The Timeline Ontology

This work is licensed under a Creative Commons Attribution License. This copyright applies to the Timeline Ontology and accompanying documentation in RDF. This ontology uses W3C's RDF technology, an open Web standard that can be freely used by anyone.

Table of Contents

1. Introduction
2. Namespaces
3. The Timeline model
4. Overview of Terms
5. Ontology Terms
1. Classes
2. Properties
6. References

Introduction

This document describes the Timeline ontology developed in the Centre for Digital Music in Queen Mary, University of London. The first draft of the ontology was written in November, 2004. Further details about the Timeline ontology, related ontologies, and the technologies on which this ontology is founded, please see the reference section.

This ontology is centered around the notion of timeline, seen here as a way to identify a temporal backbone. A timeline may support a signal, a video, a score, a work, etc. A particular instance of a timeline is the physical one, on which the 29th of October, 2007 is defined.

This ontology, used with the Event ontology, can be used to annotate sections of a signal, a video, or any temporal object. For example, it can be used to express:

1. This shot holds between this frame and that frame, in this video
2. This performance happened at that particular date
3. In this song, the first chorus is before the second verse
4. A new structural segment starts at 2 minutes and 43 seconds, on this signal
5. This signal is a sampled version of this one
6. This part of the score corresponds to this section in an actual performance (in progress...)

Some tools to manipulate data from this ontology can be found in the motools project on Sourceforge.

This documentation page is a first draft. All feedback on either the ontology or this page is welcomed! The best place to do so are the Event ontology mailing list or the Music ontology mailing list, for music-related use cases. Or feel free to email the authors mentioned aboved.

The design and layout of this ontology document is based on the Music Ontology and FOAF Vocabulary specification documents.

Namespaces

Several namespaces will be assumed to have been defined for the remainder of this document. These are as follows :

The Timeline Model

This ontology defines the TimeLine concept, representing a coherent backbone for addressing temporal information. Each temporal object (signal, video, performance, work, etc.) can be associated to such a timeline. Then, a number of Interval and Instant can be defined on this timeline, using the tl:onTimeLine property.

A timeline is associated to one or several coordinate systems, allowing to address a particular point on them. Here, we use XML-Schema datatypes to define these systems. Therefore, an instant defined on a timeline may be linked to a literal in the corresponding XSD datatype. Such restrictions are captured within the ontology, using sub-properties (constrained to one particular datatype) of the tl:at property.

Two timelines may be linked together, using the TimeLineMap concept. For example, the UniformSamplingMap concept subsumes TimeLineMap, and captures the fact that a digital timeline is a sampled version of an analog timeline (and holds information about the sampling frequency). Another example is the ShiftMap, which captures a simple translation between timelines.

An instant on a signal timeline (Smells like teen spirit, as published on the Nevermind album), and an interval on the physical timeline can be depicted as follows:

The corresponding RDF/N3 code is the following:

@prefix event: <http://purl.org/NET/c4dm/event.owl#>.
@prefix tl: <http://purl.org/NET/c4dm/timeline.owl#>.

:instant 
	a tl:Instant;
	tl:timeline <http://zitgist.com/music/signal/6da76448-982a-4a01-b65b-9a710301c9c9>
	tl:at "PT3S"^^xsd:duration;
	.

:interval
	a tl:Interval;
	tl:timeline tl:universaltimeline;
	tl:start "2001-10-26T12:00:00Z"^^xsd:dateTime;
	tl:duration "P7DT";
	.

Overview of Terms

An alphabetical index of the ontology terms, divided into classes, properties and individuals. All the terms are hyperlinked to their detailed description for quick reference.

Ontology Terms

Classes

Properties

References

1. Semantic Web Information
1. W3C Semantic Web Activity
2. Primer: Getting into RDF & Semantic Web using N3
2. Related projects
1. Music Ontology
2. Chord Ontology
3. Event Ontology
4. Friend of a Friend
3. (Somehow) related publications
1. The Music Ontology, ISMIR2007
2. An ontology-based approach to information management for music analysis systems