Citation: Lyu J, Song J, Liu Y, Wang Y, Li J and Du FK (2018) Species Boundaries Between Three Sympatric Oak Species: Quercus aliena, Q. dentata, and Q. variabilis at the Northern Edge of Their Distribution in China. Front. Plant Sci. 9:414. doi: 10.3389/fpls.2018.00414 Species Boundaries Between Three Sympatric Oak Species: Quercus aliena, Q. dentata, and Q. variabilis at the Northern Edge of ...

Article history: Received 1 December 2011 Received in revised form 13 April 2013 Accepted 16 April 2013 Available online 20 May 2013 We designed and implemented a novel omnidirectional spherical robot. Instead of using wheels or flywheels, a driven ball is installed inside the spherical shell and driven by two orthogonally-mounted rollers; thus, the omnidirectional mobility of the robot with no...

We consider deterministic and disordered frustrated systems in which we can show some strict inequalities with respect to related ferromagnetic systems. A case particularly interesting is the Edwards-Anderson spin-glass model in which it is possible to determine a region of uniqueness of the Gibbs measure, which is strictly larger than the region of uniqueness for the related ferromagnetic syst...

The inverse kinematics problem for redundant manipulators is ill-posed and nonlinear. There are two fundamentally different issues which result in the need for some form of regularization; the existence of multiple solution branches (global ill-posedness) and the existence of excess degrees of freedom (local illposedness). For certain classes of manipulators, learning methods applied to input-o...

We discuss a new cluster representation for the internal energy and the specific heat of the d-dimensional Ising model , obtained by studying the percolation mapping of an Ising model with an arbitrary set of antiferromagnetic links. Such a representation relates the thermal operators to the topological properties of the Fortuin-Kasteleyn clusters of Ising percolation and is a powerful tool to ...

This paper presents a solution scheme for forward kinematics of a general fully parallel manipulator that guarantees a unique solution with only three redundant sensors. The redundant sensors were designed to minimize engineering difficulties in the realization, whereas an optimal sensor location was proposed to achieve a numerical efficiency and accuracy significantly better than existing solu...

This paper describes several methods for evaluation of kinematic parameters of a Stewart platform. One of those methods is the calculation of workspace area both in numerical and graphical form. The second method allows us to analyze and estimate inherent mechanism errors that occur due to actuator errors, elastic and thermal deformations and other error sources. Furthermore, another procedure ...

The Lagrangian approach to the development of dynamics equations for a multi-body system, constrained or otherwise, requires solving the forWard kinematics of the system at velocity level in order to derive the kinetic energy of the system. The kinetic-energy expression should then be differentiated multiple times to derive the equations of motion of the system. Among these differentiations, th...

A class of analytic planar 3-RPR manipulators is analyzed in this paper. These manipulators have congruent base and moving platforms and the moving platform is rotated of 180 deg about an axis in the plane. The forward kinematics is reduced to the solution of a 3-degree polynomial and a quadratic equation in sequence. The singularities are calculated and plotted in the joint space. The second-o...