共查询到20条相似文献，搜索用时 15 毫秒
1.
In this paper, a modified adaptive neural network for the compensation of deadzone is described, and simulated on a hydraulic positioning system, in which the dynamic model is separated into a series of connection of a nonlinear (deadzone) subsystem and a linear plant. The proposed approach uses two neural networks. One is the radial basis function (RBF) neural network, which is used for identifying parameters of deadzone. Based on the penalty function used in optimization theory, a multi-objective cost function with constraint is adopted to provide the best deadzone approximation. The result is used to train the other neural network for the inverse compensation of deadzone. The RBF neural network also generates the parameters of the linear plant for the design of an adaptive controller. A convergence analysis for the network training process is also presented. 相似文献
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R. Saeks 《Journal of The Franklin Institute》1976,302(4):331-355
In some recent work Kailath and Duttweiler used reproducing Kernel Hilbert space techniques, together with a highly non-standard time structure, to formulate a representation theory for stochastic processes. Although non-standard their structure satisfied the axioms for a resolution space; a Hilbert space to which a time structure is axiomatically adjoined which has received considerable interest in the mathematical system theory literature.In the present paper the work of Kailath and Duttweiler is extended via the concept of a reproducing kernel resolution space which is defined for the covariance of an arbitrary resolution space valued random variable. Applications to the representation and approximation of stochastic processes are considered, a new formula for the optimal stochastic predictor is derived, and a canonical form for the causal factors of an arbitrary covariance is obtained. 相似文献
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采用Norton模型对产品更新换代扩散趋势的研究——以中国互联网用户上网方式的更新换代为例 总被引：2，自引：0，他引：2
本文在Bass模型的基础上,详细介绍了产品更新换代扩散的Norton模型,并例举了通信产业的产品更新换代扩散的实例,中国互联网上网方式的更新换代的发展。模型参数的估算是影响模型准确性的一个重要方面,论文总结了前人的成果,采用遗传算法作为Norton模型的参数估计方法,并对中国互联网的上网方式,如拨号上网、ISDN(综合业务数字网)上网、宽带上网的扩散进行实证研究,模型得出另人满意的结果,并将结果与Bass模型进行了比较和讨论,得出结论,采用Norton模型研究产品更新换代扩散是一种更好的选择。最后,论文对中国移动通信网络发展提出展望。 相似文献
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《Journal of The Franklin Institute》2022,359(5):2229-2243
This paper studies the verification of multi-potential games with a given partition, and proposes a kind of multi-potential equation based on semi-tensor product of matrices. Firstly, the basis of each player’s potential function is constructed, based on which, a new formula is established for the calculation of each player’s potential function. Secondly, a new potential equation is proposed for the verification of potential games via each player’s potential function. Using the new potential equation, a kind of multi-potential equation is constructed for the verification of multi-potential games with a given partition. It is proved that a finite game is a multi-potential game with a given partition if and only if the multi-potential equation has solution. In addition, all possible potential functions are obtained for each group of the partition. An illustrative example is worked out to show the effectiveness of the obtained new results. 相似文献
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《Information processing & management》2023,60(1):103088
Linear equations are valuable for real-world modeling phenomena involving at least one variable. However, verifying if the procedure followed by a human for solving a linear equation was done correctly is still a complicated matter. In this paper, we propose a methodology for the automatic character recognition and revision of the solving procedure of linear equations with one unknown. First, a camera is used to acquire an image of the handwritten solving procedure. Then, the image is pre-processed, and each character and equation lines are segmented. Subsequently, a convolutional neural network (CNN) is used to conduct the character recognition stage. Finally, a comparison rule is applied to revise the solving procedure. The character recognition was verified on a 2800 image data set (2100 for training and 700 for testing), including the ten digits and four symbols: ×, +, -, /. The revision procedure was tested on a data set with 140 handwritten equations (125 for training and 15 for testing). The results revealed that we recognized handwritten characters with an accuracy of 99%, which is similar to the state-of-the-art. Moreover, our proposal revised the solving procedure with an efficiency of 86.66%. 相似文献
7.
Annemarie Jutel 《Endeavour》2021,45(1-2):100764
One common contemporary usage of the term “diagnostic uncertainty” is to refer to cases for which a diagnosis is not, or cannot, be applied to the presenting case. This is a paradoxical usage, as the absence of diagnosis is often as close to a certainty as can be a human judgement. What makes this sociologically interesting is that it represents an “epistemic defence,” or a means of accounting for a failure of medicine’s explanatory system. This system is based on diagnosis, or the classification of individual complaints into recognizable diagnostic categories. Diagnosis is pivotal to medicine’s epistemic setting, for it purports to explain illness via diagnosis, and yet is not always able to do so. This essay reviews this paradoxical use, and juxtaposes it to historical explanations for non-diagnosable illnesses. It demonstrates how representing non-diagnosis as uncertainty protects the epistemic setting by positioning the failure to locate a diagnosis in the individual, rather than in the medical paradigm. 相似文献
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中国经济发展面临重大调整 总被引：3，自引：0，他引：3
自主创新是行动,是一个需要长期坚持的国策,是要持之以恒的一种战略选择,是一个地区长期坚持的过程。提高企业自主创新能力是我国经济发展阶段的客观要求,也是科学技术实现支撑国民社会发展和引领国民发展的战略机遇,把握这样的机会来提高中国的自主创新能力对于中国的未来具有极其重要的战略意义。 相似文献
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高等院校最中心的工作是教学工作,离开教学工作一切成了空谈.而教学管理工作则是保障教学工作合理、有效运行的非常重要的工作,它的好坏决定了高校教学的成功与否,因此,推进高校教学管理科学化则成为了广大高校管理工作者普遍关心的问题.本文探究了高校教学管理科学化的一系列举措,希望能给诸位同行一些启示. 相似文献
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考虑了一类非线性系统的局部镇定问题.首先,利用正则型理论给出一类 3阶非线性系统稳定的充分条件;然后利用得到的结果以及中心流形理论,讨论一类具有特殊形式的 3阶中心流形的非线性系统的镇定问题,并给出中心流形的设计方法以及镇定系统的控制律. 相似文献
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Optimal loan periods 总被引：1，自引：0，他引：1
Abraham Bookstein 《Information processing & management》1975,11(8-12)
The influence of a library's loan period on user satisfaction is a topic of considerable current interest. In this paper a model is created that is useful for studying this interaction. A policy, possibly appropriate for a reserve book room, is assumed, in which no queues form. Users not able to take out a book either give up or return. Also, the model includes the effect of a patron not being able to use a book for a sufficient length of time. This model yields equations for the value of the loan period that minimizes the number of transactions at the circulation desk consistent with a constant level of real demand. An iterative solution procedure is described and its convergence proven. Other objective functions, and in particular, the probability of a user successfully using a book, are considered.The objective of the paper is not to detail an operating procedure for circulation systems, but to continue the discussion initiated by Philip Morse about how such systems can be modelled. Morse introduces a queuing model for circulating books, but neglects to consider the impact of queue formation on the arrival rate to the system. The intention of this paper is to emphasize the necessity of introducing such considerations and to indicate how such complications can be analytically treated. The specific system modelled is a simplified one, similar to the one discussed by Bruce in a recent article published in L.Q. This model, or variants adapted to local conditions should be useful in assisting decision-making regarding circulation, but it is the modelling process rather than the management aspect that is addressed by this paper. 相似文献
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Five hundred million tweets are posted daily, making Twitter a major social media platform from which topical information on events can be extracted. These events are represented by three main dimensions: time, location and entity-related information. The focus of this paper is location, which is an essential dimension for geo-spatial applications, either when helping rescue operations during a disaster or when used for contextual recommendations. While the first type of application needs high recall, the second is more precision-oriented. This paper studies the recall/precision trade-off, combining different methods to extract locations. In the context of short posts, applying tools that have been developed for natural language is not sufficient given the nature of tweets which are generally too short to be linguistically correct. Also bearing in mind the high number of posts that need to be handled, we hypothesize that predicting whether a post contains a location or not could make the location extractors more focused and thus more effective. We introduce a model to predict whether a tweet contains a location or not and show that location prediction is a useful pre-processing step for location extraction. We define a number of new tweet features and we conduct an intensive evaluation. Our findings are that (1) combining existing location extraction tools is effective for precision-oriented or recall-oriented results, (2) enriching tweet representation is effective for predicting whether a tweet contains a location or not, (3) words appearing in a geography gazetteer and the occurrence of a preposition just before a proper noun are the two most important features for predicting the occurrence of a location in tweets, and (4) the accuracy of location extraction improves when it is possible to predict that there is a location in a tweet. 相似文献
13.
京剧的唱腔是塑造人物形象的主要艺术手段,它是由不同类型的声腔和板式,结合人物性格,戏剧冲突,唱词内容和语言特点来设计的。京剧的腔体主要分西皮、二黄两大腔系,合称皮黄腔。板式颇多,一段唱腔运用什么板式或几种板式,是根据剧情发展和人物感情变化及唱词内容等设计的,是一种综合运用。 相似文献
14.
本研究以计划行为理论、"心物场"理论为基础,构建大学生网络舆论行为理论模型,并以厦门大学为例进行实证调研,分析影响大学生网络舆论行为的主要因素,揭示各因素之间的因果关系。结果显示:网络舆论行为态度对网络舆论行为意向的直接影响为0.03,T值为0.28,直接影响效果较小,且统计不显著;网络舆论行为评估对网络舆论行为意向的直接影响为0.31,T值为5.40,直接影响效果较大,且统计显著;网络舆论行为主观规范对网络舆论行为意向的直接影响为-0.08,T值为-0.87,直接影响较小,且统计不显著;网络舆论行为意向对网络舆论行为的直接影响为0.61,T值为8.74,直接影响非常大,且统计显著;新媒体场对网络舆论行为的直接影响为-0.23,方向为负,T值为-5.16,统计显著。研究结果对于加强高校大学生网络舆论的引导与控制具有积极的意义。 相似文献
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本文为设计学类专业计算机辅助设计课程改革提供了一个新的思路,建设设计学类专业计算机辅助设计平台课是一个复杂的系统工程,经过系统研究与实践,构建了平台课的设计方案。平台课的建设对于探索普通高等院校设计学科专业课程建设具有一定的借鉴与启发意义。 相似文献
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学科服务是国际图书馆界的一种先进的办馆理念和全新服务模式。随着用户信息需求、信息环境的变化以及图书馆自身发展的要求,图书馆实行学科服务是一个长期的趋势。通过湖北省高校图书馆学科服务的调研分析,认为学科团队是适合我国高校图书馆发展现状的学科服务模式。 相似文献
18.
Link mechanisms designed for time-dependent output on the assumption of uniform input velocity will not perform satisfactorily due to fluctuation of input velocity under the actual working conditions. Synthesis, taking the input velocity fluctuations into consideration, is very difficult. Incorporation of a flexible element between the input link and the drive-motor makes the synthesis very easy. Also, a mechanism used as a timing device, for example the one used for actuating a valve at specified timings, is subjected to pulse loading. A slider-crank mechanism subjected to such a pulse loading and flexibly coupled to a drive-motor is synthesized for position coordination in the present paper. A numerical example is included. 相似文献
19.
Joe Hong Chow 《Journal of The Franklin Institute》1978,305(5):275-281
Sufficient conditions are obtained to guarantee the asymptotic stability of a class of non-linear singularly perturbed systems. A procedure for constructing a Lyapunov function for such a class of systems is given, and a clearly defined domain of attraction of the equilibrium is obtained. A stabilizing feedback control for such systems is also proposed. 相似文献
20.
《International Journal of Information Management》2014,34(4):489-516
It is important for manufacturing companies to provide a standard for product data exchange between diverse computer systems. Past attempts to develop neutral format standards for data exchange have had limited success, and have led to the development of STEP (Standard for the Exchange of Product) as a data exchange standard. The STEP standard makes it easier to integrate systems that process various product life-cycle functions, such as design, engineering, manufacturing, logistics support, and will help to facilitate concurrent engineering. The goal of this paper is to facilitate the computer-readable exchange of the product bill of materials (BOM) information for product data management (PDM). In this paper, the STEP ISO 10303-21 is implemented to share the product data information in a manufacturing environment. A structural product bill of materials is first transformed into an Excel file format, then a PDM Schema Exporter is utilized to export a BOM Excel file to a STEP Part 21 file. A C# program decodes the STEP file into BOM information to update the PDM databases in SQL server for product data management. Also, SAS code is written to generate the indented bill of materials from the BOM information, to draw a tree diagram to present an accurate structural view of a product, and to export to PDM databases for product data structural view. 相似文献