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Controlling and Assisting Activities in Social Virtual Worlds
1. Introduction
Since its beginning, web technology has advanced from a text-based to a visual-based
interaction. This evolution has been facilitated by both high speed internet connections and
PC's graphical power. Virtual world (VW) technology began as standalone applications
(e.g.. virtual simulations) but soon evolved into web-based applications. Nowadays, home
users for entertainment and wide-spread enterprises or institutions for business can exploit
virtual worlds to develop remote activities between friends, employees, clients, teachers or
students (Sherman, 2002). Then, virtual worlds have clear applications in e-governance, elearning
and e-commerce, and therefore it is mandatory to study mechanisms ensuring the
assistance and the control of activities taking place in these applications.
We focus on social virtual worlds populated by participants that act in order to achieve
common and individual goals (Bartle, 2003). Due to the type of activities taking place in a
Social Virtual World (SVW), the virtual environment should be prepared to be a dynamic
space where participants are informed about activities' evolution and where norms are used
to organize participants' actions, to define actions' consequences and to prevent undesired
participants behaviours. We rely on electronic institutions (Esteva, 2003) to set up
participants' valid interactions and on virtual objects, named intelligent objects, populating
the virtual world, to enforce norms and to give assistance to participants (Rodriguez, 2008).
This work exploits the Virtual Institution (VI) concept which is a combination of both
Multiagent and virtual world technologies (Bogdanovych, 2007).
We have designed a general framework of object behaviour control tied with an IA based
external module and prepared to be exploited by several virtual world platforms. This is
done creating a specific module to capture participant interactions on objects populating the
virtual world and connecting this module with an external and generic one in charge of
deciding what should be the virtual object action. Decision depends on an organizationbased
multiagent system (MAS) which, as said before, establishes the valid interactions
participants may have and the consequences of those interactions. Our main objectives are:
•Establish participants' roles, activities and norms by means of a multiagent system
named electronic institution. Participants can be both software agents and humans.
Controlling and Assisting Activities in Social Virtual Worlds
•Use of intelligent virtual objects with an external module named iObjectmanager i)
to inform participants about activities evolution and ii) to decide whether
participants comply established norms.
•Design an object behaviour control scheme applicable to different VW (Virtual
World) platforms.
•Exploit the virtual nature of the spaces, and the objects populating these spaces,
allowing to represent things impossible for their real world counterparts.
The dynamic feature of current VW platforms only rely on users who are free to
dynamically change aspects of the virtual world by means of built-in tools and scripting
features. Our proposal is to extend the ability of a VW to dynamically change itself and
exploit the virtualness of the space supporting the presentation of information, which would
be impossible to do in the real world, and so provide a better support to participants on
their activities.
This chapter is structured as follows. Section 2 presents related work in areas related with
norms enforcement in virtual worlds and multiagent systems combined with virtual
environments. Section 3 describes how our system models activities taking place in
normative virtual worlds and uses intelligent objects to guide and control the user during
the activities. Section 4 presents the developed intelligent objects framework and finally
section 5 presents conclusions and future work.
2. Norms in web based communities
Most of well-known virtual communities -such as Second Life, Active Worlds, Entropia and
others- require participants to agree to the company's terms of service in the signing up
process (Linden, 2008). Participants should understand the terms and conditions to which
they are agreeing as a member of that community. Most people don't read or are otherwise
immune due to the lack of real consequences. There are some types of incorrect behaviours
that we think can be addressed programatically, that is contemplated in the design of the
VW platform and ensured at deployment time.
We propose to use intelligent objects (iObjects) as elements helping users to comply norms
and if it is necessary to prevent forbidden actions. For example, to block entry to people who
is less than 18 years old in a special virtual room. WonderDAC is an extension module
developed for Wonderland that allows to show or hide parts of a VW depending on the user
and group profile (Wright and Madey, 2008). In contrast to WonderDAC, developed to
control discretionary access basing on users and group permissions, our approach is more
general allowing, for example, the control of access to spaces based on the historic of user
activities. For example, a norm establishes that a participant can not enter to the projection
room unless he has bought a ticket for that room and session.
Part of our inspiration for a general interaction approach for objects populating a social
virtual world comes from the smart objects proposal (Kallmann et al., 2000) (Abaci et al,
2005) and the posterior work done by Jorinssen (Jorissen et al., 2004) (Jorissen et al., 2005).
Nevertheless, our approach is different to those because they worked with their own virtual
environments named ACE (Agent Common Environment) and ALVIC (Architecture for
Large-Scale Virtual Interactive communities), respectively. In this way, their object
interaction approach is general in the sense it is independent of the final application but can
14 Web Intelligence and Intelligent Agents
not get out of their concrete virtual platform (they have their own scripting language and
engine). Our interaction framework for control and assist activities in SVW has been
designed to be applied to different VW platforms such as Wonderland and Second Life. In
this way, rendering and event capture continue being controlled in the concrete VW
platform but the behaviour decision is managed in an external and generic manager
connected with an AI based module, i.e. Electronic Institution.
Virtual worlds can be seen as singular information spaces where the virtual nature of the 3D
space (e.g.. floor) and the furniture (e.g.. noticeboard) can be exploited in a special manner
not possible for their real counterparts. For example, in the real world it is not possible to
dynamically change tiles colour in a floor to represent an agree/disagree position of
participants in a discussion. This has been done in a recent work (Harry &Donath, 2008).
We aim to incorporate an added value to virtual objects allowing to give valuable
information to participants. As an example in section 4.1, a door is visualized either green or
red depending on the user trying to pass through. Accessibility issues can also be addressed
in these information spaces, for example a noticeboard object adapts letter size depending
either on user profile and on the distance between the user and the panel. Exploiting these
native properties of virtual objects, we create rich and expressive social spaces.
We extend the dynamic conception of current VW platforms in which users are free to
dynamically change aspects of the virtual world by means of built-in tools and scripting
behaviours (Friedman et al., 2007) (Sun, 2008). Part of the unexplored feature of virtual
spaces is their ability to be adapted in architectural terms. Our proposal is to extend the
ability of a VW to dynamically change itself and exploit the virtualness of the space
supporting the presentation of information, which would be impossible to do in the real
world, and so provide a better support to participants on their activities.
Combining multiagent systems and virtual environments
A system that incorporated intelligent agents within virtual environments was mVITAL
(multi-agent VITAL) which allowed the definition of agent societies so that intelligent
agents could communicate through simple speech acts, co-operate and help each other to
achieve goals (Vosinakis et al., 1999) (Anastassakis et al. 2001a) (Anastassakis et al. 2001b) .
The mVITAL viewer allowed human supervisors to observe the activity inside the
environment. We propose to allow the user not only to supervise but to control his avatar
and communicate with a regulated multi-agent system in order to test whether his actions
are allowed. We have used the so-called iObjects in order to provide facilities for avatarobject
interaction and the visualization of the social virtual world execution context. A detail
description of iObjects integration at MAS level by means of an Interaction Language can be
found in (Rodriguez et al. 2007).
Several researches integrated BDI (Belief, Desire and Intention) agents within virtual worlds.
Torres et al. developed an interface that allowed a BDI-based agent reasoning system to be
used for guiding the behaviour of articulated characters in a virtual environment (Torres et
al., 2003). ACE (Agent Common Environment) was designed for virtual human agent
simulations. It provided pre-built commands to perceive and actuate meanwhile the
reasoning processing is defined by means of a collection of external modules (i.e. python
scripts)(Kallmann et al, 1998), (Kallmann et al, 2000). Virtual agents were used to enhance
Customer Relationship Management (CRM).eGain's virtual assistants interact in plain
English over the Web with online users (Osterfelt, 2001). They combined 3D graphical
Controlling and Assisting Activities in Social Virtual Worlds 15
representations and artificial intelligence to assist customers to locate information or place
orders. Our system provides assistance to the participant also by means of 3D graphical
representations (i.e. iObjects). An iObject allows the user to be aware of current execution
state (e.g.. data visualized on an intelligent noticeboard), enforcing norms (e.g. let to pass
through a door depending on user previous activities) and adapting object's features
depending on user profile (e.g.. adapts the font's size of a noticeboard depending on user's
visual capacity).
Guyot and Honiden's approach merged multiagent systems and role-playing games
(MAS/RPG) (Guyot, 2006). They compared agent-based participatory simulations and the
MAS/RPG approach and explained the advantages of their approach: ''actions and
interactions can be registered and used for learning purposes, the gap between the agent
model and the participants can be decreased and the user interface with an assistant agent
may improve the understanding of the model by the participants''. Our system, exploiting
iObjects in the context of social virtual worlds, aims to work along those advantages too.
Another research conceives the organisation infrastructure of a multiagent system in terms
of agents and artifacts (Kitio et al.. 2007). They distinguish between organizational artifacts,
which provide organization’s functional aspects, and organizational agents, which provide
decision aspects of organizations management. Artifacts and iObjects, although both arise
with a similar objective, that is, to model “entities” used to develop activities in the
institutions, they are situated in different levels of abstraction. Artifacts facilitate agent
activities at a organizational MAS level and iObjects facilitate user interactions at 3D world
level.