NTNUJAVA Virtual Physics Laboratory
Enjoy the fun of physics with simulations!
Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

Easy Java Simulations (2001- ) => Information and Download => Topic started by: Fu-Kwun Hwang on March 02, 2004, 09:30:32 am



Title: Easy java simulation (Download and related informations)
Post by: Fu-Kwun Hwang on March 02, 2004, 09:30:32 am
Easy Java Simulations (Ejs) is a software tool designed for the creation of computer simulations. It is a media for making, doing , creating and best of all, it can be used as a modeling tool.  Construction, simulation, visualization, and analytic description of the physics model are linked during the creation process.  With Ejs, the task of creating a simulation is greatly simplified.  That is, the majority of the programming work is done by automatic code generation based upon text-based instructions, mathematic formula about the model and menu/mouse selections from the designer creating the graphical user interface for the simulation.  Java source code is generated automatically and compiled into class files. In addition, a jar file and the associated html pages are produced for users to view the simulation with a browser. This automatic code generation allows the Ejs user to concentrate on describing the model by defining the parameters related to the model, providing equations for the evolution of those parameters, setting the constraints between variables, and building a graphical representation. An additional advantage of using Ejs is that it causes the designer who is building the simulation to think through the problem in a new way. Ejs was developed for an Open Source Physics Project at the University of Murcia, Spain. Ejs, and the simulations created with it, can be used as independent programs under different operating systems, or be distributed via the internet and run within html pages by most popular web browsers.

Please check out Easy Java Simulations: An Interactive Science Learning Tool (http://imej.wfu.edu/articles/2003/2/01/)

The following is a flash movie shows you how to create simulation with EJS. (FInd out how easy it can be!)
http://www.phy.ntnu.edu.tw/ntnujava/swf/kepler_e.swf
  1. Original author's web site Francisco Esquembre  (http://fem.um.es/Ejs/index.html). He is also a member of Conceptual Learning of Science CoLoS group (http://colos.org/)
  2. download Latest version of Ejs   (http://www.phy.ntnu.edu.tw/demolab/download/ejs.zip)
    Installation Procedure: Need Jav Run time version 1.5 or later!
    1. Unzip downloded file to any directory in your computer (for example:c:\) It will create a new subdirectory: Ejs
    2. Double Click Ejs/EjsConsole.jar to run it!
  3. Online paper  Easy Java Simulations: An Interactive Science Learning Tool (http://imej.wfu.edu/articles/2003/2/01/index.asp)
  4. online demo
  5. Ejs manual  (http://www.phy.ntnu.edu.tw/demolab/download/EjsManual3.1.pdf)
  6. tutorial: movie files created with camtesia (Mbyte)
    • a. created applet embeded in html page (http://www.phy.ntnu.edu.tw/demolab/osejs/avi/ejs1.exe)
    • b.  create document for the generated applet (http://www.phy.ntnu.edu.tw/demolab/osejs/avi/ejs2.exe)
    • c. define variable for the simulation (http://www.phy.ntnu.edu.tw/demolab/osejs/avi/ejs3.exe)
    • d. provide differential equation for the simulation (http://www.phy.ntnu.edu.tw/demolab/osejs/avi/ejs4.exe)
    • e. create Graphic User Interface (GUI) and link parameters to the variables in our model (http://www.phy.ntnu.edu.tw/demolab/osejs/avi/ejs5.exe)  

      Then you can click the run button to create the applet/html page and run the simulation.


Title: Download and installation
Post by: Fu-Kwun Hwang on August 08, 2006, 02:32:15 am
Installation procedure:
You computer need to have Java Run time (http://www.java.com/en/download/manual.jsp) installed.
Unzip the downloded file  (http://www.phy.ntnu.edu.tw/demolab/download/EjsLatest.zip)to any directory (for example: c:) It will create a subdirectory Ejs

Double click Ejs/EjsConsole.jar to run it!
And it is all free! ::)


Title: Re: Easy java simulation (Download and related informations)
Post by: dickda on March 18, 2007, 01:11:00 pm
Thanks for a very valuable tool.  I was a programmer in a former career and can appreciate the effort that was involved.  My class will greatly benefit from this.

Richard Damian
Advanced Placement Physics with Calculus
George Washington High School
San Francisco


Title: Re: Easy java simulation (Download and related informations)http://fem.um.es/Ej
Post by: Fu-Kwun Hwang on May 18, 2007, 09:55:02 pm
The following links are not available.
1. Easy Java Simulations 3.46 beta (http://fem.um.es/Download/Ejs/Ejs3.46_070428.zip) (updated April 28th, 2007, aprox. 9Mb. ZIP Windows file) :  This is the LATEST beta (i.e. non-official but HIGHLY RECOMMENDED) version. Backwards compatible, the documentation is NOT up-to-date.

2.Easy Java Simulations 3.4  (http://fem.um.es/Download/Ejs/Ejs3.4_051101.zip)(updated November 2005, aprox. 6.3 Mb. ZIP Windows file) This is the LATEST and GREATEST version. It is backwards compatible.

3.  Manual for Ejs 3.4  (http://fem.um.es/Download/Ejs/EjsManual_en_3.4_050914.pdf)(updated September 2005,, aprox. 1.4 Mb., PDF format): This is the introductory, step by step, full of examples, manual. Appendices (see below) are also useful.

4. HTML reference pages (http://fem.um.es/Download/Ejs/Reference.zip)  for all view elements in a single compressed file.

5.  Combined use of Ejs and Matlab (http://fem.um.es/Download/Ejs/EjsAndMatlab.pdf)  (updated September 2004,  aprox. 600 Kb., PDF format) Intructions to use Ejs and Matlab/Simulink together.
 


Title: Re: Easy java simulation (Download and related informations)
Post by: briggs451 on December 09, 2007, 12:18:28 am
Hello,
I see that this site hasn't been updated for quite a long time.  Is anyone still there?

I'm interested in a particular simulation to visualize aerodynamic flow over a two-dimensional model.  Specifically, the drag created or reduced by varying the parameters of the model.

The application is to determine where drag is being created by a truck towing a trailer at typical highway speeds, and how the drag may be reduced by introducing air deflectors of various shapes and positions.

I have a recreational vehicle (trailer) that I tow with my pick-up truck.  I notice that there is a significant difference in fuel consumption, engine effort, and attainable speed depending on the direction of the wind relative to my direction of travel.  I would like to simulate introducing various size and shape wind deflectors and to be able to visualize the effects graphically.  I can produce a to-scale, two-dimensional model of the assembly in .mpeg format.

I have degrees in physics and mathematics, but it has been a very long time since I've used this knowledge so please don't assume any expertise. Btw, if anyone already has the simulation software and  is interested in collaborating with me on this, e-mail me at briggs451@yahgoo.com

Gary Briggs
Fort Worth Texas, USA


Title: Re: Easy java simulation (Download and related informations)
Post by: briggs451 on December 09, 2007, 12:38:10 am
There's a typo in my e-mail address.  Should be briggs@yahoo.com.


Title: Re: Easy java simulation (Download and related informations)
Post by: briggs451 on December 09, 2007, 12:39:48 am
Still wrong.  -*- :-[


Title: Re: Easy java simulation (Download and related informations)
Post by: Fu-Kwun Hwang on December 09, 2007, 10:03:41 am
The drag force could be model with F=-k1*V*A or F=F=-k2*V2*A
Where k1,k2 are constant, A is the effective area (cross section) of the car,
and V is the relative velocity between car and wind.  V=Vcar - Vwind (component in the direction of the car)
For example: if the car is moving with speed v1 to the east, and wind is v2 from east to west.
Then V=v1-(-v2)=v1+v2;
If there is a an angle c (between wind and car) V=v1+v2*cos(c);
The power loss due to the wind can be calculated as  F*V
If you can find out how much power generated from the car was used to moving the car forward (much of the energy was wasted as thermal energy produced). You need to subtract the above power loss.
 
Another way to model it is from the experimental data. If you can record data for different conditions systematically,
model can be created from those data and we can create simulation to compare with the data.



Title: Re: Easy java simulation (Download and related informations)
Post by: phykon on August 19, 2008, 06:45:21 pm
hi for all one here
i really like this program its solved my problem ,but i have one problem i need this solution
how can i publish my project to internet pages
before one day i finished my project but when i publish to internet as applet the project was not worked correctly . so please i would like to see the best mechanism for this solution

best regards

 ;)


Title: Re: Easy java simulation (Download and related informations)
Post by: lookang on December 28, 2008, 09:21:55 pm
Installation Procedure: Need Jav Run time version 1.5 or later!

the video i made which explains How to install Java Runtime Environment [JRE] for running Easy Java Simulation


also found here http://www.um.es/fem/EjsWiki/index.php/Main/Webcasts


Title: Re: Easy java simulation (Download and related informations)
Post by: Fu-Kwun Hwang on December 28, 2008, 09:54:49 pm
Download JRE from sun's web site and install it should be fine.
Normally, you do not need to set the file options (the part to set java program to open jar file).
It will be done by the installation process.


Title: Re: Easy java simulation (Download and related informations)
Post by: lookang on December 29, 2008, 07:38:33 am
the problem(s) i faced on a new OS installation.

1. jar was already used by another program some ZIP program, Java Runtime Environment [JRE] was installed but failed to launch, even  after reinstalling Java Runtime Environment [JRE].

2. removing existing Java Runtime Environment [JRE] and reinstall also give problem, the installer cannot find the installation file ( i can't remember the name of the file &#^$%.msi i think), n\i need to direct the installer to my pc folder in document and setting....... for installation to continue.

3. even after fixing the installation, jar is associated to another java program i assigned during trouble shooting.

4. finally fixed the problem only after i click on the restore button for the file association then my EJS can run on my new OS.

strange but it happened to me! ;D

On the other hand,
i also agree with you that normally Java Runtime Environment [JRE] is very easy to install


Title: Re: Easy java simulation (Download and related informations)
Post by: Fu-Kwun Hwang on December 29, 2008, 08:35:46 am
Because jar file is the same format as zip file.
You can change extension jar to zip, and use uncompression program (winrar or unzip ...) to open it.
So it might be the ZIP/UNZIP program that change the default program for jar.
For exmaple: WinRar ....etc.


Title: Re: Easy java simulation (Download and related informations)
Post by: kambinan on July 12, 2010, 05:40:37 am
Thanks friends :):)
[hide]
http://ww.sahtekar.net (http://ww.sahtekar.net)]/hide]


Title: Re: Easy java simulation (Download and related informations)
Post by: garymauricio on February 14, 2015, 11:38:28 am
Thank you guys.


Title: Re: Easy java simulation (Download and related informations)
Post by: florentiinas on November 24, 2015, 11:33:56 am
can i create a car simulation with fuzzy system?


Title: Re: Easy java simulation (Download and related informations)
Post by: jhkmal on February 18, 2016, 08:43:13 pm
It was very interesting
thanks all


Title: Re: Easy java simulation (Download and related informations)
Post by: kmspicosoftbd93 on January 02, 2017, 01:53:44 pm
It was very interesting
thanks all


Title: Re: Easy java simulation (Download and related informations)
Post by: smily on January 04, 2017, 07:13:01 pm
Very useful Thanks