3D Web Agents in Distributed Logic Programming

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3D Web Agents in Distributed Logic Programming

• Zhisheng Huang, Anton Eliens and Cees Visser
• huang,eliens,ctv_at_cs.vu.nl
• Intelligent Multimedia Group
• Vrije Universiteit
• The Netherlands

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• 3D Web Agents are intelligent agents whose
  avatars can interact with users via Web
  browsers. These Web-based 3D avatars are usually
  constructed by means of the Virtual Reality
  Modeling Language VRML.

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Outline of This Talk

• 1 Main Features of 3D Web Agents
• 2 Requirements of Programming/Specification
  Languages for 3D Web Agents
• 3 Distributed Logic Programming Language (DLP)
  for 3D Web Agents
• 4 Examples
• 4.1 VRML-based Multi-User Soccer Game
• 4.2 Facial Animation in DLP
• 5 Conclusions

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Main Features of 3D Web Agents

• Cross-Platform Accessible for any Web browser
  with a VRML viewer
• Mobility Accessible from anywhere over the
  Web
• Reactivity in Real Time Can react in real time.
  No heavy rendering delay
• Flexibility Rule-based knowledge representation
  makes the changes of behaviors rather easy. Need
  no re-programming.

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Requirements of General Programming/Specification
Languages for 3D Web Agents

• VRML EAI support, like Java
• Multi-threaded control
• Object-Oriented
• Declarative language rule-based knowledge
  representation/specification, like Prolog
• Distributed communication/computation
  capabilities

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Architecture of Web AgentsExtended BDI Model
Desire
Intention
Belief
effectors
sensors
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Sensor/Effector Primitivesfor 3D Web Agents
getPosition(Object, X, Y, Z) setPosition(Object,
X, Y, Z) getRotation(Object, X, Y, Z,
R) setRotation(Object, X, Y, Z,
R) getViewpointPosition(Agent, X, Y,
Z) setViewpointPosition(Agent, X, Y,
Z) getViewpointOrientation(Agent, X, Y, Z,
R) setViewpointOrientation(Agent, X, Y, Z, R)
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Distributed Logic ProgrammingDLP
Distributed logic programming Eliens1992
combines logic programming, object-oriented
programming and parallelism.
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DLP has been extended with a 3D VRML Client
Interface Library, which includes the
sensor/effector primitives for 3D web agents.
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Main Features of DLP for 3D Web Agents

• Multi-threaded Language modeling of
  independent intra or inter agent activities
• Distribution high-level TCP/IP based facilities
  for distributed communication, thus DLP can be
  used to build virtual multi-user communities
• High-level communication Protocols support
  for Agent Communication Languages (ACL)
• Declarative Language rule-based knowledge
  representation

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Benchmark ExampleSoccer games on the Web
Http//wasp.cs.vu.nl/wasp/
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Features of VRML-based Soccer Games

• Multi-Agent Systems
• Multi-User Systems
• Reactivity
• Cooperation / Competition
• Dynamic Environments
• Distributed Communication

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(No Transcript)
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Cognitive loopsensing-thinking-acting
thinking
acting
sensing
Belief
Intention
Desire
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Cognitive model of soccer game
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Action Specification in Agents Knowledge-Bases

• look-at-ball
• run-to-ball
• shooting
• passing
• move-around
• run-and-trace
• near-ball-then-kick
• ...

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DLP code examplethe action Look-at-ball
look_at_ball(Player,Ball) - getPosition(Player,
X,_,Z), getPosition(Ball, X1,_,Z1), X \
X1, !, R is atan((Z-Z1)/(X-X1)) -
sign(X-X1)1.57, setRotation(Player,0.0,
1.0, 0.0, R).
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DLP code examplethe action find-how-to-react
findHowtoReact(Agent, Ball, shooting)- getPosit
ion(Agent,X,Y,Z), getPosition(Ball,
Xb,Yb,Zb), gatePosition(Agent,Xg,Yg,Zg),
distance(X,Y,Z,Xb,Yb,Zb,Distb), distance(X,Y,Z,X
g,Yg,Zg,Distg), Distb lt kickableDistance Distg
lt kickableGoalDistance.
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Agent Communication Language

• agent communication languages (ACL) are used to
  serve as a high-level communication facility.
• KQML and FIPA ACL which are based on speech act
  theory are popular agent communication languages.
• A message in ACL usually consists of a
  communicative act, a sender name, a list of
  recipients, and additional content.
• Communicative acts like 'tell', 'ask', and
  'reply', are used to identify the communication
  actions which may change the mental attitudes of
  the agents.

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VRML-based client-server Architecture
server
VRML EAI
VRML EAI
VRML EAI
browser
browser
browser
client
client
client
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Shared Object

• A shared object is an object whose state and
  behavior are to be synchronized across multiple
  clients

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3D agent-based virtual communities

• Virtual environments with embedded agents
  autonomous agents are participants in virtual
  communities.
• Virtual environments supported by ACL
  communication Agent communication
• languages are designed to provide a high-level
  communication facility. The communication between
  the agents can be used for the realization of
  shared objects in virtual worlds.

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PAMELA as Presentation AgentFacial Animation
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H-anim 1.1 Compliant Avatars
The intelligent agent avatars are designed to be
H-anim 1.1 compliant, based on the specification
for a standard humanoid proposed by Humanoid
Animation Working Group.
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DLP code exampleEyebrow Up and Lip Move
eyebrowUp_lipMove(Times,Interval, Range)
- getPosition(eyebrowRight, X1,Y1,Z1), getPosit
ion(eyebrowLeft, X2,Y2,Z2), eyebrow_up(eyebrowRig
ht, 0.01), eyebrow_up(eyebrowLeft,
0.01), lipMove(lowerlip,Times,Interval,Range), s
etPosition(eyebrowRight, X1,Y1,Z1), setPosition(e
yebrowLeft, X2,Y2,Z2).
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Conclusions

• A technology for 3D web agents needs a general
  programming / specification language which merges
  aspects of object-oriented languages, web3D-
  oriented languages, and declarative languages.
• The distributed logic programming language DLP
  is a general programming/specification language
  for 3D web agents.
• DLP is a convenient tool for the implementation
  of 3D web agents.