Creating Ontology Chart Using Economy Domain Ontologies

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					                            Creating Ontology Chart Using Economy Domain Ontologies
                                     Waralak V. Siricharoen, Thitima Puttitanun



      Creating Ontology Chart Using Economy Domain Ontologies
                                Waralak V. Siricharoen*1, Thitima Puttitanun*2
    *1, Corresponding author
                             School of Science, University of the Thai Chamber of Commerce, 126/1,
                                     Dindeang, Bangkok, Thailand, 10400
        *2
           Department of Economics, San Diego State University, San Diego, California, USA
                               waralak_von@utcc.ac.th, tputita@mail.sdsu.edu
                                         doi: 10.4156/jdcta.vol3.issue3.8

                        Abstract
                                                                  2. What is Ontology and Ontology Chart?
    Ontologies are parts of an Artificial Intelligent
advance research area where it is a very familiar topic               One of the significant characteristics of ontology is
in computer science. There are many domains of                    the hierarchical relationship between classes, as well as
interests that can utilize ontolologies to use them as the        looping or cycling of these classes. Looping in this
knowledge repository. Economy is one of the widely                case means a path which ends at the node where it
interesting topics that anyone can relate to. This                began. The connection between nodes within ontology
research simplifies ontologies concepts using economy             can represent as a graph where the nodes might be
domain to guide people in the field of economics to               completed or might not be completed. This paper will
understand how ontology works as well as to guide the             use some examples of economy ontology as a case
computer software developers to understand the basic              study to help explaining the concept of ontologies. The
concept of economy. The economy ontology is                       author will illustrate the ontology chart showing how
illustrated in ontology chart and hierarchical chart.             each class connects to each other. Some suggestions
                                                                  will be addressed in order to make ontology more
                       Keywords                                   proper.

                                                                      Ontology charts are a graphical representation of
   Ontology Economy Ontology Chart.                               partially order set graph. The major characteristic of
                                                                  ontology chart is hierarchical. The ontology chart can
1. Introduction                                                   be represented in a acyclic graph pattern. It typically
                                                                  began with drawing trees to represent hierarchies of
    Ontologies have become an increasingly important              categories. However, more general acyclic graphs are
research topic. However, it is time consuming to                  needed to represent an arbitrary partial ordering, such
construct ontologies from the beginning. Moreover,                as the subtype-supertype relation between categories.
how ontologies are used is not easily understood by               Figure 1 is a simple acyclic graph, in which some
people outside the filed. In order to fully use ontology          nodes have more than one parent. Such graphs support
to its full capacity, we need to thoroughly understand            multiple inheritances, since a node can inherit
how ontologies’ classes are interrelated and how                  properties from any or all of its parents. A common
classes’ properties are described. Unfamiliar users who           convention is to omit the arrows that show the
are not ontologies experts/developers should also                 direction of the ordering and to assume that the lower
understand the concepts behind ontologies to fully use            node represents a subtype of the higher node.[2]”
ontologies functions accurately. Therefore, the aim of                By the definition given in Wikipedia, “Ontology
this paper is to explain the concept of ontologies                charts are a graphical representation of semi-lattice
through a specific example that people can relate to,             structures”[3]. “The nodes of an Ontology chart
“economy”. The reason why we choose “economy”                     represent universal affordances and rarely represent
ontology is because everyone is a part of an economy.             particulars. The exception is the Root which is a
Therefore, explaining ontology using this particular              particular agent often labelled ‘Society’ and located on
domain should be easily understood to any general                 the extreme left of an Ontology chart. The Root is
audience. In doing so, we construct an easy to                    often dropped in practice but is implied in every
understand ontology chart illustrating how ontology’s             Ontology chart” [3]. They also describe the concept of
concepts (classes) are connected to each other by using           ontological dependency as “a relationship known
parts of the “economy” domain.                                    mathematically as a partial order set relation (poset).




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                       International Journal of Digital Content Technology and its Applications
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Posets are an object of study in the mathematical               suggests that we can also use the open source tool
discipline of order theory. They belong to the class of         called Protégé to merge the existing ontologies
binary relations but they have three additional                 description in XML, OWL and export them to UML
properties:      reflexitivity, anti-symmetry      and          1.4 which have to installed UML backend plug in
transitivity” [3].                                              before. After that you can generate class diagram by
                                                                importing UML 1.4 in form of XMI to any UML
                                                                compatible software for example Visual Paradigm or
                                                                Rational Rose. The outcome of transforming ontology
                                                                to UML class diagram is rising and more manual, this
                                                                can eliminate the time consuming process in software
                                                                engineering.
                                                                    The ontologies can be reused easily since it might
                                                                be provided online as ontology library or through a
                                                                semantic search engine; for example, swoogle, ontaria,
                                                                etc. However, ontology is mostly found in description
                                                                or text version in XML or OWL syntax. Since
                                                                ontologies can be difficult to understand by non-expert
                                                                users, this paper makes use of economy concept as an
      Figure 1. The Simple Directed Acyclic Graph               example to draw out an ontology class.
                      (DAG) 1                                       Another benefit of ontology is that it can be shared,
                                                                reused through the development of domain knowledge.
                                                                Currently, there are many ontologies editor available;
                                                                however, Protégé might be the tool that is easiest to
                                                                understand among other ontology editors such as
                                                                OntoEdit, Ontolingua, and Chimaera. As explained by
                                                                the Protégé official web site, “Protégé is an open-
                                                                source tool developed at Stanford Medical Informatics.
                                                                Protégé is one of the most widely used ontology editors
                                                                with currently. Its extensible open-source platform
                                                                supports several ontology file formats including CLIPS
               Figure 2. the Ontology chart 2                   (Protégé’s native format), various XML dialects,
                                                                databases, DAML + OIL (DARPA Agent Markup
    Moreover, there is a prototyping generation from            Language + Ontology Inference Layer), and RDF(S).
ontology chart in order to create class diagram by [4]          Very recently, storage plug-ins or the Unified
as can be seen from the figures above that “for                 Modeling Language UML and OWL have been
generating prototypes were implemented in an open               added”. Protégé is an open source ontologies editor and
source software tool developed at 2006 by the Authors,          knowledge-base framework [6].               “Protégé can
called Semantic Analysis Toolkit (SAT). SAT provide             represent ontologies consisting of classes, properties
a graphical interface implemented in Java Swing that            (slots), property characteristics (facets and constraints),
allow that designer to drag and drop affordances and            and instances. And it can be used to load, edit and save
form an Ontology Charts. The tool then can evaluate             ontologies in various formats, including RDF, XML,
the chart against the basic rules of semantic analysis          UML, relational databases, and OWL”[7]. Currently,
spotting basic mistakes and produce a prototype.                Protégé serves more than 150,000 community users.
Extending an existing prototype is also possible. The
tool can read the ’Universal’ table of an already               3. “Economy” Domain and its explanation
existing system and extend its schema by adding new
affordances. This will not affect the legacy system. The            One of the definitions of “Economy” in a dictionary
tool can also produce an XMI file that can be imported          is the management of the resources of a community or
by MDA tools, if the users decide to use the MDA                a country with a view to its productivity. We can think
approach instead.” The approach of Sirichareon[5]               of an economy as a social system of production,
                                                                consumption, and distribution of goods and services in
1
  http://upload.wikimedia.org/wikipedia/commons/0/08/           an area. An economy does not have to be specific in
Directed_acyclic_graph.png                                      size since we can talk about an economy of a city, a
2
  http://en.wikipedia.org/wiki/File:Ocw.jpg                     country, or the world. Given the above definition, we
                                                                can see that an ontology domain that describes an



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                           Creating Ontology Chart Using Economy Domain Ontologies
                                    Waralak V. Siricharoen, Thitima Puttitanun


economy must include a wide range of objects that               chart. However, from the computer science
describes not only the types of the systems an economy          perspectives, we need to see more details showing the
is run on (whether it is a market economy or a                  economy objects and the relationships among them.
controlled economy), but also economic agents that
involve in the process of production, consumption, and
distribution, and the goods and services that are
produced, distributed, and consumed. Moreover, the
domain should include a measure of economic
activities. These measures can be used to describe the
value (price) of a product or service where it can be in
a form of different country’s currencies. Some
measures are used to describe how well an economy is
doing by measuring the size of production of goods
and services that a country can produce in a specific
year (gross domestic product, GDP) or measuring how
many people are unemployed in percentage term
(unemployment rate) or measuring how price of
products and services change in a given year (inflation
rate).
    In order to explain interactions between economic
agents in a simple way, we can rely on an
uncomplicated chart that can be found in most of the
principles of economics textbook such as Figure 3. The
chart explains that households (consumers) purchase
goods and services from firms (producers), generating
a flow of money to firms and a flow of goods and
services to households. The money also flows back to
households as firms purchase factors of production
from the households in factor markets (households
supply labor needed to produce goods and services).




   Source: Microeconomics 1st edition, Paul Krugman
         and Robin Wells, Worth Publisher.
         Figure 3. The Circular-Flow Diagram


    Next, we compare the Economy concept to what is
available in the Economy Ontology provided online
and displayed in Protégé as shown in Figure 4. As can
be seen from Figure 3, only the main major objects
(households, firms, goods and services, money, and
factors of production) are shown in the Economy flow



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                        International Journal of Digital Content Technology and its Applications
                                         Volume 3, Number 3, September 2009


       Figure 4.1, 4.2 Economy ontology 3 displayed in
                    Protégé version 3.4

    Economy Ontology in Protégé 4.0, as seen in
Figure 4, shows the hierarchical relationship of the
economy ontology. As seen above, there are many
significant classes. For example, class Agent is
composed of Producers, Consumers, and Governments,
which are the main characters within any economy.
This Agent class has no subclass (Subclass is a lower
class of child class which is can be inherited all the
properties of upper class called superclass or parent
class). An example of Goods and Services circulated in
an economy is such as class Beverage, where Wine is a
subclass in it. To represent a Market, an ontology class
can list countries for that purposes. In order to
purchase any goods and services in a market, we need                Figure 6. Object Properties (Industry Attributes) of
to use Money, which has a unit listed in different                                Geopolitical Area
currencies used in each market, such as British Pound,
or US dollar, etc. In order to produce those products to             We can interpret some parts of classes shown in
distribute in the market, we need to use inputs or factor        Protégé to the Class hierarchy in order to make it easier
of production such as workers that is listed in the class        to understand. However, even when it can explain the
Factor Market.                                                   main concepts in the economy (Figure 3) almost
                                                                 completely, Figure 7 still shows different points of
                                                                 view of an economy between an economics perspective
                                                                 and computer science perspective. The main difference
                                                                 is in the concept of how to divide each item into levels.
                                                                 An economy in economics perspective does not
                                                                 necessarily have to be divided in hierarchical format
                                                                 since they are intertwined in many levels rather than
                                                                 just a one to one mapping like what shown in Figure 7.

                                                                     However, some relationships provided in ontology,
                                                                 are not a one-to-one mapping. By showing them in
                                                                 class hierarchical would not describe the correct
                                                                 information. Therefore, it is necessary to show multiple
                                                                 inheritances in ontology.




                   Figure 5. Data Properties




3
    http://reliant.teknowledge.com/DAML/Economy.owl




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                        Creating Ontology Chart Using Economy Domain Ontologies
                                 Waralak V. Siricharoen, Thitima Puttitanun




                                       Figure 7. Economy Class hierarchy

                                                              As mentioned above, even though the hierarchical
                                                          chart can clearly define the relationship between
                                                          classes, it is difficult to incorporate the multiple
                                                          hierarchical link and would complicate the chart
                                                          further. Therefore, in the case where some classes are
                                                          contained in several super classes or have more than
                                                          one subclasses, the best way to show those
                                                          relationships is to use an “ontology chart” such as one
                                                          depicted in Figure 9. Ontology chart can show how
                                                          classes are connected through hierarchical patterns as
                                                          well as graphing patterns. Subclasses in ontology can
                                                          have more than one super classes, which is called
                                                          multiple hierarchical inheritances (see DAG graph in
                                                          Figure 1). In other words, the lower classes can be
                                                          inherited all properties from more than one super
                                                          classes.
                                                              From Figure 9, we can see that the class Industry
                                                          Attribute has three super classes, which are Rational
                                                          Attribute, Object, and Geopolitical Area. Moreover,
                                                          some classes can be an instance of more than one super
                                                          classes. For example, British Pounds and Canadian
                                                          dollar are subclasses of Currency Measure class as
                                                          well as the Unit Of Measure class.
    Figure 8.1, 8.2 British Pound is a subclass of
Currency Measure and an Instance of class Unit Of
                    Measure




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                     International Journal of Digital Content Technology and its Applications
                                      Volume 3, Number 3, September 2009




                                     Figure 9. Partial Economy Ontology Chart

4. What is missing from “Economy”                                There are many ontology editors, for example,
Domain? How to edit ontology using                           Protégé, OntoEdit, KAON, Swoop, Semantic Turkey
                                                             that allow developers to edit ontologies. Focusing on
Protégé?                                                     the Protégé, currently, there are two versions
                                                             available to download, and it is an open source
    The economy ontology gives some basic ideas of           developed using java. There are more than 150,000
how classes are related to each other in ontologies.         registered users that help develop ontologies and
On an important concept, such as an “Economy,”               solve problems that may occur in Protégé. In the case
there generally are more than one ontologies created         that we find a more detailed ontology in a related
on the basic of economy. Since different groups of           topic to Economy, such as Economy-Government
developers create their own economy ontology, many           ontology, we can merge the two existing ontologies
times they are different. Furthermore, there are             together using Protégé conveniently as shown in
always some missing concepts or relationships or             Figure 10.
even classes in different ontologies. For example, in
one ontology, Exporting is an object property of two
classes: Financial Transaction and Change of                 5. Conclusion
Possession where Change of Possession can be
associated with other classes such as Importing and             Since the ontology concept are not easily
not restricted to only Exporting. Therefore, one             understood by people outside the filed, this paper
might want to be able to adjust, edit, or combine            explain how ontologies’ classes are interrelated and
ontologies, to make it more complete.                        how classes’ properties are described using a specific
                                                             example “economy”. We construct easy to
                                                             understand charts, both hierarchy chart and ontology




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                           Creating Ontology Chart Using Economy Domain Ontologies
                                    Waralak V. Siricharoen, Thitima Puttitanun


chart to illustrate how ontology’s concepts (classes)
are connected to each other by using parts of the
“economy” domain. However, each ontology might
have missing super classes, classes, and subclasses                                              This part that
that we can borrow from another ontology concept.                                                come from
Therefore, the ability to edit and merge existing                                                Economy-
ontologies are very important and crucial to develop a                                           Government
complete ontology without redesigning it from the                                                Ontology
beginning.

                                                                                                         This part
                                                                                                         that come
                                                                                                         from
                                                                                                         Economy
                                                                                                         Ontology




                                                               Figure 11. Merge result of Economy –Government
                                                                      Ontology and Economy Ontologies

                                                              6. References
                                                              [1] http://en.wikipedia.org/wiki/Directed_acyclic_graph
                                                              [2] John F. Sowa, 01/18/2009 Building, Sharing, and
                                                                  Merging Ontologies
    Figure 10. Economy –Government Ontology 4                     http://www.jfsowa.com/ontology/ontoshar.htm 19
                                                                  March 2009
                                                              [3] http://en.wikipedia.org/wiki/Ontology_chart
                                                              [4] Poernomo, I., and Tsaramirsis, G., “Prototype
                                                                  Generation from Ontology Charts” the Fifth
                                                                  International Conference on Information Technology:
                                                                  New Generations, March 17, 2009
                                                              [5] Siricharoen W. V., “Merging Ontologies for Object
                                                                  Oriented Software Engineering”, Proceedings of the
                                                                  2008 Fourth International Conference on Networked
                                                                  Computing and Advanced Information Management -
                                                                  Volume 02 NCM2008, pp 525-530.
                                                              [6] http://protege.stanford.edu/download/ontologies.html
                                                              [7] Fergerson, R.W., Noy, N. F., and Musen M. A., “The
                                                                  Protégé OWL Plugin: An Open Development
                                                                  Environment for Semantic Web Applications”,
                                                                  October 19, 2004 Volume 3298/2004, pp 229-243.




4
 http://reliant.teknowledge.com/DAML/Mid-level-
ontology.owl




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