Fundamental Issues Towards Unified Design Theory of Recycled and Natural Aggregate Concrete Components

In the past 20 years,recycled aggregate concrete(RAC),as a type of low-carbon concrete,has become a worldwide focus of research.However,the design methodology for RAC structural components remains a challenge.Consequently,demands for a unified design of natural aggregate concrete(NAC)and RAC components have been presented.Accordingly,this study analyses the necessity of a unified design theory and provides an in-depth demonstration of the strength determination,compressive constitutive relationship,and design method of concrete components.The coefficient of variation of RAC strength is found to be generally higher than that of NAC strength.The compressive and tensile strengths of RAC can be defined and determined using the same method as that used for NAC.The uniaxial compressive constitutive relationship between NAC and RAC has a unified mathematical expression.However,the elastic modulus of RAC decreases,and its brittleness exhibits an increasing trend compared with that of NAC.Finally,to unify the design formulae of RAC and NAC components for bearing capacity,modification factors for RAC components are proposed considering safety and reliability.Additionally,the feasibility of the proposed unified time-dependent design theory is demonstrated in terms of conceptual design and structural measures considering the effects of strength degradation and reinforcement corrosion.It is believed that this study enriches and develops the basic theory of concrete structures.

Scavenging Microwave Wireless Power:A Unified Model,Rectenna Design Automation,and Cutting-Edge Techniques

While sufficient review articles exist on inductive short-range wireless power transfer(WPT),long-haul microwave WPT(MWPT)for solar power satellites,and ambient microwave wireless energy harvesting(MWEH)in urban areas,few studies focus on the fundamental modeling and related design automation of receiver systems.This article reviews the development of MWPT and MWEH receivers,with a focus on rectenna design automation.A novel rectifier model capable of accurately modeling the rectification process under both high and low input power is presented.The model reveals the theoretical boundary of radio frequency-to-direct current(dc)power conversion efficiency and,most importantly,enables an automated system design.The automated rectenna design flow is sequential,with the minimal engagement of iterative optimization.It covers the design automation of every module(i.e.,rectifiers,matching circuits,antennae,and dc–dc converters).Scaling-up of the technique to large rectenna arrays is also possible,where the challenges in array partitioning and power combining are briefly discussed.In addition,several cutting-edge rectenna techniques for MWPT and MWEH are reviewed,including the dynamic range extension technique,the harmonics-based retro-directive technique,and the simultaneous wireless information and power transfer technique,which can be good complements to the presented automated design methodology.

基于UML/Power Designer的信息系统分析方法

本文主要针对基于UML/PowerDesigner的信息系统分析方法进行研究:在基于面向对象UML的平台上,以CRM客户关系管理信息系统为研究对象,对其需求模型,总体设计模型和详细设计模型进行了分析设计,并采用了基于UML建模语言的CASE工具PowerDesigner进行进一步的辅助分析和设计,得到了CRM的相关实现模型。本文的研究对管理信息系统的分析方法提供了一种实用的技术途径。

COLLABORATIVE DESIGN OF MULTIPHYSICS PROBLEMS

Collaborative design is recommended to solve multiphysics problems （MPPS）. Firstly, mathematical model of MPPS is constructed and solved by a proposed partitioned method, analysis of which suggests that collaborative design be feasible to solve MPPS. As the key technology of col-laborative design of MPPS, a task collaboration algorithm is then proposed. To develop the applica-tion framework of collaborative design, applied unified process（AUP） is proposed based on rational unified process（RUP）. Then AUP is used to develop the collaborative design platform, whose function framework is constructed according to the process of project management. Finally three MPPS are solved on this platform and the results suggest that the proposed model, algorithm and framework be feasible.

Novel Aspects of Constructal Law: Four Distinct and Competing Goals in Flow Channels Design

Constructal law explains the sense of evolution (morphing to get access to flows) of finite size systems, but paradoxes do exist as not all vegetables have a tree form. Also, nature does not improve all animals for displacement. This work aims at creating a model to explain those paradoxes about constructal law. It adopted the system engineering technique of segregation between functions (abstract goals) and solutions (physical entities). Further, this work introduced the assumptions of flow under external threats and imperfect channels (subject to leakages and suboptimal form). Results showed that there are always elements doing four functions in all types of channels: to reduce entropy, to protect channel, to retain integrity and to drive flow. Although the four functions are always present, natural systems typically privilege one function over others, depending on environmental demands. As a solution to improve flows, animal brains also fit in the model of four functions. Human mind seems to have groups of instincts associated with each of the four channel design functions, leading to four behavior phenotypes and four motivations (prominence, inclusiveness, negativity prevention and tradition). Finally, this model (channels need to meet four goals) unified physics and animal psychology and extended applications of Constructal law to the fields of systems engineering methods, management, and psychological science.

Automated Design and Visualization System of a House Foundation from Blocks

This article analyzes creation methods of automated design system, presents design system of a house foundation from blocks. The creation methods of automated design system of a house foundation from blocks are discovered with Unified Modeling Language. Analyzed objects-classes： block, specification, model. Graphical system can design foundation, form specification of objects and create 3D model of house foundation. There are several types and different dimensions of concrete blocks. The program optimally arranges selected blocks so that monolithic parts will be minimal volume. Program selects a house foundation blocks from database by using ActiveX Data Objects technology, which by programming method connects drawing and database. Drawing＇s graphical objects have additional data from which exchange of data between graphical system and database is executed. Visualization system and example of house foundation from blocks project with specifications is presented. Creation problems of automated design system are discussed and conclusions are made.

ThinkDesign技术在创新设计中的应用

随着三维CAD技术应用的不断深入，表明了在参数化CAD技术基础上对三维CAD技术的新需求，以适应企业产品创新设计的新需要．结合ThinkDesign软件技术应用实例，阐明CAD技术对企业开展创新设计的帮助，得出了参数化CAD技术将向创新协同CAD技术的方向延伸。

面向构网逆变器的虚拟振荡器控制技术:统一设计框架与关键问题探讨

虚拟振荡器控制是近年来新兴的逆变器构网型控制方式,相较于下垂控制、虚拟同步发电机控制等现有构网型控制而言,其在动态响应速度与大扰动稳定性等方面具有优势。首先基于已有研究介绍了虚拟振荡器控制的基本原理及现有类型,接着针对虚拟振荡器设计目前缺乏普适性的问题提出了虚拟振荡器控制的统一设计框架及详细设计步骤,并以自行设计的两类虚拟振荡器为例,通过时域仿真验证了所提设计框架的可行性;最后从功率调度能力、抗扰动稳定运行能力以及实际应用能力3方面针对目前限制虚拟振荡器控制技术发展的关键问题进行了梳理与探讨,并给出了解决思路与未来的研究方向。

基于统一数据源的航天器数字化协同设计模式研究

航天器的研制是一项极为复杂的系统工程,涉及项目方案的设计与细化、众多参研单位的参与、高标准的技术指标要求以及高度耦合的设计环节。其中,大量的协同讨论与分析是必不可少的,但传统协同工作模式往往缺乏持久性,难以满足各学科的高效协同需求。因此,必须引入新的手段以提升协同设计的质量与效率。采用基于统一数据源的设计、制造、装配与测试模式,文章实现了多专业、多岗位之间的联合设计与实施,在航天器的全寿命周期内开展了仿真分析及数据管理,旨在优化整星设计参数,最终提升型号研制的效率与效益。

基于空间明亮度评价标准的写字楼大堂照明设计与教学

国内的照明设计标准主要是基于水平面的照度评价室内空间亮度,但是仅采用水平面照度而忽视三维立体空间的亮度进行评价,不能真实反映室内空间的亮度。为此,日本松下电器公司和日本高校研究人员共同提出了空间明亮度评价标准(Spatial Brightness Evaluation Standard,FEU),一种用于评价室内建筑立体空间明亮感的新方法。本文采用FEU评价标准并结合《建筑照明设计标准》(GB 50034—2013),为典型的写字楼大堂设计了三种不同立体空间亮度的照明方案,并进行了方案的对比分析。结果表明,写字楼大堂的照明设计融合水平面照明与立面照明方法,营造出视觉感更舒适的立体空间光环境。使用LED线性天花洗墙灯对立面呈现的灯光效果更为均匀,统一眩光值(Unified Glare Rating,UGR)保持在较低数值,可为写字楼大堂打造一个更愉悦舒适的视觉氛围环境。采用可靠的调光系统设计符合需求的照明场景,可实现照明节能52.27%。立体空间的照明设计方法是一种先进的现代化写字楼大堂的照明设计方法,丰富了《照明设计》课程的教学内容,提高了教学效果。

基于统一架构框架(UAF)的体系协同作战架构建模研究

面向体系对抗趋势下不断提升的战争复杂性,引入基于模型的系统工程方法到复杂体系作战建模设计中,通过梳理体系作战的建模需求与内在机理,采用统一架构框架(Unified Architecture Framework,UAF)提出基于场景的体系作战建模方法。以多目标搜索攻击任务为案例,构建了相应的战略、运行、资源、服务等视图模型,并开展了逻辑仿真验证,可为体系作战设计与建模仿真提供依据及参考。

基于故障电流控制的新型UPFC-FCL设计

针对统一潮流控制器(UPFC)的系统短路保护问题,提出了一种基于故障电流控制的新型限流式统一潮流控制器(UPFC-FCL)拓扑结构。通过在限流电抗支路上投切耗能电阻,配合UPFC并联侧控制,限制线路故障电流的上升速率和幅值并保护设备安全。详细阐述了拓扑结构与工作原理,并进行了数学建模和关键参数设计。仿真结果表明,该新型UPFC-FCL能较精确地控制故障电流并可灵活调整限流值以配合继电保护电流整定值和断路器遮断电流,故障消除后恢复迅速且适用于多次故障和自动重合闸等情况,同时降低了装置成本以及UPFC的损坏风险。

面向并行工程的组合夹具辅助设计系统设计与开发

提出了一种基于Web的计算机辅助夹具设计系统原型 ,并采用基于UML的ICONIX开发过程实现 ,通过用例图、对象类图、Robustness图和顺序图明确了系统对象类的功能。

汽车覆盖件设计全流程CAD/CAE系统开发与应用

为解决目前CAD/CAE系统中数据转换精度损失和设计变更引起分析模型重复建模的问题,基于UGSNX平台开发了面向汽车覆盖件设计全流程的CAD/CAE集成系统FASTAMP-NX,该系统完全集成于NX环境,并基于特征造型技术建立了设计和分析相统一的关联参数化模型,避免了数据转换引起的精度损失和重复建模问题.系统求解器基于有限元逆算法和改进的动力显式算法,可应用于产品设计、工艺设计和虚拟试模的全流程,真正实现了"设计-分析-修改-优化"的闭式循环,极大地提高了汽车覆盖件产品和模具设计与分析的效率.

一种基于结构查询的UML设计模式识别方法

随着模型驱动技术的逐渐成熟和广泛应用,大量反映程序结构、行为以及性质的模型产生于软件的开发过程中,并成为软件文档的重要部分保存下来。其中,尤以UML模型的应用最为广泛,也因此形成了通过理解UML模型来理解大规模、高复杂性软件系统的研究思路。对UML模型理解的一个难点是如何有效地从大量复杂的模型中,快速查找并定位具有一定结构特征的模型片段。幸运的是,设计模式的普遍应用为我们快速、高效地理解和定位模型提供了一条重要的线索。然而,随着技术的发展,设计模式数量在不断增长,其自身在应用中的结构也在微妙变化,这些都给相应查询和识别工具的开发带来一定的困难。文中从查询和匹配UML模型中特定结构的角度入手,利用UML自身特点设计相应查询算法,通过分析和理解设计模式的结构特征,从UML模型中查询相应的设计模式,以达到灵活和高效地理解软件系统的目的。

基于返步法的区域稳定控制器统一设计

提出了一种可有效解决区域功率振荡问题的统一控制器设计方法。该方法解决了各控制器间因数学模型和采用控制理论的不同所可能造成的协调配合问题。在系统建模过程中,打破了对网络拓扑、元件模型精细程度,以及元件模型适应范围的束缚,建立了基于全局信号的区域互联电力系统的统一模型;在控制规律的推导过程中,利用模型的结构特征,将返步法与先进的控制理论相结合,解决了系统参数不确定和模型误差问题。在MATLAB环境下的相关仿真结果验证了所提出的方法的有效性。

统一建模语言UML及其建模实例

以统一建模语言 (UnifiedModelingLanguage ,UML)的九种图为重点 ,简要介绍了UML的基本概念、历史、内容及其应用 ;并通过对一个超级市场销售管理系统的实际建模 。

三维钢结构CAD软件中的节点设计

介绍了面向对象分析与设计的基本思想，利用Factory Method设计模式，解决了钢结构节点设计CAD软件中节点多样的难题。该方法可以大幅度提高程序员的工作效率。

核心业务一体化的电网智能调度支持平台架构设计

为了解决二次一体化的支撑平台中核心业务要求稳定高效、第三方业务支持开放接入之间的矛盾,并解决综合数据中心的定位和运维问题,提出了一种电网智能调度支持平台的实现架构。该方案由基础技术支持、综合数据中心和标准总线等部分组成,以核心业务一体化设计为基础构建电网全景模型和数据,并为第三方系统提供开放标准接口,实现多业务间的协同。与传统方案相比,本方案既能方便地实现业务间协同交互,又保证了核心业务的稳定、高效和安全,为信息的集成和综合电网分析提供了良好的支持。

基于场景构件式实时软件设计的一致性检验

在复杂的实时软件系统中使用构件式设计方法,已成为目前软件工程中的研究热点.如何有效地验证实时软件的设计是否满足给定的时间规约,是实时计算领域中的主要挑战之一.通过在接口自动机模型中添加时间区间标记,来扩展其对实时系统接口行为的表达能力;使用实时接口自动机网络来描述实时软件系统的构件式设计模型;使用带布尔不等式时间约束的UML顺序图表示基于场景的需求规约,对系统设计阶段实时软件构件的动态行为进行形式化分析与检验.通过对实时接口自动机网络状态空间的分析,构造了其可兼容的整型状态等价类空间的可达图,并在此基础上给出了验证算法,以检验构件式实时软件系统的设计与带时间约束的场景式规约之间的一致性.