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CIMOSA and GERAM Standardisation in Enterprise Engineering
Copyright © IFAC Information Control in Manufacturing, Nancy - Metz, France, 1998
CIMOSA and GERAM Standardisation in Enterprise Engineering K. Kosanke 1 and F. Vemadar
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CIMOSA Association e. V, Stockholmerstr. 7, D-71034 BOblingen, Germany Fac. Des Sciences, Universite de Metz, lie du Saulcy, F-57012 France
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Abstract: The new industrial paradigms on agile, extended and virtual enterprises require co-operation on rather short notice and between partners with limited knowledge on each other competencies. Enterprise models provide a very efficient method to verify and validate the contributions of the partners. However, this requires the availability of relevant models, a common understanding of their contents, establishing of a common model and its execution on available ICf platforms. International standardisation is the most appropriate way to achieve this very much needed commonality in enterprise modelling. Standardisation in this area exists with ENVs on modelling framework and modelling constructs. Both European pre-standards are based on CIMOSA. ISO standards are on concepts and rules for enterprise modelling and on requirements for enterprise reference architectures and methodologies. The latter is based on GERAM, the work of the IF ACIIFIP Task Force. The paper will describe CIMOSA and GERAM and provide an overview on the standardisation work. Relations of current architectures (ARIS, CIMOSA, GRAIlGIM, IEM, PERA) to GERAM and the ENV 12204 will be presented. Copyright© 1998 IFAC
Keywords: CIMOSA, Enterprise Modelling, Enterprise Reference Architecture, GERAM, Standardisation.
1 INTRODUCTION
Organisation of a virtual enterprise requires - beside many other tasks - the identification, verification and validation of the contributions of all the different partners involved in the virtual enterprise. Enterprise modelling can significantly support these management tasks by verifying the contributions to the operation of the virtual enterprise. If the different partners can provide models of their parts of the operational processes, the intended operation can be evaluated through simulation of the combined models.
Virtual enterprises will become a common form of enterprise operation, allowing exploitation of market opportunities an short notice and with partners with complementing competencies as required by the identified market needs. This new form of cooperation will enable enterprises to operate more profitable due to the increased use of their assets and competencies. However, such co-operation requires a high degree of operational flexibility and very demanding marketing and management capabilities, enabling the recognition of opportunities and the organisation of the required virtual enterprise.
However, to join different enterprise models into a common model requires a common understanding of the model contents by the people involved, simple linking mechanisms across model interfaces and
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three representative methodologies (CIMOSA 2, GRAIlGIM3, and PERA 4),the analysis resulted in a generalisation of the three methodologies.
portability of the models on leT platfonns. International standardisation will be very helpful in achieving a common model representation for both people and ICT equipment
GERAM provides a framework which identifies the elements recommended in enterprise engineering and integration. This framework sets the standard for the collection of tools and methods from which any enterprise would benefit by more successfully tackle change processes. GERAM does not impose any particular set of tools or methods, but defines the criteria to be satisfied by any set of selected tools and methods. It views enterprise models as an essential component of enterprise engineering and integration. The set of components identified in GERAM is shown in Figure 1 and is briefly described in the following.
Standardisation in enterprise modelling started in Europe within CEN/CENELEC and resulted in the European pre-norrn ENV 40003 (CEN, 1990). This ENV provides a generic framework for enterprise modelling. The IFAClIFIP Task Force has further developed this framework into GERAM 1 (Bernus, et al, 1996a) identifying the different components needed in enterprise engineering and integration. Work has been carried out in ISO on a more generic level, defining rules and guidelines in its IS 14258 (ISO, 1996) and again in CEN on the definition of constructs for enterprise modelling ENV 12204 (CEN, 1995a). CEN has initiated work on model portability with its studies on EMEIS (Enterprise Model Execution and Integration Services) (CEN 1995b/c). Work on a new ISO standard (ISO, 1998a), tries to encompass the different approaches. The new work item, which is based on GERAM (ISO, 1998b), the IFACIIFIP input to standardisation, is not only concerned with enterprise modelling, but includes human aspects and computer based support services as well.
The most important component GERA (Generic Enterprise Reference Architecture) identifies the basic concepts to be used in enterprise engineering and integration (e.g. life-cycles and life histories of enterprise entities). GERAM distinguishes between the methodologies for enterprise engineering (EEMs) and the modelling languages (EMLs). The latter are used by the methodologies to describe the structure, content and behaviour of the enterprise. These languages will enable the modelling of the enterprise operation as business processes identifying their supporting technologies as well. The modelling process produces enterprise models (EMs) which represent part or all of the enterprise operations, including its manufacturing or service tasks, its organisation and management, and its control and information systems. These models are to be used to guide the implementation of the operational system of the enterprise (EOSs) as well as to improve the ability of the enterprise to evaluate operational or organisational alternatives (e.g. through simulation), and thereby enhance its performance.
The work on standardisation has to be seen in relation to the current state of the art (Bernus 1996b, Vernadat 1996). Especially in enterprise modelling a number of methods have been introduced to the user community and are employed in enterprise engineering and reengineering projects. The standards introduced on European and international level will allow the different methodologies to coexist, but ask for harmonisation of the model contents representation (Kosanke, 1997). The most challenging, but still remaining task is the creation of awareness and acceptance in the user and vendor community. A task to which initiatives like the Europe and USA supported ICEIMT (international Conference on Enterprise Integration and Modelling Technology) (Kosanke, NeU, 1997) contribute, but which need the dedication of all the people involved in the field of enterprise engineering and integration.
The methodologies and the languages used for enterprise modelling are implemented in enterprise engineering tools (EETs). The methodologies and languages are supported by ontologies, meta models and glossaries which are collectively represented as generic enterprise modelling concepts (GEMCs). The modelling process is enhanced by using partial models (PEMs) which provide reusable models of human roles, processes and technologies.
2 GERAM GERAM has been defined by the IF AC/IFIP Task Force (Bernus, et al, 1996a) as a framework for enterprise engineering and integration. The Task Force has been initiated to consolidate the state of the art in enterprise integration. Focussing its effort on
Generalised Enterprise Reference Architecture and Methodology
2
CIM Open Systems Architecture
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Graphs with Results and Activities InterrelatedlGRAI Integrated Methodology
4 Purdue Enterprise Reference Architecture
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from being able to commonly refer to the capabilities of their architectures, without having to rewrite their documents to comply with GERAM. Users of these architectures would benefit from GERAM because the GERAM definitions would allow them to identify what they could (and what they could not) expect from any chosen particular architecture in connection with an enterprise integration methodology and its proposed supporting components. In the following, only the GERA component of GERAM will be presented in more details.
The operational use of enterprise models is supported by specific modules (EMOs) which provide prefabricated products like human skill profiles for specific professions, common business procedures (e.g. banking and tax rules) or ICf infrastructure services to be employed in the implementation and use of the operational system (EOSs). Potentially, all proposed reference architectures and methodologies could be characterised in GERAM so that developers of particular architectures could gain
GER
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EMLs
EEMs
Generalised Enterprise Reference Architecture identifies concepts of enterprise integration
Enterprise Modelling Languages provide modelling constructs for modelling of human role, processes and technologies
Enterprise Engineering Methodologies descrbe process of enterprise engineering
: employs
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Lf
utilise
U r implemented in
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GEMCs
PEMs
Generic Enterprise Modelling Concepts define the meaning of enterprise modelling constructs
Partial Enterprise Models provide reusable referenre models of human roles, processes and technologies
EEls Enterprise Engineering Tools support enterprise engineering
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support
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T
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EMs Enterprise Models represent the parlicular enterprise operation
EMOs Enterprise Modules provide implementable modules of human professions, operational processes, technologies
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EOS Enterprise Operational Systems support the operation of the parlicular enterprise
Fig. 1: GERAM (Generalised Enterprise Reference Architecture) Framework Components
2.1 GERA (Generic Enterprise Reference Architecture)
enterprise engineering and integration projects. These concepts can be categorised as:
The enterprise reference architecture of GERAM relates to all of the known enterprise modelling methodologies (see below). GERA defines the enterprise related generic concepts recommended for use in
Human oriented concepts (a) to describe the role of humans as an integral part of the organisation and operation of an enterprise and (b) to support humans during enterprise design, construction and change. The concepts cover human aspects such as capabilities,
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skills, know-how and competencies as well as the roles of humans in the enterprise organisation and the enterprise operation. The organisation related aspects have to do with decision level, responsibilities and authorities. The operational aspects relate to the capabilities and quality of humans as enterprise resources. In addition, the communication aspects of humans have to be recognised to cover interoperation with other humans and with teclmology elements when realising enterprise operations.
2. J. J Life-Cycle and Life-Cycle Activities Figure 2 shows the GERA life-cycle for any enterprise or for any of its entities. The different life-cycle stages define types of activities which are pertinent during the life of the entity. A total of seven life-cycle activity types have been defined, which my be subdivided further as demonstrated for the design type activities. Identification: activities identifying the contents of the particular entity under consideration in tenns of its boundaries and its relation to its internal and external environments.
Process oriented concepts for the description of the business processes of the enterprise deal with enterprise operations (functionality and behaviour) and cover enterprise entity life-cycle and Iife-cycle activities, life history, enterprise entity types, enterprise modelling with integrated model representation and model views.
Concept: activities needed to develop the concept of the underlying entity. The concept includes the definition of the entity's mission, vision, values, strategies, objectives, operational concepts, policies, business plans etc.
Technology oriented concepts provide for the description of the business process which support the technology involved in both enterprise operation and enterprise engineering efforts (modelling and model use support). Such concepts are concerned with infrastructures used to support processes and include for instance resource models (information teclmology, manufacturing teclmology, office automation and others), facility layout models, information system models, communication system models and logistics models. Only three process oriented concepts identified in GERA will be further described in the following.
Requirement: activities needed to develop descriptions of operational requirements of the enterprise entity, its relevant processes and the collection of all their functional, behavioural, information and resource needs. Design: activities supporting the specification of the entity with all of its components that satisfy the entity requirements. Implementation: activities defining all those tasks which must be carried out to build or re-build (i.e. manifest) the entity. Operation: activities needed during its operation for monitoring, controlling, and evaluating the operation / perfonnance and the quality of the customer services and products. Decommissioning: activities needed for re-missioning, retraining, redesign, recycling, preservation, transfer, disbanding, disassembly, or disposal of all or part of the entity or its products and customer services, at the end of its useful life in operation.
Concept I I _ .........~
R~irement
Preliminary design
2. J.2 Life History
Design Dettlled design
The life history of a business entity is the representation of all the different tasks which have been carried out on the particular entity during its entire life span. Relating to the life-cycle concept described above, allows to identify the different tasks as Iife-cycle activities. This demonstrates the iterative nature of the life-cycle concept compared with the by definition linear time sequence of the life history (Figure 3). The iterations identify different change processes required on the operational processes and or the product or customer services.
Implementation Operation
Decommission
Fig. 2: GERA Life-Cycle Stages - Activity Types for any Enterprise or its Entity
Typically, multiple change processes are in effect at anyone time, and all of these processes may run in
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Life-Cycle Dimension: provides for the controlled modelling process of enterprise entities according to the life-cycle activities.
parallel with the operation of the entity. Moreover, change processes may interact with each other. Within one process, such as a continuous improvement project, multiple life-cycle activities would be active at anyone time. E.g. concurrent engineering design and implementation processes may be executed within one enterprise engineering process.
Genericity Dimension: provides for the controlled particularisation (instantiation) process from generic and partial to particular. Model View Dimension: provides for the controlled visualisation of specific aspects of the enterprise entity.
2.1.3 Modelling Framework ofGERA GERA provides a modelling framework which is based on the life-cycle concept and identifies three dimensions for structuring the components of enterprise modelling .
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... HactiVitYtYl)esH... Identification Concept Requirement Design mplementation Operation
Decommissioning ro 'ccl
Decommission
Time(Life History) Fig. 3: Parallel Processes in the Entity's Life-History
Figure 4 shows the three dimensional structure identified above which represents the modelling framework. The reference part of the modelling framework itself consists of the generic and the partial levels only. These two levels organise the definitions of concepts and basic and macro level constructs (the modelling languages). The particular level represents the results of the modelling process - the model of the enterprise entity as it corresponds to the particular set of lifecycle activities. However, the modelling language should support the two-way relationship between models of adjacent life-cycle stages, i.e. the derivation of models from an upper to a lower state or the abstraction of models from a lower to an upper state, rather than having to create different models for the different sets of life-cycle activities.
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Fig. 4: The Enterprise Modelling Framework with the Resulting Particular Enterprise Model
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3 CIMOSAs
defined model views and several stages of the GERA life-cycle concept. CIMOSA supports the engineering of enterprise models from requirements definition to implementation description, their operational use and maintenance. Figure 5 shows the CIMOSA Modelling Framework which identifies three main life cycle stages: Requirements Definition, Design Specification and Implementation Description.
CIMOSA has been developed by the AMICE Consortium as part of the European Esprit initiative (AMICE 1993, CIMOSA 1996) and is further maintained and extended by the CIMOSA Association e.V. CIMOSA defines both a framework for enterprise modelling and an integrating infrastructure for model execution. CIMOSA models are intended to be used for operational support rather than for project guidance in developing or re-engineering business entities. Operational use is seen as decision support for evaluating operational alternatives, as well as model driven operation control and monitoring.
Comparing this with the GERA definition of the Life Cycle of any Entity (Figure 3) shows that CIMOSA does not cover the first two stages of the GERA defined life-cycle. However, its three stages correspond to the major engineering stages. With the emphasis on enterprise engineering CIMOSA considers the operation phase not to be part of its life cycle. However, it places emphasis on the model release for operation especially for model maintenance and system change. Only if models are really kept up-todate - representing the real state of the enterprise, rather than some historic state - will enterprise models be able to play a role in enterprise integration for decision support in day-to-day operation.
CIMOSA models the enterprise operations as sets of interacting processes capturing both their functionality and their dynamic behaviour. Processes are considered to fulfil business objectives by producing relevant results. Processes will cross enterprise organisational boundaries and include customers and suppliers in the
Extending CIMOSA to cover the two missing upper life-cycle stages is considered feasible and relevant extensions will be made in the future . With such extensions CIMOSA will not only be able to identify and use the relevant information in the same model it will also provide the related modelling lan~ge (generic constructs and partial models) and will enable modelling views for these stages of the life cycle as well.
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Derivation 01 Models
Generic Level
Partial Level
ParticulaLevel
3.2 Enterprise Modelling Language Enterprise models must represent the enterprise operations from various modelling viewpoints. CIMOSA defines a modelling language which has been a major input for the European pre-standard ENV 12204 (CEN 1995a). To build a particular enterprise model, CIMOSA provides a set of business modelling constructs and elements which are easily understandable by the business user and which cover all the important aspects of a enterprise operation and enterprise system. ICT oriented modelling constructs complement this set for use by system design and implementation experts.
Fig. 5: CIMOSA Modelling Framework value adding chain. Therefore CIMOSA is concerned with the enterprise itself and the relations to its environment Enterprises may be individual organisations as well as extended or virtual enterprises. CIMOSA distinguishes between the internal engineering and operation environment, putting emphasis on a formal release of enterprise models from engineering to operation.
The CIMOSA business modelling constructs and their elements used for enterprise modelling are shown in Figure 6. These modelling constructs or building blocks provide for a common representation of the model contents to the user and are the basis for the definition of the ICT related representation which enables the required model portability and interoperability.
3.1 Modelling Framework The CIMOSA framework has been the basis for the European pre-standard ENV 40003 (CEN 1990). It is comparable with the GERA modelling framework (Figure 4) providing the same levels of genericity (generic, partial and particular), a sub set of the GERA
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Additional constructs are needed to model humans and their roles in enterprise operation. The ICEIMT initiative has identified this need and has proposed
CIM Open System Architecture
388
enterprise operation is still required to verify and validate these requirements.
additions to the set of constructs defined in ENV 12204. However research work on human aspects in
Structuring Concepts CIMOSA Object Class (Generic Building Block) (Building Block Ty pe)
Meta Model
Object Class
B
Doma;n and BuslDess Process Event Procedural Rules
Enterprise Object
Enterpri se Activity
Object View
Functional Operation
Information Element
Structure
Capability Set Resource (Functional Entity) Capability Resource Component
Organisation Cell/Unit
Organisation Element
CIMOSA Business Modelling Constructs
Fig. 6: CIMOSA Modelling Language Constructs accompanying standardisation in the ler domain as well. Figure 7 shows a proposal for the standardisation strategy which identifies a hierarchy of standards addressing both the modelling and the ICT domain of enterprise engineering and integration.
4 STANDARDISATION Standardisation efforts are needed which improve the understanding of enterprise models and provide easy interoperability between models from different partners. Standardisation will not only be very helpful for the users of such models but for the providers of the supporting infonnation technology as well. Users will be able to link and evaluate their business processes in temporary co-operations and ler vendors will gain confidence in the market and see a return on investments in their product developments.
The current status of standardisation on ISO and CEN level identifies a basic set of standardisation concepts for enterprise modelling. The ISO IS 14258 identifies the basic definitions of enterprise modelling. These rules and guidelines have to be inherited by any lower level standard in the modelling domain. A candidate for the modelling framework standard is GERAM as defined by the IFAClIFIP TASK Force. The CEN prestandard ENV 40003 has to be understood as corresponding to the reference architecture defined as in GERAM.
Standardisation in enterprise engineering and enterprise integration has progressed in several areas. Europe has already started work in the early 90' s which resulted in the pre-standards ENV 40003 (CEN 1990) and ENV 12204 (CEN 1995a) mentioned previously. Also some work has been done on standardisation of ler based model support with the analysis of relevant state of the art and requirements for EMEIS (CEN 1995b/c), the enterprise model execution and integration services. The IFAC/IFIP Task Force has defined GERAM (ISO 1998b) and submitted it to ISO as the base for the new work item on requirements for enterprise reference architectures and methodologies. ISO has issued IS 14258 rules and guidelines for enterprise modelling (ISO 1996).
The ISO New Work Item on requirements for enterprise reference architectures and methodologies would therefore define the requirements for the ENV 40003 or for any GERA like reference architectures. The ENV 12204 on modelling constructs would relate to another component of the modelling framework, the modelling languages. On the same level would be a standard for modelling tools or for the model development services of an integrating infrastructure as defined in the CEN work on EMEIS. Each standard on this level could have sub-levels like graphical representations of modelling constructs to support common understanding of enterprise models.
However there is still much work to be done to achieve a sufficient set of standards for enterprise engineering and integration. Therefore standardisation has to continue its top-down strategy for the enterprise modelling domain and has to provide the sufficient
The ler related standards follow the same general structure starting with rules and guidelines for infra-
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structure definitions. Using the CEN EMEIS concept, model execution services and general Ier services supporting model development and execution will be defined with general functionalities needed for model execution. Again lower level standards on individual services may be defined. Also the model development services or modelling tools have to comply with the general guidelines to ensure reusability of service functions.
standardisation work. The ICEIMT efforts have identified some starting points for relevant work. E.g. representation of the communication between people may be an item to be considered in any future work on modelling constructs. To complete the standardisation strategy, rules and guidelines for enterprise engineering would be the highest level standard to be obeyed in any enterprise integration and enterprise engineering effort.
Standardisation of human related items still requires R&D work to be done to provide a basis for the
FWI : Rules and Guidelines for In frastructures
IS 14258 Rules and Guidelines for Modelling
Related Standards
ISO WD 15704 : Requirements for Enterprise Reference Architectures and Methodologies State of the Art: GERA . ENV 40003 Modelling Framework) FWI : Process Repr . ENV 12204 Con stru cts for M od .
FWI : Human related Represen tation s
FWI : Infrastructure Fram ework - State of the Art: EMEIS
FWI : Human Roles
FWI: Model Developm . Services
FWI: Human Skills
FWI : Model Execution Services
FW) : (Human Behaviour?)
FWI : General IT Services
FWI : Icons for Mod. Constructs FWI : IT rep . for M od . Con structs
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ISO 9000
ISO 14000
others (tbd)
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Legend: FWI = Future Work Item
Fig. 7. El Standardisation Strategy - a Proposal ling support for the information technology part of the enterprise (ICT concept support). ARIS supports enterprise modelling from operation concept and leT concept to leT system implementation.
5 STATE OF THE ART AND STANDARDISATION Several modelling methodologies have been analysed for their capabilities in enterprise integration (Kosanke 1997). GERAM (ISO 1998b), as defined by the IFACIIFIP Task and the ENV 12204 (CEN 1995a) the European pre standard on modelling construct have been used as references for the methodologies and the modelling languages, respectively.
GRAIIGIM: The methodology was initially developed to model the decisionaI structure of a manufacturing enterprise for strategic, tactical and operational planning. GRAI was extended to support the design of eIM systems leading to GIM as an integrated methodology for business process modelling. With special emphasis on the decisionaI aspects concept (analysis), structure (user oriented design) and realisation (technical oriented design) stages of the life-cycle concept are supported.
The following modelling methodologies have been mapped onto the GERA life cycle concept: ARIS6. CIMOSA. GRAIlGIM, IEM7 and PERA.
ARlS: The focus is on the enterprise information system design. Therefore it provides specific model-
6
IEM: It is used to support creation of enterprise models for business re-engineering and therefore allows also to model process dynamics for evaluation of operational alternatives. IEM supports the main stages of the enterprise life-cycle (requirements, design, implementation and model up-date).
ARchitecture for Information Systems Integrated Enterprise Modelling
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design, implementation) by all modelling methodologies. PERA distinguishes between a specification and a detailed design layer. The first two layers - identification of the Business Entity and definition of its concepts like management policies, etc are provided by PERA only. The other methodologies assume this information to be provided by management.
PERA: Is intended to support and guide the development of the master plan for an enterprise business entity. The methodology covers the complete project of introduction, implementation and operation of an enterprise business entity which may be either part of a larger entity or be the complete enterprise itself. The life-cycle starts with the definition of the business entity to be modelled, identifying its mission, vision, management philosophy, mandates, defines project sponsors, leaders and members, etc. and ends with obsolescence of the plant at the end of the operational phase.
The Operation Layer is explicitly defined in PERA only. CIMOSA distinguishes between the enterprise engineering environment and the operation environment assuming models to be used as operational support (decision support tool) and in model driven operation control and monitoring. The decommission phase of the GERA life cycle is not yet explicitly addressed in any of the analysed methodologies. The GRAIlGIM modelling framework distinguishes between three architectural levels (Concept, Structure, Realisation) and three modelling activities (Analysis, User Oriented Design, Technical Oriented Design).
5. J Modelling Framework Comparison A comparison of the modelling methodologies is shown in Table 1. For details on the difference in terminology see reference (Kosanke 1997). However, there is a surprisingly high level of tenninology consistence.
Life-Cycle Dimension: It indicates a rather similar coverage of the centre life-cycle stages (requirement,
Table 1. Modelling Framework Comparison GERAM Identification Concept Requirements Design - PreliminaIy - Detailed Implementation Operation Decommission
ARIS
yes yes
yes
CIMOSA GRAIIGIM Life-Cycle Dimension
yes yes
yes yes
IEM
yes yes
yes
yes
PERA yes yes yes yes yes yes yes
Model View Dimension Function Infonnation Resource Organisation Decision Generic Partial Particular
yes yes (yes) yes
yes yes yes yes
yes yes
yes yes yes (yes)
yes yes yes yes
yes Genericity Dimension (yes) yes
yes
yes yes yes
(yes) yes
yes yes
yes
provides a similar approach, but has identified the Control View for integrating the different views into a common process model. GRAIlGIM and PERA identify different views, but there is as yet no real integration into one consistent model yet.
Model View Dimension: Different views on the model help to reduce model complexity for the user. Such model views are provided by most methodologies, however, not all with the same capabilities (see table 2). CIMOSA assumes one consistent enterprise model on which particular views allow model engineering on a particular aspect of the enterprise. ARIS
391
defined in ENV 12204, the constructs of the different languages are related to the different views defined in GERA.
PERA changes its view concept across the life-cycle stages from a global view for the first and part of the second layer of its life cycle, to two views (Infonnation Architecture and Manufacturing Architecture) for most of layer two and all of layer three. Thereafter, PERA continues with three views (Infonnation Systems Architecture, Human & Organisation Architecture, Manufacturing Equipment Architecture). GRAIlGIM identifies a unique Decision View which is at the centre of the GRAI methodology enabling modelling of strategic, tactical and operational decision making.
All methodologies support the representation of the model contents by modelling constructs and provide a rather good coverage of the reference set. Only PERA relies mainly on textual description rather than defining a generic modelling language. However, due to the different aims of the methodologies, the expressiveness of the particular languages differ. Only CIMOSA has the vision of an executable model for decision support and operation control and monitoring. Therefore its modelling language is a very expressive one. All other methodologies are focusing on particular situations from enterprise integration project descriptions (PERA), decision systems modelling and CIM system design (GRAIlGIM), infonnation system design (ARIS) to business process re-engineering (IEM). Therefore their modelling languages are tuned to particular application areas resulting in more specialised constructs like ARIS (ICT resource description), GRAI (decision view) and IEM (special object classes: Product, Order, Resource). PERA with its use of textual description is only using a construct for representation of task and its infonnation inputs and outputs.
Genericify Level Dimension: This framework dimension separates the particular model from the reference architecture which supports model creation. The reference architecture may contain generic building blocks or constructs for modelling and reference or partial models which may be used as macros in the modelling process. Except for PERA which only provides a single task module, all methodologies have a rather populated generic level and almost all provide sets ofpartiallreference models as well.
5.2 Model Representation - Modelling Language Comparison The constructs of the modelling language enable collection of relevant information for describing the enterprise objects, allowing one to represent enterprise processes, activities, information, resources and organisation.
Most methodologies provide some structuring defmitions in addition to the specific constructs. These definitions identify either the model contents (GRAIlGIM, PERA) or distinguish between model engineering and model use (CIMOSA).
Table 2 provides an overview of the modelling languages provided by the different modelling methodologies. Using as reference the set of 12 constructs
Table 2: Modelling Language Comparison
ENV 12204
ARIS
CfMOSA
GRAfl GIM
fEM
Function
4
3
4
1
4
Information
5
2
2
2
3
GERAMViews
Resource Organisation
2 1
6
3
2
2
1
Decision Total
PERA
2/5 12
11
12
8
10
1
organisation boundaries will never become a reality. A reality which is very much desirable for joint ventures, subcontractors or the more modem versions of extended and virtual enterprise.
6 CONCLUSIONS There is an urgent need for the user of enterprise modelling technologies for model common representation, compatibility and interoperability. Otherwise enterprise engineering and integration across
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The current state of the art provides some common ground for the harmonisation of enterprise engineering and integration technology. The results of the IF AClIFIP Task Force provide a rather promising basis for further convergence of the efforts on support technology. The comparison between GERAM and five different reference architectures and methodologies shows the many commonalties already existing in their tenninology and structure. However, common understanding and model interoperability still requires more harmonisation efforts in user and ICf oriented modelling languages.
CEN (1995b). CIM Systems Architecture - Enterprise model execution and integration services - Statement of Requirements; CEN Report CR: 1832, CENffC31O. CEN (l995c). CIM Systems Architecture - Enterprise model execution and integration services - Evaluation report, CEN Report CR: 1831, CENffC31O. CIMOSA Association e.V., (1996). CIMOSA - Open System Architecture for CIM, Technical Baseline; Version 3.0, private publication, 1994; version 3.2 (Hypertext) partly updated 1996.
Therefore standardisation has to continue its topdown strategy for the enterprise engineering and integration domain and has to provide sufficient standardisation in the ICT domain as well. A proposal for the standardisation strategy is presented which identifies a hierarchy of standards addressing both the modelling and the ICf domain of enterprise engineering and integration. The current status of standardisation on ISO and CEN level identifies a basic set of standardisation concepts for enterprise modelling. But more work is still required
ISO (1996). IS 14258, Industrial automation systems - Rules and guidelines for enterprise models; ISO TC 184/SC5IWG 1. ISO (1998a). WO 15704, Requirements for Enterprise Reference Architectures and Methodologies, ISO TC184/SC5IWGl. ISO (I 998b}. N 420, GERAM: Generalised Enterprise Reference A rchitecture and Methodologies, ISO TC184/SC5IWGl.
7 REFERENCES :
Kosanke, K. (1997). Comparison of Enterprise Modelling Methodologies; in Information Infrastructure Systems for ManufactUring, Proceedings DIISM'96, Goossenaerts, 1., Kimura, F., Wortmann, H., (Ed), Chapman and HaIl, London, (ISBN 0-41278800 4).
AMICE, ESPRIT Consortium, (1993) CIMOSA Open System Architecture for CIM; SpringerVerlag, Berlin Heidelberg New York, (ISBN 3540-56256-7). Bemus, P., Nemes, L., Williams, TJ., (Ed.), (1996a). Architectures for Enterprise Integration; Chapman & Hall, London, (ISBN 0-41273140 I). Bemus, P. , Nemes, L., (Ed.) (1996b). Modelling and Methodologies for Enterprise Integration; Chapman & HalL London, (ISBN 0-412 75630 7).
Kosanke, K., Nell, J.G., (Ed.) (1997). Enterprise Engineering and Integration: BUilding International Consensus; Proceedings ICEIMT'97, Springer-Verlag, Berlin Heidelberg New York, (ISBN 3-540-63402-9).
CEN (1990). ENV 40003, Computer Integrated Manufacturing - Systems Architecture - Framework for Enterprise Modelling; CEN/CENELEC.
Vernadat., F.B., (1996). Enterprise Modelling and Integration: principles and applications; Chapman & Hall, London, (ISBN 0 412 60550 3).
CEN (1995a). ENV 12204, Advanced Manufacturing Technology - Systems Architecture - Constructs for Enterprise Modelling; CEN TC 31OIWG1 .
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CIMOSA and GERAM Standardisation in Enterprise Engineering K. Kosanke 1 and F. Vemadar
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CIMOSA Association e. V, Stockholmerstr. 7, D-71034 BOblingen, Germany Fac. Des Sciences, Universite de Metz, lie du Saulcy, F-57012 France
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Abstract: The new industrial paradigms on agile, extended and virtual enterprises require co-operation on rather short notice and between partners with limited knowledge on each other competencies. Enterprise models provide a very efficient method to verify and validate the contributions of the partners. However, this requires the availability of relevant models, a common understanding of their contents, establishing of a common model and its execution on available ICf platforms. International standardisation is the most appropriate way to achieve this very much needed commonality in enterprise modelling. Standardisation in this area exists with ENVs on modelling framework and modelling constructs. Both European pre-standards are based on CIMOSA. ISO standards are on concepts and rules for enterprise modelling and on requirements for enterprise reference architectures and methodologies. The latter is based on GERAM, the work of the IF ACIIFIP Task Force. The paper will describe CIMOSA and GERAM and provide an overview on the standardisation work. Relations of current architectures (ARIS, CIMOSA, GRAIlGIM, IEM, PERA) to GERAM and the ENV 12204 will be presented. Copyright© 1998 IFAC
Keywords: CIMOSA, Enterprise Modelling, Enterprise Reference Architecture, GERAM, Standardisation.
1 INTRODUCTION
Organisation of a virtual enterprise requires - beside many other tasks - the identification, verification and validation of the contributions of all the different partners involved in the virtual enterprise. Enterprise modelling can significantly support these management tasks by verifying the contributions to the operation of the virtual enterprise. If the different partners can provide models of their parts of the operational processes, the intended operation can be evaluated through simulation of the combined models.
Virtual enterprises will become a common form of enterprise operation, allowing exploitation of market opportunities an short notice and with partners with complementing competencies as required by the identified market needs. This new form of cooperation will enable enterprises to operate more profitable due to the increased use of their assets and competencies. However, such co-operation requires a high degree of operational flexibility and very demanding marketing and management capabilities, enabling the recognition of opportunities and the organisation of the required virtual enterprise.
However, to join different enterprise models into a common model requires a common understanding of the model contents by the people involved, simple linking mechanisms across model interfaces and
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three representative methodologies (CIMOSA 2, GRAIlGIM3, and PERA 4),the analysis resulted in a generalisation of the three methodologies.
portability of the models on leT platfonns. International standardisation will be very helpful in achieving a common model representation for both people and ICT equipment
GERAM provides a framework which identifies the elements recommended in enterprise engineering and integration. This framework sets the standard for the collection of tools and methods from which any enterprise would benefit by more successfully tackle change processes. GERAM does not impose any particular set of tools or methods, but defines the criteria to be satisfied by any set of selected tools and methods. It views enterprise models as an essential component of enterprise engineering and integration. The set of components identified in GERAM is shown in Figure 1 and is briefly described in the following.
Standardisation in enterprise modelling started in Europe within CEN/CENELEC and resulted in the European pre-norrn ENV 40003 (CEN, 1990). This ENV provides a generic framework for enterprise modelling. The IFAClIFIP Task Force has further developed this framework into GERAM 1 (Bernus, et al, 1996a) identifying the different components needed in enterprise engineering and integration. Work has been carried out in ISO on a more generic level, defining rules and guidelines in its IS 14258 (ISO, 1996) and again in CEN on the definition of constructs for enterprise modelling ENV 12204 (CEN, 1995a). CEN has initiated work on model portability with its studies on EMEIS (Enterprise Model Execution and Integration Services) (CEN 1995b/c). Work on a new ISO standard (ISO, 1998a), tries to encompass the different approaches. The new work item, which is based on GERAM (ISO, 1998b), the IFACIIFIP input to standardisation, is not only concerned with enterprise modelling, but includes human aspects and computer based support services as well.
The most important component GERA (Generic Enterprise Reference Architecture) identifies the basic concepts to be used in enterprise engineering and integration (e.g. life-cycles and life histories of enterprise entities). GERAM distinguishes between the methodologies for enterprise engineering (EEMs) and the modelling languages (EMLs). The latter are used by the methodologies to describe the structure, content and behaviour of the enterprise. These languages will enable the modelling of the enterprise operation as business processes identifying their supporting technologies as well. The modelling process produces enterprise models (EMs) which represent part or all of the enterprise operations, including its manufacturing or service tasks, its organisation and management, and its control and information systems. These models are to be used to guide the implementation of the operational system of the enterprise (EOSs) as well as to improve the ability of the enterprise to evaluate operational or organisational alternatives (e.g. through simulation), and thereby enhance its performance.
The work on standardisation has to be seen in relation to the current state of the art (Bernus 1996b, Vernadat 1996). Especially in enterprise modelling a number of methods have been introduced to the user community and are employed in enterprise engineering and reengineering projects. The standards introduced on European and international level will allow the different methodologies to coexist, but ask for harmonisation of the model contents representation (Kosanke, 1997). The most challenging, but still remaining task is the creation of awareness and acceptance in the user and vendor community. A task to which initiatives like the Europe and USA supported ICEIMT (international Conference on Enterprise Integration and Modelling Technology) (Kosanke, NeU, 1997) contribute, but which need the dedication of all the people involved in the field of enterprise engineering and integration.
The methodologies and the languages used for enterprise modelling are implemented in enterprise engineering tools (EETs). The methodologies and languages are supported by ontologies, meta models and glossaries which are collectively represented as generic enterprise modelling concepts (GEMCs). The modelling process is enhanced by using partial models (PEMs) which provide reusable models of human roles, processes and technologies.
2 GERAM GERAM has been defined by the IF AC/IFIP Task Force (Bernus, et al, 1996a) as a framework for enterprise engineering and integration. The Task Force has been initiated to consolidate the state of the art in enterprise integration. Focussing its effort on
Generalised Enterprise Reference Architecture and Methodology
2
CIM Open Systems Architecture
3
Graphs with Results and Activities InterrelatedlGRAI Integrated Methodology
4 Purdue Enterprise Reference Architecture
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from being able to commonly refer to the capabilities of their architectures, without having to rewrite their documents to comply with GERAM. Users of these architectures would benefit from GERAM because the GERAM definitions would allow them to identify what they could (and what they could not) expect from any chosen particular architecture in connection with an enterprise integration methodology and its proposed supporting components. In the following, only the GERA component of GERAM will be presented in more details.
The operational use of enterprise models is supported by specific modules (EMOs) which provide prefabricated products like human skill profiles for specific professions, common business procedures (e.g. banking and tax rules) or ICf infrastructure services to be employed in the implementation and use of the operational system (EOSs). Potentially, all proposed reference architectures and methodologies could be characterised in GERAM so that developers of particular architectures could gain
GER
I
EMLs
EEMs
Generalised Enterprise Reference Architecture identifies concepts of enterprise integration
Enterprise Modelling Languages provide modelling constructs for modelling of human role, processes and technologies
Enterprise Engineering Methodologies descrbe process of enterprise engineering
: employs
~
Lf
utilise
U r implemented in
-,
GEMCs
PEMs
Generic Enterprise Modelling Concepts define the meaning of enterprise modelling constructs
Partial Enterprise Models provide reusable referenre models of human roles, processes and technologies
EEls Enterprise Engineering Tools support enterprise engineering
I I
support
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I used to build I
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EMs Enterprise Models represent the parlicular enterprise operation
EMOs Enterprise Modules provide implementable modules of human professions, operational processes, technologies
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EOS Enterprise Operational Systems support the operation of the parlicular enterprise
Fig. 1: GERAM (Generalised Enterprise Reference Architecture) Framework Components
2.1 GERA (Generic Enterprise Reference Architecture)
enterprise engineering and integration projects. These concepts can be categorised as:
The enterprise reference architecture of GERAM relates to all of the known enterprise modelling methodologies (see below). GERA defines the enterprise related generic concepts recommended for use in
Human oriented concepts (a) to describe the role of humans as an integral part of the organisation and operation of an enterprise and (b) to support humans during enterprise design, construction and change. The concepts cover human aspects such as capabilities,
385
skills, know-how and competencies as well as the roles of humans in the enterprise organisation and the enterprise operation. The organisation related aspects have to do with decision level, responsibilities and authorities. The operational aspects relate to the capabilities and quality of humans as enterprise resources. In addition, the communication aspects of humans have to be recognised to cover interoperation with other humans and with teclmology elements when realising enterprise operations.
2. J. J Life-Cycle and Life-Cycle Activities Figure 2 shows the GERA life-cycle for any enterprise or for any of its entities. The different life-cycle stages define types of activities which are pertinent during the life of the entity. A total of seven life-cycle activity types have been defined, which my be subdivided further as demonstrated for the design type activities. Identification: activities identifying the contents of the particular entity under consideration in tenns of its boundaries and its relation to its internal and external environments.
Process oriented concepts for the description of the business processes of the enterprise deal with enterprise operations (functionality and behaviour) and cover enterprise entity life-cycle and Iife-cycle activities, life history, enterprise entity types, enterprise modelling with integrated model representation and model views.
Concept: activities needed to develop the concept of the underlying entity. The concept includes the definition of the entity's mission, vision, values, strategies, objectives, operational concepts, policies, business plans etc.
Technology oriented concepts provide for the description of the business process which support the technology involved in both enterprise operation and enterprise engineering efforts (modelling and model use support). Such concepts are concerned with infrastructures used to support processes and include for instance resource models (information teclmology, manufacturing teclmology, office automation and others), facility layout models, information system models, communication system models and logistics models. Only three process oriented concepts identified in GERA will be further described in the following.
Requirement: activities needed to develop descriptions of operational requirements of the enterprise entity, its relevant processes and the collection of all their functional, behavioural, information and resource needs. Design: activities supporting the specification of the entity with all of its components that satisfy the entity requirements. Implementation: activities defining all those tasks which must be carried out to build or re-build (i.e. manifest) the entity. Operation: activities needed during its operation for monitoring, controlling, and evaluating the operation / perfonnance and the quality of the customer services and products. Decommissioning: activities needed for re-missioning, retraining, redesign, recycling, preservation, transfer, disbanding, disassembly, or disposal of all or part of the entity or its products and customer services, at the end of its useful life in operation.
Concept I I _ .........~
R~irement
Preliminary design
2. J.2 Life History
Design Dettlled design
The life history of a business entity is the representation of all the different tasks which have been carried out on the particular entity during its entire life span. Relating to the life-cycle concept described above, allows to identify the different tasks as Iife-cycle activities. This demonstrates the iterative nature of the life-cycle concept compared with the by definition linear time sequence of the life history (Figure 3). The iterations identify different change processes required on the operational processes and or the product or customer services.
Implementation Operation
Decommission
Fig. 2: GERA Life-Cycle Stages - Activity Types for any Enterprise or its Entity
Typically, multiple change processes are in effect at anyone time, and all of these processes may run in
386
Life-Cycle Dimension: provides for the controlled modelling process of enterprise entities according to the life-cycle activities.
parallel with the operation of the entity. Moreover, change processes may interact with each other. Within one process, such as a continuous improvement project, multiple life-cycle activities would be active at anyone time. E.g. concurrent engineering design and implementation processes may be executed within one enterprise engineering process.
Genericity Dimension: provides for the controlled particularisation (instantiation) process from generic and partial to particular. Model View Dimension: provides for the controlled visualisation of specific aspects of the enterprise entity.
2.1.3 Modelling Framework ofGERA GERA provides a modelling framework which is based on the life-cycle concept and identifies three dimensions for structuring the components of enterprise modelling .
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... HactiVitYtYl)esH... Identification Concept Requirement Design mplementation Operation
Decommissioning ro 'ccl
Decommission
Time(Life History) Fig. 3: Parallel Processes in the Entity's Life-History
Figure 4 shows the three dimensional structure identified above which represents the modelling framework. The reference part of the modelling framework itself consists of the generic and the partial levels only. These two levels organise the definitions of concepts and basic and macro level constructs (the modelling languages). The particular level represents the results of the modelling process - the model of the enterprise entity as it corresponds to the particular set of lifecycle activities. However, the modelling language should support the two-way relationship between models of adjacent life-cycle stages, i.e. the derivation of models from an upper to a lower state or the abstraction of models from a lower to an upper state, rather than having to create different models for the different sets of life-cycle activities.
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Fig. 4: The Enterprise Modelling Framework with the Resulting Particular Enterprise Model
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3 CIMOSAs
defined model views and several stages of the GERA life-cycle concept. CIMOSA supports the engineering of enterprise models from requirements definition to implementation description, their operational use and maintenance. Figure 5 shows the CIMOSA Modelling Framework which identifies three main life cycle stages: Requirements Definition, Design Specification and Implementation Description.
CIMOSA has been developed by the AMICE Consortium as part of the European Esprit initiative (AMICE 1993, CIMOSA 1996) and is further maintained and extended by the CIMOSA Association e.V. CIMOSA defines both a framework for enterprise modelling and an integrating infrastructure for model execution. CIMOSA models are intended to be used for operational support rather than for project guidance in developing or re-engineering business entities. Operational use is seen as decision support for evaluating operational alternatives, as well as model driven operation control and monitoring.
Comparing this with the GERA definition of the Life Cycle of any Entity (Figure 3) shows that CIMOSA does not cover the first two stages of the GERA defined life-cycle. However, its three stages correspond to the major engineering stages. With the emphasis on enterprise engineering CIMOSA considers the operation phase not to be part of its life cycle. However, it places emphasis on the model release for operation especially for model maintenance and system change. Only if models are really kept up-todate - representing the real state of the enterprise, rather than some historic state - will enterprise models be able to play a role in enterprise integration for decision support in day-to-day operation.
CIMOSA models the enterprise operations as sets of interacting processes capturing both their functionality and their dynamic behaviour. Processes are considered to fulfil business objectives by producing relevant results. Processes will cross enterprise organisational boundaries and include customers and suppliers in the
Extending CIMOSA to cover the two missing upper life-cycle stages is considered feasible and relevant extensions will be made in the future . With such extensions CIMOSA will not only be able to identify and use the relevant information in the same model it will also provide the related modelling lan~ge (generic constructs and partial models) and will enable modelling views for these stages of the life cycle as well.
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,
Derivation 01 Models
Generic Level
Partial Level
ParticulaLevel
3.2 Enterprise Modelling Language Enterprise models must represent the enterprise operations from various modelling viewpoints. CIMOSA defines a modelling language which has been a major input for the European pre-standard ENV 12204 (CEN 1995a). To build a particular enterprise model, CIMOSA provides a set of business modelling constructs and elements which are easily understandable by the business user and which cover all the important aspects of a enterprise operation and enterprise system. ICT oriented modelling constructs complement this set for use by system design and implementation experts.
Fig. 5: CIMOSA Modelling Framework value adding chain. Therefore CIMOSA is concerned with the enterprise itself and the relations to its environment Enterprises may be individual organisations as well as extended or virtual enterprises. CIMOSA distinguishes between the internal engineering and operation environment, putting emphasis on a formal release of enterprise models from engineering to operation.
The CIMOSA business modelling constructs and their elements used for enterprise modelling are shown in Figure 6. These modelling constructs or building blocks provide for a common representation of the model contents to the user and are the basis for the definition of the ICT related representation which enables the required model portability and interoperability.
3.1 Modelling Framework The CIMOSA framework has been the basis for the European pre-standard ENV 40003 (CEN 1990). It is comparable with the GERA modelling framework (Figure 4) providing the same levels of genericity (generic, partial and particular), a sub set of the GERA
5
Additional constructs are needed to model humans and their roles in enterprise operation. The ICEIMT initiative has identified this need and has proposed
CIM Open System Architecture
388
enterprise operation is still required to verify and validate these requirements.
additions to the set of constructs defined in ENV 12204. However research work on human aspects in
Structuring Concepts CIMOSA Object Class (Generic Building Block) (Building Block Ty pe)
Meta Model
Object Class
B
Doma;n and BuslDess Process Event Procedural Rules
Enterprise Object
Enterpri se Activity
Object View
Functional Operation
Information Element
Structure
Capability Set Resource (Functional Entity) Capability Resource Component
Organisation Cell/Unit
Organisation Element
CIMOSA Business Modelling Constructs
Fig. 6: CIMOSA Modelling Language Constructs accompanying standardisation in the ler domain as well. Figure 7 shows a proposal for the standardisation strategy which identifies a hierarchy of standards addressing both the modelling and the ICT domain of enterprise engineering and integration.
4 STANDARDISATION Standardisation efforts are needed which improve the understanding of enterprise models and provide easy interoperability between models from different partners. Standardisation will not only be very helpful for the users of such models but for the providers of the supporting infonnation technology as well. Users will be able to link and evaluate their business processes in temporary co-operations and ler vendors will gain confidence in the market and see a return on investments in their product developments.
The current status of standardisation on ISO and CEN level identifies a basic set of standardisation concepts for enterprise modelling. The ISO IS 14258 identifies the basic definitions of enterprise modelling. These rules and guidelines have to be inherited by any lower level standard in the modelling domain. A candidate for the modelling framework standard is GERAM as defined by the IFAClIFIP TASK Force. The CEN prestandard ENV 40003 has to be understood as corresponding to the reference architecture defined as in GERAM.
Standardisation in enterprise engineering and enterprise integration has progressed in several areas. Europe has already started work in the early 90' s which resulted in the pre-standards ENV 40003 (CEN 1990) and ENV 12204 (CEN 1995a) mentioned previously. Also some work has been done on standardisation of ler based model support with the analysis of relevant state of the art and requirements for EMEIS (CEN 1995b/c), the enterprise model execution and integration services. The IFAC/IFIP Task Force has defined GERAM (ISO 1998b) and submitted it to ISO as the base for the new work item on requirements for enterprise reference architectures and methodologies. ISO has issued IS 14258 rules and guidelines for enterprise modelling (ISO 1996).
The ISO New Work Item on requirements for enterprise reference architectures and methodologies would therefore define the requirements for the ENV 40003 or for any GERA like reference architectures. The ENV 12204 on modelling constructs would relate to another component of the modelling framework, the modelling languages. On the same level would be a standard for modelling tools or for the model development services of an integrating infrastructure as defined in the CEN work on EMEIS. Each standard on this level could have sub-levels like graphical representations of modelling constructs to support common understanding of enterprise models.
However there is still much work to be done to achieve a sufficient set of standards for enterprise engineering and integration. Therefore standardisation has to continue its top-down strategy for the enterprise modelling domain and has to provide the sufficient
The ler related standards follow the same general structure starting with rules and guidelines for infra-
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structure definitions. Using the CEN EMEIS concept, model execution services and general Ier services supporting model development and execution will be defined with general functionalities needed for model execution. Again lower level standards on individual services may be defined. Also the model development services or modelling tools have to comply with the general guidelines to ensure reusability of service functions.
standardisation work. The ICEIMT efforts have identified some starting points for relevant work. E.g. representation of the communication between people may be an item to be considered in any future work on modelling constructs. To complete the standardisation strategy, rules and guidelines for enterprise engineering would be the highest level standard to be obeyed in any enterprise integration and enterprise engineering effort.
Standardisation of human related items still requires R&D work to be done to provide a basis for the
FWI : Rules and Guidelines for In frastructures
IS 14258 Rules and Guidelines for Modelling
Related Standards
ISO WD 15704 : Requirements for Enterprise Reference Architectures and Methodologies State of the Art: GERA . ENV 40003 Modelling Framework) FWI : Process Repr . ENV 12204 Con stru cts for M od .
FWI : Human related Represen tation s
FWI : Infrastructure Fram ework - State of the Art: EMEIS
FWI : Human Roles
FWI: Model Developm . Services
FWI: Human Skills
FWI : Model Execution Services
FW) : (Human Behaviour?)
FWI : General IT Services
FWI : Icons for Mod. Constructs FWI : IT rep . for M od . Con structs
I I
I
ISO 9000
ISO 14000
others (tbd)
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Legend: FWI = Future Work Item
Fig. 7. El Standardisation Strategy - a Proposal ling support for the information technology part of the enterprise (ICT concept support). ARIS supports enterprise modelling from operation concept and leT concept to leT system implementation.
5 STATE OF THE ART AND STANDARDISATION Several modelling methodologies have been analysed for their capabilities in enterprise integration (Kosanke 1997). GERAM (ISO 1998b), as defined by the IFACIIFIP Task and the ENV 12204 (CEN 1995a) the European pre standard on modelling construct have been used as references for the methodologies and the modelling languages, respectively.
GRAIIGIM: The methodology was initially developed to model the decisionaI structure of a manufacturing enterprise for strategic, tactical and operational planning. GRAI was extended to support the design of eIM systems leading to GIM as an integrated methodology for business process modelling. With special emphasis on the decisionaI aspects concept (analysis), structure (user oriented design) and realisation (technical oriented design) stages of the life-cycle concept are supported.
The following modelling methodologies have been mapped onto the GERA life cycle concept: ARIS6. CIMOSA. GRAIlGIM, IEM7 and PERA.
ARlS: The focus is on the enterprise information system design. Therefore it provides specific model-
6
IEM: It is used to support creation of enterprise models for business re-engineering and therefore allows also to model process dynamics for evaluation of operational alternatives. IEM supports the main stages of the enterprise life-cycle (requirements, design, implementation and model up-date).
ARchitecture for Information Systems Integrated Enterprise Modelling
390
design, implementation) by all modelling methodologies. PERA distinguishes between a specification and a detailed design layer. The first two layers - identification of the Business Entity and definition of its concepts like management policies, etc are provided by PERA only. The other methodologies assume this information to be provided by management.
PERA: Is intended to support and guide the development of the master plan for an enterprise business entity. The methodology covers the complete project of introduction, implementation and operation of an enterprise business entity which may be either part of a larger entity or be the complete enterprise itself. The life-cycle starts with the definition of the business entity to be modelled, identifying its mission, vision, management philosophy, mandates, defines project sponsors, leaders and members, etc. and ends with obsolescence of the plant at the end of the operational phase.
The Operation Layer is explicitly defined in PERA only. CIMOSA distinguishes between the enterprise engineering environment and the operation environment assuming models to be used as operational support (decision support tool) and in model driven operation control and monitoring. The decommission phase of the GERA life cycle is not yet explicitly addressed in any of the analysed methodologies. The GRAIlGIM modelling framework distinguishes between three architectural levels (Concept, Structure, Realisation) and three modelling activities (Analysis, User Oriented Design, Technical Oriented Design).
5. J Modelling Framework Comparison A comparison of the modelling methodologies is shown in Table 1. For details on the difference in terminology see reference (Kosanke 1997). However, there is a surprisingly high level of tenninology consistence.
Life-Cycle Dimension: It indicates a rather similar coverage of the centre life-cycle stages (requirement,
Table 1. Modelling Framework Comparison GERAM Identification Concept Requirements Design - PreliminaIy - Detailed Implementation Operation Decommission
ARIS
yes yes
yes
CIMOSA GRAIIGIM Life-Cycle Dimension
yes yes
yes yes
IEM
yes yes
yes
yes
PERA yes yes yes yes yes yes yes
Model View Dimension Function Infonnation Resource Organisation Decision Generic Partial Particular
yes yes (yes) yes
yes yes yes yes
yes yes
yes yes yes (yes)
yes yes yes yes
yes Genericity Dimension (yes) yes
yes
yes yes yes
(yes) yes
yes yes
yes
provides a similar approach, but has identified the Control View for integrating the different views into a common process model. GRAIlGIM and PERA identify different views, but there is as yet no real integration into one consistent model yet.
Model View Dimension: Different views on the model help to reduce model complexity for the user. Such model views are provided by most methodologies, however, not all with the same capabilities (see table 2). CIMOSA assumes one consistent enterprise model on which particular views allow model engineering on a particular aspect of the enterprise. ARIS
391
defined in ENV 12204, the constructs of the different languages are related to the different views defined in GERA.
PERA changes its view concept across the life-cycle stages from a global view for the first and part of the second layer of its life cycle, to two views (Infonnation Architecture and Manufacturing Architecture) for most of layer two and all of layer three. Thereafter, PERA continues with three views (Infonnation Systems Architecture, Human & Organisation Architecture, Manufacturing Equipment Architecture). GRAIlGIM identifies a unique Decision View which is at the centre of the GRAI methodology enabling modelling of strategic, tactical and operational decision making.
All methodologies support the representation of the model contents by modelling constructs and provide a rather good coverage of the reference set. Only PERA relies mainly on textual description rather than defining a generic modelling language. However, due to the different aims of the methodologies, the expressiveness of the particular languages differ. Only CIMOSA has the vision of an executable model for decision support and operation control and monitoring. Therefore its modelling language is a very expressive one. All other methodologies are focusing on particular situations from enterprise integration project descriptions (PERA), decision systems modelling and CIM system design (GRAIlGIM), infonnation system design (ARIS) to business process re-engineering (IEM). Therefore their modelling languages are tuned to particular application areas resulting in more specialised constructs like ARIS (ICT resource description), GRAI (decision view) and IEM (special object classes: Product, Order, Resource). PERA with its use of textual description is only using a construct for representation of task and its infonnation inputs and outputs.
Genericify Level Dimension: This framework dimension separates the particular model from the reference architecture which supports model creation. The reference architecture may contain generic building blocks or constructs for modelling and reference or partial models which may be used as macros in the modelling process. Except for PERA which only provides a single task module, all methodologies have a rather populated generic level and almost all provide sets ofpartiallreference models as well.
5.2 Model Representation - Modelling Language Comparison The constructs of the modelling language enable collection of relevant information for describing the enterprise objects, allowing one to represent enterprise processes, activities, information, resources and organisation.
Most methodologies provide some structuring defmitions in addition to the specific constructs. These definitions identify either the model contents (GRAIlGIM, PERA) or distinguish between model engineering and model use (CIMOSA).
Table 2 provides an overview of the modelling languages provided by the different modelling methodologies. Using as reference the set of 12 constructs
Table 2: Modelling Language Comparison
ENV 12204
ARIS
CfMOSA
GRAfl GIM
fEM
Function
4
3
4
1
4
Information
5
2
2
2
3
GERAMViews
Resource Organisation
2 1
6
3
2
2
1
Decision Total
PERA
2/5 12
11
12
8
10
1
organisation boundaries will never become a reality. A reality which is very much desirable for joint ventures, subcontractors or the more modem versions of extended and virtual enterprise.
6 CONCLUSIONS There is an urgent need for the user of enterprise modelling technologies for model common representation, compatibility and interoperability. Otherwise enterprise engineering and integration across
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The current state of the art provides some common ground for the harmonisation of enterprise engineering and integration technology. The results of the IF AClIFIP Task Force provide a rather promising basis for further convergence of the efforts on support technology. The comparison between GERAM and five different reference architectures and methodologies shows the many commonalties already existing in their tenninology and structure. However, common understanding and model interoperability still requires more harmonisation efforts in user and ICf oriented modelling languages.
CEN (1995b). CIM Systems Architecture - Enterprise model execution and integration services - Statement of Requirements; CEN Report CR: 1832, CENffC31O. CEN (l995c). CIM Systems Architecture - Enterprise model execution and integration services - Evaluation report, CEN Report CR: 1831, CENffC31O. CIMOSA Association e.V., (1996). CIMOSA - Open System Architecture for CIM, Technical Baseline; Version 3.0, private publication, 1994; version 3.2 (Hypertext) partly updated 1996.
Therefore standardisation has to continue its topdown strategy for the enterprise engineering and integration domain and has to provide sufficient standardisation in the ICT domain as well. A proposal for the standardisation strategy is presented which identifies a hierarchy of standards addressing both the modelling and the ICf domain of enterprise engineering and integration. The current status of standardisation on ISO and CEN level identifies a basic set of standardisation concepts for enterprise modelling. But more work is still required
ISO (1996). IS 14258, Industrial automation systems - Rules and guidelines for enterprise models; ISO TC 184/SC5IWG 1. ISO (1998a). WO 15704, Requirements for Enterprise Reference Architectures and Methodologies, ISO TC184/SC5IWGl. ISO (I 998b}. N 420, GERAM: Generalised Enterprise Reference A rchitecture and Methodologies, ISO TC184/SC5IWGl.
7 REFERENCES :
Kosanke, K. (1997). Comparison of Enterprise Modelling Methodologies; in Information Infrastructure Systems for ManufactUring, Proceedings DIISM'96, Goossenaerts, 1., Kimura, F., Wortmann, H., (Ed), Chapman and HaIl, London, (ISBN 0-41278800 4).
AMICE, ESPRIT Consortium, (1993) CIMOSA Open System Architecture for CIM; SpringerVerlag, Berlin Heidelberg New York, (ISBN 3540-56256-7). Bemus, P., Nemes, L., Williams, TJ., (Ed.), (1996a). Architectures for Enterprise Integration; Chapman & Hall, London, (ISBN 0-41273140 I). Bemus, P. , Nemes, L., (Ed.) (1996b). Modelling and Methodologies for Enterprise Integration; Chapman & HalL London, (ISBN 0-412 75630 7).
Kosanke, K., Nell, J.G., (Ed.) (1997). Enterprise Engineering and Integration: BUilding International Consensus; Proceedings ICEIMT'97, Springer-Verlag, Berlin Heidelberg New York, (ISBN 3-540-63402-9).
CEN (1990). ENV 40003, Computer Integrated Manufacturing - Systems Architecture - Framework for Enterprise Modelling; CEN/CENELEC.
Vernadat., F.B., (1996). Enterprise Modelling and Integration: principles and applications; Chapman & Hall, London, (ISBN 0 412 60550 3).
CEN (1995a). ENV 12204, Advanced Manufacturing Technology - Systems Architecture - Constructs for Enterprise Modelling; CEN TC 31OIWG1 .
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