基于Matlab的SMB色谱分离过程计算机仿真研究

针对考虑因素全面的SMB综合速率模型,采用有限元方法和正交配点法分别对柱向和吸附剂颗粒径向模型进行离散化,利用Matlab ODE求解器对SMB过程进行了数值求解,并编制了SMB过程仿真软件。在此基础上进行了一个SMB分离实例仿真,分析了切换时间和流量变化对分离性能的影响,验证了SMB过程分离性能的参数敏感性,提出了对系统实施先进控制的必要性。     

Neural network-based identification of SMB chromatographic processes

In this contribution, the identification problem for the control of nonlinear simulated moving bed (SMB) chromatographic processes is addressed. For process control the flow rates of extract, desorbent, and recycle of the SMB process, and the switching time are the manipulated variables. But these variables influence the process in a strongly coupled manner. Therefore, a new set of input variables is introduced by a nonlinear transformation of the physical inputs, such that the couplings are reduced considerably. The front positions of the axial concentration profile are taken as model outputs. Multilayer feedforward neural networks (NN) are utilized as approximating models of the nonlinear input–output behavior. The gradient distribution of the model outputs with respect to the inputs is used to determine their structural parameters and the network size is chosen by the SVD method. To illustrate the effectiveness of the identification method, a laboratory scale SMB process is used as an example. The simulation results of the identified model confirm a very good approximation of the first principles models and exhibit a satisfactory long-range prediction performance.     

Modeling of chromatographic separation process with Wiener-MLP representation

Dynamic input–output-models have been identified for columns of an industrial sequential ion-exclusive chromatographic separation unit. Models are aimed at describing motion and form transformation of the fronts of different substances in the columns so that changes in “limit cycles” dynamics and drifts to undesired disturbed states could be observed on-line with model based simulations. The model structure has been innovated on the basis of classical Wiener representation, in which nonlinear dynamic system is described with a combination of linear Laguerre dynamics and static nonlinear mapping. The static mapping is realized here with MLP-type neural network. A separate delay model is needed for describing the movement of the front. The delay time adapts on variations of the process flow rate. Form transformation of the front is described with a dispersion model, which is smoother type Wiener-MLP model. Forward and backward Laguerre presentations are calculated with Laguerre filters. These Laguerre presentations are mapped to the output with a neural network. Dynamics of “salt” and two important compounds have been modeled on the basis of analyzed samples, which were taken in a factory experiment during normal production. A priori information about the process dynamics can be included in the dispersion model by choosing a suitable Laguerre parameter, but otherwise representativeness of the identification data determines validity of the model.     

苯丙氨酸模拟移动床色谱分离的建模和优化

根据模拟移动床（SMB）的发展现状和操作流程要求,对模拟移动床色谱分离的工艺流程进行了重新设计,使得系统的整个操作流程更为简单实用。用BP神经网络对苯丙氨酸模拟移动床的色谱分离过程进行了建模,用实数编码的遗传算法对分离参数和操作条件进行了优化,并在实际生产中得到应用,使产品的纯度和回收率都得到了较大的提高。该工艺具有分离效果好等优点,现已在江阴某公司成功投入使用,苯丙氨酸的纯度和回收率都达到了98％以上。     

间歇结晶过程建模和动态模拟

间歇结晶过程广泛应用于精细化工、医药、生物等过程,该过程的模拟将对产品质量和过程控制具有重要作用。本文建立了间歇结晶过程数学模型。该模型是一个包含双曲型偏微分方程(粒数衡算方程)及微分-积分方程的复杂方程组,其较强的非线性使得难以求得解析解。本文用数值方法计算了粒数密度分布函数、过饱和度、成核与生长速率等重要的过程参数,定义并计算了过程的产品质量评价指数。定量模拟了晶种对结晶过程的影响,以及结晶过程中成核和生长的竞争关系,同时,对上述现象和规律进行了理论分析。     

Modeling and simulation of asymmetrical three-roll bending process

Asymmetrical three-roll bending is one of the three-roll bending processes widely used in metal forming due to its simple configuration. Modeling and simulation of the process based on finite element analyses has great interests to industrial practices. This paper deals with the prediction of the position of the lateral roll during cylindrical roll bending. In the numerical model, the rolls are assumed to be rigid bodies and the plate is assumed to be made of elasto-plastic material, with a bilinear material model corresponding to the results from tensile tests. Shell elements are applied to the plate and automatic node-to-surface contacts are selected for the interfaces between the plate and the rolls. The nonlinear equations are resolved by fully integrated Belytschko–Tsay shell formulation under the well-known ANSYS/LS-DYNA environment with explicit time integration. The positions of the lateral roll predicted by the numerical simulations agree well with experiments.     

SMB色谱模型数值计算的时空守恒元解元方法

为了探寻出一种求解SMB色谱模型的快速数值求解方法,并试图通过比较得出时空守恒元/解元(CE/SE)方法确实是快速数值求解方法,因而采用该方法对SMB色谱模型进行数值求解,并在数值方法的计算效率和精确度两个方面与有限差分法和正交配置有限元法进行了比较,最终得出了CE/SE方法是具有高计算效率和高精确度特性的快速数值求解方法.通过两个实例的模拟仿真,结果表明了该方法在高计算效率和高精确度方面的优越性.     

基于过程模型随机仿真的TDD模块选取建模方法研究*

为了帮助项目经理合理选择TDD实施模块,基于进程代数方法对测试驱动软件开发过程和非测试驱动软件开发过程建立过程仿真模型。通过用例度量软件模块的复杂性来获取随机变量参数对模型调参,并采用该模型得到仿真结果。提出TDD模块选取算法来分析仿真结果并得出最佳TDD实施策略,最终为项目经理提供合理的决策。     

基于Petri网的采购业务流程建模及仿真优化

以国内某大型制造企业的采购业务流程为研究对象,用Petri网技术构建了现有环境下和优化后的采购流程模型,分别对这两种情况下的业务流程模型进行了时间定量分析,并利用ExSpect仿真软件模拟分析了原有采购流程及优化后流程的优劣。结果表明,通过应用信息技术和合理地选择供应商选择模式,提高了业务信息传递和处理的效率,缩短了采购周期。     

基于HTCPN的飞机维修保障过程建模与仿真

飞机维修保障过程模型是研究飞机维修保障系统结构与运行的基础,是典型的离散系统,层次赋时着色Petri网（HTCPN）有多种优点,是描述飞机维修保障过程的有力工具。论文介绍了HTCPN的建模方法,分析了飞机的维修保障过程,在CPNTools平台上,建立了基于HTCPN的飞机维修保障过程模型,并对模型进行了仿真,给出了分析结果,为研究飞机的维修保障提供了参考,为优化飞机维修过程、合理配置资源提供了依据。     

模拟移动床色谱分离体系模式与关键因子的计算机模拟研究

采用浮点编码遗传算法对模拟移动床色谱的分离系统模式进行了设计,并研究了,分离过程中传质和扩散对分离效果的影响。结果表明模拟移动床色谱中区2和区3的色谱柱的数目对提高生产强度起决定性的作用,而区1和区4的影响较小。同时改善分离过程中的传质与扩散可提高生产强度,在分离过程中传质所起的影响比扩散大得多。     

A continuous-system simulation language designed for LSI economics

As computing hardware gets cheaper, and labor gets more expensive, the economics of developing relatively limited distribution software such as continuous-system simulation languages for minicomputers (compared to Fortrans and other system software) changes. A philosophy of low-cost software is propounded here, and an example of a language adhering to that philosophy is presented. It is an equation-oriented language capable of solving differential or difference equations. It runs completely in memory (requires no mass storage device). Examples of its use are given, including a PHYSBE solution.     

基于Extend的舰船装备维修流程建模与仿真研究

通过分析一般舰船装备的维修流程,应用现有流程仿真软件Extend平台对舰船装备的维修流程进行建模和仿真。设置模型参数,根据模型运行结果分析模型设置的合理性,对维修的决策进行优化。     

基于资源共享的医疗服务流程的建模与仿真分析

针对目前患者到医院就诊等待时间长、医院内部资源利用效率低的问题,提出一种基于着色Petri网的医疗服务流程模型.利用仿真工具CPN Tools对整个医疗服务流程构建模型,在证明模型正确性的基础上对模型进行仿真分析与计算,获取患者就诊过程中各个环节的等待时间、被服务时间、医护人员的有效服务时间以及床位的有效服务时间等各项指标,最后通过对各项制约效率指标的分析,为资源进行合理调配,提高服务效率和资源利用率提供了理论依据.实验结果表明,该方法与以往就医模式相比,能够为流程重组及资源分配等各项优化措施提供事实数据,对同类研究具有一定借鉴意义.     

基于过程神经元的语音情感识别的建模与仿真

为克服由传统语音情感识别模型的缺陷导致的识别正确率不高的问题,将过程神经元网络引入到语音情感识别中来。通过提取基频、振幅、音质特征参数作为语音情感特征参数,利用小波分析去噪,主成分分析（PCA）消除冗余,用过程神经元网络对生气、高兴、悲伤和惊奇四种情感进行识别。实验结果表明,与传统的识别模型相比,使用过程神经元网络具有较好的识别效果。     

光控平面阵列建模与计算机仿真

光延时相控阵能够明显地改善普通相控阵雷达系统的带宽,然而大多数的研究和实验系统均基于光控线阵,故对光控面阵的分析和研究有着重大的现实意义.针对在平面阵列的行、列上中同时使用子阵延时、单元移相的光延时波控技术的二维扫描光控面阵,建立了光控平面阵列的数学模型,通过该数学模型完成了光控平面阵列方向图及其在不同的子阵划分和不同指向角下的计算机仿真,仿真结果表明光控平面阵的行、列子阵划分方式和指向角对阵列带宽均存在重大影响,这为进一步研究光控平面阵列奠定了重要基础.     

基于区块链原理的集装箱共享模式下集装箱运输流程建模与仿真

针对集装箱存量共享与增量共享均不能有效实施的问题，提出基于区块链原理的集装箱共享模式。首先，阐述基于区块链原理的集装箱共享模式的运作机制；其次，分析在该模式的作用下，集装箱运输流程发生的变化；然后以Petri网理论为基础，使用CPN Tools分别建立传统模式与基于区块链集装箱共享模式下的集装箱运输流程的赋时着色Petri网（CPTN）模型；最后，对模型进行仿真实验，选取不同模式下接收订单到提取空箱装货的时间、路运段空车行驶时间比例、订单损失率、作漏装的集装箱比例这四项指标对比分析。实验结果显示，与传统模式下相比，基于区块链的集装箱共享模式下，发货人提箱时间缩短，集卡空车行驶比例减小5.28%，不再出现因船期与订单时间窗不匹配而损失的订单，作漏装的集装箱比例减小6.99%。通过仿真实验结果可知，基于区块链原理的集装箱共享模式不仅能够弥补集装箱存量共享与增量共享中存在的不足，而且对集装箱运输流程起到优化作用，是集装箱运输行业实现降本增效的一种有效途径。     

装配序列约束下的飞机虚拟维修过程建模仿真

针对当前飞机虚拟维修过程模型固化,对维修复杂行为关系缺乏考虑,无法满足学员多样性实训需求的现状,充分考虑了飞机系统的复杂度、学员操作的不规范性和随机性等因素,依据各维修装配序列间的优先约束关系,构建了优先约束矩阵,进而定义了优先约束时间有色Petri网模型。在系统梳理维修实体及其维修操作行为的基础上,提出了虚拟维修实体操作元模型和元模型融合下的过程建模,阐述了基于优先约束时间有色Petri网的动态虚拟维修过程实现方法。最后,以A320飞机加油活门的某一个随机拆卸过程为例,进行建模仿真,验证了模型的有效性。     

Modeling and distributed simulation of a broadband-ISDN network

A distributed approach to communication network simulation using a network of workstations configured as a loosely coupled parallel processor to model and simulate the broadband integrated services digital network (B-ISDN) is proposed. In a loosely coupled parallel processor system, a number of concurrently executable processors communicate asynchronously using explicit messages over high-speed links. Since this architecture is similar to that of B-ISDN networks, it constitutes a realistic testbed for their modeling and simulation. The authors describe an implementation of this approach on 50 Sun workstations at Brown University. Performance results, based on representative B-ISDN networks and realistic traffic models, indicate that the distributed approach is efficient and accurate