Irene Roda
email: irene.roda@polimi.it

Marco Garetti
email: marco.garetti@polimi.it

TCO Evaluation in Physical Asset Management: Benefits and Limitations for Industrial Adoption

Keywords:

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

Introduction

In the industrial sector, the operating time of the production asset after the green-field investment is typically long and during such time numerous rebuilds, replacements and expansion investments take place. All of these decisions, together with the chosen operations and maintenance strategies, affect the productivity of the physical capital [START_REF] Komonen | An asset management framework to improve longer term returns on investments in the capital intensive industries[END_REF][START_REF] Tam | A generic asset management framework for optimizing maintenance investment decision[END_REF]. In order to meet the challenge of low returns on investment and realize value from asset, enterprises need to adopt an asset management strategy and system (ISO 55000:2014(E), 2014). Within it, one of the challenges for supporting decision-making along the asset lifecycle, is to improve the quantification process of costs so to be able to evaluate the total cost of a production system throughout its life cycle (i.e. the Total Cost of Ownership (TCO)) (IAM, 2012; [START_REF] Parra | Non-homogeneous Poisson Process (NHPP), stochastic model applied to evaluate the economic impact of the failure in the Life Cycle Cost Analysis (LCCA)[END_REF].

Methodology

This paper aims at defining a framework that categorizes the benefits and potential applications that a TCO model can have in asset management for different stakeholders. In order to do so, an extensive literature review has been developed as a keyword search, both through library services (Scopus, Google Scholar etc.) and a wider surfing in the web to consider journals and conferences publications, but also white papers and industrial reports. The analytic categories that allowed the classification of the reviewed literature and the definition of the framework have been derived both deductively considering the body of theory in the physical asset management and inductively from the material analyzed by means of generalization (Mayring, 2003).

Once defined the framework, empirical evidences have been analyzed so to confirm it from a practical point of view. This also allowed identifying the main limitations for the adoption of TCO models, trough the development of a multiple case study. Details on the related methodology are given in Section 4.

TCO applications and benefits: definition of a framework

It is widely accepted in the academic literature [START_REF] Schuman | Asset life cycle management: towards improving physical asset performance in the process industry[END_REF]) that TCO should be an integral part of an asset management strategy and the same is assessed by the body of standards ISO 55000 on asset management (ISO 55000:2014(E), 2014). In the latter, it is indicated that: "[…] Life cycle cost, which may include capital expenditure, financing and operational costs, should be considered in the decisionmaking process". Moreover, companies are acknowledging how TCO can represent a reliable economic-sound support for taking decisions and to convey the information to people in different parts / functions of the same organization, or outside the company, such us costumers / suppliers. The ability to effectively identify cost drivers and manage cost reductions is a competitive advantage for companies [START_REF] Heilala | Total cost of ownership analysis for modular final assembly systems[END_REF].

The framework

Based on the literature review, a framework has been developed identifying the benefits for a company of having a TCO evaluation model supporting the decision-making process. The framework is organized on three main dimensions: i) type of stakeholder, ii) type of supported decision, iii) phase of the life cycle.

 Type of stakeholder. Different stakeholders with different perspectives can be interested in TCO analysis. Given the meaning itself of TCO, it is evident that asset users (industrial equipment or plant owners / managers) are the primary interested subjects. Nevertheless TCO is also a relevant issue for asset providers (industrial equipment or plant builders / manufacturers) [START_REF] Barringer | A life cycle cost summary[END_REF]. Clearly it has to be considered that each of the two types of stakeholders has some common and some distinguishing reasons for interest on TCO. Besides, it must be considered that the ability of a provider to perform TCO evaluation is affected by the quality of information available in a higher way than the users' one [START_REF] Korpi | Life cycle costing: a review of published case studies[END_REF].  Type of supported decision. A TCO model has potentiality to support different kinds of decisions. In particular, two main categories have been identified: (i) configuration decisions and (ii) management decisions. The first category includes all those decisions that have direct influence on the asset configuration, while the second one refers to those decisions that deal with the management, operation and maintenance of the asset.  Phase of life cycle. TCO analysis is preferably carried out in any and all phases of an asset's life cycle to provide input to decision makers [START_REF] Kawauchi | Life Cycle Cost (LCC) analysis in oil and chemical process industries[END_REF][START_REF] Schuman | Asset life cycle management: towards improving physical asset performance in the process industry[END_REF]. According to the conventional perspective, the lifecycle of an asset is composed by three main phases: beginning of life (BoL) including the activities for bringing an asset into operation (conceptualization, design, construction, installation and acquisition), middle of life (MoL) including the activities involved in asset operation and maintenance and finally the end of life (EoL) involving the final retirement of the asset (Amadi-Echendu, 2004).

The developed framework (Table 1) shows which benefits a TCO model can bring to each of the two types of stakeholder at each lifecycle phase by supporting different kinds of decisions (configuration or management decisions). In the following subsections the content of the framework is articulated considering each lifecycle phase. BoL-According to several authors; cost must be an active rather than a resultant factor throughout the system design process (Fabrycky and Blanchard, 1991; Waghmode and Sahasrabudhe, 2012; [START_REF] Woodward | Life cycle costing-theory, information acquisition and application[END_REF]. Though, generally speaking only 15% of the total TCO is consumed during the design phase, research has shown that as much as 85% of the remaining TCO is determined by decisions made during this stage [START_REF] Lad | Integrated reliability and optimal maintenance schedule design: a Life Cycle Cost based approach[END_REF]. TCO evaluation at this step allows providers and users to economically evaluate different scenarios at a pre-design step [START_REF] Carpentieri | A life cycle cost framework for automotive production lines[END_REF]; determining the most cost efficient design amongst a set of alternatives; identifying cost drivers for design changes and optimization and, determining the cost of a design for budgetary purposes [START_REF] Korpi | Life cycle costing: a review of published case studies[END_REF]. TCO can be seen also as a procurement (from the user perspective) and sales and marketing (from the provider perspective) tool. [START_REF] Snelgrove | Value pricing when you understand your customers: Total cost of ownership-Past, present and future[END_REF]) asserts that at the heart of pricing and selling in the twenty-first century is the ability to price based on created value. Moreover, TCO allows abandoning traditional feature-based marketing showing how the offered asset creates specific benefits considering its lifecycle and its effect on customer profitability. On the other side, through TCO, users are able to support their suppliers selection and evaluation steps [START_REF] Ellram | Total cost of ownership: a key concept in strategic cost management decisions[END_REF]). In the BoL phase the supplier can also be interested in TCO evaluation in case there is the possibility to enter into a service contract. TCO model is also able to support investment decisions supporting budget planning and costs control helping preventing decision makers from incurring investments which might be cheaper in acquisition, but significantly more expensive in O&M and consequently in total costs over their life cycle. Finally TCO plays a supporting role during the construction & installation phase for asset providers. In fact, although it is a late stage in the project for major changes, recommendations should still be considered in terms of TCO and the most favorable solution implemented. Spare parts requirement and provision can be evaluated at this phase [START_REF] Schuman | Asset life cycle management: towards improving physical asset performance in the process industry[END_REF].

MoL-The evaluation of TCO and its usage for decision making support does represent a relevant aspect also during the MoL phase of an asset, both for configuration and management decisions, mostly for the asset users. At this stage, the asset is operative and, compared to the design stage, the level of uncertainty for the TCO evaluation is lower [START_REF] Kawauchi | Life Cycle Cost (LCC) analysis in oil and chemical process industries[END_REF]. Opportunities for reduced support costs and more effective support are based on the systematic capture and reuse of all information throughout the equipment life cycle; hence the best scenario is the case where data for technical performance evaluation are regularly collected. If this is not possible, the uncertainty in cost evaluation is anyways lower given that even if the analysis are based on estimations by people working on the field, these are related to an existing and operative asset. The use of TCO in this step can support asset users for configuration decisions such as the evaluation of the reconfiguration of the asset by applying some changes in the current layout for achieving a better availability level, involving also considerations on the WIP level [START_REF] Tomasella | Through-life management of engineering assets[END_REF]. Moreover TCO evaluation can support management decisions such as the evaluation of changes in the actual maintenance strategy [START_REF] Lad | Integrated reliability and optimal maintenance schedule design: a Life Cycle Cost based approach[END_REF][START_REF] Woodward | Life cycle costing-theory, information acquisition and application[END_REF]. Likewise, decisions on the operative conditions of the asset; its utilization and the production strategies can be supported by the TCO evaluation.

EoL-TCO has got relevance also at the End of Life of an asset. In fact, in this stage the asset is taken out of service for disposal or redeployment. In the latter case a potential new TCO may begin [START_REF] Woodward | Life cycle costing-theory, information acquisition and application[END_REF], therefore the asset manager may use the TCO evaluation of the existing asset in order to support decisions for rehabilitation or reuse of the asset itself [START_REF] Asiedu | Product life cycle cost analysis: State of the art review[END_REF][START_REF] Shahata | Simulation as a tool for life cycle cost analysis[END_REF]. What emerged is that TCO is useful in asset provider -asset user communication, and helps in trade-off analyses of system concepts [START_REF] Heilala | Total cost of ownership analysis for modular final assembly systems[END_REF]. The core aim of a TCO evaluation is to avoid problem shifting decisions by keeping an integrating perspective.

The industry-influence

An additional aspect that emerged from the literature analysis is about the influence of the type of industry a company belongs to, on the value given to TCO analysis. The TCO concept was firstly introduced for procurement purposes by the US Department of Defense in 1960 and its importance in defense was stimulated by findings that operation and support costs for typical weapon systems accounted for as much as 75% of the total cost (Asiedu and Gu, 1998). Since then the need for more extensive application of engineering economy methodologies in the planning and control of production systems has been more and more recognized. The applications of LCC analysis have then spread to other industries such as oil and chemical industries [START_REF] Kawauchi | Life Cycle Cost (LCC) analysis in oil and chemical process industries[END_REF]. Not surprisingly, the concept originally spread among the process industry and more in general in capital-intensive industries where physical asset management represents a strategic resource given the high vulnerability to disturbances and the need for production / operation regularity that characterize them. Currently, the interest for TCO is rising in the discrete manufacturing industry too. In fact, the emergent global competition is forcing companies to estimate and optimize the overall system life cycle cost with reference to performance, safety, reliability and maintainability (Waghmode and Sahasrabudhe, 2012) to be able to compete not only on price, but also on cost effectiveness and technological leadership [START_REF] Lad | Integrated reliability and optimal maintenance schedule design: a Life Cycle Cost based approach[END_REF]. More and more contracts are based on TCO evaluation in several sectors such as the automotive, the packaging and the food sectors. Table 2 presents the concept emerged highlighting the critical factors connected to the TCO relevance for capital-intensive and discrete manufacturing industries.

Practical implications: empirical evidences

In order to corroborate the developed framework from an empirical point of view a case study was developed. The aim is to understand if the benefits that have been identified in literature are recognized in practice and which are the limitations for the adoption of TCO. Two companies belonging to different industries were selected. Company A is a small medium company in the discrete manufacturing industry while company B is a big company belonging to the process industry. They have different perspectives on asset management since company A is asset provider while company B is asset user. These differences have been selected referring to the different dimensions of the framework, and to the industry dependency highlighted in section 3. The case has been based on semi-structured interviews and on a defined questionnaire.

A first aspect that emerged from the case study is the different involvement and interest in using the TCO in different life cycle phases depending on the kind of stakeholder the two companies represent. Indeed, Company A (provider) declared to be directly involved and being able to take decisions mostly in the BoL phase. In fact, the company is responsible of the design and installation of the asset it produces and its role in the MoL phase is limited to providing the clients with manuals and guidelines for the maintenance activities. No service is provided in this case by A to its clients. On the other side, Company B is an asset user and it is directly interested in the management of its assets in the MoL phase and in the evaluation of investments for new installations. It has to be specified that Company A recently started to look at TCO as a potential tool and is now pushing its importance at strategic level; instead for Company B the TCO concept is consolidated even if it is still looking for a tool able to integrate technical evaluation into cost estimations. The following table refers to the proposed framework and shows which are the decisions that TCO evaluation can support according to the judgments of the two companies; based on the relevance for the business. The results from the two cases endorse what was expected by the literature and confirm the benefits defined in the framework. The case study was also useful to identify the main limitations in the adoption of TCO in practice. In particular, the main findings that emerged are the following:  both companies assessed the need for a TCO tool able not only to consider all the relevant cost items along the asset lifecycle, but also the technical aspects that have influence on it (the authors developed a literature review about this issue in (Roda and Garetti, 2014));.  there is the need for a reliable database with both economic and technical parameters to be used for the TCO evaluation; in particular, the main problem for Company A is the necessity for a strict collaboration with its customers in order to get da-ta for the evaluation of the OPEX of the asset under analysis; while Company B needs to focus on a system able to record relevant data regarding the behavior of its asset (failures events, set-up times etc.);  the use of the TCO at the disposal phase is not considered as a relevant issue for both companies at the moment;  general desires to minimize the initial expenditures in order to increase return on investment, and general lack inside the organizations of the adequate consideration of the asset life cycle that requires inter-functional cooperation and alignment;  in general, TCO is seen as a powerful communication tool by both kind of stakeholders, being able to inform different kind of actors, the customers but also the top management by supplying the value of the asset through the language of money, eventually incorporating technical considerations.

Conclusions and future research

The paper presents a framework that describes the main applications and benefits that the evaluation of the TCO of industrial asset has got both for asset users and asset providers along the asset life cycle. Moreover, a case study analysis was implemented for an empirical assessment. The investigation confirmed that TCO represents a useful indication for guiding asset managers in the decision making process for harmonizing the never ending conflicts by focusing on facts, money, and time [START_REF] Barringer | A life cycle cost summary[END_REF] and, if properly estimated it does represent a competitive advantage for companies. It was possible to identify benefits of TCO for decision-making support at each life cycle phase of an asset and it emerged that its application can have positive effect on cost control, management of the asset, investments evaluation, sales and marketing strategy support, etc. Nevertheless, up to day, there are still a number of difficulties that limit a TCO model widespread adoption by industry. This problem emerged from the case study and it is a fact that there is no single calculation model that has been accepted in practice as a standard so far. The research plan of the authors of this paper is to develop a generalizable TCO evaluation methodology based on a critical analysis of some of the existing proposed solutions that go in this direction too. Future research should try to overcome the adoption limitations by identifying which are the existing barriers and defining a methodology for evaluating TCO that can be used as a real support in decision making. A step of the research may include widening to other companies the industrial assessment through the case study development to better identify the practical adoption's criticalities.

Table 1 .

 1 Framework

		ASSET PROVIDER	ASSET USER
		Configuration	Management	Configuration	Management
		-Evaluation of project alterna-	-Communicating value to	-Evaluation of design	-Suppliers and tenders
		tives	the customer and selling	alternatives offered by a	evaluation & selection
	BOL	-Comparison and optimization of design alternatives -Components / equipment	support -Propose to the clients specific design solutions	provider [6]	-Maintenance service contract evaluation -Investment, budget
		procurement and construction	-Pricing		planning, cost control
		alternatives evaluation	-Contracting maintenance		[13], [5],[17], [22]
		-spare parts requirements esti-	services provision
		mation. [4], [13], [2], [17]	[4], [13], [17] , [19]
		-Proposal of re-configuration	-Maintenance service	-Reconfiguration decisions	-Maintenance scheduling
	MOL	solutions	provision offering -Spare parts provision offering	-WIP sizing [21]	and management -Repair level analysis -Asset utilization and
					production strategies
					[3],[14],[13]
	EOL	-Proposal of reconfiguration for EoL optimization	-Evaluation and proposal of rehabilitation strategies	-Reuse strategies for components / machines	-Evaluation of rehabilita-tion strategies [2], [18], [22]

Table 2 .

 2 Relevance and critical factors of TCO in process and manufacturing industries

	Type of industry	Critical factors	TCO relevance
	Process industry	 capital-intensive assets	 High strategic relevance of TCO for
	(power, mining and oil,	 high vulnerability to disturbances need	supporting decision making in physi-
	chemical sectors…)	for production regularity	cal asset management
	Discrete	 high competition and need to compete	 TCO is getting more and more rele-
	manufacturing	on cost effectiveness and technological	vance to demonstrate value for money
	industry (packaging…)	leadership than just on price	of investments.

Table 3 .

 3 The TCO benefits: results from the case study

		COMPANY A (ASSET PROVIDER)	COMPANY B (ASSET USER)
		Configuration	Management	Configuration	Management
		-Comparison and optimiza-	-Communicating value to	-Evaluation of design	-Suppliers and tenders evalua-
	BoL	tion of design alternatives	the customer and selling support	alternatives	tion & selection -Maintenance service contract
			-Propose the clients specific		evaluation
			design solutions		-Investment, budget planning,
					cost control
		-System reconfiguration	-Possibility to develop	-Reconfiguration deci-	-Maintenance scheduling and
	MOL	proposals	service offering	sions	management -Repair level analysis


Natalia Svensson Harari
email: natalia.svensson.harari@volvo.com

Christer Osterman
email: christer.osterman@scania.com

Jessica Bruch
email: jessica.bruch@mdh.se

Mats Jackson
email: mats.jackson@mdh.se

Flexibility in Lean Mixed Model Assembly Lines

Keywords: Mixed model assembly lines, lean, flexibility

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

Introduction

Due to changing demands and shorten product life cycles, manufacturing companies deal with strategies to handle a variety of products and production volumes in their assembly systems. Assembly systems in the automotive industry in Sweden today are usually semi-automated mixed model lines where different product variants are assembled and operators are in charge of performing most of the assembly processes.

Influenced by lean strategies, approaches to level production volumes and rationalization through elimination of the so called non-value-adding work are used. Different dimensions of flexibility have been described in the literature and difficulties of generalizing flexibility measures may be encountered [START_REF] Koste | A Theoretical Framework for Analyzing the Dimensions of Manufacturing Flexibility[END_REF]. Manufacturing settings are usually used when defining flexibility characteristics, and more information about them in assembly systems is needed beyond the efforts on describing Flexible Assembly Systems. These have been most of the times referred to as automated systems.

The purpose of the research presented in this paper has been to characterize flexibility in lean mixed-model assembly lines (MMAL) through exploring mechanisms used to achieve flexibility taking into account the constituents of the assembly system described in the literature: human system, technical system, material handling system, information system and building and premises [START_REF] Rösiö | Supporting the Design of Reconfigurable Production Systems[END_REF].

Frame of References

Flexibility Dimensions and Measures

There are differences in meanings regarding flexibility as well as variation in perspectives specially when broken down into its dimensions, elements, and measures [START_REF] Souza | Toward a Taxonomy of Manufacturing Flexibility Dimensions[END_REF]. To characterize flexibility, [START_REF] Upton | The Management of Manufacturing Flexibility[END_REF], presented a framework of flexibility management regarding dimensions, time horizon and elements. Dimensions concern the required flexibility and need to change. Time horizon is related to the timeframe in which the change will occur. Elements of flexibility concern range, uniformity or mobility [START_REF] Upton | The Management of Manufacturing Flexibility[END_REF]. Dimensions of flexibility have been described by different authors such as [START_REF] Browne | Classification of Flexible Manufacturing Systems[END_REF], [START_REF] Sethi | Flexibility in Manufacturing: A Survey[END_REF], and Gupta and Somers (1992) [START_REF] Browne | Classification of Flexible Manufacturing Systems[END_REF][START_REF] Sethi | Flexibility in Manufacturing: A Survey[END_REF][START_REF] Gupta | The Measurement of Manufacturing Flexibility[END_REF]. [START_REF] Koste | A Theoretical Framework for Analyzing the Dimensions of Manufacturing Flexibility[END_REF], proposed a theoretical framework to analyze flexibility dimensions where 10 dimensions of flexibility were considered; Machine flexibility (number and variety of operations the machine can perform), Labor flexibility (number and variety of operations/task that workers can perform), Material handling (number of paths and variety of material), Routing flexibility (number of products with alternate routes and extend of variation between routes), Operation flexibility (number of products with alternate sequencing plans and variety of plans), Expansion flexibility (number and variety of expansions), Volume flexibility (extend of change and degree of fluctuations in output level), Mix flexibility (number and variety of products that can be produced), New product flexibility (number and variety of products that can be introduced), Modification flexibility (number and variety of product modifications), all of them without incurring in high transition penalties or large changes in performance outcomes [START_REF] Koste | A Theoretical Framework for Analyzing the Dimensions of Manufacturing Flexibility[END_REF]. The elements of flexibility have been then defined by them as; Range-Number (number of tasks, products, etc), Rangeheterogeneity (differences in task, products, etc.), Mobility (transition penalties -time, cost, effort) and Uniformity (similarity of performance outcomes such as quality, cost, time) [START_REF] Koste | A Theoretical Framework for Analyzing the Dimensions of Manufacturing Flexibility[END_REF]. Based on Atkinson, (1984) and Allvin and Aronsson, (2013) some definitions of labor flexibility are further described; Functional flexibility (capacity of the job and the organization of work such as teamwork. It implies a reorganization and conversion of the operators to new work tasks. These methods are used for practical and immediate purposes), Numerical flexibility (adaption of the workforce to the changes in production not related to the performance of work. Some examples of this are: temporary employment, outsourced personnel and staffing agencies.), Temporal and financial flexibility (adjusting working time or labor cost. It could also include variable salaries.) [START_REF] Atkinson | Manpower Strategies for Flexible Organizations[END_REF][START_REF] Allvin | Flexibility, Boundarylessness and the Strategies of Work[END_REF].

Lean Mixed-Model Assembly Lines

The necessity of using the same equipment and line for different models was one of the driving forces behind the development of the Lean methods and principles [START_REF] Ohno | Toyota Production System, Beyond Large-Scale Production[END_REF]. In a Lean assembly line the Takt time is used to organize and balance the line. When producing a mix of models, some degree of leveling is necessary [START_REF] Wilson | How to Implement Lean Manufacturing[END_REF]. Even when the cycle-time of each particular model could be different, the overall takt time remains the same. This can be accomplished with internal buffers acting as de-couplers in the process but preferable with set up time reduction [START_REF] Shingo | A Revolution in Manufacturing: The SMED System[END_REF]. Just-In-Time (JIT) is a concept where the parts used in assembly are paced using a Kanban system to create pull in production and avoid waste [START_REF] Ohno | Just-In-Time, For Today and Tomorrow[END_REF] where the upstream process only produces as much as the downstream process consumes. The pull principle requires consistent leveling to reduce variation in demand. A Kanban system has several aspects and can be used to regulate the material flows as well as the assembly orders [START_REF] Dennis | Lean Production Simplified[END_REF]. Standardized work connects resource efficiency with flow efficiency through the balancing of the process. Standardized work is connected to standard time [START_REF] Baudin | Lean Assembly[END_REF] thus reducing variation in the assembly process. To handle different work content that products could have, solutions such as variation of workers in assembly, utilizing sub assembly lines, and concentrating imbalances to particular points of the assembly process are used [START_REF] Baudin | Lean Assembly[END_REF]. Regarding setup times, different products require different fixtures. Changing can take time, reducing the flow efficiency of the process. Commonality of interfaces, generalized tools and fixtures and various SMED principles are used [START_REF] Shingo | A Revolution in Manufacturing: The SMED System[END_REF]. Planning and mixing rules are used to handle variation of customer demands. Problem solving and continuous improvement activities are carried out.

Methods and Techniques

The research method was based on a multiple-case study design as described by Yin (2014) [START_REF] Yin | Case Study Research: Design and Methods[END_REF]. It was a quali-quantitative and participative study. The literature review gave input to the design of the research study. The study focused on flexibility of volume, mix, operation and flexibility to introduce new products and remove existing ones. The assembly system was analyzed from all its constituents: human system, technical system, material handling system, information system and building and premises [START_REF] Rösiö | Supporting the Design of Reconfigurable Production Systems[END_REF]. The study was conducted in two Swedish manufacturing companies, defined as Case A and Case B producing the same component in MMALs with production systems based on lean principles. The study was conducted by two researchers from June 2013 until April 2014. The design of the data collection protocol consisted of: Informed consent, background information of the participant, recorded semi-structured interviews, observations protocol. A pilot study was developed at the same companies but in different assembly areas. Active observations were made at the lines. In total 11 semi-structured interviews of around 1 hour were conducted to production managers, production technicians and logistics managers. The interviews were developed by function, conducted in Swedish, recorded and transcribed for reliability. The analysis of the data used the approach of Miles and Huberman, (1994) [START_REF] Miles | Qualitative Data Analysis: An Expanded Sourcebook[END_REF]. The collected data and transcriptions went through data reduction process and analysis supported by the frame of references. The results of each case were then used to draw cross-case conclusions.

Empirical Findings

The study concerned the assembly of a specific component referred as component X, Y and Z. Three assembly lines were studied in Case A which assembled X, Y and Z according to the final products. Case B had different assembly lines for X, Y and Z for different final products. Two assembly lines were studied in Case B. Both companies worked with modularization in their products, and mutual processes, tools, infrastructure, resources between models were used. Case B had a modular system established at the company. Both worked with semiautomatic hand-tools connected to andon systems and also customized fixtures and tools. Teams of 5 or 7 operators and 1 team leader worked along the lines. One or two operators worked in parallel by station depending on the product variant. Operators were employed by the company or outsourced in permanent and temporal terms. Stairs salary systems related to the competence were used. The takt time of the cases had differences. Case A used stop and go AGV´s systems. Operators rotated according to a schedule. Training and education of new operators was done in the line by the team leader. The company used a centralized material handling area. Some parts were delivered using poka-yoke solutions. Around 6 to 14 variants were assembled. The number of operators per line varied from 7 to 15, and the main lines had 3 or 4 stations. Case B used a continuous moving overhead conveyor as well as robots at some stages and elevators to transport the parts. Operators rotated every half an hour. Training and education of new operators was done in a separate area. Different material handling areas were dedicated for each line. Kits and moving racks beside the line were used. More than 100 variants were assembled. The number of operators per line varied from 70 to 105 and the main lines had 20 to 30 stations plus internal buffers and one area for special products.

Mechanisms to achieve flexibility

Volume Flexibility. Related to the capacity of the system, the cases analyzed scenarios of volume change followed by a decision making process. The balance of the line was a determining factor in the decisions. According to the magnitude of the volume change, they usually started with changes in shift-forms and working times, increasing or decreasing the number of employees avoiding possible changes in the current takt time and rebalancing the line, until the point when the capacity was exceeded and investments were needed. Logistics needed to adapt its capacity according to assembly. When assembly volumes decreased, they tried to maintain the same takt time using strategies such as takt holes. One consequence of decreasing personnel was that competence needed was lost also for scenarios when volume increases again. Case B had agreements with the Union concerning flexible working times and time banks for periods of increase or decrease of the based takt time. Mechanisms used to achieve volume flexibility are shown in Figure 1. Mix and Operation Flexibility. Both companies delivered a variety of products.

Assembly shared resources and processes for a variety of products. Alternate areas were used for products with high differences in work content in Case B. About operation flexibility, an assembly plan containing the variety of models was delivered in the first positions at the line specifying the sequence of models to be assembled. Some distinctions should be made in relation to the definition of sequence in assembly.

Sequence could be referred as the sequence of processes in which the products are assembled, but sequence is also referred to as the order in which the different models will be assembled during the shift connected to customer orders and balance in the line. Mechanisms used to achieve product mix and operation flexibility are shown in New Product and Removal of Existing Product Flexibility. The introduction of new products was considered a complex project in both companies. Challenges were related to cooperation between product design and assembly upon the technical implications from both perspectives and e.g. due to ergonomics. The companies analyzed the design of new products in relation to the existing ones to make possible the use of e.g. existing technology and resources. However, evaluations of possible modifications that did not destabilize the current assembly were also made as well as due to a potential need of building new assembly areas. Involvement of different levels of the organization was mentioned to be needed, due to possible new methods, instructions, times, technology, etc. Removal of existing products required the participation of preparation areas in coordination with assembly and logistics. Mechanisms used to achieve new product and removal of existing ones are shown in Figure 3.

Fig. 3. Mechanisms used to achieve new product/removal of existing products flexibility and its relation with the assembly system constituents.

Analysis

The cases illustrate mechanism used to achieve flexibility and its relation with the assembly system constituents. To achieve volume, mix and operation flexibility and new product/removal of existing products flexibility, other flexibilities have been used. An overview of these results is shown in Figure 4. According to the results, the timeframe in which those mechanisms were used varied. Different kinds of labor flexibility such as functional, numerical and temporal took place in shorter periods of time compared to expansion flexibility or flexibility to introduce to new products due to e.g. investments. Already mentioned in the literature, introduction of new product flexibility could be related to flexibility to introduce new technology [START_REF] Ohlager | Produktionsstrategier, TPPE50, Institutionen för Produktionsekonomi[END_REF]. Routing flexibility is not really used in MMAL; instead the assembly sequence is taken into account. When differences are considerable between products, they are clustered or other assembly areas are used. The results suggest that the flexibility of a MMAL is related to its design and the options it has to be flexible are until some extent circumscribed by it.

Even though one of the cases had a modular system established at the company, common mechanisms to achieve flexibility were found between the cases. However, differences exist e.g. in the number of models assembled. This suggest that modularity could until some extend facilitate the introduction of new products, but other capabilities are still needed such as cooperation between assembly and product design, appropriate technical evaluations, involvement of different levels of the organization, and infrastructure to test the new designs.

Regarding flexibility elements described in the frame of reference by Koste and Malhotra (1999) [START_REF] Koste | A Theoretical Framework for Analyzing the Dimensions of Manufacturing Flexibility[END_REF] and its relation to MMAL, it was identified that concerning rangenumber and range-heterogeneity various product models were assembled which until some extend shared assembly processes, tasks, information, parts and equipment. The products can be customized, meaning that still differences between models could exist. Regarding mobility, methods are used to reduce setup times, and there could be short tool change over times between models, some of them adjusted automatically by scanning product barcodes. About uniformity, the models are expected to follow mutual and standardize assembly processes through all the stations. The models are delivered following the same takt time. To balance the line, work content measured in time is divided in similar proportions between stations for the variety of models. The products passed through quality control checks, sometimes one station at the end of the line was also dedicated to this purpose. Information systems are used to control and secure uniformity in quality and time.

Conclusion

Flexibility is a complex definition and different perspectives exist. A characterization of lean MMALs has been presented through analysing mechanisms to achieve flexibility in two cases and their relations to the constituent parts of the assembly system.

Even though this study identified mechanisms of flexibility in assembly system related to volume, mix and operative flexibility and new product/removal of products flexibility, it has been shown that to achieve those kinds of flexibilities other dimensions of flexibility are also used. The timeframe by which these mechanisms are used vary. Regarding the elements of flexibility, lean MMALs are focused on delivering a wide range number and heterogeneity of products models by using common resources and processes. Different methods are used in regard of mobility, in order to reduce setup times and change overs. Uniformity is achieved by e.g. takt times, quality controls and standardization. By characterizing flexibility in MMALs taking into account the constituents of the assembly system, it could possible to better understand and evaluate its implications as well as its relation to the assembly system design from a holistic perspective.

Fig. 1 .

 1 Fig. 1. Mechanisms used to achieve volume flexibility and its relation with the assembly system constituents.

Figure 2 .

 2 Figure 2.

Fig. 2 .

 2 Fig.2. Mechanisms used to achieve operation and product mix flexibility and its relation with the assembly system constituents.

Fig. 4 .

 4 Fig. 4. Overview of identified flexibilities

Acknowledgment. The authors gratefully acknowledge the contributions from all the participants in the case study companies. This research work has been funded by the Knowledge Foundation within the framework of the INNOFACTURE Research School and the participating companies, and Mälardalen University. The research work is also a part of the initiative for Excellence in Production Research (XPRES) which is a joint project between Mälardalen University, the Royal Institute of Technology, and Swerea. XPRES is one of two governmentally funded Swedish strategic initiatives for research excellence in Production Engineering.


Lise Lillebrygfjeld Halse
email: lise.l.halse@himolde.no

Kristina Kjersem
email: krisina.kjersem@himolde.no

Jan Emblemsvåg
email: jan.emblemsvag@vard.com

Implementation of Lean Project Planning: A Knowledge Transfer Perspective

Keywords: Project Planning, Knowledge transfer, Implementation, Lean shipbuilding

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

Introduction

The Norwegian shipbuilding industry delivers complex and customized vessels for offshore purposes using an Engineer-To-Order (ETO) approach [START_REF] Haartveit | Integration Alternatives for Ship Designers and Shipyards[END_REF]. In this kind of production, customers' needs initiate the process of design, engineering and production [START_REF] Hicks | A Typology of UK Engineer-to-Order Companies[END_REF]. Historically, this industry is renowned for highly skilled craftsmanship that makes independent adaptations and improvements in the production process, involving exchange of tacit knowledge [START_REF] Asheim | Regional Innovation Systems: The Integration of Local 'Sticky' and Global 'Ubiquitous' Knowledge[END_REF]. In shipbuilding, project is the norm, and there is a problem with poorly planned and executed project [START_REF] Emblemsvåg | Lean Project Planning in Shipbuilding[END_REF]. The reason is claimed to be shortcomings of planning tools that were used earlier.

Consequently, Lean Project Planning (LPP) has been proposed as a new approach in this shipbuilding industry [START_REF] Emblemsvåg | Lean Project Planning in Shipbuilding[END_REF]. LPP represents a synthesis of Lean thinking ideas, Earned Value Management approach (EVM) and Last Planner System (LPP). In principle, however, Lean philosophy may not seem to be fully appropriate for ETO producers [START_REF] Cooney | Is "lean" a universal production system? Batch production in the automotive industry[END_REF], and in particular manufacturing of low-volume products such as customized ships, which is the focus of this study. Moreover, in a production environment characterized by informal planning and tacit knowledge exchange, the implementation of a formalized planning system may be further complicated, as this necessitates the conversion from tacit to explicit knowledge through formalized procedures and statements. Previous research has rarely addressed this issue. We claim that in order to understand the barriers in the implementation of formalized planning systems, we need to view the process as knowledge transfer, where the context of the recipient organization will influence to what extent and in which way the knowledge is absorbed. In this study, the implementation of Lean Project Planning (LPP) in two shipyards is studied, representing two different organizational contexts.

The rest of the paper is organized as follows: First, we present theory related to implementation of management ideas from a knowledge perspective concluding with the need to do studies where the implementation context is addressed. Thereafter, the management idea in this study, LPP, is described. We briefly address the methodology used in this study, and present the research context and the findings, which is separated in two parts: status before implementation of LPP and the implementation into the two research contexts. Finally, we present the discussion, conclusions and contribution of this paper.

2

Literature review

Implementation of Lean into the manufacturing industry has been considered as a spread of a management idea, which is translated into different organizational contexts [START_REF] Morris | Translating Management Ideas[END_REF]. However, such ideas also represent packages of knowledge that aim at improving organizations' performance and competitiveness. This suggests analyzing the implementation of management ideas as transfer and acquisition of knowledge, which is the approach in this paper.

Implementation as knowledge transfer

Generally, implementation of management practices, ideas and tools represents knowledge transfer between organizational units, where translators of the practices and ideas shape knowledge constructs in this process [START_REF] Sahlin-Andersson | Introduction[END_REF]. Several factors may affect how readily knowledge will transfer between organizational units. The nature or form of knowledge is an important aspect, and it has been claimed that explicit knowledge that is embedded in technology is more easily transferred than tacit knowledge not embedded in technology [START_REF] Zander | Knowledge and the Speed of the Transfer and Imitation of Organizational Capabilities: An Empirical Test[END_REF]. According to Gupta and Govindarajan Gupta [START_REF] Gupta | Knowledge flows within multinational corporations[END_REF], the absorptive capacity of the receiving unit is the most significant factor for successful transfer of knowledge in multinational companies. Here, knowledge inflow depends on the richness of transmission cannels, motivation to acquire knowledge, and capacity to absorb incoming knowledge. Hence, the absorptive capacity concerns the employees' ability and their motivation, and in particular the interaction between these [START_REF] Minbaeva | MNC knowledge transfer, subsidiary absorptive capacity, and HRM[END_REF]. Moreover, the absorptive capacity is claimed to develop cumulatively, building on the existing knowledge base [START_REF] Cohen | Absorptive Capacity: A New Perspective On Learning And Innovation[END_REF]. Some claim that theoretical arguments and empirical research addressing the individual or interpersonal levels antecedents of absorptive capacity are still lacking in this field of research [START_REF] Minbaeva | A retrospective on: MNC knowledge transfer, subsidiary absorptive capacity, and HRM[END_REF]. Furthermore, previous studies have shown that the implementation and outcome of management ideas such as Lean vary considerably across organizations [START_REF] Morris | Translating Management Ideas[END_REF][START_REF] Giroux | The Justification of Knowledge: Tracking the Translations of Quality[END_REF]. This implies that the knowledge these kinds of models represents, are 'translated' into a new context, where the recipient organization plays an active role in the adoption of practice and ideas. This will be addressed in the next section.

Knowledge transfer and context

In organizations, people have developed their own particular way of cooperating and sharing knowledge. In line with theory on absorptive capacity, the 'match' between new knowledge and the existing knowledge residing in the organization's social network will facilitate knowledge absorption. From this we would expect that social networks characterized by informal coordination and sharing of tacit knowledge would experience challenges when implementing formalized planning systems, since the existing knowledge base is not articulated, making it difficult to build on further by new and explicit knowledge. This dimension of knowledge acquisition can also be understood from a motivational point of view, as people will be motivated to acquire knowledge that fits their existing working practice and knowledge [START_REF] Minbaeva | MNC knowledge transfer, subsidiary absorptive capacity, and HRM[END_REF]. Hence, the motivation to acquire knowledge, and thus the absorptive capacity, is dependent on the social context. This study addresses the gap in the literature regarding contextualization of absorptive capacity, and in particular, the translation of management practices and ideas, where previous studies have been at a higher level of abstraction. We contribute filling the gap by providing a case study of implementation of Lean Project Planning (LPP) in an ETO shipbuilding environment. The difference in context is addressed by studying the implementation of LPP in two shipyards. In the following, we will briefly describe LPP, which represents the knowledge that is sought introduced and implemented at these shipyards.

Lean project planning (LPP)

LPP is based on Lean thinking [START_REF] Womack | Lean thinking: banish waste and create wealth in your corporation[END_REF] adapted to construction industry (Lean Construction) including elements from Last Planner System (LPS) [START_REF] Ballard | The last planner system of production control[END_REF] and Earned Value Management (EVM) [START_REF] Sumara | Earned value-the next generation-a practical application for commercial projects[END_REF].

Lean Thinking is represented here by Plan Do Check Act (PDCA) cycle, a basic problem-solving approach, which in the LPP context involves making problems visible, finding proper solutions, checking the results and acting on deviations [START_REF] Sobek | Understanding A3 thinking: a critical component of Toyota's PDCA management system[END_REF].

Lean Construction applies production-based ideas from lean thinking to project delivery within construction industry [START_REF] Koskela | Application of the New Production Philosophy to Contruction[END_REF]. In such projects, lean changes the way project is managed during the building process. Lean Construction extends from the objectives of a lean production system -maximize value and minimize waste -to specific techniques, and applies them in a new project delivery process. Lean Construction is particularly useful on complex, uncertain and quick projects. It challenges the belief that there must always be trade-offs between time, cost, and quality. Since the 1990s, lean construction community recognized the need for a change in the way traditional project management plan and measure activities in a project.

LPS is a planning tool intended to increase planning reliability by decreasing workflow variability, through recognizing and removing activity constraints, identifying root causes for non-completion of plans and monitoring its improvement by means of Percent Plan Complete (PPC) [START_REF] Ballard | An update onlast planner[END_REF]. LPS is a way to involve the 'last planner'the last link in the decision chainwithin the planning process by making 'promises' and then measure the percent of completed activities out of the promised ones (PPC) [START_REF] Olano | Understanding the relationship between planning reliability and and Schedule performance: A case study[END_REF].

EVM is a technique used within the planning system for measuring the progress of a project by comparing the baseline of the project with reported physical results, the resources consumed and the remaining hours to the completion per activity [START_REF] Sumara | Earned value-the next generation-a practical application for commercial projects[END_REF]. A good performance metrics used by EVM is the Cost Performance Index (CPI) used to calculate and predict cost at completion of the project within a finite range of values after only 15-20 per cent completion of the project [START_REF] Flemming | Using Earned Value Management[END_REF].

Each of the elements above has an important role in the LPP. PDCA involves identifying problems, find solutions and check the results. In LPP this is done in weekly meetings, starting with checking the status of previous week's planned activities. LPS is central for involving people within the planning process in order to achieve reliable promises and identifying problems in the near future. Important here is to involve the last link in the decision process, e.g. foremen as well as facilitating good communication and information flow between project participants. EVM contributes to making visible the progress and earned value at any stages during the building process.

Methodology

In this study, we aim at contributing to filling the gaps in the literature by studying the implementation of LPP in an ETO production environment, and where the differences in context are addressed. Despite having thorough knowledge of the LPP tool, the implementation of the tool is explorative in its nature, making a case study design appropriate [START_REF] Yin | Case study research: design and methods[END_REF]. Two shipyards are chosen as cases in this study: shipyard A and B. These shipyards were originally separate companies that were acquired by a larger group in the 1990s. They have, however, operated to a large extent as separate entities where most activities as design, engineering and production were carried out locally. Several years ago, the shipbuilding group started a centralization process by taking electro, design, piping, and accommodation departments outside shipyards and recreated them as distinct entities. This reorganization, together with the production of the hull outside Norway, created new challenges for the planning process. The present study involves a comparative research setting where the implementation process at the two shipyards is compared in order to find the relationship between barriers and the success of implementation. Data is collected through participation in meetings and in-depth semi structured interviews employees in the head office and the two shipyards (three sites). Internal reports, minutes of meetings, and presentations constitutes additional data sources. Fur-thermore, one of the authors is the founder of LPP and has been involved in the implementation process at shipyard A. The interviews and the document study were aimed at revealing what parts of the LPP was sought implemented, how the implementation process was carried out and what kind of obstacles was experienced in the process. Furthermore, the planning systems and processes used before the implementation were mapped. Finally, the respondents were asked to reflect upon the reasons for the difficulties they experienced in the process.

4

Contextthe situation before implementation

One of the most important characteristic of Norwegian shipbuilding industry is its flexibility, which gives customers the possibility to decide many features of the vessel quite late during the building process [START_REF] Semini | Strategies for customized shipbuilding with different customer order decoupling points[END_REF]. Maintaining this flexibility while dealing with increased complexity of vessels, competition on shorter delivery periods, and lower building prices, involves a constant focus on improving all processes in the building projects. The whole shipbuilding process is performed through a concurrent engineering approach, which implies that production of any part of the vessel can be started while the engineering phase is still being in progress. In concurrent shipbuilding, engineering, procurement and production activities are performed in near concurrency throughout the project executionin contrast to the sequential approach where the vessel is engineered, equipment is ordered and then start the production process. The concurrent process, the participation of several different entities (internal and external), and the geographically distributed value chain (hull production outside Norway) represent demanding conditions for the implementation of a reliable planning system. In this study the emphasis is on the planning process for the outfitting phase of the project. The outfitting phase is defined as the stage in which some of the last components are mounted on board, before the vessel testing phase. The number of participants during the outfitting phase in each project varies from 200-700 workers belonging to different specializations (steel workers, piping, accommodation, electro, etc.).

Before the LPP implementation, both shipyards were generally able to meet the requirements regarding cost and delivery times. This can be traced back to the long experience of the production workers, who were able to make prompt decisions based on their experience and tacit knowledge. Both shipyards were using formalized planning systems only to a moderate extent. In particular, the participation of people from production in the planning process was limited or absent, while a dedicated person, the Planner, created the plans based on data from previous projects. Furthermore, there were no recordkeeping of deviations in order to avoid recurrence of mistakes at both shipyards. In both shipyards, the communication flow took place mainly through informal channels.

However, there were some differences between the two shipyards regarding the structure and formalism of meetings. Shipyard B had before the implementation regular planning meetings on a weekly basis. From these meetings Minutes of meetings (MOM) were written by the Planner and sent to designated persons within the project. Such structure in meetings was not present at Shipyard A, where the meetings were more informally organized, and where MOM was seldom written. Furthermore, in shipyard B there existed a planning tool to follow the evolution of the projects in terms of resources. The diagrams were however based on the Planner's experience. In Shipyard A there was lack of formal control over the projects regarding resources and time, and decisions were made based on people's experience.

Implementation into two different production contexts

Demands of shorter building periods, organizational changes (centralization), and coordinating challenges due to the distributed production process (foreign hull producing shipyard and local shipyard for outfitting), motivated these shipyards to look into their planning processes. LPP was implemented and adapted with the purpose of enhancing communication within the planning process [START_REF] Semini | Strategies for customized shipbuilding with different customer order decoupling points[END_REF]. This was done by standardizing the meeting structure, providing physical progress measurement, and proactively eliminating barriers that could affect completion of any activity. Another purpose for implementing this tool was to achieve commitment to the project plans by involving people executing the activities within the planning process. Shipyard A succeeded in implementing the most important aspects of LPP as described above. Participation was achieved by asking foremen to prepare week plans with activities that can be executed by own team during the next period, so that they were committed to the plan and felt responsibility to complete activities as planned. Furthermore, Discipline Coordinators (DC's) were formally invited to weekly meetings, and the meetings became more structured and formalized. Moreover, deviations became recorded systemically on the week plan and followed up by designated people. In general, communication flow in projects was improved, as more people were involved in the planning process, as well as increased commitment through written plans. The results of implementing this tool at Shipyard A were very good, which led the management of the shipbuilding group to encourage the other shipyards to implement LPP.

The second shipyard in this study, Shipyard B, approached the LPP differently than shipyard A. After being introduced to the planning tool, they tried it for a few months and then decided that it is not fitted for their way of working. Instead, they reinforced the usual meeting procedure with some small adjustments: The General Plan was updated based in the reporting from own Discipline (DCs) and presented during the weekly meeting. Furthermore, an adapted EVM version was introduced. However, this was adapted only at a general plan level, not at a lower level in the project organization. Moreover, deviation was only discussed and solved in connection with formal, however mostly in informal meetings, but there were no records made in order to prevent reoccurrence of the deviations.

Discussion and conclusions

The purpose of this paper was to study the implementation of LPP in the shipbuilding industry from a knowledge perspective. In particular, we wanted to analyze the role of context in the implementation process, which has been done by studying the implementation of LPP at two separate shipyards in the same shipbuilding group. We found that Shipyard B had somewhat more formalized planning routines than Shipyard A before implementation of LPP. Hence, we should expect that the knowledge base of Shipyard B should be more adapted to the new knowledge represented by LPP. However, this study finds that this has not been the case. On the contrary, the implementation of LPP has so far been more successful at Shipyard A. Literature on absorptive capacity emphasize the importance of interaction between the knowledge base and employees' motivation In our study, we found that there were differences regarding motivation at the management level. In shipyard A, the manager participated actively in developing LPP and implementing the planning tool at the shipyard. At Shipyard B, the managerial level found that the existing planning tool functioned satisfactory, and hence were not motivated to implement a new and more formalized tool. This finding illustrates the importance of the interaction between both knowledge and motivation for a successful implementation. Furthermore, the lack of formalized planning systems at Shipyard A could be considered as an advantage when implementing a new planning tool, as this organization may be more open to new ways for organizing working processes. Finally, our findings may indicate that these two shipyards despite of being a part of the same shipbuilding group residing in a cluster characterized by shared norms for knowledge sharing and extensive use of informal coordination [START_REF] Halse | Governance and transformation of clusters: theoretical models and the case of the maritime cluster in Mid-West Norway[END_REF], represent two different organization cultures. Based on preliminary findings, we can deduce that the organizational culture at Shipyard A emerges as more open to external impulses than at Shipyard B. The role of the organizational culture should be addressed in further studies. Furthermore, as this study is carried out in a relatively early stage of the implementation process, data should be collected at later stages in the implementation process, preferably including other shipyards in the group implementing LPP.


Bjørnar Henriksen
email: bjornar.henriksen@sintef.no

Carl Christian Røstad
email: carl.c.rostad@sintef.no

Paths for Modularization

Keywords: Product development, modularization, boating industry

de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Customization is one of the potentially most important competitive advantages for manufacturers in high cost countries such as Norway, especially when it is combined with innovations and frequent product introductions. However, this is challenging for example in the design and development of boats when also efficient production processes are required. "Mass customization" and modularized design/production would normally be key elements in a strategy to meet such challenges. The overall objective for the R&D project "Marine Platform" is to reveal, create and combine the different presumptions and requirements into efficient development and production processes for boats. This is based on a new approach to design and the development of flexible standardized structural platforms as a basis for defined interphases for the different modules in boats. This then leads to new approaches to production and customization improving the companies' competitiveness. In our definitions of modules we have to go behind the traditional view of modules as physical parts and systems. Modularized processes, both in product development and production, and increasingly modularized knowledge (e.g documentation) are emphasized in modularization. Even though all of the above perspectives are interrelated and should be covered in a holistic modularization strategy, they are often not explicitly described and approached. An important part of the project is to develop methodologies and solutions enabling these objectives.

The purpose of this conceptual paper is to illustrate different ways modularization could be approached using cases from the boatbuilding industry, where the overall aim is to enable rapid product development processes. The paper is based on a R&D project involving manufacturers of leisure boats and boats for the professional markets. The project is at an early stage and so far the activities have mainly been to develop hypothesis, challenges, and how to approach them in concrete contexts. The project is closely related to what is happening in the companies (case studies) and the researchers aim to participate in the product development processes in order to improve them through action research. Literature studies have also been important for the project (and this paper) at this early stage.

Section 2 presents theoretical perspectives on innovation and modularization. Section 3 presents the R&D-project while Section 4 focuses the different focus areas in the modularization of a structural platform for boats. Section 5 concludes.

Theoretical Perspectives

Product development and modularization

Module-based design funded on platform-thinking enables faster development processes e.g. through reuse of solutions. We can also assure robust design solutions from modules that have been tested and optimized over a long period of time. Modularity allows part of the product to be made in volume as standard modules while product distinctiveness is achieved through combinations or modifications of modules [START_REF] Duray | Mass Customizers use of inventory, planning techniques and channel management[END_REF]. Modularization could bridge the advantages of: (1) standardization and rationalization, (2) customization and flexibility, and (3) reducing complexity [START_REF] Ericsson | Controlling Design Variants: Modular Product Platforms[END_REF]. The cost effects through reduced product development lead time and volume effects from standardization are important, but there are also revenue aspects of modularization: With a modular product platform structure, a set of building blocks (modules) are created where a great number of final products can be built, without increasing a company's internal complexity.

Parallel development activities are possible once the interfaces between the modules have been defined, and subsequent work conforms to the established interface specifications [START_REF] Stone | A heuristic method for identifying modules for product architectures. A heuristic method for identifying modules for product architectures[END_REF]. This reduces overall development time and resource requirements by eliminating the time-consuming redesigns when component interfaces are not fully defined and standardized during component development processes [START_REF] Sanchez | Using modularity to manage the interactions of technical and industrial design[END_REF].

Components and functions

We often find module-based design within incremental product development, where e.g. not all innovations or "novelties" are introduced at the same time. However, if modularity is identified and exploited in the initial conceptual or reverse engineering effort, the immediate product design reaps benefits in several strategically important areas [START_REF] Røstad | Attacking the Critical Parts in Product Development -Marine Platform, Building Flexible Structural Elements for Boats Preceedings APMS[END_REF]. However, an early focus on products and components could freeze product architecture and solutions, making it less flexible for future requirements. Products are normally supposed to fulfill functions or requirements defined by "someone". This could be from standards or regulations, but most often this is about meeting customer requirements. A function oriented approach implies focus on functions and organizing/prioritizing them before the physical function containers are defined. This could be perceived as a demanding and theoretical process, but today modularization based on functionality has become a common approach and methods have been introduced to cut out a module from function structures using module heuristics [START_REF] Stone | A heuristic method for identifying modules for product architectures. A heuristic method for identifying modules for product architectures[END_REF]. These methods, such as Modular Function Deployment (MFD™), identify modules from a functional model of a product, create rough geometric layouts and group products into families based on function [START_REF] Ericsson | Controlling Design Variants: Modular Product Platforms[END_REF]. Rather than a fixed product platform upon which derivative products are created through substitution of add-on modules, this approach permits the platform itself to be one of several possible options. After comparing function structures for common and unique functions, rules are applied to determine possible modules. This "inverse" process defines possible architectures. This approach increase the flexibility as it also represents a modularization of the basic platform [START_REF] Dahmus | Modular product architecture[END_REF].

Modules -knowledge containers

A systematic approach needs knowledge from people that know customer demands, service requirements, and from those producing the products. Concurrent engineering could be a key to mobilize and capture this knowledge [START_REF] Jo | Principles of concurrent engineering[END_REF]. An important part of the knowledge of the company is embedded in the products and reusing modules knowledge saves time and money. Also, the reuse of engineering specifications, testing, process engineering etc, may lead to the desired effects by blurring the boundary between knowledge management and traditional modularization [START_REF] Sanchez | Modularity, Flexibility, and Knowledge Management in Product and Organization Design[END_REF]. The tendency towards a more abstract understanding of modularity is further strengthened by the fact that modularization in an industrial context can be seen as reuse of engineering and employee resources for companies that are increasingly aware of knowledge as a competitive advantage [START_REF] Sanchez | Modularity, Flexibility, and Knowledge Management in Product and Organization Design[END_REF]. An important part of the knowledge of the company is embedded in the products and reusing modules. It is not necessarily the finished, physical modules that are reused in order to gain the benefits. Also, so-called intellectual reuse of earlier stages, like reuse of engineering specifications, testing, process engineering etc, may lead to the desired effects by blurring the boundary between knowledge management and traditional modularization [START_REF] Miller | Design for Integration in Manufacturing[END_REF].

Holistic approach to modularization

To get the desired effect of module-based design processes they have to be standardized in a way that matches the requirements from the physical products and modules.

Processes could be production, but also product development or administrative processes such as documentation and system-support. Also the knowledge modules are premises e.g. for production or product development since they could give input on for example cost efficiency of the processes.

For the product development process modularization could give time and cost savings in addition to quality improvements since modules could be developed separately through testing, modules could be reused in subsequent development processes etc. One of the advantages of a holistic modularized product strategy is that modules could be "sub optimized" without risking reducing the performance of other modules or the product as a whole. Modules and platforms are terms closely related and often mixed. One distinction is that while a module has a product-or function focus, platform are often more abstract, related to processes or basic principles. A platform could be basic geometry (e.g space between components), fixation, materials, common ways of dealing with interfaces and tolerance. In this way a platform have a longer life time than modules and could as is the case for the Marine Platform contain several modules.

The Marine Platform project

Marine Platform is a 4-year R&D project co-financed by The Norwegian Research Council that started in 2012. The overall objective is to radically improve the product development process focusing on the critical and resource demanding phases related to the structural elements of the boat. The project aims to define the premises and solutions for a flexible structural platform.

The project has four Norwegian industrial partners, two SMEs producing for leisure boat markets, one large company producing for the professional market, and a SME supplier which is a key actor in the boatbuilding industry as it is the biggest and most important supplier of their products in the Scandinavian boatbuilding industry. The supplier is within the mechanical engineering industry, but still has many of the same characteristics of craft manufacturing as the other partners.

SINTEF is project coordinator and two other research partners are also contributing to the action research, namely The University of Agder and Inventas.

4

Different paths towards a flexible structural platform

Criteria for structural platforms

Flexibility and modularization enabling rapid product development can be achieved by using the different perspectives on modularization in different areas. In the Marine Platform project business cases have been defined for each industrial. This provides the objective for the research carried out and thus results in a higher technology readiness level [START_REF] Mankins | Technology Readiness Levels. White paper, NASA Office of Space Access and Technology[END_REF]. The business cases are strongly revolving around how to make the development process for new models more efficient and more cost-effective in addition to catering for the ability to customize the products and thereby competitively fulfilling customer requirements. This requires a study of success factors, enablers, capabilities, the possible configurations and the possible critical issues [START_REF] Corti | Proposal of a Reference Framework to integrate Sustainability and Mass Customization in a Production Paradigm[END_REF].

As the knowledge aspect is crucial for modularization, an important criteria for modularity is that performance, data collection and knowledge could be linked to modules or be property-modules themselves in the product architecture.

Investigating and developing a structural platform that can act as a basis for several different models is well known in other industries like the automotive sector. However, with regard to boat manufacturing where there are very high demands for customization and where the number of boats sold of one model is significantly lower than in other industries, the need for a flexible structural platform arises. Such a structural platform can both consist of the hull/inner-liner/support structure themselves and modules on the boat acting as structural components providing stability and strength.

In the following, the project's focus-areas for establishing a flexible structural platform for boats are presented. Specifically, this paper addresses the following areas; standardization and outsourcing, material technology and adaptive process moulding.

Standardization and outsourcing as basis for a structural platform

Identifying structural properties for interiors, furniture, doors, windows, bulkheads are just some examples that to a large degree will have to be carried out in cooperation with suppliers and where one can achieve simplification through standardization and uniform quality requirements. By establishing concise structural properties and re-quirements for different modules and components in a boat, it will be easier to create requirement specifications to suppliers. The establishment will also make it easier and more efficient to identify suppliers and products that adhere to the sought-after product properties. Standardization also addresses strength requirements which in turn more clearly defines the single components and modules and thereby simplifies the work on the overall structure in boats. The main advantages with standardization are that a company achieve a holistic approach and have more available data with regards to a boat's structure. The greatest challenge is the amount of work needed in order to standardize, especially in craft manufacturing where there are many unique and oneof-a-kind solutions developed for single products.

Standardization also must capture customer needs of today and tomorrow in defined (and not defined) market segments. The Concurrent Innovation Process has been developed for involving customers and document needs and requirements. One of the boat producers used this methodology as basis for developing modularized concepts for a new range of boats for the professional markets and proved that common platform based on standardized solutions was a viable approach.

The project addresses standards and common solutions for interfaces, material solutions etc. This enables a higher degree of flexibility in supply chains and outsourcing, but will require extensive documentation and a general acceptance of standards.

Material technology as basis for a structural platform

By focusing on material properties, new material-solutions that provide strength and structural properties are within reach. Also, materials as enablers for modularization are equally important. Different materials with different kinds of properties can have different structural functions that may be utilized in order to ensure flexibility and structure. Examples are self-supported hulls, use of innerliners or grids.

New laminates and new or adapted materials provide greater possibilities to avoid the cost-driver of special reinforcement like ribs and/or innerliners. Also, a fact-based approach to the use of materials is needed in order to avoid over-dimensioning and excessive use of materials, resulting in higher material costs and e.g. heavier products (resulting in e.g. higher energy consumption). However, it should be noted that e.g. leisure boats are built based on strict international standards where the designers are restricted in choosing e.g. material thicknesses. One of the project's aims is to contribute towards new standard developments. The project has carried out several tests on new materials showing the possibilities that may be possible. One of the first business cases has been to develop, simulate and build a new modular boat using aluminum. The main objective of this endeavor was to take a new modular approach to the use of a fairly known material in the boating industry. Marine Platform also has a focus on laminate composites. Being able to describe and understand the relationship between the structure and composition of a material, its processing parameters and its properties is an important knowledge module for flexible and effective product developments of boats.

However, material testing and documentation is resource demanding and Marine Platform is now investigating methods for "multi-testing". Through a combination of lab-tests, reuse and simulation the aim is to be able to test and document a larger amount of different material properties from one panel.

Adaptive moulds as basis for a structural platform

Usually a new boat-model is developed on the drawing board and a prototype is made. The prototype is usually made as a mock-up and will later form the basis for cutting e.g. the hull on order to make a mould. However, the mould is very inflexible as you can only produce the specific hull. The ultimate objective of the project is to explore and develop adaptive moulds that fulfill the requirements for design, structure and strength. In theory this indicates that it should be possible to develop adaptive moulds that can facilitate an unlimited number of boat-designs by splitting the boatdesign into modules. The project aims to develop and prove that adaptive moulds for smaller ranges of boats are possible and the work so far seems to confirm this. As the advances are still on a theoretical level there is still work to do in the business case connected to high-speed boats.

Several advances seem promising and fitting as starters for adaptive moulding. Using additive manufacturing is one such approach [START_REF] Dormal | A new technology for the manufacturing of large prototype injection moulds: LLCC (Laminated Laser Cut Cavities)[END_REF]. Here it is possible to create prototypes without cutting moulds. However, the sizes available for additive manufacturing will pose some challenges and one need to address interface-issues between modules made in order to create a structure that might be used as template for build 1 of the boat. In effect, the project has found that additive manufacturing is usable for prototyping and production of smaller hull-parts and modules.

A promising approach is flatbeds. Here one has a set of moulds that ensures that the basic requirements for a boat are addressed. The greatest advantages will be that it will no longer be necessary to cut moulds, thus removing a very costly and timeconsuming process. It will also provide the possibility to merge modules that can create new models much more rapidly than before. "Flat bed methodologies" are showing great prospects, however there is still a long way to achieve what the project are aiming for; the flexible adaptive structural platform.

Conclusion

The flexibility and the cost effective aspects enabled by modularity could be an important driver for cost effective product development. In Marine Platform the focus is on the structural platform of the boats and the project has identified several paths for this. These paths' could be based on modularity in products/services, processes, and increasingly important, knowledge. In Marine Platform we have shown how standardization and outsourcing could represent a cost effective way to distribute development cost. Focus on material technology could give us a set of solutions representing modules in a structural platform for boats. Moulds from modules could also be a basis for modularity.

In Marine Platform all of these focus areas for modularity are combined and investigated. However, the basic element is modularized knowledge. Documentation and knowledge is fundamental for standards, for material solutions and how to design/assemble mould elements (modules). It is the knowledge modules that are the main enabler for fast creating the structural elements of the boats. The knowledge modules are also much more proprietary than the physical modules, hence more difficult to copy by competitors.

Fig 1

 1 Fig 1 Component oriented modularization

Fig 2

 2 Fig 2 Function oriented modularization

Fig 3

 3 Fig 3 Holistic approach to modularization