Machine Reasoning Explainability

Total Page:16

File Type:pdf, Size:1020Kb

Machine Reasoning Explainability Machine Reasoning Explainability Kristijonas Cyrasˇ ,* Ramamurthy Badrinath, Swarup Kumar Mohalik, Anusha Mujumdar, Alexandros Nikou, Alessandro Previti, Vaishnavi Sundararajan, Aneta Vulgarakis Feljan Ericsson Research December 2, 2020 Abstract As a field of AI, Machine Reasoning (MR) uses largely symbolic means to formalize and emulate abstract reasoning. Studies in early MR have notably started inquiries into Explainable AI (XAI) – arguably one of the biggest concerns today for the AI community. Work on explain- able MR as well as on MR approaches to explainability in other areas of AI has continued ever since. It is especially potent in modern MR branches such as argumentation, constraint and logic programming, and planning. We hereby aim to provide a selective overview of MR explainability techniques and studies in hopes that insights from this long track of research will complement well the current XAI landscape. *Corresponding author. Email: [email protected], ORCiD: 0000-0002-4353-8121 arXiv:2009.00418v2 [cs.AI] 1 Dec 2020 1 K. Cyrasˇ et al. Machine Reasoning for Explainable AI Contents 1 Introduction 3 1.1 Contributions . .5 1.2 Motivations . .6 2 Explainability7 2.1 Purpose of Explanations . .8 2.2 Categorization for Explanations . .9 2.2.1 Attributive Explanations . 10 2.2.2 Contrastive Explanations . 12 2.2.3 Actionable Explanations . 15 3 Explanations in MR 16 3.1 Inference-based Explanations . 16 3.1.1 Axiom Pinpointing . 17 3.1.2 Implicants . 17 3.1.3 Abduction . 18 3.2 Logic Programming (LP) . 18 3.2.1 Abductive Logic Programming (ALP) . 19 3.2.2 Inductive Logic Programming (ILP) . 19 3.2.3 Answer Set Programming (ASP) . 20 3.3 Constraint Programming (CP) . 22 3.3.1 SAT and Beyond . 22 3.3.2 General CP . 24 3.4 Automated Theorem Proving (ATP) and Proof Assistants . 27 3.5 Argumentation . 29 3.5.1 Attributive/Contrastive argumentative explanations . 29 3.5.2 Actionable argumentative explanations . 32 3.5.3 Applications of argumentative explanations . 33 3.6 Planning . 33 3.7 Decision Theory . 36 3.8 Causal Approaches . 37 3.9 Symbolic Reinforcement Learning . 39 3.9.1 Constrained RL . 40 3.9.2 Multi-Agent RL (MARL) . 40 2 Ericsson Research K. Cyrasˇ et al. Machine Reasoning for Explainable AI 4 Discussion 40 4.1 Omissions . 41 4.2 Categorization-related Aspects . 42 4.3 Terminology . 44 5 Conclusions 46 1 Introduction Machine Reasoning (MR) is a field of AI that complements the field of Machine Learning (ML) by aiming to computationally mimic abstract thinking. This is done by way of uniting known (yet possibly incomplete) information with background knowledge and making inferences regarding un- known or uncertain information. MR has outgrown Knowledge Representation and Reasoning (KR, see e.g. [39]) and now encompasses various symbolic and hybrid AI approaches to automated reason- ing. Central to MR are two components: a knowledge base (see e.g. [83]) or a model of the problem (see e.g. [116]) , which formally represents knowledge and relationships among problem components in symbolic, machine-processable form; and a general-purpose inference engine or solving mecha- nism, which allows to manipulate those symbols and perform semantic reasoning.1 The field of Explainable AI (XAI, see e.g. [2, 21, 33, 73, 160, 179, 181, 188, 210, 222, 249]) encompasses endeavors to make AI systems intelligible to their users, be they humans or machines. XAI comprises research in AI as well as interdisciplinary research at the intersections of AI and subjects ranging from Human-Computer Interaction (HCI) [181] to social sciences [45, 177]. According to Hansen and Rieger[128], explainability was one of the main distinctions between the 1st wave (dominated by KR and rule-based systems) and the 2nd wave (expert systems and statisti- cal learning) of AI, with expert systems addressing the problems of explainability and ML approaches treated as black boxes. With the ongoing 3rd wave of AI, ML explainability has received a great surge of interest [21, 73, 181]. By contrast, it seems that a revived interest in MR explainability is only just picking up pace (e.g. ECAI 2020 Spotlight tutorial on Argumentative Explanations in AI2 and KR 2020 Workshop on Explainable Logic-Based Knowledge Representation3). However, explainability in MR dates over four decades [128, 139, 184, 188, 249] and can be roughly outlined thus. The 1st generation expert systems provide only so-called (reasoning) trace explanations, show- ing inference rules that led to a decision. A major problem with trace explanations is the lack of “information with respect to the system’s general goals and resolution strategy”[184, p. 174]. The 2nd generation expert systems instead provide so-called strategic explanations, “displaying system’s 1See [37] for an alternative view of MR stemming from a sub-symbolic/connectionist perspective. 2https://www.doc.ic.ac.uk/∼afr114/ecaitutorial/ 3https://lat.inf.tu-dresden.de/XLoKR20/ 3 Ericsson Research K. Cyrasˇ et al. Machine Reasoning for Explainable AI control behavior and problem-solving strategy.”[264, p. 95] Going further, so-called deep explana- tions separating the domain model from the structural knowledge have been sought, where “the sys- tem has to try to figure out what the user knows or doesn’t know, and try to answer the question taking that into account.”[259, p. 73] Progress in MR explainability notwithstanding, it has been ar- gued [169, 184, 210] that to date, explainability in MR particularly and perhaps in AI at large is still insufficient in aspects such as justification (“describing the rationale behind each inferential step taken by the system” [264, p. 95]), criticism, and cooperation. These aspects, among others, are of concern in the modern MR explainability scene (this millennium), whereby novel approaches to explainability in various branches of MR have been making appearances. Explainability is a highly desired aspect of autonomous agents and multi-agent systems (AA- MAS) [151, 160, 187]. There are a few area-specific reviews of explainability in AAMAS-related ar- eas: for instance [14] on human-robot interaction; [196] on expert and recommender systems; [222] on explaining ML agents; [59] on planning. However, explainability in multi-agent systems (MAS) is still under-explored [151, 160, 187]. In AI-equipped MAS (sometimes also called Distributed AI [164]), explainability concerns interactions among multiple intelligent agents, be they human or AI, to agree on and explain individual actions/decisions. Such interactions are often seen as a crucial driver for the real-world deployment of trustworthy modern AI systems. We will treat the following as a running example in Section2 to illustrate the kinds of explanations that we encounter in the XAI literature, including but not limited to MR approaches. Example 1.1. In modern software-defined telecommunication networks, network slicing is a means of running multiple logical networks on top of a shared physical network infrastructure [25]. Each logical network, i.e. a slice, is designed to serve a defined business purpose and comprises all the required network resources, configured and connected end-to-end. For instance, in a 5G network, a particular slice can be designated for high-definition video streaming. Such network slices are then to be managed—in the future, using autonomous AI-based agents—to consistently provide the desig- nated services. Service level agreements stipulate high-level intents that must be met, such as adequate quality of service, that translate into quantifiable performance indicators. An example of an intent is that end-to-end latency (from the application server to the end-user) should never exceed 25ms. Such intents induce lower level goals that AI-based agents managing the slice need to achieve. We consider the following agents to be involved in automatically managing the slice. When proac- tively monitoring adherence to intents, predictions of e.g. network latency are employed. So first, prediction of latency in the near future (say 20min interval) is done by an ML-based predictor agent based on previous network activity patterns (see e.g. [225]). Given a prediction of latency violation, the goal is to avoid it. To this end, a rule-based root cause analysis (RCA) agent needs to determine the most likely cause(s) of the latency violation which may, for instance, be a congested router port. Given a root cause, a constraint solver agent aims to find a solution to a network reconfiguration 4 Ericsson Research K. Cyrasˇ et al. Machine Reasoning for Explainable AI problem, say a path through a different data centre, that satisfies the slice requirements, including latency. Finally, a planner agent provides a procedural knowledge-based plan for execution of the reconfiguration (i.e. how to optimally relocate network resources). In all of the above phases, explainability of the AI-based agents is desirable. First and foremost, one may want to know which features contributed the most to the predicted latency violation. These may point to the performance measurement counter readings that via domain expert-defined rules lead to inferring the root cause. Explaining RCA by indicating the facts and rules that are necessary and sufficient to establish the root cause contributes to the overall explainability of handling intents. Orthogonally, the constraint solver may be unable to find a solution within the initial soft constraints, such as limited number of hops, whence the network reconfiguration problem unsolvability could be explained by indicating a set of mutually unsatisfiable constraints and suggesting a relaxation, such as increasing the number of hops. When some reconfiguration solution is found and the planner yields a plan for implementation, its goodness as well as various alternative actions and contrastive states may be considered for explainability purposes. Last but not least, the overall decision process needs to be explainable too, by for instance exhibiting the key considerations and weighing arguments for and against the best outcomes in all of the phases of prediction, RCA, solving and planning.
Recommended publications
  • A Logical Framework for Modularity of Ontologies∗
    A Logical Framework for Modularity of Ontologies∗ Bernardo Cuenca Grau, Ian Horrocks, Yevgeny Kazakov and Ulrike Sattler The University of Manchester School of Computer Science Manchester, M13 9PL, UK {bcg, horrocks, ykazakov, sattler }@cs.man.ac.uk Abstract ontology itself by possibly reusing the meaning of external symbols. Hence by merging an ontology with external on- Modularity is a key requirement for collaborative tologies we import the meaning of its external symbols to de- ontology engineering and for distributed ontology fine the meaning of its local symbols. reuse on the Web. Modern ontology languages, To make this idea work, we need to impose certain con- such as OWL, are logic-based, and thus a useful straints on the usage of the external signature: in particular, notion of modularity needs to take the semantics of merging ontologies should be “safe” in the sense that they ontologies and their implications into account. We do not produce unexpected results such as new inconsisten- propose a logic-based notion of modularity that al- cies or subsumptions between imported symbols. To achieve lows the modeler to specify the external signature this kind of safety, we use the notion of conservative exten- of their ontology, whose symbols are assumed to sions to define modularity of ontologies, and then prove that be defined in some other ontology. We define two a property of some ontologies, called locality, can be used restrictions on the usage of the external signature, to achieve modularity. More precisely, we define two no- a syntactic and a slightly less restrictive, seman- tions of locality for SHIQ TBoxes: (i) a tractable syntac- tic one, each of which is decidable and guarantees tic one which can be used to provide guidance in ontology a certain kind of “black-box” behavior, which en- editing tools, and (ii) a more general semantic one which can ables the controlled merging of ontologies.
    [Show full text]
  • Deciding Semantic Matching of Stateless Services∗
    Deciding Semantic Matching of Stateless Services∗ Duncan Hull†, Evgeny Zolin†, Andrey Bovykin‡, Ian Horrocks†, Ulrike Sattler†, and Robert Stevens† School of Computer Science, Department of Computer Science, † ‡ University of Manchester, UK University of Liverpool, UK Abstract specifying automated reasoning algorithms for such stateful service descriptions is basically impossible in the presence We present a novel approach to describe and reason about stateless information processing services. It can of any expressive ontology (Baader et al. 2005). Stateless- be seen as an extension of standard descriptions which ness implies that we do not need to formulate pre- and post- makes explicit the relationship between inputs and out- conditions since our services do not change the world. puts and takes into account OWL ontologies to fix the The question we are interested in here is how to help the meaning of the terms used in a service description. This biologist to find a service he or she is looking for, i.e., a allows us to define a notion of matching between ser- service that works with inputs and outputs the biologist can vices which yields high precision and recall for service provide/accept, and that provides the required functionality. location. We explain why matching is decidable, and The growing number of publicly available biomedical web provide biomedical example services to illustrate the utility of our approach. services, 3000 as of February 2006, required better match- ing techniques to locate services. Thus, we are concerned with the question of how to describe a service request Q Introduction and service advertisements Si such that the notion of a ser- Understanding the data generated from genome sequenc- vice S matching the request Q can be defined in a “useful” ing projects like the Human Genome Project is recognised way.
    [Show full text]
  • ANDREAS PIERIS School of Informatics, University of Edinburgh 10 Crichton Street, Edinburgh, EH8 9AB, UK [email protected]
    ANDREAS PIERIS School of Informatics, University of Edinburgh 10 Crichton Street, Edinburgh, EH8 9AB, UK [email protected] UNIVERSITY EDUCATION • D.Phil. in Computer Science, 2011 Department of Computer Science, University of Oxford Thesis: Ontological Query Answering: New Languages, Algorithms and Complexity Supervisor: Professor Georg Gottlob • M.Sc. in Mathematics anD FounDations oF Computer Science (with Distinction), 2007 Mathematical Institute, University of Oxford Thesis: Data Exchange and Schema Mappings Supervisor: Professor Georg Gottlob • B.Sc. in Computer Science (with Distinction, GPA: 9.06/10), 2006 Department of Computer Science, University of Cyprus Thesis: The Fully Mixed Nash Equilibrium Conjecture Supervisor: Professor Marios Mavronicolas EMPLOYMENT HISTORY • Lecturer (equivalent to Assistant ProFessor) in Databases, 09/2016 – present School of Informatics, University of Edinburgh • PostDoctoral Researcher, 11/2014 – 09/2016 Institute of Logic and Computation, Vienna University of Technology • PostDoctoral Researcher, 09/2011 – 10/2014 Department of Computer Science, University of Oxford RESEARCH Major research interests • Data management: knowledge-enriched data, uncertain data • Knowledge representation and reasoning: ontology languages, complexity of reasoning • Computational logic and its applications to computer science Research grants • EfFicient Querying oF Inconsistent Data, 09/2018 – 08/2022 Principal Investigator Funding agency: Engineering and Physical Sciences Research Council (EPSRC) Total award: £758,049 • Value AdDeD Data Systems: Principles anD Architecture, 04/2015 – 03/2020 Co-Investigator Funding agency: Engineering and Physical Sciences Research Council (EPSRC) Total award: £1,546,471 Research supervision experience • Marco Calautti, postdoctoral supervision, University of Edinburgh, 09/2016 – present • Markus Schneider, Ph.D. supervisor, University of Edinburgh, 09/2018 – present • Gerald Berger, Ph.D.
    [Show full text]
  • Ontology-Based Methods for Analyzing Life Science Data
    Habilitation a` Diriger des Recherches pr´esent´ee par Olivier Dameron Ontology-based methods for analyzing life science data Soutenue publiquement le 11 janvier 2016 devant le jury compos´ede Anita Burgun Professeur, Universit´eRen´eDescartes Paris Examinatrice Marie-Dominique Devignes Charg´eede recherches CNRS, LORIA Nancy Examinatrice Michel Dumontier Associate professor, Stanford University USA Rapporteur Christine Froidevaux Professeur, Universit´eParis Sud Rapporteure Fabien Gandon Directeur de recherches, Inria Sophia-Antipolis Rapporteur Anne Siegel Directrice de recherches CNRS, IRISA Rennes Examinatrice Alexandre Termier Professeur, Universit´ede Rennes 1 Examinateur 2 Contents 1 Introduction 9 1.1 Context ......................................... 10 1.2 Challenges . 11 1.3 Summary of the contributions . 14 1.4 Organization of the manuscript . 18 2 Reasoning based on hierarchies 21 2.1 Principle......................................... 21 2.1.1 RDF for describing data . 21 2.1.2 RDFS for describing types . 24 2.1.3 RDFS entailments . 26 2.1.4 Typical uses of RDFS entailments in life science . 26 2.1.5 Synthesis . 30 2.2 Case study: integrating diseases and pathways . 31 2.2.1 Context . 31 2.2.2 Objective . 32 2.2.3 Linking pathways and diseases using GO, KO and SNOMED-CT . 32 2.2.4 Querying associated diseases and pathways . 33 2.3 Methodology: Web services composition . 39 2.3.1 Context . 39 2.3.2 Objective . 40 2.3.3 Semantic compatibility of services parameters . 40 2.3.4 Algorithm for pairing services parameters . 40 2.4 Application: ontology-based query expansion with GO2PUB . 43 2.4.1 Context . 43 2.4.2 Objective .
    [Show full text]
  • Description Logics
    Description Logics Franz Baader1, Ian Horrocks2, and Ulrike Sattler2 1 Institut f¨urTheoretische Informatik, TU Dresden, Germany [email protected] 2 Department of Computer Science, University of Manchester, UK {horrocks,sattler}@cs.man.ac.uk Summary. In this chapter, we explain what description logics are and why they make good ontology languages. In particular, we introduce the description logic SHIQ, which has formed the basis of several well-known ontology languages, in- cluding OWL. We argue that, without the last decade of basic research in description logics, this family of knowledge representation languages could not have played such an important rˆolein this context. Description logic reasoning can be used both during the design phase, in order to improve the quality of ontologies, and in the deployment phase, in order to exploit the rich structure of ontologies and ontology based information. We discuss the extensions to SHIQ that are required for languages such as OWL and, finally, we sketch how novel reasoning services can support building DL knowledge bases. 1 Introduction The aim of this section is to give a brief introduction to description logics, and to argue why they are well-suited as ontology languages. In the remainder of the chapter we will put some flesh on this skeleton by providing more technical details with respect to the theory of description logics, and their relationship to state of the art ontology languages. More detail on these and other matters related to description logics can be found in [6]. Ontologies There have been many attempts to define what constitutes an ontology, per- haps the best known (at least amongst computer scientists) being due to Gruber: “an ontology is an explicit specification of a conceptualisation” [47].3 In this context, a conceptualisation means an abstract model of some aspect of the world, taking the form of a definition of the properties of important 3 This was later elaborated to “a formal specification of a shared conceptualisation” [21].
    [Show full text]
  • Proceedings of the 11Th International Workshop on Ontology
    Proceedings of the 11th International Workshop on Ontology Matching (OM-2016) Pavel Shvaiko, Jérôme Euzenat, Ernesto Jiménez-Ruiz, Michelle Cheatham, Oktie Hassanzadeh, Ryutaro Ichise To cite this version: Pavel Shvaiko, Jérôme Euzenat, Ernesto Jiménez-Ruiz, Michelle Cheatham, Oktie Hassanzadeh, et al.. Proceedings of the 11th International Workshop on Ontology Matching (OM-2016). Ontology matching workshop, Kobe, Japan. No commercial editor., pp.1-252, 2016. hal-01421835 HAL Id: hal-01421835 https://hal.inria.fr/hal-01421835 Submitted on 15 Jul 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Ontology Matching OM-2016 Proceedings of the ISWC Workshop Introduction Ontology matching1 is a key interoperability enabler for the semantic web, as well as a useful tactic in some classical data integration tasks dealing with the semantic hetero- geneity problem. It takes ontologies as input and determines as output an alignment, that is, a set of correspondences between the semantically related entities of those on- tologies. These correspondences can be used for various tasks, such as ontology merg- ing, data translation, query answering or navigation on the web of data. Thus, matching ontologies enables the knowledge and data expressed in the matched ontologies to in- teroperate.
    [Show full text]
  • Justification Oriented Proofs In
    Justification Oriented Proofs in OWL Matthew Horridge, Bijan Parsia, and Ulrike Sattler School of Computer Science, The University of Manchester Abstract. Justifications — that is, minimal entailing subsets of an on- tology — are currently the dominant form of explanation provided by ontology engineering environments, especially those focused on the Web Ontology Language (OWL). Despite this, there are naturally occurring justifications that can be very difficult to understand. In essence, justifi- cations are merely the premises of a proof and, as such, do not articulate the (often non-obvious) reasoning which connect those premises with the conclusion. This paper presents justification oriented proofs as a poten- tial solution to this problem. 1 Introduction and Motivation Modern ontology development environments such as Prot´eg´e-4, the NeOn Toolkit, Swoop, and Top Braid Composer, allow users to request explanations for entail- ments (inferences) that they encounter when editing or browsing ontologies. In- deed, the provision of explanation generating functionality is generally seen as being a vital component in such tools. Over the last few years, justifications have become the dominant form of explanation in these tools. This paper examines justifications as a kind of explanation and highlights some problems with them. It then presents justification lemmatisation as a non-standard reasoning service, which can be used to augment a justification with intermediate inference steps, and gives rise to a structure known as a justification oriented proof. Ultimately, a justification oriented proof could be used as an input into some presentation de- vice to help a person step though a justification that is otherwise too difficult for them to understand.
    [Show full text]
  • Toward an Open Knowledge Research Graph.Pdf
    THE SERIALS LIBRARIAN https://doi.org/10.1080/0361526X.2019.1540272 Toward an Open Knowledge Research Graph Sören Auera and Sanjeet Mann b aPresenter; bRecorder ABSTRACT KEYWORDS Knowledge graphs facilitate the discovery of information by organizing it into Knowledge graph; scholarly entities and describing the relationships of those entities to each other and to communication; Semantic established ontologies. They are popular with search and e-commerce com- Web; linked data; scientific panies and could address the biggest problems in scientific communication, research; machine learning according to Sören Auer of the Technische Informationsbibliothek and Leibniz University of Hannover. In his NASIG vision session, Auer introduced attendees to knowledge graphs and explained how they could make scientific research more discoverable, efficient, and collaborative. Challenges include incentiviz- ing researchers to participate and creating the training data needed to auto- mate the generation of knowledge graphs in all fields of research. Change in the digital world Thank you to Violeta Ilik and the NASIG Program Planning Committee for inviting me to this conference. I would like to show you where I come from. Leibniz University of Hannover has a castle that belonged to a prince, and next to the castle is the Technische Informationsbibliothek (TIB), responsible for supporting the scientific and technology community in Germany with publications, access, licenses, and digital information services. Figure 1 is an example of a knowledge graph about TIB. The basic ingredients of a knowledge graph are entities and relationships. We are the library of Leibniz University of Hannover and we are a member of Leibniz Association (a German research association).
    [Show full text]
  • AAAI-11 Program Schedule.IAAI.EAAI
    AAAI-11 Technical Program Schedule Monday, August 8 6:00 – 7:00 pm AAAI-11 Opening Reception Tuesday, August 9 8:30 - 9:00 am Grand Ballroom, Street Level AAAI-11/IAAI-11 Opening Ceremony Welcome and Opening Remarks Outstanding Award Presentations -- Papers, SPC Member, PC Member Wolfram Burgard and Dan Roth, AAAI-11 Program Cochairs IAAI Welcome, Robert S. Engelmore Award, Deployed Application Award Announcements Daniel Shapiro, IAAI-11 Conference Chair, Markus Fromherz, IAAI-11 Program Cochair, and David Leake, AI Magazine Editor-in-Chief Feigenbaum Prize, AAAI Classic Paper Award, Distinguished Service Award Fellows Announcement, Senior Member Recognition Eric Horvitz, AAAI Past President and Awards Committee Chair Henry Kautz, AAAI President 9:15 – 10:00 am AAAI-11 25th Conference Anniversary Panel Moderator: Manuela Veloso, AAAI President-Elect (Carnegie Mellon University) 10:00 – 10:20 am Coffee Break 10:20 - 11:20 am IAAI-11/AAAI-11 Joint Invited Talk: Building Watson: An Overview of DeepQA for the Jeopardy! Challenge David Ferrucci (IBM T J Watson Research Center) 11:30 am – 12:30 pm Description Logics 1 281: Revisiting Semantics for Epistemic Extensions of Description Logics Anees Mehdi, Sebastian Rudolph 242: Integrating Rules and Description Logics by Circumscription Qian Yang, Jia-Huai You, Zhiyong Feng 626: Conjunctive Query Inseparability of OWL 2QL TBoxes B. Konev, R. Kontchakov, M. Ludwig, T. Schneider, F. Wolter, M. Zakharyaschev Machine Learning 1 6024: Nectar: Quantity Makes Quality: Learning with Partial Views Nicolò Cesa-Bianchi, Shai Shalev-Shwartz, Ohad Shamir 31: Symmetric Graph Regularized Constraint Propagation Zhenyong Fu, Zhiwu Lu, Horace H. S.
    [Show full text]
  • Curriculum Vitae
    Curriculum vitae Thomas Andreas Meyer 25 August 2019 Address Room 312, Computer Science Building University of Cape Town University Avenue, Rondebosch Tel: +27 12 650 5519 e-mail: [email protected] WWW: http://cs.uct.ac.za/~tmeyer Biographical information Date of birth: 14 January 1964, Randburg, South Africa. Marital status: Married to Louise Leenen. We have two children. Citizenship: Australian and South African. Qualifications 1. PhD (Computer Science), University of South Africa, Pretoria, South Africa, 1999. 2. MSc (Computer Science), Rand Afrikaans University (now the University of Johan- nesburg), Johannesburg, South Africa, 1986. 3. BSc Honours (Computer Science) with distinction, Rand Afrikaans University (now the University of Johannesburg), Johannesburg, South Africa, 1985. 4. BSc (Computer Science, Mathematical Statistics), Rand Afrikaans University (now the University of Johannesburg), Johannesburg, South Africa, 1984. 1 Employment and positions held 1. July 2015 to date: Professor, Department of Computer Science, University of Cape Town, Cape Town, South Africa. 2. July 2015 to June 2020: Director, Centre for Artificial Intelligence Research (CAIR), CSIR, Pretoria, South Africa. 3. July 2015 to June 2020: UCT-CSIR Chair in Artificial Intelligence, University of Cape Town, Cape Town, South Africa. 4. August 2011 to June 2015: Chief Scientist, CSIR Meraka Institute, Pretoria, South Africa. 5. May 2011 to June 2015: Director of the UKZN/CSIR Meraka Centre for Artificial Intelligence Research, CSIR and University of KwaZulu-Natal, South Africa. 6. August 2007 to July 2011: Principal Researcher, CSIR Meraka Institute, Pretoria, South Africa. 7. August 2007 to June 2015: Research Group Leader of the Knowledge Representation and Reasoning group (KRR) at the CSIR Meraka Institute, Pretoria, South Africa.
    [Show full text]
  • Internationale Mathematische Nachrichten
    INTERNATIONALE MATHEMATISCHE NACHRICHTEN INTERNATIONAL MATHEMATICAL NEWS NOUVELLES MATHEMA¶ TIQUES INTERNATIONALES NACHRICHTEN DER OSTERREICHISCHENÄ MATHEMATISCHEN GESELLSCHAFT EDITED BY OSTERREICHISCHEÄ MATHEMATISCHE GESELLSCHAFT Nr. 181 August 1999 WIEN INTERNATIONALE MATHEMATISCHE NACHRICHTEN INTERNATIONAL MATHEMATICAL NEWS NOUVELLES MATHEMA¶ TIQUES INTERNATIONALES GegrundetÄ 1947 von R. Inzinger, fortgefuhrtÄ von W. Wunderlich Herausgeber: OSTERREICHISCHEÄ MATHEMATISCHE GESELLSCHAFT Redaktion: P. Flor (U Graz; Herausgeber), U. Dieter (TU Graz), M. Drmota (TU Wien), L. Reich (U Graz) und J. Schwaiger (U Graz), unter stÄandiger Mit- arbeit von R. Mlitz (TU Wien) und E. Seidel (U Graz). ISSN 0020-7926. Korrespondenten DANEMARK:Ä M. E. Larsen (Dansk Matematisk Forening, Kopenhagen) FRANKREICH: B. Rouxel (Univ. Bretagne occ., Brest) GRIECHENLAND: N. K. Stephanidis (Univ. Saloniki) GROSSBRITANNIEN: The Institute of Mathematics and Its Applications (Southend-on-Sea), The London Mathematical Society JAPAN: K. Iseki¶ (Japanese Asoc. of Math. Sci) JUGOSLAWIEN: S. Pre·sic¶ (Univ. Belgrad) KROATIEN: M. Alic¶ (Zagreb) NORWEGEN: Norsk Matematisk Forening (Oslo) OSTERREICH:Ä C. Binder (TU Wien) RUMANIEN:Ä F.-K. Klepp (Timisoara) SCHWEDEN: Svenska matematikersamfundet (GÄoteborg) 2 SLOWAKEI: J. Sira· n· (Univ. Pre¼burg) SLOWENIEN: M. Razpet (Univ. Laibach) TSCHECHISCHE REPUBLIK: B. Maslowski (Akad. Wiss. Prag) USA: A. Jackson (Amer. Math. Soc., Providende RI) INTERNATIONALE MATHEMATISCHE NACHRICHTEN INTERNATIONAL MATHEMATICAL NEWS NOUVELLES MATHEMA¶
    [Show full text]
  • Conference Program
    Twenty-Fifth AAAI Conference on Artificial Intelligence (AAAI-11) Twenty-Third Conference on Innovative Applications of Artificial Intelligence (IAAI-11) Second Symposium on Educational Advances in Artificial Intelligence (EAAI-11) August 7 – 11, 2011 Hyatt Regency San Francisco San Francisco, California, USA Sponsored by the Association for the Advancement of Artificial Intelligence Cosponsored by the National Science Foundation, AI Journal, Google, Inc. Microsoft Research, Cornell University Institute for Computational Sustainability Naval Research Laboratory, Yahoo! Research Labs, NASA Ames Research Center University of Southern California/Information Sciences Institute, ACM/SIGART IBM Research, Videolectures.net, and David E. Smith Conference Program Acknowledgments Robotics Program Chair Contents The Association for the Advancement of Artifi- Andrea Thomaz (Georgia Institute of Technology, USA) cial Intelligence acknowledges and thanks the Acknowledgments / 2 following individuals for their generous contri- Poker Competition Cohairs AI Video Competition / 18 butions of time and energy to the successful Nolan Bard (University of Alberta, Canada) Awards / 2–4 creation and planning of the Twenty-Fifth AAAI Jonathan Rubin (University of Auckland, New Competitions / 18–19 Conference on Artificial Intelligence and the Zealand) Conference at a Glance / 5 Twenty-Third Conference on Innovative Appli- AI Video Competition Cochairs Doctoral Consortium / 8 cations of Artificial Intelligence. David Aha (Naval Research Laboratory, USA) EAAI-11 Program / 9 Arnav Jhala (University of California, Santa Cruz, Exhibition / 16 AAAI-11 Conference Committee USA) General Information / 20 IAAI-11 Program / 10–15 AAAI Conference Committee Chair A complete listing of the AAAI-11 / IAAI-11 / Invited Presentations / 3, 6–7 Dieter Fox (University of Washington, USA) EAAI-11 Program Committee members appears in Poker Competition / 18 AAAI-11 Program Cochairs the conference proceedings.
    [Show full text]