Gandhi

Characteristics of Green BIM: process and information management requirements

Keywords: Building information modeling, environmental sustainable design, information management, collaboration

In this paper, the authors explore the characteristics and requirements of digitally supported "green" building design. Well planned, integrated and interdisciplinary digital design practices play a vital role in the iterative processes of sustainable building design. Unlike traditional ways of working, the management of design information and process integration in green building design involves a wider range and a larger number of consultants utilizing sophisticated environmental modelling and analysis systems. To understand the complexities surrounding information management in this context, the authors focus on issues relating to: 1) information exchange and model management, and 2) multidisciplinary design process coordination. Different aspects of sustainable design modelling methodologies are explored in relation to technology requirements, information exchange, and multi-disciplinary collaboration. Finally, the literature is synthesised in a conceptual roadmap framing the key factors identified by the study.

Introduction

The construction industry has long been aware of its contribution towards CO2 emissions and is now shifting towards more sustainable design solutions. Consequently, today"s AEC projects (architectural, engineering and construction) often require the use of advanced information technology (IT) to address complex building system dependencies and interdisciplinary design development processes that meet expectations of environmentally sustainable design (ESD) and the information requirements of green building. The application of building information modelling (BIM) and associated collaboration technologies (e.g., XML schemas, iCloud, etc.) represents a paradigm shift. "Green BIM" has thus been coined to describe the convergence of two key trends, green buildings and BIM. Green BIM is emerging as a new form of project design and delivery, where industry is still trying to grasp its implications. The required level of coordination between different organisations during Green BIM design processes depends on the complexity of the building [START_REF] Hossain | Communications and coordination in construction projects[END_REF]. Building development projects that employ ESD strategies and target maximum GBC (green building certification) credits arguably represent a higher order of complexity, particularly those utilising intelligent building systems. Further, in this context, integrated design processes and accreditation procedures often increase the number of participating stakeholder organisations working in synchronous collaboration. Such projects have high levels of process, activity and task interdependencies, and consequently information exchange between collaborating design firms is arguably more complex.

Not surprisingly, the rate of adoption of BIM technologies on green building design projects has increased in recent years [START_REF] Kriegel | Green BIM[END_REF]. Properly adopted, BIM promotes buildings of higher quality, with faster project delivery and at lower cost [START_REF] Lavikka | Towards coordinated BIM based design and construction process[END_REF]. Yet, whilst this methodology has facilitated innovations in sustainable design (see e.g., [START_REF] Kriegel | Green BIM[END_REF][START_REF] Eastman | BIM Handbook: A Guide to Building Information Modeling for Owners, Managers, Designers[END_REF]) and in optimising green building accreditation [START_REF] Azhar | BIM for sustainable design: results of an industry survey[END_REF][START_REF] Jupp | Clarifying the role of Building Information Modelling in Green Building Certification[END_REF] its full deployment is hindered by traditional work processes, business models, and industry fragmentation [START_REF] Kiviniemi | The Effects of Integrated BIM in Processes and Business Models[END_REF]. Green BIM must not only overcome the adverse effects of entrenched industry methods but also new ones such as incomplete implementations of the BIM methodology. Thus, the coordination of reciprocal design task interdependencies, the management of inter-organisational processes and the sharing of digital design information represent significant challenges [START_REF] Lavikka | Towards coordinated BIM based design and construction process[END_REF].

This paper explores the characteristics and requirements of information management for Green BIM in a literature based study. Sect. 2 describes the main attributes of Green BIM. In Sect. 3, the paper presents the research related to information management including discipline specific modelling requirements for sustainable design and associated challenges to information exchange (Sect. 3.1), and multi-disciplinary collaboration across organisational boundaries and the challenges surrounding task interdependencies (Sect. 3.2). The authors discuss their characteristics and requirements in relation to methodologies for sustainable design modelling. In Sect. 4, the authors present the main elements of Green BIM, synthesising the literature into a conceptual roadmap that identifies the relationships between each factor. Sect. 5 provides conclusions and directions for future research.

What is Green BIM?

A variety of definitions of Green BIM exists in the literature, (e.g., [START_REF] Kriegel | Green BIM[END_REF][START_REF] Eastman | BIM Handbook: A Guide to Building Information Modeling for Owners, Managers, Designers[END_REF]). The authors define Green BIM as being based on three conceptual pillars: (1) ESD principles, (2) optimisation of GBC credits, and (3) integrated building systems and design processes supported by object-based modelling and analysis tools. The intention of ESD is to "eliminate negative environmental impact completely through skilful, sensitive design" [START_REF] Mclennan | The philosophy of sustainable design: The future of architecture[END_REF]. According to its principle objectives, ESD should result in more comprehensive and assessable sustainable design solutions for the built environment. ESD methodologies target five key areas of sustainability relative to building type including 1) climate, culture and place, 2) reduction of resource consumption, 3) use of local resources, 4) efficient use of man-made systems, and 5) application of renewable energy systems. Furthermore, building systems integration is one of the main goals of ESD, and the complexity of such a task requires higher levels of process and stakeholder integration. GBC systems such as Australia"s Green Star [START_REF] Gbca | Green Building Council Australia[END_REF] and the US LEED [10] system are generally hierarchically awarded credit-based systems assessing a range of criteria, including e.g., sustainable sites, water efficiency, energy use, and quality of atmosphere, material resources, indoor environmental quality, and innovation in design ( [START_REF] Gbca | Green Building Council Australia[END_REF]10]). To assess these criteria during the design stages it is necessary to model, simulate and analyse the virtual building. Object oriented or component based computer aided design (CAD) assists in the generation and coordination of semantically rich building information models. BIM technologies are able to provide more accurate and reliable building data, support inter-organisational collaboration, provide simulation and analysis, and accelerate production of documentation drawings [START_REF] Eastman | BIM Handbook: A Guide to Building Information Modeling for Owners, Managers, Designers[END_REF][START_REF] Azhar | BIM for sustainable design: results of an industry survey[END_REF]. Azhar et al. [START_REF] Azhar | Building information modeling for sustainable design and LEED® rating analysis[END_REF] shows that more than half of GBC (LEED) credits can be facilitated by BIM technologies. A virtual prototype integrated with discipline specific information models can be used to simulate ESD alternatives and optimise the final solution. In this way, BIM facilitates multidisciplinary collaborative working activities between the design team members [START_REF] Succar | Building information modelling framework: A research and delivery foundation for industry stakeholders[END_REF]; however it can increase the complexity of information management due to the amount of information generated and the complexities surrounding interoperability and the timing of information exchange [START_REF] Azhar | BIM for sustainable design: results of an industry survey[END_REF][START_REF] Bedp | Issues Paper : Australian Council of Built Environment Design Professions BEDP[END_REF].

Green BIM therefore requires explicit, precise information for building system integration and evaluation. Theoretically, the methodologies and technical capabilities of Green BIM should enable major improvements to both design processes and products. However there are two key challenges surrounding Green BIM: (1) the involvement of a wider diversity of the design team members from different disciplines and organisations, and (2) the high level of interdependencies between processes, activities and tasks (e.g., a change in the facade materials creates a need to change the architectural design model, the structural design model and possibly also the mechanical, electrical and hydraulic models). Sodagar and Fieldson, [START_REF] Sodagar | Towards a sustainable construction practice[END_REF] highlight the challenges of an integrated approach to sustainable design during tentative and iterative design processes. Involvement of a wider variety of the design team participants from the early project phases also means their potential continued participation through to project delivery [START_REF] Häkkinen | Barriers and drivers for sustainable building[END_REF]. Figure 1 illustrates the required participation of design disciplines and the timing of their involvement in a Green BIM project. As the figure shows, Green BIM requires the involvement of the owner, architect, a variety of engineers and consultants, contractors, suppliers and manufacturers as well as an accredited professional (AP) representing the designated green certification body [10, [START_REF] Gbca | Green Building Council Australia[END_REF][START_REF]Integrated Project Delivery: A Guide. version 1[END_REF].

Characteristics and requirements of Green BIM

The information management demands of a multidisciplinary design process cannot be managed by a single stakeholder organisation. It requires a range of design, project and IT professionals to coordinate and unify the design domains of different building systems. A comprehensive understanding of the multi-level interconnections between technologies, people, project phases, processes and systems is needed to address the (sometimes competing) requirements of Green BIM. Effective information management practices must meet the demands of the continual generation, transmission, publishing, interpreting, storing and retrieving of a wide range of building design data. Green BIM requires consideration of the policy-, process-and technology-based elements that underpin the BIM methodology [START_REF] Jupp | Clarifying the role of Building Information Modelling in Green Building Certification[END_REF], as well as strategies for successful information management that can support knowledge transfer and translation in multi-disciplinary ESD collaborations [START_REF] Den Otter | Design team communication and design task complexity: The preference for dialogues[END_REF].

Information management

The underlying requirements of information management in Green BIM projects can be seen to relate to four variables: 1) number of participants exchanging information, 2) information standards, protocols and format, 3) timeliness of information exchange, and 4) roles and responsibilities when exchanging information. In addressing policy-based information management issues, various solutions have been suggested including contractual documents, exchange protocols, modelling standards, and specification of the level of detail (LoD) in modelling (such as those found in BIM management plan templates and frameworks specifying e.g., LoD 100 to LoD 500) [19]. Interoperable file exchange schemas can partially assist with the technical difficulties surrounding compatibility (e.g., .ifc, Gbxml, .dwg, Etc.), which enables the development of an integrated data rich model.

Precise and timely information is required to overcome the adverse effects of industry fragmentation during the design process, providing accurate and coordinated 3D models for Green BIM. Tzortzopoulos-Fazenda and Cooper [START_REF] Tzortzopoulos-Fazenda | Design management from a contractor's perspective: The need for clarity[END_REF] define design management as an ill-structured process and the day-to-day operating boundaries as being imprecise. Information exchange therefore, requires well-defined standards and protocols prior to commencement of the design process. Tracing the timeliness of design information for Green BIM projects and mapping this with the capabilities and interoperability requirements of ESD technologies is essential for understanding reciprocal task interdependencies within the design team. Figure 2 presents an example of the potential information exchange and communication patterns occurring during a Green BIM project, identifying a network of task interdependencies. Green BIM is dependent on the use of digital design technologies for the purposes of both product systems integration and design process integration -such integration can be better addressed if the elements of ESD and GBC are considered in parallel. This leads to the second topic of this section: multidisciplinary collaboration -including the inter-organisational task dependencies and information modelling requirements.

Multidisciplinary collaboration

Design researchers have studied a range of factors responsible for the complexity surrounding multidisciplinary design collaboration. In digital design collaborations, two concerns are identified as important, namely: 1) the representation, communication and coordination of electronic information [START_REF] Toth | Sky high and back again: the evolution of simulation-based design from aerospace to construction[END_REF], and 2) differences in discipline-specific design methodologies. Undefined BIM management practices and standards can result in design team members performing functions independently of each other, and increases in levels of complexity and uncertainty. This may then negatively impact on GBC outcomes despite the time, funds and effort invested. Figure 3 provides a snapshot of the type of interactions that occur between design team members during the development of sustainable building designs. Generally to attain GBC, accreditation is based on specified criteria; to achieve the desired results from the procedure, information must be generated by a range of consultants with expertise covering e.g., water harvesting, recycle-reuse, energy analysis, sustainable material resource, day light analysis and sustainable product development. The information generated must undergo many iterations of revision depending on project requirements and design challenges. Thus, Green BIM projects with high GBC rating objectives require detailed planning during project inception.

Rohracher [START_REF] Rohracher | Technology Analysis and Strategic Management[END_REF] explains that close interaction and a high level of compatibility between project participants are key necessities for ESD processes. However, a number of barriers to these necessities exist. With the high diversity of project stakeholders it is likely that individual design disciplines are located in different geographical locations and conditions. Like all projects, it may not always be possible to have close interaction with the entire project organization at any one time. In spite of the availability of advanced communication facilities, meeting agendas are difficult to define when projects are characterized by high levels of complexity, uncertainty and ambiguity. It is necessary to manage complexity and eliminate uncertainties resulting from unforeseen knock-on effects of design changes, which can also potentially identify unknown reciprocal task interdependencies [START_REF] Lavikka | Towards coordinated BIM based design and construction process[END_REF]. Consequently, extensive resources may be required to support collaboration within Green BIM projects resulting in expensive design and development processes. In the face of complexity and rising cost, team members may revert back to traditional practices.

In Green BIM projects, successful management and coordination requires a multidimensional approach. However, the research literature (see Luthra [START_REF] Luthra | Implementation of Building Information Modeling in Architectural Firms in India[END_REF]) reports a lack of appropriate BIM management frameworks, often resulting in the incomplete adoption of the methodology [START_REF] Lavikka | Towards coordinated BIM based design and construction process[END_REF]. Amongst the few available solutions addressing this issue, are the AIA"s [START_REF]Integrated Project Delivery: A Guide. version 1[END_REF][START_REF] Den Otter | Design team communication and design task complexity: The preference for dialogues[END_REF] guidelines to Integrated Project Delivery (IPD) and others such as the NATSPEC guidelines, VA BIM Guide and the AEC UK BIM Standard [START_REF]Integrated Project Delivery: A Guide. version 1[END_REF]19,[START_REF] Acg | Productivity in the buildings network: assessing the impacts of Building Information Models[END_REF][START_REF] Aec | AEC UK BIM Standard -A practical and pragmatic BIM standard for the Architectural, Engineering and Construction industry in the UK[END_REF][START_REF] Nasfa | Integrated Project Delivery for Public and Private Owners[END_REF][START_REF] Vabimguide | [END_REF]. In other work by London et al. [START_REF] London | Building information modelling project decision support framework[END_REF] a BIM process management framework is proposed, which focuses on enabling integrated design. However these frameworks fail to account for the specific technological and design process features of Green BIM. These generic frameworks ignore crucial links and interdependencies between the technical, policy and process components defining the ESD activities underpinning Green BIM.

Fig. 3. Multidisciplinary design collaboration for Green Building Certification

Furthermore, in spite of the increasing interest in sustainable design and digital design practices amongst industry professionals and researchers, much attention is directed toward the development of the technical means of integration (i.e IFC-based BIM platforms, web servers for information exchange etc.) and control oriented management systems (e.g., policies, certification programs, regulations, and contract requirements). Azhar et al. [START_REF] Azhar | Building information modeling for sustainable design and LEED® rating analysis[END_REF] have mapped BIM capabilities with GBC requirements (in this case LEED), but fail to identify a number of Green BIM requirements including the identification of task and informational interdependencies, and the main actors responsible for generating information to meet GBC criteria.. Consequently there is a need to attend to the process dimensions of Green BIM relative to existing work on sustainable design technologies and policies. In targeting the coordination of task interdependencies along with non-linear information transfer Volker and Prins [START_REF] Volker | Exploring the possibilities of correlating management with value in architectural design[END_REF]show how process-based mechanisms can facilitate information management and control outputs. However there is a lack of research that integrates the process, policy and technological components of a Green BIM methodology. It is therefore necessary to analyse and amend current approaches to Green BIM projects to help achieve desired GBC credits in a more effective and efficient manner.

Toward a Green BIM management framework

The literature review highlights a lack of research into the specific modelling requirements and related challenges surrounding simulation and analysis for Green BIM and its alignment with the relatively recent introduction of GBC processes. Modelling interdependencies between building systems remain a major challenge to the coordination of design processes (e.g., water efficiency analysis requires detailed modelling of multiple building systems, including MEP services, hydraulic equipment). A Green BIM management plan that is capable of supporting the progression of ESD throughout the design stages requires further consideration of information management practices, such as the specification of information exchange protocols, the LOD in ESD modelling, and software and interoperability requirements. Consequently design coordination must focus on ESD modelling, simulation and analysis with an emphasis on "co-design" methods.

In a bid to structure and rationalise the management and coordination issues of Green BIM, the authors have synthesised the related literature in a conceptual framework aimed at developing a Green BIM management methodology. Figure 4 describes the framework as a roadmap that structures the requirements of technology, policy and process management for Green BIM. The proposed roadmap organises these requirements from the initial stages of project planning to the final stages of design using the AIA"s (2007) definition of IPD project stages (Conceptualisation, Criteria Design, Detailed Design, and Implementation Documents). The inter-linking components described in the roadmap are as follows.

1) Conceptualisation Stage: During this stage, a "Green BIM Requirements Assessment" system is essential to project initiation. Client and project objectives for GBC and ESD must be identified in conjunction with the details of implementing BIM tools and processes, as well as IPD methods and contractual arrangements. Information and modelling standards, protocols, along with specification of the level of detail (LoD) throughout the design process, design team members responsible for generating information, and the ESD simulation and analysis requirements should be defined. To define these it is first necessary to identify the scope and purpose of the project before then: (a) assessing GBC criteria specifications, (b) identifying resources including key actors and assessing BIM capabilities for ESD and GBC by mapping criteria to BIM tools, and (c) assessing overall project organisation capabilities to achieve desired GBC targets. Once these requirements assessment activities have been achieved it is then possible to inform the development of IPD methods and contracts as well as provide the basis for a Green BIM methodology.

2) Criteria Design Stage: During this stage, it is crucial to develop the Green BIM implementation strategy; this procedure requires: (a) assessment of the feasibility of GBC/ ESD and BIM tools to achieve targeted credits, (b) identification of an ESD design activity plan that maps design participants with informational dependencies across modelling, simulation and analysis activities (e,g., water efficiency, energy efficiency, day light analysis and material resources), (c) define modelling standards and communication mediums, (d) refine information exchange protocols and assess interoperability requirements between architectural modelling and ESD team consultants before initiating the design process, and (e) map reciprocal ESD task interdependencies between design team participants relative to GBC criteria. Thus during the Criteria Design stage, detailed process stages, stage gates and a process management matrix (describing reciprocal task interdependencies) should be developed. This will assist in mapping interdependencies between design activity plan and discipline-specific BIM technologies with emphasis on ESD methods and analysis tools. As part of this mapping process, it is also necessary to consider the interoperability requirements of each software application. Once this strategy has been developed IPD contractual arrangements can be evaluated and updated so as to ensure that the targeted GBC credits can be achieved collaboratively. 3) Detailed Design Stage: The detailed design stage must be supported by a comprehensive process coordination plan that will define a Green BIM design management approach. Prior to initiating design there is a need to prepare a design activity plan, based on process management matrix aligning ESD objectives and design tasks with information requirements and stage gates of the GBC process. To produce and implement such a plan it is necessary to: (a) update stage gates for the detailed design process (b) map stages gates to and update the design activity and modelling plans as well as information protocols, (c) develop an ESD and GBC process coordination map, (d) define management roles and responsibilities, (d) monitor and evaluate resources, plans and protocols. These components of a Green BIM coordination plan can then be used to inform and update the overall methodology and design management system in an iterative way.

Conclusion

The literature reveals a number of critical elements of Green BIM encompassing technological, process and policy based attributes. Studies surrounding recent developments in digital modelling and analysis technologies show how they assist in informed decision making and meeting GBC procedures. Further, a range of studies documenting exemplar building projects provide evidence of Green BIM implementations and the challenges faced and achievements made. Numerous industry-driven BIM management protocols are also reported in the literature. Researchers conclude that it is necessary to recognise the significance of design management methodologies and the importance of supporting sustainable building design by addressing the key requirements of information modelling and exchange in multidisciplinary design environments. There is no evidence based research that proposed process stages for development of Green BIM. The process coordination and information management requirements identified here are inseparable elements and many of the vital decisions regarding these elements are defined in the early planning and design stages. Developing information management strategies, process stages based on ESD and GBC objectives are therefore pre-requisites of successful Green BIM.

Fig. 1 .

 1 Fig.1. Design team members in Green BIM project (Adapted from[START_REF] Den Otter | Design team communication and design task complexity: The preference for dialogues[END_REF]).

Fig. 2 .

 2 Fig. 2. Tracing task interdependencies of Green BIM

Fig. 4 .

 4 Fig. 4. Conceptual roadmap for Green BIM design management system


Claudia Eckert

Chris Earl

Safaa Lebjioui

Ola Isaksson

Components Margins through the Product Lifecycle

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

Introduction

Design is an iterative process. Many decisions have to be revisited and changed throughout the design process. This often involves changes to components that are considered finished. However, engineering change is not confined to design processes. It occurs through the entire life cycle of the product. [START_REF] Fricke | Coping with changes: causes, findings and strategies[END_REF] estimate that 30% of all work arises from changes of one form or another. Changes arise either from external factors, such as new requirements or advances in technology or are the result of other changes or problems with the state of the design. A change only needs to be made, if the existing design cannot meet the new requirements.

Most components or systems have the ability to absorb some degree of change. This arises from incorporating margins. These are added by different stakeholders for a variety of reasons. However how these margins are introduced and how they work in design have not been addressed in a unified manner in the context of managing change. After a discussion of relevant literature the paper introduces the concept of margins, defines key terms and types, and shows ways to model margins. The paper is set in the context of recent studies on engineering change such as [START_REF] Eckert | Change and customisation in complex engineering domains[END_REF] and [START_REF] Pasqual | Multilayer Network Model for Analysis and Management of Change Propagation[END_REF]. It addresses the role of margins at different phases of product development and through product lifecycle.

Background

One way to avoid problems with engineering design changes, is incorporating flexibility and adaptability into a products in the first place. This section provides a brief overview of the literature on design for flexibility and engineering change.

Design for flexibility

Product flexibility can be defined as "the degree of responsiveness (or adaptability) for any future change in a product design" [START_REF] Ross | The Tradespace Exploration Paradigm[END_REF]. [START_REF] Qureshi | Principles of Product Flexibility[END_REF] propose 17 different strategies to achieve flexibility in a product, grouped into four types: a modular approach, a special approach, an interface decoupling approach and an adjustability approach based on the principle of TRIZ (e.g. [START_REF] Altshuller | 40 Principles: Keys to Technical Innovation[END_REF], [START_REF] Martin | Design for Variety:Developing Standardized and Modularized Product Platform Architectures[END_REF]). The 17 th of Qureshi et al's strategic principles, referred to enabling "the device to respond to minor changes, by controlling the tuning of design parameters". Both [START_REF] Qureshi | Principles of Product Flexibility[END_REF][START_REF] Muir Wood | Product Form Evolution[END_REF] advocate assessing the flexibility of a product by systematically anticipating and rating the potential changes to 'future proof' the design. [START_REF] Ross | The Tradespace Exploration Paradigm[END_REF] advocate assessing the changeability of a system by mapping out the tradespace, i.e. the range of possible parameter values that provides potential solutions. Where the design sits within this tradespace, defines the product margins.

Engineering Change

Changes are ubiquitous through the product lifecycle of a design (see Figure 1 and [START_REF] Eckert | Knowledge requirements over long product lifecycles[END_REF] for a more detailed discussion). Almost all complex products are designed by modification from an existing product, so that engineering change starts right at the beginning of design processes and continues.throughout the pro-cess as adaptations are made to existing components until parts of the designs are frozen. The process of preparing a product for manufacturing typically also leads to frequent changes. Once a base product is produced, orders are placed for other versions of the product or requests are received for customisation. This may be covered by options from a defined set of configurations, but change to the underlying design might also be required. Products in operation and use are subject to changes through product upgrades. 2012) present a review. The processes of handling change and the challenges that arise from change propagation are similar regardless of the cause of the change or the phase of the design project [START_REF] Eckert | Change and customisation in complex engineering domains[END_REF]. The impact of changes is not limited to the product itself, but can affect the rest of the organisation through shared resources and interlinked processes [START_REF] Ariyo | Unpleasant surprises in the design of complex products: why do changes propagate?[END_REF][START_REF] Shankar | Reasons for change propagation: a case study in an automotive OEM[END_REF]. Change is difficult to predict, because it is inherently not deterministic, and involves people making decision about how to respond to the need for change [START_REF] Earl | Predictability of Change in Engineering: a Complexity View[END_REF]. Various tools have been developed to assist predicting the impact of change, through anticipating changes (Cohan et al. 2000), probabilistic links [START_REF] Clarkson | Predicting Change Propagation in Complex Design[END_REF] and network analysis [START_REF] Pasqual | Multilayer Network Model for Analysis and Management of Change Propagation[END_REF].

The state of components

Whether a change in one component (or system) will propagate to another component, depends both on the exact nature of the change and the current state of the component that is being changed. Each proposed change can be expressed as changes to one or more parameter of the component. Various parameters are associated with each component .These can become critical in the sense that small required changes (or combinations of changes) initiate significant changes in behaviour in components with linked parameters (Figure 2).

A generic model of margins

Margins occur in many guises through the lifecycle of a product. This section introduces a base definition before relating margins to other phenomena. For the purpose of this paper we define a margin as: "the extent to which a parameter value exceeds what it needs to meet its functional requirements regardless of the motivation for which the margin was included". Figure 3 illustrates the relationship between the base line parameters (heavy black outline) that are required and the actual component parameters (the grey shape with margins in several parameters). In addition the component might be subject to constraints. Note that the margined product exceeds constraints in the figure and is a non-viable design. Viable margined products sit within constraints.

Each component or subsystem of a product can be conceptualized along three dimensions: form (internal structure and configuration of features), function and material. By form we are referring both to external shape and internal (possibly micro) structure. The component carries out a specified function in the product, which is usually described in terms of performance parameters and other target parameters reflecting the component's role in the product. For the third dimension, a component is constructed from a particular material or combination of materials with their own inherent properties. The combination of these three dimensions creates a working component, and the parameters arising from each of the three dimensions are required to describe the component. Parameters in each dimension have their own type of margin, Individual parameters can be traded off against each other across the three categories (Figure 4) and margins allow this tradeoff.. The closer a component gets to its margins the less flexibility it has to absorb a change and make tradeoffs (Figure 5). Margins do not only reside with individual components, but also apply to subsystems and systems in a way that is not deduced from the margins on specific parameters of individual components. These system margins on system parameters, allow changes in response to changes in other system parameters or in the operating conditions and uses of the product. The margins to absorb different operating conditions and uses does not relate to the margins of individual components in a linear and predictable way. For example a change in the ambient temperature in operation can require direct changes to the product, like the introduction of isolation material, but can also affect the behaviour of individual components, e.g. through heat expansion.

Figure 5: Reduced margins for change

Changes can rarely be addressed in isolation and display complex interactions. For example a component might expand in the heat while at the same time the isola-tion material takes up some of the expansion space. The challenge lies in identifying these interlinking changes and managing them together in a coordinated way. Giffen et al. ( 2008) map out the relationship of change requests illustrating both how change requests to specific components are repeatedly rejected and how changes to specific components multiplies repeatedly across the system. A particular challenge arises when the same margins is affected by seemingly unconnected changes carried out in parallel.

Margins across the product lifecycle

Product margins need to be considered even before a specific design process starts. As companies aim to control the amount of innovation required for a new product [START_REF] Suh | Technology infusion: An assessment framework and case study[END_REF] and assess the risk associated with the planned innovations [START_REF] Suh | Technology Infusion for Complex Systems: A Framework and Case Study[END_REF], they need to plan when major changes to the design are to be carried out and therefore where margins are required. This helps avoid unplanned changes. It requires a detailed understanding of the dependency between components and systems, to estimate when knock-on changes are likely to force significant redesign and thereby unplanned innovation. The is complemented by a deliberate design for flexibility approach (see Ollinger an Stahovich 2001).

Planning product changes over longer periods of time is particularly critical in the context of platform design, as the margins of each component are different with regards to different products in the platform, as illustrated in Figure 6.

Figure 6: Margins in platform components

Margins are added or identified in the product in different forms through the design process, as illustrated in Figure 7. The evaluation of the starting design stands at the beginning of many 'new' design processes. This evaluation can refer to the existing test data as well as use and warranty data, which allows the designers to understand the actual parameter value of a component. This is used to access which components need to be redesigned and thus how much effort is involved in the new design. At the beginning of the design process companies identify the requirements for different parameters and often plan in room for growth, i.e. parameter margins which accommodate further changes to the re-quirements for an emerging design or changes in future generations or upgrades. These margins are used up as the design process progresses, often without the company having a clear picture of the margins still available on a component. This is particularly an issue when multiple components need to make use of the same margin and the designers may not be aware of their colleagues' decisions.

During the design process, testing begins with the aim of assessing whether a product can meet its requirements, rather than understanding exactly the extent of margins exist in a component. In some cases companies test products to destruction and thereby determine the actual margins on components. Virtual testing, i.e. computer simulation of test conditions on analysis models can also reveal the actual component margins. Test results require a certain degree of post-processing to ascertain the parameter margins. This appears to takes place rarely.

Figure 7: Margins throughout the product life cycles

Margins are often thought of as tolerances or associated boundaries designed into a component to accommodate variability in manufacturing and assembly. This is typically the angle on margins picked up in robust design, which is concerned with assuring the quality of a specific product in service (see [START_REF] Chen | A Procedure for Robust Design: Minimizing Variations Caused by Noise Factors and Control Factors[END_REF]. To reduce the risk of product failure in service it is necessary to understand the manufacturing variabilities or set them as hard requirements for suppliers. Products also require safety margins to cater for extreme working environments, for example cold weather and the potential misuse of the product by customers. To a certain extent this can be covered by certifying a product for a specified range of conditions and behaviours or by imposing warranty conditions on the product. However companies still want to be sure that their product is robust to potential misuse, because doing otherwise might compromise the integrity of their brand. Design margins are essentially the residue when these tolerances have been accommodated.

Products are designed to operate under a given range of conditions for a target life time, which is specified in the product warranty. In practice products are often used for different purposes than intended or for a much longer period than anticipated. How products behave after the end of their target life also plays an important part in brand reputation. In the past products have often exceeded their target life by many years, because the products were overdesigned with large margins and the excess cost could be passed on to customers. As mathematical analysis tools have been improving, companies now have a handle on these excess margins and can optimise the products for a particular situation. Optimised products are both cheaper and have better performance, but are more susceptible to negative effects of engineering change, as have lower, or potentially no, margins to absorb change.

To date, consideration of margins does not systematically capture or analyse margins. However, the information to do so exists to some extent in companies. Those responsible for the last changes affecting a particular margin, usually have a good understanding that a margin could become critical, but on the other hand do not have a means to flag this up. To capture margins systematically companies would need to capture the results from testing with regards to margins. If a test fails, companies it is necessary to determine exactly what contributed to the failure, i.e. which margin was exceeded. To gain a more detailed understanding the companies would need to engage in physical (or virtual) destructive testing.

Example

The design of a rear turbine structural frame for an aircraft jet engine clearly displays the problem with design margins [START_REF] Eckert | Product Property Margins: An underlying critical problem of engineering design[END_REF]. The function of the component is partially to ensure mechanical load transfer, structural stability and integrity of the turbine section, whilst contributing to aerodynamic performance (low drag and gas-flow control) of the gas passing through the section. Weight and cost targets are important, so the final design solution typically follows a design optimization effort.

The margins on the metal temperature are critical. Making the turbine frame out of a well known and understood material may be a cost efficient way to produce, but has a narrow upper boundary of allowable metal operating temperature, Since the performance of the new engine is often expected to be higher than that of previous designs, the gas temperature may increase. The margin to ensure structural integrity using the well known material consequently reduces and may vanish entirely.

The design team then faces several design options: (A) use another material, capable of withstanding the new gas temperature, which might be more expensive, and costly to produce and maintain. (B) alter the actual design, e.g. to select a cooled version of the turbine frame, and maintain the "simpler" material.

Comparing (A) and (B) reveal different behaviour from a design margins point of view. Alternative (A) can be made without too much interaction with other parts of the engine system, but still has a definite upper bound in thermal resistance and the material itself may be quite expensive. Alternative (B) impacts the engine system design to use cooling air (expensive), but uses a known and less costly material. From a margins point of view the upper boundary of thermal resistance may be less definite. If the gas temperature turns out to be higher that first expectedthe solution may be possible to manage without changing material.

In reality change in conditions happens throughout the development process. Preconditions such as operating design gas temperature are uncertain, and often sub-ject to change. Alternative (A) may seem to be a wise choice, whereas alternative (B) is more adjustable from a design perspective. This simpleyet realisticexample reveals several aspects of margins.

1. The need to represent margins of principally different design alternatives (material up-grade vs. alternative cooled design solution). 2. The need to manage dependencies between design components (the turbine frame) in a system (the jet engine) 3. The need to strategically analyse and predict consequences of change in loads and pre-requisites. The third aspect is crucial to make informed design decisions, and requires that the underlying design information actually contain information about margins. Today, the analytical ability to make such design simulation is limited, and often handled qualitatively using FMEA and FMECA type approaches for risk analysis.

Conclusions

Margins play important roles in engineering change processes under different guises, which, although related, are typically considered and modelled separately. These roles include:

 helping to predict the knock-on effects of changes;  assessing uncertainty concerning the properties and behaviour of the product and conditions of its use;  evaluating flexibility regarding the use, manufacture and assembly of the product;  tolerancing for manufacturing and assembly and the robustness implications.  Building in adaptability for future products To manage margins efficiently, the ability to model margins and eventually assess consequences of changes, first requires a sound understanding and adequate representation of underlying margins. Further, the relations and couplings between design components and system with regards to margins needs to be identifiable.

Further research is currently being conducted in several case studies on product planning and platform development to (a) see how industry is handling margins in practice and (b) explore the role of margin models in change predication. The goal of this research is describe margins in a suitable language and model margins in a way that can be linked to existing product representations. The objective is to use margins directly in change prediction.

Figure 1 :

 1 Figure 1: Changes throughout the product life cycles Engineering change has been looked at from several perspectives. Jarratt et al. (2012) present a review. The processes of handling change and the challenges that arise from change propagation are similar regardless of the cause of the change or the phase of the design project[START_REF] Eckert | Change and customisation in complex engineering domains[END_REF]. The impact of changes is not limited to the product itself, but can affect the rest of the organisation through shared resources and interlinked processes[START_REF] Ariyo | Unpleasant surprises in the design of complex products: why do changes propagate?[END_REF][START_REF] Shankar | Reasons for change propagation: a case study in an automotive OEM[END_REF]. Change is difficult to predict, because it is inherently not deterministic, and involves people making decision about how to respond to the need for change[START_REF] Earl | Predictability of Change in Engineering: a Complexity View[END_REF]. Various tools have been developed to assist predicting the impact of change, through anticipating changes(Cohan et al. 2000), probabilistic links[START_REF] Clarkson | Predicting Change Propagation in Complex Design[END_REF] and network analysis[START_REF] Pasqual | Multilayer Network Model for Analysis and Management of Change Propagation[END_REF].

Figure 2 :

 2 Figure 2: Parameter links between components

Figure 3 :

 3 Figure 3: Requirements, margins and constraints.

Figure 4 :

 4 Figure 4: Trade-offs among form, function and material.


Garry Miller
email: g.miller@auckland.ac.nz

Shubham Sharma

Claire Donald

Robert Amor

Developing a Building Information Modelling Educational Framework for the Tertiary Sector in New Zealand

Keywords: Building Information Modelling, Tertiary Education, Framework

Whilst Building Information Modelling (BIM) is rapidly being acknowledged as a driver for change in the Architectural, Engineering and Construction sector across the globe, the introduction of BIM into graduate and postgraduate teaching programmes in the tertiary sector in New Zealand has been minimal to date. New Zealand has an advanced albeit small economy, and whilst BIM is being deployed increasingly with effect in industry, there is no national BIM education framework and only one tertiary sector institution offers any BIM teaching in New Zealand (NZ). This paper reviews the current approaches to incorporating BIM into degree and certificate programmes in 25 leading international universities, pedagogical approaches and BIM critical success factors. A draft of a BIM educational framework for NZ is proposed based on this review. An approach for further design, development and deployment of the framework is also offered. This paper is intended to initiate debate and to start to build consensus between the academic community and industry on a national BIM educational framework for New Zealand.

Introduction

Building Information Modelling (BIM) is "a digital representation of physical and functional characteristics of a facility. A building information model is a shared knowledge resource of information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition" (National Institute of Building Sciences, 2007). BIM is being advocated by many as a catalyst for change, poised to reduce the industry's fragmentation and increase its efficiency by improving the communication between project teams [START_REF] Succar | Building information modelling framework: A research and delivery foundation for industry stakeholders[END_REF].

BIM has been identified by the New Zealand Productivity Partnership (a partnership established between government and industry) as a new technology which integrates data and knowledge management to minimize inefficiencies and enhance the value delivered during design, build and operation [START_REF] Kane | Productivity Roadmap. Building and Construction Sector Productivity Partnership[END_REF]. Implementation of BIM in NZ is one of four major work-streams in the Productivity Partnership's programme to deliver a productivity improvement of 20% by 2020.

There are some early adopters of BIM in New Zealand (NZ). There is evidence that some organisations are already deriving benefits from using BIM including improved project design, co-ordination, planning, project delivery and bottom line performance improvements [START_REF] Huber | New Zealand National BIM Survey[END_REF]. However, from anecdotal evidence it would appear that organisations doing so are the larger companies with international operations, who are able to gain benefits by transferring knowledge from overseas. As such, whilst BIM has the potential to significantly improve performance of organisations, in NZ it is not widely understood nor harnessed by New Zealand industry generally. A concurrent issue is also an almost complete lack of BIM educational provision by the NZ tertiary sector institutions, which exacerbates the slow adoption of BIM. Therefore is a need in New Zealand to develop an educational framework for the tertiary sector in order to enhance knowledge and skills in the local context.

To address this challenge the University of Auckland has developed a collaborative research and educational programme for BIM issues related to the Architectural, Engineering and Construction (AEC) sector in NZ. This programme is a collaboration between several parties, including other tertiary sector organisations and industry. This paper offers a draft educational framework to initiate debate and to start to build consensus in the academic community on a national BIM educational framework for New Zealand.

Literature Review: Background and Contemporary Issues for New Zealand

Despite the recent global interest in BIM it is in actual fact an old idea, with origins in the 1970's (Eastman et al., 2008). It has taken almost 40 years to become the commercially attractive tool that is so widely praised today [START_REF] Bernstein | Integrated Practice: It's not just about the technology[END_REF]. Perhaps the best evidence of its potential to add value to the construction industry is its widespread uptake by countries such as (but not limited to) the United States, United Kingdom, Denmark, the Netherlands, Finland, and Australia. However, in New Zealand a recent survey found that of 417 respondents, 10% do not understand what BIM is, 60% have some understanding, a further 20% have a reasonable appreciation of BIM's potential and only a final 10% have a clear appreciation of the advantages of BIM [START_REF] Huber | New Zealand National BIM Survey[END_REF]. As such BIM is still at the development stage of the typical product life cycle in the context of NZ. [START_REF] Tran | Shaving BIM: Establishing a Framework for Future BIM Research in New Zealand[END_REF] make a case for establishing a BIM research framework in NZ, and identify three reasons why BIM has not been widely used namely: slow uptake by companies; a lack of NZ-focused initiatives; and a lack of BIM-based building life cycle considerations. Of these three reasons the first appears to be a circular argument. The second reason is well made, and despite interest in BIM from policy makers, it would appear that there is no real appetite by political leaders to drive BIM implementation at a policy level. The third reason would appear to have some validity, but is not unique to New Zealand.

Other specific issues relating to the NZ context are the structure of NZ industry, the Canterbury post earthquake re-build, NZ regulatory issues relating to consenting processes, and the educational provisions in BIM. We discuss the structural issues and the educational provisions in more detail in the following sections.

Issues relating to BIM adoption by small to medium sized enterprises (SMEs) are particularly relevant for New Zealand. SMEs are defined in NZ as businesses that employ fewer than 20 full-time staff. More than 96% of businesses in the AEC sector are in this category (MED, 2011). Access to new technology, performance improvement approaches and training is often limited for SMEs by the lack of awareness of innovative processes, technologies and practices. This is primarily due to the costs of acquisition of new technologies and of training (Eastman and Sacks, 2008).

Furthermore, evidence is evolving from overseas that adoption of BIM models and processes by SMEs can represent a strategic driver for the performance improvement within the SME section of the AEC industry [START_REF] Gledson | Does Size Matter? Experiences and Perspectives of BIM Implementation From Large and Sme Construction Contractors[END_REF][START_REF] Sebastian | BIM application for integrated design and engineering in small-scale housing development: a pilot project in The Netherlands[END_REF]. When there are early adopters within the SME community, their example helps leverage on-going introduction of BIM across industry. [START_REF] Jayasena | Building Information Modelling for Sri Lankan Construction Industry[END_REF] and [START_REF] Wong | Building information modelling for tertiary construction education in Hong Kong[END_REF] emphasise that for BIM expansion, we need more BIM trained professionals in the AEC industry, and that such people are very hard to find because of insufficient BIM training and education. The essential training in this regard is needed for students in tertiary educational institutes. [START_REF] Gier | Does learning building information modeling improve the plan reading skills of construction management students[END_REF] carried out a research study in the USA to examine if BIM should be taught as a subject to construction management students. He conducted two questionnaire surveys targeted at general contractors and construction management programs. Based on the collected data, he concluded that construction management programs should teach BIM to their students.

In another study, [START_REF] Woo | BIM (Building Information Modeling) and Pedagogical Challenges[END_REF] pointed out that properly structured BIM courses would provide industry-required knowledge to prepare students for successful careers in the AEC industry. Instead of teaching a separate course, he suggested restructuring existing construction courses to integrate BIM into the course content.

Whilst these studies are informative, their paradigm is from the perspective of BIM rather than from the perspective of educational design. We therefore provide a brief overview of some of the literature on educational frameworks, together with a proposed development approach in a later section of this paper.

Developing the Draft Educational Framework

In developing a draft educational framework for BIM we have considered a number of factors, namely:

1. Contextual issues for New Zealand; 2. Critical success factors for BIM implementation from international literature; 3. Review of existing BIM educational programmes offered by leading international universities; 4. Pedagogical approaches to the design of educational frameworks. We have already provided an overview of context issues for New Zealand in the literature review, and the following sections of this paper consider the remaining factors before offering a draft framework.

BIM Critical Success Factors

Table 1 is a comparison of BIM success factors including enterprise resource planning, new product development and project management success factors from different authors, categorized into people, process, management and technology factors.

Table 1. BIM Critical Success Factors

By analyzing the table, it can be clearly seen that for process factors, most of the authors focus on a sound and clear objective or strategy by identifying the goals. On management factors, most of the authors recommend implementing in an integrated team-based approach while maintaining well-defined rules. For people factors, training and employee support as well as having the right expertise are identified as essential. Lastly, for technology factors, technical support, efficient hardware and software, sufficient resource allocation and standard equipment are considered critical factors. We believe these success factors are informative for design of a BIM educational approach.

Review of BIM Educational Programmes

We reviewed the current BIM educational programmes in the 25 leading international universities for engineering according to the Times Higher University Rankings (2012). We did keyword searches on the main website of the top 25 universities, and also specifically searched for "BIM Course Outline". The name of the BIM course, the subject level, duration of the course and teaching method were identified at both undergraduate and postgraduate levels. Also, the same approach was used to search for BIM courses for the eight universities in New Zealand in order to compare trends.

Out of all the top 25 universities in the world for engineering, 16 of them are currently teaching BIM courses as summarized in Figure 1.

Fig 1. BIM Education Provision in Leading Universities for Engineering

The duration of most of the courses in the universities is one semester, with 15 out of 16 having semester-long BIM courses. Also, the preferred level of teaching BIM courses is at undergraduate level, with 9 out of 16 universities teaching BIM courses at this level. Six out of 16 universities also have some BIM courses at Masters level, while only 3 universities have certificate level courses. A list of the universities and further details of their BIM course offerings are provided in the Appendix.

Of the 8 universities in New Zealand none currently have a taught course or progamme at Bachelor or Masters level in BIM. However, there is a good track record in BIM research in New Zealand, which positions universities in New Zealand well for developing research informed BIM educational programmes. Only Unitec Institute of Technology (a polytechnic) has BIM courses, which appear to be orientated towards skills development and vocational training. Therefore, there is currently a gap in the educational sector in New Zealand for providing university level education at Bachelor and taught Masters levels.

A pedagogical approach to the design of a BIM educational framework for NZ.

We propose that a starting point for designing a new educational framework for BIM in New Zealand is to conduct a comprehensive needs analysis according to the widely used ADDIE model (Analysis, Design, Development, Implementation, Evaluation) of instructional design [START_REF] Dick | The systematic design of instruction[END_REF]. This establishes the extent and nature of the demand in the various sectors of the BIM professional community, the requirements of key stakeholders, necessary educational, technical and funding resources as well as the characteristics of the potential students. The research reported in this paper provides the basis for such a needs analysis.

The results of the completed needs analysis will inform the design of the educational framework for BIM. During this second stage we will determine the goals and intended learning outcomes for the curriculum, its structure, and plan the teaching and assessment methods. An initial set of goals and outcomes are proposed later in this paper. The central question we address during this process is: what is most important for the students to know, to be able to do, and what are the best ways for them to learn this? [START_REF] Toohey | Designing Courses for Higher Education[END_REF].

Approaches to curriculum design at university tend to fall into five categories [START_REF] Toohey | Designing Courses for Higher Education[END_REF]: traditional, or discipline-based; performance-or systems-based; cognitive; personal relevance or experiential; and socially critical. These are not necessarily applied discretely. Indeed, we propose to combine elements from three of these categories to designing a national BIM framework: the traditional or disciplinebased approach, (the BIM educational framework will be divided into topics based on the important concepts); the performance or systems-based approach, (support particular teaching and learning methods according to clear and assessable objectives) and the cognitive approach (students will be helped to develop specific intellectual abilities and conceptual structures required for problem solving across multidisciplinary domains).

Crucial to devising a successful national BIM programme for tertiary students will be applying Biggs' strategy of constructive alignment [START_REF] Biggs | Enhancing teaching through constructive alignment[END_REF]. This involves aligning the intended learning outcomes, assessment methods and planned learning opportunities closely with one another. In addition, we will ensure that flexible elearning opportunities are incorporated appropriately, using an integrated e-learning framework which has been successfully applied in other degree programmes [START_REF] Blake | An Instructional Design Course for Clinical Educators: First Iteration Design Research Reflections[END_REF].

Currently underpinning our approach to this design are the theories of authentic learning and situated cognition [START_REF] Brown | Situated cognition and the culture of learning[END_REF]. These place primary importance on the real-life context of learning, suggesting that for learning to be effective and meaningful, it must occur in the same context in which it will be used and applied in the future, similar to apprenticeship training. In a tertiary education context, authentic learning environments include a number of key elements proposed by [START_REF] Herrington | A guide to authentic learning[END_REF], which we would aim to incorporate in a new curriculum for BIM. These include providing authentic learning activities, access to expert performances and modeling of processes, adopting multiple roles and perspectives, collaborative construction of knowledge, and authentic assessment of learning within the tasks.

We believe that this approach will provide the sound pedagogical basis required as we move forward with the planning and development of a new BIM framework for the tertiary education sector in NZ.

Proposed Draft Framework

In developing a proposed educational framework for BIM in the tertiary sector for New Zealand we identified disciplines (knowledge domains) and mapped them against the NZQF. One of the challenges of devising a BIM education programme is that BIM crosses a number of traditional disciplinary boundaries. BIM certainly crosses the architectural, engineering and construction domains, and the AEC industry is often defined as a sector. However BIM is also an approach that integrates technology and software development together with business, enterprise and management. We illustrate the relationship between these sectors in a Venn Diagram in Figure 2. In devising such an integrated approach across disciplines we seek to incorporate some of the BIM critical success factors identified earlier in this paper.

Figure 2: Venn Diagram Showing Discipline Relationships for BIM

We also believe that an educational framework should encompass three broad types of education: vocational training / continuing professional development, degree programmes (taught), and research (including PhD programmes). The requirements in each of these are different, and so the framework needs to be designed to serve the diverse educational needs of a broad spectrum of stakeholders. Our draft framework is presented in Figure 3.

In the architectural design representation, BIM enforces a migration from two to three dimensions by creating intelligent, multi-dimensional building models. Hence, in reality BIM goes beyond simply representing the geometry of a building. As such BIM is not just a new way of drafting and is not a technique that might be taught like technical drawing. Rather it is a more fundamental approach which needs to be studied and well understood. BIM views can show and intelligently interpret the types of materials and construction details including scheduling of building elements for assembly. Through this capability BIM provides an opportunity for various users with different backgrounds to work collaboratively across traditional disciplines.

One of the debates in BIM education is the question of whether BIM should be integrated into existing curricula of architecture and engineering degrees (i.e. by integrating BIM into teaching on existing papers), or whether it should be taught as a specific topic in its own right. We take a pragmatic view that it probably needs to be a combination of both, with an incremental, organic integration into existing Bachelor level degrees probably being the more acceptable and sustainable approach. However incremental change in tertiary sector can be slow, and there is an argument to be made for an integrated degree targeted at mature students who have gained some industry experience and are seeking to gain specialized knowledge and skills in BIM. Hence we also propose an integrated postgraduate course delivered as a taught masters degree. Such a degree should cross the boundaries of traditional disciplines, and ideally should be a collaboration between faculties and even between different universities. Whilst such collaborations can be difficult to achieve in practice they are not impossible, and given that BIM typically facilitates collaboration in industry, we argue that it should do so in academia also. Development of a specialist taught Masters programme provides a possible avenue for collaboration.

Figure 3: Draft BIM Educational Framework for New Zealand

While it is premature to define the content of the educational programmes, goals should be identified. We have attempted to draft a set of goals and intended learning outcomes to stimulate debate. These are presented in Table 2: In order to measure the success of achieving the BIM educational goals we plan to implement a longitudinal study to gather data on learning outcomes and uptake of graduates being offered employment in industry in BIM related roles. In order to broaden the relevance of this research to the international community we are seeking collaborations to benchmark outcomes with the tertiary sector in other parts of the world.

Future Work

We outlined our planned pedagogical approach to the design of an educational framework in a previous section. To facilitate the of the framework we will seek to establish collaboration with the other tertiary institutes in New Zealand, industry and other interested stakeholders such as professional bodies, trade associations, the Productivity Partnership, Building Research Association of New Zealand and the Ministry of Business, Innovation and Employment. There is a range of practical mechanisms we will seek to introduce including formation of an advisory group, and establishment of a funded BIM research and educational programme. An injection of funding from the public sector is needed to kick-start such a programme, as industry-led funding is unlikely to be forthcoming due to the early stage in the technology life-cycle and fragmented nature of industry in the AEC sector. An important future stage will be to derive the intended learning outcomes and align them with appropriate assessment strategies. Further research is needed to develop (or redraft as appropriate) the learning outcomes proposed in this paper. Such research must seek to identify the particular needs of SME's. The formulation of intended learning outcomes in partnership with industry will help to ensure the educational framework meets the needs of NZ industry.

Conclusions

We have argued that New Zealand AEC sector is at the early development stage of BIM life-cycle, and that whilst the potential of BIM is generally recognised there are barriers to wider implementation of BIM, particularly the structure of NZ industry and the lack of BIM educational provision. Whilst the international tertiary sector has already established BIM educational courses and programmes, there is an almost complete lack of BIM educational provision at undergraduate and taught postgraduate levels in New Zealand: a deficiency that must be tackled. As a first stage in addressing this issue we have offered a draft educational framework for NZ, which seeks to incorporate disciplines across traditional boundaries, that is based on wellfounded pedagogical principles, acknowledges BIM critical success factors, is informed by overseas programmes, and focused on learning outcomes. This framework is offered to initiate debate and to start to build consensus between the academic community and industry on a national BIM educational framework for New Zealand.

Table 2 : Suggested Goals for New Zealand BIM Education Framework

 2

	Element of	Goals
	Framework
	National BIM	1. The framework is accepted by all tertiary sector organisations in NZ;
	Educational	2. Universities and other tertiary sector education providers collaborate
	Framework	on teaching and research;
		3. The New Zealand BIM educational framework is acknowledged as
		being world class in international comparators;
		4. The BIM educational programme leads NZ industry towards the
		mature phase of the BIM technology lifecycle.
	BIM research	1. A dynamic programme of research, extending knowledge at the most
		advanced level;
		2. Research supported and funded by industry and public sector
		working in partnership with the tertiary sector;
		3. Some commercialization of the best research outputs
	BIM taught	Students completing the degree:
	Masters degree	1. Have advanced understanding of underpinning key principles of
		BIM, with an ability to discern what BIM can and cannot do;
		2. Are able to create and manage 3D models, and some of the extension
		applications into 4D, 5D etc.;
		3. Have the knowledge and skills in a range of topics including (but not
		limited to): collaboration, BIM procurement issues, management of
		technology, business performance improvement, software
		development, database systems etc.;
		4. Are able to undertake research on at least one specialized topic
		relating to BIM;
		5. Are able to use a variety of BIM software;
		6. Are able to introduce BIM into their employer organisations;
		7. Are able to use BIM effectively in a range of design and /or
		construction scenarios.
	Existing bachelor	BIM is integrated into the existing curricula in Architecture and
	degree	Engineering degree programmes:
	programmes in	1. Graduates have a sound understanding of underpinning key
	AEC sector	principles of BIM;
		2. Understanding of 3D modeling techniques and ability to manipulate
		3D models;
		3. Appreciation of the wide range of benefits derived from BIM
		4. Able to use a variety of BIM software;
		5. Able to use BIM effectively in a range of design and /or construction
		scenarios.
	Vocational	1. An active and dynamic programme of vocational training and CPD to
	training and CPD	meet the training needs of industry;
	education	2. Accessible and affordable training for a diverse New Zealand sector
		with significant portion of SMEs;
		3. Awareness and knowledge at all levels of industry of benefits of
		BIM.

Appendix


Vishal Singh
email: vishal.singh@aalto.fi

Challenges for integrated design and delivery teams in AEC

Keywords: BIM, teamwork, mental models, integrated design and delivery solutions

This paper discusses the critical factors for managing teams for integrated design and delivery solutions (IDDS), which aims to involve BIM tools, processes and skills across different stakeholders such as architects, consultants, contractors, and suppliers through the project lifecycle. Since IDDS is a recent development, the associated teamwork factors and challenges in implementation are not currently well understood. This paper reports the findings from a research that investigates this gap and forms the basis for future research directions. The findings reported in this paper are based on focus group interviews with representatives from leading organizations in the Australian and Finnish construction sector. The critical factors for an IDDS team are examined and discussed using the construct of mental models. In particular, this research investigates the critical task, process, context, and competence factors specific to the IDDS teams.

Introduction

The lack of integrated design and delivery across the lifecycle of multi-organizational construction projects and inefficient manpower management through the project lifecycle costs billions of dollars in waste [START_REF]Construction Forecasting[END_REF]. As a result, there is a greater push for new ways of working that promote collaboration and integration across the project partners through the different phases of the project lifecycle. Accordingly, approaches such as Integrated Design Delivery Solutions (IDDS) and Integrated Project Delivery (IPD) are being developed, with greater emphasis on creating more productive environments through concurrent engineering [START_REF] Love | Concurrent engineering: a strategy for procuring construction projects[END_REF], enabled by information systems, technology mediated practices, and collaborative work environments [START_REF] Cib | CIB White Paper on IDDS "Integrated Design and Delivery Solutions[END_REF][START_REF]Integrated Project Delivery: A Guide[END_REF]. This trend is based on the rationale that effective service integration and collaboration can reduce inefficiencies and waste, through reduced duplicity and rework [START_REF] King | Service integration and co-ordination: A framework of approaches for the delivery of co-ordinated care to children with disabilities and their families[END_REF][START_REF] Moore | Integrated project teams' performance in managing unexpected change events[END_REF].

Nonetheless, full service and process integration is challenging and requires effective change management strategies [START_REF] Orlikowski | An Improvisational Model of Change Management: The Case of Groupware Technologies[END_REF][START_REF] Nah | Critical factors for successful implementation of enterprise systems[END_REF] and people engagement processes [START_REF] Glendinning | Breaking down barriers: Integrating health and care services for older people in England[END_REF]. Hence, the change towards integrated design and delivery within the architecture, engineering and construction (AEC) sector is contingent on sound understanding of the teamwork and engagement processes.

In the AEC sector, design integration requires a multiplicity of skills, knowledge and experience. Design practice requires management tools and skills besides the design skills and the domain knowledge. The performance of the collaborative design team not only depends on how the individual members perform the tasks related to their roles but also on how effectively they coordinate their tasks, roles and responsibilities with the other members of the team [START_REF] Love | Concurrent engineering: a strategy for procuring construction projects[END_REF]. For collaborative teams to be efficient, team members need well developed mental models of each other and that of the task, process, context and competence of the team [START_REF] Badke-Schaub | Mental models in design teams: a valid approach to performance in design collaboration?[END_REF][START_REF] Klimoski | Team Mental Model: Construct or Metaphor[END_REF][START_REF] Langan-Fox | Mental models, team mental models, and performance: Process, development, and future directions[END_REF][START_REF] Lim | Team mental models and team performance: A field study of the effects of team mental model similarity and accuracy[END_REF]. Well-developed mental models of the team members can significantly improve the cost, schedule, and quality measures, especially in complex projects [START_REF] Rouse | The role of mental models in team performance in complex systems, Systems, Man and Cybernetics[END_REF], which is often the case with construction projects. Managing integrated construction project teams further increases the complexity as the team is expected to work concurrently across the project lifecycle. However, there is little research and understanding of the teamwork management issues within such teams, especially there is little structured breakdown of issues according to the task, process, context, competence and team factors that constitute the mental models of the members of the multi-organizational construction projects.

This paper reports on the findings from a research study aimed at identifying the critical factors affecting the formation of mental models in multi-organizational construction projects, especially in view of the IDDS objectives. In particular, we investigate the critical task, process, context and competence factors specific to the integrated design and delivery teams.

The reported findings are based on focus group interviews (FGIs) and face-to-face (FFs) interviews with representatives from Australian and Finnish AEC sector on the potential challenges to integrated design delivery practice using a collaboration platform, with Building Information Model (BIM) at the core of data exchange.

Background

The construction sector is known to be a slow adopter of management and technical capabilities that other industries such as manufacturing are able to integrate earlier in their practice. Among others, the structural organization of the construction sector, which is markedly different to that of the manufacturing sector, is mooted as an important factor [START_REF] Anumba | Organizational structures to support concurrent engineering in construction[END_REF]. As a result, integration of key players is considered to be important for project success. As each player pursues its own contractual objectives, it is suspected that a lack of integration and teamwork has resulted in low productivity and low innovation. Such challenges are likely to impede the IDDS initiatives envisioned by the construction industry as the design and delivery practice of the future. One of the biggest challenges for managers and organizations involved in the multi-organizational design and construction projects is to understand, and deal with, a distributed project team with diverse task, process, context, and team member mental models, resulting from the diversity in social, operational and functional backgrounds of the team members at individual as well as organizational level.

Formation of mental models has been studied across diverse domains [START_REF] Badke-Schaub | Mental models in design teams: a valid approach to performance in design collaboration?[END_REF][START_REF] Mohammed | Team Mental Models in a Team Knowledge Framework: Expanding Theory and Measurement across Disciplinary Boundaries[END_REF]. It is well established that effective teamwork requires various kinds of competencies that can be discussed in terms of the knowledge, skills and attitudes that are specific or generic to the task, and the team [START_REF] Ancona | Improving the Performance of New Product Teams[END_REF][START_REF] Cannon-Bowers | Teamwork competencies, The interaction of team member knowledge skills and attitudes[END_REF][START_REF] Cohen | What Makes Teams Work: Group Effectiveness Research from the Shop Floor to the Executive Suite[END_REF]. Mental models for the task, process, context, competence and the team members are critical to effective team performance [START_REF] Badke-Schaub | Mental models in design teams: a valid approach to performance in design collaboration?[END_REF][START_REF] Klimoski | Team Mental Model: Construct or Metaphor[END_REF][START_REF] Langan-Fox | Mental models, team mental models, and performance: Process, development, and future directions[END_REF][START_REF] Lim | Team mental models and team performance: A field study of the effects of team mental model similarity and accuracy[END_REF]. These findings suggest that organizational contingency theories [START_REF] Donaldson | The Contingency Theory of Organizations[END_REF] also apply to formation of mental models in teams. That is, the critical parameters associated with the different mental models and their values may be specific to the project, despite generic patterns across an industry. Therefore, specific parameters and their values need to be mapped for each project, Table1. Understanding the likely effects of pre-developed mental models of team members, based on their prior experience, and the impending project requirements, can improve project decision making. Such approaches have been used to form effective small project teams, where the scale of the project and the personnel data is manageable using a manual process. For example, [START_REF] Wilde | The Construction and Organization of Effective Teams[END_REF] reports the use of psychometric data to consistently form high performing student design teams. However, in real world construction projects, the complexity, the number of variables, and the amount of data to analyze can be expected to be much higher. This means such approaches towards creating high performance teams cannot be adopted unless decision support systems are developed to record, manage and simulate large data sets.

This research is part of a research initiative that aims to address some of the related issues. The critical factors pertaining to teamwork in IDDS projects identified in this research will contribute towards the development of such a decision support system (DSS). The planned agent-based DSS will build on the prior research on computational modeling of project teams [START_REF] Kunz | The Virtual Design Team: A Computational Simulation Model of Project Organizations[END_REF][START_REF] Singh | Computational Exploration of Modes of Social Learning and Team Mental Models[END_REF].

Research data collection and analysis

The findings reported in this paper are based on data from FGIs and FFs conducted with representatives from various stakeholder groups that typically form an IDDS team. Three FGIs were conducted in two major cities in Australia and included architects, engineers, consultants, contractors, facility managers and construction project collaboration platform service providers. Representatives from large contracting firms and government organizations, who often work as clients in construction projects also participated in the workshop. The FGI discussions revolved around the potential challenges to integrated design delivery practice using a collaboration platform, with BIM at the core of data exchange. The FGI participants were encouraged to discuss the challenges to using an integrated information system and Building Information Models for managing the information supply chain across the project lifecycle. The FGI data was complemented by twelve FFs, two in Australia and ten in Finland. The FGIs and FFs were recorded on tape and transcribed for analysis to categorize the discussions across the issues relating to task, process, context, competence and team member mental models.

Verbal protocol analysis technique was used to analyze the Australian data and identify the underlying patterns and trends across the identified themes, i.e., task, process, context, competence and team. Table 2 provides sample segments to exemplify the classification and the coding scheme. "Protocol analysis is a rigorous methodology for eliciting verbal reports of thought sequences as a valid source of data on thinking" [START_REF] Ericsson | Protocol analysis in psychology[END_REF].

Preliminary analysis of part of the Finnish data has been conducted, and verbal protocol analysis of the Finnish data is yet to be conducted.

Research findings

Figure 1 shows the discussion pattern in the FGIs, based on the verbal protocol analysis results. As plotted in Figure1, though the data indicate a fairly uniform distribution of issues and concerns associated with the different mental models, i.e, task, process, context, competence and team members, the apprehensions around processes, including work and business processes is relatively higher. The open ended discussions primarily revolved around the challenges in developing and using an integrated Building Information Model in a project, and the issues with managing the information. Discussions indicate that even at the outset of a project the different stakeholders are likely to start with conflicting mental models and apprehensions about each other's beliefs and level of engagement in the project. Following are some of the key factors associated with the task, process, context, and competence and team member mental models:

Task mental model

The integrated project team is expected to collectively work together in providing timely information, feedback and data through a collaborative platform to create a detailed BIM for the project, which many interviewees considered as central to the task definition in an IDDS project. Following are the critical task mental model related factor:

Purpose and scope of the model: Team members need a shared understanding of the purpose of BIM in the project. In some projects it might be desirable to create and use a BIM model across the entire project lifecycle while in other cases such models may only be developed for specific purposes such as simulating and planning constructability.

Level of detail: Team members need some clarity on questions such as: How much detail is needed in the model? Which parts of the model need more details or do all parts of the model need the same level of details? How are the details at different levels of abstraction, and across the different phases of the project, to be linked and managed? Level of detail in the model is contingent on the project requirements and the purpose of the model. Clarity on the level of detail is important to determine work breakdown and planning.

Structure of the model:

The use of BIM and the task typically requires decomposition and integration of the task. That is, model development is a multi-user activity, which means the team members need to coordinate the model development activities. Hence, the team members need to understand the task breakdown structure, and how the task is shared and distributed across the team.

Purpose and the level of the model needs to be clearly stated upfront as part of the contractual agreements. Findings indicate that the different project partners may have different expectations from the purpose as well as the level of detail desired in a BIM model. For example, designers, contractors and facility managers (FM) each view the purpose of the BIM model differently, and to each of these actors, the primary role of BIM is associated with their discipline. As such, each of these models such as the design model, construction model and FM model require different types, and different levels, of details. Therefore, an initial plan is needed on how these different models can be achieved through minimal rework and duplication, and maximum reuse.

Related aspects of task or model development where shared understanding is needed include model types and sub-models, accuracy and completeness, as-built data for facilities management, and documentation and communication tasks.

Process mental model

The Participants identified various aspects of the collaborative process that need discussion and clarity among team members and collaborators for effective management of an integrated BIM project development. This includes agreed protocols and practices for business processes, collaboration and information exchange, and interaction with the model. Mutual agreement and processes are critical for the following:

Business processes: IDDS and IPD approaches are yet to be embraced in the construction industry and the lack of precedence and familiarity leaves apprehensions about business models and transactions. Among other concerns, FGI participants were unclear about the fee structures in the resulting re-configured work-load distribution and information supply chain; data transfer and ownership; and liabilities and legal implications. Participants also discussed potential role for BIM service providers, model managers, application vendors, cloud computing and software licensing models, highlighting related concerns over lack of experience if any of these are to be involved in an impending construction project.

Design review and clash detection: Participants acknowledged the need for agreed protocols to conduct design review using BIM models and capabilities such as clash detection. Participants reported resistance among some stakeholder groups to change design review norms that still follow traditional methods. Discussions reflect increased confidence in collocated workplaces for multi-disciplinary integration and conflict resolution such as 'Big Room' concepts.

Version management: Discussions reveal concern towards potential conflicts that may arise from multiple files and versions of the model generated across the team and the design development phases, besides the concerns towards software versions.

Data organization and management: Data explosion and information overload emerged as a common concern across many participants. The need for archiving, history traceability, and data security were emphasized. Hence, a shared understanding of data management processes is needed.

Context mental model

Context refers to the team situation and scenarios. The discussions about the context revolved around the team's culture and practices, and what the FGI participants thought determines a team's response to known and known scenarios, including changes in tasks, processes and so on. Following were identified as the critical factors associated with context mental models:

Work culture and practice: Adopting IDDS approach will require adopting new work culture and news ways of working, and shifting organizational cultures towards an integrated service system.

Project phase: Team members need to have clear understanding of their roles, responsibilities and contributions to the integrated BIM model at different phases of the project. This includes clarity on the scope of the model and its usage across the different phases of the project.

Regulations and standards: Building regulations and standards vary across the different geographical regions, which needs alertness and clarifications, especially when working on projects or teams distributed across geographical boundaries.

Project requirements: Team members need a shared understanding of the project requirements and the scope and level of integrated design delivery applicable to a given project. Discussions indicate the need for critical assessment of the project requirements at the outset of the project. For example, does the scale of the project justify how the team is organized for integrated design and delivery? How to monitor and measure the progress of the project? How should the team respond to the emergent and unforeseen project requirements, and what does it mean for the IDDS practice?

Competence mental model

Competence refers to the team's capabilities, which is either augmented or constrained by technology, which is once again related to the level of technology integration and technical competence of the team. With respect to BIM based collaboration for IDDS, competence appeared frequently in the discussions, often tied closely with team member mental models, i.e. perception of the competence of the other collaborators.

Competence of project partners and their tools: Project managers need to map the available resources and capabilities distributed across the people and tools to identify potential clashes and lack of compatibility. For example, the team may have the right tools but they may not have competent or skilled users. Teams may have competent users but they may not have the right tools. Or, teams may have competent users as well as competent tools, but the chosen tools may not necessarily be compatible, reducing the overall competence. At the same time, team members not only need to know about their competencies but they also need to know their limitations, and that of the tools being used. Issues of data format and import/ export capabilities of the software need to considered at the project planning stage itself. FGI participants also raised concerns over the other capabilities of the information systems that include security; bandwidth; server capacity; visualization capabilities; integration capabilities; querying and archiving; usability and interface.

Capabilities to learn and train during the projects: How the team is organized and what knowledge management practices the team adopts, including how they use collaboration platforms and information systems, will determine how much the team members can learn during the project. Efficient teams can build on the opportunity for social learning and team building to increase competence during the project.

Team member mental model

Team member mental model refers to team members' beliefs about each other, which determines how the team members interact and communicate with each other, and how they collaborate and work as a group. FGI discussions revealed a concern among the participants over the general tendency of functional groups and disciplines to work in isolation. Lack of trust in accuracy and completeness of the information and models created by members of other disciplines was a concern.

Discussions emphasized that roles and responsibilities need to be clearly defined, and the implications for the changing roles and responsibilities in the changing work environment needs to be communicated. Participants reported lack of clarity with changing roles and responsibilities across various dimensions such as, does the new role require new skills, or, do the changing roles and responsibilities restructure the actor network and the social ties? The discussions indicated that, in general, the team members seek answers to one common question: what is in there for me, and why should I change? That is, team members consider the effort towards the changing roles and responsibilities as an investment that must be rewarding, and there must be a return on investment. Some of the questions that individuals and firms in multiorganizational collaboration consider as part of their assessment of the return on investment include: Is it worth investing in a new technology unless the returns from the project or the alliance cover it? Is the project valuable enough to invest resources in adopting and learning new ways of working?

The task, process, context, competence and team member mental models are found to be closely interrelated, with the different issues overlapping across different mental models. For example, skills acquisition is not only about the competence but also about what the individuals think of the team, and their roles and responsibilities towards the team. Further research is needed to build on this mapping and develop a framework than can be used for computational application.

Conclusion

This research adopts the construct of mental models as the basis for establishing the parameters of team work, especially in context of integrated design and delivery teams in multi-organizational construction projects. Findings from the focus group interviews and face to face interviews with representatives of various stakeholder groups are analysed and categorised into issues related to task, process, context, competence and team member mental models. The empirical data suggests that there are overlaps across the different mental models and the key issues concerning efficient teamwork and project management. Among other issues it is evident that team members have a sense of measuring their investment in the project and the returns on the investment. This investment involves multiple parameters such as time, effort, money, and reputation. Further research is planned to investigate these issues and develop the framework. In particular, the primary question raised for further investigation is: what is the threshold point beyond which the critical factors combine such that investment in BIM technologies, tools, processes and skills is perceived justifiable by the different stakeholders?

Fig. 1 .

 1 Fig.1. Discussion pattern in FGIs reflected by % of segments dedicated to each theme (sum is greater than 100% as many issues concerned more than one theme)