Normal Operation Of System Research Articles

A Dynamic Reconfiguration Scheme for Embedded System Based on Multi-core DSP

High-performance embedded system is needed in high-speed and accurate avionics control systems, but its hardware resources are limited. It is of great significance to reuse hardware resource through static or dynamic reconfiguration. A dynamic local reconfiguration scheme is designed based on c6678 isomorphic multi-core DSP to realize the dynamic reconfiguration of software on a single core under the premise of ensuring the normal operation of the whole system. This reconfiguration scheme can realize the complete switching of software on the whole core and realize the time division multiplexing of multiple algorithms in the same memory space. Experimental results show that the scheme can fully meet the requirements of real-time.

UKF-Based State Estimation for Electrolytic Oxygen Generation System of Space Station

Electrolytic oxygen generation system (EOGS) is the only system that can provide oxygen for astronauts in a physicochemical regenerative way in a long-term manned spacecraft. In order to ensure that the astronauts in the cabin can obtain a continuous and enough oxygen supply, it is necessary to carry out real-time condition monitoring and fault diagnosis of the EOGS. This paper deals with condition monitoring and fault diagnosis of the EOGS. Firstly, the dynamic model of the system is established based on the principle electrolysis for actual oxygen production system and the state observer of the system has been designed by using unscented Kalman filter (UKF). The total pressure in the cabin and the partial pressure of oxygen in the electrolytic cell can be observed. Then, considered the actual conditions of the manned space mission with one more astronaut, i.e., 3 astronauts, the simulation experiment is carried out. The simulation results show that the method can effectively estimate the system state, and it is of great significance to ensure the normal operation of the electrolytic EOGS system in the space station.

Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis.

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

Life Prediction of Battery Using a Neural Gaussian Process with Early Discharge Characteristics.

The state of health (SOH) prediction of lithium-ion batteries (LIBs) is of crucial importance for the normal operation of the battery system. In this paper, a new method for cycle life and full life cycle capacity prediction is proposed, which combines the early discharge characteristics with the neural Gaussian process (NGP) model. The cycle data sets of commercial LiFePO4(LFP)/graphite cells generated under different operating conditions are analyzed, and the power characteristic P is extracted from the voltage and current curves of the early cycles. A Pearson correlation analysis shows that there is a strong correlation between P and cycle life. Our model achieves 8.8% test error for predicting cycle life using degradation data for the 20th to 110th cycles. Based on the predicted cycle life, capacity degradation curves for the whole life cycle of the cells are predicted. In addition, the NGP method, combined with power characteristics, is compared with other classical methods for predicting the remaining useful life (RUL) of LIBs. The results demonstrate that the proposed prediction method of cycle life and capacity has better battery life and capacity prediction. This work highlights the use of early discharge characteristics to predict battery performance, and shows the application prospect in accelerating the development of electrode materials and optimizing battery management systems (BMS).

Research on Hybrid Index Method of Double-Layer B+ Tree for Power Big Data Considering Knowledge Graph

Efficient power data access can not only ensure the normal operation of power system, but also be one of the key supporting technologies to improve the operational efficiency of power grid enterprises. Aiming at the problem that traditional B+ tree does not take into account the relevance of power information fragments and cannot be indexed flexibly, a hybrid index structure and index method of power big data with knowledge graph is proposed, that is, the first layer uses B+ tree structure to store attributes, and the second layer uses knowledge graph to store attribute value, thus realizing the relevance index of power data. The simulation results show that the hybrid index structure can achieve the index of power big data with relevance information without affecting the index efficiency, which provides technical reference for efficient retrieval of multi-modal data in the future.

Analysis of Computer Network Maintenance Strategy Based on Lan

With the continuous development of society, Internet technology has also been popularized in people’s daily life and work. With the popularization of Internet technology, the computer will be interfered by all kinds of external information in the daily work process, and a series of network faults will appear. It is necessary to strengthen the maintenance and management of regional network to reduce the probability of computer network failure and ensure the normal and safe operation of computer system. This paper analyzes the ways of strengthening LAN maintenance and reducing computer network failure.

Lifetime improvement for wind power generation system based on optimal effectiveness of thermal management

The power module plays a vital role in the renewable energy conversion. But it is one of the most prone to fail components in the wind energy system. The thermal management has been proved to be a cost-effective mean to improve the reliability of wind energy system, but it has a dual nature. To balance the benefit and risk of thermal management, a lifetime extension strategy is proposed. This strategy considers the minimum junction temperature fixed to the lowest ambient temperature and the allowed maximum junction temperature determined by the predefined temperature swing. Then the related wind speeds of predefined temperature swing can be concentrated in a part wind speed area and the effectiveness of thermal management under each predefined temperature swing is calculated. The optimal effectiveness is chosen as a quantitative evaluation criterion to design the working range of thermal management and control target of junction temperature in a long time scale. As a benefit, the economic performance of thermal management is greatly improved in that each application of temperature control can reduce as much consumed lifetime of power module as possible. Case studies and experiments are presented for performance verification of proposed strategy. Results show that the consumed lifetime reduced by each application of temperature control is 6.04 × 10-3%. The expected lifetime of power module is extended from 7.55 years to 22.08 years which meets the target lifetime of wind power generation system (20 years). In addition, this method only needs to be applied in the specified working range where the wind speed is higher than 9.30 m/s. Thus, the disturbance on the system's normal operation is significantly alleviated.

An Optimal Parameter Selection Method for MOMEDA Based on EHNR and Its Spectral Entropy.

As a vital component widely used in the industrial production field, rolling bearings work under complicated working conditions and are prone to failure, which will affect the normal operation of the whole mechanical system. Therefore, it is essential to conduct a health assessment of the rolling bearing. In recent years, Multipoint Optimal Minimum Entropy Deconvolution Adjusted (MOMEDA) is applied to the fault feature extraction for rolling bearings. However, the algorithm still has the following problems: (1) The selection of fault period T depends on prior knowledge. (2) The accuracy of signal denoising is affected by filter length L. To solve the limitations, an improved MOMEDA (IMOMEDA) method is proposed in this paper. Firstly, the envelope harmonic-to-noise ratio (EHNR) spectrum is adopted to estimate the fault period of MOMEDA. Then, the improved grid search method with EHNR spectral entropy as the objective function is constructed to calculate the optimal filter length used in the MOMEDA. Finally, a feature extraction method based on the improved MOMEDA (IMOMEDA) and Teager-Kaiser energy operator (TKEO) is applied in the field of rolling bearing fault diagnosis. The effectiveness and generalization performance of the proposed method is verified through comparison experiment with three data sets.

Fault Propagation Inference Based on a Graph Neural Network for Steam Turbine Systems

A fault propagates along physical paths until it reaches the boundary of the equipment or system, which shows as a functional failure. Hence, inferring the fault propagation helps to ensure the normal operation of the industrial system. To infer the fault propagation in the steam turbine system, a graph model is developed. Firstly, a process graph topology is constructed according to the system mechanism, whose nodes and edges represent the equipment and mutual relationships. Meanwhile, a fault graph topology is built, in which nodes indicate potential faults and edges are inferred propagation paths. Then, the representations of fault nodes are realized through a graph neural network. Lastly, link prediction methods based on nodes’ representations are conducted, along with the paths inference results. Consequently, the accuracy of fault propagation inference for the steam turbine system is over 86%.

Krivičnopravni izazovi u Republici Srbiji za vreme pandemije COVID-19

The pandemic caused by the spread of the infectious disease COVID-19, which affected the entire planet, caused not only the global health crisis, changing the usual way of life of the majority of the world's population, but also affected almost all areas of the state and social system. The health systems were most affected; however, in addition to them, the effects of measures adopted by national legislators or other competent authorities to eliminate or reduce the risk of spreading the disease have affected, inter alia, economic stability, but also challenged the judicial authorities given that in the new circumstances it was not easy to ensure their normal functioning. This primarily refers to the criminal justice, given the importance of cases and the need for urgent action, since it is necessary to ensure the conduct of trials and the work of all procedural entities in conditions that, at least in one period, implied drastic restrictions on some basic civil and human rights and freedoms. In that context, it is especially important to review the justification and legality of the measures introduced in the Republic of Serbia during the state of emergency with the aim of more or less normal operation of the judicial system in conditions when social life was almost completely paralyzed. In addition, there is the question of what challenges and controversial issues are generally posed before criminal law in a pandemic, as well as the analysis of data on the crime rate and the overall crime situation in the Republic of Serbia in the period since the introduction of the state of emergency and during the pandemic.

Research on switching loss reduction technology for missileborne DC-DC power supply

With the development of power electronics technology, DC-DC power supply is widely used in secondary power supply system on missile. How to restrain the loss caused by the periodical on-off of the switch tube plays an important role in ensuring the normal operation of the missile-borne power supply system. In this paper, the switching-tube Absorption Circuit and ZCT PWM soft-switching circuit are taken as the research objects, and the effects of the two circuits on the switching-tube loss suppression in the dual-pulse-width modulation mode are analysed, and a more effective method to reduce the switching loss of high frequency DC-DC power supply is obtained, it provides a reference for the further research of switching loss reduction technology in high frequency DC-DC power supply.

Research on the Applicability of Financial Management System Based on Computer Erp System

In the EPR environment, the financial management system has the characteristics of integrity, scientific decision-making, timeliness of information acquisition and comprehensive information service. However, in the actual financial management process, due to the neglect of practical research, the upgrade and promotion of ERP software are hindered. On the whole, the ERP system is single and the rights and responsibilities are not clear. In order to improve the ERP financial management system, in the process of system design, it is necessary to clarify the system design requirements, clarify the system architecture and clarify the system functions. The realization of the whole ERP financial management system, based on the system development environment and database design, must establish the management model according to the enterprise management practice, strengthen the enterprise training, ensure the safety of information management, clarify the responsibilities of various departments and ensure the normal operation of ERP financial management system.

Seismic vulnerability assessment of multi-storey subway station structure

The safety of underground structure under seismic load is an important basis of the normal operation of underground rail transit system. Structural seismic vulnerability assessment based on incremental dynamic analysis method can evaluate the probability of the structure exceeding a certain limit state under a specific seismic intensity in terms of probability. In this paper, the seismic vulnerability of a multi-storey subway station structure is evaluated using this method, and a two-dimensional finite element model of both soil and structure is established by finite element software ABAQUS. The vulnerability curve is obtained through incremental dynamic analysis and mathematical statistics. Based on this curve, the probabilities of the structure exceeding four seismic limit states are obtained under the design seismic intensity and the rarely occurred seismic intensity at 7 degree. Results show that this station may attain slight damage under design seismic intensity of 7 degree, and may attain life safety at the rarely occurred seismic intensity at 7 degree.

Review of the Research on Augmented Reality Maintenance Assistant System of Mechanical System

In order to ensure the normal operation of mechanical system and solve the problems of complex structure and insufficient cognition caused by mechanical system updating, the advantages of applying augmented reality technology in the field of fault diagnosis and maintenance are analyzed. Firstly, this paper summarizes the application of augmented reality technology for maintenance assistance cases at home and abroad, analyzes its industry characteristics and application advantages, then summarizes the key technologies of augmented reality, and finally prospects the development trend of the system application.

A Time Optimal Trajectory Planning Method for Double-Pendulum Crane Systems With Obstacle Avoidance

For a crane system, when the payload is too large to be seen as a mass point, or the hook mass cannot be directly ignored, it performs more like a double-pendulum crane system, instead of a single-pendulum crane system. Due to many factors, the working environment of the industrial crane system is complex. Obstacles sometimes appear in the movement path of the payload, which affects the normal operation of the crane system and may cause accidents like collisions. To handle this issue, we propose a time optimal trajectory planning method for the double-pendulum crane system with obstacle avoidance, which ensures the objective of obstacle avoidance by the payload hoisting/lowering. During the trajectory planning process, a series of physical constraints, including the trolley velocity constraints, the trolley acceleration constraints, the payload’s swing angle constraints and the hook’s swing angle constraints are considered. It can improve the safety of the crane system during the entire working process and the transportation efficiency is also improved at the same time. Finally, the effectiveness of the proposed method is verified by simulations.

Design and Health Evaluation of Monitoring Test Platform for Metro Traction Power Supply System

Subway traction power supply system is the energy source of subway operation. The normal operation of subway traction power supply system is directly related to the stable operation and safety of subway. If the subway traction power supply system breaks down, it not only will cause economic losses, but also may cause social disorder. Therefore, it is of great significance to study the traction power supply system of subway to ensure the safe operation of subway. The establishment of a reasonable monitoring and testing platform, the simulation analysis of the traction power supply system, and the regular health assessment can provide a strong guarantee for the safe operation of the subway. This paper aims to design a practical test platform through MATLAB modeling, so as to establish a simulation model of subway traction power supply system, and comprehensively monitor and grasp the health status of subway traction power supply system. This paper quantitatively evaluates the health status of subway traction power supply system, applies the principle of multilayer immunity, establishes the traction power supply system of analytic hierarchy process (AHP), and constructs the immune monitoring system of each layer. This method can provide the health status information of subway traction power supply system, subsystems, and components comprehensively, accurately, and intuitively and determine the subsystems and components that need to be maintained.

Adaptive Background Compensation of Frequency Interleaved DACs With Application to Coherent Optical Transceivers

Digital-to-analog converters (DACs) with bandwidths larger than 70 GHz and sampling rates in excess of 170 GS/s will soon be required in ultra-high speed communication applications such as coherent optical transceivers operating at symbol rates of 140 GBd and beyond. Frequency interleaving has been proposed as a way to break the bandwidth bottleneck in such applications. Splitting the input signal into multiple frequency bands reduces the required bandwidth per interleaved DAC and therefore it enables the synthesis of greater bandwidth signals in the reconstructed output. Elaborate digital signal processing (DSP) is required to seamlessly stitch together the sub-bands and compensate the errors of the analog signal path, which would otherwise severely degrade the performance of the communication system. Adaptive DSP techniques are required to automatically compensate errors caused by process, voltage, and temperature variations in the technology (e.g., CMOS, SiGe, etc.) implementations of the data converters, and therefore ensure high manufacturing yield. These techniques must operate in background mode to avoid interfering with the normal operation of the communication system. This work introduces an adaptive background compensation scheme for frequency interleaved DACs (FI-DACs). The primary application example is a 128 GBd QAM16 coherent optical transceiver. However, the technique is applicable to other types of communication transceivers, and it can be generalized to arbitrary signals, as long as they are stationary or quasi-stationary and have a wideband continuous spectrum. The key elements of the proposed technique are a MIMO equalizer and the backpropagation algorithm. Numerical simulation results for the aforementioned application example show that the signal to noise and distortion ratio (SNDR) of the FI-DAC is boosted by more than 25 dB when the proposed compensation technique is applied in the presence of typical analog mismatches. Furthermore, the optical signal to noise ratio penalty of the optical transceiver is reduced from 6 dB to 0.1 dB.

Deep deformations of the upper stream of a low-pressure reservoir

The article presents the results of the analysis of the deep deformations of the Amu Darya riverbed in the upper reaches of the low-pressure reservoir. The analysis of the combined transverse profiles of the riverbed in different sections of the upper reaches of the Takhiatash reservoir showed that the coastal zones are most intensively silted up. At the same time, the core zone with the highest flow rates is very weakly declared. The height of the silting layer along the length of the upper stream increases in the direction of the dam. The silting area extends upstream for a length 2-3 times longer than the length of the soundings section, which is 17.5 km. To ensure the normal operation of the hydraulic system, it is recommended that conditions should be created for a normal and stable approach of the flow to the hydraulic system, which should be ensured by maneuvering the shield holes. To do this, it is necessary to create conditions for the erosion of the left-bank spillway by increasing the water flow through the extreme left-bank discharge holes. Flushing of the upper left-bank section of the river should continue until the optimal width of the leading channel is reached, which provides the main flow of the stream in front of the structure. It is proved that the formation and development of sediment deposits on the right bank between sections 8-10 leads to a change in the flow correction and creates conditions for the formation of shoals in front of the regulator of the Kizketken channel, which can complicate the operation of the water intake zone. Therefore, it is necessary to take measures to prevent the development of the right-bank channel, and the development of the channel should go from the main channel. As shown by monitoring operating mode Takhiatash waterworks, in the Takhiatash district waterworks intensive processes the channel formation, which has a strong influence on the operational mode of the dam, especially in the operation of the water intakes flushing of sediments, skip flood costs through the shields of the dam and the stability of structures.

Application of Mathematical Economic Model in Financial System in Manufacturing Industry

In the field of economic research, most of the sample data is not obtained based on controllable experiments but generated during the normal operation of the economic system. Therefore, the change of an economic variable is usually not caused by a single change of a cause variable. It is the result of a combination of multiple factors. Therefore, it is necessary to study the application of mathematical intelligent computing in computer intelligent manufacturing system. The purpose of this paper is to explore the application of mathematical intelligent computing in computer intelligent manufacturing system. For this reason, this paper uses the furnace temperature control model to carry out simulation experiment. In this simulation experiment, three algorithms of mathematical intelligent computing are mainly used, including BPES intelligent computing method, genetic algorithm, and MARS algorithm. The research results show that the superparameter optimization based on MARS has high efficiency, and the best result, the worst result, the average result, the variance, and the average time of multiple independent runs are controlled below 0.03 s. In this experiment, when the hidden layer node is 9, the prediction error value is the smallest, and the model simulation curve is basically consistent with the measured curve trend. In the simulation experiment of this paper, these three algorithms have shown good results in their respective links.

General Classification and Comprehensive Performance Assessment of Multi-Objective DC Voltage Control in Multi-Terminal HVDC Networks

The recent massive global movement towards green energy in power systems has raised the efforts of integrating large-scale Renewable Energy Sources (RESs) through Multi-Terminal HVDC (MTDC) systems. The configuration of the MTDC system and the possibility of transnational interconnection impose some challenges and raise the potential of single or multi-objective control for the DC voltage control. Additional requirements from the Transmission System Operator (TSO) and/or AC grids may influence the action taken for the DC voltage control. In this paper, a generalized classification for the DC voltage control methods in an MTDC system is delivered. The DC voltage control methods are classified into conventional control (i.e., reference voltage-based control) and non-conventional control (i.e., virtual resistance-based control) methods. The DC voltage control objective may cover a range of the following targets: power-sharing based on converters' rating capacity, ratio priority of the power distribution, available headroom, and/or loading factor. The control objective may include transmission losses minimization of the MTDC system with optimal or sub-optimal power flow. The design approaches of the control methods for post-contingency operation are presented. The control methods are evaluated and simulated with a 4-terminal radial MTDC network during normal and abnormal system operation. A comprehensive performance assessment is also presented considering the control methods from the perspective of the control method and objective, system efficiency, grid-code violation, communication requirement, and design complexity and flexibility.