Human attention is a dynamic and limited resource, essential for navigating complex tasks and environments. In the digital age, this resource is increasingly strained by frequent task switching, driven by constant notifications and fragmented workflows. While the cognitive costs of task switching are well-documented, its implications for digital privacy remain underexplored. This study investigates a novel privacy threat: the inference of task switching from network traffic by network service providers. We demonstrate that behavioral signatures, such as task durations and switching patterns, can be extracted from temporal metadata, potentially revealing sensitive information about users’ cognitive states and habits. We introduce a machine learning-based approach to infer these patterns and empirically validate its effectiveness on network traffic traces. To counter this threat, we propose a mitigation strategy that obfuscates task-switching signals without substantially impacting network performance. Our findings bridge cognitive science and network security, highlighting a new dimension of privacy risk in modern digital infrastructures and offering practical pathways toward more privacy-preserving communication systems.

This paper presents a novel control approach, based on the interconnection and damping-assignment passivity-based control (IDA-PBC), to achieve stable and periodic walking for underactuated planar biped robots with one degree of underactuation. The system's physical structure is preserved by assigning a target port-Hamiltonian dynamics to the closed-loop system, which also ensures passivity. The control design ensures that the tracking error to the desired periodic gait converges exponentially to zero, and the convergence rate can be adjusted via gain tuning. Besides, through the hybrid zero dynamics, the stability of the full-order system can be retrieved from the stability of the orbit created in a lower-dimensional manifold. The proposed approach is the first example of a tracking controller based on the IDA-PBC applied to underactuated biped robots. Numerical simulations on a five-link planar biped robot with unactuated ankles validate the approach and show the performance of the closed-loop system.

In modern robotics, the manipulators are no longer isolated under fully controlled conditions but rather conceived to work in unconstrained environments. Under these operations, compliant control and passivity properties of the robot are of great importance, and thus the system’s energy function plays a crucial role in the control design. In this work, we propose a new design of cartesian impedance control for a flexible robot whose dynamics is represented within the port-Hamiltonian framework. To improve the performance of the system and maximize the capabilities of the robot, the robotic control system is enhanced with energy tanks that allow for temporarily non-passive operations, but ensure the passivity of the extended system. In addition, a secondary controller is designed using the port-Hamiltonian approach to cover the case of redundant robotic manipulators. The performance of the full control system is tested via simulations of the Kuka iiwa manipulator in closed loop with the proposed passivity-based controller. The results show a satisfactory performance of the control system for set-point regulation, external forces, time-varying reference trajectories, and parametric uncertainty.

This paper presents a new procedure to design a control law using the classical interconnection and damping assignment technique within the passivity-based port-Hamiltonian framework. The sought goal is to reduce the complexity of solving the so-called matching equations. The proposed approach is applied to two case studies of planar rolling nonprehensile manipulation, namely, the ball-and-beam and the eccentric disk-on-disk. The performance of the resulting controllers is illustrated through both simulations and experimental results, showing the applicability of the design in a real setup.

In this paper, we present the design of a robust interconnection and damping assignment controller for a rolling-balancing system known as the disk-on-disk. The underactuation feature of this system hampers the control design, and since we consider matched disturbances, the problem becomes even more challenging. To overcome this difficulty, we propose to design first a controller to stabilize the desired equilibrium of the case where the disturbance is not present, and then we robustify this controller by adding a nonlinear PID outer loop that compensates the disturbance. Finally, we evaluate the practical applicability of the control design by implementing the controllers on a real hardware for the disk-on-disk system.

In this paper, we address the problem of stabilisation of robots subject to nonholonommic constraints and external disturbances using port-Hamiltonian theory and smooth time-invariant control laws. This should be contrasted with the commonly used switched or time-varying laws. We propose a control design that provides asymptotic stability of an manifold (also called relative equilibria)-due to the Brockett condition this is the only type of stabilisation possible using smooth time-invariant control laws. The equilibrium manifold can be shaped to certain extent to satisfy specific control objectives. The proposed control law also incorporates integral action, and thus the closed-loop system is robust to unknown constant disturbances. A key step in the proposed design is a change of coordinates not only in the momentum, but also in the position vector, which differs from coordinate transformations previously proposed in the literature for the control of nonholonomic systems. The theoretical properties of the control law are verified via numerical simulation based on a robotic ground vehicle model with differential traction wheels and non co-axial centre of mass and point of contact.