Computer Aided Drafting, Design and Manufacturing Volume 26, Number 1, March 2016, Page 58 CADDM

A mobile application framework of the BIM-based facility management system under the cross-platform structure

Xiao Yaqi1, Hu Zhenzhong1, Wang Wei 2, Chen Xiangxiang3

1. Department of Civil Engineering, Tsinghua University, Beijing, 100084, China; 2. Metro Corporation, Guangzhou, 510000, China; 3. Shenzhen BStar Technology Co., Ltd, Shenzhen, 518055, China.

Abstract: The building information model/modeling (BIM) technology is currently applied in a broad range of applications and research for facility management, while the BIM-based mobile FM is difficult owing to various factors and environments. For example, the mobile applications usually require frequent cross-equipment compatibility. This paper proposes a reasonable BIM-based FM cross-platform framework and develops a mobile application on the basis of an existing BIM-based FM system. The developed mobile application is applied in a case study of a metro station project in Guangzhou to verify its effectiveness in FM practice. It helps maintenance staff in viewing BIMs, accessing related information, and updating maintenance records in a unique platform. The test results demonstrate that the proposed BIM-based cross-platform framework meet the FM application requirements and supports the extension of FM functions. Key words: facility management; building information model/modeling; mobile application; cross-platform; hybrid application

during a building life cycle. The BIM concept derives 1 Introduction from the penetration of the IT revolution in the Facility management (FM) is always an important construction industry. By applying BIM to the task within the construction life cycle process because construction field, a highly effective integrated of its long time span and huge related information. information platform can be provided to solve the [2] Previous research [1] indicated that, the cost associated interdependence of multiple subjects . The with O&M could take up to 60% of the total cost of a BIM-based application can generate and manage project. Currently, inefficient and sometimes building data during a building life cycle at the FM [3] error-prone manual works are the common practice in stage , which is the last step in the construction FM. Therefore, an effective FM tool can improve the industry and is an indispensable part. The use of BIM management process and save both time and cost. technology to the FM in construction promotes Furthermore, when proceeding the operation and information sharing within building lifecycle. It also maintenance activities, the staff usually has to search increases the accuracy of information, thereby information such as specifications, checklists, providing maintenance staff a convenient management maintenance reports, and maintenance records in a platform. Moreover, it facilitates the centralized large amount of as-built documents. These documents management of the geometry information of including paper files and drawings are too fragmentary, components and equipment, attribute information, and resulting in the unsatisfactory for the overall FM and monitoring information and improves the efficiency of [4] high professionalism for every maintenance staff. management in FM . The building information model/modeling (BIM) The BIM technology enhances the cooperation, technology has provided a new solution to share information integration and visualized expression to project design information. BIM can be regarded as fundamentally solve the problem of low efficiency in the process of generating and managing building data the traditional construction industry caused by

Project item: Supported by the National High-tech Research and Development Program of China (2013AA041307), the National Natural Science Foundation of China (51478249) and the Tsinghua University-Glodon Joint Research Centre for Building Information Model. Corresponding author: Hu Zhenzhong, Male, Ph.D., Associate professor, E-mail: [email protected]. Xiao Yaqi et al., A mobile application framework of the BIM-based facility management system under the… 59 fragmentary information. However, the development frameworks, including safety and structure monitoring, of BIM technology still faces various problems, one of facility management, and simulated optimization of which is the urgent need to solve the limit of BIM airports, and others, which have been applied to platform application onsite because current BIM bridges or other infrastructure[9]. Another research has systems under broad research and applications are utilized BIM technology to integrate safety mainly deployed at the PC terminal. Technical information on the construction life cycle and studied personnel on the construction and maintenance sites the safety management framework at the BIM-based can hardly obtain and upload data and information maintenance management[10]. These studies have using these BIM systems. Therefore, the extended contributed to the promotion and application of BIM. application of BIM system to mobile terminals is Combining BIM technology with various new imperative. However, the problem faced by the technologies can extend the scope of application of development of mobile application programs is the BIM technology and perfect the use functions of the requirement for more frequent cross-equipment BIM system. Combining BIM technology with compatibility. On the other hand, short cycle, low cost, construction automation technology to complete the and easy maintenance of apps have attracted more integration of monitoring information across various attention from development teams, which in turn subsystems and therefore realize the management of benefit the rapid development of cross-platform the life cycle of intelligent construction is a research technologies in the last few years. direction with high potential[11]. Currently, RFID This study first studied and compared several (Radio Frequency Identification) and 2D barcode cross-platform development technologies to mobile technology are broadly applied to data acquisition, development in the BIM-based FM system, then a such as component identification, positioning of structural design of the cross-platform development of personnel indoors, and so on. Krukowski and mobile applications based on an existing BIM-based Arsenijevic[12] have discussed man and machine FM system was proposed. A prototype was developed positioning technology based on RFID. Lin et al.[13] based on the cross-platform structure to achieve combined BIM technology with 2D barcode relevant functions in a case study. technology and used mobile equipment to scan 2D barcodes to obtain the BIM model and relevant 2 Summary of relevant research attribute information. This has increased the efficiency of FM and has been successfully applied in an office The problems that beset the traditional FM in the building construction project. In addition, the construction industry consist of low efficiency and combination of BIM technology with Geographic waste of resources, the major cause of which is gap in Information System (GIS), Internet of Things (IoT), data capture and entry. The advantage of applying and cloud technology is also a current research hotspot. BIM technology in FM is its capacity to integrate data Chen and Ding[14]studied the design of operation and and information on the design and construction stages maintenance control platforms of city lifelines based and effective promotion of teamwork among all the on IoT and BIM. participants. It also makes the maintenance management of facilities more scientific, reasonable, and orderly[5]. Becerik-Gerber proposed a 3 Exploration of cross-platform development pyramid-shaped data structure and emphasized the technology [6] responsibility of all the participants to provide data . 3.1 Comparative analysis of the cross-platform However, the effect of applying the current BIM solution technology at the FM is too fragmentary, and the realization of information integration and full Currently, most applications that operate at the management for BIM-based FM still need to be mobile terminal are native applications, and the strengthened[7]. Although a few cases of BIM programming language used in operating systems on application realization exist in the life cycle of the mobile computation platforms is determined by construction at this stage, research shows that the operating systems. To most operating systems, it long-term consideration of the scope of BIM provides a native development language (e.g., iOS application in a construction project is likely to result system supporting Objective-C, Android supporting in more benefits[8]. To explore the application of the Java language, and Windows Phone system supporting BIM life cycle in projects, some scholars have studied C# language), and it is considered the most suitable the entire framework of BIM application. For for the development work on this platform. Although instance, Terreno S. proposed three typical research another language can possibly be used, some 60 Computer Aided Drafting, Design and Manufacturing (CADDM), Vol.26, No.1, Mar. 2016 weaknesses and restrictions still exist. In addition to direct interaction with the system native UI through the difference in languages, the SDK and cases for communication with the bottom API of the system. It developing application programs differ according to also guarantees the high performance and UI platforms. Although the functions of the equipment smoothness of the application. The largest problem of are almost the same, such as geographic positioning, this solution is the insufficiency of materials and high cameras, access contact, and offline storage, the APIs cost of development. for access to these function differs in every 3.1.3 C++ cross-platform development platform[15]. Currently, Android, iOS and Windows Phone have Software directly operates on the operating system. provided C++ support in development, thus the direct Native applications can completely utilize the API and use of C++ to realize the non-interface part can platform characteristics of terminal operating systems guarantee performance and also share codes. When and are characterized by strong development ability, C++ is used to realize the interface part, it is easy to good interactivity, and high efficiency. However, with adopt the supersets Objective-C++ and C++/CX of the fast development of application programs, the C++ under iOS and Windows Phone, respectively. market has driven the demand for the faster release of However, applying C++ under Android is difficult products, and mobile application programs today because most of the interfaces are realized in Java. require frequent cross-equipment compatibility. Given Two solutions currently exist: The Java method the weaknesses of long development cycle and the provided by the JNI call system and the independently high cost raised by separate development of different designed UI of OpenGL. Comparatively, the cost is operating systems, many third-party cross-platform not so high if the interface for every platform is development technologies have emerged accordingly. separately designed because good official support is Some mainstream cross-platform solutions are provided under all platforms and relevant tools and discussed below. files are complete. Thus, the interface design with 3.1.1 Mobile web hybrid application development C++ is not the best choice in many circumstances. The hybrid application of the cross-platform call of 3.2 Comparative analysis of hybrid development the terminal hardware is realized through the system technology frameworks API of the JavaScript call self-package or third-party With regard to the mobile application based on add-on plug-in package. In addition, hybrid programs, BIM, the browsing of 3D models is an important including HTML, CSS, JavaScript, and system API function. A comparison of the above-mentioned package, are deployed at the sides of the terminal. The cross-platform technologies shows that it is more UI exhibition of the application and its dynamic reasonable to adopt C++ to realize the 3D graphic transition effect are realized through the analysis of engine of the non-interface part, given that the the Webkit kernel to construct the mobile application relevant technologies are quite mature. The business UI similar to Web applications. The specific logic of BIM application and the realization of UI first frameworks include Phonegap, Sencha Touch, and consider mobile web hybrid development technology. Titanium. The advantage of this solution lies in its low With the advantages of short development cycle and cost, short cycle, and easy use, but its efficiency is low cost, it can call the local APIs to satisfy the needs lower than that of native applications, particularly in of BIM operation and maintenance management (such 3D performance. as completing component identification through 2D 3.1.2 Xamarin cross-platform development barcode scanning with cameras). Given that the hybrid application itself is based on web development Xamarin supports the application development of technology, it can better support access to Android and iOS using C#, and it has evolved from maintenance database through Internet technology to Mono. In an iOS environment, it is compiled into a realize the share of data and information at the PC binary document by AOT and is realized through the terminal. built-in Mono virtual machine on the Android system. With regard to UI, it can use the system built-in Currently, the major hybrid application interface components through the call system API or technologies are Phonegap, Titanium, Sencha, and [16] develop cross-platform UI with low-requirement AppCan . Table 1 summarizes and compares the customization based on Xamarin. Forms. Compared frameworks of these four technologies. with PhoneGap based on HTML/JS/CSS, the Given that many functions related to the significant advantage of Xamarin is its capacity for development of a BIM application require plug-in Xiao Yaqi et al., A mobile application framework of the BIM-based facility management system under the… 61 extension (including 3D graph engine, camera, etc.), structure, Phonegap is suitable for the cross-platform UI design and user experience can be minimized hybrid development structure. The BIM-based considerably. In the comprehensive consideration of Phonegap mobile application framework is illustrated the compatibility of the system and the weight of the in the following diagram.

Table 1 Comparative analysis of hybrid development technology frameworks. Hybrid Good Lightweight Open Beautiful UI sufficiency of Easy plug-in frameworks compatibility framework source design development materials PhoneGap √ √ √ - √ √ Titanium - √ √ √ √ - Sencha - - √ √ √ - Appcan √ - - √ - -

The core of using Phonegap to develop BIM-based custom developed plug-in, such as the 3D graph engine. hybrid applications is the relevant web technology, The custom plug-in is developed and packaged using including Html5, javascript, and CSS. It uses the model the corresponding languages according to different view controller (MVC) framework to construct apps, platforms, and it provides a Javascript interface for the and the supporting operating systems include the call of the main program under the Phonegap mainstream operating platforms including Android, iOS, framework. In addition, this application has access to and Windows Phone. Fig.1 illustrates the framework of the operation and maintenance database through mobile Phonegap mobile applications. Html5 and CSS are Internet or Wifi to realize the sharing of information mainly used for UI design, while the core functions of with the PC terminal. The entire application app include database access and call plug-in, which can performance is mainly limited by two factors: the UI of be realized through javascript. Considering the web technology development and business logic are functional needs of BIM application, the plug-in limited by the WebView functions that can be provided concerned can be classified into two categories. The by various platforms; and the plug-in performance first one is the plug-in packaged under the PhoneGap related to the development of various platforms is framework, including the camera. The other one is the limited by the abilities of various operating platforms.

Fig. 1 Architecture of Phonegap mobile applications.

According to the above-mentioned studies, this the Ionic icon database is used, and the JavaScript study selects Phonegap as the hybrid cross-platform framework provides the mobile Web application app framework and use of Ionic for both UI and development framework. Ionic is based on the business logic design. AngularJS is mainly used as the AngularJS basic framework development and basis to create the UI database of lightweight mobile naturally follows the restriction of the said framework. phones, which are characterized by fast speed, modern In addition, CLI is used to simplify the development interface, and good appearance. Ionic has three main of application, structure, and simulation operation. parts. The CSS framework provides native app The ionic CLI uses Cordova and depends on the textured CSS simulation. In the realization of ionic, platform SDK (Android and iOS) to realize the 62 Computer Aided Drafting, Design and Manufacturing (CADDM), Vol.26, No.1, Mar. 2016 packaging of mobile web projects into native app. management and technical staff who are experienced in facility maintenance management. The feasibility of 4 System implementation and a case study function needs should also be assessed by combining the fast-growing information processing technology, Based on the selected framework, an FM system computer-aided design, and BIM technology, to named BIM-FIM[17] was developed for BIM-based conduct specific research and development. The 3D lifecycle platform application framework. The graphic platform is an indispensable part to satisfy the BIM-FIM consists of the five main functions, i.e., basic demand of BIM application. The core layer of electronic integrated delivery of the as-built BIM, the platform in Fig.2 includes the application layer, equipment information management, emergency 3D graph engine developed with C++, shared codes management, document management, maintenance under various mobile platforms, and various platform and repair management. The document management is interfaces separately developed using correspondent combined with the Construction Project Filing languages. The graph platform is then customized as Procedures GB/T 50328-2014 and is deeply integrated independent plug-ins according to the operating with the BIM system. By establishing the net-shape systems, and under the phonegap framework. The correlation between files and BIMs, it allows users to JavaScript call plug-in is used to realize the quickly search the files associated with the changeover between the application interface and components (equipment) and the components graph platform. The 2D barcode scanning function (equipment) associated with the files, thereby greatly related to the function of component identification is a increasing the value of application for BIM models plug-in packaged by the framework, and the direct call and files. On the basis of BIM-FIM platform, this can realize relevant functions. In addition, this study further achieves the design and development of application realizes component (equipment) the mobile application for FM. identification through 2D barcode scanning and uses 4.1 Function description the Internet to access the maintenance database to The design and perfection of application functions realize the real-time sharing and mobile management require the systematic investigation of the of operation and maintenance information.

Fig. 2 Architecture of the 3D graphic platform.

4.2 Cross-platform framework The application layer refers to various specific function modules, and the surface layer provides a Fig.3 depicts the logic framework of the BIM-FIM user-friendly human-machine interaction interface for mobile application. Six layers are designed for the all the application functions. framework, namely, data layer, model layer, system layer, platform layer, application layer and surface 4.3 A case study layer. The data layer provides a BIM maintenance Guangzhou Transit Project is a parcel of the repository, as well as some data interface and municipal engineering in Guangzhou. The prototype algorithms for data conversion and integration. It also system was applied to a part of manages all of the users and authorities. The model which would be put into operation later, the total layer extracts the proposed FM model from the data length of which is 11.7 km from Xilang Station to layer for the system layer, which consist of the Yangang Station, opened to the public in corresponding application for different mobile December 2015. Fig.4 illustrates the operation operation system. The platform layer forms the effect of BIM-based FM in mobile phones with the environment for 3D graphic engine, as well as for FM. basic functions applied on the Android system. The Xiao Yaqi et al., A mobile application framework of the BIM-based facility management system under the… 63 application was implemented on HUAWEI P7 with can also support iPhone because of cross-platform quad-core processor (1.8 GHz) and 2GB RAM. It development.

Fig. 3 Logic framework of the BIM-FIM mobile application.

Fig. 4 Operation effect of the BIM-FIM mobile application.

The BIM-FIM mobile application provides Before the FM work began, the unique ID for every functions including component identification, BIM important facility or equipment was inputted into the browsing, modification and submission of BIM-FIM database for quick search. Each facility was maintenance logs, search of facility data, and tagged by barcodes for identification. During the FM management of drawings. The application of the process, the maintenance staff could check the facility mobile 3D graphic platform and FM platform list from Internet-connected mobile device and select improves the efficiency and quality of the delivery of relevant BIM objects. 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Xiao Yaqi is currently a Master Wang Wei is currently a senior student in the Department of Civil engineer and working in Guangzhou Engineering, Tsinghua University. His Metro Corporation. He also serves as a research focues on development and leader of a research team focusing on application of BIM. He can be reached the application in metro engineering of by [email protected]. BIM. He can be reached by [email protected]. Hu Zhenzhong is currently an associate professor in the Department Chen Xiangxiang is currently the of Civil Engineering, Tsinghua founder and CTO of Shenzhen BStar University. He received his bachelor Technology Co., Ltd. He received his and doctor degree from Tsinghua bachelor and master degree from University, in 2005 and 2009 Tsinghua University, in 2012 and respectivly. His research interests include BIM and 2015 respectively. His research digital technology for disaster prevention. He can be interests include BIM and facility reached by [email protected]. management system. He can be reached by [email protected].