Open Semantic Service Networks: Modeling and Analysis

Departamento de Engenharia Informática
FCTUC FACULDADE DE CIÊNCIAS E TECNOLOGIA da UNIVERSIDADE DE COIMBRA

Open Semantic Service Networks:
Modeling and Analysis
Jorge Cardoso (1), Carlos Pedrinaci (2), and Pieter De Leenheer (3;4)

(1) CISUC, Department of Informatics Engineering
University of Coimbra, Polo II, 3030 Coimbra, Portugal
jcardoso@dei.uc.pt

(2) Knowledge Media Institute, The Open University,
Milton Keynes, MK7 6AA, UK
c.pedrinaci@open.ac.uk

(3) The Network Institute, VU University Amsterdam,
1081 HV Amsterdam, The Netherlands
pieter.de.leenheer@vu.nl
(4) Collibra nv/sa, Brussels, Belgium

// 07/08 February 2013 //
International Conference on Exploring Service Science
Porto, Portugal

Cardoso, J.; Pedrinaci, C. and Leenheer, P. D Open Semantic Service Networks: Modeling and Analysis. In 4th International Conference on
Exploring Service Science (IESS 1.3), pages 141-154, Springer, LNBIP, Porto, Portugal, 2013.

The importance of services
Service
economies

Self-services

Consulting IT Services Cloud services

Software

Manual Semi-automatic Fully Automated

2013 Genessiz: Center for Large-Scale Service System Research 2

…energy grids, water systems, wireless mobile networks...

The importance of networks

World Wide Web Linked Data Social Networks

Financial/Political Networks Railway Network Food chain Networks

Internet Academic citations
Information Patent citations
Software classes
Airline routes Networks Word classes
Railway routes Preference
Roadways WWW
Telephone Technological P2P
Delivery Networks
Electric power grids
Electronic circuit
Service
Science

Handbook of
Service Science (2010) Service
Service
Networks
Networks

Network
Science Metabolic pathways
Social Protein interactions
Friendship Networks Genetic regulatory
Sexual contact Neural
Intermarriages Blood vessels
Business Relationships Biological Food web
Science on Networks
Special Issue (2009) Communication Records Networks
Collaboration

…definitions…
“A service network is defined as a graph structure
composed of service systems which are nodes
connected by one or more specific types of
service relationship, the edges.”

”A service system is a
functional unit with a
boundary through which
interactions occur with
the environment, and,
especially, with other
service systems.”!


_Business services_
_Business services_ _Business services_
_Business services_
_Business services_
_Business services_
_Business services_
_Business services_
_Business services_
_Business services_


Service Network Modeling
_Business services_


_Business services_
_Business services_
_Business services_
_Business services_
2013 _Business services_
Genessiz: Center for Large-Scale Service System Research 6
_Business services_

OSSN Construction
• Similar to LD, SN, and Global
WWW Glo scale
– Leaves decisions in the bal
hands of market player Supply
– Consumers indicate Supply Networks
providers
– Increase transparency Supply
Chains

Single
Bottom-up Services

Beyond dyads!
2013 Genessiz: Center for Large-Scale Service System Research

Basic Building Blocks
Service System Service Relationship

Open Semantic Service
Relationship (OSSR)
• Service description
• Follows Linked Data principles • Relationship description
• Simplicity for computation and • Interconnects services
modeling
• Multi-layer
• Reuse existing vocabularies
• Follows Linked Data principles
• Means for publishing and
interlinking distributed data • Reuse existing vocabularies
• [CPL+13][CM12][CPL+12][CB • Means for interlinking service
M+10] descriptions/systems


Service Systems


http://www.linked-usdl.org/

www.internet-of-services.com

Linked USDL:Core
Linked USDL:Pricing
Linked USDL:SEC
Linked USDL:SLA

Service Description
Modeling http://aws.amazon.com/ec2/


:pricing_EC2_Small_EU_Windows_ReservedInstance_Light_1yr a price:PricePlan ;
dcterms:description "Price plan for a 'Small' EC2 Reserved Instance in Europe with Windows, light
utilization and a one year contract duration."@en ;
@prefix price: <http://www.linked-usdl.org/ns/usdl-pricing#>
price:hasContractDuration
[ a gr:QuantitativeValue ;
gr:hasValueInteger "1" ;
gr:hasUnitOfMeasurement "ANN" ] ;
price:hasBillingCycle
[ a gr:QuantitativeValue ;
gr:hasValueInteger "1" ;
gr:hasUnitOfMeasurement "MON" ] ;
price:hasPriceComponent
:priceComponent_Small_EU_Windows_ReservedInstance_Light_1yr_General_Upfront ,
:priceComponent_Small_EU_Windows_ReservedInstance_Light_1yr_General_Hourly ,

:priceComponent_Small_EU_Windows_ReservedInstance_Light_1yr_General_Upfront a price:PriceComponent
;
dcterms:title "General costs upfront"@en ;
dcterms:description "One-time fee for general usage of the instance."@en ;
price:isLinkedTo
…
price:hasPrice
[ a gr:UnitPriceSpecification ;
gr:hasCurrency "USD" ;
gr:hasCurrencyValue "69" ;
gr:hasUnitOfMeasurement "C62" ] .


Legal @prefix legal: <http://www.linked-usdl.org/ns/usdl-legal#>

:legal_Amazon a legal:TermsAndConditions ;
dcterms:title "Amazon Web Services LLC's legal statements"@en ;
dcterms:description "Amazon Web Services LLC's legal statements are accessible at
'http://aws.amazon.com/legal/'. Please consult this website for further information"@en ;
legal:hasClause
[ a legal:Clause ;
legal:name "AWS Customer Agreement" ;
legal:text "http://aws.amazon.com/agreement"@en ] ,
[ a legal:Clause ;
legal:name "AWS Services" ;
legal:text "http://aws.amazon.com/serviceterms"@en ] ,
[ a legal:Clause ;
legal:name "AWS Acceptable Use Policy" ;
legal:text "http://aws.amazon.com/aup"@en ] ,
[ a legal:Clause ;
legal:name "AWS Trademark Guidelines" ;
legal:text "http://aws.amazon.com/trademark-guidelines"@en ] ,
[ a legal:Clause ;
legal:name "AWS Sites" ;
legal:text "http://aws.amazon.com/terms"@en ] ,
[ a legal:Clause ;
legal:name "Privacy Policy" ;
legal:text "http://aws.amazon.com/privacy"@en ] ,
[ a legal:Clause ;
legal:name "AWS Tax Help" ;
legal:text "http://aws.amazon.com/tax-help"@en ] .


Standardization
• W3C Standards
– HTML, Ajax, HTTP, XML, WSDL, …
– http://www.w3.org/

• OASIS Standards
– TOSCA, USSI, WS-*, ebXML, …
– http://www.oasis-open.org/

• OMG Standards
– BPMN, UML, CORBA, XMI , …
– http://www.omg.org/


Service Relationships


Centrality: 23

Service Network Analysis


Self-organization, emergent patterns,
dynamic, complex, etc.,

Service Networks
Atomic Dyad Ego
service systems service networks service networks
1 2 3

Service networks
4

Power-law


Networks and Vulnerability
• Protecting just 4 nodes
made a system less
vulnerable

• Left
– all communications
servers are coupled to the
power grid

• Right • Circles represent a power grid
• Diamonds a communications
– Four are decoupled network
– Lower vulnerability • Colors show the probability that a
node fails after 14 servers fail

Source: C.M. Schneider et al/arxiv.org 2011; Map: Geoatlas/graphi-ogre, adapted by T. Dubé
2012 Genessiz: Center for Large-Scale Service System Research
http://www.sciencenews.org/view/feature/id/343939/description/When_Networks_Network 20

Examples of questions to ask
• We assumes that – Do monopolies or
services are all oligopolies exist in the
energy sector in the US?
interdependent
– Service are provided
and services consume – Is the financial service
other services network stronger or
weaker than it was 5
years ago?
• SNA can ask and
answer questions such – What service sector has
as: the stronger
competition in Georgia?


Dynamic OSSN
• OSSN model
– Linked USDL and OSSR do not provide
constructs to capture the dynamic behavior of
service networks
– In other words, they can only capture static
snapshots of service networks

• This is a limitation of several approaches
– E3value [12], e2service [13], SNN [14], Allee
modl [15], value chains, value nets, and value
networks [17].


Preferential Attachment (PA) System Dynamics (SD)
accounts for accounts for

Unified Service Open Semantic
Description Language Service Relationship
(*- USDL) (OSSR)
models models

Service system

Service network
models

Open Semantic Service Network (OSSN)
influences

General System Theory (GST)

General System Theory
• A theory [3] successfully applied in many fields of research
– e.g. by John Von Neumann in computing and Ed Yourdon in structured analysis and design

• Internal Relationships (R1)
– Cause-effect relations between the internal elements of a service system
– E.g., participants, to information, to resources, to legal aspects, and to pricing
– Change quality of a business process activity -> change in the cost of another related
activity

• External Relationships (R2)
– Establishing cause-effect relations between internal- and external service systems
– e.g., quality level delivered by one service depends on the quality of the other service

• Understanding Change (R3)
– Time needs to be an integral modeling element
– Network may grow by adding relationships -— randomly, but by attraction or preference
not
to certain nodes. [8]


SN and Preferential Attachment
Self-organizing system

• Hypothesis
– Highly connected services increase their
connectivity faster than less connected ones
– Preferential attachment (PA) phenomenon
– Only local information

• Preferential attribute
– e.g. price, quality, or availability


OSSN Formal Modeling


OSSN and Preferential Attachment

• Use USDL value proposition as a
preferential attachment.
– usdl:valueproposition
– Service value is judged from the perspective
of consumers as they compare services
among the alternatives.

• Let us assume
– price is the value proposition (local rule)



• Objective
– Forecast the evolution of a service network
– The market share of each service is:


• The service market
share is represented in
the figure at t = 3.

• What will happen to the
market if the conditions
are not changed*?

• According to Bass
model, the leading
service will reaches a
fixedpoint market share
according to:

*the value propositions of remain the same

SN and System Dynamics
Self-organizing system

• Explore the applicability of system
dynamics
– Using mathematical expressions to model the
relationships of SN
– Instead of looking at causes and their effects in
isolation (e.g. PA)

• The next figure
– Service systems S , S , S ,i j k

– Links illustrating internal and external
relationships


SN and System Dynamics
USDL Service system Si
+ USDL
Si KPI = Sk KPI =
+ Si KPI = Net gains Resource Limit
# services
+
+ -
OSSR + + OSSR
- KPI Gain per Service
Total Services Individual system Sk
+ Service
OSSR • Positive Feedback (+)
- Reinforcement and amplification
+
+
• Negative Feedback (-)
Counteracts perturbations and
Sj KPI = +
Sj KPI = Net gains stabilizes
# services
+ OSSR Causal links connect KPIs
USDL Service system Sj from different services’ and
within services.
a)
(’Tragedy of the Commons’
archetype )

OSSN and System Dynamics
• If the two services Si and Sj overuse the shared service Sk,
– It will become depleted and all the providers will experience
diminishing benefits

• Services Si and Sj
– To increase net gains, both providers increase the availability of
service instances
– As the number of instances increases, the margin decreases and
there is the need to increase even more the number of instances
available
– As the number of instances increases, the stress on the availability of
service Sk is so strong that the service collapses or cannot respond
anymore as needed
– At that point, service Si and Sj can no longer fully operate and the net
gain is dramatically reduced for all the parties involved as shown in
the following figure Si

Time

Conclusions
• Open semantic service networks (OSSN)
– Large scale, open, dynamic, and highly distributed
– Currently static

• General System Theory provides requirements for dynamic OSSN
– Introduces internal & external relationships between services
– Add time and information that triggers network evolution
– Requires to extend the Unified Service Description Language (USDL) model
– Requires to extend the Open Semantic Service Relationship (OSSR) model

• Implications
– Evolutionary and analytical analysis of dynamic OSSN
– Stepping stones for creating algorithms to understand service networks


References
3. Von Bertalanffy, L.: General System Theory: Foundations, Development, Applications. The
International Library of Systems Theory and Philosophy. Braziller (2003)
8. Yule, U.: A mathematical theory of evolution based on the conclusions of dr. j. c. willis. Phil. Trans.
Roy. Soc. Lond. 213(2), 21–87 (1925)
12. J. Gordijn, E. Yu, and B. van der Raadt, e-service design using i* and e3value modeling, IEEE
Software, vol. 23, pp. 26-33, 2006.
13. H. Akkermans, Z. Baida, J. Gordijn, N. Pena, A. Altuna, and I. Laresgoiti, Value webs: Using
ontologies to bundle real-world services," IEEE Intelligent Systems, vol. 19, no. 4, pp. 57--66, Jul.
2004.
14. O. Danylevych, D. Karastoyanova, and F. Leymann, Service networks modelling: An soa & bpm
standpoint, Journal of Universal Computer Science, vol. 16, no. 13, pp. 1668--1693, jul 2010.
15. V. Allee, Reconfiguring the value network," Journal of Business Strategy, vol. 21, no. 4, pp. 1-6,
2000.
16. N. Weiner and A. Weisbecker, A business model framework for the design and evaluation of
business models in the internet of services, in Proceedings of the Annual SRII Global Conference,
Washington, DC, USA, 2011, pp. 21-33.
17. R. C. Basole and W. B. Rouse, Complexity of service value networks: Conceptualization and
empirical investigation, IBM Systems Journal, vol. 47, no. 1, pp. 53-70, 2008.


References
• [CPL+13] Cardoso, J.; Pedrinaci, C. and Leenheer, P. D Open Semantic Service Networks:
Modeling and Analysis. In 4th International Conference on Exploring Service Science (IESS
1.3), pages 141-154, Springer, LNBIP, Porto, Portugal, 2013.

• [Car13] Cardoso, J. Modeling Service Relationships for Service Networks. In 4th International
Conference on Exploring Service Science (IESS 1.3), pages 114-128, Springer, LNBIP, Porto,
Portugal, 2013.

• [CM12] Cardoso, J. and Miller, J. A Internet-Based Self-Services: from Analysis and Design to
Deployment. In The 2012 IEEE International Conference on Services Economics (SE 2012),
IEEE Computer Society, Hawaii, USA, 2012.

• [CPL+12] Cardoso, J.; Pedrinaci, C.; Leidig, T.; Rupino, P. and Leenheer, P. D Open semantic
service networks. In The International Symposium on Services Science (ISSS 2012), pages 1-15,
Leipzig, Germany, 2012.

• [CBM+10] Cardoso, J.; Barros, A.; May, N. and Kylau, U. Towards a Unified Service Description
Language for the Internet of Services: Requirements and First Developments. In IEEE
International Conference on Services Computing, IEEE Computer Society Press, Florida, USA,
2010.


Suggestions & Questions?


Open Semantic Service Networks: Modeling and Analysis

Recommended

Recommended

More Related Content

Similar to Open Semantic Service Networks: Modeling and Analysis

Similar to Open Semantic Service Networks: Modeling and Analysis (20)

More from Jorge Cardoso

More from Jorge Cardoso (17)

Recently uploaded

Recently uploaded (20)

Open Semantic Service Networks: Modeling and Analysis