Abstract At present, the existing product data formats are not

unified, the enterprise product data and the management information can't directly be shared among the various interior departments of the enterprise and among the enterprises. ISO has recommended STEP (Standards for the Exchange of Product model data). This article gave one three-dimensional enterprise framework described in the multi-views and given the first place to the product data view in entire lifecycle. The methods of using the STEP definition to describe the enterprise model information were expatiated on, giving an instance by these methods. Because the enterprise model information are both easily read and used by model using personnel and can be directly transferred through computer, the effective information integration can be realized among the enterprise models and its each production link.

1. INTRODUCTION

With the developing of the informatization, it is inevitable to carry on non-barrier, the fast exchange between the enterprise as well as enterprise's product data, because enterprise's all activities revolve to its product. At present, there are many product data exchange standards, like US's IGES and PDES, France's AFNOR, German DIN66301 and 66304 VDAFS, and so on. Their common feature is that they separately meet one’s domestic specific demand and fit to small-scale application. This caused the large amount expenses of repetition development, maintenance, data feeds.

Therefore, it is indispensable to establish independent worldwide standard for the product data model exchange and management. With the various countries practice and technical accumulation in standard aspect for many years,

the world standard, STEP, issuing on 1883 and now perfecting, is more and more adopted.

There are many researches on the enterprise modeling and its tool. IBM Rational Rose Data Modeler provided the perfect visualization modeling environment. The integrated modeling tool developed by Tinghua University may realize multi-view modeling, including the process view. These modeling tools may realize certain different form information transformation, like, UML, XML and kind of chart. To cause the information’s directly sharing at product entire lifecycle, a unified product expression standard is only needed.

2. STEP STANDARD

STEP, ISO10303, is an international standard to express and exchange the product data by the way of computer processing. Applying this standard’s goal is to provide a neutral mechanism, independent in any concrete systems, to describe the product data at the entire product lifecycle [1]. STEP is a series and is composed by many categories, such as the description methods, the integrated resources, the application protocols, the realization methods, the consistency test methodologies and the frames, each category including some parts.

The part 11 of the STEP is the description methods. It provides formal description language, EXPRESS, and its graphics model, EXPRESS-G. EXPRESS-G is helpful to understand the data model written with EXPRESS language since the relations among concepts are described by this graph method. In the STEP, all data models are described with EXPRESS.

Enterprise Modeling Using STEP

Wu Huibo1,2, Duan Guolin1, Jia Dongsheng1,Che Yuee1

1.Hebei University of Technology, School of Mechanical Engineering, Tianjin 300130 , China 2.Shijiazhuang Vocational Technology Institute, Mechanical and Electrical Department, Hebei

Shijiazhuang 050082 , China

Email：wuhuibo22222@eyou.com; glduan@hebut.edu.cn

2008 Advanced Software Engineering & Its Applications

978-0-7695-3432-9/08 $25.00 © 2008 IEEE

DOI 10.1109/ASEA.2008.30

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3. ENTERPRISE MODEL FRAMEWORK AND EXPRESSION METHOD 3.1 The integrated enterprise modeling framework based on product data model

At present, the enterprise modeling frame of CIM-OSA is more widespread compared with other frames, for example, ARIS, PERA, GRAI modeling frame and so on. Many modeling methods have profited from its modeling thought.

The development of enterprise modeling approximately passed through two stages. In first stage, the enterprise function view is taken as the core and its typical representative is CIM-OSA. In second stage, the process view does so, like ARIS, Tinghua university's integrated modeling method, the modeling method proposed by Hebei university of technology and so on [2].

A new modeling framework is proposed in this paper, the framework of integrated enterprise modeling based on product data view. It is shown in Figure 1. This framework based on product data view is one three-dimensional framework described in the multi-views and given the first place to the product data view in entire lifecycle. This modeling framework has profited from the thought of CIM-OSA, the modeling framework proposed by Hebei university of technology and the essential feature that all activities of enterprise take the product as central [2]. Its model structure as shown in Figure 1, The entire structure is a three dimensional cube structure composed by general dimensional, the lifecycle and the view model, in which general dimensional includes general level, part general

level and special-purpose level, lifecycle includes demand definition, system design, model implementation and model maintenance, view model includes product data view, function view, information view, organization view and resources view.

This model frame can reflect well the enterprise information and activities and has the very big advance nature and the usability. Comparing with other model frames, it increased a product data view (e.g. Figure 1 heavy line part), that is at the core position in all views and mainly includes the enterprise product classification, respective structure and the correlation data. The modeling thought taking the product as the core is established by the product data view. Looking from the model using personnel's angle, they hoped through the enterprise model to understand what this enterprise does, what the leading product of it is and to have a total understanding about this enterprise’s products. Enterprise model established by the method of taking the product data model as the core and other models for the assistant can satisfy this request, because all enterprise activities are related to the enterprise product. In order to understand an enterprise, this enterprise product should firstly be understood and then to understand its function, information, resources, organization and so on. The mean of the above-mentioned product has broad sense, including goods, software and so on.

3.2 The expression methods of enterprise models

Each view expression way is different with model frame. The traditional method is IDEF (ICAM definition method) method and the tree branch method, for example, expressing the process view with IDEF3, the function view with IDEF0, the information view with IDEF1x, the organization view and the resources view with the tree branch method. UML, UEML （ united enterprise modeling language） and UECML （unified enterprise competence modeling language） are also more and more adopted [3] [4].

Aim at above framework of integrated enterprise modeling based on the model of product data, the description method with EXPRESS language in STEP standard to express various views is proposed in the

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paper. To select this expression method, the multi-view closely related enterprise model, taking the product data view as the core, may be established.

4. TO EXPRESS ENTERPRISE MODEL WITH STEP 4.1 The methods of expressing enterprise model with STEP

Each view of the enterprise model is all expressed by united graph description language defined in STEP Standard. Various views of the enterprise model structure (product data view, function view, information view, resources view, organization view) given in the preceding text all might be used EXPRESS-G to express. Because all views are expressed by a unified way, they are very convenient for personnel modeling and use.

In the method to describe the enterprise model with the EXPRESS-G graphical language, each information unit in the enterprise is called as schema and entity according to certain rule. The names of schema and entity as well as their attribute have uniqueness.

One schema may quote or use another and entity may be nesting definition using the sentences “

supertype of and subtype of”. According to this way, each information unit possibly appears in multi-views and they can be mutually transferred. Ultimately, the enterprise model, which is composed by various views, becomes a closely integrated unit.

All forms of patterns, entities and attributes in the enterprise model are consistent with the STEP standard, but the concrete information content is different from it because of the concrete enterprise. The built enterprise model must conform to the description method and definition in the STEP. In the STEP standard, the EXPRESS language and EXPRESS-G are its main expression ways, in which the unified form using the schema, the entity, the attribute, the rule and so on to describe information unit is defined. In order to conform to the STEP standard, the information expression in the various views of enterprise uses this kind of unified form. Schema and Entity are progressively divided according to the enterprise information connotation size, but the name

of schema, entity and their attribute and rule come from the enterprise content and characteristic.

The feature of the enterprise model described by above method is succinct, intuitionistic and easy to understand. The names of schema and entity are all the enterprise commonly used term and noun. Such model is convenient for personnel to operate and use. While model information is transmitted, it not only includes the data segment information of the STEP standard, but also contains the user-defined information of schemas, entities and their attributes and rules.

4.2 The examples of expressing enterprise model with STEP

The examples of this segment are provided with the above method. The automobile manufacture industry reference models finished by ours task team are expressed with STEP. There are 5 schemas of product data model, function model, information model, resources model and organization model and 256 entities in this database [5]. The following is its small part. 4.2.1 Product data view expression with EXPRESS language

The definition of STEP Schema, entity and the attribute: SCHEMA product_data_view； ENTITY saloon_car； Name：label Description：text END_ENTITY； … ENTITY HX1482； SUBTYPE OF （saloon_car）； Name：label Description：text design-data：1482_design_data END_ENTITY； … ENTITY vehicle_frame； SUBTYPE OF （underpan）； use_equipment1:punch use_equipment2:lathe design-data: 1482_vehicle_frame_design_data

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END_ENTITY； END_SCHEMA； --product_data_view_schema STEP data segment： #1= saloon_car（‘轿车’,’双排座且全封闭’） #2= HX1481（，‘1481’,’两厢’） …

4.2.2 Product data view expression with EXPRESS-G

It is shown in Figure 2.

The product data view nearly contained all enterprise product information. The views of function, information, resources and organization are respectively a part of different aspects pulling out from the product data view. We may see from the above examples, the entity of design-data in the above function also exists in the product data view. Above example only expressed an enterprise model small part and the complete product data view will nearly contain all enterprise model entities as well as their attributes. To establish enterprise model according to this frame and this expression way, the product data view nearly contains all enterprise information about the enterprise product and other views describe enterprise's partial information about the different aspects pulling out from the product data view. The product data view relates closely all enterprise views together through the entity.

5. CONCLUSIONS

Since a complete product life cycle includes a good deal processes, such as product design, manufacture, use,

maintenance and abandonment and so on, the product information is voluminous and complex and disperses in the different department and the area. To better carry out manufacturing informatization, the product information should be understand by computer and the consistent and the integrity be kept during information transmission. The STEP promoted by ISO may satisfy above demands. The eleven syndicates of US aviation industry, United States Navy as well as European Economic Community ESPRIT

all one after another decided to use and support STEP standard.

It is necessary and feasible to describe the enterprise model with the STEP. This article gave one three-dimensional enterprise framework described in the multi-views, including product data, function, information, resource, organization, and given the first place to the product data view, and a series of concrete methods to describe above enterprise model

through the example with the STEP standard.

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[4]Gregoire Pepiot, Naoufel Cheikhrouhou, Jean-Marie

Furbringer, et al. UECML: Unified Enterprise Competence

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