Relative Threshold-Based Event-Triggered Control for Nonlinear Constrained Systems With Application to Aircraft Wing Rock Motion

This paper concentrates upon the event-driven controller design problem for a class of nonlinear single input single output (SISO) parametric systems with full state constraints. A varying threshold for the triggering mechanism is exploited, which makes the communication more flexible. Moreover, from the viewpoint of energy conservation and consumption reduction, the system capability becomes better owing to the contribution of the proposed event triggered mechanism. In the meantime, the developed control strategy can avoid the Zeno behavior since the lower bound of the sample time is provided. The considered plant is in a lower-triangular form, in which the match condition is not satisfied. To ensure that all the states to retain in a predefined region, a barrier Lyapunov function (BLF) based adaptive control law is developed. Due to the existence of the parametric uncertainties, an adaptive algorithm is presented as an estimated tool. All the signals appearing in the closed-loop systems are then proven to be uniformly ultimately bounded (UUB). Meanwhile, the output of the system can track a given signal as far as possible. In the end, the effectiveness of the proposed approach is validated by an aircraft wing rock motion system

Multi-radial cyclone suction dust removal technology at coal mine belt transfer points

The dust hazard and management at the belt transfer point is one of the most important issues in achieving efficient, safe and clean production in coal mines. To address the problem of dust pollution at the transfer point and to reduce the dust hazard at the transfer point, a multi-radial cyclone suction dust removal technology is proposed for the belt transfer point based on the cyclone suction theory. The technology is based on a certain number of inlets and jet angles on the side wall of the vertical drop pipe, with the suction outlet set above the drop pipe. The principle of operation is that the incoming air-flow from the side wall of the drop pipe changes direction when it meets the side wall and the inlet jets interact with each other to form an upward flowing cyclone in the drop pipe. A simulated 3D solid model and a test platform for multi-radial cyclone suction dust removal at the belt transfer point are built. A combination of numerical simulations and experimental tests is used to study the distribution of air-flow and dust transport in the transfer point. In the numerical simulation and experimental tests, eight air inlets are provided on each of the four-side walls of the drop pipe at an angle of 10° to the horizontal, and four-air inlets are provided on the guide chute, with the air inlets oriented tangential to the circle of the particle release position on the lower belt. According to the cyclonic suction theory, the greater the inlet air velocity on the drop pipe, the greater the pressure difference between the boundary of the drop pipe and the center, and the better the effect on dust collection. The simulation results show that the best inlet air speed for the multi-radial cyclone suction technology is 8 m/s, where the dust of less than 50 μm and the dust of less than 30 μm from the impact of the coal with the lower belt can be collected during the drop. Comparing the dispersion of the coal before and after falling in the test, it is concluded that the proportion of particles smaller than 50 μm in the coal on the lower belt is reduced by 47.96%, and the proportion of particles smaller than 5 μm is reduced by 44.62% after the application of the dust removal technology. It reduces the proportion of harmful particles in the coal. By measuring the dust concentration at the ends of the guide chute and at the inlet, the test determines that the best inlet air speed for the multi-radial cyclone suction dust removal technology is 8 m/s. At this time, the dust concentrations at the left and right ends of the guide chute and at the inlet are the lowest, and the dust removal efficiency is 97.71% and 99.92% respectively, and the overall dust removal efficiency at the transfer point can reach more than 95%. The study proves that the multi-radial cyclone suction dust removal technology at the transfer point can solve the problem of dust pollution , improve the working environment

Aerosols in the E3SM Version 1: New Developments and Their Impacts on Radiative Forcing

The new Energy Exascale Earth System Model Version 1 (E3SMv1) developed for the U.S. Department of Energy has significant new treatments of aerosols and lightâ absorbing snow impurities as well as their interactions with clouds and radiation. This study describes seven sets of new aerosolâ related treatments (involving emissions, new particle formation, aerosol transport, wet scavenging and resuspension, and snow radiative transfer) and examines how they affect global aerosols and radiative forcing in E3SMv1. Altogether, they give a reduced total aerosol radiative forcing (â 1.6 W/m2) and sensitivity in cloud liquid water to aerosols, but an increased sensitivity in cloud droplet size to aerosols. A new approach for H2SO4 production and loss largely reduces a low bias in small particles concentrations and leads to substantial increases in cloud condensation nuclei concentrations and cloud radiative cooling. Emitting secondary organic aerosol precursor gases from elevated sources increases the column burden of secondary organic aerosol, contributing substantially to global clearâ sky aerosol radiative cooling (â 0.15 out of â 0.5 W/m2). A new treatment of aerosol resuspension from evaporating precipitation, developed to remedy two shortcomings of the original treatment, produces a modest reduction in aerosols and cloud droplets; its impact depends strongly on the model physics and is much stronger in E3SM Version 0. New treatments of the mixing state and optical properties of snow impurities and snow grains introduce a positive presentâ day shortwave radiative forcing (0.26 W/m2), but changes in aerosol transport and wet removal processes also affect the concentration and radiative forcing of lightâ absorbing impurities in snow/ice.Plain Language SummaryAerosol and aerosolâ cloud interactions continue to be a major uncertainty in Earth system models, impeding their ability to reproduce the observed historical warming and to project changes in global climate and water cycle. The U.S. DOE Energy Exascale Earth System Model version 1 (E3SMv1), a stateâ ofâ theâ science Earth system model, was developed to use exascale computing to address the grand challenge of actionable predictions of variability and change in the Earth system critical to the energy sector. It has been publicly released with new treatments in many aspects, including substantial modifications to the physical treatments of aerosols in the atmosphere and lightâ absorbing impurities in snow/ice, aimed at reducing some known biases or correcting model deficiencies in representing aerosols, their life cycle, and their impacts in various components of the Earth system. Compared to its predecessors (without the new treatments) and observations, E3SMv1 shows improvements in characterizing global distributions of aerosols and their radiative effects. We conduct sensitivity experiments to understand the impact of individual changes and provide guidance for future development of E3SM and other Earth system models.Key PointsA description and assessment of new aerosol treatments in the Energy Exascale Earth System Model Version 1 (E3SMv1) is providedContributions to the total aerosolâ related radiative forcing by individual new treatments and different processes are quantifiedSome of the new treatments are found to depend on model physics and require further improvement for E3SM or other Earth system modelsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153241/1/jame21034-sup-0001-Figure_SI-S01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153241/2/jame21034.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153241/3/jame21034_am.pd

Investigation of the first and second aerosol indirect effects using data from the May 2003 Intensive Operational Period at the Southern Great Plains

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95668/1/jgrd12974.pd

Toward understanding of differences in current cloud retrievals of ARM ground-based measurements

Accurate observations of cloud microphysical properties are needed for evaluating and improving the representation of cloud processes in climate models and better estimate of the Earth radiative budget. However, large differences are found in current cloud products retrieved from ground-based remote sensing measurements using various retrieval algorithms. Understanding the differences is an important step to address uncertainties in the cloud retrievals. In this study, an in-depth analysis of nine existing ground-based cloud retrievals using ARM remote sensing measurements is carried out. We place emphasis on boundary layer overcast clouds and high level ice clouds, which are the focus of many current retrieval development efforts due to their radiative importance and relatively simple structure. Large systematic discrepancies in cloud microphysical properties are found in these two types of clouds among the nine cloud retrieval products, particularly for the cloud liquid and ice particle effective radius. Note that the differences among some retrieval products are even larger than the prescribed uncertainties reported by the retrieval algorithm developers. It is shown that most of these large differences have their roots in the retrieval theoretical bases, assumptions, as well as input and constraint parameters. This study suggests the need to further validate current retrieval theories and assumptions and even the development of new retrieval algorithms with more observations under different cloud regimes

An analysis of some inference procedures derived via relative surprise

grantor: University of TorontoThis thesis is concerned with the concept of relative surprise as a technique for deriving inferences. Further refinements in the development of relative surprise are made beyond those presented in Evans (1997). Relative surprise is applied to the normal location-scale model and the properties of the inferences derived are studied. Similarly relative surprise is applied to the one factor random effects model and inferences are derived for the intraclass correlation coefficient. The thesis develops a technique for using the distribution of the cross-validational observed relative surprise under all possible splits for model checking, hyperparameter estimation and model selection inferences.Ph.D

Entropy Functions on Two-Dimensional Faces of Polymatroidal Region of Degree Four

In this paper, we characterize entropy functions on the 2-dimensional faces of the polymatroidal region $\Gamma_4$. We enumerate all 59 types of 2-dimensional faces of $\Gamma_4$ and fully characterized entropy functions on 27 types of them, among which 4 types are non-trivial.Comment: accepted for 2023 IEEE International Symposium on Information Theory(ISIT

Fuzzy approximate disturbance decoupling of MIMO nonlinear systems by back stepping approach. Fuzzy sets and systems

Abstract The concept of fuzzy approximate disturbance decoupling is introduced for a class of MIMO nonlinear systems with unknown nonlinearities. Based on the backstepping technique, a direct adaptive fuzzy almost disturbance decoupling control scheme is proposed. The proposed fuzzy controllers guarantee internal uniform ultimate boundedness of the closed-loop adaptive systems and render a bounded approximate L 2 gain from the disturbance input to the output. The main characteristics of the proposed algorithm is that the adaptive fuzzy controllers have a simple structure, and less adaptive parameters than the existing results. At last, the developed design scheme is applied to control a two continuous stirred tank reactor process. The simulation results illustrate the effectiveness of the method proposed in this paper