plan recognition start from a representation of an agent's possible plans, and reason evidentially from observations of the agent's actions to assess the plausibility of the various candidates. A more expansive view of the task (consistent with some prior work) accounts for the context in which the plan was generated, the mental state and planning process of the agent, and consequences of the agent's actions in the world. We present a general Bayesian framework encompassing this view, and focus on how context can be exploited in plan recognition. We demonstrate the approach on a problem in traffic monitoring, where the objective is to induce the plan of the driver from observation of vehicle movements. Starting from a model of how the driver generates plans, we show how the highway context can appropriately influence the recognizer's interpretation of observed driver behavior.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:24 GMT" } ]
1,361,404,800,000
[ [ "Pynadath", "David V.", "" ], [ "Wellman", "Michael P.", "" ] ]
1302.4981
Prakash P. Shenoy
Prakash P. Shenoy
A New Pruning Method for Solving Decision Trees and Game Trees
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-482-490
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The main goal of this paper is to describe a new pruning method for solving decision trees and game trees. The pruning method for decision trees suggests a slight variant of decision trees that we call scenario trees. In scenario trees, we do not need a conditional probability for each edge emanating from a chance node. Instead, we require a joint probability for each path from the root node to a leaf node. We compare the pruning method to the traditional rollback method for decision trees and game trees. For problems that require Bayesian revision of probabilities, a scenario tree representation with the pruning method is more efficient than a decision tree representation with the rollback method. For game trees, the pruning method is more efficient than the rollback method.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:29 GMT" } ]
1,361,404,800,000
[ [ "Shenoy", "Prakash P.", "" ] ]
1302.4982
Peter L. Spirtes
Peter L. Spirtes
Directed Cyclic Graphical Representations of Feedback Models
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-491-498
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The use of directed acyclic graphs (DAGs) to represent conditional independence relations among random variables has proved fruitful in a variety of ways. Recursive structural equation models are one kind of DAG model. However, non-recursive structural equation models of the kinds used to model economic processes are naturally represented by directed cyclic graphs with independent errors, a characterization of conditional independence errors, a characterization of conditional independence constraints is obtained, and it is shown that the result generalizes in a natural way to systems in which the error variables or noises are statistically dependent. For non-linear systems with independent errors a sufficient condition for conditional independence of variables in associated distributions is obtained.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:34 GMT" } ]
1,361,404,800,000
[ [ "Spirtes", "Peter L.", "" ] ]
1302.4983
Peter L. Spirtes
Peter L. Spirtes, Christopher Meek, Thomas S. Richardson
Causal Inference in the Presence of Latent Variables and Selection Bias
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-499-506
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that there is a general, informative and reliable procedure for discovering causal relations when, for all the investigator knows, both latent variables and selection bias may be at work. Given information about conditional independence and dependence relations between measured variables, even when latent variables and selection bias may be present, there are sufficient conditions for reliably concluding that there is a causal path from one variable to another, and sufficient conditions for reliably concluding when no such causal path exists.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:38 GMT" } ]
1,361,404,800,000
[ [ "Spirtes", "Peter L.", "" ], [ "Meek", "Christopher", "" ], [ "Richardson", "Thomas S.", "" ] ]
1302.4984
Sampath Srinivas
Sampath Srinivas
Modeling Failure Priors and Persistence in Model-Based Diagnosis
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-507-514
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Probabilistic model-based diagnosis computes the posterior probabilities of failure of components from the prior probabilities of component failure and observations of system behavior. One problem with this method is that such priors are almost never directly available. One of the reasons is that the prior probability estimates include an implicit notion of a time interval over which they are specified -- for example, if the probability of failure of a component is 0.05, is this over the period of a day or is this over a week? A second problem facing probabilistic model-based diagnosis is the modeling of persistence. Say we have an observation about a system at time t_1 and then another observation at a later time t_2. To compute posterior probabilities that take into account both the observations, we need some model of how the state of the system changes from time t_1 to t_2. In this paper, we address these problems using techniques from Reliability theory. We show how to compute the failure prior of a component from an empirical measure of its reliability -- the Mean Time Between Failure (MTBF). We also develop a scheme to model persistence when handling multiple time tagged observations.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:43 GMT" } ]
1,361,404,800,000
[ [ "Srinivas", "Sampath", "" ] ]
1302.4985
Sampath Srinivas
Sampath Srinivas
A Polynomial Algorithm for Computing the Optimal Repair Strategy in a System with Independent Component Failures
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-515-522
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The goal of diagnosis is to compute good repair strategies in response to anomalous system behavior. In a decision theoretic framework, a good repair strategy has low expected cost. In a general formulation of the problem, the computation of the optimal (lowest expected cost) repair strategy for a system with multiple faults is intractable. In this paper, we consider an interesting and natural restriction on the behavior of the system being diagnosed: (a) the system exhibits faulty behavior if and only if one or more components is malfunctioning. (b) The failures of the system components are independent. Given this restriction on system behavior, we develop a polynomial time algorithm for computing the optimal repair strategy. We then go on to introduce a system hierarchy and the notion of inspecting (testing) components before repair. We develop a linear time algorithm for computing an optimal repair strategy for the hierarchical system which includes both repair and inspection.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:48 GMT" } ]
1,361,404,800,000
[ [ "Srinivas", "Sampath", "" ] ]
1302.4986
Sampath Srinivas
Sampath Srinivas, Eric J. Horvitz
Exploiting System Hierarchy to Compute Repair Plans in Probabilistic Model-based Diagnosis
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-523-531
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The goal of model-based diagnosis is to isolate causes of anomalous system behavior and recommend inexpensive repair actions in response. In general, precomputing optimal repair policies is intractable. To date, investigators addressing this problem have explored approximations that either impose restrictions on the system model (such as a single fault assumption) or compute an immediate best action with limited lookahead. In this paper, we develop a formulation of repair in model-based diagnosis and a repair algorithm that computes optimal sequences of actions. This optimal approach is costly but can be applied to precompute an optimal repair strategy for compact systems. We show how we can exploit a hierarchical system specification to make this approach tractable for large systems. When introducing hierarchy, we also consider the tradeoff between simply replacing a component and decomposing it to repair its subcomponents. The hierarchical repair algorithm is suitable for off-line precomputation of an optimal repair strategy. A modification of the algorithm takes advantage of an iterative deepening scheme to trade off inference time and the quality of the computed strategy.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:23:54 GMT" } ]
1,361,404,800,000
[ [ "Srinivas", "Sampath", "" ], [ "Horvitz", "Eric J.", "" ] ]
1302.4987
Michael P. Wellman
Michael P. Wellman, Matthew Ford, Kenneth Larson
Path Planning under Time-Dependent Uncertainty
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-532-539
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Standard algorithms for finding the shortest path in a graph require that the cost of a path be additive in edge costs, and typically assume that costs are deterministic. We consider the problem of uncertain edge costs, with potential probabilistic dependencies among the costs. Although these dependencies violate the standard dynamic-programming decomposition, we identify a weaker stochastic consistency condition that justifies a generalized dynamic-programming approach based on stochastic dominance. We present a revised path-planning algorithm and prove that it produces optimal paths under time-dependent uncertain costs. We test the algorithm by applying it to a model of stochastic bus networks, and present empirical performance results comparing it to some alternatives. Finally, we consider extensions of these concepts to a more general class of problems of heuristic search under uncertainty.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:00 GMT" } ]
1,361,404,800,000
[ [ "Wellman", "Michael P.", "" ], [ "Ford", "Matthew", "" ], [ "Larson", "Kenneth", "" ] ]
1302.4988
Emil Weydert
Emil Weydert
Defaults and Infinitesimals: Defeasible Inference by Nonarchimedean Entropy-Maximization
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-540-547
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We develop a new semantics for defeasible inference based on extended probability measures allowed to take infinitesimal values, on the interpretation of defaults as generalized conditional probability constraints and on a preferred-model implementation of entropy maximization.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:05 GMT" } ]
1,361,404,800,000
[ [ "Weydert", "Emil", "" ] ]
1302.4989
Nic Wilson
Nic Wilson
An Order of Magnitude Calculus
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-548-555
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper develops a simple calculus for order of magnitude reasoning. A semantics is given with soundness and completeness results. Order of magnitude probability functions are easily defined and turn out to be equivalent to kappa functions, which are slight generalizations of Spohn's Natural Conditional Functions. The calculus also gives rise to an order of magnitude decision theory, which can be used to justify an amended version of Pearl's decision theory for kappa functions, although the latter is weaker and less expressive.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:11 GMT" } ]
1,361,404,800,000
[ [ "Wilson", "Nic", "" ] ]
1302.4990
Michael S. K. M. Wong
Michael S. K. M. Wong, C. J. Butz, Yang Xiang
A Method for Implementing a Probabilistic Model as a Relational Database
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-556-564
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper discusses a method for implementing a probabilistic inference system based on an extended relational data model. This model provides a unified approach for a variety of applications such as dynamic programming, solving sparse linear equations, and constraint propagation. In this framework, the probability model is represented as a generalized relational database. Subsequent probabilistic requests can be processed as standard relational queries. Conventional database management systems can be easily adopted for implementing such an approximate reasoning system.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:15 GMT" } ]
1,361,404,800,000
[ [ "Wong", "Michael S. K. M.", "" ], [ "Butz", "C. J.", "" ], [ "Xiang", "Yang", "" ] ]
1302.4991
Yang Xiang
Yang Xiang
Optimization of Inter-Subnet Belief Updating in Multiply Sectioned Bayesian Networks
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-565-573
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent developments show that Multiply Sectioned Bayesian Networks (MSBNs) can be used for diagnosis of natural systems as well as for model-based diagnosis of artificial systems. They can be applied to single-agent oriented reasoning systems as well as multi-agent distributed probabilistic reasoning systems. Belief propagation between a pair of subnets plays a central role in maintenance of global consistency in a MSBN. This paper studies the operation UpdateBelief, presented originally with MSBNs, for inter-subnet propagation. We analyze how the operation achieves its intended functionality, which provides hints as for how its efficiency can be improved. We then define two new versions of UpdateBelief that reduce the computation time for inter-subnet propagation. One of them is optimal in the sense that the minimum amount of computation for coordinating multi-linkage belief propagation is required. The optimization problem is solved through the solution of a graph-theoretic problem: the minimum weight open tour in a tree.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:20 GMT" } ]
1,361,404,800,000
[ [ "Xiang", "Yang", "" ] ]
1302.4992
Hong Xu
Hong Xu, Philippe Smets
Generating Explanations for Evidential Reasoning
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-574-581
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we present two methods to provide explanations for reasoning with belief functions in the valuation-based systems. One approach, inspired by Strat's method, is based on sensitivity analysis, but its computation is simpler thus easier to implement than Strat's. The other one is to examine the impact of evidence on the conclusion based on the measure of the information content in the evidence. We show the property of additivity for the pieces of evidence that are conditional independent within the context of the valuation-based systems. We will give an example to show how these approaches are applied in an evidential network.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:26 GMT" } ]
1,361,404,800,000
[ [ "Xu", "Hong", "" ], [ "Smets", "Philippe", "" ] ]
1302.4993
Nevin Lianwen Zhang
Nevin Lianwen Zhang
Inference with Causal Independence in the CPSC Network
Appears in Proceedings of the Eleventh Conference on Uncertainty in Artificial Intelligence (UAI1995)
null
null
UAI-P-1995-PG-582-589
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper reports experiments with the causal independence inference algorithm proposed by Zhang and Poole (1994b) on the CPSC network created by Pradhan et al. (1994). It is found that the algorithm is able to answer 420 of the 422 possible zero-observation queries, 94 of 100 randomly generated five-observation queries, 87 of 100 randomly generated ten-observation queries, and 69 of 100 randomly generated twenty-observation queries.
[ { "version": "v1", "created": "Wed, 20 Feb 2013 15:24:30 GMT" } ]
1,361,404,800,000
[ [ "Zhang", "Nevin Lianwen", "" ] ]
1302.5417
Anandaraj
P. Kalaivani, A. Anandaraj, K. Raja
An Ontology Construction Approach for the Domain Of Poultry Science Using Protege
arXiv admin note: text overlap with arXiv:1302.5215
International Journal of Information Technology and Management Sciences / Volume 1, Issue 2, 2011, ISSN:2231-6752
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The information retrieval systems that are present nowadays are mainly based on full text matching of keywords or topic based classification. This matching of keywords often returns a large number of irrelevant information and this does not meet the users query requirement. In order to solve this problem and to enhance the search using semantic environment, a technique named ontology is implemented for the field of poultry in this paper. Ontology is an emerging technique in the current field of research in semantic environment. This paper constructs ontology using the tool named Protege version 4.0 and this also generates Resource Description Framework schema and XML scripts for using poultry ontology in web.
[ { "version": "v1", "created": "Thu, 21 Feb 2013 09:19:11 GMT" } ]
1,361,750,400,000
[ [ "Kalaivani", "P.", "" ], [ "Anandaraj", "A.", "" ], [ "Raja", "K.", "" ] ]
1302.5824
Min Chen
B. Duffy, A. Dasgupta, R. Kosara, S. Walton and M. Chen
Measuring Visual Complexity of Cluster-Based Visualizations
null
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Handling visual complexity is a challenging problem in visualization owing to the subjectiveness of its definition and the difficulty in devising generalizable quantitative metrics. In this paper we address this challenge by measuring the visual complexity of two common forms of cluster-based visualizations: scatter plots and parallel coordinatess. We conceptualize visual complexity as a form of visual uncertainty, which is a measure of the degree of difficulty for humans to interpret a visual representation correctly. We propose an algorithm for estimating visual complexity for the aforementioned visualizations using Allen's interval algebra. We first establish a set of primitive 2-cluster cases in scatter plots and another set for parallel coordinatess based on symmetric isomorphism. We confirm that both are the minimal sets and verify the correctness of their members computationally. We score the uncertainty of each primitive case based on its topological properties, including the existence of overlapping regions, splitting regions and meeting points or edges. We compare a few optional scoring schemes against a set of subjective scores by humans, and identify the one that is the most consistent with the subjective scores. Finally, we extend the 2-cluster measure to k-cluster measure as a general purpose estimator of visual complexity for these two forms of cluster-based visualization.
[ { "version": "v1", "created": "Sat, 23 Feb 2013 16:34:35 GMT" } ]
1,361,836,800,000
[ [ "Duffy", "B.", "" ], [ "Dasgupta", "A.", "" ], [ "Kosara", "R.", "" ], [ "Walton", "S.", "" ], [ "Chen", "M.", "" ] ]
1302.6214
Alexander Korobeynikov Vasilyevich
A.V. Korobeynikov, I.I. Islamgaliev
Modification of conceptual clustering algorithm Cobweb for numerical data using fuzzy membership function
in Russian
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Modification of a conceptual clustering algorithm Cobweb for the purpose of its application for numerical data is offered. Keywords: clustering, algorithm Cobweb, numerical data, fuzzy membership function.
[ { "version": "v1", "created": "Mon, 25 Feb 2013 20:15:06 GMT" } ]
1,361,836,800,000
[ [ "Korobeynikov", "A. V.", "" ], [ "Islamgaliev", "I. I.", "" ] ]
1302.6442
Alain-J\'er\^ome Foug\`eres
Alain-J\'er\^ome Foug\`eres
A Modelling Approach Based on Fuzzy Agents
10 pages, 8 figures, 35 references
IJCSI-2012-9-6-4655
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Modelling of complex systems is mainly based on the decomposition of these systems in autonomous elements, and the identification and definitio9n of possible interactions between these elements. For this, the agent-based approach is a modelling solution often proposed. Complexity can also be due to external events or internal to systems, whose main characteristics are uncertainty, imprecision, or whose perception is subjective (i.e. interpreted). Insofar as fuzzy logic provides a solution for modelling uncertainty, the concept of fuzzy agent can model both the complexity and uncertainty. This paper focuses on introducing the concept of fuzzy agent: a classical architecture of agent is redefined according to a fuzzy perspective. A pedagogical illustration of fuzzy agentification of a smart watering system is then proposed.
[ { "version": "v1", "created": "Tue, 26 Feb 2013 14:24:36 GMT" } ]
1,361,923,200,000
[ [ "Fougères", "Alain-Jérôme", "" ] ]
1302.6779
Constantin F. Aliferis
Constantin F. Aliferis, Gregory F. Cooper
An Evaluation of an Algorithm for Inductive Learning of Bayesian Belief Networks Usin
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-8-14
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian learning of belief networks (BLN) is a method for automatically constructing belief networks (BNs) from data using search and Bayesian scoring techniques. K2 is a particular instantiation of the method that implements a greedy search strategy. To evaluate the accuracy of K2, we randomly generated a number of BNs and for each of those we simulated data sets. K2 was then used to induce the generating BNs from the simulated data. We examine the performance of the program, and the factors that influence it. We also present a simple BN model, developed from our results, which predicts the accuracy of K2, when given various characteristics of the data set.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:16 GMT" } ]
1,362,009,600,000
[ [ "Aliferis", "Constantin F.", "" ], [ "Cooper", "Gregory F.", "" ] ]
1302.6780
Russ B. Altman
Russ B. Altman, Cheng C. Chen, William B. Poland, Jaswinder Pal Singh
Probabilistic Constraint Satisfaction with Non-Gaussian Noise
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-15-22
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have previously reported a Bayesian algorithm for determining the coordinates of points in three-dimensional space from uncertain constraints. This method is useful in the determination of biological molecular structure. It is limited, however, by the requirement that the uncertainty in the constraints be normally distributed. In this paper, we present an extension of the original algorithm that allows constraint uncertainty to be represented as a mixture of Gaussians, and thereby allows arbitrary constraint distributions. We illustrate the performance of this algorithm on a problem drawn from the domain of molecular structure determination, in which a multicomponent constraint representation produces a much more accurate solution than the old single component mechanism. The new mechanism uses mixture distributions to decompose the problem into a set of independent problems with unimodal constraint uncertainty. The results of the unimodal subproblems are periodically recombined using Bayes' law, to avoid combinatorial explosion. The new algorithm is particularly suited for parallel implementation.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:22 GMT" } ]
1,362,009,600,000
[ [ "Altman", "Russ B.", "" ], [ "Chen", "Cheng C.", "" ], [ "Poland", "William B.", "" ], [ "Singh", "Jaswinder Pal", "" ] ]
1302.6781
Derek D. Ayers
Derek D. Ayers
A Bayesian Method Reexamined
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-23-27
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper examines the "K2" network scoring metric of Cooper and Herskovits. It shows counterintuitive results from applying this metric to simple networks. One family of noninformative priors is suggested for assigning equal scores to equivalent networks.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:31 GMT" } ]
1,362,009,600,000
[ [ "Ayers", "Derek D.", "" ] ]
1302.6782
Adriano Azevedo-Filho
Adriano Azevedo-Filho, Ross D. Shachter
Laplace's Method Approximations for Probabilistic Inference in Belief Networks with Continuous Variables
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-28-36
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Laplace's method, a family of asymptotic methods used to approximate integrals, is presented as a potential candidate for the tool box of techniques used for knowledge acquisition and probabilistic inference in belief networks with continuous variables. This technique approximates posterior moments and marginal posterior distributions with reasonable accuracy [errors are O(n^-2) for posterior means] in many interesting cases. The method also seems promising for computing approximations for Bayes factors for use in the context of model selection, model uncertainty and mixtures of pdfs. The limitations, regularity conditions and computational difficulties for the implementation of Laplace's method are comparable to those associated with the methods of maximum likelihood and posterior mode analysis.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:37 GMT" } ]
1,362,009,600,000
[ [ "Azevedo-Filho", "Adriano", "" ], [ "Shachter", "Ross D.", "" ] ]
1302.6783
Fahiem Bacchus
Fahiem Bacchus, Adam J. Grove, Joseph Y. Halpern, Daphne Koller
Generating New Beliefs From Old
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-37-45
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In previous work [BGHK92, BGHK93], we have studied the random-worlds approach -- a particular (and quite powerful) method for generating degrees of belief (i.e., subjective probabilities) from a knowledge base consisting of objective (first-order, statistical, and default) information. But allowing a knowledge base to contain only objective information is sometimes limiting. We occasionally wish to include information about degrees of belief in the knowledge base as well, because there are contexts in which old beliefs represent important information that should influence new beliefs. In this paper, we describe three quite general techniques for extending a method that generates degrees of belief from objective information to one that can make use of degrees of belief as well. All of our techniques are bloused on well-known approaches, such as cross-entropy. We discuss general connections between the techniques and in particular show that, although conceptually and technically quite different, all of the techniques give the same answer when applied to the random-worlds method.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:44 GMT" } ]
1,362,009,600,000
[ [ "Bacchus", "Fahiem", "" ], [ "Grove", "Adam J.", "" ], [ "Halpern", "Joseph Y.", "" ], [ "Koller", "Daphne", "" ] ]
1302.6784
Alexander Balke
Alexander Balke, Judea Pearl
Counterfactual Probabilities: Computational Methods, Bounds and Applications
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-46-54
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Evaluation of counterfactual queries (e.g., "If A were true, would C have been true?") is important to fault diagnosis, planning, and determination of liability. In this paper we present methods for computing the probabilities of such queries using the formulation proposed in [Balke and Pearl, 1994], where the antecedent of the query is interpreted as an external action that forces the proposition A to be true. When a prior probability is available on the causal mechanisms governing the domain, counterfactual probabilities can be evaluated precisely. However, when causal knowledge is specified as conditional probabilities on the observables, only bounds can computed. This paper develops techniques for evaluating these bounds, and demonstrates their use in two applications: (1) the determination of treatment efficacy from studies in which subjects may choose their own treatment, and (2) the determination of liability in product-safety litigation.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:50 GMT" } ]
1,362,009,600,000
[ [ "Balke", "Alexander", "" ], [ "Pearl", "Judea", "" ] ]
1302.6786
Ildar Z. Batyrshin
Ildar Z. Batyrshin
Modus Ponens Generating Function in the Class of ^-valuations of Plausibility
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-55-59
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We discuss the problem of construction of inference procedures which can manipulate with uncertainties measured in ordinal scales and fulfill to the property of strict monotonicity of conclusion. The class of A-valuations of plausibility is considered where operations based only on information about linear ordering of plausibility values are used. In this class the modus ponens generating function fulfiling to the property of strict monotonicity of conclusions is introduced.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:13:56 GMT" } ]
1,362,009,600,000
[ [ "Batyrshin", "Ildar Z.", "" ] ]
1302.6788
Philippe Besnard
Philippe Besnard, Jerome Lang
Possibility and Necessity Functions over Non-classical Logics
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-69-76
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an integration of possibility theory into non-classical logics. We obtain many formal results that generalize the case where possibility and necessity functions are based on classical logic. We show how useful such an approach is by applying it to reasoning under uncertain and inconsistent information.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:08 GMT" } ]
1,362,009,600,000
[ [ "Besnard", "Philippe", "" ], [ "Lang", "Jerome", "" ] ]
1302.6789
Raj Bhatnagar
Raj Bhatnagar
Exploratory Model Building
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-77-85
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Some instances of creative thinking require an agent to build and test hypothetical theories. Such a reasoner needs to explore the space of not only those situations that have occurred in the past, but also those that are rationally conceivable. In this paper we present a formalism for exploring the space of conceivable situation-models for those domains in which the knowledge is primarily probabilistic in nature. The formalism seeks to construct consistent, minimal, and desirable situation-descriptions by selecting suitable domain-attributes and dependency relationships from the available domain knowledge.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:14 GMT" } ]
1,362,009,600,000
[ [ "Bhatnagar", "Raj", "" ] ]
1302.6791
Jim S. Blythe
Jim S. Blythe
Planning with External Events
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-94-101
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
I describe a planning methodology for domains with uncertainty in the form of external events that are not completely predictable. The events are represented by enabling conditions and probabilities of occurrence. The planner is goal-directed and backward chaining, but the subgoals are suggested by analyzing the probability of success of the partial plan rather than being simply the open conditions of the operators in the plan. The partial plan is represented as a Bayesian belief net to compute its probability of success. Since calculating the probability of success of a plan can be very expensive I introduce two other techniques for computing it, one that uses Monte Carlo simulation to estimate it and one based on a Markov chain representation that uses knowledge about the dependencies between the predicates describing the domain.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:26 GMT" } ]
1,362,009,600,000
[ [ "Blythe", "Jim S.", "" ] ]
1302.6792
Remco R. Bouckaert
Remco R. Bouckaert
Properties of Bayesian Belief Network Learning Algorithms
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-102-109
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian belief network learning algorithms have three basic components: a measure of a network structure and a database, a search heuristic that chooses network structures to be considered, and a method of estimating the probability tables from the database. This paper contributes to all these three topics. The behavior of the Bayesian measure of Cooper and Herskovits and a minimum description length (MDL) measure are compared with respect to their properties for both limiting size and finite size databases. It is shown that the MDL measure has more desirable properties than the Bayesian measure when a distribution is to be learned. It is shown that selecting belief networks with certain minimallity properties is NP-hard. This result justifies the use of search heuristics instead of exact algorithms for choosing network structures to be considered. In some cases, a collection of belief networks can be represented by a single belief network which leads to a new kind of probability table estimation called smoothing. We argue that smoothing can be efficiently implemented by incorporating it in the search heuristic. Experimental results suggest that for learning probabilities of belief networks smoothing is helpful.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:31 GMT" } ]
1,362,009,600,000
[ [ "Bouckaert", "Remco R.", "" ] ]
1302.6793
Remco R. Bouckaert
Remco R. Bouckaert
A Stratified Simulation Scheme for Inference in Bayesian Belief Networks
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-110-118
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Simulation schemes for probabilistic inference in Bayesian belief networks offer many advantages over exact algorithms; for example, these schemes have a linear and thus predictable runtime while exact algorithms have exponential runtime. Experiments have shown that likelihood weighting is one of the most promising simulation schemes. In this paper, we present a new simulation scheme that generates samples more evenly spread in the sample space than the likelihood weighting scheme. We show both theoretically and experimentally that the stratified scheme outperforms likelihood weighting in average runtime and error in estimates of beliefs.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:37 GMT" } ]
1,362,009,600,000
[ [ "Bouckaert", "Remco R.", "" ] ]
1302.6794
Tom Chavez
Tom Chavez, Max Henrion
Efficient Estimation of the Value of Information in Monte Carlo Models
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-119-127
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The expected value of information (EVI) is the most powerful measure of sensitivity to uncertainty in a decision model: it measures the potential of information to improve the decision, and hence measures the expected value of outcome. Standard methods for computing EVI use discrete variables and are computationally intractable for models that contain more than a few variables. Monte Carlo simulation provides the basis for more tractable evaluation of large predictive models with continuous and discrete variables, but so far computation of EVI in a Monte Carlo setting also has appeared impractical. We introduce an approximate approach based on pre-posterior analysis for estimating EVI in Monte Carlo models. Our method uses a linear approximation to the value function and multiple linear regression to estimate the linear model from the samples. The approach is efficient and practical for extremely large models. It allows easy estimation of EVI for perfect or partial information on individual variables or on combinations of variables. We illustrate its implementation within Demos (a decision modeling system), and its application to a large model for crisis transportation planning.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:43 GMT" } ]
1,362,009,600,000
[ [ "Chavez", "Tom", "" ], [ "Henrion", "Max", "" ] ]
1302.6795
Bruce D'Ambrosio
Bruce D'Ambrosio
Symbolic Probabilitistic Inference in Large BN2O Networks
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-128-135
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A BN2O network is a two level belief net in which the parent interactions are modeled using the noisy-or interaction model. In this paper we discuss application of the SPI local expression language to efficient inference in large BN2O networks. In particular, we show that there is significant structure, which can be exploited to improve over the Quickscore result. We further describe how symbolic techniques can provide information which can significantly reduce the computation required for computing all cause posterior marginals. Finally, we present a novel approximation technique with preliminary experimental results.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:49 GMT" } ]
1,362,009,600,000
[ [ "D'Ambrosio", "Bruce", "" ] ]
1302.6796
Adnan Darwiche
Adnan Darwiche, Moises Goldszmidt
Action Networks: A Framework for Reasoning about Actions and Change under Uncertainty
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-136-144
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work proposes action networks as a semantically well-founded framework for reasoning about actions and change under uncertainty. Action networks add two primitives to probabilistic causal networks: controllable variables and persistent variables. Controllable variables allow the representation of actions as directly setting the value of specific events in the domain, subject to preconditions. Persistent variables provide a canonical model of persistence according to which both the state of a variable and the causal mechanism dictating its value persist over time unless intervened upon by an action (or its consequences). Action networks also allow different methods for quantifying the uncertainty in causal relationships, which go beyond traditional probabilistic quantification. This paper describes both recent results and work in progress.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:14:55 GMT" } ]
1,362,009,600,000
[ [ "Darwiche", "Adnan", "" ], [ "Goldszmidt", "Moises", "" ] ]
1302.6797
Adnan Darwiche
Adnan Darwiche, Moises Goldszmidt
On the Relation between Kappa Calculus and Probabilistic Reasoning
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-145-153
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the connection between kappa calculus and probabilistic reasoning in diagnosis applications. Specifically, we abstract a probabilistic belief network for diagnosing faults into a kappa network and compare the ordering of faults computed using both methods. We show that, at least for the example examined, the ordering of faults coincide as long as all the causal relations in the original probabilistic network are taken into account. We also provide a formal analysis of some network structures where the two methods will differ. Both kappa rankings and infinitesimal probabilities have been used extensively to study default reasoning and belief revision. But little has been done on utilizing their connection as outlined above. This is partly because the relation between kappa and probability calculi assumes that probabilities are arbitrarily close to one (or zero). The experiments in this paper investigate this relation when this assumption is not satisfied. The reported results have important implications on the use of kappa rankings to enhance the knowledge engineering of uncertainty models.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:01 GMT" } ]
1,362,009,600,000
[ [ "Darwiche", "Adnan", "" ], [ "Goldszmidt", "Moises", "" ] ]
1302.6798
Ron Davidson
Ron Davidson, Michael R. Fehling
A Structured, Probabilistic Representation of Action
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-154-161
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
When agents devise plans for execution in the real world, they face two important forms of uncertainty: they can never have complete knowledge about the state of the world, and they do not have complete control, as the effects of their actions are uncertain. While most classical planning methods avoid explicit uncertainty reasoning, we believe that uncertainty should be explicitly represented and reasoned about. We develop a probabilistic representation for states and actions, based on belief networks. We define conditional belief nets (CBNs) to capture the probabilistic dependency of the effects of an action upon the state of the world. We also use a CBN to represent the intrinsic relationships among entities in the environment, which persist from state to state. We present a simple projection algorithm to construct the belief network of the state succeeding an action, using the environment CBN model to infer indirect effects. We discuss how the qualitative aspects of belief networks and CBNs make them appropriate for the various stages of the problem solving process, from model construction to the design of planning algorithms.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:07 GMT" } ]
1,362,009,600,000
[ [ "Davidson", "Ron", "" ], [ "Fehling", "Michael R.", "" ] ]
1302.6799
Richard Dearden
Richard Dearden, Craig Boutilier
Integrating Planning and Execution in Stochastic Domains
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-162-169
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate planning in time-critical domains represented as Markov Decision Processes, showing that search based techniques can be a very powerful method for finding close to optimal plans. To reduce the computational cost of planning in these domains, we execute actions as we construct the plan, and sacrifice optimality by searching to a fixed depth and using a heuristic function to estimate the value of states. Although this paper concentrates on the search algorithm, we also discuss ways of constructing heuristic functions suitable for this approach. Our results show that by interleaving search and execution, close to optimal policies can be found without the computational requirements of other approaches.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:13 GMT" } ]
1,362,009,600,000
[ [ "Dearden", "Richard", "" ], [ "Boutilier", "Craig", "" ] ]
1302.6800
Denise L. Draper
Denise L. Draper, Steve Hanks
Localized Partial Evaluation of Belief Networks
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-170-177
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Most algorithms for propagating evidence through belief networks have been exact and exhaustive: they produce an exact (point-valued) marginal probability for every node in the network. Often, however, an application will not need information about every n ode in the network nor will it need exact probabilities. We present the localized partial evaluation (LPE) propagation algorithm, which computes interval bounds on the marginal probability of a specified query node by examining a subset of the nodes in the entire network. Conceptually, LPE ignores parts of the network that are "too far away" from the queried node to have much impact on its value. LPE has the "anytime" property of being able to produce better solutions (tighter intervals) given more time to consider more of the network.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:20 GMT" } ]
1,362,009,600,000
[ [ "Draper", "Denise L.", "" ], [ "Hanks", "Steve", "" ] ]
1302.6801
Denise L. Draper
Denise L. Draper, Steve Hanks, Daniel Weld
A Probabilistic Model of Action for Least-Commitment Planning with Information Gather
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-178-186
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
AI planning algorithms have addressed the problem of generating sequences of operators that achieve some input goal, usually assuming that the planning agent has perfect control over and information about the world. Relaxing these assumptions requires an extension to the action representation that allows reasoning both about the changes an action makes and the information it provides. This paper presents an action representation that extends the deterministic STRIPS model, allowing actions to have both causal and informational effects, both of which can be context dependent and noisy. We also demonstrate how a standard least-commitment planning algorithm can be extended to include informational actions and contingent execution.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:26 GMT" } ]
1,362,009,600,000
[ [ "Draper", "Denise L.", "" ], [ "Hanks", "Steve", "" ], [ "Weld", "Daniel", "" ] ]
1302.6802
Marek J. Druzdzel
Marek J. Druzdzel
Some Properties of Joint Probability Distributions
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-187-194
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Several Artificial Intelligence schemes for reasoning under uncertainty explore either explicitly or implicitly asymmetries among probabilities of various states of their uncertain domain models. Even though the correct working of these schemes is practically contingent upon the existence of a small number of probable states, no formal justification has been proposed of why this should be the case. This paper attempts to fill this apparent gap by studying asymmetries among probabilities of various states of uncertain models. By rewriting the joint probability distribution over a model's variables into a product of individual variables' prior and conditional probability distributions, and applying central limit theorem to this product, we can demonstrate that the probabilities of individual states of the model can be expected to be drawn from highly skewed, log-normal distributions. With sufficient asymmetry in individual prior and conditional probability distributions, a small fraction of states can be expected to cover a large portion of the total probability space with the remaining states having practically negligible probability. Theoretical discussion is supplemented by simulation results and an illustrative real-world example.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:32 GMT" } ]
1,362,009,600,000
[ [ "Druzdzel", "Marek J.", "" ] ]
1302.6803
Didier Dubois
Didier Dubois, Luis Farinas del Cerro, Andreas Herzig, Henri Prade
An Ordinal View of Independence with Application to Plausible Reasoning
Appears in Proceedings of the Tenth Conference on Uncertainty in Artificial Intelligence (UAI1994)
null
null
UAI-P-1994-PG-195-203
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An ordinal view of independence is studied in the framework of possibility theory. We investigate three possible definitions of dependence, of increasing strength. One of them is the counterpart to the multiplication law in probability theory, and the two others are based on the notion of conditional possibility. These two have enough expressive power to support the whole possibility theory, and a complete axiomatization is provided for the strongest one. Moreover we show that weak independence is well-suited to the problems of belief change and plausible reasoning, especially to address the problem of blocking of property inheritance in exception-tolerant taxonomic reasoning.
[ { "version": "v1", "created": "Wed, 27 Feb 2013 14:15:38 GMT" } ]
1,362,009,600,000
[ [ "Dubois", "Didier", "" ], [ "del Cerro", "Luis Farinas", "" ], [ "Herzig", "Andreas", "" ], [ "Prade", "Henri", "" ] ]