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961.
The complexity has been evaluated for the devices determined on the basis of the structural pattern proposed, which are implemented on the distributed programmable-architecture computing systems. 相似文献
962.
Basic aspects of constructing multilevel, multidiscipline systems for modeling the airbreathing engine (ABE) units are presented.
A two-level, two-discipline system of afterburner modeling is considered and the numerical modeling results and experimental
data are given for comparison. 相似文献
963.
Retrieval of vegetation equivalent water thickness from reflectance using genetic algorithm (GA)-partial least squares (PLS) regression 总被引:1,自引:0,他引:1
L. Li Y.-B. Cheng S. Ustin X.-T. Hu D. Riao 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(11):1755-1763
This study aimed to investigate the performance of genetic algorithms coupled with partial least squares (GA-PLS) modeling of spectral reflectance in retrieving equivalent water thickness (EWT) at leaf and canopy level. A genetic algorithm was used to identify a subset of spectral bands sensitive to the variation in EWT, and PLS was then applied to relate the identified bands to EWT values. GA-PLS was applied to leaf level reflectance available from LOPEX dataset, and canopy data includes reflectance simulated by a leaf radiative transfer model PROSPECT and a canopy radiative transfer model SAILH and acquired by airborne visible/infrared imaging spectrometer (AVIRIS). The results indicate that GA-PLS has the capability of retrieving EWT from leaf and canopy reflectance, and achieved good estimation accuracy, i.e. low root mean square errors (RMSE) and high squared correlation coefficients (R2). For the retrieval at leaf level, the estimation accuracy can be as good as RMSE = 0.0019 g/cm2 and R2 = 0.939 or better. For the retrieval at canopy level, the model accuracy is RMSE = 0.0061 g/cm2 and R2 = 0.966 or better when PROSPECT-SAILH simulated reflectance was used; when AVIRIS image spectra were used, the model accuracy is RMSE = 0.0094 g/cm2 and R2 = 0.8734 for the calibration, and RMSE = 0.0132 g/cm2 and R2 = 0.7756 for the validation. These results from GA-PLS modeling support the conclusion that GA-PLS has the potential to be applied to AVIRIS, Hyperion and HyMap imagery for retrieving EWT. The selected bands for the AVIRIS datasets differ from those for the LOPEX and PROSPECT-SAILH simulated datasets, and this inconsistence of the selected bands for different datasets indicates that the GA-PLS method has the advantage of tuning the optimum bands for PLS regression and accommodating the effects of confounding factors. 相似文献
964.
乳腺癌是癌症中引起妇女死亡的首要因素。本文采用绿色量子点作为荧光显色材料,建立了一种用于早期乳腺癌诊断的原位成像技术。利用生物素标记的抗HER2/neu抗体与乳腺癌细胞表面表达的HER2结合的特点,然后用偶联绿色量子点的链霉亲和素作为荧光检测标记物,与HER2抗原抗体复合物中的生物素发生特异结合,检测出乳腺癌细胞的存在。结果表明,在荧光显微镜下用绿色量子点原位显色的乳腺癌细胞,相对有机染料组显色亮度增强,故检测灵敏度有所提高。 相似文献
965.
Yu. P. Kataev 《Russian Aeronautics (Iz VUZ)》2010,53(3):328-333
The calculation of the die diameter in the course of sizing taking into account reverse elastic strain of pipes is presented.
Also determined are the necessary pressure value and the stress strain state in the process of tips deformation. 相似文献
966.
O T Demkiv E L Kordyum O R Khorkavtsiv YaDKardash 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(8-9):1191-1195
Moss protonemal growth direction is controlled by at least three factors, photo-, gravi- and autotropism. It is possible to experimentally separate these factors and to control selectively their morphological appearance. In darkness protonema grow negatively gravitropically, and unilateral illumination initiated positive phototropism. Red light suppressed auto- and gravitropism, blue light suppressed only gravitropism. Green light allowed both gravi- and autotropism. The effect of light on gravitropism might involve changes in starch synthesis. 相似文献
967.
The influence of spatial orientation of the International Space Station (ISS) on the dose rate recorded during passages of the station through the South-Atlantic anomaly (SAA) zone is considered. The
dose rates detected by dosimeters of the radiation control system of the ISS are compared with results of calculation-based estimates. It is shown that when crossing the SAA region in close trajectories,
but with different spatial orientation of the station, the dose rate near cabins of the ISS Service Module can differ by more than a factor of two. 相似文献
968.
969.
L. D. Akulenko Ya. S. Zinkevich D. D. Leshchenko A. L. Rachinskaya 《Cosmic Research》2011,49(5):440-451
Rapid rotational motion of a dynamically asymmetric satellite relative to the center of mass is studied. The satellite has
a cavity filled with viscous fluid at low Reynolds numbers, and it moves under the action of moments of gravity and light
pressure forces. Orbital motions with an arbitrary eccentricity are supposed to be specified. The system, obtained after averaging
over the Euler-Poinsot motion and applying the modified averaging method, is analyzed. The numerical analysis in the general
case is performed, and the analytical study in the axial rotation vicinity is carried out. The motion in the specific case
of a dynamically symmetric satellite is considered. 相似文献
970.
Yu. P. Ulybyshev 《Cosmic Research》2010,48(6):534-541
The problem of terminal control over a deorbiting spacecraft at the stage of its flight after leaving plasma (altitude of
∼40 km) is considered, the aim being to guide it to a preset landing point. The algorithm is based on a modification of the
well-known method of proportional navigation, when a fixed point is the target. It is suggested to use satellite navigation
systems (of the GLONASS or GPS types) and/or radio beacons, which should allow one to determine the spacecraft trajectory
parameters with high precision. Single-channel control is performed by changing the roll angle according to current parameters
of the trajectory, which ensures adaptability of the method. Examples of three-dimensional trajectories of flight are presented
for a manned spacecraft with low lift-to-drag ratio (∼0.5), currently under design in Russia. The results of statistical modeling
taking into account initial deviations of the trajectory parameters and wind disturbances are presented. A method of statistical
choice of a reference trajectory for the guidance stage is suggested. A theoretical possibility of using the algorithm of
spacecraft guidance (in case of in-light accident with a carrier launcher) to preset regions in the vicinity of launching
route is demonstrated. A qualitative analysis of proportional navigation with a fixed target is presented. 相似文献