Search

To improve the uniformity of asphalt mixtures, optimizing the particle distribution is essential, and the screw conveyor of paver plays a critical role in this process. In this regard, a parameter optimization strategy based on the discrete element method and response surface methodology (RSM) is proposed. First, a discrete element model is developed for spiral material separation and asphalt mixture particles. Next, uniformity evaluation indicators are used to analyze the impact of individual parameters on particle uniformity. Then, simulation experiments are conducted under varying material level coefficients and rotational speeds, and a regression model is developed to analyze the impact of coupling factors using RSM. Afterward, different algorithms are employed to optimize the parameters of the model, and the results show that the particle swarm optimization algorithm is better than the traditional hill climbing algorithm. Last, field tests are conducted to verify the feasibility of the proposed optimization strategy. The optimal theoretical parameter of the material level coefficient is 0.95, and the rotational speed is 53 rpm. Overall, the proposed strategy offers an effective and accurate model for simulating the process of particle separation, which can lead to improved uniformity of asphalt mixtures. [ABSTRACT FROM AUTHOR]

Rotational inertial navigation system (RINS) could improve the navigation performance by rotating the IMU around gimbals, and the structure and function of the dual-axis RINS also help realize the process of self-calibration. However, the gyro–accelerometer asynchronous time is not considered in current studies. Coupled into the navigation error, the gyro–accelerometer asynchronous time can lead to velocity accuracy decline during the process of rotation. Therefore, the modeling and calibration of the gyro–accelerometer asynchronous time would enhance the systemic reliability. In this article, in order to solve the abovementioned problem: 1) we model the gyro–accelerometer asynchronous time and perform an error analysis of gyro–accelerometer asynchronous time; 2) we propose a compensation method of the outer lever arm to improve the accuracy of the observed velocity and position; and 3) we derive a continuous linear 40-D RINS error model considering the abovementioned two error parameters compared with the traditional method, the PWCS method, and the SVD method is utilized to provide the observability degrees of the proposed state during the self-calibration process. Experimental results illustrated that the proposed method can improve the accuracy in the long-endurance navigation. [ABSTRACT FROM AUTHOR]

A significant issue of land vehicle navigation is in-motion attitude alignment of the odometer (OD)-aided strapdown inertial navigation system (SINS). The consecutive OD outliers can occur due to sudden wheel slipping and skidding while vehicle maneuvering. They seriously reduce the robustness and precision of attitude alignment. In this paper, we investigate a robust in-motion attitude alignment method for the OD-aided SINS. The method consists of in-motion coarse alignment and in-motion fine alignment. In the in-motion coarse alignment process, we developed Huber's M-estimation and integral formula based robust Kalman filter (HRKF/IF-CA), which can restrain the interference of consecutive OD outliers on reconstructed observation vectors. Thus, HRKF/IF-CA can contribute to better coarse attitude results. The next process is in-motion fine alignment. Under the popular repeated backtracking scheme, we investigate HRKF based fine alignment (HRKF-FA) with the SINS/OD summed measurement model. HRKF-FA can refine attitude alignment and restrain the interference of consecutive OD outliers simultaneously. Finally, the proposed method is evaluated by simulation and vehicle test. The attitude alignment results show that this method can achieve reasonable attitude results, and the interference of consecutive OD outliers caused by sudden wheel slipping and skidding can be greatly restrained. [ABSTRACT FROM AUTHOR]

In order to understand rice blast resistance gene patterns in rice landraces from Myanmar and Laos, we analysed the Pita, Pib, Pikh, Pi9 and Pi5 genes in 80 landraces through the use of functional molecular markers and functional fragment sequencing. These landraces were separated into four haplotypes (H1–H4) based upon three mutations identified in the Pita sequence. All four haplotypes were detected among landraces from Myanmar, whereas only the H1 and H2 haplotypes were detected among landraces from Laos. We additionally grouped landraces carrying 0–4 resistance genes into 18 genotypes based upon their resistance-susceptibility patterns and found that 16 of these genotypes were detected among Myanmar landraces at relative frequencies ranging from 2.50–12.50%, while 10 were detected among landraces from Laos at relative frequencies of 2.50–42.50%. The 'Pib(+) pikh(−) pi9(−) pi5(−) pita(−)' genotype was found to be dominant, accounting for 12.5 and 42.5% of landraces from Myanmar and Laos, respectively. The Pib, Pikh, Pi5 and Pita genes were detected in 52.50, 32.50, 37.50 and 30.00% of landraces from Myanmar respectively, whereas they were detected in 52.50, 12.50, 30.00 and 17.50% of landraces from Laos, respectively. The Pi9 gene was rarely detected among analysed landraces and was particularly rare in those from Laos. These findings suggest that rice landraces from Myanmar are more genetically diverse than those from Laos, with clear differences in blast resistance gene patterns between landraces from these two countries. [ABSTRACT FROM AUTHOR]

Most image encryption algorithms encrypt the whole image, but only part of the data is important in the image. In this paper, we propose a multidimensional chaotic image encryption algorithm based on the region of interest (ROI). The histogram of oriented gradients (HOG) feature extraction and support vector machine (SVM) are used to separate the region of interest from the whole image. Then, the region of interest pixels is messed up by using the improved Henon sequence, Joseph sequence and the region of interest pixels are diffused by using the unified chaotic sequence to hide the sensitive information in the image, so as to achieve the purpose of private protection. Furthermore, the improved logistic sequence is used to hide the edge information of the target image to achieve the tradeoff between the secrecy of information and the complexity of encryption. A series of analyses are carried out including key space analysis, key sensitivity analysis, statistical analysis, information entropy analysis, analysis of the fixed-point obscuration analysis, quality analysis and image decryption for our encryption algorithm. Through experiments and comparisons, the proposed algorithm has good performance in encrypting image and coping with various invasions. The image encryption algorithm based on ROI has a good performance of security, moreover through the main encryption of ROI can effectively shorten the encryption time, so as to achieve the compromise of security and computational complexity. [ABSTRACT FROM AUTHOR]

Radish (Raphanus sativus L.) belongs to the family Brassicaceae. The Yunnan red radish variety contains fairly relatively large amounts of anthocyanins, making them important raw materials for producing edible red pigment. However, the genetic mechanism underlying this pigmentation has not been fully characterized. Herein, the radish inbred line YAAS-WR1 (white root-skin and white root-flesh) was crossed with the inbred line YAAS-RR1 (red root-skin and red root-flesh) to produce F1, F2, BC1P1, and BC1P2 populations. Genetic analyses revealed that the pigmented/non-pigmented (PiN) and purple/red (PR) traits were controlled by two genetic loci. The F2 population and the specific-locus amplified fragment sequencing (SLAF-seq) technique were used to construct a high-density genetic map (1230.16 cM), which contained 4032 markers distributed in nine linkage groups, with a mean distance between markers of 0.31 cM. Additionally, two QTL (QAC1 and QAC2) considerably affecting radish pigmentation were detected. A bioinformatics analysis of the QAC1 region identified 58 predicted protein-coding genes. Of these genes, RsF3'H, which is related to anthocyanin biosynthesis, was revealed as a likely candidate gene responsible for the PR trait. The results were further verified by analyzing gene structure and expression. Regarding QAC2, RsMYB1.3 was determined to be a likely candidate gene important for the PiN trait, with a 4-bp insertion in the first exon that introduced a premature termination codon in the YAAS-WR1 sequence. Assays demonstrated that RsMYB1.3 interacted with RsTT8 and activates RsTT8 and RsUFGT expression. These findings may help clarify the complex regulatory mechanism underlying radish anthocyanin synthesis. Furthermore, this study's results may be relevant for the molecular breeding of radish to improve the anthocyanin content and appearance of the taproots., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved.)