基于同步骨干卫星的天地一体化IP网络互联模式设计及真星试验

为解决同步骨干卫星系统无法支持空间与地面两个异构网络在网络层上直接互联互通的问题,提出基于同步骨干卫星的天地一体化IP网络互联模式。首先,阐述该天地一体化网络系统的组成和功能;接着,设计IP与CCSDS相结合的一体化互联协议体系,并以一个典型应用实例,说明协议栈的具体处理流程;最后,设计并完成基于同步骨干卫星的天地一体化IP互联试验。

刍议专业银行业务竞争

随着金融体制改革的不断深入和各种金融机构的建立,银行之间的业务交叉、竞争已成定局。从前一段的实践看,专业银行之间的业务竞争,对促进各家银行改进服务,提高经营管理水平。搞活金融和经济起到了一定的积极作用。但是,由于竞争机制不够完善,竞争中也出现了一些亟待改进的问题。本文力图从专业银行业务竞争中存在的问题、成因入手。

追星要追这样的星

一位‘时代骄子’的英雄事迹震撼了神州大地,这就是某部战士徐洪刚洒血盘肠斗歹徒的英雄壮举。‘徐洪刚热’势不可挡正升温于960万平方公里热土,成为社会各界特别是青少年崇尚的一颗璀璨之星,以至形成感人至深催人奋进的‘徐洪刚效应’。

Auto-registration and Orthorecification Algorithm for the Time Series HJ-1A/B CCD Images

How to deal with geometric distortion is an open problem when using the massive amount of satellite images at a national or global scale, especially for multi-temporal image analysis. In this paper, an algorithm is proposed to automatically rectify the geometric distortion of time-series CCD multi- spectral data of small constellation for environmental and disaster mitigation （HJ-1A/B） which was launched by China in 2008. In this algorithm, the area-based matching method was used to automatically search tie points firstly, and then the polynomial function was introduced to correct the systematic errors caused by the satellite motion along the roll, pitch and yaw direction. The improved orthorectification method was finally used to correct pixel displacement caused by off-nadir viewing of topography, which are random errors in the images and cannot be corrected by the polynomial equation. Nine scenes of level 2 HJ CCD images from one path/row were taken as the warp images to test the algorithm. The test result showed that the overall accuracy of the proposed algorithm was within 2 pixels （the average residuals were 37.8 m, and standard deviations were 19.8 m）. The accuracies of 45.96% validation points （VPs） were within 1 pixel and 90.33% VPs were within 2 pixels. The discussion showed that three main factors including the distortion patterns of HJ CCD images, pereent of cloud cover and the varying altitude of the satellite orbit may affect the search of tie points and the accuracy of results. Although the influence of varying altitude of the satellite orbits is less than the other factors, it is noted that detailed satellite altitude information should be given in the future to get a more precise result. The proposed algorithm should be an efficient tool for the geo-correction of HJ CCD multi-spectral images.

Preparation and characterization of Martian soil simulant NEU Mars-1

To develop Martian soil simulant,basalts of the Chahar volcanic group in Wulanchabu,Inner Mongolia,China were selected as the simulant initial materials,which were ground and sorted to a predetermined particle size ratio,and small amounts of magnetite and hematite were added.The main phases of NEU Mars-1 simulant were plagioclase,augite and olivine.The glass transition and crystallization temperatures of NEU Mars-1 were 547.8 and 795.7°C,respectively.The complex dielectric constant,magnetic conductivity(0.99-1.045),and dielectric loss tangent angles(0.0025-0.030)of NEU Mars-1 were all stable in the frequency range of 2-18 GHz.Mossbauer spectroscopy results showed that the mass ratio of Fe2+to Fe3+in the simulant was 77.6:22.4.The NEU Mars-1 Martian soil simulant demonstrated particle size ratio,chemical composition,phase composition,thermal stability,and dielectric property similar to Martian soil,and can be used as the substitute material to extract oxygen and metals with in-situ resource utilization technologies.

Design and simulation for large parafoil fix line object homing algorithm

Traditional parafoil homing usually uses a point as object. As the mobility of parafoil is limited by its glide ratio and wind, in some cases when the parafoil scatter area is large, or the glide ratio of parafoil is small, the deviation of its landing point to object point will be arduous to control. Accordingly, during these situations, when parafoil is used in recovery of spacecraft or satellite, the landing area of parafoil can be set as a rectangle, and the object of parafoil can be set as a line segment. The thesis of this work is designing an algorithm for parafoil homing using line segment as object. The algorithm of wind velocity and direction calculation in different flying segments was also investigated. The algorithm designed navigates the parafoil to land into the predestined area and largely reduce the probability of recovery loads falling to unwanted area to damage houses and people.

A Simple Proof of the Lower Bounds of Distortion Theorems on the Roper-Suffridge Operator

Liczberski-Starkov firstfound a lower bound for ｜｜D（f）｜｜ near the origin, where f（z）=（F（z1）,√F1（z1）z2,…,√F＇（z1）zn）＇is the Roper-Suffridge operator on the unit ball Bn in Cn and F is a normalized convex function on the unit disk. Later, Liczberski-Starkov and Hamada-Kohr proved the lower bound holds on the whole unit ball using a complex computation. Here we provide a rather short and easy proof for the lower bound. Similarly, when F is a normalized starlike function on the unit disk, a lower bound of ｜｜D（f）｜｜ is obtained again.

Capacity Analysis for Dynamic Space Networks

To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ground stations can receive per unit time. Combined with a hybrid constellation model,network capacity is calculated and further analyzed for practical cases. Simulation results show that network capacity will increase to different extents as link capacity,minimum ground elevation constraint and satellite onboard processing capability change. Considering the efficiency and reliability of communication networks,how to scientifically design satellite networks is also discussed.

新片榜

一名身携巨款的妇女在地铁站遭到四名悍匪抢劫,被铁球撞击头部而死。警察永岱和杰书奉命调查此案。两人不分昼夜地开始了调查和监视工作。为了早日抓到疯狂的凶徒,永岱和杰书利用无处不在的帮派网络收集相关信息。凶手们露出了蛛丝马迹,是四个二十岁左右的青年,全体探员立刻出击抓捕罪犯……

A comprehensive simulation of weak-light phase-locking for space-borne gravitational wave antenna

A comprehensive simulation was performed to better understand the impacts and effects of the additional technical noises on weak-light phase-locking for LISA. The result showed that the phase of the slave laser tracked well with the received transmitting light under different noise level, and the locking precision was limited by the phase readout noise when the laser frequency noise and clock jitter noise were removed. This result was then confirmed by a benchtop experimental test. The required LISA noise floor was recovered from the simulation which proved the validity of the simulation program. In order to convert the noise function into real time data with random characteristics, an algorism based on Fourier transform was also invented.

Pulsar braking:magnetodipole vs.wind

Pulsars are good clocks in the universe. One fundamental question is that why they are good clocks? This is related to the braking mechanism of pulsars. Nowadays pulsar timing is done with unprecedented accuracy. More pulsars have braking indices measured.The period derivative of intermittent pulsars and magnetars can vary by a factor of several. However, during pulsar studies, the magnetic dipole braking in vacuum is still often assumed. It is shown that the fundamental assumption of magnetic dipole braking(vacuum condition) does not exist and it is not consistent with the observations. The physical torque must consider the presence of the pulsar magnetosphere. Among various efforts, the wind braking model can explain many observations of pulsars and magnetars in a unified way. It is also consistent with the up-to-date observations. It is time for a paradigm shift in pulsar studies: from magnetic dipole braking to wind braking. As one alternative to the magnetospheric model, the fallback disk model is also discussed.