CoOL: A Context Ontology Language to Enable Contextual Interoperability Thomas Strang, Claudia Linnhoff-Popien, and Korbinian Frank German Aerospace Centor (DLR). Oberpfaffenhofen, Germany Ludwig-Maximilians-University (LMU), Munich, Germany Presented by Sangkeun Lee IDS Lab.

Copyright  2008 by CEBT Introduction  The pervasive computing trend is driving a need for context- aware service architectures involved in a service interaction To reduce the amount of required user actions Various actors – E.g. any user, any service provider, environment, or third parties  A key to context information in context-aware system is a Well designed model to describe contextual facts and contextual interrelationships Previous works lack formality  The context modeling approach in this paper tries to close the formality gap by using Ontologies Another example: CONON (Context Ontology) IDS Lab. Seminar - 2Center for E-Business Technology

Copyright  2008 by CEBT What is Context?  Definition of Context Information “A context information is any information which can be used to characterize the state of an entity concerning a specific aspect” “An entity is a person a place or in general an object” “An aspect is a classification, symbol or value-range, whose subsets are a superset of all reachable states” IDS Lab. Seminar - 3Center for E-Business Technology Reference: “Trends in Mobile Computing From Mobile Phone to Context-Aware Service Platform” by Thomas Strang

Copyright  2008 by CEBT What is Context? (cont’d)  Definition of Context “A context is the set of all context information characterizing the entities relevant for a specific task in their relevant aspects” “An entity is relevant for a specific task, if its state is characterized at least concerning one relevant aspect” “An aspect is relevant, if the state with respect to this aspect is accessed during a specific task or the state has any kind of influence on the task” IDS Lab. Seminar - 4Center for E-Business Technology Reference: “Trends in Mobile Computing From Mobile Phone to Context-Aware Service Platform” by Thomas Strang

Copyright  2008 by CEBT Context-awareness  Definition of Context Awareness: “A system is context aware if it uses any kind of context information before or during service provisioning or service usage”  Two main benefits from Context Awareness: Adaptation of services to changes in environment reduces amount of interaction with user – Improvement of UI (particularly on small mobile devices) IDS Lab. Seminar - 5Center for E-Business Technology Reference: “Trends in Mobile Computing From Mobile Phone to Context-Aware Service Platform” by Thomas Strang

Copyright  2008 by CEBT Ontologies and the Context Ontology Language  Challenge to describe contextual facts and interrelationships in a precise and traceable manner  “print document on printer near to me” It is required to have a precise definition of terms used in the task, particularly what “near” means to “me” It is highly desirable that each participating party in a service interaction share the same interpretation of the meaning “behind” it – Shared understanding  Ontologies May be stored at different places and created by different authors, which offers flexibility and extensibility IDS Lab. Seminar - 6Center for E-Business Technology

Copyright  2008 by CEBT Context Ontology Language (CoOL)  CoOL Core OWL and DAML+OIL F-Logic  CoOL Integration A collection of schema and protocol extensions as well as common subcontepts, enabling the use of CoOL Core in several service frameworks (e.g Web Service) Out of focus of this paper  Having a projection of the model in multiple ontology languages enables that Developer may use any of languages which seems to be adequate – Using OWL because of wide range of available tools – Using F-logic because of its rule based extensibility IDS Lab. Seminar - 7Center for E-Business Technology

Copyright  2008 by CEBT ASC Model  Aspect-Scale-Context (ASC) model Named after the core concepts Each aspect aggregate one or more scales Each scale aggregates one or more context information hasAspect, hasScale, constructedBy IDS Lab. Seminar - 8Center for E-Business Technology

Copyright  2008 by CEBT ASC Model Examples IDS Lab. Seminar - 9Center for E-Business Technology Reference: “Ubiquitous Computing :Context and Context- Awareness”, University of Innsbruck, Lecture slide from SS 2005 Another Example: SpartialDistanceAspect - MeterScale,KilometerScale – 10, 20 Fahrenheit's temperature scaleCelsius temperature scale Specific Values

Copyright  2008 by CEBT Operations  IntraOperation Mapping function from one scale to at least one other of the already existing scales of the same aspect  InterOperation Scales which require access to scales of one or more other aspects can be defined using InterOperations E.g. – “KilometerPerHourScale” of a “SpeedAspect” can be defined by using an InterOperation with two Parameter, delta_s and delta_t where delta_s is from an aspect “SpatialDistanceAspect” delta_t is from an aspect “DurationAspect”  MetricOperation Compare two context information instances IDS Lab. Seminar - 10Center for E-Business Technology

Copyright  2008 by CEBT Transfer Model  ASC model may be used as transfer model to employ the knowledge expressed in other context models  Example: Henricksen Context extension to the Object-Role Modeling approach The basic modeling concept in ORM is fact Henricksen extended ORM to allow fact types to be categorized either as static or dynamic (profiled, sensed, derived)  Using ASC Model Facts can be modeled as “context information” Classification can be mapped by introducing a “quality aspect” consisting the element {static, dynamic profiled, dynamic sensed, dynamic derived} dependOn relation can be expressed using Intra/InterOperations IDS Lab. Seminar - 11Center for E-Business Technology

Copyright  2008 by CEBT Relation to DAML-S  DAML-S : ontology of services ServiceProfile, ServiceModel, and ServiceGrounding Extension: ServiceContext – May serve as a formal description of a service’s contextual interoperability by providing a comprehensive but extensible model based on the ASC model IDS Lab. Seminar - 12Center for E-Business Technology

Copyright  2008 by CEBT Motivation: MNM Service Model and the Context Extension IDS Lab. Seminar - 13Center for E-Business Technology

Copyright  2008 by CEBT System Architecture IDS Lab. Seminar - 14Center for E-Business Technology  The authors focus on the context provider domain as introduced in the previous page

Copyright  2008 by CEBT Discussion & Conclusions  Discussion ASC model – The authors gives us a different point of view (compare to CONON) – What’s weak points and strong points? It is interesting the authors classified actors into – Context Providers, Service Providers, Customers – Who can be Context Providers?  Conclusions The authors introduced ASC model as a base model to express how some context information can be used to characterize the state of an entity concerning a specific aspect ASC model fits into a general purpose service model – Context Extension : Making any service interaction based on that model context- aware ASC model as transfer model IDS Lab. Seminar - 15Center for E-Business Technology