The conventional orthogonal space-time block code (OSTBC) with limited feedback has fixed p-1?feedback bits for the specific ntp?transmit antennas. A new partial feedback based OSTBC which provides flexible feedback b...The conventional orthogonal space-time block code (OSTBC) with limited feedback has fixed p-1?feedback bits for the specific ntp?transmit antennas. A new partial feedback based OSTBC which provides flexible feedback bits is proposed in this paper. The proposed scheme inherits the properties of having a simple decoder and the full diversity of OSTBC, moreover, preserves full data rate. Simulation results show that for?ntp transmit antennas, the proposed scheme has the similar performance with the conventional one by using p-1?feedback bits, whereas has the better performance with more feedback bits.展开更多
The difference in link condition of broadcast/ multicast users and the limitation of uplink resource, make it difficult to utilize adaptive modulation and coding （AMC） in the enhanced multimedia broadcast and multic...The difference in link condition of broadcast/ multicast users and the limitation of uplink resource, make it difficult to utilize adaptive modulation and coding （AMC） in the enhanced multimedia broadcast and multicast service （E-MBMS） network. To obtain the improvement of system throughput, this study proposes an adaptive modulation and coding scheme based on partial feedback, by which only partial users whose channel qualities are lower than the system threshold need to make a response to the modulation coding scheme （MCS） adaptation procedure. By this investigation, an adaptive scheme can be introduced in the E-MBMS network. Both the theoretical analysis and simulation results demonstrate the efficiency of the proposed strategy, in which the performance is close to the ideal one and has a significant throughput improvement when compared with that of the fixed MCS transmission scheme.展开更多
In this paper,the numerical approximation of a Timoshenko beam with bound- ary feedback is considered.We derived a linearized three-level difference scheme on uniform meshes by the method of reduction of order for a T...In this paper,the numerical approximation of a Timoshenko beam with bound- ary feedback is considered.We derived a linearized three-level difference scheme on uniform meshes by the method of reduction of order for a Timoshenko beam with boundary feedback.It is proved that the scheme is uniquely solvable,unconditionally stable and second order convergent in L_∞norm by using the discrete energy method. A numerical example is presented to verify the theoretical results.展开更多
A feedback control optimization method of partially observable linear structures via stationary response is proposed and analyzed with linear building structures equipped with control devices and sensors. First, the p...A feedback control optimization method of partially observable linear structures via stationary response is proposed and analyzed with linear building structures equipped with control devices and sensors. First, the partially observable control problem of the structure under horizontal ground acceleration excitation is converted into a completely observable control problem. Then the It6 stochastic differential equations of the system are derived based on the stochastic averaging method for quasi-integrable Hamiltonian systems and the stationary solution to the Fokker-Plank-Kolmogorov （FPK） equation associated with the It6 equations is obtained. The performance index in terms of the mean system energy and mean square control force is established and the optimal control force is obtained by minimizing the performance index. Finally, the numerical results for a three-story building structure model under E1 Centro, Hachinohe, Northridge and Kobe earthquake excitations are given to illustrate the application and the effectiveness of the proposed method.展开更多
干涉型光纤超声传感是一种高灵敏度的局部放电检测方法,但其现场应用时可能受到环境中低频振动噪声的干扰,降低检测灵敏度。为此,提出了相位跟踪反馈方法,确定了反馈系统参数;然后建立了真型126k V GIS局部放电超声传感研究平台,该平台...干涉型光纤超声传感是一种高灵敏度的局部放电检测方法,但其现场应用时可能受到环境中低频振动噪声的干扰,降低检测灵敏度。为此,提出了相位跟踪反馈方法,确定了反馈系统参数;然后建立了真型126k V GIS局部放电超声传感研究平台,该平台可模拟现场GIS电动力及开关动作所产生的振动噪声;最后,开展了GIS局部放电检测试验。研究结果表明:相位跟踪反馈可以补偿干涉传感系统中的相位变化,保证了传感系统灵敏度的稳定性;相位跟踪反馈方法可有效抑制由1.8 kHz以下低频噪声引发的相位衰落问题;采用相位跟踪反馈方法后,干涉型光纤超声局部放电传感系统测量灵敏度优于传统压电陶瓷传感系统,满足现场应用需求。展开更多
文摘The conventional orthogonal space-time block code (OSTBC) with limited feedback has fixed p-1?feedback bits for the specific ntp?transmit antennas. A new partial feedback based OSTBC which provides flexible feedback bits is proposed in this paper. The proposed scheme inherits the properties of having a simple decoder and the full diversity of OSTBC, moreover, preserves full data rate. Simulation results show that for?ntp transmit antennas, the proposed scheme has the similar performance with the conventional one by using p-1?feedback bits, whereas has the better performance with more feedback bits.
基金the National Natural Science Foundation of China（60572120）the Hi-Tech Research and Development Program of China（2006AA01 Z257）.
文摘The difference in link condition of broadcast/ multicast users and the limitation of uplink resource, make it difficult to utilize adaptive modulation and coding （AMC） in the enhanced multimedia broadcast and multicast service （E-MBMS） network. To obtain the improvement of system throughput, this study proposes an adaptive modulation and coding scheme based on partial feedback, by which only partial users whose channel qualities are lower than the system threshold need to make a response to the modulation coding scheme （MCS） adaptation procedure. By this investigation, an adaptive scheme can be introduced in the E-MBMS network. Both the theoretical analysis and simulation results demonstrate the efficiency of the proposed strategy, in which the performance is close to the ideal one and has a significant throughput improvement when compared with that of the fixed MCS transmission scheme.
基金Supported in part by the Chinese Outstanding Youth Science Foundation(69925308)supported by Program for Changjiang Scholars and Innovative Research Team in University
文摘In this paper,the numerical approximation of a Timoshenko beam with bound- ary feedback is considered.We derived a linearized three-level difference scheme on uniform meshes by the method of reduction of order for a Timoshenko beam with boundary feedback.It is proved that the scheme is uniquely solvable,unconditionally stable and second order convergent in L_∞norm by using the discrete energy method. A numerical example is presented to verify the theoretical results.
基金Project supported by the National Natural Science Foundation of China under a key grant (No.10332030)the Research Fund for the Doctoral Program of Higher Education of China (No.20060335125)the Zhejiang Provincial Natural Science Foundation of China (No.Y607087).
文摘A feedback control optimization method of partially observable linear structures via stationary response is proposed and analyzed with linear building structures equipped with control devices and sensors. First, the partially observable control problem of the structure under horizontal ground acceleration excitation is converted into a completely observable control problem. Then the It6 stochastic differential equations of the system are derived based on the stochastic averaging method for quasi-integrable Hamiltonian systems and the stationary solution to the Fokker-Plank-Kolmogorov （FPK） equation associated with the It6 equations is obtained. The performance index in terms of the mean system energy and mean square control force is established and the optimal control force is obtained by minimizing the performance index. Finally, the numerical results for a three-story building structure model under E1 Centro, Hachinohe, Northridge and Kobe earthquake excitations are given to illustrate the application and the effectiveness of the proposed method.
文摘干涉型光纤超声传感是一种高灵敏度的局部放电检测方法,但其现场应用时可能受到环境中低频振动噪声的干扰,降低检测灵敏度。为此,提出了相位跟踪反馈方法,确定了反馈系统参数;然后建立了真型126k V GIS局部放电超声传感研究平台,该平台可模拟现场GIS电动力及开关动作所产生的振动噪声;最后,开展了GIS局部放电检测试验。研究结果表明:相位跟踪反馈可以补偿干涉传感系统中的相位变化,保证了传感系统灵敏度的稳定性;相位跟踪反馈方法可有效抑制由1.8 kHz以下低频噪声引发的相位衰落问题;采用相位跟踪反馈方法后,干涉型光纤超声局部放电传感系统测量灵敏度优于传统压电陶瓷传感系统,满足现场应用需求。
