Types Of Potential Functions Research Articles

A game-theoretic approach to managing the composition and structure of a bearing-only measurement system in conditions of a priori uncertainty

The problem of managing the composition and structure of a bearing-only measurements system (BOMS) in a game-theoretic formulation is considered. An approach of cooperative search for the placement of BOMS points and a method for estimating the work-time indicator of the system are proposed. The search for the placement of BOMS points uses the toolkit of multi-agent potential games. The criteria for selecting the placement of points and the type of potential function are determined. The management of the composition and structure of the BOMS is based on the results of the cluster-variation method. A structural and functional description of the simulation model is presented. The above results of simulation modeling confirm the practical effectiveness of the proposed approaches.

Duffin–Kemmer–Petiau oscillator in the presence of a cosmic screw dislocation

We examine the behavior of spin-zero bosons in an elastic medium which possesses a screw dislocation, which is a type of topological defect. Therefore, we solve analytically the Duffin–Kemmer–Petiau (DKP) oscillator for bosons in the presence of a screw dislocation with two types of potential functions: Cornell and linear-plus-cubic potential functions. For each of these functions, we analyze the impact of screw dislocations by determining the wave functions and the energy eigenvalues with the help of the Nikiforov–Uvarov method and Heun function.

A Vector Potential Function-Based Collision Avoidance Control for Differential-Steered Robots

A collision avoidance control that tracks a vector potential field-based velocity plan of a differential-steered robot is designed. Vector potential function (VPF) is a type of potential function used for motion planning. The plan resulted by the VPF is the desired velocity vector of the robot on all points in collision-free space. The problem to address in this paper is velocity tracking control in the environment of a circular obstacle. A controller is designed to track the VPF-based velocity plan. A concept of collision cone will be used to evaluate the ability of the controller to avoid collision between the robot and the obstacle. The stability of the controller is verified by using the Lyapunov stability analysis. Simulations of the controller’s performance are presented.

Extended photoacoustic transport model for characterization of red blood cell morphology in microchannel flow.

The dynamic response behavior of red blood cells holds the key to understanding red blood cell related diseases. In this regard, an understanding of the physiological functions of erythrocytes is significant before focusing on red blood cell aggregation in the microcirculatory system. In this work, we present a theoretical model for a photoacoustic signal that occurs when deformed red blood cells pass through a microfluidic channel. Using a Green's function approach, the photoacoustic pressure wave is obtained analytically by solving a combined Navier-Stokes and photoacoustic equation system. The photoacoustic wave expression includes determinant parameters for the cell deformability such as plasma viscosity, density, and red blood cell aggregation, as well as involving laser parameters such as beamwidth, pulse duration, and repetition rate. The effects of aggregation on blood rheology are also investigated. The results presented by this study show good agreements with the experimental ones in the literature. The comprehensive analytical solution of the extended photoacoustic transport model including a modified Morse type potential function sheds light on the dynamics of aggregate formation and demonstrates that the profile of a photoacoustic pressure wave has the potential for detecting and characterizing red blood cell aggregation.

A note on the uniqueness of 2D elastostatic problems formulated by different types of potential functions

Abstract New additional conditions required for the uniqueness of the 2D elastostatic problems formulated in terms of potential functions for the derived Papkovich-Neuber representations, are studied. Two cases are considered, each of them formulated by the scalar potential function plus one of the rectangular non-zero components of the vector potential function. For these formulations, in addition to the original (physical) boundary conditions, two new additional conditions are required. In addition, for the complete Papkovich-Neuber formulation, expressed by the scalar potential plus two components of the vector potential, the additional conditions established previously for the three-dimensional case in z-convex domain can be applied. To show the usefulness of these new conditions in a numerical scheme two applications are numerically solved by the network method for the three cases of potential formulations.

Revisiting Deep Structured Models for Pixel-Level Labeling with Gradient-Based Inference

Semantic segmentation and other pixel-level labeling tasks have made significant progress recently due to the deep learning paradigm. Many state-of-the-art structured prediction methods also include a random field model with a hand-crafted Gaussian potential to model spatial priors and label consistencies and feature-based image conditioning. These random field models with image conditioning typically require computationally demanding filtering techniques during inference. In this paper, we present a new inference and learning framework which can learn arbitrary pairwise conditional random field (CRF) potentials. Both standard spatial and high-dimensional bilateral kernels are considered. In addition, we introduce a new type of potential function which is image-dependent like the bilateral kernel, but an order of magnitude faster to compute since only spatial convolutions are employed. It is empirically demonstrated that such learned potentials can improve segmentation accuracy and that certain label-class interactions are indeed better modeled by a non-Gaussian potential. Our framework is evaluated on several public benchmarks for semantic segmentation with improved performance compared to previous state-of-the-art CNN+CRF models.

A concrete damage–plasticity model for FRP confined columns

Proper design of fibre reinforced polymer (FRP) retrofitted concrete columns requires an appropriate concrete model that describes both confinement sensitivity (i.e increase of the strength and ductility) and dilation characteristic of concrete under the triaxial stress state. In this paper, a confinementsensitive damage plasticity model for concrete material is developed. The dilation behaviour is predicted using a non associated Cam-Clay type potential function. The application of the model is demonstrated in the case of actively and FRP confined (passive) concrete. It is found that essential mechanical features of the confined concrete can be reproductrice for both actively and passively confined concrete in practical engineering uses.

Editorial: Quantum Structures in Cognitive and Social Science.

Editorial: Quantum Structures in Cognitive and Social Science.

Accelerating Airy beams in the presence of inhomogeneities

Studies have already been made of accelerating Airy beams in the presence of deterministic inhomogeneities, illustrating, in particular, that the inherent self-healing properties of such beams are preserved. The cases of a range-dependent linear transverse potential and a converging GRIN structure (harmonic oscillator) have been examined thoroughly. Examples will be given in this article of novel accelerating Airy beams in the presence of five other types of potential functions. Three of the resulting exact analytical solutions have a common salient characteristic property: they are constructed using the free-space accelerating Airy beam solution as a seed.

Two types of potential functions and their use in the modeling of information: two applications from the social sciences.

In this paper we consider how two types of potential functions, the real and quantum potential can be shown to be of use in a social science context. The real potential function is a key ingredient in the Hamiltonian framework used in both classical and quantum mechanics. The quantum potential however emerges in a different way in quantum mechanics. In this paper we consider both potentials and we attempt to give them a social science interpretation within the setting of two applications.

Predication of Thermal Conductivity of Mg2X (X = Ge and Sn) by Molecular Dynamics

Molecular dynamics (MD) simulations of elastic and thermal properties of Mg2X (X = Ge and Sn) based on anti-fluorite structure (CaF2) at temperature range 300−700 K were presented. The MD simulation in this study involving the Morse−type potential functions, and the Busing–Ida potential to determine the interatomic interaction among cluster atoms size 4×4×4 unit cells of 768 atoms {512−Mg1.2+, 256−(Ge, Sn)2.4−}. The potential parameter functions of the cluster atoms were indicated by random numerical method and fit lattice parameter from the experimental data obtained at room temperature. The calculation of lattice parameter, pressure, temperature and energy contributes to evaluation of the elastic properties. The results showed that Mg2Ge had better elasticity than Mg2Sn. On the other hand, Mg2Sn had less thermal conductivity than Mg2Ge. Since thermal conductivity decreases with increasing temperature, the interesting feature of thermal conductivity is particulary useful to enhance thermoelectric performance of materials.

Potential Functions and the Characterization of Economics-Based Information

The formulation of quantum mechanics as a diffusion process by Nelson (Phys Rev 150:1079–1085, 1966) provides for an interesting approach on how we may transit from classical mechanics into quantum mechanics. Besides the presence of the real potential function, another type of potential function (often denoted as ‘quantum potential’) forms an intrinsic part of this theory. In this paper we attempt to show how both types of potential functions can have a use in a resolutely macroscopic context like financial asset pricing. We are particularly interested in uncovering how the ‘quantum potential’ can add to the economics-based relevant information which is already supplied by the real potential function.

Finite Element Model to Simulate Crack Propagation Using Interface Elements and Its Verification in Tensile Test

Since the crack generation and its propagation caused by welding defects is one of the main hull damage patterns, the simulation of crack propagation process has an important significance for ship safety. Based on interface element method, a finite element model to simulate crack propagation is studied in the paper. A Lennard-Jones type potential function is employed to define potential energy of the interface element. Tensile tests of steel flat plates with initial central crack are carried out. Surface energy density and spring critical stress that are suitable for the simulation of crack propagation are determined by comparing numerical calculation and tests results. Based on a large number of simulation results, the curve of simulation correction parameter plotted against the crack length is calculated.

Thermal expansion and thermal conductivity of (Th,Ce)O2 mixed oxides: A molecular dynamics and experimental study

Thermal expansion and thermal conductivity of ThO2 and (Th,Ce)O2 mixed oxides (MOX) have been investigated by using molecular dynamics (MD) simulation and experimental study. The MD simulations have been performed on ThO2, CeO2 and (Th,Ce)O2 using Coulomb–Buckingham type potential function with partial ionic charges. The interatomic potentials of ThO2 and CeO2 are derived in this study and special quasirandom structures are employed to establish solid solution configurations. In order to evaluate the effect of inhomogeneous distribution of CeO2 in ThO2 matrix and change in oxygen to metal ratio (O/M) on thermal properties of MOX, the samples of (Th,Ce)O2 were prepared by conventional powder metallurgy route as well as coated agglomerate pelletization (CAP) route and sintered in air as well as Ar–H2 atmospheres. The thermal expansions of ThO2 and (Th,Ce)O2 (3, 5 and 8wt% CeO2) are measured using dilatometry and thermal diffusivities of ThO2 and ThO2–5wt% CeO2 were measured using a laser flash technique. The experimental results of thermal properties of (Th,Ce)O2 showed good correlation with those of MD simulations. It was found that the effect of inhomogeneity on thermal expansion and conductivity was not very significant, while porosity as well as O/M (stoichiometry) of the pellet majorly affected thermal properties.

Fourier type potential energy function for conformational change of selected organic functional groups

The energy changes associated with internal rotation of a functional group in a molecule depend on the topology of the chemical environment. Energies obtained from electron structure and force-field calculations have been analyzed by Fourier expansions. The findings show that rotation around bonds connecting atoms without lone pairs can be described with a one term Fourier-series. In contrast, two or three terms are needed if the connected atoms have lone pairs. The analysis inspires adoption of a simplified Fourier expansion that reproduces the data well, suggesting that Fourier-type-series with few terms are useful in describing any internal rotation analytically.

A fluid-particle interaction method for blood flow with special emphasis on red blood cell aggregation

This paper presents a fluid-particle interaction algorithm using the distributed Lagrange multiplier based fictitious domain method. The application of this method to the numerical investigation of motion and aggregation of red blood cells in two-dimensional microvessels is discussed. The cells are modelled as rigid biconcave-shaped neutrally buoyant particles. The aggregating force between two cells is derived from a Morse type potential function. The cell-cell interaction is coupled with the fluid-cell interaction through a time splitting scheme. Simulation results of multiple red blood cells in Poiseuille flow are presented. Because of its modular nature, this algorithm is applicable to a large class of problems involving the processes of particle aggregation and fluid-particle interaction.

Knowledge-based potentials in protein fold recognition

An accurate potential function is essential for protein folding problem and structure prediction. Two different types of potential energy functions are currently in use. The first type is based on the law of physics and second type is referred to as statistical potentials or knowledge based potentials. In the latter type, the energy function is extracted from statistical analysis of experimental data of known protein structures. By increasing the amount of three dimensional protein structures, this approach is growing rapidly. There are various forms of knowledge based potentials depending on how statistics are calculated and how proteins are modeled. In this review, we explain how the knowledge based potentials are extracted by using known protein structures and briefly compare many of the potentials in theory.

Bond-order potential for transition metal carbide cluster for the growth simulation of a single-walled carbon nanotube

A classical many-body potential for transition metal carbide cluster is developed in the form of the bond-order type potential function. The parameter sets between carbon atoms and several transition metal atoms (Fe, Co and Ni) are constructed by fitting binding energies from Density Functional Theory (DFT) calculations. Using the potential function, clustering process of carbon atoms to a small metal cluster is studied by classical molecular dynamics (MD) simulation. The number of hexagonal rings in the Co cluster increases about twice as fast as in the Fe cluster. This implies that the graphitic lattice interacts more strongly with Co atoms than with Fe atoms. A Co cluster has a crystal structure where metal atoms are regularly allocated and embedded in the hexagonal carbon network in the simulation. In contrast, carbon atoms cover the entire surface in case of the Fe cluster. Additionally, the potential energy surface that a carbon atom feels from a 2D closed-packed facet is examined using a hypothetical FCC(111) facet of several transition metals. The potential energy minima are distributed on the hexagonal network showing the 2D closed-packed facet can be a template where a graphene is formed.

Development of a bond-order type interatomic potential for Si–B systems

A bond-order type interatomic potential for Si–B systems is developed. We employed the bond-order type potential function proposed by Tersoff. Properties of Si–B crystals which involve a wide range of local atomic environments are used for fitting. The formation energies of various atomic structures that are thought to appear during B diffusion or Si–B clustering are also fitted. A genetic algorithm is used to find the optimized parameters. The resulting potential reproduced well the Si-interstitial-assisted diffusion of B as well as the physical properties used for fitting.

Thermodynamic Properties of Multicomponent Liquid Mixtures

Considering a ternary liquid mixture to be made up of three binary mixtures, by means of cell model using Sutherland type potential function for pair interaction between molecules, a statistical theory for binary liquid mixtures has been extended for ternary systems. In the light of above extension, excess volume ( V E ), excess energy ( E E ) and excess entropy ( TS E ) have been computed for three binary (benzene + cyclohexane, benzene + chlorobenzene and cyclohexane + chlorobenzene) and the resultant ternary system (benzene + cyclohexane + chlorobenzene) at 298.15 K. All the above mentioned excess properties have been computed from the data of ultrasonic velocity and density only.