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In the current research on the fatigue state of controllers using radiotelephony communication, most of them only consider the changes of voice in the time domain or frequency domain, while ignore that fatigue will affect the time domain and frequency domain at the same time. The voice of radiotelephony communication in the three fatigue states is converted into speech spectrum images that can reflect the characteristics of both the time domain and frequency domain, and the grayscale co-existence matrix is used to extract the typical feature parameters in four dimensions. The changes of the characteristic parameters of the controllers in different states are compared, and the controller fatigue detection model is constructed to detect the input features. The results show that the detection accuracy of using the spectrogram features combined with the traditional features as the input features is the highest(95.49%), which is 4% higher than that of the traditional features alone. The change of controllers fatigue state can intuitively reflected on the spectrogram and haves an impact on its eigenvalues, and the better detection results can be obtained by using this influence to detect the controllers fatigue state.

In this paper, a data-driven framework aimed at investigating how weather factors affect the spatio-temporal patterns of air traffic flow in the terminal maneuvering area (TMA) is presented. The framework mainly consists of three core modules, namely, trajectory structure characterization, flow pattern recognition, and association rule mining. To fully characterize trajectory structure, abnormal trajectories and typical operations are sequentially extracted based on a deep autoencoder network with two specially designed loss functions. Then, using these extracted elements as basic components to further construct and cluster per-hour-level descriptions of airspace structure, the spatio-temporal patterns of air traffic flow can be recognized. Finally, the association rule mining technique is applied to find sets of weather factors that often appear together with each flow pattern. Experimental analysis is demonstrated on two months of arrival flight trajectories at Hong Kong International Airport (HKIA). The results clearly show that the proposed framework effectively captures spatial anomalies, fine-grained trajectory structures, and representative flow patterns. More importantly, it also reveals that those flow patterns with non-conforming behaviors result from complex interactions of various weather factors. The findings provide valuable insights into the causal relationships between weather factors and changes in flow patterns, greatly enhancing the situational awareness of TMA. [ABSTRACT FROM AUTHOR]

To adapt to the intelligent management of traffic flow in modern aviation, this study improves the algorithm according to the data exercise method and establishes the mathematical model and vector model of intelligent motion coordinates. Moreover, according to the simulation test method, this study analyzes the six-degree-of-freedom equation of motion in the coordinate system of the civil aviation aircraft and uses the simulation method to regard the civil aviation as a rigid body with a certain mass and mass distribution. In addition, this study builds an intelligent model based on the demand analysis, and according to the actual demand, this study combines the simulation method to analyze the structure of the intelligent management model of air traffic flow. Finally, this study uses the experimental analysis method to verify the effect of the model proposed in this study and combines the experimental research to verify that the model proposed in this study has a certain effect., Author(s): Junhao Liu (corresponding author) [1]; Qing Cheng [1]; Yuanji Wang [1]; Changqi Yang [1]; Rui Zhou [1]; Xinping Zhu [1]; Di Yao [1]; Junjie Zhou [1]; Yaqian Du [1]; [...]

A series of experiments were performed aiming at controlling milling force-induced surface errors in the robot-assisted milling process, for the sub-area of the multi-stiffener reinforced inner wall of complex cylindrical thin-walled casting parts, to investigate the relationship between surface errors, milling forces, and robot-assisted milling parameters. Firstly, based on the design of experiments (DoE) method, milling forces and surface errors were investigated based on a series of experiments with different groups of milling parameters. Secondly, the modeling of milling forces, surface errors, and milling parameters was realized by means of response surface methodology (RSM), then the parametric expression was obtained of the robot-assisted milling process. Finally, the parameters of the milling process toward the surface error were obtained based on an evolutionary algorithm. The results show that the surface errors are different for the different milling styles of down milling and up milling. In up milling processes, the surface errors are positive, and the actual material removal amounts are generally higher than the nominal ones, while negative in down milling processes. The surface errors induced by milling forces can be effectively controlled and reduced using process optimization in the robot-assisted milling process, while maintaining relatively high milling forces and high machining efficiency. This provides theoretical support for industry applications. [ABSTRACT FROM AUTHOR]

This paper studies the production scheduling problem in an assembly manufacturing system with uncertain processing time and random machine breakdown. The objectives of minimizing makespan and the performance deviation of the actual schedule from the baseline schedule are simultaneously considered. Specifically, a boosting radial basis function network constructed using the data generated by Monte Carlo method, is used as the surrogate model to approximate the performance deviation. After that, a modified master-apprentice evolutionary algorithm (MAE) is developed for robust scheduling. In the design of MAE, we employ an extended adjacency matrix of subassemblies to cope with the sequential constraints of operations in AJSSP. Based on this, effective neighbourhood structures and distance metric of solutions are designed for tabu search and path relinking operators to generate feasible schedules. To evaluate the effectiveness of the proposed method, a series of computational experiments are conducted. The results indicate that, compared with several commonly used algorithms, the suggested method shows good performance in dealing with AJSSP under uncertainty. [ABSTRACT FROM AUTHOR]

Studying granitoids can provide important knowledge on the composition of continental crust and the geodynamic processes of continental growth. Nevertheless, the mechanisms of granitoids formation during continental collision remain uncertain. In this paper, we present new zircon U–Pb–Hf isotope and whole‐rock Sr–Nd isotope compositions, and major‐ and trace‐element data for granitoids from the Chacangka area of the central Lhasa Terrane, southern Tibet. The Chacangka quartz monzonites crystallized at ca. 61 Ma, whereas the monzonites and granites were emplaced at ca. 51 Ma. The quartz monzonites are peraluminous and have high 87Sr/86Sri ratios (0.7129–0.7131), and their low εNd(t) (−7.65 to −7.10) and zircon εHf(t) (−9.3 to −7.5) values are more depleted than those of ancient crustal basement beneath the central Lhasa Terrane, which suggests that they originated from a mixed source of juvenile and ancient lower crust. Compared with the quartz monzonites, the monzonites have much higher contents of MgO (2.34–3.62 wt%) and values of Mg# (42.3–46.3) and zircon εHf(t) (−6.9 to 1.9) and show more depleted Sr–Nd isotopes, indicating that more juvenile materials were involved in their source. The granites have Sr–Nd isotope compositions that are similar to those of the coeval monzonites but have higher SiO2 contents, lower CaO and MgO contents, and lower values of Mg#, suggesting that they were differentiates of the monzonites. The elemental and isotopic compositions of the Chacangka granitoids exhibit a marked transformation from 61 to 51 Ma, probably indicating breakoff of the Neo‐Tethyan oceanic slab. The Neo‐Tethyan slab breakoff not only induced the upwelling of deep material and eruption of magma but also caused re‐melting and destruction of ancient crustal basement of the central Lhasa Terrane. [ABSTRACT FROM AUTHOR]

Southern Tibet is a key region for investigating the magmatism that occurredduring the collision between India and Asia. The break‐off of the Neo‐Tethyan slab, after the onset of continental collision at ca. 65–60 Ma, affected the lithospheric thermal regime and led to a series of magmatic and tectonic events. Many magmatic rocks generated by slab break‐off have been reported in southern Tibet; however, which of these record the initial slab break‐off (i.e., slab tearing) is still an open question. The Lianxiang gabbros, which intrude an ophiolite in central‐southern Tibet, provide an ideal opportunity to investigate the footprint of the initial slab break‐off. Zircon U–Pb ages show that the Lianxiang gabbros crystallized at 57–53 Ma, coeval with other mafic dikes in southern Tibet. The Lianxiang gabbros are characterized by high Na2O (2.13–5.42 wt%), Al2O3 (13.86–17.13 wt%), and V (188–346 ppm) contents and moderate Mg# (40.8–65.9). The gabbrosare slightly depleted in light rare earth elements [LREE; (La/Yb)N = 0.45–0.76], similar to normal mid‐ocean ridge basalt (N‐MORB). They also have low 87Sr/86Sri ratios (0.703538–0.705698) and high εNd(t) values (9.49–10.68), indicating that they were derived mainly from a shallow asthenospheric mantle source. Combining our results with data from other magmatism at ~57 Ma in the southern Lhasa Terrane, we propose that the N‐MORB‐type rocks reflect the tearing of the Neo‐Tethyan slab. The process of slab break‐off differed between western and eastern southern Tibet, possibly as a result of different lithospheric structures and compositions. [ABSTRACT FROM AUTHOR]

Accurate simulation about the grinding temperature distribution helps to decrease the thermal damage and microcracks during the grinding process. In this article, the grinding heat transfer process of form grinding was analyzed and a temperature distribution model was derived in form grinding of 9Mn2V thread gauge. Considering the characteristics of form grinding, the temperature rise of the intersection region can be affected by two kinds of heat sources, and the impact between the two heat sources has been investigated. Also, the influence of the grinding depth on the temperature rise was analyzed. Depending on the analysis, an improved heat partition model has been derived, which is based on single-grain energy partition model. A series of experiments were carried out to investigate the grinding performance of 9Mn2V. The grinding force was obtained, the specific grinding energy was discussed, and the experimental temperature was measured by infrared imager. It is shown that the experiment results correspond well to the theoretical temperature calculated by the prediction model. This temperature model can be used to optimize the grinding conditions and the critical depth in form grinding of 9Mn2V thread gauge. [ABSTRACT FROM AUTHOR]