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1.
Bayesian approach is an important method in statistics.The Bayesian belief network is a powerful knowledge representation and reasoning tool under the conditions of uncertainty.Paper,an approach to Bayesian network construction is given for discovering the Chinese Linguistic parameter relationship in the corpus.  相似文献   

2.
Urban traffic congestion propagation and bottleneck identification   总被引:2,自引:0,他引:2  
Bottlenecks in urban traffic network are sticking points in restricting network collectivity traffic efficiency. To identify network bottlenecks effectively is a foundational work for improving network traffic condition and preventing traffic congestion. In this paper, a congestion propagation model of urban network traffic is proposed based on the cell transmission model (CTM). The proposed model includes a link model, which describes flow propagation on links, and a node model, which represents link-to-link flow propagation. A new method of estimating average journey velocity (AJV) of both link and network is developed to identify network congestion bottlenecks. A numerical example is studied in Sioux Falls urban traffic network. The proposed model is employed in simulating network traffic propagation and congestion bottleneck identification under different traffic demands. The simulation results show that continual increase of traffic demand is an immediate factor in network congestion bottleneck emergence and increase as well as reducing network collectivity capability. Whether a particular link will become a bottleneck is mainly determined by its position in network, its traffic flow (attributed to different OD pairs) component, and network traffic demand.  相似文献   

3.
The next generation wireless network will be composed by various heterogenous wireless access networks,such as cellular network,worldwide interoperability for microwave access(WiMAX),wireless local area network(WLAN),etc.Different access networks cooperatively provide high-bandwidth connectivity with bandwidth guarantees.This paper proposes a utility-based access point selection scheme,which selects an accessible point for each user,such that the bandwidth requirement of each user is satisfied,and also the defined utility function is maximized.Due to the NP-complete nature of the problem,the existing proposals apply the greedy method to find a solution.We find that belief propagation is an efficient tool to solve this problem,and thus,we derive the same optimization objective in a new way,and then draw a factor graph representation which describes our combinatorial optimization problem.Afterwards,we develop the belief propagation algorithm,and show that our algorithm converges.Finally,we conduct numerical experiments to evaluate the convergency and accuracy of the belief propagation in load balancing problem.  相似文献   

4.
A system, method and article of manufacture are provided for conveying redundancies and omissions among components of a network framework such as a web architecture framework. First, an area of an existing network framework is determined in which redundancies and omissions exist. Next, a pictorial representation of the existing network framework is presented along with a plurality of its components. The foregoing redundancies and the omissions are then highlighted by indicia coding the components of the existing network that reside in the area. As such, a diagnostic analysis of redundant efforts and gaps in a current implementation of the existing network framework is effectively conveyed.  相似文献   

5.
Double-loop is a very popular structure in loop network topology.A reconfigurable bi-directional double-loop structure is recently developed.It has a new structure which is different from any existing double-loop structure and no previous methods can be used to evaluate its fault tolerance which is demanded for all fresh ideas.This paper provides an easy approach to offset this deficiency.A network is segmented first based on its block connection and then analyzed in a recursive way The calculation using this method requires linear time and very small memory capacity.This method can be used in analyzing th fault tolerance of other topologically segmental loop networks.  相似文献   

6.
Research and Design of a Fuzzy Neural Expert System   总被引:2,自引:0,他引:2       下载免费PDF全文
We have developed a fuzzy neural expert system that has the precision and learning ability of a neural network.Knowledge is acquired from domain experts as fuzzy rules and membership functions.Then,they are converted into a neural network which implements fuzzy inference without rule matching.The neural network is applied to problem-solving and learns from the data obtained during operation to enhance the accuracy.The learning ability of the neural network makes it easy to modify the membership functions defined by domain experts.Also,by modifying the weights of neural networks adaptively,the problem of belief propagation in conventional expert systems can be solved easily.Converting the neural network back into fuzzy rules and membership functions helps explain the inner representation and operation of the neural network.  相似文献   

7.
The exponential growth of user traffic has been driving routers to run at higher capacity. In a traditional router, the centralized switching fabric is becoming the bottleneck for its limited number of ports and complicated scheduling algorithms. Direct networks, such as 3-D Torus topology, have been successfully applied to the design of scalable routers. They show good scalability and fault tolerance. Unfortunately, its scalability is limited in practice. In this paper, we introduce another type of direct network, called H-Torus. This network shows excellent topological properties. On its basis, the designs of line card and routing algorithms are introduced. Extensive simulations show that the routing algorithm is very important in such a system and results in low latency with high throughput.  相似文献   

8.
A practical interconnection network RP(k) and its routing algorithms   总被引:8,自引:0,他引:8  
Based on Petersen graph, a new interconnection network, the RP(k) network, is devel-oped and the properties of the RP(k) network are investigated. The diameter of the RP(k) network is [ k/2] + 2 and its degree is 5. We prove that the diameter of the RP(k) network is much smaller than that of the 2-D Torus network when the number of nodes in interconnection networks is less than or equal to 300. In order to analyze the communication performance in a group of nodes, we propose the concepts of the optimal node groups and the diameter of the optimal node groups. We also show that the diameter of the optimal node groups in the RP(k) network is less than that in the 2-D Torus net-work. Especially when the number of nodes in an optimal node group is between 6 and 100, the diam-eter of the optimal node groups in the RP(k) network is half of that in the 2-D Torus network. Further-more based on the RP(k) network we design a set of routing algorithms which are point-to-point rout-ing, permutation routing, one-to-al  相似文献   

9.
The TianHe-1A Supercomputer: Its Hardware and Software   总被引:4,自引:0,他引:4       下载免费PDF全文
This paper presents an overview of TianHe-1A (TH-1A) supercomputer, which is built by National University of Defense Technology of China (NUDT). TH-1A adopts a hybrid architecture by integrating CPUs and GPUs, and its interconnect network is a proprietary high-speed communication network. The theoretical peak performance of TH-1A is 4700 TFlops, and its LINPACK test result is 2566 TFlops. It was ranked the No. 1 on the TOP500 List released in November, 2010. TH-1A is now deployed in National Supercomputer Center in Tianjin and provides high performance computing services. TH-1A has played an important role in many applications, such as oil exploration, weather forecast, bio-medical research.  相似文献   

10.
11.
信度网中条件概率表的学习   总被引:6,自引:1,他引:5  
一、引言信度网B的学习包括结构B(?)的学习和条件概率表B_p的学习。因果马尔可夫条件原理表明:如果图形G是一个随机变量集合X的因果图,那么图形G也是该随机变量集合的联合概率分布所对应的信度网的结构图。根据这一原理,在实际应用中,可以利用领域  相似文献   

12.
在可控网络中,利用多agent系统是网络控制的一种重要方法.在可控网络中,多agent系统中所有agent持有的信念必须在决策前达到与网络实际状态一致,即多agent系统的信念应具有可达性,是实现网络合理控制的基础.传统的基于agent行为的信念更新模型建模过程复杂,不适合在网络控制中直接分析多agent系统信念的可达性和收敛速度.基于传统的信念更新模型,提出了信念距离的概念,并在该概念的基础上提出了新的多agent系统信念距离更新模型,并证明了该模型的合理性.该模型对多agent系统信念距离更新过程加以描述,利用线性系统对多agent系统信念收敛过程进行描述,简化了对多agent系统信念可达性和收敛速度分析的复杂性.在该模型基础上,对网络控制中多agent系统信念可达性和收敛速度进行了分析,给出了判断多agent系统信念可达性的充要条件和收敛速度的上限.另外,针对全耦合网络和无标度网络两种复杂网络的特点,分别对两种网络下多agent系统信念可达性和收敛速度进行了讨论.提出的信念距离更新模型具有良好的适应性,为判断多agent系统的信念可达性提供了有力的工具.  相似文献   

13.
Luo  Ji  Zhao  Chuhao  Chen  Qiao  Li  Guangqin 《The Journal of supercomputing》2022,78(1):379-405

To study the impact of the agricultural information system based on the Internet of Things (IoT) on the income of agricultural products, an agricultural information system was constructed based on the agricultural IoT technology, and its impact on the income of agricultural products was discussed through the deep belief network. First, the relevant theories of agricultural IoT were introduced. Then, an agricultural information system based on agricultural IoT technology was constructed, and a deep belief network model was proposed. The vegetable prices and influencing factors were collected. The data were distributed in the range of 0–1 after normalization. The collinearity between the data was eliminated through principal component analysis. Then, the principal component analysis of vegetable prices and influencing factors from 2015 to 2019 was performed. A total of 96 sample data of calibration set and 24 sample data of test machine were collected. The optimal number of hidden layers of the deep belief network model and the number of nodes contained in the hidden layer were obtained through experiments. The results show that the first, second, and third hidden layers have 8, 6, and 10 nodes, respectively; the prediction accuracy of the deep belief network model is more accurate than that of the BP neural network and wavelet neural network. Besides, the absolute value of the prediction error of the deep belief model is within 0.1, which has good prediction accuracy. In short, the deep belief model has a good development prospect in agricultural product price forecasting, and it can provide relevant reference for the establishment and research of other agricultural product price forecasting models.

  相似文献   

14.
Properties of Sensitivity Analysis of Bayesian Belief Networks   总被引:1,自引:0,他引:1  
The assessments for the various conditional probabilities of a Bayesian belief network inevitably are inaccurate, influencing the reliability of its output. By subjecting the network to a sensitivity analysis with respect to its conditional probabilities, the reliability of its output can be investigated. Unfortunately, straightforward sensitivity analysis of a belief network is highly time-consuming. In this paper, we show that by qualitative considerations several analyses can be identified as being uninformative as the conditional probabilities under study cannot affect the output. In addition, we show that the analyses that are informative comply with simple mathematical functions. More specifically, we show that a belief network's output can be expressed as a quotient of two functions that are linear in a conditional probability under study. These properties allow for considerably reducing the computational burden of sensitivity analysis of Bayesian belief networks.  相似文献   

15.
基于概率知识表达的信度网已成为人工智能中非确定知识表达和推理的研究热点。推理算法是信度网学习和应用的基础。该文提出了一种基于经典Polytree算法的推理计算模型。该模型表达清楚,计算过程容易控制,并能够简单地映射到并行机结构上。该文首先介绍了模型在单联通网络下的计算步骤,然后将模型引入到多联通网络上。  相似文献   

16.
深度信念网络(Deep Belief Networks,DBN)作为深度学习(Deep Learning,DL)中的重要模型,目前已被成功应用于人脸识别、手写字体识别、医学图像分析处理等诸多领域。从深度信念网络出发,主要做了四个方面的工作:第一,从受限玻尔兹曼机以及深度信念网络的网络结构和学习过程两个方面阐述了深度信念网络的基本原理;第二,从网络结构和学习算法两个方面总结了深度信念网络的研究进展:在网络结构方面,从网络深度、RBM结构和DBN级联三个角度进行归纳;在学习算法方面,从基本算法、优化算法和融合方法三个方面进行梳理;第三,对深度信念网络在医学图像分析领域中的应用进行了总结;第四,总结了目前DBN存在的问题。  相似文献   

17.
深度学习作为近年热门研究领域,具有极大的应用前景,但存在过拟合、欠拟合、隐藏层数和节点数选取等诸多问题。针对深度置信网络存在的过拟合问题,借鉴压缩感知理论和零范数的数学性质,构建了一种基于无均值高斯分布函数的稀疏深度置信网络。通过在预训练阶段添加稀疏正则项,进一步改进深度置信网络训练过程的方法加以解决过拟合问题。利用ORL和MINIST两种公开数据集上对该改进方案进行验证分析,结果表明其比现有的改进方案在稀疏性和准确性上有较大提升。  相似文献   

18.
随着汽车的使用量的增加,传统的平面停车场地已经不能满足人们的停车需求。立体车库通过使用垂直空间多层停放的立体解决方案,能够最大限度利用土地空间资源,它的研发与使用受到越来越多人的关注。设计了立体车库云端可视化故障诊断系统,采集底层立体车库智能控制机无线发送过来的车库运行历史和实时数据,存入相应的数据库中通过对车库运行的历史和实时数据进行研究。提出使用深度置信网络算法对数据进行故障诊断,介绍了该算法的原理及实现,并且通过Python验证了深度置信网络的有效性。  相似文献   

19.
使用智能代理进行网络设备的告警关联   总被引:4,自引:1,他引:3  
为了解决集中式网络故障管理固有的缺陷,提出了一种基于SNMP网络管理环境、使用分布式智能代理进行网络设备告警关联的算法,算法分成3步:①智能代理驻留在设备本地,对设备发出的告警进行分类,作为相应协议对象的故障模型FSM的输入,运行这个FSM产生该协议对象的当前状态;②按照关联关系的形式化定义,尝试对状态不正常的协议对象进行关联;③为了给关联的结果增加一个可信度的度量,计算关联结果的信念,将关联的结  相似文献   

20.
Providing explanations of the conclusions of decision-support systems can be viewed as presenting inference results in a manner that enhances the user's insight into how these results were obtained. The ability to explain inferences has been demonstrated to be an important factor in making medical decision-support systems acceptable for clinical use. Although many researchers in artificial intelligence have explored the automatic generation of explanations for decision-support systems based on symbolic reasoning, research in automated explanation of probabilistic results has been limited. We present the results of an evaluation study of INSITE, a program that explains the reasoning of decision-support systems based on Bayesian belief networks. In the domain of anesthesia, we compared subjects who had access to a belief network with explanations of the inference results to control subjects who used the same belief network without explanations. We show that, compared to control subjects, the explanation subjects demonstrated greater diagnostic accuracy, were more confident about their conclusions, were more critical of the belief network, and found the presentation of the inference results more clear.  相似文献   

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