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1. Invited paper: An Efficient Energy Management Solution for Renewable Energy Based IoT Devices

   https://doi.org/10.1145/3571306.3571387  

   Liri, Elizabeth; Ramakrishnan, K. K.; Kar, Koushik; Lyon, Geoff; Sharma, Puneet (January 2023, ICDCN '23: Proceedings of the 24th International Conference on Distributed Computing and Networking)

   Multi-sensor IoT devices enable the monitoring of different phenomena using a single device. Often deployed over large areas, these devices have to depend on batteries and renewable energy sources for power. Therefore, efficient energy management solutions that maximize device lifetime and information utility are important. We present SEMA, a smart energy management solution for IoT applications that uses a Model Predictive Control (MPC) approach to optimize IoT energy use and maximize information utility by dynamically determining task values to be used by the IoT device’s sensors. Our solution uses the current device battery state, predicted available solar energy over the short-term, and task energy and utility models to meet the device energy goals while providing sufficient monitoring data to the IoT applications. To avoid the need for executing the MPC optimization at a centralized sink (from which the task values are downloaded to the SEMA devices), we propose SEMA-Approximation (SEMA-A), which uses an efficient MPC Approximation that is simple enough to be run on the IoT device itself. SEMA-A decomposes the MPC optimization problem into two levels: an energy allocation problem across the time epochs, and task-dependent sensor scheduling problem, and finds efficient algorithms for solving both problems. Experimental results show that SEMA is able to adapt the task values based on the available energy, and that SEMA-A closely approximates SEMA in sensing performance. 

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2. Adaptive Activity Monitoring with Uncertainty Quantification in Switching Gaussian Process Models

   Randy Ardywibowo, Guang Zhao (April 2019, Proceedings of Machine Learning Research)

   Emerging wearable sensors have enabled the unprecedented ability to continuously monitor human activities for healthcare purposes. However, with so many ambient sensors collecting different measurements, it becomes important not only to maintain good monitoring accuracy, but also low power consumption to ensure sustainable monitoring. This power-efficient sensing scheme can be achieved by deciding which group of sensors to use at a given time, requiring an accurate characterization of the trade-off between sensor energy usage and the uncertainty in ignoring certain sensor signals while monitoring. To address this challenge in the context of activity monitoring, we have designed an adaptive activity monitoring framework. We first propose a switching Gaussian process to model the observed sensor signals emitting from the underlying activity states. To efficiently compute the Gaussian process model likelihood and quantify the context prediction uncertainty, we propose a block circulant embedding technique and use Fast Fourier Transforms (FFT) for inference. By computing the Bayesian loss function tailored to switching Gaussian processes, an adaptive monitoring procedure is developed to select features from available sensors that optimize the trade-off between sensor power consumption and the prediction performance quantified by state prediction entropy. We demonstrate the effectiveness of our framework on the popular benchmark of UCI Human Activity Recognition using Smartphones. 

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3. DARC: Disturbance-Aware Redundant Control for Human–Robot Co-Transportation

   https://doi.org/10.3390/electronics14122480  

   Mahmud, Al Jaber; Raj, Amir Hossain; Nguyen, Duc M; Xiao, Xuesu; Wang, Xuan (June 2025, Electronics)

   This paper introduces Disturbance-Aware Redundant Control (DARC), a control framework addressing the challenge of human–robot co-transportation under disturbances. Our method integrates a disturbance-aware Model Predictive Control (MPC) framework with a proactive pose optimization mechanism. The robotic system, comprising a mobile base and a manipulator arm, compensates for uncertain human behaviors and internal actuation noise through a two-step iterative process. At each planning horizon, a candidate set of feasible joint configurations is generated using a Conditional Variational Autoencoder (CVAE). From this set, one configuration is selected by minimizing an estimated control cost computed via a disturbance-aware Discrete Algebraic Riccati Equation (DARE), which also provides the optimal control inputs for both the mobile base and the manipulator arm. We derive the disturbance-aware DARE and validate DARC with simulated experiments with a Fetch robot. Evaluations across various trajectories and disturbance levels demonstrate that our proposed DARC framework outperforms baseline algorithms that lack disturbance modeling, pose optimization, or both. 

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4. Periodic multi-agent persistent monitoring of a finite set of targets with uncertain states

   Pinto, Samuel C.; Andersson, Sean B; Hendrickx, Julien M; Cassandras, Christos G (January 2020, 2020 American Control Conference)

   We investigate the problem of persistently monitoring a finite set of targets with internal states that evolve with linear stochastic dynamics using a finite set of mobile agents. We approach the problem from the infinite-horizon perspective, looking for periodic movement schedules for the agents. Under linear dynamics and some standard assumptions on the noise distribution, the optimal estimator is a Kalman- Bucy filter. It is shown that when the agents are constrained to move only over a line and they can see at most one target at a time, the optimal movement policy is such that the agent is always either moving with maximum speed or dwelling at a fixed position. Periodic trajectories of this form admit finite parameterization, and we show to compute a stochastic gradient estimate of the performance with respect to the parameters that define the trajectory using Infinitesimal Perturbation Analysis. A gradient-descent scheme is used to compute locally optimal parameters. This approach allows us to deal with a very long persistent monitoring horizon using a small number of parameters. 

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5. Sensing-motion co-planning for reconstructing a spatially distributed field using a mobile sensor network

   https://doi.org/10.1109/CDC.2017.8264114  

   You, Jie; Wu, Wencen (December 2017, 56th IEEE Conference on Decision and Control)

   We investigate the problem of simultaneous parameter identification and mapping of a spatially distributed field using a mobile sensor network. We first develop a parametrized model that represents the spatially distributed field. Based on the model, a recursive least squares algorithm is developed to achieve online parameter identification. Next, we design a global state observer, which uses the estimated parameters, together with data collected by the mobile sensor network, to real-timely reconstruct the whole spatial-temporal varying field. Since the performance of the parameter identification and map reconstruction algorithms depends on the trajectories of the mobile sensors, we further develop a Lyapunov redesign based online trajectory planning algorithm for the mobile sensor network so that the mobile sensors can use local real-time information to guide them to move along information-rich paths that can improve the performance of the parameter identification and map construction. Lastly, a cooperative filtering scheme is developed to provide the state estimates of the spatially distributed field, which enables the recursive least squares method. To test the proposed algorithms in realistic scenarios, we first build a CO2 diffusion field in a lab and construct a sensor network to measure the field concentration over time. We then validate the algorithms in the reconstructed CO2 field in simulation. Simulation results demonstrate the efficiency of the proposed method. 

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