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提出了一种新的约束求解方法求解特征交互过程中两个特征形状在空间上发生重叠的约束。这个约束求解器在特征模型的参数空间进行取样的基础之上,利用蒙特卡罗技术来减少样本数据量。该方法不但可以产生一组正确的几何约束,而且提高了效率约束转换的效率。 相似文献
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基于笔式手势的自然交互是支持概念设计创新的有效方式.提出了一种笔式手势的层次概念模型,结合基于约束的自由勾画和上下文感知技术描述了手势设计方式,进一步讨论了手势内部的约束建立和求解算法;基于手势应用的范式,给出了概念设计中特征手势建模的应用实例,通过与传统建模和交互方式的对比,验证了特征手势建模的方便性.给出一个自然、高效的方法,以基于手势的方式来完成概念设计构思过程,采用笔式交互快速自然地记录下设计思路,所实现的系统方便了用户的创新设计,改善了人机交互模式. 相似文献
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针对智能航天器的在线自主规划问题,提出了一种基于活动模型的建模方法.该方法采用规划域定义语言(Planning Domain Definition Language, PDDL)对航天器的各个活动进行表示,最终建立航天器的规划领域模型.针对规划问题中资源约束和定性定量时间约束的表达问题,采用扩展基本活动模型的方法,通过对基本活动模型添加等式和不等式,最终解决了自主规划问题中的约束建模问题.最后以一类光学成像卫星为对象,建立了其自主规划模型并开发了相应的导引式求解算法.仿真结果表明,建模方法和算法是有效的. 相似文献
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针对当前对象族模型在求解拓扑约束时存在的缺陷,提出一种求解拓扑约束的新方法,这种方法在求解拓扑约束时,把拓扑约束映射为布尔约束满足问题,通过用SAT求解器求解布尔约束来求解拓扑约束。实践证明,该方法不仅直接关联与拓扑约束指定的特征的语义,而且当模型中存在大量相交的特征时也是可行的,提高了拓扑约束求解的效率。 相似文献
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实现了一种基于笔式草绘特征建模方法.该方法模仿传统的纸笔草绘交互设计方式,利用意图捕捉机制揣测用户的设计意图,并采用基于特征的建模方法构造出三维实体概念模型.支持在模型表面上直接草绘截面和轨迹线,并通过特征切削或添加操作构造复杂物体模型;初步实现了基于手势的模型编辑操作.实验结果表明,该方法简单、高效,适合于快速表达不精确的概念模型. 相似文献
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提出一种使用邻接矩阵保证最优交通小区划分一阶邻接约束的整数规划建模方法。从求解复杂度和质量两个角度,比较并分析了该邻接约束建模方法与其他3种方法对问题求解效率的影响。设计了聚合式层次聚类启发算法以求解所提出的模型。针对较大规模算例,将所提出的建模方法与其他3种邻接约束建模方法的结果进行了对比与分析。结果表明,基于邻接矩阵表示的建模方法能在允许时间内求得满意解,较其他3种方法更适合大规模问题。 相似文献
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Daniela Rabiser Herbert Prähofer Paul Grünbacher Michael Petruzelka Klaus Eder Florian Angerer Mario Kromoser Andreas Grimmer 《Software and Systems Modeling》2018,17(3):913-938
Feature models are frequently used to capture the knowledge about configurable software systems and product lines. However, feature modeling of large-scale systems is challenging as models are needed for diverse purposes. For instance, feature models can be used to reflect the perspectives of product management, technical solution architecture, or product configuration. Furthermore, models are required at different levels of granularity. Although numerous approaches and tools are available, it remains hard to define the purpose, scope, and granularity of feature models. This paper first reports results and experiences of an exploratory case study on developing feature models for two large-scale industrial automation software systems. We report results on the characteristics and modularity of the feature models, including metrics about model dependencies. Based on the findings from the study, we developed FORCE, a modeling language, and tool environment that extends an existing feature modeling approach to support models for different purposes and at multiple levels, including mappings to the code base. We demonstrate the expressiveness and extensibility of our approach by applying it to the well-known Pick and Place Unit example and an injection molding subsystem of an industrial product line. We further show how our approach supports consistency between different feature models. Our results and experiences show that considering the purpose and level of features is useful for modeling large-scale systems and that modeling dependencies between feature models is essential for developing a system-wide perspective. 相似文献
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Diego H. Milone Author Vitae Leandro E. Di Persia Author Vitae Author Vitae 《Pattern recognition》2010,43(4):1577-1589
Hidden Markov models have been found very useful for a wide range of applications in machine learning and pattern recognition. The wavelet transform has emerged as a new tool for signal and image analysis. Learning models for wavelet coefficients have been mainly based on fixed-length sequences, but real applications often require to model variable-length, very long or real-time sequences. In this paper, we propose a new learning architecture for sequences analyzed on short-term basis, but not assuming stationarity within each frame. Long-term dependencies will be modeled with a hidden Markov model which, in each internal state, will deal with the local dynamics in the wavelet domain, using a hidden Markov tree. The training algorithms for all the parameters in the composite model are developed using the expectation-maximization framework. This novel learning architecture could be useful for a wide range of applications. We detail two experiments with artificial and real data: model-based denoising and speech recognition. Denoising results indicate that the proposed model and learning algorithm are more effective than previous approaches based on isolated hidden Markov trees. In the case of the ‘Doppler’ benchmark sequence, with 1024 samples and additive white noise, the new method reduced the mean squared error from 1.0 to 0.0842. The proposed methods for feature extraction, modeling and learning, increased the phoneme recognition rates in 28.13%, with better convergence than models based on Gaussian mixtures. 相似文献
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特征模型作为捕获领域需求的重要模型已被现阶段的主流领域工程方法所接受,但这些方法缺乏对特征模型组织框架的细致研究和说明,在一定程度上导致了特征模型在表现形式上的冗余性和混乱性,也使得领域分析人员在实践中很难有效地进行领域建模活动.从特征模型的基本组织结构、变化性的表现方式和限制机制、变化性的绑定时间等方面对特征模型的组织框架及剪裁机制进行了统一、抽象的描述.在考察服务、用例(use case)、功能、行为特点等不同类型的特征及其相互关系的基础上,给出了一种特征模型的具体形式,并结合具体的领域,对其建模过程进行了详细论述.此项研究对于领域建模活动的成功实施具有一定的指导作用. 相似文献
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以网络为中心的协同特征造型 总被引:11,自引:1,他引:10
在网络化同步协同设计环境中,如何实现CAD系统之间的实时数据交换和模型同步,成为协同几何造型的关键问题。文中提出了一种新的复制式协同特征造型方法,该方法将现有的特征造型技术与分布计算、网络通信技术相结合,通过简单的造型消息交换来实现增量式协同造型,可以较好地满足几何模型实时同步的需要,而且也部分地解决了异构CAD软件之间的数据交换问题;并详细地介绍了协同造型通信协议、对象引用机制、以及分布式协同造型系统。 相似文献
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This paper introduces a new epsilon-insensitive fuzzy c-regression models (epsilonFCRM), that can be used in fuzzy modeling. To fit these regression models to real data, a weighted epsilon-insensitive loss function is used. The proposed method make it possible to exclude an intrinsic inconsistency of fuzzy modeling, where crisp loss function (usually quadratic) is used to match real data and the fuzzy model. The epsilon-insensitive fuzzy modeling is based on human thinking and learning. This method allows easy control of generalization ability and outliers robustness. This approach leads to c simultaneous quadratic programming problems with bound constraints and one linear equality constraint. To solve this problem, computationally efficient numerical method, called incremental learning, is proposed. Finally, examples are given to demonstrate the validity of introduced approach to fuzzy modeling. 相似文献
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基于实时组件的可重构数控系统研究 总被引:3,自引:0,他引:3
针对可重构数控系统存在的行为与定时问题,将调度机制引入基于口的组件,提出一种实时组件模型,并以此为基础建立了层次化多模式的数控系统体系结构。该结构通过层次化有限自动机描述系统的控制行为;通过组件网络刻画系统的定时特性,为分析可重构控制器构形的变化提供了有效的手段。针对2轴控制器的重构过程有效地验证了文中方法的有效性。 相似文献
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用户需求和运行环境的变化增加了软件产品开发、维护和演化的难度.另一方面,如果能对同类软件(比如软件产品家族)的变化性实施有效的控制,则可以极大地促进软件复用,提高软件生产效率和质量.对变化性建模是控制变化性的有效手段,既有助于变化性的识别和规约,又能够提供足够的机制支持变化性的演化.提出了一种面向产品家族的变化性建模方法,以变化性的管理策略为指导,从扩展的用况(use case)模型入手捕获系统行为的变化性,以特征模型来组织功能性需求和质量属性并识别其变化性,两种模型对变化性的建模采用相同的机制.还结合一个实例讨论了产品家族变化性建模的全过程.该研究对产品家族变化性的分析与建模具有一定的参考作用. 相似文献