Booklet & Papers

@proceedings{IPC2020Booklet,
  title     = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  editor    = {Gregor Behnke and Daniel H{\"o}ller and Pascal Bercher},
  url_booklet = {https://ipc2020.hierarchical-task.net/publications/IPC2020Booklet.pdf},
  abstract  = {<p>Since its first edition in 1998, the International Planning Competition (IPC) has been an integral event of the planning community. For more than 20 years, it established unified input languages for planners, enabled an objective comparison between them based on an accessible benchmark set. The IPC drove the development of planners and fostered research. Thus, the IPC enabled planning researchers to compare their own work against the work of others -- not only within the competition, but also outside of it. Due to the IPC almost all contemporary planners understand (some form of) PDDL, which allows for using IPC benchmarks across a multitude of planners.</p>

<p>The first two IPCs had -- in addition to the regular track -- a track on hand-tailored planners in which the planners could be provided with additional information or select their algorithms based on the input domain. Among these planners, some used Hierarchical Planning -- most notably SHOP. Following the second IPC in 2000 the hand-tailored track was discontinued. Hierarchical planning was thereafter not part of the IPC any more. Research in the field however continued.</p>

<p>The International Planning Competition 2020 features for the first time a track dedicated to hierarchical planning. In contrast to the previous track on hand-tailored planners we don't want to evaluate how good planners can become given any possible additional knowledge, but ask how well planners can exploit a given hierarchical refinement structure. We therefore faced several unique challenges. We had to establish a common input language for all planners such that all of them operate on the very same model. We also had to specify a plan-output format and provide a verifier, since we had to ensure that the found plans satisfy the decompositional structure of the given task hierarchy. Further, we had to gather a comprehensive set of benchmark domains, since no such set existed before. We hope that this first competition for Hierarchical Task Network planners will foster future research into hierarchical planning and provide a common basis for many researchers -- by establishing a unified input language, a common benchmark set, and an evaluation of the state of the art in HTN planning. We hope that many future editions of this competition will follow.</p>

Gregor, Daniel, and Pascal<br/>
Organizers of the IPC 2020,<br/>
May 2021}
}

Since its first edition in 1998, the International Planning Competition (IPC) has been an integral event of the planning community. For more than 20 years, it established unified input languages for planners, enabled an objective comparison between them based on an accessible benchmark set. The IPC drove the development of planners and fostered research. Thus, the IPC enabled planning researchers to compare their own work against the work of others – not only within the competition, but also outside of it. Due to the IPC almost all contemporary planners understand (some form of) PDDL, which allows for using IPC benchmarks across a multitude of planners.

The first two IPCs had – in addition to the regular track – a track on hand-tailored planners in which the planners could be provided with additional information or select their algorithms based on the input domain. Among these planners, some used Hierarchical Planning – most notably SHOP. Following the second IPC in 2000 the hand-tailored track was discontinued. Hierarchical planning was thereafter not part of the IPC any more. Research in the field however continued.

The International Planning Competition 2020 features for the first time a track dedicated to hierarchical planning. In contrast to the previous track on hand-tailored planners we don't want to evaluate how good planners can become given any possible additional knowledge, but ask how well planners can exploit a given hierarchical refinement structure. We therefore faced several unique challenges. We had to establish a common input language for all planners such that all of them operate on the very same model. We also had to specify a plan-output format and provide a verifier, since we had to ensure that the found plans satisfy the decompositional structure of the given task hierarchy. Further, we had to gather a comprehensive set of benchmark domains, since no such set existed before. We hope that this first competition for Hierarchical Task Network planners will foster future research into hierarchical planning and provide a common basis for many researchers – by establishing a unified input language, a common benchmark set, and an evaluation of the state of the art in HTN planning. We hope that many future editions of this competition will follow.

Gregor, Daniel, and Pascal
Organizers of the IPC 2020,
May 2021

@inproceedings{Olivares2021SIADEX,
  title     = {Addressing {HTN} Planning with Blind Depth First Search},
  author    = {Fernandez-Olivares, Juan and Vellido, Ignacio and Castillo, Luis},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {1--4},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p10-p13.pdf},
  abstract  = {This paper briefly describes SIADEX, the HTN planner winner of the Partial Order track in the 2020 International Planning Competition. We also show a discussion of the results regarding run time and memory usage for the different problems configured in the competition}
}

This paper briefly describes SIADEX, the HTN planner winner of the Partial Order track in the 2020 International Planning Competition. We also show a discussion of the results regarding run time and memory usage for the different problems configured in the competition

@inproceedings{Magnaguagno2021HyperTensioN,
  title     = {{HyperTensioN}: {A} three-stage compiler for planning},
  author    = {Maur\'{i}cio Cec\'{i}lio Magnaguagno and Felipe Meneguzzi and Lavindra {de} Silva},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {5--8},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p14-p17.pdf},
  abstract  = {Hierarchical Task Networks (HTN) planners generate plans using a decomposition process with extra domain knowledge to guide search towards a planning task. While many HTN domain descriptions are made by experts, they may repeatedly describe the same preconditions, or methods that are rarely used or possible to be decomposed. By leveraging a three-stage compiler design we can easily support more language descriptions and preprocessing optimizations that when chained can greatly improve runtime efficiency in such domains. In this paper we present the HyperTensioN HTN planner, as it was submitted to the HTN IPC 2020.}
}

Hierarchical Task Networks (HTN) planners generate plans using a decomposition process with extra domain knowledge to guide search towards a planning task. While many HTN domain descriptions are made by experts, they may repeatedly describe the same preconditions, or methods that are rarely used or possible to be decomposed. By leveraging a three-stage compiler design we can easily support more language descriptions and preprocessing optimizations that when chained can greatly improve runtime efficiency in such domains. In this paper we present the HyperTensioN HTN planner, as it was submitted to the HTN IPC 2020.

@inproceedings{Schreiber2020LiloTane,
  title     = {Lifted Logic for Task Networks: {TOHTN} Planner Lilotane in the {IPC} 2020},
  author    = {Schreiber, Dominik},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {9--12},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p18-p21.pdf},
  abstract  = {We present our contribution to the International Planning Competition (IPC) 2020. Our planner Lilotane builds upon ideas established by Tree-REX and encodes a Totally Ordered Hierarchical Task Network (TOHTN) planning problem into incremental formulae of propositional logic (SAT). Lilotane, however, instantiates reductions and actions lazily and minimalistically without the need for full grounding, hence accelerating the planning process significantly. We discuss the results of the IPC and conclude that Lilotane, scoring second in the Total Order track, is an overall competitive system, what demonstrates the viability of our approach and its significance for future research.}
}

We present our contribution to the International Planning Competition (IPC) 2020. Our planner Lilotane builds upon ideas established by Tree-REX and encodes a Totally Ordered Hierarchical Task Network (TOHTN) planning problem into incremental formulae of propositional logic (SAT). Lilotane, however, instantiates reductions and actions lazily and minimalistically without the need for full grounding, hence accelerating the planning process significantly. We discuss the results of the IPC and conclude that Lilotane, scoring second in the Total Order track, is an overall competitive system, what demonstrates the viability of our approach and its significance for future research.

@inproceedings{Lesire2021pyHiPOP,
  title     = {{pyHiPOP} -- {H}ierarchical Partial-Order Planner},
  author    = {Lesire, Charles and Albore, Alexandre},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {13--16},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p22-p25.pdf},
  abstract  = {PYHIPOP is a hierarchical partial-order planner, aimed at solving Hierarchical Task Network (HTN) planning problems. The current planner version is a re-coding of a version originally developed by Patrick Bechon (Bechon et al. 2014). In Bechon’s original work, HIPOP solved HTN problems with Task Insertion (TI-HTN), meaning that inserting new tasks in addition to the pure HTN decomposition was allowed during the search. Bechon proposed some heuristics for solving such problems using a hybrid algorithm: a POP (Partial Order Planning) algorithm with hierarchical task decomposition. HIPOP has also been extended to manage plan repair (Bechon et al. 2015), and multi-robot mission planning repair with communications losses (Bechon, Lesire, and Barbier 2020). PYHIPOP differs from the original HIPOP in:<br/>
• PYHIPOP is coded in pure Python3; this choice has been made to ease the integration with other tools for plan repair or interactive planning;<br/>
• PYHIPOP currently manages HTN problems only – no Task Insertion is allowed;<br/>
• PYHIPOP’s preprocessing and grounding steps have been improved to use recent works from the state of the art;<br/>
• PYHIPOP’s heuristics have been adapted, as its original heuristics worked well for TI-HTN, but not so well for pure HTN problems.}
}

PYHIPOP is a hierarchical partial-order planner, aimed at solving Hierarchical Task Network (HTN) planning problems. The current planner version is a re-coding of a version originally developed by Patrick Bechon (Bechon et al. 2014). In Bechon’s original work, HIPOP solved HTN problems with Task Insertion (TI-HTN), meaning that inserting new tasks in addition to the pure HTN decomposition was allowed during the search. Bechon proposed some heuristics for solving such problems using a hybrid algorithm: a POP (Partial Order Planning) algorithm with hierarchical task decomposition. HIPOP has also been extended to manage plan repair (Bechon et al. 2015), and multi-robot mission planning repair with communications losses (Bechon, Lesire, and Barbier 2020). PYHIPOP differs from the original HIPOP in:
• PYHIPOP is coded in pure Python3; this choice has been made to ease the integration with other tools for plan repair or interactive planning;
• PYHIPOP currently manages HTN problems only – no Task Insertion is allowed;
• PYHIPOP’s preprocessing and grounding steps have been improved to use recent works from the state of the art;
• PYHIPOP’s heuristics have been adapted, as its original heuristics worked well for TI-HTN, but not so well for pure HTN problems.

@inproceedings{Pellier2021PDDL4J,
  title     = {Totally and Partially Ordered Hierarchical Planners in {PDDL4J} Library},
  author    = {Pellier, Damien and Fiorino, Humbert},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {17--18},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p26-p27.pdf},
  abstract  = {In this paper, we outline the implementation of the TFD (Totally Ordered Fast Downward) and the PFD (Partially ordered Fast Downward) hierarchical planners that participated in the first HTN IPC competition in 2020. These two planners are based on forward-chaining task decomposition coupled with a compact grounding of actions, methods, tasks and HTN problems.}
}

In this paper, we outline the implementation of the TFD (Totally Ordered Fast Downward) and the PFD (Partially ordered Fast Downward) hierarchical planners that participated in the first HTN IPC competition in 2020. These two planners are based on forward-chaining task decomposition coupled with a compact grounding of actions, methods, tasks and HTN problems.

@inproceedings{Behnke2021Assembly,
  title     = {Assembly{H}ierarchical -- {C}onnecting Devices through Cables},
  author    = {Behnke, Gregor},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {19--20},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p28-p29.pdf},
  abstract  = {We report on the AssemblyHierarchical domain, which encodes the task of connecting devices through a set of availables cables.}
}

We report on the AssemblyHierarchical domain, which encodes the task of connecting devices through a set of availables cables.

@inproceedings{Pellier2021Domains,
  title     = {From Classical to Hierarchical: {B}enchmarks for the {HTN} Track of the International Planning Competition},
  author    = {Pellier, Damien and Fiorino, Humbert},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {21--23},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p30-p32.pdf},
  abstract  = {In this short paper, we outline nine classical benchmarks submitted to the first hierarchical planning track of the International Planning competition in 2020. All of these benchmarks are based on the HDDL language (H\"oller et al. 2020). The choice of the benchmarks was based on a questionnaire sent to the HTN community (Behnke et al. 2019). They are the following: Barman, Childsnack, Rover, Satellite, Blocksworld, Depots, Gripper, and Hiking. In the rest of the paper we give a short description of these benchmarks. All are totally ordered. A first hierarchical version of the domains Barman, Childsnack, Rover, Satellite, Blocksworld were proposed by (Ramoul et al. 2017; Schreiber et al. 2019). All the domains presented here are available online as part of the PDDL4J library (Pellier and Fiorino 2018). The writing of the domains has been a collective work. We would like to thank all the other contributors, D. Ramoul, D. Schreiber and A. Lequen.}
}

In this short paper, we outline nine classical benchmarks submitted to the first hierarchical planning track of the International Planning competition in 2020. All of these benchmarks are based on the HDDL language (Höller et al. 2020). The choice of the benchmarks was based on a questionnaire sent to the HTN community (Behnke et al. 2019). They are the following: Barman, Childsnack, Rover, Satellite, Blocksworld, Depots, Gripper, and Hiking. In the rest of the paper we give a short description of these benchmarks. All are totally ordered. A first hierarchical version of the domains Barman, Childsnack, Rover, Satellite, Blocksworld were proposed by (Ramoul et al. 2017; Schreiber et al. 2019). All the domains presented here are available online as part of the PDDL4J library (Pellier and Fiorino 2018). The writing of the domains has been a collective work. We would like to thank all the other contributors, D. Ramoul, D. Schreiber and A. Lequen.

@inproceedings{Hoeller2021PCP,
  title     = {From {PCP} to {HTN} Planning Through {CFG}s},
  author    = {H\"oller, Daniel and Lin, Songtuan and Erol, Kutluhan and Bercher, Pascal},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {24--25},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p33-p34.pdf},
  abstract  = {The International Planning Competition in 2020 was the first one for a long time to host tracks on HTN planning. The used benchmark set included a domain describing the undecidable Post Correspondence Problem (PCP). In this paper we describe the two-step process applied to generate HTN problems based on PCP instances. It translates the PCP into a grammar intersection problem of two context-free languages, which is then encoded into an HTN problem.}
}

The International Planning Competition in 2020 was the first one for a long time to host tracks on HTN planning. The used benchmark set included a domain describing the undecidable Post Correspondence Problem (PCP). In this paper we describe the two-step process applied to generate HTN problems based on PCP instances. It translates the PCP into a grammar intersection problem of two context-free languages, which is then encoded into an HTN problem.

@inproceedings{Lotinac2021Learned,
  title     = {Hierarchical Task Networks Generated Using Invariant Graphs for {IPC}2020},
  author    = {Lotinac, Damir and Kominis, Filippos and Jonsson, Anders},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {26--30},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p35-p39.pdf},
  abstract  = {The International Planning Competition in 2020 was the first one for a long time to host tracks on HTN planning. The used benchmark set included a domain describing the undecidable Post Correspondence Problem (PCP). In this paper we describe the two-step process applied to generate HTN problems based on PCP instances. It translates the PCP into a grammar intersection problem of two context-free languages, which is then encoded into an HTN problem.}
}

The International Planning Competition in 2020 was the first one for a long time to host tracks on HTN planning. The used benchmark set included a domain describing the undecidable Post Correspondence Problem (PCP). In this paper we describe the two-step process applied to generate HTN problems based on PCP instances. It translates the PCP into a grammar intersection problem of two context-free languages, which is then encoded into an HTN problem.

@inproceedings{Alford2021Blocksworld,
  title     = {{HTN} {IPC}-2020 Domains: {B}locksworld-{HPDDL} and Multiarm-Blocksworld},
  author    = {Alford, Ron},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {31--31},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p40-p40.pdf},
  abstract  = {The Blocksworld-HDDL problems from the 2020 HTN International Planning Competition were adapted from the HTN translation papers by Alford et al.. The domain enforces a strategy of only picking up blocks to move, and placing them either in their final location or on the table. The Multiarm-Blocksworld domain extends the domain by allowing for multiple independent arms.}
}

The Blocksworld-HDDL problems from the 2020 HTN International Planning Competition were adapted from the HTN translation papers by Alford et al.. The domain enforces a strategy of only picking up blocks to move, and placing them either in their final location or on the table. The Multiarm-Blocksworld domain extends the domain by allowing for multiple independent arms.

@inproceedings{Alford2021Robot,
  title     = {{HTN} {IPC}-2020 Domain: {R}obot},
  author    = {Alford, Ron},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {32--32},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p41-p41.pdf},
  abstract  = {The Robot problems from the 2020 HTN International Planning Competition were adapted from the HTN translation papers by Alford et al.. The domain encodes an office delivery problem, and enforces a strategy of only picking up packages that are not in their goal location, and only placing packages in their final location. Package order and navigation are left up to the choices of the planner.}
}

The Robot problems from the 2020 HTN International Planning Competition were adapted from the HTN translation papers by Alford et al.. The domain encodes an office delivery problem, and enforces a strategy of only picking up packages that are not in their goal location, and only placing packages in their final location. Package order and navigation are left up to the choices of the planner.

@inproceedings{Alford2021Towers,
  title     = {{HTN} {IPC}-2020 Domain: {T}owers},
  author    = {Alford, Ron},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {33--33},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p42-p42.pdf},
  abstract  = {The Towers domain from the 2020 HTN International Planning Competition was adapted from the HTN translation papers by Alford et al.. The domain encodes a solution to the Towers of Hanoi problem, admitting a unique, optimal solution and having no branches in the search space}
}

The Towers domain from the 2020 HTN International Planning Competition was adapted from the HTN translation papers by Alford et al.. The domain encodes a solution to the Towers of Hanoi problem, admitting a unique, optimal solution and having no branches in the search space

@inproceedings{Georgievski2021Deployment,
  title     = {HTN Planning Domain for Deployment of Cloud Applications},
  author    = {Georgievski, Ilche},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {34--36},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p43-p45.pdf},
  abstract  = {Cloud providers are facing a complex problem in configuring software applications ready for deployment on their infrastructures. Hierarchical Task Network (HTN) planning can provide effective means to solve such deployment problems. We present an HTN planning domain that models deployment problems as found in realistic Cloud environments.}
}

Cloud providers are facing a complex problem in configuring software applications ready for deployment on their infrastructures. Hierarchical Task Network (HTN) planning can provide effective means to solve such deployment problems. We present an HTN planning domain that models deployment problems as found in realistic Cloud environments.

@inproceedings{Magnaguagno2021Snake,
  title     = {Snake Domain for {HTN} {IPC} 2020},
  author    = {Magnaguagno, Maur\'{i}cio Cec\'{i}lio},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {37--38},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p46-p47.pdf},
  abstract  = {This is a description of the Snake domain and problem generator submitted to the HTN IPC 2020 total order track. In the Snake domain the goal is to hunt mice spread over multiple locations, with one or more snakes that get longer as they strike each mouse}
}

This is a description of the Snake domain and problem generator submitted to the HTN IPC 2020 total order track. In the Snake domain the goal is to hunt mice spread over multiple locations, with one or more snakes that get longer as they strike each mouse

@inproceedings{Waters2021Barman,
  title     = {The Barman-{HTN} Domain for {IPC} 2020},
  author    = {Waters, Max and Padgham, Lin and Sardina, Sebastian},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {39--39},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p48-p48.pdf},
  abstract  = {The Barman-HTN domain is an HTN decomposition of the IPC Barman domain. It extends Barman with a task network that guides cocktail creation while retaining the primitive operators that made the original so challenging for the delete- relaxation heuristic.}
}

The Barman-HTN domain is an HTN decomposition of the IPC Barman domain. It extends Barman with a task network that guides cocktail creation while retaining the primitive operators that made the original so challenging for the delete- relaxation heuristic.

@inproceedings{Schattenberg2021Satellite,
  title     = {The Hierarchical Satellite Domain},
  author    = {Schattenberg, Bernd},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {40--42},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p49-p51.pdf},
  abstract  = {The Satellite domain is one of the classical benchmark domains in the canon of the International Planning Competition. This paper describes our hierarchical take on it.}
}

The Satellite domain is one of the classical benchmark domains in the canon of the International Planning Competition. This paper describes our hierarchical take on it.

@inproceedings{Schattenberg2021Woodworking,
  title     = {The Hierarchical Woodworking Domain},
  author    = {Schattenberg, Bernd and Bercher, Pascal},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {43--44},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p52-p53.pdf},
  abstract  = {The Woodworking domain is one of the classical benchmark domains in the canon of the International Planning Competition. This paper describes our hierarchical take on it.}
}

The Woodworking domain is one of the classical benchmark domains in the canon of the International Planning Competition. This paper describes our hierarchical take on it.

@inproceedings{Soennichsen2021Factory,
  title     = {The {HTN} Domain ``Factories''},
  author    = {S\"{o}nnichsen, Malte and Schreiber, Dominik},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {45--46},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p54-p55.pdf},
  abstract  = {In this paper we present the benchmark domain “Factories” for Hierarchical Task Network (HTN) planning written in the HDDL format (H\"oller et al. 2020). In this benchmark domain, the planning objective is to construct a factory by satisfying a dependency graph on certain resources while using trucks to deliver the needed resources from one place to another. As such, our domain is a crossover of traditional logistics and transport domains with a producer-consumer problem}
}

In this paper we present the benchmark domain “Factories” for Hierarchical Task Network (HTN) planning written in the HDDL format (Höller et al. 2020). In this benchmark domain, the planning objective is to construct a factory by satisfying a dependency graph on certain resources while using trucks to deliver the needed resources from one place to another. As such, our domain is a crossover of traditional logistics and transport domains with a producer-consumer problem

@inproceedings{Bercher2021SmartPhone,
  title     = {The Smartphone Domain},
  author    = {Bercher, Pascal and Biundo, Susanne and Schattenberg, Bernd},
  booktitle = {Proceedings of the 10th {I}nternational {P}lanning {C}ompetition: Planner and Domain Abstracts -- Hierarchical Task Network (HTN) Planning Track (IPC 2020)},
  year      = {2021},
  pages     = {47--47},
  url_paper = {https://ipc2020.hierarchical-task.net/publications/proceedings_p56-p56.pdf},
  abstract  = {This extended abstract is about the Smartphone domain, submitted as a benchmark domain to the IPC 2020.}
}

This extended abstract is about the Smartphone domain, submitted as a benchmark domain to the IPC 2020.

@Inproceedings{Behnke2019HTN-IPC,
   author          = {Gregor Behnke and Daniel H{\"o}ller and Pascal Bercher and Susanne Biundo and Damien Pellier and Humbert Fiorino and Ron Alford},
   title           = {Hierarchical Planning in the IPC},
   year            = {2019},
   booktitle       = {Proceedings of the Workshop on the International Planning Competition},
   abstract        = {Over the last years, the amount of research in hierarchical planning has increased, leading to significant improvements in the performance of planners. However, the research is diverging and planners are somewhat hard to compare against each other. This is mostly caused by the fact that there is no standard set of benchmark domains, nor even a common description language for hierarchical planning problems. As a consequence, the available planners support a widely varying set of features and (almost) none of them can solve (or even parse) any problem developed for another planner. With this paper, we propose to create a new track for the IPC in which hierarchical planners will compete. This competition will result in a standardised description language, broader support for core features of that language among planners, a set of benchmark problems, a means to fairly and objectively compare HTN planners, and for new challenges for planners.},
   url_Paper       = {https://bercher.net/publications/2019/Behnke2019HTN-IPC.pdf},
   url_Slides      = {https://bercher.net/publications/2019/Behnke2019HTN-IPCSlides.pdf}
}

Over the last years, the amount of research in hierarchical planning has increased, leading to significant improvements in the performance of planners. However, the research is diverging and planners are somewhat hard to compare against each other. This is mostly caused by the fact that there is no standard set of benchmark domains, nor even a common description language for hierarchical planning problems. As a consequence, the available planners support a widely varying set of features and (almost) none of them can solve (or even parse) any problem developed for another planner. With this paper, we propose to create a new track for the IPC in which hierarchical planners will compete. This competition will result in a standardised description language, broader support for core features of that language among planners, a set of benchmark problems, a means to fairly and objectively compare HTN planners, and for new challenges for planners.