1) The document proposes a framework called MACOCO to enable online awareness of changes in the service market for both service providers and consumers. 2) In MACOCO, service providers and consumers are represented as active software agents that can negotiate on their behalf. Consumers can express requirements using abstract specifications that are concretized at runtime based on available market knowledge. 3) The framework aims to make providers collectively aware of market demands and opportunities, and keep consumers continuously aware of needed adaptations to support automatic maintenance of service-based systems.

1. Market-­‐awareness
in
Service-­‐based
Systems
Romina Torres, Hernan Astudillo Nelly Bencomo
Universidad Técnica Federico Santa María, Chile INRIA Paris - Rocquencourt, France
{romina, hernan}@inf.utfsm.cl nelly@acm.org
Abstract
In
ac9on
Service providers and consumers exist in a service market that is constantly At design time
changing. While service providers continuously improve their quality of services
(QoS), service consumers can update their specifications according to what the R
market is offering. In this work, we propose a framework to enable online awareness
Send email with the location of
of changes in the service market to both, consumers and providers, by representing
user as fast as possible
them as active software agents. Our approach dictates that abstract specifications of
the QoS are defined during design time. At runtime, consumer agents concretize QoS
specifications according to the available market knowledge. Services agents are L(KT)
collectively aware of themselves and of the consumers’ requests. Moreover, these response time =
agents can create and maintain virtual organizations that create or maintain aligned {fast, average, slow}
the architecture of service-based systems with the market. 2
Problem
S*
S*
S , K R Service of category {send,
Service of category {send,
email} with at least a fast
Service of category What does it mean fast Send emails from the email} with at least a fast
response time
12100 with at least a in services capable to application as fast as response time
response time less than send email? possible
1
10 milliseconds
3 2 1 3
At runtime is valid only if K has not changed considerably since the
specification S was defined
KT+z
KT+y To maintain R satisfied:
KT+x
KT+w
KT+v KT+v
KT
2+3
…
At runtime
KT+z
Providers:
- are under an inherent competition with functionally-equivalent providers
- are passive entities waiting to be discovered
- are missing business opportunities
4
Consumers: periodically
- QoS specifications depend on what the market is currently offering
- Are too busy: trying to understand the market, searching candidates, composing Contracts between consumers and providers are subscribed to the monitoring process of
solutions, verifying their compliance and determining the needed adaptations the adaptation recommender system (Adaptive).
Time to time Adaptive monitors the contracts, analyze them (in order to determine if the
Proposal contracts have been violated recurrently) and ask to the market a new configuration if
an adaptation is needed.
We propose to make service consumers and providers market-aware in order to The service market is also monitored. If there is enough evidence the market has
achieve automatic adaptive maintenance of service-based systems. changed, then a new knowledge domain is generated and then all contracts are
remapped into concrete specifications.
CONCLUSIONS
Service providers are collectively aware of the current demands of the market, other
competitors and even potential partners to provide services as virtual organizations.
Service consumers are continuously aware of the adaptations needed to automatically
perform adaptive maintenance.
without MACOCO
Related
Publica9ons
[1]- Requirements-Aware Systems A research agenda for RE for self-adaptive systems, Pete Sawyer, Nelly Bencomo,
Jon Whittle, Emmanuel Letier, Anthony Finkelstein, International Requirements Engineering Conference, RE 2010, Sydney,
Australia, September, 2010
[2]- Web service compositions which emerge from virtual organizations with fair agreements (best student paper),
Romina Torres, Denise Rivera, Hernan Astudillo, KES Agent and Multi-Agent Systems. Technologies and Applications.
Dubrovnik, Croatia, June 2012.
[3]- Toward open-world software: Issue and challenges, Luciano Baresi, Elizabeth Di Nitto, and Carlo Ghezzi.
Computer, vol. 39, no. 10, pp. 36–43, Oct. 2006..
[4]- Mitigating the obsolescence of quality-specification models in service-based systems, Romina Torres, Nelly
Bencomo, Hernan Astudillo, in Model-Driven Requirements Engineering Workshop (MoDRE), sept. 2012.
with MACOCO [5]- From virtual organizations to self-organizing web service compositions, Romina Torres, Denise Rivera, and
Hernan Astudillo, in Proceedings of the XXIX International Conference of the Chilean Computer Science Society, ser. SCCC
’11. IEEE Computer Society, 2011.
[6]- Four dark corners of requirements engineering, Pamela Zave and Michael Jackson ACM Trans. Softw. Eng.
Methodol., vol. 6, no. 1, pp. 1–30, Jan. 1997.
Market-awareness = MACOCO + Language to mitigate the obsolescence of the quality
specifications
- Consumers and providers are represented as active software agents who negotiate on Acknowledgements
their behalf. They have a common environment represented by the Blackboard.
This work was partially funded by FONDEF (grant D09i1171), UTFSM DGIP 241167, BASAL
- Consumers avoid the obsolescence of their specifications by expressing their requirements FB0821(FB.02PG.11), the EU Marie Curie Project Requirements@runtime and the EU
using abstract specifications. These abstract specifications are concretized at runtime. Connect project.