{"title":"Timed Partial Order Inference Algorithm","authors":"Kandai Watanabe, Bardh Hoxha, D. Prokhorov, Georgios Fainekos, Morteza Lahijanian, Sriram Sankaranarayana, Tomoya Yamaguchi","doi":"10.48550/arXiv.2302.02501","DOIUrl":"https://doi.org/10.48550/arXiv.2302.02501","url":null,"abstract":"In this work, we propose the model of timed partial orders (TPOs) for specifying workflow schedules, especially for modeling manufacturing processes. TPOs integrate partial orders over events in a workflow, specifying ``happens-before'' relations, with timing constraints specified using guards and resets on clocks -- an idea borrowed from timed-automata specifications. TPOs naturally allow us to capture event ordering, along with a restricted but useful class of timing relationships. Next, we consider the problem of mining TPO schedules from workflow logs, which include events along with their time stamps. We demonstrate a relationship between formulating TPOs and the graph-coloring problem, and present an algorithm for learning TPOs with correctness guarantees.\u0000We demonstrate our approach on synthetic datasets, including two datasets inspired by real-life applications of aircraft turnaround and gameplay videos of the Overcooked computer game. Our TPO mining algorithm can infer TPOs involving hundreds of events from thousands of data-points within a few seconds. We show that the resulting TPOs provide useful insights into the dependencies and timing constraints for workflows.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123050282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Task Phasing: Automated Curriculum Learning from Demonstrations","authors":"Vaibhav Bajaj, Guni Sharon, P. Stone","doi":"10.48550/arXiv.2210.10999","DOIUrl":"https://doi.org/10.48550/arXiv.2210.10999","url":null,"abstract":"Applying reinforcement learning (RL) to sparse reward domains is notoriously challenging due to insufficient guiding signals. \u0000Common RL techniques for addressing such domains include (1) learning from demonstrations and (2) curriculum learning. While these two approaches have been studied in detail, they have rarely been considered together. This paper aims to do so by introducing a principled task-phasing approach that uses demonstrations to automatically generate a curriculum sequence. Using inverse RL from (suboptimal) demonstrations we define a simple initial task. Our task phasing approach then provides a framework to gradually increase the complexity of the task all the way to the target task, while retuning the RL agent in each phasing iteration. Two approaches for phasing are considered: (1) gradually increasing the proportion of time steps an RL agent is in control, and (2) phasing out a guiding informative reward function. We present conditions that guarantee the convergence of these approaches to an optimal policy. Experimental results on 3 sparse reward domains demonstrate that our task-phasing approaches outperform state-of-the-art approaches with respect to asymptotic performance.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116379624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Small Solution Hypothesis for MAPF on Strongly Connected Directed Graphs Is True","authors":"B. Nebel","doi":"10.1609/icaps.v33i1.27208","DOIUrl":"https://doi.org/10.1609/icaps.v33i1.27208","url":null,"abstract":"The determination of the computational complexity of multi-agent pathfinding on directed graphs (diMAPF) has been an open research problem for many years. While diMAPF has been shown to be polynomial for some special cases, only recently, it has been established that the problem is NP-hard in general. Further, it has been proved that diMAPF will be in NP if the short solution hypothesis for strongly connected directed graphs holds. In this paper, it is shown that this hypothesis is indeed true, even when one allows for synchronous rotations.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"22 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132791132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tom'as Delgado, Marco S'anchez Sorondo, V. Braberman, Sebastián Uchitel
{"title":"Exploration Policies for On-the-Fly Controller Synthesis: A Reinforcement Learning Approach","authors":"Tom'as Delgado, Marco S'anchez Sorondo, V. Braberman, Sebastián Uchitel","doi":"10.1609/icaps.v33i1.27238","DOIUrl":"https://doi.org/10.1609/icaps.v33i1.27238","url":null,"abstract":"Controller synthesis is in essence a case of model-based planning for non-deterministic environments in which plans (actually “strategies”) are meant to preserve system goals indefinitely. In the case of supervisory control environments are specified as the parallel composition of state machines and valid strategies are required to be “non-blocking” (i.e., always enabling the environment to reach certain marked states) in addition to safe (i.e., keep the system within a safe zone). Recently, On-the-fly Directed Controller Synthesis techniques were proposed to avoid the exploration of the entire -and exponentially large- environment space, at the cost of non-maximal permissiveness, to either find a strategy or conclude that there is none. The incremental exploration of the plant is currently guided by a domain-independent human-designed heuristic.\u0000In this work, we propose a new method for obtaining heuristics based on Reinforcement Learning (RL). The synthesis algorithm is thus framed as an RL task with an unbounded action space and a modified version of DQN is used. With a simple and general set of features that abstracts both states and actions, we show that it is possible to learn heuristics on small versions of a problem that generalize to the larger instances, effectively doing zero-shot policy transfer. Our agents learn from scratch in a highly partially observable RL task and outperform the existing heuristic overall, in instances unseen during training.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133064124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Uniform Machine Scheduling with Predictions","authors":"Tianming Zhao, Wei Li, Albert Y. Zomaya","doi":"10.1609/icaps.v32i1.19827","DOIUrl":"https://doi.org/10.1609/icaps.v32i1.19827","url":null,"abstract":"The revival in learning theory has provided us with improved capabilities for accurate predictions. This work contributes to an emerging research agenda of online scheduling with predictions by studying the makespan minimization in uniformly related machine non-clairvoyant scheduling with job size predictions. Our task is to design online algorithms that effectively use predictions and have performance guarantees with varying prediction quality. We first propose a simple algorithm-independent prediction error measurement to quantify prediction quality. To effectively use the predicted job sizes, we design an offline improved 2-relaxed decision procedure approximating the optimal schedule. With this decision procedure, we propose an online O(min{log eta, log m})-competitive algorithm that assumes a known prediction error. Finally, we extend this algorithm to construct a robust O(min{log eta, log m})-competitive algorithm that does not assume a known error. Both algorithms require only moderate predictions to improve the well-known Omega(log m) lower bound, showing the potential of using predictions in managing uncertainty.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126143893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiachen Zhang, Giovanni Lo Bianco, J. Christopher Beck
{"title":"Solving Job-Shop Scheduling Problems with QUBO-Based Specialized Hardware","authors":"Jiachen Zhang, Giovanni Lo Bianco, J. Christopher Beck","doi":"10.1609/icaps.v32i1.19826","DOIUrl":"https://doi.org/10.1609/icaps.v32i1.19826","url":null,"abstract":"The emergence of specialized hardware, such as quantum computers and Digital/CMOS annealers, and the slowing of performance growth of general-purpose hardware raises an important question for our community: how can the high-performance, specialized solvers be used for planning and scheduling problems? In this work, we focus on the job-shop scheduling problem (JSP) and Quadratic Unconstrained Binary Optimization (QUBO) models, the mathematical formulation shared by a number of novel hardware platforms. We study two direct QUBO models of JSP and propose a novel large neighborhood search (LNS) approach, that hybridizes a QUBO model with constraint programming (CP). Empirical results show that our LNS approach significantly outperforms classical CP-based LNS methods and a mixed integer programming model, while being competitive with CP for large problem instances. This work is the first approach that we are aware of that can solve non-trivial JSPs using QUBO hardware, albeit as part of a hybrid algorithm.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121918248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New Refinement Strategies for Cartesian Abstractions","authors":"David Speck, Jendrik Seipp","doi":"10.1609/icaps.v32i1.19819","DOIUrl":"https://doi.org/10.1609/icaps.v32i1.19819","url":null,"abstract":"Cartesian counterexample-guided abstraction refinement (CEGAR) yields strong heuristics for optimal classical planning. CEGAR repeatedly finds counterexamples, i.e., abstract plans that fail for the concrete task. Although there are usually many such abstract plans to choose from, the refinement strategy from previous work is to choose an arbitrary optimal one. In this work, we show that an informed refinement strategy is critical in theory and practice. We demonstrate that it is possible to execute all optimal abstract plans in the concrete task simultaneously, and present methods to minimize the time and number of refinement steps until we find a concrete solution. The resulting algorithm solves more tasks than the previous state of the art for Cartesian CEGAR, both during refinement and when used as a heuristic in an A* search.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121959372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rostislav Horcík, Á. Torralba, Pavel Rytír, L. Chrpa, S. Edelkamp
{"title":"Optimal Mixed Strategies for Cost-Adversarial Planning Games","authors":"Rostislav Horcík, Á. Torralba, Pavel Rytír, L. Chrpa, S. Edelkamp","doi":"10.1609/icaps.v32i1.19797","DOIUrl":"https://doi.org/10.1609/icaps.v32i1.19797","url":null,"abstract":"This paper shows that domain-independent tools from classical planning can be used to model and solve a broad class of game-theoretic problems we call Cost-Adversarial Planning Games (CAPGs). We define CAPGs as 2-player normal-form games specified by a planning task and a finite collection of cost functions. The first player (a planning agent) strives to solve a planning task optimally but has limited knowledge about its action costs. The second player (an adversary agent) controls the actual action costs. Even though CAPGs need not be zero-sum, every CAPG has an associated zero-sum game whose Nash equilibrium provides the optimal randomized strategy for the planning agent in the original CAPG. We show how to find the Nash equilibrium of the associated zero-sum game using a cost-optimal planner via the Double Oracle algorithm. To demonstrate the expressivity of CAPGs, we formalize a patrolling security game and several IPC domains as CAPGs.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121789495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Crossword Puzzle Resolution via Monte Carlo Tree Search","authors":"Lihan Chen, Jingping Liu, Sihang Jiang, Chao Wang, Jiaqing Liang, Yanghua Xiao, Shenmin Zhang, Rui Song","doi":"10.1609/icaps.v32i1.19783","DOIUrl":"https://doi.org/10.1609/icaps.v32i1.19783","url":null,"abstract":"Although the development of AI in games is remarkable, intelligent machines still lag behind humans in games that require the ability of language understanding. In this paper, we focus on the crossword puzzle resolution task. Solving crossword puzzles is a challenging task since it requires the ability to understand natural language and the ability to execute a search over possible answers to find an optimal set of solutions for the grid. Previous solutions are devoted to exploiting heuristic strategies in search to find solutions while having limited ability to explore the search space. We propose a solution for crossword puzzle resolution based on Monte Carlo tree search (MCTS). As far as we know, we are the first to model the crossword puzzle resolution problem as a Markov Decision Process and apply the MCTS to solve it. We construct a dataset for crossword puzzle resolution based on daily puzzles from New York Times with detailed specifications on both the puzzle and clue database selection. Our method can achieve an accuracy of 97% on the dataset.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130197434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Levinson, Samantha Niemoeller, S. Nag, V. Ravindra
{"title":"Planning Satellite Swarm Measurements for Earth Science Models: Comparing Constraint Processing and MILP Methods","authors":"R. Levinson, Samantha Niemoeller, S. Nag, V. Ravindra","doi":"10.1609/icaps.v32i1.19833","DOIUrl":"https://doi.org/10.1609/icaps.v32i1.19833","url":null,"abstract":"We compare two planner solutions for a challenging Earth science application to plan coordinated measurements (observations) for a constellation of satellites. This problem is combinatorially explosive, involving many degrees of freedom for planner choices. Each satellite carries two different sensors and is maneuverable to 61 pointing angle options. The sensors collect data to update the predictions made by a high-fidelity global soil moisture prediction model. Soil moisture is an important geophysical variable whose knowledge is used in applications such as crop health monitoring and predictions of floods, droughts, and fires.\u0000 The global soil-moisture model produces soil-moisture predictions with associated prediction errors over the globe represented by a grid of 1.67 million Ground Positions (GPs). The prediction error varies over space and time and can change drastically with events like rain/fire. The planner's goal is to select measurements which reduce prediction errors to improve future predictions. This is done by targeting high-quality observations at locations of high prediction-error. Observations can be made in multiple ways, such as by using one or more instruments or different pointing angles; the planner seeks to select the way with the least measurement-error (higher observation quality).\u0000 In this paper we compare two planning approaches to this problem: Dynamic Constraint Processing (DCP) and Mixed Integer Linear Programming (MILP). We match inputs and metrics for both DCP and MILP algorithms to enable a direct apples-to-apples comparison. DCP uses domain heuristics to find solutions within a reasonable time for our application but cannot be proven optimal, while the MILP produces provably optimal solutions. We demonstrate and discuss the trades between DCP flexibility and performance vs. MILP's promise of provable optimality.","PeriodicalId":239898,"journal":{"name":"International Conference on Automated Planning and Scheduling","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124545218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}