共查询到18条相似文献,搜索用时 93 毫秒
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贝叶斯网络是人工智能中不确定知识表示和推理的有力工具。介绍了贝叶斯网络的概念,给出一个实例,分析了贝叶斯网络推理的方法和过程。 相似文献
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贝叶斯网络是人工智能中不确定知识表示和推理的有力工具.介绍了贝叶斯网络的概念,给出一个实例,分析了贝叶斯网络推理的方法和过程. 相似文献
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贾阳冉 《数字社区&智能家居》2007,3(14):350-351
本文主要探讨了专家系统技术在网络计划工作估算中的应用.首先分析了网络计划的领域知识,并采用面向对象的方法进行知识表示;在推理机制中讨论了在面向对象知识表示情况下的推理流程.最后对ESDENP的结构和主要功能作了介绍. 相似文献
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介绍了多实体贝叶斯网络(MEBN)理论,给出了实体片断及多实体规则形式化的定义,分析了在态势估计中使用多实体贝叶斯网络进行知识表示和态势推理的问题.给出一个具体的实例,演示了使用多实体贝叶斯网络进行态势估计的过程. 相似文献
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一类贝叶斯网络的线性推理 总被引:3,自引:0,他引:3
贝叶斯网络提供了表示变量集之间概率依赖性的一个自然有效的方法,而且其推理方法是主观贝叶斯方法的一个扩展,具有坚实的概率理论基础,因此,许多人工智能的研究者都采用贝叶斯网络作为一种知识表示的方法,将其应用到各种问题领域。如:故事理解、规划、电路错误检测和医学诊断等等。但是,贝叶斯网络已遭受到一些人工智能研究者的批评,因为它们需要大量的数值概率值使不确定关系量化, 相似文献
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贝叶斯学习,贝叶斯网络与数据采掘 总被引:15,自引:1,他引:15
自从50~60年代贝叶斯学派形成后,关于贝叶斯分析的研究久盛不衰。早在80年代,贝叶斯网络就成功地应用于专家系统,成为表示不确定性专家知识和推理的一种流行方法。90年代以来,贝叶斯学习一直是机器学习研究的重要方向。由于概率统计与数据采掘的 相似文献
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Messaouda Fareh 《Applied Artificial Intelligence》2013,27(11):1022-1034
ABSTRACTInteroperable ontologies already exist in the biomedical field, enabling scientists to communicate with minimum ambiguity. Unfortunately, ontology languages, in the semantic web, such as OWL and RDF(S), are based on crisp logic and thus they cannot handle uncertain knowledge about an application field, which is unsuitable for the medical domain. In this paper, we focus on modeling incomplete knowledge in the classical OWL ontologies, using Bayesian networks, all keeping the semantic of the first ontology, and applying algorithms dedicated to learn parameters of Bayesian networks in order to generate the Bayesian networks. We use EM algorithm for learning conditional probability tables of different nodes of Bayesian network automatically, contrary to different tools of Bayesian networks where probabilities are inserted manually. To validate our work, we have applied our model on the diagnosis of liver cancer using classical ontology containing incomplete instances, in order to handle medical uncertain knowledge, for predicting a liver cancer. 相似文献
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因果关系,贝叶斯网络与认知图 总被引:22,自引:0,他引:22
因果关系在预测和推理中具有重要的作用.贝叶斯网络已被用于构建诊断和决策系
统.近年来模糊认知图得到了重视.模糊认知图为结构性知识与因果推理提供了又一个理论
框架.本文简单介绍贝叶斯网络与认知图及其推理方法在智能系统中的应用. 相似文献
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基于遗传算法和强化学习的贝叶斯网络结构学习算法 总被引:1,自引:0,他引:1
遗传算法是基于自然界中生物遗传规律的适应性原则对问题解空间进行搜寻和最优化的方法。贝叶斯网络是对不确定性知识进行建模、推理的主要方法,Bayesian网中的学习问题(参数学习与结构学习)是个NP-hard问题。强化学习是利用新顺序数据来更新学习结果的在线学习方法。介绍了利用强化学习指导遗传算法,实现对贝叶斯网结构进行有效学习。 相似文献
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A framework for the analysis of dynamic processes based on Bayesian networks and case-based reasoning 总被引:2,自引:0,他引:2
Bayesian networks are knowledge representation schemes that can capture probabilistic relationships among variables and perform probabilistic inference. Arrival of new evidence propagates through the network until all variables are updated. At the end of propagation, the network becomes a static snapshot representing the state of the domain for that particular time. This weakness in capturing temporal semantics has limited the use of Bayesian networks to domains in which time dependency is not a critical factor. This paper describes a framework that combines Bayesian networks and case-based reasoning to create a knowledge representation scheme capable of dealing with time-varying processes. Static Bayesian network topologies are learned from previously available raw data and from sets of constraints describing significant events. These constraints are defined as sets of variables assuming significant values. As new data are gathered, dynamic changes to the topology of a Bayesian network are assimilated using techniques that combine single-value decomposition and minimum distance length. The new topologies are capable of forecasting the occurrences of significant events given specific conditions and monitoring changes over time. Since environment problems are good examples of temporal variations, the problem of forecasting ozone levels in Mexico City was used to test this framework. 相似文献
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Bayesian Networks have been proposed as an alternative to rule-based systems in domains with uncertainty. Applications in monitoring and control can benefit from this form of knowledge representation. Following the work of Chong and Walley, we explore the possibilities of Bayesian Networks in the Waste Water Treatment Plants (WWTP) monitoring and control domain. We show the advantages of modelling knowledge in such a domain by means of Bayesian networks, put forth new methods for knowledge acquisition, describe their applications to a real waste water treatment plant and comment on the results. We also show how a Bayesian Network learning environment was used in the process and which characteristics of data in the domain suggested new ways of representing knowledge in network form but with uncertainty representations formalisms other than probability. The results of applying a possibilistic extension of current learning methods are also shown and compared. 相似文献
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混合贝叶斯网络隐藏变量学习研究 总被引:6,自引:0,他引:6
目前,具有已知结构的隐藏变量学习主要针对具有离散变量的贝叶斯网和具有连续变量的高斯网.该文给出了具有连续和离散变量的混合贝叶斯网络隐藏变量学习方法.该方法不需要离散化连续变量,依据专业知识或贝叶斯网络道德图中Cliques的维数发现隐藏变量的位置,基于依赖结构(星形结构或先验结构)和Gibbs抽样确定隐藏变量的值,结合扩展的MDL标准和统计方法发现隐藏变量的最优维数.实验结果表明,这种方法能够有效地进行具有已知结构的混合贝叶斯网络隐藏变量学习. 相似文献