Control Strategies for Digital Twin Systems

With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical applications.To make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples.

Iterative Learning Control for Discrete-time Stochastic Systems with Quantized Information

An iterative learning control (ILC) algorithm using quantized error information is given in this paper for both linear and nonlinear discrete-time systems with stochastic noises. A logarithmic quantizer is used to guarantee an adaptive improvement in tracking performance. A decreasing learning gain is introduced into the algorithm to suppress the effects of stochastic noises and quantization errors. The input sequence is proved to converge strictly to the optimal input under the given index. Illustrative simulations are given to verify the theoretical analysis. © 2014 Chinese Association of Automation.

Transfer Function Model of Multirate Feedback Control Systems

Based on the suitably defined multivariable version of Kranc operators and the extended input and output vectors, the multirate sampling plant is transformed to a equivalent time invariant single rate one, then the transfer function model of the multivariable multirate sampling plant is obtained. By combining this plant model with the time invariant description of the multirate controller in terms of extended vectors, the closed loop transfer function model of the multirate feedback control system can be determinated. This transfer function model has a very simple structure, and can be used as a basis for the analysis and synthesis of the multirate sampling feedback control systems in the frequency domain.

Building digital life systems for future biology and medicine

The rapid development of biological technology (BT) and information technology (IT) especially of genomics and artificial intelligence (AI) is bringing great potential for revolutionizing future medicine. We propose the concept and framework of Digital Life Systems or dLife as a new paradigm to unleash this potential. It includes the multi-scale and multi-granule measure and representation of life in the digital space, the mathematical and/or computational modeling of the biology behind physiological and pathological processes, and ultimately cyber twins of healthy or diseased human body in the virtual space that can be used to simulate complex biological processes and deduce effects of medical treatments. We advocate that dLife is the route toward future AI precision medicine and should be the new paradigm for future biological and medical research.

Improvement of Injection-Locked VCSELs for Analog and Digital Communication Systems

VCSEL Injection locking is demonstrated to increase laser bandwidth and reduce non-linearity and chirp. All these properties enhance analog and digital modulation performance.

PARALLEL COMPUTATIONAL ALGORITHM OF SUBSTRUCTURE METHOD OF LARGE-SCALE STRUCTURE ANALYSIS

In this paper, according to the parallel environment of ELXSI computer, a parallel solving process of substructure method in static and dynamic analyses of large-scale and complex structure has been put forward, and the corresponding parallel computational program has been developed.

Conformal electrodes for on-skin digitalization

On-skin digitalization,streamlining the concept of the“human to device to cyberspace”platform,has attracted great attention due to its vital function in remote medicine and human-cyber interfaces.Beyond traditional rigid electrodes,soft electrodes with conformal and comfortable interfaces are essential for long-term and high-fidelity signal acquisition.In addition,the on-skin data processing systems will get rid of complex cables toward a vision of fascinating form,being lightweight,skin-friendly and even imperceptible.Although numerous soft materials and devices with mechanical tolerance have been developed,the study of conformal electrodes and on-skin digital integrated systems are still in infancy.Here,the requirements and designs of conformal electrodes,the emerging opportunities and challenges from multichannel/multifunctional sensors to a whole new on-skin sensing platform are highlighted.

Adaptive suppression of passive intermodulation in digital satellite transceivers

For the performance issues of satellite transceivers suffering passive intermodulation interference,a novel and effective digital suppression algorithm is presented in this paper.In contrast to analog approaches,digital passive intermodulation（PIM） suppression approaches can be easily reconfigured and therefore are highly attractive for future satellite communication systems.A simplified model of nonlinear distortion from passive microwave devices is established in consideration of the memory effect.The multiple high-order PIM products falling into the receiving band can be described as a bilinear predictor function.A suppression algorithm based on a bilinear polynomial decorrelated adaptive filter is proposed for baseband digital signal processing.In consideration of the time-varying characteristics of passive intermodulation,this algorithm can achieve the rapidness of online interference estimation and low complexity with less consumption of resources.Numerical simulation results show that the algorithm can effectively compensate the passive intermodulation interference,and achieve a high signal-to-interference ratio gain.

Energy-efficiency based downlink multi-user hybrid beamforming for millimeter wave massive MIMO system

The fifth generation mobile communication（5G） systems can provide Gbit/s data rates from massive multiple-input multiple-output（MIMO） combined with the emerging use of millimeter wavelengths in small heterogeneous cells. This paper develops an energy-efficiency based multi-user hybrid beamforming for downlink millimeter wave（mm Wave） massive MIMO systems. To make better use of directivity gains of the analog beamforming and flexible baseband processing of the digital beamforming, this paper proposes the analog beamforming to select the optimal beam which can maximize the power of the objective user and minimize the interference to all other users. In addition, the digital beamforming maximizes the energy efficiency of the objective user with zero-gradient-based approach. Simulation results show the proposed algorithm provide better bit error rate（BER） performance compared with the traditional hybrid beamforming and obviously improved the sum rate with the increase in the number of users. It is proved that multi-user MIMO（MU-MIMO） can be a perfect candidate for mm Wave massive MIMO communication system. Furthermore, the analog beamforming can mitigate the inter-user interference more effectively with the selection of the optimal beam and the digital beamforming can greatly improve the system performance through flexible baseband processing.

TAUS: A File-Based Software Understanding Tool

A program called TAUS, a Tool for Analyzing and Understanding Software, was developed. It is de- signed to help the programmer analyze and understand the software interactively. Its aim is to reduce the depen- dence on human intelligence in software understanding and improve the programmer's understanding productivity. The design and implementation of TAUS and its application are described.

On the Execution Mechanisms of Parallel Graph Reduction

Parallel graph reduction is a promising model for new generation computer because of its amenability to both programming and parallel computing. In this paper, an initial design for a parallel graph reduction model, PGR model, is presented, which employs eager evaluation strategy to exploit conservative parallelism and provides with primitives and associated tags of nodes to synchronize concurrent tasks .Moreover, a direct operational description of graph reduction in terms of high level instructions (primitives) is given to obtain a virtual machine, called PGRVM.

Communication Analysis and Granularity Assessment for a Transputer-Based System

This paper exposes the concurrent characteristic in the communication between processors in a transputer based system, and proposes an approximate formula for assessing the granularity of distributing the parallel processes among processors. The really measured results for a pipeline sorting program running on the T-rack confirm these deduced results.

TST——An Algorithm for Global Microcode Compaction with Timing Constraints

Existing global microcode compaction approaches have all assumed a target architecture that has microoperation conflicts and data dependencies as the two fundamental compaction constraints.However, new practical micromachine features demand that the timing constraint be introduced into the traditional compaction model to guarantee compaction correctness.This paper starts by an analysis on the nature of timing constraints,then modifies the roles for microoperation motions,presents an algorithm,TST,based on Trace Scheduling,for global compaction under timing constraints,and finally shows results of experiments.