一种用于多径衰落水声信道的盲均衡算法仿真研究

在水声数字通信中，严重的多径衰落和多普勒频移是影响通信性能的两个主要因素。研究了一种分数间隔判决反馈盲均衡结构，以有效地克服水声信道多径衰落的不利影响。同时，针对水声信道的时变多普勒特性，在分数间隔判决反馈结构的基础上，提出了一种修正常数模分数间隔判决反馈盲均衡与二阶数字锁相环相结合的盲均衡算法，以纠正信道引入的载波相位旋转。最后通过计算机仿真，将该算法与常数模波特间隔判决反馈盲均衡算法进行了性能对比，仿真结果证明了该算法的有效性。因此，该算法具有良好的实用性和应用前景。     

应变式传感器恒压源间歇供电

分析了恒压源供电下的桥路输出特性以及影响电桥电压灵敏度的各种因素.供电电压的增加会受到桥臂允许功耗的限制,从而制约了电桥电压灵敏度的提高,并产生电阻"温升"和热噪声.针对电桥存在的上述问题提出的恒压源间歇供电方式,不仅可以提高传感器的灵敏度,还有效地降低了应变片电阻的"温升"和热噪声,提高了传感器的精度.     

The Application of Similarity Theory in Designing Large Deflection Buckling Spring-Piece

Large Deflection Buckling Spring-Piece (LDBSP) refers to the deformation of an end-fixed flat spring-piece under normal loadings. Plastic deformation usually appears in LDBSP.The static characteristic curve is very particular, because within its linear deflection region, the spring constant can be designed to be any value from minus to plus. With its obvious advantages of large liner deflection range, low spring constant, etc., the LDBSP has now been extensively applied to the exciting device, low-frequency shock absorbers and so on. The static characteristic curve of LDBSP belongs to the nonlinear problem of an arch with varying section. Therefore, it is difficult to obtain it theoretically. The formulae for designing LDBSP have not been set up yet. In this study,the authors apply similarity theory to analyze the liner deflection range A and the spring constant K, and derive the relationship of similarity criterion, finally obtain a set of formulae for designing LDBSP by model test and the least square method, which can be applied in engineering design.Through the research, it is proved that it is unnecessary to keep geometrical similarity of spring-piece shape. This fact extends the application scope of the formulae. The proposed formulae for designing LDBSP thereby can be applied for any dimensions within the range allowed.     

具有齐次核的Hilbert型积分不等式的构造特征及应用

利用实分析技巧,研究具有齐次核的Hilbert型积分不等式的构造特征及取最佳常数因子的充要条件,得到了最佳常数因子的解析表达式.     

有界复形的 Modi ed Ringel Hall 代数的结构常数

设k是有限域.A是k上的满足一定有限性条件的本质小的遗传阿贝尔范畴.本文研究了有界复形范畴的modified Ringel—Hall 代数MH(A)中零微分复形乘积的结构常数，给出了它们与A的Ringel-Hall 代数H(A)的Hall数之间的关系.     

Fantastic Beasts and where (not) to find them: Local gravitational energy and energy conservation in general relativity

This paper critically examines energy-momentum conservation and local (differential) notions of gravitational energy in General Relativity (GR). On the one hand, I argue that energy-momentum of matter is indeed locally (differentially) conserved: Physical matter energy-momentum 4-currents possess no genuine sinks/sources. On the other hand, global (integral) energy-momentum conservation is contingent on spacetime symmetries. Local gravitational energy-momentum is found to be a supererogatory notion. Various explicit proposals for local gravitational energy-momentum are investigated and found wanting. Besides pseudotensors, the proposals considered include those of Lorentz and Levi-Civita, Pitts and Baker. It is concluded that the ontological commitment we ought to have towards gravitational energy in GR mimics the natural anti-realism/eliminativism towards apparent forces in Newtonian Mechanics.     

一个较精确加强型的半离散Hilbert型不等式

应用权函数的方法及Hermite Hadamard不等式, 建立一个较精确且加强型的半离散非齐次核Hilbert型不等式, 并给出该不等式具有最佳常数因子联系参数的一组等价性质及一些特殊参数不等式.      

常微分方程线性系统的一般理论与方程求解

在常微分方程的全部内容中,线性系统部分占有特别重要的地位,这不仅因为其自身的理论已被研究得十分清楚外,同时线性系统又是讨论非线性系统的基础.利用线性空间理论进一步对常微分方程线性内容及方程求解做一些分析和探究.     

赋值Banach代数的锥度量空间中的一类新型不动点定理

定义了一种向量版本的α-可容许函数,在不考虑锥的正规性的条件下,给出了赋值Banach代数的锥度量空间中的带有α-可容许函数条件的几类压缩型映射的不动点定理,所得结果大大地改进了前人的一些结果,并且举例验证了所得到的结论.      

Optimum design of equivalent accelerated life testing plans based on proportional hazards-proportional odds model

The optimum design of equivalent accelerated life testing plan based on proportional hazards-proportional odds model using D-optimality is presented.The defined equivalent test plan is the test plan that has the same value of the determinant of Fisher information matrix.The equivalent test plan of step stress accelerated life testing(SSALT) to a baseline optimum constant stress accelerated life testing(CSALT) plan is obtained by adjusting the censoring time of SSALT and solving the optimization problem for each case to achieve the same value of the determinant of Fisher information matrix as in the baseline optimum CSALT plan.Numerical examples are given finally which demonstrate the equivalent SSALT plan to the baseline optimum CSALT plan reduces almost half of the test time while achieving approximately the same estimation errors of model parameters.