工业现场PLC控制系统抗干扰设计与实现

在现今的工业生产现场,PLC控制系统是最为常见的系统之一,也是最为重要的操作系统,关系到整个生产作业的稳定性和安全性。为保证生产活动正常运行需要控制PLC控制系统的正常运作,研究在系统运行中可能出现的干扰因素,其中主要分为外部、内部两个方向。本文将从PLC控制系统可能产生的干扰来源进行分析,设计出对于不同环节出现的干扰现象的解决办法。从硬件设计入手,研究抗干扰的措施。通过实验分析,经过抗干扰措施后的PLC系统的稳定性和抗干扰程度。实验结果表明,经过以上方法改良后PLC系统可以很大程度上实现干扰现象最小化。     

Modeling the glucose regulatory system in extreme preterm infants

Background

Premature infants represent a significant proportion of the neonatal intensive care population. Blood glucose homeostasis in this group is often disturbed by immaturity of endogenous regulatory systems and the stress of their condition. Hypo- and hyperglycemia are frequently reported in very low birth weight infants, and more mature infants often experience low levels of glycemia. A model capturing the unique fundamental dynamics of the neonatal glucose regulatory system could be used to develop better blood glucose control methods.

Methods

A metabolic system model is adapted from adult critical care to the unique physiological case of the neonate. Integral-based fitting methods were used to identify time-varying insulin sensitivity and non-insulin mediated glucose uptake profiles. The clinically important predictive ability of the model was assessed by assuming insulin sensitivity was constant over prediction intervals of 1, 2 and 4 h forward and comparing model-simulated versus actual clinical glucose values for all recorded interventions. The clinical data included 1091 glucose measurements over 3567 total patient hours, along with all associated insulin and nutritional infusion data, for N = 25 total cases. Ethics approval was obtained from the Upper South A Regional Ethics Committee for this study.

Results

The identified model had a median absolute percentage error of 2.4% [IQR: 0.9-4.8%] between model-fitted and clinical glucose values. Median absolute prediction errors at 1-, 2- and 4-h intervals were 5.2% [IQR: 2.5-10.3%], 9.4% [IQR: 4.5-18.4%] and 13.6% [IQR: 6.3-27.6%] respectively.

Conclusions

The model accurately captures and predicts the fundamental dynamic behaviors of the neonatal metabolism well enough for effective clinical decision support in glycemic control. The adaptation from adult to a neonatal case is based on the data from the literature. Low prediction errors and very low fitting errors indicate that the fundamental dynamics of glucose metabolism in both premature neonates and critical care adults can be described by similar mathematical models.     

基于模糊集合的完整性信任度评估模型

完整性度量是可信计算得以实现的一项重要技术。根据影响操作系统完整性的内核模块、二进制可执行文件等因素,通过定义直接信任度、间接信任度和综合信任度等计算公式构建了一个操作系统的完整性信任度评估模型,该模型利用模糊集合理论将完整性度量化为[0,1]之间的具体数值,并根据隶属函数将操作系统的信任度划分为四个信任等级。该模型改变了原有完整性度量中一致执行、不一致停止的二值状态,为远程验证者提供较为精确的操作系统完整性度量值,提高了系统的可用性。仿真实验结果表明该模型较客观地提供了操作系统的完整性信息。     

无创血糖检测仪的DSP和Android软件系统设计

基于DSP和Android操作平台的处理系统是目前电子产品的应用热点。介绍了无创血糖检测仪系统的硬件结构和软件应用平台,详细阐述了DSP主控芯片的控制流程和Android平台的用户交互模块设计,通过RS232标准接口,实现了无创血糖检测仪系统各模块的串行通信。对16名志愿者进行血糖测试实验,样本测试相关系数为0.863,实验表明,该系统可以控制完成血糖检测和原始数据的存储,无创血糖测试具有可行性。     

Vague值与Vague集的多测度相似度量

针对Vague值(集)相似度量问题,指出了采用单一测度构造Vague值(集)相似度量的不足,根据不同测度表现的不同相似性度量特点,提出了两种由距离测度、未知度测度和熵测度三种测度结合的Vague值(集)多测度相似度量,并给出了相应的定义和性质.多测度相似度量体现出了多特征度量相似性的特点,若距离与熵测度失效,未知度测度仍能发挥作用,而距离与熵测度度量结果的综合,则进一步提高了分辨力.实例验证了该多测度相似度量的有效性和优越性.     

Weighting Restriction for Intravenous Insulin Delivery on T1DM Patient via $H_{infty}$ Control

A weighting restriction with frequency components is proposed for the insulin delivery on Type 1 Diabetics Mellitus (T1DM) towards the control of the blood glucose level. The weighting restriction is stated from a model of healthy subjects which includes a rate for insulin delivery. The frequency components are incorporated via a transfer function from the plasma glucose to the free-plasma insulin such that a H _infin-based controller is designed. In this way, the control synthesis involves the frequency components on which a healthy pancreas delivers insulin for the glucose homeostasis. In order to test controller performance, a dynamical model of an actuator is also included in the closed-loop system to add its effects in the closed-loop evaluation of the H _infin -based controller. The actuator is a pump to deliver of an insulin infusion according with the rate computed by the controller. Note that the contribution is particularly focused on T1DM; however, the inclusion of weighting restriction can be used also onto critical care conditions.     

一种基于支持系数的Vague集（值）相似度量新方法

对现有的一些Vague集（值）相似度量算法进行分析,指出了这些方法在计算相似度方面的片面性与局限性。通过对Vague集中元素的未知度进行分析,并引入支持系数来调节未知信息对真、假隶属度的影响,从而提出了新的Vague集（值）相似度量算法,通过模式匹配的实例验证了该算法的实用性。通过与以往的一些算法进行比较,充分证明了新算法的合理性与有效性。     

Combining statistical, rule-based, and physiologic model-based methods to assist in the management of diabetes mellitus

Self-monitoring of capillary blood glucose is used by most patients with insulin-dependent diabetes mellitus as a means of assessing metabolic control. Therapeutic interventions are based on retrospective analysis of glycemic response to various factors, with insulin and diet playing the key roles. We describe a computer system being developed for intelligent automated analysis and interpretation of data relevant to glycemic control. CADMO (Computer-Assisted Diabetes Monitor) is intended to assist health care professionals with the management of patients with insulin-dependent diabetes. It takes as input glucose values and insulin doses collected via a memory meter by the patient over a period of several weeks. Rule-based logic, statistical methods, and a physiologic model of insulin pharmacokinetics and glucose dynamics are used to help detect meaningful patterns and trends in glucose and insulin data and to suggest approaches for optimizing insulin regimens.     

发电厂集散控制系统的抗干扰技术研究

发电厂存在的各种干扰对发电厂中的电子设备,特别是对集散控制系统的安全运行造成了一定的危害。本文综合分析了发电厂常见的干扰,并针对性地提出了一些增强系统抗干扰性能的技术措施。     

A model-based sliding mode control methodology applied to the HDA-plant

A sliding mode control methodology using output information is demonstrated in application to the HDA-plant, a plant for production of benzene. This process is a highly integrated, non-linear large scale process with non-minimum phase and relative degree zero characteristics. The non-linear control law is designed on the basis of a linear observer-based control system. The non-linear control law uses the states of the linear observer. The performance in the sliding mode is determined by a linear stable sub-manifold of the linear closed loop control system chosen via a robust pole selection scheme. The sliding mode control is optimized to operate in a wide operating region.     

有效防御可执行恶意代码的访问控制模型

可执行恶意代码严重危害操作系统的安全,它通过进程实现对系统造成危害,能否控制进程的安全是可执行恶意代码防御中的关键问题。该文以安全操作系统的访问控制思想为基础,根据可信计算的思想和原则,提出一个防御可执行恶意代码体系中的URPP访问控制模型。该模型以进程作为核心,对进程启动进行可信度量以及最小权限的约束。实践证明,URPP模型能够有效地抑制可执行恶意代码对系统造成的危害。     

Feedforward dynamics for the control of articulated multi-limb robots

We describe a general approach for using linearizing feedforward control inputs for large degree of freedom (dof) multi-limb robots operating in scenarios involving motion and force constraints, and under-actuated degrees of freedom arising from the task and the environment. Our solution is general and has low computational cost needed for real-time control loops. It supports the tuning of the feedforward term to meet multiple task objectives. Being structure-based, it is able to easily accommodate changes in motion and force constraints that often occur in robotics scenarios.     

基于视频确认的变电站顺控操作系统

目前变电站的顺控操作都需要人为干预,工作效率低,自动化程度不高。由于电网对变电站顺控操作的准确性要求高,目前顺控操作防止误操作机制单一,因此无法满足电网对安全性的高要求。本文在原有防误逻辑的基础上提出一种通过模板特征匹配视频分析算法来视频识别设备当前运行状态的方法,对顺控操作中刀闸、翻字牌等设备状态进行高精度可靠识别,实现了顺控操作不同源信号双确认,增加了防止误操作的途径,大大降低了顺控操作中系统误判率,也减少了顺控操作人工参与,提高了变电站顺控操作的工作效率和自动化程度,为电网安全运行提供了保障。     

The generalized Dice similarity measures for Pythagorean fuzzy multiple attribute group decision making

The Pythagorean fuzzy set (PFS) is characterized by two functions expressing the degree of membership and the degree of nonmembership, which square sum of them is equal or less than 1. It was proposed as a generalization of a fuzzy set to deal with indeterminate and inconsistent information. In this study, we shall present some novel Dice similarity measures of PFSs and the generalized Dice similarity measures of PFSs and indicates that the Dice similarity measures and asymmetric measures (projection measures) are the special cases of the generalized Dice similarity measures in some parameter values. Then, we propose the generalized Dice similarity measures-based multiple attribute group decision-making models with Pythagorean fuzzy information. Then, we apply the generalized Dice similarity measures between PFSs to multiple attribute group decision making. Finally, an illustrative example is given to demonstrate the efficiency of the similarity measures for selecting the desirable ERP system.     

Control of high-resolution electrohydrodynamic jet printing

This paper discusses the development of a sensing and feedback-feedforward control system for Electrohydrodynamic jet (E-jet) printing. E-jet printing is a nano-manufacturing process that uses electric field induced fluid jet printing through nano-scale nozzles for achieving better control and resolution than traditional jet printing processes. The printing process is controlled by changing the voltage potential between the nozzle and the substrate. However, it is difficult to maintain constant operating conditions such as standoff height during a run of the printing process. The change in operating conditions results in fluctuating jet frequency and droplet diameter. For stabilizing the jetting frequency across a single run, a two degree of freedom (2 DOF) control algorithm is implemented. The feedforward voltage signal is used to compensate for repeatable changes in the operating conditions and is obtained using an Iterative Learning Control (ILC) algorithm. The feedback controller compensates for uncertainty in jetting operating conditions. The jetting frequency is determined in real time by recording electric current pulses when ink droplets are released from the nozzle. This frequency measurement is then used to control the voltage profile across a run to compensate for changing operating conditions. Experimental results are presented to validate the proposed control method.     

A simple measure of confidence for fuzzy land-cover classification from remote-sensing data

Representing the quality of thematic maps derived from remote-sensing image classification is important in assessing its fitness for use. Conventional approaches to represent the quality in terms of accuracy need information from the reference data at the same scale. Error-prone or dubious reference data may have an impact on the assessment of quality. Therefore, measures that complement the conventional accuracy measures are required to represent the quality. Uncertainty and confidence are such measures that do not require reference data. Few studies have been attempted to derive pixel-level confidence. However, these measures are not widely adopted by the remote-sensing community due to their limitations. In this article, a simple measure of confidence is derived to represent the quality of fuzzy classification. To derive the confidence value for a pixel, two values, viz. first highest class membership value as evidence and an associated degree of certainty, are required. When the difference between first and second highest membership values is used as degree of certainty in the proposed approach, the confidence measure derived is equal to the complement of existing measure of uncertainty, viz. confusion index in difference form.     

基于ARMA预测的无线监控系统可靠传输机制

无线监控网络易受衰减、多径、盲区等不利因素影响,经常出现局部节点负载过大而导致拥塞现象的发生,导致数据可靠传输得不到保障.从拥塞控制角度,提出了一种基于拥塞预知的改进的拥塞控制算法.该算法基于主动避免拥塞的设计思想,在选取路由时考虑链路质量指标LQI,并依据ARMA预报算法获得未来时刻的网络流量预报值,由此判断节点的拥塞程度以便预先采取措施,最终实现拥塞自适应控制.实验结果表明,该算法能提升无线监控系统数据传输的可靠性,并能显著提高吞吐量.     

The THUDSOS Distributed Operating System

The THUDSOS is a distributed operating system modeled as an abstract machine which provides decentralized control,transparency,availability,and reliability,as welol as a good degree of autonomy at each node,that makes our distributed system usable.Our operating system supports transparent access to data through network wide filesystem.The simultaneous access to any device is discussed for the case when the peripherals are treated as files.This operating system allows spawning of parallel application programs to solve problems in the fields,such as numerical analysis and artificial intelligence.     

Vague集相似度量的新方法

根据区间相似性的原理,指出影响Vague集相似性度量的4个因素,指出了现有方法的不足,提出了一种新的Vague集相似性度量方法,证明了它满足若干准则。通过例子证明了方法的有效性和优越性。     

Sensitivity analysis for simulation-based decision making: Application to a hospital emergency service design

An increasing concern of decision makers when dealing with system design is preparation for a wide range of potentially uncertain operating conditions. This paper provides a novel multiobjective approach for simulation-driven decision making that accounts for not only the conventional average system performance indices, but also (i) upper-tail, or extreme, values of these indices, and (ii) measures of their sensitivity to uncertainty in model parameters. The proposed approach is applied to a hospital emergency department service design case study wherein different design alternatives are compared using total time-in-system performance metric under multiple uncertain operating conditions.