In the study of complex networks almost all theoretical models have the property of infinite growth, but the size of actual networks is finite. According to statistics from the China Internet IPv4 （Internet Protocol ...In the study of complex networks almost all theoretical models have the property of infinite growth, but the size of actual networks is finite. According to statistics from the China Internet IPv4 （Internet Protocol version 4） addresses, this paper proposes a forecasting model by using S curve （logistic curve）. The growing trend of IPv4 addresses in China is forecasted. There are some reference values for optimizing the distribution of IPv4 address resource and the development of IPv6. Based on the laws of IPv4 growth, that is, the bulk growth and the finitely growing limit, it proposes a finite network model with a bulk growth. The model is said to be an S-curve network. Analysis demonstrates that the analytic method based on uniform distributions （i.e., Barabasi-Albert method） is not suitable for the network. It develops an approximate method to predict the growth dynamics of the individual nodes, and uses this to calculate analytically the degree distribution and the scaling exponents. The analytical result agrees with the simulation well, obeying an approximately power-law form. This method can overcome a shortcoming of Barabasi-Albert method commonly used in current network research.展开更多
Simulated annealing(SA) algorithm is a heuristic algorithm,proposed one approximation algorithm of solving optimization combinatorial problems inspired by objects in the annealing process of heating crunch. The algori...Simulated annealing(SA) algorithm is a heuristic algorithm,proposed one approximation algorithm of solving optimization combinatorial problems inspired by objects in the annealing process of heating crunch. The algorithm is superior to the traditional greedy algorithm,which avoids falling into local optimum and reaches global optimum. There are often some problems to find the shortest path,etc in the logistics and distribution network, and we need optimization for logistics and distribution path in order to achieve the shortest,best,most economical,and so on. The paper uses an example of SA algorithm validation to verify it,and the method is proved to be feasible.展开更多
In this paper, a new topological approach for studying an integer sequence constructed from Logistic mapping is proposed. By evenly segmenting [0,1]?into N non-overlapping subintervals which is marked as , representin...In this paper, a new topological approach for studying an integer sequence constructed from Logistic mapping is proposed. By evenly segmenting [0,1]?into N non-overlapping subintervals which is marked as , representing the nodes identities, a network is constructed for analysis. Wherein the undirected edges symbolize their relation of adjacency in an integer sequence obtained from the Logistic mapping and the top integral function. By observation, we find that nodes’ degree changes with different values of??instead of the initial value—X0, and the degree distribution presents the characteristics of scale free network, presenting power law distribution. The results presented in this paper provide some insight into degree distribution of the network constructed from integer sequence that may help better understanding of the nature of Logistic mapping.展开更多
The increasing integration of photovoltaic generators(PVGs) and the uneven economic development in different regions may cause the unbalanced spatial-temporal distribution of load demands in an urban distribution netw...The increasing integration of photovoltaic generators(PVGs) and the uneven economic development in different regions may cause the unbalanced spatial-temporal distribution of load demands in an urban distribution network(UDN). This may lead to undesired consequences, including PVG curtailment, load shedding, and equipment inefficiency, etc. Global dynamic reconfiguration provides a promising method to solve those challenges. However, the power flow transfer capabilities for different kinds of switches are diverse, and the willingness of distribution system operators(DSOs) to select them is also different. In this paper, we formulate a multi-objective dynamic reconfiguration optimization model suitable for multi-level switching modes to minimize the operation cost, load imbalance, and the PVG curtailment. The multi-level switching includes feeder-level switching, transformer-level switching, and substation-level switching. A novel load balancing index is devised to quantify the global load balancing degree at different levels. Then, a stochastic programming model based on selected scenarios is established to address the uncertainties of PVGs and loads. Afterward, the fuzzy c-means(FCMs) clustering is applied to divide the time periods of reconfiguration. Furthermore, the modified binary particle swarm optimization(BPSO)and Cplex solver are combined to solve the proposed mixed-integer second-order cone programming(MISOCP) model. Numerical results based on the 148-node and 297-node systems are obtained to validate the effectiveness of the proposed method.展开更多
为了在发生突发性公共事件实现应急物资统一供应管理体系下的物资分级与协同配送,根据具体的突发状况,将应急物资的重要程度分为若干级别,按照优先调配重要物资的原则,建立了多个仓库之间物资分级协同配送的数学模型,能在整个区域内对...为了在发生突发性公共事件实现应急物资统一供应管理体系下的物资分级与协同配送,根据具体的突发状况,将应急物资的重要程度分为若干级别,按照优先调配重要物资的原则,建立了多个仓库之间物资分级协同配送的数学模型,能在整个区域内对运输车辆及各类应急物资进行整合优化。该模型以总配送时间最短为优化目标,将协同配送与时序决策结合起来,将所有车辆在各仓库与需求点之间的配送过程,看作多智能体协作的时序决策过程,降低了多智能主体多任务指派问题的计算复杂程度,使得在大规模问题的情况下,针对时序决策模型的算法依然能够适用。并且,在改进LSTM(Long Short Term Mermory)网络实现输入与输出维度可变的基础上,结合遗传算法(Genetic Algorithm,GA)的理论框架,设计了针对该问题的LSTM-GA算法,并进行了算例模拟,发现LSTM-GA算法的收敛速度与稳定性较单一算法得以提升。结果表明:LSTM-GA算法能够实现LSTM网络接收和输出信息维度的可变性,是一种研究应急物资分级协同配送的有效方法。展开更多
In a context where express delivery service is indispensable in urban production and life in China,urban express joint distribution will help reduce the negative impact of logistics activities on urban traffic and env...In a context where express delivery service is indispensable in urban production and life in China,urban express joint distribution will help reduce the negative impact of logistics activities on urban traffic and environment,and eventually promote the coordinated development of the express delivery industry and the city.This paper summarizes the background of urban express joint distribution based on its four driving forces:saving resources,green development,traffic avoidance,and public service.Then it establishes a network structure model of urban express joint distribution based on systems thinking,elaborates the functional orientations of the four layers in the model–the distribution layer,the feeder transport layer,the terminal station layer,and the collection and delivery layer,and discusses the implementation ideas of joint distribution at all layers.Finally,it puts forward four suggestions for promoting the joint distribution:improving inter-departmental coordination mechanism,maintaining a diversified distribution pattern,promoting in-depth cooperation among companies,and practicing a high-tech development path.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 70871082)the Shanghai Leading Academic Discipline Project (Grant No. S30504)
文摘In the study of complex networks almost all theoretical models have the property of infinite growth, but the size of actual networks is finite. According to statistics from the China Internet IPv4 （Internet Protocol version 4） addresses, this paper proposes a forecasting model by using S curve （logistic curve）. The growing trend of IPv4 addresses in China is forecasted. There are some reference values for optimizing the distribution of IPv4 address resource and the development of IPv6. Based on the laws of IPv4 growth, that is, the bulk growth and the finitely growing limit, it proposes a finite network model with a bulk growth. The model is said to be an S-curve network. Analysis demonstrates that the analytic method based on uniform distributions （i.e., Barabasi-Albert method） is not suitable for the network. It develops an approximate method to predict the growth dynamics of the individual nodes, and uses this to calculate analytically the degree distribution and the scaling exponents. The analytical result agrees with the simulation well, obeying an approximately power-law form. This method can overcome a shortcoming of Barabasi-Albert method commonly used in current network research.
基金National Natural Science Foundation of China(No.50574037)Henan Soft Science Research Project(No.102400410033No.102400410032)
文摘Simulated annealing(SA) algorithm is a heuristic algorithm,proposed one approximation algorithm of solving optimization combinatorial problems inspired by objects in the annealing process of heating crunch. The algorithm is superior to the traditional greedy algorithm,which avoids falling into local optimum and reaches global optimum. There are often some problems to find the shortest path,etc in the logistics and distribution network, and we need optimization for logistics and distribution path in order to achieve the shortest,best,most economical,and so on. The paper uses an example of SA algorithm validation to verify it,and the method is proved to be feasible.
文摘In this paper, a new topological approach for studying an integer sequence constructed from Logistic mapping is proposed. By evenly segmenting [0,1]?into N non-overlapping subintervals which is marked as , representing the nodes identities, a network is constructed for analysis. Wherein the undirected edges symbolize their relation of adjacency in an integer sequence obtained from the Logistic mapping and the top integral function. By observation, we find that nodes’ degree changes with different values of??instead of the initial value—X0, and the degree distribution presents the characteristics of scale free network, presenting power law distribution. The results presented in this paper provide some insight into degree distribution of the network constructed from integer sequence that may help better understanding of the nature of Logistic mapping.
基金supported by the National Key R&D Program of China (No.2019YFE0123600)National Natural Science Foundation of China (No.52077146)Young Elite Scientists Sponsorship Program by CSEE (No.CESS-YESS-2019027)。
文摘The increasing integration of photovoltaic generators(PVGs) and the uneven economic development in different regions may cause the unbalanced spatial-temporal distribution of load demands in an urban distribution network(UDN). This may lead to undesired consequences, including PVG curtailment, load shedding, and equipment inefficiency, etc. Global dynamic reconfiguration provides a promising method to solve those challenges. However, the power flow transfer capabilities for different kinds of switches are diverse, and the willingness of distribution system operators(DSOs) to select them is also different. In this paper, we formulate a multi-objective dynamic reconfiguration optimization model suitable for multi-level switching modes to minimize the operation cost, load imbalance, and the PVG curtailment. The multi-level switching includes feeder-level switching, transformer-level switching, and substation-level switching. A novel load balancing index is devised to quantify the global load balancing degree at different levels. Then, a stochastic programming model based on selected scenarios is established to address the uncertainties of PVGs and loads. Afterward, the fuzzy c-means(FCMs) clustering is applied to divide the time periods of reconfiguration. Furthermore, the modified binary particle swarm optimization(BPSO)and Cplex solver are combined to solve the proposed mixed-integer second-order cone programming(MISOCP) model. Numerical results based on the 148-node and 297-node systems are obtained to validate the effectiveness of the proposed method.
文摘为了在发生突发性公共事件实现应急物资统一供应管理体系下的物资分级与协同配送,根据具体的突发状况,将应急物资的重要程度分为若干级别,按照优先调配重要物资的原则,建立了多个仓库之间物资分级协同配送的数学模型,能在整个区域内对运输车辆及各类应急物资进行整合优化。该模型以总配送时间最短为优化目标,将协同配送与时序决策结合起来,将所有车辆在各仓库与需求点之间的配送过程,看作多智能体协作的时序决策过程,降低了多智能主体多任务指派问题的计算复杂程度,使得在大规模问题的情况下,针对时序决策模型的算法依然能够适用。并且,在改进LSTM(Long Short Term Mermory)网络实现输入与输出维度可变的基础上,结合遗传算法(Genetic Algorithm,GA)的理论框架,设计了针对该问题的LSTM-GA算法,并进行了算例模拟,发现LSTM-GA算法的收敛速度与稳定性较单一算法得以提升。结果表明:LSTM-GA算法能够实现LSTM网络接收和输出信息维度的可变性,是一种研究应急物资分级协同配送的有效方法。
基金supported by the fund program of the National Natural Science Foundation of China titled Research on the Organization and Evolution of E-Commerce Joint Distribution Service Network Based on Social Channels(71502002)the Soft Science Project of Anhui Province titled Research on Strategies for Developing an E-Commerce Joint Distribution System in Anhui Province(1607a O202059)。
文摘In a context where express delivery service is indispensable in urban production and life in China,urban express joint distribution will help reduce the negative impact of logistics activities on urban traffic and environment,and eventually promote the coordinated development of the express delivery industry and the city.This paper summarizes the background of urban express joint distribution based on its four driving forces:saving resources,green development,traffic avoidance,and public service.Then it establishes a network structure model of urban express joint distribution based on systems thinking,elaborates the functional orientations of the four layers in the model–the distribution layer,the feeder transport layer,the terminal station layer,and the collection and delivery layer,and discusses the implementation ideas of joint distribution at all layers.Finally,it puts forward four suggestions for promoting the joint distribution:improving inter-departmental coordination mechanism,maintaining a diversified distribution pattern,promoting in-depth cooperation among companies,and practicing a high-tech development path.
