射频识别RFID(Radio Frequency Identification)系统内的读卡器在识别大数量标签时常因信号的碰撞而导致系统识别效率降低.动态时隙冲突跟踪树算法DSCTTA(Dynamic Slots Collision Tracking Tree Algorithm)采用动态时隙应答机制可减少...射频识别RFID(Radio Frequency Identification)系统内的读卡器在识别大数量标签时常因信号的碰撞而导致系统识别效率降低.动态时隙冲突跟踪树算法DSCTTA(Dynamic Slots Collision Tracking Tree Algorithm)采用动态时隙应答机制可减少前缀开销和迭代开销,但会产生大量空闲时隙.本文将DSCTTA和比特转换方式(BCM)相结合,得到改进型动态时隙冲突跟踪树标签防碰撞算法(IDSCTTA)以防止标签冲突,加快标签识别速度.理论分析及仿真结果表明,IDSCTTA不仅具有DSCTTA的全部优点,而且能够有效地减小识别时延和提高时隙效率,并且标签数目越大,算法性能越优越.展开更多
Any unitary transformation can be decomposed into a product of a group of near-trivial transformations. We investigate in detail theconstruction of universal quantum circuit of near trivial transformations. We first c...Any unitary transformation can be decomposed into a product of a group of near-trivial transformations. We investigate in detail theconstruction of universal quantum circuit of near trivial transformations. We first construct two universal quantum circuits whichcan implement any single-qubit rotation Ry(θ) and Rz(θ) within any given precision, and then we construct universal quantum circuitimplementing any single-qubit transformation within any given precision. Finally, a universal quantum circuit implementing anyn-qubit near-trivial transformation is constructed using the universal quantum circuits of Ry(θ) and Rz(θ). In the universal quantumcircuit presented, each quantum transformation is encoded to a bit string which is used as ancillary inputs. The output of the circuitconsists of the related bit string and the result of near-trivial transformation. Our result may be useful for the design of universalquantum computer in the future.展开更多
We present two robust quantum secure direct communication (QSDC) schemes with a quantum one-time pad over a collective-noise channel. Each logical qubit is made up of two physical qubits and it is invariant over a col...We present two robust quantum secure direct communication (QSDC) schemes with a quantum one-time pad over a collective-noise channel. Each logical qubit is made up of two physical qubits and it is invariant over a collective-noise channel. The two photons in each logical qubit can be produced with a practically entangled source, i.e., a parametric down-conversion source with a beta barium borate crystal and a pump pulse of ultraviolet light. The information is encoded on each logical qubit with two logical unitary operations, which will not destroy the antinoise feather of the quantum systems. The receiver Bob can read out the sender's message directly with two single-photon measurements on each logical qubit, instead of Bell-state measurements, which will make these protocols more convenient in a practical application. With current technology, our two robust QSDC schemes are feasible and may be optimal ones.展开更多
文摘射频识别RFID(Radio Frequency Identification)系统内的读卡器在识别大数量标签时常因信号的碰撞而导致系统识别效率降低.动态时隙冲突跟踪树算法DSCTTA(Dynamic Slots Collision Tracking Tree Algorithm)采用动态时隙应答机制可减少前缀开销和迭代开销,但会产生大量空闲时隙.本文将DSCTTA和比特转换方式(BCM)相结合,得到改进型动态时隙冲突跟踪树标签防碰撞算法(IDSCTTA)以防止标签冲突,加快标签识别速度.理论分析及仿真结果表明,IDSCTTA不仅具有DSCTTA的全部优点,而且能够有效地减小识别时延和提高时隙效率,并且标签数目越大,算法性能越优越.
基金supported by the National Natural Science Foundation of China (Grant No. 60573051)
文摘Any unitary transformation can be decomposed into a product of a group of near-trivial transformations. We investigate in detail theconstruction of universal quantum circuit of near trivial transformations. We first construct two universal quantum circuits whichcan implement any single-qubit rotation Ry(θ) and Rz(θ) within any given precision, and then we construct universal quantum circuitimplementing any single-qubit transformation within any given precision. Finally, a universal quantum circuit implementing anyn-qubit near-trivial transformation is constructed using the universal quantum circuits of Ry(θ) and Rz(θ). In the universal quantumcircuit presented, each quantum transformation is encoded to a bit string which is used as ancillary inputs. The output of the circuitconsists of the related bit string and the result of near-trivial transformation. Our result may be useful for the design of universalquantum computer in the future.
基金supported by the Natural Science Foundation of Jiangsu Provincial Universities (Grant No. 10KJB180004)the National Natural Science Foundation of China (Grant No. 10847147)
文摘We present two robust quantum secure direct communication (QSDC) schemes with a quantum one-time pad over a collective-noise channel. Each logical qubit is made up of two physical qubits and it is invariant over a collective-noise channel. The two photons in each logical qubit can be produced with a practically entangled source, i.e., a parametric down-conversion source with a beta barium borate crystal and a pump pulse of ultraviolet light. The information is encoded on each logical qubit with two logical unitary operations, which will not destroy the antinoise feather of the quantum systems. The receiver Bob can read out the sender's message directly with two single-photon measurements on each logical qubit, instead of Bell-state measurements, which will make these protocols more convenient in a practical application. With current technology, our two robust QSDC schemes are feasible and may be optimal ones.
