Acta Armamentarii

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2020, 41(3): 0.

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Research on Anti-jamming Performance of M-sequence Pseudo-random Code Phase Modulation Pulse Doppler Fuze

YU Honghai， YAN Xiaopeng， JIA Ruili， LI Ze， WANG Jiantao

2020, 41(3): 417-425. doi:10.3969/j.issn.1000-1093.2020.03.001

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An anti-jamming method for M-sequence pseudo-random code phase-modulation and pulse Doppler combined fuze is proposed to solve the less selectable range and easy crack of pseudo-random sequence of m-sequence pseudo-random code phase-modulation and pulse Doppler combined fuze. The M-sequence pseudo-random code phase modulation and pulse Doppler combined fuze is designed based on the characteristics of M-sequence nonlinearity, which is complex in structure, huge number and difficult to be intercepted and reconstructed. The response expressions of each level in the detection process of fuze are derived theoretically, and the anti-jamming performance of M-sequence pseudo-code phase- modulated pulse Doppler combined fuze is quantitatively calculated by taking the processing gain as an index. The theoretical calculated and experimental results show that the M-sequence pseudo-random code phase-modulation and pulse Doppler combined fuze can further improve its anti-active jamming ability compared with m-sequence. Key

Analysis about the Influences of Different Fuels on the Combustion Stability of a Heavy Duty Diesel Engine

GU Cheng, QIAO Xinyong, HAN Lijun

2020, 41(3): 426-433. doi:10.3969/j.issn.1000-1093.2020.03.002

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In order to reveal the influences of different fuels on the cyclical variation of diesel combustion process, three military diesel fuels A, B, and C were selected as fuels for the bench test under the calibration conditions and the maximum torque conditions. The three-dimensional phase space of the in- cylinder pressure time series was reconstructed. The combustion stability of diesel engine was quantitatively analyzed by using the cyclic fluctuation rate of the combustion parameters, and the average indicated pressure was studied from the return mapping. The results show that the state of cylinder in diesel engine exhibits certain chaotic characteristics. During the combustion process, the pressure in the cylinder is oscillating. Compared with Fuel B and Fuel C, the traces of Fuel A in the combustion stage are relatively dense. The peak pressure fluctuation rate in the combustion stage corresponds to the pressure oscillation region. Under the maximum torque condition, the first two peak pressure fluctuation rates of Fuel A are the lowest, the combustion delay period is the shortest, and the average indicated pressure cycle is the smallest. The combustion stabilities of three diesel fuels are improved with the increase in the rotational speed. Key

Research on the Hydrodynamic Performance of a Double-carriage Amphibious Vehicle Sailing in Still Water

WANG Shaoxin， JIN Guoqing， WANG Han， SUN Rui， LIU He

2020, 41(3): 434-441. doi:10.3969/j.issn.1000-1093.2020.03.003

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In recent years, a double-carriage amphibious vehicle has been developed to improve the carrying capacity of amphibious vehicle. Based on the full-scale model of an amphibious vehicle, the computational fluid dynamics method and the overlapping grid technique are used to establish a numerical simulation model of multi-body motion. Two carriages are connected by a spherical joint with three-dimensional degrees of freedom. The hydrodynamic performances, such as resistance, pitching and heaving motions, of the vehicle under still water condition are calculated, and the effect of spherical joint connection on the vehicle is analyzed. The numerically calculated result is basically consistent with the total resistance of the model towing tank test. The research results show that the hydrodynamic performance of the three-dimensional vehicle can be numerically predicted based on the realizable k-ε turbulence model and multi-body overlapping grid technology. The pitch angle is kept within 1°，and the pitch performance of the amphibious vehicle is excellent during its sailing in still water. Key

Research on Muzzle Disturbances of Gun Barrel with Bore Damage during Firing

SHEN Chao， ZHOU Kedong， HE Lei， LU Ye， LI Junsong

2020, 41(3): 442-450. doi:10.3969/j.issn.1000-1093.2020.03.004

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In order to explore the mechanism of how bore damage leads to the decrease in firing accuracy and the rise in the ratio of elliptical shot holes, eventually leading to the end of a barrel life, the thermo-mechanical coupling finite element analysis (FEA) models of barrels with bore damage at 4 life stages, including undamaged barrel, middle-early life barrel, mid-life barrel, and end-of-life barrel，are established based on barrel life tests. Uniform design method is used to design the simulation test of interior ballistics process influenced by random factors of ammunition. The response values of muzzle disturbances of differently damaged barrels were acquired in the simulation test. The simulated results are in well agreement with the experimental data. The response surface equation for muzzle disturbance for taking ammunition random factors as independent variable and the rules of how ammunition random factors influence the muzzle disturbances of differently damaged barrels are obtained by using the partial least-squares regression method based on cubic B-spline curve and the uniform design-response surface method. The simulated and analyzed results show that the contribution of each ammunition random factor to the muzzle disturbances of differently damaged barrels is unequal. In order to reduce the muzzle disturbances of barrels in its later lifetime, the mass eccentricity of bullet and the initial yield strength of jacket material should be decreased, and the cylindrical diameter and charge weight should be moderate. Key

Research on the Forming Mechanism of Ring Pattern Defects on Inner Wall of Chamber during Precision Radial Forging Process

LIU Jinming， LIU Bing， YANG Chen， REN Qingsong， FAN Lixia

2020, 41(3): 451-459. doi:10.3969/j.issn.1000-1093.2020.03.005

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The forming of barrel chamber is the key and difficult point in the radial forging process. The forming quality of inner wall of chamber is directly related to the accuracy and service life of barrel. The ring pattern on the inner wall is the main forming defect of chamber. The force characteristics and flow conditions of the inner wall of chamber during the radial forging process are analyzed. The forming causes of ring pattern defeact are analyzed from its forming position through finite element analysis and experiment, and the relevant judgment criteria for ring pattern are established. The stress analysis curves of inner wall material were compared with the forging experimental results of barrel. It is found that the generation of ring pattern is related to the instability of inner wall. When the tangential stress component of inner wall exceeds the critical value, the instability wrinkles appear. Further research show that the ring pattern on the inner wall is flattened in the subsequent forging process,and the defect of chamber can be eliminated when the forging ratio of forging section of chamber reaches the critical value. The results show that the tangential compressive stress of inner wall is more than 2 150 MPa during forging process, which leads to the instability of inner wall. When the forging ratio of forging section exceeds 28.5%, the ring pattern on the inner wall can be flattened. Key

Research on Aerodynamic Characteristics of Solid Fuel Ramjet Guided Projectile

ZHANG Ning， SHI Jinguang， MA Yexuan

2020, 41(3): 460-470. doi:10.3969/j.issn.1000-1093.2020.03.006

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In order to study the aerodynamic characteristics of the solid fuel ramjet guided projectile in different ballistic stages, three aerodynamic configurations corresponding to the states of ramjet assisting, climbing flight and gliding control are designed according to the working principle and flight characteristics of projectile. The Renault transition model is used to simulate and numerically calculate the three-dimensional flow field and aerodynamic characteristics of solid fuel ramjet guided projectile. The results show that comparison of the three aerodynamic configurations with the same shape parameters（except for canard and head bus）do not adopt the ramjet of the duck-type layout guided projectile (reference projectile), the lift resistance coefficient is the same; the drag coefficients of punching boost, gliding control, and climbing flight shape under the same conditions are increased by 50.5%,42.9% and 33%, respectively, compared to the reference drag coefficient; the gliding control shape is unfolded due to the duck rudder. The lift coefficient is larger than the other two shapes under the same conditions, and the duck rudder area is limited by the air inlet. The lift coefficient is smaller than that of the reference bomb under the same conditions; and the flow path structure inside the shape has a slight influence on the lift.Key

Numerical Investigation on Evolutionary Characteristics of Muzzle Flow Field of Ballistic Gun during Underwater Submerged Firing

ZHANG Jinghui, YU Yonggang

2020, 41(3): 471-480. doi:10.3969/j.issn.1000-1093.2020.03.007

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An underwater shooting experimental platform was built to research the evolutionary characteristics of muzzle flow field of ballistic gun during underwater submerged firing. The direct photography method was used to capture the whole evolution process of the flow field. The high-speed water column in front of bullet produces the water vapor at the muzzle before the bullet comes out of the bore; the under-expanded gas in the bore flows out after the bullet comes out of the bore, and blends with the water vaporto wrap around the bullet; after the bullet leaves from the muzzle, the gas jet continues to expand, and the head of jet is tapered; the surface of bullet is continuously cavitated to generate supercavitation, and at the same time, a slender air column is left at the tail of bullet. On the basis of experiment, a two-dimensional multi-phase flow model is established to simulate the experimental conditions, in which the fluid volume multiphase flow model, standard k-ε turbulence model, dynamic mesh and user-defined functions technology are used. The results indicate that a complex wave structure containing two bottle-shaped shock waves is formed after the highly under-expanded gunpowder gas exits from the muzzle during underwater submerged firing of ballisitc gun. After the bullet leaves from the muzzle, it accelerates continuously in the muzzle flow field. As the bullet moves away from the flow muzzle flow field, the velocity of bullet is continuously attenuated. Key

Effect of Crystal Structure of High Density Spherical RDX on Safety Performance of PBX

QIN Jinfeng， ZHAO Xue， QIAN Hua， RUI Jiuhou

2020, 41(3): 481-487. doi:10.3969/j.issn.1000-1093.2020.03.008

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The effect of crystal structure of high density spherical RDX on the safety of PBX was studied by molecular dynamics simulation and experiment. The crystal structure of high density spherical RDX was measured by X-ray single crystal diffraction. Then based on the crystal structure data, the safety performances of high density spherical RDX-based PBX and ordinary RDX-based PBX were compared by molecular dynamics simulation. To verify the accuracy of molecular dynamics simulation results, the casting PBX explosives based on high density spherical RDX and ordinary RDX were prepared. The detonator sensitivity and shock wave sensitivity of the casting PBX were tested by using direct detonation method and card separator method. Molecular dynamics simulated and experimental results show that the high density spherical RDX is a monocrystal with few internal defects and spherical shape, and its cell density is 2.6% higher than that of ordinary RDX. The binding energy of high density spherical RDX-based PBX is 289.30 kJ·mol^-1 higher than that of ordinary RDX-based PBX, the cohesive energy density is increased by 0.022 kJ·cm^-3, and the maximum bond length of the induced bond is reduced by 0.02 , indicating that it has lower sensitivity. For the same formula, the detonator sensitivity and shock wave sensitivity of the high density spherical RDX-based PBX are lower than those of the ordinary RDX-based PBX, which is consistent with the results of molecular dynamics simulation. The simulated results were verified to be accurate.Key

Research on Parameters Determination of JWL EOS for Commercial Explosives Based on Underwater Explosion Test

LI Kebin， DONG Xinlong， LI Xiaojie， YAN Honghao， WANG Xiaohong

2020, 41(3): 488-494. doi:10.3969/j.issn.1000-1093.2020.03.009

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In order to conveniently and reliably determine the JWL equation of state (JWL EOS) for detonation products of commercial explosives, an underwater explosion measurement system with a self-developed continuous pressure-conducted velocity probe was designed for measuring the oblique shock wave induced by underwater explosion of cylindrical charge. This system was used to obtain the time history curves of detonation-shock wave front in 3 groups of underwater explosion tests of modified ammonium nitrate / fuel oil (ANFO) charge. The wave fronts were plotted, and other parameters, such as detonation pressure, adiabatic exponent, and included angle of water-gas interface, were calculated by analyzing the underwater explosion of cylindrical charge in two-dimensional steady flow field.Two-dimensional axial-symmetric model of cylindrical charge is built using Autodyn program, and the numerically simulated results of oblique shock wave front and included angle of water-gas interface are compared with the experimental results. The parameters for JWL EOS of modified ANFO are determined by test-and-error method. The simulated results are in agreement with the experimental results. The results show that the error of oblique shock wave front is less than ±5%, and the error of included angle of water-gas interface is less than ±3%. The proposed method is reasonable and reliable for determining the parameters of JWL EOS of large scale commericial explosive. Key

A Signal Demodulation Method for Ultra-tightly Coupled INS/GNSS Navigation System Based on Phase Control

SHEN Shibin, XIE Fei, ZHAO Jing, QIAN Weixing, KANG Guohua, LIU Xixiang

2020, 41(3): 495-506. doi:10.3969/j.issn.1000-1093.2020.03.010

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Satellite navigation is easily affected by interference signals in a complicated environment. The ultra-tightly coupled strapdown inertial navigation system (SINS)/global navigation satellite system (GNSS) navigation system can improve the anti-jamming performance of receiver. On the basis of analyzing the tight integration and ultra-tight integration implementation schemes and BeiDou B1 signal modulation approach, a loop signal demodulation method of ultra-tight integration based on phase control is proposed.The tracking feature of ultra-tightly coupled SINS/GNSS loop signal is analyzed. The navigation perfor-mances of the proposed ultra-tightly coupled method based on phase control and the traditional method based on frequency control in signal jamming and high dynamic environments were test and compared. The test results indicate that the proposed ultra-tightly coupled method has a more stable positioning performance, and can improve 7 dB anti-jamming capability compared with the tightly coupled method.Key

Research on Sea Fog Characteristic Parameters Based on Mesoscale Numerical Atmospheric Model

LONG Yinyu, CHEN Huimin, WANG Fengjie, LU Changping

2020, 41(3): 507-516. doi:10.3969/j.issn.1000-1093.2020.03.011

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In order to study the echo characteristics of sea-skimming laser weapons in the sea fog aerosol environment, it is necessary to further obtain the parameters of sea fog aerosols. Based on the mesoscale numerical atmospheric model WRF, a more intensive η layering was set in the vertical space for the spatial region where the sea fog exists, and the formation process of sea fog was numerically simulated from April 28 to April 29, 2015. The data of the sea fog characteristic parameters, such as the cloud-water mixing ratio and the fog top height, are calculated, and the horizontal visibility data affecting the laser echo is calculated. The results show that the η layer number can be further refined according to the spatial region where the sea fog exists (up to 400 m above sea level), and the characteristic parameters of sea fog can be further refined to improve the accuracy of the acquired data. The visibility parameter can be calculated from the sea fog characteristic parameters, such as cloud-water mixing ratio. The calculating accuracy is affected by the accuracy of the sea fog parameters. Key

Estimation of Sea Clutter Parameters Based on Multiple Characteristic Quantities

HE Yaomin， HE Huafeng， XU Yongzhuang， WANG Yifan， SU Jing

2020, 41(3): 517-525. doi:10.3969/j.issn.1000-1093.2020.03.012

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The sea clutter is studied and analyzed to effectively evaluate the imaging performance of missile-borne synthetic aperture radar (SAR) under different sea conditions. In view of the difficulty in accurately fitting some characteristic quantities, such as peak value and amplitude width of sea clutter amplitude distribution, by traditional parameter estimation method, a parameter estimation method based on multiple characteristic quantities is proposed. The amplitude distribution characteristics and temporal correlation of sea clutter are used to establish a sea clutter model based on SIRP method. Four characteristic quantities, including magnitude with the highest probability, magnitude distribution probability with the highest probability, amplitude width with half of probability, and amplitude critical point with half of probability, which reflect the amplitude distribution of sea clutter, are constructed, and the quantitative relations among scale parameter, shape parameter and four characteristic quantities are established by using BP neural network. The determination coefficients are 0.992 and 0.994, respectively. On this basis, the measured data and the trained BP neural network are used to solve the scale and shape parameters, and an amplitude distribution model of sea clutter is established, which is compared with empirical formula and mixed estimation method. The signal power of sea clutter is determined by analyzing the back-scattering coefficient under different sea conditions, so as to provide a sea clutter model for evaluating the imaging performance of missile-borne SAR under different sea conditions. Key

An Improved Serial Peak Cancellation Method for PAPR Suppression in OFDM System

ZHANG Shichao, CHEN Chong, REN Shuai, WEN Bin, WEI Peng

2020, 41(3): 526-533. doi:10.3969/j.issn.1000-1093.2020.03.013

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An improved serial PAPR suppression method is proposed for the high peak-to-average power ratio（PAPR） of orthogonal frequency division multiplexing（OFDM）system. The proposed method is used to find the peak point exceeding the threshold via the rising edge and falling edge of signal amplitude. In the proposed method, a weighted window is used to effectively suppress the high peak in a serial processing mode. Simulated results show that, compared to the existing methods, the improved method is capable of effectively suppressing the PAPR, while the number of peak cancellations is reduced by its accurate peak search, which helps to reduce the implementation complexity and enhance the bit error rate (BER) performance. Key

Experimental Investigation into the Cavity Shape and Pressure Characteristics of Supercavitating Vehicle with Elastic Trailing Edge

HOU Dongbo， WANG Cong， XIA Weixue， LI Yiguo， ZHAO Jing

2020, 41(3): 534-541. doi:10.3969/j.issn.1000-1093.2020.03.014

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A vehicle model with variable stiffness elastic trailing edge is designed to analyze the influence of elastic trailing edge on the hydrodynamic characteristics of supercavitating vehicles. The cavity shape and the pressure characteristics at different differential pressures and ventilation rates are studied through water tunnel experiment. In the experiment, an industrial camera is used to observe the shape of elastic trailing edge and the flow field, and a dynamic measurement system is used to measure the pressure fluctuation about the feature points. The influence of elastic trailing edge on the hydrodynamic characteristics of supercavitating vehicle is analyzed by comparing the changes of cavity shape and pressure fluctuation. The results show that the deformation of elastic trailing edge increases with the increase in the differential pressure coefficient. When the diameter ratio of the elastic trailing edge to the main body of vehicle is 1.35, the elastic trailing edge has an obvious effect on the cavity shape, and the cavity is closed in front of the trailing edge. Behind the trailing edge, the surface pressure of the model increases with the surface contacting water. With the continuing increase in diameter ratio, a tail cavity appears and fluctuates wildly, which causes the reduction in the wetted area downstream the elastic trailing edge and the drop in surface pressure. Key

Least Squares Estimation Performance for TDOA Target Localization in Underwater Acoustic Sensor Networks

WANG Ling, SHEN Xiaohong, KANG Yuzhu, HUA Fei, WANG Haiyan

2020, 41(3): 542-551. doi:10.3969/j.issn.1000-1093.2020.03.015

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A weighted total least squares method based on double error model is proposed for the target localization in the simultaneous presence of measurement error and sensor node position error in underwater acoustic sensor networks. A TDOA target localization model with double errors is established. The weighted total least squares method is used to solve the proposed model, and the expression of the weights is derived. The proposed algorithm model is to use the prior information of measurement error variance and sensor node position error variance to obtain the final target position estimate by iteration method. The simulation and water tank experimental verification of the proposed method were made by simulating the simultaneous existence of the measurement error and the sensor node positions error. The results show that the proposed target localization method based on weighted total least squares has higher localization performance. Key

Research on the 3D Sonar Single-frame Reconstruction Based on Local Outlier Factor Algorithm

ZENG Teng, ZHANG Chunhua, WANG Peng

2020, 41(3): 552-558. doi:10.3969/j.issn.1000-1093.2020.03.016

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3D sonar always acquires the data point with outliers in the complex marine environment, which affects the post processing and visualization of point cloud. 3D beamforming imaging, maximum filtering and coordinate transformation are made for the sonar data to obtain the original point cloud. The local outlier factor (LOF) algorithm is used to eliminate the abnormal points, and a modified triangulation growing method is used for single-frame reconstruction. In the modified triangulation growing method, the crucial process of ‘the third point’ finding in triangular mesh generation is simplified. A denoising method based on LOF algorithm can be used to eliminate the points not belonging to the target under the premise in keeping the real contour of target compared with the traditional threshold denoising method. And the 3D reconstruction result of more realistic target contour can be achieved from the sonar data obtained by the proposed denoising method. Key

Research on Target Tracking Method Based on Ship Electric Field

ZHANG Jiawei, YU Peng， JIANG Runxiang, SUN Baoquan

2020, 41(3): 559-566. doi:10.3969/j.issn.1000-1093.2020.03.017

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For the contradiction between the model accuracy and the tracking model dimension in the ship electric field tracking, the influences of point charge number and the depth of observation point on the accuracy of model are analyzed and the minimum requirement for point charge number on the corresponding depth plane is defined based on the ship electric field point charge array model and the ship electric field inversion algorithm. In the analysis, the dimension of tracking filter is reduced while ensuring the modeling accuracy and the stability of filtering algorithm.A progressive update extended Kalman filter (PUEKF) was designed for the simulation analysis and experimental verification of ship electric field tracking. The results show that a electric field model with a small number of point charges can be used to replace the complex ship electric field point charge array model in ship electric field tracking, which has high tracking accuracy. The PUEKF can effectively improve the initial error tolerance range and has high filtering stability. The tracking error is less than 10m in the range of 500 m. The PUEKF has low computational cost, which is suitable for engineering applications for the ship electric field tracking. Key

Influence of Environmental Factors on Corrosive Electrostatic Field under Laminar Current

LIU Dehong, ZHANG Jianchun, WANG Xiangjun

2020, 41(3): 567-576. doi:10.3969/j.issn.1000-1093.2020.03.018

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In order to fit the corrosive electrostatic field produced by the theoretical model better with the experimental results measured in the actual seawater environment, a method for calculating point charge potential based on Sommerfeld integral in flowing media is proposed, and the influence of environmental factors on the amplitude of electrostatic field is qualitatively analyzed. The corrosion current density under the control of electrochemical polarization and concentration polarization is calculated based on the electrochemical and hydrodynamic theories, a point charge model is established based on the corrosion current density, and the corrosive electrostatic field in a medium is calculated. The variation rule of electrostatic field amplitude with the medium temperature, salinity and flow rate was obtained and verified by experiments. The results show that the actual corrosion situation is more complex than that of the theoretical model. Under certain environmental conditions, the experimental results are good agreement with the theoretically calculated results, and the average fitting error is less than 10%. Key

Non-turntable Field-calibration Method for Gyroscope Based on Optimal Analysis

YANG Guanjinzi， LI Jianchen， HUANG Hai， GUO Linna

2020, 41(3): 577-584. doi:10.3969/j.issn.1000-1093.2020.03.019

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Gyro is served as an important inertial device for vehicle attitude measurement. The error drift of gyroscope is due to long transportation and storage，which leads to the reduction in the measurement accuracy of motion parameters， thus needing to calibrate the gyroscope before use. A non-turntable field-calibration method for medium accuracy gyroscope based on optimal analysis is proposed in accordance with the working conditions without high precision turntable equipment in the field and the requirement of the indexes of medium accuracy gyroscope. The calibration problem is transformed into an optimal analytical problem by establishing the mapping relationship between the gyro output and the earth rotation rate as well as the accelerometer output. The method， combined with the improved genetic algorithm， is used to achieve the goal of simplifying the operation steps， doing not rely on turntable and other auxiliary equipment， shortening the calibration time and improving the calibration accuracy. The validity of the method is verified by mathematical and hardware-in-the-loop simulation experiments. The results show that the method can be used effectively to achieve the accuracy of medium-accuracy gyroscope calibration. Key

Path Planning and Tracking Control of Autonomous Vehicle for Obstacle Avoidance

DENG Haipeng， MA Bin， ZHAO Haiguang， L Liang, LIU Yu

2020, 41(3): 585-594. doi:10.3969/j.issn.1000-1093.2020.03.020

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Emergency obstacle avoidance is one of the key points for autonomous driving system. A path planning controller based on non-linear model predictive control and a path tracking controller based on linear time-varying model predictive control are designed.In path planning controller，an obstacle-avoiding function is used to adjust the distance between the intelligent vehicle and obstacles by calculating the value of obstacle-avoiding function.A new route is supposed to be planned，which can not only keep away from obstacles but also decrease the deviations from the global course，by considering the different weights of obstacle-avoiding function and the planning error. In path tracking controller，the solution of linear time-varying model predictive control is converted into a positive-definite quadratic program.And then the desired steering angles of front wheel are calculated by using the reference trajectory and orientation angle of vehicle center. The results show that the obstacle-avoiding controller has strong robustness and the path tracking controller has better performance in controlling accuracy and vehicle dynamics stability when a vehicle travels at 60 km/h，80 km/h，or 100 km/h. The maximal side-slip angle is no more than 1°，and the maximal deviation of yaw angle is less than 2.5°.Obstacle avoiding action occurs in advance with the increase in velocity of autonomous vehicle. In addition，the dual-MPC controller is adaptive to the circumstance of multi-obstacles avoidance as well，which can be easily demonstrated by the small deviation of yaw angles and small side-slip angles.Key

Research on Intelligent Inspection and Acceptance Method of Equipment Based on Ontology Technology

LI Zexi, MENG Chen, WANG Cheng

2020, 41(3): 595-607. doi:10.3969/j.issn.1000-1093.2020.03.021

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An ontology technology-based intelligent inspection and acceptance method of equipment is proposed to improve the problems of current equipment inspection and acceptance, such as heavy and high repetitive workload, and dependence of acceptance effect on the experience and subjective judgment of the inspectors. The key implementation techniques for the proposed method are described in detail, including establishment of ontology library for equipment inspection and acceptance, design of rule database of equipment inspection and acceptance, and intelligent judgment of inspection findings based on ontology knowledge reasoning, etc. The simulation experiments were made on the ontoloty development tool Protégé platform by taking part of the inspection and acceptance information of the shell products as an example. The experimental results show that the proposed method can be used to improve the accuracy and efficiency of equipment inspection and acceptance.

Active Defense Strategy Selection of Military Information Network Based on Incomplete Information Game

WANG Zengguang， LU Yu, LI Xi

2020, 41(3): 608-617. doi:10.3969/j.issn.1000-1093.2020.03.022

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The characteristics of attack-defense confrontation behavior of military information network are analyzed for its defense strategy of military information network, and a method for selecting an active defense strategy is proposed. A network attack-defense game model is constructed based on incomplete information game. And the attack-defense payoffs are quantified from the perspective of network security attributes. An active defense strategy selection algorithm is proposed by taking the defense effectiveness as the criterion of strategy selection. Compared with the classical network defense method based on game theory, the proposed method is more suitale for network attack and defense practice in model design and payoff quantification. At the same time, the active defence strategy can be selected in the form of pure strategy, which is easier to understand and operate than the current optimal strategy selection in the form of probability. The rationality and feasibility of the proposed method are verified through a representative experiment, and the general rules of network defense are summarized through the analysis of defense payoffs.Key

Numerical Simulation of Dust Concentration Distribution in Confined Space

XU Chenyoushi， ZHANG He， ZHA Bingting， ZHENG Zhen， CHEN Jingyi

2020, 41(3): 618-624. doi:10.3969/j.issn.1000-1093.2020.03.023

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A dust laboratory design scheme is presented for the research on the anti-dust interference ability of laser fuze. An adjustable dust test plane with uniform concentration is formed under laboratory conditions, and then the anti-dust interference ability of laser fuze is quantitatively analyzed. The k-ε turbulent mathematical model and the discrete phase model (DPM) is established, and the dust laboratory is numerically simulated by computatinal fluid dynamcs FLUENT software based on the semi-implicit method of pressure linked equations （SIMPLE） with hybrid difference scheme and co-located grid. The distributions of dust concentration in different cross sections of the computing domain and the trend of concentration over time can be obtained through simulation. The results indicate that the uniform concentration of dust is affected by the wind velocity of the wind inlet and the mass flow rate of the feed inlet, and the uniform concentration grows linearly with the wind velocity while decays exponentially with the flow rate. And the natural wind can speed up the sedimentation speed of dust. Key

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