Prof. Dr. Thomas Schwotzer
Computer Science / Mobile Applications
thomas.schwotzer@fhtw-berlin.de
Shark Framework
(Building Context Aware P2P
Applications)
work in progress

TOC
• Knowledge
• Knowledge Exchange
• A model of Knowledge Exchange Process
(Shark)
• A knowledge exchanging software engine
(Shark Engine / Shark Framework)
• Examples
• Status
• Summary

Boring....
• Some of your might know Shark
– 2001 – 2006 TU Berlin:
• How to apply Semantics to Mobile World
• Mobile Shared Knowledge
• 1st paper 2002, several technology studies, some
open source projects started
• 2006 PhD
• work stopped
• Other scientists know such situations :-(
• Since April 2008 relaunch
– still an issue
– ocean of time, enthusiastic people/students

Message
• Shark Framework will be finished
• Will be maintained
– at least in the next 28 years
• This isn't and won't be my project
• Shark stands for Shared Knowledge
• Let's share it
• Open Source with LGPL (sourceforge)
• www.sharksystem.net

Knowledge
• AI / Knowledge Representation:
– An ontology is / contains / comprises
knowledge
– A Topic Map is knowledge
– Knowledge can be stored in a Topic Map
– set of facts (e.g. represented by PROLOG)
• Definition by structure

Knowledge (2)
• Knowledge Management
– Knowledge is something that helps people to
perform a task / to solve a problem
– Process oriented view on knowledge
– BTW: subject isn't anything!
• Somebody must be interested in it!
No intelligent life -no subjects.
• Implications:
– A document can be knowledge for person A
but just (electronic) paper for B , e.g.
• due to lack of background knowledge
• can't read the format no PDF reader available

Knowledge (3)
• Implications:
– A document can be knowledge for person A
but just (electronic) paper for B , e.g.
• due to lack of background knowledge
• can't read the format no PDF reader available
• can't understand the spoken, programming,
description or whatever language

Knowledge (4)
• Is a document D knowledge?
– If it helps a person A in a given situation – yes
D is knowledge for A in this situation
– If not: D is no knowledge
• It depends on the context
– issuer, receiver, current situation (in its broadest
possible sense)

Knowledge in Topic Maps
• Information resources can be knowledge
– Can contain descriptions that help
• An association of Topics can be knowledge
– Can help to find relations or IR
• Topics
– Can be knowledge
if representing subjects that help
– Can be context
and help to find knowledge

Is knowledge true?
• With given definition – it's impossible to
decide
• No objective independent instance which
could decide
• Semantic networks (e.g. Topic Maps)
represent meanings / statements of the
authors
• Known concept: Reification

Knowledge – a picture
Context
Person
Information
Statement
Knowledge Particle
= Statement + Issuer

Knowledge Exchange - Example
2 „That's what I mean“ „1… that's interesting“
3 „I have some documents about it. W ant to have look?“
4 „Please.“
Mobile Person Mobile Person
5 „Sounds good. Thanks!
“

Steps
• Negotiation
– Who has information about what topics
– Who is interested and allowed to send/receive
information
– Implicitly: take context into account
– Leads to an exchange context
• Knowledge Exchange

Different to Knowledge Retrieval
• Simple query doesn't produce knowledge
• Full text search on e.g. “music”
• semantic search (e.g. by TMQL) not
fundamentally better
• Context is not described explicitly
– Background knowledge
– Situation
– ...

Knowledge Exchange Process
potential sender potential receiver
KB KB
remote identity remote identity
+ +
remote interests Assimilation remote interests
+ Extraction +
sending interests receiving interests
+ +
Knowledge
environment = environment
Particle
(eavesdropping, ..) (eavesdropping, ..)
* I confess: The term assimilation is stolen from the Borg in Star Trek. Hope they'll never find out.

Extraction / Assimilation
• Extraction
– Process creates a knowledge
– wants receiver to integrate this knowledge
– A sender can
• lie
• isn't an expert
• Assimilation
– Process that integrates (parts) of received
knowledge

Knowledge Exchange Protocol (KEP)
• Interest
– exposes topics of which knowledge is welcome
• Offer
– exposes topics of which knowledge can be sent
• Accept
– sent from a receiver to a dedicated sender
– sents a number of topics
• Insert
– sent from a sender to a dedicated receiver
– Knowledge particle

KEP Example 1
Peer Musik / * Musik / * Peer
S R
Establish connection / Identifying
interest(musik)
offer(musik)
accept(musik)
extract(R, Musik);
insert(KnowledgeParticle kp)
assimilate(S, kp);

KEP Example 2 (mobile leaflet)
Peer Musik / * Musik / * Peer
S R
Establish connection / Identifying
interest(musik)
extract(R, Musik);
insert(KnowledgeParticle kp)
assimilate(S, kp);

KEP Example 3 (hide interests)
Peer Musik / * Musik / * Peer
S R
Establish connection / Identifying
accept(*)
extract(R, Musik);
insert(KnowledgeParticle kp)
assimilate(S, kp);

Shark Data Model (in UML, sketch)
Topic 1..* Peer
1
1..*
*
Information Interest

Shark Data Model (as TM)
Type Peer Peer
Topic1 A B
Type
Remote Peer
Topic2 Peer
Topic Anonymous
Sending
Receiving
Interest
T represents
a special interest

Shark Peer
• Software
• Implements extraction and assimilation
• Implements KEP
• Manages Knowledge Ports which store
interests
• Process
– Observes environment
– If remote peer is detected:
– run KEP (in defined flavour)

Autonomy
• Exchanges knowledge only based on rules
described in KPs
• Rules can be changed locally – no
interaction with any server required

Flow of knowledge
Alice Bruce
I agree
new idea
I think
Alice I think
Bruce
author author
Alice
Externalization

Collaboration
M-TM-P
M-TM-P M-TM-P M-TM-P
M-TM-P
company /
institute working
(trusts its TM
experts)
Topic Maps
expert
member /
employees

Knowledge Flow Management
M-TM-P
TM
M-TM-P M-TM-P M-TM-P
TM TM
M-TM-P
company /
institute working TM
(trusts its TM
experts)
Topic Maps
expert
member /
employees

Implicit ontology expansion
Music/*/* Music/*/*
Music
HipHop
Music
MP3
HipHop
File
MP3
File

Individuals KB = patchwork
M-?-P

Architecture
Knowledge Ports / KEP
Network
Knowledge Base Protocol
Environment
Sensors
TM Service BT
FS TM Security TCP UDP
J2ME Mng L2CAP

Some classes
Environment KnowledgeBase Peer
SimpleEnvironment KnowledgePort
fs.KnowledgeBase
// single thread
inMemo.
KnowledgeBase
tinyTIM.
KnowledgeBase

Code sample
KnowledgeBase = new tinyTIM.KnowledgeBase();
Environment env = new SimpleEnvironment();
Peer myPeer = new Peer(kb, env);
Context any = new Context(Context.ANY);
RemotePeer rPeer = new
RemotePeer(RemotePeer.ANONYMOUS)
myPeer.createIKP(any, any, rPeer);

Code sample - result
myPeer
*/*/*
single threaded
tinyTIM TCP based
environment

Mobile Communities
Mobile
Find peers/people with
similar interests and exchange
knowledge/information
Mobile Phone

Location Based Services
Mobile
Mobile
Hotspot
Send information to passer-by Mobile

Collaboration / Semantic Grid
PC
Mobile
PC
Exchange documents, rumours, links

Work in progress
• Implementation started April, 2008
• Shark-FW-Core exists
• KEP exists, used exchange format
– compressed proprietary format
– Topic Maps
• Protocols
– TCP, UDP work
– BT Prototyp
• Knowledge Bases
– Filesystem – Prototyp
– tinyTIM – implementation has begun

Next steps / priority list
• Applications
– Collaboration platform
– Mobile Community Application
• Knowledge Base
– J2ME
(revive the TM4J2ME project (sourceforge)
– Jena-FW (RDF) (I'll be a traitor, sorry!!)
• Protocols
– Stable Bluetooth implementation
– HTTP

Distributed evolutionary Ontologies
• Knowledge can be
– Information resources
– Topics and Associations
• A P2P Knowledge Exchange can lead to
changes in Topic Maps
• Kind of evolutionary process
– Any receiver can accept or drop changes
– “survival of the fittest concepts”
– Might lead to a drift and groups of peers
sharing same / similar ontologies

Summary
• Shark model describes the process of
knowledge exchange
• Shark Framework implements this model
• basis for number of applications
• Buzzwords for Shark Applications
– Semantic Grid Applications
more specific mobile Topic Grid Apps
– context aware P2P Apps