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本文形式化地提出了一种适用于多媒体对象的概念模型OMCOM.文中首先分析了多媒体数据模拟的特殊性,探讨了现有的多媒体数据模型的不足.从而提出了把多媒体数据模拟划分为概念与表达两级模拟的思想.概念级模拟多媒体对象的内容与结构;表达级模拟其表达,包括多媒体对象之间的时态关系和空间关系.OMCOM就是一种用于实现概念级模拟的模型.然后根据多媒体概念模拟的需求,形式化地定义了OMCOM的各个构成要素.最后根据OMCOM实例的格性质,建立了多媒体对象在概念级的运算体系——对象代数,形式化地定义了其中的各种运算以及对象代数表达式. 相似文献
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约束概念格及其构造方法 总被引:5,自引:0,他引:5
概念格是一种有效的数据分析和知识提取的形式化工具.然而,随着要处理的数据量的剧增,基于原始形式背景构造出的概念格结点数目庞大,占用大的存储空间,同时概念格结点中一些属性集形成的内涵,用户并不都感兴趣,因而从中提取用户需求知识费时.为了降低概念格构造的时空复杂性,增强实用性和针对性,首先采用谓词逻辑描述用户感兴趣的背景知识,并将背景知识引入到概念格结构中,提出了一种新的概念格:约束概念格.在此基础上,提出了基于背景知识的约束概念格构造算法CCLA.理论分析表明,该算法能有效地减少概念格的存储空间和建格时间.最后,采用恒星天体光谱数据作为形式背景,实验验证了该算法的有效性. 相似文献
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在数据库中自动发现广义序贯模式 总被引:11,自引:2,他引:9
本文将序贯模式的发现从单层(SingleLevel)概念扩展到多层(MultipleLevel)概念.即既允许在同层概念之间,也允许在不同层概念之间发现序贯模式,提出了发现广义序贯模式的自顶向下逐层递进的方法. 相似文献
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旋转动力学理论是以辨证思维和心理学理论为指导,微分拓扑为工具建立起来的创新计算的统一理论框架.本文探讨它的概念形成问题,包括概念表示,概念形成的基本方法及其语义.着重指出变异和组合是概念形成的基本途径,可演绎出任何新概念来.最后给出了理论的应用范例. 相似文献
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Web 2.0方兴未艾.Enterprise 2.0的概念又接踵而至,Enterprise 2.0讲述的是如何将Web 2.0与SOA结合.并应用于企业当中。在Enterprise 2.0概念提出之时,已经存在基于Web2.0和SOA的开源应用了.在这波浪潮中,开源技术又走在了前面。 相似文献
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Nilsson教授首先提出了代数格应用于概念知识表示的思想.其优点在于知识表示的代数特性和图示特性,在此基础上.表文把代数格与PROLOG相结合.定义了一种基于概念的逻辑编程语言.其语言具有比PROLOG更抽象、更方便的编程风格.此外.给出了该逻辑编程语言的匹配算法. 相似文献
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基于互关联后继树的概念格构造算法 总被引:7,自引:2,他引:7
概念格是知识工程中一个重要的知识表达工具,同时也是形式概念分析的核心.目前已出现了许多有效的概念格构造算法.提出了一个基于互关联后继树的概念格构造算法,以扩展的互关联后继树为数据模型,通过对树的搜索和相关判定定理完成所有形式概念的生成.分析了算法的性能,并做出相关结论. 相似文献
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《Calphad》2019
An excess Gibbs energy model describing the properties of aqueous electrolyte solutions, mixed solvent electrolyte systems and nonelectrolyte systems, has been developed. The suggested electrolyte version of the Generalized Local Composition Model (eGLCM) contains three contributions to the excess Gibbs energy: a long–range electrostatic interaction term represented by the modified Pitzer-Debye-Hückel equation, which takes into account concentration dependence of the solution dielectric permittivity, the contribution of the short–range interaction between all the species, represented by the GLCM model, and the middle–range interaction term responsible for interactions involving charged species that are not explained by the long–range term. The developed model is applicable over a whole concentration range, from pure water to saturation and fused salts. The water – nitric acid system, 15 water – rare earth element nitrate systems (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and eight water – nitric acid – REE nitrate systems (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) have been modeled with the proposed electrolyte version of the Generalized Local Composition Model at 25 °C, using experimental data on both the vapor – liquid (VLE) and solid – liquid (SLE) equilibria, in a concentration range from dilute solutions to saturation. SLE data in the ternary systems were critically reviewed and correlated with the thermodynamic properties of the solutions. 相似文献
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Abstract Education is a gradual process with long‐term goals, the achievement of which depends on the cumulative effects of an array of short‐ and long‐term educational experiences, with immediate and delayed effects. The reality is, however, that activities within educational systems tend to be oriented towards the short term. Furthermore, reviews of the research literature have shown repeatedly that longitudinal studies are scarce, and hence the research base for educational activities that aim at the long‐term is insufficient. The present article illustrates complexities that emerge when studies of learning and retention in school contexts, as well as of other educational processes, proceed along the time dimension. It makes methodological comments on alternative modes of studying change over time and advocates long‐term longitudinal studies. 相似文献
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Zhaolin Yuan Xiaorui Li Di Wu Xiaojuan Ban Nai-Qi Wu Hong-Ning Dai Hao Wang 《IEEE/CAA Journal of Automatica Sinica》2022,9(4):686-698
It is crucial to predict the outputs of a thickening system, including the underflow concentration (UC) and mud pressure, for optimal control of the process. The proliferation of industrial sensors and the availability of thickening-system data make this possible. However, the unique properties of thickening systems, such as the non-linearities, long-time delays, partially observed data, and continuous time evolution pose challenges on building data-driven predictive models. To address the above challenges, we establish an integrated, deep-learning, continuous time network structure that consists of a sequential encoder, a state decoder, and a derivative module to learn the deterministic state space model from thickening systems. Using a case study, we examine our methods with a tailing thickener manufactured by the FLSmidth installed with massive sensors and obtain extensive experimental results. The results demonstrate that the proposed continuous-time model with the sequential encoder achieves better prediction performances than the existing discrete-time models and reduces the negative effects from long time delays by extracting features from historical system trajectories. The proposed method also demonstrates outstanding performances for both short and long term prediction tasks with the two proposed derivative types. 相似文献
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人口经济动力学与CGE模型仿真 总被引:4,自引:0,他引:4
用通用数学建模系统软件GAMS建立了一个可以用于中长期预测和政策模拟的可计算一般均衡(CGE)模型系统.本系统由人口增长模型、生产模型和消费与储蓄模型组成.利用各个模型间的综合平衡关系和模型的动态反馈结构,将人口增长模型的输出作为外生变量,工资替代率和退休年龄作为控制变量,研究了按照中国人口老龄化的速度和依然运行传统的社会保障体系将会给国民经济和人民生活水平带来的影响,并探索了现有养老金系统改革可能达到的经济与社会效益. 相似文献
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Conceptual reservoir-type models of river systems, that mimic the results of detailed hydrodynamic models, provide a powerful tool for numerous river management applications. Thanks to their computationally efficient model structure they are very well suited for applications that require long term simulations or a large number of model iterations. However, one well-known problem is that conceptual models have difficulties to account for backwater effects. For this reason, their application to tidally influenced river reaches so far was almost non-existent. This paper introduces an extension of an existing grey-box reservoir modelling technique to incorporate tidally influenced river reaches. The methodology is demonstrated for the downstream part of the rivers Zenne and Rupel in Belgium. Results show a minor loss of accuracy when the detailed model is replaced by the surrogate conceptual model. Also, the tidal effects are well represented. 相似文献
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Whereas the benefits of decomposing process models are obvious, the question what actually characterizes a ??good?? decomposition of a business process model has been given little attention to date. In addition, the process of decomposition itself is considered as being an ??art?? in literature. Our approach for achieving a ??good?? decomposition is Wand and Weber??s decomposition model for information systems. As a first step in our investigation we aim to explore in how far the decomposition model can be adapted for business process modelling at all. The potential this model might bear for evaluating decompositions of process models has been promoted in literature quite often, while a corresponding investigation is still missing. We address this gap by the following research. In the long term, we intend to establish guidelines for decomposing business process models in a structured way. 相似文献
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Peer-to-peer(P2P) services heavily rely on users’ cooperation to achieve desired performance. However, most current P2P systems only encourage short-term and direct cooperation between peers. The lack of incentives for long term and indirect cooperation has severely limited the performance of P2P systems. On the other hand, recent measurements on large-scale networks show that peers’ behavior often demonstrates strong social patterns. In this paper, we design and implement a social P2P network, named SocialTrust, based on peers’ common interests. In SocialTrust, each peer tries to find a small number of friends and maintains long term social links with them. We also propose a distributed trust mechanism. The trust between two friends reflects their cooperation level and serves as the credit limit between them. A peer with higher trust can download data from its friends more efficiently. The trust can be propagated among friends to support indirect reciprocity. We formally prove that the proposed distributed trust mechanism is secure and can defend against various forms of attacks. By adding asmall number of long term social links to the existing P2P network, SocialTrust relaxes the constraint of direct incentive mechanisms and encourages peers to perform various forms of long-term cooperation. Both trace-driven simulation and real Internet experiments show that SocialTrust can significantly improve file availability and download performance of current P2P file sharing systems. 相似文献
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Cell therapy is a promising and emerging field for the treatment of human diseases. However, to understand and optimize cell
therapy, the inability to track the cell transplants in vivo remains a major problem. Most cell transplantation techniques
involve the use of histological analysis to evaluate cell transfection, proliferation, and migration after sacrifice. In this
literature, for the first time an in vivo model has been developed to study stem cells. Explantation culture of chicken embryo
into surrogate shells has been modified for high resolution and long term imaging. A special long distance fluorescence microscope
and micromanipulation systems has been developed for in vivo application specially aiming for the injection and tracking of
fluorescence labeled cells into chicken embryo and track them. By using the developed system, it was possible to image the
whole period of embryonic development of chicken embryo. 相似文献