异构环境通用CSCW系统模型与体系结构的设计与实现

提出基于MVC设计模式,适用于多种应用环境(C/S、B/S、Ria等)及多种网络环境(Client-Server、P2P、Ad Hoc等)的CSCW系统模型.该系统模型通过对MVC设计模式中Model层及Control层的分离,规范了系统模块及关系,解决了异构环境下CSCW系统架构统一的难题.本文给出了通用CSCW系统模型在各种异构环境中的体系结构设计,由于各体系结构设计具有相同的模块划分及相似的模块间关系,增加了混合异构环境下系统模块的复用率,提高了开发效率.     

嵌入式电阻点焊控制器

本文根据ARM芯片和UC/OS-Ⅱ实时操作系统的特点,设计了一个以LPC2292为核心的嵌入式电阻点焊控制系统.该系统根据点焊控制系统的要求,分为不同的任务模块,各模块由嵌入式实时操作系统UC/OS-Ⅱ统一调度.研究表明,该嵌入式系统在提高系统实时性、可靠性及可读性的同时,降低了系统的设计周期,节省了系统开发和维护的费用.     

基于PCIe总线的卫星导航信号传输系统设计

为了满足高精度软件接收机对卫星导航中频信号传输系统的新要求,设计了一种基于PCIe总线的传输系统.该系统以Virtex-5 FPGA为核心控制器件,以DMA方式通过4通道PCIe接口传输导航卫星数据.详细介绍传输系统AD模块、DMA控制模块、中断模块等核心模块的FPGA实现方法.经过测试与验证,系统读写速率分别达到了800 MB/s和650 MB/s,可以满足不同层次导航软件接收机对原始导航数据的需求.     

基于C MEX S函数的盲源分离仿真研究

在分析基于最大信噪比盲源分离算法数学模型的基础上,利用C语言编写S函数,并提出了基于最大信噪比盲源分离系统仿真建模的方法.在Matlab/Simulink中,构造C MEX S函数的简化结构,建立独立功能的模块(如中心化模块、白化处理模块、基于最大信噪比分离模块及后处理的排序模块等),再对各个功能模块进行有机的结合,从而搭建基于最大信噪比盲源分离系统仿真模型,为提高复杂系统模型的仿真速度,以及与仪器仪表结合的设计与调试提供了新的思路.仿真结果证明了采用C MEX S函数方式搭建模型的快速性与有效性.     

水下分散自重构系统设计

研究一种新的水下系统设计概念,水下分散自重构系统.该系统由数量不定的少数几类相似模块组 成,通过模块之间的连接和分离,可以实时改变系统构形.通过模块的协调变形,可以实现不同的运动方式.开发了 一个基本的样机系统,称为USS.USS目前只包括一类模块,可以实现2 种平面基本构形和2种空间基本构形.由于 具有浮力调节能力,可以通过平面构形实现海洋水体空间机动,以及海底和水下结构物中的运动.     

AOTF近红外光谱仪信号源设计

在声光可调滤光器(AOTF)近红外光谱仪系统中,稳定的射频驱动信号源是AOTF实现分光功能的关键.本文根据近红外光谱分析所需的波长范围,利用直接数字频率合成(DDS)技术,设计了驱动AOTF所需的射频信号源.系统包括单片机控制模块、DDS信号发生模块、滤波电路、功率放大模块四部分.经实验测试,系统可在80～150 MHz频段内任意频点输出稳定的正弦信号波形,相对误差在0.45％以内,功率为1W,满足AOTF的工作要求(对应输出波长范围900～1 700 nm).     

一种用于乳腺疾病检测的新型近红外成像系统

基于近红外光的乳腺癌诊断技术一直是生物医学工作者的研究热点,研制一种用于监测和处理乳腺组织近红外透射光的成像系统。系统选用760nm和850nm两种近红外光分时透射乳腺组织,经同步采集、图像配准、信号分离滤波后计算功率谱、互相关曲线和互相关系数等以研究透射光的频域特性。着重介绍该成像系统的原理以及软硬件模块的设计和实现。     

基于Asp.net的权限系统的设计与实现

在Web系统开发中,由于系统资源的差异性和对权限管理要求的复杂性导致产生一些问题,如同一个系统中不同的子业务设置不同的权限,从而需要对不同的子业务模块编写权限控制代码,而这些代码存在着重复设计冗余编写以致降低了Web系统的开发效率.针对上述问题,在ASP.net中已有的基于角色的访问控制部分上,结合RBAC授权模型进行系统扩展,设计并实现了一个可以在中小型Web应用系统中通用的权限管理系统子模块.该模块采用三层结构,实现了权限控制和业务的分离,可以很方便地在其他Web系统中使用.     

基于JSP的网络通讯薄系统设计

利用JSP(Java Server Page)和JavaBean等技术,选用MS SQLserver作后台数据库,Tomcat5.5作服务器,eclipse作开发环境实现了一个B/S(浏览器/服务器)模式的网络通讯薄系统,并讨论了系统的设计、具体实现和jsp开发中一些常用的技术和技巧.该系统具由用户管理模块、记录浏览模块、记录添加模块、记录查找模块、记录修改模块和记录删除模块组成.读者通过少量的改动就可以将该系统加到自己的网页中,从而通过登录系统来查看和管理通讯薄系统.     

基于数字证书的通用权限管理的设计与实现

在基于数字证书的应用系统开发中,针对不同的业务系统的权限管理,都要重新编写权限控制代码,造成人力资源浪费的问题。分析并比较了基于数字证书的权限管理与传统用户名/密码方式认证的权限管理区别,提出利用功能向量码的方法实现一种通用的基于数字证书的权限管理模块。利用该模块,只需替换验证签名模块,无需再编写代码,就可以应用到不同的基于数字证书认证的系统中,从而实现权限控制和业务的分离。本系统已经开发并在多个系统中使用,应用效果良好。     

基于ADAM的平膜拉丝机远程监控系统

塑料平膜拉丝机是将颗粒状的塑料原料经过加热、挤压、自然沿垂、拉伸、切割、收丝等工序加工成用于塑料编织袋编织的塑料细丝，其工艺过程对温度、拉伸速度有着严格的要求。研华ADAM远程模块是基于RS-485总线形式的远程监控模块，具有工作稳定、传输距离远等特点，利用远程模块数据检测与组态王组态软件实现的塑料平膜拉丝机远程监控系统较好地满足了各项工艺指标的要求。     

Spatial orientation and topology optimization of modular trusses

Modularity in structural engineering offers significant cost advantages since identical components can be mass-produced in high quality-controlled facilities. While prior research has investigated the optimization of modular structures, this work is limited to the module topology periodicity, leading to solutions where some structure parts remain inefficiently used. This paper proposes a continuum-based formulation for optimizing simultaneously the module topology and spatial orientation in modular trusses. The numerical difficulties associated with the module rotations in the optimization formulation are identified, and properly handled by a novel topology-based rotation representation using group theory. A relaxation strategy based on complementary constraints enables the continuous integration of the module rotations in a lower-bound plastic design formulation (or fully stressed design). Case studies involving high density ground structures demonstrate that it is able in the worst case to retrieve the results obtained by imposing the module orientation a priori, and to improve the optimized design when freedom on the rotations is considered.     

New Applications

Varian Series 620 minicomputers are controlling chemical reactors at three large, new plants that manufacture poly-vinyl chloride (PVC), an industrial plastic used in pipe and pipe fittings, packaging, and a variety of consumer goods.     

全数字化PET系统时间信号基准模块设计

为了满足为全数字化PET（正电子发射断层扫描仪）系统中前端电子学模块提供时间信号基准的时钟信号的要求,采用FPGA和AD9516-4芯片设计了一种时间信号基准模块。针对时间信号基准的要求,提出了通过参考基准频率由锁相环产生高频信号,同时利用分频器实现了对高频时钟信号的分频,并用LVDS（低电压差分信号）模式对生成的多路时钟信号进行输出,从而获得了多路频率、相位、幅值均相同的同步时钟信号的方法。相比于其他方法实现的时钟分配模块,本方法具有高精确度,低功耗和高稳定性的特点。该模块已经在全数字化PET系统中使用,验证了该模块具有高精确度和高稳定性的特点。     

融合残差和对抗网络的跨模态PET图像合成方法

针对现有跨模态图像合成方法不能很好地捕获人体组织的空间信息与结构信息,合成的图像具有边缘模糊、信噪比低等问题,提出一种融合残差模块和生成对抗网络的跨模态PET图像合成方法。该算法在生成器网络中引入改进的残差初始模块和注意力机制,减少参数量的同时增强了生成器的特征学习能力。判别器采用多尺度判别器,以提升判别性能。损失函数中引入多层级结构相似损失,以更好地保留图像的对比度信息。该算法在ADNI数据集上与主流算法进行对比,实验结果表明,合成PET图像的MAE指标有所下降,SSIM与PSNR指标有所提升。实验结果显示,提出的模型能很好地保留图像的结构信息,在视觉和客观指标上都能提高合成图像的质量。     

Preparation of PCLT/P(VDF-TrFE) pyroelectric sensor based on plastic film substrate

Nanosized lead titanate doped with calcium and lanthanum (PCLT) powder obtained by the sol–gel method was homogeneously mixed with vinylidene fluoride-trifluoroethylene [P(VDF-TrFE)]. The nanocomposite PCLT/P(VDF-TrFE) film was used as the sensing film for pyroelectric sensors, whose detective merit was about 22.4% higher than that of sensors using pure P(VDF-TrFE). A 35 nm ITO film was deposited as the bottom electrode on PET plastic film substrate, on which PCLT/P(VDF-TrFE) was prepared by spin-coating, and Ni–Cr film was chosen as the upper electrode. The PET plastic film substrate could effectively decrease the thermal conductivity of the element and the ITO bottom electrode could reflect the infrared irradiation. The voltage responsivity was increased and the thermal fluctuation noise of the pyroelectric element was decreased significantly. The experimental results indicated that the specific detectivity of PCLT/P(VDF-TrFE) pyroelectric sensors based on PET film substrate reached 3.4E7 cm Hz^1/2 W⁻¹, more than two orders of magnitude higher than that of the sensors on bulk silicon substrate formed under the same conditions.     

ф400聚氯乙烯塑料管在法库给水工程中的应用

Ф400大口径聚氯乙烯塑料(UPVC)管首次应用在给水工程中,笔者在设计和施工中积累了一些宝贵的经验。分析了UPVC管的特点、设计及在实践中的应用,对给水管材的选用有一定的指导作用。     

Magnetic lithography for servowriting applications using flexible magnetic masks nanofabricated on plastic substrates

Magnetic lithography (ML) is a process qualitatively analogous to contact optical lithography which transfers information from a nanopatterned magnetic mask (analog of optical photomask) to magnetic media (analog of photoresist), and is interesting for applications in instantaneous parallel magnetic recording, in particular for servowriting applications. The magnetic mask consists of nanopatterned magnetically soft material (FeNiCo, FeCo) on a thin flexible plastic substrate, typically Polyethylene teraphtalate (PET) or polyimide. When uniformly magnetized media is brought into intimate contact with the magnetic mask, an externally applied magnetic field selectively changes the magnetic orientation in the areas not covered with the soft magnetic material. Flexible substrate of the magnetic mask offers superior compliance to magnetic media which is likely to have imperfect flatness and surface particulate contamination. We discuss nanofabrication challenges of magnetic masks on plastic substrates, including electron beam lithography, electroplating and lift-off processing on the nanometer scale, adhesion of metal thin films on PET and polyimide substrates, and release of plastic films from rigid substrates used during the processing. We present results on fabricated magnetic masks, magnetic force microscopy images of the magnetic transition patterns and disk spinstand tests of servowritten patterns.     

A novel CACD/CAD/CAE integrated design framework for fiber-reinforced plastic parts

This work presents a novel CACD/CAD/CAE integrated framework for design, modeling, and optimization of fiber-reinforced plastic parts, which can greatly enhance the current design practice by realizing partial automation and multi-stage optimization. To support this framework, a new heterogeneous feature model (HFM) has been developed to model the fiber-reinforced objects and to be transferred between engineering modules. To be specific, the CACD (computer-aided conceptual design) module employs the level-set structure and material optimization to produce the initial design with thickness control, and also the initial HFM; the CAD (computer-aided design) module allows manual editing on the HFM to reflect various design intents; then, the injection molding CAE (computer-aided engineering) simulates the manufacturing process, and the response surface method (RSM) is applied to optimize the process parameters of gate location, injection flow rate, mold temperature and melt temperature, to approach the manufactured fiber orientation distribution close to the optimized result produced by the CACD module; besides, the structural analysis CAE module generates the mechanical performance result to support the CACD module, as well as to validate the final design. By applying this framework, the final structural design including the fiber orientation distribution, will perform better in mechanical properties, and consume less matrix and fiber materials; besides, the design maturity can be approached in shorter time. To prove the effectiveness, a plastic gripper design will be comprehensively studied.