Prescribed Performance Tracking Control of Time-Delay Nonlinear Systems With Output Constraints

The problem of prescribed performance tracking control for unknown time-delay nonlinear systems subject to output constraints is dealt with in this paper. In contrast with related works, only the most fundamental requirements, i.e., boundedness and the local Lipschitz condition, are assumed for the allowable time delays. Moreover, we focus on the case where the reference is unknown beforehand, which renders the standard prescribed performance control designs under output constraints infeasible. To conquer these challenges, a novel robust prescribed performance control approach is put forward in this paper.Herein, a reverse tuning function is skillfully constructed and automatically generates a performance envelop for the tracking error. In addition, a unified performance analysis framework based on proof by contradiction and the barrier function is established to reveal the inherent robustness of the control system against the time delays. It turns out that the system output tracks the reference with a preassigned settling time and good accuracy,without constraint violations. A comparative simulation on a two-stage chemical reactor is carried out to illustrate the above theoretical findings.

Finite-time Prescribed Performance Time-Varying Formation Control for Second-Order Multi-Agent Systems With Non-Strict Feedback Based on a Neural Network Observer

This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown nonlinearities.To eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the system.In addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader agent.To address this problem,a neural network state observer based on the leader state information is designed.Then,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite time.Finally,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm.

Dynamic performance and parameter optimization of a half-vehicle system coupled with an inerter-based X-structure nonlinear energy sink

Inspired by the demand of improving the riding comfort and meeting the lightweight design of the vehicle, an inerter-based X-structure nonlinear energy sink(IXNES) is proposed and applied in the half-vehicle system to enhance the dynamic performance. The X-structure is used as a mechanism to realize the nonlinear stiffness characteristic of the NES, which can realize the flexibility, adjustability, high efficiency, and easy operation of nonlinear stiffness, and is convenient to apply in the vehicle suspension, and the inerter is applied to replacing the mass of the NES based on the mass amplification characteristic. The dynamic model of the half-vehicle system coupled with the IX-NES is established with the Lagrange theory, and the harmonic balance method(HBM) and the pseudo-arc-length method(PALM) are used to obtain the dynamic response under road harmonic excitation. The corresponding dynamic performance under road harmonic and random excitation is evaluated by six performance indices, and compared with that of the original half-vehicle system to show the benefits of the IX-NES. Furthermore, the structural parameters of the IX-NES are optimized with the genetic algorithm. The results show that for road harmonic and random excitation, using the IX-NES can greatly reduce the resonance peaks and root mean square(RMS) values of the front and rear suspension deflections and the front and rear dynamic tire loads, while the resonance peaks and RMS values of the vehicle body vertical and pitching accelerations are slightly larger.When the structural parameters of the IX-NES are optimized, the vehicle body vertical and pitching accelerations of the half-vehicle system could reduce by 2.41% and 1.16%,respectively, and the other dynamic performance indices are within the reasonable ranges.Thus, the IX-NES combines the advantages of the inerter, X-structure, and NES, which improves the dynamic performance of the half-vehicle system and provides an effective option for vibration attenuation in the vehicle engineering.

Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams

Replaceable flexural and shear fuse-type coupling beams are used in hybrid coupled shear wall(HCSW)systems,enabling concrete buildings to be promptly recovered after severe earthquakes.This study aimed to analytically evaluate the seismic behavior of flexural and shear fuse beams situated in short-,medium-and high-rise RC buildings that have HCSWs.Three building groups hypothetically located in a high seismic hazard zone were studied.A series of 2D nonlinear time history analyses was accomplished in OpenSees,using the ground motion records scaled at the design basis earthquake level.It was found that the effectiveness of fuses in HCSWs depends on various factors such as size and scale of the building,allowable rotation value,inter-story drift ratio,residual drift quantity,energy dissipation value of the fuses,etc.The results show that shear fuses better meet the requirements of rotations and drifts.In contrast,flexural fuses dissipate more energy,but their sectional stiffness should increase to meet other requirements.It was concluded that adoption of proper fuses depends on the overall scale of the building and on how associated factors are considered.

A Systematic Literature Review on Task Allocation and Performance Management Techniques in Cloud Data Center

As cloud computing usage grows,cloud data centers play an increasingly important role.To maximize resource utilization,ensure service quality,and enhance system performance,it is crucial to allocate tasks and manage performance effectively.The purpose of this study is to provide an extensive analysis of task allocation and performance management techniques employed in cloud data centers.The aim is to systematically categorize and organize previous research by identifying the cloud computing methodologies,categories,and gaps.A literature review was conducted,which included the analysis of 463 task allocations and 480 performance management papers.The review revealed three task allocation research topics and seven performance management methods.Task allocation research areas are resource allocation,load-Balancing,and scheduling.Performance management includes monitoring and control,power and energy management,resource utilization optimization,quality of service management,fault management,virtual machine management,and network management.The study proposes new techniques to enhance cloud computing work allocation and performance management.Short-comings in each approach can guide future research.The research’s findings on cloud data center task allocation and performance management can assist academics,practitioners,and cloud service providers in optimizing their systems for dependability,cost-effectiveness,and scalability.Innovative methodologies can steer future research to fill gaps in the literature.

Generalized autoencoder-based fault detection method for traction systems with performance degradation

Fault diagnosis of traction systems is important for the safety operation of high-speed trains.Long-term operation of the trains will degrade the performance of systems,which decreases the fault detection accuracy.To solve this problem,this paper proposes a fault detection method developed by a Generalized Autoencoder(GAE)for systems with performance degradation.The advantage of this method is that it can accurately detect faults when the traction system of high-speed trains is affected by performance degradation.Regardless of the probability distribution,it can handle any data,and the GAE has extremely high sensitivity in anomaly detection.Finally,the effectiveness of this method is verified through the Traction Drive Control System(TDCS)platform.At different performance degradation levels,our method’s experimental results are superior to traditional methods.

A PID Tuning Approach for Inertial Systems Performance Optimization

In the practice of control the industrial processes, proportional-integral-derivative controller remains pivotal due to its simple structure and system performance-oriented tuning process. In this paper are presented two approaches for synthesis the proportional-integral-derivative controller to the models of objects with inertia, that offer the procedure of system performance optimization based on maximum stability degree criterion. The proposed algorithms of system performance optimization were elaborated for model of objects with inertia second and third order and offer simple analytical expressions for tuning the PID controller. Validation and verification are conducted through computer simulations using MATLAB, demonstrating successful performance optimization and showcasing the effectiveness PID controllers’ tuning. The proposed approaches contribute insights to the field of control, offering a pathway for optimizing the performance of second and third-order inertial systems through robust controller synthesis.

The Impact of Health Information Technology on Hospital Performance: A Systematic Integrative Literature Review

Objective: To review, categorise, and synthesise findings from literature on health information technology (HIT) functionalities, HIT use, and the impact of HIT on hospital performance. Materials and Methods: We conducted a systematic integrative literature review based on a compre-hensive database search. To organise, categorise and synthesise the ex-isting literature, we adopted the affordance actualization theory. To align the literature with our research framework, we used four categories: 1) the functionalities of HIT and how these functionalities are measured;2) use and immediate outcomes of HIT functionalities;3) different perfor-mance indicators and how HIT functionalities affect them;and 4) what hospital characteristics influence the outcome of hospital performance. Results: Fifty-two studies were included. We identified four types of HIT. Only ten studies (19.2%) define the use of HIT by explicitly meas-uring the use rate of HIT. We identified five dimensions of hospital per-formance indicators. Every dimension showed mixed results;however, in general, HIT has a positive impact on mortality and patient readmis-sions. We found several hospital characteristics that may affect the rela-tionship between HIT and hospital-level outcomes. Discussion: Further efforts should focus on embedded research on HIT functionalities, use and effects of HIT implementations with more performance indicators and adjusted for hospital characteristics. Conclusion: The proposed framework could help hospitals and researchers make decisions regard-ing the functionalities, use and effects of HIT implementation in hospi-tals. Given our research outcomes, we suggest future research opportuni-ties to improve understanding of how HIT affects hospital performance. .

Review: update on performance assessment and monitoring systems for ophthalmologists

Performance assessment and monitoring systems are the process by which ophthalmologists demonstrate they are fit to continue practicing.Revalidation is the process by which licensed doctors are legally required to demonstrate to medical regulators that they are up to date and fit to practice in order to maintain their medical license,and began in the United Kingdom(UK)in 2012 following well-publicized events.Recertification is a different process which began in North America and demonstrates doctors have maintained competence,without involvement of external stakeholders.Arguments for and against the concept of performance assessment are reviewed.Stakeholders in performance assessment,whether part of the process or not,are doctors themselves,peers and other health care providers,patients,hospitals and health systems,medical regulators,and health policy makers.Early models of performance assessment included portfolios,credit accumulation,and closed-book examinations.Models are in evolution with the value of formative rather than summative assessments,and the need for methods of assessing procedural competency increasingly recognized.Emerging methods of performance assessment of practicing ophthalmologists include use of performance indicators,simulation,and workplace-based assessments.Alternate methods of assuring the public by improved detection of outliers are discussed.Despite weak evidence supporting performance assessments in demonstrating continuing competency to practice,the process is gradually being accepted worldwide.Further research into optimum methods of performance assessment and monitoring processes is required,along with cost-benefit analysis.

Correlation Study of Operational Data and System Performance of District Cooling System with Ice Storage

The district cooling system (DCS) with ice storage can reduce the peak electricity demand of the business district buildings it serves, improve system efficiency, and lower operational costs. This study utilizes a monitoring and control platform for DCS with ice storage to analyze historical parameter values related to system operation and executed operations. We assess the distribution of cooling loads among various devices within the DCS, identify operational characteristics of the system through correlation analysis and principal component analysis (PCA), and subsequently determine key parameters affecting changes in cooling loads. Accurate forecasting of cooling loads is crucial for determining optimal control strategies. The research process can be summarized briefly as follows: data preprocessing, parameter analysis, parameter selection, and validation of load forecasting performance. The study reveals that while individual devices in the system perform well, there is considerable room for improving overall system efficiency. Six principal components have been identified as input parameters for the cold load forecasting model, with each of these components having eigenvalues greater than 1 and contributing to an accumulated variance of 87.26%, and during the dimensionality reduction process, we obtained a confidence ellipse with a 95% confidence interval. Regarding cooling load forecasting, the Relative Absolute Error (RAE) value of the light gradient boosting machine (lightGBM) algorithm is 3.62%, Relative Root Mean Square Error (RRMSE) is 42.75%, and R-squared value (R2) is 92.96%, indicating superior forecasting performance compared to other commonly used cooling load forecasting algorithms. This research provides valuable insights and auxiliary guidance for data analysis and optimizing operations in practical engineering applications. .

Construction Method for Performance Management Curriculum Content System Based on Knowledge Graph

Performance Management is the core course of human resource management major,but its knowledge points lack multi-dimensional correlations.There are problems such as scattered content and unclear system,and it is urgent to reconstruct the content system of the course.Knowledge graph technology can integrate massive and scattered information into an organic structure through semantic correlation and reasoning.The application of knowledge graph to education and teaching can promote scientific and personalized teaching evaluation and better realize individualized teaching.This paper systematically combs the knowledge points of Performance Management course and forms a comprehensive knowledge graph.The knowledge point is associated with specific questions to form the problem map of the course,and then the knowledge point is further associated with the ability target to form the ability map of the course.Then,the knowledge point is associated with teaching materials,question bank and expansion resources to form a systematic teaching database,thereby giving the method of building the content system of Performance Management course based on the knowledge map.This research can be further extended to other core management courses to realize the deep integration of knowledge graph and teaching.

Using multi-criteria decision-making and machine learning for football player selection and performance prediction:a systematic review

Evaluating and selecting players to suit football clubs and decision-makers (coaches, managers, technical, and medical staff) is a difficult process from a managerial-financial and sporting perspective. Football is a highly competitive sport where sponsors and fans are attracted by success. The most successful players, based on their characteristics (criteria and sub-criteria), can influence the outcome of a football game at any given time. Consequently, the D-day of selection should employ a more appropriate approach to human resource management. To effectively address this issue, a detailed study and analysis of the available literature are needed to assist practitioners and professionals in making decisions about football player selection and hiring. Peer-reviewed journals were selected for collecting published papers between 2018 and 2023. A total of 66 relevant articles (journal articles, conference articles, book sections, and review articles) were selected for evaluation and analysis. The purpose of the study is to present a systematic literature review (SLR) on how to solve this problem and organize the published research papers that answer our four research questions.

Implementation of heat exchanger performance testing system of heat transfer and flow resistance

A heat transfer performance testing system is presented with its hardware structure, operation principle, and software control and measurement system. Working fluids of the subsystem include thermal conducting oil, compressed air, glycol water solution and water as the heating fluids, and air and water as the cooling fluids. The heat transfer performance testing of heat exchangers can be conducted not only for a conventional one heating fluid to one cooling fluid, but also for a compound air cooling heat exchanger with two or three heating fluids in parallel or in series. The control and measurement system is implemented based on a LabVIEW software platform, consisting of the data acquisition and process system, and the automotive operation and control system. By using advanced measuring instruments combined with sound computer software control, the testing system has characteristics of a compact structure, high accuracy, a wide range of testing scope and a friendly operation interface. The uncertainty of the total heat transfer coefficient K is less than 5%. The testing system provides a reliable performance testing platform for designing and developing new heat exchangers.

Performance analysis of heat pump based on a new solar air-source heat pump heating system

To further improve the utilization efficiency of solar energy and the performance of solar heat pump heating systems,a new heating mode of a solar air-source heat pump（SASHP）is proposed,and the characteristics and performance of the heat pump part of this new heating system are studied.Based on a SASHP with 10 kW,the mathematical model of this system is built,and the characteristics and performance are concluded from the simulation analysis at different environmental temperatures and output water temperatures.The results show that the performance of heat pumps can be greatly improved based on the new SASHP.When the environmental temperature is 7 ℃,the coefficient of performance（COP）of the air-source heat pump（ASHP）can be increased by 26% at most.This paper sets up a base for further study on the heating system with this new SASHP in the heating season.

Bayesian and Multiple Bayesian Analysis of the Reliability Performances for Series System with Cold Standby Units

By using Bayesian and multiple Bayesian method, the failure probability, reliability and mean time to failure(MTTF) of series system with cold standby units are estimated. At last, we compare the two estimators by means of Monte_Carlo simulation.

Performance analysis of aircraft low-power thermoelectric refrigeration system

An optimal design method for an aircraft low-power thermoelectric refrigeration system（TRS）is proposed using an existing experimental model as the research platform under given aircraft flight conditions.The variation curves of the cooling capacities and the refrigeration coefficients of the system running at three flight altitudes are investigated.The performance of the system is evaluated by the minimum-entropy-generation method and the performance penalty is also calculated.The power variation curves of the cooling system are obtained by an electric power experiment.The peak values of these curves are less than the maximal electric power supply of airborne equipment,proving that the use of the low-power TRS for airborne equipment is feasible.The COP,cooling capacity and entropy generation of the system are relative to the flight altitude and the current of the TRS.Through the analyses of these data,the optimal values of the COP are obtained,and the optimization measures are proposed to maximize the use of the advantages of the TRS.

Modeling Photovoltaic Performances of BTBPD-PC61BM System via Density Functional Theory Calculations

Designing and fabricating high-performance photovoltaic devices have remained a major challenge in organic solar cell technologies. In this work, the photovoltaic performances of BTBPD-PC61BM system were theoretically investigated by means of density functional theory calculations coupled with the Marcus charge transfer model in order to seek novel photovoltaic systems. Moreover, the hole-transfer properties of BTBPD thin-film were also studied by an amorphous cell with 100 BTBPD molecules. Results revealed that the BTBPD- PC61BM system possessed a middle-sized open-circuit voltage of 0.70 V, large short-circuit current density of 16.874 mA/cm2, large fill factor of 0.846, and high power conversion effi- ciency of 10%. With the Marcus model, the charge-dissociation rate constant was predicted to be as fast as 3.079×10^13 s^-1 in the BTBPD-PC61BM interface, which was as 3-5 orders of magnitude large as the decay （radiative and non-radiative） rate constant （108-10^10 s^-1）, indicating very high charge-dissociation efficiency （-100%） in the BTBPD-PC61BM system. Furthermore, by the molecular dynamics simulation, the hole mobility for BTBPD thin-film was predicted to be as high as 3.970× 10^-3 cm^2V^-1s^-1, which can be attributed to its tight packing in solid state.

Performance Optimization of Agricultural Machinery Monitoring WebGIS System Based on ASP.NET

ASP.NET-based agricultural machinery monitoring WEBGIS is flexible and dynamic,but this flexibility and dynamic characteristics reduce the performance of WEBGIS.Therefore,it is necessary to use built-in optimization features of.NET Framework,some performance optimization techniques in program design and ASP.NET cache technology to reduce the loading of server,and make the designed system work more efficiently.

Improving Geese Production Performance in “Goose-Fish” Production System by Competitive Reduction of Pathogenic Bacteria in Pond Water

This study investigated whether competitive reduction of pathogenic bacteria growth in pond water alleviates lipopolysaccharide （LPS） contamination and improves geese production performances in the ＂goose-fish＂ production system, thereby providing the potential for an improved technique for ecological water fowl production. In the first experiment, 240 Magang goslings of 15-d age were randomly and equally allocated into 16 ＂yard and pond＂ pens using a 2-2 factorial design with 4 replications per treatment. In the 55-d experimental period, the goslings received 2 main treatments： supplementation of Bacillus subtilis spores in the feed and addition of photosynthetic bacteria （PSB） to the pond water. Both B. subtilis spores and PSB treatments significantly suppressed water counts of Gram-negative bacteria Escherichia coli, Salmonella and Shigella, and LPS concentrations in pond water and in gosling blood （P〈0.05）. As the result, the two treatments significantly improved gosling weight gain and carcass quality, marked by enhanced breast and leg muscle percentages and reduced subcutaneous fat proportions （P〈0.05）. Moreover, the improved effects of B. subtilis spores and PSB treatments were additive. In the second experiment, 1 160 adult geese were induced to start egg laying from May throughout the summer months. The geese were separated equally into control and experimental flocks to fit into 2 integration production units, with a density of 1 bird m-2 meter on pond water. Experimental flock geese were treated with B. subtilis spores in feed and PSB in the pond water for the duration of the study. Such treatment combination significantly depressed the growth of E. coli, Salmonella and Shigella in the pond water and reduced LPS concentrations both in pond water and in geese blood （P〈0.01）. As a result, egg fertility, fertile and set egg hatchabilities were all improved in the treated flock. Results from both growing goslings and breeding geese demonstrated that water bacteria pollution can be competitively reduced by supplementation with B. subtilis spores via the feed and addition of PSB in pond water, each of which reduces LPS contamination to geese and improves production performances. Micro- ecological agents such as B. subtilis spores and PSB improve water quality and provide a simple ecological technique for the ＂water fowl-fish＂ integrative production system.