yi kai | Central South University of Forestry And Technology (original) (raw)
Address: Changsha, China
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Papers by yi kai
A LONG STORY ABOUT A LITTLE KING
International Journal of Advanced Manufacturing Technology, 2004
The traditional formulae for degree of freedom are not valid in solving the platform for certain ... more The traditional formulae for degree of freedom are not valid in solving the platform for certain complex spatial parallel mechanisms. Therefore, by uniformly depicting the kinematic and geometric constraints of a mechanism with a screw theory, we put forward a new method to study the degree of freedom for the platform of spatial parallel mechanisms. This method should solve the analysis and calculation problems of the degree of freedom in many complex spatial parallel mechanisms, which may not always be solved correctly with traditional formulae.
Computing Research Repository, 2009
We establish methods for quantum state tomography based on compressed sensing. These methods are ... more We establish methods for quantum state tomography based on compressed sensing. These methods are specialized for quantum states that are fairly pure, and they offer a significant performance improvement on large quantum systems. In particular, they are able to reconstruct an unknown density matrix of dimension d and rank r using O(rd log^2 d) measurement settings, compared to standard methods that require d^2 settings. Our methods have several features that make them amenable to experimental implementation: they require only simple Pauli measurements, use fast convex optimization, are stable against noise, and can be applied to states that are only approximately low-rank. The acquired data can be used to certify that the state is indeed close to pure, so no a priori assumptions are needed. We present both theoretical bounds and numerical simulations.
Mechanism and Machine Theory, 2006
In this paper, we propound an analogous symmetric theorem of workspace for spatial parallel manip... more In this paper, we propound an analogous symmetric theorem of workspace for spatial parallel manipulators with identical kinematic chains, and then present a strict mathematic proof by splitting the problem into planar symmetry, rotational axis symmetry and point symmetry (centrosymmetry). Examples demonstrate that this theorem can be utilized to investigate the geometry shapes of the workspace and to guide the conceptual design of spatial parallel manipulators, especially for those complicated spatial parallel manipulators with full degrees of freedom (DoF). The theorem offers a concrete safeguard for the workspace analysis of any symmetric spatial parallel manipulators.
A LONG STORY ABOUT A LITTLE KING
International Journal of Advanced Manufacturing Technology, 2004
The traditional formulae for degree of freedom are not valid in solving the platform for certain ... more The traditional formulae for degree of freedom are not valid in solving the platform for certain complex spatial parallel mechanisms. Therefore, by uniformly depicting the kinematic and geometric constraints of a mechanism with a screw theory, we put forward a new method to study the degree of freedom for the platform of spatial parallel mechanisms. This method should solve the analysis and calculation problems of the degree of freedom in many complex spatial parallel mechanisms, which may not always be solved correctly with traditional formulae.
Computing Research Repository, 2009
We establish methods for quantum state tomography based on compressed sensing. These methods are ... more We establish methods for quantum state tomography based on compressed sensing. These methods are specialized for quantum states that are fairly pure, and they offer a significant performance improvement on large quantum systems. In particular, they are able to reconstruct an unknown density matrix of dimension d and rank r using O(rd log^2 d) measurement settings, compared to standard methods that require d^2 settings. Our methods have several features that make them amenable to experimental implementation: they require only simple Pauli measurements, use fast convex optimization, are stable against noise, and can be applied to states that are only approximately low-rank. The acquired data can be used to certify that the state is indeed close to pure, so no a priori assumptions are needed. We present both theoretical bounds and numerical simulations.
Mechanism and Machine Theory, 2006
In this paper, we propound an analogous symmetric theorem of workspace for spatial parallel manip... more In this paper, we propound an analogous symmetric theorem of workspace for spatial parallel manipulators with identical kinematic chains, and then present a strict mathematic proof by splitting the problem into planar symmetry, rotational axis symmetry and point symmetry (centrosymmetry). Examples demonstrate that this theorem can be utilized to investigate the geometry shapes of the workspace and to guide the conceptual design of spatial parallel manipulators, especially for those complicated spatial parallel manipulators with full degrees of freedom (DoF). The theorem offers a concrete safeguard for the workspace analysis of any symmetric spatial parallel manipulators.