Planning & Scheduling
Discrete Word Embedding for Logical Natural Language Understanding
In this paper, we propose an unsupervised neural model for learning a discrete embedding of words. While being discrete, our embedding supports vector arithmetic operations similar to continuous embeddings by interpreting each word as a set of propositional statements describing a rule. The formulation of our vector arithmetic closely reflects the logical structure originating from the symbolic sequential decision making formalism (classical/STRIPS planning). Contrary to the conventional wisdom that discrete representation cannot perform well due to the lack of ability to capture the uncertainty, our representation is competitive against the continuous representations in several downstream tasks. We demonstrate that our embedding is directly compatible with the symbolic, classical planning solvers by performing a "paraphrasing" task. Due to the discrete/logical decision making in classical algorithms with deterministic (non-probabilistic) completeness, and also because it does not require additional training on the paraphrasing dataset, our system can negatively answer a paraphrasing query (inexistence of solutions), and can answer that only some approximate solutions exist -- A feature that is missing in the recent, huge, purely neural language models such as GPT-3.
Federated Learning for Cellular-connected UAVs: Radio Mapping and Path Planning
Khamidehi, Behzad, Sousa, Elvino S.
To prolong the lifetime of the unmanned aerial vehicles (UAVs), the UAVs need to fulfill their missions in the shortest possible time. In addition to this requirement, in many applications, the UAVs require a reliable internet connection during their flights. In this paper, we minimize the travel time of the UAVs, ensuring that a probabilistic connectivity constraint is satisfied. To solve this problem, we need a global model of the outage probability in the environment. Since the UAVs have different missions and fly over different areas, their collected data carry local information on the network's connectivity. As a result, the UAVs can not rely on their own experiences to build the global model. This issue affects the path planning of the UAVs. To address this concern, we utilize a two-step approach. In the first step, by using Federated Learning (FL), the UAVs collaboratively build a global model of the outage probability in the environment. In the second step, by using the global model obtained in the first step and rapidly-exploring random trees (RRTs), we propose an algorithm to optimize UAVs' paths. Simulation results show the effectiveness of this two-step approach for UAV networks.
DeComplex: Task planning from complex natural instructions by a collocating robot
Pramanick, Pradip, Barua, Hrishav Bakul, Sarkar, Chayan
As the number of robots in our daily surroundings like home, office, restaurants, factory floors, etc. are increasing rapidly, the development of natural human-robot interaction mechanism becomes more vital as it dictates the usability and acceptability of the robots. One of the valued features of such a cohabitant robot is that it performs tasks that are instructed in natural language. However, it is not trivial to execute the human intended tasks as natural language expressions can have large linguistic variations. Existing works assume either single task instruction is given to the robot at a time or there are multiple independent tasks in an instruction. However, complex task instructions composed of multiple inter-dependent tasks are not handled efficiently in the literature. There can be ordering dependency among the tasks, i.e., the tasks have to be executed in a certain order or there can be execution dependency, i.e., input parameter or execution of a task depends on the outcome of another task. Understanding such dependencies in a complex instruction is not trivial if an unconstrained natural language is allowed. In this work, we propose a method to find the intended order of execution of multiple inter-dependent tasks given in natural language instruction. Based on our experiment, we show that our system is very accurate in generating a viable execution plan from a complex instruction.
Perfect Reconstruction of Sparse Signals via Greedy Monte-Carlo Search
Hayashi, Kao, Obuchi, Tomoyuki, Kabashima, Yoshiyuki
We propose a Monte-Carlo-based method for reconstructing sparse signals in the formulation of sparse linear regression in a high-dimensional setting. The basic idea of this algorithm is to explicitly select variables or covariates to represent a given data vector or responses and accept randomly generated updates of that selection if and only if the energy or cost function decreases. This algorithm is called the greedy Monte-Carlo (GMC) search algorithm. Its performance is examined via numerical experiments, which suggests that in the noiseless case, GMC can achieve perfect reconstruction in undersampling situations of a reasonable level: it can outperform the $\ell_1$ relaxation but does not reach the algorithmic limit of MC-based methods theoretically clarified by an earlier analysis. Additionally, an experiment on a real-world dataset supports the practicality of GMC.
Reimagining City Configuration: Automated Urban Planning via Adversarial Learning
Wang, Dongjie, Fu, Yanjie, Wang, Pengyang, Huang, Bo, Lu, Chang-Tien
Urban planning refers to the efforts of designing land-use configurations. Effective urban planning can help to mitigate the operational and social vulnerability of a urban system, such as high tax, crimes, traffic congestion and accidents, pollution, depression, and anxiety. Due to the high complexity of urban systems, such tasks are mostly completed by professional planners. But, human planners take longer time. The recent advance of deep learning motivates us to ask: can machines learn at a human capability to automatically and quickly calculate land-use configuration, so human planners can finally adjust machine-generated plans for specific needs? To this end, we formulate the automated urban planning problem into a task of learning to configure land-uses, given the surrounding spatial contexts. To set up the task, we define a land-use configuration as a longitude-latitude-channel tensor, where each channel is a category of POIs and the value of an entry is the number of POIs. The objective is then to propose an adversarial learning framework that can automatically generate such tensor for an unplanned area. In particular, we first characterize the contexts of surrounding areas of an unplanned area by learning representations from spatial graphs using geographic and human mobility data. Second, we combine each unplanned area and its surrounding context representation as a tuple, and categorize all the tuples into positive (well-planned areas) and negative samples (poorly-planned areas). Third, we develop an adversarial land-use configuration approach, where the surrounding context representation is fed into a generator to generate a land-use configuration, and a discriminator learns to distinguish among positive and negative samples.
Learning excursion sets of vector-valued Gaussian random fields for autonomous ocean sampling
Fossum, Trygve Olav, Travelletti, Cรฉdric, Eidsvik, Jo, Ginsbourger, David, Rajan, Kanna
Improving and optimizing oceanographic sampling is a crucial task for marine science and maritime resource management. Faced with limited resources in understanding processes in the water-column, the combination of statistics and autonomous systems provide new opportunities for experimental design. In this work we develop efficient spatial sampling methods for characterizing regions defined by simultaneous exceedances above prescribed thresholds of several responses, with an application focus on mapping coastal ocean phenomena based on temperature and salinity measurements. Specifically, we define a design criterion based on uncertainty in the excursions of vector-valued Gaussian random fields, and derive tractable expressions for the expected integrated Bernoulli variance reduction in such a framework. We demonstrate how this criterion can be used to prioritize sampling efforts at locations that are ambiguous, making exploration more effective. We use simulations to study and compare properties of the considered approaches, followed by results from field deployments with an autonomous underwater vehicle as part of a study mapping the boundary of a river plume. The results demonstrate the potential of combining statistical methods and robotic platforms to effectively inform and execute data-driven environmental sampling.
A Maximum Independent Set Method for Scheduling Earth Observing Satellite Constellations
Eddy, Duncan, Kochenderfer, Mykel J.
Operating Earth observing satellites requires efficient planning methods that coordinate activities of multiple spacecraft. The satellite task planning problem entails selecting actions that best satisfy mission objectives for autonomous execution. Task scheduling is often performed by human operators assisted by heuristic or rule-based planning tools. This approach does not efficiently scale to multiple assets as heuristics frequently fail to properly coordinate actions of multiple vehicles over long horizons. Additionally, the problem becomes more difficult to solve for large constellations as the complexity of the problem scales exponentially in the number of requested observations and linearly in the number of spacecraft. It is expected that new commercial optical and radar imaging constellations will require automated planning methods to meet stated responsiveness and throughput objectives. This paper introduces a new approach for solving the satellite scheduling problem by generating an infeasibility-based graph representation of the problem and finding a maximal independent set of vertices for the graph. The approach is tested on a scenarios of up to 10,000 requested imaging locations for the Skysat constellation of optical satellites as well as simulated constellations of up to 24 satellites. Performance is compared with contemporary graph-traversal and mixed-integer linear programming approaches. Empirical results demonstrate improvements in both the solution time along with the number of scheduled collections beyond baseline methods. For large problems, the maximum independent set approach is able find a feasible schedule with 8% more collections in 75% less time.
Planimation
Chen, Gang, Ding, Yi, Edwards, Hugo, Chau, Chong Hin, Hou, Sai, Johnson, Grace, Syed, Mohammed Sharukh, Tang, Haoyuan, Wu, Yue, Yan, Ye, Tidhar, Gil, Lipovetzky, Nir
The declarative visual animation language decouples The adoption of a standard declarative specification of planning the visualisation engine in the same way PDDL decouples tasks through PDDL (McDermott et al. 1998), fostered models from solvers. PDDL modelers can extend their problems by International Planning Competitions (McDermott 2000), with a single animation profile and visualize the plans has boosted the development of solvers by the research community.
Metaheuristics for the operating theater planning and scheduling: A systematic review
Moosavi, Amirhossein, Ozturk, Onur
Healthcare expenses represent a large share of most developing countries' GDP. Operational theatres make up the majority of these costs in hospitals. There are found a vast number of papers studying the problem of operating theater planning and scheduling. Different variants of this problem are generally recognized to be NPcomplete; thus, several solution approaches have been utilized in the literature to confront with these complicated problems. The lack of a thorough review of the main characteristics of solution approaches is tangible in the literature (reviewing them separately and with regards to the characteristics of studied problems), which can provide pragmatic guidelines for practitioners and future research projects. This paper aims to address this issue. Since different types of solution approaches usually have different characteristics, this paper focuses only on metaheuristic algorithms. Through both automatic and manual search methods, we have selected and reviewed 28 papers with respect to their main problem and solution approach features. Finally, some directions are introduced for future research.
Learning Neural-Symbolic Descriptive Planning Models via Cube-Space Priors: The Voyage Home (to STRIPS)
Asai, Masataro, Muise, Christian
E.g., its search space was shown to be compatible with symbolic Goal Recognition [Amado et al., 2018]. We achieved a new milestone in the difficult task One major drawback of the previous work was that it used of enabling agents to learn about their environment a non-descriptive, black-box neural model as the successor autonomously. Our neuro-symbolic architecture is generator. Not only that such a black-box model is incompatible trained end-to-end to produce a succinct and effective with the existing heuristic search techniques, but also, discrete state transition model from images since a neural network is able to model a very complex function, alone. Our target representation (the Planning Domain its direct translation into a compact logical formula via Definition Language) is already in a form that a rule-based transfer learning method turned out futile [Asai, off-the-shelf solvers can consume, and opens the 2019a]: The model complexity causes an exponentially large door to the rich array of modern heuristic search grounded action model that cannot be processed by the modern capabilities. We demonstrate how the sophisticated classical planners. Thus, obtaining the descriptive action innate prior we place on the learning process significantly models from the raw observations with minimal human interference reduces the complexity of the learned representation, is the next key milestone for expanding the scope of and reveals a connection to the graphtheoretic applying Automated Planning to the raw unstructured inputs.