天然气液化流程模拟与优化分析

天然气的液化流程模拟在一定形式上推动了我国天然气（LNG）工业的发展,目前需要运用具有专业的天然气流程模拟软件来对天然气的流程进行科学化的模拟和设计,进而推动LNG工业的持续发展和进步,为实现国际化的发展目标而进行相关流程的优化。     

基于MOLCA的催化裂化分离系统多目标模糊优化

催化裂化分离系统由分馏系统和吸收稳定系统两部分组成,本文将催化裂化分离系统作为一个整体进行研究。应用流程模拟软件Aspen Plus建立了该系统的全流程模拟,在此基础上,以干气中C_（3＋）组分数最小和系统能耗最少作为优化目标,建立了该系统的多目标优化数学模型。应用模糊优化理论对优化约束条件进行模糊处理,并采用多目标列队竞争算法（MOLCA）对模糊优化模型以及普通优化模型进行求解。计算结果表明,采用模糊优化的结果优于普通优化的结果,干气品质和系统能耗都得到了明显的改善。为催化裂化分离系统的操作优化提供了参考。     

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。     

对二甲苯工艺全流程实时动态仿真系统

介绍了年产５．５万吨对二甲苯（ＰＸ）工艺的全流程产时动态仿真培训系统，该系统采用微机网络结构模拟了化工过程特性和仿ＰＲＯＶＯＸ集散控制系统（ＤＣＳ），并拥有工艺现场模拟站以及智能导师指令台，本文从ＰＸ流程、软硬件结构、建模过程等方面介绍了该系统的设计。     

排队模拟的误差分析与修正

排队模拟的误差分析与修正，一直是国际仿真模拟界研究的重要课题［１］。虽然已经有了一些排队模拟的统计学处理方法及准则［４］，但模拟结果的误差问题至今仍未很好解决。为了使仿真模拟结果对系统分析提供有价值的数据，必须对模拟结果进行修正。本文提出了三种误差修正方法：（１）松驰法修正；（２）Ｍ／Ｍ／１型排队模拟误差曲线修正；（３）置信区间修正。它们的修正是基于对Ｍ／Ｍ／１型排队模拟结果的分析。     

玉米发酵制备ABE部分流程的模拟与优化

利用Aspen Plus模拟软件对生产丙酮-丁醇-乙醇的玉米发酵过程的前期处理和后续精馏过程进行模拟,获得了各精馏塔的最佳操作条件。以减少流程耗能和耗水量为目标,对分离流程进行了模拟优化;研究了废热利用和引入蒸汽喷射泵等热集成方法对减少整个流程消耗蒸气和耗水量的效果;其中蒸汽喷射泵节省蒸汽的效果最明显,通过热集成方法的优化可节省全流程约30%的蒸汽用量以及大量的1次水和循环水消耗量。     

富含CO2

在全流程模拟的基础上对整个系统进行优化计算，考虑到描述各工段过程的数学上的复杂性，首先对各个单元做了简化处理，用简化的代数方程代替复杂的微分方程，从而使得优化过程大为简化。优化计算所提取的决策变量分别为进吸收塔压力     

工作流流程模型结构优化算法的研究

该文从一个新颖的角度提出一种优化工作流流程模型结构的算法,用进程代数CCS来描述工作流流程模型的定义,并引用了进程代数中的互模拟的思想,提出了互模拟活动集合以及子流程的定义,同时给出如何找出复杂工作流流程模型中的互模拟活动的算法,该算法的提出简化了工作流流程模型的结构,从而提高了流程的运行效率。     

芳烃系列装置生产方案的整体优化模拟

利用化工模拟软件,打破装置界区限制,从混合芳烃原料出发。以最终芳烃产品为目标,对现有的重整车间芳烃分离装置、特种溶剂油车间的重芳烃分离装置,以及苯酐车间的邻二甲苯分离装置进行多方案全流程模拟、并调整设备及流程顺序,进行整体优化,推出节能流程,在投资很小的情况下,降低能耗40％以上,取得了可观的经济效益。     

混合信号集成电路技术

首先介绍了混合信号集成电路的分类方法和应用概况；接着评述了混合信号电路的设计准则和低电压低功耗混合信号电路技术及当前混合信号电路设计的EAD工具；最后评述了模拟电路和混合信号电路的各种工艺技术，包括CMOS、双极、BiCMOS、SiGeHBT和GaAsIC等技术。     

Enhancing integrated earthquake simulation with high performance computing

Integrated earthquake simulation (IES) is a seamless simulation of the three earthquake processes, namely, the earthquake hazard process, the earthquake disaster process and the anti-disaster action process. High performance computing (HPC) is essential if IES, or particularly, the simulation of the earthquake disaster process is applied to an urban area in which 10^4∼6 structures are located. IES is enhanced with parallel computation, and its performance is examined, so that virtual earthquake disaster simulation will be made for a model of an actual city by inputting observed strong ground motion. It is shown that parallel IES has fairly good scalability even when advanced non-linear seismic structure analysis is used.     

Simulation Preorder over Simple Process Algebras

We consider the problem of simulation preorder/equivalence between infinite-state processes and finite-state ones. First, we describe a general method how to utilize the decidability of bisimulation problems to solve (certain instances of) the corresponding simulation problems. For certain process classes, the method allows us to design effective reductions of simulation problems to their bisimulation counterparts and some new decidability results for simulation have already been obtained in this way. Then we establish the decidability border for the problem of simulation preorder/equivalence between infinite-state processes and finite-state ones w.r.t. the hierarchy of process rewrite systems. In particular, we show that simulation preorder (in both directions) and simulation equivalence are decidable in EXPTIME between pushdown processes and finite-state ones. On the other hand, simulation preorder is undecidable between PA and finite-state processes in both directions. These results also hold for those PA and finite-state processes which are deterministic and normed, and thus immediately extend to trace preorder. Regularity (finiteness) w.r.t. simulation and trace equivalence is also shown to be undecidable for PA. Finally, we prove that simulation preorder (in both directions) and simulation equivalence are intractable between all classes of infinite-state systems (in the hierarchy of process rewrite systems) and finite-state ones. This result is obtained by showing that the problem whether a BPA (or BPP) process simulates a finite-state one is PSPACE-hard and the other direction is co -hard; consequently, simulation equivalence between BPA (or BPP) and finite-state processes is also co -hard.     

基于仿真的C4ISR系统设计方法及其支持环境研究

C4ISR系统的分析与设计是一项非常复杂的系统工程,而建模和仿真技术(M&S)作为系统分析与设计的一种关键技术有着广泛地应用.该文在对C4ISR系统的分析与设计过程进行研究的基础上,结合基于仿真的设计(SBD)方法,提出了基于仿真的C4ISR系统设计方法,深入探讨了在C4ISR系统分析设计全生命周期中运用SBD方法进行辅助设计的过程,并对其支持环境的设计进行了研究.     

Discovering simulation models

Process mining is a tool to extract non-trivial and useful information from process execution logs. These so-called event logs (also called audit trails, or transaction logs) are the starting point for various discovery and analysis techniques that help to gain insight into certain characteristics of the process. In this paper we use a combination of process mining techniques to discover multiple perspectives (namely, the control-flow, data, performance, and resource perspective) of the process from historic data, and we integrate them into a comprehensive simulation model. This simulation model is represented as a colored Petri net (CPN) and can be used to analyze the process, e.g., evaluate the performance of different alternative designs. The discovery of simulation models is explained using a running example. Moreover, the approach has been applied in two case studies; the workflows in two different municipalities in the Netherlands have been analyzed using a combination of process mining and simulation. Furthermore, the quality of the CPN models generated for the running example and the two case studies has been evaluated by comparing the original logs with the logs of the generated models.     

Using simulation to aid decision making in managing the usability evaluation process

ContextThis paper is developed in the context of Usability Engineering. More specifically, it focuses on the use of modelling and simulation to help decision-making in the scope of usability evaluation.ObjectiveThe main goal of this paper is to present UESim: a System Dynamics simulation model to help decision-making in the make-up of the usability evaluation team during the process of usability evaluation.MethodTo develop this research we followed four main research phases: (a) study identification, (b) study development, (c) running and observation and finally, (d) reflexion. In relation with these phases the paper describes the literature revision, the model building and validation, the model simulation and its results and finally the reflexion on it.ResultsWe developed and validated a model to simulate the usability evaluation process. Through three different simulations we analysed the effects of different compositions of the evaluation team on the outcome of the evaluation. The simulation results show the utility of the model in the decision making of the usability evaluation process by changing the number and expertise of evaluators employed.ConclusionOne of the main advantages of using such a simulation model is that it allows developers to observe the evolution of the key indicators of the evaluation process over time. UESim represents a customisable tool to help decision-making in the management of the usability evaluation process, since it makes it possible to analyse how the key process indicators are affected by the main management options of the Usability Evaluation Process.     

Discovering colored Petri nets from event logs

Process-aware information systems typically log events (e.g., in transaction logs or audit trails) related to the actual execution of business processes. Analysis of these execution logs may reveal important knowledge that can help organizations to improve the quality of their services. Starting from a process model, which can be discovered by conventional process mining algorithms, we analyze how data attributes influence the choices made in the process based on past process executions using decision mining, also referred to as decision point analysis. In this paper we describe how the resulting model (including the discovered data dependencies) can be represented as a Colored Petri Net (CPN), and how further perspectives, such as the performance and organizational perspective, can be incorporated. We also present a CPN Tools Export plug-in implemented within the ProM framework. Using this plug-in, simulation models in ProM obtained via a combination of various process mining techniques can be exported to CPN Tools. We believe that the combination of automatic discovery of process models using ProM and the simulation capabilities of CPN Tools offers an innovative way to improve business processes. The discovered process model describes reality better than most hand-crafted simulation models. Moreover, the simulation models are constructed in such a way that it is easy to explore various redesigns. A. Rozinat’s research was supported by the IOP program of the Dutch Ministry of Economic Affairs. M. Song’s research was supported by the Technology Foundation STW.     

基于HLA的火车站行李监测系统仿真开发

HLA是分布交互仿真的高层体系结构,它为复杂系统建模与仿真提供了公共的技术支撑框架.针对火车站的行李监测系统,提出了基于HLA的仿真开发设计.研究了系统的体系结构和工作原理,在此基础上着重论述了联邦仿真平台的构成和基于联邦开发和执行过程模型(FEDEP)的开发过程,进行了对象类和交互类的开发,对系统中主要的成员对象进行了联邦对象模型(FOM)和仿真对象模型(SOM)设计,给出了基于运行支撑框架(RTI)的仿真程序.     

基于HLA的武器对抗仿真系统开发研究

高层体系结构HLA建立一个能用的仿真框架，以解决不同仿真器，模型之间的互操作及仿真组件的可重用性问题。该文首先介绍了基于HLA的武器对抗仿真的结构，然后介绍了基于HLA的仿真应用系统的开发过程，最后，以飞机突防作战仿真为例，从应用的角度分析了基于HLA的武器对抗仿真系统开发过程和方法，同时，介绍了在HLA联邦中数据记录器的三种实现方法。     

A systematic literature review on the industrial use of software process simulation

ContextSoftware process simulation modelling (SPSM) captures the dynamic behaviour and uncertainty in the software process. Existing literature has conflicting claims about its practical usefulness: SPSM is useful and has an industrial impact; SPSM is useful and has no industrial impact yet; SPSM is not useful and has little potential for industry.ObjectiveTo assess the conflicting standpoints on the usefulness of SPSM.MethodA systematic literature review was performed to identify, assess and aggregate empirical evidence on the usefulness of SPSM.ResultsIn the primary studies, to date, the persistent trend is that of proof-of-concept applications of software process simulation for various purposes (e.g. estimation, training, process improvement, etc.). They score poorly on the stated quality criteria. Also only a few studies report some initial evaluation of the simulation models for the intended purposes.ConclusionThere is a lack of conclusive evidence to substantiate the claimed usefulness of SPSM for any of the intended purposes. A few studies that report the cost of applying simulation do not support the claim that it is an inexpensive method. Furthermore, there is a paramount need for improvement in conducting and reporting simulation studies with an emphasis on evaluation against the intended purpose.     

基于HLA的水面舰艇反潜仿真系统研究

HLA(高层体系结构)是美国防部指定的新一代通用的仿真框架标准,目的是解决仿真领域内的互操作性和可重用性问题。本文首先介绍了HLA仿真框架的结构和基于HLA的仿真应用系统的开发过程,然后以水面舰艇反潜仿真系统为例,从应用角度分析了基于HLA的仿真应用系统的开发过程和方法。