There are many concepts relating to interoperability. This section focuses on the basic concepts for the purpose of helping to understand the framework for enterprise interoperability and its underlying domain. These concepts are identified based on the state-of-the-art of relevant interoperability researches [INT 04].
1.2.1. Interoperability barriers
Interoperability barriers are a fundamental concept for understanding interoperability problems. Many interoperability problems are specific to particular application domains. These can be issues like support for particular attributes or particular access control regimes. However, general barriers or problems of interoperability exist and can be identified; and most of them being already addressed [KAS 04, EIF 04, ERI 04]. Consequently, the objective is to identify and categorize those common barriers to interoperability. The term “barrier” means an “incompatibility” or “mismatch” that obstructs the sharing and exchanging of information. Three categories of barriers are identified: (a) conceptual, (b) technological and (c) organizational.
a) Conceptual barriers
Conceptual barriers are concerned with the syntactic and semantic incompatibilities of information to be exchanged. These problems concern the representation of information at the high level of abstraction (such as, for example, the enterprise models of a company) as well as the level of programming (for example, low capacity of semantic representation of XML):
- – syntactic incompatibility can be found whenever different people or systems use different structures (or format) to represent information and knowledge. To tackle this problem, the UEML initiative [UEM 01] developed a neutral model to allow mapping between different enterprise models built with different syntaxes;
- – semantic incompatibility is seen as an important barrier to interoperability as the information and knowledge represented in most of the models or software have no clearly defined semantics to allow unambiguous understanding of the meaning of information. At the current stage of research, the most known technique to solve this problem is semantic annotation and reconciliation using ontology.
Conceptual barriers are the main barriers to interoperability.
b) Technological barriers
Technological barriers are concerned with the use of computers or ICT (Information and Communication Technology) to communicate and exchange information. Typical technological barriers are for example incompatibility of IT architecture & platforms, infrastructure, operating system, etc. From a purely technical perspective, these problems concern the ways to present, store, exchange, process and communicate data and information through the use of software systems. Examples of technological barriers are:
- – communication barriers, e.g. incompatibility of the protocols used to exchange information;
- – content barriers, e.g. different techniques and methods used to represent information, or incompatibility in the tools used to encode/decode the information being exchanged;
- – infrastructure barriers, e.g. use of different incompatible middleware platforms.
Technological barriers are additional barriers with respect to conceptual ones. They are caused by the use of computer. Technological barriers only exist if computers are involved in an interoperation.
c) Organizational barriers
Organizational barriers are concerned with the incompatibilities of organization structure and management techniques implemented in two enterprises. For example, one organization structure barrier is related to the way of assigning responsibility and authority. Indeed, if two companies have different organization structures (e.g. hierarchical vs. networked) and management techniques, some necessary mappings may need to be done before the two sides become interoperable at an operational level:
- – responsibility needs to be defined to allow two parties knowing who is responsible for what (process, data, software, etc.). If responsibility in an enterprise is not clearly and explicitly defined, interoperation between two systems may be obstructed;
- – authority is an organizational concept which defines who is authorized to do what. For example, it is necessary to define who is authorized to create, modify, maintain data, processes, services, etc.;
- – organization structure refers to the style by which responsibility, authority and decision-making are organized. For example, we can talk about centralized versus decentralized organizations, or hierarchical versus matrix or networked organization structures.
Organizational barriers are also additional barriers. Compared with conceptual barriers (centered on information problems) and technological barriers (concerned with IT problems), organizational barriers originate from the problems of humans.
