The uncooled microbolometer has a severe temperature requirement for non-uniformity correction. An improved two-point non-uniformity correction method is proposed, which can operate in wider uniform substrate temperat...The uncooled microbolometer has a severe temperature requirement for non-uniformity correction. An improved two-point non-uniformity correction method is proposed, which can operate in wider uniform substrate temperatures. This method can control the bias voltage of MOS transistors by memory and DAC to meet two restrictions about responsivity and offset before traditional two-point calibration is implemented. The simulation results seem that this non-uniformity correction can work at uniform substrate temperature with fluctuant range of 4K.展开更多
Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually app...Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually applied. Purpose: To compare the correction effects of the phased-array uniformity enhancement (PURE), a calibration-based image non-uniformity correction method, among three different software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Material and Methods: Hepatobiliary-phase images of a total of 120 patients who underwent Gd-EOB-DTPA-enhanced MR imaging on the same 3T scanner were analyzed retrospectively. Forty patients each were examined using three software versions (DV25, DV25.1, and DV26). The effects of PURE were compared by visual assessment, histogram analysis of liver signal intensity, evaluation of the spatial distribution of correction effects, and evaluation of quantitative indices of liver parenchymal enhancement. Results: The visual assessment indicated the highest uniformity of PURE-corrected images for DV26, followed by DV25 and DV25.1. Histogram analysis of corrected images demonstrated significantly larger variations in liver signal for DV25.1 than for the other two versions. Although PURE caused a relative increase in pixel values for central and lateral regions, such effects were weaker for DV25.1 than for the other two versions. In the evaluation of quantitative indices of liver parenchymal enhancement, the liver-to-muscle ratio (LMR) was significantly higher for the corrected images than for the uncorrected images, but the liver-to-spleen ratio (LSR) showed no significant differences. For corrected images, the LMR was significantly higher for DV25 and DV26 than for DV25.1, but the LSR showed no significant differences among the three versions. Conclusion: There were differences in the effects of PURE among the three software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Even if the non-uniformity correction method has the same brand name, correction effects may differ depending on the software version, and these differences may affect visual and quantitative evaluations.展开更多
针对局部配电网中互联微电网系统的调度问题,提出了一种优化调度模型。首先,配电网调度层通过协调各微电网与配电网之间的交互功率来改善配电网的运行状况;然后,微电网层根据配电网层的优化调度结果制定生产计划,并建立基于储能系统荷...针对局部配电网中互联微电网系统的调度问题,提出了一种优化调度模型。首先,配电网调度层通过协调各微电网与配电网之间的交互功率来改善配电网的运行状况;然后,微电网层根据配电网层的优化调度结果制定生产计划,并建立基于储能系统荷电状态(state of charge,SOC)的阶梯式功率修正策略,以保证储能系统的可调度能力。选用全局搜索能力强的改进花朵授粉算法(flower pollination algorithm,FPA)求解配电网层优化调度模型,并以IEEE-14节点系统为算例进行仿真分析。结果表明:改进FPA算法的初始种群质量与收敛速度均有所提高;配电网的网损和微电网交互功率的波动性下降;各储能系统的SOC保持在0.25~0.6区间内。研究结果证明了优化调度模型的电网友好性和改进FPA算法的有效性,且阶梯式功率修正策略可以保证各储能系统的持续可调度能力。展开更多
文摘The uncooled microbolometer has a severe temperature requirement for non-uniformity correction. An improved two-point non-uniformity correction method is proposed, which can operate in wider uniform substrate temperatures. This method can control the bias voltage of MOS transistors by memory and DAC to meet two restrictions about responsivity and offset before traditional two-point calibration is implemented. The simulation results seem that this non-uniformity correction can work at uniform substrate temperature with fluctuant range of 4K.
文摘Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually applied. Purpose: To compare the correction effects of the phased-array uniformity enhancement (PURE), a calibration-based image non-uniformity correction method, among three different software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Material and Methods: Hepatobiliary-phase images of a total of 120 patients who underwent Gd-EOB-DTPA-enhanced MR imaging on the same 3T scanner were analyzed retrospectively. Forty patients each were examined using three software versions (DV25, DV25.1, and DV26). The effects of PURE were compared by visual assessment, histogram analysis of liver signal intensity, evaluation of the spatial distribution of correction effects, and evaluation of quantitative indices of liver parenchymal enhancement. Results: The visual assessment indicated the highest uniformity of PURE-corrected images for DV26, followed by DV25 and DV25.1. Histogram analysis of corrected images demonstrated significantly larger variations in liver signal for DV25.1 than for the other two versions. Although PURE caused a relative increase in pixel values for central and lateral regions, such effects were weaker for DV25.1 than for the other two versions. In the evaluation of quantitative indices of liver parenchymal enhancement, the liver-to-muscle ratio (LMR) was significantly higher for the corrected images than for the uncorrected images, but the liver-to-spleen ratio (LSR) showed no significant differences. For corrected images, the LMR was significantly higher for DV25 and DV26 than for DV25.1, but the LSR showed no significant differences among the three versions. Conclusion: There were differences in the effects of PURE among the three software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Even if the non-uniformity correction method has the same brand name, correction effects may differ depending on the software version, and these differences may affect visual and quantitative evaluations.
文摘针对局部配电网中互联微电网系统的调度问题,提出了一种优化调度模型。首先,配电网调度层通过协调各微电网与配电网之间的交互功率来改善配电网的运行状况;然后,微电网层根据配电网层的优化调度结果制定生产计划,并建立基于储能系统荷电状态(state of charge,SOC)的阶梯式功率修正策略,以保证储能系统的可调度能力。选用全局搜索能力强的改进花朵授粉算法(flower pollination algorithm,FPA)求解配电网层优化调度模型,并以IEEE-14节点系统为算例进行仿真分析。结果表明:改进FPA算法的初始种群质量与收敛速度均有所提高;配电网的网损和微电网交互功率的波动性下降;各储能系统的SOC保持在0.25~0.6区间内。研究结果证明了优化调度模型的电网友好性和改进FPA算法的有效性,且阶梯式功率修正策略可以保证各储能系统的持续可调度能力。
