Development of a Wiki-based Feature Library
for a Process Planning System
Hendry Muljadi, Hideaki Takeda, Koichi Ando

Abstract—A manufacturing feature can be defined simply as ageometric shape and its manufacturing information to create the shape.
In a feature-based process planning system, feature library plays animportant role in the extraction of manufacturing features with theirproper manufacturing information. However, to manage the
manufacturing information flexibly, it is important to build a featurelibrary that is easy to modify. In this paper, a Wiki-based featurelibrary is proposed.

Keywords—Manufacturing feature, feature library, feature
ontology, process planning, Wiki, MediaWiki
I. INTRODUCTIONCOMPUTER Aided Process Planning (CAPP) offers theability to integrate a Computer Aided Design (CAD),
which allows automation of product design, and a Computer
Aided Manufacturing (CAM) system, which allows automationof manufacturing. In order to allow the CAD system tointerface with the CAPP system, feature technology has
emerged as the enabling technology to convert CAD productdata to manufacturing information [1]. Many different
approaches have been developed to extract features from the
CAD product data [2].
For the extraction of manufacturing features for thegeneration of process plans, it is necessary to develop a featurelibrary that consists of pre-defined features and the
manufacturing information to create the shape of the features[3].The manufacturing information consists of the required
machine and tool data, the estimated cost and time data, etc [4].
It is necessary to develop a feature library which is easy tomodify or to costumize, since manufacturing technologies areprogressing, and also that manufacturing information used in aparticular factory may not be the same as the other factory.
However, in general, feature libraries are not developed in a
way that is easy to modify, especially by people without
information technology background.
On the other hand, in the context of collaboration on the web,
Wiki has proven itself to be a user-friendly interface. For

Manuscript received October 15, 2005.
H.Muljadi is with the National Institute of Informatics, Tokyo, Japan(phone: 81-3-4212-2664; fax: 81-3-3556-1916; e-mail: hendry@nii.ac.jp).
H.Takeda is with the National Institute of Informatics, Tokyo, Japan (e-mail:takeda@nii.ac.jp).
K.Ando is with the Information Science and Engineering Department,
Shibaura Institute of Technology, Tokyo, Japan (e-mail: andou@
sic.shibaura-it.ac.jp).

example, the community of Wikipedia.org, the free content
encyclopedia is becoming larger and larger. There have been
more than 450,000 people who gave their contributions, either
by creating or editing articles in Wikipedia. Wiki is a
discussion medium, a repository of ideas and a tool forcollaboration. It is a simple publishing system that is easy tolearn and quick to use [5]. In Wiki, people can create or edit a
Wiki page using a simple syntax to write content. So, it isnormal to make an assumption that an extended Wiki will be
useful for the development of a feature library which is easy tomodify.
In this paper, a development of a Wiki-based feature libraryis described. The feature library consists of the function feature
ontology and the manufacturing feature ontology. Sub-classesof the function features are created based on the required
functions of the face elements that construct the features as
intended by the designers. Sub-classes of the manufacturingfeatures are created based on the existing manufacturingmethods to create the shape of the manufacturing features. To
make the feature library be useful for the extraction of
manufacturing information to create the shape of the
manufacturing features, the relation between the two ontologies
is defined. The development of the structure of the featurelibrary is described in section 2. Section 3 describes themodification of a Wiki software for the development of aWiki-based feature library. Section 4 states the conclusions
drawn from the research.
II. THE STRUCTURE OF THE FEATURE LIBRARY
A. Considering the Designer’s Intention for the Extractionof Manufacturing Features with Their Proper Manufacturing
Information
For the extraction of proper manufacturing information tocreate the shape of manufacturing features, it is important tounderstand the designer’s intention. For example, athrough-hole feature may require a cylindrical grinding tocreate the shape, while the other through-hole feature may
require threading to create the shape, depending on why thedesigner designed the geometrical shape. Thus, it is necessary
to consider the designer’s intention for the extraction of
manufacturing feature with their proper manufacturing
information.
In this research, the designer’s intention is represented by thefunctions of the face elements that construct the features. The
face element is defined as a geometrical entity that is boundedby a set of edges. The functional data of the face elements canbe described as basic function, mechanism utilized forrealization of the basic function, and condition and direction of
the motion. The detail explanation of the functional data
elements is given in other reports [6][7]. Table 1 shows thecontents of functional properties of face elements that are used
for the creation of the function feature ontology.

Basic
FunctionTransmissionof motion

Constraint of
motionFixation of
motionTABLE ICONTENTS OF FUNCTIONAL PROPERTIES
Mechanism utilzed for
Condition and direction ofrealization of the basic
the motionfunction
1: liner,
2: smooth-liner,
1: friction-mech.,
3: very-smooth-liner,
2: gear-mech.,
4: round,
3: link-mech.,
5: smooth round,
4: cam-mech.
6: very smooth round
1: liner,
2: weak-radial,
1: rigidity-mech.,
3: strong-radial,
2: ball-bearing-mech.,
4: weak-thrust,
3: sliding-mech.
5: strong-thrust
1: bolt-and-nut,
2: bolt-only,
3: friction-mech.,
1: stationary-object,
4: bearing-fit,
2: revolutionary-object
5: key-fit,
6: river-fit,
7: shrinkage-fit

B. Creation of the Function Feature Ontology,theManufacturing Feature Ontology, and the Relation Between
the Two Ontologies
Fig.1 shows the function feature ontology, themanufacturing feature ontology, and the relation between thetwo ontologies. Two steps for the creation of the function
feature ontology, the manufacturing feature ontology, and therelation between the two ontologies are as follows.
1) Creating a function feature ontology. A function feature isdefined here as a geometric shape and its functions as
intended by the designer. For the creation of a function

feature ontology, first, features such as slot, step etc arelisted up. This research uses the list of features proposed in[8]. Then, sub-classes of these features are created bydescribing the required functions of the face elements that
construct the features.
2) Creating the manufacturing feature ontology. First,
manufacturing features such as step, slot etc are listed up.
Sub-classes of these manufacturing features are created bydescribing the general manufacturing methods to create theparent classes. Sub-classes of these sub-classes are createdto have their relation with the function feature ontology.
The relation between the classes in the lowest level of the
manufacturing feature ontology and the function feature
ontology represents how the manufacturing features should
be manufactured to fulfill the required functions of the faceelements that construct the manufacturing feature.
In Fig.1, an “internal turning and milled blind-hole” featureclass is created to relate the round blind-hole feature class of the
manufacturing feature ontology with the “round blind-holewith 2 faces require: Basic: fixation, Mechanism: bearing fit,
Motion: stationary-object, 1 face requires: Basic:constraint,
Mechanism: ball-bearing, Motion: strong-thrust” class of thefunction feature ontology. This is done since the internal
turning and milling can create the round blind-hole as intended
by the designer. Then, in the development of the feature library,a collection of possible manufacturing information, such asmachine and tool data, etc for the instances of the “internal
turning and milled blind-hole” feature class should be preparedso that when a round blind-hole feature is extracted by a feature
recognition method, and the functional properties of faceelements that construct the round blind-hole feature lead to theextraction of the “internal turning and milled blind-hole”
feature class, a proper manufacturing information can beextracted automatically from the instances of the
manufacturing feature class. Thus, by developing the featurelibrary based on the proposed structure, the feature library canbe useful for the automatic extraction of manufacturing featureswith their proper manufacturing information. The automatic
Manufacturing
Feature Ontology

Function Feature
Ontology

Function
Features

Step

Slot

Manufacturing
Features

Round
Blind-Holeround blind-hole with 2 faces require: Basic:
fixation, Mechanism: bearing fit, Motion:
stationary-object, 1 face requires: Basic:constraint,
Mechanism: ball-bearing, Motion: strong-thrust

Step

Slot

internal turning andmilled blind-hole

Round
Blind-HoleDrilledBlind-Hole

Fig.1 Function Feature Ontology, Manufacturing Feature Ontology, and the relation between the two ontologies

extraction of manufacturing features with their proper
manufacturing information is very useful for the realization of amanufacturing feature-based CAPP system.
III. THE WIKI-BASED FEATURE LIBRARY
A. Semantic Extension of MediaWiki
MediaWiki is a Wiki software that is written in PHP anduses MySQL database. It is being used to run the Wikipedia
and also other encyclopedia and dictionary sites. MediaWiki isa very useful tool for collaborative content management.
An extension of MediaWiki to enable the writing of thelabeled link has been proposed [9]. This extension has enabled
the Wiki to write Resource Description Framework (RDF)
statement, which consists of subject-predicate-object triple.
The Wiki syntax is [[Term:target_page|property]]. The RDF
triple is <source_page> <property> <target_page>. Each time
the Wiki syntax is used, the Wiki engine will store the RDF
triple into a table in the Wiki database. By directly querying thetable, the labeled link relation will be displayed as follows.
1) On the source_page: -> property -> target_page2) On the target_page: <- property <- source_page3) On the property: source_page -> target_page
Fig.2 illustrates the RDF triple construction and the relationof pages displayed on the Wiki pages in the extended
MediaWiki. The extended MediaWiki as an extension ofMediaWiki has the benefit of having all the functions available
in MediaWiki as a content management system, and can beused as an editor of metadata according to simple RDF
statement.
The running system of the extended MediaWiki is available
at http://semanticwiki.jp. It uses the MediaWiki 1.3.11 version
as the base system.
Term:Homer
Edit Box

The development of the Wiki-based feature library is basedon the extended MediaWiki proposed in [9].
B. Developing a Wiki-Based Feature Library
For the development of the Wiki-based feature library,further extension of MediaWiki is done. New namespaces are
created. Namespace (“FF:”) is created to deal with the function
feature ontology, and namespace (“MF:”) for the
manufacturing feature ontology. New tables are also created in
the Wiki database to deal with the new namespaces.
For the creation of the function feature ontology, the Wikisyntax [[FF:feature_subclass|subclass]] is used (see Fig.3).
When the Wiki syntax is written on the parent class page, theWiki engine will store the RDF triple into a table which deals
with the namespace (“FF:”) in the Wiki database. By directly
querying the table, the labeled link relation will be displayed asfollows.
1) On the parent class page: -> subclass -> feature_subclass(see Fig.4)
2) On the feature_subclass page: <- subclass <- parent class(see Fig.5)
3) On the subclass page: parent class -> feature_subclass (seeFig.6)The “FF:subclass” page can be used to see all theclass-sub-class relations of the function feature ontology.
For the creation of the manufacturing feature ontology, theWiki syntax [[MF:feature_subclass|subclass]] is used. When
the Wiki syntax is written on the parent class page, the Wiki
engine will display the labeled link relations in the same way asin the function feature ontology. The “MF:subclass” page canbe used to see all the class-sub-class relations of the
manufacturing feature ontology.

Writing the Wiki syntax[[Term: target_page|property]]
to construct RDF triple[[Term: Bart|Child]]
The constructed RDF triple
Term:Homer

Term:Child

Term:Bart<source_page><property><target_page>

Display on the Wiki pages

Term:Homer-> Child -> Bart

source_page:-> property -> target_page

Term:Child

Homer -> Bart

property:
source_page -> target_page

Term:Bart<- Child <- Homertarget_page:<- property <- source_page

Fig.2 RDF triple construction and the display on the Wiki pages in the extended MediaWiki

Instance” column.
Fig.7 and Fig.8 illustrate the page relations of the function
feature ontology and the manufacturing feature ontology in the
Wiki-based feature library, respectively.
FF:Feature
Edit Box[[FF: Slot|subclass]][[FF:Step|subclass]]

FF:subclass
Feature -> Slot
Feature -> Step-> subclass -> Slot-> subclass -> Step

Fig.3 Writing the Wiki syntax [[FF:feature_subclass|subclass]]

has_Subclass

has_Subclass

FF:Step

FF:Slot<- subclass <- Feature<- subclass <- Feature

Fig.7 Page relations in the function feature ontology
MF:Feature
Edit Box

MF:subclass
Fig.4 Display on the parent class page[[MF: Slot|subclass]][[MF:Step|subclass]]

Feature -> Slot
Feature -> Step
Step -> Milled Step-> subclass -> Slot-> subclass -> Step

has_Subclass

MF:Slot

has_Subclass

MF:Step<- subclass <- Feature-> subclass -> Milled Step<- subclass <- Feature

Fig.5 Display on the feature_subclass page
has_Subclass

MF:Milled Step
MF instances
・Milled Step 1
has_Class<- subclass <- Step

Milled-Step-1
Edit Box

Fig.6 Display on the subclass pageFor the class-instance relation in the manufacturing feature
ontology, the Wiki syntax [[MF:feature_class]] is used. When
the Wiki syntax is written on the instance page, the Wiki engine
will display “Class:feature_class” on the instance page. On thefeature_class page, the instance will be listed under the “MF[[MF: Milled Step]](instance page)

Class: Milled Step

Fig.8 Page relations in the manufacturing feature ontology

To make the relation between the lowest sub-class of thefunction feature ontology and the lowest sub-class of the
manufacturing feature ontology, the Wiki syntax[[MF:manufacturing_feature_class|related]] is used. Fig.9
shows the Wiki syntax writing on the function_feature_class
page. When the Wiki syntax is written on the function_feature_class page, the Wiki engine will display the labeled link relation
as follows.
1) On the function_feature_class page: -> related ->manufacturing_feature_class (see Fig.10)2) On the manufacturing_feature_class page: <- related <function_feature_class (see Fig.11)
3) On the related page: function_feature_class ->manufacturing_feature_class (see Fig.12)
The “MF:related” page can be used to see all the relations
between the lowest sub-class of the function feature ontology
and the lowest sub-class of the manufacturing feature ontology.
The Wiki-based feature library is able to construct thefunction feature ontology, the manufacturing feature ontology,
and the relation between the two ontologies. The Wiki-based
feature library can be easily, visibly and collaboratively
modified. And since the original MediaWiki has the capability
to manage contents, it can be used to manage the manufacturing
information flexibly.

Fig.11 Display on the lowest sub-class of the manufacturing feature
ontology

Fig.12 Display on the “MF:Related” page

IV. CONCLUSION

Fig.9 Page relations in the function feature ontology

This research can be summarized as follows.
1) The feature library consists of the function feature ontology
and the manufacturing feature ontology. The relation
between the classes in the lowest level of the manufacturingfeature ontology and the function feature ontology
represents how the manufacturing features should bemanufactured to fulfill the required functions of the faceelements that construct the manufacturing feature. Bydeveloping the feature library based on the proposed
structure, the extraction of manufacturing features with theirproper manufacturing information for the generation ofprocess plans is made possible.
2) MediaWiki is modified for the development of the featurelibrary. The Wiki-based feature library is able to construct
the function feature ontology, the manufacturing feature
ontology, and the relation between the two ontologies. The
Wiki-based feature library is a very simple system, and as
one tries to modify the feature library, one may enjoy thevisible modification of the feature library.
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Fig.10 Display on the lowest sub-class of the function feature ontology

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