bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and Verification of CBTC system security Communication protocol based on time Automaton
Authors: Zhao Yan , He Tao , Li Qiang
Published: August 2020

With the rapid growth of population and economy, passengers’ demand for urban rail transit is increasing, and it is difficult for single-line rail transit to meet passengers’ demand for rapid transfer. Therefore, the interconnection between urban rail lines has been the focus of development in recent years. Therefore, the secure communication between various devices is a very important link in the interconnection test. Chongqing Metro Line 10 is the first metro line to realize the interconnection based on the secure communication protocol, in which the specific parameter setting in the secure communication protocol is specified, so the method is needed to verify the security of the protocol. In this paper, the time automaton theory is adopted to carry out the corresponding modeling work for the two key safety key contents of the safety communication protocol in the railway, namely the protocol chain building process and the protocol retransmission process, and verify its security and timeliness. Finally, a test platform is built to test the communication function between the systems.
Study on Critical Load for Multistage Hydraulic Cylinder
Authors: Xie Fang , Zhang Peng , Liu Dejun
Published: August 2020

To prevent the appearance of buckling failure when the multistage hydraulic cylinder works, the finite element of compression rod simplified model instead of multistage hydraulic cylinder is established based on the importance of engineering safety operation. The linear and nonlinear buckling analysis for compression rod can be realized by the finite element analysis software called ABAQUS. Meanwhile, the value of critical load for compression rod can be calculated and compared from two aspects of linearity and nonlinearity. The results indicate that the value got from nonlinear buckling analysis is more conservative than linear buckling analysis and the value of critical load is proportional to the cross section area.
Research and development of fire extinguishing equipment for passenger compartment
Authors: Zhang Tianhao , Xu Shuquan , Liu Fujia
Published: August 2020

In view of the problems of the passenger vehicle, such as single fire-fighting method, low degree of automation, long response time, poor fire extinguishing effect. In this paper, the high-pressure water mist fire extinguishing equipment for passenger compartment was researched and developed. The defects and characteristics of fire prevention and control of passenger vehicle were analyzed firstly, and on this basis, the functional requirements and selection schemes of fire prevention and control equipment were proposed. Then, the selection scheme was used for trial production of equipment, and the fire extinguishing performance test was carried out to verify the effectiveness of the equipment. The test results showed that the equipment had good fire extinguishing effect. After the equipment was activated, the fire in the passenger compartment was significantly suppressed. After 3 s of start-up, the open fire was almost extinguished. After 10 s of start-up, the toxic black smoke almost disappeared and the average temperature in the passenger compartment dropped to 60°C.
Optimization of crankshaft main bearing lubrication performance considering bearing profiles
Authors: Du Qingchuan , Cheng Ying , Ren Peirong , Zhang Zhongwei
Published: August 2020

It is the aim of this work to reduce friction power loss of main bearings by optimization. To this purpose, elastohydrodynamic (EHD) model is used for EHD calculations for different main bearings. BP neural network is implemented to establish the approximation model for bearings. Then, multi-objective optimization of bearings using genetic algorithm is formulated and conducted. It is found that a more compliant bearing profile can provide hydrodynamic lift during film lubrication while bearing profiles have more significant impact on lubrication performance in comparison to other key parameters. The results of the BP network model using the genetic algorithm agree closely with the calculated value based on EHD-MBD model. The presented approach allows reliably to conduct the optimization of bearings. After optimization, the friction power loss is significantly reduced while the minimum oil film thickness increases and the total pressure drops.
Coupling Effect Analysis of Airborne Cable under High Intensity Radiation Field Environment
Authors: Sun Fei , Jia Yun-feng , Duan Bo
Published: August 2020

With the improvement of equipment informatization, the importance of electromagnetic compatibility and the adaptability of complex electromagnetic environment has become increasingly prominent, and the influence of high intensity radiation fields (HIRF) on aircraft electronic equipment has become more and more significant, which has seriously threatened flight safety. In order to examine the coupling characteristics of airborne cables under HIRF irradiation, this paper used FEKO electromagnetic simulation software for analyse and study. The influence of different radiation fields, cable types, installed positions and gap structure on the simulation results was analyzed. And coupling patterns of airborne cables in the HIRF environment were obtained. The conclusions obtained in this paper have a definite guiding significance of the research on airborne cable protection for HIRF.
Design of digital detection circuit for signal of helium optical pump magnetometer Summary
Authors: Chen Long , Ping ZengLiang
Published: August 2020

Magnetic field measurement technology is an important method to study physical phenomena related to magnetic field. Magnetic field measurement, especially weak magnetic field measurement, often plays a vital role and has important theoretical significance and engineering value for the research of high-performance magnetic field measurement instruments. The helium optical pump magnetometer is a high-precision magnetic measuring device that uses optical pumping and magnetic resonance to realize magnetic field measurement based on the principle of optical magnetic resonance. It has the advantages of low noise, wide measurement range, and low temperature working environment. It has significant advantages in the field of weak magnetic field measurement and can be widely used in scientific research, national defense construction, industrial production, daily life and other fields. The traditional detection circuit is based on a voltage-controlled oscillator as the core and an analog circuit-based detection system. The modulation signal is used for magnetic field detection. The detection speed is slow, and the modulated signal will superimpose an interfering magnetic field on the probe, affecting the measurement result. This paper designs a digital detection system with DDS technology as the core, which greatly improves the speed of detecting the magnetic field. A new swingswing frequency method is used to avoid the interference of the modulation coil, and a breakthrough in detection speed is achieved, reaching a sampling frequency of 20Hz. To meet the requirements of a system that requires continuous measurement at a faster rate.
A Novel Foreign Object Detection Algorithm Based on GMM and K-Means for Power Transmission Line Inspection
Authors: Yao Nan , Zhu Lvfu
Published: August 2020

The detection of foreign objects on transmission lines is an important research content of intelligent inspection in smart grid. The foreign objects on the transmission line tower will cause adverse effects on the transmission line and other equipment, and even endanger the safe operation of the power grid. In order to accurately identify foreign objects on power transmission lines, this paper proposes an unsupervised foreign object detection algorithm based on GMM (Gaussian Mixture Model) and k-means. Firstly, K-means is used for clustering, and then GMM is used for clustering. Finally, the foreign objects on the power transmission line are identified according to the clustering results. Experimental results show that the proposed algorithm has a high recognition rate. In addition, the more samples, the higher the recognition accuracy.
A Cross Correlation based Back-Projection Imaging Method for Through-Wall Imaging
Authors: Cai Jiliang , Peng Peng , Zeng Huiyong , Wang Shiqiang
Published: August 2020

A back-projection (BP) algorithm based on cross-correlation (CBP), which is both fast and good at suppressing artifacts, is adopted here for through wall imaging (TWI). Firstly, by “moving” the wall to the image point, the three layer TWI modal is equivalent to the two layer TWI modal. By doing so, only half of the reflection points are needed to be calculated; secondly, to further reduce the calculation time, on the one hand, the symmetric-invariant property as well as the shift-invariant property of the ray propagation is used to calculate the look-up table, on the other hand, the delay-multiply-sum equation in CBP is rewrite into a new form with less addition and multiply computation. Simulation results show the superiority of the proposed CBP algorithm both in operation speed and artifacts suppression.
A Flame Detection Method Based on Fusion Feature and SVM for Substation Inspection
Authors: Deng Jieqing , Wei Chao , Chen Guang , Xu Liang , Zhu Bo
Published: August 2020

For the safety inspection of substation, this paper proposes a flame image detection method based on the combination of fusion feature and support vector machine (SVM). Firstly, the suspected flame area is detected by motion detection and flame color model. Then, four features of B-channel color variation coefficient, roughness, flicker frequency and flame area change rate are extracted. Finally, four features are sent to SVM to learn the flame classifier and used in video flame detection. The experimental results show that the proposed method can effectively identify the flame.
Research on the influencing factors of consumer satisfaction in agricultural e-commerce supply chain
Authors: Chunshang Wu
Published: August 2020

In recent years, e-commerce for agricultural products has developed rapidly, but the overall scale of e-commerce for agricultural products is still small due to consumers’ low satisfaction with the overall supply chain of e-commerce for agricultural products.So, it is very important to find out the key factors that affect the satisfaction of agricultural e-commerce supply chain and improve consumer satisfaction. Through the construction of factor analysis model, this paper analyzes the factors that affect the supply chain of e-commerce of agricultural products, and finds that the quality of agricultural products is the most influential factor, followed by after-sales service, e-commerce platform, and the price factor is the least. Therefore, in order to improve consumer satisfaction, we should focus on improving the quality of agricultural products, after-sales services, e-commerce platform convenience.
Explore the research fronts of cross-border E-commerce
Authors: Pan Chung-Lien , Niu Jiangrong , Luo Ting , Chen Zixuan
Published: August 2020

Cross border e-commerce as a trend of development in recent years has been widely concerned. The policies issued by the government and the global economic development situation have also been promoting the development of cross-border e-commerce. It is not difficult to see that cross-border e-commerce is in full swing at home and abroad, showing a high-speed development trend. In this context, in order to systematically review the relevant literature in this field, based on the scientific econometric analysis of 431 articles published from 1995 to 2020 collected from the WOS database, the author analyzes the development of cross-border e-commerce by using this database, summarizes the annual trend since 1995, publishing institutions and publications, and analyzes the author’s keywords Visual integrated presentation. The purpose of this paper is to provide some reference points for researchers, managers and industry professionals.
Research on excitation system of synchronous generator
Authors: Jiang Dawei , Qian Xinyu , Yu Longbin , Wang Guanyu , Zhao Zijian , Cheng Xiang , Li Jing
Published: August 2020

With the rapid development of power grid, large capacity units are continuously put into operation, which makes the small interference. This paper analyzes the influence of different regulation modes of AC exciter excitation system on the performance of generator excitation control system, demonstrates that PID excitation regulation can effectively improve the quality of excitation control, and simulation test is an effective measure to adjust the parameters of excitation system.
Study on Propagation Characteristics of Obliquely Incident Terahertz Wave in Non-Magnetized Plasma
Authors: Tao Zheng , Pan Ziyi , Ye Qiong
Published: August 2020

A transmission model of THz wave in non-uniform and magnetized plasma is established. Based on the analysis of transmission characteristics in Gaussian and uniform plasma environments, theoretical simulations are performed using the continuity conditions of the electric and magnetic fields at the boundary of each layer. The effects of collision frequency, electron density and incident angle on the attenuation of THz wave energy are mainly discussed. The attenuation of the THz wave by the collision frequency does not change monotonously, and the optimal frequency needs to be selected according to the actual situation. THz wave attenuation increases with increase of electron density. And the THz wave attenuation decreases with the increase of the incident angle. Vertical incidence can be used as a means to alleviate the “communication blackout”. The conclusions of this paper provide a good theoretical basis and relevant parameter references for alleviating the “communication blackout” problem.
An efficient attribute-based authentication scheme with multiple authorities in public cloud
Authors: Liu Xin , Guo Man , Zhang Bin , Li Xuzhou
Published: August 2020

Currently, attribute-based authentication provides a feasible solution for fine-grained access control in cloud environment. However, the existing schemes can not solve the following problems at the same time, that is, how to ensure that the computation cost of the client does not depend on the size of underlying access structure, and how to introduce distributed authorities to manage and maintain the attribute universe. To solve the above problems, an efficient multi-authority attribute-based authentication scheme is proposed. The new scheme uses the technique of distributed attribute-based encryption to realize the access control of anonymous users, and reduces users’ computation burden by optimizing the standard implementation zero-knowledge proof and outsourcing users’ computing tasks in the authentication stage. Under the new definition of security, it can be proved that the new scheme is secure and satisfies many attractive properties, such as introducing distributed authorities, supporting outsourcing computation, satisfying attribute anonymity.
An online/offline distributed attribute-based authentication scheme
Authors: Liu Xin , Guo Man , Li Xuzhou , Zhang Bin
Published: August 2020

Attribute-based authentication is an effective cryptography mechanism, which makes it possible for service providers to implement fine-grained access control on cloud resources. Although many attribute-based authentication schemes have been proposed, most of them only support single attribute authority and users have to perform a large amount of computation in the authentication phase. By extending the ciphertext policy attribute-based encryption scheme of Rouselakis et al, a distributed attribute-based authentication scheme was designed. The feature of the new scheme is to optimize the online computation efficiency of both service providers and users, i.e., by introducing the technique of online/offline attribute-based encryption, the online computational burden of semi trusted servers is greatly reduced. On the other hand, by introducing outsourcing decryption, users’ computation in the authentication stage is independent of the size of underlying access structures. Compared with previous schemes, the new scheme satisfies several ideal properties, that is, introducing distributed authorities, supporting outsourcing computation, satisfying anonymity and unlinkability, and so on.
Research on Antenna Selection of Projectile-carried Communication Jammer
Authors: Zhang Jie , Ma Wenjun , Zhang Xiaolei
Published: August 2020

Focusing on the antenna selection of the projectile-carried communication jammer, this paper analyzed the requirements of the projectile-carried environment on the transmitting antenna from five aspects: antenna type, number of antenna parameters, signal propagation path, communication distance of the transceiver, calculation complexity of the radio’s sensitivity. The results show that in the process of designing and developing the projectile-carried communication jammer, it is suitable to select small whip antenna for projectile-carried communication jamming antenna.
Security Analysis of Public Security Terminal Network and Its Peripheral Equipment
Authors: Wu Yuqiang , Wu Yubao , Yang Wengan
Published: August 2020

As a major focus of global Internet security, peripheral equipment security is getting more and more attention. Due to the serious asymmetry between the high access level and the low protection level of the public security network and its peripheral equipment, it is very easy to be attacked by hackers. This paper briefly describes the Internet of things access technology, introduces the public security terminal network interconnection access mode and part of the network topology. Based on the preliminary analysis of the security of the software and hardware of the public security terminal network and its edge equipment, this paper analyzes the security of the public security terminal network and its peripheral equipment for the subsequent security design, to ensure the reliability of the public security terminal network and its peripheral equipment, and to strengthen the network security of the public security terminal network.
Analysis and Optimization of a Pulse Repetition Frequency for Along-Track Distributed Multiple-Input Multiple-Output Synthetic Aperture Radar
Authors: Pengcheng Li , Zaoyu Sun , Feng He , Yongsheng Zhang
Published: August 2020

A distributed multiple-input multiple-output synthetic aperture radar (MIMO-SAR) system combines azimuth multi-channel and digital beamforming technologies to produce data with a high-resolution azimuth and wide swath. The MIMO-SAR system uses a tight along-track formation, and the spacing between its satellites is typically 100 m. The space sampling characteristic is sensitive to changes in pulse repetition frequency (PRF). This paper presents a method for optimizing the PRF of a distributed MIMO-SAR system based on the performance of the latter. The optimized PRF adapts well to variations in satellite spacing. These results show that PRF optimization can effectively improve the performance of the distributed MIMO-SAR system.
The intrapulse beamsteering radar based on OFDM Chirp signals
Authors: Wang Shenjing , He Feng , Sun Zaoyu , Li Pengcheng , Dong Zhen
Published: August 2020

The OFDM (Orthogonal Frequency Division Multiplexing) technique is widely used in communication field due to the great waveform diversity and anti-fading ability of OFDM signals. Because of the similarity of radar system and communication system, The OFDM radar has gradually emerged as a new system radar in recent years. At the same time, Intrapulse beamsteering system is a kind of multi-dimensional waveform encoding, which can improve the transmitting efficiency and multi-mission performance of radar. So, this paper proposes a new radar operating mode with the combination of the OFDM chirp signals and the intrapulse beamsteering in elevation, that is the combination of waveform orthogonality and beam orthogonality, we can also call it “double insurance”, which can greatly improve the emission efficiency and the system performance. Especially the interference suppression and the robustness to terrain undulation. The simulation results at the end of the paper prove the feasibility and advantages of the proposed operating mode.
A large Flow Signal Processing and Measurement Method based on Ultrasonic Gas Meter
Authors: Zhu Piao-xia , Li Yue-zhong , Zhang Yu-hua , Li Meng
Published: August 2020

Ultrasonic flowmeter is extensively used in petrochemical, metallurgical and other industries for its non-contact measurement, large measuring range, stable measurement results and no pressure loss. The time difference measurement method is adopted by the ultrasonic gas meter that can reduce the error caused by the variation of sound velocity with the temperature of the fluid. But there are some problems in the large flow point and small flow point in the time difference measurement method, such as low precision, low repeatability, poor stability. According to study the influence of flow velocity on ultrasonic echo signals, a method of variable threshold and variable gain based on peak detection is proposed and the prototype of gas ultrasonic flowmeter is designed in this paper. The national standard device, 100L automatic bell cover test device, is applied to verify the design scheme proposed in this paper. The experimental results indicates that the validity of variable threshold and variable gain ultrasonic signal processing method based on peak sampling is verified, in addition, the measurement accuracy and repeatability of the ultrasonic gas meter are enhanced at the point of large flow (large flow rate).
Multi-sensor weighted fusion algorithm based on improved TOPSIS
Authors: Tao Sheng , Hai-bao Xia
Published: August 2020

In the process of track fusion of multi-sensor target tracking, multi-sensor weighted fusion is used to overcome the shortcoming of incomplete single information source. In order to change the weight of each sensor participating in fusion in real time according to the merits and demerits of sensor information adaptively, a method of sensor weight calculation based on improved TOPSIS is proposed. Firstly, the local estimation and global prediction residuals of each sensor are composed into residuals matrix, from which the ideal solution is found, and then the relative closeness degree is calculated according to the grey correlation distance between the local estimation residuals and the ideal solution, so as to screen the sensors with high weight to participate in the fusion. The simulation results show that the tracking error of the algorithm after fusion is significantly reduced compared with the local estimation error of each sensor, and the tracking error of multiple sensors for the target can be realized.
Iterative adaptive approach STAP algorithm based on arc antenna array
Authors: Gao Zhiqi , Wang Ximing , Huang Pingping , Xu Wei , Zhang Zhenhua
Published: August 2020

The radar with arc antenna array has the advantages of all-orientation space scanning, simultaneous estimation of pitch-azimuth angle and good antenna pattern. However, due to the special geometry of the antenna, the echoes from different range cells are not independently and identically distributed (IID) samples, resulting in performance degradation in space-time adaptive processing technology. In this paper, the model of airborne radar with arc antenna array is established, and the clutter distribution is analyzed. The conclusion is that the nonlinear variation of spatial angular frequency with array element number results in the non-uniform clutter distribution in different range cells. Therefore, the traditional space-time adaptive processing is not fit for the target detection of arc array radar. Hence, the arc array-based iterative adaptive approach (IAA) algorithm is studied. The IAA algorithm is utilized to estimate the space-time spectrum, which can distinguish clutter and targets. Simulation experiments verify the effectiveness of the IAA algorithm in arc array radar.
Research on the Sea Spike Suppression Based on Range Domain Characteristics of Relatively High Resolution Radar
Authors: Hanqi Sun , Xiaoyong Wan
Published: August 2020

With the improvement of radar resolution, especially when the radar works in low erasing angle, the masking effect becomes more and more obvious, and a large number of sea spike arise. This paper mainly uses the relatively high resolution sea radar data, analyses the amplitude and frequency characteristics of the target and the sea peak. Finally, according to the differences of their range domain characteristics, we propose a range domain suppression method of sea spike. Experimental data analysis proves the validity and feasibility of the algorithm.
Research on Digital Copyright Infringement Based on Cloud Computing Environment
Authors: Zuo Xiangbin , Ding Huanhuan
Published: August 2020

Since the popularity of the Internet, more and more people have chosen to look for the information and resources they need on the Internet. People’s lives have gradually been changed by the Internet. Cloud storage brings new development opportunities, and the copyright protection issues involved in cloud storage are gradually emerging. Cloud storage has changed the original pattern among traditional information owners, disseminators and users, causing conflicts among copyright owners, cloud storage servers and information acquirers, and the problem of copyright protection has become increasingly prominent. The rapid development of network file sharing platforms such as cloud storage brings unprecedented challenges to copyright protection. The application and development of cloud storage also challenges the recognition of traditional copyright system, object and content, so we must balance the contribution of cloud storage to the exchange of information resources and protect the legitimate rights and interests of copyright holders.
A context and semantic enhanced UNet for semantic segmentation of high-resolution aerial imagery
Authors: Wang Fang , Xie Jindong
Published: August 2020

Semantic segmentation of high-resolution aerial images is of paramount importance in a wide range of remote sensing applications. The ever-increasing spatial resolution of aerial imagery brings about two specific challenges that incur labelling ambiguities: intra-class heterogeneity and inter-class homogeneity. To address these two challenges, a novel end-to-end semantic segmentation network for high-resolution aerial imagery, namely Context and Semantic Enhanced UNet (CSE-UNet), is proposed in this paper. Specifically, we exploit multi-level Receptive Field Block (RFB) based skip pathways to enhance the representational power of multi-scale contextual information, and therefore tackle the issue of intra-class heterogeneity. To solve the inter-class homogeneity problem, we propose a dual-path encoder where an auxiliary multi-kernel based feature encoding path is embed to produce strong semantic features at all levels to enlarge the inter-class differences. Experimental results shows that our proposed CSE-UNet achieves competitive performance and outperforms UNet and several other deep networks on the ISPRS Potsdam and Vaihingen datasets.
Designing preamplifier for sensing atmospheric electrostatic field strength via supercapacitive sensor
Authors: Wu Changhao , Xiong Yi , Zeng Wei
Published: August 2020

In order to effectively obtain the signal from sensor, the analogy signal needs to be amplified and then converted into a digital signal for matching to the sensor characteristics. With a supercapacitive electric field sensor based on graphene aerogel, the response current signal from the electric field sensor is weak and unstable. Herein, a high gain and low noise preamplifier is developed, and an amplifier circuit with double T-type feedback network is proposed to reduce the Johnson noise for the amplifier. This design can reduce the thermal noise of resistance by using the smaller resistance under the same gain, and it can effectively reduce the interference of peak noise by adding the feedback capacitance, so as to improve the detection accuracy. The simulation results show that under the same gain condition, the Johnson noise can be reduced by 46% and the detection accuracy can be improved by 12% compared with the traditional T-type feedback network.
The Research on a parallel and synchronous encoding and decoding method of multi-level LDPC
Authors: Zhou Hui , Zhao Hairu , Zhao Shengping , An Zhenzhou
Published: August 2020

Based on the research of Binary Low-Density Parity-Check (LDPC) code, this paper studies the Quaternary LDPC code. Based on LU decomposition and BP algorithm, a block and partition parallel mode is proposed to make the data receiving and code compiling process run at the same time, which not only improves the coding speed, but also greatly reduces the time delay caused by data receiving before coding, and the feasibility of the algorithm is verified by simulation. At the same time, synchronization technology is added to the system to minimize the error caused by parallel transmission and ensure the reliability of data reception. The simulation results show that the new algorithm can effectively reduce the time delay and the bit error rate to ensure the effectiveness and reliability of information transmission.
Game Design and Implementation in Popular Science Education Based on Virtual Reality Maze
Authors: Ran Tao , Xin Gao
Published: August 2020

With the development of science and technology, VR technology has been widely used in various fields, and promoted the rapid development of various fields. It has become an important direction of market development in game design, and VR technology has many advantages in practical application. According to the research and development concept of popular science game and VR maze game, this paper designs the game by making use of what they have in common. Effective integration of knowledge popularization and electronic games, through the VR maze popular science games to open up new ways of knowledge dissemination.
Speech noise Reduction and Automatic Recognition Based on Active Detection Algorithm
Authors: Mo Jianli , Wu Chenyu
Published: August 2020

In practice, people need to carry out intelligent speech analysis on the sound collected or recorded in some specific scenes. These sounds are recordings of a period of time in some specific places. Due to the influence of the phonetic environment and the limitation of acquisition or recording means, the actual effective and available voice content is very small, and the voice quality is relatively poor. Therefore, it is necessary to enhance the speech of the acquired recordings, eliminate the noise and the interference of non-human voice, and improve the understanding degree of the target’s voice. Voice quality is improved, and the voice can be targeted content recognition and keywords detected, the audio files into a text file, by setting the key words found early warning, the valuable data information in mass speech quick preview, retrieval, analysis, according to the established goals and objectives by using automatic speech recognition in order to improve work efficiency.
A Semi-Supervised Generative Model Integrating Both Syntactic and Semantic Features for Bacterial Subcellular Localization Extraction
Authors: Shi Zhongmin , Zhong Li , Lin Guishi
Published: August 2020

Our study on the Bacterial Subcellular Localizations (BPLs) extraction1 focuses on generative learning. We propose a generative model extracting BPLs from MEDLINE abstracts. The model integrates both syntactic and semantic features of a sentence, and capable of identifies biomedical named-entities and relations at the same time from a large set of noisy biomedical data. The overall performance of the model exhibits a significant improvement comparing to a supervised alternative.
Research on Army and Local Government Integrated Joint Command Information Platform
Authors: Zhen Zi-qing
Published: August 2020

The current national comprehensive security is facing new challenges. On the basis of the analysis of the current status of the construction of the military and local command systems, the concept of the construction of an integrated military command command information platform is proposed. It analyzes the functional requirements of the integrated military-civilian integrated command information platform, designs the system structure and system operation process, and finally discusses the key technologies of the integrated military-civilian integrated command information platform.
Test Method of Real-time Kinematic and Its Application in Terminal Positioning Performance test
Authors: Zhang Qinjuan , Jing Huanhuan , Wang Na , Tang Lei
Published: August 2020

The real-time kinematic technology has been widely used in positioning terminals. The principle, test method of the real-time kinematic technology and its application in terminal positioning test are presented in this paper. A virtual drive test system is developed by using the real-time kinematic technology, and the positioning performance of the terminal is tested under different road sections. The test results show that the system can evaluate the terminals performance under the real application scenarios very well.
Analysis on the Applicability of the Random Forest
Authors: Zhu Tongtian
Published: August 2020

Random forest is a flexible algorithm with a wide range of applications and performs well on a large number of data sets. Besides, Random forest is immune to statistical assumptions as well as preprocessing burden and can handle a large data set with high dimensionality and missing values. Nevertheless, random forest struggles with high-cardinality categorical variables, unbalanced data, time series forecasting, variables interpretation, and is sensitive to hyperparameter. Thus, random forest is relatively suitable for processing high-dimensional data and data with missing variables. Besides, random forest works well with a large amount of data, which is previously unprocessed. Moreover, random forest is an appropriate method, when there are prior statistical assumptions. However, random forest is non-ideal, when processing data with endogenous temporal effects or high-cardinality categorical variables, as well as when the interpretation is the primary goal. Despite the shortcomings of the random forest, there are still some improvements that can be made. It will be more convenient for users to screen methods, if there is a rating system to give an overall score towards all alternative algorithms depending on the input data and the users’ goals.
Review and Prospect of China Management Accounting in the Information Age
Authors: He Lanfang
Published: August 2020

With the advent of the information age, big data, “Internet +", “intelligence +", “cloud computing” and other technological methods emerge in endlessly, the basic financial accounting work will gradually be replaced by intelligent robots, and this is a great opportunity to promote the development and transformation of management accounting. Management accounting, as a product of the combination of management and accounting, requires a large amount of information and data in order to play a specific role. In the context of the information era, management accounting can rely on the assistance of scientific and technological means to integrate and analyze enterprise information, and further promote enterprise decision-making, control, investment, etc. To serve the overall development situation, management accounting is promising. This article reviews the development of management accounting since the founding of the People’s Republic of China and summarizes the problems existing in the development process. On this basis, it provides guiding opinions and suggestions for further improving China’s management accounting.
Research and Application of Knowledge Graph in Teaching: Take the database course as an example
Authors: Qin Yuehua , Cao Han , Xue Leyi
Published: August 2020

With the rapid development of technologies such as artificial intelligence and deep learning, education informatization has entered the 2.0 era with artificial intelligence as the main feature. As an important part of artificial intelligence technology, knowledge graph provides possibilities for smart education and promotes the innovation and development of smart education. At this stage, the core concepts and knowledge systems of some computer science disciplines need further clarification and improvement. Using a large amount of course-related information to construct an educational knowledge graph, processing and analyzing the knowledge points in the course, extracting the knowledge entities and effectively integrating them, can greatly help to clarify the knowledge system of the subject. The improvement of the teaching quality of this subject is of great significance. Therefore, this paper selects the construction of educational knowledge graph as research content, and uses database courses as examples of graph construction for research. The BIO tagging method is used to construct the database subject dataset, at the same time, it builds knowledge card based on educational knowledge graph to achieve database teaching wisdom, systematic teaching content, integration of knowledge fragments and improve the quality of learning.
Research on Data Processing Architecture of NQI Service Platform in Intelligent Measurement Domain
Authors: Fang Xu , Liu Yongguang , Wang Yong
Published: August 2020

At present, the quality control and management of smart meters exist in production enterprises and power grid companies respectively. There are some problems, such as weak system, lack of coordination, and lack of overall technical solution ability. By carrying out the design of NQI service platform to support the quality improvement of smart meters, the quality data collection and quality monitoring of smart meters in multiple factors, dimensions and the whole process are realized, and the quality level of smart meters is promoted comprehensively. The NQI service platform focuses on the storage and processing of massive quality data of smart meters, improving the efficiency of quality data mining and utilization, and achieving the overall quality improvement of smart meter industry. In this paper, through the analysis and research of service scenario, the massive quality data analysis and processing mechanism of intelligent power meter is designed.
Pressure- and temperature- driven phase transitions in pyridine
Authors: Gromnitskaya E L , Danilov I V , Kondrin M V , Lyapin A G , Brazhkin V V
Published: August 2020

Studies of aromatic and heteroaromatic compounds under high pressure in recent years have attracted great attention to the possibility of the synthesis of amorphous hydrogenated materials with attractive technological properties. In this context, pyridine is of particular interest in terms of its rich polymorphism. We studied the liquid and solid phases of pyridine by dielectric spectroscopy and pulsed ultrasonic methods in the pressure and temperature range P <4.2 GPa and 78 <T <350 K. It is shown that up to 20% of the sample passes into the glassy state during crystallization from the melt to the low-pressure phase. Disordered phase has a high dielectric constant and a high absorption coefficient of ultrasound. All these features are absent in the high pressure phase.
Journal of Physics: Conference Series High-pressure specific heat technique to uncover novel states of quantum matter
Authors: Larrea J Julio , Martelli V , Rønnow H M
Published: August 2020

AC-specific heat measurements remain as the foremost thermodynamic experimental method to underpin phase transitions in tiny samples. However, its performance under combined extreme conditions of high-pressure, very low temperature and intense magnetic fields needs to be broadly extended for investigation of quantum phase transition in strongly correlated electron systems. In this communication, we discuss the determination of specific heat on the quantum paramagnetic—insulator SrCu2(BO3)2 by applying the AC-specific heat technique under extreme conditions. In order to apply this technique to insulating samples we sputtered a metallic thin film-heater and attached thermometer onto sample. Besides that, we performed full frequency scans with the aim to get quantitative specific heat data. Our results show that we can determine the sample heat capacity within 5% of accuracy respect to an adiabatic technique. This allows to uncover low energy scales that characterize the ground state of quantum spin entanglement in SrCu2(BO3)2.
Exploring pressure effects on metallic nanoparticles and surrounding media through plasmonic sensing
Authors: Martín-Sánchez C , Seibt S , Barreda-Argüeso J A , Rodríguez F
Published: August 2020

The sensing capabilities of gold nanorods under high-pressure conditions were investigated in methanol-ethanol mixtures (up to 13 GPa) and in water (up to 9 GPa) through their optical extinction. The longitudinal SPR band of AuNR exhibits a redshift with pressure which is the result of two main competing effects: compression of the conduction electrons which increases the bulk plasma frequency (blueshift) and increase in the solvent density (redshift). The variation in de SPR peak wavelength allows us to estimate the bulk modulus of the gold nanoparticles with a precision of 10 % and to obtain analytical functions providing the pressure dependence of the refractive index of water in three phases: liquid, ice VI and ice VII. Furthermore, the SPR band shows abrupt jumps at the liquid to ice phase VI and ice phase VII transitions, which are in accordance with the first-order character of these transitions.
Detonation properties of the mixtures of tetranitromethane/methanol and tetranitromethane/nitrobenzene
Authors: Mochalova V M , Utkin A V , Rykova V E , Koldunov S A
Published: August 2020

In this work, the reaction zone structure, stability of detonation waves and limits of detonation propagation in the mixtures of tetranitromethane/methanol and tetranitromethane/nitrobenzene depending on the diluent concentration, were studied by a VISAR laser interferometer with a nanosecond time resolution. In the experiments, a sharp change in the reaction zone at the concentration of diluents in the vicinity of stoichiometry is observed – the amplitude of von Neumann spike decreases significantly. This is due to an increase in the initial reaction rate, which leads to the decomposition of HE directly in the shock wave front. It was found that the addition of diluent resulted in an increase in the detonation velocity of the tetranitromethane/diluent mixture in the vicinity of the stoichiometric concentration (about 25% of methanol or nitrobenzene). In almost the entire concentration range, the detonation waves are stable with respect to the formation of the cellular structure of the front. At the same time, in the range of diluent concentration of 15-35%, a poor reproducibility of the amplitude values of the particle velocity from shot to shot is observed. This is probably due to the longitudinal instability of the detonation waves in the mixture.
Study of the shock-wave compressibility of heterogeneous anisotropic materials
Authors: Mochalova V M , Utkin A V , Rykova V E , Yu Shakula M , Yakushev V V
Published: August 2020

Investigation of shock-wave compressibility of three anisotropic materials (carbon fibre reinforced plastic, textolite and kevlar) was performed by a VISAR laser interferometer. Two of these composites consist of the same aramid fibers (textolite and kevlar) and two of them have the same structure (CFRP and kevlar). The structure of compression pulse and shock wave velocity of materials were obtained in each experiment. The shock wave structure in tested composites significantly depends on the fibers orientation - a two-wave configuration is recorded in almost the entire range of studied pressures when shock wave propagates along the fibers. Hugoniot parameters of anisotropic materials were obtained in the coordinates of the shock wave velocity D – particle velocity u for two orientations of the fibers. Hugoniots of kevlar, textolite and CFRP with perpendicular orientation of the fibers are parallel to each other. For kevlar and CFRP, the shock wave compressibility almost does not depend on the fibers orientation relative to the direction of the shock wave propagation. In textolite with parallel orientation of the fibers, the shock compressibility is determined by the properties of unidirectional aramid fibers, and Hugoniots for two directions differ significantly.
Density functional theory plane-wave/pseudopotential calculations of the equation of state of rhenium in the terapascal regime
Authors: Rech G L , Perottoni C A
Published: August 2020

The equation of state (EOS) of hexagonal close-packed rhenium has been previously determined up to 1.5 TPa (V/V0 = 0.46) using all-electron (AE) density functional theory (DFT) including core relativistic effects [Phys. Rev. B 100, 174107 (2019)]. This work focuses on assessing the validity of pseudopotentials at such high-pressures, above 1 terapascal (TPa), by comparing the EOS obtained using plane-wave/pseudopotentials (PW/PPs) with previous AE calculations. Both ONCV pseudopotentials tested (PBE and PBEsol) yield results in good agreement with all-electron calculations. The fitted parameters of the Rose-Vinet EOS, the bulk modulus, B0 (380(2) GPa and 379(3) GPa for the PBE and PBEsol PPs), and its pressure derivative, B0’(4.58(2) and 4.59(3) for the PBE and PBEsol PPs), are in good agreement with previous all-electron results (B0=367(5) GPa and B0’=4.64(3)). The agreement is worse for the equilibrium volume at zero pressure, V0 (199.9(2) Bohr3 and 199.2(2) Bohr3 for PBE and PBEsol PPs, versus 196.7(3) Bohr3 for AE). Even so, for a given V/V0 ratio, the pressures estimated using the EOS derived from the PPs and AE calculations are in very good agreement, thus suggesting that the PPs used in this study are valid even at such high compression regime.
Global surface air temperatures in CMIP6: historical performance and future changes
Authors: Fan Xuewei , Duan Qingyun , Shen Chenwei , Wu Yi , Xing Chang
Published: August 2020

Surface air temperature outputs from 16 global climate models participating in the sixth phase of the coupled model intercomparison project (CMIP6) were used to evaluate agreement with observations over the global land surface for the period 1901–2014. Projections of multi-model mean under four different shared socioeconomic pathways were also examined. The results reveal that the majority of models reasonably capture the dominant features of the spatial variations in observed temperature with a pattern correlation typically greater than 0.98, but with large variability across models and regions. In addition, the CMIP6 mean can capture the trends of global surface temperatures shown by the observational data during 1901–1940 (warming), 1941–1970 (cooling) and 1971–2014 (rapid warming). By the end of the 21st century, the global temperature under different scenarios is projected to increase by 1.18 °C/100 yr (SSP1-2.6), 3.22 °C/100 yr (SSP2-4.5), 5.50 °C/100 yr (SSP3-7.0) and 7.20 °C/100 yr (SSP5-8.5), with greater warming projected over the high latitudes of the northern hemisphere and weaker warming over the tropics and the southern hemisphere. Results of probability density distributions further indicate that large increases in the frequency and magnitude of warm extremes over the global land may occur in the future.