无线电骚扰的统计测量方法研究

提出了一种估测数字通信系统误码率的新方法——概率信噪比评估法,该方法基于无线电噪声和电磁骚扰的统计测量。无线电噪声和电磁骚扰的统计测量方法是当前国际上研究的热点问题,通过统计测量结果可以评估噪声环境对数字通信系统的影响。给出了无线电噪声和电磁干扰统计测量所依据的理论基础和实验测试结果,建立了干扰的幅度概率分布(APD)统计模型。通过实验数据说明了干扰的统计测量特性与数字通信系统性能之间的关系。

无线电骚扰统计参量的检测及应用

介绍了无线电骚扰统计参量的检测所依据的理论基础和检测方法,通过实验说明了无线电骚扰的统计参量与数字通信系统性能之间的关系,并以此说明了无线电骚扰统计测量的意义与作用,为今后无线电骚扰和噪声的检测工作提出了有益的建议。

A simple method to extract glacier length based on Digital Elevation Model and glacier boundaries for simple basin type glacier

Glacier length is a key morphological element that has many glaciological applications; however, it is often difficult to determine, especially for glaciers that cover larger spatial areas or those that exhibit frequent temporal change. In this paper, we describe a new Arc GIS-based method that can derive glacier flow lines for determining glacier length based on digital elevation model and glacier outlines. This method involves(1) extraction of the highest and lowest points on a glacier,(2) calculation of 10-m contour lines on the glacier from 10 m to 100 m height, and(3) connection of the midpoints of each contour line with the highest and the lowest points in order to create a flow line, which is subsequently smoothed. In order to assess the reliability of this method, we tested the algorithm's results against flow lines calculated using field measurements, analysing data from the Chinese Glacier Inventory, and manual interpretation. These data showed that the new automated method is effective in deriving glacier flow lines when contour lines are relatively large; in particular, when they are between 70 m and 100 m. Nonetheless, a key limitation of the algorithm is the requirement to automatically delete repeated and closed curves in the pre-treatment processes. In addition to calculating glacier flow lines for derivation of glacier length, this method also can be used to effectively determine glacier terminus change.

Throughput-efficient wireless system and blind detection via improved particle filtering

This paper introduces throughput-efficient wireless system based on an extension to binary phasemodulations,named extended binary phase shift keying(EBPSK),and the corresponding analysis ofpower spectra,especially the extension to channel capacity are given.Importantly,a novel sequential es-timation and detection approach for this EBPSK system is proposed.The basic idea is to design a proba-bilistic approximation method for the computation of the maximum a posterior distribution via particle fil-tering method(PF).Subsequently,a new important function in PF is presented,so that the performanceof the detector has a great improvement.Finally,computer simulation illustrates that EBPSK system hasvery high transmission rate,and also the good performance of the proposed PF detector is demonstrated.

Integrated Application of Statistical Method Used in Predicting the Lanes＇ Traffic Volume of Non-detector Intersections

Based on the relationships between the lanes of signal-controlled intersections, we utilize the integration method of cluster analysis and stepwise regression and the integration method of cluster analysis and the principal component analysis method to predict the lanes＇ traffic volume of non-detector isolated controlled intersections. The results are examined by the real-time lanes＇ traffic volume data of the road network of Nanjing City. The problem of the lanes＇ traffic volume prediction of non-detector isolated signal-controlled intersections was resolved which can be widely used in urban traffic flow guidance and urban traffic control in cities.

Roll angle measurement with a large range based on the photoelectronic autocollimator

In this paper,we propose a roll angle measurement method with a large range based on the photoelectronic autocollimator.According to the corresponding relationship between the rotation position of the measured shaft and the spot position on the circular trajectory,the roll angle is calculated quickly and conveniently using a simple algorithm.Only a mirror,a coupler and a fine shaft are contained in the measurement system besides the photoelectronic autocollimator.Aiming at the terrible measurement error induced by the axis wobbly error,two measurement schemes are proposed,which are linking the fine precision shaft to the measured shaft for reducing the axis wobbly error and using the segment measurement to enlarge the radius of the circular trajectory.The experimental results show that the measurement error is decreased by ±0.38°.The roll angle error of the mechanism is ±0.14°,and the measurement precision is about ±2′.The proposed method can be widely used in the engineering fields.

Testing against second-order stochastic dominance of multiple distributions

Second-order stochastic dominance plays an important role in reliability and various branches of economics such as finance and decision-making under risk, and statistical testing for the stochastic dominance is often useful in practice. In this paper, we present a test of stochastic equality under the constraint of second-order stochastic dominance based on the theory of empirical processes. The asymptotic distribution of the test statistic is obtained, and a simple method to compute the critical value is derived. Simulation results and real data examples are presented to illustrate the proposed test method.