3 Part 3: V-Modell Reference Tailoring

3.2 Directives and Instructions for Tailoring

The »V-Modell is a guideline for planning and executing development projects, taking into account the entire system life cycle. It regulates the results to be prepared in a project and describes the concrete procedures for preparing these results. In addition, the V-Modell specifies the responsibilities of the individual project members.

The V-Modell is a generic process model, which can be employed in different project constellations, the so-called »Project Types. The different project types, which can be based on an approach offered by the V-Modell, are described in the chapter »Project Types.

A project type describes a concrete project constellation and the mandatory »Process Modules. A process module realizes a concrete task which may arise within the scope of a »V-Modell Project, e.g. project management or software development. A process module comprises the »Work Product s and »Activityies which are relevant for fulfilling this task and thus belong together with regard to their contents. In addition, process modules describe which V-Modell »Roles are responsible for completing the products and which roles cooperate in the development. Moreover, different »Project Characteristics providing additional selectable process modules are assigned to each project type. Finally, a project type specifies a rough framework for the execution of the project, which will be devoped further in the following steps and concretized in a »Project Execution Strategy.

Process modules describe the result structure of a project, but do not specify in which sequence the results have to be prepared. A sequence of this type is specified by the so-called »Project Execution Strategy. The project execution strategy of a project is largely determined by the selected »Project Type Variant and may, in individual cases, be influenced by project characteristics. In the V-Modell, project type variants are assigned unambiguously to a project type, thus refining it.

Each project type offers at least one project type variant. Complementing the project type, project type variants specify not only the project execution strategy but also additional mandatory process modules. Depending on the selected project type variant, the tailoring process assigns values to the project characteristics, making it possible to add additional process modules and certain procedural steps of the project execution strategy to the project. The concrete project execution strategy for a project is specified if the tailoring is completed and all »Project Characteristics have been assigned a value. During the tailoring process, the possible project type variant for a concrete project will be selected.

Tailoring Process

The poject-specific adaptation of the V-Model, the so-called »Tailoring, only determines the »Project Type, selects the possible »Project Type Variant and assigns values to the appropriate »Project Characteristics. It is not necessary to select or delete the activities and products of the V-Modell individually.The tailoring process creates an »Application Profile by following the above-mentioned steps. The step-by-step selection restricts further options in accordance with the situation. For example, after selection of a project type, it is only possible to select project type variants assigned to the selected project type. This restriction does not only affect the process modules, but also the »Decision Gates required by the project execution strategy resulting from the project type variant. From the comprehensive V-Modell, the tailoring process only selects only those components required for the current project constellation and combines them in a consistent manner.

Normally, this application profile will be defined at the beginning of a project and remain stable during project execution. This is designated as »Static Tailoring. However, it may happen that certain project characteristics change during project execution, e.g., it could be possible that hardware portions are identified in the course of a project which was at first dedicated exclusively to software development purposes. In this case, it is possible to select additional process modules and to adapt work flows in the project execution strategy during project execution. This process is designated as »Dynamic Tailoring.

The Tailoring is described in detail by the sub-activities (cf. »V-Modell Reference Activities)

of the process module »Project Management.

Tailoring Documentation

The Tailoring documented in the »Project Manual is limited to the selection of the process modules and the project execution strategy decisive for the planning. It is not necessary to select or delete individual products or activities. The adaptation of the V-Modell exceeding the Tailoring process, the determination of » Product Instances and »Activity Instances will be executed during the project planning in accordance with the specifications of the generative »Product Dependency (see also »Project Planning ).


Figure 3: Tailoring Facilities


Figure 4: Tailoring Facilities (continued)

If a product model must be created in the project due to the specifications of the generative product dependencies, the structure is specified in form of subjects (see also »Templates). Subjects must not be deleted so that the uniformity of the documents of projects compliant to the V-Modell will be ensured. In individual cases, however, subjects may be marked as "not relevant in the special context of the project" in the product model.