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 Planning & Scheduling


How you can use goal setting to get - and stay - in shape

Los Angeles Times

Some people finish a marathon, or climb Mt. Whitney, or get down to a certain weight, and that's it. They view that particular challenge as a sort of bucket-list accomplishment, and when they cross that finish line, they all but cross out fitness as a priority in their lives. They stop doing the things that helped them attain their goal and revert to poor habits. Soon enough, they're out of shape again (or have gained back all the weight).


Google Fit gets a colorful redesign and improved goal setting

Engadget

On the app's home page (above), Google has replaced the single activity dial graph with individual cards and dials for each goal, showing what you've done and how days you have left to meet it. Scrolling down will reveal a chart of your weight, recent workouts (complete with a map), and more (below). Hitting the floating action " " button lets you set new goals, log your weight, add an activity and more. As for the new goals, you can now get a lot more specific than before. It has more activities and more specific metrics, like steps, duration or times per week, day or month.


Combining the Delete Relaxation with Critical-Path Heuristics: A Direct Characterization

Journal of Artificial Intelligence Research

Recent work has shown how to improve delete relaxation heuristics by computing relaxed plans, i.e., the hFF heuristic, in a compiled planning task PiC which represents a given set C of fact conjunctions explicitly. While this compilation view of such partial delete relaxation is simple and elegant, its meaning with respect to the original planning task is opaque, and the size of PiC grows exponentially in |C|. We herein provide a direct characterization, without compilation, making explicit how the approach arises from a combination of the delete-relaxation with critical-path heuristics. Designing equations characterizing a novel view on h+ on the one hand, and a generalized version hC of hm on the other hand, we show that h+(PiC) can be characterized in terms of a combined hcplus equation. This naturally generalizes the standard delete-relaxation framework: understanding that framework as a relaxation over singleton facts as atomic subgoals, one can refine the relaxation by using the conjunctions C as atomic subgoals instead. Thanks to this explicit view, we identify the precise source of complexity in hFF(PiC), namely maximization of sets of supported atomic subgoals during relaxed plan extraction, which is easy for singleton-fact subgoals but is NP-complete in the general case. Approximating that problem greedily, we obtain a polynomial-time hCFF version of hFF(PiC), superseding the PiC compilation, and superseding the modified PiCce compilation which achieves the same complexity reduction but at an information loss. Experiments on IPC benchmarks show that these theoretical advantages can translate into empirical ones.


Obama's Education Department Has a Flawed Plan for Student Debt Forgiveness

U.S. News

If a change is needed, it is of a different kind. The process through which students may petition for loan forgiveness may need to be streamlined and made clearer. If it acts at all, the Department of Education should redefine the current process and better communicate its availability to students. The new initiative, even if that is not its intention, has the potential to go too far because those who feed off society's productive activities โ€“ because that's where the money is โ€“ will take it there. They will find ways to expand on language so vague its inevitably loose interpretation leaves public and private universities vulnerable to countless claims that are without merit.


The Robotics Race

#artificialintelligence

As robotic technologies continue to advance, along with related technologies such as speech and image recognition, memory and analytics, and virtual and augmented reality, better, faster, and cheaper robots will emerge. These machines โ€“ sophisticated, discerning, and increasingly autonomous โ€“ are certain to have an impact on business and society. But will they bring job displacement and danger or create new categories of employment and protect humankind? We talked to SAP's Kai Goerlich, along with Doug Stephen of the Institute for Human and Machine Cognition and Brett Kennedy from NASA's Jet Propulsion Laboratory, about the advances we can expect in robotics, robots' limitations, and their likely impact on the world. Kai Goerlich: Several trends will come together to drive the robotics market in the next 15 to 20 years.


Toward Efficient Task Assignment and Motion Planning for Large Scale Underwater Mission

arXiv.org Artificial Intelligence

- An Autonomous Underwater Vehicle (AUV) needs to possess a certain degree of autonomy for any particular underwater mission to fulfil the mission objectives successfully and ensure its safety in all stages of the mission in a large scale operating fi e ld . In this paper, a novel combinatorial conflict - free - task ass ignment strategy consisting of an interactive engagement of a local path planner and an adaptive global route planner, is introduced. The method takes advantage of the heuristic search potency of the Particle Swarm Optimization (PSO) algorithm to address t he discrete nature of routing - task assignment approach and the complexity of NP - hard path planning problem. The proposed hybrid method, is highly efficient as a consequence of its reactive guidance framework that guarantees successful completion of mission s particularly in cluttered environments. To examine the performance of the method in a context of mission productivity, mission time management and vehicle safety, a series of simulation studies are undertaken. The results of simulations declare that the proposed method is reliable and robust, particularly in dealing with uncertainties, and it can significantly enhance the level of a vehicle's autonomy by relying on its reactive nature and capability of providing fast feasible solutions.


Recursive Constraint Manifold Subsearch for Multirobot Path Planning with Cooperative Tasks

AAAI Conferences

The Cooperative Path Planning (CPP) problem seeks to determine a path for a group of robots which form temporary teams to perform tasks. The multi-scale effects of simultaneously coordinating many robots distributed across the workspace while also tightly coordinating the members of teams increases the difficulty of planning. Previous research produced the Constraint Manifold Subsearch (CMS) algorithm that can find minimal length paths to the CPP problem. However, CMS as currently formulated cannot handle more general cost functions, such as minimizing energy expenditure, and cannot handle task schedules that require multiple input teams to merge to form a set of multiple output teams. Furthermore, as CMS must couple planning for all interacting teams, it does not scale well to very large environments. In this paper, we rederive the CMS algorithm using a task graph to reason about inter-team dependencies, allowing the use of more general cost functions and task schedules. We then introduce the recursive CMS (rCMS) algorithm that exploits the reformulation to split the CPP into independent subproblems, significantly reducing computational complexity. Simulation studies show that rCMS can solve substantially larger problems than CMS.


Numeric Planning via Search Space Abstraction (Extended Abstract)

AAAI Conferences

Many real-world planning problems are best modeled as infinite search space problems, using numeric fluents. Unfortunately, most planners and planning heuristics do not directly support such fluents. We propose a search space abstraction technique that compiles a planning problem with numeric fluents into a finite state propositional planning problem. To account for the loss of precision resulting from the abstraction, we leverage a policy repair technique used for non-deterministic planning. We evaluate our approach on a set of benchmarks and compare it to state-of-the-art planners that deal with numeric fluents.


Path Planning in Dynamic Environments with Adaptive Dimensionality

AAAI Conferences

Path planning in the presence of dynamic obstacles is a challenging problem due to the added time dimension in search space. In approaches that ignore the time dimension and treat dynamic obstacles as static, frequent re-planning is unavoidable as the obstacles move, and their solutions are generally sub-optimal and can be incomplete. To achieve both optimality and completeness, it is necessary to consider the time dimension during planning. The notion of adaptive dimensionality has been successfully used in high-dimensional motion planning such as manipulation of robot arms, but has not been used in the context of path planning in dynamic environments. In this paper, we apply the idea of adaptive dimensionality to speed up path planning in dynamic environments for a robot with no assumptions on its dynamic model. Specifically, our approach considers the time dimension only in those regions of the environment where a potential collision may occur, and plans in a low-dimensional state-space elsewhere. We show that our approach is complete and is guaranteed to find a solution, if one exists, within a cost sub-optimality bound. We experimentally validate our method on the problem of 3D vehicle navigation (x, y, heading) in dynamic environments. Our results show that the presented approach achieves substantial speedups in planning time over 4D heuristic-based A*, especially when the resulting plan deviates significantly from the one suggested by the heuristic.


A Hybrid Quantum-Classical Approach to Solving Scheduling Problems

AAAI Conferences

An effective approach to solving complex problems is to decompose them and integrate dedicated solvers for those subproblems. We introduce a hybrid decomposition that incorporates: (1) a quantum annealer that samples from the configuration space of a relaxed problem to obtain strong candidate solutions, and (2) a classical processor that maintains a global search tree and enforces constraints on the relaxed components of the problem. Our framework is the first to use quantum annealing as part of a complete search. We consider variants of our approach with differing amounts of guidance from the quantum annealer. We empirically test our algorithm and compare the variants on problems from three scheduling domains: graph-coloring-type scheduling, simplified Mars Lander task scheduling, and airport runway scheduling. While we were only able to test on problems of small sizes, due to the limitation of currently available quantum annealing hardware, the empirical results show that results obtained from the quantum annealer can be used for more effective search node pruning and to improve node selection heuristics when compared to a standard classical approach.