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1.
Knowledge-base V&V primarily addresses the question: “Does my knowledge-base contain the right answer and can I arrive at it?” One of the main goals of our work is to properly encapsulate the knowledge representation and allow the expert to work with manageable-sized chunks of the knowledge-base. This work develops a new methodology for the verification and validation of Bayesian knowledge-bases that assists in constructing and testing such knowledge-bases. Assistance takes the form of ensuring that the knowledge is syntactically correct, correcting “imperfect” knowledge, and also identifying when the current knowledge-base is insufficient as well as suggesting ways to resolve this insufficiency. The basis of our approach is the use of probabilistic network models of knowledge. This provides a framework for formally defining and working on the problems of uncertainty in the knowledge-base.
In this paper, we examine the project which is concerned with assisting a human expert to build knowledge-based systems under uncertainty. We focus on how verification and validation are currently achieved in . 相似文献
2.
A comprehensive framework for project selection problem under uncertainty and real-world constraints 总被引:1,自引:0,他引:1
This paper proposes a comprehensive framework for project selection problem under uncertainty and subject to real-world constraints, like segmentation, logical, and budget constraints. The framework consists of two main phases. In the first phase, the candidate projects are ranked considering the uncertainty, through a Monte Carlo simulation linked to a multi-criteria approach. In the second phase, the overall complete preorder of the projects in different iterations is first determined and then used in another Monte Carlo simulation linked to an integer programming module in order to effectively drive the final portfolio selection while satisfying the budget, segmentation and other logical constraints. The proposed framework is implemented in a case study to show its usefulness and applicability in practice. Finally, a comparison is carried out between the proposed approach and its deterministic counterpart and the corresponding results are discussed. 相似文献
3.
常识知识的研究与发展得到了人工智能界的很大重视。文章建立了一个基于常识的人物亲属关系推理模型,研究了亲属关系常识以及人物信息的表示与存储。此外,对实际所要解决的问题进行了总结。 相似文献
4.
5.
A general framework for reasoning about change 总被引:1,自引:0,他引:1
Juan Carlos Augusto 《New Generation Computing》2003,21(3):209-246
The capability to represent and use concepts like time and events in computer science is essential to solve a wide class of
problems characterized by the notion of change. Real-time, databases and multimedia are just a few of several areas which
needs good tools to deal with time. Another area where this concepts are essential is artificial intelligence because an agent
must be able to reason about a dynamic environment.
In this work a formalism is proposed which allows the representation and use of several features that had been recognized
as useful in the attempts to solve such class of problems. A general framework based on a many-sorted logic is proposed centering
our attention in issues such as the representation of time, actions, properties, events and causality. The proposal is compared
with related work from the temporal logic and artificial intelligence areas. This work complements and enhances previously
related efforts on formalizing temporal concepts with the same purpose.
Juan Carlos Augusto, Ph.D.: He is a Lecturer in the Department of Computer Science at Universidad Nacional del Sur (Argentina), where he graduated as
Licenciado en Ciencias de la Computacion and Doctor en Ciencias de la Computacion. Currently on leave in the Department of
Electronics and Computer Science, University of Southampton (United Kingdom). His research interests are focused in the dynamic
aspects of computing systems. This involves solving conceptual problems related to the specification of time and change and
designing tools to improve systems in several areas of computer science, such as artificial intelligence, databases, multimedia,
software verification and real-time systems. He has been conducting research on temporal representation and reasoning since
1993. Throughout these years he had the opportunity to contribute to several research projects as a researcher and has head
or co-head of research groups. Other activities and contributions to highlight are the organization of international events,
editorial work and supervision of postgraduate students, all of which contributes to the generation and dissemination of knowledge
about the dynamic aspects of computing systems. 相似文献
6.
When combining logic level theorem proving with computational methods it is important to identify both functions that can be efficiently computed and the objects they can be applied to. This is generally achieved by mappings of logic level terms and functions to their computational counterparts. However, these mappings are often quite ad hoc and fragile depending very much on the particular logic representations of terms. We present a method of annotating terms in logic proofs with their computational properties. This enables the compact representation of computational objects in deduction systems as well as their connection to functions that can be easily computed for them. This eases the identification of deduction problems that can be treated efficiently by computational methods and also abstracts from trivial properties that are artefacts of a particular representation. We ensure logical correctness of our concepts by providing the possibility to replace terms by their logical representation and by expanding computational procedures by tactic application that can be rigorously checked. 相似文献
7.
基于模糊推理的多媒体农业专家系统及其开发工具 总被引:4,自引:1,他引:4
该文应用面向对象思想和方法,分析了农业知识的特点,设计并实现了一个农业专家系统的开发工具,并使用该开发工具设计了花椰菜栽培技术专家系统和龙眼栽培技术专家系统。 相似文献
8.
This paper present an extension of traditional logic programming, called ordered logic (OL) programming, to support classical
negation as well as constructs from the object-oriented paradigm. In particular, such an extension allows to cope with the
notions of object, multiple inheritance and non-monotonic reasoning.
The contribution of the work is mainly twofold. First, a rich wellfounded semantics for ordered logic programs is defined.
Second, an efficient method for the well-founded model computation of a meaningful class of ordered logic programs, called
stratified programs, is provided. 相似文献
9.
本文根据对agent中知识认知程度,分析了知识的动态,不确定性的性质,使用动态模糊逻辑用于agent的知识表示,并给出了相关计算方法. 相似文献
10.
本文根据对agent中知识认知程度,分析了知识的动态,不确定性的性质,使用动态模糊逻辑用于agent的知识表示,并给出了相关计算方法。 相似文献
11.
Collaborative robust optimization under uncertainty based on generalized dynamic constraints network
W. M. Wang Y. H. Peng J. Hu Z. M. Cao 《Structural and Multidisciplinary Optimization》2009,38(2):159-170
Uncertainties exist in every aspect of a collaborative multidisciplinary design process. These uncertainties will have a great
influence on design negotiations between various disciplines and may force designers to make conservative decisions. In this
paper, a novel collaborative robust optimization (CRO) method based on constraints network under uncertainty is presented.
The generalized dynamic constraints network (GDCN) is developed to analysis and management of uncertainties, and to ensure
the parameter consistency in the collaborative design process. Given the feasible consistent parameter region, The CRO is
formulated as a multi-criteria optimization problem, which brings both the objective robustness and the feasibility robustness
of the constraint into account simultaneously. The CRO based on GDCN could bring both the design parameters dynamic consistency
management and robust optimization into account simultaneously, which assures a product’s reliability and quality robustness.
The efficiency of proposed method is evaluated in the design of crank and connecting rod in one V6 engine. 相似文献
12.
Massimo Esposito Giuseppe De Pietro 《Engineering Applications of Artificial Intelligence》2011,24(8):1340-1354
The use of Magnetic Resonance (MR) as a supporting tool in the diagnosis and monitoring of multiple sclerosis (MS) and in the assessment of treatment effects requires the accurate determination of cerebral white matter lesion (WML) volumes. In order to automatically support neuroradiologists in the classification of WMLs, an ontology-based fuzzy decision support system (DSS) has been devised and implemented. The DSS encodes high-level, specialized medical knowledge in terms of ontologies and fuzzy rules and applies this knowledge in conjunction with a fuzzy inference engine to classify WMLs and to obtain a measure of their volumes. The performance of the DSS has been quantitatively evaluated on 120 patients affected by MS. Specifically, binary classification results have been first obtained by applying thresholds on fuzzy outputs and then evaluated, by means of ROC curves, in terms of trade-off between sensitivity and specificity. Similarity measures of WMLs have been also computed for a further quantitative analysis. Moreover, a statistical analysis has been carried out for appraising the DSS influence on the diagnostic tasks of physicians. The evaluation has shown that the DSS offers an innovative and valuable way to perform automated WML classification in real clinical settings. 相似文献
13.
Databases with uncertainty and lineage 总被引:2,自引:0,他引:2
Omar Benjelloun Anish Das Sarma Alon Halevy Martin Theobald Jennifer Widom 《The VLDB Journal The International Journal on Very Large Data Bases》2008,17(2):243-264
This paper introduces uldbs, an extension of relational databases with simple yet expressive constructs for representing and manipulating both lineage and uncertainty. Uncertain data and data lineage are two important areas of data management that have been considered extensively in isolation,
however many applications require the features in tandem. Fundamentally, lineage enables simple and consistent representation
of uncertain data, it correlates uncertainty in query results with uncertainty in the input data, and query processing with
lineage and uncertainty together presents computational benefits over treating them separately. We show that the uldb representation is complete, and that it permits straightforward implementation of many relational operations. We define two notions of uldb minimality—data-minimal and lineage-minimal—and study minimization of uldb representations under both notions. With lineage, derived relations are no longer self-contained: their uncertainty depends
on uncertainty in the base data. We provide an algorithm for the new operation of extracting a database subset in the presence
of interconnected uncertainty. We also show how uldbs enable a new approach to query processing in probabilistic databases. Finally, we describe the current state of the Trio system, our implementation of uldbs under development at Stanford.
This work was supported by the National Science Foundation under grants IIS-0324431, IIS-1098447, and IIS-9985114, by DARPA
Contract #03-000225, and by a grant from the Boeing Corporation. 相似文献
14.
因果图用于复杂系统故障诊断研究 总被引:14,自引:0,他引:14
在信度网基础上发展起来的因果图模型,克服了信度网的一些不足,具有重要的工业应用价值。经过文献犤5犦犤6犦犤7犦的研究,目前因果图已发展成一个能够处理离散变量和连续变量的混合因果图模型。文章讨论了将因果图用于复杂系统故障诊断的关键问题。给出了基于因果图的故障知识表达方法,给出了故障模式的静态求取方法和动态求取方法以及故障模式的概率计算方法。以核电站二回路系统为研究对象,在自行研制的因果图智能故障诊断平台上进行了故障诊断测试,诊断结果与实际情况相符,诊断迅速、效果较好。 相似文献
15.
Reasoning aboutfacts and reasoning aboutarguments regarding facts are distinct activities, and automated reasoning systems should be able to treat them accordingly. In this work, we discuss one precise sense in which this distinction can be envisaged and suggest the use of Annotated Logics to characterise it. 相似文献
16.
In this work we establish a framework for the general problem of observation, which may be applied to different kinds of visual tasks. We construct intelligent high-level control mechanisms for active visual recognition of different processes within a hybrid dynamic system. We address the problem of observing a manipulation process in order to illustrate the ideas and motive behind our framework. We use a discrete event dynamic system as a high-level structuring technique to model the manipulation system. The formulation utilizes the knowledge about the system and the different actions in order to solve the observer problem in an efficient, stable and practical manner. The model uses different tracking mechanisms so that the observer can see the workspace of the manipulating robot. An automaton is developed for the hand/object interaction over time and a stabilizing observer is constructed. Low-level modules are developed for recognizing the visual events that causes state transitions within the dynamic manipulation system in real time. A coarse quantization of the manipulation actions is used in order to attain an active, adaptive and goaldirected sensing mechanism. The formulation provides high-level symbolic interpretations of the scene under observation. The discrete event framework is augmented with mechanisms for recovering the continuous parametric evolution of the scene under observation and for asserting the state of the manipulation agent. This work examines closely the possibilities for errors, mistakes and uncertainties in the manipulation system, observer construction process and event identification mechanisms. We identify and suggest techniques for modeling these uncertainties. Ambiguities are allowed to develop and are resolved after finite time. Error recovery mechanisms are also devised. The computed uncertainties are utilized for navigating the observer automaton state space, asserting state transitions and developing a suitable tracking mechanism. 相似文献
17.
文章对专家系统技术在产品维修性设计中的应用进行了研究,提出了该系统的总体结构方案和特点、知识表示和知识获取、推理机技术,并对计算机辅助维修性设计现状进行了简要分析。 相似文献
18.
针对目前公众自行购买非处方药治疗常见轻微疾病的过程中存在的问题,提出了开发基于Web的常见疾病自我诊断系统.该系统采用带有可信度的产生式规则表示法来表示常见病诊断知识,采用正反向混合推理模式,通过可信度的传递以及结论阈值的设定,实现了疾病诊断的数字化.经测试,系统诊断准确度达83%.系统对完善常见病诊断方式、指导公众安全使用非处方药具有积极的作用. 相似文献
19.
《Expert systems with applications》2014,41(6):2713-2728
SysML activity diagrams are OMG/INCOSE standard diagrams used for modeling and specifying probabilistic systems. They support systems composition by call behavior and send/receive artifacts. For verification, the existing approaches dedicated to these diagrams are limited to a restricted set of artifacts. In this paper, we propose a formal verification framework for these diagrams that supports the most important artifacts. It is based on mapping a composition of SysML activity diagrams to the input language of the probabilistic symbolic model checker called “PRISM”. To prove the soundness of our mapping approach, we capture the underlying semantics of both the SysML activity diagrams and their generated PRISM code. We found that the probabilistic equivalence relation between both semantics preserve the satisfaction of the system requirements. Finally, we demonstrate the effectiveness of our approach by presenting real case studies. 相似文献
20.
文章针对海洋渔业资源的多种预测算法得到的结果集,提出了以框架的知识表示理论为基础的不确定规则推理预测系统修正算法,利用框架系统KBIF(Knowledge Base in Frame)的知识表示理论与黑板结构、不确定推理相结合对预测算法根据不同环境参数进行多种方式的修正,可以对系统预测结果进行有效的分析,以期得到更好的应用。 相似文献