Feature-based and objectoriented product information model for welding structure

Product information model for welding structure plays an important role for the integration of welding CAD/CAPP/CAM. However, existing CAD modeling systems are not capable of providing enough information for subsequent manufacturing activities such as CAPP and CAM. A new design approach using feature technique and object oriented programming method is put forward in this paper in order to create the product information model of welding structure. With this approach, the product information model is able to effectively support computer aided welding process planning, fixturing, assembling, path planning of welding robot and other manufacturing activities. The feature classification and representing scheme of welding structure are discussed. A prototype system is developed based on feature and object oriented programming. Its structure and functions are given in detail.

The Feature-Based a New Object Coding Approach for Prismatic Parts at the Part Modeling

Use of features in order to achieve the integration of design and manufacture has been considered to be a key factor recent years. Features such as manufacturing properties form the workpiece. Features are structured systematically through object oriented modeling. This article explains an object coding method developed for prismatic workpieces and the use of that method in process planning. Features have been determined and modeled as objects. Features have been coded according to their types and locations on the workpiece in this given method. Feature codings have been seen to be very advantageous in process planning.

Research on workflow meta model supporting activity based costing

Activity based costing (ABC) is a method which can solve many limitations of the traditional cost systems in manufacturing management. In this paper, we investigate how to integrate ABC with workflow technology, and build a workflow meta model supporting ABC. Firstly, the concept and concept model of activity based costing (ABC) are introduced. Next, the meta model of P -PROCE (Process, Product, Resource, Organization, and Cost & Evaluation) is presented. Then the cost meta model is defined by adding ABC to P -PROCE model. Object constraint language (OCL) is used to express meta model and constraints. Finally, we show an enterprise modeling and simulation tool based on the workflow meta model. We can systematically construct an enterprise model and easily and efficiently conduct simulation. Moreover it enables us to analyze and evaluate business processes and its costs.

High level architecture evolved modular federation object model

To improve the agility, dynamics, composability, reusability, and development efficiency restricted by monolithic federation object model （FOM）, a modular FOM is proposed by high level architecture （HLA） evolved product development group. This paper reviews the state-of-the-art of HLA evolved modular FOM. In particular, related concepts, the overall impact on HLA standards, extension principles, and merging processes are discussed. Also permitted and restricted combinations, and merging rules are provided, and the influence on HLA interface specification is given. The comparison between modular FOM and base object model （BOM） is performed to illustrate the importance of their combination. The applications of modular FOM are summarized. Finally, the significance to facilitate compoable simulation both in academia and practice is presented and future directions are pointed out.

Coach Simplified Structure Modeling and Optimization Study Based on the PBM Method

For the coach industry, rapid modeling and efficient optimization methods are desirable for structure modeling and optimization based on simplified structures, especially for use early in the concept phase and with capabilities of accurately expressing the mechanical properties of structure and with flexible section forms. However, the present dimension-based methods cannot easily meet these requirements. To achieve these goals, the property-based modeling （PBM） beam modeling method is studied based on the PBM theory and in conjunction with the characteristics of coach structure of taking beam as the main component. For a beam component of concrete length, its mechanical characteristics are primarily affected by the section properties. Four section parameters are adopted to describe the mechanical properties of a beam, including the section area, the principal moments of inertia about the two principal axles, and the torsion constant of the section. Based on the equivalent stiffness strategy, expressions for the above section parameters are derived, and the PBM beam element is implemented in HyperMesh software. A case is realized using this method, in which the structure of a passenger coach is simplified. The model precision is validated by comparing the basic performance of the total structure with that of the original structure, including the bending and torsion stiffness and the first-order bending and torsional modal frequencies. Sensitivity analysis is conducted to choose design variables. The optimal Latin hypercube experiment design is adopted to sample the test points, and polynomial response surfaces are used to fit these points. To improve the bending and torsion stiffness and the first-order torsional frequency and taking the allowable maximum stresses of the braking and left turning conditions as constraints, the multi-objective optimization of the structure is conducted using the NSGA-II genetic algorithm on the ISIGHT platform. The result of the Pareto solution set is acquired, and the selection strategy of the final solution is discussed. The case study demonstrates that the mechanical performances of the structure can be well-modeled and simulated by PBM beam. Because of the merits of fewer parameters and convenience of use, this method is suitable to be applied in the concept stage. Another merit is that the optimization results are the requirements for the mechanical performance of the beam section instead of those of the shape and dimensions, bringing flexibility to the succeeding design.

Extended Object Model for Product Configuration Design

This paper presents an extended object model for case-based reasoning （CBR） in product configuration design. In the extended object model, a few methods of knowledge expression are adopted, such as constraints, rules, objects, etc. On the basis of extended object model, case representation model for CBR is applied to product configuration design system. The product configuration knowledge can be represented by the extended object. The model can support all the processes of CBR in product configuration design, such as case representation, indexing, retrieving, and case revising. The presented model is an extension of the traditional object-oriented model by including the relationship class used to express the relation between the cases, constraints class used in the product configuration knowledge representation, index class used in ease retrieving, and solution class used in case revising. Therefore, the product configuration knowledge used in the product configuration design can be represented by using this model. In the end, a metering pump product configuration design system is developed on the basis of the proposed product configuration model to support customized products.

Ensemble Based Learning with Accurate Motion Contrast Detection

Recent developments in computer vision applications have enabled detection of significant visual objects in video streams.Studies quoted in literature have detected objects from video streams using Spatiotemporal Particle Swarm Optimization(SPSOM)and Incremental Deep Convolution Neural Networks(IDCNN)for detecting multiple objects.However,the study considered opticalflows resulting in assessing motion contrasts.Existing methods have issue with accuracy and error rates in motion contrast detection.Hence,the overall object detection performance is reduced significantly.Thus,consideration of object motions in videos efficiently is a critical issue to be solved.To overcome the above mentioned problems,this research work proposes a method involving ensemble approaches to and detect objects efficiently from video streams.This work uses a system modeled on swarm optimization and ensemble learning called Spatiotemporal Glowworm Swarm Optimization Model(SGSOM)for detecting multiple significant objects.A steady quality in motion contrasts is maintained in this work by using Chebyshev distance matrix.The proposed system achieves global optimization in its multiple object detection by exploiting spatial/temporal cues and local constraints.Its experimental results show that the proposed system scores 4.8%in Mean Absolute Error(MAE)while achieving 86%in accuracy,81.5%in precision,85%in recall and 81.6%in F-measure and thus proving its utility in detecting multiple objects.

基于BOM的光电信息控制仿真系统设计

为保证系统运行性能和模型复用性,应用基本对象模型(Basic Object Model,BOM)设计一种新型光电信息控制仿真系统。首先介绍BOM相关概念,其次,在完成系统仿真框架设计的基础上,从基本模型设计、组合模型设计、联邦成员和联邦设计3个方面入手,完成基于BOM系统的仿真模型设计。最后对系统进行实现。结果表明,所设计的基于BOM的光电信息控制仿真系统具有可维护性高、互操作性强及重用性高等特点,可有效地提高开发效率,完全符合预期设计标准和要求。

批判性思维在车辆工程专业课程教学中的运用——以汽车电器与电子课程为例

批判性思维是以一种以合理的、反思的、心灵开放的方式进行思考,从而能够清晰准确地表达、逻辑严谨地推理、合理地论证,进而完成思辨精神培养的思维方式。在车辆工程专业新工科人才培养的过程中,培养学生这种思维方式和精神,具有普适性意义,有利于新工科专业教育内涵发展。该文基于批判性思维教学方法的基本理论,结合汽车电器与电子课程教学实践,在教学目标设计、教学内容设计、议题式教学模式和课后辅导等方面,进行批判性思维在车辆工程专业课程教学中运用的探索,以培养具有学习能力的学生,进而满足汽车行业对于复合型人才的需要。

基于BOM动态测试框架的设计与实现

为基于基本对象模型(BOM)的仿真模型测试提供测试平台,提高模型可靠性,为仿真系统的集成提供可靠的仿真模型,缩短仿真系统集成联试的周期,设计了独立的模型测试平台,在测试平台中提供BOM模型运行所需要的对象管理、数据分发、时间管理等服务,通过仿真模型在平台中的运行结果分析,验证模型接口以及功能。模型测试平台可为各种类型的模型提供仿真运行环境,平台运行效率可达到超实时仿真要求,模型集成效率提高。在大规模作战仿真系统开发中,可推广使用模型测试平台,提高模型可靠性,降低集成成本,缩短集成周期。

基于BOM和FEDEP的多分辨率建模框架

为了规范和统一多分辨率模型的描述方法、建模步骤和活动,提出一种基于BOM(Base Object Model)和FEDEP(Federation Development and Execution Process)的多分辨率建模框架.该框架包括3种基于BOM的多分辨率建模方法和基于FEDEP的多分辨率建模过程.简要介绍这3种方法,重点分析FEDEP中与BOM和多分辨率建模相关的基本活动,将基于BOM的多分辨率建模过程与FEDEP集成在一起.该框架可以实现多分辨率模型描述的形式化和通用性、建模步骤和过程的规范化,促进多分辨率模型的重用、互操作和组合,保证模型的一致性和多分辨率建模的有效性.

利用XMI实现基于BOM的仿真模型组件的交换

BOM(Base Object Model)是快速构建仿真系统或联邦的可重用信息交互包,基于BOM的仿真模型组件是BOM信息描述的实现体,作为构建仿真系统或联邦的可重用模块。通过应用模型驱动体系结构(MDA,Model-Driven Architecture)提出的实现模型交换标准XMI(XML-based Metadata Interchange),HLA(HighLevel Architecture)仿真模型组件的建模和实现在两个不同层次上实现跨平台、跨语言和跨领域间的交换,而且HLA的重用性和互操作性思想能够在除分布式仿真领域外的其他应用领域中得到推广。

面向重用的BOM概念模型相似度评估研究

针对BOM概念模型重用的问题,提出了概念模型相似度用于描述两个概念模型之间的相似程度。并提出相似度评估算法用于计算概念模型之间的相似度。根据概念模型的定义,将相似度的计算归结为名字相似度计算和最优匹配计算两个基本过程。研究了算法中接口权重参数和行为权重参数的不同组合对算法查准率和查全率的影响。通过对JC3IEDM数据模型的测试,表明相似度能够正确反映概念模型的组成元素和结构的相似程度,算法可以正确计算出概念模型之间的相似度。算法在保证100%查全率的基础上,查准率大于75%。

基本对象模型(BOM)在HLA仿真系统中的应用

为了促进在世界范围政府部门和非政府部门的仿真互操作能力,仿真互操作标准组织(SISO)引进BOM支持和提高仿真组件的重用性。BOM作为一种促进互操作性、重用性和可组合性的实现机制,鼓励灵活、快速、有效地开发和管理模型。通过研究BOM模板规范和体系结构,设计基于BOM的通用HLA仿真框架,实现通过基于BOM的仿真模型组件快速组合和重用,从而构建具有功能可扩展性和规模可控性的多样性联邦成员和联邦,提高分布式仿真系统的重用性和互操作性。

基于BOM的仿真模型组件研究

基于组件的建模方法能有效地减少建模任务的复杂性,通过重用、替换、改进以及扩展组件实现快速构建动态的仿真系统和仿真环境。首先描述BOM(Base Object Model,基本对象模型)模板结构,接着分析BOM与SOM(Simulation Object Model,仿真对象模型)/FOM(Federation Object Model,联邦对象模型)的关系,设计基于BOM的仿真模型组件。从语法层和语义层研究仿真模型组件的基本结构,比较仿真模型组件与软件工程组件的区别,并通过支持工具进行仿真模型组件的设计与开发。

基于BOM的HLA仿真系统可信性研究

可信性是系统仿真的关键要素。基于BOM的HLA仿真系统可以从仿真模型层次上提高系统的重用性和互操作性。为了确保该类仿真系统的可信性,在建模与仿真全生命周期中开展VV&A研究,十分必要。介绍了基于BOM的HLA仿真系统的FEDEP模型,并简要提出其VV&A过程,重点对用户模型、仿真模型组件及联邦成员的V&V展开研究,最后将这些研究应用于×××反舰导弹突防联邦仿真中。结果表明:提出的VV&A过程切实可行,保障了系统的可信性。

基于DEVS的BOM组件与仿真引擎研究

在组件化建模与仿真领域内,基于BOM规范的KD-XSRFrame组件建模与仿真框架得到了广泛的应用,但是以离散时间仿真为手段的设计模式使得由BOM组件构成的仿真系统性能不高。因此,如何提高运行效率成为基于BOM的组件式建模与仿真必须解决的问题。根据现有组件系统的不足,引入离散事件的概念重新设计了BOM组件模型和仿真引擎,提出了基于离散事件系统规范的BOM组件建模框架,实现了以事件为中心的仿真引擎。测试结果表明该系统能有效地减少模型调用和引擎工作的开销,显著地提升了整个仿真系统的运行性能。

四个数值预报模式对四川强降水过程预报能力评估

为衡量数值模式对强降水过程的预报能力,选取欧洲中期天气预报中心(the European Centre for Medium-Range Weather Forecasts,ECMWF)数值预报产品、国家气象中心区域中尺度数值预报产品(China Meteorological Administration Mesoscale Model,CMA-MESO 3KM)、西南区域中心中尺度模式系统(Southwest Center WRF ADAS Real-time Modeling System,SWC)、国家气象中心全球数值预报系统(China Meteorological Administration for Global Forecast System,CMA-GFS)4个模式预报产品,利用目标对象检验法,对四川2018—2020年共93次强降水过程(≥25 mm·d^(-1))从降水位置、降水面积、降水强度等方面进行检验,在此基础上重点讨论36 h预报时效模式的预报能力。结果表明:(1)随着预报时效越临近,各模式预报平均水平越高,且整体对雨带位置把握较好,更具有参考性。(2)各模式对锋面降水过程预报能力较强,对暖区降水过程预报能力较差。(3)暖区强降水过程可在大尺度模式基础上结合本地中尺度模式进行订正;锋面降水过程则以ECMWF模式预报为基础,参考CMA-MESO 3KM模式对大雨及以上量级降水落区和量级进行调整。

基于BOM的仿真可组装性研究

仿真可组装性研究是构建大规模仿真系统、复用仿真构件的关键环节,基本对象模型(BOM)的提出有助于可组装性研究的发展。通过分析BOM中的仿真构件元数据,对语法可组装性进行了研究,实现对备选构件的初步筛选;然后在基于本体映射的思想上研究了语义可组装性,实现对备选构件的进一步筛选;并分别给出了相应的算法。试验结果表明,所提方法能够准确有效地满足用户对参与组装的仿真构件进行筛选的需要。

基于BOM的组件并行仿真引擎研究与实现

在组件化建模与仿真领域内,基于BOM规范的组件建模与仿真环境KD-SmartSim得到了广泛应用,它通过RTI实现了组件仿真系统的并行运算,但是其运行性能较低。讨论了KD-SmartSim系统存在的不足,在继承其基于BOM规范组件建模的基础上,提出了新的支持组件并行化计算的结构,设计了SPMD运行模式的并行组件仿真引擎,研究和开发了各种模型计算需要的仿真服务,实现了支持串行和保守时间推进机制的组件并行仿真引擎原型系统。测试结果表明该系统具备BOM组件仿真运行必须的功能,能够显著地提升组件系统的运行性能。