in this paper, the time-like hyperruled surfaces in the minkowski 4-space and their algebraicinvariants are worked. also some characteristic results are found about these algebraic invariants.

Incremental dynamic analysis (IDA) requires the analysis of the non-linear response history of a structure for an ensemble of ground motions, each scaled to multiple levels of intensity and selected to cover the entire range of structural response. Recognizing that IDA of practical structures is computationally demanding, an approximate procedure based on the reduction of the number of ground m...

This article concerned on the study of signature submanifolds for curves under Lie group actions SE(2), SA(2) and for surfaces under SE(3). Signature submanifold is a regular submanifold which its coordinate components are differential invariants of an associated manifold under Lie group action, and therefore signature submanifold is a key for solving equivalence problems.

the main objective of this article is to optimize the walking pattern of a 2d humanoid robot with heel-off and toe-off motions in order to minimize the energy consumption and maximize the stability margin. to this end, at first, a gait planning method is introduced based on the ankle and hip joint position trajectories. then, using these trajectories and the inverse kinematics, the position tra...

Charged particles in a magnetosphere are spontaneously attracted to a planet while increasing their kinetic energy via inward diffusion process. A constraint on particles’ micro-scale adiabatic invariants restricts the class of motions available to the system, giving rise to a proper frame on which particle diffusion occurs. We investigate the inward diffusion process by numerical simulation of...

The main objective of this article is to optimize the walking pattern of a 2D humanoid robot with heel-off and toe-off motions in order to minimize the energy consumption and maximize the stability margin. To this end, at first, a gait planning method is introduced based on the ankle and hip joint position trajectories. Then, using these trajectories and the inverse kinematics, the position tra...

In this paper, for one-parameter closed dual spherical motions, we define the dual versions of the area vector of a given closed space curve, and the area projection of this curve in the direction of a given unit vector. The relationship between the above dual versions and the dual Steiner vector of the motion is used to give a generalization for Holditch’s theorem of planar kinematics into spa...

Euler equations for rotationally symmetrical motions of ideal fluid are considered. Basis of differential invariants for infinite-dimensional part of admitted group is calculated. The basis is used for construction of group foliation of Euler equations. Both automorphic and resolving systems are completed to involution. The resolving part of group foliation inherits finite-dimensional part of g...

near-fault ground motions with long-period pulses can place severe demands on structures near an active fault. these pulse-type ground motions can be represented by pulse sequences with simple shapes. half-sinusoidal pulse sequences are used to approximate recorded ground motions and dynamic responses of sdof system under the excitation of these pulse sequences are studied. four cases are consi...

in this paper the concept of homothetic dual exponential motions in d3 is discussed and theirvelocities obtained. due to the way in which the matter is presented, the paper gives some formula and factsabout dual exponential motions which are not generally known