AAK Theorem and a Design of Multidimensional BIBO Stable Filters

Rational approximation theory occupies a significant place in signal processing and systems theory. This research paper proposes an optimal design of BIBO stable multidimensional Infinite Impulse Response filters with a realizable (rational) transfer function thanks to the Adamjan, Arov and Krein (AAK) theorem. It is well known that the one dimensional AAK results give the best approximation of a polynomial as a rational function in the Hankel semi norm. We suppose that the Hankel matrix associated to the transfer function has a finite rank.

A Rework Reduction Mechanism in Complex Projects Using Design Structure Matrix Clustering Methods

To reduce the uncertainty and reworks in complex projects,a novel mechanism is systematically developed in this paper based on two classical design structure matrix(DSM)clustering methods:Loop searching method(LSM)and function searching method(FSM).Specifically,the optimal working areas for the two clustering methods are first obtained quantitatively in terms of non-zero fraction(NZF)and singular value modularity index(SMI),in which the whole working area is divided into six sub-zones.Then,a judgement procedure is proposed for conveniently choosing the optimal DSM clustering method,which makes it easy to determine which DSM clustering method performs better for a given case.Subsequently,a conceptual model is constructed to assist project managers in effectively analyzing the network of projects and greatly reducing reworks in complex projects by defining preventive actions.Finally,the aircraft design process is presented to show how the proposed judgement mechanism can be utilized to reduce the reworks in actual projects.

Thermal resistance matrix representation of thermal effects and thermal design of microwave power HBTs with two-dimensional array layout

Based on the thermal network of the two-dimensional heterojunction bipolar transistors(HBTs) array, the thermal resistance matrix is presented, including the self-heating thermal resistance and thermal coupling resistance to describe the self-heating and thermal coupling effects, respectively.For HBT cells along the emitter length direction, the thermal coupling resistance is far smaller than the self-heating thermal resistance, and the peak junction temperature is mainly determined by the self-heating thermal resistance.However, the thermal coupling resistance is in the same order with the self-heating thermal resistance for HBT cells along the emitter width direction.Furthermore, the dependence of the thermal resistance matrix on cell spacing along the emitter length direction and cell spacing along the emitter width direction is also investigated, respectively.It is shown that the moderate increase of cell spacings along the emitter length direction and the emitter width direction could effectively lower the self-heating thermal resistance and thermal coupling resistance,and hence the peak junction temperature is decreased, which sheds light on adopting a two-dimensional non-uniform cell spacing layout to improve the uneven temperature distribution.By taking a 2 × 6 HBTs array for example, a twodimensional non-uniform cell spacing layout is designed, which can effectively lower the peak junction temperature and reduce the non-uniformity of the dissipated power.For the HBTs array with optimized layout, the high power-handling capability and thermal dissipation capability are kept when the bias voltage increases.

Development of Product Design Projects Applying Specifications and Factors Matrix (SFM) as a Support Tool in Higher Education

The application of work strategies taking into account, from the initial stages, all the factors involved in the product design process is considered essential by the researches to generate higher quality products, assess users’ needs and anticipate design problems. This paper presents two approaches of design project development, denominated respectively: projects with imposed specifications and projects with derived specifications and proposes the use of the matrix that integrates specifications and design factors (SFM). This design support tool complements others already used in the development of product concepts by higher education students, increasing the capacity of synthesis and structuring of information in order to facilitate decision-making into the design process. Its elaboration implies understanding of objectives, identifying of factors and establishing of specifications. At the same time, it aims to foster the reflection process and an integrated information analysis. The application of SFM and its contribution to different project approaches are shown in this paper.

Observer design for matrix second-order linear systems: a parametric approach

The issue of designing a type of generalized Luenberger observers for matrix second-order linear (MSOL) systems was addressed in the matrix second-order framework. By introducing the concept of stable matrix pair for MSOL systems, sufficient and necessary conditions for the design of the type of generalized Luenberger observers were given under the assumption of controllability and observability of the MSOL system. Based on the proposed conditions and the right coprime factorization of the system, a parametric approach to the design of such type of observers was presented. The proposed approach provides all the degrees of design freedom, which can be further utilized to achieve additional system specifications. A spring-mass system was utilized to show the effect of the proposed method.

Schedule Model for Project Portfolio Based on Design Structure Matrix

To improve the enterprise resource utilization and shorten the cycle of the whole project portfolio, a scheduling model based on Design Structure Matrix （DSM） is built. By setting the project activity weight index system and calculating the activity weight for the project portfolio, the constraint relationship between project portfolio information and resource utilization, as the two dimensions of the DSM, are fully reflected in the sched- ule model to determine the order of these activities of project portfolio. A project portfolio example is given to il- lustrate the applicability and effectiveness of the schedule model.

建筑智能化系统顶层设计方法探讨

通过自上而下地展开,吸收质量功能配置的思想,对建设过程中影响智能化系统的因素进行统筹考量。通过逐层迭代的方式,直观展示不同技术方案对业主满意度的影响,为建筑设计提供可比较的方案效益评价,也为设计明确后续技术路径。

Matrix Operations Design Tool for FPGA and VLSI Systems

Embedded systems used in real-time applications require low power, less area and high computation speed. For digital signal processing, image processing and communication applications, data are often received at a continuously high rate. The type of necessary arithmetic functions and matrix operations may vary greatly among different applications. The RTL-based design and verification of one or more of these functions could be time-consuming. Some High Level Synthesis tools reduce this design and verification time but may not be optimal or suitable for low power applications. The design tool proposed in this paper can improve the design time and reduce the verification process. The design tool offers a fast design and verification platform for important matrix operations. These operations range from simple addition to more complex matrix operations such as LU and QR factorizations. The proposed platform can improve design time by reducing verification cycle. This tool generates Verilog code and its testbench that can be realized in FPGA and VLSI systems. The designed system uses MATLAB-based verification and reporting.

阴极阳极协同电催化降解高硫酸盐废水中活性染料

采用辊压法制备炭黑/聚四氟乙烯(C/PTFE)气体扩散电极,并对其微观结构进行表征。构建以掺硼金刚石(BDD)为阳极,C/PTFE气体扩散电极为阴极的电催化氧化体系,阳极硫酸盐活化技术与阴极原位合成H_(2)O_(2)技术协同处理高硫酸盐废水中的活性艳蓝X-BR。结果表明,制备的C/PTFE电极作阴极时,电催化氧化体系中活性艳蓝X-BR去除效果优于铂(Pt)阴极体系和不锈钢(SS)阴极体系。通过猝灭实验发现,BDD/(C/PTFE)电化学体系中产生的SO_(4)^(·-)和·OH等高活性物质间相互转化,为电化学体系提供了可持续氧化能力,二者对于体系中活性艳蓝X-BR去除贡献度分别为54.51%和25.75%。建立了电化学氧化体系中TOC去除率及单位能耗二次项模型,通过响应曲面法优化降解含活性艳蓝X-BR废水的运行参数。优化条件下(初始pH=5.0,电流密度=120 mA/cm^(2),C_(Na_(2)SO_(4))=0.25 mol/L,C_(活性艳蓝X-BR)=1 000 mg/L),电解120 min,废水TOC去除率为63.86%,体系单位质量TOC能耗为256.02kW·h/kg,继续电解至240 min,可将水中的活性艳蓝X-BR完全矿化,为双电极协同电催化氧化处理高硫酸盐有机废水提供理论支持。

基于TRIZ冲突解决理论的老年用品可用性设计方法

为有效解决老年用品可用性设计中的冲突问题,将可用性与冲突解决理论融合,提出一种老年用品可用性设计方法。由于传统TRIZ参数对老年用品的不适用和模糊性,在老年用品的可用性设计中难以获得解决方案。从老年用品的可用性设计冲突入手,将TRIZ的工程参数筛选出老年可用性设计领域的26个专属可用性参数,采用灰色关联分析法对参数进行可用性分类,从感知层、认知层和执行层进行冲突矩阵的重构;建立了基于冲突解决理论的老年用品可用性设计过程模型,并应用于老年药盒的可用性设计实例。结果表明:文中方法能系统化地解决老年用品可用性设计中的冲突问题,使老年用品可用性设计方法和TRIZ的应用领域得到进一步拓展。

布料包装设备中翻折机构的结构设计与运动分析

为解决中小型染整企业需要机械设备实现布料包装的问题,利用公理化设计理论,根据用户需求解析其布料包装设备中翻折机构的功能要求和结构设计要素。通过耦合设计分析提出符合独立性公理的机构设计方案。选取右侧由曲柄滑块机构与凸轮机构串联而成的六杆机构作为设计对象,利用位移矩阵法得到曲柄滑块机构尺寸,解析滑块位置与曲柄转角的关系。同时,分别选用等速运动规律和正弦加速度运动规律设计推程阶段廓线和回程廓线。此外,对翻折机构进行运动仿真得到翻折板的角位移、角速度和角加速曲线。研究表明,翻折板的运动特性满足设计要求并符合实际需求。

基于聚类算法的自动变速箱装配模块划分研究

自动变速箱可实现换挡变速功能,是车辆系统中传递动力的关键部件。由于其结构狭窄紧凑、零件数量繁多,导致装配复杂度大大增加。模块划分是产品模块化设计的关键步骤,可以将系统整体拆分形成若干个高内聚低耦合的模块,从而达到降低产品装配难度的目的。模糊C-均值聚类算法(FCM)是实现模块划分的传统方法,然而其对初值敏感,容易收敛到局部极值点。FCM与优化算法的结合有利于避免陷入局部最优解的情况,因此提出使用基于遗传模拟退火算法的FCM方法进行装配模块划分以获取自动变速箱模块的最佳划分方案。以重庆铁马变速箱有限公司的自动变速箱为例,使用所提方法对其进行装配模块划分,将所得模块划分结果与实际方案进行对比,证明了方法的准确性和有效性。

MAX相陶瓷增强金属基复合材料:制备、性能与仿生设计

由于原子间存在共价键、金属键与离子键的混合键合状态,MAX相陶瓷兼具金属和陶瓷材料的性能特点,并且常与金属之间表现出良好的润湿性,有助于形成强界面结合,独特的层状原子结构使MAX相陶瓷表现出良好的断裂韧性、阻尼与自润滑性能。因此,作为金属基复合材料的增强相,MAX相陶瓷具有显著优势,本文着重介绍相关研究进展。目前,MAX相陶瓷增强金属基复合材料主要通过搅拌铸造、粉末冶金和熔体浸渗等途径制备,得到的复合材料表现出优于金属基体的强度、硬度与模量,同时还具备良好的耐磨、导电、抗电弧侵蚀等性能。此外,借助真空抽滤、冰模板等工艺可实现超细片状MAX相陶瓷粉体的择优定向排列,然后利用金属熔体浸渗多孔陶瓷骨架,可获得具有类贝壳结构的MAX相陶瓷增强金属基仿生复合材料,进一步提升材料的强韧性能。MAX相陶瓷增强金属基复合材料在承载、电接触等应用领域具有显著优势和广阔前景。

复杂装备数字孪生跨域高效协同建模平台与应用

随着装备朝着复杂化、集成化、智能化方向发展,如何快速准确构建高保真数字孪生模型是复杂装备智能运维的基础性工作与最大技术障碍。提出依靠设计结构矩阵(DSM矩阵)进行任务耦合度优化与智能分发的策略,实现复杂装备数字孪生多点建模全方位动态监管;基于DSM矩阵特点提出一种改进遗传算法,改进优化流程并提高任务处理速度;最后,开发基于Web的分布式协同建模平台,实现了丝杠试验台数字孪生实体模型的协同构建。试验结果表明:该试验台协同建模效率得到了显著提升,为复杂装备数字孪生模型快速构建提供了工程案例,为复杂装备智能运维提供了技术支撑。

生物医用支架仿生设计及在组织工程中的应用

背景:基于解剖学对生物组织功能与结构的认识,对于具有恢复、维持或改善组织功能的生物活性材料仿生设计是目前再生医学领域研究的热点。目的:从生物医用支架的机械性能、三维空间结构和生化活性对细胞行为的影响进行讨论,并综述生物医用支架在组织工程领域的应用。方法:应用计算机检索中国知网、万方、Web of Science、PubMed数据库2003年1月至2023年4月发表的文献,中文检索词为“细胞外基质,组织工程,支架,生物材料,仿生结构,机械性能,三维结构,腱骨界面,骨软骨,神经导管,人造血管”;英文检索词为“extracellular matrix,tissue engineering,scaffolds,biomimetic structures,biomaterials,tendon bone interfaces,osteochondral,neural conduits,artificial blood vessels”。结果与结论:细胞处在一个复杂且动态变化的三维环境中,因此细胞外基质是生物材料模拟的最终目标,在设计生物医用支架的仿生结构时需要与其所处真实的微环境相似,让细胞可以正常地贴壁、生长和迁移,并保持其多样的生理功能。生物医用支架在机械性能、三维空间结构以及生物化学性质方面对细胞外基质的仿生设计可以对组织修复过程中的细胞起到决定性作用,从而影响组织修复最后的结果。进行仿生设计的生物医用支架在腱骨界面、骨软骨界面、神经、血管再生等领域已有广泛的应用,在临床上提供了一个有前途的新思路。

产品设计专业“矩阵式管理”教学模式探索与实践

文章旨在探索“矩阵式管理”教学模式在产品设计实践教学中的应用,旨在提升学生的实践能力与创新能力。文章首先概述了矩阵式管理教学模式的基本概念与特征,强调了其在教育领域中的创新性和优势。其次,从“矩阵式管理”教学模式的构建机制和“矩阵式管理”教学模式的构建途径两方面阐述了产品设计专业“矩阵式管理”教学模式是如何构建的。最后,将构建机制和构建途径应用于实践教学中并进行验证与研究,以期培养出能适应未来需求的设计人才。

石墨烯增强钛基复合材料研究进展

非连续增强钛基复合材料(DRTMCs)具有高比强度、低密度、优异的耐蚀性等诸多特性,在航空航天、国防工业、交通运输等领域具有广泛的应用前景。石墨烯具有良好的本征物理和力学性能,是近年来的二维碳纳米“明星”材料,被视为极具潜力的DRTMCs纳米增强体。国内外研究者聚焦DRTMCs设计与制备,突破了低温快速成型和界面改性等关键技术,初步实现了界面精细调控和微观构型,获得石墨烯在钛基体中的本征增强,制备出强塑性匹配较好的DRTMCs。简要综述近些年来石墨烯增强钛基复合材料的设计方法和制备工艺,探讨界面反应、界面结构、微观构型等关键因素对复合材料力学性能和失效机制的影响规律,并提出石墨烯增强钛基复合材料未来的发展方向。

基于Matrix 2003与效应的产品工业设计创新方法研究

产品创新直接关系到产品自身在市场的竞争力.当前工业设计产品创新缺乏一些具体的理论支撑,因此需要将其他领域的理论融入工业设计当中能够有效提高新产品设计的效率.为提高工业设计中的创新效率,介绍了一种将工业设计理论与Matrix 2003结合的创新原理,总结了六大设计要素,并利用这些设计元素将创新原理按照"时间-空间-交互"三大维度进行划分,形成一种独特的创新矩阵,以最终理想产品所达到的效应为目标进行求解,从而为工业设计产品的创新提供了一种快捷有效的方法流程.最后以快递车车厢的改进为工程实例进一步验证方法的有效性和实用性.