demo summer soc-28062012
TRANSCRIPT
Summer SOCJuly 2nd – July 7th
Aniketos platform:Design of a trustworthy composite
service
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Summer SOC 2012
A service provider wants to offer a service that takes ininput the geographical position of a user and shows in awebpage a set of information: A map showing the position Weather information Point of interests in the surroundings
The service provider wants the service to be trustworthy,so he asks the service designer to exploit the tools madeavailable through the Aniketos platform
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Reference scenario for the demo
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The trustworthiness value is evaluated by theTrustworthiness Prediction module and is a combinationof: Cognitive trust of the user, based on the service and service
provider reputation. Non-cognitive trust, based on objective and measurable properties
of the service such as QoS attributes (reliability, performance,availability)
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About trustworthiness in Aniketos…
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Service Composition Framework (SCF)
The SCF is a design timemodule available in theAniketos environmentallowing a service designerto build executablecomposition plans
To use the framework theservice designer must beauthenticated
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SCF: get started with BPMNmodelling
Onceauthenticated,the servicedesigner canstart the BPMNmodelling
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BPMN model of InfoService
From the description of the service in terms offunctionality, the service designer decides to use differentatomic services and compose them according to theBPMN drafted in the SCF editor
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The service designer is in charge of designing acomposite service with a specific requirement ontrusthworthiness value
The trustworthiness requirement is expressed as aconsumer policy written in ConSpec grammar
The file location is included in an extensionElements tag inthe xml representing the BPMN
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BMPN annotated with trustworthinessrequirement
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An excerpt of the resulting xml for the annotated BPMN isshown below:
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Annotated BPMN
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To make the composition plans the SCF has to bind realweb services to the service tasks in the BPMN
The binding process entails: Service discovery using the ServiceType as search filter
The SCF shows the operations offered by the web services matchingthe request based on the ServiceType
Selection of the specific operation the service designer wants touse in order to compose the InfoService If the same operation is offered by different atomic services the
service designer will see just one operation
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Service discovery and selection ofthe service operation
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Discovery and selection: GeoCodingexample (1/2)
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and selects getCoordinates ( )
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Discovery and selection: GeoCodingexample (2/2)
The service designer discovers operations offered by GeoCoding typeservices ( )
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The service designer isn’t aware of how many web services offerthat operation, it’s the SCF which will bind the different servicesto the service task when making composition plans
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Creation of composition plans
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Once the service designer has selected an operation foreach service task the SCF is ready to create thecomposition plans
When the service designer clicks on “Create compositionplans” button, the SCF shows a set of functionally validcomposition plans
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The SCF has created 12 compositionplans: this is explained by the number of web
services offering the same operation: Geocoding type: bound to 2 web services PointOfInterest type: bound to 3 web services WeatherForecast type: bound to 1 web
services Map type: bound to 2 web services WebPageInfoCollector type: bound to 1 web
services
Thus the number of composition plansis 2 X 3 X 1 X 2 X 1 = 12
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Composition plans created by the SCF
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The composition plans ensure functionality but do notconsider the trustworthiness requirement
The composition plans have to be checked against therequirements specified for the trustworthiness value
This check is performed by the Secure CompositionPlanner Module which receives the composition plansfrom the SCF and returns those ones that fulfill thetrustworthiness requirement
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Selection of trustworthy compositionplans
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The SCPM invokes the Trustworthiness prediction moduleto evaluate the trustworthiness value for the set ofcomposition plans received from the SCF
The trustworthiness value of the composite service isevaluated using the weakest link principle The Trustworthiness module evaluates the trustworthiness value
for each service taking part in the composition The lowest value is returned as the trustworthiness value of the
composite service
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Trustworthiness prediction forcomposite services
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When the service designer clickson “Verify All” button the SCPMselects the composition plans thatfulfils the trustworthinessrequirement
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Trustworthy composite services
In order to visualize theTrustworthiness value of thecomposition plans the servicedesigner selects “Order By”Trustworthiness and clicks on“Order/Rank” button
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Last steps: upload and deploy
The service designer selects one ofthe trustworthy composition plans andcan Upload the BPMN to an Activiti
Engine Deploy it to a web application
server
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