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Dynamic User Task Scheduling for Mobile Robots

AAAI Conferences

We present our efforts to deploy mobile robots in office environments, focusing in particular on the challenge of planning a schedule for a robot to accomplish user-requested actions. We concretely aim to make our CoBot mobile robots available to execute navigational tasks requested by users, such as telepresence, and picking up and delivering messages or objects at different locations. We contribute an efficient web-based approach in which users can request and schedule the execution of specific tasks. The scheduling problem is converted to a mixed integer programming problem. The robot executes the scheduled tasks using a synthetic speech and touch-screen interface to interact with users, while allowing users to follow the task execution online. Our robot uses a robust Kinect-based safe navigation algorithm, moves fully autonomously without the need to be chaperoned by anyone, and is robust to the presence of moving humans, as well as non-trivial obstacles, such as legged chairs and tables. Our robots have already performed 15km of autonomous service tasks.


Visual Search and Multirobot Collaboration Based on Hierarchical Planning

AAAI Conferences

Mobile robots are increasingly being used in the real-world due to the availability of high-fidelity sensors and sophisticated information processing algorithms. A key challenge to the widespread deployment of robots is the ability to accurately sense the environment and collaborate towards a common objective. Probabilistic sequential decision-making methods can be used to address this challenge because they encapsulate the partial observability and non-determinism of robot domains. However, such formulations soon become intractable for domains with complex state spaces that require real-time operation. Our prior work enabled a mobile robot to use hierarchical partially observable Markov decision processes (POMDPs) to automatically tailor visual sensing and information processing to the task at hand. This paper introduces adaptive observation functions and policy re-weighting in a three-layered POMDP hierarchy to enable reliable and efficient visual processing in dynamic domains. In addition, each robot merges its beliefs with those communicated by teammates, to enable a team of robots to collaborate robustly. All algorithms are evaluated in simulated domains and on physical robots tasked with locating target objects in indoor environments.


Task Behavior and Interaction Planning for a Mobile Service Robot that Occasionally Requires Help

AAAI Conferences

In our work, a robot can proactively ask for help when necessary, based on its awareness of its sensing and actuation limitations. Approaches in which humans provide help to robots do not necessarily reason about the human availability and accuracy. Instead, we model the availability of humans in the robot's environment and present a planning approach that uses such model to generate the robot navigational plans. In particular, we contribute two separate planners that allow a robot to distinguish actions that it cannot complete autonomously from ones that it can. In the first planner, the robot plans autonomous actions when possible and requests help to complete actions that it could not otherwise complete. Then for actions that it can perform autonomously, we use a POMDP policy that incorporates the human availability model to plan actions that reduce uncertainty or that increase the likelihood of the robot finding an available human to help it reduce its uncertainty. We have shown in prior work that asking people in the environment for help during tasks can reduce task completion time and increase the robot's ability to perform tasks.


A Planning Approach to Active Visual Search in Large Environments

AAAI Conferences

In this paper we present a principled planner based approach to the active visual object search problem in unknown environments. We make use of a hierarchical planner that combines the strength of decision theory and heuristics. Furthermore, our object search approach leverages on the conceptual spatial knowledge in the form of object co-occurrences and semantic place categorisation. A hierarchical model for representing object locations is presented with which the planner is able to perform indirect search. Finally we present real world experiments to show the feasibility of the approach.


Using Gaussian Process Regression for Efficient Motion Planning in Environments with Deformable Objects

AAAI Conferences

The ability to plan their own motions and to reliably execute them is an important precondition for autonomous robots. In this paper, we consider the problem of planning the motion of a mobile manipulation robot in the presence of deformable objects in the environment. Our approach combines probabilistic roadmap planning with a deformation simulation system. Since the physical deformation simulation is computationally demanding, we use an efficient variant of Gaussian process regression to estimate the deformation cost for individual objects based on training examples. We generate the training data by employing a simulation system in a preprocessing step. Consequently, no simulations are needed during runtime. We implemented and tested our approach on a mobile manipulation robot. Our experiments show that the robot is able to accurately predict and thus consider the deformation cost its manipulator introduces to the environment during motion planning. Simultaneously, the computation time is substantially reduced compared to a system that performs physical simulations online.


An Intelligent Load Balancing Algorithm Towards Efficient Cloud Computing

AAAI Conferences

MapReduce provided a novel computing model for complex job decomposition and sub-tasks management to support cloud computing with large distributed data sets. However, its performance is significantly influenced by the working data distributions over those data sets. In this paper, we put forward a novel model to balance data distribution to improve cloud computing performance in data-intensive applications, such as distributed data mining. By extending the classic MapReduce model with an agent-aid layer and abstracting working load requests for data blocks as tokens, the agents can reason from previously received tokens about where to send other tokens in order to balance the working tasks and improve system performance. Our key contribution lies in building an efficient token routing algorithm in spite of agents' unknowing to the global state of data distribution in cloud. We also built a prototype of our system, and the experimental results show that our approach can significantly improve the efficiency of cloud computing.


Load Balancing for Hypertable

AAAI Conferences

In Hypertable ranges of table data are stored and accessed on different nodes and allows for flexible management of the underlying hardware. Overall performance is sensitive to the balance of range load across the cluster. The project developers aim to create a simple interface to allow researchers to design experimental load balancing strategies that incorporate machine learning and optimization. This paper specifies the load balancing problem and introduces it as a challenge problem for AI and machine learning.


On the Cooling-Aware Workload Placement Problem

AAAI Conferences

This paper proposes a new challenging optimization problem, called COOLING-AWARE WORKLOADPLACEMENT PROBLEM, that looks for a workload placement that optimizes the overall data center power consumption given by the sum of the server power consumption and of the computer room air conditioner power consumption. We formulate CWPP as a Mixed Integer Non Linear Problem using a cross-interferencematrix that links the workload placement to the cold airtemperature. Since state-of-the-art Mixed Integer Non Linear solvers can solve to optimality only the smallest instances, we devised two heuristics to obtain good feasible solutions: (i) a heuristic algorithm based on an integer linear relaxation of the problem, and (ii) a VariableNeighborhood Search algorithm. Both heuristic algorithms are evaluated against the best lower bounds obtained with a Mixed Integer Non Linear solver. Preliminary computational results show that both heuristics provide solutions that have a small percentage gap from the optimal solutions.


Adaptable Fault Identification for Smart Buildings

AAAI Conferences

Malfunctioning HVAC equipment in commercial buildings wastes between 15% and 30% of energy. Many diagnosis approaches tackle this problem, but they either suffer from a lack of detailed fault information or a lack of adaptability to different buildings and equipment. Clearly, especially in the light of an ever increasing amount of sensor data that is available in heavily metered smart buildings, easily adaptable self learning in-depth diagnosis approaches are needed. This paper addresses the challenges of developing such approaches and describes the contribution artificial intelligence techniques like transfer learning, ontologies, knowledge representation or diagnosis can make in overcoming these challenges.


Mechanism Design for Aggregated Demand Prediction in the Smart Grid

AAAI Conferences

This paper presents a novel scoring rule-based mechanism that encourages agents to produce costly estimates of future events and truthfully report them to a centre when the budget for payments to the agents is itself determined by their reports. This is applied to a model of aggregated demand prediction within a microgrid where, given estimates of future consumptions, an aggregator must optimally purchase electricity for a set of homes, each represented by self-interested, rational home agents. This in turn reduces the need for costly standby generation within the grid. The aggregator has prior information about the amount each home will consume, and determines the amount to pay each agent based on savings resulting from using the agents' reported information, over its own prior information. Agents use sensory information regarding their property and its occupants to generate these estimates, which they transmit to the aggregator using smart grid technology. The proposed mechanism is dominant strategy incentive compatible and empirical evaluation shows that it encourages agents to exert effort in producing precise estimates. We show that the mechanism is ex ante individually rational for the aggregator, and that it outperforms a simpler mechanism whereby savings are distributed evenly.