The Fuzzy SIT Algorithm

The Scene Identification and Tagging (SIT) algorithm based on Fuzzy Description Logics.

The theoretical background of SIT can be found in

• L. Buoncompagni, F. Mastrogiovanni and A. Saffiotti, "Scene Learning, Recognition and Similarity Detection in a Fuzzy Ontology via Human Examples," in the 4th Italian Workshop on Artificial Intelligence and Robotics. A workshop of the XVI International Conference of the Italian Association for Artificial Intelligence Bari, Italy, November 14-15, 2017, CEUR-WS, Vol-2054.
• L. Buoncompagni and F. Mastrogiovanni, "Teaching a Robot how to Spatially Arrange Objects: Representation and Recognition Issues," 2019 28th IEEE International Conference on Robot and Human Interactive Communication (RO-MAN), 2019, pp. 1-8, doi: 10.1109/RO-MAN46459.2019.8956457.
• L. Buoncompagni and F. Mastrogiovanni, "Dialogue-Based Supervision and Explanation of Robot Spatial Beliefs: a Software Architecture Perspective," 2018 27th IEEE International Symposium on Robot and Human Interactive Communication (RO-MAN), 2018, pp. 977-984, doi: 10.1109/ROMAN.2018.8525828.
• L. Buoncompagni and F. Mastrogiovanni, "A Framework Inspired by Cognitive Memory to Learn Planning Domains From Demonstrations," in Proceedings of the 6th Italian Workshop on Artificial Intelligence and Robotics co-located with the XVIII International Conference of the Italian Association for Artificial Intelligence (AIxIA 2019) Rende, Italy, November 22, 2019, CEUR-WS, Vol-2594.

Installation

Install Java8 Dependence

If you did not already, in an Ubuntu machine, install Java JDK 8 with

sudo apt update
sudo apt install openjdk-8-jdk

Locate the Java virtual machine installed with

jrunscript -e 'java.lang.System.out.println(java.lang.System.getProperty("java.home"));' 

It might return /usr/lib/jvm/java-8-openjdk-amd64/jre, which will be used later.

Install FuzzyDL and Gurobi Dependence

FuzzySIT depends on FuzzyDL, which have been tested at the version of the 09 January 2019. The FuzzyDL library comes as a jar that should be placed in the /libs folder.

FuzzyDL depends on Gurobi which gives a free license for Academic and non-commercial purpose.

After having a Gurobi account and the related license, download the Gurobi Optimizer tools. We used the version 8.0.1, which can be downloaded in Ubuntu with

wget https://packages.gurobi.com/8.1/gurobi8.1.0_linux64.tar.gz

Then, uncompress it in the /opt folder with

sudo tar -xf gurobi8.1.0_linux64.tar.gz -C /opt/

Now add the following environmental variables in the .bashrc and configure JAVA_HOME as found previously

export GUROBI_HOME="/opt/gurobi810/linux64"
export PATH="${PATH}:${GUROBI_HOME}/bin"
export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${GUROBI_HOME}/lib"
export JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64/jre"

Close and reopen the terminal, then generate the license file with

grbgetkey <licence_id>

where <licence_id> is given by Gurobi when you activate your license. The latter command should generate a file gurobi.lic in your home.

Now you can test FuzzyDL reasoner by referring to the README file of the FuzzyDL package.

Install FuzzySIT and Run an Example

To test FuzzySIT, clone it and (eventually) checkout in a relevant branch

git clone https://github.com/TheEngineRoom-UniGe/fuzzy_sit.git

To compile it go in the fuzzy_sit folder just cloned and run

gradle wrapper --gradle-version 6.8

which might require to install Gradle with sudo apt install gradle. Then run

./gradlew build

Finally, run the SceneHierarchyTest example with

./gradlew runExample

If your machine does not have a graphical user interface, the example will fail at the end of the script

If the example gives an error like

Exception in thread "main" java.lang.NullPointerException
at it.emarolab.fuzzySIT.core.SITTBox.querySubConcept(SITTBox.java:382)

it might be the case that the guroby path is not correctly configured.

To run other examples or to generate a jar of FuzzySIT as a library for your development we suggest to open the fuzzy-sit project with an IDE (e.g., Intellij IDEA) configured based on your .bashrc (e.g., opened from terminal in Ubuntu).

FuzzySIT Ontology Setup

SIT requires a FuzzyDL ontology (i.e., a file .fuzzydl) that is formatted in a specific manner.

It requires a header as

(define-fuzzy-logic zadeh)

(define-primitive-concept Object *top*)
(define-primitive-concept Scene  *top*)

(disjoint Object        Scene)
(disjoint SpatialObject Scene)
(implies  Object SpatialObject)

Then you should define the type of elements in the scene, e.g., for Spere and Cone use

(implies Sphere Object)
(implies Cone   Object)

Later you should define the type of relations among elements, e.g., Right and Left

(range  isRightOf Object)
(domain isRightOf SpatialObject)

(range  isLeftOf  Object)
(domain isLeftOf  SpatialObject)

Note that this implementation of fuzzyDL is case-sensitive, and it parses variable names with the CamelCase standard (a known issue occurs when variables end with a number, e.g., Right1). Always add is to the definition of the relations, while Of is optional.

Finally, we should define the features used by SIT to learn. Those are all the combinations of the types of elements and relations above obtained through reification, e.g.,

(define-concept SphereRight  (and Sphere (some isRightOf  SpatialObject)))
(define-concept SphereLeft   (and Sphere (some isLeftOf   SpatialObject)))

(define-concept ConeRight    (and Cone   (some isRightOf  SpatialObject)))
(define-concept ConeLeft     (and Cone   (some isLeftOf   SpatialObject)))

In this case, the SphereRight class represents a feature in the scene where "a sphere as something on the right".

You can configure and add as many types of elements and relations you like but be aware that computation complexity scales exponentially.

FuzzySIT API Structure

The core of FuzzySIT is composed by three main classes

• FuzzySITBase which is a container for common constants and configuration, e.g., FLAG_LOG_SHOW.
• SITABox which allows encoding and recognising a scene. A new SITABox should be instantiated for each observed scene.
• SITTBox which contains the scene categories in the memory. Only an instance of SITTBox should be used for each application. SITTBox allows
  • learning new scenes by the means of SITABox,
  • access and visualize the hierarchy of scenes structured on the basis of the ontology,
  • save or lead ontologies.

Runnables: Tests, Extensions and Examples

The FuzzySIT package comes also with some utilities used for testing purposes. In particular, in the runnableSITutility contains the following runnable scripts.

Both the FuzzySIT core, and the utilities read and write on auxialry file stored in the resources folder.

1. FuzzydlTest

It is a script to test the FuzzyDL reasoner by loading an ontology and solving queries.

2. SITExample

Is an example to show the usage of the FuzzySIT API base on a toy scenario.

3. GUI

Is a graphical user interface to simulate 2D arranges of objects. It is based on the JavaFx library, and it is currently commented since deprecated.

4. SceneHierarchyTest

Show a simulation of object configured as shown in the paper, and it concerns the hierarchy of spatial scenes in memory. This example is based on fuzzy degree given as input.

5. SpatialSceneExample

Show a simulation of object configured as shown in the paper, and it concerns the hierarchy of spatial scenes in memory. This example is different from SceneHierarchyTest since it uses fuzzy kernels to compute degrees based on the 2D object positions.

5. MemoryTest

Is a simulation done to publish results about a cognitive like memory, involving consolidation and forgetting of scene categories learned during time.

6. MonteCarlo

Is a preliminary simulation based on a Montecarlo approach to reconstruct a scene given its learned category. This example is not in a stable version.

7. ComputationComplexity

Is a simulation to log the SIT computation complexity to be later evaluated.

You can run the computation complexity test with the command

gradle clean runComputationTest -Pconcepts='2,6' -Prelations='2,4' -Pscenes='2,2,2' -Pelements='2,3,4' -PtasksLimit='2'

where

• -Pconcepts sets the number of possible types of object in the ontology,
• -Prelations sets the number of possible relations among objects in the ontology,
• -Pscenes sets the number of learning and recognition phase to perform (i.e., number of memory items at the end of the evaluation`),
• -Pelements sets the number of objects in each scene to evaluate. From this the number of relations in a scene is derived having, between each object added consegutively, (i) two relations plus (2) another relation with a probability of 0.5.
• -PtasksLimit sets the maximum number of threads to be used concurrently for the simulation.

The test is performed for each combination of concepts, relations, scenes and elements. The results are store as csv files in the folder src/main/java/resources/ComputationComplexityTest/log. CSV data is all express in millisecond or integer (e.g., for indices) and arranged in columns ordered as CSV data is all express in millisecond or integer (i.e., indices) and arranged in columns as: A,B,C,...,Q where

• A) An ordered identified based on the creation timestamp,
• B) A string identifying the ontology complexity (i.e., C-D),
• C) The Number of concepts in the ontology,
• D) The Number of relations in the ontology,
• E) Number of elements in the scene,
• F) Number of roles in the scene,
• G) Number of items in the memory (it should be an array with all equals elements, which size identifies the number of trials, and each element the nodes in memory when to stop),
• H) The encoding time before having learned a new scene,
• I) The recognition time before having learned a new scene,
• J) The learning time,
• K) The structuring time,
• L) The encoding time after having learned a new scene,
• M) The recognition time after having learned a new scene,
• N) The total time,
• O) Thread memory usage in bytes (this is an approximation based on ThreadMXBean.getThreadAllocatedBytes, which might be unreadable),
• P) Number of categories pre-recognised,
• Q) Number of categories post-recognised.

Contacts

Author: Luca Buoncompagni,
Affiliation: University of Genoa,
Date: 2021
Email: [email protected] (please, prefer GitHub issue if appropriate)
Licence: The FuzzySIT packager are under the GNU General Public License v3.0, while the dependences (i.e., Java, FuzzyDL, Gurobi, and jgrapht) are subjected to their relative licences.