The hydro unit economic load dispatch （ELD） is of great importance in energy conservation and emission reduction. Dynamic programming （DP） and genetic algorithm （GA） are two representative algorithms for solving...The hydro unit economic load dispatch （ELD） is of great importance in energy conservation and emission reduction. Dynamic programming （DP） and genetic algorithm （GA） are two representative algorithms for solving ELD problems. The goal of this study was to examine the performance of DP and GA while they were applied to ELD. We established numerical experiments to conduct performance comparisons between DP and GA with two given schemes. The schemes included comparing the CPU time of the algorithms when they had the same solution quality, and comparing the solution quality when they had the same CPU time. The numerical experiments were applied to the Three Gorges Reservoir in China, which is equipped with 26 hydro generation units. We found the relation between the performance of algorithms and the number of units through experiments. Results show that GA is adept at searching for optimal solutions in low-dimensional cases. In some cases, such as with a number of units of less than 10, GA＇s performance is superior to that of a coarse-grid DP. However, GA loses its superiority in high-dimensional cases. DP is powerful in obtaining stable and high-quality solutions. Its performance can be maintained even while searching over a large solution space. Nevertheless, due to its exhaustive enumerating nature, it costs excess time in low-dimensional cases.展开更多
In the framework of liberalized deregulated electricity market, dynamic competitive environment exists between wholesale and retail dealers for energy supplying and management. Smart Grids topology in form of energy m...In the framework of liberalized deregulated electricity market, dynamic competitive environment exists between wholesale and retail dealers for energy supplying and management. Smart Grids topology in form of energy management has forced power supplying agencies to become globally competitive. Demand Response (DR) Programs in context with smart energy network have influenced prosumers and consumers towards it. In this paper Fair Emergency Demand Response Program (FEDRP) is integrated for managing the loads intelligently by using the platform of Smart Grids for Residential Setup. The paper also provides detailed modelling and analysis of respective demands of residential consumers in relation with economic load model for FEDRP. Due to increased customer’s partaking in this program the load on the utility is reduced and managed intelligently during emergency hours by providing fair and attractive incentives to residential clients, thus shifting peak load to off peak hours. The numerical and graphical results are matched for intelligent load management scenario.展开更多
AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection wer...AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection were enrolled in this study.PD-1 expression in total T cells was detected by flow cytometry.Levels of total CD8+T cell responses and proliferation in relation to PD-1 expression levels were analyzed with intracellular staining and PD-1/ PD-L1 blockage. RESULTS:The PD-1 expression in T cells was dynamically changed during the natural course of chronic HBV infection,did not significantly increase in the immune tolerance phase,and returned to normal in the inactive virus carrier stage.Blockage of the PD-1/PD-L1 pathway could not affect the T-cell response in the immune tolerance and inactive virus carrier stages of chronic HBV infection.However,it could significantly restore the T-cell response in the immune clearance stage of chronic HBV infection.Furthermore,the PD-1 expression level in T cells was associated with the alanine aminotransferase level during the immune clearance stage of chronic HBV infection. CONCLUSION:The PD-l/PD-L1 pathway plays a different role in T-cell response during the natural course of chronic HBV infection.展开更多
This research studies short-term electricity load prediction with a large-scalelinear programming support vector regression (LP-SVR) model. The LP-SVR is compared with other three non-linear regression models: Collob...This research studies short-term electricity load prediction with a large-scalelinear programming support vector regression (LP-SVR) model. The LP-SVR is compared with other three non-linear regression models: Collobert’s SVR, Feed-Forward Neural Networks (FFNN), and Bagged Regression Trees (BRT). The four models are trained to predict hourly day-ahead loads given temperature predictions, holiday information and historical loads. The models are trained on-hourly data from the New England Power Pool (NEPOOL) region from 2004 to 2007 and tested on out-of-sample data from 2008. Experimental results indicate that the proposed LP-SVR method gives the smallest error when compared against the other approaches. The LP-SVR shows a mean absolute percent error of 1.58% while the FFNN approach has a 1.61%. Similarly, the FFNN method shows a 330 MWh (Megawatts-hour) mean absolute error, whereas the LP-SVR approach gives a 238 MWh mean absolute error. This is a significant difference in terms of the extra power that would need to be produced if FFNN was used. The proposed LP-SVR model can be utilized for predicting power loads to a very low error, and it is comparable to FFNN and over-performs other state of the art methods such as: Bagged Regression Trees, and Large-Scale SVRs.展开更多
The present paper aims at modeling suspended sediment load(SSL) using heuristic data driven methodologies, e.g. Gene Expression Programming(GEP) and Support Vector Machine(SVM) in three successive hydrometric stations...The present paper aims at modeling suspended sediment load(SSL) using heuristic data driven methodologies, e.g. Gene Expression Programming(GEP) and Support Vector Machine(SVM) in three successive hydrometric stations of Housatonic River in U.S. The simulations were carried out through local and cross-station data management scenarios to investigate the interrelations between the SSL values of upstream/downstream stations. The available scenarios were applied to predict SSL values using GEP to obtain the best models. Then, the best models were predicted by SVM approach and the obtained results were compared with those of GEP. The comparison of the results revealed that the SVM technique is more capable than the GEP for modeling the SSL through the both local and cross-station data management strategies. Besides, local application seems to be better than cross-station application for modeling SSL. Nevertheless, the cross-station application demonstrated to be a valid methodology for simulating SSL, which would be of interest for the stations with lack of observational data. Also, the prediction capability of conventional Sediment Rating Curve(SRC) method was compared with those of GEPand SVM techniques. The obtained results revealed the superiority of GEP and SVM-based models over the traditional SRC technique in the studied stations.展开更多
为提高微电网的供电可靠率和能源利用率,提出一种计及分时电价的日前经济优化调度方法。首先建立光伏、储能(energy storage system,ESS)、电动汽车(electric vehicles,EV)等主体的功率或能量模型,然后分别采用光伏功率模型及双向长短...为提高微电网的供电可靠率和能源利用率,提出一种计及分时电价的日前经济优化调度方法。首先建立光伏、储能(energy storage system,ESS)、电动汽车(electric vehicles,EV)等主体的功率或能量模型,然后分别采用光伏功率模型及双向长短期记忆(bidirectional long short term memory,Bi-LSTM)模型预测日内光伏及常规负荷功率。结合EV的柔性负荷特性,以最小化系统运维总成本(包括设备运维成本、外网取电成本、储能电池衰减成本等)及EV充电成本建立目标函数。考虑优化问题的多目标、高维特性,选用线性规划求解器求解目标函数。最后选取含光-储-充的某工业园区微电网2021年全年的历史运行数据,首先测试了本文提出的常规负荷及光伏功率预测模型,进而根据光伏出力与常规负荷的匹配差异,选取4种典型日场景测试本文提出的调控算法。结果证明所提功率预测模型及经济调度算法的有效性。展开更多
作为海上风力发电机运维的关键环节,吊装工程中风载荷的研究至关重要。其中,三叶式吊装作为常用吊装方式,其工作过程中的风载荷特性值得深入探究。为更好地完成海上吊装工作,规避风险,本文建立了叶轮吊装模型,对施工过程中吊装系统各个...作为海上风力发电机运维的关键环节,吊装工程中风载荷的研究至关重要。其中,三叶式吊装作为常用吊装方式,其工作过程中的风载荷特性值得深入探究。为更好地完成海上吊装工作,规避风险,本文建立了叶轮吊装模型,对施工过程中吊装系统各个阶段所受风载荷进行理论分析推导,包括水平提吊阶段、叶轮翻转阶段和竖直提吊阶段。基于翼型理论,以美国国家可再生能源实验室(National Renewable Energy Laboratory,NREL)5 MW风机为例,编写程序计算风机三叶式吊装过程中所受风载荷,分析了迎风角度、风向、高度对吊装过程风载荷的影响,评估其安全性和可靠性,为实际工程提供参考和指导。展开更多
基金supported by the National Basic Research Program of China(973 Program,Grant No.2013CB036406)the National Natural Science Foundation of China(Grant No.51179044)the Research Innovation Program for College Graduates in Jiangsu Province of China(Grant No.CXZZ12-0242)
文摘The hydro unit economic load dispatch （ELD） is of great importance in energy conservation and emission reduction. Dynamic programming （DP） and genetic algorithm （GA） are two representative algorithms for solving ELD problems. The goal of this study was to examine the performance of DP and GA while they were applied to ELD. We established numerical experiments to conduct performance comparisons between DP and GA with two given schemes. The schemes included comparing the CPU time of the algorithms when they had the same solution quality, and comparing the solution quality when they had the same CPU time. The numerical experiments were applied to the Three Gorges Reservoir in China, which is equipped with 26 hydro generation units. We found the relation between the performance of algorithms and the number of units through experiments. Results show that GA is adept at searching for optimal solutions in low-dimensional cases. In some cases, such as with a number of units of less than 10, GA＇s performance is superior to that of a coarse-grid DP. However, GA loses its superiority in high-dimensional cases. DP is powerful in obtaining stable and high-quality solutions. Its performance can be maintained even while searching over a large solution space. Nevertheless, due to its exhaustive enumerating nature, it costs excess time in low-dimensional cases.
文摘In the framework of liberalized deregulated electricity market, dynamic competitive environment exists between wholesale and retail dealers for energy supplying and management. Smart Grids topology in form of energy management has forced power supplying agencies to become globally competitive. Demand Response (DR) Programs in context with smart energy network have influenced prosumers and consumers towards it. In this paper Fair Emergency Demand Response Program (FEDRP) is integrated for managing the loads intelligently by using the platform of Smart Grids for Residential Setup. The paper also provides detailed modelling and analysis of respective demands of residential consumers in relation with economic load model for FEDRP. Due to increased customer’s partaking in this program the load on the utility is reduced and managed intelligently during emergency hours by providing fair and attractive incentives to residential clients, thus shifting peak load to off peak hours. The numerical and graphical results are matched for intelligent load management scenario.
基金Supported by Grants from the"Yucai"Research Program of Changhai Hospital
文摘AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection were enrolled in this study.PD-1 expression in total T cells was detected by flow cytometry.Levels of total CD8+T cell responses and proliferation in relation to PD-1 expression levels were analyzed with intracellular staining and PD-1/ PD-L1 blockage. RESULTS:The PD-1 expression in T cells was dynamically changed during the natural course of chronic HBV infection,did not significantly increase in the immune tolerance phase,and returned to normal in the inactive virus carrier stage.Blockage of the PD-1/PD-L1 pathway could not affect the T-cell response in the immune tolerance and inactive virus carrier stages of chronic HBV infection.However,it could significantly restore the T-cell response in the immune clearance stage of chronic HBV infection.Furthermore,the PD-1 expression level in T cells was associated with the alanine aminotransferase level during the immune clearance stage of chronic HBV infection. CONCLUSION:The PD-l/PD-L1 pathway plays a different role in T-cell response during the natural course of chronic HBV infection.
文摘This research studies short-term electricity load prediction with a large-scalelinear programming support vector regression (LP-SVR) model. The LP-SVR is compared with other three non-linear regression models: Collobert’s SVR, Feed-Forward Neural Networks (FFNN), and Bagged Regression Trees (BRT). The four models are trained to predict hourly day-ahead loads given temperature predictions, holiday information and historical loads. The models are trained on-hourly data from the New England Power Pool (NEPOOL) region from 2004 to 2007 and tested on out-of-sample data from 2008. Experimental results indicate that the proposed LP-SVR method gives the smallest error when compared against the other approaches. The LP-SVR shows a mean absolute percent error of 1.58% while the FFNN approach has a 1.61%. Similarly, the FFNN method shows a 330 MWh (Megawatts-hour) mean absolute error, whereas the LP-SVR approach gives a 238 MWh mean absolute error. This is a significant difference in terms of the extra power that would need to be produced if FFNN was used. The proposed LP-SVR model can be utilized for predicting power loads to a very low error, and it is comparable to FFNN and over-performs other state of the art methods such as: Bagged Regression Trees, and Large-Scale SVRs.
文摘The present paper aims at modeling suspended sediment load(SSL) using heuristic data driven methodologies, e.g. Gene Expression Programming(GEP) and Support Vector Machine(SVM) in three successive hydrometric stations of Housatonic River in U.S. The simulations were carried out through local and cross-station data management scenarios to investigate the interrelations between the SSL values of upstream/downstream stations. The available scenarios were applied to predict SSL values using GEP to obtain the best models. Then, the best models were predicted by SVM approach and the obtained results were compared with those of GEP. The comparison of the results revealed that the SVM technique is more capable than the GEP for modeling the SSL through the both local and cross-station data management strategies. Besides, local application seems to be better than cross-station application for modeling SSL. Nevertheless, the cross-station application demonstrated to be a valid methodology for simulating SSL, which would be of interest for the stations with lack of observational data. Also, the prediction capability of conventional Sediment Rating Curve(SRC) method was compared with those of GEPand SVM techniques. The obtained results revealed the superiority of GEP and SVM-based models over the traditional SRC technique in the studied stations.
文摘为提高微电网的供电可靠率和能源利用率,提出一种计及分时电价的日前经济优化调度方法。首先建立光伏、储能(energy storage system,ESS)、电动汽车(electric vehicles,EV)等主体的功率或能量模型,然后分别采用光伏功率模型及双向长短期记忆(bidirectional long short term memory,Bi-LSTM)模型预测日内光伏及常规负荷功率。结合EV的柔性负荷特性,以最小化系统运维总成本(包括设备运维成本、外网取电成本、储能电池衰减成本等)及EV充电成本建立目标函数。考虑优化问题的多目标、高维特性,选用线性规划求解器求解目标函数。最后选取含光-储-充的某工业园区微电网2021年全年的历史运行数据,首先测试了本文提出的常规负荷及光伏功率预测模型,进而根据光伏出力与常规负荷的匹配差异,选取4种典型日场景测试本文提出的调控算法。结果证明所提功率预测模型及经济调度算法的有效性。
基金浙江省“尖兵”“领雁”研发攻关计划(2024C01058)浙江省“十四五”第二批本科省级教学改革备案项目(JGBA2024014)+2 种基金2025年01月批次教育部产学合作协同育人项目(2501270945)2024年度浙江大学本科“AI赋能”示范课程建设项目(24)浙江大学第一批AI For Education系列实证教学研究项目(202402)。
文摘作为海上风力发电机运维的关键环节,吊装工程中风载荷的研究至关重要。其中,三叶式吊装作为常用吊装方式,其工作过程中的风载荷特性值得深入探究。为更好地完成海上吊装工作,规避风险,本文建立了叶轮吊装模型,对施工过程中吊装系统各个阶段所受风载荷进行理论分析推导,包括水平提吊阶段、叶轮翻转阶段和竖直提吊阶段。基于翼型理论,以美国国家可再生能源实验室(National Renewable Energy Laboratory,NREL)5 MW风机为例,编写程序计算风机三叶式吊装过程中所受风载荷,分析了迎风角度、风向、高度对吊装过程风载荷的影响,评估其安全性和可靠性,为实际工程提供参考和指导。
