In the traditional environment, the factors for considering the location of the waste transfer station and the landfill are relatively fixed, and the scale of the problem is small. But in Internet of Things(IoT) envir...In the traditional environment, the factors for considering the location of the waste transfer station and the landfill are relatively fixed, and the scale of the problem is small. But in Internet of Things(IoT) environment, the waste storage in the household waste can be monitored in real time, the environmental data can be collected by means of emerging information technology, and the residents are more sensitive to the environmental pollution of the waste. Under such conditions, the method for location of traditional waste disposal facilities needs to be redeveloped to obtain a waste transfer station and landfill site that are suitable for the IoT environment. For this reason, a two-objective integer programming model is designed. The two objectives are lowest cost and minimum impact of waste on residents. The expectations of city managers and residents are considered into the modeling. Through the simulation experiments on different scale problems, the integration method for integer programming model and simulation system is verified to solve the location of waste transfer stations in IoT environment.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
In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model ...In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model for risk management of cascade hydropower stations in the medium-term electricity market is presented. The objective function is profit maximization of cascade hydropower stations. In order to avoid the risks of price and inflow uncertainties, two different risk-aversion constraints: a minimum profit constraint and a minimum conditional value-at-risk, are introduced in the model. In addition, the model takes into account technology constraints of the generating units, which includes reservoir flow balance, reservoir capacity limits, water discharge constraints, etc. The model is formulated as a mixed integer nonlinear programming problem. Because the search space of the solution is very large, a genetic algorithm is used to deal with the problem.展开更多
对已有梯级水电站进行融合改造,增建抽水蓄能机组形成梯级混合式抽水蓄能电站,是加快抽水蓄能发展的有效途径之一。梯级混合式抽水蓄能电站相较于常规梯级电站,新增具备抽水运行工况,相较于传统抽水蓄能电站,又具有更加复杂梯级水力联系...对已有梯级水电站进行融合改造,增建抽水蓄能机组形成梯级混合式抽水蓄能电站,是加快抽水蓄能发展的有效途径之一。梯级混合式抽水蓄能电站相较于常规梯级电站,新增具备抽水运行工况,相较于传统抽水蓄能电站,又具有更加复杂梯级水力联系,灵活的运行模式需要更为精细化的调度建模方法。为探索其典型调峰运行模式,提出了梯级混合式抽水蓄能电站短期调峰优化模型。该模型以电网剩余负荷峰谷差最小为目标,以机组为最小调度单元,针对不同类型机组的抽-发运行工况采用差异化建模。在模型求解方面,通过线性转换方法将原有非线性模型转化为混合整数线性规划(mixed integer linear programming,MILP)模型,然后在JAVA环境中运用CPLEX数学工具进行求解。以西南某梯级水电站为实例的分析结果表明,梯级混合式抽水蓄能电站相较于常规梯级电站电网剩余负荷峰谷差减少4.6%。展开更多
基金Supported by the National Natural Science Foundation of China(71531009).
文摘In the traditional environment, the factors for considering the location of the waste transfer station and the landfill are relatively fixed, and the scale of the problem is small. But in Internet of Things(IoT) environment, the waste storage in the household waste can be monitored in real time, the environmental data can be collected by means of emerging information technology, and the residents are more sensitive to the environmental pollution of the waste. Under such conditions, the method for location of traditional waste disposal facilities needs to be redeveloped to obtain a waste transfer station and landfill site that are suitable for the IoT environment. For this reason, a two-objective integer programming model is designed. The two objectives are lowest cost and minimum impact of waste on residents. The expectations of city managers and residents are considered into the modeling. Through the simulation experiments on different scale problems, the integration method for integer programming model and simulation system is verified to solve the location of waste transfer stations in IoT environment.
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.
基金The National Natural Science Foundation of China (No.50579101)
文摘In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model for risk management of cascade hydropower stations in the medium-term electricity market is presented. The objective function is profit maximization of cascade hydropower stations. In order to avoid the risks of price and inflow uncertainties, two different risk-aversion constraints: a minimum profit constraint and a minimum conditional value-at-risk, are introduced in the model. In addition, the model takes into account technology constraints of the generating units, which includes reservoir flow balance, reservoir capacity limits, water discharge constraints, etc. The model is formulated as a mixed integer nonlinear programming problem. Because the search space of the solution is very large, a genetic algorithm is used to deal with the problem.
文摘对已有梯级水电站进行融合改造,增建抽水蓄能机组形成梯级混合式抽水蓄能电站,是加快抽水蓄能发展的有效途径之一。梯级混合式抽水蓄能电站相较于常规梯级电站,新增具备抽水运行工况,相较于传统抽水蓄能电站,又具有更加复杂梯级水力联系,灵活的运行模式需要更为精细化的调度建模方法。为探索其典型调峰运行模式,提出了梯级混合式抽水蓄能电站短期调峰优化模型。该模型以电网剩余负荷峰谷差最小为目标,以机组为最小调度单元,针对不同类型机组的抽-发运行工况采用差异化建模。在模型求解方面,通过线性转换方法将原有非线性模型转化为混合整数线性规划(mixed integer linear programming,MILP)模型,然后在JAVA环境中运用CPLEX数学工具进行求解。以西南某梯级水电站为实例的分析结果表明,梯级混合式抽水蓄能电站相较于常规梯级电站电网剩余负荷峰谷差减少4.6%。
