Digital Simulation System Research Articles

Adaptive Multi-Function Radar Temporal Behavior Analysis

The performance of radar mode recognition has been significantly enhanced by the various architectures of deep learning networks. However, these approaches often rely on supervised learning and are susceptible to overfitting on the same dataset. As a transitional phase towards Cognitive Multi-Functional Radar (CMFR), Adaptive Multi-Function Radar (AMFR) possesses the capability to emit identical waveform signals across different working modes and states for task completion, with dynamically adjustable waveform parameters that adapt based on scene information. From a reconnaissance perspective, the valid signals received exhibit sparsity and localization in the time series. To address this challenge, we have redefined the reconnaissance-focused research priorities for radar systems to emphasize behavior analysis instead of pattern recognition. Based on our initial comprehensive digital system simulation model of a radar, we conducted reconnaissance and analysis from the perspective of the reconnaissance side, integrating both radar and reconnaissance aspects into environmental simulations to analyze radar behavior under realistic scenarios. Within the system, waveform parameters on the radar side vary according to unified rules, while resource management and task scheduling switch based on operational mechanisms. The target in the reconnaissance side maneuvers following authentic behavioral patterns while adjusting the electromagnetic space complexity in the environmental aspect as required. The simulation results indicate that temporal annotations in signal flow data play a crucial role in behavioral analysis from a reconnaissance perspective. This provides valuable insights for future radar behavior analysis incorporating temporal correlations and sequential dependencies.

Construction of a Digital Twin System and Dynamic Scheduling Simulation Analysis of a Flexible Assembly Workshops with Island Layout

Assembly Workshops with Island Layout (AWIL) possess flexible production capabilities that realize product diversification. To cope with the complex scheduling challenges in flexible workshops, improve resource utilization, reduce waste, and enhance production efficiency, this paper proposes a production scheduling method for flexible assembly workshops with an island layout based on digital twin technology. A digital twin model of the workshop is established according to production demands to simulate scheduling operations and deal with complex scheduling issues. A workshop monitoring system is developed to quickly identify abnormal events. By employing an event-driven rolling-window rescheduling technique, a dynamic scheduling service system is constructed. The rolling window decomposes scheduling problems into consecutive static scheduling intervals based on abnormal events, and a genetic algorithm is used to optimize each interval in real time. This approach provides accurate, real-time scheduling decisions to manage disturbances in workshop production, which can enhance flexibility in the production process, and allows rapid adjustments to production plans. Therefore, the digital twin system improves the sustainability of the production system, which will provide a theoretical research foundation for the real-time and unmanned production scheduling process, thereby achieving sustainable development of production.

Remote hands-on training with a novel "video-game" simulator for teaching fetoscopic laser techniques for ablation of placental anastomoses in twin-to-twin syndrome.

Key pointsWhat's already known about this topic? Twin to twin syndrome (TTTS) is a serious complication of monochorionic twin pregnancy The treatment of choice is fetoscopic laser ablation of placental anastamoses Simulation plays an important role in teaching this high‐acuity procedure What does this study add? We report the development of a high‐fidelity digital simulation system for teaching TTTS fetoscopic lasers Remote teaching has been demonstrated to work well with this system This simulator is robust, easy to store and assemble and relatively inexpensive.

Digitalization era of dental education: A systematic review.

Dental education is taking its share of the digitalization of the world. Therefore, it is of value to assess the use of the digital dental education system, especially in the undergraduate period. This systematic review concisely evaluated the use of augmented and virtual reality in preclinical dental education. The PICOS (Population, Intervention, Comparison, Outcome, and Study design) search strategy was used with the keywords 'e-learning', 'virtual reality' and 'preclinic simulation' to search the PubMed, PubMed Central, Web of Science, and Scopus databases. A total of 1,774 articles were found, and 45 articles were reviewed. The level of bias in the studies was also calculated. The studies were divided into 3 main groups: computer-assisted learning (C-AL); augmented reality-assisted learning (AR-AL); and virtual reality-assisted learning (VR-AL). Augmented and virtual reality are steadily evolving, and are increasingly being used in education and healthcare. The evaluated technological applications enable the visualization of medical information and provide clear feedback during the learning process with increased security and reliability; thus, digital simulation systems can be used to enhance students' abilities in dentistry.

Digital Simulation of Single Qubit Markovian Open Quantum Systems: A Tutorial

One of the first proposals for the use of quantum computers was the simulation of quantum systems. Over the past three decades, great strides have been made in the development of algorithms for simulating closed quantum systems and the more complex open quantum systems. In this tutorial, we introduce the methods used in the simulation of single qubit Markovian open quantum systems. It combines various existing notations into a common framework that can be extended to more complex open system simulation problems. The only currently available algorithm for the digital simulation of single qubit open quantum systems is discussed in detail. A modification to the implementation of the simpler channels is made that removes the need for classical random sampling, thus making the modified algorithm a strictly quantum algorithm. The modified algorithm makes use of quantum forking to implement the simpler channels that approximate the total channel. This circumvents the need for quantum circuits with a large number of CNOT gates.Quanta 2023; 12: 131–163.

Real Time Voltage Stability Estimation under Contingencies by Generalized Curve Fit Method using PMU

An accurate voltage stability monitoring scheme is necessary to take possible remedial action. Recent developments in Phasor Measurement Units (PMUs) technology provide the foundation for online voltage stability monitoring of a power system network. In this paper, the generalized curve fit method using PMUs in the system has been used to access voltage stability of the system and a sensitivity based approach has been used to identify critical buses of the system. Voltage stability margin has been obtained and compared using generalized curve fit method and continuation power flow method using PMUs in the system. Variations in voltage stability margin caused by changing load patterns have also been considered while estimating voltage stability under contingencies. Nose curves obtained using generalized curve fit and continuation power flow methods are also compared. Case studies have been performed on a standard IEEE 14-bus system and practical 246-bus Northern Regional Power Grid (NRPG) system representing power network of nine states of India, with the help of Real Time Digital Simulation (RTDS) and Power System Analysis Toolbox (PSAT) software.

Pilot protection method of half-wavelength AC transmission lines based on random matrix theory

The fault characteristics of ultra-high voltage (UHV) half-wavelength (HWL) transmission lines exhibit significant differences from those of conventional transmission lines, which renders the conventional relay protection method unsuitable for ensuring the protection of HWL. To solve this problem, a pilot protection method of HWTL based on random matrix theory was proposed. Voltage and current fault components obtained at the protection installation on both sides of the line were used as the input of the random matrix to form the singular value equivalent matrix, and the eigenvalues of the random matrix at both ends were calculated. The faults inside and outside the area were determined according to the distribution of the eigenvalues in the circular plane area. The protection scheme avoids the data synchronization problem at both ends of the line. Real time digital simulation system (RTDS) simulation revealed that the proposed protection method can protect the full length of the line, is suitable for various fault types and fault conditions, and exhibits excellent resistance to transition resistance.

Implementation of Control Standardization Based on HCM5000G DC Control and Protection Platform

This paper introduces the whole construction of the control standardization simulation system based on the HCM5000G DC control and protection platform, which can meet the requirements of engineering design and various control performance indexes by adopting the standardization design of the self-control and localization platform. In this paper, the construction principle of the standardized control system and the optimization strategy of the control structure are discussed in detail, and the engineering simulation model is realized by using the real-time digital simulation system with the layered and distributed standardized interface design, which provides an important reference for the future large-scale application of the control and protection of DC Engineering.

Development of a compact Ansatz via operator commutativity screening: Digital quantum simulation of molecular systems.

Recent advancements in quantum information and quantum technology have stimulated a good deal of interest in the development of quantum algorithms toward the determination of the energetics and properties of many-fermionic systems. While the variational quantum eigensolver is the most optimal algorithm in the noisy intermediate scale quantum era, it is imperative to develop compact Ansätze with low-depth quantum circuits that are physically realizable in quantum devices. Within the unitary coupled cluster framework, we develop a disentangled Ansatz construction protocol that can dynamically tailor an optimal Ansatz using the one- and two-body cluster operators and a selection of rank-two scatterers. The construction of the Ansatz may potentially be performed in parallel over multiple quantum processors through energy sorting and operator commutativity prescreening. With a significant reduction in the circuit depth toward the simulation of molecular strong correlation, our dynamic Ansatz construction protocol is shown to be highly accurate and resilient to the noisy circumstances of the near-term quantum hardware.

A digital twin-based machining motion simulation and visualization monitoring system for milling robot

A digital twin-based machining motion simulation and visualization monitoring system for milling robot

Efficient quantum simulation of electron-phonon systems by variational basis state encoder

Digital quantum simulation of electron-phonon systems requires truncating infinite phonon levels into $N$ basis states and then encoding them with qubit computational basis. Unary encoding and binary encoding are the two most representative encoding schemes, which demand $O(N)$ and $O(logN)$ qubits as well as $O(N)$ and $O(NlogN)$ quantum gates, respectively. In this paper, we propose a variational basis state encoding algorithm that reduces the scaling of the number of qubits and quantum gates to both $O(1)$ for systems obeying the area law of entanglement entropy. The cost for the scaling reduction is a constant amount of additional measurement. The accuracy and efficiency of the approach are verified by both numerical simulation and realistic quantum hardware experiments. In particular, we find using one or two qubits for each phonon mode is sufficient to produce quantitatively correct results across weak and strong coupling regimes. Our approach paves the way for practical quantum simulation of electron-phonon systems on both near-term hardware and error-corrected quantum computers.

Optimal compression of quantum many-body time evolution operators into brickwall circuits

Near term quantum computers suffer from a degree of decoherence which is prohibitive for high fidelity simulations with deep circuits. An economical use of circuit depth is therefore paramount. For digital quantum simulation of quantum many-body systems, real time evolution is typically achieved by a Trotter decomposition of the time evolution operator into circuits consisting only of two qubit gates. To match the geometry of the physical system and the CNOT connectivity of the quantum processor, additional SWAP gates are needed. We show that optimal fidelity, beyond what is achievable by simple Trotter decompositions for a fixed gate count, can be obtained by compiling the evolution operator into optimal brickwall circuits for the S=1/2S=1/2 quantum Heisenberg model on chains and ladders, when mapped to one dimensional quantum processors without the need of additional SWAP gates.

Research on Modeling Method for Excitation System of One Million-Kilowatt Unit in Nuclear Power Plant based on Real-Time Digital Simulation System

The excitation system is an important link between the generator set and the power grid. It is not only the key system to stabilize the operation of the generator set but also an important element related to the network. The accurate modeling and testing of the excitation system clarify and analyze the characteristics of the system. The traditional simulation software can only simulate the excitation system without the ability to test the control device and protection equipment. However, the real-time digital simulation system (RTDS) can realize real-time closed-loop tests of the hardware, which provides a new means for the excitation system analysis. This paper builds a detailed excitation system model of nuclear power units based on RTDS. The under-excitation limitation model is proposed based on the actual test data. Furthermore, the stability of the stator current limitation is improved by adding restriction conditions. Finally, the excitation system model is validated based on the measured data.

Cyberattack-Resilient Secondary Frequency Control Scheme for Stand-Alone Microgrids

This article proposes a cyberattack-resilient secondary frequency control (SFC) scheme for a stand-alone microgrid (MG) system. The proposed scheme is based on a hybrid system that employs an unknown input observer for state estimation, cyberattack detection and reconstruction, and a Type-2 fuzzy logic system for minimization of frequency deviation that may be caused by cyberattacks on the MG system. A cyberattack on the MG’s frequency measurement disrupts the operation of the SFC system and eventually compromises the frequency stability of the MG. The proposed approach shows an accurate estimation of the MG states and maintains the frequency of the MG within operating limits during various cyberattack scenarios. The practicability of the proposed hybrid scheme is validated using the Speedgoat real-time digital system simulator.

Analysis of the Digital System Simulation Levels for its Design Debugging

A brief analysis of the digital system design debugging is given, typical errors and inaccuracies of digital system designs at the development stage are listed. The levels of digital system design simulation are considered: simulation models at the level of queuing; register transfer level models; architecture and microarchitecture level models; quasi-timing logic diagram level models; models taking into account the spread of block delays. For each level of simulation, estimates of complexity and time costs are given, as well as the types of detected design errors.

Implementation of the XR Rehabilitation Simulation System for the Utilization of Rehabilitation with Robotic Prosthetic Leg

With the recent development of a digital rehabilitation system, research on the rehabilitation of amputees is accelerating. However, research on rehabilitation systems for patients with amputation of the lower extremities is insufficient. For the rehabilitation of amputees, it is important to maintain muscle mass through the improvement of muscle movement memory, continuous rehabilitation learning, and motivation to improve efficiency. The rehabilitation system in a virtual environment is convenient in that there is no restriction on time and space because rehabilitation training of amputees is possible without removing/attaching general prosthetic legs and robot prosthetic legs. In this paper, we propose an XR rehabilitation system for patients with lower extremity amputation to improve the motivational aspect of rehabilitation training. The proposed method is a system that allows patients and clinical experts to perform rehabilitation in the same environment using two XR equipment called HoloLens 2. The content was provided in the form of a game in which the number of movements of amputees was allocated as scores to enhance rehabilitation convenience and motivation aspects. The virtual 3D model prosthetic leg used in-game content worked through the acquisition and processing of the patient’s actual muscle EMG (ElectroMyoGraphy) signal. In order to improve reactivity, there was a time limit for completing the operation. The classified action should be completed by the amputee within the time limit, although the number of times set as the target. To complete the operation, the amputee must force the amputation area to exceed an arbitrarily set threshold. The evaluation results were evaluated through an independent sample t-test. we contribute to the development of digital rehabilitation simulation systems. XR rehabilitation training techniques, operated with EMG signals obtained from actual amputation sites, contribute to the promotion of rehabilitation content in patients with amputation of the lower extremities. It is expected that this paper will improve the convenience and rehabilitation of rehabilitation training in the future.

Virtual versus jaw simulation in inlay preparation preclinical teaching: a randomised controlled trial

BackgroundTo investigate the effect of virtual simulation systems on the teaching of inlay experiments and to guide the experimental teaching of tooth preparation.MethodsParticipants in their second semester of the junior year were selected to carry out the unified teaching and evaluation of dental preparation theory. The age varied from 18 to 22 years (19.96 ± 0.70) and the participants were randomly divided into four groups (n = 19) with a similar male-to-female ratio following CONSORT guidelines, including a jaw simulation model training group (Group J), a virtual simulation system training group (Group V), a jaw model training first followed by a virtual system training group (Group J-V), and a virtual system followed by a jaw model training group (Group V-J). The inlay tooth preparation assessment was performed on the extracted teeth. The data were analysed according to the assessment scores by a senior clinician. The subjective feelings of the students towards the system were evaluated using questionnaires.ResultsThe second theoretical scores of Group V-J (63.5 ± 2.89) and Group J-V (60.5 ± 3.25) were higher than those of Group V (57.5 ± 3.13) and Group J (58.0 ± 3.67). The experimental scores of Groups J-V and V-J (62.79 ± 2.84; 64.00 ± 2.85) were higher than those of Groups V and J (56.05 ± 3.39; 55.74 ± 2.53). The questionnaire survey illustrated that most students preferred the digital virtual simulation system (perfect assessment: 91.3%, accuracy: 82.6%, satisfaction: 52.2%).ConclusionVirtual simulation training can facilitate the teaching effect of tooth preparation in inlay experiments, and the teaching mode of Group V-J was the best. Therefore, this teaching mode is to be popularised.

A Decentralized Fault Section Location Method Using Autoencoder and Feature Fusion in Resonant Grounding Distribution Systems

In industrial applications, the existing fault location methods of resonant grounding distribution systems suffer from low accuracy due to excessive dependence on communication, lack of field data, difficulty in artificial feature extraction and threshold setting, etc. To address these problems, this study proposes a decentralized fault section location method, which is implemented by the primary and secondary fusion intelligent switch (PSFIS) with two preloaded algorithms: autoencoder (AE) and backpropagation neural network. The relation between the transient zero-sequence current and the derivative of the transient zero-sequence voltage in each section is analyzed, and its features are extracted adaptively by using AE, without acquiring network parameters or setting thresholds. The current and voltage data are processed locally at PSFISs throughout the whole procedure, making it is insusceptible to communication failure or delay. The feasibility and effectiveness of the approach are investigated in PSCAD/EMTDC and real-time digital simulation system, which is then validated by field data. Compared with other methods, the experiment results indicate that the proposed method performs well in various scenarios with strong robustness to harsh on-site environment and roughness of data.

Error-mitigated deep-circuit quantum simulation of open systems: Steady state and relaxation rate problems

Deep-circuit quantum computation, like Shor's algorithm, is undermined by error accumulation, and near-future quantum techniques are far from adequate for full-fledged quantum error correction. Instead of resorting to shallow-circuit quantum algorithms, recent theoretical research suggests that digital quantum simulation (DQS) of closed quantum systems are robust against the accumulation of Trotter errors, as long as local observables are concerned. In this paper, we investigate digital quantum simulation of open quantum systems. First, we prove that the deviation in the steady state obtained from digital quantum simulation depends only on the error in a single Trotter step, which indicates that error accumulation may not be disastrous. By numerical simulation of the quantum circuits for the DQS of the dissipative XYZ model, we then show that the correct results can be recovered by quantum error mitigation as long as the error rate in the DQS is below a sharp threshold. We explain this threshold behavior by the existence of a dissipation-driven quantum phase transition. Finally, we propose a new error-mitigation technique based on the scaling behavior in the vicinity of the critical point of a quantum phase transition. Our results expand the territory of near-future available quantum algorithms and stimulate further theoretical and experimental efforts in practical quantum applications.

A novel distance protection scheme using single‐ended transient voltage based on generalized S transform

Concerning the distance protection steady-state over-reach or under-reach caused by the transition resistance, a novel distance protection scheme based on transient information is proposed. First, multiple fault features are extracted using the Generalized Stockwell Transform (GST), and a criterion for identifying low-resistance and high-resistance ground faults is constructed. Then, a GST coefficient matrix is established for the single-ended transient voltage of the line, the attenuation coefficient and delay coefficient are derived by the least-squares method and the beat phenomenon, and the transition resistance is calculated. On this basis, adjust the operation boundary in the +R axis direction of the operation zone according to the transition resistance value. Finally, test results on real-time digital simulation system (RTDS) demonstrate that the protection scheme operates reliably in different fault cases and is highly immune to fault resistance. Compared with the traditional distance protection scheme, this scheme performs better when the transition resistance is large.