Reciprocity Relation between Alternative Gravity Formulas

We compare Newton’s force law of universal gravitation with a corrected simple approach based on Bhandari’s recently presented work, where the gravitation constant G is maintained. A reciprocity relation exists between both alternative gravity formulas with respect to the distances between mass centers. We conclude a one-to-one mapping of the two gravitational formulas. We don’t need Einstein’s construct of spacetime bending by matter.

Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values.A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution,changing the relative distance measurement method,and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit.Through the construction of absolute ideal solution,improvement of relative distance measurement method and introduction of entropy weight,the inherent defects of TOPSIS decision analysis method,such as non-absolute order,reverse order and unreasonable weight setting,can be overcome.Simple in calculation and easy to understand,the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database.Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration,low wear rate,and good compatibility with the drilled formations in actual drilling.This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency,long life and good economics in oilfields.

A Cooperative Localization Method for Leader–Follower Multiple UAVs Using Continuous Relative Ranging Information

Cooperative localization(CL)utilizing multiple unmanned aerial vehides(UAVs)has become the current development trend and research hotspot.The tnditional distance-based CL method.typically uses principle of the spherical intersection to achieve UAV high-precision positioning.However,this distance based CL strategy requires several leader UAVs at the known positions.Thus,a cooperative localization method for leader-follower multiple UA Vs using continuous relative ranging information is proposed in this paper.Aiming at the UAV formation consists of a leader UAV node with the known position and at least a follower UAV that needs to be located.Using the Inertial short-time high-precision relative position constraint and the con-tinuous relative distance constraints with the leader UAV nodes,the closed-form solution of follower UAV's three-dimensional position can be obtained using spherical intersection prin-ciple.On this basis,we derive and construct follower UAV's position observation equation.The:developed strategy requires a single known position leader UAV node to realize high-precision CL,which can efctively solve the taditional distance-based collaborative location problem in case the number of leader UAVs is small.The simulation and experimental results demonstrate that the proposed method significantly improves follower UAV's positioning accuracy,and neglects the limitation of the traditional distance-based CL method on the number of leader UAV nodes at known positions.

Deep learning method for testing the cosmic distance duality relation

The cosmic distance duality relation(DDR)is constrained by a combination of type-Ⅰa supernovae(SNe la)and strong gravitational lensing(SGL)systems using the deep learning method.To make use of the full SGL data,we reconstruct the luminosity distance from SNeⅠa up to the highest redshift of SGL using deep learning,and then,this luminosity distance is compared with the angular diameter distance obtained from SGL.Considering the influence of the lens mass profile,we constrain the possible violation of the DDR in three lens mass models.The results show that.in the singular isothermal sphere and extended power-law models,the DDR is violated at a high confidence level,with the violation parameterη0=-0.193-0.019+0.021andη0=-0.247-0.013+0.014,respectively.In the power-law model,however,the DDR is verified within a 1σconfidence level,with the violation parameterη0=-0.014-0.045+0.053.Our results demonstrate that the constraints on the DDR strongly depend on the lens mass models.Given a specific lens mass model,the DDR can be constrained at a precision of O(10-2)using deep learning.