Spatial ontologies for architectural heritage

Informatics and artificial intelligence have generated new requirements for digital archiving, information, and documentation. Semantic interoperability has become fundamental for the management and sharing of information. The constraints to data interpretation enable both database interoperability, for data and schemas sharing and reuse, and information retrieval in large datasets. Another challenging issue is the exploitation of automated reasoning possibilities. The solution is the use of domain ontologies as a reference for data modelling in information systems. The architectural heritage (AH) domain is considered in this thesis. The documentation in this field, particularly complex and multifaceted, is well-known to be critical for the preservation, knowledge, and promotion of the monuments. For these reasons, digital inventories, also exploiting standards and new semantic technologies, are developed by international organisations (Getty Institute, ONU, European Union). Geometric and geographic information is essential part of a monument. It is composed by a number of aspects (spatial, topological, and mereological relations; accuracy; multi-scale representation; time; etc.). Currently, geomatics permits the obtaining of very accurate and dense 3D models (possibly enriched with textures) and derived products, in both raster and vector format. Many standards were published for the geographic field or in the cultural heritage domain. However, the first ones are limited in the foreseen representation scales (the maximum is achieved by OGC CityGML), and the semantic values do not consider the full semantic richness of AH. The second ones (especially the core ontology CIDOC – CRM, the Conceptual Reference Model of the Documentation Commettee of the International Council of Museums) were employed to document museums’ objects. Even if it was recently extended to standing buildings and a spatial extension was included, the integration of complex 3D models has not yet been achieved. In this thesis, the aspects (especially spatial issues) to consider in the documentation of monuments are analysed. In the light of them, the OGC CityGML is extended for the management of AH complexity. An approach ‘from the landscape to the detail’ is used, for considering the monument in a wider system, which is essential for analysis and reasoning about such complex objects. An implementation test is conducted on a case study, preferring open source applications

Spatial ontologies for architectural heritage

Informatics and artificial intelligence have generated new requirements for digital archiving, information, and documentation. Semantic interoperability has become fundamental for the management and sharing of information. The constraints to data interpretation enable both database interoperability, for data and schemas sharing and reuse, and information retrieval in large datasets. Another challenging issue is the exploitation of automated reasoning possibilities. The solution is the use of domain ontologies as a reference for data modelling in information systems. The architectural heritage (AH) domain is considered in this thesis. The documentation in this field, particularly complex and multifaceted, is well-known to be critical for the preservation, knowledge, and promotion of the monuments. For these reasons, digital inventories, also exploiting standards and new semantic technologies, are developed by international organisations (Getty Institute, ONU, European Union). Geometric and geographic information is essential part of a monument. It is composed by a number of aspects (spatial, topological, and mereological relations; accuracy; multi-scale representation; time; etc.). Currently, geomatics permits the obtaining of very accurate and dense 3D models (possibly enriched with textures) and derived products, in both raster and vector format. Many standards were published for the geographic field or in the cultural heritage domain. However, the first ones are limited in the foreseen representation scales (the maximum is achieved by OGC CityGML), and the semantic values do not consider the full semantic richness of AH. The second ones (especially the core ontology CIDOC – CRM, the Conceptual Reference Model of the Documentation Commettee of the International Council of Museums) were employed to document museums’ objects. Even if it was recently extended to standing buildings and a spatial extension was included, the integration of complex 3D models has not yet been achieved. In this thesis, the aspects (especially spatial issues) to consider in the documentation of monuments are analysed. In the light of them, the OGC CityGML is extended for the management of AH complexity. An approach ‘from the landscape to the detail’ is used, for considering the monument in a wider system, which is essential for analysis and reasoning about such complex objects. An implementation test is conducted on a case study, preferring open source applications

Fachlich erweiterbare 3D-Stadtmodelle – Management, Visualisierung und Interaktion

Domain-extendable semantic 3D city models are complex mappings and inventories of the urban environment which can be utilized as an integrative information backbone to facilitate a range of application fields like urban planning, environmental simulations, disaster management, and energy assessment. Today, more and more countries and cities worldwide are creating their own 3D city models based on the CityGML specification which is an international standard issued by the Open Geospatial Consortium (OGC) to provide an open data model and XML-based format for describing the relevant urban objects with regards to their 3D geometry, topology, semantics, and appearance. It especially provides a flexible and systematic extension mechanism called “Application Domain Extension (ADE)” which allows third parties to dynamically extend the existing CityGML definitions with additional information models from different application domains for representing the extended or newly introduced geographic object types within a common framework. However, due to the consequent large size and high model complexity, the practical utilization of country-wide CityGML datasets has posed a tremendous challenge regarding the setup of an extensive application system to support the efficient data storage, analysis, management, interaction, and visualization. These requirements have been partly solved by the existing free 3D geo-database solution called ‘3D City Database (3DCityDB)’ which offers a rich set of functionalities for dealing with standard CityGML data models, but lacked the support for CityGML ADEs. The key motivation of this thesis is to develop a reliable approach for extending the existing database solution to support the efficient management, visualization, and interaction of large geospatial data elements of arbitrary CityGML ADEs. Emphasis is first placed on answering the question of how to dynamically extend the relational database schema by parsing and interpreting the XML schema files of the ADE and dynamically create new database tables accordingly. Based on a comprehensive survey of the related work, a new graph-based framework has been proposed which uses typed and attributed graphs for semantically representing the object-oriented data models of CityGML ADEs and utilizes graph transformation systems to automatically generate compact table structures extending the 3DCityDB. The transformation process is performed by applying a series of fine-grained graph transformation rules which allow users to declaratively describe the complex mapping rules including the optimization concepts that are employed in the development of the 3DCityDB database schema. The second major contribution of this thesis is the development of a new multi-level system which can serve as a complete and integrative platform for facilitating the various analysis, simulation, and modification operations on the complex-structured 3D city models based on CityGML and 3DCityDB. It introduces an additional application level based on a so-called ‘app-concept’ that allows for constructing a light-weight web application to reach a good balance between the high data model complexity and the specific application requirements of the end users. Each application can be easily built on top of a developed 3D web client whose functionalities go beyond the efficient 3D geo-visualization and interactive exploration, and also allows for performing collaborative modifications and analysis of 3D city models by taking advantage of the Cloud Computing technology. This multi-level system along with the extended 3DCityDB have been successfully utilized and evaluated by many practical projects.Fachlich erweiterbare semantische 3D-Stadtmodelle sind komplexe Abbildungen und Datenbestände der städtischen Umgebung, die als ein integratives Informationsrückgrat genutzt werden können, um eine Reihe von Anwendungsfeldern wie z. B. Stadtplanung, Umweltsimulationen, Katastrophenmanagement und Energiebewertung zu ermöglichen. Heute schaffen immer mehr Länder und Städte weltweit ihre eigenen 3D-Stadtmodelle auf Basis des internationalen Standards CityGML des Open Geospatial Consortium (OGC), um ein offenes Datenmodell und ein XML-basiertes Format zur Beschreibung der relevanten Stadtobjekte in Bezug auf ihre 3D-Geometrien, Topologien, Semantik und Erscheinungen zur Verfügung zu stellen. Es bietet insbesondere einen flexiblen und systematischen Erweiterungsmechanismus namens „Application Domain Extension“ (ADE), der es Dritten ermöglicht, die bestehenden CityGML-Definitionen mit zusätzlichen Informationsmodellen aus verschiedenen Anwendungsdomänen dynamisch zu erweitern, um die erweiterten oder neu eingeführten Stadtobjekt-Typen innerhalb eines gemeinsamen Framework zu repräsentieren. Aufgrund der konsequent großen Datenmenge und hohen Modellkomplexität bei der praktischen Nutzung der landesweiten CityGML-Datensätze wurden jedoch enorme Anforderungen an den Aufbau eines umfangreichen Anwendungssystems zur Unterstützung der effizienten Speicherung, Analyse, Verwaltung, Interaktion und Visualisierung der Daten gestellt. Die bestehende kostenlose 3D-Geodatenbank-Lösung „3D City Database“ (3DCityDB) entsprach bereits teilweise diesen Anforderungen, indem sie zwar eine umfangreiche Funktionalität für den Umgang mit den Standard-CityGML-Datenmodellen, jedoch keine Unterstützung für CityGML-ADEs bietet. Die Schlüsselmotivation für diese Arbeit ist es, einen zuverlässigen Ansatz zur Erweiterung der bestehenden Datenbanklösung zu entwickeln, um das effiziente Management, die Visualisierung und Interaktion großer Datensätze beliebiger CityGML-ADEs zu unterstützen. Der Schwerpunkt liegt zunächst auf der Beantwortung der Schlüsselfrage, wie man das relationale Datenbankschema dynamisch erweitern kann, indem die XML-Schemadateien der ADE analysiert und interpretiert und anschließend dem entsprechende neue Datenbanktabellen erzeugt werden. Auf Grundlage einer umfassenden Studie verwandter Arbeiten wurde ein neues graphbasiertes Framework entwickelt, das die typisierten und attributierten Graphen zur semantischen Darstellung der objektorientierten Datenmodelle von CityGML-ADEs verwendet und anschließend Graphersetzungssysteme nutzt, um eine kompakte Tabellenstruktur zur Erweiterung der 3DCityDB zu generieren. Der Transformationsprozess wird durch die Anwendung einer Reihe feingranularer Graphersetzungsregeln durchgeführt, die es Benutzern ermöglicht, die komplexen Mapping-Regeln einschließlich der Optimierungskonzepte aus der Entwicklung des 3DCityDB-Datenbankschemas deklarativ zu formalisieren. Der zweite wesentliche Beitrag dieser Arbeit ist die Entwicklung eines neuen mehrstufigen Systemkonzepts, das auf CityGML und 3DCityDB basiert und gleichzeitig als eine komplette und integrative Plattform zur Erleichterung der Analyse, Simulationen und Modifikationen der komplex strukturierten 3D-Stadtmodelle dienen kann. Das Systemkonzept enthält eine zusätzliche Anwendungsebene, die auf einem sogenannten „App-Konzept“ basiert, das es ermöglicht, eine leichtgewichtige Applikation bereitzustellen, die eine gute Balance zwischen der hohen Modellkomplexität und den spezifischen Anwendungsanforderungen der Endbenutzer erreicht. Jede Applikation lässt sich ganz einfach mittels eines bereits entwickelten 3D-Webclients aufbauen, dessen Funktionalitäten über die effiziente 3D-Geo-Visualisierung und interaktive Exploration hinausgehen und auch die Durchführung kollaborativer Modifikationen und Analysen von 3D-Stadtmodellen mit Hilfe von der Cloud-Computing-Technologie ermöglichen. Dieses mehrstufige System zusammen mit dem erweiterten 3DCityDB wurde erfolgreich in vielen praktischen Projekten genutzt und bewertet

Fachlich erweiterbare 3D-Stadtmodelle – Management, Visualisierung und Interaktion

Domain-extendable semantic 3D city models are complex mappings and inventories of the urban environment which can be utilized as an integrative information backbone to facilitate a range of application fields like urban planning, environmental simulations, disaster management, and energy assessment. Today, more and more countries and cities worldwide are creating their own 3D city models based on the CityGML specification which is an international standard issued by the Open Geospatial Consortium (OGC) to provide an open data model and XML-based format for describing the relevant urban objects with regards to their 3D geometry, topology, semantics, and appearance. It especially provides a flexible and systematic extension mechanism called “Application Domain Extension (ADE)” which allows third parties to dynamically extend the existing CityGML definitions with additional information models from different application domains for representing the extended or newly introduced geographic object types within a common framework. However, due to the consequent large size and high model complexity, the practical utilization of country-wide CityGML datasets has posed a tremendous challenge regarding the setup of an extensive application system to support the efficient data storage, analysis, management, interaction, and visualization. These requirements have been partly solved by the existing free 3D geo-database solution called ‘3D City Database (3DCityDB)’ which offers a rich set of functionalities for dealing with standard CityGML data models, but lacked the support for CityGML ADEs. The key motivation of this thesis is to develop a reliable approach for extending the existing database solution to support the efficient management, visualization, and interaction of large geospatial data elements of arbitrary CityGML ADEs. Emphasis is first placed on answering the question of how to dynamically extend the relational database schema by parsing and interpreting the XML schema files of the ADE and dynamically create new database tables accordingly. Based on a comprehensive survey of the related work, a new graph-based framework has been proposed which uses typed and attributed graphs for semantically representing the object-oriented data models of CityGML ADEs and utilizes graph transformation systems to automatically generate compact table structures extending the 3DCityDB. The transformation process is performed by applying a series of fine-grained graph transformation rules which allow users to declaratively describe the complex mapping rules including the optimization concepts that are employed in the development of the 3DCityDB database schema. The second major contribution of this thesis is the development of a new multi-level system which can serve as a complete and integrative platform for facilitating the various analysis, simulation, and modification operations on the complex-structured 3D city models based on CityGML and 3DCityDB. It introduces an additional application level based on a so-called ‘app-concept’ that allows for constructing a light-weight web application to reach a good balance between the high data model complexity and the specific application requirements of the end users. Each application can be easily built on top of a developed 3D web client whose functionalities go beyond the efficient 3D geo-visualization and interactive exploration, and also allows for performing collaborative modifications and analysis of 3D city models by taking advantage of the Cloud Computing technology. This multi-level system along with the extended 3DCityDB have been successfully utilized and evaluated by many practical projects.Fachlich erweiterbare semantische 3D-Stadtmodelle sind komplexe Abbildungen und Datenbestände der städtischen Umgebung, die als ein integratives Informationsrückgrat genutzt werden können, um eine Reihe von Anwendungsfeldern wie z. B. Stadtplanung, Umweltsimulationen, Katastrophenmanagement und Energiebewertung zu ermöglichen. Heute schaffen immer mehr Länder und Städte weltweit ihre eigenen 3D-Stadtmodelle auf Basis des internationalen Standards CityGML des Open Geospatial Consortium (OGC), um ein offenes Datenmodell und ein XML-basiertes Format zur Beschreibung der relevanten Stadtobjekte in Bezug auf ihre 3D-Geometrien, Topologien, Semantik und Erscheinungen zur Verfügung zu stellen. Es bietet insbesondere einen flexiblen und systematischen Erweiterungsmechanismus namens „Application Domain Extension“ (ADE), der es Dritten ermöglicht, die bestehenden CityGML-Definitionen mit zusätzlichen Informationsmodellen aus verschiedenen Anwendungsdomänen dynamisch zu erweitern, um die erweiterten oder neu eingeführten Stadtobjekt-Typen innerhalb eines gemeinsamen Framework zu repräsentieren. Aufgrund der konsequent großen Datenmenge und hohen Modellkomplexität bei der praktischen Nutzung der landesweiten CityGML-Datensätze wurden jedoch enorme Anforderungen an den Aufbau eines umfangreichen Anwendungssystems zur Unterstützung der effizienten Speicherung, Analyse, Verwaltung, Interaktion und Visualisierung der Daten gestellt. Die bestehende kostenlose 3D-Geodatenbank-Lösung „3D City Database“ (3DCityDB) entsprach bereits teilweise diesen Anforderungen, indem sie zwar eine umfangreiche Funktionalität für den Umgang mit den Standard-CityGML-Datenmodellen, jedoch keine Unterstützung für CityGML-ADEs bietet. Die Schlüsselmotivation für diese Arbeit ist es, einen zuverlässigen Ansatz zur Erweiterung der bestehenden Datenbanklösung zu entwickeln, um das effiziente Management, die Visualisierung und Interaktion großer Datensätze beliebiger CityGML-ADEs zu unterstützen. Der Schwerpunkt liegt zunächst auf der Beantwortung der Schlüsselfrage, wie man das relationale Datenbankschema dynamisch erweitern kann, indem die XML-Schemadateien der ADE analysiert und interpretiert und anschließend dem entsprechende neue Datenbanktabellen erzeugt werden. Auf Grundlage einer umfassenden Studie verwandter Arbeiten wurde ein neues graphbasiertes Framework entwickelt, das die typisierten und attributierten Graphen zur semantischen Darstellung der objektorientierten Datenmodelle von CityGML-ADEs verwendet und anschließend Graphersetzungssysteme nutzt, um eine kompakte Tabellenstruktur zur Erweiterung der 3DCityDB zu generieren. Der Transformationsprozess wird durch die Anwendung einer Reihe feingranularer Graphersetzungsregeln durchgeführt, die es Benutzern ermöglicht, die komplexen Mapping-Regeln einschließlich der Optimierungskonzepte aus der Entwicklung des 3DCityDB-Datenbankschemas deklarativ zu formalisieren. Der zweite wesentliche Beitrag dieser Arbeit ist die Entwicklung eines neuen mehrstufigen Systemkonzepts, das auf CityGML und 3DCityDB basiert und gleichzeitig als eine komplette und integrative Plattform zur Erleichterung der Analyse, Simulationen und Modifikationen der komplex strukturierten 3D-Stadtmodelle dienen kann. Das Systemkonzept enthält eine zusätzliche Anwendungsebene, die auf einem sogenannten „App-Konzept“ basiert, das es ermöglicht, eine leichtgewichtige Applikation bereitzustellen, die eine gute Balance zwischen der hohen Modellkomplexität und den spezifischen Anwendungsanforderungen der Endbenutzer erreicht. Jede Applikation lässt sich ganz einfach mittels eines bereits entwickelten 3D-Webclients aufbauen, dessen Funktionalitäten über die effiziente 3D-Geo-Visualisierung und interaktive Exploration hinausgehen und auch die Durchführung kollaborativer Modifikationen und Analysen von 3D-Stadtmodellen mit Hilfe von der Cloud-Computing-Technologie ermöglichen. Dieses mehrstufige System zusammen mit dem erweiterten 3DCityDB wurde erfolgreich in vielen praktischen Projekten genutzt und bewertet

Semantic Integration in MADS Conceptual Model

Our vision of a viable way for transparent and meaningful processing of heterogeneous spatio-temporal data is to put data semantics in the foundation of an integration process. We present and correlate means of integration as components of the mediation level of an interoperable system. For our domain of interest we present MADS domain ontologies and MADS conceptual data model dedicated to modeling of spatio-temporal data. Using as example two MADSschemas we outline an integration methodology based on semantic interschema correspondence assertions and integration goals

ARIADNE: A Research Infrastructure for Archaeology

Research e-infrastructures, digital archives, and data services have become important pillars of scientific enterprise that in recent decades have become ever more collaborative, distributed, and data intensive. The archaeological research community has been an early adopter of digital tools for data acquisition, organization, analysis, and presentation of research results of individual projects. However, the provision of e-infrastructure and services for data sharing, discovery, access, and (re)use have lagged behind. This situation is being addressed by ARIADNE, the Advanced Research Infrastructure for Archaeological Dataset Networking in Europe. This EU-funded network has developed an e-infrastructure that enables data providers to register and provide access to their resources (datasets, collections) through the ARIADNE data portal, facilitating discovery, access, and other services across the integrated resources. This article describes the current landscape of data repositories and services for archaeologists in Europe, and the issues that make interoperability between them difficult to realize. The results of the ARIADNE surveys on users’ expectations and requirements are also presented. The main section of the article describes the architecture of the e-infrastructure, core services (data registration, discovery, and access), and various other extant or experimental services. The ongoing evaluation of the data integration and services is also discussed. Finally, the article summarizes lessons learned and outlines the prospects for the wider engagement of the archaeological research community in the sharing of data through ARIADNE

Query processing of geometric objects with free form boundarie sin spatial databases

The increasing demand for the use of database systems as an integrating factor in CAD/CAM applications has necessitated the development of database systems with appropriate modelling and retrieval capabilities. One essential problem is the treatment of geometric data which has led to the development of spatial databases. Unfortunately, most proposals only deal with simple geometric objects like multidimensional points and rectangles. On the other hand, there has been a rapid development in the field of representing geometric objects with free form curves or surfaces, initiated by engineering applications such as mechanical engineering, aviation or astronautics. Therefore, we propose a concept for the realization of spatial retrieval operations on geometric objects with free form boundaries, such as B-spline or Bezier curves, which can easily be integrated in a database management system. The key concept is the encapsulation of geometric operations in a so-called query processor. First, this enables the definition of an interface allowing the integration into the data model and the definition of the query language of a database system for complex objects. Second, the approach allows the use of an arbitrary representation of the geometric objects. After a short description of the query processor, we propose some representations for free form objects determined by B-spline or Bezier curves. The goal of efficient query processing in a database environment is achieved using a combination of decomposition techniques and spatial access methods. Finally, we present some experimental results indicating that the performance of decomposition techniques is clearly superior to traditional query processing strategies for geometric objects with free form boundaries

Enabling European archaeological research: The ARIADNE E-infrastructure

Research e-infrastructures, digital archives and data services have become important pillars of scientific enterprise that in recent decades has become ever more collaborative, distributed and data-intensive. The archaeological research community has been an early adopter of digital tools for data acquisition, organisation, analysis and presentation of research results of individual projects. However, the provision of einfrastructure and services for data sharing, discovery, access and re-use has lagged behind. This situation is being addressed by ARIADNE: the Advanced Research Infrastructure for Archaeological Dataset Networking in Europe. This EUfunded network has developed an einfrastructure that enables data providers to register and provide access to their resources (datasets, collections) through the ARIADNE data portal, facilitating discovery, access and other services across the integrated resources. This article describes the current landscape of data repositories and services for archaeologists in Europe, and the issues that make interoperability between them difficult to realise. The results of the ARIADNE surveys on users' expectations and requirements are also presented. The main section of the article describes the architecture of the einfrastructure, core services (data registration, discovery and access) and various other extant or experimental services. The ongoing evaluation of the data integration and services is also discussed. Finally, the article summarises lessons learned, and outlines the prospects for the wider engagement of the archaeological research community in sharing data through ARIADNE

Ontology based data warehousing for mining of heterogeneous and multidimensional data sources

Heterogeneous and multidimensional big-data sources are virtually prevalent in all business environments. System and data analysts are unable to fast-track and access big-data sources. A robust and versatile data warehousing system is developed, integrating domain ontologies from multidimensional data sources. For example, petroleum digital ecosystems and digital oil field solutions, derived from big-data petroleum (information) systems, are in increasing demand in multibillion dollar resource businesses worldwide. This work is recognized by Industrial Electronic Society of IEEE and appeared in more than 50 international conference proceedings and journals