Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generati...Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generation, too-large droplet generation, and too-low droplet speed. These challenges reduce the stability and precision of DOD printing, disorder cell arrays, and hence generate further structural errors. In this paper, a multi-objective optimization (MOO) design method for DOD printing parameters through fully connected neural networks (FCNNs) is proposed in order to solve these challenges. The MOO problem comprises two objective functions: to develop the satellite formation model with FCNNs;and to decrease droplet diameter and increase droplet speed. A hybrid multi-subgradient descent bundle method with an adaptive learning rate algorithm (HMSGDBA), which combines the multisubgradient descent bundle (MSGDB) method with Adam algorithm, is introduced in order to search for the Pareto-optimal set for the MOO problem. The superiority of HMSGDBA is demonstrated through comparative studies with the MSGDB method. The experimental results show that a single droplet can be printed stably and the droplet speed can be increased from 0.88 to 2.08 m·s^-1 after optimization with the proposed method. The proposed method can improve both printing precision and stability, and is useful in realizing precise cell arrays and complex biological functions. Furthermore, it can be used to obtain guidelines for the setup of cell-printing experimental platforms.展开更多
园区综合能源系统(Park-level Integrated Energy System,PIES)供能设备多样,能源耦合机制复杂,是典型的复杂能源系统。为实现PIES低碳经济运行并提升风电消纳量以及解决系统因用能结构不合理导致的能源利用效率偏低问题,文中建立了电...园区综合能源系统(Park-level Integrated Energy System,PIES)供能设备多样,能源耦合机制复杂,是典型的复杂能源系统。为实现PIES低碳经济运行并提升风电消纳量以及解决系统因用能结构不合理导致的能源利用效率偏低问题,文中建立了电热需求响应模型优化负荷,并充分考量能量的“质”与“量”,基于热力学第一、第二定律建立了对系统碳排放约束性较强的综合能效模型,并将系统的热负荷根据能源品位进行细化区分,依据热能梯级利用理论,建立了能量耦合设备的数学模型。最后结合系统经济成本目标及系统综合能效目标建立了园区综合能源系统多目标优化调度模型,实现针对系统内各设备出力的调度。算例分析表明,文中提出的优化调度方案能够在提升系统风电消纳率及运行经济性的同时兼顾系统的低碳高效运行。展开更多
针对有服务顺序限制的带时间窗的多需求多目标车辆路径问题(multi-demand and multi-objective vehicle routing problem with time window,MDMOVRPTW),在考虑多种需求由不同车辆按顺序服务等约束条件的同时,构建了最小化配送成本和最...针对有服务顺序限制的带时间窗的多需求多目标车辆路径问题(multi-demand and multi-objective vehicle routing problem with time window,MDMOVRPTW),在考虑多种需求由不同车辆按顺序服务等约束条件的同时,构建了最小化配送成本和最大化客户满意度的多目标模型。根据模型的特点设计了改进的哈里斯鹰优化(improved Harris hawks optimization,IHHO)算法,随机地将种群中部分支配解作为父代解,用临时组合算子和4种交叉算子搜索新解。最后,算例测试结果表明,相较于传统的哈里斯鹰优化算法,IHHO算法的求解性能得到了有效改善,各操作算子中交叉算子2的求解效果最好。将IHHO算法用于实例中,求解结果得到了改善,充分验证了IHHO算法的有效性。展开更多
Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was est...Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the optimal adjustment scope for cropland area ranges from 27 976.75 ha to 31 029.08 ha,and the current area is less than the lower limit of the scope; 2) the optimal adjustment scope for garden land area ranges from 4 736.49 ha to 12 967.11 ha,and the current area is less than the lower limit; 3) the optimal adjustment scope for construction land ranges from 7 761.95 ha to 10 393.18 ha,and the current area is greater than the upper limit; 4) the optimal adjustment scope for industry and mining land ranges from 557.29 ha to 693.54 ha,and the current area exceeds the upper limit; and 5) the areas of forest land,grassland and other agricultural land are within the optimal adjustment scope. In order to maximize comprehensive benefit with the limited resources and the demand of sustainable development,the areas of cropland and garden land are supposed to be expanded properly,while the construction land should be controlled and reduced gradually,and the forest land and other agricultural land can be maintained at the current level in short period.展开更多
文摘Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generation, too-large droplet generation, and too-low droplet speed. These challenges reduce the stability and precision of DOD printing, disorder cell arrays, and hence generate further structural errors. In this paper, a multi-objective optimization (MOO) design method for DOD printing parameters through fully connected neural networks (FCNNs) is proposed in order to solve these challenges. The MOO problem comprises two objective functions: to develop the satellite formation model with FCNNs;and to decrease droplet diameter and increase droplet speed. A hybrid multi-subgradient descent bundle method with an adaptive learning rate algorithm (HMSGDBA), which combines the multisubgradient descent bundle (MSGDB) method with Adam algorithm, is introduced in order to search for the Pareto-optimal set for the MOO problem. The superiority of HMSGDBA is demonstrated through comparative studies with the MSGDB method. The experimental results show that a single droplet can be printed stably and the droplet speed can be increased from 0.88 to 2.08 m·s^-1 after optimization with the proposed method. The proposed method can improve both printing precision and stability, and is useful in realizing precise cell arrays and complex biological functions. Furthermore, it can be used to obtain guidelines for the setup of cell-printing experimental platforms.
文摘园区综合能源系统(Park-level Integrated Energy System,PIES)供能设备多样,能源耦合机制复杂,是典型的复杂能源系统。为实现PIES低碳经济运行并提升风电消纳量以及解决系统因用能结构不合理导致的能源利用效率偏低问题,文中建立了电热需求响应模型优化负荷,并充分考量能量的“质”与“量”,基于热力学第一、第二定律建立了对系统碳排放约束性较强的综合能效模型,并将系统的热负荷根据能源品位进行细化区分,依据热能梯级利用理论,建立了能量耦合设备的数学模型。最后结合系统经济成本目标及系统综合能效目标建立了园区综合能源系统多目标优化调度模型,实现针对系统内各设备出力的调度。算例分析表明,文中提出的优化调度方案能够在提升系统风电消纳率及运行经济性的同时兼顾系统的低碳高效运行。
文摘针对有服务顺序限制的带时间窗的多需求多目标车辆路径问题(multi-demand and multi-objective vehicle routing problem with time window,MDMOVRPTW),在考虑多种需求由不同车辆按顺序服务等约束条件的同时,构建了最小化配送成本和最大化客户满意度的多目标模型。根据模型的特点设计了改进的哈里斯鹰优化(improved Harris hawks optimization,IHHO)算法,随机地将种群中部分支配解作为父代解,用临时组合算子和4种交叉算子搜索新解。最后,算例测试结果表明,相较于传统的哈里斯鹰优化算法,IHHO算法的求解性能得到了有效改善,各操作算子中交叉算子2的求解效果最好。将IHHO算法用于实例中,求解结果得到了改善,充分验证了IHHO算法的有效性。
基金Under the auspices of National Key Technology R&D Program of China (No. 2006BAB04A08)
文摘Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the optimal adjustment scope for cropland area ranges from 27 976.75 ha to 31 029.08 ha,and the current area is less than the lower limit of the scope; 2) the optimal adjustment scope for garden land area ranges from 4 736.49 ha to 12 967.11 ha,and the current area is less than the lower limit; 3) the optimal adjustment scope for construction land ranges from 7 761.95 ha to 10 393.18 ha,and the current area is greater than the upper limit; 4) the optimal adjustment scope for industry and mining land ranges from 557.29 ha to 693.54 ha,and the current area exceeds the upper limit; and 5) the areas of forest land,grassland and other agricultural land are within the optimal adjustment scope. In order to maximize comprehensive benefit with the limited resources and the demand of sustainable development,the areas of cropland and garden land are supposed to be expanded properly,while the construction land should be controlled and reduced gradually,and the forest land and other agricultural land can be maintained at the current level in short period.
