Normal Operation Research Articles

Design and Application of Virtual Cloud OMS Computing in Smart Airport

Airport management takes airport information management as its key link, and it is also the key to ensure the safe operation of airports. As a modern information management and processing technology, cloud computing plays an indispensable role in the fields of efficient information processing, strengthening management and improving work efficiency. Under the development background of the information age, the management mode of airport operation and maintenance has also changed to some extent. In the growth of the new era, airport operation and maintenance managers need to introduce new technologies and then combine more advanced technologies with the airport operation and maintenance system (OMS) so as to promote the normal operation of the airport OMS based on advanced data acquisition, analysis, and integration technologies. This article studies the application of cloud computing technology and designs a virtual cloud OMS based on deep learning (DL) from the perspective of the security requirements of the management information system (MIS) to realize the fault diagnosis and identification of the airport MIS. The fault diagnosis technology of the airport MIS based on virtual cloud OMS and DL proposed in this study has broad prospects in practical application. It can be applied to airport operation and maintenance management, security, and other links, providing intelligent support for airport operation.

Application of Adaptive Fuzzy Algorithm in Single-Chip Microcomputer Control System

Objective: In practical application, an SCM control system needs to respond to user instructions quickly and accurately, and at the same time needs to have robustness and adaptability to adapt to complex and changeable environments and working states. Therefore, how to improve the control accuracy and stability of SCM control systems, and how to adapt to the change of different working environments and working states, has become one of the important issues in the design and research of SCM control systems. Methods: Adaptive fuzzy algorithm, as a new control algorithm, has the advantages of simple structure, easy implementation and high precision, and has been widely used in many fields. On the basis of three kinds of fuzzy logic system framework, this paper analyzes the self-adaptive fuzzy algorithm single-chip microcomputer control system and carries on the corresponding performance test of the system by constructing an intelligent car. The testability test of single-chip microcomputer detection, hardware detection, algorithm recognition rate and system control rate is tested, respectively, to ensure the normal operation of the system. Conclusion: The microcontroller control system of fuzzy algorithm system is compared with that of traditional algorithm system in many aspects. The average error rate of the traditional algorithm system is 2%, while the average error rate of the fuzzy algorithm system is 0.8%. In other aspects, the fuzzy algorithm system is superior to the traditional system. For example, the fuzzy algorithm system has a 100% instruction recognition rate and a data processing speed of up to 1 second. According to the characteristics and requirements of the single-chip microcomputer control system, applying the adaptive fuzzy algorithm to the design of a single-chip microcomputer control system can effectively improve the control precision and stability of thesystem.

Dynamic Analysis of the De-Ballasting Operations of a Floating Dock with a Malfunctioning Pump

AbstractDuring normal de-ballasting operations for floating docks, each ballast pump independently manages a specific group of ballast tanks. However, when a pump malfunctions, a connection valve between the two groups of ballast water systems is opened. This allows the adjacent pump to serve as a helper pump, simultaneously controlling two groups of ballast water systems. This study explores a full-scale floating dock’s dynamic behaviours during the de-ballasting operations under this situation through a numerical model. In the developed numerical model, the dock is described as a six-degree-of-freedom rigid body which is subjected to hydrostatic, hydrodynamic, and mooring loads. A hydraulic model of the piping network of the malfunctioning pump and the helper pump is proposed. A modified P-controller regulates opening angles of all tank valves for minimal pitch and roll. Two configurations of the floating dock, i. e., a single floating dock and a floating dock with an onboard vessel, are considered. The numerical results show that the optimal helper pumps can be identified regarding the pumps’ total de-ballasting capacity and the dock’s stability. The most severe scenarios can be determined in term of the dock’s maximum draught differences caused by its roll and pitch. The observed maximum draught differences remain small relative to the dock’s width, indicating the effectiveness of employing helper pumps and the proposed automatic ballast control strategy for one-pump malfunction scenarios.

Whole-process analysis and implementation of a self-powered wireless health monitoring system for railway bridges: Theory, simulation and experiment

In this work, a self-powered wireless health monitoring system (SP-WHMS) combined with the Internet-of-Things (IoT) is proposed and implemented for a long-term and long-distance health monitoring of railway bridges. This system frees the wireless sensor nodes (WSNs) from their dependence on chemical batteries by using the piezoelectric energy harvester (PEH) to harvest the vibration energy from bridges to power the WSNs. The whole-process of the SP-WHMS including energy conversion, energy storage, energy management and application is analyzed at the first time through theory, simulation and experiment. For the energy conversion, a reported PEH model with high energy conversion efficiency (called D-M PEH) is refabricated, which can achieve a maximum average output power of 0.9 W under unit harmonic acceleration excitation. For the energy storage, a high-precision iteration analysis procedure (IAP) is proposed to predict the charging process of the strong-coupled PEHs and the charging process under non-harmonic excitations. The comparison results show that the IAP’s prediction deviates less than 3% from the experiment result and even less than 1% from the simulation result. For the energy management, an AP64500 chip with two adjustable input voltage thresholds and a stable output voltage ensures the normal operation of the SP-WHMS and makes the SP-WHMS suitable for different types of WSNs. For the application, the synergies between energy conversion, storage and management are considered, and the effectiveness of the SP-WHMS used on railway bridges is tested through an activation experiment. This work provides a technical guidance and framework for the implementation of the self-powered wireless monitoring on railway bridges.

Analysis of problems and countermeasures in computer network engineering security

This paper analyzes the existing security issues in computer network engineering and proposes a series of countermeasures. To address the problems of hacker attacks and information leakage, it is recommended to strengthen network monitoring and the application of encryption technology. For the issues of malware and virus dissemination, it is advised to regularly update antivirus software and enhance employee security awareness training. Regarding network data leakage and privacy breaches, the use of secure transmission protocols and multi-factor authentication technology is advocated. For network security management and maintenance issues, establishing a sound security management system and emergency response plans is recommended to ensure the stable operation of network systems. Through the implementation of the above measures, the security level of computer network engineering can be effectively improved, ensuring the normal operation of network systems and the security of information.

Silent Neonatal Incubators, Prototype Nica+

Objectives: The purpose of this study was to evaluate and compare the noise levels in current incubator models and a prototype designed to improve acoustic comfort in neonatal incubators. Methods: Tests were carried out on three different models of incubators and a prototype called Neonatal Incubator Acoustic Comfort Class (NICA). The tests measured both internal and external sound pressure levels under laboratory conditions. The noise index has been taken as the A-weighted equivalent continuous sound pressure level (LAeq,T) for a time interval of 1 min. Results: The results obtained show variations between the different models of incubators, although, overall, they are high values (around 56/60 dBA). The results prove that premature newborns under normal conditions of using these incubators are exposed to noise levels above international recommendations. The new incubator design minimizes noise generation and generates noise levels lower than international recommendations. Conclusions: The results obtained from the prototype (NICA+) show the effectiveness of the proposed design in improving acoustic comfort in neonatal incubators. The data show that the noise levels generated by the prototype under normal operating conditions are significantly lower than international recommendations.

Geospatial analysis of scour development post-protection in offshore wind farm

Scour is one of the most serious challenges affecting the normal operation of offshore wind power. Whether scour protection measures are effective directly affects the safety and economical efficiency of an offshore wind farm. Data mining techniques and analytical tools based on monitoring data analysis plays a critical role in making appropriate strategic decisions. Post-protection scour inspection was continuously carried out on a typical offshore wind farm composed of 72 turbines installed with monopile foundations for three times over the course of two years. The geospatial properties of scour, including maximum scour depth, maximum scour extension, and scouring and siltation volume, were analyzed in detail. The possible autocorrelation of scour data measured for each turbine was identified using data-driven decision-making process. The results indicate that the characteristics of the investigated scour and their spatial dependence on the turbines of the inspected offshore wind farm generally show an upward trend over time. A High-High area in the local geospatial dependency map of maximum scour depth was identified, and an equation was drawn for predicting development of maximum scour depth. These findings show indications to reduce the operation and maintenance costs of offshore wind farms and improve the efficiency for upgrading scour protection on specific offshore wind foundations.

Research on the Shareholder Delisting System of Limited Liability Companies

Limited liability companies have become an indispensable part of the market economy due to their advantages in combining talent and capital, while continuously attracting more investors to participate. However, there are also some shareholders who intentionally fail to comply with the agreement and are unwilling to fulfill their capital contribution responsibilities. In this case, the shareholder delisting system has emerged. This system refers to the mandatory cancellation of the shareholder status of expelled shareholders in accordance with the company's articles of association or resolutions of the shareholders' meeting, in order to resolve internal disputes within the company, avoid escalating conflicts among shareholders, and ensure the normal operation of the company. At present, the shareholder delisting system in China still faces problems such as incomplete scope of reasons, lack of operability in procedures, and inability to protect the rights of relevant parties after shareholder delisting. Therefore, we need to improve the reasons and implementation procedures of the shareholder delisting system, as well as the relief measures for relevant parties after shareholder delisting.

Thermodynamic performances of a novel multi-mode solar-thermal-assisted liquid carbon dioxide energy storage system

Liquid carbon dioxide energy storage is an efficient and environmentally friendly emerging technology with significant potential for integration with renewable energy sources. However, the heat recovery and utilization during compression and expansion are not implemented well. This paper proposes a multi-mode solar-thermal-assisted liquid carbon dioxide energy storage system integrated with the organic Rankine cycle. Three operation modes of normal operation mode, heat distribution operation mode, and solar thermal power generation mode are developed to achieve flexible control of the system under both normal and extreme environmental conditions. Thermodynamic performance analysis of the system under normal operation mode shows that compared to traditional system with energy storage density of 8.55 kWh/m3, the overall efficiency of the coupled system increases from 49.5 % to 62.1 %, with an energy storage density reaching 21.74 kWh/m3. The impact of key parameters such as temperature and pressure on system performance is discussed. Furthermore, an analysis of the heat flow distribution ratio under the heat distribution mode was conducted, indicating optimal system performance at a heat flow ratio of 6:4. Comparative analysis of the system performance under various operating conditions for the three operation modes was performed, elucidating the operational strategies of each mode.

Machine learning-based digital twin of a conveyor belt for predictive maintenance

The problem of achieving a good maintenance plan is well-known in the modern industry. One of the most promising approaches is predictive maintenance, which schedules interventions based on predictions made by collecting and analyzing data from the process. However, to the best of the authors’ knowledge, this approach is still not widespread and known enough, and particularly, the real-case scenarios of its application appear not exhaustive. To contribute to fill this gap, this work proposes a digital twin (DT), which performs a predictive maintenance approach for a conveyor belt within a real-case scenario with the overall goal of predicting faults during normal belt operations. Specifically, the core of the implemented DT is a model that analyzes the data collected by various sensors distributed along the conveyor belt. In turn, this model exploits a machine learning-based algorithm that predicts the insurgence of faults. The tests of the developed solution, conducted within a real scenario, demonstrated good precision and accuracy in identifying the fault status and also in a time deemed acceptable for the involved stakeholders.

Thermal Model of the AGR-5/6/7 Experiment with Offset Gas Gaps

Because of their high impact on calculated temperatures, the offset gas gaps between the graphite holder and capsule wall are evaluated for the thermal model of the Advanced Gas Reactor 5/6/7 (AGR-5/6/7) irradiation experiment. Fuel compact temperatures are a crucial factor in assessing the irradiation performance of tristructural isotropic (TRISO)-coated-particle fuel for use in high-temperature gas-cooled reactors. TRISO fuel irradiation performance is a core tenet of the U.S. Department of Energy’s Advanced Gas Reactor Fuel Development and Qualification Program, conducted in the Advanced Test Reactor at Idaho National Laboratory. Specifically, the irradiation experiments were intended to provide irradiation performance data to support fuel process development, qualify fuel for normal operating conditions, support the development of fuel performance models and codes, and provide irradiated fuel and materials for postirradiation examination and safety testing. The thermal model used to predict the fuel compact temperatures was a three-dimensional finite element model that was subject to uncertainty. The most dominant factor in the uncertainty pertaining to calculated fuel temperatures is the gas gap uncertainty, which is caused by the graphite holder nub-to-capsule wall clearance. In AGR-5/6/7 capsules, the graphite holders can be shifted away from being perfectly centered inside the stainless steel capsule walls. This is due to irradiation-induced graphite shrinkage or to insufficient nubs on the graphite holder leading to azimuthally varying gas gaps during irradiation. A method was developed to find the best offset magnitude and direction at the top and bottom of the graphite holders in Capsules 1 and 2, which experienced higher temperatures than originally predicted among the five AGR-5/6/7 axially dispersed capsules irradiated between 2018 and 2020. The differences between the calculated and the measured temperatures of thermocouples (TCs) placed in the graphite holder near the fuel compacts were used as the basis for the holder offset determination. The best-fit offset assumes that the root-mean-square error between the measured and calculated TC temperatures is a minimum value. Typical offsets in the range of 0.002 to 0.004 in. increase the fuel compact temperatures in the range of 100°C to 200°C when compared to the zero offset for Capsules 1 and 2. Additionally, because of irradiation-induced changes in the capsule geometries, the holder offsets change throughout the irradiation period.

Stress Evaluation Using Finite Elements in a Manual Agricultural Tool

This study addresses the imperative need for efficient hand-held agricultural tools, particularly in challenging contexts like hillside agriculture, by focusing on the redesign and evaluation of a manual tillage tool. The objective is to comprehensively assess the stress and fatigue life of a redesigned tool, considering different manufacturing materials such as steels (AISI/SAE 4140, 4130, 1060), A356 aluminum, and nodular cast irons. Employing finite element method simulations and the Von Mises equation, this research confirms an optimal performance within elastic limits for all materials, mitigating the risks of plastic deformation or breakage during normal operation, with Von Mises stresses ranging from 8.39 to 16.30 MPa. All the tools yielded optimal results, meeting the critical requirements for soil penetration resistance, reporting no fatigue failures, and exhibiting useful life values over 1.75 x 1013 years. In terms of ergonomics, A356 aluminum stands out, as it is less heavy and implies a lower effort by the operator, promoting efficient tillage without compromising comfort. This research provides nuanced insights for the design of agricultural tools, emphasizing the harmonious balance between efficiency, longevity, and operator comfort in sustainable practices.

AC Micro Grid Fault Analysis

Implementation of micro grid concept creates several issues to the existing protection scheme in the radial distribution network. Depending on the location and capacity of the distributed generators, the short-circuit current from the main grid and distributed generations causes variations in the fault current levels inside the micro grid. The changes cause effect of sympathetic tripping, blinding of protection, relay over-reaching, relay under-reaching and loss of selectivity of the overcurrent protection scheme. Such issues must be managed carefully to ensure full benefit from micro grid adaptation. Conventional protection schemes are unable to detect fault current levels common in micro grid. Several methods have been proposed in various research paper. Micro grid protection is substantial to provide reliable and continuous power supply to the customers. The main aim of proposed work is to detect the fault for fast restoration of the system back to the normal operation. The proposed protection scheme for micro grid uses intelligent electronics device for detecting the fault

Exploring the effects of interdependencies on energy systems in smart communities: A multi-domain modeling and quasi-Monte Carlo sensitivity analysis

An efficient smart and connected community (SCC) depends on the interconnectivity of essential infrastructure systems. However, current modeling tools are unable to determine which interconnections are most important to include, particularly as system dynamics become more complex with high-order effects. To bridge this gap, we propose a comprehensive framework that incorporates multi-layers, multi-blocks, and multi-agents to model interdependent infrastructure systems. Interconnections span cyber, physical, and logical aspects, including human interactions. With the equation-based object-oriented language Modelica, we model energy, transportation, communication, and water systems for a hypothetical SCC and assess higher-order interdependency effects during normal operation. Additionally, we develop a quasi-Monte Carlo sensitivity analysis framework and use variance-based sensitivity metrics to assess the impact of interdependencies on energy system operation. Compared to the decoupled baseline system, the energy consumption of logical interdependency cases varied by 23.3%, the cyber interdependency by 2.0%, and the nested global interdependency by 21.5%. The sensitivity analysis further revealed that interrelationships are not linear nor quadratic, but involve higher-order interactions between parameters. Specifically, occupancy and cyber delays had significant first-order effects. Road delays had a significant higher-order effect, which corresponded to a stronger influence on other model parameters. By modeling higher-order cascading dependencies, our proposed framework has the potential to improve the planning, operation, and co-design of SCCs by quantifying the importance of complex system interactions.

Government Subsidies and IPO Firms’ Short-Term Excess Returns: Evidence from China

AbstractAs an important tool for local governments to intervene in the listing process in their jurisdiction, the implementation effect of government subsidy has been quite controversial. This study examines the pricing mechanism of Initial Public Offerings (IPO) within China’s macro institutional environment. The period from April 2012 to December 2015 was selected as the sample observation period, with companies listed on Growth Enterprise Market (GEM) as the study objects. By focusing on IPO firms’ short-term excess returns, the multiple linear regression model and propensity score matching method (PSM) were applied to evaluate the actual impact of local government intervention through financial subsidies during the listing process. The results show that government subsidies improve IPO firm’s short-term excess returns. This promotion effect is more significant in state-owned enterprises rather than in private enterprises. Moreover, the implicit window guidance weakens the promotion effect of government subsidies on the short-term excess returns. Further, the more government subsidies the IPO firms receive, the worse their long-term performance will be. The findings demonstrate that local governments employ financial subsidies to expedite the listing process within their jurisdiction, thereby facilitating IPO companies in generating short-term excessive returns while simultaneously impeding the normal production and operation. The conclusion enhances theoretical understanding regarding high underpricing, while also offering investors a novel approach to interpreting government subsidy information and assessing IPO firm’s earnings sustainability.

Control-oriented multiphysics model of a lithium-ion battery for thermal runaway estimation under operational and abuse conditions

This study proposes a control-oriented multiphysics model for lithium-ion batteries (LIBs) that can estimate electrochemical-thermal responses in real time under normal operation and abuse conditions. The proposed model integrates the simplified electrochemical model, the thermal resistance network, and the adaptive time-stepping method to ensure computational efficiency without sacrificing the accuracy. Specifically, the diffusion equation of the electrochemical model is simplified by addressing Padé approximation. The thermal resistance network estimates 3D temperature distribution through simple matrix multiplication to account for the entropic, ohmic, and chemical reaction during thermal runaway. The adaptive time-stepping method further secures accurate yet fast explicit calculation. Quantitative experimental validation reveals the high accuracy and robustness, and fast inference time of the proposed model to estimate the electrochemical-thermal responses with the average inference time of 0.0047 s per step. The application of the proposed model on the 26650 LFP cell also demonstrates the versatility on various shapes and types of LIBs. The systematic analysis on the 3D temperature distribution in the LIB of interest not only confirms the effectiveness of the internal temperature monitoring but also ensures the virtual sensing capability. The versatility of the proposed model underscores both design- and control- enabling solutions for battery thermal management.

Mixed transportation optimization model for oilfield water injection synergizing pipeline network and trucks

The water injection network is a common method in oil extraction processes, generally characterized by high energy consumption. Therefore, the adoption of scientifically sound and rational optimization schemes is crucial. However, due to the limited injection capacity of water injection station (WIS), when their supply is less than the demand of the injection wells, trucks are used for supplementary water injection. This paper introduces an oilfield water injection method under water injection pipeline and trucks coordination transport. An optimization model for oilfield water injection in this mixed transportation mode is established to address the supply-demand imbalance in the water injection network. The study uses a specific oilfield water injection system as a case study to validate the applicability of the mixed transportation water injection model (MTWI-Model) compared to the conventional water injection model (CWI-Model). The findings indicate that when only CWI-Model is used, the water volume from the injection station cannot meet the demands of the injection wells, leading to the cessation of some wells and potential overload of pumps in the station, thus affecting the normal operation of the water injection station and ultimately the oil recovery rate. Furthermore, the paper compares the optimization results of the mixed transportation model under two scenarios: fixed and non-fixed water intake points (namely MTWI-FP-Model and MTWI-NFP-Model). The results show that the mixed transportation mode with non-fixed water intake points is more economical, saving a daily cost of 632.28 Yuan/d compared to the fixed point scenario.

Strengthening Power Systems for Net Zero: A Review of the Role of Synchronous Condensers and Emerging Challenges

System strength is both supplied and demanded in a power system during normal operations and in the presence of disturbances. This is characterised by stable voltage and frequency, supporting renewable generation such as wind and solar. Because the retirement of synchronous generators reduces system strength supply, and the connection of new inverter-based resource (IBR) generators increases demand, there is an urgent need for new sources of system strength. This paper provides an overview of the challenges brought about by grid modernisation. It highlights tangible solutions provided by synchronous condensers (SCs) to bolster grid strength, stability, and reliability while accommodating the rising influx of renewable energy sources (RESs). Furthermore, this paper examines the role of SCs in improving weak grids, voltage control, power quality, short-circuit levels, and inertia management. It introduces the role of innovative hybrid synchronous condenser (HSC) systems to boost grid reliability and resilience. It also elaborates on the optimisation strategies for SC sizing, placement, and control and outlines economic aspects of their deployment. The review also highlights future directions and challenges in SC technology, emphasising the need for ongoing research and development to enhance system design and operation.

TRACK CIRCUITS INTERFERENCE RESISTANCE INCREASE UNDER THE TRACTION CURRENT INFLUENCE

Purpose. The aim of the work is to increase the electromagnetic compatibility of track circuits with the traction power supply system of railways under the influence of reverse traction current disturbances. Conducting research and analysis of the causes of malfunctions of rail circuits on electrified sections of the railway, existing means and methods of increasing the interference resistance of track circuits and ensuring the electromagnetic compatibility of signaling, centralization and blocking devices with the traction power supply system, and the development of effective technical solutions for normalizing the operation and rail circuits in the conditions influence of traction current interference. Conducting a study of the electromagnetic characteristics of the DT-1-150 track choke-transformer in normal mode and under the influence of external factors on the magnetic system. Methods. During the research, methods of comparative analysis, theories of electric and magnetic circuits, methods of spectral analysis of signals, as well as mathematical, schematic and physical modeling were used. Findings. Situations in which the traction current significantly affects the operation of the rail wheel equipment have been analyzed in the work. The effect of the traction current constant component on the normal operation mode of the track circuits is considered. The coefficients value of the choke-transformer DT-1-150 with traction current asymmetry was determined. A comparative analysis of resistance to reverse traction current disturbances of track receivers of station rail wheels used at the docking station was conducted. The principle-structural scheme of the protective unit for blocking the leakage of direct traction current interference on the section of alternating current traction was developed. The scientific novelty. The scientific novelty of the work consists in identifying and justifying the causes of some specific failures of track circuit; in confirming the integral effect of choke-transformer steel core saturation, created by the constant component of the traction current in the railway power supply system. Practical significance. Based on the conducted research, the interference resistance of the 25 Hz track circuit with the DSSH-16 track relay and DT-06-500S was confirmed. A protective valve block was developed, which prevents the flow of the first periods of the largest amplitude transient current in the track circuit its protects and ensures, thereby, normal operation of track circuit.

LESM-YOLO: An Improved Aircraft Ducts Defect Detection Model.

Aircraft ducts play an indispensable role in various systems of an aircraft. The regular inspection and maintenance of aircraft ducts are of great significance for preventing potential failures and ensuring the normal operation of the aircraft. Traditional manual inspection methods are costly and inefficient, especially under low-light conditions. To address these issues, we propose a new defect detection model called LESM-YOLO. In this study, we integrate a lighting enhancement module to improve the accuracy and recognition of the model under low-light conditions. Additionally, to reduce the model's parameter count, we employ space-to-depth convolution, making the model more lightweight and suitable for deployment on edge detection devices. Furthermore, we introduce Mixed Local Channel Attention (MLCA), which balances complexity and accuracy by combining local channel and spatial attention mechanisms, enhancing the overall performance of the model and improving the accuracy and robustness of defect detection. Finally, we compare the proposed model with other existing models to validate the effectiveness of LESM-YOLO. The test results show that our proposed model achieves an mAP of 96.3%, a 5.4% improvement over the original model, while maintaining a detection speed of 138.7, meeting real-time monitoring requirements. The model proposed in this paper provides valuable technical support for the detection of dark defects in aircraft ducts.