Armin Haller

• PhD
• Professor (Associate) at Australian National University

Empirical study designs in HCI evolve in response to temporal realities and technological advancements. In this context, virtual reality (VR) shows potential for new empirical research designs, going beyond the (still) quite dominantly lab-based research roots in HCI. Previous work has been conducted to identify the use of VR for gathering non-homo...

The real-time evaluation of content quality on knowledge-sharing platforms is a critical area of research with significant implications for both academia and industry. Timely feedback mechanisms are essential for enhancing user satisfaction and motivating contributors, particularly new users, by influencing their behaviors toward higher-quality con...

In the context of Natural Language Processing (NLP) and Semantic Web applications, constructing Knowledge Graphs (KGs) from unstructured text plays a vital role. Several techniques have been developed for KG construction from text, but the lack of standardized datasets hinders the evaluation of triple extraction methods. The evaluation of existing...

The exponential growth of textual data in the digital era underlines the pivotal role of Knowledge Graphs (KGs) in effectively storing, managing, and utilizing this vast reservoir of information. Despite the copious amounts of text available on the web, a significant portion remains unstructured, presenting a substantial barrier to the automatic co...

As online education gains popularity during the Pandemic, Massive Open Online Courses (MOOCs) re-emerged as an essential mode of learning. A MOOC can be treated as a knowledge product and, MOOC platforms, therefore, become marketplaces for participants to trade these products. Price, as a critical market factor, performs a role in determining consu...

Knowledge-sharing in forums is an integral part of many MOOCs (Massive Open Online Courses). However, forum usage for knowledge-sharing in MOOCs is often inadequate. This study adopts a mixed-methods approach to investigate problems behind MOOC learners’ problematic forum participation and propose real-time sharing-quality-monitoring mechanisms to...

End-user Gesture Elicitation Studies (GESs) are the cornerstone of gesture design research and are used extensively when designing gesture-controlled interfaces. With the increasing accessibility of consumer-grade immersive devices, GESs are reshaping towards encapsulated studies using VR as a medium. These VR GESs appear to be effective in address...

Open science knowledge has significant value, yet this value can only be realised if the knowledge is accessible, findable and retrievable. Although it is well-documented that detailed metadata are important, the more critical point is what factors are more important and worth of more investments and managerial efforts. We collect data from a major...

Community question answering (CQA) sites have developed into vast collections of valuable knowledge. Questions, as CQA's central component, go through several phases after they are posted, which are often referred to as the questions' lifecycle or questions' lifespan. Different questions have different lifecycles, which are closely linked to the to...

Online Question and Answering services (Q&As) are becoming increasingly popular among information seekers. Users on these platforms identify their information needs by asking questions and interacting with others. Frequent user activities have led to a significant increase in traffic on Q&As, which motivates researchers to study the driving factors...

Wikidata has become one of the most prominent open knowledge graphs (KGs) on the Web. Relying on a community of users with different expertise , this cross-domain KG is directly related to other data sources. This paper investigates how Wikidata is linked to other data sources in the Linked Data ecosystem. To this end, we adapt previous definitions...

Enterprise and public Knowledge Graphs (KGs) are known to be incomplete. Methods for automatic completion, sometimes by rule learning, scale well. While previous rule-based methods learn closed (non-existential) rules, we introduce Open Path (OP) rules that are constrained existential rules. We present a novel algorithm, OPRL, for learning OP rules...

Wikidata has become one of the most prominent open knowledge graphs (KGs) on the Web. Relying on a community of users with different expertise, this cross-domain KG is directly related to other data sources. This paper investigates how Wikidata is linked to other data sources in the Linked Data ecosystem. To this end, we adapt previous definitions...

Gesture Elicitation Studies (GES) are a widely used empirical method to develop gesture vocabularies, interaction models and methods for gesture-based systems in different contexts. While GES show great promise to identify user-defined gestures, there are inherent problems with current methods used for GES. Especially during the ongoing pandemic, i...

Extraction of categorised named entities from text is a complex task given the availability of a variety of Named Entity Recognition (NER) models and the unstructured information encoded in different source document formats. Processing the documents to extract text, identifying suitable NER models for a task, and obtaining statistical information i...

This book constitutes the proceedings of the 20th International Semantic Web Conference, ISWC 2021, which took place in October 2021. Due to COVID-19 pandemic the conference was held virtually. The papers included in this volume deal with the latest advances in fundamental research, innovative technology, and applications of the Semantic Web, linke...

Users are posting millions of questions on Community question answering sites each day. The quality of those questions significantly affects the satisfactions of the sites' users and, therefore, sites' traffic. We gathered 15 question-quality related features from one of the largest CQA sites and the site's pageview data to estimate the scale of th...

Users are posting millions of questions on Community question answering (CQA) sites each day. The quality of those questions significantly affects the satisfactions of the sites' users and, therefore, sites' traffic. We gathered 15 question-quality related features from one of the largest CQA sites and the site's page view data to estimate the scal...

Knowledge graph creation and maintenance is difficult for naïve users. One barrier is the paucity of user friendly publishing tools that separate schema modeling from instance data creation. The Shapes Constraint Language (SHACL), a W3C standard for validating RDF based knowledge graphs, can help. SHACL enables domain relevant structure , expressed...

Gesture-controlled interfaces are becoming increasingly popular with the growing use of Internet of Things (IoT) systems. In particular , in automobiles, smart homes, computer games and Augmented Reality (AR) / Virtual Reality (VR) applications, gestures have become prevalent due to their accessibility to everyone. Designers, producers, and vendors...

Ontologies expressed in OWL and their associated SHACL [4] constraints contain detailed metadata and assumptions on Knowledge Graphs (KGs). With this information comes the possibility of developing front-end applications that interact with these KGs. These opportunities are often unrealised as Web developers are required to interpret OWL and SHACL...

This manuscript introduces J2RM: a tool to process mappings from JSON data to RDF triples guided by an OWL2 ontology structure. The mappings are defined as annotation properties associated with each ontology entity of interest. They are embedded in an ontology file so that they can be readily deployed and shared to automate RDF-graph creation. In t...

Knowledge Graphs (KGs) proliferating on the Web are well known to be incomplete. Much research has been proposed for automatic completion, sometimes by rule learning, that is known to scale well. All existing methods learn closed rules. In this paper, we introduce open path (OP) rules and present a novel algorithm, oprl, for learning OP rules. Whil...

Knowledge graph creation and maintenance is difficult for naïve users. One barrier is the paucity of user friendly publishing tools that separate schema modeling from instance data creation. The Shapes Constraint Language (SHACL) [12], a W3C standard for validating RDF based knowledge graphs, can help. SHACL enables domain relevant structure, expre...

Gesture-controlled interfaces are becoming increasingly popular with the growing use of Internet of Things (IoT) systems. In particular, in automobiles, smart homes, computer games and Augmented Reality (AR)/Virtual Reality (VR) applications, gestures have become prevalent due to their accessibility to everyone. Designers, producers, and vendors in...

Knowledge sharing in forums is an important part of MOOCs (Massive Open Online Courses). However, the usage of forums to practice knowledge sharing are often inactive and inadequate. To address this problem, we used an action research to build and test a real-time sharing-quality-monitoring mechanism which assesses the quality of answers from text...

Linked Open Data promises to provide guiding principles to publish interlinked knowledge graphs on the Web in the form of findable, accessible, interoperable, and reusable datasets. We argue that while as such, Linked Data may be viewed as a basis for instantiating the FAIR principles, there are still a number of open issues that cause significant...

Ontologies have been used on the Web to enable semantic interoperability between parties that publish information independently of each other. They have also played an important role in the emergence of Linked Data. However, many ontologies on the Web do not see much use beyond their initial deployment and purpose in one dataset and therefore shoul...

In this paper, we present an OWL-based ontology, the Cloud Computing Ontology (CoCoOn), that defines concepts, features, attributes and relations to describe Cloud infrastructure services. We also present datasets that are built using CoCoOn and scripts (i.e. SPARQL template queries and web applications) that demonstrate the real-world applicabilit...

This book constitutes the refereed proceedings of the 16th International Semantic Web Conference, ESWC 2019, held in Portorož, Slovenia. The 39 revised full papers presented were carefully reviewed and selected from 134 submissions. The papers are organized in three tracks: research track, resources track, and in-use track and deal with the followi...

The joint W3C (World Wide Web Consortium) and OGC (Open Geospatial Consortium) Spatial Data on the Web (SDW) Working Group developed a set of ontologies to describe sensors, actuators, samplers as well as their observations, actuation, and sampling activities. The ontologies have been published both as a W3C recommendation and as an OGC implementat...

The Sensor, Observation, Sample, and Actuator (SOSA) ontology provides a formal but lightweight general-purpose specification for modellingthe interaction between the entities involved in the acts of observation, actuation, and sampling. SOSA is the result of rethinking the W3C-XG Semantic Sensor Network (SSN) ontology based on changes in scope and...

University courses provided online in form of MOOCs (Massive Open Online Courses) are gaining increased attention, yet their pricing structure is rarely studied. MOOCs can be treated as knowledge products, and MOOC platforms, therefore, become the marketplace for market-participants to trade those products. A functional knowledge market cannot be e...

The Sensor, Observation, Sample, and Actuator (SOSA) ontology provides a formal but lightweight general-purpose specification for modeling the interaction between the entities involved in the acts of observation, actuation, and sampling. SOSA is the result of rethinking the W3C-XG Semantic Sensor Network (SSN) ontology based on changes in scope and...

Motivation: Searching for precise terms and terminological definitions in the biomedical data space is problematic, as researchers find overlapping, closely related and even equivalent concepts in a single or multiple ontologies. Search engines that retrieve ontological resources often suggest an extensive list of search results for a given input...

The joint W3C (World Wide Web Consortium) and OGC (Open Geospatial Consortium) Spatial Data on the Web (SDW) Working Group developed a set of ontologies to describe sensors, actuators, samplers as well as their observations, actuation, and sampling activities. The ontologies have been published both as a W3C recommendation and as an OGC implementat...

The Sensor, Observation, Sample, and Actuator (SOSA) ontology provides a formal but lightweight general-purpose specification for modeling the interaction between the entities involved in the acts of observation, actuation, and sampling. SOSA is the result of rethinking the W3C-XG Semantic Sensor Network (SSN) ontology based on changes in scope and...

Data owners are creating an ever richer set of information resources online, and these are being used for more and more applications. Spatial data on the Web is becoming ubiquitous and voluminous with the rapid growth of location-based services, spatial technologies, dynamic location-based data and services published by different organizations. How...

Welcome to this special issue of the Future Generation Computer Systems (FGCS) journal. The special issue compiles seven technical contributions that significantly advance the state-of-the-art in exploration of Internet of Things (IoT) generated big data using semantic web techniques and technologies.

The Semantic Sensor Network (SSN) ontology is an ontology for describing sensors and their observations, the involved procedures, the studied features of interest, the samples used to do so, and the observed properties, as well as actuators. SSN follows a horizontal and vertical modularization architecture by including a lightweight but self-contai...

Ontology search is becoming increasingly important as the number of available ontologies on the Web steadily increases. Ontology recommendation is done by analyzing various properties of ontologies, such as syntax, structure, and usage, to find and recommend high-quality matches for a user defined query. Only a few ontology libraries and search eng...

In 2012 the Australian Bureau of Meteorology published a dataset, ACORN-SAT, containing the homogenised daily temperature observations of 112 locations throughout Australia for the last 100 years. The dataset employs the latest analysis techniques and takes advantage of newly digitised observational data to monitor climate variability and change in...

With the recent growth of Linked Data on the Web there is an increased need for knowledge engineers to find ontologies to describe their data. Only limited work exists that addresses the problem of searching and ranking ontologies based on a given query term. In this paper we introduce DWRank, a two-staged bi-directional graph walk ranking algorith...

Tables in documents are a rich source of information, but not yet well-utilised computationally because of the difficulty of extracting their structure and data automatically. In this paper, we progress the state-of-the-art in automatic table extraction by identifying common patterns in table headers to develop rules and heuristics for determining...

The Semantic Web provides access to an increasing amount of structured information in a wide variety of domains. Information overload due to the large amount of structured data is as much a problem as on the traditional Web. To solve this problem, ample research has been proposed on Semantic Web data retrieval techniques and after more than a decad...

This book constitutes the revised selected papers of the combined workshops on Web Information Systems Engineering, WISE 2014, held in Thessaloniki, Greece, in October 2014. The 19 selected papers presented were carefully revised and report from the four workshops: computational social networks, IWCSN 2014, enterprise social networks, Org2 2014, pe...

With the recent growth of Linked Data on the Web there is an increased need for knowledge engineers to find ontologies to describe their data. Only limited work exists that addresses the problem of searching and ranking ontologies based on a given query term. In this paper we introduce DWRank, a two-staged bi-directional graph walk ranking algorith...

Much of the recent work in Semantic Search is concerned with addressing the challenge of finding entities in the growing Web of Data. However, alongside this growth, there is a significant increase in the availability of ontologies that can be used to describe these entities. Whereas several methods have been proposed in Semantic Search to rank ent...

A growing number of approaches and tools have been utilised attempting at generating hypertext content with embedded metadata. However, little work has been carried out on finding a generic solution for publishing and styling Web pages with annotations derived from existing RDF data sets available in various formats. This paper proposes a metadata-...

With the advent of Linked Data the amount of automatically generated machine-readable data on the Web, often obtained by means of mapping relational data to RDF, has risen significantly. However, manually created, quality-assured and crowd-sourced data based on ontologies is not available in the quantities that would realise the full potential of t...

The effort over more than a decade to establish the semantic web [Berners-Lee et. al., 2001] has received a major boost in recent years through the Open Government movement. Governments around the world are seeking technical solutions to enable more open and transparent access to Public Sector Information (PSI) they hold. Existing technical protoco...

A recent trend in a number of academic disciplines is the publication of results of experiments together with the scientific article for a better reproducibility of the published experiments and algorithms. Semantic Web technologies have the potential to aid scientists in the publishing, sharing and interlinking of this data and also in helping oth...

This book constitutes the revised selected papers of the combined workshops on Web Information Systems Engineering, WISE 2011 and WISE 2012, held in Sydney, Australia, in October 2011 and in Paphos, Cyprus, in November 2012. The seven workshops of WISE 2011-2012 have reported the recent developments and advances in the contemporary topics in the re...

The Cloud infrastructure services landscape advances steadily leaving users in the agony of choice. As a result, Cloud service identification and discovery remains a hard problem due to different service descriptions, non standardised naming conventions and heterogeneous types and features of Cloud services. In this paper, we present an OWL based o...

The compass of Cloud infrastructure services advances steadily leaving users in the agony of choice. To be able to select the best mix of service offering from an abundance of possibilities, users must consider complex dependencies and heterogeneous sets of criteria. Therefore, we present a PhD thesis proposal on investigating an intelligent decisi...

The cloud infrastructure services landscape advances steadily leaving users in the agony of choice. Therefore, we present CloudRecommender, a new declarative approach for selecting Cloud-based infrastructure services. CloudRecommender automates the mapping of users’ specified application requirements to cloud service configurations. We formally cap...

The continuous growth of the Linked Data Web brings us closer to the original vision of the Web as an interconnected network of machine-readable resources. There is, however, an essential aspect in principle still missing from this vision, i.e., the ability for the Web user to interact directly with the Linked Data in a read/write manner. In this p...

The Australian Bureau of Meteorology (BOM) has recently published a homogenised daily temperature dataset, ACORN-SAT, for the monitoring of climate variability and change in Australia. The dataset employs the latest analysis techniques and takes advantage of newly digitised observational data to provide a daily temperature record over the last 100...

The continuous growth of the Linked Data Web brings us closer to the original vision of the Web, as an interconnected network of machine-readable resources. However, the ability to easily manipulate Linked Open Data (LOD) is still an open issue. In this demonstration we will show through a lifecycle model how to enable a domain-agnostic read/write...

In this work we construct partial order plans from a pool of atomic services described in OWL-S. We make extensions to Partial Order Planning to allow multiple conditional effects in action definitions. The purpose is to handle the uncertain behavior of Web services with incomplete initial information. We post-process the partial order plan to auto...

We propose an RDF-based user interface language called RaUL and a RESTful service called ActiveRaUL that interprets the language and produces XHTML+RDFa in return. The RaUL markup language separates the purpose (data publishing) of a Semantic Web form from its presentation. ActiveRaUL operates and generates RaUL markup, that separates the control e...

In this paper we introduce RaUL, the RDFa User Interface Language, a user interface markup ontology that is used to describe the structure of a web form as RDF statements. RaUL separates the markup of the control elements on a web form, the form model, from the data model that the form controls operate on. Form controls and the data model are conne...

We propose a change management framework for Service-Oriented Enterprise (SOEs). We present a taxonomy of changes that occur in SOEs, whereby we focus on bottom-up changes. We use a combination of Ordinary Petri nets and Reconfigurable Petri nets to model the triggering changes and reactive changes, respectively. We propose an automatic change mana...

Workflow models have been used and refined for years to execute processes within organisations. To deal with collaborative processes (choreographies) these internal work- flow models have to be aligned with the external behaviour advertised through Web service interfaces. However, traditional workflow management systems (WfMS) do not offer this fun...

In this paper we propose a new kind of adaptability assessment that determines whether service protocols of a requestor and a provider are adaptable, computes their adaptation degree, and identifies conditions that determine when they can be adapted. We also propose a technique that implements this adaptability assessment: (1) we construct a comple...

A continuous evolution of business process parameters, constraints and needs, hardly foreseeable initially, requires a continuous design from the business process management systems. In this article we are interested in developing a reactive design through process log analysis ensuring process re-engineering and execution reliability. We propose to...

Cross-organisational interoperability is a key issue for suc- cess in B2B e-commerce applications. To achieve this interoperability, choreography descriptions are necessary that describe how the business partners can cooperate. In existing approaches, these choreography de- scriptions are independent of the internal workflows of the partners. We pr...

This paper presents initial results on oXPDL, a process interchange ontology based on the standardised XML Process Definition Language (XPDL). XPDL was introduced to allow process model exchange between information systems, most of which are based on proprietary workflow models. Our process interchange ontology oXPDL explicitly models the complete...

This paper presents oXPDL, a process interchange ontology based on the stan- dardised XML Process Definition Language (XPDL). XPDL was introduced to allow pro- cess model exchange between information systems, most of which are based on proprietary workflow models. In its current form, XPDL allows only syntactic vendor-specific exten- sions without...

This paper presents a methodology to derive a Supply Chain Management Ontology based on the RosettaNet speciflca- tion framework. A prototype to mechanically derive a core ontology spanning all new Partner Interface Processes in the RosettaNet framework is developed and its algorithms to reconcile the ontology structure and to generate a proper sub...

RosettaNet is an industry-driven e-business process standard that defines common inter-company public processes and their associated business documents. RosettaNet is based on the Service-Oriented Architecture (SOA) paradigm and all business documents are expressed in DTD or XML Schema. Our "ontologically-enhanced RosettaNet" effort translates Rose...

A continuous evolution of business process parameters, constraints and needs, hardly foreseeable initially, requires from the business process management systems a continuous design and a reliable process model. In this paper, we are interested in developing a reactive design through a process log analysis ensuring process re-engineering and execut...

The Semantic Web application framework extends Ruby on Rails to enable rapid development of integrated Semantic Web mash-ups. Web applications are mostly database driven. Developers design a database schema and then construct the application logic (which generates Web pages for user interaction) on top of the schema. These applications are centrali...

Modeling the semantics of business services and their corresponding messages using ontologies enables flexible integration that is more adaptive to business-driven change. In this paper we demonstrate our approach building upon an established semantic Web service framework (WSMX) to facilitate a conversation between heterogeneous services that supp...

Object-oriented programming is the current mainstream pro- gramming paradigm but existing RDF APIs are mostly triple- oriented. Traditional techniques for bridging a similar gap between relational databases and object-oriented programs cannot be applied directly given the dierent nature of Se- mantic Web data, for example in the semantics of class...

We present a semantic B2B gateway based on the WSMX se- mantic Service-Oriented Architecture to tackle heterogenei- ties in RosettaNet messages. We develop a rich RosettaNet ontology and use the axiomatised knowledge and rules to resolve data heterogeneities and to unify unit conversions. We use adaptive executable choreography definitions to eas-...