Nir Lipovetzky

Nir Lipovetzky

Senior Lecturer in Artificial Intelligence

The University of Melbourne

Biography

I am a Senior Lecturer in Artificial intelligencee at the School of Computing and Information Systems, The University of Melbourne. I’m a member of the Agent Lab group. I completed my PhD at the Artificial Intelligence and Machine Learning Group, Universitat Pompeu Fabra, under the supervision of Prof. Hector Geffner. I was a research fellow for 3 years under the supervision of Prof. Peter Stuckey and Prof. Adrian Pearce, working on solving Mining Scheduling problems through automated planning, constraint programming and operations research techniques.

My research focuses on how to introduce different approaches to the problem of inference in sequential decision problems, as well as applications to autonomous systems.

Interests

  • AI planning
  • Search
  • Learning
  • Verification
  • Constraint Programming
  • Operations Research
  • Intention Recognition
  • Sequential Decision Problems
  • Autonomous Systems

Education

  • PhD in Artificial Intelligence, 2012

    Universitat Pompeu Fabra

  • MEng in Artificial Intelligence, 2007

    Universitat Pompeu Fabra

  • BSc in Computer Science, 2004

    Universitat Pompeu Fabra

Recent News

All news»

[13/07/20] New paper on Boundary Extension Features for Width-Based Planning with Simulators on Continuous-State Domains, published@IJCAI-20.

[12/05/20] New paper on Goal Recognition Using Off-The-Shelf Process Mining Techniques, published@AAMAS-20.

[31/3/20] New Book Chapter on Planning.Domains published @ Knowledge Engineering Tools and Techniques for AI Planning (KEPS Book)

Projects

Width Based Planning

Width Based Planning searches for solutions through a general measure of state novelty. Performs well over black-box simulators and PDDL problems.

Planimation

Planimation is a framework to visualise sequential solutions of planning problems specified in PDDL

Classical Planners

Awarded top performance classical planners in serveral International Planning Competitions 2008 - 2019

Trapper

Invariants, Traps, Un-reachability Certificates, and Dead-end Detection

AI 4 Education

Software to support AI courses in Mel & RMIT Unis (Melbourne, AUS)

Arcade Learning Environment

Classical Planners playing Atari 2600 games as well as Deep Reinforcement Learning

Linear Temporal Logic, Planning and Synthesis

classical planners computing infinite loopy plans, and FOND planners synthesizing controllers expressed as policies.

LAPKT

Lightweight Automated Planning ToolKiT (LAPKT) to build, use or extend basic to advanced Automated Planners

Recent Publications

Quickly discover relevant content by filtering publications.

Assessment of Smoke Contamination in Grapevine Berries and Taint in Wines Due to Bushfires Using a Low-Cost E-Nose and an Artificial Intelligence Approach

Bushfires are increasing in number and intensity due to climate change. A newly developed low-cost electronic nose (e-nose) was tested on wines made from grapevines exposed to smoke in field trials. E-nose readings were obtained from wines from five experimental treatments: (i) low-density smoke exposure (LS), (ii) high-density smoke exposure (HS), (iii) high-density smoke exposure with in-canopy misting (HSM), and two controls: (iv) control (C; no smoke treatment) and (v) control with in-canopy misting (CM; no smoke treatment). These e-nose readings were used as inputs for machine learning algorithms to obtain a classification model, with treatments as targets and seven neurons, with 97% accuracy in the classification of 300 samples into treatments as targets (Model 1). Models 2 to 4 used 10 neurons, with 20 glycoconjugates and 10 volatile phenols as targets, measured: in berries one hour after smoke (Model 2; R = 0.98; R2 = 0.95; b = 0.97); in berries at harvest (Model 3; R = 0.99; R2 = 0.97; b = 0.96); in wines (Model 4; R = 0.99; R2 = 0.98; b = 0.98). Model 5 was based on the intensity of 12 wine descriptors determined via a consumer sensory test (Model 5; R = 0.98; R2 = 0.96; b = 0.97). These models could be used by winemakers to assess near real-time smoke contamination levels and to implement amelioration strategies to minimize smoke taint in wines following bushfires.

Boundary Extension Features for Width-Based Planning with Simulators on Continuous-State Domains

Width-based planning algorithms have been demonstrated to be competitive with state-of-the-art heuristic search and SAT-based approaches, without requiring access to a model of action effects and preconditions, just access to a black-box simulator. Width-based planners search is guided by a measure of the novelty of states, that requires observations on simulator states to be given as a set of features. This paper proposes agnostic feature mapping mechanisms that define the features online, as exploration progresses and the domain of continuous state variables is revealed. We demonstrate the effectiveness of these features on the OpenAI gym “classical control” suite of benchmarks. We compare our online planners with state-of-the-art deep reinforcement learning algorithms, and show that width-based planners using our features can find policies of the same quality with significantly less computational resources.

Goal Recognition Using Off-The-Shelf Process Mining Techniques

The problem of probabilistic goal recognition consists of automatically inferring a probability distribution over a range of possible goals of an autonomous agent based on the observations of its behavior. The state-of-the-art approaches for probabilistic goal recognition assume the full knowledge about the world the agent operates in and possible agent’s operations in this world. In this paper, we propose a framework for solving the probabilistic goal recognition problem using process mining techniques for discovering models that describe the observed behavior and diagnosing deviations between the discovered models and observations. The framework imitates the principles of observational learning, one of the core mechanisms of social learning exhibited by humans, and relaxes the above assumptions. It has been implemented in a publicly available tool. The reported experimental results confirm the effectiveness and efficiency of the approach, both for rational and irrational agents’ behaviors.

KEPS Book: Planning. Domains

In this chapter we describe the main pillars of the Planning.Domains initiative (API, Solver, Editor, and Education), detail some of the current use-cases for them, and outline the future path of the initiative. We further dive into some of the most recent developments of Planning.Domains, and shed light on what is next for the platform.

Best-First Width Search for Multi Agent Privacy-preserving Planning

In multi-agent planning, preserving the agents’ privacy has become an increasingly popular research topic. For preserving the agents’ privacy, agents jointly compute a plan that achieves mutual goals by keeping certain information private to the individual agents. Unfortunately, this can severely restrict the accuracy of the heuristic functions used while searching for solutions. It has been recently shown that, for centralized planning, the performance of goal oriented search can be improved by combining goal oriented search and width-based search. The combination of these techniques has been called best-first width search. In this paper, we investigate the usage of best-first width search in the context of (decentralised) multi-agent privacy-preserving planning, addressing the challenges related to the agents’ privacy and performance. In particular, we show that best-first width search is a very effective approach over several benchmark domains, even when the search is driven by heuristics that roughly estimate the distance from goal states, computed without using the private information of other agents. An experimental study analyses the effectiveness of our techniques and compares them with the state-of-the-art.

Students

Current Students

Ph.D.

  • Guang Hu [2020 - current], co-supervised with Dr.Tim Miller. Topic: Epistemic Planning and Explanability.

  • Zihang Su [2020 - current], co-supervised with Dr. Artem Polyvyanyy and Prof. Sebastian Sardina. Topic: Bridging the gap between Process Mining and Goal-Plan-Intention Recognition

  • Chenyuan Zhang [2020 - current], co-supervised with A/Prof. Charles Kemp (Psychology). Topic: Relaxations and Heuristics in Human Complex Problem Solving

  • Anubhav Singh [2019 - current], co-supervized with Dr. Miquel Ramirez. Topic: Planing with polynomial guarantees for bounded computational resources

  • Stefan O'Toole [2018 - current], co-supervized with Dr. Miquel Ramirez and Prof. Adrian Pearce. Topic: Bridging Planning and Reinforcement Learning over continous and discrete dynamics

Masters

  • Chao Lei [2019-current]. Topic: Regression in Classical Planning

Alumni

Ph.D.

  • Toby Davies, [2013-2017], co-supervized with Prof. Adrian Pearce, Prof. Peter Stuckey and Prof. Harald Sondergaard. Topic: Learning from Conflict in Multi-Agent, Classical, and Temporal Planning. First Employment: Google [2017 - current]. Best Paper Award ICAPS (2015), Best PhD Thesis, Melbourne School of Engineering 2018

Masters

  • Dmitry Grebenyuk [2018-2020], co-supervised with Dr. Miquel Ramirez, and Dr. Kris Ehinger. Topic: Agnostic Features for generalized policies computed with Deep Reinforcement Learning. First Employment: Start-up working on Image Processing using DRL.

  • Guang Hu [2018-2020], co-supervised with Dr.Tim Miller. Topic: What you get is what you see: Decomposing Epistemic Planning using Functional STRIPS.PhD Candidate [2020 - current]

Honours and Awards

Winner (PROBE planner) and Runner-up (BFWS planner)

Winner - Agile Track | Runner-up - Satisficing Track (BFWS planners)

Winner - Time Track | Runner-Up - Quality and Coverage tracks (LAPKT planners)

Best Dissertation Award (ICAPS)

Text of Award: Nir Lipovetzky takes a new, and very original, look at automated planning: how to reason your way to a plan, instead of searching (blindly or heuristically) for it. First, he has developed a range of novel inference techniques that, combined, produce classical planners that can work with very little backtracking – in many cases none at all – and perform well enough to be awarded at two IPCs. Second, he has invented a novel measure of the hardness of a planning problem, called “width”, and has shown that by properly exploiting it, a simple blind search can do as well as the best-performing heuristic search planners.

Service

Program Chair

  • International Conference on Automated Planning and Scheduling, ICAPS (2019)

Organizing Committee

  • International Conference on Automated Planning and Scheduling – Publicity co-chair, ICAPS (2010)

  • First Unsolvability International Planning Competition – Co-Organizer, UIPC-1 (2016)

  • Heuristics and Search for Domain-independent Planning – Co-Organizer, ICAPS workshop HSDIP (2015,2016,2017,2018)

  • Student Abstract track – Co-Chair, AAAI (2018,2019)

  • Journal Presentation track – Co-Chair ICAPS (2018)

Senior Programme Committee

  • Association for the Advancement of Artificial Intelligence, AAAI (2020)

Programme Committee

  • International Joint Conferences on Artificial Intelligence IJCAI (2011,2013,2015,2017,2018,2020)

  • Association for the Advancement of Artificial Intelligence, AAAI (2013,2015,2016,2017,2018,2019)

  • European Conference on Artificial Intelligence, ECAI (2014,2016)

  • International Conference on Automated Planning and Scheduling, ICAPS (2015,2016,2017,2018,2020)

Reviewer

  • Journal of Artificial Intelligence Research, JAIR

  • Reviewer Artificial Intelligence, Elsevier AIJ

Teaching

  • Pacman Capture the flag Inter-University Contest, run for Unimelb AI coure and Hall of Fame contest, 2016 - current

  • AI Planning for Autonomy (Lecturer), at M.Sc. AI specialization, The University of Melbourne, 2016 - current

  • Data Structures and Algorithms (Lecturer), at The University of Melbourne, 2016 - current

  • Software Agents (Lecturer), at M.Sc. Software, The University of Melbourne, 2013, 2014, 2015

  • Autonomous Systems, at M.Sc. Intelligent Interactive Systems, University Pompeu Fabra, 2012

  • Advanced course on AI: workshop on RoboSoccer simulator, at Polytechnic School, University Pompeu Fabra, 2009, 2010, 2011

  • Artificial Intelligence course, at Polytechnic School, University Pompeu Fabra, 2010, 2011

  • Introduction to Data Structures and Algorithms course, at Polytechnic School, University Pompeu Fabra, 2008

  • Programming course, at Polytechnic School, University Pompeu Fabra, 2008, 2009, 2010, 2011

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