State Of System Research Articles

Discrete adaptive sliding mode controller design for overhead cranes considering measurement noise and external disturbances

AbstractResearch on the motion control of overhead cranes, constrained by underactuated characteristics, helps improve the efficiency of payload transportation. Most studies require all system state variables (trolley displacement, payload swing angle, and their velocities). In practice, sensors measure and transmit these variables, but noise affects their accuracy, reducing control performance. Additionally, uncertainties in crane parameters, unmodeled friction, and unknown disturbances threaten the system's stability. Traditional methods struggle to address these issues effectively. To address these challenges, this article proposes an adaptive discrete sliding mode control (DSMC) method with a Kalman filter. By extending the state system and considering disturbances as new variables, the Kalman filter effectively eliminates signal noise, accurately estimates disturbances, and estimates system states simultaneously. The proposed method incorporates disturbance compensators into the adaptive DSMC, utilizing exponential terms to suppress oscillations caused by excessively high or low control gains, thus increasing control speed. Experimental comparisons demonstrate the superiority and robustness of the proposed control method under various disturbance conditions.

Fusion of atomic W-like states in cavity QED systems

Fusion of atomic W-like states in cavity QED systems

Few-femtosecond soft X-ray transient absorption spectroscopy with tuneable DUV-Vis pump pulses

Achieving few-femtosecond resolution for a pump-probe experiment is crucial to measuring the fastest electron dynamics and for creating superpositions of valence states in quantum systems. However, traditional UV-Vis pump pulses cannot achieve few-fs durations and usually operate at fixed wavelengths. Here, we present, to our knowledge, an unprecedented temporal resolution and pump tuneability for UV-Vis-pumped soft X-ray transient absorption spectroscopy. We have combined few-fs deep-UV to visible tuneable pump pulses from resonant dispersive wave emission in hollow capillary fiber with attosecond soft X-ray probe pulses from high harmonic generation. We achieve sub-5-fs time resolution, sub-fs interferometric stability, and continuous tuneability of the pump pulses from 230 to 700 nm. We demonstrate that the pump can initiate an ultrafast photochemical reaction and that the dynamics at different atomic sites can be resolved simultaneously. These capabilities will allow studies of the fastest electronic dynamics in a large range of photochemical, photobiological and photovoltaic reactions.

Enhancing operational performance assessment of structures with seismic response modification devices: The role of observability and symmetry analysis under limited sensor deployment

AbstractTo manage structural responses under various external forces, the increasing incorporation of seismic isolation and supplementary damping systems in modern civil engineering necessitates post‐installation performance assessments. The challenge of accurately inferring system information from these complex dynamical structures, especially with limited sensor deployment, could be significant. From the perspective of solving inverse problems, this challenge hinges on constructing an input‐output mapping that assures unique solutions, achievable through theoretical observability or symmetry analysis. We introduce a unified algorithm framework designed to accommodate various definitions of Lie derivatives, specifically for observability and symmetry analysis in dynamic systems with affine, non‐affine, and unknown inputs—capabilities not fully achieved in previous studies. We demonstrate its application across typical dynamic scenarios, including both linear and nonlinear examples. We also present a numerical example featuring complex isolation systems with limited sensor layouts, illustrating how uniform convergence can be achieved in estimating all system states when an observable input‐output mapping is utilized. Furthermore, an experimental example employing shaking table tests showcases the potential complications that arise when an unobservable input‐output mapping is used.

Unstructured environment navigation and trajectory calibration technology based on multi-data fusion

In order to effectively improve the accuracy and efficiency of unstructured environment navigation and trajectory calibration, a multi data fusion based unstructured environment navigation and trajectory calibration method was studied. Described the basic principles of the Strapdown Inertial Navigation System and Doppler Log. After introducing DVL velocity information and relative position information of underwater robots into SINS, the Kalman filter fusion algorithm was used to obtain the system's state equation and measurement equation. The navigation parameter error and device error parameters of the system were selected as the state variables. The difference between SINS output speed and DVL measurement speed, as well as the difference between SINS output position and relative position, are used as the speed and position measurements of the measurement system. Error estimation is obtained through indirect filtering, and the accuracy of navigation and positioning is improved through output correction. The experimental results show that the proposed method has a good calibration effect and can effectively improve the accuracy and efficiency of trajectory calibration in unstructured environments.

Divergent response of Chernozem organic matter towards short-term water stress in Poa pratensis L. rhizosphere and bulk soil in pot experiments: A spectroscopic study

Understanding and controlling rhizospheric processes under abiotic stress is one of the key challenges in addressing food security amid the climate crisis. In this work, the impact of short-term drought and overwatering on soil organic matter (SOM) of Haplic Chernozem in the rhizosphere of Poa pratensis L. and in bulk soil was investigated. The vegetation experiment was conducted in a climatic chamber at soil moisture levels of 35, 80, and 200 % of the field capacity. UV-Vis and spectrofluorometry were used to describe the water-extractable organic matter (WEOM) characteristics and fluorofores signature, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to describe functional group composition of SOM. Composition and properties of SOM and WEOM of Chernozem significantly change after exposure to short-term water stress. Drought does not affect the composition of rhizosphere SOM except increasing the proportion of polysaccharides, but leads to the decrease in aromaticity and increase in molecular weight of humic-like components of rhizosphere WEOM. These findings reflect Poa adaptation to water deficiency and microbial activity suppression which results in accumulation of SOM intermediate decomposition products. On the contrary, bulk WEOM wasn't affected by drought but SOM became enriched with aromatic and oxidised components. Overwatering leads to equalisation of bulk and rhizospheric SOM composition due to a decrease in the proportion of aromatic and carboxylic components of bulk SOM and the accumulation of microbial products in both bulk and rhizospheric SOM. In general, rhizospheric WEOM undergoes relatively significant changes relative to the optimum water regime under moisture deficit, and bulk WEOM — under overwatering. The findings illustrate the involvement of the both WEOM and SOM in maintaining resilience of the soil-plant system as well as the difference in watering conditions impact on SOM in rhizosphere and bulk soil. SOM spectral data can be used for assessing the state of soil systems, such as changes in microbial activity and adaptation of the soil-plant system to abiotic stress. Our findings also illustrate the differences in the organic matter transformation of the Poa pratensis rhizosphere and the bulk Chernozem depending on environmental factors.

The Current State of the Russian Financial System: New Vectors of Legal Regulation of the Financial Market

The scientific work is devoted to the current state of the Russian financial system. The first part of the study provides empirical data on budget revenues and expenditures as a macro-legal institution in characterizing the state of the Russian financial system. In the second part — new vectors of legal regulation of the financial market — an attempt is made to resolve the academic dispute about the core consolidation of state and municipal borrowing from the position of goal-setting of the financial market.

Periodicity alters topological states in thermal diffusion system

Topological edge states are a ubiquitous phenomenon across diverse wave systems, including electromagnetic, acoustic and quantum systems. In contrast to wave systems, thermal transport is a kind of diffusion system characterized by pure dissipation. The imposition of different boundary conditions can significantly influence the evolution of thermal system, leading to the appearance of different topological states, which haven't been systematically analyzed yet, especially in practical heat transfer structures. In this work, via a non-Hermitian thermal diffusion lattice model, we discuss the periodicity-dependent topological states. Through rigorous theoretical analysis and numerical simulations of the temperature field, the Hamiltonian is obtained whose eigenvalues are purely imaginary corresponding to the decay rate of the temperature field. Our work paves the way for the investigation of how periodicity alters topological states in thermal diffusion systems, potentially revolutionizing the design of thermal metamaterials for topological thermal protection in thermal management.

Ground state of one-dimensional fermion-phonon systems

Ground state of one-dimensional fermion-phonon systems

Simultaneous state and fault estimation for a class of nonlinear Markov jump systems by distributed fault-tolerant observers

This paper investigates the estimation problem of a class of nonlinear Markov jump systems with actuator and sensor faults. The main goal is to design a distributed fault-tolerant observer to estimate system states and actuator faults simultaneously. Firstly, a novel distributed observer network is constructed to compensate the missing information of unobservable nodes of the system. Next, a class of new redundant sensors are set up on each distributed observer node to obtain more output measurement samples. More importantly, when some of the mentioned sensors occur faults, an index of sensor heath level is constructed to characterize the quality of the faulty sensor information. Further, a novel algorithm is designed to mask low quality output information and filter out relatively healthy one automatically. Based on the selected healthy output information, the system state and actuator fault are estimated in the case of sensor failure. Finally, an example is provided to demonstrate the effectiveness of the proposed method.

Recent progress of JT-60SA project toward plasma operation

Abstract Superconducting tokamak JT-60SA plays an essential role in fusion research and development by supporting and complementing ITER project, providing directions to the DEMO design activity and fostering next generation scientists and engineers. Since the incident of the Equilibrium Field coil #1 during the Integrated Commissioning (IC) in March 2021, both EU and JA Implementing agencies (IAs) have examined how to ensure safety operation of JT-60SA by mitigating the risk of possible discharge occurrence inside the cryostat. Based on the experience of the Global Paschen tests, the IAs have established a strategy of risk mitigation measures, which is a combination of (i) reinforcement of insulation, (ii) avoiding unnecessary voltage application to the coil systems and (iii) immediate de-energization of the coils when deteriorated vacuum condition is detected. Thanks to the considerable efforts of the Integrated Project Team (IPT) members, the IC restarted in May 2023. After the confirmation of superconducting state of coil systems (TF, EF and CS), the coil energization test and the plasma operation (OP-1) starts. The first plasma was successfully achieved on 23 October 2023 with a limited value of applied voltage and current to the coils. The plasma configuration control will be also confirmed with low plasma current and low auxiliary heating power conditions. Based on the IO-F4E-QST collaboration, activities of JT-60SA have been shared with the IO and provided an important lesson learned for ITER assembly and commissioning, and will provide an outstanding contribution to fusion research at large. After OP-1, Maintenance & Enhancement phase 1 (M/E-1) starts from January 2024, in which in-vessel components are installed, and heating system and diagnostic system are extensively upgraded to allow high power heating experiment planned in OP-2. In order to make the best use of JT-60SA, newly organized JT-60SA experiment team will refine the research plan in the future high heating power operation phase.

Clifford orbits and stabilizer states

Abstract Stabilizer states serve as “classical objects” in the stabilizer formalism of quantum theory, and play an important role in quantum error correction, fault-tolerant quantum computation, and quantum communication. They provide an efficient description of many basic features of quantum theory and exhibit a rich structure. For prime dimensional systems, they may be defined by two quite different yet equivalent ways: The first is via stabilizer groups (maximal Abelian subgroups of the discrete Heisenberg-Weyl group). The second is via the orbits of the Clifford group acting on any computational basis state. However, in a general dimensional system, this equivalence breaks down, and consequently, it is desirable to classify the difference and relation between the above two approaches to stabilizer states. In this work, we show that these two approaches are equivalent if and only if the system dimension is square-free (i.e., has no square factor). Furthermore, we completely clarify the relation between the Clifford orbits and stabilizer states in an arbitrary dimensional system, derive the explicit expressions of the Clifford orbits and determine their cardinalities.

Long-term consequences of the functional state of the respiratory system after SARS-CoV-2-associated lung damage

Aim. To study the dynamics of respiratory system function in patients without a history of bronchopulmonary pathology after SARS-CoV-2 infection with virus-associated lung damage.Materials and methods. A retrospective study was conducted on 29 patients (median age 46 [43-51] years) at two stages: visit 1 (1-4 months) and visit 2 (8-13 months) from the onset of COVID-19. Data from spirometry, bodyplethysmography, diffusion capacity test, impulse oscillometry (IOS), and chest computed tomography (CT) obtained during the acute phase of the disease (CTmax), as well as dyspnea assessed by the mMRC scale, were analyzed.Results. The median CTmax was 75%, and 66% of patients received treatment in the intensive care unit. At visit 1, dyspnea was of mild or moderate severity. Medians of vital capacity (VC), total lung capacity (TLC), residual volume (RV), and diffusion capacity of the lungs (DLco) were reduced (<80% predicted). The median forced expiratory volume in the first second (FEV1) and IOS parameters were within normal ranges. However, increased reactance area (AX) and absolute frequency dependence of resistance (R5–R20) were found in 59% and 24% of cases, respectively. At visit 2, mild dyspnea persisted. Lung volumes were within normal limits, with statistically significant differences between visits. The median DLco was reduced at visit 1 but increased to normal at visit 2, with statistically significant differences between visits. The median IOS parameters remained within normal limits, with no statistically significant differences between visits. However, in visit 1 increased AX and (R5–R20) were observed in 59% and 24%, in visit 2 – 45% and 17% of cases, respectively, with no statistically significant differences between visits.Conclusions. Among the long-term functional consequences of SARS-CoV-2 infection with virus-associated lung damage, decreased lung diffusion capacity (reduced DLco) and small airway dysfunction (increased AX and/or R5-R20) were noted in some patients. Impulse oscillometry should be included in the comprehensive functional assessment plan for patients after SARS-CoV-2 infection to diagnose small airway dysfunction.

The functional state of athletes who have undergone coronavirus infection (COVID-19)

This study aimed to investigate the energy supply of athletes, who had a mild form of coronavirus infection (COVID-19) under cycling ergometric load (CEL) to substantiate the timing of recovery, as well as to determine the volume and intensity of physical activity. Eighty-seven athletes aged from 18 to 28 years old, involved in cyclic sports, were examined. Group I consisted of 52 athletes with COVID-19, and group II consisted of 37 healthy self-isolating athletes. In addition to the comprehensive examination, the tested athletes underwent special examinations: the study of diagnostic material using methods of nucleic acid amplification, spirography and spiroergometry, electrocardiography (ECG), and CEL. The results of athletes from both groups did not differ significantly (p ​> ​0.5) in the 1st, 2nd, and 3rd examinations. The second examination revealed a discrepancy between functional reserves and the load performed, as evidenced by the difference in the recovery rate of most indicators, the results of the third examination in the long-term period (6 months) showed that the athletes of the first group did not have any violations of the parameters of the respiratory function (RF) and cardiovascular system at rest, after performing CEL, as well as in the recovery period. The results suggest that the full resumption of training loads and participation in competitions are possible only with the complete normalization of the functional state of the cardiorespiratory system. The most informative indicators are: minute ventilation (V˙E), heart rate (HR), oxygen pulse (OP), and coefficient of oxygen utilization (COU).

Physical model learning based false data injection attack on power system state estimation

The cyber security of power system state estimation (PSSE) is crucial, and its robustness against evolving false data injection attacks (FDIA) is being rigorously assessed to develop advanced countermeasures. Existing FDIA methods have achieved satisfactory success rates but often fail to align with practical constraints such as the assumption of partial or complete knowledge of the power system network by the attacker, modifications in generator output measurements, and the sparsity of the attacks. This work proposes a near practical, stealthy approach using a deep generative adversarial network-long short-term memory autoencoder (GAN-LSTMAE) learning based sparse FDIA method against AC PSSE, leveraging only measurement data. To evade the bad data detection (BDD) mechanism effectively, an LSTMAE-based PSSE mimic is proposed, further optimizing the GAN-based attack generator to embed the physical laws of the system along with measurement residuals and temporal dependencies of states to the generated false data. The proposed modified training data preparation algorithm, coupled with the attack sub-graph method, defines the optimal attack region while keeping generator output measurements intact. The generated attack is validated extensively using IEEE 14 and 118 bus test benchmarks against various defense techniques, demonstrating high success rates.

A novel second-order predictive disturbance observer for systems with input and output delays

This paper proposes a novel second-order predictive disturbance observer for systems experiencing external disturbance with both input and output measurement delays. The proposed observer uses the delayed system state and its derivative information to predict and compensate for future disturbance in real time, despite the delayed control input. Compared with the past studies about second-order disturbance observer, this paper analyses the impact of the disturbance derivatives on the estimation accuracy. This observer is designed using the Lyapunov–Razumikhin theorem and its exponential stability is proven. Comparative analysis and simulations demonstrate its advantages over second-order disturbance observers that do not consider delays.

Disturbance rejection for switched singular systems using state decomposition technique and equivalent-input-disturbance with a dynamic state observer

In this study, an equivalent-input-disturbance (EID) method with a dynamic state observer and a state decomposition technique (SDT) are used to explore the disturbance rejection of a class of linear switched singular systems. The EID approach defines an EID signal, is defined for the control input channel and has the same impact on the system as exogenous disturbances. Additionally, it employs an observer to estimate the EID and achieves good disturbance-rejection performance. However, in the EID method, the coefficient matrix of the observer needs to be consistent with the coefficient matrix of the original system, which limits the application of the method. So, a dynamic state observer is designed to reconstruct the system state and estimate the disturbance in this study. Based on the state feedback control strategy, a disturbance-rejection control law containing disturbance information is designed and a closed-loop control system structure is established. Subsequently, the state equation of the closed-loop system is reorganized and decomposed into an algebraic equation and a differential equation using the SDT. Then, a Lyapunov function with few decision variables is designed to obtain an admissible criterion for the closed-loop system and the controller gains under arbitrary switching signals. Finally, the effectiveness of the presented method is verified via numerical simulations.

CoOMBE: A suite of open-source programs for the integration of the optical Bloch equations and Maxwell-Bloch equations

The programs described in this article and distributed with it aim (1) at integrating the optical Bloch equations governing the time evolution of the density matrix representing the quantum state of an atomic system driven by laser or microwave fields, and (2) at integrating the 1D Maxwell-Bloch equations for one or two laser fields co-propagating in an atomic vapour. The rotating wave approximation is assumed. These programs can also be used for more general quantum dynamical systems governed by the Lindblad master equation. They are written in Fortran 90; however, their use does not require any knowledge of Fortran programming. Methods for solving the optical Bloch equations in the rate equations limit, for calculating the steady-state density matrix and for formulating the optical Bloch equations in the weak probe approximation are also described. Program summaryProgram Title: CoOMBECPC Library link to program files:https://doi.org/10.17632/5wsg9d52dk.1Developers' repository link:https://github.com/durham-qlm/CoOMBELicensing provisions: GPLv3Programming language: Fortran 90Nature of problem: The present programs can be used for the following operations: (1) Integrating the optical-Bloch equations within the rotating wave approximation for a multi-state atomic system. At the choice of the user, the calculation will return either the time-dependent density matrix at given times or the density matrix in the long time limit if the system evolves into a steady state in that limit. The calculation can be done with or without averaging over the thermal velocity distribution of the atoms. The number of atomic states which can be included in the calculation is limited only by the CPU time available and possibly by memory requirements. An arbitrarily large number of laser or microwave fields can be included in the calculation if these fields are all CW. This number is currently limited to one or two for fields that are not all CW. The calculation can be done in the weak probe approximation, or in the rate equations approximation, or without assuming either of these two approximations. Calculating refractive indexes, absorption coefficients and complex susceptibilities is also possible. (2) Integrating the 1D Maxwell-Bloch equations in the slowly varying envelope approximation for one or two fields co-propagating in a single-species atomic vapour. Although geared towards the case of atoms interacting with laser fields, this code can also be used for more general quantum systems with similar equations of motion (e.g., molecular systems, spin systems, etc.).Solution method: The Lindblad master equation is expressed as a system of homogeneous first order linear differential equations, which are transformed as required and solved to obtain the density matrix representing the state of the atomic system. A variety of methods are offered to this end. The same approach is also used in the calculation of the polarisation of the medium when integrating the Maxwell-Bloch equations. The latter are integrated over space using predictor-corrector methods. The library includes a general driving program making it possible to use these codes without additional program development. The distribution also includes examples of the use of a container for running these programs without a pre-installed Fortran compiler.

USE OF IIoT TECHNOLOGIES IN ENGINE MONITORING AND CONTROL SYSTEMS

Determining the operating parameters of engine systems is very important to ensure its long-term reliability. Modern power plants use a large number of modern electronic components (sensors, controllers, etc.). All systems generate a huge volume of data that must be tracked, processed and analyzed, which in turn creates calls to gateways and servers. However, the current state of development of microcontrollers and their power allow the use of fog computing, which can lead to more efficient use of both the power plant and data transmission systems. Also, the use of modern microcontrollers and fog computing allows modernizing old power plants with minimal effort and creating new information nodes for monitoring the state of nodes and engine systems and easily combining them with systems already existing on the engine. The selection of a microcontroller and justification of its type for the modernization of the fuel system of a diesel engine are considered. Rapid processes occur in the high-pressure fuel system of diesel engines, which can be determined by changes in fuel pressure. For detailed measurement of processes in the fuel system, measurements should be made with a frequency of at least 24 kHz, i.e.: if the crankshaft rotation frequency is 4000 min-1, then 24,000 measurements should be made every second (when registering data after 1 degree of crankshaft rotation). Another indicator that imposes its requirements is the bit rate of the analog-to-digital converter (ADC), which depends on the range of recorded values. For example, an ADC with a resolution of 8 bits is capable of outputting 256 discrete values (0…255). That is, the higher the bit rate, the more sensitive the converter is to signal changes, and 8 bits may not be enough. Thus, even a small number of sensors can generate a huge amount of data. Transmitting large amounts of data is irrational and can lead to data loss and "clogging" of transmission channels, which challenges the computational performance of the microprocessor.

Investigation of an Ancient Wooden Cantilever Covered Bridge in China: Construction Form and Mechanical Properties

Wooden cantilever-covered bridges are typical Chinese constructions due to their structural style and architectural decoration. Yanzi bridge, an ancient wooden cantilever-covered bridge with more than 220 years of history in Anhua, China, has attracted increasing attention in recent years. In this study, its construction form and cultural background were investigated, and the structural components, original materials and mechanical behavior of the bridge were investigated in detail. First, the same type of raw material used for the Yanzi bridge, namely, pinus koraiensis, was tested to better understand its mechanical properties. Then, a finite element model was built to simulate the mechanical behavior of the bridge, and the stress state and internal forces of the cantilever system were obtained. According to the numerical results, when the loads are transferred downward and evened by the beams in the same layers of the cantilevers, the maximum deflection of the bridge of 12.8 mm meets the requirements of not exceeding L/600 in the specification, and the maximum normal stress of 1.35 MPa is much less than the ultimate tensile strength of the wood. This indicates that the structural safety performance of the ancient wooden cantilever-covered bridge is acceptable. Finally, a small amount of tiny damage of the bridge was observed and presented in the paper. This damage is not severe enough to cause brittle collapse, but care and maintenance are necessary to preserve this old historical bridge.