AIDA Interchange Format (AIF)

This repository contains resources to support the AIDA Interchange Format (AIF). It consists of:

• a formal representation of the format in terms of an OWL ontology in java/src/main/resources/com/ncc/aif/ontologies/InterchangeOntology. This ontology can be validated using the SHACL constraints file in java/src/main/resources/com/ncc/aif/aida_ontology.shacl.

• utilities to make it easier to work with this format. Java utilities are in java/src/main/java/com/ncc/aif/AIFUtils.java, which can be used by adding a Maven dependency on com.ncc:aida-interchange:1.1.0. A Python translation of these utilities is in python/aida_interchange/aifutils.py.

• examples of how to use AIF. These are given in Java in the unit tests under java/src/test/java/com/ncc/aif/ExamplesAndValidationTests. A Python translation of these examples is in python/tests/Examples.py. If you run either set of examples, the corresponding Turtle output will be dumped.

• the validateAIF command line utility that can be used to validate AIF .ttl files. See below for details.

We recommend using Turtle format for AIF when working with single document files (for readability) but N-Triples for working with large KBs (for speed).

Installation

For instructions on installing the Java code, see the AIF Java README

For instructions on installing the Python code, see the AIF Python README

The AIF Validator

The AIF validator is an extension of the validator written by Ryan Gabbard (USC ISI) and converted to Java by Next Century. This version of the validator accepts multiple ontology files, can validate against NIST requirements (restricted AIF), and can validate N files or all files in a specified directory.

Running the Java AIF validator

In order to run the Java AIF validator, you must first install the AIF Java validator code. Instructions to install the Java AIF Validator code can be found in the AIF Java README.

To run the validator from the command line, run target/appassembler/bin/validateAIF with a series of command-line arguments (in any order) honoring the following usage:
Usage:
validateAIF [-hov] [--ldc] [--nist] [--nist-ta3] [--pm] [--program] [--abort[=num]] [--depth[=num]] [-d=DIRNAME] [-t=num] [--ont=FILE...]... [-f=FILE...]...

Either a file (-f) or a directory (-d) must be specified (but not both).
Exactly one of --ldc, --program, or --ont must be specified.
Ontology files can be found in src/main/resources/com/ncc/aif/ontologies:

• LDC (LO): LDCOntology
• Program (AO): EntityOntology, EventOntology, RelationOntology

Validator return values

Return values from the command-line validator are as follows:

• 0 (Success). There were no validation (or any other) errors.
• 1 (Validation Error). All specified files were validated but at least one failed validation. Supersedes a File Error.
• 2 (Usage Error). There was a problem interpreting command-line arguments. No validation was performed.
• 3 (File Error). A file was rejected or couldn't be validated, either due to an I/O error, a validation engine error, or because it didn't meet certain criteria. Logging indicates the nature of the problem(s). Validation may have been performed on a subset of specified KBs. If there is an error loading any ontologies or SHACL files, then no validation is performed.

Running the validator in code

To run the validator programmatically in Java code, first use one of the public ValidateAIF.createXXX() methods to create a validator object, then call one of the public validateKB() methods. createForLDCOntology() and createForProgramOntology() are convenience wrappers for create(), which is flexible enough to take a Set of ontologies. All creation methods accept a flag for validating against restricted AIF; see the JavaDocs. Note that the original ValidateAIF.createForDomainOntologySource() method remains for backward compatibility.

Once the validator has been initialized, there are several APIs to validate KBs and retrieve results. validateKB() simply returns whether or not the KB is valid. If you want any information about why the KB was invalid, use one of the validateKBAndReturnXXX() methods. Results can be returned as multiple error reports, or as one combined report, but note that for some validations, particularly large files with many violations, combining reports could incur significant overhead.

Failing fast

The AIF Validator can be told to "fail fast," that is, exit as soon as a few SHACL violations are found in the specified KB. On the command-line, use the --abort option to have the validator exit after three violations. Specify a number after the --abort flag to exit after that number of violations. The validation summary will display the number of aborted validations-- but if your file has the exact number of violations as the threshold, it will still be counted as an aborted validation.

NOTE: As of this writing, if you set the threshold too low (less than 3), the validator might erroneously return that your KB is valid. This appears to be a current bug or limitation in the TopBraid shacl library. Consequently, the command-line validator will reject thresholds less than 3.

Without the --abort option, the entire KB will be validated with full output of all violations.

To fail fast when using the validator programmatically in Java code, use ValidateAIF.setAbortThreshold() to set an error threshold.

Shallow validation

The --depth option performs a "shallow" validation in which each SHACL rule (shape) only considers a subset of its target nodes. The size of this subset (i.e., the depth of the validation) can be specified on the command line. For example, --depth=100 means that if your file has 30,000 event arguments, then the aida:EventArgumentShape will only be applied to 100 event arguments, significantly speeding up generation of an error report. Any violations in these 100 nodes will be included in the error report. By default (if no depth is specified), only 50 target nodes will be tested. The --depth option requires enabling the multi-threaded validator via the -t option. Unlike failing fast, shallow validation ends early whether or not it finds any SHACL violations.

To enable shallow validation programmatically in Java code, use ValidateAIF.setDepth() and specify a depth.

Memory considerations

Validation of a large files can require significant system resources, particularly system RAM. By default, the Java heap will use up to half of the available RAM on your system. If you want to set a higher (or lower) maximum, then set the JAVA_OPTS environment variable to, for example, -Xmx16G to use up to 16GB of RAM.

Alternatively, you can add <extraJvmArguments>-Xmx16G</extraJvmArguments> to your pom.xml file in the <configuration> block of the appassembler-maven-plugin plugin.

FAQ

Please see FAQ.md for frequently asked questions.

Contact

AIF was designed by Ryan Gabbard (gabbard@isi.edu) and Pedro Szekely (pszekeley@isi.edu) of USC ISI. Gabbard also wrote the initial implementations of the associated tools. The tools are now supported and extended by Next Century. For questions related to AIF, please contact AIF Support (aif-support@nextcentury.com).

The open repository will support an open NIST evaluation. For questions related to this evaluation, please contact Hoa Dang (hoa.dang@nist.gov).

Legal Stuff

This material is based on research sponsored by DARPA under agreement number FA8750-18- 2-0014 and FA875018C0010-HR0011730814. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon.

The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of DARPA or the U.S. Government.

The AIF repository has been approved by DARPA for public release under Distribution Statement "A" (Approved for Public Release, Distribution Unlimited).