Karoliina Parhiala
email: karoliina.parhiala@aalto.fi

Mehmet Yalcinkaya
email: mehmet.yalcinkaya@aalto.fi

Vishal Singh
email: vishal.singh@aalto.fi

MAINTENANCE OF FACILITIES AND AIRCRAFTS: A COMPARISON OF IT-DRIVEN SOLUTIONS

Keywords: Building Information Modeling, BIM, Digital Mockup, DMU, Configured Digital Mockup, cDMU, Maintenance

Building Information Modeling (BIM) can significantly impact both new as well as existing architecture/engineering/construction (AEC) projects. It can provide a virtually simulated and large integrated database that can be leveraged not only in design and engineering, but also in planning and management operations, and facilities maintenance. Although most of the BIM tools are now mature enough to use in various phases of project lifecycle, they have been primitive and under-developed for many years. The concepts underpinning BIM have been around since the 1960s through various manufacturing industries such as automotive, ship building or aerospace. In the aerospace industry, especially in aircraft design and manufacturing, the concept similar to BIM is a Digital Mock-Up (DMU). It is both a tool and a product of engineering. As in BIM, aircraft's DMU is also a comprehensive digital product representation that is used to simulate the use, behavior and performance of a finished aircraft. While BIM and DMU are used for different industries and products, they do share similarities and differences. This paper briefly describes BIM and DMU technologies and their context, specifically focusing on implementation of these two technologies for operation and maintenance (O&M).

Introduction

From the phases of the lifecycle of any type of manufacturing project, the operations and maintenance (O&M) phase is the longest one and is expected to cover previous costs of its lifecycle phases and to produce profits for its owner. O&M can be defined as "all actions that have the objective of retaining or restoring an item in or to a state in which it can perform its required function to ensure related business operations are efficient in terms of using the optimum resource as needed, and meeting customer requirements. These actions include the combination of all technical and corresponding administrative, managerial and supervision activities" [1]. O&M services include different activities with respect to the nature of the related industry. The critical aspect to achieve the objectives of O&M services is information management and application of state-of-art technologies to the related industry. This paper presents two state-of-art IT-driven approaches towards product lifecycle management (PLM); Building Information Modeling (BIM), specifically developed for architectural/engineering/construction (AEC) and Digital Mock-Up (DMU) applied in mechanical engineering, especially in aviation industry. The paper describes BIM and DMU technologies and presents logical and functional similarities between them in product development and finally focuses on implementation of these two systems for O&M phase of the associated products' lifecycle.

IT-Driven Solutions for PLM: DMU and BIM a. Digital Mockup (DMU)

Digital Mock-Up is a terminology used for 3D representation of a product. It is composed of 3D Models, Computer Aided Design (CAD) native files and/or visualization data, and Configuration Metadata. The metadata is Product Structure with parent-child relations and positioning information, and Attributes for lifecycle management. Attributes are all the business and technical information of the product. This means that besides including the data of products' parts, it holds information at least on work sharing, industrial flow, regulations of authorities, change process and configuration management. DMU is more than a CAD file. DMU integrates data from engineering, manufacturing and maintenance, and uses the data to simulate various industrial processes, uses, behavior and performance of the finished product [START_REF] Dolezal | Success Factors for Digital Mock-ups (DMU) in complex Aerospace Product Development[END_REF].

Barring a few exceptions, e.g. [START_REF] Dolezal | Success Factors for Digital Mock-ups (DMU) in complex Aerospace Product Development[END_REF], there are limited academic studies on DMU, and nearly all of the knowledge on DMU comes from aviation industry. Most outspoken on using DMU in their product development process has been the aircraft manufacturer Airbus S.A.S [START_REF] Airbus | Setting new standards with the A350 XWB Digital Mock-Up[END_REF]. Therefore, the concept of DMU is presented through an example of DMU at Airbus. For Airbus, DMU is the source of all the original product information and the binding reference in all Airbus's operations. But first of all, it was created to service the design and engineering processes. Everybody, inside and outside Airbus, subcontractors and suppliers are expected to work with the same DMU, from the same, shared database and access the latest information possible [START_REF] Parhiala | M Utilising Configured Digital Mock-Up in Aircraft Continuing Airworthiness Management[END_REF]. DMU at Airbus is presented in figure 1. The DMU can be accessed through several different views. This way, the user can not only access the data that is relevant to his/her work, but the connection of the data still remains within the product structure. [START_REF] Garbade | DMU@ Airbus-Evolution of the Digital Mock-up (DMU) at Airbus to the Centre of Aircraft Development[END_REF] Different views are represented in Figure 2. DMU starts at the design phase from where on, the whole lifecycle of the aircraft can be envisioned [START_REF] Garbade | DMU@ Airbus-Evolution of the Digital Mock-up (DMU) at Airbus to the Centre of Aircraft Development[END_REF]. It is used for aircraft representation, assist the communication and decision making throughout whole lifecycle of the aircraft. With the DMU, different kinds of scenarios to visualize and test various design solutions, for example cockpit ergonomics, are created. For aircraft performance and structural analysis, the DMU provides behavior simulations already in the early stages of the development. To reduce physical prototypes to minimum, the DMU is utilized to simulate and optimize the work in manufacturing factories, validate the transport concept and plan the final assembly line. [START_REF] Parhiala | M Utilising Configured Digital Mock-Up in Aircraft Continuing Airworthiness Management[END_REF] Figure 1. Definition of the Configured Digital Mock-Up at Airbus [START_REF] Parhiala | M Utilising Configured Digital Mock-Up in Aircraft Continuing Airworthiness Management[END_REF] Figure 2. Different disciplines extract their views from the Aircraft [START_REF] Airbus | Setting new standards with the A350 XWB Digital Mock-Up[END_REF] For each product configuration, hence each aircraft configuration, the DMU is called Configured Digital Mock-Up (cDMU). As customers are usually ordering more than one aircraft with the same configuration, the first configured and manufactured aircraft of the order is called Head of Version (HoV). Aircraft manufactured later with the same configuration are copies of the HoV. The cDMU is designed only for HoV, but then copied and linked to all aircrafts with the same configuration. As a result every manufactured aircraft has its own cDMU [START_REF] Parhiala | M Utilising Configured Digital Mock-Up in Aircraft Continuing Airworthiness Management[END_REF].

b. Building Information Modeling (BIM)

BIM represents both the technology as well as the process of digital representation of a facility through the use of object-oriented, data-rich, models potentially across the planning, design, construction and operation phases of the facility. In that sense, unlike DMU with its clear meaning, the terminology BIM is interchangeably used to represent the digital model (Building Information Model), the process (Building Information Modelling), and increasingly the approach to managing the technology and the process (Building Information Management). Nonetheless, the BIM model can be viewed, extracted and analyzed by different stakeholders and user groups to manage, simulate and analyze various aspects of the project for improved decision making, operations and maintenance of the facility [START_REF]The Contractor's Guide to BIM[END_REF][START_REF] Mitchell | Adopting BIM for facilities management: Solutions for managing the Sydney Opera House[END_REF].

BIM is also composed of 3D Models, native CAD files and/or visualization data, and Configuration Metadata. The metadata is Product Structure with parent-child relations, and Attributes that are the main identifiers for model management such as object types, ownership and history. BIM also allows additional Attributes to be added, which can include information about the business and technical information of the objects. This means that besides including the geometry and specifications of the objects in the model, it is possible to add information that can be intelligently used for workflow management, procurement and regulations by defining relationships between such attributes. However, unlike DMU such attributes and information on work sharing, industrial flow, regulations of authorities, change process and configuration management are rarely included in current BIM models. Thus, BIM can be configured and modified regarding the project/task requirements with the potential support of external software and hardware. Similar to DMU, BIM is expected to be the source of all the project information linked through a shared database. It is expected that in an ideal BIM project the different stakeholders such as the designers, client, contractors, subcontractors and suppliers can work with a shared BIM and access the latest information [START_REF] Gu | BIM : Expectations and a reality check[END_REF]. The use of a shared database in BIM can ensure that the different model views and data can be checked and updated for consistency and conflict resolution [START_REF] Singh | A theoretical framework of a BIM-based multi-disciplinary collaboration platform[END_REF].The model can be used to demonstrate the entire building lifecycle from conceptual design to demolition (Figure 3) [START_REF] Dispenza | The daily life of building information modeling (BIM)[END_REF]. Thus, materials' quantity takeoff can be extracted, work definitions and sequences can be defined, so the actual construction progress can be simulated in a virtual environment [START_REF] Khemlani | Top criteria for BIM solutions[END_REF].

Figure 3. BIM implementation through building lifecycle [START_REF] Dispenza | The daily life of building information modeling (BIM)[END_REF] However, unlike the Airbus example, where Airbus is clearly the client, manager and coordinator of the DMU through the development stages, the fragmented nature of the construction industry means that the handling of BIM is much more fragmented and complex in the construction sector. The issues of ownership and management of BIM across the different phases remain unclear to most players in the industry. As a result, when compared to the role of Airbus in the development DMU, the following generic points can be stated about BIM: (1) BIM discussion has exploded as much in academic research as it has gained the attention of the industry, (2) The role of clients as champions of BIM is critical to the implementation of BIM in practice [START_REF] Coates | The key performance indicators of the BIM implementation process[END_REF], (3) Unlike, the aerospace industry that has very few, but dominant global players, in the fragmented construction sector the government agencies, regulatory authorities and public clients across different regions have also had to play an important role in binding the use of BIM across different phases of construction projects in the corresponding regions [START_REF] Gu | BIM adoption: expectations across disciplines[END_REF].

The discussion on versioning aspect of DMU and cDMU also highlights the following key differences in the context and scope of BIM in construction sector, visà-vis the use of DMU in the aerospace sector: (1) Unlike the aerospace sector, designs in construction projects are typically unique and rarely re-used for multiple instances. This means the concepts of Model Versions in BIM are entirely different to Model Versions in DMU. Instead, versioning in BIM is typically associated with aspects such as levels of detail (LOD), solution alternatives and different stages of model development [START_REF] Gu | BIM : Expectations and a reality check[END_REF], (2) Since versioning in BIM is more about model coordination within the same project rather than across different instances of the product, instead of the concept of Head of Versions, typically the concepts of Reference Models is used in BIM development. Typically the Reference Model from one discipline is used to coordinate the models of all the other disciplines to ensure version compatibility, and (3) Unlike the aerospace industry where the DMU can be directly used for fabrication, the lack of automation from design to fabrication in construction industry means that the Reference Models typically vary across the different phases of the construction projects, because the as-built facility typically varies from the as-designed model resulting from the changes and inaccuracies in the construction phase. In the design phase, the architecture model is typically the Reference Model, while in the construction phase, the construction model may become the Reference Model. Similarly, it is expected that the as-built model of a facility should become the Reference Model in the maintenance phase. However, the use of as-built models is rare in practice. The lack of automation between design and fabrication also explains why the LOD is an important aspect of BIM models [START_REF] Singh | Challenges for integrated design and delivery teams in AEC[END_REF].

In summary, both DMU and BIM are identical in their object-oriented approach, but the differences between them result from their context and the products they create, which have their own metadata requirements. In general, the benefits of both IT-solutions in product development are similar, fundamentally derived from the way in which the user groups can contribute to the shared data model, and use the information [START_REF] Airbus | Setting new standards with the A350 XWB Digital Mock-Up[END_REF][START_REF] Dispenza | The daily life of building information modeling (BIM)[END_REF]. The most common benefits of DMU [START_REF] Airbus | Setting new standards with the A350 XWB Digital Mock-Up[END_REF][START_REF] Garbade | DMU@ Airbus-Evolution of the Digital Mock-up (DMU) at Airbus to the Centre of Aircraft Development[END_REF] and BIM [START_REF] Khemlani | Top criteria for BIM solutions[END_REF] include:

• Improved coordination in design through visualized object-oriented data which enables improved design management and change control • Ability to perform simulation and optimization products' performance • Ability to perform cost performance analysis and cost impact of any change in design and manufacturing process • Reduction in manufacturing risks through identification of manufacturability issues, clash detection, schedule and cost simulations, etc in design process. • Creation of operation and maintenance information database

Use of models in maintenance of end products a. Aircraft Continuing Airworthiness Management

Aircraft continuing airworthiness is managed by Continuing Airworthiness Management Organization (CAMO). As stated in European Aviation Safety Agency's directives for maintenance organizations [START_REF]Acceptable Means of Compliance and Guidance Material[END_REF], "Continuing Airworthiness means all of the processes ensuring that, at any time in its operating life, the aircraft complies with the airworthiness requirements in force and is in a condition for safe operation". CAMO usually is the operator of the aircraft, whether the aircraft is owned or leased. The organization itself is not responsible for the actual maintenance work, but ensures that all needed maintenance and repairs are performed as demanded. Actual maintenance work is done by authority approved maintenance organization [START_REF]Continuing Airworthiness Requirements -PART-M. Acceptable Means of Compliance and Guidance Material[END_REF].

Aircraft maintenance consists of scheduled and unscheduled maintenance. Unscheduled maintenance is corrective maintenance; repairs of defects. Scheduled maintenance aims to prevent decline of the aircrafts airworthiness. Scheduling is based on aircraft's flight hours, flight cycles and overall time in service [START_REF] Aubin | Aircraft Maintenance: The art and science of keeping aircraft safe[END_REF]. To have the ability to execute the maintenance to secure aircraft's airworthiness, a wide set of data on aircraft and its maintenance procedures is needed. This data can be divided to maintenance data, and aircraft configuration and condition data. Maintenance data is the collection of documents to regulate and guide the aircraft maintenance. It includes aviation authority issued requirements, airworthiness directives and technical data provided by OEM. Aircraft configuration and condition data is general identification information on aircraft and components installed on it. It describes the status of airworthiness directives and history of defects, maintenances and modifications. Records of operational data are also part of aircraft's condition information [START_REF] Garbade | DMU@ Airbus-Evolution of the Digital Mock-up (DMU) at Airbus to the Centre of Aircraft Development[END_REF]. Regulated by the authorities [START_REF]Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes[END_REF], the OEM provided technical data should be followed, as shown in Table 1

DMU in Aircraft Maintenance

The subject of utilizing the DMU in aircraft maintenance, or any product maintenance, has not been widely addressed. To open a discussion on how the DMU could be deployed in aircraft continuing airworthiness management, a master's thesis was written on the topic. The thesis approaches the topic from user's point of view by conducting interviews with two CAMOs [START_REF] Garbade | DMU@ Airbus-Evolution of the Digital Mock-up (DMU) at Airbus to the Centre of Aircraft Development[END_REF]. Results of that thesis are presented here.

Data management to secure aircraft continuing airworthiness is not a new subject; it is a mandatory requirement from aviation authorities. For that reason, sophisticated maintenance management software have been developed and used to manage aircraft configuration and condition, and maintenance data. However, current challenge with those data, especially OEM provided technical data, is that it represents aircrafts in parts. Having a full 3D-model of the whole aircraft would enable the aircraft parts to be examined in their actual context, the aircraft. This visual and spatial information gives better view on the part locations and access to them. Better visualization improves accuracy of maintenance planning and troubleshooting by facilitating the location of components, estimation of man-hours for maintenance tasks, and analysis of potential defects. This would reduce Aircraft on Ground (AOG) -time and make CAMO's operations more efficient.

The key challenges to the deployment of DMU in aircraft airworthiness management are limited resources, competence, time and money. To be able to use DMU as a reliable reference, it should be kept updated so as to correspond to the aircraft configuration and condition at any given point of the aircraft's lifecycle. Another challenge arises from the ownership of the DMU and that the DMU is the core competence and intellectual property of the OEM.

b. Facilities Maintenance

Facilities maintenance is the continuous process of service provision required to maintain a facility and its environment through its service life. These services encompass the entire activities required to assure that a built environment will perform the functions for which the facility was designed and constructed [START_REF]Whole Building Design Guide, Facilities operation&maintenance[END_REF]. O&M phase of a construction project typically includes scheduled, and preventive and emergency maintenance activities of major building systems. Managing the maintenance of facilities can be difficult on the O&M phase owing to various types of equipment and facilities. Furthermore, it is inconvenient for maintenance staff to maintain those facilities by relying on paper-based documents.

In contrast to the aviation industry, which has the legal obligation to regulate the maintenance of both private and passenger aircrafts and their lifecycle information, such practices and regulations are not common in construction industry. Although many governmental organizations have the responsibility to maintain their buildings, there is no obligation to maintain private buildings. Nonetheless, manuals and strategic maintenance guidelines may be agreed upon through contractual agreement between the owner and contractor. These manuals and guides typically describe the basic information requirements for effective maintenance activities, such as:

• Architectural and structural components of the facility like ceiling surfaces, floor coverings, roofing, and walls. • Design details, floor plans, spaces and zones, and as-built drawings.

• Environmental considerations, required tools and equipment for safety issues, safety instructions of building systems. • Equipment lists, descriptions, maintenance and repair guides, operation manuals. • Preventive maintenance schedules, procedures, logs, troubleshooting guides, removal and replacement instructions of building systems, warranty information. • Operation instructions of building systems, operation logbooks, start-up and shut-down procedures, emergency operating instructions. • Descriptions of all systems in buildings, assembly and components diagram, utility connections and cutoff plans.

The listed information requirements are rarely applied to that extent, because of the difficulties to structure and digitally hand them over to a centralized source. As reported by National Institute of Standards and Technology (NIST), "an inordinate amount of time is spent locating and verifying specific facility information from previous activities. Much valuable data associated with the design, construction and operation of a facility is lost during its lifecycle" [START_REF]Cost analysis of inadequate interoperability in the U.S capital and facilities industry[END_REF].

BIM in Facilities Maintenance

BIM can provide a shared resource and information sets about a facility's structure, functions and technical systems (mechanical, electrical, plumbing, lighting, etc.), including product manufacturers, if available and added to the model. However, construction contracts rarely stipulate providing or using these potential information in BIM models for maintenance activities, and hence, there are very few cases on the actual use of BIM for facilities management. Instead, there are many other technologies that can also exchange the facility data. Building automation systems (BAS) or Building Management Systems (BMS) most often handle the operation of building mechanical, electrical, plumbing (MEP) and lightening systems. Integrated Work Management Systems (IWMS) or Computerized Maintenance Management Systems (CMMS) support maintenance activities, work orders, space management, personnel management, etc. However, the exchange and re-usability of the data in these systems and the fragmented nature of AEC industry make the information transfer among project stakeholders challenging, especially through BIM [START_REF] Madritsch | Successful IT implementation in facility management[END_REF].

Therefore, an important point for the success of BIM for facilities maintenance activities is an accurate and structured specification of the BIM data and interoperability of BIM and maintenance software. Construction Operations Building Information Exchange (COBie) has been developed for O&M data handover [START_REF] East | bSa Construction Operations Building Information Exchange (COBIE): Means and Methods[END_REF]. COBie is a rapidly evolving standard to capture information, such as zones, rooms (spaces), equipment and components, tests and certificates, safety and emergency plans, start-up and shut-down procedures, etc. in BIM electronically during design and construction, to provide it to facility managers in a spreadsheet format. It can potentially eliminate the inefficient process of transferring large amounts of paper based documents or electronic data within facility management systems (CMMS, BAS, etc.). To establish the common practice and adoption of BIM-based maintenance management, contractual agreements are needed to stipulate the use and update of COBie data by the project stakeholders. In addition, the COBie standards and templates need further maturity and integration with different BIM applications.

Conclusion

This paper presents a comparison of BIM and DMU, two different IT-driven solutions applied in AEC and aviation industry respectively. In this paper O&M phase of the specified industries' products (buildings and aircrafts) are reviewed, and BIM and DMU's value adding functions are discussed. It is proposed that even if the industries and their related domains/products are different, both BIM and DMU apply similar functions for their individual products. However, it is important to understand and analyze the specific circumstances during each domain's lifecycle to figure out the specific needs, strategies to apply related IT-driven solutions. For both solutions, number of issues and potential improvements arise in data management features of related software applications. Potential improvements by means of visualization, data collection/updating and information transfer may ease the BIM/DMU based activities during lifecycle, and make it more efficient.

Future work should include the application of both BIM and DMU for different phases of the lifecycle by highlighting specific workflow issues. Since O&M phase of both industries include various types of data coming from design and production/construction phases, the specific information requirements for O&M should be clarified and data/information transfer between these phases may also be a potential area to search.

Table 1 :

 1 : OEM Technical data to be provided, as per the regulations[START_REF]Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes[END_REF]

	Aircraft	Instructions for maintenance	Operation
	Description


Jupp Jr

Similar Concepts, Distinct Solutions, Common Problems: Learning from PLM and BIM Deployment

Keywords: Building information modelling, product lifecycle management, business processes, information systems, information technologies

This paper describes the similarities and differences between Product Lifecycle Management and Building Information Modelling concepts, focusing on integration issues relative to their methods, information systems, effects and criticisms. In this literature based discussion, the authors show that the two concepts share fundamental similarities but are distinct in their scope and level of integration as well as maturity of process and workflow management. The paper highlights several common problems and aims to provide guidance for deployment initiatives.

Introduction

A variety of lifecycle management concepts enabled by advances in business process integration and information technology (IT) have been developed in various sectors. In manufacturing sectors, Product Lifecycle Management (PLM) has evolved to provide platforms for the creation, organization, and dissemination of product-related knowledge across the extended enterprise [START_REF] Ameri | Product Lifecycle Management: Closing the Knowledge Loops[END_REF]. In the construction sector, a renewed focus on lifecycle processes is emerging within the BIM (building information modelling) paradigm, an object oriented approach to creating, managing and using construction project data. Whilst both are relatively new concepts, PLM stands as a more established approach, seeing steady uptake since the mid-1990s. BIM has only recently become the accepted term for the production and management of a built asset's information throughout design, construction and operations [START_REF] Venugopal | Semantics of model views for information exchanges using the industry foundation class schema[END_REF].

Recently comparisons have begun to relate PLM and BIM concepts, contrasting the functionalities and capabilities of their methods and systems, see [START_REF] Ford | Product Life Cycle Data Management: A Cross-Sectoral Review[END_REF][START_REF] Aram | Integration of PLM solutions and BIM systems for the AEC industry[END_REF][START_REF] Jupp | Incomplete BIM implementation: Challenges and role of product lifecycle management functions[END_REF]. These studies are beginning to examine their similarities and differences; however a number of open questions remain relative not only to their concepts, methods, and systems but also their intended effects and criticisms. In reviewing the literature, the authors present a comparative analysis that explores these questions to provide a broader account of PLM and BIM relative to the unique structural characteristics of each sector. The remainder of the paper is divided into four sections. Sections 2 and 3 review PLM and BIM concepts, information systems, effects and criticisms. Section 4 compares and discusses their main attributes and shared problems, before closing the paper with a discussion and summary of research contribution.

Product Lifecycle Management

Stark [START_REF] Stark | Product lifecycle management: 21st century paradigm for product realization[END_REF] broadly describes PLM as simply the activity of managing products effectively across their lifecycle. Understanding the evolution of PLM is helpful to expounding Stark's definition. Emerging from product data management (PDM), which provides data management capabilities [START_REF]PLM vs PDM Definition[END_REF][START_REF] Mostefai | Data Integration in a PLM Perspective for Mechanical Products[END_REF] PLM extends beyond the engineering aspects of a product to provide a shared platform for the creation, organization, and dissemination of all product-related knowledge across the extended enterprise [START_REF] Ameri | Product Lifecycle Management: Closing the Knowledge Loops[END_REF]. PLM is thus a strategic business approach to the collaborative creation, management and exchange of product lifecycle information [START_REF] Cimdata | All About PLM[END_REF].

Concept and Methods

The general idea behind PLM is to serve up-to-date data, information and knowledge in a secure way to all people who are part of the product lifecycle [START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF]. Information is produced by a variety of participants at different levels of detail in diverse functions inside and outside a firm [START_REF] Sudarsan | A product information modeling framework for product lifecycle management[END_REF]. Complexity increases when moving from data towards knowledge, with data and information easier to store, describe, and manipulate [START_REF] Ameri | Product Lifecycle Management: Closing the Knowledge Loops[END_REF]. The range of data, information and knowledge across an extended enterprise must be integrated correctly throughout the lifecycle. Various methods, systems and engineering tools are required to organize, store, access, convert and exchange these different forms correctly and seamlessly. Consequently generating appropriate data, information, and knowledge structures is critical [START_REF] Mostefai | Data Integration in a PLM Perspective for Mechanical Products[END_REF]. IT infrastructure is therefore central to PLM, including hardware, software, and Internet technologies, and underlying representation and computing languages. In manufacturing industries, the product lifecycle is typically divided into three distinct phases: beginning/middle/end of life (BOL/MOL/EOL). PLM transverses these phases and assists a corporation and its extended enterprise in meeting functional-and data-level requirements [START_REF] Lee | An architecture for ubiquitous product life cycle support system and its extension to machine tools with product data model[END_REF]. Together numerous methods, systems and engineering tools form the systems architecture of a PLM solution. Currently, these are mostly deployed in the BOL phase to support design and development. However the application of IT in MOL and EOL phases is increasing as customer needs and technologies mature [START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF].

PLM functionality is achieved via 'system components', including the IT Infrastructure as well as a Product Information Modelling Architecture (PIMA), a Development Toolkit, and a set of Business Applications [START_REF] Sudarsan | A product information modeling framework for product lifecycle management[END_REF]. PIMA includes product ontology and interoperability standards. A development toolkit provides the means for building Business Applications and extends PLM functions to include kernels (e.g. geometry), visualization tools, data exchange standards and mechanisms, and databases. Business applications provide PLM functionalities to process corporate intellectual capital [START_REF] Sudarsan | A product information modeling framework for product lifecycle management[END_REF]. There are different types of functional-and data-level requirements of PLM system architectures. According to Jun [START_REF] Lee | An architecture for ubiquitous product life cycle support system and its extension to machine tools with product data model[END_REF], the functional-level requirements of PLM are defined by the large amounts of structured and unstructured data that are created, updated, transferred, removed, reused and stored in several application systems across the extended enterprise. The requirements for handling this include: real-time data acquisition, closed-loop information flow, interoperability between devices and application systems, integration with existing systems and services and the collaborative environment [START_REF] Lee | An architecture for ubiquitous product life cycle support system and its extension to machine tools with product data model[END_REF]. Data-level requirements relate to product and productrelated data (e.g., business, maintenance and expiration data). For seamless interface between product and product-related data requirements surround the use of standardized data, data interoperability, product information traceability, data encryption, and user authentication [START_REF] Lee | An architecture for ubiquitous product life cycle support system and its extension to machine tools with product data model[END_REF].

Information Systems and Technologies

Depending on the level of integration, implementation and system architecture, the deployed information systems may include: Systems engineering (SE), Product design, Product and portfolio management (PPM), Engineering data management (EDM), Manufacturing process management (MPM), PDM, Enterprise resource planning (ERP) and and supply chain management (SCM). To limit the scope of this discussion, our review utilizes Crnkovic's PLM integration taxonomy [START_REF] Crnkovic | Implementing and Integrating Product Data Management and Software Configuration Management[END_REF] to rationalize the information systems utilized. Crnkovic defines three levels of integration: full, loose and no integration.

Full integration: a package with all functions using common structures, data, user interfaces and application programming interfaces (APIs). The integration model has a layered architecture. The lowest tier is the data repository layer, which includes databases, file systems and information models [START_REF] Crnkovic | Implementing and Integrating Product Data Management and Software Configuration Management[END_REF]. The middle tier is the business layer, with tools and services to support business logic. The uppermost tier is the user interface layer. All layers are connected to each other using standardized APIs. A single database for all the data is superior in terms of data quality, because loss of data in exchange between systems is reduced and duplication is low [START_REF] Crnkovic | Implementing and Integrating Product Data Management and Software Configuration Management[END_REF].

Loose integration: the different information systems operate more independently and store data in their own repositories. The information models in the repositories are different and can only be accessed from native tools. Information exchange between tools is carried out by additional interoperability functions. The advantage is that it does not require a common information model and enables the use of tools from different vendors. Disadvantages stem from the lack of a common information model, requiring interoperability functions, through middleware mechanisms acting as a 'middle layer' in PLM integration. Data inconsistencies pose a risk.

No integration: all data transfers are done manually, increasing the risk of data inconsistencies, human error, and the lack of standardization in information models. The data update routines such as import and export functions need to be well defined.

Effects

As companies use PLM in different ways, the extent of its effects is contingent on the field of business and level of integration. The business case for PLM is usually linked to the reduction of operational level information systems and an increase in operational excellence [START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF]. Manufacturers can speed up the realization of complex products. Product engineers can shorten implementation and engineering change approval cycles across the extended design team. Purchasing agents can work more effectively with suppliers to reuse parts. Executives get a high-level view of all important information, from details of the manufacturing line to parts failure rates culled from warranty data and field information [START_REF] Vainio | Comparative Research of PLM Usage and Architecture[END_REF]. The effects of PLM may also include staff reduction, data integration, standardization, access to timely and complete information, improving customer service, creative and collaborative work methods; customization of products based on complex customer desires, lead-time reduction, prototype cost reduction, and reduction in late product changes [START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF].

PLM centres on the BOM (bill of materials), with methods, processes and legacy tools needing to be modular, follow standards and be reusable [START_REF] Sudarsan | A product information modeling framework for product lifecycle management[END_REF]. PLM integration must be flexible to react to changes in the market, organization structure, business processes, product and tools. Consequently data, processes and software should ideally be aggregated to reduce system complexity [START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF] and the use of open data standards is crucial. Numerous standards have emerged for the horizontal and vertical integration of PLM systems. MIMOSA and ISO are two leading bodies that develop such standards employed in PLM [31]. Examples include the STEP-Standard for the exchange of product model data (ISO 10303), covering data exchange through life. There are ongoing efforts to make STEP universally available using XML and UML standards. MIMOSA's OSA-EAI (OSA for Enterprise Application Integration) and OSA-CBM (Open System Architecture for Condition Based Maintenance) are also established and utilised [START_REF] Koronios | Integration Through Standards: An Overview of International Standards For Engineering Asset Management[END_REF].

Criticisms

There are several unique challenges related to business process and technological integration relative to the PLM concept, as documented in several case studies, see e.g., [START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF][START_REF] Vainio | Comparative Research of PLM Usage and Architecture[END_REF][START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF]. Many criticisms of PLM can be traced to: (a) failings in PLM technology; (b) 'elusive standard engineering processes' as the foundation for PLM; (c) organizational issues; and (d) dynamic environments.

Failings of PLM Technology: PLM solutions lack maturity; this is mostly due to high levels of technical complexity and incomplete data standards. Whilst PLM's functional footprint is improving, it is common to require multiple proprietary solutions to address each company's needs spanning the development lifecycle. PLM solutions are typically a complex collection of tools that are often loosely connected [START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF]. Depending on the overall architecture, the functionalities of systems and tools used might overlap causing redundancies, rework and data quality deterioration. Also, data standards and corporation-wide integration architectures are ongoing development activities and are not fully established [START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF][START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF].

Elusive Standard Engineering Process: Whilst the development process may be viewed as standard across product groups and businesses, once details of how a company actually develops a product (how decisions are made, who is involved at various stages, how partner collaborations are executed, etc.), the nuances of a company's product development practices become visible [START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF]. The practices of seemingly similar product development and engineering processes can differ wildly across companies and between products developed in the same company.

Organizational Issues: Due to the diversity of engineering tools and subsystems there is a tendency to delegate PLM deployment to engineering executives, who traditionally manage technology rollouts [START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF]. This approach works for choosing point solutions, e.g., CAD tools, but studies show that it does not work well for enterprisewide integration platforms [START_REF] Vainio | Comparative Research of PLM Usage and Architecture[END_REF][START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF]. The main criticism being that different business functions generate and deal with product data in disparate ways. Related criticisms include: improper executive management expectations, frustrated end-users, high implementation costs, and evasive returns on investment [START_REF] Hewett | Product Lifecycle Management: Critical Issues and Challenges in Implementation[END_REF].

Dynamic Environments: The systems and practices that underlie lifecycle management are continuing to undergo significant changes. New and emerging IT, rapid globalization of businesses, and evolving core functions such as collaborative design and outsourced manufacturing force companies to continually re-examine their product development practices, which can be costly and time consuming [START_REF] Stark | Product lifecycle management: 21st century paradigm for product realization[END_REF][START_REF] Terzi | Product lifecycle management -from its history to its new role[END_REF].

Building Information Modeling

BIM is an object oriented approach to creating, managing and using various geometric and non-geometric data in a construction project. While conceptually BIM can be used across all the phases of a project lifecycle, starting from design to the demolition of the built environment, in practice, the level of integration and maturity of BIM usage across different phases is contingent on multiple factors defined relative to products (both the design artefact and tools), processes (e.g. operational, methodological, business, legal) and people (e.g. organizations, stakeholders, culture).

Concept and Methods

The evolution of BIM can be traced to simultaneous developments across CAD and information systems; both facilitated by progress in computing power, the emergence personal computers and the internet. The development of the BIM concept and methodology can be explained on the basis of four attributes: 1) representation, 2) information management, 3) inbuilt intelligence, analysis and simulation, and 4) workflow management.

Representation is integral to design, and it has driven the development of BIM in at least two ways. Firstly in terms of design cognition; as processing capabilities improved, computational tools moved from 2D drafting to 3D models, making visualization and working with complex geometries possible. This move from symbolism to virtualization initially led to photo-realistic renderings (based on solid geometry) and later to intelligent object-oriented models (replacing solid geometry). Second, at the level of communication and collaboration; representations used across multidisciplinary design teams demand greater specification of easily comprehended and disambiguated information. This requires higher levels of detail and accuracy in the geometric and non-geometric information contained in object-based models.

While representation and visualization is also part of documenting project-related information, it is equally important to be able to record, manage and use all other forms of building-related data, information and knowledge generated across the project lifecycle. Accordingly, document and information management capabilities that were developed in pre-BIM tools (as an independent set of specifications, documents and spreadsheets), have merged and evolved with BIM applications as information that is typically embedded, appended or linked to object-based models. Linking between all forms of geometric and non-geometric data is a critical aspect of BIM. Consequently, traditional users of electronic document management systems -such as contractors and project managers -have the expectation that BIM provides similar information management capabilities, with the added advantage of visualization. In construction, this typically takes the form of a BIM model server (see [START_REF] Singh | A theoretical framework of a BIM-based multidisciplinary collaboration platform[END_REF] for a discussion). Depending on the level of BIM implementation and maturity these systems may or may not be enabled in the project environment.

The object-oriented premise of BIM enables integration of CAD and information management capabilities. In doing so, it is possible to intelligently link different objects with relationships and constraints, allowing various forms of automated analysis and simulation, ranging from environmental and structural analysis to cost estimating and construction scheduling. Various forms of building compliance 'checks', such as interference and clash detection, are now common. Increasingly, BIM applications are becoming knowledge-based systems with more and more domain knowledge being integrated. Consequently, the number of BIM applications is expanding rapidly, each catering to different discipline-based requirements.

With the complexity, intelligence and number of BIM applications growing, information and workflow management is critical. Given the richness of buildingrelated and project-related information it is desirable to design and plan the project and discipline-specific workflows. Design process optimization is receiving growing attention in recent efforts to model information flow and develop BIM workflow management frameworks, leading to new cloud-based approaches (see e.g., [START_REF] Rezgui | A governance approach for BIM management across lifecycle and supply chains using mixed-modes of information delivery[END_REF]).

Information Systems and Technologies

BIM shares many characteristics with PLM. The platforms supporting BIM resemble Crnkovic's [START_REF] Vainio | Comparative Research of PLM Usage and Architecture[END_REF] loose or no integration levels. Technologically, some of the key characteristics of BIM are: 1) Open data standards, 2) Centralised and decentralised BIM, 3) Information exchange standards, and 4) Data and information structures.

To achieve interoperability between BIM applications, open file formats such as the Industry Foundation Class (IFC) have been developed. IFC files can be viewed in most applications but modifications have to be undertaken in the native format and converted back to IFC. This process is error prone. Even if most geometric data can be completely exchanged, the intelligence is often lost in the transformation. Another information exchange method is sharing data through middleware or APIs, however this requires that different links are established between each application.

The BIM database can either be centralized or decentralized. In a centralized approach, information from e.g., a central IFC-based model must be exported, modified within a native format and imported back into the central model using IFCs. This 'roundtrip' is often not a viable option due to interoperability issues [START_REF] Törmä | Managing building information as a set of interrelated partial models[END_REF]. Singh et al. [START_REF] Singh | A theoretical framework of a BIM-based multidisciplinary collaboration platform[END_REF] highlight the challenges of system and sub-system integration in a centralized BIM-server approach. Due to this complexity, a decentralized, distributed information management approach is increasingly being considered [START_REF] Törmä | Managing building information as a set of interrelated partial models[END_REF]. In a decentralized approach, collaboration can occur at two levels: (1) within a single organisation or discipline using similar tools, and (2) across different discipline-specific models shared and combined using IFCs. IFC standardization has adopted a 'use case centred' approach [START_REF] Buildingsmart | MVD Process[END_REF]. Different use cases and information exchange requirements are specified in Information Delivery Manuals (IDM). IDMs together with other model management protocols have given rise to a variety of policy documents such as BIM Management, Coordination and Execution Plans [START_REF] Holzer | BIM's seven deadly sins[END_REF].

Object-based building models include both non-modifiable internal data structures, and information structures that enable model management. NBIMS (National BIM Society) lists three potential reference standards that can be used to structure model information; IFC, as discussed above, the Construction Specifications Institute (CSI) OmniClassTM, and CSI IFDLibrary [START_REF] Nibs | US National BIM Standard: Version 1, Part 1: Overview, Principles and Methodologies[END_REF]. OmniClass provides a standardized basis for classifying information created and used by the North American AEC (Architectural, Engineering and Construction) industry. The IFD initiative, based on ISO standards and driven by buildingSMART, aims to find a way to create and catalogue a data dictionary of building objects and bring disparate sets of data into a common view of the construction project or asset. In addition to reference standards, a variety of metadata is also contained in the BIM model, e.g., information related to object creation and history. A recent development in BIM systems is towards distributed transactional models, e.g. the DRUM concept [START_REF] Törmä | Managing building information as a set of interrelated partial models[END_REF], which aims to create a mechanism to manage linked partial models such that building information can still be distributed.

Effects

Effects of BIM are visible both at micro (project and organization) and macro (industry and national) levels. The potential benefits of BIM are best exploited through collaborative engagement of different stakeholders from early stages of the project. Accordingly, new forms of project delivery practices are emerging such as Integrated Project Delivery (IPD)an alliance-based relational contracting approach that aims to align the interests, benefits, roles, risks and responsibilities of all project stakeholder [START_REF]Integrated Project Delivery: A Guide[END_REF]; Big Rooma multidisciplinary BIM coordination office [START_REF] Dolan | Building A Hospital Out Of Bits And Bricks[END_REF]; and 'knotworking' occasional collocated and intense design sessions when distributed design teams physically get together to make rapid progress [START_REF] Engeström | Knotworking to create collaborative intentionality capital in fluid organizational fields[END_REF]. Furthermore, with increasing BIM maturity, its role and scope is expanding to different aspects and domains across the building lifecycle and specific topics for BIM, such as BIM for: facilities and operations management, lean construction, prefabrication, and safety.

At a macro level governments across many countries are mandating the use of BIM to facilitate productivity gains in the AEC sector. Among the various challenges in realizing these mandates is training enough BIM skilled and literate personnel.

Criticisms

BIM has received criticism on various issues, especially concerning, (1) data transfer and systems integration, (2) ill-defined terminology, scope and purpose, and (3) unstructured implementation processes. Data transfer and system integration: There are gaps in using BIM smoothly between conceptual design to detail design, design model to construction model, asdesigned to as-built data, etc. These interfaces need to be resolved for effective BIM usage. Also, the integration of BIM with advanced structural analyses techniques such as Finite Element Method has remained a challenge. While open standards have progressed significantly over the last two decades, the commercial interests of software vendors have also stunted the pace of development around interoperability.

Terminology, scope and purpose: The term and concept of BIM is unclear for many, with M in BIM being used interchangeably for models (product), modelling (process), and management (process). This needs to be resolved for stakeholders to reach a shared understanding on what they are committing to. Furthermore, the scope and purpose of BIM in a project is rarely defined clearly, leaving uncertainties about aspects such as the level of detail, information flow and modes of exchange of information across stakeholders, data transfer, model ownership and handover.

Unstructured implementation processes: One of the primary challenges to addressing macro level issues is to understand and plan around the key factors that drive and determine how and where BIM efforts are concentrated. For example, in Finland, the earliest BIM developments that were piloted in 1994, focused on later lifecycle management [START_REF] Björk | ISO DIS 13567: Proposed Intl. Standard for Structuring Layers in Computer Aided Building Design[END_REF]. However, as the pilot project led to greater interest in BIM, direct and immediate benefits were seen by design consultants and contractors. The resulting market forces led to BIM development concentrating on design and construction phases, while work in facilities and later lifecycle management came to a standstill. In recent years this development is seeing a revival, e.g., developments have looked to establish definition of as-built datasets for FM [START_REF] Teicholz | Owner BIM for FM Guidelines[END_REF], and the introduction of the COBie initiative (Construction Operations Building information exchange) for the exchange of IFCbased FM data [START_REF] East | Construction Operation Building Information Exchange[END_REF].

Discussion

PLM and BIM share some similarities regarding lifecycle management objectives and the nature of their practice-based criticisms, however they differ in critical areas concerning their underlying methods, scope of business, technological and enterprise integration, and their intended effects. This sections attempts to elucidate these similarities and distinctions so that valuable learning opportunities may be identified.

Similarities exist in the key objectives of PLM and BIM, which include functionalities that support and manage the creation, release, change and verification of product-related information. PLM and BIM platforms typically provide for the same core functions: management of design and process documents and models, development and control of BOM records, provision of electronic file repositories, inclusion of document and model metadata, identification of model content for compliance and verification, provision for workflow and process management for change approvals, control of multi-user secured access, and data export controls. However it should also be noted that whilst BIM platforms have designed to cover these areas, their level of IT maturity and process sophistication appears to be behind that of most PLM system architectures.

Like PLM, BIM aims to integrate people and data processes throughout the design, construction and operation of a product (or built asset). However it has only been in the last five to seven years that an increasing focus on the application of BIM throughout the whole building lifecycle has emerged and the significance of business systems and business process integration been acknowledged. The literature surveyed reveals a growing number of studies that consider a range of building lifecycle management issues, where much of this research has sought to bridge the interface between AEC processes and the activities of facility operations and management. BIM servers are now being developed to provide a large integrated data-and knowledge-base that can be leveraged not only in design and engineering but also in planning and management of component fabrication, construction operations, and facilities maintenance [START_REF] Beetz | Advances in development and application of an open source model server for building information[END_REF]. Thus research efforts to 'close the loop' and develop the BIM concept for business process integration for the whole building lifecycle are increasing. This increasing scope, functionality and value of BIM is a consequence of platform expansion targeting collaborative processes, shared resources and decision-making to support the whole lifecycle [START_REF] Aram | Integration of PLM solutions and BIM systems for the AEC industry[END_REF].

The adoption of a lifecycle perspective in any sector depends on multiple factors. Depending on the size, cost and complexity of an engineered product or built asset the design and production will normally adhere to discrete stages to form a system lifecycle. In construction, IT implementations that span project or life cycle stages are less established than in manufacturing sectors such as aerospace. The speed and breadth of adoption of IT across the extended enterprise is also greater in these sectors. PLM in manufacturing is therefore a more proven lifecycle integration solution. In construction, even despite BIM-enabled IPD approaches, the flow and management of information is still not fully integrated among all stakeholders. In developing and advancing the BIM concept it is therefore imperative to adopt an ecosystem approach to mapping the network of interacting AEC actors, corporate business processes, project processes, activities, methods and technologies.


Jupp Jr

BIM and PLM: Comparing and learning from changes to professional practice across sectors

Keywords: Professional practice, roles and responsibilities, knowledge competencies, stakeholder relations

This paper presents an analysis of PLM and BIM in relation to effects on professional practice. It draws on the experiences of both communities of practice to explain shifts in professional boundaries. A review of the literature explores the nature of changes triggered by PLM and BIM relative to new activities, roles and responsibilities, knowledge competencies, and relationships. The paper synthesises these changes and reflects PLM and BIM experiences against each other so as to discuss the continuing evolution of professional practice and identify lessons.

Introduction

With the increasing use of building information modelling (BIM), architectural, engineering and construction (AEC) professionals are experiencing radical changes to working practices. BIM as a new technology and approach reflects many of the changes, challenges and opportunities triggered by the introduction of Product Lifecycle Management (PLM) in the aerospace and automotive sectors almost two decades ago. In particular, changes to professional practice relative to the new activities, roles/responsibilities, knowledge competencies, and relationships required during the implementation of PLM, appear to reflect many characteristics reported in the literature on the adoption and deployment of BIM.

The differences between BIM and PLM chiefly surround their capacity for technical and organizational integration, leading to differences in their approach to data governance and information management [START_REF] Jupp | Incomplete BIM implementation: Challenges and role of product lifecycle management functions[END_REF][START_REF] Ford | Product Life Cycle Data Management: A Cross-Sectoral Review[END_REF]. These characteristics together within context-based structural differences highlight other differentiators relative to discipline-based technology applicationse.g., differences in tools, BIM/PLM platform specification, and data requirements. However BIM and PLM also share a number of similarities relative to their approach to data sharing, project management, organisation of teams around deliverables and timelines, and object-based visualisation activities. The challenges that follow on from these shared characteristics may provide fertile grounds for sharing lessons learned. Issues surrounding changes to professional practice and cultural change are continuing to plague the practical deployment of both the BIM and PLM concepts across their respective sectors. These challenges stem from a variety of new activities that are changing the nature of professional roles and responsibilities at both the firm and project level. These changes not only require the development of new technical skills but importantly new knowledge competencies and stakeholder relationships.

This paper presents an investigation into BIM and PLM and their common ground relative to changes in working practices. The experiences of the BIM and PLM communities reflected in case study research can be used to understand the practice-based issues challenging each sector. The construction industry is still in the early phases of BIM adoption and therefore it stands to benefit most (as a more recent paradigm) in learning from PLM based case studies of professional practice and cultural change. However whilst by comparison the application of PLM in the automotive and aerospace sectors is a more established concept, PLM is still seen as a recent phenomenon in these industries and therefore also stands to benefit from lessons of BIM implementation due to the construction sector's (arguably) more challenging structural and organizational attributes. The paper proceeds with a review of relevant literature that reports on the nature of the practice-based changes triggered by the PLM and BIM concepts relative to new professional activities, roles and responsibilities, knowledge competencies, and stakeholder relationships. The paper then synthesises the changes to professional practice and reflects the two experiences against each other so as to discuss the continuing evolution of professional boundaries and identify lessons for each industry. The paper closes with a summary of perspectives reflected in the literature.

PLM and New Working Practices

The manufacturing industry has in the past few decades seen rapid advances in the adoption and deployment of PLM. The three fundamental concepts of PLM are to enable: (1) Universal, secure, managed access and use of product definition information; (2) Maintenance of the integrity of that product definition and related information throughout the life of the product; and (3) Management and maintenance of the business processes used to create, manage, disseminate, share, and use the information [START_REF] Cimdata | All About PLM[END_REF].

New Activities

The PLM concept emerged from Product Data Management (PDM) to primarily manage design files created by CAD tools and since PLM tools consistently evolved in various dimensions [START_REF] Cimdata | All About PLM[END_REF]. In terms of scope, offered services have expanded to cover not only product definition and design phases but also manufacturing and operations. This expansion has led to PLM systems acting as a hub connecting intangible asset information (i.e. virtual products of design and analysis activities) to physical assets information managed by such systems like Enterprise Resource Planning (ERP) and Customer Relationship Management (CRM). Since the capabilities of PLM systems have been enhanced, it has resulted in new processes, activities and tasks for project engineers, management and administration staff surrounding the capture, management, and preservation of the created information for the entire product portfolio of a company rather than a single project or product as use to be the case.

Consequently a common feature of PLM processes is that implementation requires changes to activities relative to the organization and its systems and conventions [START_REF] Kärkkäinena | Assessing Maturity Requirements for Implementing and Using Product Lifecycle Management[END_REF]. Changes to roles and responsibilities as well as skills and capabilities therefore follow. The implementation of PLM in an organization is therefore an extensive change process which is typically divided and managed in a series of smaller stages [START_REF] Kärkkäinena | Assessing Maturity Requirements for Implementing and Using Product Lifecycle Management[END_REF]. It requires various changes to strategic and operational (process-oriented) level activities as well as to IT system activities. These new activities must be carefully planned and coordinated. To that end, PLM information systems have undergone significant changes and cycles of evolution in the last three decades, from static, closed, standalone routine data processing activities to integrated knowledge and information management for the entire product portfolio. These new activities have been initiated by advances in CAD/CAM/CAE, data exchange platforms, visualization tools and modelling systems such as parametric modelling tools [START_REF] Rangan | Streamlining product lifecycle processes: a survey of product lifecycle management implementations, directions, and challenges[END_REF].

The PLM community have also grown substantially and covers the entire supply chain and extended enterprise which includes designers, suppliers, manufacturing partners, customers and other partners. PLM integrates with mechanical, electrical, electronics and software configuration management systems [START_REF] Rangan | Streamlining product lifecycle processes: a survey of product lifecycle management implementations, directions, and challenges[END_REF]. From such levels of integration new processes, methods and ways of working have emerged, together with new tasks and activities that must be mastered across the product engineering team with new interfaces established between engineering design teams and PLM administrators [START_REF] Hewett | Product Lifecycle Management (PLM): Critical Issues and Challenges in Implementation[END_REF].

New Roles and Responsibilities

PLM focuses on the entire life cycle of a product. As such, PLM isn't the responsibility of just one functional unit or department but rather a whole organization. PLM deployment requires that the PLM implementation team work closely with the cross-functional business teams for example, people from purchasing, order management, sales and marketing, and inventory management [START_REF] Hewett | Product Lifecycle Management (PLM): Critical Issues and Challenges in Implementation[END_REF].

Furthermore, PLM is often an enterprise-wide initiative and requires close integration of products, data, applications, processes, people, work methods, and equipment from across the supply chain [START_REF] Stark | Product lifecycle management: 21 st century paradigm for product realisation[END_REF]. PLM deployment in supply chains raises significant changes to roles and responsibilities and as a result, it is central to deployment initiatives that the roles and responsibilities of a company's product development team be determined at the outset. Likewise responsibilities in relation to partnering companies and their role in the process must be carefully considered [START_REF] Hewett | Product Lifecycle Management (PLM): Critical Issues and Challenges in Implementation[END_REF]. A number of new responsibilities within existing traditional roles can be identified in the PLM literature as well as how these roles are shared between administration executives (typically with an engineering background) and project engineers. Table 1 presents a summary of these new roles).

Traditionally manufacturing approaches do not consider the customer's and supplier's activities as part of the value creation process, and are merely value extracting processes [START_REF] Prahalad | Co-creation experiences: The next practice in value creation[END_REF]. In a PLM approach a company will more explicitly play some part throughout a product's life and potentially develop a more service-oriented approach.

New Knowledge Competencies

The shift of perspective from product delivery to a lifecycle approach represents a gap in knowledge for many manufacturing companies [START_REF] Hewett | Product Lifecycle Management (PLM): Critical Issues and Challenges in Implementation[END_REF][START_REF] Ericson | A service perspective on product development -towards functional products[END_REF]. Teaching institutions and professional bodies are seemingly behind in their alignment of current curriculums, assessments and accreditation relative to the needs of PLM and manufacturing industries. In the US this issue has been widely reported [see e.g., 10]. The call for versatile, cross functional employees that remain up-to-date with emerging technologies and are able to tackle the host of new responsibilities associated with through-life requirements and activities is common to both the aerospace and automotive sectors. Hutchins [START_REF] Hutchins | SME Speaks: Manufacturing Engineers Must Reduce Competency Gaps[END_REF], in an editorial, notes that manufacturing professionals in North America are being asked to perform a range of tasks not traditionally included in their professional scope of works. The workforce lacks the capabilities needed to undertake these tasks successfully, and urges more diverse knowledge competencies [START_REF] Hutchins | SME Speaks: Manufacturing Engineers Must Reduce Competency Gaps[END_REF].

The Society of Manufacturing Engineers has been researching "competency gaps" (specific capabilities that companies insist are lacking) and developing a 'Manufacturing Education Plan' [START_REF] Fillman | Entrylevel engineering professionals and product lifecycle management: a competency model[END_REF]. Academia have also responded to the needs of the changing workforce from one that is task oriented to one of that is competency based through the development of innovative curricula, such as Purdue University's initiative to develop a PLM-literate workforce [START_REF] Fillman | Entrylevel engineering professionals and product lifecycle management: a competency model[END_REF].

New Relations

A PLM approach attempts to uncover new relationships and rearrange the value network of actors. The most noticeable change in relations between different parties/stakeholders therefore stems from two fundamental changes to business focus. The first is the change in focus from a traditional product delivery business model to one that centres on the product in use, highlighting the role of the service owner and/or the customer role that the PLM concept is predicated on. This may extend relations of a firm with suppliers or even include new relations with product customers as is the case in a product-service delivery model. The second shift in focus follows on from this and relates to a more strategic approach to intellectual property creation and intellectual property management of a product, from its initial conception to retirement [13 citing 3]. Following on from these two shifts in business focus are a number of secondary factors such as the emergence of networked firms, globalization, changes in the customer base, mass customization, and changes to the mode of production. These factors have accelerated changes in relations between suppliers, manufacturers and customers [START_REF] Subrahmaniam | Product lifecycle management support: a challenge in supporting product design and manufacturing in a networked economy[END_REF].

IT is the key enabler of PLM support in these new relational networks. However, most case studies report that manufacturing firms are only partially integrated 'islands of information' and still lack a holistic view of 'users of information' [START_REF] Subrahmaniam | Product lifecycle management support: a challenge in supporting product design and manufacturing in a networked economy[END_REF]. The systems and technologies underpinning the PLM concept are still influenced by low levels of vertical integration [START_REF] Rachuri | Information sharing and exchange in the context of product lifecycle management: Role of standards[END_REF], a lack of interoperability across complex and disparate tools, and a lack of a 'plug and play' approach to PLM [START_REF] Subrahmaniam | Product lifecycle management support: a challenge in supporting product design and manufacturing in a networked economy[END_REF]. In an extended enterprise context, a PLM platform must connect product design and analysis processes to production and supply chain processes. Consequently the benefits of PLM can only be realized when horizontal integration of several disparate systems is achieved so as to be able to support wider partnering relations. This requires new approaches to collaboration relative to process planning.

BIM and New Working Practices

BIM is an emerging technology and collaborative process that in theory should facilitate the digital representation, exchange, use and reuse of all pertinent information about the life cycle of a building or facility from planning, design, construction, FM, and to the ultimate disposal [START_REF] Eastman | BIM Handbook: A Guide to Building Information Modeling, for Owners, Managers, Designers[END_REF]. In practice this is often only partially realised as a range of problems in 'closing the loop' in construction persist in entrenched construction industry practices. Like PLM, as a modeldriven approach to construction, the BIM concept relies on the mastering of new activities, ways of working, and responsibilities surrounding integration and sharing of resources.

New Activities

Like approaches to PLM, BIM emphasizes open communication and information exchange, collaborative decision making, early participation and contribution of knowledge and expertise by downstream stakeholders (contractors and suppliers), and greater levels of risk sharing [START_REF] Rezgui | A governance approach for BIM management across lifecycle and supply chains using mixed-modes of information delivery[END_REF]. BIM emphasizes integrated processes built around coordinated, reliable information about the life cycle of the facility. Consequently BIM introduces changes in working practices, both within an organization and across organizations [START_REF] Davies | Mapping roles in an altered landscape -The impact of BIM on designer-constructor relationships[END_REF], which are often difficult and painful.

Changes to collaboration and multidisciplinary teamwork relative to the implementation of BIM have occurred with model-based collaboration and network-based integration now gradually becoming the norm in these environments. The level of interaction is managed differently on projects according to different levels of technical and organizational integration [START_REF] Merschbrock | Unorchestrated symphony: The case of inter-organizational collaboration in digital construction design[END_REF]. Higher levels of interdisciplinary interaction and integration are often enabled by colocation arrangements which have spawned concepts such as the "Big Room" [START_REF] Cohen | Integrated project delivery: Case studies[END_REF] and 'knotworking'. Closer interdisciplinary collaboration between AEC stakeholders means that traditional role boundaries are become less distinct, and separations between responsibilities and areas of expertise are diminishing [START_REF] Davies | Mapping roles in an altered landscape -The impact of BIM on designer-constructor relationships[END_REF]. It also requires new project and technical management activities, such as new process management tasks surrounding the planning and execution of BIM arrangements between stakeholders, and new model management activities surrounding the coordination of discipline specific datasets. New activities are also emerging onsite with the use of 3D and 4D models during fabrication and construction [START_REF] Davies | Implementing "Site BIM": A case study of ICT innovation on a large hospital project[END_REF]. Most recently the activities of clients and facility managers have also begun to change relative to the deployment of BIM and the use of the as-built model for operations and maintenance [START_REF] Sabol | Building information modeling and FM[END_REF].

As was the case for PLM, these new AEC and FM activities have been initiated by advances in data exchange standards, new platforms and protocols and improvements to the visualisation and editing of information outside CAD and other modelling systems. Thus the community of users of BIM has also expanded to cover the entire supply chain, which includes designers, suppliers, manufacturing partners, customers and clients. From such new levels of coordination and integration requirements come new processes and collaborative ways of working, new tasks and activities that must be mastered across the design, delivery and operations team. Currently these new interfaces are being established mostly on an ad-hoc basis due to the project-based business focus of the sector.

New Roles and Responsibilities

Traditionally, AEC professionals have taken on separate and more strictly defined roles, delineated by a precise scope of works with established discipline-based responsibilities and contractual agreements. Professional disciplines have sought to transfer risk to other parties formally in contract arrangements [START_REF] Hughes | Construction contracts: law and management[END_REF]. Due to the interdisciplinary nature of BIM, traditional responsibilities relative to management, administrative and functional requirements are being challenged and professional boundaries being temporarily redrawn. Research indicates there is also a lack of clarity on whether these new requirements need to be one role or several, within an organisation or project framework [START_REF] Davies | Mapping roles in an altered landscape -The impact of BIM on designer-constructor relationships[END_REF].

In many case studies, the introduction of BIM is presented as simply an upgrade in the drawing production process from CAD to BIM. For these projects, the "BIM team", while described as a new function, is effectively an up-skilled version of the CAD operators or manual draftsmen from the pre-BIM project delivery days [START_REF] Merschbrock | Unorchestrated symphony: The case of inter-organizational collaboration in digital construction design[END_REF]. In other case studies the need for a new role or roles to implement BIM successfully are documented [START_REF] Rowlinson | Implementation of BIM in Construction: A comparative case study[END_REF][START_REF] Sebastian | Changing roles of the clients, architects and contractors through BIM[END_REF].

The proliferation of roles around BIM implementation may be seen as a reflection of these different approaches and the need for processes to allow different AEC stakeholders to contribute to model development [START_REF] Davies | Mapping roles in an altered landscape -The impact of BIM on designer-constructor relationships[END_REF]. Whyte [START_REF] Whyte | Managing digital coordination of design: emerging hybrid practices in an institutionalized project setting[END_REF] suggests that different approaches to drawing and model development are to some extent 'institutionalised' in existing professional roles, with architects taking a direct lead in model production, and engineers conducting the fundamental design and analysis but passing instructions to technicians for transformation into the required models, which appears to be causing issues relative to process planning and control. Davies et al. [START_REF] Davies | Mapping roles in an altered landscape -The impact of BIM on designer-constructor relationships[END_REF] argue that BIM roles within contractor organisations have more freedom to redefine their roles according to their core knowledge competencies. Indeed this seems to be the case where traditional construction management competencies are being updated relative to modelling scheduling (4D) and cost estimates (5D). Contractors appear therefore to be maintaining their own institutional boundaries more readily.

With regard to new professional boundaries, Barison and Santos [START_REF] Barison | An overview of BIM specialists[END_REF] have identified over 30 different job titles or descriptions for BIM specialists, with further role variations and combinations depending on project size or professional affiliation. A vast variety of new responsibilities on projects mediated by BIM can therefore be seen to be emerging. Table 2 summarizes the new roles and responsibilities identified from the literature.

New Knowledge Competencies

There is a large consensus relative to industry requirements for a new set of BIM knowledge competencies. Succar et al. [START_REF] Succar | An integrated approach to BIM competency assessment, acquisition and application[END_REF] have proposed an integrated definition of BIM competencies which comprise of personal traits, professional knowledge and technical abilities. Across the UK, US and Australia their respective construction industries are calling for the requirements of new abilities, activities or outcomes to be measureable against performance standards so as to hold education, training and/or development offerings to an acknowledged standard. Numerous BIM knowledge competencies have been categorised into useable clusters and competency taxonomies. [START_REF] Succar | An integrated approach to BIM competency assessment, acquisition and application[END_REF] include three complementary tiers -core, domain and execution. Competencies across the three tiers are numerous, and potentially thousands of competency items would be required to satisfy the integrated BIM competency definition. The required knowledge competencies can generally be mapped to the new roles and responsibilities that have emerged (illustrated in Table 2). New competencies can be identified relative to coordination and model-based requirements surrounding project management, technical management, technical skills development during project execution, contract administration, systems support through-life, and facilities management knowledge.

New Relations

The procurement process and contractual arrangements of a project have considerable impact on how BIM is implemented throughout the project team, and therefore on the resulting relations between parties. Under the traditional design-bid-build project framework, BIM is more likely to be used in isolation by a single or a small group of design consultant/s, or in some cases, in the construction stage alone, as there is no incentive or support for more collaborative engagement. More progressive arrangements such as alliancing, partnering, design-build, and most significantly integrated project delivery (IPD) [START_REF]Integrated Project Delivery: A Guide[END_REF] can facilitate and in some cases mandate increased levels of collaboration and greater integration of design and construction roles [START_REF] Davies | Mapping roles in an altered landscape -The impact of BIM on designer-constructor relationships[END_REF], particularly the increased involvement of contractor/subcontractors in the design phase of the project.

The emerging role of a third-party BIM specialist is also being used to assist different project partners with BIM implementation and modeling processes. While the use of such a person or team has the potential to bridge traditional role divisions or project stages, case studies to date suggest that it is most commonly seen in collaborative project frameworks and procurement methods (e.g., IPD), and not in design-bid-build. This highlights a significant difference between BIM and PLM initiatives where the introduction of a defined administrative PLM team appears to be a more significant and formal process, demanding new relations and where networks must be established with the product engineering team to ensure collaborative process planning and clearly defined data governance strategies .

Comparing BIM and PLM Experiences

There are a number of key differences between BIM and PLM concepts and their practical deployment. These differences can be seen to stem from the different structures, backgrounds and traditions of their respective industries. A comparison between the AEC and the automotive and aerospace sectors inevitably highlights each industry's unique characteristics and therefore any contrast between BIM and PLM should be mediated by differences in context. The automotive and aerospace sectors are more globalised and consolidated industries; in contrast, the majority of construction projects remain rooted in local contexts and IT adoption is low in a highly fragmented industry [START_REF] Green | Learning across business sectors: Knowledge sharing between aerospace and construction[END_REF]. Each sector also differs in terms of their technological intensity, which will in turn effect the implementation of the technology led BIM paradigm versus the product-driven PLM paradigm across their industries' respective supply chains. Further, due to the unique nature of construction, the project-centric companies that characterise this sector focus on issues of integration and transparency across multiple disciplines and organisational boundaries in their use and management of model-based technologies. Consequently requirements relative to data governance and model management centre on discipline-specific tools, activities and representations [START_REF] Rezgui | A governance approach for BIM management across lifecycle and supply chains using mixed-modes of information delivery[END_REF]; knowledge and information management is therefore also challenged by lower levels of technological sophistication throughout the construction supply chain. In the product-centric companies that characterise the automotive and aerospace sectors, the focus is instead on the overall business process and due to a more consolidated industry an enterprise level perspective can be fostered more readily. Thus PLM applications in these sectors have gained higher levels of traction due to the nature of a limited client base and higher levels of supplier specialisation and technological expertise. This in turn has caused suppliers to compete on technical expertise rather than on cost efficiency as is still the case in BIM-enabled construction.

In the last decade, widespread efforts have been undertaken to enhance various aspects of BIM platforms from their focus on internal modelling capabilities and software interoperability, to expand BIM's role to the entire lifecycle of a built asset. BIM servers [START_REF] Beetz | Advances in the development and application of an open source model server for building information[END_REF] are now being developed to provide a large integrated data-and knowledge-base that can be leveraged not only in design and engineering but also in planning and management of component fabrication, construction operations, and facilities maintenance. Hence, BIM's scope, functionality and value are only recently being expanded from merely modelling and visualization to a platform for collaborative processes and resourceful decision-making, aiming to support a whole life cycle approach. In contrast, PLM solutions have been serving as the basis for collaborative product definition, manufacturing, and service management for the past decade. PLM services have traditionally been provided for the automotive and aerospace industries but the demand for them has gradually expanded to include a broader range of manufacturing industries. With PLM, companies think of the standard processes, standard data and standard systems that they, and the numerous suppliers, customers, and partners, can use to save an enormous amount of time and money [START_REF] Stark | Product lifecycle management: 21 st century paradigm for product realisation[END_REF]. A lack of process commonality and standardization usually results in nonstandardized and suboptimal PLM implementations with a high cost of ownership being passed to companies implementing such process-oriented integrations [START_REF] Rangan | Streamlining product lifecycle processes: a survey of product lifecycle management implementations, directions, and challenges[END_REF]; with this being a key lesson for the construction sector. The support of PLM requires collaborative harmonization of a set of complementary and interoperable open standards and open source models that cover the full range of aspects of the products' life cycle [START_REF] Rachuri | Information sharing and exchange in the context of product lifecycle management: Role of standards[END_REF]. However even from a PLM perspective, the industry standards available for CAD systems are not yet widely accepted and popular as a useful form of data storage due to the lack of information they can hold [START_REF] Cheung | Product lifecycle management: state-of-the-art and future perspectives[END_REF]. Importantly, data exchange standards have often been criticized for their inability to capture well-defined business processes, work flow patterns/ systems, and underlying business rules. For organizations of any sector, a key issue in the implementation of PLM or an FM-focused BIM deployment is the transition processes required in adopting new solutions, i.e. moving from the old to the new system. There are technical issues, such as schema evolution, business rules phasing (old rules/policies to new rules/policies), data migration, customization, system maintenance, etc. [START_REF] Kärkkäinena | Assessing Maturity Requirements for Implementing and Using Product Lifecycle Management[END_REF]. For this reason collaborative process planning is crucial.

In considering the transition process surrounding PLM and BIM deployment another key lesson for practitioners concerns the fostering of new attitudes and perspectives towards collaboration and shared responsibility relative to implementation. PLM and BIM implementation must be driven by the requirements of product design processes rather than IT considerations, and therefore the bill of materials or product structure must remain at the centre of these process requirements. Such a perspective is arguably more difficult for AEC professionals to foster. Currently the main perception of the construction industry relative to BIM implementation challenges centres on answering many of the same data exchange, business process and policy phasing problems that have faced PLM deployment. Yet this is only part of the problem and despite the documented changes to AEC roles and responsibilities BIM implementation is driven by IT considerations. Instead practitioners should be driven by the requirements of the product design process and focus on implementing a unifying solution that enables information and processes to be to acquired, managed and utilised across various project and enterprise level systems. AEC practitioners may therefore see further changes to their newly emerging roles and responsibilities. As BIM maturity levels increase the common end point with PLM may be able to be realised with the construction industry moving towards rationalisation -including higher levels of consolidation and harmonisation in collaborative ways of working, increased use of IPD type procurement methods, and higher levels of collaborative process planning. From this perspective, the responsibilities that have emerged alongside PLM solutions (see Table 1); may begin to emerge in the construction industry and indeed if the value of BIM as a lifecycle management concept is to be realised, then these PLM responsibilities will eventually emerge.

Conclusions

This research provides an analysis of related literature on how PLM and BIM impact on the traditional activities of the manufacturing industries of the automotive and aerospace sectors and those of the construction sector. The influence of these activities relative to changes in roles and responsibilities of professionals, their relationships and scope of services within the project and organizational contexts were also reviewed. This comparison of the two concepts aims to provide better understanding into the changing nature of professional practice and may provide useful insights for evaluating PLM and BIM implementations relative to people and cultural change. There are only a few documented efforts of implementing PLM systems in the AEC companies [see [START_REF] Eastman | Integration of PLM solutions and BIM systems for the AEC industry[END_REF][START_REF] Pöllä | Skanska Finland: Improving cost control with Enovia V6. Dassault Systèmes[END_REF]. Previous research has also mapped PLM system functionality to existing and as yet unmet challenges facing BIM deployment [START_REF] Jupp | Incomplete BIM implementation: Challenges and role of product lifecycle management functions[END_REF]. From this perspective, the integration gaps relative to BIM technologies and information management have been demonstrated. However whilst PLM functionalities may be able to bridge a number of gaps in the construction sector's application of BIM, issues surrounding professional practice and cultural change are continuing to plague the adoption of these methods in both sectors. Consequently controlling the changes to practice identified in the literature are critical to transition processes and must be planned for with appropriate training, education, and management commitment. A useful direction for future research is to investigate how these industries are developing training, education, and management initiatives to support PLM and BIM deployment.

Table 1 .

 1 PLM -Changed Roles and New Responsibilities

	Role	Responsibility
	Project Manager	Direct implementation resources; Manage project schedules; Track Status;
		Resolve conflicts and issues
	Business Process	Provide project priorities and objectives; Direct participation of resources;
	Owner(s)	Resolve business process issues
	Subject Matter Experts	Communicate current process; Provide information details; Support user
		community during rollout
	IT System Support

Support site infrastructure; Extract legacy data; Provide technical expertise Solution Architect Analyze requirements; Configure application; Develop strategies for product lifecycle collaboration (including collaborative process planning) Technical Consultant Develop customizations; Provide technical expertise Service Owner Delivers and/or utilizes the expected business benefit, Manages service unit to deliver service benefits, Provides Subject Matter Experts to project

Table 2 .

 2 BIM -New Roles and Responsibilities

	Role	Responsibility
	BIM (Project) Manager Including developing a BIM management plan, understanding data exchange
		protocols, understanding model progression specifications and document
		management. Provide project priorities and objectives; Direct participation of
		resources; Resolve business process issues
	BIM Model Managers	Understanding data exchange protocols, Model auditing for model managers
	BIM Contract	Including new skills in the contractual implications of using 3D models as a
	Administrators	primary source of design information, administration and contract management
	BIM System Support	Support site infrastructure; Extract legacy data; Provide technical expertise
	Technical Consultant	Including technical skills relative to building information modelling concepts
		(functional basics) as well as functional software skills relative to project
		execution, software applications and model authoring
	Client/ Facility Manager Analyze operational requirements; specify requirements of as-built BIM model
		to be delivered for FM purposes.

Yokohama, Japan, 9 th -11 th July 2014