m. adorni, f. arcelli, d. ardagna, l. baresi, c. batini, c. cappiello, m. comerio, m. comuzzi, f. de...
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M. Adorni, F. Arcelli, D. Ardagna, L. Baresi, C. Batini, C. Cappiello, M. Comerio, M. Comuzzi, F. De Paoli, C. Francalanci, S.Grega, P. Losi, A.Maurino, S. Modafferi, B.
Pernici, C. Raibulet, F. Tisato
The MAIS approach to web service designThe MAIS approach to web service design
Porto 13 June 2005
Andrea MaurinoAndrea Maurino
Università di Milano BicoccaUniversità di Milano Bicocca
maurino@disco.unimib.itmaurino@disco.unimib.it
2The MAIS approach to web service design
OutlineOutline
The MAIS Project
The MAIS Methodological Framework • General view
Service Specification and Compatibility Analysis Broker-Provider Negotiation and Dynamic Evaluation of
Management Costs Process Partitioning Optimal Service Selection and Quality Renegotiation Implementation Guidelines for a QoS-Oriented Reflective
Architecture
Conclusions and future work
4The MAIS approach to web service design
The MAIS ProjectThe MAIS Project
Develop methods, models, and architectures for multichannel adaptive information systems
Multichannel• Service provisioning: web, e-mail, sms, client-server
• Mobile information systems
Heterogeneity, dynamic evolution of channels• Device characteristics
• Network connections
Adaptation to context• User model
• Service provisioning
• Channel of invocation, QoS
5The MAIS approach to web service design
Research focResearch focusus
Adaptive orchestration of e-services Reflexive architecture for context-aware services Design of web Services with QoS
Adaptive networks Low power consumption processors
Methods and tools for multichannel interface design and integration
Application areas: e-learning, tourism, emergency teams
7The MAIS approach to web service design
The MAIS methodological frameworkThe MAIS methodological framework
4 Methodological steps
Requirements Analysis
• elicit, validate and negotiate web service requirements
• Multichannel, QoS
Design
• model services with MAIS-UML
Deploy
• Network infrastructure
Run time
• adaptive and context-aware use of web services
8The MAIS approach to web service design
FrameworkFramework
Analysis
Design
Deployment
Runtime
Service specification and compatibility analysis
Broker-provider negotiation and dynamic evaluation of management costs
Process Partitioning
Optimal service selection and quality renegotiation
Broker-provider negotiation and dynamic evaluation of management costs
Input/output
Interdependence
Domain Req.QoS Req.User Req.Actual ServicesArchitectural Req. UML Diagrams
QoS Req.User Req.PriceArchitectural Req.Budget
Architectural Configuration
Domain and QoS Req.Global/Local ConstraintsPriceMAIS-Registry
Process Description
9The MAIS approach to web service design
Service Specification and compatibility analysisService Specification and compatibility analysis
Analysis, (re)-design of web service
• Use of MAIS QoS, Services and Channel Ontology
3 sub-phases:
functional service modelling,
• Model requirements thanks UML
• Logical and operational structure of Web Services
high-level redesign
• Augment existing schema with QoS dimension (from the MAIS QoS ontology)
• Modelled with MAIS-UML profile
• Metrics QoS dimensions have a (Bk)) quality level
10The MAIS approach to web service design
Service Specification and compatibility analysisService Specification and compatibility analysis
Context adaptation
• Verification of quality values of QoS requirements and Quality thresholds
Comparison between Bk of each QoS and ideal level
request by user
QoS tree
Simple Additive Weighting technique
• Weights and composition rules to each node
11The MAIS approach to web service design
Process PartitioningProcess Partitioning
New deployment strategies for MobIS Goals:
• improve the independency among actors
• Reduce interaction and knowledge sharing
Solution: decompose a unique process into a set of sub process• Automatic partitioning rules
• Based on graph transformation systems
Input: MAIS-UML (translated into MAIS-BPEL), network topology
Output: set of MAIS-BPEL Some formal and empirical result on the correct
behaviour of sub process
12The MAIS approach to web service design
Optimal Service Selection and Quality RenegotiationOptimal Service Selection and Quality Renegotiation
Goal: select from registry a set of services • functional equivalent service
Optimization problem with two difference approach Select at run time the best candidate service which supports
the execution of a running high level activity. (local level)• Service can be selected if its price is lower than a given threshold
Identiy the set of candidate services which satisfy end-user preferences for an entire application (global level)• the total price has to be less than 2$.
Service composition with QoS modelled as a mixed integer linear programming problem • NP-hard !!! Multiple Choice Multiple Dimension Knapsack problem
• We use CPLEX, a state of the art commercial solver, which implements a branch and cut technique
13The MAIS approach to web service design
Broker-Provider Negotiation and Dynamic Evaluation of Broker-Provider Negotiation and Dynamic Evaluation of Management CostsManagement Costs
Broker between provider and users Conflicting Goals
• Maximize the satisfaction of user requirements
• Achieve maximum possible returns from its brokering role
Broker is paid each time a service is supplied by user Broker can increase the QoS offered by provider Preliminary phase
• set the value of a triple <pij,percij,qij>
• pij :price paid by the user for the service,
• percij :is the percentage on the price due by the service
provider to the broker (0 and 1)
• qij is the aggregate value of QoS offered to user (0 ≤ qi j≤ 1).
14The MAIS approach to web service design
Broker-Provider Negotiation and Dynamic Evaluation of Broker-Provider Negotiation and Dynamic Evaluation of Management CostsManagement Costs
Negotiation processes is realized by means of • Negotiation Protocol:
• bilateral bargaining protocol;
• Negotiation Objectives: • typical multiattribute problem: negotiation of a triple of attributes
• Decision Model: • trade-off based strategy
Utility function V • evaluate how much an offer is worth to a participant
Increase QoS level an extra cost c*(qij),
• provide the service to the customer at a higher price p*(qij)
Modify selection of web services in case of cooperative process
Even in the design phase
15The MAIS approach to web service design
Implementation Guidelines for a QoS-Oriented Reflective Implementation Guidelines for a QoS-Oriented Reflective ArchitectureArchitecture
Architectural reflection introduces a reflective layer
• applications can observe and control at execution time non-functional features of the system components,
• supporting adaptability.
A reflective layer is causally connected to the physical layer.
Components and QoS cannot be defied in absolute way
• domain-dependent QoS like “low”, “medium”, “high”
Definition of QoS extension pattern
16The MAIS approach to web service design
Implementation Guidelines for a QoS-Oriented Reflective Implementation Guidelines for a QoS-Oriented Reflective ArchitectureArchitecture
R_Object
getQoS()setQoS()
QoSQuantitativeQoSQualitative
QoS
name : StringunitOfMeasure : String
QoSValue
QoSValueSet
1
1
1
1
1
1..*
1
1..*
1
1
+actualValue
1
1R_ElementalR_Aggregate 1 0..*1 0..*
QoSStrategy
mapUp()mapDown()
1
1
1
1
R_Object expose measurable QoS values
• Controlled/observed
• Model high-level/domain-dependent abstraction
R_aggregate casually connected to QoSStrategy to set of QoS
QoSStrategy
• How QoS is obtained/mapped
17The MAIS approach to web service design
ConclusionConclusion
Propose of a methodological framework
• From Analysis to run time execution
• Fusion of several contributions
Future works
Evolution of each component according to the specific research problem
Extension of our proposal to include MAIS results for the front-end
• Integration
• Validation
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