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1303.5741
Arthur Ramer
Arthur Ramer
Formal Model of Uncertainty for Possibilistic Rules
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-295-299
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Given a universe of discourse X-a domain of possible outcomes-an experiment may consist of selecting one of its elements, subject to the operation of chance, or of observing the elements, subject to imprecision. A priori uncertainty about the actual result of the experiment may be quantified, representing either the likelihood of the choice of :r_X or the degree to which any such X would be suitable as a description of the outcome. The former case corresponds to a probability distribution, while the latter gives a possibility assignment on X. The study of such assignments and their properties falls within the purview of possibility theory [DP88, Y80, Z783. It, like probability theory, assigns values between 0 and 1 to express likelihoods of outcomes. Here, however, the similarity ends. Possibility theory uses the maximum and minimum functions to combine uncertainties, whereas probability theory uses the plus and times operations. This leads to very dissimilar theories in terms of analytical framework, even though they share several semantic concepts. One of the shared concepts consists of expressing quantitatively the uncertainty associated with a given distribution. In probability theory its value corresponds to the gain of information that would result from conducting an experiment and ascertaining an actual result. This gain of information can equally well be viewed as a decrease in uncertainty about the outcome of an experiment. In this case the standard measure of information, and thus uncertainty, is Shannon entropy [AD75, G77]. It enjoys several advantages-it is characterized uniquely by a few, very natural properties, and it can be conveniently used in decision processes. This application is based on the principle of maximum entropy; it has become a popular method of relating decisions to uncertainty. This paper demonstrates that an equally integrated theory can be built on the foundation of possibility theory. We first show how to define measures of in formation and uncertainty for possibility assignments. Next we construct an information-based metric on the space of all possibility distributions defined on a given domain. It allows us to capture the notion of proximity in information content among the distributions. Lastly, we show that all the above constructions can be carried out for continuous distributions-possibility assignments on arbitrary measurable domains. We consider this step very significant-finite domains of discourse are but approximations of the real-life infinite domains. If possibility theory is to represent real world situations, it must handle continuous distributions both directly and through finite approximations. In the last section we discuss a principle of maximum uncertainty for possibility distributions. We show how such a principle could be formalized as an inference rule. We also suggest it could be derived as a consequence of simple assumptions about combining information. We would like to mention that possibility assignments can be viewed as fuzzy sets and that every fuzzy set gives rise to an assignment of possibilities. This correspondence has far reaching consequences in logic and in control theory. Our treatment here is independent of any special interpretation; in particular we speak of possibility distributions and possibility measures, defining them as measurable mappings into the interval [0, 1]. Our presentation is intended as a self-contained, albeit terse summary. Topics discussed were selected with care, to demonstrate both the completeness and a certain elegance of the theory. Proofs are not included; we only offer illustrative examples.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:32:37 GMT" } ]
1,364,256,000,000
[ [ "Ramer", "Arthur", "" ] ]
1303.5742
Anand S. Rao
Anand S. Rao, Michael P. Georgeff
Deliberation and its Role in the Formation of Intentions
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-300-307
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deliberation plays an important role in the design of rational agents embedded in the real-world. In particular, deliberation leads to the formation of intentions, i.e., plans of action that the agent is committed to achieving. In this paper, we present a branching time possible-worlds model for representing and reasoning about, beliefs, goals, intentions, time, actions, probabilities, and payoffs. We compare this possible-worlds approach with the more traditional decision tree representation and provide a transformation from decision trees to possible worlds. Finally, we illustrate how an agent can perform deliberation using a decision-tree representation and then use a possible-worlds model to form and reason about his intentions.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:32:42 GMT" } ]
1,364,256,000,000
[ [ "Rao", "Anand S.", "" ], [ "Georgeff", "Michael P.", "" ] ]
1303.5743
Bhavani Raskutti
Bhavani Raskutti, Ingrid Zukerman
Handling Uncertainty during Plan Recognition in Task-Oriented Consultation Systems
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-308-315
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
During interactions with human consultants, people are used to providing partial and/or inaccurate information, and still be understood and assisted. We attempt to emulate this capability of human consultants; in computer consultation systems. In this paper, we present a mechanism for handling uncertainty in plan recognition during task-oriented consultations. The uncertainty arises while choosing an appropriate interpretation of a user?s statements among many possible interpretations. Our mechanism handles this uncertainty by using probability theory to assess the probabilities of the interpretations, and complements this assessment by taking into account the information content of the interpretations. The information content of an interpretation is a measure of how well defined an interpretation is in terms of the actions to be performed on the basis of the interpretation. This measure is used to guide the inference process towards interpretations with a higher information content. The information content for an interpretation depends on the specificity and the strength of the inferences in it, where the strength of an inference depends on the reliability of the information on which the inference is based. Our mechanism has been developed for use in task-oriented consultation systems. The domain that we have chosen for exploration is that of a travel agency.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:32:47 GMT" } ]
1,364,256,000,000
[ [ "Raskutti", "Bhavani", "" ], [ "Zukerman", "Ingrid", "" ] ]
1303.5744
Enrique H. Ruspini
Enrique H. Ruspini
Truth as Utility: A Conceptual Synthesis
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-316-322
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper introduces conceptual relations that synthesize utilitarian and logical concepts, extending the logics of preference of Rescher. We define first, in the context of a possible worlds model, constraint-dependent measures that quantify the relative quality of alternative solutions of reasoning problems or the relative desirability of various policies in control, decision, and planning problems. We show that these measures may be interpreted as truth values in a multi valued logic and propose mechanisms for the representation of complex constraints as combinations of simpler restrictions. These extended logical operations permit also the combination and aggregation of goal-specific quality measures into global measures of utility. We identify also relations that represent differential preferences between alternative solutions and relate them to the previously defined desirability measures. Extending conventional modal logic formulations, we introduce structures for the representation of ignorance about the utility of alternative solutions. Finally, we examine relations between these concepts and similarity based semantic models of fuzzy logic.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:32:53 GMT" } ]
1,364,256,000,000
[ [ "Ruspini", "Enrique H.", "" ] ]
1303.5745
Alessandro Saffiotti
Alessandro Saffiotti, Elisabeth Umkehrer
Pulcinella: A General Tool for Propagating Uncertainty in Valuation Networks
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-323-331
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present PULCinella and its use in comparing uncertainty theories. PULCinella is a general tool for Propagating Uncertainty based on the Local Computation technique of Shafer and Shenoy. It may be specialized to different uncertainty theories: at the moment, Pulcinella can propagate probabilities, belief functions, Boolean values, and possibilities. Moreover, Pulcinella allows the user to easily define his own specializations. To illustrate Pulcinella, we analyze two examples by using each of the four theories above. In the first one, we mainly focus on intrinsic differences between theories. In the second one, we take a knowledge engineer viewpoint, and check the adequacy of each theory to a given problem.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:32:58 GMT" } ]
1,364,256,000,000
[ [ "Saffiotti", "Alessandro", "" ], [ "Umkehrer", "Elisabeth", "" ] ]
1303.5746
Sandra Sandri
Sandra Sandri
Structuring Bodies of Evidence
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-332-338
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article we present two ways of structuring bodies of evidence, which allow us to reduce the complexity of the operations usually performed in the framework of evidence theory. The first structure just partitions the focal elements in a body of evidence by their cardinality. With this structure we are able to reduce the complexity on the calculation of the belief functions Bel, Pl, and Q. The other structure proposed here, the Hierarchical Trees, permits us to reduce the complexity of the calculation of Bel, Pl, and Q, as well as of the Dempster's rule of combination in relation to the brute-force algorithm. Both these structures do not require the generation of all the subsets of the reference domain.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:02 GMT" } ]
1,364,256,000,000
[ [ "Sandri", "Sandra", "" ] ]
1303.5747
Eugene Santos Jr.
Eugene Santos Jr
On the Generation of Alternative Explanations with Implications for Belief Revision
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-339-347
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In general, the best explanation for a given observation makes no promises on how good it is with respect to other alternative explanations. A major deficiency of message-passing schemes for belief revision in Bayesian networks is their inability to generate alternatives beyond the second best. In this paper, we present a general approach based on linear constraint systems that naturally generates alternative explanations in an orderly and highly efficient manner. This approach is then applied to cost-based abduction problems as well as belief revision in Bayesian net works.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:07 GMT" } ]
1,364,256,000,000
[ [ "Santos", "Eugene", "Jr" ] ]
1303.5748
Kerstin Schill
Kerstin Schill, Ernst Poppel, Christoph Zetzsche
Completing Knowledge by Competing Hierarchies
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-348-352
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A control strategy for expert systems is presented which is based on Shafer's Belief theory and the combination rule of Dempster. In contrast to well known strategies it is not sequentially and hypotheses-driven, but parallel and self organizing, determined by the concept of information gain. The information gain, calculated as the maximal difference between the actual evidence distribution in the knowledge base and the potential evidence determines each consultation step. Hierarchically structured knowledge is an important representation form and experts even use several hierarchies in parallel for constituting their knowledge. Hence the control strategy is applied to a layered set of distinct hierarchies. Depending on the actual data one of these hierarchies is chosen by the control strategy for the next step in the reasoning process. Provided the actual data are well matched to the structure of one hierarchy, this hierarchy remains selected for a longer consultation time. If no good match can be achieved, a switch from the actual hierarchy to a competing one will result, very similar to the phenomenon of restructuring in problem solving tasks. Up to now the control strategy is restricted to multi hierarchical knowledge bases with disjunct hierarchies. It is implemented in the expert system IBIG (inference by information gain), being presently applied to acquired speech disorders (aphasia).
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:12 GMT" } ]
1,364,256,000,000
[ [ "Schill", "Kerstin", "" ], [ "Poppel", "Ernst", "" ], [ "Zetzsche", "Christoph", "" ] ]
1303.5749
Ross D. Shachter
Ross D. Shachter
A Graph-Based Inference Method for Conditional Independence
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-353-360
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The graphoid axioms for conditional independence, originally described by Dawid [1979], are fundamental to probabilistic reasoning [Pearl, 19881. Such axioms provide a mechanism for manipulating conditional independence assertions without resorting to their numerical definition. This paper explores a representation for independence statements using multiple undirected graphs and some simple graphical transformations. The independence statements derivable in this system are equivalent to those obtainable by the graphoid axioms. Therefore, this is a purely graphical proof technique for conditional independence.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:17 GMT" } ]
1,364,256,000,000
[ [ "Shachter", "Ross D.", "" ] ]
1303.5750
Prakash P. Shenoy
Prakash P. Shenoy
A Fusion Algorithm for Solving Bayesian Decision Problems
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-361-369
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper proposes a new method for solving Bayesian decision problems. The method consists of representing a Bayesian decision problem as a valuation-based system and applying a fusion algorithm for solving it. The fusion algorithm is a hybrid of local computational methods for computation of marginals of joint probability distributions and the local computational methods for discrete optimization problems.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:23 GMT" } ]
1,364,256,000,000
[ [ "Shenoy", "Prakash P.", "" ] ]
1303.5751
Solomon Eyal Shimony
Solomon Eyal Shimony
Algorithms for Irrelevance-Based Partial MAPs
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-370-377
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Irrelevance-based partial MAPs are useful constructs for domain-independent explanation using belief networks. We look at two definitions for such partial MAPs, and prove important properties that are useful in designing algorithms for computing them effectively. We make use of these properties in modifying our standard MAP best-first algorithm, so as to handle irrelevance-based partial MAPs.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:28 GMT" } ]
1,364,256,000,000
[ [ "Shimony", "Solomon Eyal", "" ] ]
1303.5752
Philippe Smets
Philippe Smets
About Updating
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-378-385
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Survey of several forms of updating, with a practical illustrative example. We study several updating (conditioning) schemes that emerge naturally from a common scenarion to provide some insights into their meaning. Updating is a subtle operation and there is no single method, no single 'good' rule. The choice of the appropriate rule must always be given due consideration. Planchet (1989) presents a mathematical survey of many rules. We focus on the practical meaning of these rules. After summarizing the several rules for conditioning, we present an illustrative example in which the various forms of conditioning can be explained.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:33 GMT" } ]
1,364,256,000,000
[ [ "Smets", "Philippe", "" ] ]
1303.5753
Paul Snow
Paul Snow
Compressed Constraints in Probabilistic Logic and Their Revision
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-386-391
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In probabilistic logic entailments, even moderate size problems can yield linear constraint systems with so many variables that exact methods are impractical. This difficulty can be remedied in many cases of interest by introducing a three valued logic (true, false, and "don't care"). The three-valued approach allows the construction of "compressed" constraint systems which have the same solution sets as their two-valued counterparts, but which may involve dramatically fewer variables. Techniques to calculate point estimates for the posterior probabilities of entailed sentences are discussed.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:38 GMT" } ]
1,364,256,000,000
[ [ "Snow", "Paul", "" ] ]
1303.5754
Peter L. Spirtes
Peter L. Spirtes
Detecting Causal Relations in the Presence of Unmeasured Variables
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-392-397
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The presence of latent variables can greatly complicate inferences about causal relations between measured variables from statistical data. In many cases, the presence of latent variables makes it impossible to determine for two measured variables A and B, whether A causes B, B causes A, or there is some common cause. In this paper I present several theorems that state conditions under which it is possible to reliably infer the causal relation between two measured variables, regardless of whether latent variables are acting or not.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:43 GMT" } ]
1,364,256,000,000
[ [ "Spirtes", "Peter L.", "" ] ]
1303.5755
Deborah L. Thurston
Deborah L. Thurston, Yun Qi Tian
A Method for Integrating Utility Analysis into an Expert System for Design Evaluation
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-398-405
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In mechanical design, there is often unavoidable uncertainty in estimates of design performance. Evaluation of design alternatives requires consideration of the impact of this uncertainty. Expert heuristics embody assumptions regarding the designer's attitude towards risk and uncertainty that might be reasonable in most cases but inaccurate in others. We present a technique to allow designers to incorporate their own unique attitude towards uncertainty as opposed to those assumed by the domain expert's rules. The general approach is to eliminate aspects of heuristic rules which directly or indirectly include assumptions regarding the user's attitude towards risk, and replace them with explicit, user-specified probabilistic multi attribute utility and probability distribution functions. We illustrate the method in a system for material selection for automobile bumpers.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:48 GMT" } ]
1,364,256,000,000
[ [ "Thurston", "Deborah L.", "" ], [ "Tian", "Yun Qi", "" ] ]
1303.5756
Wilson X. Wen
Wilson X. Wen
From Relational Databases to Belief Networks
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-406-413
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The relationship between belief networks and relational databases is examined. Based on this analysis, a method to construct belief networks automatically from statistical relational data is proposed. A comparison between our method and other methods shows that our method has several advantages when generalization or prediction is deeded.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:53 GMT" } ]
1,364,256,000,000
[ [ "Wen", "Wilson X.", "" ] ]
1303.5757
Nic Wilson
Nic Wilson
A Monte-Carlo Algorithm for Dempster-Shafer Belief
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-414-417
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A very computationally-efficient Monte-Carlo algorithm for the calculation of Dempster-Shafer belief is described. If Bel is the combination using Dempster's Rule of belief functions Bel, ..., Bel,7, then, for subset b of the frame C), Bel(b) can be calculated in time linear in 1(31 and m (given that the weight of conflict is bounded). The algorithm can also be used to improve the complexity of the Shenoy-Shafer algorithms on Markov trees, and be generalised to calculate Dempster-Shafer Belief over other logics.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:33:58 GMT" } ]
1,364,256,000,000
[ [ "Wilson", "Nic", "" ] ]
1303.5758
Michael S. K. M. Wong
Michael S. K. M. Wong, Y. Y. Yao, P. Lingras
Compatibility of Quantitative and Qualitative Representations of Belief
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-418-424
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The compatibility of quantitative and qualitative representations of beliefs was studied extensively in probability theory. It is only recently that this important topic is considered in the context of belief functions. In this paper, the compatibility of various quantitative belief measures and qualitative belief structures is investigated. Four classes of belief measures considered are: the probability function, the monotonic belief function, Shafer's belief function, and Smets' generalized belief function. The analysis of their individual compatibility with different belief structures not only provides a sound b<msis for these quantitative measures, but also alleviates some of the difficulties in the acquisition and interpretation of numeric belief numbers. It is shown that the structure of qualitative probability is compatible with monotonic belief functions. Moreover, a belief structure slightly weaker than that of qualitative belief is compatible with Smets' generalized belief functions.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:34:02 GMT" } ]
1,364,256,000,000
[ [ "Wong", "Michael S. K. M.", "" ], [ "Yao", "Y. Y.", "" ], [ "Lingras", "P.", "" ] ]
1303.5759
Hong Xu
Hong Xu
An Efficient Implementation of Belief Function Propagation
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-425-432
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The local computation technique (Shafer et al. 1987, Shafer and Shenoy 1988, Shenoy and Shafer 1986) is used for propagating belief functions in so called a Markov Tree. In this paper, we describe an efficient implementation of belief function propagation on the basis of the local computation technique. The presented method avoids all the redundant computations in the propagation process, and so makes the computational complexity decrease with respect to other existing implementations (Hsia and Shenoy 1989, Zarley et al. 1988). We also give a combined algorithm for both propagation and re-propagation which makes the re-propagation process more efficient when one or more of the prior belief functions is changed.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:34:07 GMT" } ]
1,364,256,000,000
[ [ "Xu", "Hong", "" ] ]
1303.5760
Ronald R. Yager
Ronald R. Yager
A Non-Numeric Approach to Multi-Criteria/Multi-Expert Aggregation Based on Approximate Reasoning
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-433-437
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe a technique that can be used for the fusion of multiple sources of information as well as for the evaluation and selection of alternatives under multi-criteria. Three important properties contribute to the uniqueness of the technique introduced. The first is the ability to do all necessary operations and aggregations with information that is of a nonnumeric linguistic nature. This facility greatly reduces the burden on the providers of information, the experts. A second characterizing feature is the ability assign, again linguistically, differing importance to the criteria or in the case of information fusion to the individual sources of information. A third significant feature of the approach is its ability to be used as method to find a consensus of the opinion of multiple experts on the issue of concern. The techniques used in this approach are base on ideas developed from the theory of approximate reasoning. We illustrate the approach with a problem of project selection.
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:34:12 GMT" } ]
1,364,256,000,000
[ [ "Yager", "Ronald R.", "" ] ]
1303.5761
Henry E. Kyburg Jr.
Henry E. Kyburg Jr
Why Do We Need Foundations for Modelling Uncertainties?
Appears in Proceedings of the Seventh Conference on Uncertainty in Artificial Intelligence (UAI1991)
null
null
UAI-P-1991-PG-438-442
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Surely we want solid foundations. What kind of castle can we build on sand? What is the point of devoting effort to balconies and minarets, if the foundation may be so weak as to allow the structure to collapse of its own weight? We want our foundations set on bedrock, designed to last for generations. Who would want an architect who cannot certify the soundness of the foundations of his buildings?
[ { "version": "v1", "created": "Wed, 20 Mar 2013 15:34:17 GMT" } ]
1,364,256,000,000
[ [ "Kyburg", "Henry E.", "Jr" ] ]
1303.5929
Sourish Dasgupta
Sourish Dasgupta, Ankur Padia, Kushal Shah, Rupali KaPatel, Prasenjit Majumder
DLOLIS-A: Description Logic based Text Ontology Learning
11 pages
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Ontology Learning has been the subject of intensive study for the past decade. Researchers in this field have been motivated by the possibility of automatically building a knowledge base on top of text documents so as to support reasoning based knowledge extraction. While most works in this field have been primarily statistical (known as light-weight Ontology Learning) not much attempt has been made in axiomatic Ontology Learning (called heavy-weight Ontology Learning) from Natural Language text documents. Heavy-weight Ontology Learning supports more precise formal logic-based reasoning when compared to statistical ontology learning. In this paper we have proposed a sound Ontology Learning tool DLOL_(IS-A) that maps English language IS-A sentences into their equivalent Description Logic (DL) expressions in order to automatically generate a consistent pair of T-box and A-box thereby forming both regular (definitional form) and generalized (axiomatic form) DL ontology. The current scope of the paper is strictly limited to IS-A sentences that exclude the possible structures of: (i) implicative IS-A sentences, and (ii) "Wh" IS-A questions. Other linguistic nuances that arise out of pragmatics and epistemic of IS-A sentences are beyond the scope of this present work. We have adopted Gold Standard based Ontology Learning evaluation on chosen IS-A rich Wikipedia documents.
[ { "version": "v1", "created": "Sun, 24 Mar 2013 08:39:18 GMT" } ]
1,364,256,000,000
[ [ "Dasgupta", "Sourish", "" ], [ "Padia", "Ankur", "" ], [ "Shah", "Kushal", "" ], [ "KaPatel", "Rupali", "" ], [ "Majumder", "Prasenjit", "" ] ]
1303.6932
Saleem Abdullah
Muhammad Aslam, Saleem Abdullah and Kifayat ullah
Bipolar Fuzzy Soft sets and its applications in decision making problem
null
null
10.3233/IFS-131031
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article, we combine the concept of a bipolar fuzzy set and a soft set. We introduce the notion of bipolar fuzzy soft set and study fundamental properties. We study basic operations on bipolar fuzzy soft set. We define exdended union, intersection of two bipolar fuzzy soft set. We also give an application of bipolar fuzzy soft set into decision making problem. We give a general algorithm to solve decision making problems by using bipolar fuzzy soft set.
[ { "version": "v1", "created": "Sat, 23 Mar 2013 19:26:43 GMT" } ]
1,394,409,600,000
[ [ "Aslam", "Muhammad", "" ], [ "Abdullah", "Saleem", "" ], [ "ullah", "Kifayat", "" ] ]
1303.7137
Maksims Fiosins
A. Andronov and M. Fioshin
Discrete Optimization of Statistical Sample Sizes in Simulation by Using the Hierarchical Bootstrap Method
9 pages
proceedings of the 6th Tartu Conference, 1999
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Bootstrap method application in simulation supposes that value of random variables are not generated during the simulation process but extracted from available sample populations. In the case of Hierarchical Bootstrap the function of interest is calculated recurrently using the calculation tree. In the present paper we consider the optimization of sample sizes in each vertex of the calculation tree. The dynamic programming method is used for this aim. Proposed method allows to decrease a variance of system characteristic estimators.
[ { "version": "v1", "created": "Thu, 28 Mar 2013 14:48:44 GMT" } ]
1,364,515,200,000
[ [ "Andronov", "A.", "" ], [ "Fioshin", "M.", "" ] ]
1303.7201
Chrisantha Fernando Dr
Chrisantha Fernando, Vera Vasas
Design for a Darwinian Brain: Part 2. Cognitive Architecture
Submitted as Part 2 to Living Machines 2013, Natural History Museum, London. Code available on github as it is being developed to implement the cognitive architecture above, here... https://github.com/ctf20/DarwinianNeurodynamics
null
null
null
cs.AI
http://creativecommons.org/licenses/by-nc-sa/3.0/
The accumulation of adaptations in an open-ended manner during lifetime learning is a holy grail in reinforcement learning, intrinsic motivation, artificial curiosity, and developmental robotics. We present a specification for a cognitive architecture that is capable of specifying an unlimited range of behaviors. We then give examples of how it can stochastically explore an interesting space of adjacent possible behaviors. There are two main novelties; the first is a proper definition of the fitness of self-generated games such that interesting games are expected to evolve. The second is a modular and evolvable behavior language that has systematicity, productivity, and compositionality, i.e. it is a physical symbol system. A part of the architecture has already been implemented on a humanoid robot.
[ { "version": "v1", "created": "Thu, 28 Mar 2013 18:47:32 GMT" } ]
1,364,515,200,000
[ [ "Fernando", "Chrisantha", "" ], [ "Vasas", "Vera", "" ] ]
1304.0145
Soumya Kambhampati
Soumya C. Kambhampati, Thomas Liu
Phase Transition and Network Structure in Realistic SAT Problems
null
Published as student abstract in Proceedings of AAAI 2013 (National Conference on Artificial Intelligence)
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A fundamental question in Computer Science is understanding when a specific class of problems go from being computationally easy to hard. Because of its generality and applications, the problem of Boolean Satisfiability (aka SAT) is often used as a vehicle for investigating this question. A signal result from these studies is that the hardness of SAT problems exhibits a dramatic easy-to-hard phase transition with respect to the problem constrainedness. Past studies have however focused mostly on SAT instances generated using uniform random distributions, where all constraints are independently generated, and the problem variables are all considered of equal importance. These assumptions are unfortunately not satisfied by most real problems. Our project aims for a deeper understanding of hardness of SAT problems that arise in practice. We study two key questions: (i) How does easy-to-hard transition change with more realistic distributions that capture neighborhood sensitivity and rich-get-richer aspects of real problems and (ii) Can these changes be explained in terms of the network properties (such as node centrality and small-worldness) of the clausal networks of the SAT problems. Our results, based on extensive empirical studies and network analyses, provide important structural and computational insights into realistic SAT problems. Our extensive empirical studies show that SAT instances from realistic distributions do exhibit phase transition, but the transition occurs sooner (at lower values of constrainedness) than the instances from uniform random distribution. We show that this behavior can be explained in terms of their clausal network properties such as eigenvector centrality and small-worldness (measured indirectly in terms of the clustering coefficients and average node distance).
[ { "version": "v1", "created": "Sat, 30 Mar 2013 23:21:56 GMT" } ]
1,364,860,800,000
[ [ "Kambhampati", "Soumya C.", "" ], [ "Liu", "Thomas", "" ] ]
1304.0620
A. Anonymous
Heng Zhang, Yan Zhang
Disjunctive Logic Programs versus Normal Logic Programs
null
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper focuses on the expressive power of disjunctive and normal logic programs under the stable model semantics over finite, infinite, or arbitrary structures. A translation from disjunctive logic programs into normal logic programs is proposed and then proved to be sound over infinite structures. The equivalence of expressive power of two kinds of logic programs over arbitrary structures is shown to coincide with that over finite structures, and coincide with whether or not NP is closed under complement. Over finite structures, the intranslatability from disjunctive logic programs to normal logic programs is also proved if arities of auxiliary predicates and functions are bounded in a certain way.
[ { "version": "v1", "created": "Tue, 2 Apr 2013 12:59:41 GMT" } ]
1,364,947,200,000
[ [ "Zhang", "Heng", "" ], [ "Zhang", "Yan", "" ] ]
1304.0806
Faruk Karaaslan
Faruk Karaaslan, Naim Cagman, Saban Yilmaz
IFP-Intuitionistic fuzzy soft set theory and its applications
This paper has been withdrawn by the author due to a crucial errors in the notation and some problems in the algorithm
null
null
null
cs.AI
http://creativecommons.org/licenses/by/3.0/
In this work, we present definition of intuitionistic fuzzy parameterized (IFP) intuitionistic fuzzy soft set and its operations. Then we define IFP-aggregation operator to form IFP-intuitionistic fuzzy soft-decision-making method which allows constructing more efficient decision processes.
[ { "version": "v1", "created": "Tue, 2 Apr 2013 22:10:00 GMT" }, { "version": "v2", "created": "Fri, 18 Mar 2016 08:12:43 GMT" }, { "version": "v3", "created": "Sun, 17 Apr 2016 19:56:30 GMT" } ]
1,461,024,000,000
[ [ "Karaaslan", "Faruk", "" ], [ "Cagman", "Naim", "" ], [ "Yilmaz", "Saban", "" ] ]
1304.0897
Martin Suda
Martin Suda
Duality in STRIPS planning
6 pages (two columns), 4 tables
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe a duality mapping between STRIPS planning tasks. By exchanging the initial and goal conditions, taking their respective complements, and swapping for every action its precondition and delete list, one obtains for every STRIPS task its dual version, which has a solution if and only if the original does. This is proved by showing that the described transformation essentially turns progression (forward search) into regression (backward search) and vice versa. The duality sheds new light on STRIPS planning by allowing a transfer of ideas from one search approach to the other. It can be used to construct new algorithms from old ones, or (equivalently) to obtain new benchmarks from existing ones. Experiments show that the dual versions of IPC benchmarks are in general quite difficult for modern planners. This may be seen as a new challenge. On the other hand, the cases where the dual versions are easier to solve demonstrate that the duality can also be made useful in practice.
[ { "version": "v1", "created": "Wed, 3 Apr 2013 10:08:56 GMT" } ]
1,365,033,600,000
[ [ "Suda", "Martin", "" ] ]
1304.1081
Michael P. Wellman
Michael P. Wellman
Exploiting Functional Dependencies in Qualitative Probabilistic Reasoning
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-2-9
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Functional dependencies restrict the potential interactions among variables connected in a probabilistic network. This restriction can be exploited in qualitative probabilistic reasoning by introducing deterministic variables and modifying the inference rules to produce stronger conclusions in the presence of functional relations. I describe how to accomplish these modifications in qualitative probabilistic networks by exhibiting the update procedures for graphical transformations involving probabilistic and deterministic variables and combinations. A simple example demonstrates that the augmented scheme can reduce qualitative ambiguity that would arise without the special treatment of functional dependency. Analysis of qualitative synergy reveals that new higher-order relations are required to reason effectively about synergistic interactions among deterministic variables.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:54:31 GMT" } ]
1,365,120,000,000
[ [ "Wellman", "Michael P.", "" ] ]
1304.1082
Max Henrion
Max Henrion, Marek J. Druzdzel
Qualitative Propagation and Scenario-based Explanation of Probabilistic Reasoning
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-10-20
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Comprehensible explanations of probabilistic reasoning are a prerequisite for wider acceptance of Bayesian methods in expert systems and decision support systems. A study of human reasoning under uncertainty suggests two different strategies for explaining probabilistic reasoning: The first, qualitative belief propagation, traces the qualitative effect of evidence through a belief network from one variable to the next. This propagation algorithm is an alternative to the graph reduction algorithms of Wellman (1988) for inference in qualitative probabilistic networks. It is based on a qualitative analysis of intercausal reasoning, which is a generalization of Pearl's "explaining away", and an alternative to Wellman's definition of qualitative synergy. The other, Scenario-based reasoning, involves the generation of alternative causal "stories" accounting for the evidence. Comparing a few of the most probable scenarios provides an approximate way to explain the results of probabilistic reasoning. Both schemes employ causal as well as probabilistic knowledge. Probabilities may be presented as phrases and/or numbers. Users can control the style, abstraction and completeness of explanations.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:54:37 GMT" } ]
1,365,120,000,000
[ [ "Henrion", "Max", "" ], [ "Druzdzel", "Marek J.", "" ] ]
1304.1083
Thomas R. Shultz
Thomas R. Shultz
Managing Uncertainty in Rule Based Cognitive Models
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (1990) (pp. 21-26)
null
UAI-P-1990-PG-21-26
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An experiment replicated and extended recent findings on psychologically realistic ways of modeling propagation of uncertainty in rule based reasoning. Within a single production rule, the antecedent evidence can be summarized by taking the maximum of disjunctively connected antecedents and the minimum of conjunctively connected antecedents. The maximum certainty factor attached to each of the rule's conclusions can be sealed down by multiplication with this summarized antecedent certainty. Heckerman's modified certainty factor technique can be used to combine certainties for common conclusions across production rules.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:54:42 GMT" } ]
1,625,184,000,000
[ [ "Shultz", "Thomas R.", "" ] ]
1304.1084
Yizong Cheng
Yizong Cheng
Context-Dependent Similarity
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-27-31
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Attribute weighting and differential weighting, two major mechanisms for computing context-dependent similarity or dissimilarity measures are studied and compared. A dissimilarity measure based on subset size in the context is proposed and its metrization and application are given. It is also shown that while all attribute weighting dissimilarity measures are metrics differential weighting dissimilarity measures are usually non-metric.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:54:46 GMT" } ]
1,365,120,000,000
[ [ "Cheng", "Yizong", "" ] ]
1304.1085
David Heckerman
David Heckerman
Similarity Networks for the Construction of Multiple-Faults Belief Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-32-39
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A similarity network is a tool for constructing belief networks for the diagnosis of a single fault. In this paper, we examine modifications to the similarity-network representation that facilitate the construction of belief networks for the diagnosis of multiple coexisting faults.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:54:52 GMT" }, { "version": "v2", "created": "Sat, 16 May 2015 23:57:34 GMT" } ]
1,431,993,600,000
[ [ "Heckerman", "David", "" ] ]
1304.1086
Dekang Lin
Dekang Lin, Randy Goebel
Integrating Probabilistic, Taxonomic and Causal Knowledge in Abductive Diagnosis
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-40-45
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an abductive diagnosis theory that integrates probabilistic, causal and taxonomic knowledge. Probabilistic knowledge allows us to select the most likely explanation; causal knowledge allows us to make reasonable independence assumptions; taxonomic knowledge allows causation to be modeled at different levels of detail, and allows observations be described in different levels of precision. Unlike most other approaches where a causal explanation is a hypothesis that one or more causative events occurred, we define an explanation of a set of observations to be an occurrence of a chain of causation events. These causation events constitute a scenario where all the observations are true. We show that the probabilities of the scenarios can be computed from the conditional probabilities of the causation events. Abductive reasoning is inherently complex even if only modest expressive power is allowed. However, our abduction algorithm is exponential only in the number of observations to be explained, and is polynomial in the size of the knowledge base. This contrasts with many other abduction procedures that are exponential in the size of the knowledge base.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:54:58 GMT" } ]
1,365,120,000,000
[ [ "Lin", "Dekang", "" ], [ "Goebel", "Randy", "" ] ]
1304.1087
David L Poole
David L. Poole, Gregory M. Provan
What is an Optimal Diagnosis?
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-46-53
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Within diagnostic reasoning there have been a number of proposed definitions of a diagnosis, and thus of the most likely diagnosis, including most probable posterior hypothesis, most probable interpretation, most probable covering hypothesis, etc. Most of these approaches assume that the most likely diagnosis must be computed, and that a definition of what should be computed can be made a priori, independent of what the diagnosis is used for. We argue that the diagnostic problem, as currently posed, is incomplete: it does not consider how the diagnosis is to be used, or the utility associated with the treatment of the abnormalities. In this paper we analyze several well-known definitions of diagnosis, showing that the different definitions of the most likely diagnosis have different qualitative meanings, even given the same input data. We argue that the most appropriate definition of (optimal) diagnosis needs to take into account the utility of outcomes and what the diagnosis is used for.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:03 GMT" } ]
1,365,120,000,000
[ [ "Poole", "David L.", "" ], [ "Provan", "Gregory M.", "" ] ]
1304.1088
Edward H. Herskovits
Edward H. Herskovits, Gregory F. Cooper
Kutato: An Entropy-Driven System for Construction of Probabilistic Expert Systems from Databases
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-54-63
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Kutato is a system that takes as input a database of cases and produces a belief network that captures many of the dependence relations represented by those data. This system incorporates a module for determining the entropy of a belief network and a module for constructing belief networks based on entropy calculations. Kutato constructs an initial belief network in which all variables in the database are assumed to be marginally independent. The entropy of this belief network is calculated, and that arc is added that minimizes the entropy of the resulting belief network. Conditional probabilities for an arc are obtained directly from the database. This process continues until an entropy-based threshold is reached. We have tested the system by generating databases from networks using the probabilistic logic-sampling method, and then using those databases as input to Kutato. The system consistently reproduces the original belief networks with high fidelity.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:08 GMT" } ]
1,365,120,000,000
[ [ "Herskovits", "Edward H.", "" ], [ "Cooper", "Gregory F.", "" ] ]
1304.1089
John S. Breese
John S. Breese, Eric J. Horvitz
Ideal Reformulation of Belief Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-64-72
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The intelligent reformulation or restructuring of a belief network can greatly increase the efficiency of inference. However, time expended for reformulation is not available for performing inference. Thus, under time pressure, there is a tradeoff between the time dedicated to reformulating the network and the time applied to the implementation of a solution. We investigate this partition of resources into time applied to reformulation and time used for inference. We shall describe first general principles for computing the ideal partition of resources under uncertainty. These principles have applicability to a wide variety of problems that can be divided into interdependent phases of problem solving. After, we shall present results of our empirical study of the problem of determining the ideal amount of time to devote to searching for clusters in belief networks. In this work, we acquired and made use of probability distributions that characterize (1) the performance of alternative heuristic search methods for reformulating a network instance into a set of cliques, and (2) the time for executing inference procedures on various belief networks. Given a preference model describing the value of a solution as a function of the delay required for its computation, the system selects an ideal time to devote to reformulation.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:14 GMT" } ]
1,365,120,000,000
[ [ "Breese", "John S.", "" ], [ "Horvitz", "Eric J.", "" ] ]
1304.1090
David Einav
David Einav, Michael R. Fehling
Computationally-Optimal Real-Resource Strategies
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-73-81
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper focuses on managing the cost of deliberation before action. In many problems, the overall quality of the solution reflects costs incurred and resources consumed in deliberation as well as the cost and benefit of execution, when both the resource consumption in deliberation phase, and the costs in deliberation and execution are uncertain and may be described by probability distribution functions. A feasible (in terms of resource consumption) strategy that minimizes the expected total cost is termed computationally-optimal. For a situation with several independent, uninterruptible methods to solve the problem, we develop a pseudopolynomial-time algorithm to construct generate-and-test computationally optimal strategy. We show this strategy-construction problem to be NP-complete, and apply Bellman's Optimality Principle to solve it efficiently.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:20 GMT" } ]
1,365,120,000,000
[ [ "Einav", "David", "" ], [ "Fehling", "Michael R.", "" ] ]
1304.1091
David Heckerman
David Heckerman, Eric J. Horvitz
Problem Formulation as the Reduction of a Decision Model
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-82-89
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we extend the QMRDT probabilistic model for the domain of internal medicine to include decisions about treatments. In addition, we describe how we can use the comprehensive decision model to construct a simpler decision model for a specific patient. In so doing, we transform the task of problem formulation to that of narrowing of a larger problem.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:26 GMT" }, { "version": "v2", "created": "Sat, 16 May 2015 23:53:50 GMT" } ]
1,431,993,600,000
[ [ "Heckerman", "David", "" ], [ "Horvitz", "Eric J.", "" ] ]
1304.1092
Robert P. Goldman
Robert P. Goldman, Eugene Charniak
Dynamic Construction of Belief Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-90-97
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe a method for incrementally constructing belief networks. We have developed a network-construction language similar to a forward-chaining language using data dependencies, but with additional features for specifying distributions. Using this language, we can define parameterized classes of probabilistic models. These parameterized models make it possible to apply probabilistic reasoning to problems for which it is impractical to have a single large static model.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:31 GMT" } ]
1,365,120,000,000
[ [ "Goldman", "Robert P.", "" ], [ "Charniak", "Eugene", "" ] ]
1304.1093
Solomon Eyal Shimony
Solomon Eyal Shimony, Eugene Charniak
A New Algorithm for Finding MAP Assignments to Belief Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-98-105
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new algorithm for finding maximum a-posterior) (MAP) assignments of values to belief networks. The belief network is compiled into a network consisting only of nodes with boolean (i.e. only 0 or 1) conditional probabilities. The MAP assignment is then found using a best-first search on the resulting network. We argue that, as one would anticipate, the algorithm is exponential for the general case, but only linear in the size of the network for poly trees.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:36 GMT" } ]
1,365,120,000,000
[ [ "Shimony", "Solomon Eyal", "" ], [ "Charniak", "Eugene", "" ] ]
1304.1094
K. Bayse
K. Bayse, M. Lejter, Keiji Kanazawa
Reducing Uncertainty in Navigation and Exploration
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-106-113
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A significant problem in designing mobile robot control systems involves coping with the uncertainty that arises in moving about in an unknown or partially unknown environment and relying on noisy or ambiguous sensor data to acquire knowledge about that environment. We describe a control system that chooses what activity to engage in next on the basis of expectations about how the information re- turned as a result of a given activity will improve 2 its knowledge about the spatial layout of its environment. Certain of the higher-level components of the control system are specified in terms of probabilistic decision models whose output is used to mediate the behavior of lower-level control components responsible for movement and sensing.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:42 GMT" } ]
1,365,120,000,000
[ [ "Bayse", "K.", "" ], [ "Lejter", "M.", "" ], [ "Kanazawa", "Keiji", "" ] ]
1304.1095
Ingo Beinlich
Ingo Beinlich, Edward H. Herskovits
Ergo: A Graphical Environment for Constructing Bayesian
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-114-121
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We describe an environment that considerably simplifies the process of generating Bayesian belief networks. The system has been implemented on readily available, inexpensive hardware, and provides clarity and high performance. We present an introduction to Bayesian belief networks, discuss algorithms for inference with these networks, and delineate the classes of problems that can be solved with this paradigm. We then describe the hardware and software that constitute the system, and illustrate Ergo's use with several example
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:48 GMT" } ]
1,365,120,000,000
[ [ "Beinlich", "Ingo", "" ], [ "Herskovits", "Edward H.", "" ] ]
1304.1096
John S. Breese
John S. Breese, Kenneth W. Fertig
Decision Making with Interval Influence Diagrams
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-122-129
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In previous work (Fertig and Breese, 1989; Fertig and Breese, 1990) we defined a mechanism for performing probabilistic reasoning in influence diagrams using interval rather than point-valued probabilities. In this paper we extend these procedures to incorporate decision nodes and interval-valued value functions in the diagram. We derive the procedures for chance node removal (calculating expected value) and decision node removal (optimization) in influence diagrams where lower bounds on probabilities are stored at each chance node and interval bounds are stored on the value function associated with the diagram's value node. The output of the algorithm are a set of admissible alternatives for each decision variable and a set of bounds on expected value based on the imprecision in the input. The procedure can be viewed as an approximation to a full e-dimensional sensitivity analysis where n are the number of imprecise probability distributions in the input. We show the transformations are optimal and sound. The performance of the algorithm on an influence diagrams is investigated and compared to an exact algorithm.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:54 GMT" } ]
1,365,120,000,000
[ [ "Breese", "John S.", "" ], [ "Fertig", "Kenneth W.", "" ] ]
1304.1097
R. Martin Chavez
R. Martin Chavez, Gregory F. Cooper
A Randomized Approximation Algorithm of Logic Sampling
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-130-135
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years, researchers in decision analysis and artificial intelligence (AI) have used Bayesian belief networks to build models of expert opinion. Using standard methods drawn from the theory of computational complexity, workers in the field have shown that the problem of exact probabilistic inference on belief networks almost certainly requires exponential computation in the worst ease [3]. We have previously described a randomized approximation scheme, called BN-RAS, for computation on belief networks [ 1, 2, 4]. We gave precise analytic bounds on the convergence of BN-RAS and showed how to trade running time for accuracy in the evaluation of posterior marginal probabilities. We now extend our previous results and demonstrate the generality of our framework by applying similar mathematical techniques to the analysis of convergence for logic sampling [7], an alternative simulation algorithm for probabilistic inference.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:55:59 GMT" } ]
1,365,120,000,000
[ [ "Chavez", "R. Martin", "" ], [ "Cooper", "Gregory F.", "" ] ]
1304.1099
Peter Haddawy
Peter Haddawy
Time, Chance, and Action
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-147-154
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
To operate intelligently in the world, an agent must reason about its actions. The consequences of an action are a function of both the state of the world and the action itself. Many aspects of the world are inherently stochastic, so a representation for reasoning about actions must be able to express chances of world states as well as indeterminacy in the effects of actions and other events. This paper presents a propositional temporal probability logic for representing and reasoning about actions. The logic can represent the probability that facts hold and events occur at various times. It can represent the probability that actions and other events affect the future. It can represent concurrent actions and conditions that hold or change during execution of an action. The model of probability relates probabilities over time. The logical language integrates both modal and probabilistic constructs and can thus represent and distinguish between possibility, probability, and truth. Several examples illustrating the use of the logic are given.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:11 GMT" } ]
1,365,120,000,000
[ [ "Haddawy", "Peter", "" ] ]
1304.1100
Michael C. Horsch
Michael C. Horsch, David L. Poole
A Dynamic Approach to Probabilistic Inference
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-155-161
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we present a framework for dynamically constructing Bayesian networks. We introduce the notion of a background knowledge base of schemata, which is a collection of parameterized conditional probability statements. These schemata explicitly separate the general knowledge of properties an individual may have from the specific knowledge of particular individuals that may have these properties. Knowledge of individuals can be combined with this background knowledge to create Bayesian networks, which can then be used in any propagation scheme. We discuss the theory and assumptions necessary for the implementation of dynamic Bayesian networks, and indicate where our approach may be useful.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:17 GMT" } ]
1,365,120,000,000
[ [ "Horsch", "Michael C.", "" ], [ "Poole", "David L.", "" ] ]
1304.1101
Frank Jensen
Frank Jensen, S. K. Anderson
Approximations in Bayesian Belief Universe for Knowledge Based Systems
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-162-169
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
When expert systems based on causal probabilistic networks (CPNs) reach a certain size and complexity, the "combinatorial explosion monster" tends to be present. We propose an approximation scheme that identifies rarely occurring cases and excludes these from being processed as ordinary cases in a CPN-based expert system. Depending on the topology and the probability distributions of the CPN, the numbers (representing probabilities of state combinations) in the underlying numerical representation can become very small. Annihilating these numbers and utilizing the resulting sparseness through data structuring techniques often results in several orders of magnitude of improvement in the consumption of computer resources. Bounds on the errors introduced into a CPN-based expert system through approximations are established. Finally, reports on empirical studies of applying the approximation scheme to a real-world CPN are given.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:23 GMT" } ]
1,365,120,000,000
[ [ "Jensen", "Frank", "" ], [ "Anderson", "S. K.", "" ] ]
1304.1102
Paul E. Lehner
Paul E. Lehner
Robust Inference Policies
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-170-179
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A series of monte carlo studies were performed to assess the extent to which different inference procedures robustly output reasonable belief values in the context of increasing levels of judgmental imprecision. It was found that, when compared to an equal-weights linear model, the Bayesian procedures are more likely to deduce strong support for a hypothesis. But, the Bayesian procedures are also more likely to strongly support the wrong hypothesis. Bayesian techniques are more powerful, but are also more error prone.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:28 GMT" } ]
1,365,120,000,000
[ [ "Lehner", "Paul E.", "" ] ]
1304.1103
L. Liu
L. Liu, Y. Ma, D. Wilkins, Z. Bian, X. Ying
Minimum Error Tree Decomposition
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-180-185
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper describes a generalization of previous methods for constructing tree-structured belief network with hidden variables. The major new feature of the described method is the ability to produce a tree decomposition even when there are errors in the correlation data among the input variables. This is an important extension of existing methods since the correlational coefficients usually cannot be measured with precision. The technique involves using a greedy search algorithm that locally minimizes an error function.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:34 GMT" } ]
1,365,120,000,000
[ [ "Liu", "L.", "" ], [ "Ma", "Y.", "" ], [ "Wilkins", "D.", "" ], [ "Bian", "Z.", "" ], [ "Ying", "X.", "" ] ]
1304.1104
J. W. Miller
J. W. Miller, R. M. Goodman
A Polynomial Time Algorithm for Finding Bayesian Probabilities from Marginal Constraints
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-186-193
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A method of calculating probability values from a system of marginal constraints is presented. Previous systems for finding the probability of a single attribute have either made an independence assumption concerning the evidence or have required, in the worst case, time exponential in the number of attributes of the system. In this paper a closed form solution to the probability of an attribute given the evidence is found. The closed form solution, however does not enforce the (non-linear) constraint that all terms in the underlying distribution be positive. The equation requires O(r^3) steps to evaluate, where r is the number of independent marginal constraints describing the system at the time of evaluation. Furthermore, a marginal constraint may be exchanged with a new constraint, and a new solution calculated in O(r^2) steps. This method is appropriate for calculating probabilities in a real time expert system
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:39 GMT" } ]
1,365,120,000,000
[ [ "Miller", "J. W.", "" ], [ "Goodman", "R. M.", "" ] ]
1304.1105
Richard E. Neapolitan
Richard E. Neapolitan, James Kenevan
Computation of Variances in Causal Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-194-203
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The causal (belief) network is a well-known graphical structure for representing independencies in a joint probability distribution. The exact methods and the approximation methods, which perform probabilistic inference in causal networks, often treat the conditional probabilities which are stored in the network as certain values. However, if one takes either a subjectivistic or a limiting frequency approach to probability, one can never be certain of probability values. An algorithm for probabilistic inference should not only be capable of reporting the inferred probabilities; it should also be capable of reporting the uncertainty in these probabilities relative to the uncertainty in the probabilities which are stored in the network. In section 2 of this paper a method is given for determining the prior variances of the probabilities of all the nodes. Section 3 contains an approximation method for determining the variances in inferred probabilities.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:45 GMT" } ]
1,365,120,000,000
[ [ "Neapolitan", "Richard E.", "" ], [ "Kenevan", "James", "" ] ]
1304.1106
Keung-Chi Ng
Keung-Chi Ng, Bruce Abramson
A Sensitivity Analysis of Pathfinder
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-204-211
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Knowledge elicitation is one of the major bottlenecks in expert system design. Systems based on Bayes nets require two types of information--network structure and parameters (or probabilities). Both must be elicited from the domain expert. In general, parameters have greater opacity than structure, and more time is spent in their refinement than in any other phase of elicitation. Thus, it is important to determine the point of diminishing returns, beyond which further refinements will promise little (if any) improvement. Sensitivity analyses address precisely this issue--the sensitivity of a model to the precision of its parameters. In this paper, we report the results of a sensitivity analysis of Pathfinder, a Bayes net based system for diagnosing pathologies of the lymph system. This analysis is intended to shed some light on the relative importance of structure and parameters to system performance, as well as the sensitivity of a system based on a Bayes net to noise in its assessed parameters.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:51 GMT" } ]
1,365,120,000,000
[ [ "Ng", "Keung-Chi", "" ], [ "Abramson", "Bruce", "" ] ]
1304.1107
Sampath Srinivas
Sampath Srinivas, John S. Breese
IDEAL: A Software Package for Analysis of Influence Diagrams
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-212-219
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
IDEAL (Influence Diagram Evaluation and Analysis in Lisp) is a software environment for creation and evaluation of belief networks and influence diagrams. IDEAL is primarily a research tool and provides an implementation of many of the latest developments in belief network and influence diagram evaluation in a unified framework. This paper describes IDEAL and some lessons learned during its development.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:56:56 GMT" } ]
1,365,120,000,000
[ [ "Srinivas", "Sampath", "" ], [ "Breese", "John S.", "" ] ]
1304.1108
Tom S. Verma
Tom S. Verma, Judea Pearl
On the Equivalence of Causal Models
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-220-227
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Scientists often use directed acyclic graphs (days) to model the qualitative structure of causal theories, allowing the parameters to be estimated from observational data. Two causal models are equivalent if there is no experiment which could distinguish one from the other. A canonical representation for causal models is presented which yields an efficient graphical criterion for deciding equivalence, and provides a theoretical basis for extracting causal structures from empirical data. This representation is then extended to the more general case of an embedded causal model, that is, a dag in which only a subset of the variables are observable. The canonical representation presented here yields an efficient algorithm for determining when two embedded causal models reflect the same dependency information. This algorithm leads to a model theoretic definition of causation in terms of statistical dependencies.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:02 GMT" } ]
1,365,120,000,000
[ [ "Verma", "Tom S.", "" ], [ "Pearl", "Judea", "" ] ]
1304.1109
Lambert E. Wixson
Lambert E. Wixson
Application of Confidence Intervals to the Autonomous Acquisition of High-level Spatial Knowledge
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-228-236
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Objects in the world usually appear in context, participating in spatial relationships and interactions that are predictable and expected. Knowledge of these contexts can be used in the task of using a mobile camera to search for a specified object in a room. We call this the object search task. This paper is concerned with representing this knowledge in a manner facilitating its application to object search while at the same time lending itself to autonomous learning by a robot. The ability for the robot to learn such knowledge without supervision is crucial due to the vast number of possible relationships that can exist for any given set of objects. Moreover, since a robot will not have an infinite amount of time to learn, it must be able to determine an order in which to look for possible relationships so as to maximize the rate at which new knowledge is gained. In effect, there must be a "focus of interest" operator that allows the robot to choose which examples are likely to convey the most new information and should be examined first. This paper demonstrates how a representation based on statistical confidence intervals allows the construction of a system that achieves the above goals. An algorithm, based on the Highest Impact First heuristic, is presented as a means for providing a "focus of interest" with which to control the learning process, and examples are given.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:08 GMT" } ]
1,365,120,000,000
[ [ "Wixson", "Lambert E.", "" ] ]
1304.1110
Ross D. Shachter
Ross D. Shachter, Stig K. Andersen, Kim-Leng Poh
Directed Reduction Algorithms and Decomposable Graphs
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-237-244
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years, there have been intense research efforts to develop efficient methods for probabilistic inference in probabilistic influence diagrams or belief networks. Many people have concluded that the best methods are those based on undirected graph structures, and that those methods are inherently superior to those based on node reduction operations on the influence diagram. We show here that these two approaches are essentially the same, since they are explicitly or implicity building and operating on the same underlying graphical structures. In this paper we examine those graphical structures and show how this insight can lead to an improved class of directed reduction methods.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:14 GMT" } ]
1,365,120,000,000
[ [ "Shachter", "Ross D.", "" ], [ "Andersen", "Stig K.", "" ], [ "Poh", "Kim-Leng", "" ] ]
1304.1111
Wilson X. Wen
Wilson X. Wen
Optimal Decomposition of Belief Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-245-256
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, optimum decomposition of belief networks is discussed. Some methods of decomposition are examined and a new method - the method of Minimum Total Number of States (MTNS) - is proposed. The problem of optimum belief network decomposition under our framework, as under all the other frameworks, is shown to be NP-hard. According to the computational complexity analysis, an algorithm of belief network decomposition is proposed in (Wee, 1990a) based on simulated annealing.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:20 GMT" } ]
1,365,120,000,000
[ [ "Wen", "Wilson X.", "" ] ]
1304.1112
Michelle Baker
Michelle Baker, Terrance E. Boult
Pruning Bayesian Networks for Efficient Computation
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-257-264
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper analyzes the circumstances under which Bayesian networks can be pruned in order to reduce computational complexity without altering the computation for variables of interest. Given a problem instance which consists of a query and evidence for a set of nodes in the network, it is possible to delete portions of the network which do not participate in the computation for the query. Savings in computational complexity can be large when the original network is not singly connected. Results analogous to those described in this paper have been derived before [Geiger, Verma, and Pearl 89, Shachter 88] but the implications for reducing complexity of the computations in Bayesian networks have not been stated explicitly. We show how a preprocessing step can be used to prune a Bayesian network prior to using standard algorithms to solve a given problem instance. We also show how our results can be used in a parallel distributed implementation in order to achieve greater savings. We define a computationally equivalent subgraph of a Bayesian network. The algorithm developed in [Geiger, Verma, and Pearl 89] is modified to construct the subgraphs described in this paper with O(e) complexity, where e is the number of edges in the Bayesian network. Finally, we define a minimal computationally equivalent subgraph and prove that the subgraphs described are minimal.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:25 GMT" } ]
1,365,120,000,000
[ [ "Baker", "Michelle", "" ], [ "Boult", "Terrance E.", "" ] ]
1304.1113
Jonathan Stillman
Jonathan Stillman
On Heuristics for Finding Loop Cutsets in Multiply-Connected Belief Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-265-272
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a new heuristic algorithm for the problem of finding minimum size loop cutsets in multiply connected belief networks. We compare this algorithm to that proposed in [Suemmondt and Cooper, 1988]. We provide lower bounds on the performance of these algorithms with respect to one another and with respect to optimal. We demonstrate that no heuristic algorithm for this problem cam be guaranteed to produce loop cutsets within a constant difference from optimal. We discuss experimental results based on randomly generated networks, and discuss future work and open questions.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:31 GMT" } ]
1,365,120,000,000
[ [ "Stillman", "Jonathan", "" ] ]
1304.1114
Jaap Suermondt
Jaap Suermondt, Gregory F. Cooper, David Heckerman
A Combination of Cutset Conditioning with Clique-Tree Propagation in the Pathfinder System
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-273-280
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cutset conditioning and clique-tree propagation are two popular methods for performing exact probabilistic inference in Bayesian belief networks. Cutset conditioning is based on decomposition of a subset of network nodes, whereas clique-tree propagation depends on aggregation of nodes. We describe a means to combine cutset conditioning and clique- tree propagation in an approach called aggregation after decomposition (AD). We discuss the application of the AD method in the Pathfinder system, a medical expert system that offers assistance with diagnosis in hematopathology.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:38 GMT" } ]
1,365,120,000,000
[ [ "Suermondt", "Jaap", "" ], [ "Cooper", "Gregory F.", "" ], [ "Heckerman", "David", "" ] ]
1304.1115
Enrique H. Ruspini
Enrique H. Ruspini
Possibility as Similarity: the Semantics of Fuzzy Logic
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-281-289
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper addresses fundamental issues on the nature of the concepts and structures of fuzzy logic, focusing, in particular, on the conceptual and functional differences that exist between probabilistic and possibilistic approaches. A semantic model provides the basic framework to define possibilistic structures and concepts by means of a function that quantifies proximity, closeness, or resemblance between pairs of possible worlds. The resulting model is a natural extension, based on multiple conceivability relations, of the modal logic concepts of necessity and possibility. By contrast, chance-oriented probabilistic concepts and structures rely on measures of set extension that quantify the proportion of possible worlds where a proposition is true. Resemblance between possible worlds is quantified by a generalized similarity relation: a function that assigns a number between O and 1 to every pair of possible worlds. Using this similarity relation, which is a form of numerical complement of a classic metric or distance, it is possible to define and interpret the major constructs and methods of fuzzy logic: conditional and unconditioned possibility and necessity distributions and the generalized modus ponens of Zadeh.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:44 GMT" } ]
1,365,120,000,000
[ [ "Ruspini", "Enrique H.", "" ] ]
1304.1116
Soumitra Dutta
Soumitra Dutta, Piero P. Bonissone
Integrating Case-Based and Rule-Based Reasoning: the Possibilistic Connection
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-290-300
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Rule based reasoning (RBR) and case based reasoning (CBR) have emerged as two important and complementary reasoning methodologies in artificial intelligence (Al). For problem solving in complex, real world situations, it is useful to integrate RBR and CBR. This paper presents an approach to achieve a compact and seamless integration of RBR and CBR within the base architecture of rules. The paper focuses on the possibilistic nature of the approximate reasoning methodology common to both CBR and RBR. In CBR, the concept of similarity is casted as the complement of the distance between cases. In RBR the transitivity of similarity is the basis for the approximate deductions based on the generalized modus ponens. It is shown that the integration of CBR and RBR is possible without altering the inference engine of RBR. This integration is illustrated in the financial domain of mergers and acquisitions. These ideas have been implemented in a prototype system called MARS.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:49 GMT" } ]
1,365,120,000,000
[ [ "Dutta", "Soumitra", "" ], [ "Bonissone", "Piero P.", "" ] ]
1304.1117
Ronald R. Yager
Ronald R. Yager
Credibility Discounting in the Theory of Approximate Reasoning
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-301-306
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We are concerned with the problem of introducing credibility type information into reasoning systems. The concept of credibility allows us to discount information provided by agents. An important characteristic of this kind of procedure is that a complete lack of credibility rather than resulting in the negation of the information provided results in the nullification of the information provided. We suggest a representational scheme for credibility qualification in the theory of approximate reasoning. We discuss the concept of relative credibility. By this idea we mean to indicate situations in which the credibility of a piece of evidence is determined by its compatibility with higher priority evidence. This situation leads to structures very much in the spirit of nonmonotonic reasoning.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:57:54 GMT" } ]
1,365,120,000,000
[ [ "Yager", "Ronald R.", "" ] ]
1304.1118
Didier Dubois
Didier Dubois, Henri Prade
Updating with Belief Functions, Ordinal Conditioning Functions and Possibility Measures
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-307-316
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper discusses how a measure of uncertainty representing a state of knowledge can be updated when a new information, which may be pervaded with uncertainty, becomes available. This problem is considered in various framework, namely: Shafer's evidence theory, Zadeh's possibility theory, Spohn's theory of epistemic states. In the two first cases, analogues of Jeffrey's rule of conditioning are introduced and discussed. The relations between Spohn's model and possibility theory are emphasized and Spohn's updating rule is contrasted with the Jeffrey-like rule of conditioning in possibility theory. Recent results by Shenoy on the combination of ordinal conditional functions are reinterpreted in the language of possibility theory. It is shown that Shenoy's combination rule has a well-known possibilistic counterpart.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:00 GMT" } ]
1,365,120,000,000
[ [ "Dubois", "Didier", "" ], [ "Prade", "Henri", "" ] ]
1304.1120
Philippe Smets
Philippe Smets
The Transferable Belief Model and Other Interpretations of Dempster-Shafer's Model
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-326-333
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dempster-Shafer's model aims at quantifying degrees of belief But there are so many interpretations of Dempster-Shafer's theory in the literature that it seems useful to present the various contenders in order to clarify their respective positions. We shall successively consider the classical probability model, the upper and lower probabilities model, Dempster's model, the transferable belief model, the evidentiary value model, the provability or necessity model. None of these models has received the qualification of Dempster-Shafer. In fact the transferable belief model is our interpretation not of Dempster's work but of Shafer's work as presented in his book (Shafer 1976, Smets 1988). It is a ?purified' form of Dempster-Shafer's model in which any connection with probability concept has been deleted. Any model for belief has at least two components: one static that describes our state of belief, the other dynamic that explains how to update our belief given new pieces of information. We insist on the fact that both components must be considered in order to study these models. Too many authors restrict themselves to the static component and conclude that Dempster-Shafer theory is the same as some other theory. But once the dynamic component is considered, these conclusions break down. Any comparison based only on the static component is too restricted. The dynamic component must also be considered as the originality of the models based on belief functions lies in its dynamic component.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:12 GMT" } ]
1,365,120,000,000
[ [ "Smets", "Philippe", "" ] ]
1304.1121
Prakash P. Shenoy
Prakash P. Shenoy, Glenn Shafer
Valuation-Based Systems for Discrete Optimization
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-334-343
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper describes valuation-based systems for representing and solving discrete optimization problems. In valuation-based systems, we represent information in an optimization problem using variables, sample spaces of variables, a set of values, and functions that map sample spaces of sets of variables to the set of values. The functions, called valuations, represent the factors of an objective function. Solving the optimization problem involves using two operations called combination and marginalization. Combination tells us how to combine the factors of the joint objective function. Marginalization is either maximization or minimization. Solving an optimization problem can be simply described as finding the marginal of the joint objective function for the empty set. We state some simple axioms that combination and marginalization need to satisfy to enable us to solve an optimization problem using local computation. For optimization problems, the solution method of valuation-based systems reduces to non-serial dynamic programming. Thus our solution method for VBS can be regarded as an abstract description of dynamic programming. And our axioms can be viewed as conditions that permit the use of dynamic programming.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:17 GMT" } ]
1,365,120,000,000
[ [ "Shenoy", "Prakash P.", "" ], [ "Shafer", "Glenn", "" ] ]
1304.1122
Robert Kennes
Robert Kennes, Philippe Smets
Computational Aspects of the Mobius Transform
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-344-351
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we associate with every (directed) graph G a transformation called the Mobius transformation of the graph G. The Mobius transformation of the graph (O) is of major significance for Dempster-Shafer theory of evidence. However, because it is computationally very heavy, the Mobius transformation together with Dempster's rule of combination is a major obstacle to the use of Dempster-Shafer theory for handling uncertainty in expert systems. The major contribution of this paper is the discovery of the 'fast Mobius transformations' of (O). These 'fast Mobius transformations' are the fastest algorithms for computing the Mobius transformation of (O). As an easy but useful application, we provide, via the commonality function, an algorithm for computing Dempster's rule of combination which is much faster than the usual one.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:24 GMT" } ]
1,365,120,000,000
[ [ "Kennes", "Robert", "" ], [ "Smets", "Philippe", "" ] ]
1304.1123
Alessandro Saffiotti
Alessandro Saffiotti
Using Dempster-Shafer Theory in Knowledge Representation
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-352-361
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we suggest marrying Dempster-Shafer (DS) theory with Knowledge Representation (KR). Born out of this marriage is the definition of "Dempster-Shafer Belief Bases", abstract data types representing uncertain knowledge that use DS theory for representing strength of belief about our knowledge, and the linguistic structures of an arbitrary KR system for representing the knowledge itself. A formal result guarantees that both the properties of the given KR system and of DS theory are preserved. The general model is exemplified by defining DS Belief Bases where First Order Logic and (an extension of) KRYPTON are used as KR systems. The implementation problem is also touched upon.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:30 GMT" } ]
1,365,120,000,000
[ [ "Saffiotti", "Alessandro", "" ] ]
1304.1124
Hamid R. Berenji
Hamid R. Berenji, Yung-Yaw Chen, Chuen-Chien Lee, Jyh-Shing Jang, S. Murugesan
A Hierarchical Approach to Designing Approximate Reasoning-Based Controllers for Dynamic Physical Systems
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-362-369
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents a new technique for the design of approximate reasoning based controllers for dynamic physical systems with interacting goals. In this approach, goals are achieved based on a hierarchy defined by a control knowledge base and remain highly interactive during the execution of the control task. The approach has been implemented in a rule-based computer program which is used in conjunction with a prototype hardware system to solve the cart-pole balancing problem in real-time. It provides a complementary approach to the conventional analytical control methodology, and is of substantial use where a precise mathematical model of the process being controlled is not available.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:36 GMT" } ]
1,365,120,000,000
[ [ "Berenji", "Hamid R.", "" ], [ "Chen", "Yung-Yaw", "" ], [ "Lee", "Chuen-Chien", "" ], [ "Jang", "Jyh-Shing", "" ], [ "Murugesan", "S.", "" ] ]
1304.1125
L. W. Chang
L. W. Chang, Rangasami L. Kashyap
Evidence Combination and Reasoning and Its Application to Real-World Problem-Solving
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-370-377
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper a new mathematical procedure is presented for combining different pieces of evidence which are represented in the interval form to reflect our knowledge about the truth of a hypothesis. Evidences may be correlated to each other (dependent evidences) or conflicting in supports (conflicting evidences). First, assuming independent evidences, we propose a methodology to construct combination rules which obey a set of essential properties. The method is based on a geometric model. We compare results obtained from Dempster-Shafer's rule and the proposed combination rules with both conflicting and non-conflicting data and show that the values generated by proposed combining rules are in tune with our intuition in both cases. Secondly, in the case that evidences are known to be dependent, we consider extensions of the rules derived for handling conflicting evidence. The performance of proposed rules are shown by different examples. The results show that the proposed rules reasonably make decision under dependent evidences
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:42 GMT" } ]
1,365,120,000,000
[ [ "Chang", "L. W.", "" ], [ "Kashyap", "Rangasami L.", "" ] ]
1304.1126
F. Correa da Silva
F. Correa da Silva, Alan Bundy
On Some Equivalence Relations between Incidence Calculus and Dempster-Shafer Theory of Evidence
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-378-383
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Incidence Calculus and Dempster-Shafer Theory of Evidence are both theories to describe agents' degrees of belief in propositions, thus being appropriate to represent uncertainty in reasoning systems. This paper presents a straightforward equivalence proof between some special cases of these theories.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:47 GMT" } ]
1,365,120,000,000
[ [ "da Silva", "F. Correa", "" ], [ "Bundy", "Alan", "" ] ]
1304.1127
Mary McLeish
Mary McLeish, P. Yao, T. Stirtzinger
Using Belief Functions for Uncertainty Management and Knowledge Acquisition: An Expert Application
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-384-391
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper describes recent work on an ongoing project in medical diagnosis at the University of Guelph. A domain on which experts are not very good at pinpointing a single disease outcome is explored. On-line medical data is available over a relatively short period of time. Belief Functions (Dempster-Shafer theory) are first extracted from data and then modified with expert opinions. Several methods for doing this are compared and results show that one formulation statistically outperforms the others, including a method suggested by Shafer. Expert opinions and statistically derived information about dependencies among symptoms are also compared. The benefits of using uncertainty management techniques as methods for knowledge acquisition from data are discussed.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:53 GMT" } ]
1,365,120,000,000
[ [ "McLeish", "Mary", "" ], [ "Yao", "P.", "" ], [ "Stirtzinger", "T.", "" ] ]
1304.1128
Robert Fung
Robert Fung, S. L. Crawford, Lee A. Appelbaum, Richard M. Tong
An Architecture for Probabilistic Concept-Based Information Retrieval
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-392-404
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
While concept-based methods for information retrieval can provide improved performance over more conventional techniques, they require large amounts of effort to acquire the concepts and their qualitative and quantitative relationships. This paper discusses an architecture for probabilistic concept-based information retrieval which addresses the knowledge acquisition problem. The architecture makes use of the probabilistic networks technology for representing and reasoning about concepts and includes a knowledge acquisition component which partially automates the construction of concept knowledge bases from data. We describe two experiments that apply the architecture to the task of retrieving documents about terrorism from a set of documents from the Reuters news service. The experiments provide positive evidence that the architecture design is feasible and that there are advantages to concept-based methods.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:58:58 GMT" } ]
1,365,120,000,000
[ [ "Fung", "Robert", "" ], [ "Crawford", "S. L.", "" ], [ "Appelbaum", "Lee A.", "" ], [ "Tong", "Richard M.", "" ] ]
1304.1129
A. J. Hanson
A. J. Hanson
Amplitude-Based Approach to Evidence Accumulation
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-405-414
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We point out the need to use probability amplitudes rather than probabilities to model evidence accumulation in decision processes involving real physical sensors. Optical information processing systems are given as typical examples of systems that naturally gather evidence in this manner. We derive a new, amplitude-based generalization of the Hough transform technique used for object recognition in machine vision. We argue that one should use complex Hough accumulators and square their magnitudes to get a proper probabilistic interpretation of the likelihood that an object is present. Finally, we suggest that probability amplitudes may have natural applications in connectionist models, as well as in formulating knowledge-based reasoning problems.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:04 GMT" } ]
1,365,120,000,000
[ [ "Hanson", "A. J.", "" ] ]
1304.1130
Kathryn Blackmond Laskey
Kathryn Blackmond Laskey
A Probabilistic Reasoning Environment
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-415-422
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A framework is presented for a computational theory of probabilistic argument. The Probabilistic Reasoning Environment encodes knowledge at three levels. At the deepest level are a set of schemata encoding the system's domain knowledge. This knowledge is used to build a set of second-level arguments, which are structured for efficient recapture of the knowledge used to construct them. Finally, at the top level is a Bayesian network constructed from the arguments. The system is designed to facilitate not just propagation of beliefs and assimilation of evidence, but also the dynamic process of constructing a belief network, evaluating its adequacy, and revising it when necessary.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:09 GMT" } ]
1,365,120,000,000
[ [ "Laskey", "Kathryn Blackmond", "" ] ]
1304.1131
Hung-Trung Nguyen
Hung-Trung Nguyen
On Non-monotonic Conditional Reasoning
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-423-427
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This note is concerned with a formal analysis of the problem of non-monotonic reasoning in intelligent systems, especially when the uncertainty is taken into account in a quantitative way. A firm connection between logic and probability is established by introducing conditioning notions by means of formal structures that do not rely on quantitative measures. The associated conditional logic, compatible with conditional probability evaluations, is non-monotonic relative to additional evidence. Computational aspects of conditional probability logic are mentioned. The importance of this development lies on its role to provide a conceptual basis for various forms of evidence combination and on its significance to unify multi-valued and non-monotonic logics
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:14 GMT" } ]
1,365,120,000,000
[ [ "Nguyen", "Hung-Trung", "" ] ]
1304.1132
Michael Pittarelli
Michael Pittarelli
Decisions with Limited Observations over a Finite Product Space: the Klir Effect
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-428-435
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Probability estimation by maximum entropy reconstruction of an initial relative frequency estimate from its projection onto a hypergraph model of the approximate conditional independence relations exhibited by it is investigated. The results of this study suggest that use of this estimation technique may improve the quality of decisions that must be made on the basis of limited observations over a decomposable finite product space.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:20 GMT" } ]
1,365,120,000,000
[ [ "Pittarelli", "Michael", "" ] ]
1304.1133
Stuart Russell
Stuart Russell
Fine-Grained Decision-Theoretic Search Control
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-436-442
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Decision-theoretic control of search has previously used as its basic unit. of computation the generation and evaluation of a complete set of successors. Although this simplifies analysis, it results in some lost opportunities for pruning and satisficing. This paper therefore extends the analysis of the value of computation to cover individual successor evaluations. The analytic techniques used may prove useful for control of reasoning in more general settings. A formula is developed for the expected value of a node, k of whose n successors have been evaluated. This formula is used to estimate the value of expanding further successors, using a general formula for the value of a computation in game-playing developed in earlier work. We exhibit an improved version of the MGSS* algorithm, giving empirical results for the game of Othello.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:26 GMT" } ]
1,365,120,000,000
[ [ "Russell", "Stuart", "" ] ]
1304.1134
Nic Wilson
Nic Wilson
Rules, Belief Functions and Default Logic
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-443-449
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper describes a natural framework for rules, based on belief functions, which includes a repre- sentation of numerical rules, default rules and rules allowing and rules not allowing contraposition. In particular it justifies the use of the Dempster-Shafer Theory for representing a particular class of rules, Belief calculated being a lower probability given certain independence assumptions on an underlying space. It shows how a belief function framework can be generalised to other logics, including a general Monte-Carlo algorithm for calculating belief, and how a version of Reiter's Default Logic can be seen as a limiting case of a belief function formalism.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:32 GMT" } ]
1,365,120,000,000
[ [ "Wilson", "Nic", "" ] ]
1304.1135
Michael S. K. M. Wong
Michael S. K. M. Wong, P. Lingras
Combination of Evidence Using the Principle of Minimum Information Gain
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-450-459
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One of the most important aspects in any treatment of uncertain information is the rule of combination for updating the degrees of uncertainty. The theory of belief functions uses the Dempster rule to combine two belief functions defined by independent bodies of evidence. However, with limited dependency information about the accumulated belief the Dempster rule may lead to unsatisfactory results. The present study suggests a method to determine the accumulated belief based on the premise that the information gain from the combination process should be minimum. This method provides a mechanism that is equivalent to the Bayes rule when all the conditional probabilities are available and to the Dempster rule when the normalization constant is equal to one. The proposed principle of minimum information gain is shown to be equivalent to the maximum entropy formalism, a special case of the principle of minimum cross-entropy. The application of this principle results in a monotonic increase in belief with accumulation of consistent evidence. The suggested approach may provide a more reasonable criterion for identifying conflicts among various bodies of evidence.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:37 GMT" } ]
1,365,120,000,000
[ [ "Wong", "Michael S. K. M.", "" ], [ "Lingras", "P.", "" ] ]
1304.1136
Thomas D. Wu
Thomas D. Wu
Probabilistic Evaluation of Candidates and Symptom Clustering for Multidisorder Diagnosis
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-460-467
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper derives a formula for computing the conditional probability of a set of candidates, where a candidate is a set of disorders that explain a given set of positive findings. Such candidate sets are produced by a recent method for multidisorder diagnosis called symptom clustering. A symptom clustering represents a set of candidates compactly as a cartesian product of differential diagnoses. By evaluating the probability of a candidate set, then, a large set of candidates can be validated or pruned simultaneously. The probability of a candidate set is then specialized to obtain the probability of a single candidate. Unlike earlier results, the equation derived here allows the specification of positive, negative, and unknown symptoms and does not make assumptions about disorders not in the candidate.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:43 GMT" } ]
1,365,120,000,000
[ [ "Wu", "Thomas D.", "" ] ]
1304.1137
John Yen
John Yen, Piero P. Bonissone
Extending Term Subsumption systems for Uncertainty Management
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-468-474
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A major difficulty in developing and maintaining very large knowledge bases originates from the variety of forms in which knowledge is made available to the KB builder. The objective of this research is to bring together two complementary knowledge representation schemes: term subsumption languages, which represent and reason about defining characteristics of concepts, and proximate reasoning models, which deal with uncertain knowledge and data in expert systems. Previous works in this area have primarily focused on probabilistic inheritance. In this paper, we address two other important issues regarding the integration of term subsumption-based systems and approximate reasoning models. First, we outline a general architecture that specifies the interactions between the deductive reasoner of a term subsumption system and an approximate reasoner. Second, we generalize the semantics of terminological language so that terminological knowledge can be used to make plausible inferences. The architecture, combined with the generalized semantics, forms the foundation of a synergistic tight integration of term subsumption systems and approximate reasoning models.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:48 GMT" } ]
1,365,120,000,000
[ [ "Yen", "John", "" ], [ "Bonissone", "Piero P.", "" ] ]
1304.1138
Kuo-Chu Chang
Kuo-Chu Chang, Robert Fung
Refinement and Coarsening of Bayesian Networks
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-475-482
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In almost all situation assessment problems, it is useful to dynamically contract and expand the states under consideration as assessment proceeds. Contraction is most often used to combine similar events or low probability events together in order to reduce computation. Expansion is most often used to make distinctions of interest which have significant probability in order to improve the quality of the assessment. Although other uncertainty calculi, notably Dempster-Shafer [Shafer, 1976], have addressed these operations, there has not yet been any approach of refining and coarsening state spaces for the Bayesian Network technology. This paper presents two operations for refining and coarsening the state space in Bayesian Networks. We also discuss their practical implications for knowledge acquisition.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 13:59:54 GMT" } ]
1,365,120,000,000
[ [ "Chang", "Kuo-Chu", "" ], [ "Fung", "Robert", "" ] ]
1304.1139
Gerhard Paa{\ss}
Gerhard Paa{\ss}
Second Order Probabilities for Uncertain and Conflicting Evidence
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-483-490
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper the elicitation of probabilities from human experts is considered as a measurement process, which may be disturbed by random 'measurement noise'. Using Bayesian concepts a second order probability distribution is derived reflecting the uncertainty of the input probabilities. The algorithm is based on an approximate sample representation of the basic probabilities. This sample is continuously modified by a stochastic simulation procedure, the Metropolis algorithm, such that the sequence of successive samples corresponds to the desired posterior distribution. The procedure is able to combine inconsistent probabilities according to their reliability and is applicable to general inference networks with arbitrary structure. Dempster-Shafer probability mass functions may be included using specific measurement distributions. The properties of the approach are demonstrated by numerical experiments.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:00 GMT" } ]
1,365,120,000,000
[ [ "Paaß", "Gerhard", "" ] ]
1304.1140
Linda C. van der Gaag
Linda C. van der Gaag
Computing Probability Intervals Under Independency Constraints
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-491-497
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many AI researchers argue that probability theory is only capable of dealing with uncertainty in situations where a full specification of a joint probability distribution is available, and conclude that it is not suitable for application in knowledge-based systems. Probability intervals, however, constitute a means for expressing incompleteness of information. We present a method for computing such probability intervals for probabilities of interest from a partial specification of a joint probability distribution. Our method improves on earlier approaches by allowing for independency relationships between statistical variables to be exploited.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:05 GMT" } ]
1,365,120,000,000
[ [ "van der Gaag", "Linda C.", "" ] ]
1304.1141
Michael Shwe
Michael Shwe, Gregory F. Cooper
An Empirical Analysis of Likelihood-Weighting Simulation on a Large, Multiply-Connected Belief Network
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-498-508
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We analyzed the convergence properties of likelihood- weighting algorithms on a two-level, multiply connected, belief-network representation of the QMR knowledge base of internal medicine. Specifically, on two difficult diagnostic cases, we examined the effects of Markov blanket scoring, importance sampling, demonstrating that the Markov blanket scoring and self-importance sampling significantly improve the convergence of the simulation on our model.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:12 GMT" } ]
1,365,120,000,000
[ [ "Shwe", "Michael", "" ], [ "Cooper", "Gregory F.", "" ] ]
1304.1142
David Sher
David Sher
Towards a Normative Theory of Scientific Evidence
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-509-517
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A scientific reasoning system makes decisions using objective evidence in the form of independent experimental trials, propositional axioms, and constraints on the probabilities of events. As a first step towards this goal, we propose a system that derives probability intervals from objective evidence in those forms. Our reasoning system can manage uncertainty about data and rules in a rule based expert system. We expect that our system will be particularly applicable to diagnosis and analysis in domains with a wealth of experimental evidence such as medicine. We discuss limitations of this solution and propose future directions for this research. This work can be considered a generalization of Nilsson's "probabilistic logic" [Nil86] to intervals and experimental observations.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:17 GMT" } ]
1,365,120,000,000
[ [ "Sher", "David", "" ] ]
1304.1143
Mary McLeish
Mary McLeish
A Model for Non-Monotonic Reasoning Using Dempster's Rule
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-518-528
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Considerable attention has been given to the problem of non-monotonic reasoning in a belief function framework. Earlier work (M. Ginsberg) proposed solutions introducing meta-rules which recognized conditional independencies in a probabilistic sense. More recently an e-calculus formulation of default reasoning (J. Pearl) shows that the application of Dempster's rule to a non-monotonic situation produces erroneous results. This paper presents a new belief function interpretation of the problem which combines the rules in a way which is more compatible with probabilistic results and respects conditions of independence necessary for the application of Dempster's combination rule. A new general framework for combining conflicting evidence is also proposed in which the normalization factor becomes modified. This produces more intuitively acceptable results.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:23 GMT" } ]
1,365,120,000,000
[ [ "McLeish", "Mary", "" ] ]
1304.1144
Philippe Smets
Philippe Smets, Yen-Teh Hsia
Default Reasoning and the Transferable Belief Model
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-529-537
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Inappropriate use of Dempster's rule of combination has led some authors to reject the Dempster-Shafer model, arguing that it leads to supposedly unacceptable conclusions when defaults are involved. A most classic example is about the penguin Tweety. This paper will successively present: the origin of the miss-management of the Tweety example; two types of default; the correct solution for both types based on the transferable belief model (our interpretation of the Dempster-Shafer model (Shafer 1976, Smets 1988)); Except when explicitly stated, all belief functions used in this paper are simple support functions, i.e. belief functions for which only one proposition (the focus) of the frame of discernment receives a positive basic belief mass with the remaining mass being given to the tautology. Each belief function will be described by its focus and the weight of the focus (e.g. m(A)=.9). Computation of the basic belief masses are always performed by vacuously extending each belief function to the product space built from all variables involved, combining them on that space by Dempster's rule of combination, and projecting the result to the space corresponding to each individual variable.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:29 GMT" } ]
1,365,120,000,000
[ [ "Smets", "Philippe", "" ], [ "Hsia", "Yen-Teh", "" ] ]
1304.1145
Dan Geiger
Dan Geiger, David Heckerman
Separable and transitive graphoids
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-538-545
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We examine three probabilistic formulations of the sentence a and b are totally unrelated with respect to a given set of variables U. First, two variables a and b are totally independent if they are independent given any value of any subset of the variables in U. Second, two variables are totally uncoupled if U can be partitioned into two marginally independent sets containing a and b respectively. Third, two variables are totally disconnected if the corresponding nodes are disconnected in every belief network representation. We explore the relationship between these three formulations of unrelatedness and explain their relevance to the process of acquiring probabilistic knowledge from human experts.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:34 GMT" }, { "version": "v2", "created": "Sun, 19 May 2013 19:42:17 GMT" }, { "version": "v3", "created": "Sat, 16 May 2015 23:58:55 GMT" } ]
1,431,993,600,000
[ [ "Geiger", "Dan", "" ], [ "Heckerman", "David", "" ] ]
1304.1146
Bo Chamberlain
Bo Chamberlain, Finn Verner Jensen, Frank Jensen, Torsten Nordahl
Analysis in HUGIN of Data Conflict
Appears in Proceedings of the Sixth Conference on Uncertainty in Artificial Intelligence (UAI1990)
null
null
UAI-P-1990-PG-546-554
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
After a brief introduction to causal probabilistic networks and the HUGIN approach, the problem of conflicting data is discussed. A measure of conflict is defined, and it is used in the medical diagnostic system MUNIN. Finally, it is discussed how to distinguish between conflicting data and a rare case.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 14:00:40 GMT" } ]
1,365,120,000,000
[ [ "Chamberlain", "Bo", "" ], [ "Jensen", "Finn Verner", "" ], [ "Jensen", "Frank", "" ], [ "Nordahl", "Torsten", "" ] ]
1304.1402
Bernardo Cuenca Grau
Bernardo Cuenca Grau, Boris Motik, Giorgos Stoilos, Ian Horrocks
Computing Datalog Rewritings beyond Horn Ontologies
14 pages. To appear at IJCAI 2013
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Rewriting-based approaches for answering queries over an OWL 2 DL ontology have so far been developed mainly for Horn fragments of OWL 2 DL. In this paper, we study the possibilities of answering queries over non-Horn ontologies using datalog rewritings. We prove that this is impossible in general even for very simple ontology languages, and even if PTIME = NP. Furthermore, we present a resolution-based procedure for $\SHI$ ontologies that, in case it terminates, produces a datalog rewriting of the ontology. Our procedure necessarily terminates on DL-Lite_{bool}^H ontologies---an extension of OWL 2 QL with transitive roles and Boolean connectives.
[ { "version": "v1", "created": "Thu, 4 Apr 2013 15:31:45 GMT" }, { "version": "v2", "created": "Mon, 8 Apr 2013 10:49:12 GMT" } ]
1,365,465,600,000
[ [ "Grau", "Bernardo Cuenca", "" ], [ "Motik", "Boris", "" ], [ "Stoilos", "Giorgos", "" ], [ "Horrocks", "Ian", "" ] ]
1304.1491
Fahiem Bacchus
Fahiem Bacchus
Lp : A Logic for Statistical Information
Appears in Proceedings of the Fifth Conference on Uncertainty in Artificial Intelligence (UAI1989)
null
null
UAI-P-1989-PG-1-6
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This extended abstract presents a logic, called Lp, that is capable of representing and reasoning with a wide variety of both qualitative and quantitative statistical information. The advantage of this logical formalism is that it offers a declarative representation of statistical knowledge; knowledge represented in this manner can be used for a variety of reasoning tasks. The logic differs from previous work in probability logics in that it uses a probability distribution over the domain of discourse, whereas most previous work (e.g., Nilsson [2], Scott et al. [3], Gaifinan [4], Fagin et al. [5]) has investigated the attachment of probabilities to the sentences of the logic (also, see Halpern [6] and Bacchus [7] for further discussion of the differences). The logic Lp possesses some further important features. First, Lp is a superset of first order logic, hence it can represent ordinary logical assertions. This means that Lp provides a mechanism for integrating statistical information and reasoning about uncertainty into systems based solely on logic. Second, Lp possesses transparent semantics, based on sets and probabilities of those sets. Hence, knowledge represented in Lp can be understood in terms of the simple primative concepts of sets and probabilities. And finally, the there is a sound proof theory that has wide coverage (the proof theory is complete for certain classes of models). The proof theory captures a sufficient range of valid inferences to subsume most previous probabilistic uncertainty reasoning systems. For example, the linear constraints like those generated by Nilsson's probabilistic entailment [2] can be generated by the proof theory, and the Bayesian inference underlying belief nets [8] can be performed. In addition, the proof theory integrates quantitative and qualitative reasoning as well as statistical and logical reasoning. In the next section we briefly examine previous work in probability logics, comparing it to Lp. Then we present some of the varieties of statistical information that Lp is capable of expressing. After this we present, briefly, the syntax, semantics, and proof theory of the logic. We conclude with a few examples of knowledge representation and reasoning in Lp, pointing out the advantages of the declarative representation offered by Lp. We close with a brief discussion of probabilities as degrees of belief, indicating how such probabilities can be generated from statistical knowledge encoded in Lp. The reader who is interested in a more complete treatment should consult Bacchus [7].
[ { "version": "v1", "created": "Wed, 27 Mar 2013 19:36:47 GMT" } ]
1,365,379,200,000
[ [ "Bacchus", "Fahiem", "" ] ]
1304.1492
Kenneth Basye
Kenneth Basye, Thomas L. Dean
Map Learning with Indistinguishable Locations
Appears in Proceedings of the Fifth Conference on Uncertainty in Artificial Intelligence (UAI1989)
null
null
UAI-P-1989-PG-7-13
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Nearly all spatial reasoning problems involve uncertainty of one sort or another. Uncertainty arises due to the inaccuracies of sensors used in measuring distances and angles. We refer to this as directional uncertainty. Uncertainty also arises in combining spatial information when one location is mistakenly identified with another. We refer to this as recognition uncertainty. Most problems in constructing spatial representations (maps) for the purpose of navigation involve both directional and recognition uncertainty. In this paper, we show that a particular class of spatial reasoning problems involving the construction of representations of large-scale space can be solved efficiently even in the presence of directional and recognition uncertainty. We pay particular attention to the problems that arise due to recognition uncertainty.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 19:36:53 GMT" } ]
1,365,379,200,000
[ [ "Basye", "Kenneth", "" ], [ "Dean", "Thomas L.", "" ] ]
1304.1493
Carlo Berzuini
Carlo Berzuini, Riccardo Bellazzi, Silvana Quaglini
Temporal Reasoning with Probabilities
Appears in Proceedings of the Fifth Conference on Uncertainty in Artificial Intelligence (UAI1989)
null
null
UAI-P-1989-PG-14-21
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we explore representations of temporal knowledge based upon the formalism of Causal Probabilistic Networks (CPNs). Two different ?continuous-time? representations are proposed. In the first, the CPN includes variables representing ?event-occurrence times?, possibly on different time scales, and variables representing the ?state? of the system at these times. In the second, the CPN describes the influences between random variables with values in () representing dates, i.e. time-points associated with the occurrence of relevant events. However, structuring a system of inter-related dates as a network where all links commit to a single specific notion of cause and effect is in general far from trivial and leads to severe difficulties. We claim that we should recognize explicitly different kinds of relation between dates, such as ?cause?, ?inhibition?, ?competition?, etc., and propose a method whereby these relations are coherently embedded in a CPN using additional auxiliary nodes corresponding to "instrumental" variables. Also discussed, though not covered in detail, is the topic concerning how the quantitative specifications to be inserted in a temporal CPN can be learned from specific data.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 19:36:59 GMT" } ]
1,365,379,200,000
[ [ "Berzuini", "Carlo", "" ], [ "Bellazzi", "Riccardo", "" ], [ "Quaglini", "Silvana", "" ] ]
1304.1494
Piero P. Bonissone
Piero P. Bonissone
Now that I Have a Good Theory of Uncertainty, What Else Do I Need?
Appears in Proceedings of the Fifth Conference on Uncertainty in Artificial Intelligence (UAI1989)
null
null
UAI-P-1989-PG-22-33
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Rather than discussing the isolated merits of a nominative theory of uncertainty, this paper focuses on a class of problems, referred to as Dynamic Classification Problem (DCP), which requires the integration of many theories, including a prescriptive theory of uncertainty. We start by analyzing the Dynamic Classification Problem and by defining its induced requirements on a supporting (plausible) reasoning system. We provide a summary of the underlying theory (based on the semantics of many-valed logics) and illustrate the constraints imposed upon it to ensure the modularity and computational performance required by the applications. We describe the technologies used for knowledge engineering (such as object-based simulator to exercise requirements, and development tools to build the Knowledge Base and functionally validate it). We emphasize the difference between development environment and run-time system, describe the rule cross-compiler, and the real-time inference engine with meta-reasoning capabilities. Finally, we illustrate how our proposed technology satisfies the pop's requirements and analyze some of the lessons reamed from its applications to situation assessment problems for Pilot's Associate and Submarine Commander Associate.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 19:37:05 GMT" } ]
1,365,379,200,000
[ [ "Bonissone", "Piero P.", "" ] ]
1304.1495
Piero P. Bonissone
Piero P. Bonissone, David A. Cyrluk, James W. Goodwin, Jonathan Stillman
Uncertainty and Incompleteness
Appears in Proceedings of the Fifth Conference on Uncertainty in Artificial Intelligence (UAI1989)
null
null
UAI-P-1989-PG-34-45
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two major difficulties in using default logics are their intractability and the problem of selecting among multiple extensions. We propose an approach to these problems based on integrating nommonotonic reasoning with plausible reasoning based on triangular norms. A previously proposed system for reasoning with uncertainty (RUM) performs uncertain monotonic inferences on an acyclic graph. We have extended RUM to allow nommonotonic inferences and cycles within nonmonotonic rules. By restricting the size and complexity of the nommonotonic cycles we can still perform efficient inferences. Uncertainty measures provide a basis for deciding among multiple defaults. Different algorithms and heuristics for finding the optimal defaults are discussed.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 19:37:11 GMT" } ]
1,365,379,200,000
[ [ "Bonissone", "Piero P.", "" ], [ "Cyrluk", "David A.", "" ], [ "Goodwin", "James W.", "" ], [ "Stillman", "Jonathan", "" ] ]
1304.1496
Lashon B. Booker
Lashon B. Booker, Naveen Hota, Connie Loggia Ramsey
BaRT: A Bayesian Reasoning Tool for Knowledge Based Systems
Appears in Proceedings of the Fifth Conference on Uncertainty in Artificial Intelligence (UAI1989)
null
null
UAI-P-1989-PG-46-53
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
As the technology for building knowledge based systems has matured, important lessons have been learned about the relationship between the architecture of a system and the nature of the problems it is intended to solve. We are implementing a knowledge engineering tool called BART that is designed with these lessons in mind. BART is a Bayesian reasoning tool that makes belief networks and other probabilistic techniques available to knowledge engineers building classificatory problem solvers. BART has already been used to develop a decision aid for classifying ship images, and it is currently being used to manage uncertainty in systems concerned with analyzing intelligence reports. This paper discusses how state-of-the-art probabilistic methods fit naturally into a knowledge based approach to classificatory problem solving, and describes the current capabilities of BART.
[ { "version": "v1", "created": "Wed, 27 Mar 2013 19:37:17 GMT" } ]
1,365,379,200,000
[ [ "Booker", "Lashon B.", "" ], [ "Hota", "Naveen", "" ], [ "Ramsey", "Connie Loggia", "" ] ]