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Enhancing the ifcOWL ontology with an alternative representation for geometric data

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Abstract

Over the past few years, several suggestions have been made of how to convert an EXPRESS schema into an OWL ontology. The conversion from EXPRESS to OWL is of particular use to the architectural design and construction industry, because one of the key data models in this domain, namely the Industry Foundation Classes (IFC), is represented using the EXPRESS information modelling language. These conversion efforts have by now resulted in a recommended ifcOWL ontology that stays semantically close to the EXPRESS schema. Two major improvements could be made in addition to this ifcOWL basis. First, the ontology could be split into diverse modules, making it easier to use subsets of the entire ontology. Second, geometric aggregated data (e.g. lists of coordinates) could be serialised into alternative, less complex semantic structures. The purpose of both improvements is to make ifcOWL data smaller in size and complexity. In this article, we focus entirely on the second topic, namely the optimization of geometric data in the semantic representation. We outline and discuss the diverse available options in optimizing the data representations used. We quantify the impact of these measures on the ifcOWL ontology and instance model size. We conclude with an explicit recommendation and give an indication of how this recommendation might be implemented in combination with the already available ifcOWL ontology.

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... OntoSTEP allows for users to restrict the translation to instances representing the Bill of Materials (BOM) which consists of four STEP entities (product, product_definition, product_definition_formation, and product_definition_relationship). Furthermore, when translating the geometric data into OWL, the output file becomes quite large leading to performance issues as pointed out by Pauwels et al. [20]. Supporting simplified geometry representations would alleviate the problem. ...
... Translating geometric data from P21-to-OWL can lead to overly large output files due to aggregated data types such as lists of coordinates [21]. Reducing file size is possible by generating less complex KGs for geometry without the loss of information [20]. To this end, we adopted one of the alternative representations of geometric data presented in Pauwels et al. [20]. ...
... Reducing file size is possible by generating less complex KGs for geometry without the loss of information [20]. To this end, we adopted one of the alternative representations of geometric data presented in Pauwels et al. [20]. This approach leverages data properties for coordinate information. ...
Article
OntoSTEP is a method to translate the STandard for the Exchange of Product model data (STEP) schema and its instances to an ontology and knowledge graphs represented in the Web Ontology Language (OWL). OntoSTEP models can be integrated with any OWL models to enrich their semantics. However, the current implementation has several limitations , mainly in (1) supporting the latest ISO 10303 schemas and (2) generating various representation types depending on the purpose of use. We present an improved implementation of OntoSTEP to overcome these limitations. In this paper , we demonstrate that the new implementation can successfully translate STEP schemas and instances in a faster and more flexible way, thus furthering the adoption of the full capabilities of ISO 10303. By encoding STEP entities in OWL, we facilitate integration with other standards through knowledge graphs.
... Unfortunately, the ifcOWL is strictly following the EXPRESS schema of IFC in order to allow bidirectional conversion, thus causing an overhead within the ontology and RDF file, because complex and nested relations in IFC are not simplified by means which ontologies provide [24]. The resulting ontology is therefore complex and aims to capture the entire building data within one schema. ...
... Capturing the geometric representation of buildings and their entities in a (Semantic) Web context still remains a challenge and field of research [24]. With the inability of ontologies to describe ordered lists in simple and straightforward manners, the description of simplified, tessellated geometry proves to be inefficient. ...
... In [38], initial mappings have also been explored with ifcOWL, by creating a new relationship geo:hasGeometry for IfcSite to represent the longitude and latitude as a WKT point, building on the analysis and recommendation made by [24]. More recent work has looked into converting IFC elements, e.g., IfcWallStandardCase directly into 2D geospatial data. ...
Article
Geometric data plays a central role in the geospatial domain, architectural design and construction industry. For upcoming, new approaches to store building data, such as the Semantic Web, no universal common agreement exists on the combination of geometric and non-geometric data. It can therefore be unclear to users on how to represent their geometries, leading to a decelerated application and advancement of making building data available over the web. This gap can only be bridged if a common approach on the representation of geometries on the web is achieved. To first generate a common understanding of geometry representations, an overview of existing and developing geometry (web) standards needs to be given and discussed, i.e., the Industry Foundation Classes (IFC), CityGML, GeoSPARQL, and the OntoBREP and GEOM ontologies. This discussion needs to consider general contexts, e.g., 2D, 3D, detailed, or tessellated geometries, and specific use cases of the construction industry. Based on these discussions, this paper aims to propose a general recommendation for web-based geometry representations to enhance future applications of building data on the web. Due to the variety of use cases and their requirements, as well as technical constraints based on deviant interpretations of geometry descriptions from different geometry kernels, it became clear, that no approach or standard is generally superior to others. The biggest distinction identified in this paper is posed between the context of visualizing, where simplified, tessellated geometry holds the highest advantage, and (parametric) modeling, which requires semantically detailed geometry representations. Hence, we recommend to interlink non-geometric data with multiple geometry representations, to address all relevant contexts and use cases appropriately. The individual geometry representations should be chosen based on the relevant use cases for an optimal experience when using and exchanging geometry on the web. With this recommendation, the benefits of all discussed approaches can be exploited while avoiding their respective challenges.
... (Quattrini et al., 2017b) (Cursi et al., 2015) The IfcOWL project converts EXPRESS/IFC schemas to ontology. This project is currently embraced by buildingSMART as a future development of the IFC standard (Pauwels et al., 2017). ...
... HBIM model is integrated with such ontology semantic relational system to enhance the representation of heritage knowledge and semantic reasoning. The current IfcOWL project converts EXPRESS/IFC schemas to ontology, which has been embraced by buildingSMART as future development of the IFC standard (Pauwels et al., 2017). The obtained BIM model can be straightforwardly converted to ontology OWL format and integrated with ...
... The integration can be a two-step modelling process by migrating IFC files to ontology environment for semantics richness (Quattrini et al., 2017a;Pauwels et al., 2017). ...
Thesis
Heritage Building Information Modelling (HBIM) is a major issue in heritage documentation and conservation. The obtained HBIM model provides a parametric and semantic description of the heritage elements. This thesis presents methods for the generation of HBIM models from point clouds (obtained by photogrammetry or laser scanning), surface mesh and solid geometry. A concept of solid/mesh-to-HBIM is proposed using Autodesk Dynamo visual programming, which transfers the parametric “Family” and geometric structures to parametric and semantic HBIM models. The parametric HBIM modelling process involves conventional manual parametric “Family” creation and semi-automated building reconstruction by Dynamo. The semantic HBIM modelling process directly transfers the segmented solid geometry and closed mesh-to-BIM environment. The segmented elements can be stored and managed in the BIM environment with attached attributes information and relationships established among the elements.
... Geometry descriptions in a Semantic Web context are -due to the inefficiency of the Semantic Web when handling ordered lists (see Section 2.1.4) -a highly discussed and questioned topic [40,83,111]. In addition, the requirements to geometry descriptions in a Semantic Web context are higher than for common geometry formats, as several dedicated non-RDF data formats exist that are optimised for individual use cases (e.g. ...
... Since geometry descriptions heavily rely on ordered lists (e.g. polylines), describing geometries in RDF is deemed to be inefficient [111] and only few geometry schemes exist, see Section 3.2.2. Some of the considered geometry ontologies provide individual linking methods between non-geometric and geometric descriptions, e.g. ...
... Since the idea to store geometry in simpler forms than RDF graphs in a Semantic Web context is well discussed [83,111], several implementations for linking to geometry descriptions that are embedded in RDF literals are available. Some of the implementations are based on the translation of a broad schema into RDF and thereby rely on the original schema's geometry description, i.e. an OWL version of CityGML expects geometry descriptions to be stored in RDF literals following the GML schema [125]. ...
... The current IFC specification has EXPRESS long-form schema, XSD schema, and underdevelopment ifcOWL schema. The instance data format for these schemas is IFC step physical file (SPF), XML file, and RDF file respectively (Pauwels et al. 2017). Although there is on-going development in ifcOWL to represent AEC data in RDF graphs for future trends such as semantic web and linked data, most current BIM data or vendors still utilize IFC-SPF and XML. ...
... It helps to achieve the ultimate goal of interoperability and information exchange, which is the common goal for IFC. Although there may be a little more groundwork required when first setting up a semantic database, there is some existing/ on-going work related to bringing IFC into the semantic web world (Pauwels et al. 2015b(Pauwels et al. , 2017Pauwels and Terkaj 2016). ...
... In this way, these applications have a larger potential to grow into the public usable, trustworthy and helpful tools (Pauwels and Terkaj 2016); vi) Ontology can be divided into several modules, making it easier to use a subset of the entire ontology; vii) Geometric aggregated data (e.g. lists of coordinates) can be serialized into alternative, less complex semantic structures; viii) ifcOWL data will have smaller in size and complexity (Pauwels et al. 2017). ...
Conference Paper
Modern data models are evolving. Modern data models like resource description framework (RDF) and JavaScript object notation (JSON) show advantages in cross-domain knowledge sharing, ease in reuse and extension, faster and higher computational capability, and human readability. Industry foundation class (IFC) dominates the architecture engineering and construction (AEC) industry as open BIM standardized data model to store and exchange information. However, IFC has the limitation on both schema level and instance data level such as lack of entities and attributes, difficulties in direct queries, lack of manipulating tools, and cross-domain data linking. Combination use of both modern data standards and IFC can bring potential applications. The trend to migrate AEC data into more advanced modern data models is unstoppable. The objective of this paper is to analyze existing AEC data standards and propose a conceptual framework using both modern data standards like JSON and RDF with traditional IFC as a foundation for different building automation system (BAS) use cases. This paper first examines the current limitation of IFC data model and analyzes the capabilities, impact, challenge, and opportunities of more contemporary data models to host AEC data. A conceptual framework utilizing both modern data models and IFC for BAS use cases is proposed to demonstrate the benefits and potential in integrating IFC and modern data models for various applications.
... Also quite recently, Pauwels et al. [19] discuss how the current geometry representation within the ifcOWL ontology could be enhanced. Within their publication, different approaches to represent geometry in RDF graphs are discussed. ...
... The standardised GeoSPARQL extension is implemented in several RDF triplestores compared to the spatio-temporal querying extension stSPARQL that is applied in a limited amount of triplestores. GeoSPARQL and stSPARQL require 2D WKT or GML descriptions in RDF literals, while 19 https://w3id.org/bot# 20 https://w3id.org/omg# ...
... Since geometry descriptions heavily rely on ordered lists (e.g. polylines), describing geometries in RDF is deemed to be inefficient [19] and only few geometry schemes exist. The schemes shown in this publication are 3DMO [41], which is initially designed for annotation, OntoBREP [31], OntoSTEP [65], GEOM [30,66], and ifcOWL [19,67]. ...
Article
The exchange of construction-related data over the Web via Semantic Web Technologies is gaining interest in current research. However, most research focuses on non-geometric data, neglecting the description of geometry. While several methods to include geometry descriptions into a Semantic Web context exist, no uniform approach or general recommendation exists for the endeavour of describing building components in their entirety – including geometric descriptions –, leading to an increased suspension in applying Semantic Web Technologies in the construction domain. To therefore ease the description of geometric data in a Semantic Web context, we conduct an extensive literature review and analyse the identified, oftentimes isolated implementations for geometry descriptions in that context, with focus on requirements set by domain-specific use cases. Based on this analysis, we group the currently available implementations into approaches and compare them to offer means for deciding on which approach or implementation suits individual use cases. The identified approaches vary in their depth of the geometry description's integration into the Semantic Web and are subsequently studied regarding their overall aptness and characteristics in consideration of their application for future industry and research projects. In respect of the ongoing research in the field of the application of Semantic Web Technologies, not only in the construction domain, this article poses as an important foundation by giving a clear overview of existing implementations and relevant open research questions. Having this overview, the suspense for adapting to Semantic Web methods for describing geometries can be overcome by users more easily, while software developers can start to connect their clients' use cases to suitable approaches and related implementations to represent geometry in a Semantic Web context.
... Time-series databases in general can be characterized as large streams of ordered data points (lists). It has been shown that ordered lists in general do not fit very well in an RDF graph structure [42,43]. Yet, several researchers nevertheless insist on storing such sensor readings in RDF graph structures. ...
... Cartesian points, polylines, bidirectionally curved surfaces, etc.). Storage of such ordered lists in a knowledge graph as linked data is often inefficient, similar to what was concluded for the representation of sensor data streams in RDF (see [42,43] for much more detail). ...
... The OWL version of the IFC ontology [17,54] obviously follows the exact same structure. This also includes all 3D Fig. 9 Core structure for IFC building topology, ending on the right with inheritance trees for IfcProduct geometry, using a 'linked list' pattern for representing all lists of values [17,43] (see Cartesianpoint, Polyline, etc., in Sect. 2.3). ...
Chapter
The built environment in the Industry 4.0 is digitizing rapidly and producing great amounts of data. These data are of different kinds and follow specific structures and logics, depending on what they are used for and where they come from. This includes vendor-neutral and exchangeable files, such as the Industry Foundation Classes (IFC), that capture building and infrastructure data in neutral and exchangeable files; knowledge graphs and linked data that store building data in web-based graph databases; time-series databases that store sensor data values (big data; data lakes); diverse standard file formats to represent 2D and 3D geometry; and property servers as well as product databases. This chapter will particularly investigate knowledge graphs and linked data. These data technologies promise to represent any data on the web and link them all together. This chapter will explain the most basic parts of the technology, while omitting technical detail. It gives an overview of how these technologies are used in the AEC and smart buildings domains. The chapter ends with a discussion on applicability and limitations of the documented technologies and an outlook into the future.
... These possible advantages have encouraged several researchers to implement a set of more or less functional IFC-OWL conversions, despite the fact that IFC has a rather complicated and compressed structure. One of these implementations is ifcOWL [3,[7][8][9][10][11][12]. This ontology maintains the strong structure of the original EXPRESS version [13], although some expressiveness is lost with the conversion [14] due to certain problems, such as the conversion of list data types. ...
... These building views contain the necessary and sufficient information needed to properly execute a building process. Pauwels et al. [8] propose an improvement of the ifcOWL ontology through an alternative representation for geometric data. This representation relies on the inclusion of a WKT (Well-Known Text) serialization. ...
... To simplify the management of the ontology, we followed a strategy similar to that posed in [8], in particular in terms of the Cartesian coordinates and rotation angles in the relative direction of the axes. As mentioned above, the ifcOWL ontology makes use of an intricate system based on RDF lists. ...
Article
Full-text available
This paper presents an indoor navigation support system based on the Building Information Models (BIM) paradigm. Although BIM is initially defined for the Architecture, Engineering and Construction/Facility Management (AEC/FM) industry, the authors believe that it can provide added value in this context. To this end, the authors will focus on the Industry Foundation Classes (IFC) standard for the formal representation of BIM. The approach followed in this paper will be based on the ifcOWL ontology, which translates the IFC schemas into Ontology Web Language (OWL). Several modifications of this ontology have been proposed, consisting of the inclusion of new items, SWRL rules and SQWRL searches. This way of expressing the elements of a building can be used to code information that is very useful for navigation, such as the location of elements related to the actions desired by the user. It is important to note that this design is intended to be used as a complement to other well-known tools and techniques for indoor navigation. The proposed modifications have been successfully tested in a variety of simulated and real scenarios. The main limitation of the proposal is the immense amount of information contained in the ifcOWL ontology, which causes difficulties involving its processing and the time necessary to perform operations on it. Those elements that are considered important have been selected, removing those that seem secondary to navigation. This procedure will result in a significant reduction in the storage and semantic processing of the information. Thus, for a system with 1000 individuals (in the ontological sense), the processing time is about 90 s. The authors regard this time as acceptable, since in most cases the tasks involved can be considered part of the system initialization, meaning they will only be executed once at the beginning of the process.
... Métral [24] (Figure 3) provides interoperability between the minimal model, IFC and CityGML using ontologies like ifcOWL [27] and for CityGML [28]. As an example for the detailed description of these subclasses, the representation of linear aggregated objects, mainly used to represent utility networks, can be found in Appendix B, Figure A2. ...
... Métral [24] (Figure 3) provides interoperability between the minimal model, IFC and CityGML using ontologies like ifcOWL [27] and for CityGML [28]. Local and national codes (e.g., [29][30][31][32]) are integrated to describe spatial relations among objects. ...
Article
Full-text available
This paper addresses the issue of offering a consistent 3D visual rendering of subsurface objects when databases face non-completion. Digital modelling of subsurface objects, like utility lines, underground buildings or tree roots, is a difficult task. Data available are incomplete and not precise. The in situ acquisition of existing objects to increase data quality is complex and, therefore, costly. In this paper, a methodology to obtain missing spatial and geometrical data through field or empirical means is proposed. In addition, confidence levels are assigned to existing and derived spatial and geometrical attributes. They are consolidated on a class level and visualized through a bounding shape, called secondary object.
... Since the introduction of ifcOWL by Beetz et al. in 2009(Beetz, Leeuwen, & Vries, 2009), a number of criticisms and enhancements have been proposed ( (Pauwels, Krijnen, Terkaj, & Beetz, 2017) and (Beetz, Leeuwen, & Vries, 2009)). First, ifcOWL does not comply with many of the principles presented in Table 1. ...
... Restructuring of ifcOWL using BFO was conducted on the basis of the prior work reported in (Beetz, Leeuwen, & Vries, 2009), (Terkaj & Pauwels, 2016), (Sojić & Terkaj, 2015), (Pauwels, Krijnen, Terkaj, & Beetz, 2017), (Pauwels & Terkaj, A Method to generate a Modular ifcOWL Ontology, 2017) and (Roxin & Pauwels, 2016). We believe that an improvement of the underlying ifcOWL structure, and of its ability to promote interoperability, is essential to provide more semantic enrichment and accuracy of the ontologies. ...
Article
Building Information Modelling (BIM) is a process for managing construction project information in such a way as to provide a basis for enhanced decision-making and for collaboration in a construction supply chain. One impediment to the uptake of BIM is the limited interoperability of different BIM systems. To overcome this problem, a set of Industry Foundation Classes (IFC) has been proposed as a standard for the construction industry. Building on IFC, the ifcOWL ontology was developed in order to facilitate representation of building data in a consistent fashion across the Web by using the Web Ontology Language (OWL). This study presents a critical analysis of the ifcOWL ontology and of the associated interoperability issues. It shows how these issues can be resolved by using Basic Formal Ontology (ISO/IEC 21838-2) as top-level architecture. A set of competency questions is used as the basis for comparison of the original ifcOWL with the enhanced ontology, and the latter is used to align with a second ontology – the ontology for building intelligent environments (DOGONT) – in order to demonstrate the added value derived from BFO by showing how querying the enhanced ifcOWL yields useful additional information.
... An increasing amount of building data is being published as RDF graphs and AEC industry-specific ontologies are being developed [10]. The benefits of structuring building data using semantic web technologies are the improved interoperability, linking across domains, and additional logical inference and proofs [11] which coincide with many of the ambitions of the building industry such as lossless information exchange and complete interoperability. By defining ontologies and data definitions for different disciplines within the AEC sector, a connected and comprehensively legible interdisciplinary practice becomes possible. ...
... More promising alternatives are web-based applications such as BIMserver. 11 These allow to upload and visualise BIM models inside a web browser and are open source. BIMserver in particular enables users to open up their own BIM server for file sharing. ...
Chapter
Over the last years, Building Information Modelling (BIM) has been increasingly adopted in building projects for its benefits to collaboration and associated risk mitigation. Recent work is trying to make this data available over the web (web-based BIM applications). Most notable in making building data web-ready is the linked building data (LBD) initiative. This group has worked on a number of vocabularies and ontologies, thereby starting from a linked data approach (RDF graphs), aiming at representing building data on the web. Yet, a platform is needed that allows to manage the available linked building data, including 3D geometric visualisation, which is the topic of this article: a LBD server. The LBD server is a web-based application which allows users to upload building data and visualise their geometric representation in a graphical user interface, thereby also enabling to link to this data.
... This fixed length requirement has implications for variable length strings and aggregates, such as EXPRESS LISTS, used extensively in geometry definitions [18], that are stored in the HDF5 heap structure. As opposed to the EXPRESS modeling language, numeric datatypes have a predefined and fixed width and precision (Fig. 2). ...
... Variable length data in IFC comes in various forms: (a) the majority of strings are variable length, only IFCROOT.GLOBALID has a fixed character count of 22 (b) many of the relationships have one-to-many cardinalities, for example the containment and decomposition relationships (c) geometrical types use variable length aggregates for loops and paths, but also a Cartesian point is defined as a variable length aggregate in order to re-use the same definition for 2D and 3D points [18] (d) storage for inverse attributes often results in variable length aggregates. Table 1 lists variable length (forward) attributes ordered by their prevalence in the conference center (1 g) model. ...
Article
Full-text available
The Industry Foundation Classes (IFC) are a prevalent data model in which Building Information Models can be exchanged, typically with a file-based nature. Processing the full extent of these models can be time-consuming. Considering the multi-disciplinary nature of the construction industry, stakeholders will typically only be interested in a small subset, depending on the purpose of the exchange. Therefore, the retrieval of relevant subsets, whether spatially, based on discipline, or others, is necessary to effectively consume such datasets in downstream applications. Prevalent encoding forms of IFC models are text-based and do not facilitate random-access seeking within the file and do not impose an ordering on the definition of elements within the file. Therefore, typically, the entire file needs to be read in order to find the data of interest. Furthermore, text-based data is slower to parse in comparison to binary data. This paper assesses a binary serialization format originating from the family of EXPRESS standards. It is based on an existing open, binary, hierarchical data format called HDF5 that allows random access to specific instances and therefore efficient retrieval of relevant subsets. The block-level, transparent compression yields a reduction of file sizes as compared to traditional serializations. Fully specified datatypes embedded in the exchange guarantee interoperable use. In this paper, several serialization profiles are introduced that cater to specific use cases by governing storage settings. Advanced functionality from the HDF5 library is applied to offer novel paradigms for fine-grained access rights, varying level of detail, revision management and aggregation of aspect models.
... The integration of HBIM with ontologies becomes popular to extend the capabilities of HBIM in knowledge management and conservation. Pauwels et al. [24,25] developed an automatic EXPRESS-to-OWL tool that converts the HBIM IFC model to ifcOWL ontology. Simeone, focused on the development of a semantic-enriched HBIM that integrates HBIM and a knowledge base through ontologies as a way to enhance knowledge representation and management. ...
... Ontologies play significant roles in connection with HBIM to extend the capability of HBIM in the aspect of knowledge representation and management [8,52,53]. Currently, the combination of ontology semantics and HBIM geometric elements can be conducted in different environments: (i) BIM platform (typically as Autodesk Revit) by direct BIM ad-hoc development and DB Link to connect to external database [45], (ii) ontology platform by migrating HBIM IFC files to ontology format [25], and (iii) a newly developed unified platform [27]. ...
Article
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Built heritage has been documented by reality-based modeling for geometric description and by ontology for knowledge management. The current challenge still involves the extraction of geometric primitives and the establishment of their connection to heterogeneous knowledge. As a recently developed 3D information modeling environment, building information modeling (BIM) entails both graphical and non-graphical aspects of the entire building, which has been increasingly applied to heritage documentation and generates a new issue of heritage/historic BIM (HBIM). However, HBIM needs to additionally deal with the heterogeneity of geometric shape and semantic knowledge of the heritage object. This paper developed a new mesh-to-HBIM modeling workflow and an integrated BIM management system to connect HBIM elements and historical knowledge. Using the St-Pierre-le-Jeune Church, Strasbourg, France as a case study, this project employs Autodesk Revit as a BIM environment and Dynamo, a built-in visual programming tool of Revit, to extend the new HBIM functions. The mesh-to-HBIM process segments the surface mesh, thickens the triangle mesh to 3D volume, and transfers the primitives to BIM elements. The obtained HBIM is then converted to the ontology model to enrich the heterogeneous knowledge. Finally, HBIM geometric elements and ontology semantic knowledge is joined in a unified BIM environment. By extending the capability of the BIM platform, the HBIM modeling process can be conducted in a time-saving way, and the obtained HBIM is a semantic model with object-oriented knowledge.
... By extension, parametric variables and functions on these variables may be used as part of the geometric descriptions. Parametric geometric representations have the benefit of extremely compact descriptions of geometry relative to some of the other conventions (Pauwels et al., 2017). However, these parametric descriptions are frequently the origin of geometric discrepancies between reading and writing applications, and ambiguities or errors in interpretation of the geometric recipes are applied at each end of the transmission. ...
... The resulting OWL ontology for IFC can hence be considered almost identical to the EXPRESS and XSD schemas of IFC, encoded in RDF (Open Geospatial Consortium, no date). Figure 12-5 IFC data and schema (Pauwels et al., 2017) The RDF data model inherently functions as a graph. Everything that is described with the RDF data model, follows a directed labelled graph structure. ...
... Due to the large scope of OKSTRA, only a small subset related to alignments is converted into IFC and visualised (Amann et al., 2014). Both IFC and OKSTRA have linked data specifications of the standards using the web ontology language (OWL) (Jakob Pauwels et al., 2017;Beetz and Borrmann, 2018). OIP supports writing IfcOWL for Ifc4x1 and parts of OkstraOWL in turtle and rdf format. ...
Conference Paper
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The backbone of building information modeling (BIM) processes and exchanges are digital models which contain the relevant design and production data. Thus, the quality of models being exchanged is of utmost importance to ensure transparency and avoid ambiguities. There are many BIM model viewers available on the market, being proprietary or open, free or costly. Nevertheless, the current BIM software landscape lacks open-source solutions providing user and developer friendly, versatile application programming interfaces (APIs) for management of BIM data up-to-date. TUM OpenInfraPlatform (OIP) is a open-source C++ software which provides format independent data visualisation and inspection tools. OIP supports the whole programming process-from early-binding class generation to complex computations during geometry generation, visualisation and import/export functionality for various data formats. This paper presents the architecture of the framework and more importantly the rationale behind it. It should serve as a reference to everybody interested to join the cause.
... Furthermore, Pauwels et al. optimized geometric data in ifcOWL semantic representation and proposed four alternative representations of ifcOWL geometric aspects. They also quantified the influence of these metrics on the size of ifcOWL ontology and instance models, eventually they suggested to use the well-known text (WKT) representation as an additional component for ifcOWL ontology, which greatly reduced the scale and complexity of the ifcOWL construction model [26]. ...
Article
Full-text available
The expansion of scale and the increase of complexity of construction projects puts higher requirements on the level of collaboration among different stakeholders. How to realize better information interoperability among multiple disciplines and different software platforms becomes a key problem in the collaborative process. openBIM (building information model), as a common approach of information exchange, can meet the needs of information interaction among different software well and improve the efficiency and accuracy of collaboration. To the best of our knowledge, there is currently no comprehensive survey of openBIM approach in the context of the AEC (Architecture, Engineering & Construction) industry, this paper fills the gap and presents a literature review of openBIM. In this paper, the openBIM related standards, software platforms, and tools enabling information interoperability are introduced and analyzed comprehensively based on related websites and literature. Furthermore, engineering information interoperability research supported by openBIM is analyzed from the perspectives of information representation, information query, information exchange, information extension, and information integration. Finally, research gaps and future directions are presented based on the analysis of existing research. The systematic analysis of the theory and practice of openBIM in this paper can provide support for its further research and application.
... Based on IFC, the ifcOwl ontology combines geometrical and non-geometrical aspects in one data schema. When converting an IFC building model into an ifcOwl graph, the geometry of each individual building object is defined as a large set of RDF triples (Pauwels et al., 2017b). The benchmark duplex house IFC model, for example, results in an ifcOwl RDF graph of 227 143 asserted triples, as measured by Bonduel et al. (2018a). ...
Preprint
The journal article is **reviewed and published** in the Journal of Smart Infrastructure and Construction. (Researchgate does not allow to change the "type of publication" from preprint to article). It can be accessed for free on the publisher's website: https://www.icevirtuallibrary.com/doi/10.1680/jsmic.19.00014
... In the case of smaller-size geometric objects (such as single BREP or NURBS geometries), an alternative option is to implement them as RDF-based geometry descriptions. Different implementations are discussed in [33,35,36]. Another method is to embed the content of images or geometry files of widely used geometry formats in RDF literals, e.g. using a plain string (text-based geometry) or a binary-to-text encoding such as Base64 (binary geometry). ...
Article
Building Information Modelling (BIM) has changed the way in which buildings are conceived, planned and executed. Apart from their frequent use for as-planned buildings, BIM authoring tools have now been adopted for a number of years for digitising existing buildings as well, mostly by performing a ‘scan-to-BIM’ process: the creation of a BIM model, primarily based on point clouds. However, some inherent characteristics of existing buildings are complicating such a process: uncertainties, geometric irregularities, classification of heritage building components, linking sources about the real-world asset and an interdisciplinarity that may go beyond traditional Architecture, Engineering and Construction (AEC) topics (e.g. heritage, Facility Management, sensor data and damage assessment). In this paper, a framework called ‘scan-to-graph’ (STG) is proposed to integrate the concepts of scan-to-BIM with Semantic Web technologies, as these could provide answers to the above-mentioned challenges, most notably on documentation of uncertainties, sources and modelling decisions, element classification and cross-discipline information linking. In order to test the STG concept, a use case was developed where the Audience Room of the Gravensteen castle in Ghent was reconstructed from point clouds, semantically enriched and stored as an RDF graph. The resulting graph contains multiple interlinked geometry types, metadata about the reconstruction process and the sources and allows to unambiguously refer to other contextual data on the Web.
... To fully represent and comprehend a historical/archaeological artefact, an integration with BIM and ontology can provide both object-oriented information (typically found in BIM software) and semantic information (typically found in ontological modelling systems). Currently, ontology semantics can be connected to BIM by direct ad-hoc development in BIM platform [51], migrating IFC files to RDF/OWL [132] and developing a unified platform [57]. ...
Article
Built heritage documentation involves the 3D modelling of the geometry (typically using 3D computer graphics, photogrammetry and laser scanning techniques) and information management of semantic knowledge (i.e., using Geographic Information System (GIS) and ontology tools). The recent developed Building Information Modelling (BIM) technique combines 3D modelling and information management. One of its modern application is heritage documentation and has generated a new concept of Historic/Heritage Building Information Modelling (HBIM). This paper summarises the applications of these information techniques on the built heritage documentation. We utilise Web of Science Collection to monitor the publications on built heritage documentation. We analyse the research trend in heritage modelling by comparing the attention paid by researchers before and during the 2010s. The results show that photogrammetry is always the most popular method in heritage modelling. More and more works in heritage modelling have begun to use laser scanning, computer science, GIS and especially BIM techniques. Ontologies and 3D computer graphics are traditional ways for heritage documentation. Moreover, we pay attention to the roles of BIM on heritage documentation and conduct a detailed discussion on how to extend the HBIM capabilities by integrating with other techniques. The integration provides possible enhanced functions in HBIM, including accurate parametric modelling from computer graphics, automatic semantic segmentation of 3D point cloud from reality-based modelling, spatial information management and analysis by GIS, and knowledge modelling by ontology.
... Later, a direct mapping of EXPRESS schema to OWL [4] was introduced and implemented in the current version of ifcOWL ontology. The ifcOWL is now under buildingSMART [8] International, where it eventually became a part of the ISO 16739 standard [7]. ...
Article
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Architecture, Engineering and Construction (AEC) is a fragmented industry dealing with heterogeneous data formats coming from different domains. Building Information Modelling (BIM) is one of the most important efforts to manage information collaboratively within the AEC industry. The Industry Foundation Classes (IFC) can be used as a data format to achieve data exchange between diverse software applications in a BIM process. The advantage of using Semantic Web Technologies to overcome these challenges has been recognised by the AEC community and the ifcOWL ontology, which transforms the IFC schema to a Web Ontology Language (OWL) representation, is now a de facto standard. Even though the ifcOWL ontology is very extensive, there is a lack of detailed knowledge representation in terms of process and sub-processes explaining Design for Manufacturing and Assembly (DfMA) for offsite construction, and also a lack of knowledge on how product and productivity measurement such as production costs and durations are incurred, which is essential for evaluation of alternative DfMA design options. In this article we present a new ontology named ifcOWL-DfMA as a new domain specific module for ifcOWL with the aim of representing offsite construction domain terminology and relationships in a machine-interpretable format. This ontology will play the role of a core vocabulary for the DfMA design management and can be used in many scenarios such as life cycle cost estimation. To demonstrate the usage of ifcOWL-DfMA ontol-ogy a production line of wall panels is presented. We evaluate our approach by querying the wall panel production model about information such as activity sequence , cost estimation per activity and also the direct material cost. This ultimately enable users to evaluate the overall product from the system.
... The backend of the processing web application is a Flask application [86] which uses the RDFLib library [87] to process the data modeled in RDF, and validate the constraints expressed as SHACL SPARQL functions using the pySHACL library [88]. The construction information was stored as RDF triples following OWL, RDF, ifcOWL [57,89,90], LinkOnt and SHACL ontologies. The ontology layer was handled through RDFLib, which accesses the schema definitions over the internet to determine the relationships between data. ...
Article
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In the construction sector, complex constraints are not usually modeled in conventional scheduling and 4D building information modeling software, as they are highly dynamic and span multiple domains. The lack of embedded constraint relationships in such software means that, as Automated Data Collection (ADC) technologies become used, it cannot automatically deduce the effect of deviations to schedule. This paper presents a novel method, using semantic web technologies, to model and validate complex scheduling constraints. It presents a Linked-Data based Constraint-Checking (LDCC) approach, using the Shapes Constraint Language (SHACL). A prototype web application is developed using this approach and evaluated using an OpenBIM dataset. Results demonstrate the potential of LDCC to check for constraint violation in distributed construction data. This novel method (LDCC) and its first prototype is a contribution that can be extended in future research in linked-data, BIM based rule-checking, lean construction and ADC.
... In the building data domain, some authors have dealt with this issue from solutions based on a representation of the data in RDF and OWL for different application contexts. For example, in [30] the authors analyse and propose different conversions procedures between IFC EXPRESS and OWL schemes. ...
Article
In the Architecture Engineering and Construction (AEC) industry, Building Information Model (BIM) authoring tools enable the creation of digital representations of buildings. Each tool implements its own building data model, which makes it difficult to achieve the desired interoperability when building data have to be exchanged with other software (e.g., building energy simulation tools). The representation of BIM models through open standards (e.g., IFC) and Semantic Web technologies can facilitate building data transformation in an automated and flexible way. This is achieved by taking advantage of the logical basis of the Resource Description Framework (RDF) data model and queries created in the Semantic Web query languages. The result is a pragmatic mechanism to transform the data from one data domain to another. This article analyses the potential of Semantic Web query languages to facilitate the data transformation of building data through different alternatives. The first contribution is the identification of fourteen data mapping patterns and three cases of data transformation that enable transforming one data model into another, considering the semantic and structural differences between them. The second contribution is the review and comparison of query languages to carry out the transformations through two different alternatives: using SPARQL-Generate and SPARQL Construct queries. And finally, the third contribution is the definition of a metric to assess the complexity of SPARQL queries.
... This ontology is missing many important terms, for example terms for describing a building's topology. The ifcowl ontology [135], is a semantic representation of the IFC schema (standard for representing building and construction data) [135,132] (see Section 3.2). This ontology is rich in information, it provides (directly and indirectly) all the required concepts needed to describe the building structure, its topology and the different elements contained in a space. ...
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To date, computer vision systems are limited to extract digital data of what the cameras "see". However, the meaning of what they observe could be greatly enhanced by environment and human-skills knowledge.In this work, we propose a new approach to cross-fertilize computer vision with contextual information, based on semantic modelization defined by an expert.This approach extracts the knowledge from images and uses it to perform real-time reasoning according to the contextual information, events of interest and logic rules. The reasoning with image knowledge allows to overcome some problems of computer vision such as occlusion and missed detections and to offer services such as people guidance and people counting. The proposed approach is the first step to develop an "all-seeing" smart building that can automatically react according to its evolving information, i.e., a context-aware smart building.The proposed framework, named WiseNET, is an artificial intelligence (AI) that is in charge of taking decisions in a smart building (which can be extended to a group of buildings or even a smart city). This AI enables the communication between the building itself and its users to be achieved by using a language understandable by humans.
... com/jyrkioraskari/IFCtoLBD) [23] and allows the conversion of building data into RDF graphs: so-called linked building data. Compared to previous implementations of transforming IFC-based building data into RDF graphs [25][26][27][28][29][30], data are not in one monolithic and complex graph, inherited from the equally complex and monolithic IFC standard. Instead, graphs are separated into building elements (according to BOT), products (according to PRODUCT ontology) and property set definitions (according to PROPS). ...
Article
Environmental assessment is a critical activity for ensuring buildings are performing according to specified requirements, and efficient, seamless exchange of building information is crucial for environmental assessment. Therefore, all those involved in built environment issues should be able to access and share not only building information but also data about products, especially environmental assessment results for the products used in building projects. Of the several approaches that have been proposed to achieve efficient information exchange, semantic web technologies are amongst the most promising due to their capability to share data and enhance interoperability between the most heterogeneous systems. This study proposes an approach that can be used to make environmental data available in the early phases of the building lifecycle. It relies on Semantic Web techniques, especially Linked Data principles, while building on emerging Building Information Modelling (BIM) technology to propose an approach that facilitates information exchange to enhance the sustainability assessment of buildings. The paper ends with an illustration of how lifecycle inventory databases can be integrated, linked to BIM software and used in exchanging environmental building data.
... This limits the ease and feasibility of embedding such IR checks in a wide variety of platforms. It also means that the set of specific problems of such technologies, in case of LD the inefficiencies in handling ordered lists [15], needs to be carefully considered. ...
Conference Paper
With the ever-growing digitalisation of the built environment, specifying information requirements (IR) is crucial to control the Building Information Modelling (BIM) data. However, the way of encoding these requirements is subject to a wide range of possibilities, making it difficult for the users to choose the most suitable method. The paper presents a comparative analysis of methods to define IR based on document study and expert group discussions. The study covers Data Dictionaries (ISO12006), Information Delivery Manual (IDM), IFC Property templates, Information Delivery Specification (IDS), Level of Information Need, Model View Definition (mvdXML), and Product Data Templates (PDT), as well as other, non-standardised methods such as Linked Data with SHACL. The comparison is based on criteria from the review of use-cases and covers aspects such as value constraints, properties of fields, geometry representation, metadata, expressiveness and dependency. The paper concludes that no single method covers all the discussed aspects, and selection should be made consciously based on a purpose. The results are relevant to information managers to understand the relations and differences between IR methods, suggest standardisation bodies a way forward to harmonise, integrate or differentiate the standards, and provide a framework for evaluating IR methods.
... As it is stated by W3C (The World Wide Web) Consortium: "Linked Data lies at the heart of what Semantic Web is all about: large scale integration of, and reasoning on, data on the Web." [3] Although created for the purpose of building machine-readable web of data, semantic web technologies found their way in many applications, where they have proved as invaluable for bridging the problem of heterogeneous data sources. Examples of these are linked data applications developed for GIS (Geographic Information Systems) [4] and BIM (Building Information Management) [5], but also for many other fields (medicine, agriculture, etc.). Currently the best example is the project Km4City [6], in which researchers have developed a linked data ontologies and connected applications to cover main domains within smart cities. ...
Article
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Most car manufacturers predict that in the first half of the next decade there will be fully autonomous vehicles on our roads. Such vehicles would have to communicate in order to mitigate problems caused by single-viewpoint approach. So there are a lot of researches and developments when it comes to communication layer of V2X (Vehicle-to-Everything), but there is still a lot to be done when it comes to data layer of this communication. This is why we propose using Semantic Web Technologies (SWT) to fill in gaps within data layer of V2X communication. By using SWT (Semantic Web Technologies) and Linked data, we plan to interconnect various data sources, in order to provide homogeneous way for connected autonomous vehicles (CAV) to access relevant information. Such information is currently contained in three distinctive type of sources. These are: Geo-stationary Static data sources (Maps, City models), Geostationary Dynamic data sources (IoT devices) and Non-geostationary Dynamic sources (Vehicles). Using SWT, our goal is to develop ontology(s), in such a way that in-vehicle algorithms can extract and process information about environment they are in, while taking into account available network bandwidth.
... For the purposes of the paper, we focus on the modules named IFC4 ADD1, IFC4 ADD1 extension, and factory (see Table 2). The first module is automatically generated from IFC [49], and provides a high-level characterization for classes such as product, process, and resources. The second module integrates and extends IFC4 ADD1. ...
Article
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Standards and ontologies for manufacturing understand resources differently. Because of this heterogeneity, misunderstandings arise concerning the basic features that characterize them. The purpose of the paper is to investigate how to ontologically model resources with the goal of facilitating the development of knowledge representation models for manufacturing. By reviewing the literature, we discuss and compare three approaches for the representation of resources depending on whether they are conceived in connection to either processes, plans or goals. By addressing the advantages and shortcomings of each view, we present a unifying perspective to enable the modeling of resources in an integrated manner. In this way, the intended meanings of the used notions are harmonized and, as a result, one can facilitate multiple experts to interact e.g., via data sharing and/or data integration procedures. Differently, by keeping three separated views, there is no guarantee that data coming from different parties will share common meanings even if the same terms are used. By the end of the paper, we present a case study to show the application of our approach and to compare it with an existing ontology for manufacturing.
... Structural design rule [49], ifcOWL [50,84], Semantic BIM [55], SEMERGY building model [48], Linked data ontology [42], Energy efficiency knowledge base [ A semantic model is a set of descriptions and specifications that represent information about the subjects of the problem universe, structure/hierarchy/relations of the subjects, and their properties and functions. Ontology is a schema or method to construct a semantic model by specifying how categories and concepts are defined, what properties and relations are drawn between the concepts, how data and entities substantiate the concept, and any other significance to explain the problem universe. ...
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New functions and requirements of high performance building (HPB) being added and several regulations and certification conditions being reinforced steadily make it harder for designers to decide HPB designs alone. Although many designers wish to rely on HPB consultants for advice, not all projects can afford consultants. We expect that, in the near future, computer aids such as design expert systems can help designers by providing the role of HPB consultants. The effectiveness and success or failure of the solution offered by the expert system must be affected by the quality, systemic structure, resilience, and applicability of expert knowledge. This study aims to set the problem definition and category required for existing HPB designs, and to find the knowledge acquisition and representation methods that are the most suitable to the design expert system based on the literature review. The HPB design literature from the past 10 years revealed that the greatest features of knowledge acquisition and representation are the increasing proportion of computer-based data analytics using machine learning algorithms, whereas rules, frames, and cognitive maps that are derived from heuristics are conventional representation formalisms of traditional expert systems. Moreover, data analytics are applied to not only literally raw data from observations and measurement, but also discrete processed data as the results of simulations or composite rules in order to derive latent rule, hidden pattern, and trends. Furthermore, there is a clear trend that designers prefer the method that decision support tools propose a solution directly as optimizer does. This is due to the lack of resources and time for designers to execute performance evaluation and analysis of alternatives by themselves, even if they have sufficient experience on the HPB. However, because the risk and responsibility for the final design should be taken by designers solely, they are afraid of convenient black box decision making provided by machines. If the process of using the primary knowledge in which frame to reach the solution and how the solution is derived are transparently open to the designers, the solution made by the design expert system will be able to obtain more trust from designers. This transparent decision support process would comply with the requirement specified in a recent design study that designers prefer flexible design environments that give more creative control and freedom over design options, when compared to an automated optimization approach.
... Other available ontologies can provide basic content to save a lot of work for ontology establishment. IfcOWL is one of the few ontologies in the field of building information model which is transformed from IFC (Industry Foundation Classes) and is also the only ontology recommended by BuildingSMART [14]. ifcOWL and IFC have the same limits of information representation which can represent the semantics of many concepts in the field of architecture. ...
Article
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Code compliance checking is a very important step in engineering construction, but most of code compliance checking relies on manual review at present. With the development of semantic web technology, ontology can be used to represent code information and check the code automatically. However, code ontology is established manually by researchers who have sufficient domain knowledge, in which it is easy to cause poor hierarchical structure of classes. It is also possible for code ontology not being suitable for compliance check. This paper proposes a semiautomatic construction method of railway code ontology based on ifcOWL. The railway code ontology is developed by converting ifcOWL which extends semantic information of railway code. This method can ensure the completeness of the hierarchical relationship of the classes in code ontology with good scalability, which makes use of taxonomy in ifcOWL. The establishment of ontology is divided into two processes with low coupling, namely, extension and conversion, which reduces the domain knowledge requirements of the researchers. Finally, a practical specification is selected to generate a code ontology that achieves some clauses checking.
... In the construction-related literature, these concepts are applied mainly in information extraction by BIM software (Ismail et al, 2018) (Pauwels et al, 2017) and in automated flows of data in cloud computing environment . ...
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In this paper an insight on innovative implementation strategies and operative Information and Communication Technologies (ICT) regarding Intelligent Buildings (IBs) is provided. Data-driven knowledge extraction and re-usage can be a valid source of information to study the whole building life-cycle as a process to optimize. Today, new challenges can be provided thanks to ICT and Internet of Things (IoT) paradigms that allow big data to be stored, processed and analysed. This approach is still not deeply applied in construction engineering fields. In order to analyse the related literature, first a framework to describe the IB technological environment is proposed. Second, the literature is reviewed according to this framework and focusing on ICT tools and implementation aspects for the whole building life-cycle. To the best of our knowledge, there isn't yet a survey focusing on innovative operative tools adopted in the development of the ICT technological layer of IB. The reviewed literature is discussed by identifying implemented technologies and related ICT tools and classifying applications in building life-cycle. Finally, critical aspects are singled out and opportunities for future developments in the field of IBs are outlined.
... This reference factory data model, 2 already presented in previous works [32,35], has been developed as an OWL ontology [36] since this language provides a way to generate flexible data model integrating different knowledge domains while reusing already existing technical standards (e.g. Industry Foundation Classes [37], W3C SSN/SOSA [38], UML Statechart [39]). ...
Article
Digital modelling of manufacturing systems is experiencing a fast development, but it still shows significant limitations when considering integration and interoperability of enabling technologies. Indeed, there is still a lack of reference integrated workflows to perform the wide span of tasks, ranging from layout configuration and performance evaluations to 3D representations. Commercial software tools are either too complex or expensive to be approached by non-specialists, therefore it is hard to design effective learning activities in manufacturing system engineering. This paper proposes a structured learning workflow based on an open toolkit that takes advantage of a common ontology-based data model to smoothly integrate digital tools for manufacturing system modelling, performance evaluation, and virtual reality representation. After detailing methodologies and digital tools, the proposed workflow is applied to a pilot case in higher education.
... However, the authors conclude that Semantic Web technologies could be effectively employed for defining and sharing IDM and MVD exchange requirements between stakeholders, an approach demonstrated by Lee et al. (2016). According to key authors in this field, the main barriers impeding wider utilisation of Semantic Web technologies include: the need for optimisation of data formats (given the inherent and unwieldy amounts of data involved in construction projects) as well as maintaining URI links over time (Pauwels, Krijnen, Terkaj & Beetz 2017, Pauwels, Zhang & Lee 2017, Krijnen & Beetz 2020. ...
... The transformation of the camera is described in the Viewpoint of an Issue. To express the vectors and points, bcfOWL relies on the representation in well-known-text (WKT) as proposed for the ifcOWL format in [8]. Using WKT, compatibility with GeoSPARQL [2] should be achieved, a standard of the Open Geospatial Consortium (OGC). ...
Conference Paper
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The BIM Collaboration Format (BCF) is a buildingSMART standard used to exchange issues in a digital model between heterogeneous software applications and planners. Although the BCF issues are spatially located in a model and provide links to building elements, the format is only loosely connected to the actual BIM model. While the format is well suited for its original use case, it lacks the flexibility to retrieve information from the BCF in conjunction with the BIM model. In this paper, we introduce the BIM Collaboration Format Ontology (bcfOWL), which translates the format to the Semantic Web and harnesses the expressive richness of OWL. We present the structure of the ontology and highlight the differences with existing implementations of BCF. Using example queries, we show how extended relationships between a BIM model and BCF information are enabled by bcfOWL. We show that by transferring BCF to Linked Data, the format's applicability is enhanced without losing compatibility with existing implementations and workflows. In doing so, the ontology aims to integrate into the Linked Building Data environment and facilitates access to synergies between heterogeneous building data.
... Various ontologies have been developed so far. Generic ontologies such as ifcOWL can map the established IFC data structure (Pauwels et al., 2017). Specific ontologies approach different data sets commonly used for building services engineering or cost calculations. ...
Conference Paper
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In the upcoming era of distributed technological integration known as Web3, the built environment will need to adapt. Solving the most significant social, environmental and economic challenges will likely require new approaches to data sharing and efficient data management. This will need to occur within organizations, across software tools, and between partners. However, today’s approach of data fragmentation and a scattered system of data islands prevent efficient data usage in the construction industry.The question that now arises is whether the decentralized marketplace approach has the potential to make construction data sets more uniform, efficient,and usable for all stakeholders through distributed technological integration.Therefore, this paper’s contribution isto provide a conceptual starting point and possible research stream approach towards thisquestion. Doing so by outlining current data management challenges and discussing themin comparison with already existing web3 approaches in research and industry.
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Collaboration and communication are two essential aspects of Building Information Modeling (BIM). Current practice and international standards implement BIM collaboration on the basis of domain model federation where loosely coupled models are managed as separated files and coordinated in a mostly manual fashion. The concept has severe limitations regarding concurrency and version control, as the granularity of change tracking remains on the level of complete files and does not reach individual model objects. Due to this lack of change traceability, high manual effort for the subsequent coordination across the domains is generated. These limitations can be overcome by implementing modern approaches of digital collaboration based on object-level synchronization, widely denoted as BIM level 3. This paper presents a sound methodological basis for object-based version control by (1) representing the object networks of BIM models as formal property graph structures and (2) describing changes of the model by graph transformations. Consequently, modifications can be transmitted as graph transformation rules which are subsequently integrated on the receiving side, thus achieving object-level synchronization. The paper provides the underlying theory of describing model changes by means of graph transformations and demonstrates its benefits using the example of domain models implementing the Industry Foundation Classes (IFC) as their underlying data model.
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This research proposes recommendations that could improve interoperability in the architecture, engineering, construction and operations (AECO) sector, by connecting domains, building lifecycles, and software systems with each other and the web. The objective has been to identify methods that promote evolution from file-based formats by advancing object-based data exchange solutions. The research design is a mapping of standards and systems that have affected the nature of object-based data exchanges, and which have either been proposed or implemented in AECO and the Oil & Gas sector. This is an approach which allows for the range and diversity of information to be examined. A review of the Oil & Gas sector confirms a norm where object-based, rather than file-based, transactions have shaped data exchange models, formats, use case methodologies, and collaboration mechanisms, thus contributing towards semantic connectivity across its diverse systems. Key research questions address the nature of these sectors, the promise that object-based data exchange offers, and examine recommendations that would improve standards and systems. The paper affirms that measures taken to improve interoperability in the Oil & Gas sector have relevance for the AECO sector, and that better understanding, and recognition of the structure of AECOs interoperability ecosystem is central to effecting lasting and significant change. Thus, we make recommendations that acknowledge the hybrid nature of AECO data exchanges and propose an interoperability ecosystem that connects both distributed and centralised federated models. Improved standards to define application programming interfaces (APIs) and adaptors, based on a modular approach, would be central to this proposal. We also make recommendations to improve use case definitions, and to ensure that semantic connectivity at the object level is scalable to web-based transactions. Finally, we assert that, to realise these changes, the developers and vendors of its systems should recognise and address the AECO sector’s pressing needs and concerns.
Chapter
In this chapter, we start from the typical concepts from Geographic Information System (GIS): data representation, acquisition, querying and analysis. We follow with the transition from 2 to 3D GIS and describe open standards such as CityGML and CityJSON and recent advances on 3D geospatial simulations, computing and real-time GIS and Internet of Things (IoT). Then we discuss the discrepancies in information management and modelling with respect to Building Information Modelling (BIM) and the related open standard, Industry Foundation Classes (IFC). We highlight the difference between Cartesian engineering coordinate systems and geospatial coordinate reference systems, contrast the procedural geometry definitions of IFC with the explicit geometries of GIS and look at implementation mechanisms such as boundary representations and polyhedral surface models and describe the semantic Level of Detail used in CityGML. The section that follows describes relevant processes supporting integration such as georeferencing, conversion of formats using semantic and geometric approaches and linking of heterogeneous information. We also highlight interoperability challenges that stem from consistency and validity of data, by interpreting the results of a recent benchmark on interoperability of the most common involved data formats (CityGML and IFC). We close with a conclusion and perspectives on the future with case studies on geo-enabled building permit checking and geospatial artificial intelligence and machine learning.
Chapter
In diesem Kapitel wird auf die verschiedenen Möglichkeiten zur Programmierung von BIM-Applikationen eingegangen. Ein besonderer Schwerpunkt liegt dabei auf der Verarbeitung von Daten im herstellerneutralen Austauschformat Industry Foundation Classes (IFC). In diesem Zusammenhang werden der Zugriff auf Daten im Format STEP Clear Text Encoding erläutert und dabei die Unterschiede zwischen dem Early-Binding- und dem Late-Binding-Ansatz diskutiert. Da für den Austausch von IFC-Daten das Format ifcXML eine zunehmend wichtigere Rolle einnimmt, wird auch auf den Einsatz der entsprechenden Zugriffsvarianten SAX (Simple API for XML) und DOM (Document Object Model) eingegangen. Im Anschluss wird auf verschiedene Geometrierepräsentationen der IFC und deren Interpretation Bezug genommen. Darauffolgend wird die Add-In-Entwicklung behandelt, die es erlaubt, existierende Softwareprodukte an eigene nutzungsspezifische Anforderungen anzupassen. Auch das Thema webbasierte Programmierschnittstellen (REST API) findet in diesem Kapitel Beachtung und es werden neben dem programmiertechnischen Umgang mit IFC-Daten weitere Aspekte des Datenaustauschs in Bauprojekten beleuchtet. In den letzten Abschnitten des Kapitels werden die visuelle Programmierung und die Abbildung der Industry Foundation Classes auf Semantic-Web-Technologien (RDF, SPARQL) betrachtet.
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The motivation for this work stems from an EU funded project, which focuses on leveraging digital tools for improving the renovation processes. In particular, specific tools require Linked Building Data (LBD) that need to fulfil the application-specific exchange requirements. In this research, we focus on two different use cases to investigate how to validate a Linked Building Data model. First, we study how to minimise data loss and errors when data is converted and brought into an LBD data store. The usage of unit tests to improve conversion quality is introduced. The second use case focuses on how Model View Definition (MVD) in LBD for evaluating the energy performance of the renovation designs in energy simulation can be formed. This feasibility study shows that unit test can be written the conversion. Besides validation, methods shown in the study can be used to create model views for LBD data using SHACL.
Chapter
Mit den Industry Foundation Classes (IFC) steht ein umfassendes und standardisiertes Datenformat für den herstellerneutralen Austausch von digitalen Bauwerksmodellen zur Verfügung. Es bildet damit eine wesentliche Grundlage für die Umsetzung von Big Open BIM. Das Kapitel beschreibt ausführlich den Aufbau des IFC-Datenmodells und geht im Detail auf die darin umgesetzten Ansätze zur semantischen und geometrischen Beschreibung eines Bauwerks und seiner Bauteile ein. Zudem werden die gebräuchlichsten Encodings für IFC-Instanzdaten STEP Part 21, ifcXML, RDF und IFC-JSON vorgestellt und die Möglichkeiten und Einschränkungen des IFC-Datenmodells in seiner aktuellen Form diskutiert.
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Generative computation has the potential to enhance the accuracy, effectiveness, and creativity of spatial layout in design and planning. The paper proposes a methodology to separate the knowledge about objects, spatial relationships, and constraints from the generative process. The separation between the knowledge in a domain and its possible practical uses is an important achievement of semantic technologies, because it grants access to a large body of knowledge, spanning various aspects and processes across buildings and cities, which is being codified into formal ontologies. The present study has reused existing knowledge from two established ontologies. An illustrative case-project demonstrates the suitability of the methodology for a complex layout planning problem, involving a large number of decision-makers, with multiple competing objectives and criteria. The system implements multidimensional visual interactive tools to assist designers, planners, and decision-makers in exploring the layouts and the criteria, to develop their confidence in what qualifies as a good and effective solution.
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The 28th EG-ICE International Workshop 2021 brings together international experts working at the interface between advanced computing and modern engineering challenges. Many engineering tasks require open-world resolutions to support multi-actor collaboration, coping with approximate models, providing effective engineer-computer interaction, search in multi-dimensional solution spaces, accommodating uncertainty, including specialist domain knowledge, performing sensor-data interpretation and dealing with incomplete knowledge. While results from computer science provide much initial support for resolution, adaptation is unavoidable and most importantly, feedback from addressing engineering challenges drives fundamental computer-science research. Competence and knowledge transfer goes both ways.
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Actors in the Architecture, Engineering, Construction, Owner and Operation (AECOO) industry traditionally exchange building models as files. The Building Information Modelling (BIM) methodology advocates the seamless exchange of all information between related stakeholders using digital technologies. The ultimate evolution of the methodology, BIM Maturity Level 3, envisions interoperable, distributed, web-based, interdisciplinary information exchange among stakeholders across the life-cycle of buildings. The World Wide Web Consortium Linked Building Data Community Group (W3C LBD-CG) hypothesises that the Linked Data models and best practices can be leveraged to achieve this vision in modern web-based applications. In this paper, we introduce the Building Topology Ontology (BOT) as a core vocabulary to this approach. It provides a high-level description of the topology of buildings including storeys and spaces, the building elements they contain, and their web-friendly 3D models. We describe how existing applications produce and consume datasets combining BOT with other ontologies that describe product catalogues, sensor observations, or Internet of Things (IoT) devices effectively implementing BIM Maturity Level 3. We evaluate our approach by exporting and querying three real-life large building models. Free download: http://www.semantic-web-journal.net/system/files/swj2279.pdf
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Currently, designers require to use numerous incomplete data sources and make multiple assumptions to conduct an LCA. We argue that traditional methods are incapable of addressing LCA data requirements, and for such a data and meta-data intensive task, the semantic web is the only logical choice of technology. This paper presents a review of the semantic web and its applications in the construction industry, along with an overview of the current LCA tools. LCA challenges are thoroughly discussed, and a framework using the semantic web is developed to address the data management issues of BIM-LCA applications. For comparison, the implementation is also done using an LCA tool (Tally), and a method using Relational Database Management Systems (RDBMS). Results show that the proposed method is superior to RDBMS methods in terms of capturing semantics and can improve LCA tools by providing reliable data in the early design stages.
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In F. Baader, D. Calvanese, D. McGuinness, D. Nardi, and P. F. Patel-Schneider, editors.
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As the amount of Linked Open Data on the web increases, so does the amount of data with an inherent spatial context. Without spatial reasoning, however, the value of this spatial context is limited. Over the past decade there have been several vocabularies and query languages that attempt to exploit this knowledge and enable spatial reasoning. These attempts provide varying levels of support for fundamental geospatial concepts. GeoSPARQL, a forthcoming OGC standard, attempts to unify data access for the geospatial Semantic Web. As authors of the Parliament triple store and contributors to the GeoSPARQL specification, we are particularly interested in the issues of geospatial data access and indexing. In this paper, we look at the overall state of geospatial data in the Semantic Web, with a focus on GeoSPARQL. We first describe the motivation for GeoSPARQL, then the current state of the art in industry and research, followed by an example use case, and finally our implementation of GeoSPARQL in the Parliament triple store.
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The adoption of Semantic Web methods is aimed to make various contributions to the development of the 3D Internet and its applications. The Stanford 3D scanning repository, The Digital Shape Workbench (DSW), and The AIM@SHAPE model repository, allow documentation of 3D media for sharing. Studies have shown that feature recognition for freeform shapes is challenging, when the semantics underlying the features are related to an intrinsically vague context. 3D media can represent objects that belong to a category of shapes, either in broad, unrestricted domains, or narrow, specific domain. A consideration of networking mechanisms that enable access to scientific facilities and approaches to facilitate the sharing of scientific knowledge to develop a Semantic Web infrastructure is necessary to develop effective scientific support.
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In Semantic Web languages, such as RDF and OWL, a property is a binary relation: it is used to link two individuals or an individual and a value. However, in some cases, the natural and convenient way to represent certain concepts is to use relations to link an individual to more than just one individual or value. These relations are called n-ary relations. For example, we may want to represent properties of a relation, such as our certainty about it, severity or strength of a relation, relevance of a relation, and so on. Another example is representing relations among multiple individuals, such as a buyer, a seller, and an object that was bought when describing a purchase of a book. This document presents ontology patterns for representing n-ary relations in RDF and OWL and discusses what users must consider when choosing these patterns.
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