Multi-state Cells Research Articles

15～45 GHz 고해상도 소형 분산형 디지털 감쇠기

This paper describes the design and measurement of a compact distributed digital attenuator using multi-state cells. The attenuator consists of four multi-state cells with different attenuation states. To improve linearity, a stacked-FET topology, in which four transistors are stacked, is applied to the parallel transistors of multi-state cells. In addition, grounded T-lines are inserted to the source of parallel transistors to compensate the phase error. The size of parallel transistors is optimized to implement a 0.5-dB attenuation step and to remove the coupling effect of the previously proposed compact distributed digital attenuator. The attenuator showed a measured 14-dB maximum attenuation range and 0.5-dB attenuation step in a frequency range of 15～45 GHz. The RMS amplitude error and RMS phase error were 0.1～1.4 dB and 1.7～4°, respectively.

Quasiequilibrium multistate cellular automata.

In our effort to tackle the problem of letting nontrivial interactions, thermodynamic equilibrium, and full synchronicity coexist, and in the hope of reviving interest in cellular automata as promising tools for the quantitative, large-scale investigation of multiparticle systems, we built a fully synchronous cellular automaton rule for the simulation of occupancy-based lattice systems with multistate cells and neighboring interactions. The core of this rule, which constitutes an actual synchronous sampling scheme, is a negotiation stage; it produces cell occupancy distributions in very good agreement with their sequential Monte Carlo counterparts, and it satisfies a cellwise detailed balance principle thanks to the use of "mixed" intermediate states that allow for the computation of locally averaged acceptance probabilities. We took a square lattice (but the rule itself is not bound by dimensionality) as a basis for comparison with sequential Monte Carlo for showing that this synchronous rule leads to quasiequilibrium; the fulfillment of cellwise detailed balance is shown through results obtained for a small one-dimensional system, where the transition matrix could be computed exactly.

Stochastic recruitment control of shape memory alloy cellular actuators based on multi-state Markov chain model

A new broadcast stochastic recruitment approach to the control of shape memory alloy (SMA) cellular actuators is proposed. The control design is based on a Markov chain model of multi-state cells, which is able to better characterize the inherent hysteresis of SMA in phase transition. The closed-loop and open-loop control laws are derived from random Lyapunov stability analysis and the stability conditions are analyzed. Simulation experiments demonstrate the effectiveness of the proposed method.

Stochastic recruitment limited control of shape memory alloy based on Markov chain model

A new control method of Shape Memory Alloy (SMA) actuators based on stochastic recruitment is proposed. From the perspective of bionic control, the physiological basis of stochastic recruitment limited feedback control of artificial muscle is explained. The limited feedback control system of two-state cells and multi-state cells are established, and the limited feedback control law is deduced for these two kinds of systems. In the Simulink environment, two kinds of limited feedback control algorithms are simulated and compared, which verifies the feasibility of the algorithm. Aiming at the key problem of scaling coefficient in the system, the longitudinal and transverse comparative experiments are carried out to analyze the influence of the scaling coefficient on the system.