2010-02-12

BPM reference model from a book about BPM, SOA and EA; fragment 02

... continued from fragment 01

1.2   Process-centric approach  -- processes and services shall be made explicit


The business world understood a long time ago (see, for example, the numerous articles on Business Process Re-engineering, and Quality Management Systems that services (14.4.1) and processes (14.4.4) are the backbones of most enterprise business systems. W. Edwards Deming said "If you can't describe what you are doing as a process, you don't know what you're doing". At present, many enterprises use the process-centric approach as a critical tool to organise their operations as a set of business processes and practices for their management, as well as their improvement.

A service is defined as "an explicitly-defined and operationally-independent unit of functionality". In this context, explicit definition means that a description of the service (i.e. the input, the output and other contractual information such as the duration of the contract) exists. This explicit definition should be the subject of agreement between the service provider and the consumer. Operational independence means that problems in one service do not affect the functioning of another service if the latter does not use the former, i.e. some services are autonomous with respect to other services. For example, a garage may provide both a repair and a sales service. Even if the repair shop is on vacation the sales shop can still function; the services are thus operationally independent.

The implementation of services is not visible and does not need to be. In other words, for a consumer to decide whether he or she wishes to benefit from a particular service, he/she only needs to know the formal description of the service; how the service is implemented by the service provider is irrelevant provided that the service description is fulfilled. For example, banks provide financial services to their customers (who are consumers of those services). Provided that the service descriptions of the financial services are accurate, consumers can select and compare the services offered on the basis of the service description alone, without knowing the banks' internal procedures.

A process is defined as "an explicitly-defined coordination of services to create a particular result". Here explicit definition means that there is a formal description of how services work together. Ideally, such a description should be interpretable not only by a human being, but also by a computer. Coordination means that processes serve as a conductor to manage bigger services which are constituted from smaller services. The bigger services will have a more complex functionality than the smaller simpler services (see figure 1.2), in the same way that an orchestra has a more complex functionality than that of the individual musicians constituting that orchestra.



Figure 1.2   Relationship between processes and services

So, at a process-centric enterprise we may have many elementary nano-services which are organised into a mega-service, i.e. the whole enterprise.

Although the relationships between processes and services are unique and rather complex in each enterprise, the use of explicit definitions allows the formalisation of dependencies between them. As a result, different formal methods (such as simulation, automated validation and automated execution) can be used for enriching the business knowledge (enabling better decisions) and improving the speed of evolution of the enterprise business systems (enabling faster implementation of changes).

... to be continued in fragment 03 ...
Thanks,
AS
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