LDAC2020 - 8th Linked Data in Architecture and Construction Workshop (17-19 June 2020)

The LDAC workshop series provides a focused overview on technical and applied research on the usage of semantic web, linked data and web of data technologies for architecture and construction (design, engineering, construction, operation, etc.). The workshop aims at gathering researchers, industry stakeholders, and standardization bodies of the broader Linked Building Data (LBD) community. The aim of the workshop is to present current developments, coordinate efforts, gather stakeholders, and elaborate use cases.


These sessions, which take place after the introduction in the morning of the 17th and keynote on the 18th of June (wednesday and thursday), focus on current research and developments on linked building data, with the following presentations:

Wednesday 17 June (10:00 - 12:00)

  • From obXML to the OP Ontology: Developing a Semantic Model for Occupancy Profile
  • Serge Chavez-Feria, Giorgos Giannakis, Raul García-Castro, and María Poveda-Villalón
  • Abstract: Building energy performance simulation is vital for predicting energy performance under specific conditions. Even though there exist several calculation methodologies that can provide precise simulation approximations, the accuracy of these tools is affected by the level of detail of its input data, being occupant behavior the main source of uncertainty in building energy performance results. Hence, initiatives such as the obXML schema have been developed recently to get a deeper understanding and to generate a more elaborated description of these data. Besides, the use of semantic web technologies can open opportunities to link behavioral patterns with other building information and related domains allowing interoperability and heterogeneous data integration. This paper presents the Occupancy Profile ontology, a semantic model based on obXML that allows the representation of occupant behaviors and actions inside building spaces. This paper also provides a catalogue of modelling decisions taken during the development and an example.
  • Linked Data for Smart Homes: Comparing RDF and Labeled Property Graphs
  • Alex J. A. Donkers, Dujuan Yang, and Nico Baken
  • Abstract: The need to integrate siloed data in the built environment led to a gaining interest in semantic web technologies in the Architecture, Engineering and Construction (AEC) sector. Especially for smart home developments, the integration of information about the building, users and (IoT) devices could be valuable. RDF is the standard model for the semantic web, however, labeled property graphs also proved to be effective in linking data. This research used two case study datasets to compare the two graph models both qualitatively and quantitatively. First, the state-of-the-art of semantic web technology for smart homes is elaborated upon, after which the two graph models are described. The comparison shows that native labeled property graphs are less complex and outmatch the atomic RDF in complex graph traversals. However, RDF shows qualitative advantages for multi-domain and multi-stakeholder environments, such as the use of ontologies and HTTP URIs, making it a more stable interoperability format.
  • Towards defining Data Usage Restrictions in the Built Environment
  • Gonzalo Gil and Iker Esnaola-Gonzalez
  • Abstract: The building sector consumes about 40% of global energy, which is largely caused by buildings’ operations. Research showed that providing users with detailed consumption and appliance-usage data may engage them in energy efficiency activities. To do so, data analytics services must be deployed by third parties. This services require huge amount of data from the users in order to offer high quality services. Nevertheless, users are reluctant to share their data especially if its private. This is the case of those measurements performed inside the buildings that describes users behaviour. In these scenarios, data sovereignty plays a key role as it provides a solution to guarantee data owners that their data is being used as they defined initially in textual contracts. In this way, the owners predisposition to exchange their data is expected to increase. In this article, focus is placed in the specification of machine-interpretable policies for built environments based on data owners’ defined textual contracts. For that, domain-agnostic usage control specification IDSA approach is combined with built environment ontologies which define the resources to which usage restrictions apply. Furthermore, this approach has been implemented in a real-world home use case.
  • Design and integration of the project-specific ontology for data analytics support
  • Miloš Šipetić, Reinhard Jentsch, Judit Aizpuru, and Jan Kurzidim
  • Abstract: Data analytics projects often have access to little or no metadata associated with data collected and intended for processing, data analysis or machine learning. Even when metadata is available, it is usually poorly described, structured and linked to the corresponding data. In H2020 project Inbetween, metadata description problem is approached by designing the project ontology on top of established ontologies such as BOT, SAREF and SAREF4BLDG. An approach for structuring and integrating all the collected data about occupants, their dwellings, appliances, sensors and locations into the project knowledge base is described. Building monitoring data, weather observation and forecast streams stored in SQL-based and time-series databases are semantically linked to the corresponding sensor information. Two data analysis use cases are discussed, along with improvements and benefits enabled by using the linked data approach. Discussed use cases are virtual occupancy sensor and electricity load profiling service. Linked data approach, and use of common and standardized dictionaries help designing data analysis workflows that are easier to test, reuse, reason about.
  • Wednesday 17 June (14:00 - 16:00)

  • A GIS-based Ontology for Representing the Surrounding Environment of Buildings to Support Building Renovation
  • Maryam Daneshfar, Timo Hartmann, and Jochen Rabe
  • Abstract: This research focuses on developing an ontology for representing knowledge about the surrounding environment of a building. The ontology can be useful to create a knowledge management system for different experts in the process of the building renovation, to extend the information and stretch the domain from the individual building to the environment. Knowledge about what entities and attributes to select is captured based on literature and investigating the pilot demonstration sites. Such an ontology can help to structure the surrounding data to support processes in different stages of the renovation. Moreover, it can be valuable in further studies of integrating data of various sources for construction purposes.
  • Integration of BIM-related bridge information in an ontological knowledgebase
  • Al-Hakam Hamdan and Raimar J. Scherer
  • Abstract: Currently, utilizing digital representations of bridge constructions is still limited to geometry-based models with none or only little semantic data. Consequently, assessing these models require the interpretation of external sources, e.g. relational databases or reports. Despite new approaches in the Building Information Modeling (BIM) domain such as the IFC-Bridge extension for the Industry Foundation Classes (IFC), try to provide models where geometric and semantic data are combined, a great proportion of information from current and future domains that are relevant for the bridge industry are not covered. For this reason, an extensible web ontology inspired from the Building Topology Ontology (BOT) for buildings, has been developed, which functions as a core ontology for bridge representations and therefore covers all necessary general information used in this domain. In this regard, the developed core ontology is interlinked with multiple domain specific bridge extensions in a bridge ontology framework that is applied on a test scenario. In this paper, the components of the bridge ontology framework are explained as well as the application on the test case. In addition, ontology alignments for BOT and ifcOWL are proposed as well as shapes for ontology validation. Furthermore, the functionality of a developed software prototype is described that generates the bridge ontology from a given IFC model.
  • Validation of IfcOWL datasets using SHACL
  • Sander Stolk and Kris McGlinn
  • Abstract: Standardisation is an important part of ensuring data interoperability. Industry Foundation Classes (IFC) is the current leading standard for BIM in the Architecture Engineering and Construction (AEC) industry and ifcOWL is a Resource Description Framework (RDF) representation of IFC, which enables the interlinking of IFC models with other building and building related data represented also using RDF, such as device, sensor, geolocation, etc. IFC has a complex schema, designed to support parametric modelling in AEC and adherence to this schema is required to support import of IFC models into popular CAD tools such as Autodesk and ArchiCAD. Therefore for those wishing to create ifcOWL models which can then be imported into these tools, a process of validation of the output must be done. In this paper we present a method for validating ifcOWL models using SHACL which can be reused by anyone generating ifcOWL models and which returns a report highlighting any issues identified. The method is tested to validate the outputs of a conversion of geospatial data into IFC using a declarative mapping approach, called R2RML.

Thursday 18 June (11:00 - 12:30)

  • Pattern-based access control in a decentralised collaboration environment
  • Jeroen Werbrouck, Ruben Taelman, Ruben Verborgh, Pieter Pauwels, Jakob Beetz, and Erik Mannens
  • Abstract: As the building industry is rapidly catching up with digital advancements, and Web technologies grow in both maturity and security, a data- and Web-based construction practice comes within reach. In such an environment, private project information and open online data can be combined to allow cross-domain interoperability at data level, using Semantic Web technologies. As construction projects often feature complex and temporary networks of stakeholder firms and their employees, a property-based access control mechanism is necessary to enable a flexible and automated management of distributed building projects. In this article, we propose a method to facilitate such mechanism using existing Web technologies: RDF, SHACL, WebIDs, nanopublications and the Linked Data Platform. The proposed method will be illustrated with an extension of a custom nodeJS Solid server. The potential of the Solid ecosystem has been put forward earlier as a basis for a Linked Data-based Common Data Environment: its decentralised setup, connection of both RDF and non-RDF resources and fine-grained access control mechanisms are considered an apt foundation to manage distributed digital twins.
  • Common Data Environments for the Information Container for Document Delivery
  • Madhumitha Senthilvel, Jyrki Oraskari, and Jakob Beetz
  • Abstract: Unstructured and poorly managed information is a major cause of time delays in construction projects. Availability of relevant information at the required time has a considerable impact on decision making in the course of the project. Multi-models containers, and a more recent approach, Information Container for Linked Document Delivery (ICDD), aim to facilitate construction data management and sharing information. Containers help in structuring and linking of heterogenous data. Such container models are relevant in and align with Common Data Environments (CDE) which facilitate a centralized environment for managing both information and services. Presently, there are two approaches fit in the vision of CDE: the DIN SPEC 91391-2 on which the OpenCDE-API is loosely based on, and the W3C Linked Data Platform (LDP),a generic data container-based approach to managing linked data graphs online. In this paper, we investigate how ICDD, an approach to link information, can be represented using the above two frameworks. A comparison is developed between the two approaches based on a sample use-case. The required conversion steps are analysed, and the limitations of the mapping are evaluated.The sample use-case is used to assess them.
  • Mapping IFC and GIS conceptual schemas via Ontologies
  • Elio Hbeich and Ana Roxin
  • Abstract: Data interpretation refers to the execution of processes through which data is reviewed to achieve an informed conclusion. As result, the data interpretation assigns a meaning to the information analyzed and determines its signification and implications. Based on BIM and GIS standards, formats, etc. we have noticed that each domain interpreted data in different contexts, objectives and purposes. Where on one hand, BIM represents a 3D modelbased process that gives architecture, engineering, and construction professionals the insight and tools to more efficiently plan, design, construct, and manage buildings and infrastructure and on the other hand, GIS allows capturing, storing, handling and analyzing geographical data (Sahoo, 2017). While previous work focuses on integrating or unifying IFC with GIS application (e.g. CityGML, etc.) to treat specific use cases. In this article, we are focusing on giving a list of semantic links (mapping) between GIS (represented by different ISO 19XXX standard) and BIM (embodied by IFC model) concepts and properties to ensure interpretation continuity between both domains that enable us to place building context characteristic and impact in urban environment.


On the afternoon of June 20 (thursday) we will focus on recent developments and proposals from the industry, with the following presentations:

Session 1 (14:00 - 17:30)

  • General, using linked data solutions to integrate the construction industry
  • John Egan
  • Abstract: An independent report suggests Cost of double data entry incurs 73% productivity loss, 70% slowed info workflows, 62% frequency of data entry errors (Source: connectedaec.com) when exchanging information between common data environments. Shaped by requirements set out in international information management standards, CDEs are faced with both technical and governance based challenges to connect data sources. Linked data can be a means to create an environment for multiple project management systems to lift the barriers and allow seamless flow of information that can fundamentally change the way we work together on projects as an industry. With the growth and continuous disintegration of platforms and Applications I will discuss what it will take for linked data solutions to “integrate” with the construction industry.
  • General, data communication between disparate design applications using Neo4J and GraphQL
  • Will Reynolds
  • Abstract: A big inefficiency in building design lies in communicating data between disparate design applications. This talk will explore how a graph database (specifically Neo4j), and a query language (GraphQL), can provide a common source of truth from which these applications can easily push and pull the data they need. To further present the viability of the concept we’ll consider how a cloud hosted API server (GRANDstack) can provide a single, scalable, endpoint for building data throughout its lifecycle. We’ll explore how graph data adds huge value by capturing important relationships between these components which are a key step towards achieving building data utopia.
  • Norms/standards, BIM standards ISO 23386 and ISO 23387
  • Lars Christian Fredenlund
  • Abstract: Presentation of the two BIM standards EN ISO 23386 Development of properties using interconnect dictionaries and EN ISO 23387 Data Templates for construction objects. These standards are needed for construction platforms, software to connect towards Manufacturers and to take a step towards Circular Economy, Green deal whilst ensuring implementation of Construction Products Regulation, Low volt directive. This will provide the golden tread that Linjed data can use to provide an eruption of our industry.
  • On integration between manufacturer data and building models using linked data in compliance with ISO 23386
  • Nicolas Bus
  • Abstract: Manufacturers usually produce data on products using corporates data structures and vocabularies. How have them sharing a common frame to help customer comparing products ? how to integrate manufacturer data with building models ? The ISO 23386 standard defines common process and meta-data to implement and manage a properties thesaurus called data dictionary. In this presentation we describe an approach to implement ISO 23386 with benefits from Linked Data. Do you we need new vocabularies ? or can we just align ISO 23386 ontology on existing Link Data vocabularies ? In first application we show how building experts can use a Linked Data oriented Data Dictionnaries compliant with ISO23386 at design stage. How can they deal with the various international classifications ? We show this application through the business case of a French company delivering certificates on building. The second application concern building owners using products databases for retrofitting. How to link products with properties thesaurus? How to integrates data from Building elements and manufacturer products ? This use case came from the BIM4REN European project.
  • On the FireGraph knowledge graph that utilizes LBD ontologies
  • Bart van Leeuwen
  • Abstract: Netage B.V. has created FireGraph a knowledge graph for the fire service where we have used the current version of BOT to link into building information from various sources to improve the information position of fire services. Based on open standards FireGraph provides fire services with a information architecture on top of which they can build their information products either for operations or for preparation. Due to the scattered nature of data available to the fire service integrating these sources is in general cumbersome, with the knowledge graph approach we have enabled fire services to get a complete overview of the available information regardless of what the datasource is. To integrate the various sources of building information we have utilized the Ontologies which are under construction in the Linked Building Data working group.
  • On the need for "more lenses to view the same data", connecting structured and unstructured data and making it available using structures defined in ISO 81346
  • Philipp Dohmen
  • Abstract: Data-driven analytics is at the core of global businesses today and the construction industry of tomorrow. But any good data analytics strategy requires a capacity to quickly obtain valuable insights from large amounts of data coming from diverse data sources. For real benefits it is necessary to connect structured and unstructured Data to gain better insights for planning, construction and operations. Todays problem is the essential need of complete different data structures per stage. The datastructure designed in ifc is for planning but doesn’t solve the needs of a construction site or operations.

Session 2 (15:45 - 17:00)

  • Data integration, FM, practical use case from schiphol airport, asset data management
  • Jan Voskuil
  • Abstract: Schiphol (the international airport) has outsourced to 6 Main Contractors (MCs) the management of its 70,000 assets, ranging from doors and elevators to landing guidance systems and Airplane Docking Stations. Each MC is the single source of truth regarding asset information. With each update, the MC sends a message containing the full description of the pertinent asset to SNBV’s CDV, the “central data hub”, a high-performance native RDF graph database with application layer. The data are published in near-real time to the Asset Viewer. Data stewards use the CDV for data governance and quality monitoring, based on business and validation rules in SHACL. In the future, apps will be created that use the auto-generated GraphQL API. We at Taxonic are now in the process of productizing the solution. We have partnered up with Macomi, specialized in state-of-the-art asset analytics, for predictive maintenance, line-of-sight monitoring, long-term scenario evaluation and the like. Our vision is that asset data must be FAIR. In this talk, I will talk about this vision, on how our first implementation at Schiphol worked out, and on what we learned from it. And what we are planning. With an eye on challenges related to OTLs and ontologies.
  • Infrastructure, roads, Bjørnafjorden Open Live Centre (BOLC) and the V440 ontology
  • Lars Wikström
  • Abstract: The presentation will give an overview of the state in a large infrastructure project in Norway, E39 Coastal Highway, where a concept called Bjørnafjorden Open Live Centre (BOLC), an interactive web-portal for live project information, is introduced. This portal shall manage data from many different sources and data formats. To manage all these data types in a structured way, a well-suited classification system is key. The Norwegian Road Authority has a classification system defined in their handbook for bridge registration; V440, used for planning, design, construction, maintenance and operations. The project develops an ontology representing V440 based on LD/SW-technologies. The development is led by the Technical Room of BuildingSMART Norway. The resulting ontology, including support for linking to other relevant ontologies, will be available for all stakeholders. Currently, the project is in a phase where PoC:s (Proof-of-concept) are being developed together with software companies. When the BOLC web-portal is realized, then this will be a full scaled pilot project for how to apply the LD/SW techniques for classification of data from a variety of domains, sources and formats. This will be something new and unique in this scale and really show how open standards can support advanced open BIM projects.
  • Smart buildings, integration between a maintenance management system and a SCADA
  • Eduardo Gilabert
  • Abstract: BIM (Building Information Modelling) is a collaborative working methodology for the creation and management of constructive projects. Its objective is the centralization of all the project information, generated by all the agents, into a digital representation model. However, as it happens more often than not, the overuse of buzzwords or trendy terms diffuse true sense and BIM is no exception. The BIM shouldn’t be confused with IFC files, which are mainly restricted to exchange geometrical building data. Instead, a BIM must be understood as a central model which includes, links and integrates information that covers the whole building life cycle. Certainly, the Semantic Technologies can contribute to the integration of these heterogeneous data sources, and allow easy and intuitive ways to rapidly browse, query and use this information. In the context of the NIERBIMO project, the integration between a CMMS (Computerized Maintenance Management System) and a SCADA containing building data is aimed via the use of BIM, with the main target of making a more efficient and sustainable use of energy, operation and maintenance in buildings starting from the planning phase.
  • Smart buildings, Google's own real estate, brick, haystack
  • Charbel Kaed
  • Abstract: Google manages its own real estate by collecting data from different buildings to better manage them and optimize their operations. In this work, we present our internal platform which collects data from BMS systems and our Digital Buildings ontology, based on HayStack and Brick in order to semantically represent 130 buildings from Google’s buildings in the California Bay Area region. The ontology proposed in this work is designed with our subject matter expert in HVAC mechanical systems.