Sedvice: Triple-Space Computing Exploration Platform
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Transcript of Sedvice: Triple-Space Computing Exploration Platform
1 © 2008 Nokia 29 April 2008 / IJO / Confidential
Sedvice: Triple-Space Computing Exploration Platform
Ian Oliver
Tripcom Workshop
Galway
29 April 2008
Nokia Internal Use Only
2 © 2008 Nokia 29 April 2008 / IJO / Confidential
Aims
• Investigate new/novel mobile-device architectures
• On and off device
• hardware/software
• Specific focii
• universal connectivity
• interoperability (via the Semantic Web)
• modularity
• power consumption
• Buzzwords
• Web 3.0
• Dynamic Adaptive Semantic Web
Nokia Internal Use Only
3 © 2008 Nokia 29 April 2008 / IJO / Confidential
Pre-History (2004-2006)
• Network on Terminal Architecture (NoTA)
A Device
SS1
SS2
SN SN
SN
SN
Resource Manager
H_IN
H_IN
H_IN
L_IN
L_IN
Network
L_IN
Nokia Internal Use Only
4 © 2008 Nokia 29 April 2008 / IJO / Confidential
History (2006-2007)
• Sedvice/M3
• interoperability (via sematic web constructs)
• architectures
• Triple-Space based distributed computing platform
• Built upon Wilbur
• move to investigate distributed computing
Nokia Internal Use Only
5 © 2008 Nokia 29 April 2008 / IJO / Confidential
The Present - SmartSpaces
• Nokia Triple-Space Based Computation Platform (Sedvice)
• A Localised Information Sharing Mechanism
• Abstraction from the device
• Abstraction from control flow
• Abstraction from services
• Abstraction from application
• An information centric environment for the declarative construction of applications from the manipulation of information
• An environment which allows real-time usage of semi-structured information with an emphasis on intentional semantics
Nokia Internal Use Only
6 © 2008 Nokia 29 April 2008 / IJO / Confidential
Information
• Data is expressed as a directed graph structure, obstensibly represented in RDF
• Ontology provides structure and a default semantics to this
• The semantics of the ontology is grounded in real-world concepts
• However, any piece of information has semantics given by the creator of that information which is the intent of that information
• Which is further complicated by the fact that some writers might ascribe a different intent to that information
• Which if you’re lucky intersect such that the intent of both parties is understood
Data
Ontology/Semantics
Real-World W
riter’s In
ten
t
Re
ad
er’s In
ten
t
Nokia Internal Use Only
7 © 2008 Nokia 29 April 2008 / IJO / Confidential
Sedvice Architecture
• Spaces
• represented by one or more SIBs (Semantic Information Broker)
• Contains
• membership & policy management
• distribution protocols (internal distribution)
• information processing and rewriting
• information storage (Wilbur)
• may be connected to external storage directly
• Nodes
• actors/agents
• autonomous, concurrent
• Communication
• information based
• structured as RDF
• not considered ”data”
• no control flow
• may be made ”outside” of the system via NoTA, UPnP, Webservices etc
• semi-structured information
• no strict ontology conformance
• inconsistent information allowed!
• semantics of information, belief and truth maintenance responsibility of the reader (agent/actor)
• free logics
• depends upon the Space, but 2-valued, 3-valued, 4+
• modal, subjective, classical...
• notions of unknown () are probably desirable
Nokia Internal Use Only
8 © 2008 Nokia 29 April 2008 / IJO / Confidential
Functionality
• Basic functionality
• insert
• retract
• non-monotonic mode of operation only
• query (synchronous)
• set/bag, full results/announce
• subscription (asynchonrous)
• set/baq, full results/delta/announce
• WQL
• deductive closure calculation
• Direct RDF triple queries
• no reasoning
• Formal Specification over Architecture using Alloy
• Policy/Security
• join/leave
• invite/remove (real soon now)
• information based policies (2009)
• Advanced
• triple rewriting and optimisation
• Implementation/Productisation
• Python 2.5.1...Symbian from 2H2008
• C++/OpenC core due 2H2008
• Client libraries
• Python, C, OpenC 1H2008 (support for Flash)
• C++, Java, 2H2008
} transactional
Nokia Internal Use Only
9 © 2008 Nokia 29 April 2008 / IJO / Confidential
Triples++
• Triples are input as (s,p,o) but are stored internally as (s,p,o,*ptr)
• The *ptr is a URI which points to a structure which may contain whatever required information is necessary
• typically:
• meta-data
• source
• etc...
• *ptr may be NULL
• Triple reification
• possible but generally switched off
• generates too many additional triples
• not elegant enough...*ptr does it better
• 400-500% overhead
• not everything generates triple-Ids
• semantics is awful
• literals are !rdf:properties?
s oURI p
id
!ns:subject !ns:predicate
!ns:object
Nokia Internal Use Only
10 © 2008 Nokia 29 April 2008 / IJO / Confidential
Pictorial View (SIB)
Deductive Closure Engine
Information Store
WQL RDF Query Insert/Retract Engine
Object Rewriter
Dynamic Reasoners
Connectivity
IP BT UMTS ...
SparQL
External
Storage
NOT ALL COMPONENTS SHOWN
Nokia Internal Use Only
11 © 2008 Nokia 29 April 2008 / IJO / Confidential
Pictorial View (SIB+Nodes)
Deductive Closure Engine
Information Store
WQL RDF Query Insert/Retract Engine
Object Rewriter
Dynamic Reasoners
Connectivity
IP BT UMTS ...
SparQL
External
Storage
Connnectivity
Node Library
Ontology Convenience Libraries
Nokia Internal Use Only
12 © 2008 Nokia 29 April 2008 / IJO / Confidential
Pictorial View (Spaces+Nodes)
SIB
SIB
SIB
SIB SIB
SIB
SIB
Node
Node Node
Node
Node
Node
Node
Node
Node
Node
Devices...?
Nokia Internal Use Only
13 © 2008 Nokia 29 April 2008 / IJO / Confidential
Space Distribution
• Spaces are self-contained
• Information may be distributed amongst the SIBs within a space
• distributed insert/retract semantics
• distributed query semantics
SIB
SIB
SIB
SIB
Information Store
SIB
Nokia Internal Use Only
14 © 2008 Nokia 29 April 2008 / IJO / Confidential
Space Distribution
• Spaces are self-contained
• Information may be distributed amongst the SIBs within a space
• distributed insert/retract semantics
• distributed query semantics
• deductive closure calculation:
• D(S1(Q)S2(Q))D(S1 (Q)) D(S2 (Q))
• Distributing the information store may be made...not currently considered - databases do this so much better!
SIB
SIB
SIB
SIB
Information Store
SIB
Information Store
Information Store
Nokia Internal Use Only
15 © 2008 Nokia 29 April 2008 / IJO / Confidential
Space Relationships
• Subspaces, space relationships were removed as being ”first class” elements
• Can be ”lifted” into Nodes
• Good features:
• any relationship can be implemented
• Bad features:
• cyclic relationships
• harder to ensure relationship semantics
SIB
SIB
SIB
Node1
SS1 is a ”subspace” of SS2 according to some relationship implemented in Node1
SS1
SS2
Nokia Internal Use Only
16 © 2008 Nokia 29 April 2008 / IJO / Confidential
Security, Policy & Trust
• Not implemented !!!
• not yet!, 1H/2H 2008ish...
• privacy is over-rated anyway
• major concern and requires a lot more research
• unclear at this time how these are going to be implemented
• Join/Leave mechanisms
• Node -> Space request
• Invite/Remove mechanisms
• Space -> Node request
• Security
• definition of ?
• Policy
• triple/uri based
• larger structures?
• DL based + reasoning mechanism
• Trust
• not considered in detail
• subjective logics
Nokia Internal Use Only
17 © 2008 Nokia 29 April 2008 / IJO / Confidential
Static Reasoning and Triple Rewriting
• WQL queries utilise the calculation of a deductive closer dynamically
• no static creation of triples that can be inferred
• rdf!type under rdf!subClass
• rdfs!Property
• owl:sameAs
• Triple rewriting
• object type inferrence
• object type rewriting
• BLOB, large object optimisation
• off-Space storage
• FLICKR, YouTube...
• Transaction rewriting
• {insert(a), retract(a)} ◊~ =
• plug-in logic system
• insert and retract are transactional
• transactional = multiple i/r’s atomically
• all operations are atomic invidiaully
• query and subscribe aren’t – you get whatever
Nokia Internal Use Only
18 © 2008 Nokia 29 April 2008 / IJO / Confidential
Dynamic Reasoning
• Intenal Nodes to a Space
• Typical functionality
• Ontology Adherence
• Ontology Repair
• Differences from Nodes
• guaranteed execution
• easier to the mathematics/semantics
• scheduling environment
• specific ordering of reasoners
• Scheduler
Buffer incomming inserts/retracts
object-type rewriting
transaction rewriting
update store
schedule dynamic reasoners
process pending queries/subscriptions
Nokia Internal Use Only
19 © 2008 Nokia 29 April 2008 / IJO / Confidential
Applications
• Semantic Web has no killer application
• Semantic Web is the killer appplication
• Demo applications
• Chat
• investigations into coordination, distribution and general application design
• MediaPlayer
• canonical Nokia application
• UPnP Integration
• UPnP CDS + device + family integration
• ”family” UPnP
• Health and Wellbeing
• Nokia SportsTracker
• Location
• GPS integration
• Personal Media
• photographs + identity + location + external storage
• context collaction
• NLP interfaces
• What is an application?
• not monolithic
• distributed
• distribute over functionality?
• control flow/coordination?
• Ontology, ontology, ontology, ONTOLOGY!
• ”ontologisise” everything...
Nokia Internal Use Only
20 © 2008 Nokia 29 April 2008 / IJO / Confidential
Demo Setup
• 1xWindows PC
• 1xLinuxPC
• 1xN770 (Linux)
• 3xN800(Linux)
• 1xN95 (Symbian, Java)
• 1xSolaris Server (not shown)
• AdHoc Network (+ some routing to internet)
• WLAN/IP Based
• SIB running on N800 (centre picture) • python version
• 2 Spaces + Nodes including: • Chat (approx 10 Nodes, 3 humans)
• Weather aggregator
• Chat-Weather interface
• Everything Python (2.5.1) except hand written, adhoc, MIDP Java implementation
Nokia Internal Use Only
21 © 2008 Nokia 29 April 2008 / IJO / Confidential
Ontological Considerations
• Everything needs to be defined via ontology
• though no strict adherence to the ontology is required
• inconsitency and abuse of meta-levels, typing etc is fine
• see RDF Model Theory for a discussion of ZF axioms
• Application Development
• ontology centred
• automatic convenience library generation
• distribution of functionality
• no control-flow
• alegbraic structures/lambda calculus/pi-calculus
• Scope Rules
• embedding query (WQL) in the RDF store
• dynamic/on-the fly convenience library generation
• Reflection
• internal processing of scope rules
• embedded execution
• Retraction
• notions of aggregation/composition
• cf: UML
Nokia Internal Use Only
22 © 2008 Nokia 29 April 2008 / IJO / Confidential
Demo
• on demand...
Nokia Internal Use Only
23 © 2008 Nokia 29 April 2008 / IJO / Confidential
Questions?