The Mobile Semantic Web
Half-day tutorial at WWW 2014, Seul, Korea

Shonali Krishnaswamy1, Yuan-Fang Li2

1 Data Analytics Department, Institute for Infocomm Research (I2R), Singapore
spkrishna AT
2 Faculty of IT, Monash University, Australia AT

Abstract. The combination of the versatility of smart devices and the capabilities of semantic technologies forms a great foundation for a mobile Semantic Web that will contribute to further realizing the true potential of both disciplines. Motivated by a service discovery and matchmaking example, this tutorial provides an overview of background knowledge in ontology languages and basic reasoning problems, and how they are applicable in the mobile environment. It then presents challenges and state-of-the-art development on mobile ontology reasoning, focusing on the reasoning and optimization techniques developed in the mTableaux framework. Finally, the tutorial closes with an outlook of important research problems.

Update: Slides are available now!

  1. Motivation

    After more than a decade of active research, tremendous progress has been made in ontology reasoning, a core service for the Semantic Web, witnessed by the development of high-performance algorithms and tools. The recent explosive growth and the wide availability of smart devices bring us closer to realizing the potential synergy of the Semantic Web and ubiquitous computing. However, ontology reasoning in the mobile setting is an emerging research area and it has not been adequately addressed.

    This half-day tutorial aims to:

    • motivate the application of Semantic Web technologies in ubiquitous computing,
    • provide a comprehensive overview of the state-of-the-art research in both domains,
    • present existing research in ontology reasoning on mobile platforms, and
    • discuss research challenges and potential approaches to some of these challenges.

    Directly addressing two research topics of WWW 2014 (Semantic Web and User interfaces, human factors, and mobile devices), this timely tutorial will appeal to a broad audience, including both researchers and practitioners, and serve as a catalyst for kickstarting research on the mobile Semantic Web.

  2. Overview

    The recent years have witnessed an explosive growth of smart devices, with the iOS and Android being two leading platforms. Collectively iOS and Android dominate the smart devices market, accounting for almost 90% of the market share (calculated by units shipped) as of November 2012.

    Typically equipped with a comprehensive operating system, versatile connectivity options, rich multimedia support, various sensing capabilities and generous computational resources, smart devices has truly enabled ubiquitous and situation-aware communication. We believe it is an area of tremendous growth potential for the adoption of semantic technologies.

    Ontology reasoning is a core service for Semantic Web applications. Reasoning ensures the logical consistency of ontologies and infers implicit knowledge encoded in ontologies. After more than a decade of active research, tremendous progress has been made in ontology reasoning. Highly optimized reasoning algorithms have been invented for different OWL species and profiles. These include tableau algorithms for the expressive OWL 1 DL, hypertableau algorithms for the very expressive OWL 2 DL, and completion rules-based algorithms for the simpler OWL 2 EL, to name a few. Based on these algorithms, a number of efficient reasoners have been developed, including FaCT++, Pellet, HermiT, CEL and ELK.

    Smart devices usually have much more constrained computing power. Hence, ontology reasoning becomes an even more challenging problem on such devices. This tutorial will provide a landscape view of the existing reasoning techniques and present recent research on enabling efficient ontology reasoning on mobile devices.

  3. Aims

    The combination of improved computing capability and versatility of smart devices and the richness of data and software of the Semantic Web forms a great foundation for a mobile Semantic Web that will fully realize the true potential of both disciplines. This tutorial presents the state-of-the-art development in mobile and semantic technologies and outlines opportunities and challenges of ontology reasoning in a mobile setting.

  4. Prerequisite

    We assume the audience will have a basic knowledge of the Semantic Web. Knowledge of main languages (RDF and OWL) and ontology reasoning is advantageous but not required.

  5. Preliminary Tutorial Outline

    Introduction and motivation (30 minutes)

    1. Overview of tutorial
    2. A basic introduction to the Semantic Web & ubiquitous computing
    3. A motivating example: mobile service discovery & matchmaking
    4. Challenges of ontology reasoning and sources of complexity

    A brief introduction to ontology languages & reasoning (60 minutes)

    1. Ontology languages & the underlying description logics
    2. Overview of main reasoning approaches, tableau, hypertableau and completion rules-based algorithms

    Coffee break (30 minutes)

    Mobile ontology reasoning (70 minutes)

    1. Disussion on existing research in mobile ontology reasoning
    2. mTableaux - optimising tableaux for mobile semantic reasoning
      • Reasoning & optimisation techniques
      • Performance evaluation

    Conclusions, directions & discussions (15 minutes)

  6. Expected outcomes

    • An appreciation of the fundamental premise of the Semantic Web,
    • A good understanding of core reasoning problems on the Web Ontology Language OWL and OWL 2, and the underlying description logics,
    • An appreciation of challenges of applying semantic technologies in the mobile setting,
    • In-depth knowledge of current research that addresses the above challenges,
    • Familiarity with important and frequently-used algorithms, tools and datasets, and
    • Outlook on important future research problems.
  7. Presenters

    Shonali Krishnaswamy

    Shonali Krishnaswamy is an Associate Professor at the Faculty of Information Technology at Monash University, Australia and also Head, Data Analytics Department at Institute for Infocomm Research (I2R), Singapore. Her research interests include ontology reasoning and data stream mining in mobile and embedded environments, distributed data mining and web services/service oriented computing (where her focus is on quality of service and reputation models). More information is available at

    Yuan-Fang Li

    Yuan-Fang Li is currently a Lecturer at the Faculty of Information Technology at Monash University, Australia. He received both his Bachelor of Computing (with honors) and PhD degrees from National University of Singapore in 2002 and 2006, respectively. His main research interests include the Semantic Web (ontology languages, semantic query & inference, knowledge representation, data management) and software engineering (formal methods & verification, software metrics, software product line). More information is available at

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