针对当前用户侧用电设备非侵入式辨识中负荷边沿检测方法准确率不高的问题,该文在研究阈值检测算法（threshold detection algorithm,TDA）、暂态能量启动算法（transient energy to start the algorithm,TEA）、微分算子（method of di...针对当前用户侧用电设备非侵入式辨识中负荷边沿检测方法准确率不高的问题,该文在研究阈值检测算法（threshold detection algorithm,TDA）、暂态能量启动算法（transient energy to start the algorithm,TEA）、微分算子（method of differential algorithm,MDA）以及拟合方法的基础上,提出一种基于高斯滤波器和工业检测累加求和（cumulative sum,CUSUM）算法的边沿检测方法,解决传统算法考虑因素单一、精度不高等问题。该方法采用自适应高斯滤波器能有效过滤噪声,同时保留突变点信息的特点,通过检测去噪后的突变点波动,提升检测的准确性。结合CUSUM算法对设备状态与工作模式变化检测灵敏的特点,提升设备模态的检测速度和准确性。通过搭建的非侵入式负荷辨识平台,对提出的方法进行仿真和实验验证,显示所提出的方法能有效提高用电设备的检测速度和准确率。展开更多
Drilling and blasting play vital roles in opencast mining. These operations not only affect the cost of production directly but as well and significantly, the overall operational costs. This research was carried out t...Drilling and blasting play vital roles in opencast mining. These operations not only affect the cost of production directly but as well and significantly, the overall operational costs. This research was carried out to find a possible way of optimizing the drilling and blasting operations in an open pit mine of Somair (Société des Mines de l’Air), in the Niger Republic. In order to optimize the drilling operation, the time taken by two drilling machines to accomplish the same task was analyzed statistically. The result indicates that the Down the Hole Hammer Drilling Rig (DMNo406) is more efficient than the Drill Master (DM405). The relative unit consumption of two explosives (Explus and Nitram 9), when used under the same operating conditions, were also considered and the results indicate Explus to be more economical per unit consumption with a range of 0.15 g/t–0.183 g/t, when compared with Nitram 9 with a unit consumption range of 0.19 g/t-0.24 g/t in the study area.展开更多
The assumption widely used in the user equilibrium model for stochastic network was that the probability distributions of the travel time were known explicitly by travelers. However, this distribution may be unavailab...The assumption widely used in the user equilibrium model for stochastic network was that the probability distributions of the travel time were known explicitly by travelers. However, this distribution may be unavailable in reality. By relaxing the restrictive assumption, a robust user equilibrium model based on cumulative prospect theory under distribution-free travel time was presented. In the absence of the cumulative distribution function of the travel time, the exact cumulative prospect value(CPV) for each route cannot be obtained. However, the upper and lower bounds on the CPV can be calculated by probability inequalities.Travelers were assumed to choose the routes with the best worst-case CPVs. The proposed model was formulated as a variational inequality problem and solved via a heuristic solution algorithm. A numerical example was also provided to illustrate the application of the proposed model and the efficiency of the solution algorithm.展开更多
Purpose: Increasing physician awareness of patient exposure to radiation is an important step towards the reduction of potentially harmful effects of radiation. Published studies demonstrated that providing physicians...Purpose: Increasing physician awareness of patient exposure to radiation is an important step towards the reduction of potentially harmful effects of radiation. Published studies demonstrated that providing physicians with feedback regarding their fluoroscopy time leads to a reduction in average fluoroscopy times. The aim of this work was to analyze and publish our medical center data observed during the past year;fluoroscopy time (FT), Dose Area Product (DAP) and cumulative dose (CD) were monitored for radiation protection purposes. Methods: Fluoroscopy time is one of multiple radiation dose indices used in radiation safety auditing. Such auditing is nowadays turning into requirement of patient care safety and quality improvement;as indicated by accreditation bodies both nationally and internationally. All non-cardiac procedures performed outside radiology department by surgeons and interventionists are viewed. FT, DAP and CD are extracted for analysis. Results: a total of 846 cases were studied (643 orthopedic, 99 others, 73 urology, 17 chest, 7 vascular and 4 ERCP cases). Mean FT was 1.3 minutes, mean CD to the patient was 12.98 mGy and the mean DAP was 4.53 Gy/cm2. The longest FT noted was 55 min. The maximum CD was 904 mGy and the maximum DAP was 689 Gy/cm2. Using spearman’s correlation test we found out that there is a significant correlation between FT and DAP (correlation coefficient = 0.615, p. value 0.001). There is a significant correlation between FT and CD (correlation coefficient = 0.628, p. value 0.001). Conclusion: Information about FT that used in each procedure can be used as a tool for patient dose optimization. As we found a significant correlation between DAP as well as CD. Reducing fluoroscopic time (FT) is a radiation protection goal, since it serves the purpose of protection for both the patient and the workers.展开更多
Cotton growth and development is effected by various ecological issues like temperature fluctuations, distribution and quantity of rainfall, relative humidity and winds which are the climate change attributes. A field...Cotton growth and development is effected by various ecological issues like temperature fluctuations, distribution and quantity of rainfall, relative humidity and winds which are the climate change attributes. A field experiment was carried out to find out the response of cotton to weather variables in terms of total variation in yield and quality. The effect of planting times and thermal temperatures (cumulative heat units) on yield of 4 cotton cultivars viz;CIM-600, CIM-616, CIM-622 & CRIS-641 was evaluated. Plants were sown on 6 planting times during the year 2015-2016 and 2016-2017 in an experiment conducted in randomized complete block design having three replications. Cotton cultivars depicted significant variances for number of bolls plant-1, boll weight and seed cotton yield. The cultivar CIM-616 depicted the highest seed cotton yield of 2083.60 kg·ha-1 on interpretation of highest bolls and boll weight. Maximum seed cotton yield was noted in planting time from 1st April to 15th April whereas early and late planting decreases the seed cotton yield on account of less accretion of cumulative heat units. Regression analysis depicted that rise of one unit (15 days) from early to optimal date (15th March to 15th April) enhanced the seed cotton yield by 93.76 kg·ha-1 (y = -93.764x2 + 521.04x + 1364). Delayed planting also reduces the seed cotton yield with the same ratio. It is therefore established that cotton must be cultivated from 1st April to 1st May to harvest good production in this type of climate.展开更多
提出考虑卸载时间的累计等待时间式车辆路径问题(Cumulative Capacitated Vehicle Routing Problem with Unload Time,CCVRPUT)模型,该模型考虑货物在目的地的卸载时间,以所有车辆路径上全部客户累计等待时间之和和所有运输车辆额外运...提出考虑卸载时间的累计等待时间式车辆路径问题(Cumulative Capacitated Vehicle Routing Problem with Unload Time,CCVRPUT)模型,该模型考虑货物在目的地的卸载时间,以所有车辆路径上全部客户累计等待时间之和和所有运输车辆额外运转时间支出两者为优化目标,更符合实际物流需要。针对CCVRPUT的特点,采用灰狼优化算法(Grey Wolf Optimizer,GWO)作为主体,采用实数编码和等分随机键与ROV规则结合的方法进行解码,引入2-Opt局部搜索策略,有效对CCVRPUT进行求解。最后,通过实验证明了所提出模型和算法的有效性。展开更多
The nonlinear operation of metal oxide varistor(MOV)-protected series compensator in transmission lines introduces complications into fault detection approaches. The accuracy of a conventional fault detection schemes ...The nonlinear operation of metal oxide varistor(MOV)-protected series compensator in transmission lines introduces complications into fault detection approaches. The accuracy of a conventional fault detection schemes is adversely affected by continuous change of the system impedance and load current at the point of a series compensation unit. Thus, this study suggests a method for detecting the faulted phase in MOV-protected series-compensated transmission lines. Primarily, the fault feature is identified using the covariance coefficients of the current samples during the fault period and the current samples during the pre-fault period. Furthermore, a convenience fault detection index is established by applying the cumulative sum technique. Extensive validation through different fault circumstances is accomplished, including different fault positions,resistances, and inception times. The experimental results show that the proposed method performs well with high resistance or impedance faults, faults in noisy conditions, and close-in and far-end faults. The proposed method is simple and efficient for faulty phase detection in MOV-protected series-compensated transmission lines.展开更多
In clinical and epidemiologic studies of time to event,the treatment effect is often of direct interest,and the treatment effect is not constant over time.In this paper,the authors propose an estimator for the cumulat...In clinical and epidemiologic studies of time to event,the treatment effect is often of direct interest,and the treatment effect is not constant over time.In this paper,the authors propose an estimator for the cumulative hazard difference under a stratified additive hazards model.The asymptotic properties of the resulting estimator are established,and the finite-sample properties are examined through simulation studies.An application to a liver cirrhosis data set from the Copenhagen Study Group for Liver Diseases is provided.展开更多
文摘针对当前用户侧用电设备非侵入式辨识中负荷边沿检测方法准确率不高的问题,该文在研究阈值检测算法（threshold detection algorithm,TDA）、暂态能量启动算法（transient energy to start the algorithm,TEA）、微分算子（method of differential algorithm,MDA）以及拟合方法的基础上,提出一种基于高斯滤波器和工业检测累加求和（cumulative sum,CUSUM）算法的边沿检测方法,解决传统算法考虑因素单一、精度不高等问题。该方法采用自适应高斯滤波器能有效过滤噪声,同时保留突变点信息的特点,通过检测去噪后的突变点波动,提升检测的准确性。结合CUSUM算法对设备状态与工作模式变化检测灵敏的特点,提升设备模态的检测速度和准确性。通过搭建的非侵入式负荷辨识平台,对提出的方法进行仿真和实验验证,显示所提出的方法能有效提高用电设备的检测速度和准确率。
文摘Drilling and blasting play vital roles in opencast mining. These operations not only affect the cost of production directly but as well and significantly, the overall operational costs. This research was carried out to find a possible way of optimizing the drilling and blasting operations in an open pit mine of Somair (Société des Mines de l’Air), in the Niger Republic. In order to optimize the drilling operation, the time taken by two drilling machines to accomplish the same task was analyzed statistically. The result indicates that the Down the Hole Hammer Drilling Rig (DMNo406) is more efficient than the Drill Master (DM405). The relative unit consumption of two explosives (Explus and Nitram 9), when used under the same operating conditions, were also considered and the results indicate Explus to be more economical per unit consumption with a range of 0.15 g/t–0.183 g/t, when compared with Nitram 9 with a unit consumption range of 0.19 g/t-0.24 g/t in the study area.
基金Project(2012CB725400)supported by the National Basic Research Program of ChinaProjects(71271023,71322102,7121001)supported by the National Natural Science Foundation of China
文摘The assumption widely used in the user equilibrium model for stochastic network was that the probability distributions of the travel time were known explicitly by travelers. However, this distribution may be unavailable in reality. By relaxing the restrictive assumption, a robust user equilibrium model based on cumulative prospect theory under distribution-free travel time was presented. In the absence of the cumulative distribution function of the travel time, the exact cumulative prospect value(CPV) for each route cannot be obtained. However, the upper and lower bounds on the CPV can be calculated by probability inequalities.Travelers were assumed to choose the routes with the best worst-case CPVs. The proposed model was formulated as a variational inequality problem and solved via a heuristic solution algorithm. A numerical example was also provided to illustrate the application of the proposed model and the efficiency of the solution algorithm.
文摘Purpose: Increasing physician awareness of patient exposure to radiation is an important step towards the reduction of potentially harmful effects of radiation. Published studies demonstrated that providing physicians with feedback regarding their fluoroscopy time leads to a reduction in average fluoroscopy times. The aim of this work was to analyze and publish our medical center data observed during the past year;fluoroscopy time (FT), Dose Area Product (DAP) and cumulative dose (CD) were monitored for radiation protection purposes. Methods: Fluoroscopy time is one of multiple radiation dose indices used in radiation safety auditing. Such auditing is nowadays turning into requirement of patient care safety and quality improvement;as indicated by accreditation bodies both nationally and internationally. All non-cardiac procedures performed outside radiology department by surgeons and interventionists are viewed. FT, DAP and CD are extracted for analysis. Results: a total of 846 cases were studied (643 orthopedic, 99 others, 73 urology, 17 chest, 7 vascular and 4 ERCP cases). Mean FT was 1.3 minutes, mean CD to the patient was 12.98 mGy and the mean DAP was 4.53 Gy/cm2. The longest FT noted was 55 min. The maximum CD was 904 mGy and the maximum DAP was 689 Gy/cm2. Using spearman’s correlation test we found out that there is a significant correlation between FT and DAP (correlation coefficient = 0.615, p. value 0.001). There is a significant correlation between FT and CD (correlation coefficient = 0.628, p. value 0.001). Conclusion: Information about FT that used in each procedure can be used as a tool for patient dose optimization. As we found a significant correlation between DAP as well as CD. Reducing fluoroscopic time (FT) is a radiation protection goal, since it serves the purpose of protection for both the patient and the workers.
文摘Cotton growth and development is effected by various ecological issues like temperature fluctuations, distribution and quantity of rainfall, relative humidity and winds which are the climate change attributes. A field experiment was carried out to find out the response of cotton to weather variables in terms of total variation in yield and quality. The effect of planting times and thermal temperatures (cumulative heat units) on yield of 4 cotton cultivars viz;CIM-600, CIM-616, CIM-622 & CRIS-641 was evaluated. Plants were sown on 6 planting times during the year 2015-2016 and 2016-2017 in an experiment conducted in randomized complete block design having three replications. Cotton cultivars depicted significant variances for number of bolls plant-1, boll weight and seed cotton yield. The cultivar CIM-616 depicted the highest seed cotton yield of 2083.60 kg·ha-1 on interpretation of highest bolls and boll weight. Maximum seed cotton yield was noted in planting time from 1st April to 15th April whereas early and late planting decreases the seed cotton yield on account of less accretion of cumulative heat units. Regression analysis depicted that rise of one unit (15 days) from early to optimal date (15th March to 15th April) enhanced the seed cotton yield by 93.76 kg·ha-1 (y = -93.764x2 + 521.04x + 1364). Delayed planting also reduces the seed cotton yield with the same ratio. It is therefore established that cotton must be cultivated from 1st April to 1st May to harvest good production in this type of climate.
文摘提出考虑卸载时间的累计等待时间式车辆路径问题(Cumulative Capacitated Vehicle Routing Problem with Unload Time,CCVRPUT)模型,该模型考虑货物在目的地的卸载时间,以所有车辆路径上全部客户累计等待时间之和和所有运输车辆额外运转时间支出两者为优化目标,更符合实际物流需要。针对CCVRPUT的特点,采用灰狼优化算法(Grey Wolf Optimizer,GWO)作为主体,采用实数编码和等分随机键与ROV规则结合的方法进行解码,引入2-Opt局部搜索策略,有效对CCVRPUT进行求解。最后,通过实验证明了所提出模型和算法的有效性。
基金supported by National Natural Science Foundation of China(No. 51777173)。
文摘The nonlinear operation of metal oxide varistor(MOV)-protected series compensator in transmission lines introduces complications into fault detection approaches. The accuracy of a conventional fault detection schemes is adversely affected by continuous change of the system impedance and load current at the point of a series compensation unit. Thus, this study suggests a method for detecting the faulted phase in MOV-protected series-compensated transmission lines. Primarily, the fault feature is identified using the covariance coefficients of the current samples during the fault period and the current samples during the pre-fault period. Furthermore, a convenience fault detection index is established by applying the cumulative sum technique. Extensive validation through different fault circumstances is accomplished, including different fault positions,resistances, and inception times. The experimental results show that the proposed method performs well with high resistance or impedance faults, faults in noisy conditions, and close-in and far-end faults. The proposed method is simple and efficient for faulty phase detection in MOV-protected series-compensated transmission lines.
基金the National Natural Science Foundation of China under Grant Nos.11671268,11771431 and 11690015the Key Laboratory of RCSDS,CAS under Grant No.2008DP173182。
文摘In clinical and epidemiologic studies of time to event,the treatment effect is often of direct interest,and the treatment effect is not constant over time.In this paper,the authors propose an estimator for the cumulative hazard difference under a stratified additive hazards model.The asymptotic properties of the resulting estimator are established,and the finite-sample properties are examined through simulation studies.An application to a liver cirrhosis data set from the Copenhagen Study Group for Liver Diseases is provided.
