图书馆内书架、墙壁等障碍物会导致射频识别(Radio Frequency Identification,RFID)信号反射、折射,形成多路径效应,使读写器接收到的信号是多个路径信号的叠加,造成信号失真和距离检测偏差。因此,提出基于电子标签距离一致性检测的图...图书馆内书架、墙壁等障碍物会导致射频识别(Radio Frequency Identification,RFID)信号反射、折射,形成多路径效应,使读写器接收到的信号是多个路径信号的叠加,造成信号失真和距离检测偏差。因此,提出基于电子标签距离一致性检测的图书馆内目标图书定位方法。将图书馆内所有图书贴上电子标签,采用小波阈值方法对电子标签接收信号去噪,减少多路径效应产生的干扰,提高接收信号的精准度。以去噪后的电子标签接收信号为基础,选取信号接受强度指标(Received Signal Strength Indicator,RSSI)进行电子标签距离一致性检测。确保在不同距离下,读写器都能准确读取到电子标签反射的接收信号。由此,建立目标图书定位模型。通过读写器读取目标图书和实体参考图书RSSI值确定书架,引入VIRE算法和牛顿插值法计算虚拟图书RSSI值,再根据虚拟图书RSSI值确定目标图书位置,实现图书馆目标图书定位。实验结果表明:所提方法的定位误差始终保持在0.2以下,具有较高的定位准确度,能够在面积大、书本排放密集的图书馆环境中完成目标图书的精准定位。展开更多
The relationships between fatigue threshold △Kth and the initial yield .strength σ0 of normalized 1035 steel after various prestrain (at fist, second and third hardening stages respectively) were investigated throug...The relationships between fatigue threshold △Kth and the initial yield .strength σ0 of normalized 1035 steel after various prestrain (at fist, second and third hardening stages respectively) were investigated through the analysis of theσ-εcurves and transmission electron microscope (TEM). After prestraining at first or second hardening stage, there is a marked drop in the values of △Kth and σ0. This is in correspondence with the depinning of the solute atoms from the dislocation lines in the Cottrell atmosphere.At the third hardening stage of prestrain the fatigue threshold increases rapidly and △Kth is even 1.6 times as large as the original value. This is because at this stage no dislocation-cell free areas can be found and the refinement of the dislocation cells occurs with the increase in the prestrain level.展开更多
文摘图书馆内书架、墙壁等障碍物会导致射频识别(Radio Frequency Identification,RFID)信号反射、折射,形成多路径效应,使读写器接收到的信号是多个路径信号的叠加,造成信号失真和距离检测偏差。因此,提出基于电子标签距离一致性检测的图书馆内目标图书定位方法。将图书馆内所有图书贴上电子标签,采用小波阈值方法对电子标签接收信号去噪,减少多路径效应产生的干扰,提高接收信号的精准度。以去噪后的电子标签接收信号为基础,选取信号接受强度指标(Received Signal Strength Indicator,RSSI)进行电子标签距离一致性检测。确保在不同距离下,读写器都能准确读取到电子标签反射的接收信号。由此,建立目标图书定位模型。通过读写器读取目标图书和实体参考图书RSSI值确定书架,引入VIRE算法和牛顿插值法计算虚拟图书RSSI值,再根据虚拟图书RSSI值确定目标图书位置,实现图书馆目标图书定位。实验结果表明:所提方法的定位误差始终保持在0.2以下,具有较高的定位准确度,能够在面积大、书本排放密集的图书馆环境中完成目标图书的精准定位。
文摘The relationships between fatigue threshold △Kth and the initial yield .strength σ0 of normalized 1035 steel after various prestrain (at fist, second and third hardening stages respectively) were investigated through the analysis of theσ-εcurves and transmission electron microscope (TEM). After prestraining at first or second hardening stage, there is a marked drop in the values of △Kth and σ0. This is in correspondence with the depinning of the solute atoms from the dislocation lines in the Cottrell atmosphere.At the third hardening stage of prestrain the fatigue threshold increases rapidly and △Kth is even 1.6 times as large as the original value. This is because at this stage no dislocation-cell free areas can be found and the refinement of the dislocation cells occurs with the increase in the prestrain level.
