High-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer based on probability density evolution method

This paper proposed an efficient research method for high-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer.Firstly,the dynamic model of projectile motion is established considering the flexible deformation of the barrel and the interaction between the projectile and the barrel.Subsequently,the accuracy of the dynamic model is verified based on the external ballistic projectile attitude test platform.Furthermore,the probability density evolution method(PDEM)is developed to high-dimensional uncertainty quantification of projectile motion.The engineering example highlights the results of the proposed method are consistent with the results obtained by the Monte Carlo Simulation(MCS).Finally,the influence of parameter uncertainty on the projectile disturbance at muzzle under different working conditions is analyzed.The results show that the disturbance of the pitch angular,pitch angular velocity and pitch angular of velocity decreases with the increase of launching angle,and the random parameter ranges of both the projectile and coupling model have similar influence on the disturbance of projectile angular motion at muzzle.

Optimization of projectile aerodynamic parameters based on hybrid genetic algorithm

Aerodynamic parameters are important factors that affect projectile flight movement. To obtain accurate aerodynamic parameters, a hybrid genetic algorithm is proposed to identify and optimize the aerodynamic parameters of projectile. By combining the traditional simulated annealing method that is easy to fall into local optimum solution but hard to get global parameters with the genetic algorithm that has good global optimization ability but slow local optimization ability, the hybrid genetic algo- rithm makes full use of the advantages of the two algorithms for the optimization of projectile aerodynamic parameters. The simulation results show that the hybrid genetic algorithm is better than a single algorithm.

Catalogs of ground motion parameters for earthquake-prone regions in Kazakhstan

The catalogs of ground motion parameters for earthquake-prone regions of Kazakhstan used for modeling seismic effects in seismic hazard assessment and microzonation are presented.

Average Speed in Projectile Motion and in General Motion of a Particle

We calculate the average speed of a projectile in the absence of air resistance, a quantity that is missing from the treatment of the problem in the literature. We then show that this quantity is equal to the time-average instantaneous speed of the projectile, but different from its space-average instantaneous speed. It is then shown that this behavior is shared by general motion of all particles regardless of the dimensionality of motion and the nature of the forces involved. The equality of average speed and time-average instantaneous speed can be useful in situations where the calculation of one is more difficult than the other. Thus, making it more efficient to calculate one by calculating the other.

A new calibration algorithms of spinning projectile aerodynamic parameters

This paper demonstrates that the application of calibration algorithms of aerodynamic parameters for the trajectory of spinning projectile is successful. First, from the point of view of the trajectory simulation, a general summary of well-known trajectory models is given. A five degrees of freedom （5 DOF） model is developed that can match the projectile motion essentially in the vertex region, and the results obtained by 5 DOF model are in close agreement with those of a more sophisticated 6 DOF model for elevation angles above 45 degrees. Secondly, the calibration algorithms have been developed and are summarized. The methods of calibrating the flight trajectory models are compared, and these methods are shown to be effective in the representative cases. In addition, the method of Math number calibration （MNC） is presented; some possible areas in MNC for further investigation are indicated together with benefits to be gained. The utilization of MNC schemes not only allow a worthwhile reduction of calibration rounds firing in range and accuracy （R＆A） trial and production of firing tables （PFT） test, but also make PFT and fire control data （FCD） more cost effective.

Three-dimensional motion parameters estimation from stereo image sequences based on infrared reflective markers

In this paper,an innovative 3D motion parameters estimation method from stereo image sequences based on infrared(IR) reflective markers is presented.It was assumed that two high speed CCD cameras had been calibrated previously.The method consists of the following steps:1) the coordinate of several markers and depth map for each stereo pair was determined from the sequences of stereo images by relations of markers' coordinate the correspondence between markers was established,2) the 3D motion parameters of the target was computed based upon the matched markers' coordinate,and 3) translated 3D motion parameters estimation into the problem of least square according to the movement model of the object to be measured.Without using line,curve or corner correspondence,this method can calculate the depth of these markers feature easily and quickly in contrast to traditional approaches.The two CCD cameras work on 200 f/s,and each processing cost time is about 3 ms.It was found that,by using several markers and a large number of stereo images,this method can improve the computational speed,robustness and numerical accuracy of the motion parameters in comparison with traditional methods.The virtual simulation experiment was conducted using synthesized stereo image sequences based on 6-DOF motion platform and the experimental results proved the validity of our approach and showed that the translation and rotation precision is up to 0.1 mm and 0.1°.

Optimal design of the aerodynamic parameters for a supersonic two-dimensional guided artillery projectile

An optimization method is introduced to design the aerodynamic parameters of a dual-spin twodimensional guided projectile with the canards for trajectory correction. The nose guidance component contains two pairs of canards which can provide lift and despin with the projectile for stability. The optimal design algorithm is developed to decide the profiles both of the steering and spinning canards,and their deflection angles are also simulated to meet the needs of trajectory correction capabilities.Finally, the aerodynamic efficiency of the specific canards is discussed according to the CFD simulations.Results that obtained here can be further applied to the exterior ballistics design.

3D Motion Parameters Determination Based on Binocular Sequence Images

Exactly capturing three dimensional (3D) motion i nf ormation of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision s ystem and a method for determining 3D motion parameters of an object from binocu lar sequence images are introduced. The main steps include camera calibration, t he matching of motion and stereo images, 3D feature point correspondences and re solving the motion parameters. Finally, the experimental results of acquiring th e motion parameters of the objects with uniform velocity and acceleration in the straight line based on the real binocular sequence images by the mentioned meth od are presented.

Influence of gas pressure state on the motion parameters of coal-gas flow in the outburst hole

Carried on the one-dimensional analysis to the motion state of coal-gas flow in the outburst hole, and deduced the relational expression between the motion parameters （containing of velocity, flow rate and density etc.） of bursting coal-gas flow and gas pressure in the hole, then pointed out the critical state change of coal-gas flow under different pressure conditions which had the very tremendous influence on both stability and destructiveness of the entire coal and gas outburst system. The mathematical processing and results of one-dimensional flow under the perfect condition are simple and explicit in this paper, which has the certain practical significance.

An investigation on the ground motion parameters and seismic response of underground structures

Peak ground acceleration (PGA), frequency content and time duration are three fundamental parameters of seismic loading. This study focuses on the seismic load frequency and its effect on the underground structures. Eight accelerograms regarding different occurred earthquakes that are scaled to an identical PGA and variation of ground motion parameters with ratio of peak ground velocity (PGV) to PGA, as a parameter related to the load frequency, are considered. Then, concrete lining response of a circular tunnel under various seismic conditions is evaluated analytically. In the next, seismic response of underground structure is assessed numerically using two different time histories. Finally, effects of incident load frequency and frequency ratio on the dynamic damping of geotechnical materials are discussed. Result of analyses show that specific energy of seismic loading with identical PGA is related to the seismic load frequency. Furthermore, incident load frequency and natural frequency of a system have influence on the wave attenuation and dynamic damping of the system.

A Robust Algorithm for Estimating Motion Parameters Based on the Modified LMedS

We put forward a robust method for estimating motion parameters from the 3-D space position vectors of feature points on the basis of the modified least median of squares (LMedS) regression estimator. First, initial values of motion parameters are estimated by the primary LMedS, then the motion parameters with an iterative reweighted estimator are re-estimated, in which a hybrid weight function of Huber weight and Tukey weight takes place of the dichotomy weight in the primary LMedS, The algorithm alleviates the difficulty of deleting some outliers while SNR is too low, so we can get a more accurate estimation. Computer simulations show that its performance is satisfactory.

Ground motion parameters of Shillong plateau: One of the most seismically active zones of northeastern India

Strong ground motion parameters for Shillong plateau of northeastern India are examined. Empirical relations are obtained for main parameters of ground motions as a function of earthquake magnitude, fault type, source depth, velocity characterization of medium and distance. Correlation between ground motion parameters and characteristics of seismogenic zones are established. A new attenuation relation for peak ground acceleration is developed, which predicts higher expected PGA in the region. Parameters of strong motions, particularly the predominant periods and duration of vibrations, depend on the morphology of the studied area. The study measures low estimates of logarithmic width in Shillong plateau. The attenuation relation estimated for pulse width critically indicates increased pulse width dependence on the logarithmic distance which accounts for geometrical spreading and anelastic attenuation.

COORDINATION OF THE MOTION PARAMETERS WITHIN STEP-BY-STEP INTEGRATION FOR DYNAMIC EQUATION

A method is presented that coordinates the calculation of the displacement, velocity and acceleration of structures within the time-steps of different types of step-by-step integration. The dynamic equation is solved using an energy equation and the calculating data of the original method. The method presented is better than the original method in terms of calculating postulations and is in better conformity with the system's movement. Take the Wilson-θ method as an example. By using the coordination process, the calculation precision has been greatly im proved (reducing the errors by approximately 90% ), and the greater part of overshooting of the calculation result has been eliminated. The study suggests that the mal-coordination of the motion parameters within the time-step is the major factor that contributes to the result errors of step-by-step integration for the dynamic equation.

The Relationship Among Bedrock Seismic Ground Motion Parameters with Different Exceedance Probabilities in the Panxi Area

Based on the calculation of the bedrock effective peak acceleration (EPA) zoning map in the Panxi area, the ratios of EPA with exceedance probabilities of 63%, 5%, 3%, 2% and 1% over 50 years to that of 10% in 50 years are 0.302, 1.30, 1.55, 1.76 and 2.14, respectively. The seismic effect will be conservative and safe if taking this zoning map as the earthquake resistant fortification level and following the relevant rules of the Code for Seismic Design of Buildings (GBJ11 89) to calculate the seismic effect. Furthermore, the main factors that influence the A10/A63 ratios have been found to be the attenuation relationship of seismic ground motion, the division of seismic potential source regions and the seismicity parameters. These achievements are helpful to the spreading and applying of the zoning map.

Deduction of Market Prices for Futures Derivatives From Projectile Physics With Effects of the Simple Harmonic Oscillations on Equilibrium Price Positions

We investigated the motions associated with prices for futures contracts within financial markets.We aimed to derive the market prices from the physics approach.We used the projectile motion models defined under two distinct conditions(perfect/horizontal and imperfect/drag implication)based on Newton’s and Galileo’s laws of motion.In addition,we applied the simple harmonic oscillatory model to present the movements of prices from the market equilibrium position.Despite that it was more theoretical,we managed to derive the futures price functions and the results showed that futures prices depend largely on market forces of demand and supply and underlying assets price behaviour.Also,we managed to find the terminal prices for the securities given the initial prices,which are a worrying matter to the trading parties.The equilibrium price analysis was done and the simple harmonic model proved to be efficient in such modelling.We managed to identify the price motions to and from the equilibrium point with markets.Results suggested that it is the market frictions(market forces of demand and supply)that propel prices to move.Also,we noted that these forces are responsible for bringing back the prices at equilibrium if the market is left to operate as free.Nevertheless,from the performance comparison of the two models used,results suggested that futures price function from a drag variable is more powerful in modelling the price behaviour for options than the one sorely controlled by market demand and supply forces.And the simple harmonic oscillator model is good at modelling the equilibrium movements of asset prices.Above all,we used the mean absolute deviation(MAD)to validate our futures derivative pricing model.Fortunately,the obtained MAD results supported the efficiency of our model.However,it should not be carelessly taken that the projectile models used are much good at price motions/movements within the market from time to time with a stunted ability to capture in other facts of interest,such as volatility coefficients which pave a research way for other scholars.

Micro-Doppler effect testing technique for attitude of projectile in space flight

To measure projectile attitude in space flight, based on continuous wave （CW） radar, a new micro-Doppler effect testing technique is developed in this paper. It also establishes radar testing model for attitude of flying projectile and resolve micro-Doppler effect of projectile motion attitude. By distinguishing and geting attitude parameters such as micro-motion period, this technique can in- tuitively estimate the flight stability of projectile, and the validity of this technique is proved accord- ing to flight tests.

Machine learning prediction models for ground motion parameters and seismic damage assessment of buildings at a regional scale

This study examines the feasibility of using a machine learning approach for rapid damage assessment of rein-forced concrete(RC)buildings after the earthquake.Since the real-world damaged datasets are lacking,have limited access,or are imbalanced,a simulation dataset is prepared by conducting a nonlinear time history analy-sis.Different machine learning(ML)models are trained considering the structural parameters and ground motion characteristics to predict the RC building damage into five categories:null,slight,moderate,heavy,and collapse.The random forest classifier(RFC)has achieved a higher prediction accuracy on testing and real-world damaged datasets.The structural parameters can be extracted using different means such as Google Earth,Open Street Map,unmanned aerial vehicles,etc.However,recording the ground motion at a closer distance requires the installation of a dense array of sensors which requires a higher cost.For places with no earthquake recording station/device,it is difficult to have ground motion characteristics.For that different ML-based regressor models are developed utilizing past-earthquake information to predict ground motion parameters such as peak ground acceleration and peak ground velocity.The random forest regressor(RFR)achieved better results than other regression models on testing and validation datasets.Furthermore,compared with the results of similar research works,a better result is obtained using RFC and RFR on validation datasets.In the end,these models are uti-lized to predict the damage categories of RC buildings at Saitama University and Okubo Danchi,Saitama,Japan after an earthquake.This damage information is crucial for government agencies or decision-makers to respond systematically in post-disaster situations.

Evaluation of ground motion parameters and seismic response of reinforced concrete buildings from the Mw 6.9,2011 Sikkim earthquake

The continuous collision of the Eurasian plate and the Indian plate has resulted in several earthquakes in the Himalayan region.The 6.9 Mw 2011 Sikkim earthquake,which caused immense damage to the built environment in Sikkim,was triggered by an intraplate source on the overriding Eurasian plate.Strong ground motions from the earthquake were recorded at stations established by IIT Roorkee as part of the PESMOS program.In this paper,near-field and far-field ground motions from this earthquake were analyzed to evaluate their key characteristics and examine their time-frequency features by employing Fast Fourier Transforms(FFTs)and Continuous Wavelet Transforms(CWTs).A comparison between the ground motion parameters of near-field and far-field seismic waves highlights the distinct characteristics of near-field ground motions.Additionally,the impact of near-field and far-field ground motions on the seismic response of a code-compliant RC building is investigated.The results from the non-linear time history analyses indicate that the roof displacements,drift ratio and strain induced in the frame elements are less than the code-prescribed maximum limits.Further,the demand and capacity levels for the RC frame elements were evaluated to compute the performance ratios.The results indicate that the extensive damage to reinforced concrete buildings in the 2011 Sikkim quake was primarily due to the nonengineered nature of the structures and also due to the non-compliance of the built structures to the seismic design code provisions.

A novel virtual four-ocular stereo vision system based on single camera for measuring insect motion parameters

A novel virtual four-ocular stereo measurement system based on single high speed camera is proposed for measuring double beating wings of a high speed flapping insect. The principle of virtual monocular system consisting of a few planar mirrors and a single high speed camera is introduced. The stereo vision measurement principle based on optic triangulation is explained. The wing kinematics parameters are measured. Results show that this virtual stereo system not only decreases system cost extremely but also is effective to insect motion measurement.

NOISE-INDUCED CHAOTIC MOTIONS IN HAMILTONIAN SYSTEMS WITH SLOW-VARYING PARAMETERS

This paper studies chaotic motions in quasi-integrable Hamiltonian systems with slow-varying parameters under both harmonic and noise excitations. Based on the dynamic theory and some assumptions of excited noises, an extended form of the stochastic Melnikov method is presented. Using this extended method, the homoclinic bifurcations and chaotic behavior of a nonlinear Hamiltonian system with weak feed-back control under both harmonic and Gaussian white noise excitations are analyzed in detail. It is shown that the addition of stochastic excitations can make the parameter threshold value for the occurrence of chaotic motions vary in a wider region. Therefore, chaotic motions may arise easily in the system. By the Monte-Carlo method, the numerical results for the time-history and the maximum Lyapunov exponents of an example system are finally given to illustrate that the presented method is effective.