bluuebunny/crossref_metadata_2025 huggingface dataset:
Hierarchical global fast terminal sliding‐mode control for a bridge travelling crane system
Authors: Yang Weilin , Chen Jiayu , Xu Dezhi , Yan Xinggang
Published: January 2021

The bridge crane system is a typical under‐actuated system that is widely used in production and life. Although various scholars have conducted extensive research on the bridge crane system in recent years, there are still many problems, such as the trajectory planning of the cart and the anti‐sway control of the cargo. In order to tackle the problem of the anti‐sway control of the cargo, a hierarchical global fast terminal sliding‐mode control (H‐GFTSMC) is developed in this work. First, the Lagrange equations are used to model the system dynamics. Then, an appropriate hierarchical global fast terminal sliding‐mode controller is designed to achieve anti‐sway control of the cargo, and it is proved that each sliding‐mode surface is progressively stable. A series of simulations were implemented to verify the effectiveness of the control method. The simulation results show that the H‐GFTSMC has better control performance compared with the proportional–integral–derivative control method. When changing the cable length or adding non‐negligible noise to the system, the H‐GFTSMC still has good robustness.
Performance analysis of horizontal ground source heat pump for building cooling in arid Saharan climate: thermal-economic modeling and optimization on TRNSYS
Authors: Korichi Sabrin , Bouchekima Bachir , Naili Nabiha , Azzouzi Messaouda
Published: January 2021

This paper presents a feasibility and performance study of ground source heat pump (GSHP) coupled with horizontal ground heat exchanger (HGHX) used for cooling residential unit equipped with radiant floor system (RFs) under the meteorological conditions of Saharan environment in Ouargla, city located in Southeast Algeria. A dynamic simulation system is developed using TRNSYS software for modeling the performance of the GSHP system. To verify the reliability of GSHP including HGHX system programs, the modeling procedure was validated against experimental data from a horizontal ground source heat pump system (HGSHPs) installed at the Research and Technology Center of Energy (CRTEn), Tunisia, and a good agreement was obtained. Then, to obtain an acceptable balance between system efficiency and total cost of HGSHPs an economic analysis was carried out to determine the optimum design parameters of the HGHX. The simulation results obtained from this study indicated that the HGSHPs could effectively solve cooling problem and reduce traditional energy consumption in the Saharan areas; it is possible to lower the mean indoor air temperature below 27 °C and raise the average relative humidity to reach 73.97%. By concentrating principally on the thermal-economic optimization, the optimized COP of the GSHP that combines the reliability and economy of cooling in long term was found to be 3.89.
Le vélo à l’adolescence sous le regard de la santé : révélateur et support des rapports sociaux de sexe, de classe et de territoire
Authors: Sayagh David
Published: January 2021

Face au déclin de l’activité physique des jeunes, les mobilités à vélo représentent un enjeu considérable sur le plan sanitaire. En s’appuyant sur une enquête menée par observations et entretiens semi-directifs (n = 101), cet article vise à identifier − auprès d’un public adolescent – des appropriations différenciées du vélo en regard avec la santé, et à analyser dans quelle mesure celles-ci sont sous-tendues par les rapports sociaux de sexe, dans leurs articulations avec les rapports sociaux de classe, d’âge, et de territoire. Si le vélo peut être approprié pour le bien-être et/ou pour essayer de maigrir et/ou pour rester mince et/ou pour préserver ses qualités physiques et/ou pour les renforcer et/ou pour se protéger des agressions et/ou pour se risquer, ces appropriations sont le plus souvent sexuées, socialement situées et parfois encouragées par le contexte résidentiel. L’analyse démontre ainsi l’importance d’étudier les articulations entre les socialisations urbaines, sportives et mobilitaires des jeunes. Le vélo apparaît à la fois comme un révélateur et un support des rapports sociaux de sexe, de classe et de territoire. S’il est souhaité que sa promotion joue un rôle central sur le plan de la santé, la réduction des inégalités d’accès à l’espace public devrait constituer un objectif prioritaire.
Behandle deinen Patienten und nicht Covid-19!
Authors: Müller Dominik
Published: January 2021

Die homöopathischen Behandlungsverläufe (ambulant / stationär) von 4 Patienten, die sich mit Covid-19 infiziert haben, werden vorgestellt. Wichtige Aspekte wie die Häufigkeit von Follow-ups, Erfassung von Vitalparametern, Möglichkeiten der Arzneiwahl, Differenzialdiagnose, Potenzhöhe und Häufigkeit der Arzneigabe werden diskutiert.
Composition-graded multilayer nanogranular films enabling broadband tunneling magneto-dielectric effect: Role of the granular distribution
Authors: Cao Yang , Kobayashi Nobukiyo , Ohnuma Shigehiro , Masumoto Hiroshi
Published: January 2021

The tunneling magneto-dielectric (TMD) effect, which causes a magnetic field-induced increase in the dielectric permittivity (ε′0) of nanogranular films, is promising for use in multifunctional devices. However, the frequency response of the TMD effect features a peak dielectric change (the TMD ratio, Δε′/ε′0) at a specific frequency, which inevitably limits the utility of the effect to within a narrow frequency range. To achieve the high TMD effect over a wider frequency band, we experimentally and theoretically report composition-graded multilayer (CGM) Co-MgF2 nanogranular films (i.e., with a step-varied granular Co content) with still high TMD ratios beyond this particular frequency range. Theoretical fittings of the experimental dielectric and TMD results indicate that the wide inter-granular spacing distribution in CGM films represents the origin of the broadband TMD effect. This study clarifies the critical role of the granular distribution in regulating the frequency response of the TMD properties. The proposed CGM structure, which can go beyond the limitations of conventional uniform nanogranular materials, will enable broadband magnetoelectric device applications of the TMD effect.
Phase change materials in photonic devices
Authors: Gong Zilun , Yang Fuyi , Wang Letian , Chen Rui , Wu Junqiao , Grigoropoulos Costas P. , Yao Jie
Published: January 2021

Recent developments in reconfigurable photonic devices highly rely on the effective refractive index change enabled by phase change materials (PCMs) as either dielectric surroundings or constituting materials. This universal characteristic, tunable refractive index, is shared among various kinds of PCMs and has been successfully utilized to achieve multilevel modulations for both free-space and integrated photonics. In this Perspective, we briefly recapitulate the fundamental mechanisms of phase transitions for three dominant PCMs. The progress in integrating different PCMs with on-chip silicon photonics and periodic antenna arrays are reviewed and analyzed in parallel. We also discuss the existing problems of PCM photonics, for example, the compatibility with commercial production line, the stability issue, and accessibility of the stimuli. In the end, we provide the outlook for the improving material engineering of PCM and multi-functional PCM-based photonics devices.
Integrated nanophotonics for the development of fully functional quantum circuits based on on-demand single-photon emitters
Authors: Rodt S. , Reitzenstein S.
Published: January 2021

In recent years, research on integrated quantum circuits has developed rapidly and exciting results have been achieved. The overarching goal of this emerging research direction in the field of modern quantum technology is the scalable integration of quantum functionality on robust chips. Such chips can work independently of one another, but it is even more interesting to develop them modularly for integration into larger quantum networks, thereby linking quantum computation and quantum communication in the same framework. In this context, the ongoing development and further optimization of integrated quantum circuits aim, inter alia, to achieve a quantum advantage in the area of quantum computing and to pave the way for multipartite quantum networks. The functionality of such chips is essentially based on single-photon operations, such as interference at beam splitters in combination with phase shifters in the field of linear optical quantum computing and Bell-state measurements for entanglement swapping in long-distance quantum networks. While individual functionalities such as CNOT gates and more complex quantum computing operations such as boson sampling in a combination of waveguide chips and external photon sources and detectors were successfully demonstrated, the field is currently facing the major challenge of integrating all necessary components monolithically on chip in order to exploit the full potential of integrated quantum nanophotonics. The present Perspective discusses the status and the present challenges of integrated quantum nanophotonics based on on-demand single-photon emitters and gives an outlook on required developments to enter the next level of fully functional quantum circuits for photonic quantum technology.
Oxygen defect dominated photoluminescence emission of ScxAl1−xN grown by molecular beam epitaxy
Authors: Wang Ping , Wang Boyu , Laleyan David Arto , Pandey Ayush , Wu Yuanpeng , Sun Yi , Liu Xianhe , Deng Zihao , Kioupakis Emmanouil , Mi Zetian
Published: January 2021

A fundamental understanding and control of impurity incorporation and charge carrier recombination are critical for emerging ScxAl1−xN electronics, optoelectronics, and photonics. We report on the photoluminescence properties of ScxAl1−xN grown by plasma-assisted molecular beam epitaxy with varying growth temperatures and Sc contents. Bright and broad emission comprising a dominant peak at ∼3.52 eV and a weak peak at ∼2.90 eV was observed in Sc0.05Al0.95N. The origin of the ∼3.52 eV emission line is attributed to charge carrier recombination from the localized excited state of (Vcation-ON)2−/− to its ground state, whereas the second peak at ∼2.90 eV results from charge carrier recombination of isolated Vcation3−/2− to the valence band. We further show that oxygen defect-related emission can be significantly suppressed by increasing growth temperature. This work sheds light on the recombination dynamics of photoexcited carriers in ScxAl1−xN and further offers insight into how to improve the optical and electrical properties of ScxAl1−xN that are relevant for a broad range of applications.
Coding metasurface holography with polarization-multiplexed functionality
Authors: Shang Guanyu , Li Haoyu , Wang Zhuochao , Zhang Kuang , Burokur Shah Nawaz , Liu Jian , Wu Qun , Ding Xuemei , Ding Xumin
Published: January 2021

Multiplexing technologies can be used as a platform for low-cost, high-performance, and large-capacity holographic displays and data storage systems. In this paper, a polarization multiplexed method is proposed to realize two different information channels under orthogonally linear-polarized incidences utilizing the coding metasurface. Based on the modified weighted Gerchberg–Saxton (GSW) algorithm, a two-bit coding metasurface is designed with a set of double-layer cross-type meta-atoms to encode the holographic phase information, which can reflect two independent holographic images with respect to different incident polarization. The experimental results agree well with the numerical simulations and the theoretical predictions, which make the proposed multiplexed two-bit coding meta-hologram a great potential in numerous applications such as data storage and information processing.
Testing the isomorph invariance of the bridge functions of Yukawa one-component plasmas
Authors: Lucco Castello F. , Tolias P. , Dyre J. C.
Published: January 2021

It has been recently conjectured that bridge functions remain nearly invariant along phase diagram lines of constant excess entropy for the broad class of R-simple liquids. To test this hypothesis, the bridge functions of Yukawa systems are computed outside the correlation void with the Ornstein–Zernike inversion method employing structural input from ultra-accurate molecular dynamics simulations and inside the correlation void with the cavity distribution method employing structural input from ultra-long specially designed molecular dynamics simulations featuring a tagged particle pair. Yukawa bridge functions are revealed to be isomorph invariant to a very high degree. The observed invariance is not exact, however, since isomorphic deviations exceed the overall uncertainties.
Carbon cluster formation and mobility degradation in 4H-SiC MOSFETs
Authors: Zhang Zhaofu , Wang Zhen , Guo Yuzheng , Robertson John
Published: January 2021

The performance of SiC MOSFETs is limited by many defects at the SiC/SiO2 interface. However, there are no fully consistent atomic models of these defects or how their large densities arise. We show how the high heat of formation of SiO2 causes a selective oxidation of Si in SiC, leaving carbon clusters in SiO2. We consider chemical potentials across the interface from both the thermochemical and oxidation kinetics viewpoint. SiO2 native defects give states too far in energy from the SiC band edges, while defects in bulk SiC have too high a formation energy. Only carbon clusters have a low enough formation energy to give sufficient defect densities to account for the mobility loss, and experimental evidence for them is discussed.
Mapping current profiles of point-contacted graphene devices using single-spin scanning magnetometer
Authors: Lee Myeongwon , Jang Seong , Jung Woochan , Lee Yuhan , Taniguchi Takashi , Watanabe Kenji , Kim Ha-Reem , Park Hong-Gyu , Lee Gil-Ho , Lee Donghun
Published: January 2021

We demonstrate two-dimensional mapping of current flow in graphene devices by using a single-spin scanning magnetometer based on a nitrogen-vacancy defect center in diamond. We first image the stray magnetic field generated by the current and then reconstruct the current density map from the field data. We focus on the visualization of current flow around a small sized current source of ∼500 nm diameter, which works as an effective point contact. In this paper, we study two types of point-contacted graphene devices and find that the overall current profiles agree with the expected behavior of electron flow in the diffusive transport regime. This work could offer a route to explore interesting carrier dynamics of graphene including ballistic and hydrodynamic transport regimes.
Current switching of interface antiferromagnet in ferromagnet/antiferromagnet heterostructure
Authors: Yan Z. , Yun J. J. , Sui W. B. , Xi L. , Xie Z. T. , Cao J. W. , Si M. S. , Yang D. Z. , Xue D. S.
Published: January 2021

Recently, electrical switching of interface states in nonferromagnet/ferromagnet (FM)/antiferromagnet (AFM) heterostructure using spin–orbit torque (SOT) is promising due to its high efficiency, zero magnetic field, and multilevel memory state. However, the reversal mechanism of the AFM interface state is still unclear. In this work, we explained the bipolar current switching of the AFM interface state at zero magnetic field by spin–orbit torque (SOT) in a perpendicularly magnetized Pt/Co/IrMn multilayer. By considering symmetry, we reveal that the mechanism behind the AFM interface bipolar current switching is consistent with FM layers perpendicularly switching induced by SOT. The distinct AFM bipolar current switching by SOT is contributed to the symmetry broken by adjacent FM interface coupling. Under such broken symmetry, the antiparallel interface configuration (AP) between FM and AFM could be switched to parallel configuration (P) for both positive and negative currents; however, P is only allowed to be switched to the AFM multiple domain configuration (M), instead of AP. Our result will be helpful for the formulation of a comprehensive understanding of AFM switching induced by SOT and for the development of the interface AFM spintronic devices.
Overview and compatibility of Northern Territory plot-based vegetation data with the National Vegetation Classification System and future vegetation typologies
Authors: Lewis Donna , Brocklehurst Peter , Milne Damian , Cowie Ian I. D. , Cuff Nicholas
Published: January 2021

Plot-based vegetation data have been collected in the Northern Territory since the 1950s. The purpose of data collection broadly includes land resource and vegetation community mapping, flora surveys, habitat assessment for fauna surveys, rare and threatened species surveys, development assessment and monitoring. These datasets were stored in disparate database systems until 2012. Currently over 423 surveys, 69 000 geocoded plots, comprising almost 838 164 flora records, are maintained using a corporate database. The data are of varying degrees of attribute detail including floristics, structure, strata and associated environmental information. The original territory-wide standardised vegetation classification was based on the 1:1 000 000 vegetation mapping project where 112 broad vegetation types were described from 2245 plots using an intuitive appraisal of numerical analytical techniques. This approach continues to be used; however, a standard method would be desirable to classify plot data into meaningful vegetation types in the Northern Territory. The National Vegetation Information System (vegetation hierarchy) was used to qualitatively assess the level of detail of vegetation plot data. Only 9% of the plot data can be assigned to sub-association level, and 28% to the association level. In addition to reviewing the compatibility of plot data to the National Vegetation Information System, we also provide examples of how it can conform with the International Vegetation Classification.
Multimorbidity through the lens of life-limiting illness: how helpful are Australian clinical practice guidelines to its management in primary care?
Authors: Damarell Raechel A. , Morgan Deidre D. , Tieman Jennifer J. , Healey David F.
Published: January 2021

This study assessed Australian clinical practice guidelines for life-limiting index conditions for the extent to which they acknowledged comorbidities and framed management recommendations within the context of older age and reduced life expectancy. A comprehensive search identified current, evidence-based Australian guidelines for chronic life-limiting conditions directed at general practitioners. Guideline content was analysed qualitatively before comorbidity acknowledgements were quantified using a 17-item checklist. Full guidelines were quality appraised using AGREE-II. Ten documents covering chronic obstructive pulmonary disease, heart failure, cancer pain, dementia and palliative care in aged care were identified. Most guidelines addressed one ‘comorbid’ condition and prompted clinicians to consider patient quality of life and personal preferences. Fewer addressed burden of treatment and half suggested modifying treatments to account for limited life expectancy, age or time horizon to benefit. Half warned of potential adverse drug interactions. Guidelines were of moderate to very high quality. Guidelines naturally prioritised their index condition, directing attention to only the most common comorbidities. However, there may be scope to include more condition-agnostic guidance on multimorbidity management. This might be modelled on the ‘guiding principles’ approach now emerging internationally from organisations such as the American Geriatrics Society in response to increasing multimorbidity prevalence and evidence limitations.
2020: An unusual year
Authors: Eisner David A.
Published: January 2021

Update from the Editor-in-Chief
Reconfigurable laminates enable multifunctional robotic building blocks
Authors: Jiang Mingsong , Gravish Nicholas
Published: January 2021

Folding and assembling of two-dimensional laminated materials have greatly facilitated robot fabrication by creating robots with lightweight body frames, articulated joints, and embedded actuators and sensors. The combinations of rigid laminates bridged by thin-film flexures, often called rigid-flex linkages, have been extensively used in micro- and macro-scale robots to achieve complex joint motions with simplified kinematic and dynamic properties. Much like traditional robots these rigid-flex laminate robots are designed with a fixed body-plan, and thus may face challenges when environments require mechanical reconfiguration such as stiffening joints for load support or changing appendage morphologies for navigating confined spaces. Recent advances in adaptive materials and smart actuators have highlighted the features that robots with morphable geometries and tunable mechanical properties can provide, such as self-folding joints and variable stiffness and damping mechanisms. However, incorporation of these reconfigurable elements into laminate robots has been limited. In this paper, we present a new method for creating quasi two-dimensional structures for robotics, called reconfigurable laminates, that use geometric reconfiguration of laminate layers to alter passive mechanical properties and actuate joints. Unlike traditional rigid-flex linkages with single-layered flexures, here we create laminate joints with dual-layered soft hinges and rigid channels allowing a multitude of reconfiguration opportunities including: sliding-layer laminates for passive stiffness control, snapping-hinge locks for reconfigurable joints, and buckle-bend joints for bending actuation. Through experimental characterization we demonstrate the capabilities of these multifunctional robotic building blocks.
Impact of physicochemical properties on band gap energy and glass transition temperature of (GeS2)10(Sb2S3)90−x(AgI)x chalcohalide glasses for Near-IR applications
Authors: Boukhris Imed , Hegazy H H
Published: January 2021

The dependence of band gap energy (Eg) and glass-transition temperature (Tg) on physico-chemical properties for the (GeS2)10(Sb2S3)90−x(AgI)x (10 ≤ x ≤ 50 at%) chalcohalide glasses were theoretically investigated. Chalcohalide glasses have wide technological applications owing to the aptitude of tuning their optical band gap through composition change. Therefore, Eg of the studied chalcohalide glasses was estimated using different methods, and it was turned out that it decreased as the AgI amount increases. This decrease was elucidated in terms of physico-chemical properties. In addition, we determined the positions of conduction band (ECB) and valence band (EVB) by using the computed values of Eg. The density and molar volume increased while the packing density decreased by adding AgI. The overall coordination number (CN), crosslinking density (CD), constraints number (Ns), cohesive energy (CE), heat of atomization (Hs) and overall mean bonds energy (〈E〉); computed via the chemical bond approach (CBA); decreased with the increment of AgI amount. In contrary, the floppy (F) and mean bonds energy (Es) increased. Finally, two estimations of Tg were presented based on 〈E〉 and CN. The two estimations showed a decreasing trend when adding AgI content.
An Advanced Fourier Descriptor Based on Centroid Contour Distances
Authors: Nan Liao Nan , Guo Baolong , Li Zekun , Zheng Yan
Published: January 2021

In order to distinguish two shapes with similar centroid contour distances. This paper proposes a novel descriptor-AFD-CCD (advanced Fourier descriptor based on centroid contour distances), which is based on FD-CCD ( Fourier descriptor based on centroid contour distance ) descriptor. FD-CCD only provides the distance information from the centroid point to the contour point, and the lack of direction information affects the accuracy of matching. The algorithm uses circularity and rectangularity to supplement discriminability, with low computational complexity. Tests were performed on three datasets. The experimental results show that AFD-CCD has further improved the matching accuracy while ensuring that the matching speed does not decrease.
Investigation of real-time optimization based on CAN bus
Authors: Du Feng , Cai Yijie , Guan Zhiwei , Tang Fengmin , Wu Di , Shi Heping , Wang Tong
Published: January 2021

Aiming at the problem of CAN bus network transmission delay which affects the transmission rate, a bus network transmission delay model is established. The main indicators of network transmission delay are modeled. A hybrid optimization combining message offset compensation and identifier optimization is proposed. In terms of overall optimization, an optimization method for message segmentation and encoding scheme is designed, and a method for offset compensation of delayed messages is designed for partial parts. Symtavision software is used to simulate network conditions of the two CAN buses. Analyse the main indicators of delay after the optimization plan is adopted. The simulation results show that the hybrid optimization scheme can reduce the delay by more than 16% compared with before, which significantly improves the network communication quality, and improves the network transmission rate and scalability.
Prediction of Sea Clutter Based on Recurrent Neural Network
Authors: Wang Wenyuan , Ji Tingting , Sun Jinghao
Published: January 2021

As radar sea clutter has chaotic characteristics, a prediction model can be established to predict sea clutter according to short-term predictability of chaotic time series. Therefore, this paper proposes a sea clutter amplitude prediction model based on LSTM, Stacked LSTM and Nested LSTM. This paper first obtains the best state space for sea clutter prediction according to the phase space reconstruction theory and establishes the prediction equation, then uses three networks to predict the sea clutter amplitude, and finally compares the effects of the three neural networks and analyzes the factors that affect the prediction precision. The experimental results on the IPIX radar data and P-band radar data show that, the model used in this paper has a smaller prediction error than RBF, and the prediction performance is better. The model can achieve high-precision and high-efficiency prediction of sea clutter and has verified the effectiveness of the method.
Analysis of Equipment Anti-interference Problem in Electronic Information Communication Engineering
Authors: Xie Yang , Qiu Xiuling
Published: January 2021

This article analyzes the role of equipment anti-interference in electronic information and communication engineering. This paper studies how to improve equipment operating efficiency, reduce the probability of leakage problems, and improve the quality of information transmission. Combining the principle of equipment anti-interference in electronic information and communication engineering, the author studies the related causes of equipment anti-interference problems, how to deal with transmission interference problems, how to deal with external environment and receiving interference problems. In addition, the author also proposed preventive measures against the above problems and countermeasures for the integration of technical work. The purpose of this article is to improve the operational stability of electronic information and communication engineering equipment and improve the anti-interference ability of the equipment.
Co-frequency signal interference detection based on multiple antennas and multiple channels
Authors: Shuai Jianli , Wang Zuo , Yang Peng
Published: January 2021

Co-frequency signal interference detection plays an absolute role in eliminating same-frequency interference. Eliminating same-frequency interference can improve signal-to-noise ratio and reduce communication errors. For an uncoded multi-antenna multi-channel system with Ni
transmitting antennas and Nj
receiving antennas, the algorithm is optimized on the basis of the QRD-M algorithm, and a depth-first QRD-M algorithm based on single-layer ML (ML-1 -IQRM algorithm), compared the performance of the ML-1-IQRM algorithm with the original QRD-M algorithm. The experimental results show that the ML-1-IQRM algorithm can better detect the interference of the same frequency signal.
Electromagnetic Mutual Inductance Coupling Model of Wireless Power Transfer in Oil-gas downhole
Authors: Wang Yuelong , Ding Yingzhi , Bi Lingzhi , Yang JingYi , Li Yizhen
Published: January 2021

According to the wireless power transfer system (WPT) in oil-gas downhole, the structure of the WPT device suitable for the simultaneous existence of oil-water medium in high-temperature and high-pressure environment is put forward by using the principle of electromagnetic induction. Through the analysis of magnetic circuit, the electromagnetic mutual inductance coupling model is established, and the main factors affecting the transmission efficiency are obtained. Based on the model, the system is simulated and verified by experiments, in order to further improve the efficiency of power transfer system.
Underwater magnetic target signal denoising based on modified wavelet decomposition and reconstruction algorithm
Authors: Qin Tao , Cao pingjun , Zhang yuzhu , Liu zhanxin , Chen zhengxiang , Zhang xuebin , Dou Ke , Dong Hao
Published: January 2021

Noise reduction is crucial for magnetic anomaly signal detection of underwater ferromagnetic target. Modified wavelet decomposition and reconstruction algorithm is proposed to suppress the colored noise and improve the signal to noise ratio. Hamming window is employed to make the preprocessed signal continuous. Evaluation index based on signal-to-noise ratio function is selected, wavelet decomposition and reconstruction algorithm iterates adaptively to select the optimal order of decomposition and reconstruction. The experiment result emphasizes that the signal-to-noise ratio of novel algorithm is 71.6dB. In this particle, we provide a new method to improve signal-to-noise ratio and enhance real-time signal processing for underwater target magnetic anomaly signal detection.
The Design and Investigation of Space Photovoltaic Array Hardware-simulator
Authors: Wang Shuang , Zhang Xiaoming , Gao Xinyu , Tian Yun , He Jing , Liang Quan , Tian Dong , Zhao Ting
Published: January 2021

A hardware part of space photovoltaic array simulation system is designed in this paper, to realize the actual output characteristics of photovoltaic array. In this paper, the design of a PV array emulator (PVAE) is presented. By analyzing the V-I characteristic curve of solar cell given by the previous software, the simulation scheme is developed. Secondly, the control scheme of the proposed emulator based on DC-DC converter is discussed in detail, than the transfer function of the whole system is established, at last the digital controller based on DSP is designed. A prototype 200W PVAE based on full bridge DC-DC converter has been made, the experimental results show the validity of the controller design. The application of the PVAE can greatly shorten the research and design cycle of photovoltaic array power supply system of spacecraft, improve the research efficiency and credibility of research results.
Identifying Influential Nodes in Complex Networks Based on Local and Global Methods
Authors: Mijia Li , Hongquan Wei , Yingle Li , Shuxin Liu
Published: January 2021

Identifying Influential Nodes in complex networks is of great significance in both theory and reality. K-shell decomposition method is a local method which is suitable for increasing scale of complex networks but limited in accuracy because many nodes are partitioned with the same K-shell value. To overcome the coarse result of K-shell, an improved K-shell which considers the number of nodes’ iteration layers and degrees is proposed. Unlike local methods, global methods such as Betweenness Centralities (BC) are accurate but time-consuming. We employed an algorithm framework which combines advantages of both local and global methods where core network is extracted by improved K-shell and then BC is used to quantitatively analyze nodes in the core network. We compare the proposed method with other existing methods on Susceptible-Infective-Removal (SIR) mode. Experiments on three real networks show that the proposed method is more efficient and accurate.
Research on laser Link performance of UAV-based platform based on reverse modulation
Authors: Yang Bo , Huang Guoce , Wang Yequn , Wang Guisheng
Published: January 2021

In order to solve the problem of UAV-based optical communication under the constraints of low load, high transmission rate and low bit error rate, this paper studies the alternative scheme and the possibility of optical communication system based on reverse modulation. Based on the study of atmospheric effect, alignment error, and reverse modulator performance, the light intensity propagation model is constructed. Through MATLAB simulation, it is found that under weak turbulence, the link communication distance can reach 7-12km.Good communication effect when turbulence intensity is below 0.4; Increasing the receiver size can improve the communication chain performance effectively.
The networking performance analysis of wireless broadband communication in electricity system
Authors: Tang Xiaoke , Wang Rui , Wang Yubo , Zhao Dongyan , Zhao Xu , Zhang Yubing
Published: January 2021

HPLC (high speed power line carrier) is widely used in electricity information collection, but because of the large variation of attenuation of power line channel, in some environment, it needs wireless communication as supplement router, the current wireless technology, such as LORA(long range radio), NB-IOT(narrow band internet of thing) are for narrowband which can not be used to form a hybrid network with HPLC. So wireless broadband communication in electric system need to be studied. In this paper, we evaluate the performance of networking under wireless broadband communication with the reference of HPLC standard because there is not an approved standard about wireless broadband communication for electric system currently.
Design and Achievement of Security Mechanism of API Gateway Platform Based on Microservice Architecture
Authors: Dawei Yang , Yang Gao , Wei He , Kai Li
Published: January 2021

To solve the current security problems of the microservice architecture, the security mechanism of the API gateway platform using the microservice platform is designed and implemented. To solve the corresponding security problems, a new API platform security mechanism is designed. In the data transmission, the hybrid encryption algorithm hybridized by encryption algorithm of Rivest Shamir Adleman (RSA) and encryption algorithm of Advanced Encryption Standard (AES) is used for data encryption. An API gateway between the client and the microservice is introduced as the only entrance for users to access the microservice, avoiding the complexity of the client logic caused by the direct communication between the client and the server. After the introduction of the API gateway, the API-level service operation authority can be controlled; the security of the front-end and back-end transmission data is improved without affecting the transmission performance. The algorithm designed takes longer time than the AES encryption algorithm, but shorter than the RSA encryption algorithm, which indicates that the time-consuming of the algorithm designed is acceptable, showing the feasibility of the algorithm. The content can provide an important theoretical basis for the security of API gateway platform of microservice architecture.
Research on Key Technologies of Intelligent Operation Control of Super-large Urban Power Grid Based on Multi-center Structure
Authors: Bin Deng , Ling Zhu , Yingqi Huang , Wei Zhong , Zhenhao Ye , Jun Zhan
Published: January 2021

Under the background of higher and higher requirements of intelligent, reliable, green and efficient operation of power grid, the traditional operation control technology of urban power grid can no longer fully meet the new requirements of integrated operation and intelligent dispatching. The increasing environmental pollution and the gradual shortage of natural resources promote the rapid development of intelligent technology for distribution network dispatching. Traditional urban distribution network management ideas, especially the concept and mode of distribution network dispatching, can no longer adapt to the new situation, and need to be repositioned and studied deeply. In the construction of intelligent distribution network, intelligent control system is a very important part, which has a very positive significance for the overall operation of the power grid. This paper takes the construction of intelligent distribution network dispatching system as the long-term vision, extends the development and application trend of intelligent distribution network dispatching technology, and puts forward ideas on how to construct the concept and key technology of intelligent distribution network dispatching suitable for China's super large cities based on the city multi center structure.
RETRACTED: Research on Improving Computer Teaching Quality in Colleges and Universities in the Context of Big Data
Authors: Hong Wang
Published: January 2021

With the continuous development of information technology, big data has entered all walks of life. As an important part of college education, computer teaching is very significant for enhancing students’ computer application ability and promoting comprehensive development. However, there are still many problems in actual computer teaching in Chinese colleges and universities, and the teaching effect is not ideal. Based on this, this article will discuss the characteristics of big data, analyze the problems in computer teaching in colleges and universities, and propose measures to improve the quality under the big data environment, hoping to have certain reference.
New color image encry, tion algorithm based on double chaos system
Authors: Cun Qiqi , Tong Xiaojun
Published: January 2021

Due to the specific characteristics of a chaotic system described by a set of nonlinear deterministic dynamic equations, encryption based on chaos has high security. Therefore, this paper proposes a very safe and effective new color image encryption algorithm based on double chaos system. First, a true color image is divided into three channels, and under the operation of the control signal, different pseudo-random sequences generated by the Chirikov standard image are selected for XOR operation with the image pixels of a certain channel. Secondly, this paper provides a process of generating replacement boxes using one-dimensionaltial attacks and entropy-based attacks. Therefore, the algorithm has a good encryption effect and has broad application prospects in the field of image encryption.
GUI of Prediction of Gas Emission with Artificial Neural Network
Authors: Chen Daning , Zhang Mengxin , Ling Rong , Zhou Jixian , Gao Wei
Published: January 2021

This paper predicted the GUI of gas emission in mining face with the back propagation neural network (BPNN), the radial basis function neural network (RBFNN) and the general regression neural network (GRNN). By comparing the measured values and the prediction values, the results indicated that the BPNN, GRNN and RBFNN were capable of predicting the gas emission, and the prediction value by using the RBFNN is better than the other methods.
RETRACTED: Prediction of Water Quality based on artificial neural network
Authors: Wu Yingjia , Ling Rong , Zhou Jixian , Zhang Mengxin , Gao Wei
Published: January 2021

In this paper, three types of artificial neural network (back-propagation neural network, radial basis function neural network, and generalized regression neural network) were used to predict the pH values in the evaluation of water quality. Based on the measured data from the Xielugang in Jiaxin with the post-hoc analysis for the c and p values of the prediction, the results showed that the prediction within a year by using the generalized regression neural network has the lowest averaged relative error.
Design and Application of Intelligent Course Selection Algorithm for School
Authors: Qiu Guixiang , Liu Zhixu , Sun Yuye
Published: January 2021

Course supermarkets are emerging in many schools in China. Therefore, choosing the right courses has become a practical problem for many students. One of the primary concerns of students is to earn enough credits in a particular time limit. In this paper, we study the problem of credits maximization and evaluate the accuracy and efficiency of three different algorithms: greedy method, search method, and dynamic programming. Finally, we propose a practical implementation of the course selection algorithm that would provide new ideas for students to choose courses and suggestions for schools to set up online curriculums and course selection models.
Research on energy-saving algorithm of wireless sensor network based on penalty error matrix
Authors: Zhang Ping , Liu Meiqing , Kai SU , Han Shuhuan , Chen Wei
Published: January 2021

Taking into account this problems of large data volume, high frequency, and fast energy consumption in data transmission and reception of wireless sensor networks, an energy-saving algorithm based on a penalty error matrix is adopted to reduce network energy consumption. By introducing a penalty error matrix in the adaptive cubic exponential smoothing algorithm, using the principle of the minimum sum of squares of error to track the time series in real time, adjusting and obtaining the optimal smoothing coefficient in time, and it has strong adaptability to data with a large fluctuation range. The MATLAB simulation experiment results show that when the time slot range is 1500, compared with the traditional cubic exponential smoothing algorithm and the adaptive cubic exponential smoothing algorithm, the energy saving effect and prediction accuracy of this algorithm are significantly improved.
A DOA estimation algorithm based on greedy recovery under the condition of array element failure
Authors: Su Peilin , Chen Fuhu
Published: January 2021

Aiming at the DOA estimation when some elements in the hydrophone array fail, the conventional beamforming algorithm is not effective in estimating the direction of arrival. This paper proposes a beamforming algorithm based on greedy recovery. The ideal conditions and After the estimation effect under the failure condition of the array element, the detection performance of the method is compared and analyzed by simulation. The results show that when the failure ratio of the array element reaches 70% or more, the method always keeps the effective identification of the direction of arrival, and has better detection performance and tolerance than traditional algorithms.
The Influence of ISI and an Improved Algorithm of Channel Estimation in the Chirp System
Authors: Zhao Nan , Zhao Dongyan , Wang Yubo , Tang Xiaoke , Zhao Xu , Zhang Yubing , Liu Jiadi
Published: January 2021

Chirp signal is widely used in communication, radar, sonar and ultrasonic systems. The impulse response of channel must be estimated in PSK chirp spread spectrum modulation systems which is a chirp signal multiplied by the PSK modulated signal. Due to the influence of filters and multipath channel, the received signal of current symbol will be affected by the interference of the previous symbol and the next symbol, the interference which is called inter-symbol interference (ISI) can degrade the performance of channel estimation and demodulation. In this paper, based on BPSK chirp spread spectrum modulation system, we describe the received model, the channel estimation based on FFT and channel estimation of matched filtering, analyze the impacts of ISI on channel estimation. And we simulate the MSE of channel estimation and the simulation results are consistent with the analysis, then an improved method of channel estimation is proposed based on the analysis of the impact of ISI on channel estimation.
Network Situation Assessment of Host Node Based on Improved D-S Evidence Theory
Authors: He Liangyuan , Wan Tao , Zhang Chuanlin , Xia Fei , Wang Sheng , Wang Yajie
Published: January 2021

In recent years, network security has become a hot spot of social concern. In order to avoid dependence on network training, improved D-S evidence theory is applied to the situation assessment of host. The fuzzy function is adopted to generate the BPA of the corresponding feature, and the weighting matrix is added to handle conflict evidences in the fusion process. Finally, the situation level of the host node is obtained. The effectiveness and feasibility of the method is proved by analyses of examples.
Mobile Node Design of Indoor Positioning System Based on Bluetooth and LoRa Network
Authors: Wang Wenlong , Zang Chunhua , Chen Zilong , Liu Shuai
Published: January 2021

This paper introduces an indoor positioning system based on LoRa and Bluetooth network. The system uses LoRa communication protocol for network communication, and uses Bluetooth technology to locate the mobile node in the indoor area. The positioning data is transmitted through LoRa network to realize real-time accurate positioning in a large area. The system is composed of mobile nodes, Bluetooth beacons, LoRa gateway, etc., which has low power consumption and low cost, flexible deployment, high performance and other features, can be widely used in large industrial parks that need to locate personnel and equipment and all other indoor positioning scenarios.
Design of Internet of Vehicles Authentication Scheme Based on Blockchain
Authors: Mao Chen , Xie Kaiyu , Gao Lei , Wan Mingjiang , Liu Shuxian
Published: January 2021

While the Internet of Vehicles brings convenience to people, it also brings new challenges to vehicle safety. In view of the security problems of data destruction, replay, counterfeiting and monitoring in the information exchange of the Internet of Vehicles, the article aims to improve the security of identity authentication of the Internet of Vehicles, and relies on the framework of Hyperledger Fabric and divides it according to the characteristics of its modular components. Different participating nodes have designed a model of Internet of Vehicles application service platform based on Hyperledger Fabric based on this; using the decentralization of blockchain technology and the non-tamperable characteristics of the data to endorse the vehicle's identity authentication information as a substitute. The traditional CA certification center combines the blockchain technology with the traditional identity authentication technology based on cryptography, and proposes a solution for the Internet of Vehicles identity authentication based on the blockchain technology. Finally, the article makes a security analysis of the scheme, which shows the effectiveness of the method.
Efficient Fully homomorphic encryption scheme using Ring-LWE
Authors: Xin Dan , Ji Jingzhou , Jing Feng , Gao Mei , Xue Bin
Published: January 2021

Data can be stored and processed in an encrypted format using fully homomorphic encryption, which makes cloud computing provider can process data well without even knowing data information. However, most existing homomorphic encryption schemes based on ring learning with errors, focus on the special classes of rings, such as power-of-two cyclotomic rings, which significantly limits its application efficiency in cloud computing. Therefore, in this letter, to solve this problem above, an efficient fully homomorphic encryption scheme is proposed based on ring learning with errors in arbitrary cyclotomic rings. Particularly, a “somewhat homomorphic encryption” scheme is firstly proposed based on ring learning with errors. A novel fully homomorphic encryption scheme is further presented using key-switching. With theoretical and experimental verification, the proposed scheme has advantage of high efficiency of encryption and decryption. The security of our scheme strictly reduces to hardness of decision ring learning with errors problem in the random oracle model.