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Electrical Impedance Tomography (EIT) systems have shown great promise in many fields such as real-time wearable healthcare imaging, but their fixed number of electrodes and placement locations limit the system's flexibility and adaptability for further advancement. In this article, we propose a flexible and reconfigurable EIT system (Flexi-EIT) based on digital active electrode (DAE) architecture to address these limitations. By integrating a reconfigurable number of up to 32 replaceable DAEs into the flexible printed circuit (FPC) based wearable electrode belt, we can enable rapid, reliable, and easy placement while maintaining high device flexibility and reliability. We also explore hardware-software co-optimization image reconstruction solutions to balance the size and accuracy of the model, the power consumption, and the real-time latency. Each DAE is designed using commercial chips and fabricated on a printed circuit board (PCB) measuring 13.1 mm × 24.4 mm and weighing 2 grams. In current excitation mode, it can provide programmable sinusoidal current signal output with frequencies up to 100 kHz and amplitudes up to 1 mA$_{p-p}$ that meets IEC 60601-1 standard. In voltage acquisition mode, it can pre-amplify, filter, and digitize the external response voltage signal, improving the robustness of the system while avoiding the need for subsequent analog signal processing circuits. Measured results on a mesh phantom demonstrate that the Flexi-EIT system can be easily configured with different numbers of DAEs and scan patterns to provide EIT measurement frames at 38 fps and real-time EIT images with at least 5 fps, showing the potential to be deployed in a variety of application scenarios and providing the optimal balance of system performance and hardware resource usage solutions.

Symbiotic radio is a new communication paradigm for improving spectrum efficiency and system capacity. However, most of the existing resource allocation algorithms do not consider the impact of channel estimation errors and information leakage. To improve transmission security and robustness, in this letter, we investigate a robust secure resource allocation problem for a downlink multiuser symbiotic radio network with imperfect channel station information (CSI) and eavesdroppers. Based on bounded CSI error models, the overall throughput is maximized subject to the secure rate constraints, the maximum transmit power constraint, the time allocation constraint, and the reflection coefficient constraints. Moreover, the worst-case approach, the variable substitution approach, and Lagrange dual theory are applied to convert the originally non-convex problem into a convex one, where the closed-form solutions are solved by using the subgradient method. Simulation results verify the proposed algorithm has higher satisfaction probabilities and secure transmission rates.

Process, voltage, and temperature (PVT) variations in chip fabrication or operation pose a significant challenge to the robustness of analog integrated circuits. Existing design techniques for mitigating PVT variations involve analyzing offsets of DC operating points, but this approach often leads to compromises in circuit performance. To address this challenge, we developed a ‘PVT-Transfer’ framework to facilitate knowledge transfer with evolutionary design. Specifically, by cross-operating the circuit parameters under variations, design knowledge is transferred through parameter migration, thus enhancing the robustness of the resultant circuit. In addition, we leverage data-driven learning to discover potential similarities among PVT variations, thereby mitigating negative knowledge transfer. The PVT-Transfer Framework is evaluated on three integrated voltage references and compared with four state-of-the-art circuit sizing methods. Based on post-layout Monte-Carlo simulations, this framework is verified to offer superior performance to existing methods, yielding a 60% reduction in power consumption, an 80% increase in temperature resilience, and up to $70\times $ enhancement in the figure of merit. Further, it leads to a 60% reduction in the number of required circuit simulations and is suitable for parallel computation.

This brief presents a reconfigurable multifunctional logic standard cell that offers a new design methodology in the engineering change order (ECO) process to reduce the design risks and nonrecurring engineering (NRE) cost and enhance its current performances. Based on the self-dual graph theory, we have implemented multiple logic (XOR, XNOR, NAND, NOR, AND, and OR) functions in a complementary H-bridge standard cell circuit. A dynamic logic architecture is adopted to reduce the operating supply voltage and active area. Fabricated in a 55-nm CMOS technology, the measurement results have validated the functionality of the proposed circuit under 0.3- to 1.2-V supply voltage. The average propagation delay and power consumption are 82 ns and 0.26 nW, respectively, at a supply voltage of 0.3 V and clock frequency of 1 MHz. An ECO flow is developed based on the proposed reconfigurable standard cell. The results indicate that the proposed reconfigurable standard cell reduces the required number of ECO cells by 1.8-3.6 times.

In this paper, a hierarchical control strategy of vehicle platoons is presented, in which the longitudinal and lateral coupling property of vehicles is taken into account. A three-degree-of-freedom dynamic model of vehicles is approximated to a “global” linear model by the Koopman operator theory. A synchronous distributed predictive control scheme of vehicle platoons is proposed as an upper-level controller, where both the linear vehicle model and a linear parametric-varying lane-keeping model are adopted to predict the dynamic of vehicles, and keep vehicles in the designated lane. Thus, it can avoid the solution of nonlinear optimization problems and reduce the computational burden accordingly. A lower-level controller is designed, where the desired longitudinal control force determined by the upper-level controller is transformed into the desired throttle angle and brake pressure through an inverse longitudinal dynamics model of vehicles. The joint simulation results by PreScan, CarSim and MATLAB/Simulink show that when the leader vehicle accelerates or decelerates, the following vehicles in the platoon can keep the same velocity as the leader vehicle, and maintain the desired safety distance between the front and rear vehicles. In addition, joint simulation in the curved road scenario show that the performance of lane keeping can be guaranteed for vehicle platoons with the proposed control strategy.