强非线性振动周期的样条边值方法

强非线性振动周期的样条边值方法王新立（国防科技大学科研处）一引言非线性振动问题，是工程中经常遇到的问题，对于这一类问题的求解方法，目前主要有摄动法、Ｌｉｎｄｓｔｅｄｔ法、多尺度法、渐近法等等。但这些方法仅限于其振动微分方程中的非线性项小于线性项的弱非...     

二阶强非线性非自治系统周期解的能量迭代法

给出了确定一般二阶强非线性非自治系统周期解的能量迭代方法。该方法给出了二阶强非线性非自治系统主谐波共振和超谐波、次谐波共振周期解存在的必要条件，求得了这些周期解的近似解析表达式，并且得出了解的稳定性判据。近似解析解表达式由计算机辅助推导，计算程序集推导、计算、数值解以及绘图于一体。例子表明，该方法不仅有效而且结果精度较高。     

如何选择非线性编辑系统

随着计算机技术的迅猛发展，以及超大规模集成电路技术、信息处理与数字视频压缩技术的突破，不但使计算机可以实时采集和重放高质量的视频图像，而且电视节目制作人员还可借助于计算机数字视频技术对电视图像进行超乎想象的创作，从而把电视节目制作带人了一个数字化的新境地。这就是当前在电视节目后期制作中最具革命性的、最引人注目的、最有发展前景的非线性编辑系统。一、非线性编辑系统及其工作过程和优点非线性编辑系统是一种被各国电视机构日益广泛采用的以计算机为平台的电视节目后期制作设备。此系统以硬磁盘为记录媒体，可以对节…     

艺术设计专业“计算机辅助设计”课程中存在的问题和解决办法——以江南大学设计学院教学为例

艺术设计和计算机的关系日渐密切,如何更好的利用计算机以及网络达到设计目的,是目前艺术设计专业教学中不断探索的问题。本文以江南大学设计学院的“计算机辅助设计”课程教学为例,探讨了目前“计算机辅助设计”课程教学现状及存在问题,并提出了改进的方法,以及教学实践中的具体实施和探索。目的在于更好的利用计算机以及网络达到设计目的。     

数字化电影制片

传统电影制作与计算机应用相结合的而形成的数字化电影制片方式覆盖了创作和制作的各两方面，本文重点介绍了：基于计算机模拟和辅助设计的数字形象化预审视，基于计算机摄影机运动控制和基于图形工作站的画面数字制作方法以及基于将画面和声音转换为随机的计算机数据的数字非线性编辑等，涉及到电影制片的先期制作，摄制和后期制作几个方面的数字化问题，也介绍了在数字化环境下出现的信息交流，资源共享和平行作业等势头。     

光学薄膜非线性参数的快速测量与分析

提出一种测量非线性光学薄膜非线性参数的方法，测量了ＺｎＳｅ非晶态薄膜的非线性折射率和消光系数。在此方法中，实验数据的计算与处理由一套计算机软件完成。对这种测量方法的精确性及实用性进行了分析和讨论。     

二元机翼非线性颤振系统的若干分析方法

颤振是气动弹性力学研究最重要的问题之一。本文综述了亚音速条件下二元机翼非线性颤振研究的若干分析方法。目前,基于二元机翼的非线性颤振分析采用的定性方法主要是常微分方程定性理论,定量方法则有等效线性化法、描述函数法、谐波平衡法以及摄动法等。对所提及的方法做了简要的评述和比较,指出了进一步研究的问题。     

求解电力系统动态经济调度算法综述

电力系统动态经济调度是一个多约束条件、非线性,高维,多约束混合整数的优化问题,因此很难求出准确解,目前主流的方法有传统的数学方法以及智能优化算法。     

合班问题的数学模型

本文首次建立了我国高校计算机排课时合班问题的数学模型，它是一个非线性的整数规划问题。本文将集中讨论二维合班问题。     

样条有限条法分析板的几何非线性振动特性

本文利用样条有限条法分析矩形板的几何非线性振动特性问题,指出了试函数的选取方法,并利用B样条函数的特点得出了精确地求非线性刚度矩阵的一种方法.该方法具有占计算机内存少、计算速度快、收敛快、精度高的特点.该方法还适用于响应分析.     

Rationality Analysis and Direct Parametrization of Generalized Offsets to Quadrics

In this paper, working over algebraically closed fields of characteristic zero, we present formal proofs for a complete analysis of the rationality of generalized offsets to all irreducible quadrics, and we show how to derive rational parametrizations of the offsets, when they are rational, from the parametrization of the original quadric. This is achieved by means of a surface, constructed without implicitizating, that is either linear in one variable or tubular. More precisely, we prove that generalized offsets to elliptic and hyperbolic paraboloids are rational, generalized offsets to parabolic cylinders are rational, and generalized offsets to hyperbolic cylinders are irreducible and not rational. Also we prove that generalized offsets to elliptic cylinders of revolution have two rational components, and that generalized offsets to non-revolution elliptic cylinders are irreducible and not rational. Furthermore, we state that generalized offsets to cones of revolution have two rational components and to non-revolution cones are irreducible and not rational. In addition, an offset to the sphere has two rational components and to an ellipsoid is rational. Finally, we prove that generalized offsets to one and two-sheeted hyperboloids are rational. Received: December 3, 1998; revised version: September 23, 1999     

Blockchain breeding grounds: Asia's advance over the USA and Europe

Blockchain is argued to disrupt almost every industry and research field. Among other technologies, it contributes to the next fourth industrial revolution. While prominent technologies, such as AI and IoT, have already proven their potential and value in many applications, Blockchain applications have gathered only limited appeal. We ask, which countries drive inventive activity in Blockchain and to which magnitude and type. Using worldwide Blockchain patent applications from 2009 to 2020 as inventive outcome indicators the National Breeding Ground (NBG) index and the International Breeding Ground (IBG) index are calculated. The NBG index is related to the interest of a country to file Blockchain patents in its domestic market. The IBG index is related to the interest of a country to file and exploit Blockchain patents in foreign markets. We observe China and the USA as strong national and international breeding grounds. In particular, Asian countries drive Blockchain inventions. European countries contribute marginally to the Blockchain patent landscape and, together with the USA, are losing ground to Asia. Comparisons to prior work on Blockchain patenting and research patterns partially reflect our results. However, comparisons to AI suggest different patenting and exploitation strategies for Blockchain and AI in China.     

Application Challenges in Fiber and Textile Electronics

Modern electronic devices are moving toward miniaturization and integration with an emerging focus on wearable electronics. Due to their close contact with the human body, wearable electronics have new requirements including low weight, small size, and flexibility. Conventional 3D and 2D electronic devices fail to efficiently meet these requirements due to their rigidity and bulkiness. Hence, a new family of 1D fiber-shaped electronic devices including energy-harvesting devices, energy-storage devices, light-emitting devices, and sensing devices has risen to the challenge due to their small diameter, lightweight, flexibility, and weavability into soft textile electronics. The application challenges faced by fiber and textile electronics from single fiber-shaped devices to continuously scalable fabrication, to encapsulation and testing, and to application mode exploration, are discussed. The evolutionary trends of fiber and textile electronics are then summarized. Finally, future directions required to boost their commercialization are highlighted.     

基于KANO和感性工学的电动滑板车设计研究

目的 融合KANO和感性工学两种分析方法,分析用户需求,并根据消费者需求指导设计一款电动滑板车。从而确保滑板车设计方案符合目标用户基本需求,提升用户满意度。方法 通过调查问卷收集消费者对电动滑板车的使用需求,运用KANO进行用户需求分类,构建电动滑板车消费需求评价体系。运用感性工学分析感性要素与电动滑板车设计的影响关系并提取感性词汇。运用SPSS软件对感性词汇进行评价分析,得出符合消费者需求的感性要素辅助设计过程,使设计的电动滑板车更符合用户的需求和心理。结果 根据分析得到电动滑板车用户需求分类,并结合消费感性需求,确定电动滑板车设计方向,以此进行电动滑板车的设计工作。结论 综合应用KANO和感性工学分析电动滑板车的用户使用需求,研究消费者的感性因素,从目标用户出发,这样有助于更加准确地理解消费者需求,洞察滑板车的设计重点,使设计整体过程更加科学、全面。     

A sustainable city environment through child safety and mobility—A challenge based on ITS?

Our cities should be designed to accommodate everybody, including children. We will not move toward a more sustainable society unless we accept that children are people with transportation needs, and ‘bussing’ them around, or providing parental limousine services at all times, will not lead to sustainability. Rather, we will need to make our cities walkable for children, at least those above a certain age. Safety has two main aspects, traffic safety and personal safety (risk of assault). Besides being safe, children will also need an urban environment with reasonable mobility, where they themselves can reach destinations with reasonable effort; else they will still need to be driven. This paper presents the results of two expert questionnaires focusing on the potential safety and mobility benefits to child pedestrians of targeted types of intelligent transportation systems (ITS). Five different types of functional requests for children were identified based on previous work. The first expert questionnaire was structured to collect expert opinions on which ITS solutions or devices would be, and why, the most relevant ones to satisfy the five different functional requests of child pedestrians. Based on the first questionnaire, fifteen problem areas were defined. In the second questionnaire, the experts ranked the fifteen areas, and prioritized related ITS services, according to their potential for developing ITS services beneficial to children. Several ITS systems for improving pedestrian quality are discussed. ITS services can be used when a pedestrian route takes them to a dangerous street, dangerous crossing point or through a dangerous neighborhood. An improvement of safety and other qualities would lead to increased mobility and a more sustainable way of living. Children would learn how to live to support their own health and a sustainable city environment. But it will be up to national, regional and local governments, through their ministries and agencies and public works departments, to promote, fund, and possibly mandate such systems. It is clear that we need to offer an acceptable level of convenience, efficiency, comfort, safety and security to pedestrians but it is less clear if society will prioritize resources toward this.     

Using a multi-agent system to optimise resource utilisation in multi-site manufacturing facilities

Due to cost economies and better serving the global market, many enterprises expanded their manufacturing environment from a localised, single-site facility to more globalised, multi-site facilities. In order to take advantage of operating multi-site facilities, it is vital to make optimisation decisions of resource utilisation as if these facilities situated across different geographical locations are one integrated facility and take into account of the extended multi-site constraints and variables. This paper proposes a multi-agent system, using its characteristics of autonomy and intelligence, to integrate process planning and production scheduling across different facilities, so as to secure the most efficient and cost-effective plan and schedule to meet the demand. A currency-based agent iterative bidding mechanism is developed to facilitate the co-ordination of agents to achieve the goal. A genetic algorithm is employed to tune the currency values for agent bidding. In this paper, a case study is used for simulation in order to demonstrate the effectiveness and performance of the proposed agent system.     

Recombinant Silk Fiber Properties Correlate to Prefibrillar Self‐Assembly

Spider silks are desirable materials with mechanical properties superior to most synthetic materials coupled with biodegradability and biocompatibility. In order to replicate natural silk properties using recombinant spider silk proteins (spidroins) and wet‐spinning methods, the focus to date has typically been on modifying protein sequence, protein size, and spinning conditions. Here, an alternative approach is demonstrated. Namely, using the same ≈57 kDa recombinant aciniform silk protein with a consistent wet‐spinning protocol, fiber mechanical properties are shown to significantly differ as a function of the solvent used to dissolve the protein at high concentration (the “spinning dope” solution). A fluorinated acid/alcohol/water dope leads to drastic improvement in fibrillar extensibility and, correspondingly, toughness compared to fibers produced using a previously developed fluorinated alcohol/water dope. To understand the underlying cause for these mechanical differences, morphology and structure of the two classes of silk fiber are compared, with features tracing back to dope‐state protein structuring and preassembly. Specifically, distinct classes of spidroin nanoparticles appear to form in each dope prior to fiber spinning and these preassembled states are, in turn, linked to fiber morphology, structure, and mechanical properties. Tailoring of dope‐state spidroin nanoparticle assembly, thus, appears a promising strategy to modulate fibrillar silk properties.     

Modelling joint outsourcing and offshoring decisions

Offshoring and outsourcing have emerged as two most essential and important strategies for the manufacturing firms globally. This has happened due to the relentless forces of competition and globalisation, which has forced modern manufacturing firms to disaggregate themselves and reach for foreign investments, technological inputs through collaboration and cooperation among markets and partners. Outsourcing and offshoring simultaneously has potential to help the firm to meet three strategic goals i.e. ‘efficiency’ through cost minimisation; ‘exploration’ through an access to the right and technologically capable firm vendors/ Suppliers/ players; and ‘exploitation’ from development of global markets. Both outsourcing and offshoring have grown to a great extent either by the number of companies involved or by the number of multiple nations are involved. Hence, addressing both offshoring and outsourcing strategies together can provides value to the supply chain in economical and efficient way. Therefore, this paper is an attempt to model joint outsourcing and offshoring decision integrated with fuzzy-MCDM approaches using fuzzy data to optimise total cost through right selection of suppliers to meet demand of global markets, thus, achieving efficiency, exploration and exploitation. The model addresses qualitative and quantitative criteria in joint decisions and is also illustrated to show the cost effectiveness.     

Static and dynamic axial crushing of spot-welded thin-walled composite steel–CFRP square tubes

Thin-walled metallic tubular components have long been adopted in the transportation industries, where the stable energy absorbing crushing process provides protection to occupants and cargo in the event of a collision. Fibre–epoxy tubes provide superior strength to weight ratios, however brittle failure modes may limit their energy absorbing capacity under large axial deformation. Composite steel–CFRP (carbon fibre-reinforced polymer) tubes are a recent advent, and combine the benefits of the stable, ductile plastic collapse mechanism of the steel and the high strength to weight ratio of the fibre/resin composite, to form a composite tube with high energy absorption capability. In this paper the applicability of steel–CFRP tubes to structures typical to the automotive industry is investigated. Thin-walled square tubes with width to thickness ratios up to 120 are cold-formed and spot-welded from high strength, low ductility steel, and subjected to static and dynamic axial compression. Four different steel tube geometries and two different carbon fibre matrix layouts are investigated, and comparisons are made between static and dynamic crushing, steel and composite steel–CFRP tubes, and regular and low ductility steels. It is shown that the crashworthiness properties of the steel–CFRP tubes exceed those of the steel tubes, however some issues particular to low ductility steels and such steels under impact conditions prove detrimental to the crashworthiness characteristics. Theoretical procedures are developed to design the crashworthiness characteristics of the composite tubes, and are shown to compare well with the experimental results.     

化学计量与环境、资源、健康和可持续发展

文章在数据基础上阐述了化学测量及其量值统一对环境、资源、健康和社套、经济可待续发展的重要性。也介绍了国外化学计量的发展动态。作者呼吁政府和技术机构重视和加强对化学计量的管理和投入．加速完善我国化学计量体系,以满足市场和社会发展的需要。