In order to improve Chinese overlapping ambiguity resolution based on a support vector machine, statistical features are studied for representing the feature vectors. First, four statistical parameters-mutual informat...In order to improve Chinese overlapping ambiguity resolution based on a support vector machine, statistical features are studied for representing the feature vectors. First, four statistical parameters-mutual information, accessor variety, two-character word frequency and single-character word frequency are used to describe the feature vectors respectively. Then other parameters are tried to add as complementary features to the parameters which obtain the best results for further improving the classification performance. Experimental results show that features represented by mutual information, single-character word frequency and accessor variety can obtain an optimum result of 94. 39%. Compared with a commonly used word probability model, the accuracy has been improved by 6. 62%. Such comparative results confirm that the classification performance can be improved by feature selection and representation.展开更多
Due to the different signal frequencies for the GLONASS satellites,the commonly-used double-differencing procedure for carrier phase data processing can not be implemented in its straightforward form,as in the case of...Due to the different signal frequencies for the GLONASS satellites,the commonly-used double-differencing procedure for carrier phase data processing can not be implemented in its straightforward form,as in the case of GPS.In this paper a novel data processing strategy,involving a three-step procedure,for integrated GPS/GLONASS positioning is proposed.The first is pseudo-range-based positioning,that uses double-differenced (DD) GPS pseudo-range and single-differenced (SD) GLONASS pseudo-range measurements to derive the initial position and receiver clock bias.The second is forming DD measurements (expressed in cycles) in order to estimate the ambiguities,by using the receiver clock bias estimated in the above step.The third is to form DD measurements (expressed in metric units) with the unknown SD integer ambiguity for the GLONASS reference satellite as the only parameter (which is constant before a cycle slip occurs for this satellite).A real-time stochastic model estimated by residual series over previous epochs is proposed for integrated GPS/GLONASS carrier phase and pseudo-range data processing.Other associated issues,such as cycle slip detection,validation criteria and adaptive procedure(s) for ambiguity resolution,is also discussed.The performance of this data processing strategy will be demonstrated through case study examples of rapid static positioning and kinematic positioning.From four experiments carried out to date,the results indicate that rapid static positioning requires 1 minute of single frequency GPS/GLONASS data for 100% positioning success rate.The single epoch positioning solution for kinematic positioning can achieve 94.6% success rate over short baselines (<6 km).展开更多
In this paper, we propose a modified traffic model in which a single car moves through a sequence of traffic lights controlled by a step function instead of a sine function. In contrast to the previous work [Phys. Rev...In this paper, we propose a modified traffic model in which a single car moves through a sequence of traffic lights controlled by a step function instead of a sine function. In contrast to the previous work [Phys. Rev. E 70 （2004） 016107], we have investigated in detail the dependence of the behavior on four parameters, ω,α,η and α1, and given three kinds of bifurcation diagrams, which show three kinds of complex behaviors. We have found that in this model there are chaotic and complex periodic motions, as well as special singularities. We have also analyzed the characteristic of the complex period motion and the essential feature of the singularity.展开更多
The aim of this paper is to put forward the explanatory factors of the participation of women in the economic activity in the Cameroonian context characterized by an important and persistent gender gap in terms of par...The aim of this paper is to put forward the explanatory factors of the participation of women in the economic activity in the Cameroonian context characterized by an important and persistent gender gap in terms of participation in the economic activity （more men than women）. The authors carried out, on the basis of data resulting from the DHS-MICS 2011, an analysis using the binomial logistic model. It comes out from this analysis that the significant explanatory variables are the age （which plays at the same time the role of variable of control）, the religion, the ethnic group, the size of the household, the relationship with the head of household, the educational level （of the woman and the husband/partner）, the occupational status of the husband/partner, the household＇s standard of living, and the marital status. According to the results obtained, it would be important to set up policies intended to reinforce the professionalization of the young woman and to fight against the sexist sociocultural norms and practices advocating the ＂sexual division＂ of labor.展开更多
In this paper, a periodic Holling Ⅱ predator-prey model with impulsive effect is investigated. By applying the Floquet theory of linear periodic impulsive equation,some sufficient conditions are obtained for the line...In this paper, a periodic Holling Ⅱ predator-prey model with impulsive effect is investigated. By applying the Floquet theory of linear periodic impulsive equation,some sufficient conditions are obtained for the linear stability and instability of trivial and semi-trivial periodic solutions. Moreover, we use standard bifurcation theory to show the existence of coexistence states which arise near the semi-trivial periodic solution. As an application, we also examine some special case of the system to confirm our main results.展开更多
In this paper, time series with stable convergence, saddles, Hopf bifurcations and chaotic points in one kind of complicated systems have been studied in respects of： fractal characteristic and fractal dimension. By ...In this paper, time series with stable convergence, saddles, Hopf bifurcations and chaotic points in one kind of complicated systems have been studied in respects of： fractal characteristic and fractal dimension. By using phase space reconstruction technology of chaotic time series, work of reconstruction has been done respectively on these four different conditions and further by applying wavelet network models, work of modeling and prediction have been done accordingly. The results indicate： treatment of zero mean value in the identification of the chaotic models has no obvious influence on precision and length of predictions, while the treatment by Fourier Filter can damage effectiveness of prediction.展开更多
文摘In order to improve Chinese overlapping ambiguity resolution based on a support vector machine, statistical features are studied for representing the feature vectors. First, four statistical parameters-mutual information, accessor variety, two-character word frequency and single-character word frequency are used to describe the feature vectors respectively. Then other parameters are tried to add as complementary features to the parameters which obtain the best results for further improving the classification performance. Experimental results show that features represented by mutual information, single-character word frequency and accessor variety can obtain an optimum result of 94. 39%. Compared with a commonly used word probability model, the accuracy has been improved by 6. 62%. Such comparative results confirm that the classification performance can be improved by feature selection and representation.
文摘Due to the different signal frequencies for the GLONASS satellites,the commonly-used double-differencing procedure for carrier phase data processing can not be implemented in its straightforward form,as in the case of GPS.In this paper a novel data processing strategy,involving a three-step procedure,for integrated GPS/GLONASS positioning is proposed.The first is pseudo-range-based positioning,that uses double-differenced (DD) GPS pseudo-range and single-differenced (SD) GLONASS pseudo-range measurements to derive the initial position and receiver clock bias.The second is forming DD measurements (expressed in cycles) in order to estimate the ambiguities,by using the receiver clock bias estimated in the above step.The third is to form DD measurements (expressed in metric units) with the unknown SD integer ambiguity for the GLONASS reference satellite as the only parameter (which is constant before a cycle slip occurs for this satellite).A real-time stochastic model estimated by residual series over previous epochs is proposed for integrated GPS/GLONASS carrier phase and pseudo-range data processing.Other associated issues,such as cycle slip detection,validation criteria and adaptive procedure(s) for ambiguity resolution,is also discussed.The performance of this data processing strategy will be demonstrated through case study examples of rapid static positioning and kinematic positioning.From four experiments carried out to date,the results indicate that rapid static positioning requires 1 minute of single frequency GPS/GLONASS data for 100% positioning success rate.The single epoch positioning solution for kinematic positioning can achieve 94.6% success rate over short baselines (<6 km).
基金Prof. Z.R. Yang provided helpful guidance to this work. We are very thankful to Prof. Z.R. Yang and grateful to Profs. Z.G. Zheng, Z. Gao, and W.A. Guo, who provided many good suggestions to this work. We also acknowledge fruitful discussions with Drs. J.X. Le, X,M, Kong, X,H, Li, and J.Q. Tao.
文摘In this paper, we propose a modified traffic model in which a single car moves through a sequence of traffic lights controlled by a step function instead of a sine function. In contrast to the previous work [Phys. Rev. E 70 （2004） 016107], we have investigated in detail the dependence of the behavior on four parameters, ω,α,η and α1, and given three kinds of bifurcation diagrams, which show three kinds of complex behaviors. We have found that in this model there are chaotic and complex periodic motions, as well as special singularities. We have also analyzed the characteristic of the complex period motion and the essential feature of the singularity.
文摘The aim of this paper is to put forward the explanatory factors of the participation of women in the economic activity in the Cameroonian context characterized by an important and persistent gender gap in terms of participation in the economic activity （more men than women）. The authors carried out, on the basis of data resulting from the DHS-MICS 2011, an analysis using the binomial logistic model. It comes out from this analysis that the significant explanatory variables are the age （which plays at the same time the role of variable of control）, the religion, the ethnic group, the size of the household, the relationship with the head of household, the educational level （of the woman and the husband/partner）, the occupational status of the husband/partner, the household＇s standard of living, and the marital status. According to the results obtained, it would be important to set up policies intended to reinforce the professionalization of the young woman and to fight against the sexist sociocultural norms and practices advocating the ＂sexual division＂ of labor.
基金This research is supported by the National Natural Science Foundation of China (10171106).
文摘In this paper, a periodic Holling Ⅱ predator-prey model with impulsive effect is investigated. By applying the Floquet theory of linear periodic impulsive equation,some sufficient conditions are obtained for the linear stability and instability of trivial and semi-trivial periodic solutions. Moreover, we use standard bifurcation theory to show the existence of coexistence states which arise near the semi-trivial periodic solution. As an application, we also examine some special case of the system to confirm our main results.
基金This project is supported by National Natural Science Foundation of China （70271071）, Education department of Tianjin （20041702）
文摘In this paper, time series with stable convergence, saddles, Hopf bifurcations and chaotic points in one kind of complicated systems have been studied in respects of： fractal characteristic and fractal dimension. By using phase space reconstruction technology of chaotic time series, work of reconstruction has been done respectively on these four different conditions and further by applying wavelet network models, work of modeling and prediction have been done accordingly. The results indicate： treatment of zero mean value in the identification of the chaotic models has no obvious influence on precision and length of predictions, while the treatment by Fourier Filter can damage effectiveness of prediction.
