Replace README.md

README.md

 # PN4ECSS
 
-Petri Net for Electric Car-Sharing System.
+Petri Net for Electric Car-Sharing System (ECSS).
 
-Implementation of the ECSS PN model described in this paper (Modelling and Performance Analysis of
-Electric Car-Sharing Systems Using Petri Nets) with PNlib3.0 (https://github.com/AMIT-HSBI/PNlib) in Modelica. 
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+## Background
+
+Implementation of the ECSS Petri Net model described in [this paper]([Modelling and Performance Analysis of Electric Car-Sharing Systems Using Petri Nets | E3S Web of Conferences (e3s-conferences.org)](https://www.e3s-conferences.org/articles/e3sconf/abs/2020/30/e3sconf_evf2020_03001/e3sconf_evf2020_03001.html)) (shown as below) in Modelica.
+
+![ECSS](C:\Users\wang\Documents\Modelica\PN4ECSS\PN4ECSS.JPG)
+
+
+
+## Environments
+
+[OpenModelica v1.22.3](https://openmodelica.org/download/download-windows/)
+
+[PNlib v3.0.0](https://github.com/AMIT-HSBI/PNlib)
+
+## Model Description
+
+The implementation implemented "The City" subnets, but only two of them (left part), for some simplicity.
+
+The "Commercial and Industrial Center" subnets has been also implemented (right part). 
+
+With this model my computer runs already very slow 😑
+
+There are two Modelica models
+
+* `CarSharing.mo` is the model of a subnet of "The City" part.
+* `CarSharingSystem.mo` is the model of the whole ECSS system.
+
+![](C:\Users\wang\Documents\Modelica\PN4ECSS\CarSharingSystem.png)
+
+This model generates some stochastic user (demands), you can simulate: 
+
+* how many cars are in use, 
+* how many cars are charging thus not available, 
+* how many cars finished charging and are ready for being rent,
+* how many users don't have a car available so they just leave,
+* etc.
+
+Here you will find a gif to visualize the simulation result.
+
+![](C:\Users\wang\Documents\Modelica\PN4ECSS\PN4ECSS.gif)
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