vensim

vensim

中文介绍:

Vensim是由美国Ventana Systems, Inc.所开发，为一可观念化、文件化、模拟、分析、与最佳化动态系统模型之图形接口软件。Vensim可提供一种简易而具有弹性的方式，以建立包括因果循环(casual loop)、存货(stock)与流程图等相关模型。

使用Vensim建立动态模型，我们只要用图形化的各式箭头记号连接各式变量记号，并将各变量之间的关系以适当方式写入模型，各变量之间的因果关系便随之记录完成。而各变量、参数间之数量关系以方程式功能写入模型。透过建立模型的过程，我们可以了解变量间的因果关系与回路，并可透过程序中的特殊功能了解各变量的输入与输出间的关系，便于使用者了解模型架构，也便于模型建立者修改模型的内容。

英文介绍:

Version 5.7 is now available. This adds Unchangeable Constants, considerable performance improvements during optimization and a new VECTOR SELECT function that simplifies subscript relationship management.

Version 5.6b is now available. This version adds in the capability to apply the Graph, Strip Graph, Table, Sensitivity Graph, Stats and Document tool to multiple variable selections making it easier to look at a collection of variables together.

Version 5.6a is now available. This version supports Unicode and increases the functionality of the Vensim Model Reader to be able to open Venapps and Vensim DLL based applications. PLE Plus also supports hiding in this release.

Version 5.5d of Vensim is now available making it simpler to share your models with others and to control the way others can access your work. The new package publication feature allows you to send everything needed to run a model in a single file making sure the people you send it to see what you see. It also allows you to mark models so that they can’t be changed by the people receiving them. In addition there are a number of smaller changes, new functions and problem corrections. See the readme notes for more details.

Version 5.4 - Vensim PLE now supports input output objects and allows you to override behavior in SyntheSim. These changes are aimed at making PLE more effective an all teaching environments.

Vensim 5.3a is now available for downloading. A number of small improvements have been made to 5.3 which included new navigation capabilities, more hide levels with layered simulation, better pasting and improved performance with nonstandard character sets.

We have also increased the functionality of Vensim PLE to support the creation of models with multiple views and make use of data.

VensimPLE即Vensim系统动力学模拟环境个人学习版，是Vensim软件的一种，是为了更便于学习系统动力学而设计的。VensimPLE主要有以下几个特点:

①利用图示化编程建立模型。Vensim的用户界面是标准的Windows应用程序界面，除支持菜单和快捷键外，还提供多个工具条或图标，这使用户使用非常方便。在Vensim中，“编辑”实际上并不存在，只有建模的概念。只要在启动VensimPLE系统后得到的主窗口中，依据操作按钮(画图工具)画出简化流率基本流图，再通过Equation Editor输入方程和参数，就可以直接进行模拟了。在Vensim 中，方程及变量不带时标，模型建立是围绕着变量间的因果关系展开。

②对模型提供多种分析方法。VENSIM所提供的分析工具可以分为两类:一类是结构分析工具，如cause tree功能可以将所有工作变量之间的因果关系用树状的图形形式表示出来;loops功能可以将模型中所有反馈环以列表的形式表示出来。另一类是数据集分析工具，如graph功能可以将各变量在整个模拟周期内的数值以图形的形式直观的给出，causes strip graph功能则将有直接因果关系的工作变量在模拟周期内的数值变化并列出来，一以追踪系统变量间的影响关系。Vensim V5.4a 系统动力学_系统思考软件