20100427 Earthster Core Ontology

Earthster Core Ontology
A core domain ontology for Life Cycle Assessment

Introductions
Earthster is a project, led by Greg Norris, to provide free open source solutions supporting Life Cycle Analysis – that is evaluating the environmental and social impacts of products.
Brian McBride is a consultant, ontologist, developer and general dogsbody who has worked on semantic web technologies since 2000. He was co-chair of the RDFCore WG in W3C and the initiating developer of the Jena Java library.
Epimorphics is a Semantic Web startup based in the UK specialising in Linked Open Data.
http://www.earthster.org/
http://www.epimorphics.com/

Menu
A little bit about LCA
Why semantic web?
A fragment of ECO
A sense of the rest
The ECO-system
A little bit on method
ERF – an application
Wrapup
Season to taste with questions and discussion anytime

Life Cycle Assessment
What is a product’s impact on the environment and society?
In production aka cradle to gate?
In use – total lifecyle?

Life Cycle Assessment
Impact assessment is currently a complex, artful process – this description is considerably simplified
Define the goals of the assessment
Analyse your supply chain
Create an inventory of emissions and aggregated along the supply chain
Assess the impact of those effects on issues of interest e.g. global warming, human health, ...
There are impact assessment methods that define weighted contributions and give a score e.g. Emissions of CO2equivalent for GHG or DALYs for human health.

Earthster Aim:Publish LCA Data on the Web
To inform folks about the sustainability implications of the decisions we make
At all points in the supply chain:
Simple measures for the consumer
Decision support for the industrial buyer
Detailed information for the product/process designer
Enable consumer pressure to flow back down the supply chain to improve the sustainability characteristics of products

Why Semantic Web?
Effects
Publish the data on the web makes it most freely available – and that is what the semantic web is for
Linking to other data sources – that is what Linked Open Data is for
Find an alternative pesticide that targets the same class of organism
Link to Good Relations data
Operations
Interoperability
Harmonize competing systems by defining a common conceptual model
Harmonize competing vocabularies by defining common reference data
LCA research is ongoing – the data required is changing over time
Finding the best available data

ECO: A Core Domain Ontology
Aim is to offer a vocabulary for core concepts in LCA
Not lists of instances
Instances are present if they are a logical necessity of the concept
Core ontology changes when core concepts change not when a new instance is invented
Trying to express the consensus conceptual model for the field
Reverse engineering existing file formats and database schemas

A Fragment of ECO - 1
Process
Model
Models
Distinguish between statements about a process and a model of the process
Allows multiple inconsistent descriptions of the process with a contradiction
Gives us somewhere to hang model metadata without named graphs or reification

A Fragment of ECO – 2
Process
Model
Quantified Effect
hasQuantifedEffect
Models
Quantity
Effect
Effect is a new abstraction not found in current LCA data structures
Key feature is that it is aggregatable
Abstraction of product flow, waste flow, elementary flow, land use, wages paid, ...
Don’t yet know if it will stick with the LCA community

Process
Model
Quantified Effect
hasQuantifedEffect
Models
Follows the SUMO upper ontology model for quantities and units
Adds the notion of an uncertainty distribution – not part of SUMO
There is a separate ontology of uncertainty distributions – they are not a logical necessity of the concept of an uncertainty distribution
What about the Zero uncertainty distribution – that is a logical necessity
Quantity
Effect
magnitude
units
Uncertainty distribution

Lake
Water
SO2
Quantified Effect
Quantity
Elementary Flow
Current LCA data structures have a fixed set of possible elementary flows, or at best a fixed set of properties of elementary flows
magnitude
units
Uncertainty distribution

Lake
Water
SO2
Quantified Effect
Quantity
Elementary Flow
ECO allows for more flexibility than that e.g. Could specify the size of the lake into which they emissions occur or provide some information about the kind of fish that live in it
Should we have allowed that extension:
giving in to the temptation to ‘improve’ the current shared conceptual model
done in a way that extends the legacy and does not contradict it
extensibility is a key advantage of the approach

Other things in ECO
Non-elementary flows – products through the supply chain
Supply chain connections
Allocations – for processes with multiple outputs
Attributes – what percentage of inputs are certified organic?
Impact assessments
Expressions and variables
Markets and other aggregations – e.g. NA Electricity
Statistical and IO data
Annotations and other metadata
Scale: 66 classes, 81 properties, 7 individuals

Other Parts
OWL Full axioms
Mostly in OWL DL – only a few FULL axioms
Bridging ontologies
To SUMO, FOAF, TIME, GoodRelations, ...
Mimimize ontological commitment
Extension ontologies
FASC, distributions, file formats, attributes, impact assessments, flow reference data, ...

Documentation
How much fun is it trying to understand a mid-to-large ontology from an OWL file?
Description and rationale
Gentle introduction
for ontologists
Defines scope and purpose
Document:
principles
examples
maybe non-examples
identity criteria
Good discipline to write down
design choices and reasons

Scope and Purpose
There is no such thing as the perfect ontology for a domain
The ontologist has to make modelling choices
Those choices are influenced by the scope and purpose of the ontology
Rings of focus model
ring 1 : model in detail
ring 2 : model lightly
ring 3 : aiming for no discontinuities
ring 4 : don’t care

Status
Study the domain
Talk to domain experts
Read
Study existing systems
Put together version 0.1
Try it out on a test application or two
Socialise it with leading community members
Seek wider community input

Earthster Reference Flows
Problem: Current databases and impact assessment methods use different vocabularies
Relevant effects get missed from impact assessments
Duplicate effects get ‘invented’
Hard: if the method specifies paraquat ion and you have numbers for paraquat
Are they equivalent?
Is there a fudge factor?

Replace lists with structure
Currently LCA databases work with lists of elementary flows and give them Ids
ECO has structure for these elementary flows:
Flowable
Energy – use source + density to identify
Substance
Chemical – use CAS numbers to identify
Isoptopes – use CAS number + atomic weight
Ores – use mix of substances
Other – adhoclist – bring in a structure if one emerges
Compartment
taxonomy
Time frame
These form a taxonomy
Using Skos rather than class structure to stay flexible
With an extensible set of modifiers

Aim ...
Much smaller lists to manage
Manage modifier attributes instead
Ability to extend the list of flows without ambiguity
Automated matching of legacy flows to the structure
Involve the community
Is there a fudge factor?
Publish reference data on the web
Crowd source corrections/updates
Relate different flows in different vocabularies through subsumption
Offers a shared resource for defining a vocabulary – that allows competition with interoperability

Summary
Making better decisions from a sustainability perspective – that’s an important problem
Open sharing of information enables market pressure to operate
Field
Somewhat fragmented
Evolving
Information rich – the value is in the data
Codifiable knowledge
Links to other data has economic value
Good space for using Semantic Web technology

Image Attributions
Hot, flickr:judepics
Industry, flickr:hans s
Crushed by the Wheels of Industry,flikr: ProblemKind
Hong Kong supermarket in Chinatown,flikr: vauvau
Crushed by the wheels of Industry 2, flikr:Problemkind
Barn Owl, flickr:AviaVenefica

Image Attributions
Offshore Windfarm Turbine, flicr:phault
Macro Leaf, flickr:seeks2dream
Spaghetti al burro, flickr:cesarastudillo
Stop, flickr:active metabolite
On Target, flickr:viZZual.com

Questions? Thoughts? Observations?

20100427 Earthster Core Ontology

by brianatepimorphicsdotcom on Apr 29, 2010

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