The diagnostic characters of Arge nipponensis group and Arge mali group are briefly discussed. Two new species of Argidae are described from China: Arge wanziae Wei sp. nov. and Arge listoni Wei sp. nov. Arge wanziae ...The diagnostic characters of Arge nipponensis group and Arge mali group are briefly discussed. Two new species of Argidae are described from China: Arge wanziae Wei sp. nov. and Arge listoni Wei sp. nov. Arge wanziae is a member of the Arge nipponensis group and A. listoni is a member of Arge mali group.展开更多
Let H be a Hopf algebra and B an algebra with two linear maps δ, τ: H H→B. The necessary and sufficient conditions for the twisted crossed product B#^τδH equipped with the tensor product coalgebra structure to b...Let H be a Hopf algebra and B an algebra with two linear maps δ, τ: H H→B. The necessary and sufficient conditions for the twisted crossed product B#^τδH equipped with the tensor product coalgebra structure to be a bialgebra are proved. Then, B#^τδH is a coquasitriangular Hopf algebra under certain conditions. This coquasitriangular Hopf algerbra generalizes some known cross products. Finally, as an application, an explicit example is given.展开更多
A new species of Argidae is described from Zhejiang, China: Athermantus melanoptera Wei sp. nov. This new species is similar to A. leucopilosus Wen & Wei, 2002, but differs from it by the body hairs black;the uppe...A new species of Argidae is described from Zhejiang, China: Athermantus melanoptera Wei sp. nov. This new species is similar to A. leucopilosus Wen & Wei, 2002, but differs from it by the body hairs black;the upper of hind orbit clearly broader than eye in lateral view;pterostigma entirely black;vein R of fore wing clearly shorter than vein R+M;valviceps of penis valve narrow and hardly oblique, about 3.5 times as long as broad. A key to species of Athermantus Kirby, 1882 is also provided.展开更多
Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were establi...Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams.展开更多
This paper studies the Generalized Bretherton equation using trigonometric function method including the sech-function method, the sine-cosine function method, and the tanh-function method, and He's semi-inverse meth...This paper studies the Generalized Bretherton equation using trigonometric function method including the sech-function method, the sine-cosine function method, and the tanh-function method, and He's semi-inverse method (He's variational method). Various traveling wave solutions are obtained, revealing an intrinsic relationship among the amplitude, frequency, and wave speed.展开更多
From the mathematical principles, the generalized potential theory can be employed to create constitutive model of geomaterial directly. The similar Cam-clay model, which is created based on the generalized potential ...From the mathematical principles, the generalized potential theory can be employed to create constitutive model of geomaterial directly. The similar Cam-clay model, which is created based on the generalized potential theory, has less assumptions,clearer mathematical basis, and better computational accuracy. Theoretically, it is more scientific than the traditional Cam-clay models. The particle flow code PFC3 D was used to make numerical tests to verify the rationality and practicality of the similar Cam-clay model. The verification process was as follows: 1) creating the soil sample for numerical test in PFC3 D, and then simulating the conventional triaxial compression test, isotropic compression test, and isotropic unloading test by PFC3D; 2)determining the parameters of the similar Cam-clay model from the results of above tests; 3) predicting the sample's behavior in triaxial tests under different stress paths by the similar Cam-clay model, and comparing the predicting results with predictions by the Cam-clay model and the modified Cam-clay model. The analysis results show that the similar Cam-clay model has relatively high prediction accuracy, as well as good practical value.展开更多
In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)i...In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.展开更多
A general mapping deformation method is presented and applied to a (2+1)-dimensional Boussinesq system. Many new types of explicit and exact travelling wave solutions, which contain solitary wave solutions, periodic w...A general mapping deformation method is presented and applied to a (2+1)-dimensional Boussinesq system. Many new types of explicit and exact travelling wave solutions, which contain solitary wave solutions, periodic wave solutions, Jacobian and Weierstrass doubly periodic wave solutions, and other exact excitations like polynomial solutions, exponential solutions, and rational solutions, etc., are obtained by a simple algebraic transformation relation between the (2+1)-dimensional Boussinesq equation and a generalized cubic nonlinear Klein-Gordon equation.展开更多
The paper deals with the urban space of Piazza del Governo in Enna, a town located in the center of Sicily. This square was realized in 1935 by the architect Salvatore Caronia Roberti and is representative of the 1930...The paper deals with the urban space of Piazza del Governo in Enna, a town located in the center of Sicily. This square was realized in 1935 by the architect Salvatore Caronia Roberti and is representative of the 1930s' fascist regime. The aim of this research is the knowledge of this urban space: the historical references, the compositive choices, the planimetric layout and its geometric rigor, and the monumentality and representativeness of the buildings overlooking the square. The research used the tools of Survey and Representation to better understand the dimensional ratios both at the urban and architectural scale. We have carried out an integrated survey (direct, photogrammetric, 3D laser scanning) in order to acquire a whole set of information essential to describe, document, and appreciate all the features of this urban space. Our investigation started by analyzing the historical documents preserved at the Historic Archive of the city of Enna (project drawings, letters, and historical images) to better understand why some decisions have been taken. The final result represents the historical memory up-to-date of the whole urban space, and it allows any academics to investigate more about the project: the initial decisions, the conservation state, and the possible and more coherent interventions of maintenance and preservation.展开更多
In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the az...In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the azimuth and elevation planes in an environment where uniformly distributed scatterers are assumed to be present in hemispheroids around the base station(BS) and mobile station(MS). Using this channel model, we first derive the closed-form expression for the joint and marginal probability density functions of the angle-of-arrival and time-of-arrival measured at the BS and the MS corresponding to the azimuth and elevation angles. Next, we derive an expression for the Doppler spectral distribution caused by motion of the MSs. Furthermore, we analyze the performance of multiple-input multiple-output antenna systems numerically. The results show that the proposed 3D scattering channel model performs better than previously proposed two-dimensional(2D) models for indoor and outdoor environments. We compare the results with previous scattering channel models and measurement results to validate the generalizability of our model.展开更多
This study analyzed the determinants of adoption of agricultural extension of Green River Project among rural households of Niger Delta, Nigeria. Questionnaire, which was randomly distributed, was used for data collec...This study analyzed the determinants of adoption of agricultural extension of Green River Project among rural households of Niger Delta, Nigeria. Questionnaire, which was randomly distributed, was used for data collection from 270 direct beneficiaries of the project. Frequency, percentage and multiple regression were used for data analyses. For the beneficiaries, the results indicated a mean age of 48 years, 9 years of formal education, annual net farm income of N115, 681.48 and 2.8 times of monthly contact with Project Extension Officers. The mean adoption status of the project was 56.6%. The relationship between socio-economic characteristics of beneficiaries and adoption status gave an R2 of 0.668. Age, education, farming, experience, farm income and extension contact were significant determinants of adoption. The study recommends improvement in formal education, farm income, extension contact and inclusion of younger farmers as beneficiaries to enhance adoption status.展开更多
Generalized Steiner triple systems, GS(2, 3, n, g) are equivalent to (g+1)-ary maximum constant weight codes (n, 3,3)s. In this paper, it is proved that the necessary conditions for the existence of a GS(2,3, n, 10), ...Generalized Steiner triple systems, GS(2, 3, n, g) are equivalent to (g+1)-ary maximum constant weight codes (n, 3,3)s. In this paper, it is proved that the necessary conditions for the existence of a GS(2,3, n, 10), namely, n ≡ 0,1 (mod 3) and n ≥ 12, are also sufficient.展开更多
In this article, we construct abundant exact traveling wave solutions involving free parameters to the generalized Bretherton equation via the improved (G′/G)-expansion method. The traveling wave solutions are presen...In this article, we construct abundant exact traveling wave solutions involving free parameters to the generalized Bretherton equation via the improved (G′/G)-expansion method. The traveling wave solutions are presented in terms of the trigonometric, the hyperbolic, and rational functions. When the parameters take special values, the solitary waves are derived from the traveling waves.展开更多
In this paper,a new version of the general form of the main inequality of Reich-Strebel is given.As applications,we improve the strong triangle inequality and generalize the Delta inequality in certain sense.
For integers b and c the generalized central trinomial coefficient Tn(b,c)denotes the coefficient of xnin the expansion of(x2+bx+c)n.Those Tn=Tn(1,1)(n=0,1,2,...)are the usual central trinomial coefficients,and Tn(3,2...For integers b and c the generalized central trinomial coefficient Tn(b,c)denotes the coefficient of xnin the expansion of(x2+bx+c)n.Those Tn=Tn(1,1)(n=0,1,2,...)are the usual central trinomial coefficients,and Tn(3,2)coincides with the Delannoy number Dn=n k=0n k n+k k in combinatorics.We investigate congruences involving generalized central trinomial coefficients systematically.Here are some typical results:For each n=1,2,3,...,we have n-1k=0(2k+1)Tk(b,c)2(b2-4c)n-1-k≡0(mod n2)and in particular n2|n-1k=0(2k+1)D2k;if p is an odd prime then p-1k=0T2k≡-1p(mod p)and p-1k=0D2k≡2p(mod p),where(-)denotes the Legendre symbol.We also raise several conjectures some of which involve parameters in the representations of primes by certain binary quadratic forms.展开更多
The particle breakage during specimen compaction had more significant influence on the position of the breakage critical-state line(BCSL)of Tacheng rockfill material(TRM)in the e-lnp’plane than the particle breakage ...The particle breakage during specimen compaction had more significant influence on the position of the breakage critical-state line(BCSL)of Tacheng rockfill material(TRM)in the e-lnp’plane than the particle breakage during shearing,based on the large-scale triaxial compression tests on TRM in a wide range of densities and pressures.The state-dependent dilatancy and the plastic modulus were correlated to the breakage index,based on the formulations of the BCSL of TRM in the e-lnp’plane.The state-dependent model considering particle breakage was proposed for TRM within the framework of the generalized plasticity theory.The proposed model contained fourteen material constants.The test data of TRM from Group A were adopted to determine these material constants,while the test data from Group B were used independently to validate the model predictive capacity.The comparisons between model simulations and test data illustrated that the model with consideration of particle breakage could well represent the stress-strain behaviors of TRM,e.g.,the strain hardening and volumetric contraction behaviors at a loose state and the strain softening and volumetric expansion behaviors at a dense state,and also the particle breakage behaviors of TRM.展开更多
Soil salinity is one of the most severe environmental problems worldwide. It is necessary to develop a soil-salinity-estimation model to project the spatial distribution of soil salinity. The aims of this study were t...Soil salinity is one of the most severe environmental problems worldwide. It is necessary to develop a soil-salinity-estimation model to project the spatial distribution of soil salinity. The aims of this study were to use remote sensed images and digital elevation model(DEM) to develop quantitative models for estimating soil salinity and to investigate the influence of vegetation on soil salinity estimation. Digital bands of Landsat Thematic Mapper(TM) images, vegetation indices, and terrain indices were selected as predictive variables for the estimation. The generalized additive model(GAM) was used to analyze the quantitative relationship between soil salt content, spectral properties, and terrain indices. Akaike's information criterion(AIC) was used to select relevant predictive variables for fitted GAMs. A correlation analysis and root mean square error between predicted and observed soil salt contents were used to validate the fitted GAMs. A high ratio of explained deviance suggests that an integrated approach using spectral and terrain indices with GAM was practical and efficient for estimating soil salinity. The performance of the fitted GAMs varied with changes in vegetation cover.Salinity in sparsely vegetated areas was estimated better than in densely vegetated areas. Visible red and near-infrared bands, and the second and third components of the tasseled cap transformation were the most important spectral variables for the estimation. Variable combinations in the fitted GAMs and their contribution varied with changes in vegetation cover. The contribution of terrain indices was smaller than that of spectral indices, possibly due to the low spatial resolution of DEM. This research may provide some beneficial references for regional soil salinity estimation.展开更多
基金This research was partly supported by the National Natural Science Foundation of China(31672344,31501885).
文摘The diagnostic characters of Arge nipponensis group and Arge mali group are briefly discussed. Two new species of Argidae are described from China: Arge wanziae Wei sp. nov. and Arge listoni Wei sp. nov. Arge wanziae is a member of the Arge nipponensis group and A. listoni is a member of Arge mali group.
文摘Let H be a Hopf algebra and B an algebra with two linear maps δ, τ: H H→B. The necessary and sufficient conditions for the twisted crossed product B#^τδH equipped with the tensor product coalgebra structure to be a bialgebra are proved. Then, B#^τδH is a coquasitriangular Hopf algebra under certain conditions. This coquasitriangular Hopf algerbra generalizes some known cross products. Finally, as an application, an explicit example is given.
基金partly supported by the National Natural Science Foundation of China (31672344, 31501885)
文摘A new species of Argidae is described from Zhejiang, China: Athermantus melanoptera Wei sp. nov. This new species is similar to A. leucopilosus Wen & Wei, 2002, but differs from it by the body hairs black;the upper of hind orbit clearly broader than eye in lateral view;pterostigma entirely black;vein R of fore wing clearly shorter than vein R+M;valviceps of penis valve narrow and hardly oblique, about 3.5 times as long as broad. A key to species of Athermantus Kirby, 1882 is also provided.
基金Project(50708112) supported by the National Natural Science Foundation of ChinaProject(IRT1296) supported by the Program for Changjiang Scholars and Innovative Research Team in University
文摘Slip of a composite box beam may reduce its stiffness, enlarge its deformation and affect its performance. In this work, the governing differential equations and boundary conditions of composite box beams were established. Analytic solutions of combined differential equations were also established. Partial degree of freedom was adopted to establish a new FEA element of three-dimensional beam, taking into account the slip effect. Slip and its first-order derivative were introduced into the nodes of composite box beams as generalized degree of freedom. Stiffness matrix and load array of beam elements were established. A three-dimensional nonlinear calculation program was worked out. The results show that the element is reliable and easy to divide and is suitable for special nonlinear analysis of large-span composite box beams.
文摘This paper studies the Generalized Bretherton equation using trigonometric function method including the sech-function method, the sine-cosine function method, and the tanh-function method, and He's semi-inverse method (He's variational method). Various traveling wave solutions are obtained, revealing an intrinsic relationship among the amplitude, frequency, and wave speed.
基金Projects(51378131,51378403)supported by the National Natural Science Foundation of ChinaProject(2012210020203)supported by the Fundamental Research Funds for the Central Universities,China
文摘From the mathematical principles, the generalized potential theory can be employed to create constitutive model of geomaterial directly. The similar Cam-clay model, which is created based on the generalized potential theory, has less assumptions,clearer mathematical basis, and better computational accuracy. Theoretically, it is more scientific than the traditional Cam-clay models. The particle flow code PFC3 D was used to make numerical tests to verify the rationality and practicality of the similar Cam-clay model. The verification process was as follows: 1) creating the soil sample for numerical test in PFC3 D, and then simulating the conventional triaxial compression test, isotropic compression test, and isotropic unloading test by PFC3D; 2)determining the parameters of the similar Cam-clay model from the results of above tests; 3) predicting the sample's behavior in triaxial tests under different stress paths by the similar Cam-clay model, and comparing the predicting results with predictions by the Cam-clay model and the modified Cam-clay model. The analysis results show that the similar Cam-clay model has relatively high prediction accuracy, as well as good practical value.
基金National Natural Science Foundation of China(Nos.51767013,52067013)。
文摘In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.
文摘A general mapping deformation method is presented and applied to a (2+1)-dimensional Boussinesq system. Many new types of explicit and exact travelling wave solutions, which contain solitary wave solutions, periodic wave solutions, Jacobian and Weierstrass doubly periodic wave solutions, and other exact excitations like polynomial solutions, exponential solutions, and rational solutions, etc., are obtained by a simple algebraic transformation relation between the (2+1)-dimensional Boussinesq equation and a generalized cubic nonlinear Klein-Gordon equation.
文摘The paper deals with the urban space of Piazza del Governo in Enna, a town located in the center of Sicily. This square was realized in 1935 by the architect Salvatore Caronia Roberti and is representative of the 1930s' fascist regime. The aim of this research is the knowledge of this urban space: the historical references, the compositive choices, the planimetric layout and its geometric rigor, and the monumentality and representativeness of the buildings overlooking the square. The research used the tools of Survey and Representation to better understand the dimensional ratios both at the urban and architectural scale. We have carried out an integrated survey (direct, photogrammetric, 3D laser scanning) in order to acquire a whole set of information essential to describe, document, and appreciate all the features of this urban space. Our investigation started by analyzing the historical documents preserved at the Historic Archive of the city of Enna (project drawings, letters, and historical images) to better understand why some decisions have been taken. The final result represents the historical memory up-to-date of the whole urban space, and it allows any academics to investigate more about the project: the initial decisions, the conservation state, and the possible and more coherent interventions of maintenance and preservation.
基金supported by the National Nature Science Foundation of China (No.61471153)the Scientific and Technological Support Project (Industry) of Jiangsu Province (No. BE2011195)the Major Program of the Natural Science Foundation of Institution of Higher Education of Jiangsu Province (No. 14KJA510001)
文摘In this paper, a generalized three-dimensional(3D) scattering channel model for macrocellular land mobile environments is considered. This model simultaneously describes angular arrival of multi-path signals in the azimuth and elevation planes in an environment where uniformly distributed scatterers are assumed to be present in hemispheroids around the base station(BS) and mobile station(MS). Using this channel model, we first derive the closed-form expression for the joint and marginal probability density functions of the angle-of-arrival and time-of-arrival measured at the BS and the MS corresponding to the azimuth and elevation angles. Next, we derive an expression for the Doppler spectral distribution caused by motion of the MSs. Furthermore, we analyze the performance of multiple-input multiple-output antenna systems numerically. The results show that the proposed 3D scattering channel model performs better than previously proposed two-dimensional(2D) models for indoor and outdoor environments. We compare the results with previous scattering channel models and measurement results to validate the generalizability of our model.
文摘This study analyzed the determinants of adoption of agricultural extension of Green River Project among rural households of Niger Delta, Nigeria. Questionnaire, which was randomly distributed, was used for data collection from 270 direct beneficiaries of the project. Frequency, percentage and multiple regression were used for data analyses. For the beneficiaries, the results indicated a mean age of 48 years, 9 years of formal education, annual net farm income of N115, 681.48 and 2.8 times of monthly contact with Project Extension Officers. The mean adoption status of the project was 56.6%. The relationship between socio-economic characteristics of beneficiaries and adoption status gave an R2 of 0.668. Age, education, farming, experience, farm income and extension contact were significant determinants of adoption. The study recommends improvement in formal education, farm income, extension contact and inclusion of younger farmers as beneficiaries to enhance adoption status.
基金Supported by YNSFC(10001026)for the first authorby Tianyuan Mathematics Foundation of NNSFCGuangxi Science Foundation and Guangxi Education Committee for the second author.
文摘Generalized Steiner triple systems, GS(2, 3, n, g) are equivalent to (g+1)-ary maximum constant weight codes (n, 3,3)s. In this paper, it is proved that the necessary conditions for the existence of a GS(2,3, n, 10), namely, n ≡ 0,1 (mod 3) and n ≥ 12, are also sufficient.
基金supported by the research grant under the Government of Malaysia
文摘In this article, we construct abundant exact traveling wave solutions involving free parameters to the generalized Bretherton equation via the improved (G′/G)-expansion method. The traveling wave solutions are presented in terms of the trigonometric, the hyperbolic, and rational functions. When the parameters take special values, the solitary waves are derived from the traveling waves.
基金supported by National Natural Science Foundation of China(Grant No.10971008)
文摘In this paper,a new version of the general form of the main inequality of Reich-Strebel is given.As applications,we improve the strong triangle inequality and generalize the Delta inequality in certain sense.
基金supported by National Natural Science Foundation of China (Grant No.11171140)the PAPD of Jiangsu Higher Education Institutions
文摘For integers b and c the generalized central trinomial coefficient Tn(b,c)denotes the coefficient of xnin the expansion of(x2+bx+c)n.Those Tn=Tn(1,1)(n=0,1,2,...)are the usual central trinomial coefficients,and Tn(3,2)coincides with the Delannoy number Dn=n k=0n k n+k k in combinatorics.We investigate congruences involving generalized central trinomial coefficients systematically.Here are some typical results:For each n=1,2,3,...,we have n-1k=0(2k+1)Tk(b,c)2(b2-4c)n-1-k≡0(mod n2)and in particular n2|n-1k=0(2k+1)D2k;if p is an odd prime then p-1k=0T2k≡-1p(mod p)and p-1k=0D2k≡2p(mod p),where(-)denotes the Legendre symbol.We also raise several conjectures some of which involve parameters in the representations of primes by certain binary quadratic forms.
基金supported by the National Natural Science Foundation for Distinguished Young Scholar(Grant No.50825901)the 111 Project(Grant No.B13024)+2 种基金the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT1125)the Project supported by the National Natural Science Foundation of China(Grant No.51379067)the Fundamental Research Funds for the Central Universities(Grant No.2011B14514)
文摘The particle breakage during specimen compaction had more significant influence on the position of the breakage critical-state line(BCSL)of Tacheng rockfill material(TRM)in the e-lnp’plane than the particle breakage during shearing,based on the large-scale triaxial compression tests on TRM in a wide range of densities and pressures.The state-dependent dilatancy and the plastic modulus were correlated to the breakage index,based on the formulations of the BCSL of TRM in the e-lnp’plane.The state-dependent model considering particle breakage was proposed for TRM within the framework of the generalized plasticity theory.The proposed model contained fourteen material constants.The test data of TRM from Group A were adopted to determine these material constants,while the test data from Group B were used independently to validate the model predictive capacity.The comparisons between model simulations and test data illustrated that the model with consideration of particle breakage could well represent the stress-strain behaviors of TRM,e.g.,the strain hardening and volumetric contraction behaviors at a loose state and the strain softening and volumetric expansion behaviors at a dense state,and also the particle breakage behaviors of TRM.
基金financially supported by the National Natural Science Foundation of China (Nos. 41001363 and 41471335)the Ocean Public Welfare Scientific Research Project, China (No. 201305021)
文摘Soil salinity is one of the most severe environmental problems worldwide. It is necessary to develop a soil-salinity-estimation model to project the spatial distribution of soil salinity. The aims of this study were to use remote sensed images and digital elevation model(DEM) to develop quantitative models for estimating soil salinity and to investigate the influence of vegetation on soil salinity estimation. Digital bands of Landsat Thematic Mapper(TM) images, vegetation indices, and terrain indices were selected as predictive variables for the estimation. The generalized additive model(GAM) was used to analyze the quantitative relationship between soil salt content, spectral properties, and terrain indices. Akaike's information criterion(AIC) was used to select relevant predictive variables for fitted GAMs. A correlation analysis and root mean square error between predicted and observed soil salt contents were used to validate the fitted GAMs. A high ratio of explained deviance suggests that an integrated approach using spectral and terrain indices with GAM was practical and efficient for estimating soil salinity. The performance of the fitted GAMs varied with changes in vegetation cover.Salinity in sparsely vegetated areas was estimated better than in densely vegetated areas. Visible red and near-infrared bands, and the second and third components of the tasseled cap transformation were the most important spectral variables for the estimation. Variable combinations in the fitted GAMs and their contribution varied with changes in vegetation cover. The contribution of terrain indices was smaller than that of spectral indices, possibly due to the low spatial resolution of DEM. This research may provide some beneficial references for regional soil salinity estimation.