VIRTUAL MUSEUM – AN IMPLEMENTATION OF A
MULTIMEDIA OBJECT-ORIENTED DATABASE
Rodrigo Filev Maia, Jorge Rady Almeida Junior
Escola Politécnica – Universidade de São Paulo (EPUSP)
Av. Prof. Luciano Gualberto, 158. trav. 3 cep:05508-900 – São Paulo- SP - Brazil
Keywords: Virtual museum, object-oriented database, multimedia content.
Abstract: This paper describes the main characteristics involved in th
e process of using multimedia content in the
Internet sites and it presents a proposal for an implementation of an object-oriented database, in order to
assist the multimedia data exigency in a dynamic website. It is described an implementation of the proposed
architecture, consisting of a virtual museum made for the Contemporary Art Museum of the USP, called
Virtual MAC, which was elected as the 3
rd
best virtual museum of the world by INFOLAC Web 2005
(UNESCO) . The main objective of Virtual MAC is to create a virtual collection of works at art and make it
available on Internet. Our analysis shows that it is more appropriate to use the Object Oriented paradigm
instead of Relational Modelling due to the nature of the multimedia data and the structure of the dynamic
web site used for the Virtual MAC.
1 INTRODUCTION
Nowadays there are a great variety of multimedia
items, which can be inserted in a database, such as
images, audio and video files. It must also be
considered that this type of data has several
parameters which should be take into consideration
whatever may the system be, and must be stored in
the database, such as the quality of a video image or
the taxes of audio samples. The kinds of objects,
which have some special characteristics, must be
considered during the database design. The new
applications on Internet have massive use of
multimedia data, such as audio, video and several
types of animation files. Another trend on Internet is
the building of dynamic sites in order to provide a
fast way to update or change information for the
users. A difficult task that appears in this scenario is
some limitations in the relational databases that
could be used to support dynamic sites. The main
reason of the difficulties is the representation of
complex data in the relational database, such is the
multimedia data. The limitation presented in storing
and recovering complex data may increase the
complexity of the site application (Rashid, 2001). In
the case of a Virtual Museum, there is a huge
amount of multimedia data, such as videos, pictures
and animation files. It is turn not properly the use of
relational database to support the dynamic site, such
as Virtual MAC, and the use of an oriented-object
database becomes the more appropriate approach to
address a solution for the virtual museum. In order
to present the structure and considerations among
the Virtual MAC, following sections composes this
paper. The section 2 describes the relation between
an object-oriented database and the structure of web
documents, such as web pages, and it is shown why
the use of object-oriented database if a quite better
option to build the Virtual MAC, instead of to use a
relation database. The section 3 and 4 describes the
Virtual MAC and the structure of object-oriented
database, and the section 5 brings some final
remarks about this work.
2 MULTIMEDIA DATA AND
OBJECT-ORIENTED
DATABASES
Multimedia contents are presenting more importance
through time, since they represent new types of
communication through the Internet. We can say
that these multimedia data constitutes a new kind of
communication, allowing the implementation of new
communication ways. (Hacid, Declair,
Kouloumdjian, 2000).
102
Filev Maia R. and Rady Almeida Junior J. (2006).
VIRTUAL MUSEUM AN IMPLEMENTATION OF A MULTIMEDIA OBJECT-ORIENTED DATABASE.
In Proceedings of the First International Conference on Software and Data Technologies, pages 102-107
Copyright
c
SciTePress
The multimedia data is defined, for the purposes
of this paper, as the content composed by text,
audio, video and graphics or any combination of
them. The multimedia data have some peculiar
characteristics like larger complexity (difficulty to
represent them in the relational model - e.g. an
electronic circuit), multi-valued and complex
structure fields (e.g. an industry plant). This leads to
the use of object-oriented databases that can
implement, in a more efficient way, such aspects,
when compared with Relational Databases. (Elmasri,
Navathe, 2003). It means that the database schemas
are designed to deal specifics data types and
application scenarios, and they do not consider a
hybrid type of data, such as multimedia. (Woelk,
1986).
The difficulty to represent these data types in the
Relational Database is the possible combination of
the elements and their representation as valid
Internet documents (Ishaq 1999). Nowadays, a web
site is composed by more than one of these types of
pages. When a dynamic web site must be built, it is
complex to represent all these page possibilities in a
relational database (Wen, et al. 2003).
Taking into consideration the implementation
methods of such complex system, it is more
appropriate to make the implementation directly in
an object-oriented database management system,
avoiding the problem of impedance mismatch. The
option of storing complex information in an Object-
Oriented Database has a clear advantage over
Relational Databases: the complex information of an
object could be better represented and its data may
be easier accessed by the user application through an
object-oriented database. The object could also be
composed by other objects, which could facilitate
the representation of more complex data. (Yu,
Meng, 1994), (Tepfenhart, Cusick, 1997). All
methods that work with the object do not need to be
implemented in the application that builds pages.
Instead of that, the application only use what it is
defined inside the database, which simplifies and
guarantees that all pages will work with the object at
the same way. This encapsulation is useful in order
to permit that any modification in one object of the
database does not damage or interfere in any other
object functionality. The approach proposed for this
work is closer than Service Oriented Architecture
(SOA) approach (MacKenzie, et. al. 2006), or even
the usual Internet programming patterns, such MVC
(Modelling, View and Control)
3 AN IMPLEMENTATION OF AN
OBJECT-ORIENTED
MULTIMEDIA DATABASE
The “Museu de Arte Contemporânea da USP”
(MAC USP) (Museum of
Contemporaneous Art of
University of São Paulo) has an outstanding
collection of around 8,000 pieces of art, including
paintings, prints, drawings, photographs, engravings,
sculptures and conceptual works, constituting a great
cultural heritage with national and international
influences. The main idea of Virtual MAC is to
associate the information technology with art,
making available all the collection that belongs to
MAC. Considering that one of the purposes of the
site is to divulge the MAC around the world, the
information in the site is displayed in three different
languages (Portuguese, Spanish and English).
The system database should contain all
significant information for each work of art. Some of
the most important kinds of media are high quality
images, besides files of video and audio. The basic
reason for the need of high quality multimedia files
is that users may need to have access to images that
allow the observation of the work’s details.
Considering the three-dimensional works, it is also
desirable to have the possibility to visualize them at
the same perspective of a real visitation.
3.1 A Proposal for an
Object-Oriented Multimedia
Database
In the Virtual MAC all pages must be dynamic
because researches from museum can need to
modify, add or even delete some information or
picture about any work of art at any time. Each one
of the work of art stored in the database has several
features related to itself and also with its
presentation in the website. One important target of
this system is presenting the world of art for
common people, and at same time provides useful
information for art specialists. The Virtual MAC
must also provide the better experience for the user
as possible. For instance, three types of images and
two types of text compose the work of art. There is
one image to be shown as an icon, one for users that
are connected on the Internet by a dial system; and
there are another rich image for ADSL, and another
for the Internet2 users. The last type of image could
have more than 10Mbytes each one, and permits to
observe minimal details of an work of art, such as
the author’s signature. The Virtual MAC has the
following types of multimedia information and tools
VIRTUAL MUSEUM – AN IMPLEMENTATION OF A MULTIMEDIA OBJECT-ORIENTED DATABASE
103
on the Internet, which must be supported by object
oriented database:
Information about work of art: texts with useful
information such as work of art description,
historical information, author’s life, etc;
Work of art images: several of them were
digitalized and it is reproduced in two resolutions.
One it is for dialup and ADSL Internet
connections, and the other is for Internet 2
connections (very high quality image);
Animations about sculptures: the three-
dimensional work of art can be view by the web
site visitor at the same angles that they could see
in the museum;
Virtual tours and expositions: expositions can be
built and the virtual visitor can “walk inside” the
museum. He can see the work of art and select
one of them to receive more detailed information;
Videos and audios about art and the museum:
videos and audios have three types of quality: one
for dialup connections (until 56kbps), one for
ADSL users and other to Internet 2 users (high
video and audio quality).
The table 1 presents the main requirements of
the Virtual MAC, in order to support all information
types and pages used in the web site of virtual
museum.
3.2 Involved Technologies
In order to build such complex Internet system
following the proposed requirements, it was built a
web site based on dynamic pages, which was
developed in Active Server Pages (ASP)
1
. The
choice of this development platform was based on
the Application Program Interfaces available for
database manufacturer. However, the same kind of
system could be developed in any other development
platform, such Java (using Struts, Java Server Faces
or any other technologies). As it was used ASP the
application server is the Internet Information Server.
It was also used a streaming server in order to
provide some videos.
The Virtual Mac database was Caché 5.0 and
one of the main reasons to choose this tool was its
availability and its development interface and some
API for Microsoft’s environment.
4 DATABASE ARCHITECTURE
The database used to implement the Virtual MAC
was an object-oriented database. There were
designed two distinct databases, the first one for the
virtual collection and the second one for the
dynamic site. In a dynamic site there are no pages
written in HTML and their contents are stored in a
database. Another characteristic is that there are no
predefined pages in a dynamic site. The HTML code
for each page is generated when requested by each
user, through their access to the site page.
One of the main advantages of this kind of
practice is to facilitate the publication of updates,
1
ASP – Microsoft Corporation
Table 1: Main requirements of Virtual MAC.
Object type Information Requirements Internet Requirements
Work of
art
- Name of the picture or sculpture;
- Author’s name;
- Artistic school;
- Year of the work of art production;
- Short description of the work of
art;
- Complete description of the work
of art;
- Images from the work of art (in
different resolutions);
- What image of the work of art must be
presented into website (related to the user’s
bandwidth);
- Quality and size of the image;
- The file names containing some animation
or image of the work of art;
Audio - File size;
- Description about audio content.
-The audio quality that would be used in the
website in each bandwidth;
- Audio quality and format;
- Audio location (in the hard disk);
Video - File size;
- Description about video content
-The audio quality that would be used in the
website in each bandwidth;
-Video quality and format;
-Video location (in the hard disk);
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which may improve the usability of the site, since
anyone may publish contents in the website
independently of his technical skills in web
technologies. In order to support all functionalities
of the website, it was employed an Object-Oriented
database, which demonstrated to be very suitable,
because of the complex nature of the data stored.
(Barbosa, 1992). The Figure 1 shows an example of
a work of art available at Virtual MAC The site
address is http://www.macvirtual.usp.br.
Figure 1: Example of a work of art in the Virtual MAC
collection.
4.1 Virtual MAC Database for
Work of Art
The main attributes of each work of art stored in the
object-oriented database are name, date of creation,
catalogue number, dimensions and others, justifying
the creation of an object. More than one artist might
have done one work and each artist may be the
author of one or many works. Each author has
particular characteristics, justifying another object.
This structure was applied in other components of
Virtual MAC, and results in a simplified class
diagram shown in figure 2.
The main class, which it is the “core” of the
database is called Artwork, and it is responsible by
the control of all information related to pictures,
sculptures and any other type of work of art. This
class also has methods that manipulate its
parameters, such as storing information from an
object, or modifying some parameter.
The class Artwork has some inherent classes,
which works as parameters of the class. One of these
classes is called Object_360, and it controls the
sculptures animation. It makes possible to the
Internet users round the work of art and observe
several details. The same happens with Description
class when all descriptions have the same
characteristics for any class, and the edition controls
are the same for any component of the dynamic site.
The class Picture manages all characteristics
belonging to all images of the work of art. This class
controls the quality of the image, files size and
name, and also controls what image can be used in
each type of connection (dialup, broadband or
Internet 2).
Artwork
Collection
Technic
Artistic Tendency
Picture
Artistic School
Object_360
Exposition
Description Author
1
1..*
1
1..*
1..*
1
1
1
1..*
1..*
1
1
1
1..3
1
1
11
1
0..*
Figure 2: Class Diagram of Object Oriented Database
from Virtual MAC.
The database does not copy the entire object
inside another one, when an object has other object
as its parameter. Instead, the object stores references
controlled by the Object-Oriented Database
Manager, which build the relationship between
objects. A clear advantage of this is that one object
can be used by several other objects, as it happens
with Author class. This feature of sharing objects
increase the importance of the object controls its
own parameters, in order to avoid that one object
changes some information and damage other one.
4.2 Virtual MAC Database for
Dynamic Site
The second database implemented for Virtual MAC
supports the publisher system. It maintains all data
necessary for dynamic pages generation. The
database follows the class diagram shown in figure
3.This database was implemented using the same
database management system of the work of art
database, and its main function is to store all
information from website not related to the work of
art, such as information about courses, the museum
history and museum partnerships. SiteArea is one of
the database classes containing the website areas
(expositions, virtual tour, etc.). The control data of
each specific item is stored in PageContent.
VIRTUAL MUSEUM – AN IMPLEMENTATION OF A MULTIMEDIA OBJECT-ORIENTED DATABASE
105
The content is controlled by the object
Description, which is common to all objects, making
uniform all website contents for maintenance
purposes. In the class Event, any MAC event is
registered and controlled, and the class Agenda, is
used to date activities like expositions, workshops
and laboratories, for example. The class
AbstractPageContent stores all parameters form
class PageContent. This last one has all methods and
inherits the properties of AbstractPageContent. The
same happens with Event and AbstractEvent class,
and all inherits mechanisms are provided by the
database manager system. (DEV_APP 2002),
(Cache_Ref 2002), (Cache_Tool 2002).
4.3 The Virtual MAC Access
According to statistics collected from the Virtual
MAC website, there was a huge increase of access
since the proposed system was available. The figure
4 indicates the number of access in 2002 in which
Virtual MAC was online from October to December
and from 2003 until March 2006. In 2002 MAC had
less than 7000 access during these three months,
what it is about 2190 access per month. In 2003, the
first complete year of Virtual MAC, the number of
access was 105.610, an increase of 401,8% (based in
access per month). It may be observed that the
number of accesses continuously increases during
the years. In 2005 the number of access was
approximately 29.572 access per month, and in 2006
this number is closer than 83.437 access per month.
It reflects the robustness of the system, mainly the
database, which support and store all data consulted
by visitors, and the performance is quite appropriate,
since it has no complain about usage or lack of
resources during interaction between users and the
application.
Update
Project
Description
AbstractPageContent
Museum Staff
PageContent
SiteArea
AbstractEvent
Exposition
Course Museum Agenda
Event
1
0..*
1
1
1
*
1
1
1
1
1
*
1
1
1
1
1
1
0..*
1
Figure 3: Class Diagram from Dynamic site.
Certainly, this success (in terms of increase in
accesses) is not the directly result of the technology
used in the Virtual Mac development only, but the
cause of the success is also the page design and the
content of the museum. However, the technology
presented in this work is one of the key aspects of
the Virtual Mac success, since all information is
based on the database and the developed software.
All website tools provide great level of
interactivity and works with rich media, which
implies in quite new and robust software as well as a
system whom permits fast data recover and access.
One of the key for Virtual Mac success is the
combination of technology and rich and interesting
media, which guarantee a new kind of experience for
the Internet user.
5 CONCLUDING REMARKS AND
FUTURE WORK
The object-oriented database demonstrates to be an
interesting and powerful solution to manage
multimedia content. This type of database permits to
create more complex data structures, which can be
used directly in the application code, since it is
based on the database API. As this technique
simplifies the application code implementation, this
process was fast, once all methods that manipulate
the objects were inside the database. All pages,
independent of its location, have access to the same
classes and methods, which facilitates the use of the
information in the whole site.
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The actual database architecture is appropriate for
the actual requirements. Although the efficiency of
this architecture, it is a desire to integrate new tools
and games in the Virtual MAC website. One tool is
based in VRML (Virtual Reality Modelling
Language), which allows that any user from Internet
builds its exposition and opens it for other users.
There is a prototype of this environment, but it is not
integrated with the object-oriented database yet.
Other tools such as puzzles can be obtained from
work of art pictures and some programming in order
to create an algorithm to make the picture in small
pieces and to control the interaction with users. This
type of tool can also be developed based in the
object-oriented databases, since the pictures stored
in the system could be used in order to generate the
puzzle.
ACKNOWLEDGEMENTS
The authors thank the support of Santander Banespa,
MAC - Museu de Arte Contemporanea
(Contemporary Art Museum of the USP) and FUSP
(Fundação da Universidade de São Paulo), in the
development of this work.
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Number of Ac cess
6572
105610
150783
354867
250312
0
50000
100000
150000
200000
250000
300000
350000
400000
2002 2003 2004 2005 2006
Figure 4: Virtual Mac – Number of accesses.
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