ReqIF: Follow the Standard

ReqIF – For economically successful change management, follow the standard

The automobile industry knows more than most just how expensive the inconsistent handling of requirements between manufacturers and suppliers can be. For this reason it fully supports a standard that automates the exchange and communication of such requirements. With the aid of the ProSTEP iViP Association, the Requirements Interchange Format (ReqIF) has become, through the agency of the Object Management Group, an international norm. It is only of service, however, when it is actually used – and here there is a pressing need to take action.

Development networks, extended companies and production facilities spread around the globe – this has formed part of the daily business routine for the automobile and aerospace industries for many years, and in general this also applies to the entire manufacturing industry. The basis of each individual step in this complex development and manufacturing network are given by the sets of specifications in which the manufacturers formulate their requirements for components and systems. These requirements form the content matter that the client and the supplier exchange information on during every project and, as is to be expected, the more complex the network and the product, the more important this exchange becomes.

Variety of Automotive Models

Fig. 1: Variety of models from German automobile manufacturers (Source: LIM Working Paper 54 of Bremen University, Economics Faculty)

The dramatic growth of both models and ranges of models planned by the major automobile manufacturers gives an idea of the complexity of the various requirements that will have to be dealt with. The numbers in Fig. 1 are taken from a working paper by Prof. Dr. Christoph Burmann, University of Bremen, issued in September 2014, and predict that within twelve years the number of models built by the BMW Group, Daimler AG and Volkswagen alone will almost double.

The immense increase in the amount of software in the products caused by the extremely short development and change cycles has also been a major contributory factor in this growing complexity. Multidisciplinary products require not only systems engineering methodologies but above all the management of an ever-growing number of requirements. For every type of controller, these functionality requirements are of prime importance since they form the basis for the development and realization of the system. Upper midrange cars contain between 50 and 100 such controllers, with the electronics and the software making the car cockpit look more and more similar to that of an aircraft (see Fig. 2).

Mercedes-Benz G-Class

Fig. 2: Mercedes-Benz G-class 2015 cockpit (Source: Daimler AG)

Keeping the thousands of cross-company requirements between partners up to date can only be done with the aid of IT. Automotive and aerospace were as a result the first who began to work with software for Requirements Management (RM) in a big way, initially with tools that primarily or exclusively concentrate on the management of requirements, such as DOORS from IBM and Rectify from Dassault Systèmes. Requirements however today form part of almost all current ALM (Application Lifecycle Management) and PLM systems. Well-known examples include Integrity Lifecycle Manager from PTC and Teamcenter from Siemens Industry Software.

But as in other areas of use, the exchange of data between differing tools – and even between different versions of the same system – represents an obstacle. It requires an astonishing amount of effort to keep the requirements for a product, a component or an assembly up-to-date. And much of this effort is manual, since requirements can only be automatically updated when they are in the same format.

For this reason, the German automobile industry’s Manufacturers’ Software Initiative (HIS – Herstellerinitiative Software) in 2004 began to work on a neutral XML-based exchange format known as the Requirements Interchange Format (RIF). This represented a great advance and many manufacturers were soon working intensively on this basis. The snag here, however, was that it was not a standard – certainly not an international standard – a great disadvantage in sectors such as aerospace and automotive, where international cooperation is obviously of prime importance.

Establishing the standard

In 2008, therefore, the specification was handed over to the ProSTEP iViP Association to drive the process of standardization, while further development of RIF was simultaneously terminated. Within three years this goal was achieved under the auspices of the Object Management Group (OMG). To avoid misunderstandings with regard to another standard, the new norm was given the acronym ReqIF.

ReqIF contains an XML data model that permits automated transfer of specifications including graphics and tables. In addition, it includes clear rules for the description (and therefore also for the identification) of the data. With ReqIF, an exchange file is exported from an RM tool that can be imported and understood by another system.

Even before ReqIF was released, in 2011 the ProSTEP iViP Association set up, as already done for comparable standardization projects, a ReqIF Implementor Forum that allows tool suppliers and system integrators to agree on the implementation of the standard in their respective systems and on the import and export of the corresponding exchange files. The following companies are currently active on this side of the Implementor Forum: Asaro Systems Ltd, dSPACE GmbH, :em engineering methods AG, Formal Mind GmbH, HOOD GmbH, IBM United Kingdom Ltd., No Magic Europe, Parametric Technology GmbH, PROSTEP AG, ReqTeam GmbH, REQUISIS GmbH and Siemens PLM. Output from this project group flowed into further development of the standard, with the result that the industry, with ReqIF 1.1, has since 2013 possessed an internationally recognized norm supported by the most important suppliers.

The Implementation Guidelines issued by the ReqIF Implementor Forum give all IT and solution suppliers a clear set of rules on how, in their own implementation, they can ensure that all data, metadata and links created in the individual tools are capable of being exchanged.

Unfortunately, the existence of a standard is in no way a guarantee that it will be used by everyone, and many users in this business are taking the attitude “don't stop running horses” – after all, several of them have achieved a certain degree of standardization with RIF. DOORS also offered many companies some sort of standard before the commencement of RIF and ReqIF standardization. But even here a DOORS add-on tool from IBM, originally conceived for exchange between various programs because of the lack of a norm, was used for automatic comparison between differing versions of DOORS. To achieve cooperation between manufacturers, partners and suppliers who have different tools installed, a standard that is widely recognized is needed.

What may be good for a user, however, is invariably not a long-term economically efficient solution for a company either on the user or the provider side. No manufacturer or supplier can afford to depend on a single vendor. Suppliers in particular must exchange data with various manufacturers via different tools or tool versions. Mapping digital specifications in a neutral format is also necessary in order to be able to continue to use them with other systems, for example after an application changeover. Requirements can be very well compared with other product data such as 3-D geometry models since 70 to 80 percent of all requirements, once designed can and must be reused (according to an estimate by Stefan Tautz, IT Project Manager at Continental responsible for data exchange in requirements management). This only works when the data is kept up to date.

Good reasons to use ReqIF

The HIS initiative not only drove forward the definition of a standard exchange format, the manufacturers involved described at the same time a reference process for the exchange of requirements. This documents how the manufacturer and the supplier communicate and with what attributes a supplier can describe his status and any as yet undelivered information or explanations required in an OPL/LOP (list of open points) (see Fig. 3). Exactly this reference process forms the basis for the ReqIF standard, which fully supports the scope of the exchange format in its entirety.

Coordination with OPL/LOP

Fig. 3: Simplified view of the coordination process with an OPL/LOP (Source: HIS)

There are therefore good technical reasons to use ReqIF instead of manual matching or even RIF since this standard has a greater functional scope than RIF and most of the usual RM tools and at the same time functionality has been enormously simplified. In RIF, for example, there were three different concepts to integrate data other than text data, such as images or tables. The corresponding effort to correctly reflect all three concepts in an exchange file was high and also the amount of data was correspondingly large. ReqIF, in contrast, knows only a single "object" element that represents such requirements by means of XHTML. This is a major advantage for all participants because the communication effort is considerably less – for the supplier in implementation as well as for the user.

The most important reason, however, is economic in nature – RIF will not be developed any further, but ReqIF is alive and well and further versions will be produced. While the first represented the initial results of agreements resulting from the manufacturers’ software initiative, the second is now the internationally recognized ReqIF OMG standard.

From the Keynote Haasis

Fig. 4: From the keynote address by Dr. Siegmar Haasis at the ProSTEP iViP Symposium

Dr. Siegmar Haasis, CIO Research and Development Mercedes-Benz Cars at Daimler AG, placed ReqIF at the same level as JT, the neutral 3-D data format and ISO standard, in his concluding keynote address at this year’s ProSTEP iViP Symposium in Stuttgart.

Daimler could not have realized the replacement of its CATIA V5 from Dassault Systèmes by NX from Siemens Industry Software within the planned budget and well before the planned deadline if the manufacturer had not, in addition to the originals, for a number of years saved every CAD model as a neutral JT file. Daimler is now, together with Continental, running a pilot ReqIF project and Dr. Haasis called on all participants to drive forward the use of the ReqIF standard.

At Continental, this call did not fall upon deaf ears. For the supplier, the standard means an even greater reduction in effort than for the manufacturer. Above all, it enormously facilitates cross-company cooperation, particularly internationally – and therefore makes sense for all involved.

Anyone who thinks that this subject affects only the automobile and aerospace industries is mistaken. No machine builder would succeed in taking the step to Industrie 4.0, i.e. to virtual machines, virtual commissioning, predictive maintenance or innovative service offerings when the company concerned did not – as the automobile industry does – depend on systems engineering. This is why “It's OWL” (“Intelligente technische Systeme OstWestfalenLippe” – “Intelligent technical systems from East Westphalia Lippe”) has been recognized as Germany’s leading cluster by the Federal Ministry for Education and Research. “It's OWL” comprises more than one hundred and fifty companies, universities, research institutes and organizations from the Westphalia region, almost all of them being in the mid-range sector. Systems engineering – from requirements management through to smart products – has obviously gained the attention of large parts of industry. And it will be above all the smaller companies who will heavily depend on standards such as ReqIF.

Further information can be found from the homepage of the ProSTEP iViP Association here.

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