1 information island phenomenon
1 graph was drawn by German scholar Hannus, and was widely quoted in some related foreign documents to show the application history and development trend of information technology in the field of engineering construction. As can be seen from this figure, the application of information technology in the construction industry is mainly concentrated in three areas: architectural design, engineering design and construction. In the field of architectural design, 2D drawing software (2DCAD) appeared in 1980s, and 3D visual drawing software (3DCAD) appeared in 1990s. In the field of engineering design, structural analysis software appeared in the 1960s, finite element method, parametric design, engineering design and prefabricated modeling technology appeared in the 1970s, and various professional CAD software appeared in the 1980s. In the field of architecture, as early as 1960s, computers were used for statistical calculation and data management. Many engineering quantity calculation software and construction planning software appeared in 1980s, and production automation system appeared after 1990s. In addition, information technology is gradually applied in some fields, such as property management (FM) and product database. However, it must be pointed out that the development of all these computer software is only oriented to specific problems in specific fields in engineering construction, and people simply do not consider the needs of interdisciplinary information transmission and sharing from the perspective of the whole construction industry. Therefore, these computer softwares are usually one-sided and isolated, and it is difficult to exchange and integrate information effectively with each other. Because of this, the "islands" in the above picture are basically separated, that is, the so-called "IslandsofAutomation" or "IslandsofInformation".
At present, the phenomenon of "information island" has seriously restricted the full application and further development of information technology in the field of engineering construction, and more and more experts have begun to pay attention to information exchange and system integration in different application fields. Also in figure 1, we can see that various technologies or standards are trying to solve this problem partially or fundamentally. For example, the data model of International Interoperability Organization -IAI (Basic Industrial Classification), Internet technology, Electronic Data Interchange (EDI), Product Data Management (PDM) and CAD Data Interchange Format (DXF) and so on. In addition, Virtual Reality Modeling Language (VRML) has begun to enter and try to solve some related problems. We can also notice that "Polaris" in the upper right of the figure represents the development direction of information technology application in the future engineering construction field, such as multimedia technology, product data management system (PDMS), CoreModel (Coremodel, industrial basic classification (IFC), ISO product data exchange standard (STEP) and CAD data exchange format (STEP).
2 overall project system
Dr. T.Froese of the UniversityofBritishColumbia has made an in-depth study of the above-mentioned "information island" phenomenon, and put forward a complete framework of the relationship and development trend of various information technologies and standards. The "TotalProjectSystem" he proposed can fundamentally solve all kinds of information exchange and system integration problems, thus completely eliminating the so-called "information island" phenomenon. As shown in figure 2.
2. 1 3D CAD
At present, 2DCAD is mainly used in the field of architectural engineering design. But 3DCAD, as a perfect technology, has become the mainstream trend. One of the outstanding functions of 3DCAD is that it can use computer-based building models to design engineering projects and exchange information. This makes the traditional CAD model can contain and process more semantic information and non-spatial information, so the CAD entity is no longer just a general spatial shape, but a fairly clear building component. The development of 3D CAD promotes the research of product modeling. Building product model and data model standards (such as IFC) in the construction industry have become international research hotspots, but there are still many unresolved technical problems.
2.2 industrial engineering
In recent years, some advanced concepts of industrial engineering have been introduced into the construction industry, such as process reengineering, total quality management and lean construction. These new ideas all focus on improving the construction process without exception. In addition, project management software such as investment estimation and schedule planning must also participate in the project construction process. Therefore, attaching great importance to the construction process promotes the development of process modeling technology. The so-called process modeling refers to a series of technologies to express and use the information of building production process. The combination of product modeling technology and process modeling technology with new ideas of industrial engineering leads to the emergence of process design tools. The current schedule planning software is only a simple plan for the existing construction process. However, process design tools also involve all kinds of information of construction projects that are very important for integrating products and process models. For example, 4DCAD (spatial 3D+ time dimension), as a new process design and analysis tool, allows users to mine a large amount of construction project information and establish relationships, so as to design a more effective construction schedule. 2
2.3 Internet technology
The rise of the Internet in the 1990s has profoundly influenced the traditional information technology, especially the understanding and views on information technology. Accordingly, the way of sharing and exchanging information is obviously different from before. At present, the mainstream application of the Internet in the construction industry is only to communicate with people through email and enjoy documents through WWW. However, with the improvement of Internet distributed object architecture (such as CORBA) and general data exchange standards (such as XML), and the combination with data model standards, it will further promote the development of data exchange technology in the whole construction industry. All these technologies will enable all kinds of software in the field of construction engineering to achieve a higher level of integration.
2.4 The whole project system
The continuous development and mutual integration of these technologies will eventually form a highly integrated overall project system. The so-called overall project system should have three characteristics: ① comprehensiveness: it can provide corresponding application schemes for engineering management activities in different professional fields; ② Integration: All applications can enjoy all kinds of project information; ③ Flexibility: Various applications run in a highly modular, open and flexible distributed environment.
3 Information integration
In fig. 2, there is a dotted line that divides the whole picture into upper and lower parts. For the first half, we can understand it as integration based on information model, and the second half can be considered as integration based on Internet. The former attempts to take ISO product data exchange standard (STEP) or International Interoperability Alliance (IAI) Industrial Basic Classification (IFC) and other organizations as the unified standard of the whole construction industry, providing a basic framework for the development of software systems in different fields of engineering construction, so as to achieve a high degree of information integration between different software systems. Fig. 3 is an integrated information system based on an information model. This integration idea tries to solve the problem once and for all, but this method involves the foundation of the whole construction industry and requires the cooperation of national and even international forces, which cannot be solved by individuals or enterprises. The number1(the latest version of1998) cited in this paper emphasizes the development of various information models, and holds that with the application of the unified building product model (the coastline in the figure) around 20 10, all "information islands" can be finally connected. However, it is worth remembering that 1987 ~ 1996 version of the map (/#/? source=bdzd