Djamel Yousnadj
email: djamel.yousnadj@ensam.eu

Guillaume Jouanne
email: g.jouanne@evea-conseil.com

Nicolas Maranzana
email: nicolas.maranzana@ensam.eu

Frédéric Segonds
email: frederic.segonds@ensam.eu

Carole Bouchard
email: carole.bouchard@ensam.eu

Améziane Aoussat
email: ameziane.aoussat@ensam.eu

Integration of environmental assessment in a PLM context: a case study in luxury industry

Keywords: Simplified LCA, Product portfolio assessment, Eco-design, PLM

Nowadays, the environment becomes a major issue in our society. It gives rise to regulations, market demand and stakeholder's pressure which are concerning companies. These latter have to reduce the negative impact of their new product by eco-design and adopting a continuous improvement for their existing product portfolio. To do so, environmental assessment system is needed. Life Cycle Assessment (LCA) is the most known and recognized. However, this method is complex, requires significant resources and a large amount of accurate data. We propose a methodology to connect a simplified LCA tool with PLM system and ERP to evaluate an entire product portfolio at any time. This will allow design teams to consider the environmental issues in early design phase and gives the companies a global vision of their product portfolio. This methodology is experimented with packaging products of luxury brand, using the Teamcenter PLM system and a Simplified LCA Tool.

Introduction

Nowadays, the environment becomes a major issue in our society [START_REF] Van Hemel | Barriers and stimuli for ecodesign in SMEs[END_REF][START_REF] Pochat | Integrating ecodesign by conducting changes in SMEs[END_REF][START_REF] Mathieux | Product ecodesign and materials: current status and future prospects[END_REF]. Governments are key drivers for environmental and sustainable management practices. They may coerce actions trough regulations, and use fines and trade barriers. Companies have also to deal with Non-Governmental Organizations requirements, or risk a loss in their brand value and a negative impact on global marketing and production strategies [START_REF] Gmelin | Determinants of a sustainable new product development[END_REF]. But the central objective of a company to remain competitive is fulfilling customer needs, which are increasingly directed toward the social and environmental performance of a product [START_REF] Gmelin | Determinants of a sustainable new product development[END_REF]. These different stakeholders ask companies for environmental certificates such as ISO 14001 [START_REF]ISO 14001 -Environmental management systems: Requirements with guidance for use[END_REF], FSC 1while products have to be developed quicker since the market requests new ones frequently [START_REF] Gmelin | Determinants of a sustainable new product development[END_REF].

In this context companies have to develop not only competitive products but to make them also more respectful to the environment [START_REF] Eigner | A Concept For An Intuitive And Interactive Fully Plm-Integrated Eco-Efficiency Assessment In Real-Time[END_REF]. They have to reduce the negative impact of their new product by eco-design and adopting a continuous improvement for their existing product portfolio. To do so, environmental assessment system is needed and Life Cycle Assessment (LCA) is the most known and recognized. However, this method is complex, requires significant resources and large amount of accurate data. Numerous researches propose Simplified Life Cycle Assessment (SLCA) tools which streamline the data collection. This make it more usable at the early stages of design with reliable results [START_REF] Morbidoni | Enabling an efficient SLCA by interfacing selected PLM LCI parameters[END_REF][START_REF] Morbidoni | CAD-Integrated LCA Tool: Comparison with dedicated LCA Software and Guidelines for the Improvement[END_REF][START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF]. When companies need to establish carbon footprint report, eco-labels on their products or engaging continuous improvement actions, they first need a reliable environmental assessment of the whole product portfolio. However, it still requires important resources and data for big companies' portfolio, even by using SLCA.

In this paper, we propose a methodology to connect a SLCA tool with PLM and ERP systems. This will help to evaluate the entire product portfolio (existing and developing product) of luxury industry at any time.

After this introduction, the second section presents a brief review on eco-design tools and environmental PLM Systems. Section 3 proposes a methodology to connect SLCA tool to PLM/ERP system. This proposal is experimented in section 4, and further works and perspectives will be presented in section 5.

From eco-design tool to environmental PLM system

Eco-design tools

Eco-design is a methodology for designing products and services, which considers in particular the reduction of their environmental impact throughout their complete lifecycle, "from cradle to grave", without compromising other criteria like function, quality, cost and appearance. Several eco-design approaches have been studied and many tools and methods exist [START_REF] Trela | Integration of EcoDesign in the early steps of the innovation process[END_REF][START_REF] Rio | Improving Design to Environment Modeling knowledge transformations within product designers and environmental engineers activities[END_REF]. However their industrial use is still limited [START_REF] Lindahl | Engineering designers' experience of design for environment methods and tools -Requirement definitions from an interview study[END_REF]. Some classifications exist but we took Janin's one which identifies two main categories of eco-design tools: Environmental assessment ones, and improvement ones that help designers to find eco-design solutions [START_REF] Janin | Ecodesign approach in company -A stake: building a coherence between tools and design process[END_REF]. In this paper, we will focus our study on the assessment tool that we will connect to PLM system. They enable the comparison of the existing products, or a product against a norm, a recommendation, or even legislation. They also allow the identification of the weakest points of the product to find a path towards improvement [START_REF] Trela | Integration of EcoDesign in the early steps of the innovation process[END_REF]. Two main categories may be distinguished: qualitative and quantitative assessment tool.

Qualitative assessment tools. These qualitative tools, such as checklist and guidelines/rules, are the easiest to use and are among the most prevalent tools in the industry, especially in SME. Checklist is a set of items used for quick assessing a product from the environmental perspective over its entire life cycle [START_REF] Trela | Integration of EcoDesign in the early steps of the innovation process[END_REF][START_REF] Cluzel | Towards Parametric Environmental Profiles of Complex Industrial Systems in Preliminary Design Stage[END_REF][START_REF] Leroy | Development of a methodology to reliable environmental decisions from life cycle assessment based on analysis and management of uncertainty on inventory data[END_REF] as "are toxic materials used in the product?". Guidelines/rules can enhance the design process and ensure that the most important environmental issues and impacts are addressed. The most famous are the ten golden rules which are a highly generic guidelines adapted for product development process [START_REF] Luttropp | EcoDesign and The Ten Golden Rules: generic advice for merging environmental aspects into product development[END_REF]. The enterprises can also develop more concrete and specific guidelines in relation to their own specific product development context [START_REF] Favi | Toward eco-design: an integrated lifecycle engineering system to develop sustainable mechatronic products and services[END_REF]. These tools are developed particularly for the early stages of the product design. They can also be considered as "improvement tool" as they propose a way to reduce the environmental impact by focusing on one item [START_REF] Ramani | Integrated Sustainable Life Cycle Design: A Review[END_REF]. However, challenge remains when trade-offs exists between different life cycle stages or different environment impact categories [START_REF] Ramani | Integrated Sustainable Life Cycle Design: A Review[END_REF]. The proper use of these tools requires extensive experience and knowledge. Compared with quantitative tools, qualitative ones are more subjective.

Quantitative assessment tools. Many tools exist to evaluate the environmental impacts associated to product lifecycle but Life Cycle Assessment (LCA) is the most popular and recognized [START_REF] Pochat | Integrating ecodesign by conducting changes in SMEs[END_REF][START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF]. It provides quantitative data on product environmental impact along its complete lifecycle: from the extraction and production of material to the end-of-life. Known as the most mature tool for eco-design [START_REF] Favi | Toward eco-design: an integrated lifecycle engineering system to develop sustainable mechatronic products and services[END_REF], it has been formalized in the ISO series 14040 and implemented in various software tool [START_REF] Favi | Toward eco-design: an integrated lifecycle engineering system to develop sustainable mechatronic products and services[END_REF]. LCA is divided into four phases: first, the goal and scope of the product assessment are defined as well as, the context, the boundaries and the environmental indicators. Then, Life Cycle Inventory (LCI) comprises the compilation and quantification of the input (energy, material) and output flows (emissions, wastes), for all the processes related to the lifecycle of the product under investigation. In the impact assessment phase, these flows are converted into ecological effects such as global warming potential, abiotic depletion, human toxicity and finally compared with the objective.

LCA represents an assessment and comparison tool for existing products [START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF][START_REF] Janin | Ecodesign approach in company -A stake: building a coherence between tools and design process[END_REF]. It assists decision-makers in industry by identifying opportunities for improving the environmental performance of a product and can also help governments and non-government organizations by the implementation of eco-labeling [START_REF] Eigner | A Concept For An Intuitive And Interactive Fully Plm-Integrated Eco-Efficiency Assessment In Real-Time[END_REF]. However, it is complex and requires expertise and it's also both time and resource consuming due the large amount of accurate data needed to perform it [START_REF] Morbidoni | Enabling an efficient SLCA by interfacing selected PLM LCI parameters[END_REF][START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF]. We identified three LCA limits and some propositions to overcome them:

• LCA is not applicable in the early stages of design Many existing tools based on LCA fail because they do not focus on design, but instead, they are set to a strategic management or a retrospective analysis of existing products [START_REF] Morbidoni | Environmental Evaluation From Cradle To Grave With Cad-Integrated Lca Tools[END_REF]. A complete LCA can only be correctly used for a completely defined product where data about lifecycle are available and accurate. This data collection is also time-consuming. So LCA cannot be properly used in the early stages of design phases where many alternatives are studied and product lifecycle data are incomplete. To enable early application as well as to improve overall use of LCA within design, less complex and data demanding, Simplified Life Cycle Assessment (SLCA) have been developed [START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF][START_REF] Janin | Ecodesign approach in company -A stake: building a coherence between tools and design process[END_REF][START_REF] Rio | Toward proactive (eco)design process: modeling information transformations among designers activities[END_REF]. The simplification is related to data reduction either by excluding a lifecycle stage (use or end of life) and/or by reducing the complexity of the Life Cycle Inventory [START_REF] Morbidoni | Enabling an efficient SLCA by interfacing selected PLM LCI parameters[END_REF]. Then, it could be a source of error if it is not well parameterized or used by non-experts. So SLCA lowers the level of consensus among the scientific community because reducing the data inputs increases the level of uncertainty [START_REF] Eigner | A Concept For An Intuitive And Interactive Fully Plm-Integrated Eco-Efficiency Assessment In Real-Time[END_REF]. However, some method exist to manage the data quality of the inventory such as Pedigree Matrices [START_REF] Segonds | Collaborative Reverse Engineering Design Experiment Using PLM Solutions[END_REF][START_REF] Dufrene | An engineering platform to support a practical integrated eco-design methodology[END_REF] which allow an easy identification of the inventory weaknesses. It is then possible to improve its quality by directly working on these data. SLCA estimates the environmental impacts of design alternatives according to product characteristics such as the type of material or the weight. Thus, SLCA method reduces the time necessary to run the LCA [START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF][START_REF] Cluzel | Eco-design implementation for complex industrial systems Mise en oeuvre de l'éco-conception pour des systèmes industriels complexes[END_REF] and makes it usable in design process to evaluate different alternatives.

• LCA do not lead to eco-designed solutions LCA needs expertise especially to define the scope of the study or the relevant environmental indicators, and review their reliability. Designers have some difficulties to interpret the environmental results and to identify the product improvement areas [START_REF] Millet | Intégration de l'environnement en conception: l'entreprise et le développement durable Integration of environment in design process: Company and sustainability[END_REF]. This can be due to the lack of correlation between the environmental impacts and the product designer parameters such as material or manufacturing process [START_REF] Rio | Toward proactive (eco)design process: modeling information transformations among designers activities[END_REF]. If designers cannot use the method or interpret its results, the product cannot be eco-designed. Thus, it's important to create tools for non-expert users. That will to provide indicators which help designer to identify what product characteristics are the source of an impact in order to lead to eco-designed solutions. Then, human oriented interface is recommended [START_REF] Eigner | A Concept For An Intuitive And Interactive Fully Plm-Integrated Eco-Efficiency Assessment In Real-Time[END_REF]. The result indicators should be structured and flexible in a way to obtain easily selective, relative, absolute and environmental information linked to product characteristics.

• LCA is not adapted for a global corporate vision

When companies need to establish carbon footprint report that includes its product, eco-labels on their products or engaging continuous improvement actions [START_REF] Cluzel | Eco-design implementation for complex industrial systems Mise en oeuvre de l'éco-conception pour des systèmes industriels complexes[END_REF], they first need a reliable environmental assessment of the whole product portfolio. But, LCA is both time and resources consuming and thus not usable for global portfolio assessment. The central problem for sustainable business alignment is to analyze, to optimize and to communicate on product portfolio with the least effort [START_REF] Eigner | A Concept For An Intuitive And Interactive Fully Plm-Integrated Eco-Efficiency Assessment In Real-Time[END_REF]. It is then necessary to find a way to perform global environmental assessments with limited resources at an acceptable quality level [START_REF] Cluzel | Eco-design implementation for complex industrial systems Mise en oeuvre de l'éco-conception pour des systèmes industriels complexes[END_REF]. The intelligent use of existing digital databases as PLM, ERP systems, design tools and a good supplier relationship may streamline the data collection to obtain explicit and tacit environmental knowledge [START_REF]ISO 14001 -Environmental management systems: Requirements with guidance for use[END_REF][START_REF] Janin | Ecodesign approach in company -A stake: building a coherence between tools and design process[END_REF]. The table 1 compares LCA and SLCA on selected criteria. SLCA seems to be a good compromise to overcome most of LCA limits. The main challenges are to reduce complexity of product and portfolio data collection (inputs) and the indicators comprehension (outputs), while maintaining the main features and accuracy of a complete LCA. Then, it is important to study:

• Inputs: what type of information is required and how this could be collected.

• Outputs: what kind of results should be produced to help designers and how to manage their accuracy?

One way to simplify data collection is to connect SLCA with design tool as CAD or PLM system where product characteristics are included. Connection with ERP will then provide a global vision of the product portfolio.

Connecting PLM to environmental assessment tool

The results of industrial surveys identified CAD Geometric models as data reference, CAD, PLM and PDM systems as the most used tools during the design phase [START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF]. PLM is an approach in which processes are as important as data, or even more [START_REF] Segonds | Collaborative Reverse Engineering Design Experiment Using PLM Solutions[END_REF]. Thus, many authors agree that PLM is the key concept for the establishment of eco-design processes [4-6, 14, 27, 28]. The opportunity to influence a product's sustainable characteristics is prevalent in the design phase. The connection between PLM/CAD and sustainability might provide useful insights to a sustainable new product development approach [START_REF] Gmelin | Determinants of a sustainable new product development[END_REF]. This connection should be bi-directional [START_REF] Gmelin | Determinants of a sustainable new product development[END_REF][START_REF] Rio | Toward proactive (eco)design process: modeling information transformations among designers activities[END_REF]. PLM supplies the necessary data for an LCA, which then ensures and evaluates the environmental character of a product. Different interoperability approaches have been studied to connect environmental with design tools. These can be defined following three distinct points of view [START_REF] Segonds | The use of early design tools in engineering processes: a comparative case study[END_REF]: integration, unification and federation. System structure will be easier to evolve on a federative way than on an integrative one, if one of the tools have to change [START_REF] Rio | Toward proactive (eco)design process: modeling information transformations among designers activities[END_REF]. This connection between environmental and design tools is one of the emerging challenges that design software companies, like Dassault Systèmes, have to face [START_REF] Theret | Integrating CAD, PLM and LCA: new concepts, data model, architecture & integration proposals[END_REF]. Here below are described existing software with their main functionalities and limits:

• Module in CAD tool: Sustainability in Solidworks by Dassault Systèmes [29]

It's an SLCA module integrated into CAD Solidworks. The user can choose the material and the main process so the tool will calculate environmental indicators.

However, it's often criticized because of its low accuracy [START_REF] Luttropp | EcoDesign and The Ten Golden Rules: generic advice for merging environmental aspects into product development[END_REF][START_REF] Millet | Intégration de l'environnement en conception: l'entreprise et le développement durable Integration of environment in design process: Company and sustainability[END_REF]. Morbidoni et al. proved its weakness comparing its results with those of a specialized tool [START_REF] Morbidoni | CAD-Integrated LCA Tool: Comparison with dedicated LCA Software and Guidelines for the Improvement[END_REF].

• Information transfer PLM (SmarTeam) -Environmental tool (EIME) [START_REF] Mathieux | Product ecodesign and materials: current status and future prospects[END_REF] Compared to CAD, various relevant information can be extracted and imported from PLM into LCA software (mass, material, process, location…) [START_REF] Mathieux | Connecting CAD and PLM systems with ecodesign software: Current experiences and future opportunities[END_REF]. It's also flexible since PLM data transfer can be customized according to the product context. However, only few studies explain how to customize and formalize the necessary information for accurate LCA [START_REF] Rio | Toward proactive (eco)design process: modeling information transformations among designers activities[END_REF] and it doesn't include global reporting.

• PLM / CAD / ERP / environment platform: Environmental Data Workbench

It is an integrative platform based on central standard model that connects design (PLM, CAD), ERP and environmental tools [START_REF] Rio | At the interface of engineering and environmental analysis: federation for proactive eco-design[END_REF][START_REF] Theret | Integrating CAD, PLM and LCA: new concepts, data model, architecture & integration proposals[END_REF]. It is able to create global corporate report such as material compliance or carbon footprint as well as "product environmental profiles". However, the environmental data are decontextualized since the link between environmental results and design parameters is lost.

• Knowledge transformation between design and environmental tool

This solution proposed by Rio et al. [START_REF] Rio | Toward proactive (eco)design process: modeling information transformations among designers activities[END_REF] is a federative system with flexible data exchange (knowledge transformation) between design and environmental tools used during the design process. It also keeps the link between design and environmental parameters. However, the formalization of the necessary information for reliable evaluation has not been studied.

Existing solutions limits

A synthesis of existing solutions based on the criteria defined in paragraph 2.1. is presented in Table 2. However none of these tools or methods gives a reliable and time efficient product portfolio assessment.

Existing models prove the relevance of connecting SLCA with PLM system for eco-design and product portfolio assessment when connected with ERP system. However, few studies discussed the customization of the PLM which take into ac-count the reliability of results, which also have to be usable by designer to lead to eco-designed solutions. In the following, we propose a methodology to customize PLM and connect it with SLCA tool and ERP system for (1) An environmental assessment in the early stages of design process. ( 2) Meaningful results without weighting on product design time: this will lead to trade-offs between reliability of SLCA results and the information that the design team has to provide. (3) Ensure that environmental factors remains manageable and environmental potentials for a product can be identified and influenced early. (4) A time efficient product portfolio assessment and reporting.

Proposed methodology and architecture

In order to connect PLM with SLCA tools and ERP system, we propose a four steps methodology (Figure 1).

• Planning

According to the environmental strategy of the company, the objectives of the assessment are established such as carbon footprint reduction or product labeling. This will define the scope of the assessment, the relevant environmental indicators and their level of accuracy, as well as the methodology to calculate them. A preliminary analysis of existing database and tools containing product lifecycle information (transport, sales, markets…) is recommended. Applying a complete LCA on some products could help to determine the relevant lifecycle stages. The system operators (users, administrators…) and system development team are defined. According to the objectives and the available data, the assessment scope can consider a part of the product portfolio and limit the lifecycle stages included. This planning step is an important input of the system design.

• Definition of required elements

For reliable results without compromising product design time, the level of information required is defined. It has to limit the amount of additional data that designers provide. The indicators depend on the objective and strategy. The results must be structured in a way to be usable by designers and decision makers. Uncertainty indicators can be used for decision-making. These results have to be duplicated and stored in the PLM as report to avoid computing time for global assessment.

• System specifications and development

Once inputs and outputs are outlined, this step defines the functional and technical specifications of different parts, modules and interfaces of the PLM system.

• Deployment of the eco-design

Creation of the tool is not sufficient. Relevant KPI, involvement of all design team and adapting the design process are also important to lead to eco-design.

A synthesis of this methodology is presented in Figure 1.

The architecture resulting of the methodology deployment in an industrial luxury industry is an environmental assessment system able to deal with information already available in the PLM. We present it in the Figure 2. This architecture is based on three pillars: ERP, PLM and environmental expert tool. It can provide, thanks to SLCA module included in PLM, an environmental assessment at the early stages (filled arrow) or global assessment and reporting when connected with an ERP (empty arrow).

Case study

The methodology, previously described has been deployed in the context of packaging development in a luxury brand. This company is implementing Teamcenter PLM system of Siemens and the SLCA is a part of it. It should be underlined that Siemens integrates for the first time environmental assessment in their PLM system. This method has been conducted until the specification phase (Figure 1). First, the aim of this integration is determined according to company's strategy. This will help the company to achieve different goals such as: Allowing new product eco-design by providing "usable" and reliable environmental assessment results at the early stages of the design process; answering to a potential environmental labeling program in discussion in the French and European scope, carbon footprint calculation, material compliance (REACH, RoHS…) and allowing a global vision of product portfolio to enhance improvement actions; system operators (users, administrators…) and system development team are defined to consider user's needs as well as IT and environmental constrains. Three complete LCA have been performed on three products and show that packaging is the main contributor on the selected indicators and helped to choose the relevant lifecycle stages. Regarding the scope, the products portfolio covers all the samples, tests, gifts and sales products. Only the packaging is taken into account and the formula is not yet included. This is about 1.600 references and more than 12.000 different parts. The lifecycle stages covered by the assessment are: Material extraction, manufacturing process, transports and end-of-life. The use phase and conditioning are not included since the formula is not yet considered

Definition of required elements

Some representative products are selected to run Life Cycle Assessment: typology, manufacturing technologies and suppliers. These analyses helped to define how the results should be presented to be usable. Besides, lifecycle inventories have been performed for each product to identify the environmental hotspot.

Required results. The environmental indicators should be adapted to objectives that companies have to fulfill such as carbon footprint or product labeling. As consequence, the environmental assessment needs to be connected directly (or indirectly) to the ERP in order to link individual product impact with the sales quantities (information not available in the PLM). At least three different environmental indicators need to be calculated for the product labeling abiotic depletion, water consumption and global warming potential. This latter indicator must be calculated in two different ways: the first for the product environmental labeling and the second for carbon footprint. These results will help designers to find areas of improvement for eco-design. So, the interface needs to give a strong detail of the origin of the environmental impact: component, lifecycle stage and the most important sources of impacts as well as total results with uncertainty indicators for decision-making. It is semi-quantitative to avoid computing time and rely on Pedigree matrices [START_REF] Segonds | Collaborative Reverse Engineering Design Experiment Using PLM Solutions[END_REF][START_REF] Dufrene | An engineering platform to support a practical integrated eco-design methodology[END_REF].

Required inputs for relevant LCA. In order to define the relevant level of information and data collection required, we perform different studies. The company has chosen to create a specific SLCA tool to perform their studies and use it pending the PLM development. All these assessments allow drawing some rules and defining data that need to be taken into account in order to have a relevant result. These data, as material weight, was not already completely included in the PLM. Discussions in system development team leads to find the best way to integrate them without compromising data collection time, for example:

The part weight: The detailed weights were not capitalized by the design team while it is really important to evaluate environmental impact of manufactured parts. It has been added in the design interface for each element. This data could not be extracted automatically from other company's tools, so designer will enter it manually as CAD tools are not used internally.

Country where the part is processed: Accurate evaluations need the electricity mix: The impact of producing 1 Kwh which varies according to the country. We decided to get it indirectly from "supplier reference table" where the country will be informed. So the evaluation will be more precise without any consequence on the designer interface where only plant name will be selected.

System specifications and development

According to the input/output and the objective, the functional and technical specifications of the system are created. Modules, interfaces, referential, databases, information flow, calculation algorithm and data management are specified in order to collect all relevant data to perform SLCA at different stages of design phase. Validation is necessary on a case study before the launching for software development. The experimentation is currently in this phase. Once the software is ready it will have to be tested before the integration in real work environment.

Conclusion and perspectives

This article proposes a methodology and an associated architecture to connect PLM, SLCA and ERP in order to eco-design new products and get easily a product portfolio assessment. The necessary data for accurate results have been identified through several LCA studies on representative products. A qualitative indicator on reliability results has been set. The system results keep the link between the environmental impact and their sources from products characteristics in order to identify improvement areas. This methodology has been conducted as part of a project to implement Teamcenter PLM system in a luxury company for packaging products. This is a first time Siemens integrates environmental assessment in their system. It's currently in the specification phase and will be soon integrated. Other environmental tool will be considered as packaging recyclability indicators and specific guidelines-checklist. A further work could compare the results of the proposed evaluation system with complete LCA in order to find improvements. This methodology could also be enriched by including new functionalities to improve data collection by connecting CAD tools, web platform to collect data from suppliers and different design tools.

Fig. 1 .

 1 Fig. 1. Proposed methodology

Fig. 2 .

 2 Fig. 2. Architecture to connect SLCA with PLM and ERP System

Table 1

 1 Comparative between LCA and SLCA

	Criteria	LCA SLCA
	Usable in early design phases	-	+
	Lead to eco-design solutions	-	+
	Results reliability	+	0
	Global portfolio assessment	-	0

Table 2

 2 Comparative between different existing solutions

	Criteria/System	Solidworks	Smarteam	EDW	Knowledge
		Sustainability	EIME		Transformation
	Usable in early design phase	+	+	+	+
	Lead to eco-designed solutions	+	+	-	+
	Results reliability	-	0	+	0
	Global portfolio assessment	-	-	+	+

Forest Stewardship Council: sustainable label for wood-based products, www.fsc.org


Akio Kamoshita
email: akamoshijp@gmail.com

Hiroyuki Kumagai

A Study for Building a Comprehensive PLM System Based on Utilizing the Japanese Strength of Industry

Keywords: Product Development Process, 3D Digitization, Design and Manufacturing, Product Design Architecture, Organizational Capability, Process Optimization, Product Globalization, CAD, CAE, PDM, BOM, PLM

Keeping "the Japanese Strength" in digitizing the process of product development is important for the Japanese industry to survive in the intensifying global competition of market. This paper researches about the way of building a comprehensive PLM system based on "the Engineering Process Integrated Architecture (EPIA)" to realize it by taking up actual cases. The system, based on integrated database, consistently integrates the whole process of product planning, development and design, manufacturing preparation, production, purchasing, sales, service and maintenance, and it enables the mutual cooperation of the information of PLM/SCM/CRM.

Introduction

Keeping "the Japanese Strength" in digitizing the process of product development is important when a PLM system is built. If you look at the characteristics of product development in terms of "product architecture", "manufacturing organizational capability" and "design and manufacturing process", it is necessary to connect them based on the "digital data standards" in the PLM system construction. Among them, the strength of Japan, in particular, is in a tight connection with the "manufacturing organizational capability" and "design and manufacturing process", and it has a feature that allows for flexible system operation. (Fig. 1) [START_REF] Fujimoto | Manufacturing business administration[END_REF], [START_REF] Youngwon | Integral Type of Manufacturing and IT system-Suggestion of the framework of the IT utilization to bring competition predominance[END_REF] In this paper, based on taking up actual cases, we study a comprehensive PLM system construction which integrates consistently the whole process of product planning, development and design, production preparation, production, procurement, sales, service and maintenance. The system will become important in the future, in the digitization of the product development process to utilize the Japanese strength of industry, in the intensifying global competition market.

Development history of the PLM system

2.1 To a mutual cooperation system from a individual system PLM systems that support the actual business of product development was first constructed in the individual work of each department. Then, it has been built consistently, from the design and development work of the upstream process, in turn manufacturing arrangements, production process, etc. Among these, the system is constructed as to allow cooperation between departments adjacent individually.

At present, by globalization of manufacturing industry, localized production and purchasing has progressed, the needs to send the local information to upstream process is increasing. To respond to such needs, there has been seen such a case for feeding back information to the upstream process from the downstream process, by building a system of mutual cooperation between business, based on an integrated database. (Fig. 2)

Design concept of the cooperative system

In the intensifying competitive global market, to take advantage of the strengths of product development of Japan, the spiral cooperation in the design development and manufacture is the key, that is made of not only a top-down approach from the upstream Fig. process of Western thought but also made of a bottom-up approach from the production site of Japan. In order to strengthen it, in the digital development of the Japanese manufacturing industry in the future, it should be aimed at to build a PLM system by an architecture that enables the consistent conjunction of information with assembly process BOM and manufacturing BOM in the downstream process along with the control of CAD, PDM and design BOM in the upstream process. (Fig. 3) [START_REF] Nakamura | Ultimate form of the global production to extend the manufacturing power in Japan[END_REF]

MRP MRP MRP MRP----

A A A A MRP MRP MRP MRP--- -B B B B MBOM MBOM MBOM MBOM 【 【 【 【M M M MBOM BOM BOM BOM】 】 】 】 ・ ・ ・ ・Global Solution Global Solution Global Solution Global Solution ・ ・ ・ ・Master/ Master/

Expansion into a comprehensive PLM system 3.1 The concept of a comprehensive PLM system

Up to the previous section, a desirable PLM system has been shown from the globalization point of manufacturing preparation, production and procurement process. In the future, the system construction which hold the entire life cycle of a product as consistent process becomes important for promoting the "manufacturing innovation". The system includes not only the current process of design development, manufacturing preparation, production and procurement, but also the upstream process of the product planning, and the downstream process of sales, service and maintenance. A design concept in this system building, "Engineering Process Integrated Architecture (EPIA)" is shown in FIG 4. [START_REF] Youngwon | Integral Type of Manufacturing and IT system-Suggestion of the framework of the IT utilization to bring competition predominance[END_REF] The representation put the time axis within each process axis is shown in Fig. 5. In each process axes, depending on the progress of each process, data related to the product is stored and updated in the integrated database. Further, the data linkage performed by each arrow between each process axes is also performed through the integrated DB. The data is feed-forward between the virtual process and the real process, and feed-back as the same. Similarly, the data is feed-forward between virtual process and field process, and feed-back as the same. In order to perform the close communication between organizations involved in each process, the Japanese "manufacturing organizational capability" is easily allow this data linkage. The following describes the concept by which in turn take up the actual cases.

Cooperation with the manufacturing site information and planning and design information (Data linkage between the virtual process and the real process)

By using a digital mock-up, feed-forward and feed-back to the design by the production site information are performed by the design study of interference gap and operability etc. and by the productivity study of assembly and maintenance operation and the like. Further, by using a simulation, a similar function is performed by the performance study of design strength and heat resistance and so on.

In the product development of Japanese companies, this has been done through the teamwork of people at manufacturing sites and design, by sharing information with the drawings. Now, it came to be organized as (simultaneous) concurrent engineering, information cooperation by the system is carried out.

In recent years, the case that production site and design site is separated geographically is increasing. Originally, innovation of the product is realized based on awareness by trial and error in the site of production, by devising a new knowledge through teamwork of design and production. In terms of taking advantage of the strengths of Japan, cases such as the following are desirable.

A case of the automotive industry

Toyota Motor Corporation says that new products and new technology are born from Japan with strong manufacturing site, high technology and a high-performance material. Therefore, competitive edge is in the domestic plant. In order to deploy the car of high quality into the factory of the world, to enhance the technology to produce low-cost in a short period of time, it is necessary to strengthen the mother plant in Japan (Iwate Prefecture, etc.). To do so, to carry out business as minimum, it is required domestic production of 3 million units in the maintenance of the pyramid structure of the domestic business.

A case of electrical precision industry

In the production of notebook / Tablet PC, in order to suppress the domestic labor costs, Fujitsu limited promote automation (robotic) of the assembly process. Thereby, synergy to co-exist manufacturing and production operations, and design and development is prioritized. (Fig. 6)

A case of heavy machinery industry

The characteristic of production and development system of Komatsu is coexistence of production and development department at all plants. Thereby a strong cooperation of both sectors is promoted. The key components that give a competitive advantage to competitors are developed and manufactured only in Japan. There is a mother plant in Japan in each product group, child factory carries out the production and development in a place close to the market. As a result, the building-cost and product quality, product development that meets the market needs are carried out.

Sophisticated use of information in planning and design of upstream

process (Data linkage between the virtual process and field process)

Sophisticated product planning method

In recent years, with the progress of globalization, the need of information required in the planning stage of product development is increasing to include production, purchasing and marketing from those around the product so far, i.e. where to buy, where to make, where to sell, where to make money, how to maintain? In this respect, feed-forward and feed-back of information of market and services and maintenance to the design and marketing has become more important. The following is one of the advanced cases of product planning. Quoted from reference [START_REF] Ogawa | Drivetrain System Design Based on an Architecture Analysis Method[END_REF] been developed by Nissan Motor Co., Ltd. The complexity of the product architecture is assessed multilaterally by architecture analysis from the upstream planning stage to downstream stage.

And, implicit knowledge (know-how) of the design process that veteran designers have is transformed to explicit knowledge. [START_REF] Ogawa | Drivetrain System Design Based on an Architecture Analysis Method[END_REF] As shown in Fig. 7, the matrix of performance items and specification items (QFD matrix) that make up product architecture is prepared in size in accordance with the purpose of each development phase. In each phase, to determine the order in which they evaluate the degree of influence performance, specifications, and decide by priority of having a large impact. At this time, an efficient procedure is obtained by sorting of logical priority, and also by weaving know-how that is based on past experience. A consensus of the decision-making of each phase including especially difficult upstream processes is facilitated while incorporating the implicit intellectual approach of Japan.

A case of electrical precision industry

White home electric appliances for emerging countries

In the Panasonic Corporation, volume segment products in the global, are positioned as strategic products in order to capture the emerging countries, and are classified into three categories. One is "leading global V" products intended to be sold to wealthy emerging countries, the value-added products that are popular in Japan and other developed countries. The second is products that fight head-to-head with other companies in the main battlefield of the global. Using a common base model, expand in multiple countries, it aims to increase market share in each country. The third is products developed by the idea of local market, in order to capture the middle layer of emerging countries.

Currently, Lifestyle Research Centers and equivalent organization are established in five countries, that is China, India, Brazil, Germany, and Vietnam. A mechanism has been built to create a product equipped with the functionality required for different countries by visiting to the country site actually to investigate the actual use.

Collaboration with field information

A case of heavy machinery industry

Meanwhile, In Komatsu Ltd., there is the case to enhance the more competitiveness of the product by utilizing market information, service and maintenance information, when the product is used in the market. By having a guideline of component replacement and maintenance time through the grasp of the actual usage in the market, they take advantage of the collaboration with production and parts procurement, and improve the quality of attractiveness by reflecting on the design specifications during product planning. (Fig. 8) [START_REF]company information, service solution[END_REF]

Manufacturing organization capability of Japan to support the comprehensive PLM system construction

Here, the Japanese "manufacturing organizational capability" will be discussed. By performing a close communication between organizations, it allows in product development in Japan, the tight linkage of data between processes.

Characteristics of design information management in Japan

An overview of the differences of Japanese-style and Western-type is shown in Fig. 9 regarding the management method of design information in product development.

In the Western method, the information that is determined by the design is deployed by top-down in one direction to each relevant departments of the next step. In contrast, in the method of Japan, the information which is determined by the design, and is received feedback from each department, is deployed as the information that has been refined mutually in both directions. As shown in this figure, the management method of Japan has good compatibility with such as product development involving many technical elements, and especially with integrated products that require close cooperation of the data It is because it works by compromise, while allowing the ambiguity, and incorporating the diverse opinions of many stakeholders including the manufacturing site.

Characteristics of organizational culture of Japan

And also regarding the organizational culture, an overview of the differences of Japanese-type and Western-type is shown in Fig. 10.

As shown in the table, it has the characteristics focusing on more bottom-up consensus in team play than personal top-down leadership.

Hence, as mentioned above, tight linkage of data for managing the product development information is done naturally. Such as shown above, the characteristics of the Japanese "product development organizational capability" is considered to be intended to support the comprehensive PLM system construction. It should be noted that, at the time of comprehensive PLM construction, improving the weaknesses by emphasizing consensus is required, while following the strengths of Japan that has been demonstrated so far. For this purpose, the measures indicated by the arrow in Figure, is desirable to be reflected in the ICT design platform.

Direction of the comprehensive PLM system construction in the globalization of industry

In the preceding description, in the industrial globalization, comprehensive PLM system construction to utilize the strengths of product development of Japanese companies is essential. Here, a direction of it is shown based on actual cases of PLM construction in the electric precision industry and the automotive industry in Japan.

A case of automotive industry

In the automotive industry, according to the vertically integrated production structure, an industry pyramid is created in each region, and the core functionality of development and manufacturing, is located in Japan. The Planning, development and design by the OEM at the pyramid top is done in cooperation with other countries and Japan headquarters, and Teir1 below also has cooperation with local site and head office.

In this case, with respect to PLM tool, it is necessary to use a system of the same type as the OEM, or to use a system that does not have a problem on data distribution. Feedback to the design of information from production preparation, procurement and construction can be understood for carrying out product development to meet the market needs, in the two-way information cooperation of production site and development and taking advantage of the product development of Japan.

Conclusion

In this paper, for the sake of global expansion of Japanese industry, as a mechanism of information utilization to take advantage of the product development of Japan, a comprehensive PLM system based on a system architecture named as "Engineering Process Integrated Architecture(EPIA) is discussed by taking up the actual cases. The system, based on the integrated data base, consistently integrates the whole process of product planning, development and design, manufacturing preparation, production, purchasing, sales, service and maintenance. And also it enables the mutual cooperation of the information of PLM/SCM/CRM.

When the manufacturing industry of Japan performs the process reform to build a system based on this idea, it is possible to perform global deployment by leveraging the strengths of product development in Japan, drawing a line from the global expansion of Western industry.

Fig. 3

 3 Fig.3 Architecture of integrated PLM system

Fig. 4

 4 Fig.4 Engineering Process Integrated Architecture

Fig. 5

 5 Fig.5 Process Axes & Data linking of Each Process Axis

Fig. 6 Synergic

 6 Fig.6 Synergic Effects of Development and Manufacturing Dept.

  Fig.7 Method of Defining Product architecture for Each Dev. Phase

Fig. 8

 8 Fig.8 Corresponding to the Market by Utilizing Field Information

Fig

  Fig.9 Feature Comparison of Design Information Management

Fig

  Fig.10 Characteristics Comparison of Organizational Culture

2 Growth history of PLM system

		System Pattern System Pattern System Pattern System Pattern		Remarks Remarks Remarks Remarks
						・ ・ ・ ・Phase Based Optimization Phase Based Optimization Phase Based Optimization Phase Based Optimization
	Sectional Sectional Sectional Sectional	3DCAD 3DCAD 3DCAD 3DCAD DMU DMU DMU DMU	PDM PDM PDM PDM	EBOM EBOM EBOM EBOM PBOM PBOM PBOM PBOM MBOM MBOM MBOM MBOM	SCM SCM SCM SCM	( ( ( (Partial Optimization) Partial Optimization) Partial Optimization) Partial Optimization)
	Installation Installation Installation Installation					・ ・ ・ ・One way from upstream to One way from upstream to One way from upstream to One way from upstream to
						downstream downstream downstream downstream
	Divisional Divisional Divisional Divisional					・ ・ ・ ・Mutual Connections with neighboring Mutual Connections with neighboring Mutual Connections with neighboring Mutual Connections with neighboring
					SCM SCM SCM SCM
	Installation Installation Installation Installation				MBOM MBOM MBOM MBOM	sections sections sections sections
					PBOM PBOM PBOM PBOM
			EBOM EBOM EBOM EBOM
			PDM PDM PDM PDM
	( ( ( (ICT with ICT with ICT with ICT with	DMU DMU DMU DMU
	Process Process Process Process	3DAD 3DAD 3DAD 3DAD
					・ ・ ・ ・Glowth Glowth Glowth Glowth Each Each Each Each
	Connection) Connection) Connection) Connection)
	Mutual Mutual Mutual Mutual					・ ・ ・ ・Integrate allover the company Integrate allover the company Integrate allover the company Integrate allover the company
	Sectional Sectional Sectional Sectional					・ ・ ・ ・Enable to feed Enable to feed Enable to feed Enable to feed----back spread over the back spread over the back spread over the back spread over the
		3DCAD 3DCAD 3DCAD 3DCAD DMU DMU DMU DMU	PDM PDM PDM PDM EBOM EBOM EBOM EBOM PBOM PBOM PBOM PBOM MBOM MBOM MBOM MBOM SCM SCM SCM SCM
						sections sections sections sections
	Cooperation Cooperation Cooperation Cooperation
						・ ・ ・ ・Enable to the feed Enable to the feed Enable to the feed Enable to the feed----back from down back from down back from down back from down
						stream to upstream stream to upstream stream to upstream stream to upstream
	( ( ( (ICT with ICT with ICT with ICT with
	Integrated DB) Integrated DB) Integrated DB) Integrated DB)	・ ・ ・ ・Vertical Starting Up Vertical Starting Up Vertical Starting Up Vertical Starting Up		・ ・ ・ ・Reduce lead time Reduce lead time Reduce lead time Reduce lead time
	【 【 【 【 DMx DMx DMx DMx】 】 】 】	【 【 【 【 EBOM EBOM EBOM EBOM】 】 】 】		【 【 【 【 PBOM PBOM PBOM PBOM】 】 】 】
	・ ・ ・ ・ Multi CAD Data Multi CAD Data Multi CAD Data Multi CAD Data	・CAD ・CAD ・CAD ・CAD/ / / /DMU DMU DMU DMU		・ ・ ・ ・ Synchronous Release Synchronous Release Synchronous Release Synchronous Release
	Management Management Management Management	Cooperation Cooperation Cooperation Cooperation		・ ・ ・ ・ Process/Production Process/Production Process/Production Process/Production
					Design Design Design Design
							・ ・ ・ ・Own Plants Own Plants Own Plants Own Plants
	CAD CAD CAD CAD----A A A A	Cooperation Cooperation Cooperation Cooperation	Integrated PLM Integrated PLM Integrated PLM Integrated PLM
							( ( ( (ODM/EMS ODM/EMS ODM/EMS ODM/EMS) ) ) )
		DMx DMx DMx DMx
	CAD CAD CAD CAD----B B B B
					Cooperation Cooperation Cooperation Cooperation		・ ・ ・ ・ Global Global Global Global PSI PSI PSI PSI
		BOM BOM BOM BOM----A A A A				Global Global Global Global
							・ ・ ・ ・ Monitoring Monitoring Monitoring Monitoring
			EBOM EBOM EBOM EBOM
						Master Master Master Master
		BOM BOM BOM BOM----B B B B
						・ ・ ・ ・Multi Language Multi Language Multi Language Multi Language	・ ・ ・ ・ MRPs MRPs MRPs MRPs
			DMU DMU DMU DMU
					PBOM PBOM PBOM PBOM	・ ・ ・ ・Multi Currency Multi Currency Multi Currency Multi Currency
				MPM MPM MPM MPM	・ ・ ・ ・Global Time Global Time Global Time Global Time

Plant Plant Plant Plant

Quoted from reference [START_REF]company information, service solution[END_REF] production is carried out in each layer of the Tier; a smooth cooperation with the Japanese headquarters of each layer is one of the most important issues.

Hereafter, along with the development of the modular design of an automobile, global procurement of general-purpose products is carried out. For the PLM tool, a product of an open architecture having a higher degree of freedom increases the more importance in the product development of each company.

A case of electrical precision industry

Unlike the automobile, there is no pyramid structure of Tier; there is a horizontal specialization structure in which headquarters make procurement of general-purpose goods. The core functionality of development and manufacturing is located in Japan. Although production bases are deployed globally, the sourcing is concentrated in Japan headquarters. In that sense, in response to the globalization of product markets, production bases are located globally, planning and development functions does not moved, and each research site is placed in each market. (Fig. 12)

In this case, PLM tool is a separate product for each part of each company. If necessary, assembly products manufacturer make design consideration by preparing data of the components for their own system. Feedback to the design of information from production preparation, procurement, and production is needed to be carried out direct and quickly to the headquarters. But the size of the spatial-temporal distance is increasing the difficulty of cooperation.

Future, since production bases movement, and speed up needs of procurement and production information F / B, the domestic production by returning to Japan is also considered. PLM system is required to have flexibility against such base movement.


Martin Eigner

Thomas Dickopf
email: thomas.dickopf@mv.uni-kl.de

Hristo Apostolov

Patrick Schaefer

Karl-Gerhard Faisst

Alexander Kessler

Karl-Gerhard Faißt

Alexander Keßler

System Lifecycle Management: Initial Approach for a Sustainable Product Development Process Based on Methods of Model Based Systems Engineering

Keywords: System Lifecycle Management, Model Based Systems Engineering, Sustainability, Traceability

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Contemporary technological products are multi-disciplinary systems developed by multiple engineering disciplines. The risen requirements on these systems led to a complexity explosion, especially with regard to the information flow within the product development process [START_REF] Eigner | Product Lifecycle Management -Ein Leitfaden für Product Development und Life Cycle Management[END_REF]. As a result of new upcoming legislation focusing on sustainability, complexity is increasing furthermore [START_REF] Azevedo | Modeling Sustainability of Complex Systems -a Multi-scale Framework using SysML[END_REF]. But, in parallel to the challenges arising, great opportunities are also evolving for manufacturing companies to make their contribution to the sustainability paradigm and to gain advantage over their competitors through ecologically, economically and socially motivated system and process innovations [START_REF] Bras | Incorporating Environmental Issues in Product Realization[END_REF] [START_REF] Barreto | Product Lifecycle Management in Support of Green Manufacturing -Addressing the Challenges of Global Climate Change[END_REF]. A multi-disciplinary system development requires a rethinking of common methods, processes, IT solutions and organizational forms as known in product development today. To cope with complexity and to assure fulfillment of new requirements, traceability throughout the entire system lifecycle is needed. Today, traceability in a Product Lifecycle Management [START_REF] Eigner | Product Lifecycle Management -Ein Leitfaden für Product Development und Life Cycle Management[END_REF] [5] solution manifests itself only in relations defined between product requirements and elements of the bill of material.

This paper considers System Lifecycle Management [START_REF] Eigner | Modellbasierte Virtuelle Produktentwicklung auf einer Plattform für System Lifecycle Management[END_REF] as a key concept for the definition of engineering design processes. Model Based Systems Engineering (MBSE) [START_REF] Eigner | Modellbasierte Virtuelle Produktentwicklung auf einer Plattform für System Lifecycle Management[END_REF] [START_REF] Paredis | Why Model-Based Systems Engineering? -Benefits and Payoffs[END_REF], as essential part of the System Lifecycle Management concept, is a multi-disciplinary engineering paradigm to guide the design process in the early phases and to achieve traceability. In this paper a new approach for a comprehensive system description based on an extended V-Model [START_REF]Design Methodology for Mechatronic Systems[END_REF] is presented. It constitutes a promising new instrument for functional system description helping to achieve a multi-disciplinary system development taking into account the environmental aspect of sustainability. The model builds upon work of the ERMA research project [START_REF] Eigner | Leveraging Product Development for a Sustainable Future -Energy and Resource Efficiency in Lifecycle Analysis[END_REF], which aims at proactive estimation of the eco-performance of future concepts of wheeled excavators.

Motivation and Objective

In the field of construction equipment, with well-established, mechanical, hydraulic, hybrid and electronic solutions, the need of eco-design will increase significantly because of further increase of energy costs, stricter energetic requirements and growing competitive pressure. The prospective view within ERMA [START_REF] Eigner | Leveraging Product Development for a Sustainable Future -Energy and Resource Efficiency in Lifecycle Analysis[END_REF] requires analysis of the wheeled excavator and the application of Life Cycle Assessment [START_REF]Environmental Management -Life Cycle Assessment: Principles and Framework[END_REF] [START_REF] Kloepffer | Oekobilanz (LCA) -Ein Leitfaden für Ausbildung und Beruf[END_REF] in a proactive manner supporting the product development. Extensive concepts and new structures, such as innovative and integrated technical solutions for increasing the total energy efficiency, are needed [START_REF] Finzel | Energieeffiziente Antriebssysteme mobiler Arbeitsmaschinen[END_REF]. New requirements on the product's sustainability and eco-performance as well as the demand for high flexibility lead to complex product systems which contain mechanic, hydraulic, electric and even hybrid subsystems [START_REF] Schindler | Eco-Efficiency Analysis for Hydraulic and Hybrid Concepts for Mobile Working Machines[END_REF]. Systems like the investigated wheeled excavator are characterized by a large number of constituent parts, complex processes and, referring to the lifecycle, a dominance of the usage phase due to high energy consumption throughout a long lifecycle [START_REF] Pickel | Life Cycle Assessment (LCA) and its Importance for the Agriculture Sector[END_REF] [START_REF] Kwak | Exploring Opportunities to Improve Life Cycle Environmental Performance of a Complex Product[END_REF]. The overall effect of energy and resource reduction through new technical concepts is often hard to predict, especially in the case of multi-disciplinary systems. To quantify these predictions is even harder. This leads to the need for a comprehensive system solution [START_REF] Bras | Sustainability and Product Life Cycle Management -Issues and Challenges[END_REF].

The results shown in figure 1 are based on the product structure, related manufacturing, transportation and distribution processes as well as an assumption for the usage phase. Regarding the lifecycle of a commercial vehicle more than 90% of the greenhouse gas emissions are resulting from energy consumption out of the usage phase. The paper is limited to an exemplary consideration of the usage phase as main driver of the environmental impact. It deals with the outlined problem of an early system description based on a dynamic view referring to specific behavior artifacts using the example of greenhouse gas emissions. Challenges for a sustainable development process are:

(a) Multi-disciplinary View on Complex Product Systems:

Current development processes of complex mechatronic products are heavily influenced by multiple disciplines like mechanic, electronic and informatics as well as dependencies between information elements and engineered system parts. System specification, modeling and first simulations are still discipline-specific.

(b) Lifecycle View on Complex Product Systems:

Beside the assessment of the used materials based on the product structure, a comprehensive consideration of all related processes, starting from raw material extraction to the end-of-life activities as well as all supporting processes like transportation, are of central importance in regard to sustainability.

An approach based on the methods of Model Based Systems Engineering can help to improve the traceability within complex multi-disciplinary systems throughout multiple lifecycle phases and thereby to identify the key areas to be targeted by an exemplary case scenario of the sustainable development process of a product system.

Related Work

To enable an early system description the new concept of System Lifecycle Management, with a proposed extension on the V-Model within, is a promising new instrument for functional description of a product system. In order to introduce an approach for exemplary sustainable product development process, the theses that are described in this paper build upon the previous work on sustainability assessment [ [START_REF] Eigner | Sustainable Product Lifecycle Management -A Lifecycle Based Conception of Monitoring a Sustainable Product Development[END_REF] and research on the topic of Model Based Systems Engineering performed at the Institute for Virtual Product Engineering (University of Kaiserslautern, Germany) [START_REF] Eigner | Proposal for Functional Product Description as Part of PLM Solution in Interdisciplinary Product Development[END_REF] [25].

2] [3] [18] [19] [20] [21] [22]

System Lifecycle Management

Up to 80% of the essential characteristics of each system are determined in the early phase of its development [START_REF] Eigner | Product Lifecycle Management -Ein Leitfaden für Product Development und Life Cycle Management[END_REF]. Decisions made here are fundamental for the entire lifecycle of the product system. Revising the system or changing processes in later phases causes great effort. System Lifecycle Management represents a concept rather than a monolithic IT system. Similar to Product Lifecycle Management [START_REF] Bras | Incorporating Environmental Issues in Product Realization[END_REF] [START_REF]Industrie 4.0 -Beherrschung der industriellen Komplexität mit SysLM[END_REF] is an integrated, informationdriven concept to improve the performance of a product system over the entire lifecycle. It achieves efficiency by using a shared information core system that helps engineers to efficiently manage complexity in the lifecycle of the product system from first definition of requirements to end-of-life activities. Thus, the concept does not provide innovative systems but can contribute to engineering at administrative level (see figure 2) by providing the right information at the right time in the right context. Definition: System Lifecycle Management (SysLM) is a general information management solution extending today's Product Lifecycle Management to the early phase and all disciplines including services. The concept is based on the direct or indirect (via TDM1 ) integration of various authoring systems along the system lifecycle with the technical-administrative backbone for system or product models and processes. All development phases and the resulting models (R,F,L,P, …2 ) of the system's lifecycle are included and connected to achieve traceability.

[5] [19] [22] [26], System Lifecycle Management [6]
As an exemplary extension to Product Lifecycle Management in regard to Eco-Design and sustainability [START_REF] Eigner | Product Lifecycle Management -Ein Leitfaden für Product Development und Life Cycle Management[END_REF] [3] [START_REF] Moeller | Eco Product Lifecycle Management[END_REF] [29] [START_REF] Feickert | Oekologisches Product Lifecycle Management -Ein Integrationskonzept der oekologischen Produktbilanzierung in betrieblichen ERP-Systemen[END_REF], System Lifecycle Management can help to improve the environmental and sustainability performance of a product system by achieving traceability with regard to the material flow, starting from extraction of raw materials, processing, production, manufacturing, storage, transport, usage and disposal. In addition, requirements traceability is realized over the entire development process. Within, the concept of Model Based Systems Engineering provides methods to guide the cross-disciplinary, virtual product development process and to achieve the required traceability.

Model Based Systems Engineering

Model Based Systems Engineering (MBSE) is a multi-disciplinary engineering paradigm propagating the use of models instead of documents to support analysis, specification, design and verification of the system being developed [START_REF] Friedenthal | A Practial Guide to SysML -The Systems Modeling Language[END_REF]. Systems Engineering as such, comprises technical but also management processes to generate a balanced system solution in regard to various stakeholder needs and to reduce risks that can hinder the success of a project [START_REF] Haskins | Systems Engineering Handbook -A Guide for System Life Cycle Processes and Activities[END_REF]. In the case of sustainability, this could be an early consideration of the usage phase. In the study introduced in this paper, by using models instead of documents, a discipline-neutral view of the system specification is created. The resulting coherent system model helps to understand and to overview the complexity of the developed system and, moreover, it simplifies the communication in the multi-disciplinary development team. Interdependencies between individual system components are managed; the system is kept consistent to the specification and satisfies all defined requirements. In this context, requirements traceability can be archived over the entire development process. In previous work done at the Institute for Virtual Product Engineering [START_REF] Eigner | Proposal for Functional Product Description as Part of PLM Solution in Interdisciplinary Product Development[END_REF] [25], a methodical guideline for the use of the Model Based Systems Engineering paradigm has been developed (see figure 3).

With regard to the V-Model from [START_REF]Design Methodology for Mechatronic Systems[END_REF], the extended V-Model enables a modelbased and structured system description on the left wing of the 'V' in the early design phases. The systemization on the left wing of the V-Model is used to describe the three levels of specification, first simulation and discipline-specific modeling. Parallel to these overlapping levels, the information artifacts or model elements are differentiated in requirements (R), functions (F), logical solution elements (L) and physical parts (P), which are modeled in authoring tools and languages. Through semantic links between different model elements, as well as between elements of the same type, traceability could be ensured from a 'horizontal' and 'vertical' point of view (see figure 3). 'Vertical' traceability is to be guaranteed by linking system elements hierarchically above different system levels. The allocation links between different model types (R-F-L-P) permit 'horizontal' traceability over the different system specification stages [START_REF] Eigner | Proposal for Functional Product Description as Part of PLM Solution in Interdisciplinary Product Development[END_REF]. New in this context is the consideration of behavior (B) within the system development (see figure 3). The behavior of the system and the user's behavior have high impact on the eco-performance regarded.

System models are created by application of the Systems Modeling Language (SysML). In addition, a specific data scheme describes and defines these elements as well as the semantic links between them. Furthermore, it allows integrating and managing the information in a System Lifecycle Management (SysLM) backbone.

Approach

Several solutions for sustainability assessment of product systems have been developed [START_REF] Romaniw | An Activity Based Approach to Sustainability Assessments[END_REF] [22] [START_REF] Ramani | Integrated Sustainable Life Cycle Design -A Review[END_REF] [34] but the subject is still not solved satisfactory. None of these solutions considers both of the introduced challenges in one joint and integrated approach. Following, an initial approach for an exemplary sustainable product development process based on methods of Model Based Systems Engineering is introduced.

Methodology to Include Behavior in the Early Development Phases

The V-Model from VDI 2206 [START_REF]Design Methodology for Mechatronic Systems[END_REF] defines a systematic methodology for developing mechatronic systems, but it is not addressing all aspects of model-based design. This gap between requirements engineering and the intellectual model of the product system has been closed by research [START_REF] Eigner | Modellbasierte Virtuelle Produktentwicklung auf einer Plattform für System Lifecycle Management[END_REF] [7] [START_REF] Eigner | Proposal for Functional Product Description as Part of PLM Solution in Interdisciplinary Product Development[END_REF] [25] within the RFLP-approach and the three layers of modeling and specification, specification and first simulation as well as discipline specific modeling on the left wing of the V-Model. However, the V-Model is not suited to model and maintain behavior such as the usage phase of a product system. An approach for the extension of the V-Model is depicted in figure 3.

The following steps describe the procedure of modeling behavior in the early design phases:

Step 1 -Identification of Key Drivers Following the RFLP Approach: In the first step the occurring gap between requirements and physical parts has to be closed. The outcoming traceability of structural elements along RFLP helps to identify the key drivers at an early level of development.

Step 2 -Specification of Behavior Artifacts in the Early Phase: Corresponding to the 'horizontal' traceability of structural elements in step 1, a 'horizontal' traceability of behavioral artifacts has to be specified, which allows a quantitative consideration of behavior from an abstract view at requirements level to a concrete description on the level of logical elements. Though this, the identified key drivers from step 1 could be observed in the context of their main functions.

Step 3 -Analysis of Behavior Artifacts in the Early Phase:

For a first calculation and simulation of system's behaviors in the early phases of development, it is needful to generate an analysis context who describes the subset of elements that are needed as well as their relationships through constraints and properties.

Step 4 -Requirement Traceability, Verification and Validation: Based on the previous steps, with the help of specific simulation and calculation tools the developed system model has to be verified and validated against the requirements. The procedure takes place in iterative loops.

Step 5 -Interpretation and Visualization of the Results:

In this step, the interpretation and visualization of the results are carried out. Concrete recommendations for decisions have to be derived from it.

Case Study: Modeling Behavior in an Exemplary System Model

The specification of the system model by structure elements in the early phase is too coarse for a detailed assessment which can support the engineering eco-design. It is important to take the usage phase into account already in the early design phase and to provide traceability between the requirements of the product (see figure 4: R-level) and the product's physical elements (see figure 4: P-level). Based on a simple and abstract example for the modification of an environmental constraint, it will be shown how it is possible and helpful to consider the requirements derived from the usage phase of a working machine, or a similar product, already in the early phases of development by using Model Based Systems Engineering.

Problem description:

The greenhouse gas emission for a working machine, e.g. in Japan, should be lowered to a maximum average value of 1.000 t CO2-eq. (based on the results of figure 1 in our example we limit the accruement of the greenhouse gas emission on only the usage phase).

Step 1 -Identification of Key Drivers Following the RFLP Approach:

At the example of changed requirement on the allowed average CO2-equivalent emissions of the machine, the traceability provided by the presented approach will help to identify the engine, for example, as a key driver at the logical system level. Figure 4 describes the context schematically. Step 2 -Specification of Behavior Artifacts in the Early Phase: Since the engine as an assembly is not of big importance for the environmental impact, rather a quantitative consideration of working behavior, energy consumption and thereof resulting emissions has to be taken as a basis. The mainly used functionalities have to be modeled at the beginning of the specification and to be considered in dependence of the design of the machine for the specific market. The Systems Modeling Language (SysML) allows describing these major functions in an abstract way with the help of the Use Case Diagram. It illustrate how the system is used to achieve the goals set by its users and with what elements it interacts during operation. These could be people, other systems or the environment [START_REF] Friedenthal | A Practial Guide to SysML -The Systems Modeling Language[END_REF]. Based on the example of the wheeled excavator (see Chapter 2), the lower right part of figure 5 shows the main use case scenarios according to the test methods for energy consumption of hydraulic excavators [START_REF] Jcmas H | Earth-Moving Machinery Test Methods for Energy Consumption of Hydraulic Excavators[END_REF] modeled in SysML. One possible way to define these use case scenarios in SysML is to associate them with activities in a block context including relevant properties as parameter elements [START_REF] Delligatti | SysML Distilled -A Brief Guide to the Systems Modeling Language, Addison-Wesley[END_REF].

Activities in SysML describe behaviors performed by specific parts of a system or their components over the entire lifecycle [START_REF] Friedenthal | A Practial Guide to SysML -The Systems Modeling Language[END_REF]. The relations between different model elements (see figure 5) in the system are described through allocation relationships. In regard to the further use of the defined parameter properties, it is important to differentiate their types in the SysML model. The parameter properties might be based on a specification (such as a limitation through a requirement) or on a prediction (such as results from simulations or conclusions from field data). In the considered situation of usage cycles of a wheeled excavator, a running time of 15.000 hours is supposed to be a specification property as well as a new limitation rate for a greenhouse gas emission lower than 1.000 t CO2-eq. A prediction property is represented in this case by the simulated value.

Step 3 -Analysis of Behavior Artifacts in the Early Phase:

To simulate or calculate the emission values of the different use cases or, respectively, the emission of the whole wheeled excavator in regard to its usage, SysML allows generating a first specification of a simulation through different diagrams. With the help of a Block Definition Diagram it is possible to determine the context of an analysis (see figure 6). Blocks of the system which are utilized in this context are linked to the analysis block by associations. These blocks provide the parameters that are used for the analysis and a placeholder for prediction properties which represent the outcoming results. The current calculation is described by different constraints. These constraints are connected to the analysis context element through a composite association. With the help of the SysML parametric diagram the relationship between the different model elements of the analysis context can be described through their parameters and specified constraints [START_REF] Delligatti | SysML Distilled -A Brief Guide to the Systems Modeling Language, Addison-Wesley[END_REF]. Figure 7 clarifies the mathematical progression for the calculation of the greenhouse gas emissions of the whole wheeled excavator, as well as separately for the different use case scenarios. Additionally the constraint block 'Compare' checks if the current value satisfies the given requirement. Based on the information of this diagram and the structural system description, test cases can be generated and executed by specific calculation and simulation tools. Step 4 -Requirement Traceability, Verification and Validation: In the current example, a need for action on the system's L-level can result from the changed requirement on the average CO2-eq. emissions and the engine has been tracked down as main driver of the impact. We now consider the machine's behavior over its lifetime (see Table 2) assuming (in reality this would be known) the following localized working-cycle distribution: Arising from a machine lifetime of 15.000 hours of operating service the following values for greenhouse gas emission as shown in Table 3 are the results of this calculation. In regard to the result and with the help of the SysML model it is possible to trace the value to concrete components, functional and logical elements and thereby realize most suitable fields of action. Furthermore new requirements based on this specific working cycles could be added.

Step 5 -Interpretation and Visualization of the Results: In the current example and based on the results the implementation of a start-stop system for reduction of the time spent in idling would bring a necessary improvement (or optimizing the drive train would be a better option) or one will have to move to the F-level and look for alternative concepts. Last but not least, this information has to be visualized in an easy to interpret way and supplied to decision-makers. An appropriate integration of the proposed behavior artifacts and of a general behavior description into the System Lifecycle Management backbone is part of further research.

Conclusion and Outlook

Modeling a complex product system requires the integration of various authoring systems and the product structure with related processes. Following this way, full traceability can be achieved. The paper introduced System Lifecycle Management as key concept integrating the introduced two layers. The proposed approach which is based on methods of Model Based Systems Engineering addresses exemplarily one specific outlined problem of a sustainable development process of a product system. The paper reuses and adapts existing modeling constructs for capturing relevant behavior artifacts at the example of the usage phase of a wheeled excavator. Semantic links are formalized between early definition phase and first prediction in the form of constraint blocks regarding sustainable product development. For the future, the implementation of the introduced approach will be provided within a System Lifecycle Management backbone. To give the user the capabilities to easily trace the impact of design decisions, an intuitive and graphically rich user interface will be implemented on top of the System Lifecycle Management backbone.

Fig. 1 .

 1 Fig. 1. Environmental Impact (Example: Greenhouse Gas Emission)Regarding the Lifecycle of a Commercial Vehicle (adapted from[START_REF] Eigner | Improving the Life Cycle Eco Performance of a Wheeled Excavator -in the context of ERMA[END_REF]).

Fig. 2 .

 2 Fig.2. Two-Layer-Model of System Lifecycle Management (adapted from[START_REF] Eigner | Modellbasierte Virtuelle Produktentwicklung auf einer Plattform für System Lifecycle Management[END_REF] and[START_REF] Paredis | Why Model-Based Systems Engineering? -Benefits and Payoffs[END_REF]).

Fig. 3 .

 3 Fig. 3. Extended V-Model for Multi-Disciplinary Product Development (based on VDI 2206 [8], adapted from [24][25]).

Fig. 4 .

 4 Fig. 4. Schematic Representation of the Identification of Key Drivers through theTraceability along RFLP (adapted from[START_REF] Eigner | Proposal for Functional Product Description as Part of PLM Solution in Interdisciplinary Product Development[END_REF]).

Fig. 5 .

 5 Fig. 5. Setting of Use Cases and their Parameters Referring to Logical Solution Elements.

Fig. 6 .

 6 Fig. 6. Definition of an Analysis Context for the Greenhouse Gas Emission of a Wheeled Excavator.

Fig. 7 .

 7 Fig. 7. Parameter Relations for the Analysis of Greenhouse Gas Emission.

Table 1 .

 1 Key Drivers of Environmental Impact.

	Lifecycle Phase	Environmental Impact Parameter
	Production	Raw material extraction
		Manufacturing processes
	Operation	Usage, Maintenance, Energy consumption
		Replacement of spare parts and fluids
	Recycling	Recycling, Disposal,
		Includes all waste from maintenance

Table 2 .

 2 Exemplary Working Cycle Distribution of an Excavator (according to[START_REF] Jcmas H | Earth-Moving Machinery Test Methods for Energy Consumption of Hydraulic Excavators[END_REF]).

	Working Cycle	Grading	Trenching	Lifting	Traveling	Idling
	Percent of life time	25%	25%	10%	17%	23%
	Fuel consumption, kg/h	34	30	26	31	8

Table 3 .

 3 Results from the Calculation in Different Working Cycles

	Working Cycle	Grading	Trenching	Lifting	Traveling	Idling
	CO2-eq. Emission	340,4 t	300,4 t	104,1 t	211,2 t	73,7 t
	Total			1029,3 t

Table 3 .

 3 Variation referring to the Calculation in Different Working Cycles

	Working Cycle	Grading	Trenching	Lifting	Traveling	Idling
	Life time in hours	3.750	3.750	1.500	2.550	1.050
	CO2-eq. Emission	340,4 t	300,4 t	104,1 t	211,2 t	22,4 t
	Total			978,5 t

Team Data Management (TDM): Authoring tool-close (local) management system for a development team, regardless of the PLM backbone.

Requirement, Function, Logical System Element, Physical Part, etc. (R, F, L, P, …): Defines information artifacts out of system or product model within the development process.

Acknowledgments. The authors would like to acknowledge funding from the German Bundesministerium für Bildung und Forschung attended by PTKA for research of mecPro 2 and from Stiftung Rheinland-Pfalz für Innovation for research of ERMA. The authors would like to thank Torsten Gilz and Radoslav Zafirov for their contribution and research on the topic of Model Based Systems Engineering, for their input and assistance.