Cooperative Multi-Point (CoMP) has emerged as a new paradigm to improve both average cell and cell edge throughput in cellular networks. However, the performance is significantly degraded due to Out-of-Group Interference (OGI). One way to mitigate OGI is to restrict the interfering signal to lie inside the null space of the unintended receiver. Yet, accurately tracking this null space is a chal...

As well known, robot manipulator is utilized in many industrial fields. However manipulator motion has a single function at most and is so limited because of low degree-offreedom motion. To improve this issue, it is necessary for the robot manipulator to have redundant degree-of-freedom motion. The motion spaces of redundant manipulator are divided into work space motion and null space motion. ...

Let T be a quadratic operator on a complex Hilbert space H. We show that T can be written as a product of two positive contractions if and only if T is of the form aI ⊕ bI ⊕ ( aI P 0 bI ) on H1 ⊕H2 ⊕ (H3 ⊕H3) for some a, b ∈ [0, 1] and strictly positive operator P with ‖P‖ ≤ | √ a− √ b| √ (1− a)(1− b). Also, we give a necessary condition for a bounded linear operator T with operator matrix ( T1...

A bstract We construct the boundary phase space in D -dimensional Einstein gravity with a generic given co-dimension one null surface $$ \mathcal{N} N as boundary. The associated symmetry algebra is semi-direct sum of diffeomorphisms and Weyl rescalings. It generated by towers charges that are functions over ...

Based on the fundamental theories of null curves in Minkowski 3-space, Darboux mate a curve are defined which can be regarded as kind extension for Bertrand and Mannheim 3-space. The relationships pairs explored their expression forms presented explicitly.