Regularity of harmonic maps with the potential

The aim of this work is to prove the partial regularity of the harmonic maps with potential. The main difficulty caused by the potential is how to find the equation satisfied by the scaling function. Under the assumption on the potential we can obtain the equation, however, for a general potential, even if it is smooth, the partial regularity is still open.     

Decision-making in a Management Assessment Centre

Over the years, various methods and models for the assessment of management potential have been developed. A large financial institution uses an assessment centre to determine management potential of existing staff, and information collected from the various activities carried out at the centre is used to produce an overall rating of potential. The way in which this rating is determined is examined, and it is felt that a more effective method of using the information can be developed. In order to do this, a scientific approach to the analysis of the information already collected was adopted. From the results of the analysis, and with due consideration to the non-quantitative aspects of the situation, models for determining management potential can be developed.     

On absence of embedded eigenvalues for schrÖdinger operators with perturbed periodic potentials

The problem of absence of eigenvalues imbedded into the continuous spectrum is considered for a Schrödinger operator with a periodic potential perturbed by a sufficiently fast decaying "impurity" potential. Results of this type have previously been known for the one-dimensional case only. Absence of embedded eigenvalues is shown in dimensions two and three if the corresponding Fermi surface is irreducible modulo natural symmetries. It is conjectured that all periodic potentials satisfy this condition. Separable periodic potentials satisfy it, and hence in dimensions two and three Schrödinger operator with a separable periodic potential perturbed by a sufficiently fast decaying "impurity" potential has no embedded eigenvalues     

The design of reverse distribution networks: Models and solution procedures

Reverse distribution, or the management of product return flows, induced by various forms of reuse of products and materials, has received growing attention throughout this decade. In this paper we discuss reverse distribution, and propose a mathematical programming model for a version of this problem. Due to the complexity of the proposed model, we introduce a heuristic solution methodology for this problem. The solution methodology complements a heuristic concentration procedure, where sub-problems with reduced sets of decision variables are iteratively solved to optimality. Based on the solutions from the sub-problems, a final concentration set of potential facility sites is constructed, and this problem is solved to optimality. The potential facility sites are then expanded in a greedy fashion to obtain the final solution. This “heuristic expansion” was also performed using the solution found with a greedy heuristic to provide a short-list of potential facility sites. Computational tests demonstrate a great deal of promise for this solution method, as high-quality solutions are obtained while expending modest computational effort.     

A potential of fuzzy relations with a linear structure: The contractive case

In this paper we develop a potential theory of fuzzy relations on the positive orthant in a Euclidean space. By introducing a linear structure for fuzzy relations, the existence of a potential and its characterization by fuzzy relational equation are derived under the assumption of contraction and compactness. In the one-dimensional unimodal case, a potential is given explicity. Also, a numerical example is shown to illustrate our approaches.     

直立圆柱二阶波浪力解析解

大直径直立圆柱体上的二阶波浪力目前已有一些研究结果,但仍存在一些值得进一步探讨之处.这一方面在于二阶辐射条件还不甚清楚:另一方面在于已有的二阶力公式或是所含积分的收敛精度不易保证,或是表达式繁杂,不利于实际计算.本文在求解这一问题时,不是对二阶势提出辐射条件,而是对二阶势的周向富里叶分量提出辐射条件──Sommerfeld辐射条件.求解中,利用本文推导出的数学公式,简化了二阶自由面条件非齐次项的表达式,得到了形式简单,易于计算的二阶波浪力精确公式.二阶力计算结果与实验结果吻合良好.     

An accurate finite difference method for the numerical solution of the Schrödinger equation

An accurate finite difference approach for computing eigenvalues of Schrödinger equations is developed in this paper. We investigate two cases: (i) the specific case in which the potential V(x) is an even function with respect to x. It is assumed, also, that the wave functions tend to zero for x → ±∞. We investigate the well-known potential of the onedimensional anharmonic oscillator, the symmetric double-well potential, the Razavy potential and the doubly anharmonic oscillator potential. (ii) The general case for positive and negative eigenvalues and for the well-known cases of the Morse potential and Woods-Saxon or optical potential. Numerical and theoretical results show that this new approach is more efficient than previously derived methods.     

A GA-Simplex Hybrid Algorithm for Global Minimization of Molecular Potential Energy Functions

In this paper we propose a hybrid genetic algorithm for minimizing molecular potential energy functions. Experimental evidence shows that the global minimum of the potential energy of a molecule corresponds to its most stable conformation, which dictates its properties. The search for the global minimum of a potential energy function is very difficult since the number of local minima grows exponentially with molecule size. The proposed approach was successfully applied to two cases: (i) a simplified version of more general molecular potential energy functions in problems with up to 100 degrees of freedom, and (ii) a realistic potential energy function modeling two different molecules.     

Four-Parameter 1/<Emphasis Type="Italic">r</Emphasis><Superscript>2</Superscript> Singular Short-Range Potential with Rich Bound States and A Resonance Spectrum

We use the tridiagonal representation approach to enlarge the class of exactly solvable quantum systems. For this, we use a square-integrable basis in which the matrix representation of the wave operator is tridiagonal. In this case, the wave equation becomes a three-term recurrence relation for the expansion coefficients of the wave function with a solution in terms of orthogonal polynomials that is equivalent to a solution of the original problem. We obtain S-wave bound states for a new four-parameter potential with a 1/r² singularity but short-range, which has an elaborate configuration structure and rich spectral properties. A particle scattered by this potential must overcome a barrier and can then be trapped in the potential valley in a resonance or bound state. Using complex rotation, we demonstrate the rich spectral properties of the potential in the case of a nonzero angular momentum and show how this structure varies with the parameters of the potential.     

On the noncommutative Donaldson-Thomas invariants arising from brane tilings

Given a brane tiling, that is a bipartite graph on a torus, we can associate with it a quiver potential and a quiver potential algebra. Under certain consistency conditions on a brane tiling, we prove a formula for the Donaldson-Thomas type invariants of the moduli space of framed cyclic modules over the corresponding quiver potential algebra. We relate this formula with the counting of perfect matchings of the periodic plane tiling corresponding to the brane tiling. We prove that the same consistency conditions imply that the quiver potential algebra is a 3-Calabi-Yau algebra. We also formulate a rationality conjecture for the generating functions of the Donaldson-Thomas type invariants.     

A Duality Approach to Nonlinear Diffusion Equations

We provide new existence results for a nonlinear diffusion equation with a monotonically increasing multivalued time-dependent nonlinearity, under minimal growth and coercivity conditions. The results given in this paper prove that a generalized solution to the nonlinear equation is provided by a solution to an equivalent minimization problem for a convex functional involving the potential of the nonlinearity and its conjugate, in the case when the potential is time and space depending. If the potential is time depending only and it has a symmetry at infinity, the null minimizer in the minimization problem is found to coincide with a weak solution to the nonlinear equation.     

Nonlinear free surface condition due to second order diffraction by a pair of cylinders

An analysis of the non-homogeneous term involved in the free surface condition for second order wave diffraction on a pair of cylinders is presented. In the computations of the nonlinear loads on offshore structures the most challenging task is the computation of the free surface integral. The main contribution to this integrand is due to the nonhomogeneous term present in the free surface condition for second order scattered potential. In this paper, the free surface condition for the second order scattered potential is derived. Under the assumption of large spacing between the two cylinders, waves scattered by one cylinder may be replaced in the vicinity of the other cylinder by equivalent plane waves together with non-planner correction terms. Then solving a complex matrix equation, the first order scattered potential is derived and since the free surface term for second order scattered potential can be expressed in terms of the first order potentials, the free surface term can be obtained using the knowledge of first order potentials only.     

Piecewise homotopy analysis method and convergence analysis for formally well-posed initial value problems

In this paper, we apply the Schwarz waveform relaxation (SWR) method to the one-dimensional Schrödinger equation with a general linear or a nonlinear potential. We propose a new algorithm for the Schrödinger equation with time-independent linear potential, which is robust and scalable up to 500 subdomains. It reduces significantly computation time compared with the classical algorithms. Concerning the case of time-dependent linear potential or the nonlinear potential, we use a preprocessed linear operator for the zero potential case as a preconditioner which leads to a preconditioned algorithm. This ensures high scalability. In addition, some newly constructed absorbing boundary conditions are used as the transmission conditions and compared numerically.     

The least square values and the shapley value for cooperative TU games

The main result proved in this paper is the fact that any Least Square Value is the Shapley value of a game obtained from the given game by rescaling. An Average per capita formula for Least Square Values, similar to the formula for the Shapley value (Dragan (1992)), will lead to this conclusion and allow a parallel computation for these values. The potential for the Least Square Values, a potential basis relative to Least Square Values and an approach similar to the one used for the Shapley value is allowing us to solve the Inverse problem for Least Square Values.     

Directional fields algebraic non-linear solution equations for mobile robot planning

In this study, a novel approach to robot navigation/planning by using half-cell electrochemical potentials is presented. The half-cell electrode’s potential is modelled by the Nernst equation to yield automatic search/detection of pipeline flaws by using the direct current voltage gradient (DCVG) technique. We introduce a theory of spherical volumetric electric density in the soil to sustain our postulates for navigational potential fields. The Nernst potential is correlated with the distance to a pipe’s flaw by proposing a fitted theoretical-empirical nonlinear regression model. From this, volumetric derivatives are solved as gradient-based fields to control wheeled robot’s motion. A nonlinear system for trajectory planning is proposed, and analytically solved by an algebraic solution. This solution directly adjust robot’s speed kinematic values to lead it toward the flaw. The inverse/forward kinematic constraints are non-holonomic, and are recursively integrated into the general potential equation. Analytical modelling is reported, and a set of numerical simulations are presented to prove the feasibility of the proposed formulations.     

Distribution of a liquid and the effective potential in a bounded system with special geometry

We evaluate the density of the distribution of a liquid bounded by a system of coaxial cylinders with a fixed near-wall potential. The problem is solved in the smooth-inhomogeneity approximation for a near-wall potential of arbitrary type. Based on the obtained solution, we analyze the special case where the near-wall potential is essentially short range and remains constant inside each of the sublayers in its range of action. In this case, we evaluate the effective near-wall potential for which the density distribution is a continuous function in the entire domain.     

Dynamic effect of Bloch electrons in time-periodic electric fields

The dynamic effect of Bloch electrons under the action of temporally periodic electric fields is studied. The explicit solutions for the quasienergies and the Floquet states are obtained exactly and generally, from which the localized or extended nature of Floquet states is demonstrated to be controlled by a reduced vector potential in one period of electric fields. When this reduced vector potential is an irrational, all the Floquet states are localized except the cases where the reduced vector potential is extremely well approximated by rationals (i.e., a Liouville number) and simultaneously the instersite hopping does not decay fast enough, for which the Floquet states are found to be more and more extended at large distances. When this reduced vector potential approaches an ordinary rational, all the Floquet states are extended. However, if the reduced vector potential has typical Diophantine properties, and if the intersite hopping decreases fast enough, the Floquet states cannot be extended. Project supported in part by the National Natural Science Foundation of China and the Chinese Academy of Engineering and Physics.     

The Structure of Minimizers of the Frame Potential on Fusion Frames

In this paper we study the fusion frame potential that is a generalization of the Benedetto-Fickus (vectorial) frame potential to the finite-dimensional fusion frame setting. We study the structure of local and global minimizers of this potential, when restricted to suitable sets of fusion frames. These minimizers are related to tight fusion frames as in the classical vector frame case. Still, tight fusion frames are not as frequent as tight frames; indeed we show that there are choices of parameters involved in fusion frames for which no tight fusion frame can exist. We exhibit necessary and sufficient conditions for the existence of tight fusion frames with prescribed parameters, involving the so-called Horn-Klyachko’s compatibility inequalities. The second part of the work is devoted to the study of the minimization of the fusion frame potential on a fixed sequence of subspaces, with a varying sequence of weights. We related this problem to the index of the Hadamard product by positive matrices and use it to give different characterizations of these minima.     

On a thermal stress problem for contacting half-spaces with inclusions of other material involving a new method for computing potentials and singular integrals

This paper deals with a thermal stress problem for contacting half-spaces of different materials having an inclusion of other material. With the aid of the contact tensor of two half spaces the problem is reduced to singular integral equations. Some new theorems on potentials with the contact tensor are used. Finally, a potential of the double layer with the contact tensor in the kernel and a singular integral operator, being the direct value of the potential, are calculated. For this a Kupradze method is applied, interpreting this potential as a solution of a contact problem of elastostatics. Some numerical experiments are communicated.     

A modified homogeneous potential reduction algorithm for solving the monotone semidefinite linear complementarity problem

In this paper, we study the performance of the Semidefinite Linear Complementarity Problem (SDLCP) for symmetric matrices that is equipped with a continuously differentiable potential function. A practical homogeneous self-dual potential reduction algorithm based on this potential function is prescribed, and we establish a computational basis for interior point methods with the use of HKM directions towards the central trajectory for the monotone SDLCP. Our computational implementation maintains a global linear polynomial time convergence, while achieving strong practical performance in comparison with existing solution methods.