Contracts for defining QOS levels in a Multichannel Adaptive Information System Moreno Callea, Luca Campagna Mariagrazia Fugini, Pierluigi Plebani Dip. Elettronica ed Informazione Politecnico di Milano – Italy MOBIS 2004 Conference - September 15th, Oslo, Norway

Sept. 15th 2004MOBIS Oslo, Norway2 / 18 Outline Multichannel adaptive information systems Quality of service model WSLA extensions Prototype Concluding remarks

Sept. 15th 2004MOBIS Oslo, Norway3 / 18 Service Oriented Architecture publishfind invoke Service Requestor Service Provider Service Directory (broker) Transmission medium

Sept. 15th 2004MOBIS Oslo, Norway4 / 18 Multichannel Information Systems Today the services are usually provided by a single-channel (Web) We want to provide services through different channels: Smartphone PDA …

Sept. 15th 2004MOBIS Oslo, Norway5 / 18 Multichannel adaptive Information Systems The client could change the channel, during service exploitation The system could adapt the service provisioning by changing the provisioning channel according to quality of service (QoS) parameters

Sept. 15th 2004MOBIS Oslo, Norway6 / 18 MAIS Project Italian research project Aims at studying a set of models and methodologies which allow service provisioning through different channels Web Site:

Sept. 15th 2004MOBIS Oslo, Norway7 / 18 Quality of Service adaptation strategies both the service and provider side depend on the QoS definition channel deeply affects the values of the QoS parameters on the provider side so the user can perceive different values according to the active channel In a service oriented environment we have to consider all the involved actors independently

Sept. 15th 2004MOBIS Oslo, Norway8 / 18 Our model Composed by: A system model: objects and actors A set of roles and rules association of quality information to objects relationships among them Quality information expressed by: Quality parameters Quality sets

Sept. 15th 2004MOBIS Oslo, Norway9 / 18 Quality Model

Sept. 15th 2004MOBIS Oslo, Norway10 / 18 Quality of Experience Represents the quality perceived by the user Composed by the same quality parameters belonging to the QoS where the values are affected by the QoN, and QoD Quality rules QoS QoNQoD QoE

Sept. 15th 2004MOBIS Oslo, Norway11 / 18 Contracts Service provider and service user must agree on the quality parameters Contract is in charge to define this agreement defining: Roles Quality parameters Responsibilities

Sept. 15th 2004MOBIS Oslo, Norway12 / 18 Main existing specifications QML (Quality of Service Modeling Language) uses an OOP approach to define the QoS parameters XQOS (XML Based QoS Specification Language) Xml-based, Related to multimedia systems Define relationship between users and provider through the channel WSLA (Web Service Level Agreement) Xml-based, Close related to the Web Service environment

Sept. 15th 2004MOBIS Oslo, Norway13 / 18 WSLA

Sept. 15th 2004MOBIS Oslo, Norway14 / 18 WSLA extensions New attributes to specify the pairs Concept defined in QML is adopted Ordering Data Type: Numeric, Set, Enum

Sept. 15th 2004MOBIS Oslo, Norway15 / 18 Guarantee terms Service Level Objective: For each Attributes: Name, Device, Network interface, Order Data timeliness Admissible range for each quality parameters Action Guarantee: Action performed in case of unfulfillment Who violates

Sept. 15th 2004MOBIS Oslo, Norway16 / 18 Prototype architecture

Sept. 15th 2004MOBIS Oslo, Norway17 / 18 Prototype architecture

Sept. 15th 2004MOBIS Oslo, Norway18 / 18 Conclusions This work presents a framework to define the quality information in a multichannel information system It is based on a model where all the involved actors can separately state the quality information for the controlled object A monitoring system is required