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Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity (CK), farmer practice (FP), high yield and high efficiency (HH), and super high yield (SH), to estimate the yield gap. Different factorial experiments (fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha–1, respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors (contribution rates) were plant density (13.29%)>fertilizer (11.95%)>hybrids (8.19%)>irrigation (4%) for FP to HH, and hybrids (8.94%)>plant density (4.84%)>fertilizer (1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.

The nonlocal nonlinear boundary value problem with turning point is considered. Leading the stretched variables the formal asymptotic solution of the original problem is constructed. And by using the theory of differential inequalities the existence and uniformly validity of solution for the original boundary value problems are proved. The contribution of this paper is that, the asymptotic behavior of solution is studied by using a simple and special method.

Circular features are one of the most widely used shapes for camera calibration, due to several advantages: easy to make and recognize, not sensitive to image noise, symmetry, analytic formulation is simple. However, perspective projection is generally not a shape preserving transformation. A circle often mapped as an ellipse on the image plane when the feature and the image plane are not parallel to each other, as a result, the center of the circle shift from the center of the ellipse. In this paper we present a simple and robust algorithm to compensate this bias before camera calibration. Experimental results show the algorithm is important and convenient.

The impacts of initial perturbations on the computational stability of nonlinear evolution equations for non-conservative difference schemes and non-periodic boundary conditions are studied through theoretical analysis and numerical experiments for the case of onedimensional equations. The sensitivity of the difference scheme to initial values is further analyzed. The results show that the computational stability primarily depends on the form of the initial values if the difference scheme and boundary conditions are determined. Thus, the computational stability is sensitive to the initial perturbations.

This paper presents a stable least squares ellipses fitting algorithm based on Zernike orthogonal moments. The algorithm uses Zernike orthogonal moments for sub-pixel edge detection, and a mask of seven multiply seven was derived in the meantime. The optimal ellipse parameters were computed according to the data points extracted previously. This stable, robust and non-iterative algorithm can be easily implemented. The experiment results show that the proposed algorithm is effective in various situations.

This paper consider a class of perturbed mechanism for the western boundary undercurrents in the Pacific. The model of generalized governing equations is studied. Using the perturbation method, it constructs the asymptotic solution of the model. And the accuracy of asymptotic solution is proved by the theory of differential inequalities. Thus the uniformly valid asymptotic expansions of the solution are obtained.

A class of nonlinear coupled system for E1 Niňo-southern Oscillation (ENSO) model is considered. Using the asymptotic theory and method of variational iteration, the asymptotic expansion of the solution for ENSO models is obtained.

This paper introduced present application in the world and some problems in the calibration technique of 3D measuring system. Auto-calibration technique of multiple targets tracking for detecting outline based on random placement and regular number is put forward. At the same time, the concrete algorithm is given. Then, according to the algorithm, the corresponding experimental result is obtained. Furthermore, the calibration accuracy is compared and analyzed. Finally, it comes to a conclusion that this algorithm can make the operation more simple and convenient. And the calibration accuracy is kept within 0.03mm.

In this paper the singularly perturbed initial boundary value problems for the nonlocal reaction diffusion system are considered. Using the iteration method and the comparison theorem, the existence and its asymptotic behavior of the solution for the problem are studied.

A class of coupled system for the El Nino–Southern Oscillation (ENSO) mechanism is studied. Using the method of variational iteration for perturbation theory, the asymptotic expansions of the solution for ENSO model are obtained and the asymptotic behaviour of solution for corresponding problem is considered.

The singularly perturbed boundary value problem for the nonlinear boundary conditions is considered. Under suitable conditions, the asymptotic behavior of solution for the original problems is studied by using theory of differential inequalities.

A nonlinear singularly perturbed problems for reaction diffusion equation with boundary perturbation is considered. Under suitable conditions, the asymptotic behavior of solution for the initial boundary value problems of reaction diffusion equations is studied using the theory of differential inequalities.

A class of initial boundary value problems for the reaction diffusion equations are considered. The asymptotic behavior of solution for the problem is obtained using the theory of differential inequality.

The singularly perturbed initial value problem for a nonlinear singular equation is considered. By using a simple and special method the asymptotic behavior of solution is studied.

For the nonconservative schemes of the nonlinear evolution equations, taking the one-dimensional shallow water wave equation as an example, the necessary conditions of computational stability are given. Based on numerical tests, the relationship between the nonlinear computational stability and the construction of difference schemes, as well as the form of initial values, is further discussed. It is proved through both theoretical analysis and numerical tests that if the construction of difference schemes is definite, the computational stability of nonconservative schemes is decided by the form of initial values.

For the conservative and non-conservative schemes of nonlinear evolution equations, by taking the two-dimensional shallow water wave equations as an example, a comparative analysis on computational stability is carried out. The relationship between the nonlinear computational stability, the structure of the difference schemes, and the form of initial values is also discussed.

For several difference schemes of linear and non-linear evolution equations, taking the one-dimensional linear and non-linear advection equations as examples, a comparative analysis for computational stability is carried out and the relationship between non-linear computational stability, the construction of difference schemes, and the form of initial values is discussed. It is proved through comparative analysis and numerical experiment that the computational stability of the difference schemes of the non-linear evolution equation are absolutely different from that of the linear evolution equation.

In this paper, we consider a more general form of weak vector variational inequalities and prove some results on the existence of solutions of our new class of weak vector variational inequalities in the setting of Hausdorff topological vector topological space. We also discuss the connectedness of a solution set to some vector variational inequalities, and obtain a useful sufficient condition.

Based on the forced dissipative nonlinear evolution equations for describing the motion of atmosphere and ocean, the computational stability of the explicit difference schemes of the forced dissipative nonlinear atmospheric and oceanic equations is analyzed and the computationally stable explicit complete square con-servative difference schemes are constructed. The theoretical analysis and numerical experiment prove that the explicit complete square conservative difference schemes are computationally stable and deserve to be disseminated.

The computational stability of the explicit difference schemes of the forced dissipative nonlinear evolution equations is analyzed and the computational quasi-stability criterion of explicit difference schemes of the forced dissipative nonlinear atmospheric equations is obtained on account of the concept of computational quasi-stability, Therefore, it provides the new train of thought and theoretical basis for designing computational stable difference scheme of the forced dissipative nonlinear atmospheric equations.

Some problems of nonlinear computational instability are discussed in this article, which are shown as follows: 1) Three types of representative evolution equations are analyzed, and the close relationship between the nonlinear computational stability or instability in their corresponding difference equations and the properties of their solution is revealed. 2) The problem of nonlinear computational instability in conservative differencing equations with the periodic boundary condition is further discussed, and some effective ways to avoid nonlinear computational instability are proposed. 3) The problem of nonlinear computational instability in non-conservative difference equations with the aperiodic boundary condition is focused on by using nonlinear advection equations as examples, and “synthetic analysis method” is given to judge their computational stability.

A time delay equation for sea-air oscillator model is studied. The aim is to create an asymptotic soling method of nonlinear equation for the ENSO model. And based on a class of oscillators of ENSO model, employing the variational iteration method, the approximate solution of corresponding problem is obtained. It is proven from the results that the method of variational iteration method can be used for analyzing the sea surface temperature anomaly in the equatorial eastern Pacific of the atmosphere-ocean oscillation for ENSO model. *Supported by National Natural Science Foundation of China (Grant Nos. 40576012, 90111011), the National Program on Key Basic Research Project (Grant No. 2004CB418304) and in part by E-Institute of Shangai Municipal Education Commission (Grant No. E03004)

Recently, CAO et al. proposed an efficient electronic voting scheme based on the polynomial function. They claimed to satisfy the fairness, uniqueness, eligibility, anonymous, accuracy and robustness. In this paper, we show that the electronic voting can guarantee neither robustness nor anonymity. Some candidate can add the ballot number by altering data, and any candidate can know the accurate content of each vote after the tallying stage.

This paper deals with the vector equilibrium problem. The concept of super efficiency for vector equilibrium is introduced. A scalar characterization of super efficient solution for vector equilibrium is given. By using of the scalarization result, we discuss the connectedness of super efficient solutions set to the vector equilibrium problems in locally convex topological vector spaces.

The approximate solitary-like wave solution for a class of disturbed evolution equation is considered using a simple and valid technique. First, an approximate solution of a corresponding typical differential equation is introduced, and then the approximate solution for an original disturbed evolution equation is obtained using the functional mapping method. It is pointed out that the series of approximate solution is convergent. The accuracy of the approximate solution is also discussed using the analytic method.

A class of disturbed evolution equation is considered using a simple and valid technique. We first introduce the periodic traveling-wave solution of a corresponding typical evolution equation. Then the approximate solution for an original disturbed evolution equation is obtained using the asymptotic method. We point out that the series of approximate solution is convergent and the accuracy of the asymptotic solution is studied using the fixed point theorem for the functional analysis.

A solving problem for the Lorenz system in atmospheric physics is considered. First, a set of variational iterations is constructed by using the generalized variation principle. Then, the initial approximate solution is determined. Finally, using the variational iteration, each approximate solution for corresponding model is found. The generalized variational iteration method is an analytic method, and the obtained solution can be analytically operated further.

A box model of the interhemispheric thermohaline circulation in the disturbed sea-air for globe climate is considered. By using the homotopic mapping method，a class of nonlinear model is studied, and the approximate solution is obtained. The homotopic mapping solving method is an analytic method，the solution obtained can be analytically operated sequentially. And then we can also study the diversified qualitative and quantitative behaviors of corresponding physical quantities.

An equation for the equatoral Kelvin wave is considered. By using the variational iteration method, the approximate solution is studied. The variational iteration method is an analytic method, the obtained solution can be analytic operation sequentially.

The model for gain fluence of a laser pulse amplifier is studied. Firstly, using the generalized variational iteration method, the Lagrange multipicator is determined. Then the iteration expansions are constructed. Thus approximate solutions for the corresponding model are obtained.

The problem of solving the Lorenz equation is considered. Firstly，a set of homotopic mapping is constructed. Then the initial approximate solution is determined. Finally，using the homotopic mapping，the approximation for corresponding model is found. The homotopic mapping method is an analytic method，the obtained solution can be used in analytic operations subsequently.

A three dimentional equation for the equatoral sea-air oscillator Kelvin wave is considered. By using the variational iteration method，the approximate solution of the corresponding model is studied. The variational iteration method is an analytic method，the obtained solution can be used in further analytical operations.

In this paper, a class of wading wave equations are considered. Using the homotopic mapping theory and method, the corresponding approximate solution of the system is obtained.

A time delay equation for sea-air oscillator model is studied. We aim at the cre ateion of an approximate method for solving sea-air oscillator model of nonlinea r equation, employing the theory of homotopic mapping, with due colisideration o f the approximate solution of the corresponding problem. This is an approximate analytical method, which can be further used for analyzing other behaviors of th e sea surface temperature anomaly of the atmosphere-ocean oscillator model.

Atmospheric physics deals with very complicated natural phenomena. Basic models have to be implemented for the sea-air and land-air oscillators and then solve them using the approximate method. In this paper, a class of nonlinear coupling system for land-air oscillator model is studied. Using the homotopic mapping method, it is translated into solving linear problems, and the approximate expressions for the original nonlinear problem are obtained.

A sea-air oscillator model of the nonlinear coupling system is studied.Using the variational iteration principle,a series of corresponding functional is constructed.Then the Lagrange operators are selected.Finally,using the generalized variational iteration method,the approximate sequences of a series of solutions for the sea-air oscillator model are obtained.

A class of coupled systems in oscillation of the El Nio-Southern Oscillation (ENSO) mechanism has been studied. Using the homotopic mapping and perturbed theory, approximate expansions of the solution for a class of ENSO model are obtained in a simple manner.

The El Nio atmospheric physics mechanism is studied. Using the variational iteration theory, the approximation of the solution for its model is obtained for shortcut calculation. And compared to the special case for the exact solution of the model, the first approximate solution from the variational iteration method is in excellent agreement with the exact solution in degree of accuracy.

The oscillation for a class of coupled systems in the El Nio-Southern Oscillatio n (ENSO) mechanism is studied. Using the perturbation theory and perturbative me thod, the uniformly valid asymptotic expansions of the solution for a class of E NSO model are obtained easily.

A delayed oscillator of El NiňoSouthern Oscillation (ENSO) models are conside red. Using the method of homotopic mapping, the approximation of the solution for ENSO models is obtained.