We investigated the association of time to prostate-specific antigen nadir （TTPN） and logarithm of prostate-specific antigen velocity after progression Log（PSAVAP） in metastatic prostate cancer with prior primary ...We investigated the association of time to prostate-specific antigen nadir （TTPN） and logarithm of prostate-specific antigen velocity after progression Log（PSAVAP） in metastatic prostate cancer with prior primary androgen deprivation therapy （ADT）. All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. Patients who developed disease progression were included in the subsequent analyses. Patients were categorized into three groups according to their TTPN： TTPN of 〈3 months, 3-17 months, and 〉17 months. We compared the Log（PSAVAP） between the different TTPN groups using Mann-Whitney U-test and Kruskal-Wallis test. Further multiple linear regression analyses on Log（PSAVAP） were performed to adjust for other potential confounding factors. Among 419 patients who were treated with primary ADT, 306 patients developed disease progression with a median follow-up of 28 months, Longer TTPN was associated with lower Log（PSAVAP） （P = 0.008） within all subgroup analyses （TTPN of 〈3 vs 3-17 months, P = 0.020; TTPN of 3-17 vs 〉17 months, P = 0.009; and TTPN of 〈3 vs 〉17 months, P = 0.001）. Upon multiple linear regression analyses, baseline PSA （regression coefficient 0.001, P = 0.045）, PSA nadir （regression coefficient 0.002, P = 0.040）, and TTPN （regression coefficient -0.030, P = 0.001） were the three factors that were significantly associated with Log（PSAVAP）. In conclusion, a longer TTPN was associated with lower Log（PSAVAP） in metastatic prostate cancer patients following primary ADT. TTPN cut-offs at 3 months and 17 months appeared to have prognostic significance in predicting Log（PSAVAP）. TTPN may serve as a good prognostic indicator in deciding the treatment strategy in patients with disease progression.展开更多
Docetaxel-based chemotherapy remains the first-line treatment for patients with metastatic castration-resistant prostate cancer （mCRPC） in China; however, the prognostic factors associated with effects in these pati...Docetaxel-based chemotherapy remains the first-line treatment for patients with metastatic castration-resistant prostate cancer （mCRPC） in China; however, the prognostic factors associated with effects in these patients are still controversial. In this study, we retrospectively reviewed the data from 71 eligible Chinese patients who received docetaxel chemotherapy from 2009 to 2016 in our hospital and experienced a reduction of prostate-specific antigen （PSA） level 〉50% during the treatment and investigated the potential role of time to nadir （TTN） of PSA. TTN was defined as the time from start of chemotherapy to the nadir of PSA level during the treatment. Multivariable Cox regression models and Kaplan-Meier analysis were used to predict overall survival （OS）. In these patients, the median of TTN was 17 weeks. Patients with TTN ≥17 weeks had a longer response time to chemotherapy compared to TTN 〈17 weeks （42.83 vs 21.50 weeks, P 〈 0.001）. The time to PSA progression in patients with TTN ：〉17 weeks was 11.44 weeks compared to 5.63 weeks when TTN was 〈17 weeks. We found several factors to be associated with OS, including TTN （hazard ratio [HR]. 3.937, 95% confidence interval [CI]： 1.502-10.309, P = 0.005）, PSA level at the diagnosis of cancer （HR： 4,337, 95% CI： 1.616-11.645, P= 0.004）, duration of initial androgen deprivation therapy （HR： 2.982, 95% CI： 1.104-8.045, P= 0.031）, neutrophil-to-lymphocyte ratio （HR： 3.963, 95% CI： 1.380-11.384, P = 0.011）, and total PSA response （Class 1 [〈0 response] compared to Class 2 [0-50% response], HR： 3.978, 95% CI： 1.278-12.387, P = 0.017）. In conclusion, TTN of PSA remains an important prognostic marker in predicting therapeutic outcome in Chinese population who receive chemotherapy for mCRPC and have 〉50% PSA remission.展开更多
The integration of optical images and elevation data is of great importance for 3D-assisted mapping applications. Very high resolution (VHR) satellite images provide ideal geo-data for mapping building information. Si...The integration of optical images and elevation data is of great importance for 3D-assisted mapping applications. Very high resolution (VHR) satellite images provide ideal geo-data for mapping building information. Since buildings are inherently elevated objects, these images need to be co-registered with their elevation data for reliable building detection results. However, accurate co-registration is extremely difficult for off-nadir VHR images acquired over dense urban areas. Therefore, this research proposes a Disparity-Based Elevation Co-Registration (DECR) method for generating a Line-of-Sight Digital Surface Model (LoS-DSM) to efficiently achieve image-elevation data co-registration with pixel-level accuracy. Relative to the traditional photogrammetric approach, the RMSE value of the derived elevations is found to be less than 2 pixels. The applicability of the DECR method is demonstrated through elevation-based building detection (EBD) in a challenging dense urban area. The quality of the detection result is found to be more than 90%. Additionally, the detected objects were geo-referenced successfully to their correct ground locations to allow direct integration with other maps. In comparison to the original LoS-DSM development algorithm, the DECR algorithm is more efficient by reducing the calculation steps, preserving the co-registration accuracy, and minimizing the need for elevation normalization in dense urban areas.展开更多
The baseline roll and length errors for wide-swath altimeters are major error sources in sea surface measurements that exhibit strong spatial characteristics in the cross-track direction.These errors can be identified...The baseline roll and length errors for wide-swath altimeters are major error sources in sea surface measurements that exhibit strong spatial characteristics in the cross-track direction.These errors can be identified and estimated in accordance with height differences at crossover points generated with nadir altimeters after excluding the interference from other error sources.Most of the wide-swath altimeter baseline estimation methods considered only the roll error in previous studies.A numerical simulation was conducted in this study using nadir altimeters to estimate the roll and length errors simultaneously to provide a selectable scheme for baseline error estimation and correction for future wide-swath altimeters.Results based on the parameters of the surface water and ocean topography mission and Sentinel-3A show that the correlation coefficient of the roll error between the estimated and simulated values is 0.89,while the correlation coefficient of the length error is 0.85.The sea surface height root mean square error(RMSE)can be reduced from 12.18 cm to 6.45 cm based on the two estimated results.The estimation effect can be increased by using multiple nadir altimeters to form an observation constellation.The numerical simulation of the five nadir altimeter constellation shows that the correlation coefficients of the roll and length errors would increase to 0.97,which reduces the sea surface height RMSE to 2.88 cm.In addition,the stability of this method is indicated in simulation experiments,which introduce different degrees of sea state errors.展开更多
Cross-regional high voltage direct current(HVDC)systems bring remarkable renewable power injections to the receiver side of power grids.However,HVDC failures result in large disturbances to receivers and cause critica...Cross-regional high voltage direct current(HVDC)systems bring remarkable renewable power injections to the receiver side of power grids.However,HVDC failures result in large disturbances to receivers and cause critical frequency security problems.High renewable energy penetration also reduces the system inertia and damping coefficients.Thus,some nodal frequency nadirs may be much lower than those calculated by the center-of-inertia(COI)and may trigger low-frequency protection.Energy storage is a promising solution for frequency-related problems.In this study,we build an energy storage planning model considering both COI and nodal frequency security constraints.The energy storage capacities and locations are determined in the planning scheme based on year-round operations.First,we carry out a year-round COI-frequency-constrained unit commitment to obtain comprehensive operation modes.Next,we propose a hybrid data-model driven approach to generate nodal frequency security constraints for extensive operation modes effectively.Finally,we achieve optimal energy storage planning with both COI and nodal frequency constraints.Case studies on a modified RTS-79 test system and a 1089-bus power system in practical in Jiangsu,China,verify the effectiveness of the proposed methods.展开更多
新型电力系统的频率动态过程受到新能源机组故障穿越行为的显著影响,目前只能通过机电暂态仿真进行精准的暂态频率安全评估,在线应用困难。为此,该文提出一种基于关键准稳态计算的暂态频率安全定量评估方法,通过直接计算故障过程中的若...新型电力系统的频率动态过程受到新能源机组故障穿越行为的显著影响,目前只能通过机电暂态仿真进行精准的暂态频率安全评估,在线应用困难。为此,该文提出一种基于关键准稳态计算的暂态频率安全定量评估方法,通过直接计算故障过程中的若干个关键准稳态断面从而有效判断各新能源机组运行状态,进而实现暂态过程中频率安全指标的准确快速计算。具体而言,首先提出一种故障过程中关键准稳态计算方法,并据此评估系统最大频率变化率。其次,通过引入系统频率变量,提出一种直接计算故障后稳态频率的通用方法。最后,结合新能源机组各状态下的功率缺额,建立了基于关键准稳态的平均系统频率(average system frequency based on quasi-steady-state,QSS-ASF)模型,利用该模型仿真能够快速预测出故障发生后的频率最低点。仿真结果表明,所提方法在不同扰动及电源结构下均可准确判断新能源机组状态,各项频率安全指标评估误差均低于2%,兼具准确性与高效性。展开更多
电网受扰后频率最低点预测对新型电力系统的频率安全评估非常重要,而目前已有频率动态分析模型较难快速、准确、灵活地预测电网受扰后频率最低点,其中同步发电机调速系统的低阶通用建模以及新能源接入的影响建模是主要挑战。首先提出了...电网受扰后频率最低点预测对新型电力系统的频率安全评估非常重要,而目前已有频率动态分析模型较难快速、准确、灵活地预测电网受扰后频率最低点,其中同步发电机调速系统的低阶通用建模以及新能源接入的影响建模是主要挑战。首先提出了充分考虑频率响应特性的发电机调速系统低阶通用模型,结合新能源场站的通用频率响应模型,建立了新能源接入电网的通用平均系统频率(generic average system frequency,G-ASF)模型,在保证准确度的同时有效降低了模型阶数。然后,基于G-ASF模型直接预测电网在给定功率损失下的频率最低点。最后,在IEEE 3机9节点系统以及含新能源的IEEE 10机39节点系统中进行了仿真,结果表明提出的模型和方法在不同扰动或不同系统结构下均能准确预测频率最低点,且能够用于快速计算频率安全约束下的新能源渗透率极限值,验证了模型的准确性和通用性。展开更多
文摘We investigated the association of time to prostate-specific antigen nadir （TTPN） and logarithm of prostate-specific antigen velocity after progression Log（PSAVAP） in metastatic prostate cancer with prior primary androgen deprivation therapy （ADT）. All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. Patients who developed disease progression were included in the subsequent analyses. Patients were categorized into three groups according to their TTPN： TTPN of 〈3 months, 3-17 months, and 〉17 months. We compared the Log（PSAVAP） between the different TTPN groups using Mann-Whitney U-test and Kruskal-Wallis test. Further multiple linear regression analyses on Log（PSAVAP） were performed to adjust for other potential confounding factors. Among 419 patients who were treated with primary ADT, 306 patients developed disease progression with a median follow-up of 28 months, Longer TTPN was associated with lower Log（PSAVAP） （P = 0.008） within all subgroup analyses （TTPN of 〈3 vs 3-17 months, P = 0.020; TTPN of 3-17 vs 〉17 months, P = 0.009; and TTPN of 〈3 vs 〉17 months, P = 0.001）. Upon multiple linear regression analyses, baseline PSA （regression coefficient 0.001, P = 0.045）, PSA nadir （regression coefficient 0.002, P = 0.040）, and TTPN （regression coefficient -0.030, P = 0.001） were the three factors that were significantly associated with Log（PSAVAP）. In conclusion, a longer TTPN was associated with lower Log（PSAVAP） in metastatic prostate cancer patients following primary ADT. TTPN cut-offs at 3 months and 17 months appeared to have prognostic significance in predicting Log（PSAVAP）. TTPN may serve as a good prognostic indicator in deciding the treatment strategy in patients with disease progression.
基金This study was partially supported by the National Natural Science Foundation of China （NSFC 81202014 to KJW, NSFC 81130041 to DLH） and the Fundamental Research Funds for the Central Universities （to KIW）.
文摘Docetaxel-based chemotherapy remains the first-line treatment for patients with metastatic castration-resistant prostate cancer （mCRPC） in China; however, the prognostic factors associated with effects in these patients are still controversial. In this study, we retrospectively reviewed the data from 71 eligible Chinese patients who received docetaxel chemotherapy from 2009 to 2016 in our hospital and experienced a reduction of prostate-specific antigen （PSA） level 〉50% during the treatment and investigated the potential role of time to nadir （TTN） of PSA. TTN was defined as the time from start of chemotherapy to the nadir of PSA level during the treatment. Multivariable Cox regression models and Kaplan-Meier analysis were used to predict overall survival （OS）. In these patients, the median of TTN was 17 weeks. Patients with TTN ≥17 weeks had a longer response time to chemotherapy compared to TTN 〈17 weeks （42.83 vs 21.50 weeks, P 〈 0.001）. The time to PSA progression in patients with TTN ：〉17 weeks was 11.44 weeks compared to 5.63 weeks when TTN was 〈17 weeks. We found several factors to be associated with OS, including TTN （hazard ratio [HR]. 3.937, 95% confidence interval [CI]： 1.502-10.309, P = 0.005）, PSA level at the diagnosis of cancer （HR： 4,337, 95% CI： 1.616-11.645, P= 0.004）, duration of initial androgen deprivation therapy （HR： 2.982, 95% CI： 1.104-8.045, P= 0.031）, neutrophil-to-lymphocyte ratio （HR： 3.963, 95% CI： 1.380-11.384, P = 0.011）, and total PSA response （Class 1 [〈0 response] compared to Class 2 [0-50% response], HR： 3.978, 95% CI： 1.278-12.387, P = 0.017）. In conclusion, TTN of PSA remains an important prognostic marker in predicting therapeutic outcome in Chinese population who receive chemotherapy for mCRPC and have 〉50% PSA remission.
文摘The integration of optical images and elevation data is of great importance for 3D-assisted mapping applications. Very high resolution (VHR) satellite images provide ideal geo-data for mapping building information. Since buildings are inherently elevated objects, these images need to be co-registered with their elevation data for reliable building detection results. However, accurate co-registration is extremely difficult for off-nadir VHR images acquired over dense urban areas. Therefore, this research proposes a Disparity-Based Elevation Co-Registration (DECR) method for generating a Line-of-Sight Digital Surface Model (LoS-DSM) to efficiently achieve image-elevation data co-registration with pixel-level accuracy. Relative to the traditional photogrammetric approach, the RMSE value of the derived elevations is found to be less than 2 pixels. The applicability of the DECR method is demonstrated through elevation-based building detection (EBD) in a challenging dense urban area. The quality of the detection result is found to be more than 90%. Additionally, the detected objects were geo-referenced successfully to their correct ground locations to allow direct integration with other maps. In comparison to the original LoS-DSM development algorithm, the DECR algorithm is more efficient by reducing the calculation steps, preserving the co-registration accuracy, and minimizing the need for elevation normalization in dense urban areas.
基金the Shandong Provincial Natural Science Foundation(No.ZR2020MD097)the National Key Research and Development Program of China(No.2016YFC1401004)the National Natural Science Foundation of China(No.62031005)。
文摘The baseline roll and length errors for wide-swath altimeters are major error sources in sea surface measurements that exhibit strong spatial characteristics in the cross-track direction.These errors can be identified and estimated in accordance with height differences at crossover points generated with nadir altimeters after excluding the interference from other error sources.Most of the wide-swath altimeter baseline estimation methods considered only the roll error in previous studies.A numerical simulation was conducted in this study using nadir altimeters to estimate the roll and length errors simultaneously to provide a selectable scheme for baseline error estimation and correction for future wide-swath altimeters.Results based on the parameters of the surface water and ocean topography mission and Sentinel-3A show that the correlation coefficient of the roll error between the estimated and simulated values is 0.89,while the correlation coefficient of the length error is 0.85.The sea surface height root mean square error(RMSE)can be reduced from 12.18 cm to 6.45 cm based on the two estimated results.The estimation effect can be increased by using multiple nadir altimeters to form an observation constellation.The numerical simulation of the five nadir altimeter constellation shows that the correlation coefficients of the roll and length errors would increase to 0.97,which reduces the sea surface height RMSE to 2.88 cm.In addition,the stability of this method is indicated in simulation experiments,which introduce different degrees of sea state errors.
基金supported in part by the National Natural Science Foundation of China(No.52177093)in part by the Scientific&technical project of China Electric Power Planning&Engineering Institute(K202317).
文摘Cross-regional high voltage direct current(HVDC)systems bring remarkable renewable power injections to the receiver side of power grids.However,HVDC failures result in large disturbances to receivers and cause critical frequency security problems.High renewable energy penetration also reduces the system inertia and damping coefficients.Thus,some nodal frequency nadirs may be much lower than those calculated by the center-of-inertia(COI)and may trigger low-frequency protection.Energy storage is a promising solution for frequency-related problems.In this study,we build an energy storage planning model considering both COI and nodal frequency security constraints.The energy storage capacities and locations are determined in the planning scheme based on year-round operations.First,we carry out a year-round COI-frequency-constrained unit commitment to obtain comprehensive operation modes.Next,we propose a hybrid data-model driven approach to generate nodal frequency security constraints for extensive operation modes effectively.Finally,we achieve optimal energy storage planning with both COI and nodal frequency constraints.Case studies on a modified RTS-79 test system and a 1089-bus power system in practical in Jiangsu,China,verify the effectiveness of the proposed methods.
文摘新型电力系统的频率动态过程受到新能源机组故障穿越行为的显著影响,目前只能通过机电暂态仿真进行精准的暂态频率安全评估,在线应用困难。为此,该文提出一种基于关键准稳态计算的暂态频率安全定量评估方法,通过直接计算故障过程中的若干个关键准稳态断面从而有效判断各新能源机组运行状态,进而实现暂态过程中频率安全指标的准确快速计算。具体而言,首先提出一种故障过程中关键准稳态计算方法,并据此评估系统最大频率变化率。其次,通过引入系统频率变量,提出一种直接计算故障后稳态频率的通用方法。最后,结合新能源机组各状态下的功率缺额,建立了基于关键准稳态的平均系统频率(average system frequency based on quasi-steady-state,QSS-ASF)模型,利用该模型仿真能够快速预测出故障发生后的频率最低点。仿真结果表明,所提方法在不同扰动及电源结构下均可准确判断新能源机组状态,各项频率安全指标评估误差均低于2%,兼具准确性与高效性。
文摘电网受扰后频率最低点预测对新型电力系统的频率安全评估非常重要,而目前已有频率动态分析模型较难快速、准确、灵活地预测电网受扰后频率最低点,其中同步发电机调速系统的低阶通用建模以及新能源接入的影响建模是主要挑战。首先提出了充分考虑频率响应特性的发电机调速系统低阶通用模型,结合新能源场站的通用频率响应模型,建立了新能源接入电网的通用平均系统频率(generic average system frequency,G-ASF)模型,在保证准确度的同时有效降低了模型阶数。然后,基于G-ASF模型直接预测电网在给定功率损失下的频率最低点。最后,在IEEE 3机9节点系统以及含新能源的IEEE 10机39节点系统中进行了仿真,结果表明提出的模型和方法在不同扰动或不同系统结构下均能准确预测频率最低点,且能够用于快速计算频率安全约束下的新能源渗透率极限值,验证了模型的准确性和通用性。
