applications

Two application contexts motivate and spur our work. The first motivating context is transformation system engineering. It has been reinforced recently by the "semantic web" framework in which our work can find a natural place.

Technologies for the semantic web

Internet technologies support organisations in accessing and sharing knowledge, often difficult to access in a documentary form. However, these technologies quickly reach their limits: web site organisation is expensive and full-text search inefficient. Content-based information search is becoming a necessity. Content representation will enable computers to manipulate knowledge on a more formal ground and to carry out similarity or generality search. Knowledge representation formalisms are good candidates for expressing content.

The vision of a "semantic web" [Berners-Lee 2001] complements the web, with formal knowledge representation spanning across sites. In the context where web documents are formally annotated, it becomes necessary to import and manipulate annotations according to their semantics and their use. Taking advantage of this semantic web will require the manipulation of various knowledge representation formats. Exmo concerns are thus central to the semantic web implementation. Our work aims at enhancing content understanding, including the intelligibility of communicated knowledge and formal knowledge transformations.

The semantic web idea is essentially based on the notion of ontology (that can be quickly described as a logic theory). Even after the emergence of standard languages like OWL, it is still be necessary to import and exchange ontologies in such a way that the semantics of their representation language is taken care of. We work on finding the correspondences between various knowledge representation languages and ontologies (see Ontology matching) in order to take advantage of them in ontology merging and bridging or message translation (see Semantic interoperability). Bringing solutions to this problem is part of the ambition of Exmo.

In addition, Exmo also considers more specific uses of semantic web technologies in various contexts that can benefit from them such as semantic peer-to-peer systems [Atencia 2011a], social semantic networks [Jung 2007a], ambient intelligence [Euzenat 2008c], smart cities and mobile applications [Rosoiu 2015a]. In short, we would like to bring the semantic web to everyone's pocket.

Transformation system engineering

Computerisation and networking lead organisations to exchange information in machine-readable form. E-commerce generates a continuous flow of such documents. As transmitted information is neither addressed nor adapted to all the members of the organisation, it is necessary to transform document structure and content. Similarly, web sites are generated from databases or primary sources and e-commerce documents are applied various transformations before goods are shipped. Additionally, the Object Management Group Model-Driven Architecture (MDA) considers the future of software development as a composition of transformations from (platform independent) domain models to other (platform dependent) models in function of platform description models. This is considering any implementation as adaptation.

Interoperability requirements have led to the definition of the structured document representation language XML which helps handling the syntax of documents straightforwardly. Other languages such as XSLT or Omnimark, enable the implementation of standalone transformations.

However, this view of transformations is only partial and local. It seems unavoidable that, in the future, we will have to deal with complex transformation flows automating the combination of transformations, some of which come from external sources. This will require the global understanding of the behaviour of the flow of transformations. This calls for real "transformation system engineering" which should address the following issues:

• the lack of global consideration of transformations: they are processed in relation with other transformations, e.g., Transmorpher or XProc;
• the need to consider properties of transformations and especially their semantic properties: this will require the semantic analysis of transformations;
• the design of transformation flows from external resources (as it is in software engineering): this will require the ability to consider the properties of imported transformations.

Figure 1 displays an organisation in which (human and software) agents collaborate. Agents can be both producers and consumers of computer-encoded knowledge. The organisation can itself be considered as an agent. In order to be more concrete, one can imagine that individuals (a) and (b) collaborate to the design (Conception) of a document about a particular product and an external source (subcontractor) brings information concerning the externalised work. Depending on the commercial needs, this information can be translated in other languages (Traduction), completed by incorporating the prices (Pricing) and formatted for various uses including computer-treatment out of the organisation. This type of architecture is not futuristic: it is already implemented in knowledge management, EAI, EDI and concurrent engineering.

Figure 1: Structured knowledge transformation within an organisation.

Transformation system engineering will require tools, methodologies and formal methods. As a matter of fact, it will be necessary to check that a particular transformation system does not export sensitive information or that the transformation process terminates. For that purpose, the transformation flow must be expressed in a parsable way and the expected properties of the flow must be expressed (see Transformations and properties). Exmo is concerned by tools and formal methods and aims at combining them in solutions for transformation flow design environments (see Transmorpher).

In the recent years, we turned our interest more specifically towards alignment management which remains tied to transformation system engineering: it is still about composing alignments, satisfying properties and generating transformations from alignments.