Q-stacking prediction model considering wind speed error correction

In order to improve the accuracy of wind speed forecasting in wind farms, an ensemble-enhanced combined forecasting model is proposed considering error correction. First establish five independent base learners, build a two-layer Stacking ensemble model to fuse the prediction results of each base learner, and divide the input data by cross-validation to improve the generalization ability of the model. Then use the model-free learning framework Q learning selects the optimal model in the base learner to correct the preliminary prediction error and obtain the final prediction result. Select the actual wind farm measured data in different seasons to simulate the prediction effect of the model, and verify the prediction ability of the proposed model through comparative analysis. The results show that the model has high prediction accuracy with ε = 0.093.

Output-Feedback Position Tracking Servo System with Feedback Gain Learning Mechanism via Order-Reduction Speed-Error-Stabilization Approach

This paper presents a novel trajectory-tracking technique for servo systems treating only the position measurement as the output subject to practical concerns: system parameter and load uncertainties. There are two main contributions: (a) the use of observers without system parameter information for estimating the position reference derivative and speed and acceleration errors and (b) an order reduction exponential speed error stabilizer via active damping injection to enable the application of a feedback-gain-learning position-tracking action. A hardware configuration using a QUBE-servo2 and myRIO-1900 experimentally validates the closed-loop improvement under various scenarios.

Characterizing Buoy Wind Speed Error in High Winds and Varying Sea State with ASCAT and ERA5

Buoys provide key observations of wind speed over the ocean and are routinely used as a source of validation data for satellite wind products. However, the movement of buoys in high seas and the airflow over waves might cause inaccurate readings, raising concern when buoys are used as a source of wind speed comparison data. The relative accuracy of buoy winds is quantified through a triple collocation (TC) exercise comparing buoy winds to winds from ASCAT and ERA5. Differences between calibrated buoy winds and ASCAT are analyzed through separating the residuals by anemometer height and testing under high wind-wave and swell conditions. First, we converted buoy winds measured near 3, 4, and 5 m to stress-equivalent winds at 10 m (U10s). Buoy U10s from anemometers near 3 m compared notably lower than buoy U10s from anemometers near 4 and 5 m, illustrating the importance of buoy choice in comparisons with remote sensing data. Using TC calibration of buoy U10s to ASCAT in pure wind-wave conditions, we found that there was a small, but statistically significant difference between height adjusted buoy winds from buoys with 4 and 5 m anemometers compared to the same ASCAT wind speed ranges in high seas. However, this result does not follow conventional arguments for wave sheltering of buoy winds, whereby the lower anemometer height winds are distorted more than the higher anemometer height winds in high winds and high seas. We concluded that wave sheltering is not significantly affecting the winds from buoys between 4 and 5 m with high confidence for winds under 18 ms−1. Further differences between buoy U10s and ASCAT winds are observed in high swell conditions, motivating the need to consider the possible effects of sea state on ASCAT winds.

Evaluation of Graphical User Interfaces by the Search Time for Information Objects

The paper discusses the problem of poor quality of graphical user interfaces used for various software products. The provided analysis shows that modern software has poor-quality interfaces, and there are no flexible programs for evaluating such interfaces. The paper highlights and describes the characteristics that are used to assess the quality of interfaces, such as operator speed, error rates, skill retention, and subjective satisfaction. A formalized approach to assess the speed of searching for information and functional objects is proposed. It is based on such characteristics as the time of fixation of the gaze, movement of the eye, the volume of a person’s operative memory, the zone of clear vision, the path of the user’s gaze information search. An algorithm for estimating the speed of searching for information and functional elements is proposed. This algorithm can be implemented and used for further design of a software application based on it. The algorithm makes it possible to automatically evaluate both a particular interface and to compare the interfaces of different programs.

Speed fluctuations of bacterial replisomes

Replisomes are multi-protein complexes that replicate genomes with remarkable speed and accuracy. Despite their importance, the dynamics of replisomes along the genome is poorly characterised, especially in vivo. In this paper, we link the replisome dynamics with the DNA abundance distribution measured in an exponentially growing bacterial population. Our approach permits to accurately infer the replisome dynamics along the genome from deep sequencing measurements. As an application, we experimentally measured the DNA abundance distribution in Escherichia coli populations growing at different temperatures. We find that the average replisome speed increases nearly five-fold between 17°C and 37°C. Further, we observe wave-like variations of the replisome speed along the genome. These variations are correlated with previously observed variations of the mutation rate along the genome. We interpret this correlation as a speed--error trade-off and discuss its possible dynamical origin. Our approach has the potential to elucidate replication dynamics in E. coli mutants and in other bacterial species.

Optimization of DC motor speed control based on fuzzy logic-PID controller

In this paper the PID controller and the Fuzzy Logic Controller (FLC) are used to control the speed of separately excited DC motors. The proportional, integral and derivate (KP, KI, KD) gains of the PID controller are adjusted according to Fuzzy Logic rules. The FLC cotroller is designed according to fuzzy rules so that the system is fundamentally robust. Twenty-five fuzzy rules for self-tuning of each parameter of the PID controller are considered. The FLC has two inputs; the first one is the motor speed error (the difference between the reference and actual speed) and the second one is a change in the speed error (speed error derivative). The output of the FLC, i.e. the parameters of the PID controller, are used to control the speed of the separately excited DC Motor. This study shows that the precisiom feature of the PID controllers and the flexibllity feature of the fuzzy controller are presented in the fuzzy self-tuning PID controller. The fuzzy self – tuning approach implemented on the conventional PID structure improved the dynamic and static response of the system. The salient features of both conventional and fuzzy self-tuning controller outputs are explored by simulation using MATLAB. The simulation results demonstrate that the proposed self-tuned PID controller i.plementd a good dynamic behavior of the DC motor i.e. perfect speed tracking with a settling time, minimum overshoot and minimum steady state errorws.

An Extraction Method of Volleyball Spiking Trajectory and Teaching Based on Wireless Sensor Network

It is helpful to analyze volleyball spiking technology and improve spiking quality to extract volleyball spiking trajectory. This article studies the extraction method and teaching method of volleyball spiking trajectory based on a wireless sensor network. The acceleration sensor and gyroscope sensor are used to collect the spiking action state information of volleyball players. The collected information is transmitted to the PC terminal through the wireless sensor network, including physical layer, data link layer, network layer, transmission layer, and application layer, using the LEACH clustering routing protocol algorithm. In the PC terminal, the feedback filtering method is used to preprocess the received information and calculate the integral of each sensor node’s acceleration, connecting the spatial coordinates of each time to obtain the upper limb trajectory in three-dimensional space and realize the trajectory extraction of volleyball spike action. The experimental results show that the position error is less than 0.01 m and the speed error is less than 0.15 m/s. The application of this method in volleyball teaching can effectively improve the quality of volleyball teaching.

A People-Counting and Speed-Estimation System Using Wi-Fi Signals

Counting the number of people and estimating their walking speeds are essential in crowd control and flow. In this work, we propose a system that uses prevalent Wi-Fi signals to identify the number of people entering and leaving a room through a door. It selects the best subcarrier of Wi-Fi signals and applies the Hampel filter to remove outlier information first. Then, it employs a double threshold method to determine the start and end times of entering or leaving. Afterward, it compares the detected signals with the precollected database using the dynamic time-warping algorithm and determines the number of people. It uses a variance threshold method to identify the states of entering or leaving. It also employs a nonlinear fitting approach to calculate the walking speeds. The experiments show that, in a large empty laboratory, the accuracy rates in determining the number of people are 100% for one person, 81% for two persons, and 95% for three persons. In a small office, the accuracy rates for detecting the number of people are 98% for one or two persons, 82% for three persons, 93% for four, and 75% for five persons. For the walking speed estimation, the accuracy rate for a speed error of less than 0.2410 m/s is 75% for a single person.