Autonomous Agents in Collaborative Virtual Environments

8/3/2019 Autonomous Agents in Collaborative Virtual Environments

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Autonomous Agents in Collaborative Virtual Environments

Dr. Stefan Noll

Christian Paul

Ralph Peters

Norbert Schiffner

Fraunhofer-Institute for Computer Graphics

Rundeturmstrae 6

D-64283 Darmstadt, Germany

+49 6151 155 209

{noll, paul, peters, schiffne }@igd.fhg.de

ABSTRACT

Our world is now entering an age where the current

understanding of telecommunications and graphics

computing will be constantly challenged. The universal

advancement of graphics technology, new business

models, and the continuing upgrade of global

infrastructure are transforming the solitary, platform-

centric 3D computing model. With the availability of

global information highways intercontinental collaboration

using 3D graphics will become part of our daily work

routine.

The research efforts have been concentrated on

determining how the distributed workplace can be

transformed into a shared virtual environment. Interaction

among people and processes in this virtual world has to be

provided and improved. To enhance the usability and

functionality of our collaborative virtual environment we

integrated software agents into it. These agents support the

user as well as the designer and the interaction with

objects in the virtual world. In this paper, we describe the

basic needs for combining agents and virtual worlds as

well as techniques to enhance VR environments.

Keywords

Collaborative virtual workspace, cooperation, software

agents, integration, usability, architecture.

1. INTRODUCTION

The combination of 3D graphics, spatial audio, object

interaction, and haptic feedback in a distributed virtualenvironment constitute a multidimensional form of

telecommunication. This framework addresses the three

main perception senses of human beings simultaneously.

These advanced forms of telecommunication make it

possible to transform workplaces into collaborative virtual

workspaces (CVW). Scenarios can be tailored to the

particular needs of an application or user. Possible

applications range from simple distributed multimedia

visualizations of scientific data in standard 3D data

formats to distributed VR environments for teleconferences

and simulators [1], which demand advanced computer

technology.

In this paper, we introduce the use of agents in

combination with virtual realities as a future

communication system. By doing so, two major fields of

Computer Science are tied together: agents, which stem

from the field of Artificial Intelligence (AI), and 3D-VR

systems as part of Computer Graphics. The main goal is to

enhance usability and realism of virtual environments by

combining 3D objects with intelligent agents, and to

explore new aspects evolving from this combination.

As a basis for our work introduced here, we use our

collaborative virtual workspace. Using this framework we

built the Virtual Emergency Task Force (VETAF) and

Virtual Showroom scenarios [4].

Concepts of software agents, their usability and

employment in virtual environments, exemplary

implementations of agents, our scenarios, and relateddevelopments are explained in this article.

In a virtual reality, objects and avatars are connected to

agents, which reflect a behavior to other agents and users.

Agents act autonomously and improve interaction between

objects. The following short description of the applied

agent technology gives an introduction into this topic.

2. SOFTWARE AGENTS

Software agents are most relevant and applicable for the

use in real-world domains. Their intelligent behavior

enables them to automate and delegate cognitive tasks that

were not feasible for machines in the past. Agents support

each user individually during a session. They act as arepresentative of their 'employer' in the task they are

assigned to.

Several dimensions can classify agent technology: their

mobility, whether they are deliberative or reactive, their

appearance, and their roles. Three major attributes may

describe the behavior of software agents in general (for a

more complete definition of the term agent please refer to

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and [9]):

Autonomy: The ability to take initiative on what theagent believes is in the users interest. It fulfills its tasks


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based on internal states, rules, and goals, and does not

need any guidance by a human.

Cooperation: The agent is able to engage in complexcommunication with other agents to obtain information

or help of others. The agent society cooperates to

accomplish their owners goals.

Learning: In order to be smart, agents have to adapt totheir environment. They need to learn how to react or

interact with the system, users, and other agents.

One major issue of agent technology is cooperation

between agents. Independent, heterogeneous agents

therefore need a flexible possibility to communicate with

each other in order to adapt to their environment. This

communication facility has to fulfill two major tasks: on

the one hand, various kinds of information must be

transported reliably, on the other hand, the content of

every message has to be understandable by every agent.

However, the agent does not have to be able to interpret

the object included in the message. Agent Communication

Languages (ACL) solve these problems by using

communication objects with a specified structure. ACL

messages are well defined and can be processed without

necessarily knowing about the embedded object of a

message (content). The most common ACL is the

Knowledge Query and Manipulation Language (KQML).

KQML is an agent communication language developed by

the ARPA supported Knowledge Sharing Effort [2]. It is a

message format and message handling protocol to support

runtime knowledge sharing among agents. It provides high

level access to information and serves for low level

communication tasks such as automatic error checking.

3. AVATARS & AGENTS IN WORKSPACES

The main issue addressed by virtual environments refers to

social and workspace awareness in CVWs. Avatars address

this problem by representing users in virtual environments.

Agents can enhance usability, convenience, and realism

when the virtual human is present in the collaborative

virtual workspace.

3.1. Avatars in CVWs

Avatars are controversial creatures on the cutting edge of

user interface designs. They provide new ways for peopleto interact with their computers and with other users on a

network. The driving force behind avatars is the ongoing

search for an interface that's easier and more comfortable

to use, especially for the millions of people who are non-

computer experts. The earliest computer users were

engineers and programmers who were fairly comfortable

with command-line prompts. Today, most users are

professionals who are fairly comfortable with graphical

desktops. But a metaphor based on files and folders means

nothing to a five-year-old, and the abstractions of menus

and icons are difficult for even some adults to grasp.

Avatars won't necessarily replace menus, icons, and other

elements of GUI computing. Instead, they'll play the role

of helpful assistants or guides. Proponents think avatars

are tailor-made for the growing virtual communities of on-

line services and networks.

Avatars are an important metaphor in CVWs: users can

determine whom they are sharing the information with andin which particular object the other person is interested.

Positions can express if users are following the discussion

and whether they are looking at the same object. They

express if users want to talk to somebody or if they are

moving tirelessly and nervously around. Appearances of

avatars show the status of participants in the world: they

can express a user's rank in a group, show if users are

present at work as well as show the individual taste of a

user.

Realism in participant representation involves two

elements: believable appearance and the capability of

movement.

This becomes ever more important in a CVW, since the

participants' positions are used for communication. As an

example: The distance between avatars controls the

volume of the participants' audio. The participants local

environments store the whole scene description and use

their own avatars to move around the scene. Rendering

takes place from their own viewpoints. This avatar concept

in CVW has crucial functions in multi-user virtual

environments:

Perception (see if anyone is around)

Localization (see where the other person is) Identification (recognize the other person)

Visitation of other person's interest focus (see wherethe persons attention is directed to)

Using abstract virtual figures for avatar representation

(Figure 1) fulfils these functions. Our avatar uses a live

video stream and a business card identifying the user it

represents. The video screen indicates the direction in

which the user is currently looking. Each user is assigned

a unique colour; ears and feet of the avatar as well as the

selection pointer are all in this colour. To point to an

interesting position or perform an action the user can use a

distributed pointer, located on top of the avatar.

In a collaborative virtual environment, the system has to

know which objects are in a scene, how to represent them,

and where they move in case they are not static. Any

communication between objects, no matter if they are

under control of a user or the underlying program, is

difficult to predict and also difficult to implement as they

should fit in different scenarios. One possibility to solve

the problem is the use of agents. Each object or object

group in the virtual collaborative environment is connected

with its agent (Figure 2). Agents act according to their


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functionality and are able to enhance interaction between

objects and the virtual environment.

Figure 1: Avatar

Avatars, the graphical representations of participants, are

also objects. Therefore, agents can act on a higher

abstraction level, like human assistants. This includes

repetitive tasks (for example finding a way through the

scenario and locating a room within it), remembering

certain facts, which the user forgot, and recapitulating

complex sequences in an intelligent way (who is in a room

and which action is she or he performing at the moment).

Intelligent agents can learn and even make suggestions to

the user.

3.2. Agent-Object Pairs in CVWs

While evaluating the integration of agents intocollaborative virtual workspaces, several fundamental

functions and tasks have been identified. The central idea

is building Agent-Object pairs: Every graphical object in

the virtual environment that represents a certain universal

service owns an underlying agent. The following actions

are regarded as essential functions for these pairs:

Creation: When a new object is brought into the scene,the agent creates the graphical representation and

distributes the necessary data to every participant of the

environment.

Administration: Every action and event concerningthe object is dispatched and then, given certain premises,

distributed or reacted on by the agent.

Modification: The user has the possibility to changethe graphical representation of objects (and avatars) in

form and color. Every object controls these attributesitself. The agent is responsible to keep modifications

consistent. All new appearances are broadcasted via the

multicast network.

Control: The object itself has no information about itsinner state except of appearance; the agent has full

control over its functionality and position in the

environment being responsible for moving around,

contacting other agents or users, perceiving the

environment, and gathering useful information (in the

sense of fulfilling a certain task).

Erasure: Similar to creation, the agent deletes itsgraphical representations in all environments and the

underlying functionality.

While developing agents for multi-user environments, the

following problems were encountered and had to be coped

with depending on the particular type of application and

agent:

One or many underlying agents for the objects: Theprogrammer has to evaluate if it is applicable to use one

agent for all object instances, or if it is more useful to

provide an underlying agent for every occurrence of the

graphical representation. For example, guides in the

environment (see below) should have their ownunderlying agent but share one information agent. This

agent is responsible to provide information about the

environment because it is useful to have one database

about all rooms and participants taking part in the

scenario.

Handling objects: Cloning and multiplication ofobjects in virtual environments can lead to

inconsistencies. The underlying agents have to keep

track of these user actions and should be able to replicate

themselves (in case every object is controlled by its own

agent), or adapt to the new instance of the generated

graphical object and provide the functionality controllingit.

Mobile agents: If the graphical object is attached to amobile agent, its functionality is accessible by one user at

a time. Scheduling of many requests of using the object

has to be controlled and dealt with by the agent. For

example, if you implement the guide agents as mobile

agents, you might have to contact a receptionist and ask

for assistance. The receptionist will contact the mobile

guide agents and request information about availability.

(For more information about mobile agents see [9].)


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The possibilities of using agent technology to assist the

user, populate the environment, and add functionality to

virtual environments are numerous. In the following, we

describe the integration of agents into virtual environments

and explain the use of guides in the scenario.

4. INTEGRATING AGENTS INTO CVWsIn the previous chapters we described software agents in

general and the theoretical conditions for the integration of

agents into VCWs. This chapter explains how we put our

thoughts into practice.

Figure 2: CVW and Agent Setup

Figure 2 shows the general setup, which is split into two

parts: the multicast net and the agent net. The multicast

net (solid ring) consists of a multicast backbone (MBone,

which is explained in the 'Application' Chapter). It

connects the CVWs and is the basis for transmitting

continuous audio and video feeds as well as all changes

that occur in the virtual environments (i.e. who is present,

how does the avatar look like, what is the current position

of every participant). The agent net (striped lines)

interconnects all agents by using the communication

facilities of ASAP. This partition into two independent

nets results from the different needs for communication

and scalability uses. While agents rely on a secure

submission of their messages, video and audio feeds do not

have such requirements; they need high-speed connections

to allow real-time transmissions. Agents come to full effect

when they form agent societies, consisting of a largenumber of agents acting in and therefore supporting a

comparably small number of virtual environments.

So-called CVWAgents link the two subnets together. They

accept messages from either side and enable the agents to

control objects in the environments, as well as transferring

user inputs from the CVWs to the corresponding agents.

The CVWAgents have a twofold functionality: on the one

side, they are participants of the workspace by sending and

receiving multicast messages. On the other, they are agents

being able to understand KQML messages. Their main

task is to listen on both nets, filter all information

necessary for the other side, and translating these

messages appropriately. For example, when a position

message on the multicast net is recognized by the

CVWAgent to be relevant for an agent, it translates this

message to KQML and sends it to the relevant agent using

the agent network. Figure 3 displays the central position ofthe CVWAgent.

Figure 3: The Role of the CVWAgent

Another example is the interaction between a user and the

agent society: Using the avatar's graphical user interface

(GUI), the participant issues a message requesting a

special service. Assuming that a button was pressed, the

CVW core will issue a message containing this event on

the multicast net. The CVWAgent converts this message to

KQML and sends it to the appropriate agent using ASAP

and its agent network (for more information on ASAP,

please refer to Chapter 5.1.) This initiates the execution of

the desired service.

An Example: The GuideAgent

To show the usability of agents in virtual environments,we built a set of agents: DoorAgents restrict access to

rooms and seek for identification or payment, and

UserAgents provide information about their employers,

handle access codes and payments whenever they are

entitled to [7]. This chapter considers the GuideAgent. Its

main task is to walk around the environment and provide

information about objects, participants and the

environment.

The guide fulfills all properties of the above mentioned

agent-object pair: it has its own distinct representation by

the use of a special avatar and an underlying agent to

control this graphical representation. The GuideAgentdoes not only send out position messages to move its

avatar around the scenario but also manages an area of

interest. If another participant appears within this area, the

GuideAgent identifies him and offers help. If the user

refuses this offer, the guide will move on. If help is

needed, the guide suggests many different services:

Navigation aid: Especially novices usually havedifficulties in using the different moving modes (i.e.

walk and fly) to move their avatar. The guide can

therefore provide a lesson of how to navigate through the

environment.

Guide-

Agent

Agent

Door-

Agent

UserAgent

InformationAgent

CVWAgent

CVWAgent

CVW

CVW

CVW

Multicast Agent Communication

Multicast Net Agent Net

CVW-

AgentGUI

CVW Core

Agents

ASAP


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Giving a tour: As virtual environments usually consistof many rooms and places, the guide can supply a tour

and explain the most important features. The

GuideAgent therefore contacts an InformationAgent,

which has all relevant sites, their position within the

environment and the relating facts in its database. Theuser has the possibility of following the guide on his own

as well as choosing the option that the guide drives the

user's graphical representation. The tour can be quit at

any time.

Information about participants: Participants have thepossibility to be additionally represented by UserAgents.

These agents have more information about their owner,

for example real and company name, real world location,

and interests. The GuideAgent keeps track of visitors to

the workspace and offers the possibility to get a directory

of participants and their current position in the

environment. The users can get the information aboutother participants through contacting the guide which

asks the individual UserAgent about their employer to

receive the desired facts.

Another strength of the GuideAgent is its capability to

model the user's behavior and preferences. This refers to

keeping track of preferred means of interaction as well as

recognizing when help is needed. Interaction modes are

multiple.

The field of applications is very wide: not only static

information about objects can be administrated, but also

dynamic and constantly changing situations (for example

people participating in the environment) can be handled.An example application for the first scenario is the

purpose of a guide agent in a virtual museum: it knows all

the information and facts about the displayed pieces of art

and recognizes objects of higher interest on its own when

the user stays longer or requests more information about a

certain exhibit. These preferred objects are incorporated in

the user profile and the guide can adjust its route

accordingly. An example for the dynamic situation is a

company: When you wait for a visitor to contact you, you

are bound to your desk, which means you can not prepare

the next demo or gather all other persons involved in a

meeting. Instead an agent can be responsible to guide thevisitor from the receptionist to the meeting room to save

time. If more people are involved, then this comes to full

effect as the agents take over the task of scheduling as well

as gathering and guiding people to a certain place.

The convenient ways of sharing information are essential

among agents and, at the same time, the major advantage

of using them instead of fixed pieces of software. Not only

the introduction of new agent types and services is easier,

but their cleverness and adaptability offer new means of

using agent technology in virtual worlds to enhance

usability and comfort.

5. APPLICATIONS

The integration of agents into collaborative virtual

environments provides an interesting field of research in

computer science. This chapter describes the two

underlying applications, which were put together by the

development of agents (see Chapter 4).5.1. ASAP

To simplify our work we use A Simple Agent Platform

(ASAP) to build our agents. ASAP provides agent

templates to enable the programmer to develop software

agents easily. During runtime agents use the capabilities of

ASAP: A facilitator, being part of the agent society itself,

offers information about services of other agents. Different

conditioners inform agents about system dependent events

or changes in the state of the computer. Integrated

networking allows communication over different kinds of

networks.

ASAP is an agent platform developed by the InternationalComputer Science Institute (ICSI) and Fraunhofer-

Institute for Computer Graphics (FhG-IGD) and is written

entirely in the Java language. ASAP is a framework,

which helps to develop new agents in an easy and

uncomplicated way by providing agent templates. The

execution of these new agents takes place in ASAP's

runtime environment. The user gets a convenient way to

keep track about all agent actions as this environment

provides a graphical user interface (GUI).

Figure 4: Overview of all components in ASAP

All components of ASAP communicate among each other

through the use of events. This process is based on a

general broadcast of all messages and events to ensure that

all other agents are notified. Figure 4 shows the general

overview of all components in ASAP.

Local Agent 1

Local Agent 2

Local Agent 3

Agent

Controller

Message Handler 1

Message Handler 2

Message Handler n

Event Handlers

Conditioner

Ext. Command

Network

Conn. Type A

Conn. Type B

Conn. Type M

Facilitator

ASAP Core Module

Agent NameService

Other

ASAP

Core

Modules

Events


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The ASAP Core Module represents one agent society. The

Agent Controller is the runtime environment providing the

general user interface to monitor the local agents. In

addition, the controller offers the possibilities to access

system resources. Conditioners alert an agent when a

specified event occurs (for example a time event in thecase of a scheduling agent), or give information about

system resources (e.g. disc space, system load). External

Commands provide the interface to non-agent programs,

which then can be used by the agent or its user.

To contact other agent societies, no matter if they are other

ASAP Core Modules or a third-party platform, ASAP uses

the idea of integrated networking. Different types of

Connections are responsible for a reliable message

transmission. Networks in this case are standard telephone

lines, ISDN connections, ATM links, and the TCP/IP-

based Internet. Due to the open structure of ASAP new

Connection Types can easily be implemented and usedupon request. During runtime, the Network object

autonomously chooses one available connection type to

contact other agents.

Agents know each other only by their name, not by

address. The Agent Name Service converts identification

strings (names) to physical addresses, which reflect the

actual network identifier (e.g. address, port).

5.2. Virtual Emergency Task Force and VirtualShowroom

In the VETAF scenario, a group of experts located

throughout the world meets to discuss a global crisis in a

virtual environment. It is specially designed to supporttheir cooperation, whereas the Virtual Showroom is

mainly intended to demonstrate how virtual environments

can be used in advertising and presentation.

In the scenario, the setting is a virtual room with a 3D-

model of the object of interest suspended in the middle of

the room (Figure 5). The 3D-model in the virtual

environment has different levels of detail and it can be

edited. The possibility to replace it is provided by loading

other objects into the scene (supported formats include

VRML, 3DS, NFF).

The environments are enabled to map additional data onto

the walls. Projection of static data (e.g. blueprints and

diagrams) and video-recordings are practicable. Video

streams are broadcasted into the virtual environment by

other participants or rescue teams on location in the case

of VETAF. Displaying standard Microsoft Windows

applications (PowerPoint, Word) or distributed

whiteboards is also being put into practice.

Figure 5 Virtual Showroom

All participants can talk to each other with full duplex

spatial sound. A chat facility makes it possible to connect

to other participants on low bandwidth networks.

Technical RealizationThe VCE environment can be separated into three major

components: the main VCE (internal communication)

application, the agent platform, and the multimedia

delivery platform. We use the MBone tools for audio and

video communication.

The main VCE application is realized with WorldToolKit,

a portable, cross-platform software development system for

building high-performance, real-time, integrated 3D

applications. VCE renders the virtual environment and

handles the input/output devices (e.g. space mouse,

monitor, shutter glasses). Any transformation or

movement of entities in the environment is sent asprotocol-data-unit (PDU) packets to every other

participant. Communication between multiple participants

is based on the IP multicast protocol.

The spatial audio server, developed at Fraunhofer IGD in

Darmstadt, is based on a client-server architecture.

Different audio sources (e.g. Internet phone, Mediaplayer)

can be related to objects in the virtual scene. These audio

sources are connected as clients to the audio server, which

renders these audio signals depending on the position and

orientation of each source in the virtual scene. The

VETAF application transmits this position and orientation

data via a socket connection to the audio-server.5.3. Other Agents and Future Work

The main task during the development of agents for VR

applications is the exploration of new forms of interaction

with objects and persons in virtual environments like

CVW. This environment shows how 3D graphics can be

used in conference systems in a way that the visitor of the

conference does not have to miss convenient usability and

accustomed surroundings. In the continuing work the

following types of objects will be evaluated:

Before it comes to interaction, the GuideAgent has toget in touch with the visitors. The agent will be equipped


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with different triggers which lead it to recognize a needy

user: if someone gets lost, people tend to stand still, turn

around themselves to get an overview, or run around the

scenario without any destination. The GuideAgent has to

recognize this multitude of different situations and offer

help. At the same time, the agent has to considerprevious experiences with the individual user in order to

distinguish between situations when help is needed and

when not. The agent must not bother the visitors and get

on their nerves by constantly asking if they request help

but at the same time should always be around in case a

question arises. The users themselves will be able to

contact the guide by either approaching it directly,

contacting a service point or wait for the agent to

recognize the "help situation".

Simple objects like walls, which receive an additionalfunctionality by projecting information and by providing

a user interface to web browsers and other commonapplications, are considered. The underlying agent

controls the application and ensures the correct service is

delivered. One example is an advanced search capability

by contacting other agents in combination with common

search engines. Another example is the possibility to

display advertisements, which reflect the users

preferences. The AdvertAgent therefore contacts the

UserAgent and presents special offers depending on the

user's interests.

In the first implementation step, a DoorAgentcontrolling access to virtual rooms has been developed

(see [7] for more information). It is planned to enhancethis agent by applying a keyhole metaphor. In addition,

the ability to push messages through beneath a door is

considered. By using this function, a visitor of the

environment does not have to enter a charge room

himself in order to contact somebody.

The most interesting research task concerns generalobjects which can be brought into the environment.

Those so-called black boxes are universal tools, which

get a functionality and behavior by external programs.

The main problem here is the generality of the objects. It

is intended to make them as universal as possible by

specifying a general purpose API to develop thepossibility for everybody to build agent-object pairs using

ASAP and integrate these pairs into a virtual

environment.

Other possible object-agent classes include cashiers,

hostesses, reporters, and librarians. New agent concepts of

secure transmission of personal data and intelligence by

neural networks have to be evaluated. Cloning of objects

and agents is another interesting field of our research.

6. EVALUATION

The evaluation was performed by asking 12 computer

natives and developers about the usability of the virtual

collaborative environment (CVE) without and with the aid

of guide agents.

6.1. CVE without Agents

When people enter a virtual world, they usually dont

know who is present and what to do in the scenario. This

is the main point, which was criticized. Participantsdemand the implementation of a help desk or a

receptionist. They want maps about the building to see

which rooms may be interesting, where people with the

same interests gather, and to show them a way for

orientation purposes. To help them with navigation, it is

useful to have maps at every junction or central point.

Signposts need to be present as well. It is important for the

users to have the possibility to get information at all times,

as it is the case with directories displayed on walls.

Another point of interest is timetables, so that people can

check where their meeting takes place at which time. It

should also give an overview about the participants withthe possibility to get more information about them on

demand. Interaction with other persons is also requested.

This is not only for social purposes but also an additional

way of getting information.

People had difficulties with large worlds, as there is no

possibility to travel large distances at a short time. The

scenario lacks teleporters, which transport the

participants from one point to a desired destination in no

time. (Several persons mentioned the lacking of this

feature individually.)

Over all, people tended to a setting very close to reality,

where sales personal, guides, receptionists, elevators, and

maps are common and helpful.

6.2. CVE with Agents

After integrating agents into our collaborative virtual

worlds, people are much more satisfied concerning

usability and navigation. They like the constant

availability of a guide agent and its way of interacting.

They emphasize that it is very important for the agent to

be polite and to answer reliably. The hierarchical

arrangement of information and therefore fast access to a

wanted fact is very important.

The navigation help of the new agent was highlywelcomed. As described in Chapter 4, the agent offers the

possibility to guide the user to a person or room in the

scenario. People liked the possibility to leave this guidance

at any time on their own whenever something interesting

appears on their way, and to continue later on. Probands

welcome the implementation of the tour feature, providing

detailed information about the setting.

But there are still problems to be solved: First, the agent

has to adapt on users and their behavior in case they need

help. Currently, some users are annoyed when the guide

repeatedly asks them if they request aid. Second,


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interaction with buttons is not enough. People requested a

more natural inaction possibility like speech recognition.

Third, the functionality of the guide agent should be

extended. Users lack the possibility to send short notices to

other participants through the use of the guide. Currently,

there is no possibility for one user to tell another thathe/she is coming to a meeting point and that the other

person is supposed to wait there. The tours and tutorials

also have to be designed more complex in order to provide

more information and offer more possibilities to the user.

Forth, the teleporter function as an alternative to the

regular tour has to be implemented.

7. RELATED WORK

In the Virtual Polis project (Carnegie Mellon University of

Pittsburgh, PA, USA), agents are used to popularize the

simulated world with people and animals. The main point

of interest is a simulation of behavior close to reality [8].

At the University of Southern California virtual realitiesare used to visualize air combat simulations [5]. Every

helicopter and plane is linked to an agent, which controls

the correct execution of the individuals mission. Team

coordination between agents, and recognition and

correction of occurring errors are the main aims in this

project. The schematic visualization is used to control and

monitor the resulting activities of agents.

8. CONCLUSION

Fraunhofer IGD is focusing its research efforts on

determining how collaborative virtual environments can

help transform the workplace into a shared environment,

allowing real-time interaction between people regardless oftheir physical location.

Current research includes work on a general architecture

for applications in collaborative virtual environments. This

architecture supports current applications as well as

research in the areas of distributed simulation, agents in

virtual environments, and networking for large-scale

virtual environments.

Especially agents play a significant role in the

maintenance and processing of large amounts of data. The

importance of this technology will extend across many

different application domains. The ongoing work explores

the application of agents in virtual worlds. The problemdomain includes both simple tasks, such as management of

projection walls, as well as complex processes, such as

path planning and controlled access to resources. All of

these tasks can be managed, simplified and made

accessible to the user by the use of agents.

In this article we introduced the integration of

collaborative virtual environments and intelligent agents to

enhance the usability of 3D user interfaces. At the present

time, stable prototypes of the virtual environment system

VCE and the agent platform ASAP exist. The scenario

VETAF was demonstrated at several trade shows (e.g.

SIGGRAPH 97 in Los Angeles, ACM 97 in San Jose, and

the G7 Meeting in Bonn). By integrating both these

research projects, this work creates a framework for

extending objects in virtual cooperative environments by

high level behaviors. Using the resulting system, different

agent behaviors and their utility to the users can beevaluated. Experiments with the already implemented

agents VRDoorAgent and VRDeputyAgent showed a

significant simplification of the tasks and increased

usability for the user. These improvements were made

possible by the combination of current work in two

important areas of Computer Science.

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Documents

Autonomous Agents in Collaborative Virtual Environments