bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated thermoacoustic and ultrasound imaging based on the combination of a hollow concave transducer array and a linear transducer array
Authors: Wang Xue , Huang Lin , Chi Zihui , Jiang Huabei
Published: May 2021

To integrate the high resolution of ultrasound imaging (UI) and the high tissue specificity of thermoacoustic imaging (TAI) and to achieve an easy and precise co-registration of the two different imaging modalities, we present and demonstrate a hybrid thermoacoustic and ultrasound (TA/US) imaging system based on the combination of a novel hollow concave array and a commercial linear array. This TA/US imaging system can provide enhanced imaging of both tissues’ mechanical and dielectric properties. We verified the effective imaging performance of the hybrid TA/US system using tissue phantom experiments. In vivo TA/US imaging of the wrist and foot in healthy volunteers was also demonstrated using the hybrid system. This hollow concave array provided enhanced imaging performance for TAI because of its wide angular coverage with an optimal center frequency, showing a large effective imaging field of view (FOV) and improved images with high contrast and superior quality. Compared with stand-alone UI or TAI, the hybrid TA/US imaging presented more complete tissue anatomical structures, like skin, muscles, tendons, blood vessels, and bones for possible human disease diagnosis, although the US image quality using the hybrid system was slightly lower because the distance between the tissue and commercial ultrasound array was not ideal. This study suggests that the hybrid TA/US imaging approach has the potential to become a clinical tool for diagnosis of diseases in the wrist and foot.
Superconducting single-photon detector with a system efficiency of 93% operated in a 2.4 K space-application-compatible cryocooler
Authors: Hu Peng , Ma Yuexue , Li Hao , Liu Ziyao , Yu Huiqin , Quan Jia , Xiao You , You Lixing , Liu Yanjie , Liang Jingtao , Wang Zhen
Published: May 2021

We report herein the development of a superconducting nanowire single-photon detector (SNSPD) that uses a hybrid cryocooler compatible with space applications. The hybrid cryocooler incorporates a two-stage high-frequency pulse-tube cryocooler and a Joule–Thomson loop, which produces a minimum temperature of 2.2 K. The SNSPD with the structure of sandwiched nanowires integrated in the cryocooler shows a maximum detection efficiency of 93% at 1550 nm, which makes it promising for deep-space communications and quantum information applications.
Numerical modeling and simulation for laser beam welding of ultrafine-grained aluminium
Authors: Lazov Lyubomir , Teirumnieks Edmunds , Draganov Ivo , Angelov Nikolay
Published: May 2021

Laser beam welding of aluminium offers huge potential for a wide variety of welding of different thickness parts with the method of thermal conductivity due to the relatively high difference between melting temperature and evaporation. However, due to the high melting temperature and good thermal conductivity of this light metal, the temperature gradients during the welding process are usually high, causing residual stresses in the weld, which can lead to undesirable deterioration of the weld pool properties and the quality of the process. Physical modelling and simulations of the laser welding process are powerful tools for gaining a fundamental understanding of the technological process. They are also a suitable tool for preliminary assessment of the intervals in which the real preliminary experiments for process optimization should take place. This work is devoted to the numerical modelling of the process of welding ultrafine-grained aluminium using a fibre laser. A three-dimensional model of the welding process was created, using the finite element method implemented in the program ABAQUS. The temperature fields at depth z and on the surface x, y in the welded samples is determined. The temperature change as a function of time for different coordinates of the weld is also analysed. During numerical calculations, the power, machining speed and diameter of the workplace are variable. The obtained results are compared with real experiments conducted in the laboratory by other researchers.
Multicolor optomechanically induced transparency in a distant nano-electro-optomechanical system assisted by two-level atomic ensemble
Authors: Pan Guixia , Xiao Ruijie , Chen Huajun , Gao Juan
Published: May 2021

We investigate the multicolor optomechanically induced transparency (OMIT) of a nano-electro-optomechanical system with two-level atomic ensemble. The system consists of two distant cavities and two charged mechanical resonators coupled via the Coulomb interaction. The focus of our study is on the number of the OMIT windows, which can be manipulated by the coupling strength between the system components. Also, the four transparency windows can be observed from the output probe field. When some coupling strengths disappear, the number of transparent windows decreases. Furthermore, the number and the width of the transparent windows can be controlled by the coherent interactions between the optical mode and the mechanical mode, or between the optical mode and the atoms, or between the two optical modes, or controlled by the Coulomb coupling between the two charged mechanical modes. Our approach is feasible for phonon storage, which will have the great potential applications for quantum information processing.
The binding of bovine serum albumin with dye molecules at different pH values. Fluorescence lifetime studies
Authors: Gorodnichev E S , Kuleshova A A , Volkova O I , Saletsky A M
Published: May 2021

The spectral and kinetic characteristics of the fluorescence of the solutions of bovine serum albumin (BSA) and the dyes (N-(p-carboxyphenyl) imide of 4-(dimethylamino) naphthalic acid (CAPIDAN) and Bengal Rose (BR)) in BSA solutions were studied at 3.5 < pH < 8.0. It was discovered that the attenuation of CAPIDAN fluorescence at the studied pH region is described by the sum of three components (with the values of time constants: 6.0 ns < τ
1 < 8.5 ns, 1.8 ns < τ
2 < 2.2 ns, 0.4 ns < τ
3 < 0.6 ns), while it is described by two components for BR (0.33 ns < τ
1 < 0.4 ns, 2.0 ns < τ
2 < 3.1 ns). It is shown that the mechanisms of the binding of dye and protein molecules are different for CAPIDAN and BR. The binding process of CAPIDAN and BSA is regulated by the conformation of the binding center. The interaction between the BR and BSA molecules is electrostatic, the magnitude of this interaction is determined by the ratio of the charges of the dye and protein molecules. The dependence of the wavelength of the maximum of the spectra, the intensity of the glow and the efficiency of quenching of the fluorescence of the molecules of the studied dyes on the pH is analyzed. The parameters dμ, which characterizes the change in the dipole moment of the fluorophore during its excitation, and η, which characterizes the change in the intensity at the maximum of the fluorescence spectrum at different pH solutions, were also determined for BR. The following ratios were determined at the studied pH range:

d
μ
>
1

and η < 1. The changes of the characteristics of the stationary fluorescence of the studied dyes at different pH of BSA solutions confirm the mechanisms of the binding between CAPIDAN or BR molecules and protein molecules.
Exploration of magnetic field generation of

H32+

by direct ionization and coherent resonant excitation*
Authors: Yang Zhi-Jie , Xu Qing-Yun , He Yong-Lin , Liu Xue-Shen , Guo Jing
Published: May 2021

Coherent electronic dynamics are of great significance in photo-induced processes and molecular magnetism. We theoretically investigate electronic dynamics of triatomic molecule

H
3

2
+

by circularly polarized pulses, including electron density distributions, induced electronic currents, and ultrafast magnetic field generation. By comparing the results of the coherent resonant excitation and direct ionization, we found that for the coherent resonant excitation, the electron is localized and the coherent electron wave packet moves periodically between three protons, which can be attributed to the coherent superposition of the ground A′ state and excited E+ state. Whereas, for the direct single-photon ionization, the induced electronic currents mainly come from the free electron in the continuum state. It is found that there are differences in the intensity, phase, and frequency of the induced current and the generated magnetic field. The scheme allows one to control the induced electronic current and the ultrafast magnetic field generation.
Quantum exceptional points of non-Hermitian Hamiltonian and Liouvillian in dissipative quantum Rabi model*
Authors: Ou Xianfeng , Huang Jiahao , Lee Chaohong
Published: May 2021

The open quantum system can be described by either a Lindblad master equation or a non-Hermitian Hamiltonian (NHH). However, these two descriptions usually have different exceptional points (EPs), associated with the degeneracies in the open quantum system. Here, considering a dissipative quantum Rabi model, we study the spectral features of EPs in these two descriptions and explore their connections. We find that, although the EPs in these two descriptions are usually different, the EPs of NHH will be consistent with the EPs of master equation in the weak coupling regime. Further, we find that the quantum Fisher information (QFI), which measures the statistical distance between quantum states, can be used as a signature for the appearance of EPs. Our study may give a theoretical guidance for exploring the properties of EPs in open quantum systems.
Design of the cryogenic system of the wideband phased array feed for QTT
Authors: Ma Jun , Wu Yang , Xiao Song , Niu Sheng-Pu , Wang Kai
Published: May 2021

Phased array feeds (PAFs), which illuminate the dish with digitally synthesized beams instead of separated horns, provide the capability for wider and continuous field-of-view surveys. As a promising technology for next generation radio telescopes, PAFs will provide the Qi Tai Telescope (QTT), which will be next world-class fully steerable radio telescope, an opportunity of reaching several cutting-edge science goals. This paper presents a brief introduction of the wideband PAF for QTT, and the detailed design and simulation of the cryogenic system. Based on this design, a scaled prototype of the spherical vacuum window, which is the key part of the cryogenic system, has been built and the performance is verified.
Precision of the Chinese Space Station Telescope (CSST) stellar radial velocities
Authors: Sun Yang , Deng Ding-Shan , Yuan Hai-Bo
Published: May 2021

The Chinese Space Station Telescope (CSST) spectroscopic survey plans to deliver high-quality low-resolution (R > 200) slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag, covering a large survey area (17 500 deg2) and a wide wavelength range (255–1000 nm by three bands GU, GV, and GI). In this work, we use empirical spectra of the Next Generation Spectral Library to simulate the CSST stellar spectra at R = 250, and investigate their capabilities in measuring radial velocities. We find that velocity uncertainties depend strongly on effective temperature, weakly on metallicity for only FGK stars, and hardly on surface gravity. It is possible to deliver stellar radial velocities to a precision of about 3 km s−1 for AFGKM stars, and about 10 km s−1 for OB stars, at signal-to-noise ratio (SNR) of 100. Velocity uncertainties using single GU/GV/GI band spectra are also explored. Given the same SNR, the GU band performs best, the GV band the second best, and then the GI band. The effects of spectral normalization and the imperfect template on velocity measurements are investigated and found to be very weak. The uncertainties caused by wavelength calibration are considered and found to be moderate. Given the possible precision of radial velocities, the CSST spectroscopic survey can enable interesting science such as searching for hyper-velocity stars. Limitations of our results are also discussed.
Proactive Management of Information Processes in the Industrial Internet
Authors: Sokolov B.V. , Potryasaev S.A. , Yusupov R.M.
Published: May 2021

The paper presents the scientific and practical foundations of the developed applied theory of proactive control of information processes in the industrial Internet based on cloud and fog computing. The main scientific contribution of the research results is that modern informatics, thanks to the developed theory, is enriched with the methodology and methodological support developed in classical cybernetics and neocybernetics. The paper shows the main elements of this theory, analyzes the possible ways of its development and practical use.
Optimal Estimation Using Deep Neural Networks Applied to Navigation and Motion Control
Authors: Amosov O.S. , Amosova S.G.
Published: May 2021

The critical analysis is given concerning the current state of using deep neural networks with convolutional and recurrent layers, a recurrent network of Long Short-Term Memory, Gated Recurrent Units for estimation tasks in relation to navigation and motion control. A comparison of neural network and traditional methods is given for understanding and explaining their functioning. The differences, advantages and disadvantages of deep neural networks in relation to solving estimation problems are revealed. The possibility of machine training with reinforcement is analyzed for estimation tasks in navigation and motion control in real time. The prospects of using neural networks in the processing of navigation data, as well as for the tasks of adaptive estimation and trajectory tracking, are formulated.
State observers as a means for estimating derivatives of deterministic signals
Authors: Kokunko Yu.G. , Antipov A.S. , Krasnova S.A.
Published: May 2021

To estimate the derivatives of a deterministic signal arriving in real time, a state observer is introduced, built as a replica of the virtual canonical model with an unknown bounded input. The results of a comparative analysis of observers with linear and piecewise linear corrective actions are presented, which are confirmed by the results of numerical modeling for piecewise differentiable composite function. Its derivatives have jump discontinuity points at the moments when the form of the function changes. It is shown that at these moments the observer variables with linear corrective actions with high gains have large surges, which increase by an order of magnitude with an increase in the order of the estimated derivative. Observers with bounded piecewise linear corrective actions do not have these problems and are recommended for use in practical applications.
Comparing underwater vehicle positioning algorithms using single-beacon navigation
Authors: Toropov A. B. , Loparev A. V. , Pelevin A. E.
Published: May 2021

Comparative analysis of two algorithms for underwater vehicle positioning using measurements of range to a drifting buoy and radial velocity is carried out. The algorithms based on building location contours and polynomial filtering are considered. Invalid data rate and radial RMS position error are analyzed to compare the algorithms. Based on the analysis made, the polynomial filtering algorithm is accepted as preferable.
Delay-compensating visual positioning of the mobile robot
Authors: Sevostyanov R.A.
Published: May 2021

The paper considers the task of the automatic positioning of the mobile robot in front of the external visual marker in the case of the presence of the transport delay in the control channel. As a basic regulator without the delay compensation we use mixed approach based on the visual servoing method and a special multipurpose control structure which is capable of taking into account a set of requirements to the controlled dynamics. To compensate the delay we apply the modification of the basic regulator which keeps the original transfer matrix. We also demonstrate the efficiency of the proposed approach by the results of the experiments with the computer model.
Optimal control in the New Keynesian model with monetary and fiscal policy interactions
Authors: Alexeeva T A , Kuznetsov N V , Mokaev T N , Polshchikova I A
Published: May 2021

Dynamics of the New Keynesian model in continuous time with the Rotemberg pricing mechanism is considered within a framework of an optimal control problem. Various regimes of monetary and fiscal policy (‘active’ and ‘passive’) can lead to unstable dynamics in the economy. Parameters of the Taylor rules for both monetary and fiscal policies determine conditions for local equilibrium determinacy. Mapping out the ranges of the Taylor coefficient values where local determinacy cannot be obtained allows to control the economic system by controlling these parameters.
Asymptotic behavior of second-order multiagent systems with fixed configuration
Authors: Agaev R.P.
Published: May 2021

Second-order protocols for consensus and convergence of agent’s trajectories to a fixed configuration are investigated. It is proved that the asymptotic behavior of the second-order system is uniquely determined by the eigenprojection of the Laplacian matrix of the communication digraph. The presented protocol and the corresponding expression for the asymptotic behavior are generalizations of the protocols for simpler cases.
Synthesis of the “second signaling system” of the regulator based on the large deviations principle
Authors: Dubovik Sergey A
Published: May 2021

A stochastic dynamic system is considered, for which a decision-making system is built over the stabilization loop, an analogue of the second signaling system. For this purpose, the principle of large deviations and the theory of optimal control are used.
Optimization of the manned aircraft pitch angle control loop with actuator rate limitation and nonlinear correction
Authors: Zaitceva Iuliia , Andrievsky Boris
Published: May 2021

In the paper a flight control system for a piloted aircraft on the pitch angle is considered, taking into account the rate saturation of the aircraft controlling surface. To prevent occurrence of the non-linear pilot-involved oscillations (PIO), a nonlinear correcting device is introduced into the control loop. On the basis of the pilot’s adaptation to control tasks variations, his/her mathematical model parameters are optimized and the choice of the nonlinear correcting device parameters is proposed. The sensitivity functions of the non-linear system are calculated for harmonic and square-wave reference signals. The results of the optimized system simulations are presented demonstrating good performance of the closed-loop system with nonlinear correction.
The development of Lyapunov direct method in application to synchronization systems
Authors: Smirnova Vera B , Proskurnikov Anton V , Utina Natalia V
Published: May 2021

The paper is devoted to asymptotic behavior of synchronization systems, i.e. Lur’e–type systems with periodic nonlinearities and infinite sets of equilibrum. This class of systems can not be efficiently investigated by standard Lyapunov functions. That is why for synchronization systems several new methods have been elaborated in the framework of Lyapunov direct method. Two of them: the method of periodic Lyapunov functions and the nonlocal reduction method, proved to be rather efficient. In this paper we combine these two methods and the Kalman-Yakubovich-Popov lemma to obtain new frequency–algebraic criteria ensuring Lagrange stability and the convergence of solutions.
Boundedness Condition for Anisotropic Norm of Linear Discrete Time-invariant Systems with Multiplicative Noise
Authors: Kustov A.Yu. , Timin V.N. , Yurchenkov A.V.
Published: May 2021

In this paper, the anisotropy-based analysis problem for the linear discrete time-invariant system with state-multiplicative noises is considered. The mean anisotropy of stationary input sequence is assumed to be bounded by given nonnegative value. For this setting, the boundedness condition for anisotropic norm of the system is obtained in terms of Riccati equations.
On a Mathematical Model of the Second-Order Measuring Transducer
Authors: Zamyshlyaeva A. A. , Bychkov E. V. , Tsyplenkova O. N. , Sviridyuk G. A.
Published: May 2021

The paper discusses a mathematical model of the second-order measuring transducer, which is based on the Lagrange equation of the second kind. On the basis of the theory of high-order Sobolev-type equations and optimal control of solutions to the Showalter – Sidorov problem, a theorem on the existence of an optimal dynamic measurement is obtained. Second-order sensors such as accelerometers, two-link oscillators and some other systems can be investigated in the framework of this mathematical model.
Optimal measurement problem for semi-linear descriptor system with Showalter–Sidorov condition
Authors: Gavrilova O. V. , Manakova N. A. , Perevozchikova K. V. , Sviridyuk G. A.
Published: May 2021

A semilinear descriptor system with a linear part and a nonlinear term is considered. This system is not resolved with respect to the derivative of the desired vector function. The article describes the optimal measurement problem for the model under study with the Showalter–Sidorov condition. Based on the methods of the theory of dynamic measurements, sufficient conditions for the existence of a solution to the problem of optimal measurement are found.
Convergence of the spline method for solving the optimal dynamic measurement problem
Authors: Keller A.V. , Sagadeeva M.A.
Published: May 2021

The problem of optimal dynamic measurement consists in finding the dynamically distorted input signal by observing the output signal. This problem is solved as an optimal control problem to minimize the difference between the values obtained from the output data and the model values obtained in the course of a computational experiment. It was shown earlier that this problem has a unique solution. For a complex form of the input signal, various numerical methods can be used to find the optimal dynamic measurement. This article suggests to use the spline method in order to solve this problem. Namely, we present the algorithm of this method and show that the solution obtained by the spline method converges to the exact solution of this problem.
Adaptive Control of Rigid Multi-Degree-of-Freedom Nonlinear Mechanical Plants
Authors: Quang Le Hong , Putov V. V. , Sheludko V. N.
Published: May 2021

The paper considers the problems of control synthesis of a rigid multi-degree-of-freedom (multi-DOF) nonlinear mechanical plant under conditions of parametric and functional uncertainty. Developed and investigated adaptive robust control systems are synthesized on the basis of three approaches: based on the method of computed torque, the method of majorizing functions, and also the method of integrator backstepping with modified adaptation algorithms with parametric projection. The results of a comparative study by modeling the designed adaptive systems for the nonlinear mathematical model of a four-degree manipulation arm described by the Lagrange equations are shown.
Extraction of isomorphic subformulas as a tool for logic ontology construction
Authors: Kosovskaya T.
Published: May 2021

A way of constructing a logic ontology for complex structured objects is considered in the paper. The descriptions of such objects are given in the predicate calculus language. An algorithm for extracting subsets of objects with the same properties and establishing their relative position is described. To construct such an ontology, an algorithm for extracting the largest subformula isomorphic to subformulas of all descriptions of objects from the class is used.
Model design as a new socio-cyber-physical systems creating mechanism
Authors: Yurkevich E.V. , Kryukova L. N.
Published: May 2021

The purpose of this work is to consider the methodology of designing intellectual models of cyber-physical social systems that take into account the cybernetic properties of the hardware, software and the human factor specifics of the system developers and users. To ensure customizable solutions, model design process is based on systems analysis. This methodology can be implemented by optimizing the objective tree, which determines the development vector of the model being designed based on their importance; the information tree, which determines the structure of the knowledge base optimized by the cost of resources used; the task tree, which allows optimizing the development of the cyber-physical social systems based on the results of analyzing the criteria of the two trees. Intellectual properties of the model being designed are determined by automating the management of its development vector in accordance with the dynamics of the utility of its specific goals. Due to practical limitations on the amount of resources available, the task is to optimize the plan for creating a cyber-physical social system that maximizes the solution value with limited cost. The choice between more precise algorithms that are not applicable given fuzzy limitations caused by human factor allows solving the problems faster than when using deterministic or heuristic methods.
Development of Stability Control Mechanisms in Neural Network Forecasting Systems
Authors: Miloserdov I. , Miloserdov D.
Published: May 2021

The problem of ensuring the stable functioning of time series forecasting systems based on streaming recurrent neural networks with controlled elements is considered. The mechanisms necessary and sufficient for its maintenance are derived, which involve maintaining the balance of the learning history and modifying the synapse learning rules in order to establish a balance between positive and negative potential. The results of experiments to assess the accuracy of forecasting are presented.
Accuracy improving of pre-trained neural networks by fine tuning
Authors: Konarev D. I. , Gulamov A. A.
Published: May 2021

Methods of accuracy improving of pre-trained networks are discussed. Images of ships are input data for the networks. Networks are built and trained using Keras and TensorFlow machine learning libraries. Fine tuning of previously trained convoluted artificial neural networks for pattern recognition tasks is described. Fine tuning of VGG16 and VGG19 networks is done by using Keras Applications. The accuracy of VGG16 network with fine tuning of the last convolution unit increased from 94.38% to 95.21%. An increase is only 0.83%. The accuracy of VGG19 network with fine tuning of the last convolution unit increased from 92.97% to 96.39%, which is a 3.42% increase.
Features of complementary objects usage in distributed virtual environment
Authors: Shalnev Ilia O.
Published: May 2021

. In this paper, complementary objects design and usage is considered. The presented examples illustrate the programming paradigms necessary for correct usage of complementary objects that are essential in distributed computation systems.
Blockchain-based approach to achieve credible traceability of agricultural product transactions
Authors: Yi Wenlong , Huang Ximeng , Yin Hua , Dai Shiming
Published: May 2021

The traditional traceability system for agricultural product transactions is susceptible to information alteration and damage, which may lead to issues regarding product quality and food safety. And blockchain is a technology that boasts tamper-proofing, complete traceability and time-stamped storage. Considering the above, this study proposes a new blockchain-based approach to the quality management of agricultural products and introduces Solidity-based prototype smart contracts for agricultural product transactions. Test results show that the new traceability system can offer good performance in terms of data upload and block response time. The method proposed in this paper can be used as a solution for quality management of agricultural product that boasts whole process transparency, full-link reliability and joint supervision by all nodes in the system.
Smart home security management
Authors: Tatarnikova T. , Sovetov B.
Published: May 2021

The problem of ensuring the information security of the smart home is discussed, the main vulnerabilities and the consequences they can cause are listed. Mechanisms for protecting information in the smart home system based on the characteristics of consumed resources: energy, time, computing power, are proposed. A description of the smart home system assembled model is presented, and consumed resources characteristics allowing reasonable choice of the method for protecting information transmitted by devices over open channels are measured by using this model.
Investigation of the method of determination of password resistance to brute force based on an artificial neural network
Authors: Izrailov K. E. , Zhukovskaya P. E. , Kurta P. A. , Chechulin A. A.
Published: May 2021

The paper deals with a topical subject of information system access security through development of a polling system aimed at forecasting the resistance of the user’s passwords against brute force. A method of development of such a system, which is based on computer-aided learning, is suggested. This method is based on the following hypothesis: “Social and psychological features of the password system users have a bearing on the complexity of created passwords.” The method is elaborated in the form of the following 6 steps: development of a group of questions which reflect the preferences of the password system user; implementation of a polling system which requests the user’s typical password; selection of a mechanism of independent estimation of password complexity; application of the polling system to generate implicit interrelations of specific features of users and their passwords; development and training of a neural network to solve a regression problem based on the results of the polling system use; and estimation of the neural network by a test set of users. The experiment results are presented in a form of a diagram. The results of the experiment are discussed and conclusions are drawn about the method development.
Analysis of Control Channel Cybersecurity of the Consumer-Grade UAV by the Example of DJI Tello
Authors: Mamchenko M.V.
Published: May 2021

This paper presents the assessment of cybersecurity of the non-industrial unmanned aerial vehicle (UAV; using DJI Tello as an example) wireless control channel, implemented on the basis of Wi-Fi Wireless Local Area Network technology. As a result of the research, a model of an adversary conducting a cyberattack on the UAV communication channel was developed, and scenarios of an intruder’s actions (aimed at taking control of the UAV or disabling it) were considered. Relevant block diagrams of the actions of an adversary were also developed. Based on the results of the analysis, a security strategy is proposed. It provides the maximum possible protection (based on the technical characteristics of the drone) and comprises not only passive protection in the form of setting a tough password, but also active actions –deploying a system to monitor the injections of deauthentication/dissociation frames and/or the creation of duplicate wireless networks.
Design of a direction finder based on the output of parallel hydroacoustic surveillance system
Authors: Melkanovich V.S.
Published: May 2021

The problem of synthesizing a direction finding algorithm based on a sample composed of the output signals of a limited number of channels of a scanning sonar system is considered. The problem is formulated as a search for the maximum of the likelihood function by its lattice representation. Options for using the optimal and quadratic interpolation are considered. The errors of displacement and loss of potential accuracy are estimated depending on sample dimension, angular step of scanning, and on the amount of the target movement within the measurement interval. The advantage of the proposed approach is shown in terms of its potential accuracy compared to the traditional approach to constructing direction finding paths based on Guanella’s technique.
Development of an effective hybrid system for generation and distribution of electric power for autonomous unmanned underwater vehicles
Authors: Kiselev N. , Martynova L.
Published: May 2021

The problem of coordinated operation of a hybrid system for generation and distribution of electric power to provide motion for an underwater vehicle is addressed. The architecture of a multi-agent vehicle system is chosen, the optimum distribution of consumers to electric lines is defined, effective switching of consumers between electric lines, with due regard to the functional and non-functional requirements for the system, is developed.
Artificial intelligence in technical diagnostics in the example of a marine auxiliary diesel engine
Authors: Kolpakov V. E.
Published: May 2021

The necessity of improving methods for determining the technical condition of ship power plants is justified, using the example of an auxiliary engine. A brief analysis of the most common systems of self-diagnostics is given. Features of development and use of artificial intelligence for diagnostics of internal combustion engines are described. The algorithm for conducting experimental studies to obtain a sample of diagnostic features is incorrect. The characteristics of synthesized neural networks are given and the accuracy of determining the technical state is estimated.
Research on Urban Road Traffic Accident Characteristics and Countermeasures: A Case Study of Ningbo City
Authors: Xiong Xiaoxia , Zhang Shuichao , Shen Yujie
Published: May 2021

Current road traffic safety situation is still challenging globally and needs continuous public attention. Exploring the characteristics of road traffic accidents could improve the understanding of accident causation mechanism and help develop countermeasures to reduce the accident occurrences. The paper first explores the general characteristics of urban road traffic accidents from the perspectives of temporal, spatial, and personal distributions. Random Forest (RF) Model is then utilized to identify important features affecting the occurrence of traffic accidents. Accordant countermeasures are finally discussed and proposed.
Research on Blood Supply Chain Optimization under Supply Unreliable and Stochastic Demand
Authors: Zhao Kangli , Xiang Changcheng , Chen Yan
Published: May 2021

This paper explores the problem of blood supply chain optimization under the double uncertainty of supply and demand, considers the impact of supply unreliability, demand difference and different inventory allocation methods on supply chain performance, and constructs a mathematical model of multi-cycle operation of blood supply chain. The blood supply chain system expiration rate under different strategy combinations was obtained through computer simulation optimization. Through the analysis of the results, it is found that the supply fluctuation has a greater impact on the performance of the supply chain. The performance adjustment effect of the distribution mode itself is small. Expiration due to short-term demand fluctuations is greater than the expiration rate caused by long-term demand fluctuations. Proposed a blood supply chain operation strategy for different supply environments.
Entrance Location Planning of HOV Lanes in Multi-lane Highway Considering System and HOV Lane State
Authors: Zang Guangzhi
Published: May 2021

The high-occupancy vehicle (HOV) lane is an effective traffic demand management that encourages carpooling. In this study, we examine entrance location planning of HOV lanes. A highway commuting system containing HOV lanes is proposed. Commuters make travel choices based on the principle of minimum commuting time, i.e., the system is in the user equilibrium state. By planning the HOV lanes’ entrance location, the manager indirectly influences the commuters’ travel choices, thus achieving the predetermined management goals. In this study, an optimization model is developed where the decision variable is the entrance location of the HOV lane, and the conditional constraint of user equilibrium is satisfied. The objective function is a weighted average of a system state indicator and an HOV lane state one. Numerical examples show that the proposed method solves the location planning problem of the HOV lane entrance. The quantitative results reveal that the system congestion is relieved when the HOV lane entrance is close to the city center, and the traffic condition of the HOV lane is improved when the entrance is close to the city’s edge.
Cause Analysis of Railway Traffic Accidents Based on Random Forest
Authors: Wang Minxuan , Liu Di
Published: May 2021

With the rapid growth of the railway operation scale, all kinds of railway traffic accidents happen from time to time, so it is great significant to accurately identify the main influencing factors and their influence degree. In this paper, random forest model is proposed to analyze the cause of railway traffic accidents. Considering people, equipment, environment and other aspects, 11 influencing factors were extracted from 491 accident data. The influence degree of different factors on the severity of the accident is judged through variable importance measures of the random forest. On the basis of this, some suggestions are put forward for raising the safety level of railway transportation. The results show that the random forest model is accurate for analyzing the causes of railway traffic accidents, which can provide decision support for railway transportation safety management.
Research on Selection of General Aviation Rescue Airports
Authors: Hu Bin , Pan Fang , Zhang Yunfei
Published: May 2021

Considering the complex factors affecting rescue in natural disaster-prone areas in China and the high efficiency of general aviation rescue, this paper combines a hierarchical analysis model and a P-median model to establish a two-stage hierarchical selection. A greedy take-away heuristic algorithm is proposed to combine the qualitative and quantitative analysis of the airport selection method. Finally, the Longmenshan earthquake zone was selected for analysis to verify the practicability of the method.
Prediction of the Quantity of Boxed Meals Preparation by High-Speed Train Based on ELM
Authors: Zhou Feifei , Yang Hao , Wang Jiahe , Sun Xi’an , Wu Xu
Published: May 2021

Meal service is an important part of the railway transportation service, and when preparing the number of boxed meals before departure, the train must meet the needs of the train passengers for self-catering and food service. The demand of meals avoids causing too much waste. Extreme learning machine has the characteristics of fast learning speed and generalization ability, and has a wide range of applications in neural network prediction, this paper from the train perspective, by applying and improving the ELM model and using some of the high-speed train data from the Beijing-Qingdao section for model training. A prediction error analysis was performed to verify the reasonableness and feasibility of the model for the prediction of boxed meals.
Third-party Payment Services Selection for Logistics Public Information Platforms
Authors: Shi Xianlian , Deng Jianxin , Su Xiaogen , Cao Chenying
Published: May 2021

The payment mode has important effects on business transactions. This paper focuses on decision-making research on third-party payment services selection for logistics information platforms (LPIPs). From the point of view of technology adoption and LPIPs, six selection criteria of third-party payment services were proposed based on UTAUT model. An optimal decision-making approach measured by these criteria was put forward based on the multi-attribute decision-making theory. The final criteria weights were adjusted by the initial individuals separately obtained by the relative comparison method and entropy evaluation method. And the final evaluation of all was obtained by weighted averaging. An illustrative case was carried out based on the former method. It is indicated that the proposed decision-making method is effective and could well distinguish different third-party payment software for LPIPs in quantitative way.
Calculation and Analysis of Gauges for Suspension-type Monorail Vehicle
Authors: Zhan Shen , Chen Bingyan , Zou Jiancai , Qu Wenqiang , Wang Xiaojun
Published: May 2021

The differences between two types of monorail vehicles are compared, and the configuration of suspension-type monorail vehicle is introduced. The vertical and lateral displacements of carbody under two running conditions are derived from the corresponding directional motions, which is the basis on calculating the vehicle gauge for suspension-type monorail vehicles. A program is written to calculate the displacement and then the results are transformed into vehicle gauges. The validity of the derivation formulas is verified.
Drugs Sale Forecasting Based on SVR Integrated Promotion Factors
Authors: Liu Yang , Yang Xiao , Zhu Cuiling , Meng Jie
Published: May 2021

In order to improve the inventory management level of pharmaceutical chain enterprise, drug sales forecasting is needed. Using machine learning SVR model, we forecast the drugs sale amount with a relatively high accuracy. Suppose the sales amount is influenced by promotion strategy, we integrated the promotion factors into the SVR model. Experimental result of drug sales prediction on the real sales data of a large chain drug company S shows that the SVR algorithm integrated with promotion factors get the accuracy rate of 91% and the algorithm can greatly improve the drug sales prediction results compared with traditional time series model.
A high resolution and high detection efficiency depth-encoding detector for brain positron emission tomography based on a 0.75 mm pitch scintillator array
Authors: Du J. , Cherry S.R.
Published: May 2021

The quantitative accuracy and precision of brain positron emission tomography (PET) studies can be considerably improved using dedicated brain PET scanners with a uniform high resolution and a high sensitivity across the brain volume. One approach to building such a system is to construct the PET scanner using depth-of-interaction (DOI) encoding detectors with finely segmented and thick crystal arrays. In this paper, the performance of a DOI PET detector based on two 16 × 16 arrays of 2 × 2 mm^2 SiPMs coupled to both ends of a 44 × 44 array of 0.69 × 0.69 × 30 mm3 polished LYSO crystals was evaluated at different temperatures (-9∘C, 0∘C, 10∘C, and 20∘C) for brain PET applications. The pitch size of the LYSO array is 0.75 mm. The flood histograms show that all the crystal elements in the LYSO array can be resolved except some edge crystals, due to the limited light sharing. The average energy resolution, average DOI resolution, and average timing resolution across crystal elements are 21.1 ± 3.0%, 3.47 ± 0.17 mm, and 1.38 ± 0.09 ns, respectively, which were obtained at a bias voltage of 56.5 V and a temperature of 0∘C.
Design of sustainable dryland crop rotations require value judgements and efficient trade-offs
Authors: Hochman Zvi , Garcia Javier Navarro , Horan Heidi , Whish Jeremy , Bell Lindsay
Published: May 2021

In agriculture, sustainability is framed as an aspiration to achieve multiple goals including positive production, environmental and social outcomes. These aspirations include: increasing production of nutritious food; minimising risk and maximising resilience in response to climate variability, fluctuating markets and extreme weather events; minimising impacts on global warming by reducing emissions; efficiently using limited resources; minimising negative on-site and off-site impacts; preserving biodiversity on farm and in nature; and achieving positive social outcomes reflected in farmers’ incomes (revenue and profit). Here we used cropping systems simulation to assess multiple (11) sustainability indicators for 26 crop rotations to quantify their sustainability throughout Australia’s subtropical cropping zone. Results were first expressed via a series of maps quantifying the minimal environmental impacts of attributes such as N applied, N leached, runoff and GHG emissions of the 26 crop rotations while identifying the locations of the optimal rotation for each attribute. Inspection of these maps showed that different rotations were optimal, depending on both location and the attribute mapped. This observation demonstrated that an 11-way sustainability win-win across all attributes was not likely to happen anywhere in the cropping zone. However, rotations that minimised environmental impacts were often among the more profitable rotations. A more holistic visualisation of the sustainability of six contrasting sites, using sustainability polygons, confirmed that trade-offs between sustainability indicators are required and highlighted that cropping in different sites is inherently more or less sustainable, regardless of the rotations used. Given that trade-offs between the various sustainability attributes of crop rotations are unavoidable, we plotted trade-off charts to identify which rotations offer an efficient trade-off between profit and other sustainability indicators. We propose that these maps, sustainability polygons and trade-off charts can serve as boundary objects for discussions between stakeholders interested in achieving the sustainable intensification of cropping systems.
Large deviations of currents in diffusions with reflective boundaries
Authors: Mallmin E , du Buisson J , Touchette H
Published: May 2021

We study the large deviations of current-type observables defined for Markov diffusion processes evolving in smooth bounded regions of

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d

with reflections at the boundaries. We derive for these the correct boundary conditions that must be imposed on the spectral problem associated with the scaled cumulant generating function, which gives, by Legendre transform, the rate function characterizing the likelihood of current fluctuations. Two methods for obtaining the boundary conditions are presented, based on the diffusive limit of random walks and on the Feynman–Kac equation underlying the evolution of generating functions. Our results generalize recent works on density-type observables, and are illustrated for an N-particle single-file diffusion on a ring, which can be mapped to a reflected N-dimensional diffusion.
The Multifractal Characteristics of Seismic Activities in China
Authors: Xu Linfeng , Chen Jiemin , Liu Zhixin , Liu Yan , Tian Jiawei
Published: May 2021

In recent years, with the frequent occurrence of geological disasters, the prediction and analysis of earthquakes has gradually become a hot topic. This paper studies the multifractal spatio-temporal characteristics of China seismic energy. The study data derives from the seismic activities in the Mainland China from 1970 to 2013. In this study, it comes to a comprehensive conclusion of spatial and temporal multifractal characteristics of earthquake activities in China. The study area is divided into five regions: The Xinjiang region, the Qinghai-Tibetan Plateau region, the Northern China, the Northeast China and the Southern China. In this study, we analyze the spectrum curves of the seismic releasing energy time series to each region, and compare the differences. Then the differences of the multifractal characteristics in the time dimension can be pointed out based on the curve, and the law of earthquake occurrence is analyzed from the sequence diagrams of time intervals among various tectonic areas. In the spatial dimension, it discrete seismic data points for each region through rectangular square grid at different resolutions as the input, then derive the multifractal spectrum curve of spatial characteristic to each region. By analyzing the multifractal dimension, it explores the similarities and differences of the spatial and temporal characteristics of the earthquake among five regions.