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1.
Liu  Ying  Wang  Yifei  Chen  Long  Zhao  Jun  Wang  Wei  Liu  Quanli 《Artificial Intelligence Review》2021,54(5):3517-3537
Artificial Intelligence Review - Broad learning system (BLS) is viewed as a class of neural networks with a broad structure, which exhibits an efficient training process through incremental...  相似文献   

2.
This paper presents a Bayesian method for computing the probability of a Bayesian belief-network structure from a database. In particular, the paper focuses on computing the probability of a belief-network structure that contains a hidden (latent) variable. A hidden variable represents a postulated entity that has not been directly measured. After reviewing related techniques, which previously were reported, this paper presents a new, more efficient method for handling hidden variables in belief networks.  相似文献   

3.
Bayesian networks are a powerful approach for representing and reasoning under conditions of uncertainty. Many researchers aim to find good algorithms for learning Bayesian networks from data. And the heuristic search algorithm is one of the most effective algorithms. Because the number of possible structures grows exponentially with the number of variables, learning the model structure from data by considering all possible structures exhaustively is infeasible. PSO (particle swarm optimization), a powerful optimal heuristic search algorithm, has been applied in various fields. Unfortunately, the classical PSO algorithm only operates in continuous and real-valued space, and the problem of Bayesian networks learning is in discrete space. In this paper, two modifications of updating rules for velocity and position are introduced and a Bayesian networks learning based on binary PSO is proposed. Experimental results show that it is more efficient because only fewer generations are needed to obtain optimal Bayesian networks structures. In the comparison, this method outperforms other heuristic methods such as GA (genetic algorithm) and classical binary PSO.  相似文献   

4.
提出一种基于周期信号的迭代学习控制方法,并将其应用于电力逆变器,分析了跟踪误差沿迭代方向的收敛条件,给出了控制律的时域表达形式以及参数的确定方法.由于该方法理论上可实现跟踪误差收敛到零,因而使逆变器输出电压跟踪精度大幅提高.通过MATLAB/Simulink仿真,该方法的有效性得到验证;此外,与传统PID控制相比,仿真结果显示出该方法具有较好的负载适应能力以及优越的跟踪性能.  相似文献   

5.
简述了移动电子商务的基本概念和RFID技术应用的基本原理,分析了RFID手机在移动电子商务中的应用前景和制约因素,并提出了相关的参考建议。  相似文献   

6.
In a graph theory model, clustering is the process of division of vertices into groups, with a higher density of edges within groups than between them. In this paper, we introduce a new clustering method for detecting such groups and use it to analyse some classic social networks. The new method has two distinguished features: non-binary hierarchical tree and the feature of overlapping clustering. A non-binary hierarchical tree is much smaller than the binary-trees constructed by most traditional methods and, therefore, it clearly highlights meaningful clusters which significantly reduces further manual efforts for cluster selections. The present method is tested by several bench mark data sets for which the community structure was known beforehand and the results indicate that it is a sensitive and accurate method for extracting community structure from social networks.  相似文献   

7.
随着移动网络的迅速发展,越来越多的用户选择使用代理应用,以保护个人网络隐私,隐藏上网行为或绕开网络活动限制,给网络管理与审计带来了新的挑战。与此同时,恶意攻击者可利用代理应用隐藏身份,使得恶意行为更难以检测和防范。因此,代理应用流量识别对网络管理与安全具有重要的作用,但目前该问题并未得到充分的研究。由于代理应用流量通常经过加密或混淆处理,传统的流量识别技术无法被有效应用。为实现准确、快速的移动代理应用流量识别,提出一组与负载无关的流量特征,并首次加入TCP层option字段用于刻画流量。基于4种机器学习算法训练的分类器和2种流量识别对象,验证提出的特征对识别移动代理应用流量的有效性,并对各类特征的重要性进行分析。实验结果表明,提出的特征能有效识别代理应用流量。在识别流量是否经由代理时,基于随机森林的分类器可达到99%以上的整体准确率。识别流量所属代理应用时,整体准确率高于94%。在公开数据集ISCX VPN-nonVPN上与其他方法相比,提出的方法识别准确率更高,并具有更快的识别速度,适合实时流量识别场景。  相似文献   

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9.
Internet auctions bring buyers and sellers together for the purpose of trading goods and services online. In order to get the goods, a buyer must search for items through several auction sites. When the auction starts, the buyer needs to connect to these auction sites frequently so that he/she can monitor the bid states and re-bid. In this paper, we propose an automated negotiation model between two participants, for mobile commerce, using collaborative mobile agents called MoRVAM, which mediates between the buyer and the sellers, and executes bidding asynchronously and autonomously. A new RVT protocol is also implemented to achieve unconditional bid privacy. Advantages of the RVT protocol are addressed as well. All the bidding process can be implemented without revealing losing bid and unnecessary information.  相似文献   

10.
We uncovered two critical issues in earlier studies: (a) some studies have shown that mobile learning technology is not beneficial for all students due to complexity of learning environments and student prior knowledge, skills, and experience and (b) familiarity of students with the authentic environments in which they learn using mobile technology did not receive much attention in earlier studies. To address these issues, we designed three learning tasks for a class of 26 junior high school students. The students applied language skills by completing the tasks in authentic environments individually in a first task, loosely collaborating with peers in a second task, and tightly collaborating with peers in a third task. A mobile learning system was also designed in this study to support students to accomplish the tasks. The aim of this study was to explore students' learning experiences using the learning system, their perceptions towards the system, and to assess how differently the students perform on the three tasks. According to our design, in the first task, the students took pictures of objects and described them orally or in writing using the mobile learning system. In the second task, after the students completed assignments, each student received comments from a partner through the system. In comments, the partner indicated flaws in student assignments and suggested how to fix them. In the third task, the students completed assignments, shared them using the system, and then exchanged comments with their partners face to face regarding issues related to their completed assignments and suggested how to improve them. Such learning behaviours in the three tasks enabled the students to practise writing and speaking skills. Our results demonstrate that most of the students highly valued our learning system and intend to use it in the future. Furthermore, the results show that the students performed best when they collaborated; namely, student performance was enhanced the most after the third task that required tight collaboration. Based on our results, we learned that students' familiarity with authentic environments is very important and beneficial for their learning. In addition, we learned that even in complex environment, less skilled and experienced students with low prior knowledge can perform well when they tightly collaborate with more skilled and experienced students with high prior knowledge, and our learning system can facilitate such collaboration.  相似文献   

11.
基于机器学习的移动自组织网络入侵检测方法   总被引:1,自引:0,他引:1  
杨德明  潘进  赵爽 《计算机应用》2005,25(11):2557-2558
移动自组织网络是由无线移动节点组成的复杂分布式通信系统。研究了移动自组织网络的入侵检测问题,采用了一种新型的基于机器学习算法的异常入侵检测方法。该方法获取正常事件的内部特征的相互关系模式,并将该模式作为轮廓检测异常事件。在Ad hoc 按需距离向量协议上实现了该方法,并在网络仿真软件QualNet中对其进行了评估。  相似文献   

12.
A mobile learning system for scaffolding bird watching learning   总被引:4,自引:0,他引:4  
Abstract This paper develops a mobile learning system for scaffolding students learning about bird-watching. The aim is to construct an outdoor mobile-learning activity using up-to-date wireless technology. The proposed Bird-Watching Learning (BWL) system is designed using a wireless mobile ad-hoc network. In the BWL system, each learner has a PDA (Personal Digital Assistant) with a Wi-Fi-based (IEEE 802.11b) wireless network card. The BWL system offers a mobile learning system which supports the students learning through scaffolding. The aim of a formative evaluation was twofold: to explore the possible roles and scaffolding aids that the mobile learning device offers for bird-watching activities and to investigate whether student learning benefited from the mobility, portability, and individualisation of the mobile learning device.  相似文献   

13.
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15.
Surface precipitation estimation is very important in hydrologic forecast. To account for the influence of the neighbors on the precipitation of an arbitrary grid in the network, Bayesian networks and Markov random field were adopted to estimate surface precipitation. Spherical coordinates and the expectation-maximization (EM) algorithm were used for region interpolation, and for estimation of the precipitation of arbitrary point in the region. Surface precipitation estimation of seven precipitation station...  相似文献   

16.
To get the items that a buyer wants in an Internet auction, he must search for the items through several auction sites. When the bidding starts, the buyer needs to connect to these auction sites frequently so that he can monitor the bid states and re-bid. A reserve-price auction reduces the number of connections, but this limits the user's bidding strategy. Another problem is equity between the buyer and the seller. Both the buyer and the seller should profit within proper limits. In this paper, we propose an auction agent system using a collaborative mobile agent and a brokering mechanism called MoCAAS (Mobile collaborative auction agent system), which mediates between the buyer and the seller and executes bidding asynchronously and autonomously. This reduces the network load more than with other auction-agents, offers more intelligent bidding, and increases the clear ratio.  相似文献   

17.
During the past few years, a variety of methods have been developed for learning probabilistic networks from data, among which the heuristic single link forward or backward searches are widely adopted to reduce the search space. A major drawback of these search heuristics is that they can not guarantee to converge to the right networks even if a sufficiently large data set is available. This motivates us to explore an algorithm that will not suffer from this problem. We first identify an asymptotic property of different score metrics, based on which we then present a hybrid learning method that can be proved to be asymptotically convergent. We show that the algorithm, when employing the information criterion and the Bayesian metric, guarantees to converge in a very general way and is computationally feasible. Evaluation of the algorithm with simulated data is given to demonstrate the capability of the algorithm  相似文献   

18.
以移动教育方面的三方应用场景为例,设计并实现了一个面向精品课程和开放课程的移动学习系统原型,实现了网络教学资源整合。根据现行主流移动智能终端的特点,针对触摸屏移动智能终端因误操作引起的计算资源和通信资源浪费现象,给出了一个有三方参与的应用系统场景中,可行的减少误操作的应用方法。通过使用确定型有限自动机的方法验证了系统的正确性。测试表明,该方法可以有效降低应用场景中代理服务模块和资源服务模块的工作压力,提高用户体验度。  相似文献   

19.
为满足企业对移动商务系统的使用需求,对常用ERP系统的数据库和常用移动通信平台的SDK进行分析,在此基础上设计了能够将企业现有ERP系统与移动通信平台集成起来实现移动商务管理的系统。设计了系统架构,将系统分为3层,每层都采用插件技术;根据系统架构设计系统功能,将系统分为7个功能模块,通过这7个功能模块实现该系统的功能;最后设计系统编码,将编码从左到右分为5段,每段有不同的意义和格式要求。  相似文献   

20.
This paper aims to investigate how a gamified learning approach influences science learning, achievement and motivation, through a context‐aware mobile learning environment, and explains the effects on motivation and student learning. A series of gamified learning activities, based on MGLS (Mobile Gamification Learning System), was developed and implemented in an elementary school science curriculum to improve student motivation and to help students engage more actively in their learning activities. The responses to our questionnaire indicate that students valued the outdoor learning activities made possible by the use of a smartphone and its functions. Pre‐ and post‐test results demonstrated that incorporating mobile and gamification technologies into a botanical learning process could achieve a better learning performance and a higher degree of motivation than either non‐gamified mobile learning or traditional instruction. Further, they revealed a positive relationship between learning achievement and motivation. The correlation coefficient for ARCS dimensions and post‐test shows that the ARCS‐A (attention) is greater than ARCS‐R, ARCS‐C and ARCS‐S. This means that the attention (ARCS‐A) of this system is an important dimension in this research. The results could provide parents, teachers and educational organizations with the necessary data to make more relevant educational decision.  相似文献   

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