Generator for Time-evolving Regional Data
Last update: June 12, 2002

Table of Contents

  1. Overview
  2. Documentation
    a)   G-TERD
    b)   Visualization tool
    c)   Example data sets
  3. What to Read
  4. Files to Download
  5. FAQs
  6. Bugs
  7. Copyright and Distribution


1. Overview
G-TERD is a novel approach for data generation, which is specifically designed for applications stemming from the field of time-evolving regional data. The basic concepts that determine the function of G-TERD are the structure of complex two-dimensional regional objects, their color, maximum speed, zoom and rotation-angle per time slot, the influence of other moving or static objects on the speed and on the moving direction of an object, the position and movement of the scene-observer, the statistical distribution of each changing factor and finally, time.

G-TERD is a software tool highly parameterized so that different parameter values may produce spatio-temporal data set distributions with different characteristics. Experimenters may control the behavior of the generator by defining parameters and statistical models. Such an approach considers the characteristics of a wider range of applications.

Experimenters may specify the time domain and the length of the size of the workspace, the maximum number of objects in the sample, their minimum and maximum speed, zoom and rotation-angle per time slot, the percentage of static and moving objects, and finally, the length of the field of vision of the scene-observer and the number of colors it supports.

Experimenters may also decide about the statistical model that should follow the number of new objects and sub-objects per time slot, the deletion time slot of an object or sub-object, its speed, zoom and rotation-angle per time slot, and finally the period of time that must elapse before the next computation of an attribute such as the color, speed, zoom of an object or sub-object, etc. Various statistical distributions are supported for that purpose.

G-TERD allows experimenters to compose many different individual sub-scenarios and it can conjuncts them by merging the resulting data sets.

The Web site of G-TERD provides access to the generator and its source code. Therefore, future researchers have the ability to adjust the algorithm of the generator according to different classes of spatio-temporal database application requirements and to produce sample data sets for their own needs.


2. Documentation

The source code of G-TERD was written in C language under the platform of Microsoft Developer Studio 97 (Visual C++ 5.0). Experimenters may download the source code of G-TERD with succinct description of every routine in it.
Experimenters may use the executable file 'g_terd.exe' of G-TERD in order to produce their own synthetic time-evolving regional data sets. Experimenters may set the user-defined parameters and statistical models through the file: 'inputs.txt'. After running the executable file of G-TERD, some new files will be created in the working directory:
- the files "Im*.col" which are the resulting multicolored images (the time-evolving data set),
- the file "log.txt" which reports the messages that appear on the screen,
- the file "errors.txt" where experimenters may find some help, in cases where G-TERD can not be executed because of a wrong setting of the user-defined parameters,
- a new directory called "visual" which contains files that will be used by the visualization tool,
- other not important files.

b) Visualization Tool
The visualization tool is based on Gnuplot 3.7 for Microsoft Windows. Experimenters may use this tool to visualize their own resulting regional data sets by calling the file: 'visual.exe'.
Precondition: the visualization tool has to be decompressed and run in the directory where the executable file of the G-TERD is. Otherwise: an error message is printed.
On the moment the visualization tool supports only ten colors to visualize.

c) Example data sets
Five sample time-evolving regional data sets are offered. The corresponding scenarios and the values of the user-defined parameters and statistical models are described in Section 6 of the Technical Report of G-TERD. Experimenters may visualize these demo regional data sets by calling the file 'demo.exe'.
Precondition: the compressed file of the example datasets has to be decompressed and run in the directory where the executable file of G-TERD and the visualization tool is. Otherwise: an error message is printed.


3. What to Read
Before trying to understand G-TERD and its source code, please read carefully the following paper:

T. Tzouramanis, M.Vassilakopoulos and Y. Manolopoulos: “ On the Generation of Time-evolving Regional Data”, Technical Report, Data Eng. Laboratory, Dep. of Informatics, Aristotle University, Greece, 2001 (GeoInformatica, in print).

or contact with T. Tzouramanis, M. Vassilakopoulos or Y. Manolopoulos.


4. Files to Download

Executable file of G-TERD (last update: March 7, 2001)
Source code of G-TERD (last update: March 7, 2001)
Visualization tool (last update: March 7, 2001)
Sample data sets (last update: March 7, 2001)
Samples of color images created by G-TERD (last update: June 12, 2002)
Directions for use: please read carefully the .TXT files that can be found in each of the above compressed files.


5. FAQs
No any reported questions on the moment.


6. Bugs
Send bug reports to Theodoros Tzouramanis. When reporting bugs, please include the exact wording of any error messages and the file 'inputs.txt'. Mr. Tzouramanis will contact with you as soon as possible.


7. Copyright and Distribution
Permission is granted to copy G-TERD, to re-distribute it on a nonprofit basis, and to use it for any purpose, subject to the following restrictions and understandings:

  1. Any copy made of this software must include the authors’ names and this copyright notice in full.
  2. All materials developed as a consequence of the use of this software shall duly acknowledge such use, in accordance with the usual standards of acknowledging credit in academic research.
  3. The authors have made no warranty or representation that the operation of this software will be error-free or suitable for any application, and they are under no obligation to provide any services, by way of maintenance, update, or otherwise. The software is an experimental prototype offered on an as-is basis.
  4. Redistribution for profit requires the express, written permission of the authors.



Data Engineering Laboratory, Dept. of Informatics, Aristotle Univ. of Thessaloniki, Greece © 2001 DELAB AUTH. All rights reserved.
Last update: 12/06/2002

Webmaster: Theodoros Tzouramanis