GUITAR HERO, a Knowledge-Based System to
Support Creativity in the Design and Manufacturing of
Electric Guitars
Stefania Bandini, Andrea Bonomi and Fabio Sartori
University of Milan, Italy
This paper presents GUITAR HERO, a knowledge-based system to support
experts of a handicraft enterprise involved in the design and manufacturing of electric guitars characterized by an aluminum body. The domain of the project is extremely innovative, because electric guitars are typically manufactured exploiting
different kinds of wood rather than metals like aluminum, or other materials. To
this aim, an ontological representation of the electric guitar has been implemented
exploiting NavEditOW, a computational framework for the codification, navigation and querying of ontologies over Internet, based on the OWL language. This
representation is the main subject of the paper together with a description of the
domain and a brief state of the art.
Introduction
In this paper we present a knowledge-based approach to support the decision making process of experts involved in the design and manufacturing
of electric guitars, in the context of the GUITAR HERO project.
The project is a collaboration between CSAI1 and NOAH GUITARS2,
an Italian Small-Medium Enterprise leader in the production of high quality guitars. An electric guitar is a complex product made of the following
parts: Body, Bridge, Pickups, Volume and Tone Control, Neck, Headstock,
1
2
www.csai.disco.unimib.it
www.noahguitars.com
J.S. Gero and A.K. Goel (eds.), Design Computing and Cognition ’08,
© Springer Science + Business Media B.V. 2008
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S. Bandini, A. Bonomi, F. Sartori
Trussrod, Frets, Hardware. Each part has a precise function and some of
them influence others. For example, Body is the main part of the guitar;
different from an acoustic guitar, the Body of an electric one has a significant role from the sound point of view, but it is also responsible for connecting all other components.
While electric guitar bodies are traditionally made of wood, NOAH guitar body design and manufacturing are based on the adoption of aluminum.
This is due to many reasons: First of all, aluminum is an inert material,
thus it is less subject to deformations than wood; moreover aluminum has
interesting properties from the quality of sound point of view. NOAH experts have noticed that the use of aluminum allows avoiding the generation
of noises that are typical of wooden guitars, e.g. when equipped with single coil pickups.
There are also interesting advantages in the production process: an aluminum body is produced starting from a CAD model that is the input for a
dedicated machine. The CAD model allows the definition of a very precise
morphology of the final product, by identifying the location of pickups,
controls and other components to be mounted on the body as well as the
position of the neck.
The aim of the GUITAR HERO project is to build a knowledge model
of the decisional process of NOAH experts. In order to do this, we have
decided to follow the methodological approach exploited in the IDS project [7], with the definition of three different levels of knowledge to be acquired and represented:
• Ontological Knowledge, related to the definition of functional relationships [2] among guitar parts;
• Procedural Knowledge, related to the description of how the guitar
components are manufactured starting from the CAD model, as well as
which factors influence the different steps of the process (e.g. what kind
of relationships exist between technical and aesthetical requirements
coming from guitar players;
• Experiential Knowledge, devoted to represent into a homogeneous conceptual framework the heuristic rules adopted by the different kinds of
expert involved.
In this paper, we will describe how we are building the GUITAR HERO
knowledge based system following the methodological approach briefly
introduced above. In particular, after an exhaustive description of the project domain, we will describe the different steps of the knowledge acquisition and representation campaign we are conducting with NOAH experts.
Moreover, details about the computational approach we are following to
develop the final system will be given, focusing on the computational tool
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[3] adopted for the development of ontological, procedural and experiential knowledge.
The Electric Guitar: a Complex Product
The guitar is a relatively recent kind of musical instrument: the first models of guitars where built by Antonio Torres Jurado in the 19th century. The
guitar acquires importance in the 20th century and, in particular, in the period between 1930 and 1950, when American manufacturers like Fender
and Gibson give very important stimulus to the development of guitar
acoustics.
A real point of break is the birth of electric guitars, whose acoustic
properties depend on specific electric components rather than on properties
of materials and guitar morphology. These components are called pick-ups,
and they are able to “capture the vibrations” of strings moved by the player
conveying them to amplifiers.
An electric guitar is generally composed of the following parts (see
Figure 13): (1) body is the main part of the guitar, where the pickups and
bridge are located; (2) bridge is an area of the guitar through which the
strings are connected to the body. Very often, strings are placed on saddles. Saddles are configurable and can be single (i.e. each saddle is
devoted to the connection and regulation of one and only one string) or double (i.e. each saddle is devoted to the connection and regulation of two
strings). There exist many different kinds of bridge, some of the most used
are tremolo bridges, (e.g. Wilkinson or Bigsby), adjustable bridges and
fixed bridges; (3) frets are vertical metal wires that sit vertically on the guitar neck; (4) headstock is the area of the guitar at the end of the neck where
the strings are fixed and tuned; (5) neck is the long narrow part of the guitar where notes are fretted. Located between the body and headstock of the
guitar, the neck is usually a wooden part: to limit negative effects of deformations, an adjustable steel bar named trussrod is placed inside it. The
trussrod can be adjustable at the headstock or adjustable at the body; The
trussrod can be adjustable at the headstock or adjustable at the body; (6)
Nut is the point on the guitar neck where the strings touch the neck and
join the headstock;
3
Picture extracted from http://www.maximummusician.com/Anatomy.htm
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Fig. 1. The main components of an electric guitar.
(7) pickup switch is a switch located on the body of the guitar used to
select different pickups for different tones and sounds; (8) pickup is a
magnet wrapped in copper wires that sits on the face of an electric guitar,
underneath the strings. When the strings move, they interfere with the
magnetic field of the pickup, and that impulse is sent to the amplifier.
There are many kinds of pickups according to the number of coils they are
made up of. Typically, single-coil (more subject to noises) or multi-coil
(humbackers) (less subject to noises) pickups are adopted; (9) tremolo (i.e.
Whammy Bar) is a bar connected to the bridge of the guitar. By moving
the tremolo bar up or down the bridge moves consequently, thus changing
the pitch by loosening the tension of strings (10) tuning pegs are the pegs
located at the headstock, which are used to tune the guitar. The machine
heads have gears that can tighten or loosen the string when turned; (11)
volume and tone control are Control knobs located on the body of the guitar and used to adjust guitar volume and tone.
In the next section, we’ll describe the object of the Guitar Hero project,
that is an aluminum guitar designed and manufactured by NOAH, an Italian Small-Medium enterprise that creates handicraft guitar used by some
of the most famous players in the world.
Aluminum Guitars versus Wooden Guitars: The NOAH Case
Study
Generally, electric guitars’ components are made of different kinds of
wood (e.g. rosewood, maple tree) according to their function. This is due
to both historical reasons (in ancient time, wood was the only suitable material) and practical ones (touching wood is a pleasure for players’ hands,
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wood is light). The usage of wood has some drawbacks: first of all, wood
is an “alive material” that modifies its characteristics. To avoid such problems, wood that is employed in the manufacturing of electric guitars is
typically seasoned and expensive.
Another problem of wood is that it can be damaged very easily in case
of collisions. In order to solve such problems, guitar manufacturers have
experimented with other materials. In particular, metals are considered
good substitutes of wood, since they are not deformable. Unfortunately,
the adoption of metals leads in most case to obtain too heavy products.
Moreover, metals are cold and they cause bad feelings in guitar users who
touch them when playing.
For these reasons, wood is still the most suitable raw material to use in
the manufacturing of electric guitars. Some exceptions can be found:
NOAH Guitars is the Italian leader in the design and manufacturing of
aluminum guitars. NOAH experts have devised a process to produce guitars with characteristics very similar to more traditional ones exploiting
their know-how in working with aluminum.
Fig. 2. A NOAH guitar with aluminum body.
It is important to notice that the NOAH method concerns the design and
manufacturing of guitar bodies: other parts, like e.g. neck and headstock
are still made of wood. The body is obtained from a unique piece of aluminum that is roughly processed by a Finite Element Machine according to
a CAD model that defines body features. The result is a hollow body
where other guitar components (pick-ups, bridge, volume and ton controls,
and so on) will be located. The body is then refined in order to delete imperfections, to round off edges and make aluminum polished. An example
of a typical NOAH guitar is shown in Figure 24.
4
Picture extracted from http://www.noahguitars.com
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NOAH experts: a community of practice
NOAH guitars have reached an excellence level form many points of view.
First of all, the adoption of aluminum as the main raw material instead of
wood provides NOAH guitar bodies with a natural capability to minimize
noises due to the interference caused by pickups. Although these noises are
less important in electric guitars, this is indeed an advantage.
Moreover, aluminum bodies can be maintained very easily: since the
body is a sort of box where most of the functional parts of the guitar are
placed (e.g. bridge, pick-ups, controls), the body has been designed and
manufactured in order to allow an easy access to such components in case
of need, for example to substitute a broken part. While this is difficult in
case of wooden guitars, since wooden bodies are built-up starting form a
unique piece of wood, without junctions, NOAH guitar bodies are made of
two distinct parts, the frontal container and a cover that is fixed to the
frontal container by means of screws. In this way, it is really simple to
manage other components of the guitar by removing the cover. This kind
of solution is not applicable to wooden guitars, since the body profile is
too thin to allow the realization of holes for screws.
Another important innovation by NOAH experts is their attempt to reduce the bad feelings in players due to the contact with cold surfaces, both
from the manufacturing process and raw material adoption perspectives.
The last phase of the manufacturing process is anodizing, through which
the aluminum assumes characteristics less unfamiliar in terms of touching
perception by the user. Moreover, NOAH expert research is continue in the
field of raw material testing, with the experimentation of new types of
aluminum and their adoption in case of success.
Finally, NOAH electric guitars are appealing from the aesthetic point of
view too. Aluminum is buffed by hand in order to delete imperfections and
also the mounting of other components like pick-ups and bridges on it are
the result of deep analysis.
Thus, we can say that the final product is the result of an intense negotiation process among NOAH experts where three distinct competencies
emerge:
• Functional competencies, concerning the property of the guitar from the
playing point of view, like e.g. the reduction of noises;
• Procedural competencies, concerning how to design the body exploiting
CAD technologies in order to properly feed machineries that will produce them starting from pieces of aluminum and preserving its functional
features;
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• Aesthetic competencies, related to the design of guitars that can be appealing for a customer and can characterize them as artistic objects as
well as good musical instruments.
Each of these competence is owned by subgroups of experts in NOAH,
where it is possible to identify people skilled in playing guitars who is able
to recognize benefits/drawbacks on the sound quality coming from the
adoption of a specific design choice, people whose expertise is in the field
of aluminum and people with deep know-how in the design of artistic
objects.
The interest on NOAH from the Knowledge Management perspective
derives from the nature of collaboration among these people to make possible to integrate all competencies into a unique final product and that
makes possible to classify NOAH as a Community of Practice (CoP) [19].
In fact, functional, procedural and aesthetic competencies are not considered in a synchronous way during the design and manufacturing of a
new product, but as different and complementary aspects of the same problem. For this reason, the task to produce a new guitar is not considered as
sequence of atomic steps but as a negotiation process during which each
competence is taken into account at the same time.
Thus, we can state that creativity in the context of NOAH is the capability of people belonging to the CoP to uniformly consider the different aspects of the knowledge involved that results into the reification of a concrete object that meets both functional and aesthetic requirements
according to a manufacturing process that allows to preserve it.
The aim of the GUITAR HERO project is the development of a knowledge-based system that allows modeling the essence of this negotiation in
order to support NOAH experts in the exercise of their creativity. The
GUITAR HERO project aims at the acquisition, representation and codification of different kinds of knowledge involved in the design and manufacturing of electric guitar through the adoption of suitable knowledge
engineering tools. In particular, this paper focuses on the representation
of functional knowledge by means of ontologies, which is the subject of
following sections.
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Knowledge Management to Support Creativity: an Ontological
Approach
State of the art
In the last years both the scientific and the industrial communities recognized the role of semantics for knowledge management, access and exchange. Semantic based approaches have been applied e.g. to information
retrieval, system integration and knowledge sharing structured as semantic
knowledge bases.
A lot of research has been carried out, a great number of theoretical results have been achieved (see e.g. [10][12]) and a number of applications
have been developed [16].
OWL5 has become a standard language for defining ontologies, providing a common way to automatically process and integrate information
available on the Web. OWL allows defining ontologies constituted by
classes, properties and instances.
Despite these efforts and enhancements, a number of open problems still
prevent semantic based technologies from being effectively exploited by
end users; end users in fact cannot be assumed to have formal skills that
are required nowadays to interact with semantic KBs, with respect to both
the contribution to the KBs growth (i.e. its update and maintenance) and
the access to the KBs content on the basis of its semantics (i.e. through
query and navigation).
For this reason, the development of systems that improve the access to
ontological KBs, in both the updating and the retrieval and discovery of information phases, is a challenging topic in order to meet knowledge management systems users perspective.
In order to develop the user interface, many ontology editors and visualization tools have been investigated. In our opinion, these applications
are critical, since the diffusion of Semantic Based Knowledge Management Systems and more generally Semantic Web applications depends on
the availability of convenient and flexible tools for editing, browsing and
querying ontologies.
Before developing a new system, we have analyzed the principal tools
of this area. One of the most popular ontology editor is Protégé. It is a free,
open source ontology editor and knowledge-based framework. A detailed
description of Protégé is out of the scope of this paper and can be found in
5
OWL Web Ontology Language – http://www.w3.org/TR/owl-features
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[13]. Protégé allows editing of ontologies expressed in OWL. In our opinion, Protégé is one of the best OWL editor, but its user interface is too
complex for a user with no experience of ontological languages and lacks
some useful functions like the inspection of the elements (e.g via hyperlinks) and comfortable edit/visualization facilities for the individuals.
Fig. 3. NavEditOW Web Interface.
An interesting Web-based OWL ontology exploration tool is OntoXpl,
which is described in [14]. In particular, an interesting feature of OntoXpl
is the visualization facility for individuals that can be displayed as a tree
whose nodes are individuals and arc are properties. This kind of visualization is suitable for A-Boxes with many individuals. OntoXpl also supports
the inspection of the ontology elements via hyperlinks. Swoop [11] is a
hypermedia inspired ontology editor that employs a web-browser metaphor for its design and usage. All ontology editing in Swoop is done inline
with the HTML renderer (using color codes and font styles to emphasize
changes); it also provides a querying interface for ontologies.
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S. Bandini, A. Bonomi, F. Sartori
NavEditOW: a tool for navigating, editing and querying ontologies
over the web
General Description of the Tool
NavEditOW (see Figure 3) allows exploring the concepts and their relational dependencies as well as the instances by means of hyper-links;
moreover, it provides a front-end to query the repository with the
SPARQL6 query language. The main functionalities offered by NavEditOW are the navigation, editing and querying of OWL ontologies through
a web-based interface.
In the following paragraphs, we present more details about each of these
tree basic functionalities supported by the application. With the ontology
navigation interface the users can view ontology individuals and their
properties and browse their properties via hyperlinks. Browsing the ontology is essential for the user in order to explore the available information
and it also helps not expert users to refine their search requirements, when
they don’t start from any specific requirement in mind [17].
Application to the Guitar Hero Project
The hierarchical organization of the different concepts and individuals of
the ontology is graphically represented as a dynamic tree. The aim of the
navigation tree is to explore the ontology, view classes and instances, discover the relation between them.
The tree does not represent only a hierarchy of classes connected by IsA binary relations (shown in Part A of Figure 4), but also tree-like connections of individuals for domain dependent classes of properties (e.g. PartOf, isMadeOf, and so on). Both visualizations (Is-A relations between
classes and domain-dependent relations between instances) are useful for
users, since they provide them with a view of the ontology from two different perspectives: The parts of a guitar can be considered as classes connected by Is-A relation (e.g. a Potentiometer is an Electronic Component,
an Electronic Component is a Hardware Component, a Hardware Component is a Main Component and so on).
As an example, shown in Part B of Figure 4, the parts of a “physical”
guitar can be linked to the guitar by a Part-Of relation. In this way, it is
possible to group components under the sub-tree representing the main
6
SPARQL is a RDF Query Language standardized by the World Wide Web Consortium – http://www.w3.org/TR/rdf-sparql-query
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part they are all subparts of (e.g. starting from a guitar instance, it is possible to reach the potentiometer through the slim body node).
Fig. 4. Part A: the Is-A-Tree of the guitar ontology, where each componente is
ideitfied by a yellow circle. Part B: The Part-Of-Tree of the guitar ontology, where
each part is identified by a violet rumble.
The root of the navigation tree is the OWL class Thing, and the rest of
the tree is organized as follows: Under the root node, there are the toplevel classes (i.e. direct subclasses of Thing); each class can be expanded
to show its subclass hierarchy and its individual members; individual-toindividual tree connections are defined according to a number of selected
properties (e.g. Part-Of).
In order to distinguish between classes and individuals, they are represented with different colors and markers: a yellow circle for the classes, a
violet square for the individuals. More individual properties (e.g. MadeOf,
not shown in the figure) are considered by the system and blue squares are
used to represent them. In order to simplify the adoption of the NavEditOW for the Protégé users, we selected the same colors of the Protégé user
interface.
The application allows the users to create, edit and remove individuals
of the ontology, their properties and, in particular, their labels. In fact, to
ensure multi-language support, it’s possible to introduce several labels in
different languages for every instance. Moreover, contextual editing, that
is, the editing of individuals while browsing the ontology, is supported.
Although end-users may not be familiar with query languages, the possibility to perform expressive queries is supported. From one hand, a language as much as similar to well-known query languages for relational
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databases language should be preferred. On the other hand, interfaces
enabling not expert users to query the ontology should be developed (e.g.
query forms).
Fig. 5. A high-level view of the guitar ontology briefly introduced above. Classes
are represented as circles connected by Part-of relations.
First, one kind of query interface is the SPARQL free query form, where
users can write queries in the SPARQL language, display results in paginated tabular form and navigate through results via hyperlinks. This interface is very flexible because the users can write arbitrary queries but is not
suitable for end users who are not expert on the ontology domain.
Another kind of query interface is based on a pre-defined set of queries:
Each query is composed of a description in natural language, a SPARQL
query with optional parameters. Every parameter has a label, a type and,
eventually, a restriction on the values (e.g. a parameter can only be valued
with instances of a given class). For this interface, users can select a query
by its description, define the query parameters’ value and execute it.
GUITAR HERO Functionalities
Through the exploitation of a tool like NavEditOW, OWL ontology could
be used like a database, to store, search and retrieve information. Moreover, representing the guitar domain as OWL ontology is useful:
• To explicit the domain representation;
• To generate the Bill Of Material (BOM);
• To make automatic classification of guitar models.
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Fig. 6. An example of Consistency Check on GuitarModel1.
The explicit representation of the domain with OWL, as shown in Figure 5, allows describing every concept with a formal language and to give
each term a unique an explicit definition. This definition could be shared
within the enterprise, among experts, suppliers and clients.
Moreover, exploiting an OWL consistency checker it is possible to
check the consistency of the ontology (see Figure 6). For example if we
would assert that every guitar must have only one neck and a particular
guitar has more then one neck, a problem will be detected and notified.
This is a really simple example; in real cases, having to deal with larger
ontologies, to find inconsistencies is a hard task for a human.
With an ontological representation of the components constituting a guitar, it is possible to automatically generate the complete set of the physical
elements required to manufacture the product. The generated Bill of Material (BOM) accurately lists all parts and raw materials needed to make a
unit of product, as depicted in Figure 7. An interesting aspect is the flexibility of this ontology-based BOM: For instance, if we would assert that a
Guitar Body requires a Bridge, we will be able to choose either a Bigsby or
a Fixed Bridge.
It will be possible to select istances of both classes because both Bigsby
and Fixed Bridge are subclasses of Bridge; thus, an OWL reasoner will be
able to infer that the instances of subclasses are also instances of a superclass.
Another feature provided by OWL, and inherited by NavEditOW, is the
ability to automatically classify the instances of the ontology. In the guitar
domain (see Figure 8), a “LowNoiseGuitar” has been defined as a guitar
with an aluminum body or a guitar with a multi-coil pickup. NavEditOW is
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able to discover every guitar with these features and to assert that it is a
low noise guitar.
Fig. 7. Example of Bill Of Material generation.
One more example: a “FineTuningGuitar” is defined as a guitar with
single saddles or Trussrod adjustable on the Headstock. The first definition concerns the regulation of strings: As introduced above, single saddles
allow a more precise regulation than double ones. The second definition
regards the regulation of Neck against deformations according: Trussrod
adjustable on the Headstock is more efficient than Trussrod adjustable on
the Body. Every guitar with at least one of these features is an instance of
this class.
Since the two classes “LowNoiseGuitar” and “FineTuningGuitar” are
not disjointed, a guitar can be classified at the same time low noise and fine
tuning.
Fig. 8. Automatic Classification. The reasoner infer that Body001 is an instance of
AluminumBody and, thus, Guitar001 is an istance of LowNoiseGuitar.
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A Use Case
In order to understand the improvement given by the knowledge based approach to support the decision making process in the design and manufacturing of electric guitars, it is useful to present a use case, shown in Figure
9. Let’s suppose that a customer asks to NOAH a guitar with specific features: a low noise guitar. NOAH has two possibilities to meet requirements: searching for an existing guitar with such feature in the ontological
repository or designing a totally new guitar.
Generally, a good choice could be to check the existing archive of products and decide to build a new one if and only if there is no product presenting the required features. NOAH can extract the list of the individuals
belonging to the “LowNoiseGuitar” class. Thanks to the automatic classification provided by NaveEditOW, all the guitars that are classified as
“low noise” will be inferred as a set of instances of the “LowNoiseGuitar”
class. If the set would be empty, NOAH will be notified and can decide to
build a totally new guitar.
Otherwise, NOAH will be able to select a guitar class from the ontology, compute the Build of Material and select all the components. Then,
the system will check for the selection of all the required components, and
eventually notify the user in case of omissions. The new guitar will be
automatically added to the ontological repository, so that it will be chosen
in the future if a new customer requires a guitar with the same features.
Fig. 9. Use Case.
Discussion
The GUITAR HERO project can be considered from different perspectives, as (1) knowledge based system concerning an innovative domain, (2)
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a design support system, (3) a system for the preservation of cultural patrimony and creativity of handicraft and small-medium enterprises.
About the first point, it is important to highlight that guitar domain has
been already explored by Computer Science (see e.g. [11]), but previous
works in this field were mainly characterized by the analysis and reproduction of fingering methods for learning systems [5], classification of playing
styles [4][6] or tablature generation for electronic simulation of melodies
[8][15] rather than the attempt to build complete knowledge models for
supporting the manufacturing of products.
With respect to the cited works, the GUITAR HERO project is devoted
to the application of knowledge engineering and management techniques
rather than traditional CSP and Vision-Based ones adopted in this field.
About the second point, the main interesting feature of GUITAR HERO
project is the adoption of ontologies for representing complex objects from
the functional point of view. In this sense, the project exploits a conceptual
framework [1] already tested in the past [2][7]. This framework is very
suitable to deal with design and manufacturing problems, because it allows
giving a complete representation of sub-systems a complex object is composed of, describing their role in delivering functionalities.
The third issue is probably the more interesting, since it concerns the
development of support systems for organizations characterized by scarce
level of computer science technology.
Indeed, the real innovation of the GUITAR HERO project is the product
it is focused on, that is the result of a completely handicraft manufacturing
process. The challenge is how to build an effective knowledge based system for a problem where no formal representation of the decision making
process is available, and creativity of experts is the key factor for success.
The functional representation adopted allows describing the properties
of a complex object as they emerge from the underlying structure of relationships among functional subsystems: in this way, the system is able
to classify the request of a NOAH customer according to the archive of
already manufactured products, suggest which kind of raw material or semimanufactured parts to buy and keep NOAH people in touch with collaborators, like guitar players or makers of stringed instruments.
Conclusions and Future Works
This paper has presented the GUITAR HERO project, collaboration between the Research Center on Complex System and Artificial Intelligence
of the University of Milan-Bicocca and NOAH Guitars.
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The project scope is the design and implementation of a Knowledge
Based System for supporting creativity of NOAH experts in designing and
manufacturing electric guitars with aluminum bodies.
The decision making process in this field involves different kinds of
knowledge, which must be properly captured in order to understand how
the different components of the guitar can be related to each other, influencing final product features. In this sense, the adoption of ontologies as
conceptual framework for the representation and integration of knowledge
is strategic, as well as the development of a ad-hoc tool, named NavEditOW, to guarantee their easy navigation and management.
Moreover, the adoption of NavEditOW has been made to allow an easy
and quick access to the system through Internet. NavEditOW is a tool for
the navigation and query of ontologies over the World Wide Web. This
possibility is indeed a great benefit for NOAH, that will lead to a more efficient management of orders to suppliers, communication among people
and so on. Anyway, this is object of future works at the moment, since we
are still evaluating how to modify the NavEditOW interface to this aim.
It is important to notice that the functional representation of the guitar is
not present in the current version of the ontology: a knowledge acquisition
campaign started recently in order to cover this issue by the identification
of functional systems within the guitar. Table 1 illustrates some of such
functions and functional systems.
Table 1 Functions and functional systems in the Guitar Hero project
Function
Definition
Precision
the guitar capability to Bridge, neck, strings
maintain the string tuning when solicited in a
hard way
the guitar capability to Body, neck
be played comfortably
Usability
Timbre
Functional System
Components
the distinctive property Bridge, pickup, tone
of a guitar sound
and volume controls,
strings
The definition of function and functional systems is crucial to guarantee
usage flexibility of the system by the user, since it allows enriching the
guitar ontology with transversal relationships among parts. In this way, the
user can be guided in definition of more complex properties, configuring a
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S. Bandini, A. Bonomi, F. Sartori
new guitar not only in terms of features derived from simple aggregation
or specification of parts (i.e. Part Of and IS A relations), but also of complex characteristics deriving from their combination to obtain given results
(e.g. The guitar timbre must be clear).
At the end of the functional ontology development, we’ll be able to plan
the second part of the project that aims at representing procedural knowledge concerning the different steps of the manufacturing process starting
from the CAD model of the body. This project phase will consist in the integration of the guitar functional model represented by ontology with constraints coming from NOAH experts in aluminum processing. The expected result of this project step is the integration of NavEditOW with
tools for the management of procedural knowledge, like e.g. SA*-Nets [7]
or Influence Nets [18].
Finally, we are now planning the second part of the project that aims at
representing procedural knowledge concerning the different steps of the
manufacturing process starting from the CAD model of the body. This project phase will consist in the integration of the guitar functional model represented by ontology with constraints coming from NOAH experts in
aluminum processing. The expected result of this project step is the
integration of NavEditOW with tools for the management of procedural
knowledge, like e.g. SA*-Nets [7] or Influence Nets [18].
Acknowledgements
Authors wish to thank NOAH experts for their support in writing the paper, and in particular Gianni Melis, whose competencies and expertise we
have tried to model in the current version of the system. Special thanks to
Andrea Fulciniti for his work.
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