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1.
In this paper, the GRACE Earth’s gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89o inclination can improve effectively the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coefficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89o inclination. Two groups of GRACE individually exploiting 89o+(82o-84o) inclinations are the optimal combination of the Earth’s gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exploiting 89o and 83o inclinations is averagely 2 times higher than the accuracy of a group of GRACE exploiting 89o inclination.  相似文献   

2.
In this paper, the GRACE Earth's gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle. The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees l and orders m, the design of GRACE exploiting 89° inclination can effectively improve the accuracy of geopotential zonal harmonic coefficients. However, it is less sensitive to the geopotential tesseral harmonic coef- ficients. Accordingly, the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89° inclination. Two groups of GRACE individually exploiting 89° + (82°-84°) inclinations are the optimal combination of the Earth's gravitational field recovery complete up to degree and order 120. In the degree 120, the joint accuracy of cumulative geoid height based on two groups of GRACE individually exoloiting 89° and 83° inclinations is averagely two times higher than the accuracy of a group of GRACE exploiting 89~ inclination.  相似文献   

3.
In this paper,the GRACE Earth's gravitational field complete up to degree and order 120 is recovered based on the combination of different inclinations using the energy conservation principle.The results show that because different inclinations of satellite are sensitive to the geopotential coefficients with different degrees/and orders m.the design of GRACE exploiting 89° inclination can effectively improve the accuracy of geopotential zonal harmonic coefficients.However,it is less sensitive to the geopotential tesseral harmonic coefficients.Accordingly.the second group of GRACE exploiting lower inclination is required to determine high-accurately the geopotential tesseral harmonic coefficients and cover the shortage of the single group of GRACE exploiting 89° inclination.Two groups of GRACE individually exploiting 89° (82°-84°)inclinations are the optimal combination of the Earth'S gravitational field recovery complete up to degree and order 120.In the degree 120,the joint accuracy of cumulative geoid height based on two groups of GRACE individually exploiting 89° and 83° inclinations is averagely two times higher than the accuracy of a group of GRACE exploiting 89° inclination.  相似文献   

4.
Based on the measurement principles of GRACE satellites, the observation equations are set up using the energy balance approach. The Earth's gravitational field complete up to degree and order 120 is recovered applying the preconditioning conjugate gradient iterative approach by numerical simulation. Assuming an accuracy of 1 μms in range-rate measurements of the K-band microwave ranging system, the matching relationships of accuracies of K-band microwave ranging system, SuperSTAR Accelerometer, position vector and velocity vector measurements are investigated.  相似文献   

5.
In a genome the set of proteins are formed by duplication and combination of domain superfamilies. P-loop containing nucleotide triphosphate (NTP) hydrolases superfamily is massively duplicated and has the most different partner superfamilies among archaea, bacteria and eukarya, Here, we study the distributions of duplication and combination of p-loop containing NTP hydrolases superfamily in 169 completed genomes. When the total number of domains in a genome is larger, duplication and combination partners of p-loop conraining NTP hydrolases are more. This phenomenon is more obvious in metazoa. The distributions of abundance and corn bination of partners relate to the functions of the protein. Those distributions in metazoa are very different from those in other kingdoms because of complexity of metazoa. Finally the relationship between duplication and combination of p-loop containing NTP hydrolases superfamily in different genomes is described. It fits a power law.  相似文献   

6.
Constructing a mathematic transfer function of pollen and climatic factors is one of the most important approaches in the quantitative reconstruction of paleoclimate elements.In the function building,the key point is the response sensitivity to the climate change for different pollen families and categories. As an example in this paper,the pollen samples from the surface and stratum in Dajiuhu basin,Shennongjia are used to estimate the sensitivity of pollen factor-temperature in the transfer function by the EOF analysis,multiple regression and stepwise regression techniques.Thereafter,the selection methods of pollen factors are discussed and compared with other results from different researchers. The results show that in the pollen samples,the quantity of woody plants is larger than others,but the woody plants have relatively lower sensitivity and slow responses to the climate evolution and abrupt climate change.While the pollens from lower grade plants(herb and fern)have a relatively high sensi- tivity to the temperature change and fast response to the abrupt climate changes.Therefore,the pollen of herb and fern may significantly record the extreme events in the climate change.Also in different regions,the pollen samples have different sensitivity and optimum combination in the transfer functions.Final conclusion is that the stepwise regression is one of the best methods for transfer function building since it can obtain the maximum multiple correlation coefficients and optimum combination of sensitive pollen factors.  相似文献   

7.
Under the underdetermined blind sources separation ( UBSS) circumstance, it is difficult to es-timate the mixing matrix with high-precision because of unknown sparsity of signals.The mixing ma-trix estimation is proposed based on linear aggregation degree of signal scatter plot without knowing sparsity, and the linear aggregation degree evaluation of observed signals is presented which obeys generalized Gaussian distribution ( GGD) .Both the GGD shape parameter and the signals’ correla-tion features affect the observation signals sparsity and further affected the directionality of time-fre-quency scatter plot.So a new mixing matrix estimation method is proposed for different sparsity de-grees, which especially focuses on unclear directionality of scatter plot and weak linear aggregation degree.Firstly, the direction of coefficient scatter plot by time-frequency transform is improved and then the single source coefficients in the case of weak linear clustering is processed finally the im-proved K-means clustering is applied to achieve the estimation of mixing matrix.The proposed algo-rithm reduces the requirements of signals sparsity and independence, and the mixing matrix can be estimated with high accuracy.The simulation results show the feasibility and effectiveness of the al-gorithm.  相似文献   

8.
This paper deals with the experimental study on the correlation between insulation resistance (R) and direct current (DC) component (idc) and corresponding aging degree of insulation in the course of the aging within cross linked polyethylene (XLPE) insulation. The aging tests were performed on a section of 10 kV transmission XLPE cable by means of water needle method, and R was measured by dc voltage superimposed method. R and idc were found to be significantly dependent on the corresponding aging degree of insulation in the course of aging of XLPE, and different kind of aging stage has different characteristics. Beside, there are generally similar regularity but different amplitude in the course of aging of XLPE insulation in different electrolyte, and the various electrochemical tree were found on the surface of aging XLPE cable immersed in CuSO, solution. Therefore. according to the changing regularity of the DC characteristic parameters i.e. R and idc within XLPE insulation judging the aging degree of XLPE insulation will be an effective method.  相似文献   

9.
Due to different cultural and historical background, the technology in Western and Eastern pattern design is inherently different. Along with the development of technology, garment pattern design technique is making progress towards high effectiveness and accuracy. Many researchers proposed different alternative methodologies to improve the current pattern making processes. This article examines the development of Western and Eastern garment pattern design technique. The main objective of this article is to provide a thorough review and hence a better understanding to those researchers who made contribution on developing pattern design technique and continue their work in the future.  相似文献   

10.
An artificial neural network is used to predict the performance of fabrics in clothing manufacturing. The predictions are based on fabric mechanical properties measured on the FAST system. The influences of the different ANN‘s construct on the convergence speed and the prediction accuracy are investigated. The result indicates that the BP neural network is an efficiency technique and has a wide prospect in the application to garment processing.  相似文献   

11.
This paper deals with the experimental study on the correlation between partial discharge (PD) characteristic parameters and corresponding aging degree of insulation in the course of the aging within eros,s-linked polyethylene (XLPE) insulation. The aging tests were performed on a section of 10 kV transmission cable by means of water needle method. The PD macroscopic characteristic parameters were found to be significantly dependent on the corresponding aging degree of insulation in the course of aging of XLPE, and different kind of aging stage has different characteristics. Beside, there are similar regularity but different PD amplitude in the course of aging of XI.PE insulation in different electrolyte, and their insulation life is different. Therefore, according to the chan ging regularity of the PD macroscopic characteristic parame ters within XLPE insulation judging the aging degree of XLPE insulation will be an effective method.  相似文献   

12.
A fast algorithm is presented to invert the structure parameter of the horizontal multi-layer soil. The procedure is divided into two independent stages. First, Fredholm equation of the first kind with respect to the apparent resistivity is solved by the technology of decay spectrum to reduce computation time greatly. Second, the structure parameter of soil is determined by the generalized Newton-Kantorovich method, which is more robust and less noise sensitive because of using the generalized inverse algorithm to solve the nonlinear equation group. The numerical results show the validities and main features of the proposed approach.  相似文献   

13.
A new method for image segmentation based on pulse neural network is proposed. Every neuron in the network represents one pixel in the image and the network is locally connected. Each group of the neurons that correspond to each object synchronizes while different groups of the neurons oscillate at different period. Applying this period difference, different objects are divided. In addition to simulation, an analysis of the mechanism of the method is presented in this paper.  相似文献   

14.
Based on the tests of eight kinds of typical fabrics, the relation between the drape coefficient of different fabrics and its revolving speed was analyzed and discussed. The result of regression curve fitting of experimental data showed that the relation between drape coefficient of fabric and its revolving speed could be expressed by negative exponential equation. Meanwhile, the difference of drape coefficients between static and dynamic at 100 - ISOr.p.m was suggested to be one of the expressing parameters of the lively degree of fabric dynamic drape.  相似文献   

15.
付宜利  Xu  He  Li  Han  Wang  Shuguo  Ma  Yuliu 《高技术通讯(英文版)》2006,12(3):245-249
An irmovative mobile robot that has reconfigurable loeomotion chassis and reconfigurable bionic wheels has been developed to meet the needs of different payload and different terrain. Several prototypes have been achieved by the recortfiguration. By modeling relative comparison coefficients, these prototypes are analyzed in terms of geometrical parameter of trafficability, static stability and maneuverability. The effects of reconfiguration on these indices of robot performance can be compared, i.e. the variable height of chassis h has the biggest effect, the variable length of chassis 1 is the second, then is the camber angle β and the caster angle α. Some principles for reconfiguration are proposed.  相似文献   

16.
It is investigable how the system scaling affects the system complexity degree. The traffic flow system is taken in this paper as an illustration to study this question. First, the Lempel-Ziv algorithm is introduced for accurate depiction of the complexity degree of the traffic flow system. We gain 3 actual sequences and 20 s period traffic flow sequences on the basis of the measure of the traffic flow data; we gain 5 traffic flow sequences whose periods are between 1 - 5 min by simulating the traffic flow system. By calculating the complicacy of the 11 sequences, we obtain two hypothesis: the complicacies of the same system are different under different time scalings; negative correlation exists between the complicacy and the time scaling of the system.  相似文献   

17.
Micropipe and step structures on 6H-SiC (0001) surface were investigated by an atomic force microscopy (AFM). On the facet,all micropipes examined are the origins of spiral steps,indicating that dislocations intersect the surface at these points. Micropipes are empty-core super-dislocations as originally described by Frank. The micropipe radius increases with the square of the dislocation Burgers vector. From the center to the periphery,step structures change with different surface inclinations. Regular step is observed within the central faceted area. Step bunching and atomically rough surfaces are observed within the peripheral convex area. If the inclination with respect to the (0001) plane is large enough,step bunching of 15R-SiC can be observed.  相似文献   

18.
A novel wavelet-based algorithm for image enhancement is proposed in the paper. On the basis of multiscale analysis, the proposed algorithm solves efficiently the problem of noise over-enhancement, which commonly occurs in the traditional methods for contrast enhancement. The decomposed coefficients at same scales are processed by a nonlinear method, and the coefficients at different scales are enhanced in different degree. During the procedure, the method takes full advantage of the properties of Human visual system so as to achieve better performance. The simulations demonstrate that these characters of the proposed approach enable it to fully enhance the content in images, to efficiently alleviate the enhancement of noise and to achieve much better enhancement effect than the traditional approaches.  相似文献   

19.
The original idea of orbit determination called "determination of satellite orbit by transfer" was proposed by the National Time Service Center,Chinese Academy of Sciences.It shows that the system is very stable and the orbit determination accuracy is improved greatly.A new observation mode called "differenced ranges between master station and slave stations by transfer" is introduced.It is the development of "determination of satellite orbit by transfer".In principle,the differenced ranges between master station and slave stations have a high angular resolution,and strongly constrains in the transverse direction of satellite orbit,perpendicular to the line-of-sight.The principle of "differenced ranges between master station and slave stations by transfer" is discussed in detail.And differenced ranges in combination with ranging data were used to determine satellite’s orbit and orbit prediction under different arc observations.It shows that orbit determination accuracy for orbit prediction can be improved with differenced ranges in combination with ranging data.  相似文献   

20.
This paper proposed an algorithm in which the maximum probability and the weighted average strategy were used for the combination of member classifiers. Using parallel computing, we test the algorithm on a China-Brazil Earth Resources Satellite (CBERS) image for land cover classification. The results show that using three computers in parallel can reduce the classification time by 30%, as compared with using only one computer with a dual core processor. The accuracy of the final image is 93.34%, and Kappa is 0.92. Multiple classifier combination can enhance the precision of the image classification, and parallel computing can increase the speed of calculation so that it becomes possible to process remote sensing images with high efficiency and accuracy.  相似文献   

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