Structure ARPA I3

It is about a generic architecture of the solutions of mediation conceived by the ARPA (Advanced Research Projects Agency) of the department of the American défence. This baptized architecture I3 (Intelligent Integration off Information) is a development of that proposed by Wiederhold in which the term “mediator” is a generic term very indicating component of a solution of mediation. For Wiederhold, the term “mediator” is on the other hand employed in the direction of a component responsible for the integration of the data, generating high level information, mainly by summarizing the whole of the furnished informations by various sources.

I3 architecture is divided into five classes of service; services of coordination, services of management, services of integration and semantic transformation (SIT), services of functional extensions and services of adaptation. These services are not orthogonal, the diagram of ARPA architecture explains the functional dependences.

Services of coordination (C)

The services of coordination include/understand the whole of the management tools of the configuration of a solution of mediation is:

C1 Service of selection and invocation (broker)

This service receives the requests of the users directly. This one does not carry out any operation of decomposition of the request or translation. Its only role consists in locating using metadata, of ontologies and repertories, the service most suited to solve the request. Then, he delegates the task of resolution of the request to the service which he found. Certain authors use the term of “router” for this service type.

The services used by the brokers are the services of discovered resources (M1) and the services of interpretation and execution of the moulds (M3). They also use the services of the family S and F.

the entries are:

Request of the user
Answer of a service I3
Ontology and metadata describing the model of the user (ontology used for the request, desired service)

the exits are:

Answer turned over to the user

C2 Service of management of the configuration (facilitator)

A facilitator is a broker offering more services. It is able to carry out translations making it possible to redirect the request towards a service using another syntax. It can also break up a request into under-requests and schedule and distribute those to the various services which it will have located beforehand. To finish, it can combine (to integrate) the various results in a coherent answer. The services used by the facilitateurs are the services of discovered resources (M1) and the services of interpretation and execution of the moulds (M3). They also use the services of the family S and F.

the entries are:

Request of the user
Response of I3 services to the under-requests
Ontology and metadata describing the model of the user (ontology used for the request, desired service)

the exits are:

integrated Answer turned over to the user
List of the various entries of control (flow of control) sent to the services used

C3 Service of judicial law-making of configuration (Matchmaker)

This service is described like ready to generate a mediator. It generates the configuration necessary to provide the desired service. This configuration defines the services used, the bonds of communication used, the translations necessary and the checking routines necessary for séquencer the request. This service thus does not solve the request but turns over to the user a solution of resolution of the request, that is to say the whole of the stages which the user must carry out to solve his request.

The services used by the matchmakers are the services of discovered resources (M1) and the services on the processes of configuration (m2). They also use the services of the family S and F.

the entries are: Request of the user

Ontology and metadata describing the model of the user (ontology used for the request, desired service)

the exits are:

Solution of connection and configuration of the services being able to deliver a solution.

C4 Interface ad hoc application

Hold-all category where one finds any interface offering of the services of mediation directly usable by the user, and not being able to be described by C1, C2 or C3.

Services of management (M)

It is about a collection of services allowing the invocation and the scheduling of the I3 services. They also make it possible to configure the various services so as to treat a certain request.

M1. Services of discovered resources

M1.A white pages, intelligent yellow pages and yellow pages

The white pages are simplest, they do nothing but record and désenregistrer the resources and activate or decontaminate those; they make it possible to find a resource knowing only its name. The yellow pages make it possible to find resources according to the desired service. The intelligent yellow pages carry out inference to deduce the service wished according to a request from service perfectly syntactically and/or not being semantically standardized.

M1.B Service of navigation (navigators)

The navigators allow users to sail in the metadata and the diagram of a particular data source. They also make it possible another service to reach and sail in the metadata and diagram of a data source. Those inter alia are used by the adapters.

M1.C with M1.E Service of explanation and assistance of the services, process and tools

M1.C Service of explanation of the services and tools
M1.D Service of explanation of the processes
M1.E Service of assistance to the creation of requests

These services assist the user or the services of coordination in the use of the system and the creation of requests.

M2 Services of configuration

M2.A Service of selection of services
M2.B Service of selection of tools and information sources
M2.C Service of creation of moulds (templates)
M2.D Monitoring service of process

These services are used by the services of coordination when they build a solution of configuration. The selector of services makes it possible to find the services making it possible to carry out a particular task. The selector of tools and information sources makes it possible to find the suitable information sources and tools to carry out a particular task. The service of creation of moulds is used to determine how to combine the various tools and information sources to generate a mould (elements of configuration). The controller of process allows the construction of a mould (the mould is regarded here as being achievable code).

M3 Services of interpretation and execution of moulds

M3.A syntactic Abstracting service (parser) and generation of configurations
M3.B Service of scheduling of process
M3.C Service of management of the processes and the data

These services make it possible to carry out a mould (template configuration). The parser generates a configuration starting from a mould. The director of process manages the distribution and the control of the configuration on several processes whereas the manager of the processes and the data generates control concerning a particular process and maintains a bank of local information.

Services of integration and semantic transformation (S)

These services make it possible to manage and handle ontologies, contexts and diagrams. In the first case, the entry consists of a source or several information sources and the exit in an integration or a transformation of this information. In the second case, the entry consists of a software component and the exit is the component one reconfigured.

S1 Services of integration of diagrams

These services allow the integration of diagrams and knowledge starting from multiple sources.

S1.A Service translation of ontologies and vocabulary

This service makes it possible to generate an ontology being the intersection of several ontologies or to convert a term of an ontology source in the term corresponding of the ontology of destination.

S1.B Service translation of sights

This service makes it possible to establish the correspondences between a local diagram and a total diagram.

S1.C Service of integration of sights

This service makes it possible to integrate a local diagram into a total diagram.

S2 Services of Integration of information

S2.A and S2.B Service of reorganization, abstraction and aggregation

S2.A Service of reorganization of the data
S2.B Service of abstraction and aggregation

These services make it possible to create a synthesis of information of several sources. The services of creation of summaries and abstractions make it possible to condense information for decision making.

S2.C Service of mapping of objects

This service makes it possible objects of distinct sources to be regarded as being the same one within a common diagram (responsible for the operations of semantic bringing together and reconciliation or unification of contexts).

S2.D Service of transformation of contexts

This service typically allows the translation of a context of an ontology another and a format of context to another.

S3 Services of integration of the processes

S3.A Service of decomposition of request Allows to break up a request into under-requests intended for several services. S3.B Service of integration of the results Allows to combine the various results of the various under-requests in an integrated and coherent answer. S4. Services of physical integration These services make it possible to carry out integration and the connection between components on the levels system and syntactic.

Services of functional extensions (F)

F1 Services active

F1.A Service of triggering
F1.B Service of monitoring
F1.C Service of propagation of updates
F1.D Operation practical of rules
F1.E Service of resolution of the conflicts between rules

These services make it possible to carry out event-driven procedures like the monitoring of events or the respect of constraints of integrity.

F2 Services of inference

These services allow the operations requiring a complex reasoning starting from rules (reasoning of the expert system type).

F3 Services of management multi-states

These services allow the management of the change, including the evolution of the diagram, the data, of the versions, the replication of the data and the accesses hypothetical to the data.

Services of adaptation (W)

This service is that which the adapters must provide. The functional need to which an adapter must answer is to standardize the syntax and the semantics of a local source data by converting them with the format of the mediation. This service offers a solution of information circulation, making it possible to preserve the local autonomy of the data sources.

W1 Services of adaptation of the communications

W1.A Service of adaptation of the interfaces of calls

Allows syntactic and semantic conversion interfaces of incoming calls two programs.

W1.B Service of management of events

Allows the management of the traffic of the events between an information source and an incompatible service moreover high level.

W1.C Service of adaptation of the calls of methods and functions

Allows the conversion of the calls of methods and functions between an information source and an incompatible service moreover high level.

W2 Services of reorganization of the data

W2.A Conversion of the formats

Allows diagrammatic and syntactic conversion data the format of the mediation.

W2.B Reorganization of the metadata

The conversion of the metadata allows the format of the mediation.

Behavioral W3 Services of adaptation

W3.A Service of modification of the application

The modification of the semantics (behavior) of a program allows while modifying, for example, of calculations.

W3.B Service of modification of protocol

Allows the modification of a protocol (communication, management of competition, etc).

W3.C Service translation of language

The translation of a data manipulation language allows another. For example, of SQL with OQL.

Random links: