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 evidential reasoning


GFDC: A Granule Fusion Density-Based Clustering with Evidential Reasoning

arXiv.org Artificial Intelligence

Currently, density-based clustering algorithms are widely applied because they can detect clusters with arbitrary shapes. However, they perform poorly in measuring global density, determining reasonable cluster centers or structures, assigning samples accurately and handling data with large density differences among clusters. To overcome their drawbacks, this paper proposes a granule fusion density-based clustering with evidential reasoning (GFDC). Both local and global densities of samples are measured by a sparse degree metric first. Then information granules are generated in high-density and low-density regions, assisting in processing clusters with significant density differences. Further, three novel granule fusion strategies are utilized to combine granules into stable cluster structures, helping to detect clusters with arbitrary shapes. Finally, by an assignment method developed from Dempster-Shafer theory, unstable samples are assigned. After using GFDC, a reasonable clustering result and some identified outliers can be obtained. The experimental results on extensive datasets demonstrate the effectiveness of GFDC.


Evidential Reasoning in Image Understanding

arXiv.org Artificial Intelligence

In this paper, we present some results of evidential reasoning in understanding multispectral images of remote sensing systems. The Dempster-Shafer approach of combination of evidences is pursued to yield contextual classification results, which are compared with previous results of the Bayesian context free classification, contextual classifications of dynamic programming and stochastic relaxation approaches.


Deriving And Combining Continuous Possibility Functions in the Framework of Evidential Reasoning

arXiv.org Artificial Intelligence

To develop an approach to utilizing continuous statistical information within the Dempster- Shafer framework, we combine methods proposed by Strat and by Shafero We first derive continuous possibility and mass functions from probability-density functions. Then we propose a rule for combining such evidence that is simpler and more efficiently computed than Dempster's rule. We discuss the relationship between Dempster's rule and our proposed rule for combining evidence over continuous frames.


Evidential Reasoning in Parallel Hierarchical Vision Programs

arXiv.org Artificial Intelligence

This paper presents an efficient adaptation and application of the Dempster-Shafer theory of evidence, one that can be used effectively in a massively parallel hierarchical system for visual pattern perception. It describes the techniques used, and shows in an extended example how they serve to improve the system's performance as it applies a multiple-level set of processes.


Application of Evidential Reasoning to Helicopter Flight Path Control

arXiv.org Artificial Intelligence

This paper presents a methodology for research and development of the inferencing and knowledge representation aspects of an Expert System approach for performing reasoning under uncertainty in support of a real time vehicle guidance and navigation system. Such a system could be of major benefit for non-terrain following low altitude flight systems operating in foreign hostile environments such as might be experienced by NOE helicopter or similar mission craft. An innovative extension of the evidential reasoning methodology, termed the Sum-and-Lattice-Points Method, has been developed. The research and development effort presented in this paper consists of a formal mathematical development of the Sum-and-Lattice-Points Method, its formulation and representation in a parallel environment, prototype software development of the method within an expert system, and initial testing of the system within the confines of the vehicle guidance system.


Implementing Evidential Reasoning in Expert Systems

arXiv.org Artificial Intelligence

However, the theory has not been implemented for reasoning in expert systems due to.its difficulty dealing with uncertain rules. More recently, several extenstions to the theory has been proposed to overcome this difficulty [Yen, 1986a] [Liu, 1986]. Based on Yen's extended DS theory, we have implemented a prototype expert system, named GERTIS (General Evidential Reasoning Tool for Intelligent Systems), that diagnoses rheumatoid arthritis. We chose unspecified polyarthritis as the area of our medical consultation system because the diagnoses form a disease hierarchy, which fits Dempster-Shafer based reasoning best. GERTIS uses the knowledge base of OADIAG-2, a medical expert system developed by Peter Adlassnig [Adlassnig, 1985a,b]. Through the use of OADIAG-2's knowledge base, relevant evidence and rules have been already identified for the area of arthritis. In order to suit the needs of our model, however, the rules of OADIAG-2 were modified and reorganized.


Metaprobability and Dempster-Shafer in Evidential Reasoning

arXiv.org Artificial Intelligence

Evidential reasoning in expert systems has often used ad-hoc uncertainty calculi. Although it is generally accepted that probability theory provides a firm theoretical foundation, researchers have found some problems with its use as a workable uncertainty calculus. Among these problems are representation of ignorance, consistency of probabilistic judgements, and adjustment of a priori judgements with experience. The application of metaprobability theory to evidential reasoning is a new approach to solving these problems. Metaprobability theory can be viewed as a way to provide soft or hard constraints on beliefs in much the same manner as the Dempster-Shafer theory provides constraints on probability masses on subsets of the state space. Thus, we use the Dempster-Shafer theory, an alternative theory of evidential reasoning to illuminate metaprobability theory as a theory of evidential reasoning. The goal of this paper is to compare how metaprobability theory and Dempster-Shafer theory handle the adjustment of beliefs with evidence with respect to a particular thought experiment. Sections 2 and 3 give brief descriptions of the metaprobability and Dempster-Shafer theories. Metaprobability theory deals with higher order probabilities applied to evidential reasoning. Dempster-Shafer theory is a generalization of probability theory which has evolved from a theory of upper and lower probabilities. Section 4 describes a thought experiment and the metaprobability and DempsterShafer analysis of the experiment. The thought experiment focuses on forming beliefs about a population with 6 types of members {1, 2, 3, 4, 5, 6}. A type is uniquely defined by the values of three features: A, B, C. That is, if the three features of one member of the population were known then its type could be ascertained. Each of the three features has two possible values, (e.g. A can be either "a0" or "al"). Beliefs are formed from evidence accrued from two sensors: sensor A, and sensor B. Each sensor senses the corresponding defining feature. Sensor A reports that half of its observations are "a0" and half the observations are 'al'. Sensor B reports that half of its observations are ``b0,' and half are "bl". Based on these two pieces of evidence, what should be the beliefs on the distribution of types in the population? Note that the third feature is not observed by any sensor.


Evidential Reasoning in a Categorial Perspective: Conjunction and Disjunction of Belief Functions

arXiv.org Artificial Intelligence

The categorial approach to evidential reasoning can be seen as a combination of the probability kinematics approach of Richard Jeffrey (1965) and the maximum (cross-) entropy inference approach of E. T. Jaynes (1957). As a consequence of that viewpoint, it is well known that category theory provides natural definitions for logical connectives. In particular, disjunction and conjunction are modelled by general categorial constructions known as products and coproducts. In this paper, I focus mainly on Dempster-Shafer theory of belief functions for which I introduce a category I call Dempster?s category. I prove the existence of and give explicit formulas for conjunction and disjunction in the subcategory of separable belief functions. In Dempster?s category, the new defined conjunction can be seen as the most cautious conjunction of beliefs, and thus no assumption about distinctness (of the sources) of beliefs is needed as opposed to Dempster?s rule of combination, which calls for distinctness (of the sources) of beliefs.


RES - a Relative Method for Evidential Reasoning

arXiv.org Artificial Intelligence

In this paper we describe a novel method for evidential reasoning [1]. It involves modelling the process of evidential reasoning in three steps, namely, evidence structure construction, evidence accumulation, and decision making. The proposed method, called RES, is novel in that evidence strength is associated with an evidential support relationship (an argument) between a pair of statements and such strength is carried by comparison between arguments. This is in contrast to the onventional approaches, where evidence strength is represented numerically and is associated with a statement.


A Target Classification Decision Aid

arXiv.org Artificial Intelligence

A submarine's sonar team is responsible for detecting, localising and classifying targets using information provided by the platform's sensor suite. The information used to make these assessments is typically uncertain and/or incomplete and is likely to require a measure of confidence in its reliability. Moreover, improvements in sensor and communication technology are resulting in increased amounts of on-platform and off-platform information available for evaluation. This proliferation of imprecise information increases the risk of overwhelming the operator. To assist the task of localisation and classification a concept demonstration decision aid (Horizon), based on evidential reasoning, has been developed. Horizon is an information fusion software package for representing and fusing imprecise information about the state of the world, expressed across suitable frames of reference. The Horizon software is currently at prototype stage.