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531.
本文系统阐述了邓小平同志指导党史研究、正确处理历史遗留问题的六大原则"向前看"原则;"宜粗不宜细"原则;"有错必纠"原则;客观性原则;分析个人责任与分析复杂背景相结合的原则;总结成功经验与汲取失败教训相结合的原则.文章深入分析了上述原则的内涵、要求及其意义. 相似文献
532.
本文在基本假设的基础上,探讨了航线客运价格决策分析模型,着重研究了两点之间存在多条旅行路线的条件下,旅客对旅行路线的选择行为与旅行路线经营者的决策行为问题。在经营者独立竞争的情况下,文章从被动决策、预期决策等角度建立了均衡过程模型。在旅客行为研究中,本文得出结论,旅客选择旅行路线决定于他的最大价格边际效用。 相似文献
533.
G.M. Keating D.F. Young 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(7):155-166
Since the publication of the last COSPAR International Reference Atmosphere (CIRA 72), large amounts of ozone data acquired from satellites have become available in addition to increasing quantities of rocketsonde, balloonsonde, Dobson, M83, and Umkehr measurements. From the available archived satellite data, models are developed for the new CIRA using 5 satellite experiments (Nimbus 7 SBUV and LIMS, AEM-2 SAGE, and SME IR and UVS) of the monthly latitudinal and altitudinal variations in the ozone mixing ratio in the middle atmosphere. Standard deviations and interannual variations are also quantified. The satellite models are shown to agree well with a previous reference model based on rocket and balloon measurements. 相似文献
534.
The signal-to-noise ratio of the output of a hard-limiting bandpass limiter to a PM signal is calculated by using the probability density function of the random phase variable. The signal-to-noise ratio transfer characteristics are plotted for comparison. 相似文献
535.
Filter compensation techniques for several special but practical cases are discussed. A general set of bias and covariance equations for linear filters with modeling errors is first summarized. A method for relating the modeling errors to the selection of the covariance of "process noise" for model error compensation is suggested. A performance ordering for cases when the true system becomes a subsystem of the model used for the filter construction is given. A bias correcting filter is derived for the case when the filter is matched only to a subsystem of the actual system. 相似文献
536.
537.
导弹地面测试发射设备研制过程中的可靠性具有重要作用,因此将可靠性与性能设计放在同等重要的位置,两者同步进行,是研制出性能好、可靠性高的地面测试发射设备的关键。 相似文献
538.
R.J.L. Grard L.W. Parker D.T. Young 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):403-407
The surface of a spacecraft is submitted to the bombardment of dust grains and neutral molecules during an atmospheric re-entry or a cometary fly-by. These particles create secondary ions and electrons which form a plasma cloud around the body and control the electric potential of its surface. Computer simulation models are used to predict the structure and dynamic behaviour of the charged particle density distribution for the cases of planar and cylindrical bodies. It is found that an ion and an electron layer form in the vicinity of the surface at distances of the order of the ion and electron Debye lengths, respectively. The potential of the surface is positive on the average and is a function of the electron mean kinetic energy. A positive potential barrier develops at the location of the ion layer and its height is governed by the sum of the electron and ion mean kinetic energies. The threat caused by this interaction to the spacecraft and its instrumentation is discussed and an in-situ observation of this phenomenon is proposed as a possible diagnostic technique of the environment. 相似文献
539.
Tracking a maneuvering target using input estimation versus theinteracting multiple model algorithm 总被引:1,自引:0,他引:1
Bar-Shalom Y. Chang K.C. Blom H.A.P. 《IEEE transactions on aerospace and electronic systems》1989,25(2):296-300
Two maneuvering-target tracking techniques are compared. The first, called input estimation, models the maneuver as constant unknown input, estimates its magnitude and onset time, and then corrects the state estimate accordingly. The second models the maneuver as a switching of the target state model, where the various state models can be of different dimension and driven by process noises of different intensities, and estimates the state according to the interacting multiple model (IMM) algorithm. While the first requires around twenty parallel filters, it is shown that the latter, implemented in the form of the IMM, performs equally well or better with two or three filters 相似文献
540.
Nan Zhang He-sen Tang Jin Chang He-qi Zhang Wei-qun Gan Fu-yuan Gu Qi-zhong Shen Yin-lin Xu Ming-sheng Cai Yi-zhong Gong 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2003,32(12):2579-2583
Preliminary observing achievements by the Super Soft X-ray Detector and the γ-ray Detector in the fields of cosmic gamma-ray bursts, solar X-ray, bursts and cosmic X-ray/γ-ray background radiation are summarized. The detectors are aboard the spacecraft Shenzhou-2 that was launched on 2001 January 10. The scientific mission and general situation of the instruments are briefly described. 相似文献