bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fade probability simulation analysis for aircraft platform wireless optical communication based on Hermite-Gaussian beam
Authors: Liu Xin , Zhang Yu , Jiang Dagang , Qin Kaiyu 
Published: April 2022

Abstract
Wireless optical communication technology can provide larger channel capacity for aircraft platforms which has great potentiality. In the application scenario of aircraft platform, the pointing error is inevitable. This study analyzes the fade probability of the link based on Hermite-Gaussian beam by using single-layer phase screen with pointing error simulation method and comparing with Gaussian beam. The higher order Hermite-Gaussian beam shows better link stability performance. Atmosphere turbulence has obvious effect on fade probability when the standard variance of pointing error is small, with the increase of standard variance of pointing error, the major influence factor for fade probability is pointing error rather than atmosphere turbulence.
Research and application of Civil Aircraft Function analysis Technology based on SysML Modeling
Authors: Zhang Jun , Li Piao 
Published: April 2022

Abstract
The design and development of civil aircraft is a systematic engineering project with high precision and high complexity. Traditional aircraft requirements are based on document transmission, which is not intuitive and logical, and are easy to miss requirements in different scenarios The Model-based function analysis is a method that can identify and define all elements of a certain function. In the process of function analysis, the relation between the function interfaces can be determined and the relative requirements can be obtained, which can consequently ensure the validity and integrity of aircraft functional requirements. The functional modeling analysis is carried out based on a SysML model in this paper, and the function is described from the perspective of structural level, behavioral level and activity level by using graphical and hierarchical expression. The internal logic of the function is analyzed in depth to obtain the functional requirements of the aircraft.
Fault Modeling and Simulation of Engine Driven Pump in Aircraft Hydraulic System
Authors: Han Bingjie , Niu Wei , Yan Tanbao 
Published: April 2022

Abstract
The structure of engine driven pump in aircraft hydraulic system is complex, its fault forms are diverse, and the fault transmission path is complex and multi factor coupling. In view of the above problems, based on the in-depth analysis of the working principle of the engine driven pump, the engine driven pump model is established, and the leakage fault injection mechanism of the friction pair is added. The relationship between the flow fluctuation characteristics of engine driven pump and the changes of pump spindle speed, swashplate inclination and pump outlet cavity volume are obtained through model simulation analysis. The mechanism of internal leakage fault of plunger pair, port pair and slipper pair are analyzed, the influence of leakage clearance parameters on key performance indexes such as pump pressure and flow are simulated, and the simulation test data of internal leakage fault of pump are obtained. The simulation results show that the inclination angle of swashplate and spindle speed are positively correlated with the output flow of the pump. The increase of pump outlet volume can effectively alleviate the pressure and flow fluctuation behind the pump. In addition, when the radial clearance of the plunger pair of this type of pump exceeds 0.2mm, the pump fault characteristics begin to appear. At the same time, the load change behind the pump will affect the characterization of the fault of internal leakage of the pump.
Method of civil aircraft emergency electrical power requirement analysis based on Systems Engineering
Authors: Zhao Zhiqiao , Zhang Jun 
Published: April 2022

Abstract
In this paper, the minimum function of civil aircraft power supply emergency is defined based on the model- based system engineering method and the principle of ensuring aircraft flight safety. Through functional architecture-logical architecture-physical architecture modeling, realize the mapping from minimum functions to minimum equipment. The system equipment that needs to work under the emergency electrical power supply of each aircraft system is sorted out from the forward direction, and the electricity requirements of the electrical equipment in different scenarios are analyzed statistically, and then the emergency electrical power requirements of the whole aircraft are obtained as the design input of the electrical power system.
A Novel Conflicting Evidence Combination Method for Fault Diagnosis of Civil Aircraft Electrical System
Authors: Jiang Xiaoting 
Published: April 2022

Abstract
D-S Evidence theory plays an important role in fault diagnosis of civil aircraft electrical system, but it is still difficult to deal with highly conflicting evidence. This paper introduces the idea of grey relational analysis, and proposes a new conflicting evidence combination method. The grey relational degree is used for calculating evidence’s credibility degree, by which conflicting evidence was processed before combination according to traditional D-S combination rule. One numerical example is employed and implemented. Through analysis and comparison of the combined results, of the existing alternatives, the proposed method shows better convergence and accuracy. It can effectively accelerate the fault diagnosis of the civil aircraft electrical system.
Study on the logical relationship between system safety and PMMEL project
Authors: Li Huan , Zheng You Shi 
Published: April 2022

Abstract
The Master Minimum Equipment List (MMEL) is an important technical manual for civil aircraft to meet release conditions and achieve release with failures, and it is also a key reference manual for airlines to develop the minimum equipment list. This paper firstly elaborates the relationship between PMMEL, MMEL and MEL, initially studies the system safety assessment process, and focuses on the logical relationship between system safety and PMMEL project development by detailing the role of system safety assessment FHA, FMEA and FTA in the development and analysis process of PMMEL during the aircraft development phase, to ensure the PMMEL work and The logical relationship between system safety and PMMEL project development is discussed to ensure the close integration between PMMEL work and civil aircraft development, to provide theoretical basis for manufacturers to fully consider the design of PMMEL in the development phase, and then to improve the capability of the developed aircraft with failure release.
Design and Actual Data Analysis of Chang’E-5 Landing Region Microwave Backscatter Coefficient
Authors: Niu Wenbo , Pan Lin , Li Shuanlao , Zhang Aijun , Dang Hongxing , Tan Xiaomin 
Published: April 2022

Abstract
Chang’E-3 landed at the north part of the Mare Imbrium on 14 December 2013, Chang’E-4 landed at South Pole’s Aitken Basin on 3 January 2019 and Chang’E-5 landed at Rümker region in northern Oceanus Procellarum on 1 December 2020. The microwave range and velocity sensor (MRVS) on the lander provided the range and velocity information relative to the lunar surface during the powered descent phase, ensuring landing softly. In this paper, we use the lunar surface backscatter coefficient of Ka-band which was analyzed from the telemetry of MRVS equipped on Chang’E-3 and Chang’E-4, as for the important design basis of Chang’E-5 MRVS; at the same time, actual data is analyzed from the telemetry of Chang’E-5 sensor, and the accumulated analysis of lunar surface backscatter coefficient as the important reference will be used in the future MRVS design and lunar detection.
A study on development of intelligent ground-based air defense radar under the background of modern war
Authors: Yang PENG 
Published: April 2022

Abstract
The new characteristics of modern war put forward new requirements for intelligent ground-based air defense radar. This paper refines the new characteristics of modern war from the aspects of combat object, combat environment and combat style; Based on this, from the perspective of adapting to modern war, this paper analyzes and summarizes the intelligent development of ground-based air defense radar in intelligent perception, resource allocation, man-radar integration and so on, which plays a guiding role in the theoretical research and engineering realization of ground-based air defense radar technology. In addition, the combat effectiveness of intelligent and traditional ground air defense radar is evaluated by analytic hierarchy process, which can be used as a reference for subsequent research.
The Research on Evasion Strategy of Unpowered Aircraft Based on Deep Reinforcement Learning
Authors: Chen Keqin , Lei Jianchang , Li Bin 
Published: April 2022

Abstract
For the pursuit-evasion (PE) game, this paper proposes an evasion strategy with coordinated control of angle of attack, bank angle and body morphing control using deep reinforcement learning. Considering the evasion and ballistic regression of the aircraft, the specified miss distance (SMD) and residual energy are used as the optimization objectives, to acquire the optimal control strategy against the encounter with pursuer in the terminal guidance phase. For the problem of sparse rewards, reward reshaping cannot be performed for this problem, we modify DQN algorithm with the mechanism of Monte-Carlo reinforcement learning to improve the sampling efficiency and realize the end-to-end learning. Finally, the linear analytical solution of the problem based on SMD is analyzed theoretically. With it, the strategy obtained by reinforcement learning is compared and explained.
Influence of atmospheric density and area-to-mass errors on orbit prediction accuracy
Authors: Hao Yimeng , Zhang Shuo , Zheng Xiaoyu , Qu Jinye 
Published: April 2022

Abstract
Due to the fact that the space is becoming increasingly congested, there is a high requirement for the orbit prediction accuracy of space targets to support collision warning tasks. This is especially true for space debris with high area-to-mass ratio and low orbit altitude. This paper focuses on the along-track position error caused by the atmospheric density error and area-to-mass ratio error for targets with near-circular orbit in the orbit prediction. We derive a semi-analytical expression to describe the along-track position error, and the expression’s validity is evaluated by a goodness-of-fit index compared with the simulated “true” along-track position error. The simulation is based on Encke’s special perturbation method, in which the drag error is treated as a perturbation. The drag error is modeled by the difference between the JB2008 and MISIS density model and the sinusoidal oscillation error model concerning the inexact area-to-mass ratio. Furthermore, targets with various orbit altitudes ranging from 300km to 800km are selected to investigate whether the along-track position error can meet the collision warning requirements.
Selection and Realization of Structural Damage Detection Waveform based on Lamb Wave
Authors: Wang Yongzhi , Wu Hongjiao 
Published: April 2022

Abstract
Aiming at the problem of waveform fixing and unsatisfactory detection effect in structural damage detection based on Lamb wave, a waveform selection method based on the Kalman filter was proposed to obtain structural damage information. Firstly, the waveform selection model is constructed by combining the propagation characteristics of Lamb wave and the Kalman filter. Then the finite element simulation is carried out, the propagation of Lamb wave was simulated by ANSYS, and the optimal waveform was determined by joint calculation with MATLAB. Finally, experimental verification is carried out on the basis of finite element simulation to further verify the waveform selection method based on the Kalman filter. Through simulation and experimental study, it is verified that the waveform selection method based on the Kalman filter can improve the damage location accuracy of structures.
A fusion CNN driven by images and vibration signals for fault diagnosis of gearbox
Authors: Zhou Qiting , Mao Gang , Li Yongbo 
Published: April 2022

Abstract
Gearbox diagnosis is critical for avoiding catastrophic failure and minimizing financial damages. Aiming at the problem that the vibration-based fault diagnosis methods cannot effectively identify the non-structural failure mode and the diagnosis model based on the infrared thermal image is not robust enough, a fusion fault diagnosis method for gearboxes using vibration signals and infrared images is proposed. By fusing these two kinds of heterogeneous data, the proposed method can identify both structural and unstructured health states while maintaining high robustness. In addition, CNN has powerful image processing capabilities, which can directly process two-dimensional infrared images and achieve high accuracy. Finally, a gearbox experiment is carried out to test the performance of our method. The results suggest that the proposed fusion CNN can obtain the highest accuracy compared with some methods based on single signals, shallow learning methods SVM and deep unsupervised learning methods SAE.
Forest fire effects on stream water quality at continental scales: a meta-analysis
Authors: Hampton Tyler B , Lin Simon , Basu Nandita B 
Published: April 2022

Abstract
Forested watersheds supply over two thirds of the world’s drinking water. The last decade has seen an increase in the frequency and intensity of wildfires that is threatening these source watersheds, and necessitating more expensive water treatment to address degrading water quality. Given increasing wildfire frequency in a changing climate, it is important to understand the magnitude of water quality impacts following fire. Here, we conducted a meta-analysis to explore post-fire changes in the concentrations of nitrogen (N) and phosphorus (P) species, dissolved organic carbon, and total suspended sediments in 121 sites around the world. Changes were documented over each study’s respective duration, which for 90% of sites was five years or fewer. We find concurrent increases in C, N and P species, highlighting a tight coupling between biogeochemical cycles in post-fire landscapes. We find that fire alters N and P speciation, with median increases of 40%–60% in the proportion of soluble inorganic N and P relative to total N and P. We also found that fire decreases C:N and C:P ratios, with median decreases ranging from 60% to 70%. Finally we observe a ‘hockey stick’-like response in changes to the concentration distribution, where increases in the highest concentration ranges are much greater than increases at lower concentrations. Our study documents strong heterogeneity in responses of water quality to wildfire that have been unreported so far in the literature.
On the electron sheath theory and its applications in plasma–surface interactions
Authors: SUN Guangyu , ZHANG Shu , SUN Anbang , ZHANG Guanjun 
Published: April 2022

Abstract
In this work, an improved understanding of electron sheath theory is provided using both fluid and kinetic approaches while elaborating on their implications for plasma–surface interactions. A fluid model is proposed considering the electron presheath structure, avoiding the singularity in electron sheath Child–Langmuir law which overestimates the sheath potential. Subsequently, a kinetic model of electron sheath is established, showing considerably different sheath profiles in respect to the fluid model due to non-Maxwellian electron velocity distribution function and finite ion temperature. The kinetic model is then further generalized and involves a more realistic truncated ion velocity distribution function. It is demonstrated that such a distribution function yields a super-thermal electron sheath whose entering velocity at the sheath edge is greater than the Bohm criterion prediction. Furthermore, an attempt is made to describe the electron presheath–sheath coupling within the kinetic framework, showing a necessary compromise between a realistic sheath entrance and the inclusion of kinetic effects. Finally, the secondary electron emissions induced by sheath-accelerated plasma electrons in an electron sheath are analysed and the influence of backscattering is discussed.
ExsgRNA: reduce off-target efficiency by on-target mismatched sgRNA
Authors: Hu Wei-Xin , Rong Yu , Guo Yan , Jiang Feng , Tian Wen , Chen Hao , Dong Shan-Shan , Yang Tie-Lin 
Published: April 2022

Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing technology has been widely used to facilitate efficient genome editing. Current popular sgRNA design tools only consider the sgRNA perfectly matched to the target site and provide the results without any on-target mismatch. We suppose taking on-target gRNA-DNA mismatches into consideration might provide better sgRNA with similar binding activity and reduced off-target sites. Here, we trained a seq2seq-attention model with feedback-loop architecture, to automatically generate sgRNAs with on-target mismatches. Dual-luciferase reporter experiment showed that multiple sgRNAs with three mismatches could achieve the 80% of the relative activity of the perfect matched sgRNA. Meanwhile, it could reduce the number of off-target sites using sgRNAs with on-target mismatches. Finally, we provided a freely accessible web server sgRNA design tool named ExsgRNA. Users could submit their target sequence to this server and get optimal sgRNAs with less off-targets and similar on-target activity compared with the perfect-matched sgRNA.
ATHENA: analysis of tumor heterogeneity from spatial omics measurements
Authors: Martinelli Adriano Luca , Rapsomaniki Maria Anna 
Published: April 2022

AbstractSummaryTumor heterogeneity has emerged as a fundamental property of most human cancers, with broad implications for diagnosis and treatment. Recently, spatial omics have enabled spatial tumor profiling, however computational resources that exploit the measurements to quantify tumor heterogeneity in a spatially aware manner are largely missing. We present ATHENA (Analysis of Tumor HEterogeNeity from spAtial omics measurements), a computational framework that facilitates the visualization, processing and analysis of tumor heterogeneity from spatial omics measurements. ATHENA uses graph representations of tumors and bundles together a large collection of established and novel heterogeneity scores that quantify different aspects of the complexity of tumor ecosystems.Availability and implementationATHENA is available as a Python package under an open-source license at: https://github.com/AI4SCR/ATHENA. Detailed documentation and step-by-step tutorials with example datasets are also available at: https://ai4scr.github.io/ATHENA/. The data presented in this article are publicly available on Figshare at https://figshare.com/articles/dataset/zurich_pkl/19617642/2.Supplementary informationSupplementary data are available at Bioinformatics online.
Comparison of automated digital Peer Assessment Rating compared with measurements performed by orthodontists, dental students, and assistants using plaster, additive manufactured, and digital models
Authors: Hannebauer Anika , Wesemann Christian , Bartzela Theodosia , Bister Dirk , Bumann Axel 
Published: April 2022

Summary

Background
There are little scientific data on fully automated Peer Assessment Rating (PAR); this study compares a number of PAR scoring methods to assess their reliability.

Objectives
This investigation evaluated PAR scores of plaster, 3D printed, and virtual digital models scored by specialist orthodontists, dental auxiliaries, undergraduate dental students,and using a fully automated method.

Materials and methods
Twelve calibrated assessors determined the PAR score of a typodont and this score was used as the gold standard. Measurements derived from a plaster model, a 3D printed model, and a digital model, were compared. A total of 120 practitioners (specialist orthodontists, dental auxiliaries, and undergraduate dental students, n = 40 each) scored the models (n = 10) per group. The digital models were scored twice, using OnyxCeph (OnyxCeph) and OrthoAnalyzer (3Shape). The fully automated PAR scoring was performed with Model+ (Carestream Dental).

Results
Neither type of model (P = 0.077), practitioner category (P = 0.332), nor interaction between the two (P = 0.728) showed a statistically significant effect on PAR scoring. The mean PAR score and standard deviation were comparable for all models and groups except the automated group, where the standard deviation was the smallest (SD = 0). Overall, the greatest variation was observed for weighted overjet and contact point displacements.

Conclusions
PAR scoring using plaster, 3D printed, and digital study models by orthodontists, dental auxiliaries, dental students, and a fully automated method produced very similar results and can hence be considered equivalent. Automated measurements improve repeatability compared with all groups of practitioners, but this did not reach the significance level.
Joint association of socioeconomic circumstances and minor mental health problems with antidepressant medication
Authors: Salonsalmi Aino , Mauramo Elina , Rahkonen Ossi , Pietiläinen Olli , Lahelma Eero 
Published: April 2022

Abstract

Background
Disadvantageous socioeconomic circumstances and minor mental health problems have both been associated with mental disorders, such as depression, but their joint contribution remains unknown.

Methods
The Helsinki Health Study baseline survey (2000–02) of 40- to 60-year-old employees was linked with antidepressant medication data from registers of the Social Insurance Institution of Finland. The analyses were made using logistic regression with first prescribed antidepressant medication purchase during a 10-year follow-up as the outcome. Minor mental health problems were measured by the emotional well-being scale of the RAND-36. Odds ratios were calculated for joint association of the lowest quartile of the emotional well-being scale of the RAND-36 and socioeconomic circumstances. Childhood (parental education and childhood economic difficulties), conventional (education, occupational class and income) and material (housing tenure and current economic difficulties) socioeconomic circumstances were examined. This study included 5450 participants.

Results
Minor mental health problems dominated the joint associations. Minor mental health problems were associated with antidepressant medication irrespective of socioeconomic circumstances whereas only low income, current economic difficulties and living in rented housing showed an association without minor mental health problems at baseline. Marital status, working conditions and BMI and health behaviours had only minimal contributions to the associations.

Conclusions
Minor mental health problems were consistently and strongly associated with antidepressant medication and dominated the joint associations with socioeconomic circumstances. Paying attention to minor mental health problems might help prevent mental disorders such as depression.