一种改进的OBS边缘路由器组装算法

在光突发交换(OBS)网络中,通常采用填充无效数据的方法来达到突发包最小包长要求。这种方法不仅造成带宽资源的浪费,并带来边缘处的竞争,增加网络的丢包率。本文提出了一种新的混合组装方案,通过填充低等级业务数据的办法来解决包长太小的问题。模拟仿真结果表明,网络性能可以得到有效改善。     

An Approach for Modeling Small-lot Assembly Networks

A model for estimating the transient performance of assembly networks is presented in this paper. Based on the fundamental assumption that operation start and finish times are related by the multivariate normal distribution, the approach relies upon computational procedures for estimating the correlations between certain operation finishing times. Fundamental properties of these correlations are identified and used to develop a procedure for estimating transient performance. Evaluated in a set of hypothetical test cases, the approach gave estimates which compare favorably with those derived from a simulation model both in accuracy and runtime. The approach is demonstrated as a decision aid in a case study involving material flow planning. Test results indicate that the approach offers unique capability to model transient operations in assembly networks.     

"期间核查"方法的进一步探讨

0引言 随着CNAS—CIJD1：2006《检测和校准实验室能力认可准则》（GB／T27025—2008idtISO／IEC17025：2005《检测和校准实验室能力的通用要求》及JJF1069—2007《法定计量检定机构考核规范》进一步贯彻实施,“期间核查”这一术语在实验室／技术机构专业人员脑海里已不再是陌生的概念了,获得相关资质的实验室／技术机构按照上述标准／规范的要求,每年制定期间核查计划,并按计划实施。     

基于仿真优化方法的混合装配线平衡

针对混合装配线平衡问题传统求解方法的局限性,提出采用仿真优化方法求解该问题。基于最小化工作站和仿真优化方法,分别建立以均匀化各个工作站平均负荷和瞬时负荷为目标的数学模型和仿真模型,并设计了遗传算法作为优化算法。根据仿真优化的原理构建了仿真优化系统并针对系统运行费时的特点,提出了相应的改进方法。通过实际例子验证了方法的可行性。     

桥梁结构多测组振型融合的两阶段快速贝叶斯方法研究

桥梁振动实验常需进行分组多次测试,如何从各测组数据中准确识别频率、阻尼比、局部振型,进而将局部振型组装成整体振型至关重要.结构模态分析过程不可避免地受到测试噪声和模型误差的影响,引入贝叶斯方法进行模态参数识别和振型融合的不确定性量化分析具有重要意义.提出桥梁结构多测组振型融合的两阶段快速贝叶斯方法.第一阶段采用快速贝叶...     

利用Petri网求解U型装配线平衡问题

提出了一种基于Petri网的启发式算法用于求解第一类U型装配线平衡问题,算法利用Petri网的可达分析和托肯的移动来决定可分配的作业元素,并按照最小化工作站空闲时间原则从前向后和从后向前两个方向同时分派作业元素到工作站。算法编程简单,可用于快速求解大规模问题。通过对大量问题集的测试验证,说明了算法的有效性。     

Improving the Integrity of Pharmaceutical Sterility Testing: A New Robotic Approach

Abstract

Concern over the occurence of false positives within the sterility testing process has been and will continue to be of grave concern to pharmaceutical manufacturers. To date, very few truly effective solutions to this problem have been offered, while the FDA becomes ever more stringent over false positive results and second phase testing.

A new robotic system for sterility test applications is described, which completely isolates the actual test area from human operators, and thus reduces substantially any possibility for false positives. The configuration utilizes the USP-preferred membrane filtration method, and uses the Millipore Steritest filtration chambers as its “output” for incubation. The system allows a technician to simply place product to be tested in an input station, mount the Steritest cannisters in designated sockets, then remove the empty containers and filled cannisters post-processing and incubate. This new method allows for the testing of a variety of different sample containers, including a range of vial sizes, ampoules, and pre-filled syringes.

The test methodology will be described in detail, including an in-depth look at the actual application procedure and a discussion of major system components and overall system configuration.     

A Novel Approach for Micro-electro-mechanical System(MEMS) Vacuum Packaging

MEMS vacuum packaging is now the impedimeut of the MEMS appliance in some specified fields. The major problem of current packaging approach is that the packaging process cannot meet the requirement of the ultra low leak. But the process cannot be improved with the existing technology. We propose a novel approach for MEMS vacuum packaging which can remarkably lower the leak rate. This paper analyzed the vacuum maintaining time of the vacuum packaging and compared the current design and new packaging method.     

A Novel Nonlinear Acoustic Health Monitoring Approach for Detecting Loose Bolts

To date, sensors have been the inevitable component of structural health monitoring (SHM) systems. Typically, sensory signals are digitized, processed by computers, and then the information is presented to the operator with plots or warnings depending on the sophistication of the system. This study proposes a novel nonlinear acoustic health monitoring (NAHM) approach for detection of loose bolts, which can work with and without any sensors. The structure is excited with bitonal excitations, which their difference is in the audible range. When the bolts are well tightened, the structure remains silent. But, the structure creates audible sound or verbal warnings in the presence of one or more loose bolts. There is no need for sensor(s), A/D converters or computers between the operator and the structure. However, it is also possible to attach a piezoelectric sensor or to use a microphone/sound level meter for further analysis of the structure’s response. The feasibility of the concept was demonstrated by detecting the loose bolt in a bolted plate system. For demonstrating the industrial potential of the proposed NAHM system, the concept was implemented for two simple washers held with nuts and bolts. Additionally, the intensities of the audible alarms were studied at different torque levels. The proposed NAHM may be used as a low-cost sensor-free SHM or as a backup for conventional nonlinear SHM systems.     

A Novel Primal-mixed Finite Element Approach for Heat Transfer in Solids

A new reliable primal–mixed finite element approach for the heat transfer analysis in solids, is examined in detail. The essential contribution is that both variables of interest, temperature and heat flux, are calculated simultaneously from the same system of finite element equations. In addition, as a novelty, continuity of the trial and test heat flux functions is enforced, to avoid the need for some a posteriori heat flux smoothing technique. In order to minimize the accuracy error and enable introduction of the flux constraints, tensorial character of the present finite element equations is fully respected. The proposed finite element is subjected to low and high order convergence and efficiency tests in steady state and transient heat transfer analysis, which enlighten its solvability, stability, accuracy and effectiveness, i.e. its reliability.     

大型水轮机叶片快速检测的新方法

为解决大型水轮机叶片尺寸检测这一行业性难题,实现对叶片型面外型尺寸的快速检测,提出了一种基于视觉测量技术的新方法.该方法以摄影测量原理为理论基础,首先在物体表面待测位置粘贴标志点,然后从不同角度拍摄一组照片,作为测量的原始数据输入计算机中进行解析处理.在测量软件中通过对照片组进行图像检测,识别出各张照片中标志点并定位其中心,匹配同名标志点,最后根据标志点的多个二维坐标重建出对应物体点的三维坐标,从而实现对被测对象的数字化建模和测量.现场实验表明,与传统的水轮机叶片检测方法相比,该方法具有工作量小,速度快,成本低,容易实现在线检测,并且不易受现场灰尘、振动、湿度和温度变化等外界因素的干扰.     

三维CAD实验课程体系建设

随着先进设计和制造技术的推广应用,机械学科内涵发生了很大变化,传统的设计与绘图教学模式和手段已不适应现有的要求.介绍了机械类专业本科课程改革方案,提出基于三维的CAD实验课程体系建设,设置了一系列不同层次的CAD培训课程,教学内容和机械学科的课程设置相关联,循序渐进.通过课程学习,使学生建立基于三维的工程设计概念,培养工程素质和创新设计能力.     

液压控制集成块的产品模型化--提高工程设计效率的一条途径

 为了提高效率,专用的CAD系统(例如液压控制集成块的设计系统)应能扩展到整个系统的设计和检验。本文介绍这样的一个设计系统,它是基于各种液压元件产品模型各种数据的处理,其中不仅处理几何尺寸,而且还包括为进一步扩展功能所需要的技术上和管理上的各种信息。     

光学对点器的检校方法探讨

本文通过分析光学对点器的光学结构,说明了检修经纬仪或全站仪必须在两个不同距离上检校光学对点器的必要性.     

箱体零件CAD／CAPP／CAM集成系统的研究与实践

在ＣＩＭＳ环境下，针对箱体零件ＣＡＤ、ＣＡＰＰ、ＣＡＭ信息集成的功能需求，在基于特征的箱体零件信息模型、工艺计划模型与服务于工艺设计的制造环境模型的支持下，开发出了特征造型，工艺设计及加工过程仿真与ＮＣ编程等子系统，从而完成了一个集成化的箱体零件ＣＡＤ／ＣＡＰＰ／ＣＡＭ系统。     

基于RBF网络的光学字符提取与识别新方法

提出了一种新的基于统计与模糊隶属度的光学字符特征提取方法,可以快速准确地识别受噪声污染的光学字符.相比传统算法,本文方法的特征空间区分度更高,最小类间距离扩大33.2%以上.应用在径向基函数(Radical Basis Function,RBF)神经网络中,在字体字号变化且有背景噪声污染的影响下,识别率高达99%以上,且相比直方图投影法提速75%.理论分析与实验结果表明,与传统方法相比,该算法抗噪能力更强、模式区分度更高、时空复杂度更低,更简约、更全面地覆盖了字符的特征,应用范围广.已应用于实际系统,取得很好的实验结果.