OPTIMIZATION OF WEIGHTED HIGH-RESOLUTION RANGE PROFILE FOR RADAR TARGET RECOGNITION

For the recognition of high-resolution range profile （HRRP） in radar, the weighted HRRP can reduce the instability of range cells caused by the attitude change of targets. A novel approach is proposed to optimize the weighted HRRP. In the approach, the separability of weighted HRRPs in different targets is measured by de- signing an objective function, and the weighted coefficients are computed by using the gradient descent method, thus enhancing the influence of stable range cells. Simulation results based on five aircraft models show that the approach can effectively optimize the weighted HRRP and improve the recognition accuracy.

Accuracy of forecast of mine tremors location

The Upper Silesian Coal Basin is one of the most active mining areas in the world in respect of seismicity. Underground mining in this area takes place in a special environment with a high degree of risk of unpredictable event occurrence. Especially dangerous are phenomena that occur during the extraction of deposits at great depths in the environment of compact rocks. Deep underground mining violates the balance of these rocks and induces dynamic phenomena at the longwall life （in terms of distance） referred to as mine tremors. The sources of these tremors are located in layers characterised by high strength, especially in thick sandstone strata occurring in the roof of the mined seam. In the paper a discussion is presented about the influence of mining intensity （longwall face speed） on the location of mine tremor sources, both in the direction of longwall life （in terms of distance） and towards the surface. The presented material has been prepared basing on the results of tests and measurements carded out at the Central Mining Institute.

考虑既有船坞的深基坑工程设计

本工程地处城市中心区复杂环境,既有船坞位于基坑范围内,这种情况的审计工程尚属国内先例。本文针对既有船坞对基坑工程的影响,介绍了基坑支护设计,如既有船坞主体结构及下部桩基障碍物清除、围护墙在既有船坞结构与工程桩重叠时的实施、船坞底板下工程桩拔出及承压水层突涌风险控制、船坞底板下桩基遭遇实际桩位同图纸偏差时的风险控制、既有船坞结构与支护结构衔接等。实践表明,相应的设计技术有效地保证了工程工期、基坑安全及周边环境的安全。

A method for computing unsupported roof distance in roadway advancement and its in-situ application

A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.

On the first eigenvalue of Finsler manifolds with nonnegative weighted Ricci curvature

We prove that for a compact Finsler manifold M with nonnegative weighted Ricci curvature,if its first closed(resp.Neumann)eigenvalue of Finsler-Laplacian attains the sharp lower bound,then M is isometric to a circle(resp.a segment).Moreover,a lower bound of the first eigenvalue of Finsler-Laplacian with Dirichlet boundary condition is also estimated.These generalize the corresponding results in recent literature.

Lower bounds on the minimum distance in Hermitian one-point differential codes

Korchmaros and Nagy [Hermitian codes from higher degree places. J Pure Appl Algebra, doi： 10. 1016/j.jpaa.2013.04.002, 2013] computed the Weierstrass gap sequence G（P） of the Hermitian function field Fq2 （H） at any place P of degree 3, and obtained an explicit formula of the Matthews-Michel lower bound on the minimum distance in the associated differential Hermitian code CΩ（D, mP） where the divisor D is, as usual, the sum of all but one 1-degree Fq2-rational places of Fq2 （H） and m is a positive integer. For plenty of values of m depending on q, this provided improvements on the designed minimum distance of CΩ（D, mP）. Further improvements from G（P） were obtained by Korchmaros and Nagy relying on algebraic geometry. Here slightly weaker improvements are obtained from G（P） with the usual function-field method depending on linear series, Riemann-Roch theorem and Weierstrass semigroups. We also survey the known results on this subject.

SARG04 decoy-state quantum key distribution based on an unstable source

A three-state protocol for the SARG04 decoy-state quantum key distribution(QKD)based on an unstable source is presented. The lower bound to the secure key generation rate is derived without using the basic hypothesis of the original decoy-state idea.The three-state SARG04 decoy-state protocol with an unstable parametric down-conversion source is considered in the simulation.The simulation results show that the protocol in this paper with an unstable source gives a key generation rate that is close to that with a stable source,and only slight advantage appears by using a stable source when the transmission distance is long.So the SARG04 decoy-state protocol with an unstable source still can obtain the unconditional security with a slightly shortened final key.