Introduction: Ordered subset expectation maximization (OSEM), is an effective iterative method for SPECT image reconstruction. The aim of this study is the evaluation of the role of system matrix in OSEM image reconstruction method using four different physical beam radiation models with three detection configurations. Methods: SPECT was done with an arc of 180 deg...

For the nonlinear eigenvalue problem T (λ)x = 0 we consider a Jacobi–Davidson type iterative projection method. The resulting projected nonlinear eigenvalue problems are solved by inverse iteration. The method is applied to a rational eigenvalue problem governing damped vibrations of a structure.

Comparing with traditional fixed formation for a group of dynamical systems, time-varying formation can produce the following benefits: i) covering the greater part of complex environments; ii) collision avoidance. This paper studies the time-varying formation tracking for multiple manipulator systems (MMSs) under fixed and switching directed graphs with a dynamic leader, whose acceleration can...

In this paper, we design a nonlinear controller for the kinematic model of an underactuated rigid spacecraft that ensures uniform, ultimately bounded (UUB) tracking provided the initial errors are selected sufficiently small. The result is achieved via a judicious formulation of the spacecraft kinematics and the novel design of a Lyapunov-based controller. We also discuss how standard backstepp...

A descriptive study of the biomechanical variables of the walking patterns of the fit and healtky elderly compared with those of young adults revealed several signzficant dzfferences. The walking patterns of 15 elderly subjects, selected for their active life style and screened for any gaitor balance-related pathological conditions, were analyzed. Kinematic and kinetic data for a minimum of 10 ...

The motion planning approach of a multi-fingered robot for carton flap folding operations has been newly developed. This approach considers the loci of the tool center point for carton flap folding operations. Also that considers the pushing or fixing points of the carton flap. This approach is calculated from the rotating angle for carton flap folding and the position of a robot finger tip in ...

Most of the methods to date on bilateral control of nonlinear teleoperation systems lead to nonlinear and coupled closed-loop dynamics even in the ideal case of perfect knowledge of the master, the slave, the human operator and the environment. Consequently, the transparency of these closed-loop systems is difficult to study. In comparison, inverse dynamics controllers can deal with the nonline...

We present a method of reconstructing the region of origin and trajectories for particles given impact directions and positions. This method works for nonlinear trajectories, such as parabolic motion or motion with drag if given drag parameters. Our method works if given the impact speeds as well, or they can be estimated using a similar total initial energy prior. We apply our algorithm to the...

In this paper, we introduce a hexapedal locomotion controller that simulation evidence suggests will be capable of driving our RHex robot at speeds exceeding five body lengths per second with reliable stability and rapid maneuverability. We use a low dimensional passively compliant biped as n "template" a control target !or the alternating tripod gait of the physical machine. We impose upon the...