An appropriate spatial structure of a power battery supply network is crucial for the specialization and scale development of key components in new energy vehicles, accelerating the transformation and upgrade of the i...An appropriate spatial structure of a power battery supply network is crucial for the specialization and scale development of key components in new energy vehicles, accelerating the transformation and upgrade of the industry. This paper investigates the cooperative relationships among supply chain enterprises from the perspective of complex networks.Employing methodologies such as the gravity model and Moran's I analysis, it explores the spatial structural characteristics and correlation patterns of the power battery supply network in China and discusses the influencing factors using the quadratic assignment procedure,revealing the mechanisms behind the differences in the spatial distributions of the power battery supply network. The results indicate that the distribution of power battery enterprises is densely concentrated in the eastern and southern regions, whereas the western region has a sparse distribution. The spatial supply network consists of a four-tier linkage system, encompassing 135 prefecture-level cities, with Chongqing, Shanghai, Nanjing, and other cities particularly prominent. Overall, the degree of agglomeration is low, with coastal cities dominating the landscape and inland cities serving as complementary regions. Most areas are characterized as insignificant or low-high regions, and the regional linkage effect of core cities is not pronounced. There is a notable lack of significance and high spatial heterogeneity.Four types of factors—spatial factors, market factors, agglomeration economies, and innovation levels—jointly influence and shape the spatial structure of the power battery supply network.展开更多
Using a modified subgradient extragradient algorithm, this paper proposed a novel approach to solving a supply chain network equilibrium model. The method extends the scope of optimisation and improves the accuracy at...Using a modified subgradient extragradient algorithm, this paper proposed a novel approach to solving a supply chain network equilibrium model. The method extends the scope of optimisation and improves the accuracy at each iteration by incorporating adaptive parameter selection and a more general subgradient projection operator. The advantages of the proposed method are highlighted by the proof of strong convergence presented in the paper. Several concrete examples are given to demonstrate the effectiveness of the algorithm, with comparisons illustrating its superior CPU running time compared to alternative techniques. The practical applicability of the algorithm is also demonstrated by applying it to a realistic supply chain network model.展开更多
The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is d...The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is defined by introducing the probability that a facility may be prone to inactivity based on the analysis of perishable product characteristics.The perishable product SCN design problem is formulated as a 0-1 integer programming model.The objective is to minimize the weighted sum of the operating cost(the fixed plus transportation cost)and the expected failure cost.And then,the perishable product SCN design model is discussed and solved using the genetic algorithm(GA).The results show how to generate the tradeoff curve between the operating costs and the expected failure costs.And these tradeoff curves demonstrate empirically that substantial improvements in reliability are often possible with minimal increase in the operating costs.展开更多
An urban water supply network(WSN)is a crucial lifeline system that helps to maintain the normal functioning of modern society.However,the hydraulic analysis of a significantly damaged WSN that suffers from pipe break...An urban water supply network(WSN)is a crucial lifeline system that helps to maintain the normal functioning of modern society.However,the hydraulic analysis of a significantly damaged WSN that suffers from pipe breaks or leaks remains challenging.In this paper,a probability-based framework is proposed to assess the functionality of WSNs in the aftermath of powerful earthquakes.The serviceability of the WSN is quantified by using a comprehensive index that considers nodal water flow and nodal pressure.This index includes a coefficient that reflects the relative importance of these two parameters.The demand reduction(DR)method,which reduces the water flow of nodes while preventing the negative pressure of nodes,is proposed.The difference between the negative pressure elimination(NPE)method and the DR method is discussed by using the example of a WSN in a medium-sized city in China.The functionality values of the WSN are 0.76 and 0.99 when nodal pressure and nodal demands are used respectively as the index of system serviceability at an intensity level that would pertain to an earthquake considered to occur at a maximum level.When the intensity of ground motion is as high as 0.4 g,the DR method requires fewer samples than the NPE method to obtain accurate results.The NPE method eliminates most of the pipes,which may be unrealistic.展开更多
The serviceability of water supply networks(WSNs)under seismic loads has significant importance for estimating the probable losses and the impact of diminished functionality on affected communities.The innovation pres...The serviceability of water supply networks(WSNs)under seismic loads has significant importance for estimating the probable losses and the impact of diminished functionality on affected communities.The innovation presented in this paper is suggesting a new strategy to evaluate the seismic serviceability of WSNs,utilizing their operational physical mechanism.On one hand,this method can obtain the seismic serviceability of each node as well as entire WSNs.On the other hand,this method can dynamically reflect the propagation of randomness from ground motions to WSNs.First,a finite element model is established to capture the seismic response of buried pipe networks,and a leakage model is suggested to obtain the leakage area of WSNs.Second,the transient flow analysis of WSNs with or without leakage is derived to obtain dynamic water flow and pressure.Third,the seismic serviceability of WSNs is analyzed based on the probability density evolution method(PDEM).Finally,the seismic serviceability of a real WSN in Mianzhu city is assessed to illustrate the method.The case study shows that randomness from the ground motions can obviously affect the leakage state and the probability density of the nodal head during earthquakes.展开更多
Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to sol...Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to solve the altered multi-objective optimization model. The introduction of NSGA-II into water supply network optimal rehabilitation problem solves the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. And the uncertainties brought by using weight coefficients or punish functions in conventional methods are controlled. And also by in-troduction of artificial inducement mutation (AIM) operation, the convergence speed of population is accelerated;this operation not only improves the convergence speed, but also improves the rationality and feasibility of solutions.展开更多
Contract is a common and effective mechanism for supply chain coordination,which has been studied extensively in recent years.For a supply chain network model,contracts can be used to coordinate it because it is too i...Contract is a common and effective mechanism for supply chain coordination,which has been studied extensively in recent years.For a supply chain network model,contracts can be used to coordinate it because it is too ideal to obtain the network equilibrium state in practical market competition.In order to achieve equilibrium,we introduce revenue sharing contract into a supply chain network equilibrium model with random demand in this paper.Then,we investigate the influence on this network equilibrium state from demand disruptions caused by unexpected emergencies.When demand disruptions happen,the supply chain network equilibrium state will be broken and change to a new one,so the decision makers need to adjust the contract parameters to achieve the new coordinated state through bargaining.Finally,a numerical example with a sudden demand increase as a result of emergent event is provided for illustrative purposes.展开更多
The supply chain network with capacity constraints of manufacturers and retailers is considered.The linkage between supply chain network equilibrium and transportation network equilibrium is investigated.By analyzing ...The supply chain network with capacity constraints of manufacturers and retailers is considered.The linkage between supply chain network equilibrium and transportation network equilibrium is investigated.By analyzing the relationships among the manufacturers,retailers and consumers in the supply chain network and their own decisions concerning maximum profits,a combined variational inequality for the supply chain network equilibrium mode is proposed.Then an equivalent supernetwork of the supply chain network is constructed by adding additional links which denote the producing of manufactures and the handling of retailers.By the supernetwork,the supply chain network equilibrium model can be reformulated as a transportation network equilibrium model.Equivalent mathematical programming is,therefore,obtained based on the principle of a Wardrop user equilibrium.The corresponding Lagrange multiplier of the capacity constraints can be explained as the extra cost of marginal production when capacity is exceeded.A numerical example is given to illustrate the rationality of the model and the validity of the results.展开更多
With the increasing popularity of ecological civilization and sustainable development,enterprises should consider environmental protection measures in their operations in addition to pursue their economic interests.Th...With the increasing popularity of ecological civilization and sustainable development,enterprises should consider environmental protection measures in their operations in addition to pursue their economic interests.This paper establsihes a closed-loop supply chain network model composed of multiple suppliers,manufacturers,retailers,recyclers,and demand markets—regarding their dual goals of the profit maximization and the minimization of carbon emissions.The conditions necessary for establishing overall equilibrium and an equilibrium model of the entire closed-loop supply chain network are determined by applying variational inequality and dual theory.A modified projection contraction algorithm is used to design a model-solving program.Finally,using numerical examples,the paper conducts a comparative static analysis on important parameters such as the weight coefficients of environmental protection objectives and consumers'awareness of low-carbon environmental protection and attains some beneficial enlightenment on management.The results indicate that when the environmental protection objectives of a certain type of enterprise increases,both the economic benefits and environmental protection performance will improve;when the environmental protection objectives of all enterprises increases simultaneously,environmental protection performance improves significantly,but the changes in economic benefits of different enterprises are inconsistent and profit coordination is more complex.Although consumers’awareness of low-carbon preference could improve environmental performance,it reduces the overall profits of network members and the entire closed-loop supply chain network as a whole.The above conclusions can be used as a reference for the government in designing low-carbon environmental protection policy and in closed-loop supply chain research.展开更多
This paper presents the game of production technical standards between downstream and upstream suppliers on a manufacturing supply chain network when the two parties have different partnership densities, namely, the n...This paper presents the game of production technical standards between downstream and upstream suppliers on a manufacturing supply chain network when the two parties have different partnership densities, namely, the numbers of replaceable and mature manufacturing partners. We firstly constructed a manufacturing chain network and analyzed its three relationship structures among suppliers with the presence of different relationship densities, and found that all the three relationships brought about the game of production technical standards between partnership-rich and partnership-scanty suppliers. Then we built a two-party payoff matrix, and analyzed the two-party game and evolutionary stable strategy, based on replication dynamic equation and asymmetric evolutionary game theory. The evolutionary stable strategies of two parties under varying payoff parameters were validated through numerical simulation. Finally, we proposed some suggestions for both those manufacturers with more partners and fewer partners, respectively.展开更多
Decision making in drinking water supply networks is increasingly complex due to the large number of variables involved.In order to make better decisions it is necessary to use adequate and robust methodologies.This p...Decision making in drinking water supply networks is increasingly complex due to the large number of variables involved.In order to make better decisions it is necessary to use adequate and robust methodologies.This paper presents the application of the Analytic Hierarchy Process(AHP)related to the operation of the drinking water supply network of the city of Chihuahua,Mexico,where two possible alternatives are delineated with the objective to optimize the service.The application of AHP was carried out in 24 sectors that have substantial differences in their efficiency but with instrumentation and measurement in all the variables contemplated by the operating agency,with a population of 221,722 inhabitants which represent a 30%of the total population of the city,the results indicate that the best alternative is the one with less criteria to be controlled and fewer repercussions on the cost of operation and investment in the rehabilitation and replacement of the network.展开更多
The potability of drinking water depends not only on the source and the treatment system, but also on the quality of the waterworks. In fact, the quality of drinking water is considerably degraded by the dilapidated s...The potability of drinking water depends not only on the source and the treatment system, but also on the quality of the waterworks. In fact, the quality of drinking water is considerably degraded by the dilapidated state and lack of maintenance of drinking water networks. In Côte d’Ivoire, the majority of drinking water networks in the various towns are ageing. In Daloa, despite the efforts made by the company in charge of water treatment and distribution to make the water drinkable, the water at consumers’ taps is often colored, has an unpleasant aftertaste and settles after collection. As a result, people are concerned about the potability of tap water, and some are turning to alternative sources of drinking water of unknown quality. In order to determine the factors responsible for the deterioration in water color and taste, as well as the sectors of the network most affected, a diagnosis of the network’s equipment was carried out. Water samples taken from the network were analyzed for color and turbidity. The diagnosis revealed that most of the equipment (suction pads, valves, drains and fire hydrants) is outdated and irregularly maintained. Analyses show that the water is more colored in cast-iron and PVC pipes than in asbestos cement pipes. Coloration values in the network range from 0 to 27 UVC for asbestos cement pipes, from 15 to 56 UCV for ductile iron pipes, and from 11 to 102 UCV for PVC pipes. On the over hand, turbidity values vary from 8.02 to 3.32 NTU for ductile cast iron pipes, 8.51 to 16.98 NTU for asbestos cement pipes and 0.9 to 6.98 NTU for PVC pipes. Old cast-iron pipes release ferric ions on contact with water, degrading their color. Old cast-iron pipes release ferric ions into the water, degrading its color. The high color values observed in the vicinity of drains are thought to be due to irregular maintenance of the network. In fact, after network maintenance, a reduction rate ranging from 2% to 73% is observed for turbidity, while for color, the rate varies from 5% to 72%. In short, the network’s obsolescence and irregular maintenance contribute significantly to the deterioration of water quality.展开更多
ZTE Corporation, a leading global provider of telecommunications equipment and network solutions, announced an agreement with Westlink part of the Finish telecommunications group Finnet, to supply a unified multi-serv...ZTE Corporation, a leading global provider of telecommunications equipment and network solutions, announced an agreement with Westlink part of the Finish telecommunications group Finnet, to supply a unified multi-service metro bearer solution on February 18, 2010.展开更多
Supply chain management(SCM)and its associated activities continue to evolve as new communication technologies and cooperative efforts emerge to facilitate system-wide process integration;the context within which supp...Supply chain management(SCM)and its associated activities continue to evolve as new communication technologies and cooperative efforts emerge to facilitate system-wide process integration;the context within which supply chains(SCs)operate,the technologies,and performance enhancement mechanisms have all changed.Thus,linear-based SCs are increasingly being challenged as firms look towards a more networked approach to maximize performance amid growing market dynamics.This paper,however,recognizing inherent similarities between social structure of Social Internet of Things(SIoT)principles and what we term supply community networks(SCN)from literature,seeks to cross-pollinate the two in a way capable of dealing with these market dynamics.Our contribution is,therefore,a new‘setting’of social relationships between supply community agents(SCA)within SCN mirroring interactions played out in the physical world;SCAs autonomously sense each other,exchange information and interact within SCN mimicking the behavior of humans.Also,it identifies the bounds of flow,i.e.all possible dimensions within a SCN which need to be understood to support relationship management.Therefore,communications are improved,sharpening SCAs synchronization in a way responsive to customer needs.展开更多
The industrial supply chain networks basically capture the circulation of social resource, dominating the stability and efficiency of the industrial system. In this paper, we provide an empirical study of the topology...The industrial supply chain networks basically capture the circulation of social resource, dominating the stability and efficiency of the industrial system. In this paper, we provide an empirical study of the topology of smartphone supply chain network. The supply chain network is constructed using open online data. Our experimental results show that the smartphone supply chain network has small-world feature with scale-free degree distribution, in which a few high degree nodes play a key role in the function and can effectively reduce the communication cost. We also detect the community structure to find the basic functional unit. It shows that information communication between nodes is crucial to improve the resource utilization. We should pay attention to the global resource configuration for such electronic production management.展开更多
In this paper we address the problem of pressure management in water supply system （WSS） network. The model-based predictive control （MPC） strategies have some important features to deal with WSS. By hydraulic ana...In this paper we address the problem of pressure management in water supply system （WSS） network. The model-based predictive control （MPC） strategies have some important features to deal with WSS. By hydraulic analysis of WSS, the predictive model is derived from the dynamic model and static model of WSS. Through WSS, the consumers＇ demands are required to be met at all times according to some operational constraints that must be satisfied. The constraints of flow through actuators, the water level of reservoirs and the consumer areas＇ pressure demand are determined by a specific system. In this work, we develop a constrained MPC controller that considers the zone control of the pressure outputs and incorporates steady state economic targets in the control cost function. The designed management strategies are applied to a case study and simulation results, covering different aspects, are provided. The output nodal pressure can be controlled in the desired zone by optimal scheduling the actuators of the WSS. If the variation range of reservoir＇s water level is broader, the rate of flow through the actuators is gentle, and vice versa.展开更多
In order to achieve the goal of social sustainable development and improve the actual utilization rate of water resources, it is necessary to set up the optimal dispatching model of water-saving state of urban water s...In order to achieve the goal of social sustainable development and improve the actual utilization rate of water resources, it is necessary to set up the optimal dispatching model of water-saving state of urban water supply network from the perspective of limited water supply and moderate pressure reduction, so as to fundamentally alleviate the regional water pressure. Based on this, starting from the simulation calculation of water-saving state of urban water supply network, this paper puts forward the optimal scheduling scheme of water-saving state of water supply network for reference.展开更多
In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied...In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares (PLS) regression method provides a model solution which can distinguish between the system information and the noisy data. Finally, a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%, indicating that the model is efficient and feasible, and has better generalization performance.展开更多
After entering the information-based society, profound reform has happened in the business pattern of enterprises, and thecompetitive mode between traditional enterprises has been transformed into the competition betw...After entering the information-based society, profound reform has happened in the business pattern of enterprises, and thecompetitive mode between traditional enterprises has been transformed into the competition between supply chains in nowadays. The liquorindustry in Luzhou is the pillar industry of economy, which involves “Luzhou Old Cellar”, “Ichiro Liquor”and other large-scale enterpriseswith well-known brands. Besides, many small and medium-sized enterprises are developing and flourishing in Luzhou. Compared with thedevelopment of large enterprises, the development of small and medium sized enterprises has more uncertainty and risks. At present, Luzhou Cityis setting about to build Huangyi into a liquor centralized zone, which is also a clusterization strategy for industry development of Luzhou liquor.For Luzhou Liquor Zone, the implementation of supply chain management of small and medium-sized enterprises can greatly reduce the cost ofenterprises and improve effi ciency of operation. The growth and development of small and medium-sized enterprises in Luzhou Liquor Zone andthe promotion of advantages of industrial clusters are closely related to the risks of the supply chain.展开更多
In recent years,global supply chains face great challenges driven by events such as trade wars,the Covid-19 pandemic,and the Russia-Ukraine War.Since the disruptions caused by such shocks are more systematic and the d...In recent years,global supply chains face great challenges driven by events such as trade wars,the Covid-19 pandemic,and the Russia-Ukraine War.Since the disruptions caused by such shocks are more systematic and the duration is harder to predict compared to natural disasters or other operational risks,we highlight two features for future supply chain research:network perspectives and incorporation of more stakeholders such as governments that can influence overarching performances of industrial and supply chains.From the network perspective,we review the literature on vulnerable nodes&links identification,risk propagation modeling,network resilience measures,and disruption mitigation strategies.We suggest promising research directions such as deriving non-probabilistic resilience measures that can incorporate dynamics,extending existing methods for bottleneck detection to the network setting,balancing efficiency and resilience in a more sophisticated way,etc.In terms of incorporating more stakeholders’roles in supply chain network decisions,we review the relevant literature and discuss research opportunities on governments’roles in global supply chains(i.e.,an external circulation perspective)and in incentivizing firms’R&D and stimulating domestic demand(i.e.,an internal circulation perspective).We suggest topics including global supply chain resilience evaluation using trade networks,technology networks,and firm ownership networks,the impact of trade policies with network perspectives,design of tariffand non-tariffmeasures under trade agreements,domestic industry relocation,evaluating the effects of government subsidies on firms’long-term innovation,and design of subsidy strategies for supply chain stability and resilience.We believe research on supply chain resilience will thrive in the years ahead,better supporting firms’and governments’decisions.展开更多
基金Humanities and Social Sciences Project of the Ministry of Education of China,No.23YJCZH195Scientific Research Program funded by the Shaanxi Provincial Education Department,No.20JK0358, No.21JK0908+2 种基金Natural Science Basic Research Program of Shaanxi,No.2024JC-YBQN-0738, No.2023-JC-QN-0560Shaanxi Provincial Education Science Planning Project,No.SGH23Y2484China Logistics Society&China Federation of Logistics and Purchasing Research Fund,No.2023CSLKT3-220。
文摘An appropriate spatial structure of a power battery supply network is crucial for the specialization and scale development of key components in new energy vehicles, accelerating the transformation and upgrade of the industry. This paper investigates the cooperative relationships among supply chain enterprises from the perspective of complex networks.Employing methodologies such as the gravity model and Moran's I analysis, it explores the spatial structural characteristics and correlation patterns of the power battery supply network in China and discusses the influencing factors using the quadratic assignment procedure,revealing the mechanisms behind the differences in the spatial distributions of the power battery supply network. The results indicate that the distribution of power battery enterprises is densely concentrated in the eastern and southern regions, whereas the western region has a sparse distribution. The spatial supply network consists of a four-tier linkage system, encompassing 135 prefecture-level cities, with Chongqing, Shanghai, Nanjing, and other cities particularly prominent. Overall, the degree of agglomeration is low, with coastal cities dominating the landscape and inland cities serving as complementary regions. Most areas are characterized as insignificant or low-high regions, and the regional linkage effect of core cities is not pronounced. There is a notable lack of significance and high spatial heterogeneity.Four types of factors—spatial factors, market factors, agglomeration economies, and innovation levels—jointly influence and shape the spatial structure of the power battery supply network.
文摘Using a modified subgradient extragradient algorithm, this paper proposed a novel approach to solving a supply chain network equilibrium model. The method extends the scope of optimisation and improves the accuracy at each iteration by incorporating adaptive parameter selection and a more general subgradient projection operator. The advantages of the proposed method are highlighted by the proof of strong convergence presented in the paper. Several concrete examples are given to demonstrate the effectiveness of the algorithm, with comparisons illustrating its superior CPU running time compared to alternative techniques. The practical applicability of the algorithm is also demonstrated by applying it to a realistic supply chain network model.
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘The classical supply chain network(SCN)design problem is extended,where the candidate facilities are subject to failure and the products are prone to elapsed time deteriorion.First,the reliable SCN design problem is defined by introducing the probability that a facility may be prone to inactivity based on the analysis of perishable product characteristics.The perishable product SCN design problem is formulated as a 0-1 integer programming model.The objective is to minimize the weighted sum of the operating cost(the fixed plus transportation cost)and the expected failure cost.And then,the perishable product SCN design model is discussed and solved using the genetic algorithm(GA).The results show how to generate the tradeoff curve between the operating costs and the expected failure costs.And these tradeoff curves demonstrate empirically that substantial improvements in reliability are often possible with minimal increase in the operating costs.
基金the Institute of Engineering Mechanics(IEM),China Earthquake Administration(CEA)under Grant No.2019EEEVL0505the National Natural Science Foundation of China under Grant No.51908519and the Scientific Research Fund of the IEM,CEA under Grant No.2019B02。
文摘An urban water supply network(WSN)is a crucial lifeline system that helps to maintain the normal functioning of modern society.However,the hydraulic analysis of a significantly damaged WSN that suffers from pipe breaks or leaks remains challenging.In this paper,a probability-based framework is proposed to assess the functionality of WSNs in the aftermath of powerful earthquakes.The serviceability of the WSN is quantified by using a comprehensive index that considers nodal water flow and nodal pressure.This index includes a coefficient that reflects the relative importance of these two parameters.The demand reduction(DR)method,which reduces the water flow of nodes while preventing the negative pressure of nodes,is proposed.The difference between the negative pressure elimination(NPE)method and the DR method is discussed by using the example of a WSN in a medium-sized city in China.The functionality values of the WSN are 0.76 and 0.99 when nodal pressure and nodal demands are used respectively as the index of system serviceability at an intensity level that would pertain to an earthquake considered to occur at a maximum level.When the intensity of ground motion is as high as 0.4 g,the DR method requires fewer samples than the NPE method to obtain accurate results.The NPE method eliminates most of the pipes,which may be unrealistic.
基金National Natural Science Foundation of China under Grant No.5210082055China Postdoctoral Science Foundation under Grant No.2021M690278。
文摘The serviceability of water supply networks(WSNs)under seismic loads has significant importance for estimating the probable losses and the impact of diminished functionality on affected communities.The innovation presented in this paper is suggesting a new strategy to evaluate the seismic serviceability of WSNs,utilizing their operational physical mechanism.On one hand,this method can obtain the seismic serviceability of each node as well as entire WSNs.On the other hand,this method can dynamically reflect the propagation of randomness from ground motions to WSNs.First,a finite element model is established to capture the seismic response of buried pipe networks,and a leakage model is suggested to obtain the leakage area of WSNs.Second,the transient flow analysis of WSNs with or without leakage is derived to obtain dynamic water flow and pressure.Third,the seismic serviceability of WSNs is analyzed based on the probability density evolution method(PDEM).Finally,the seismic serviceability of a real WSN in Mianzhu city is assessed to illustrate the method.The case study shows that randomness from the ground motions can obviously affect the leakage state and the probability density of the nodal head during earthquakes.
基金the Natural Science Key Foundation of Heilongjiang Province of China (No. ZJG0503) China-UK Sci-ence Network from Royal Society UK
文摘Through the transformation of hydraulic constraints into the objective functions associated with a water supply network rehabilitation problem, a non-dominated sorting Genetic Algorithm-II (NSGA-II) can be used to solve the altered multi-objective optimization model. The introduction of NSGA-II into water supply network optimal rehabilitation problem solves the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. And the uncertainties brought by using weight coefficients or punish functions in conventional methods are controlled. And also by in-troduction of artificial inducement mutation (AIM) operation, the convergence speed of population is accelerated;this operation not only improves the convergence speed, but also improves the rationality and feasibility of solutions.
基金supported by the National Key Technology R&D Program of China (No. 2006BAH02A06)"333 Engineering"Project of Jiangsu Province
文摘Contract is a common and effective mechanism for supply chain coordination,which has been studied extensively in recent years.For a supply chain network model,contracts can be used to coordinate it because it is too ideal to obtain the network equilibrium state in practical market competition.In order to achieve equilibrium,we introduce revenue sharing contract into a supply chain network equilibrium model with random demand in this paper.Then,we investigate the influence on this network equilibrium state from demand disruptions caused by unexpected emergencies.When demand disruptions happen,the supply chain network equilibrium state will be broken and change to a new one,so the decision makers need to adjust the contract parameters to achieve the new coordinated state through bargaining.Finally,a numerical example with a sudden demand increase as a result of emergent event is provided for illustrative purposes.
基金The National Natural Science Foundation of China(No.70571033)the National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘The supply chain network with capacity constraints of manufacturers and retailers is considered.The linkage between supply chain network equilibrium and transportation network equilibrium is investigated.By analyzing the relationships among the manufacturers,retailers and consumers in the supply chain network and their own decisions concerning maximum profits,a combined variational inequality for the supply chain network equilibrium mode is proposed.Then an equivalent supernetwork of the supply chain network is constructed by adding additional links which denote the producing of manufactures and the handling of retailers.By the supernetwork,the supply chain network equilibrium model can be reformulated as a transportation network equilibrium model.Equivalent mathematical programming is,therefore,obtained based on the principle of a Wardrop user equilibrium.The corresponding Lagrange multiplier of the capacity constraints can be explained as the extra cost of marginal production when capacity is exceeded.A numerical example is given to illustrate the rationality of the model and the validity of the results.
基金supported by Humanity and Social Science Foundation of Ministry of Education of China[Grant number 17YJA630130].
文摘With the increasing popularity of ecological civilization and sustainable development,enterprises should consider environmental protection measures in their operations in addition to pursue their economic interests.This paper establsihes a closed-loop supply chain network model composed of multiple suppliers,manufacturers,retailers,recyclers,and demand markets—regarding their dual goals of the profit maximization and the minimization of carbon emissions.The conditions necessary for establishing overall equilibrium and an equilibrium model of the entire closed-loop supply chain network are determined by applying variational inequality and dual theory.A modified projection contraction algorithm is used to design a model-solving program.Finally,using numerical examples,the paper conducts a comparative static analysis on important parameters such as the weight coefficients of environmental protection objectives and consumers'awareness of low-carbon environmental protection and attains some beneficial enlightenment on management.The results indicate that when the environmental protection objectives of a certain type of enterprise increases,both the economic benefits and environmental protection performance will improve;when the environmental protection objectives of all enterprises increases simultaneously,environmental protection performance improves significantly,but the changes in economic benefits of different enterprises are inconsistent and profit coordination is more complex.Although consumers’awareness of low-carbon preference could improve environmental performance,it reduces the overall profits of network members and the entire closed-loop supply chain network as a whole.The above conclusions can be used as a reference for the government in designing low-carbon environmental protection policy and in closed-loop supply chain research.
基金Supported by the Science and Technology Development Strategy Research Project of Tianjin(13ZLZLZF08900)
文摘This paper presents the game of production technical standards between downstream and upstream suppliers on a manufacturing supply chain network when the two parties have different partnership densities, namely, the numbers of replaceable and mature manufacturing partners. We firstly constructed a manufacturing chain network and analyzed its three relationship structures among suppliers with the presence of different relationship densities, and found that all the three relationships brought about the game of production technical standards between partnership-rich and partnership-scanty suppliers. Then we built a two-party payoff matrix, and analyzed the two-party game and evolutionary stable strategy, based on replication dynamic equation and asymmetric evolutionary game theory. The evolutionary stable strategies of two parties under varying payoff parameters were validated through numerical simulation. Finally, we proposed some suggestions for both those manufacturers with more partners and fewer partners, respectively.
文摘Decision making in drinking water supply networks is increasingly complex due to the large number of variables involved.In order to make better decisions it is necessary to use adequate and robust methodologies.This paper presents the application of the Analytic Hierarchy Process(AHP)related to the operation of the drinking water supply network of the city of Chihuahua,Mexico,where two possible alternatives are delineated with the objective to optimize the service.The application of AHP was carried out in 24 sectors that have substantial differences in their efficiency but with instrumentation and measurement in all the variables contemplated by the operating agency,with a population of 221,722 inhabitants which represent a 30%of the total population of the city,the results indicate that the best alternative is the one with less criteria to be controlled and fewer repercussions on the cost of operation and investment in the rehabilitation and replacement of the network.
文摘The potability of drinking water depends not only on the source and the treatment system, but also on the quality of the waterworks. In fact, the quality of drinking water is considerably degraded by the dilapidated state and lack of maintenance of drinking water networks. In Côte d’Ivoire, the majority of drinking water networks in the various towns are ageing. In Daloa, despite the efforts made by the company in charge of water treatment and distribution to make the water drinkable, the water at consumers’ taps is often colored, has an unpleasant aftertaste and settles after collection. As a result, people are concerned about the potability of tap water, and some are turning to alternative sources of drinking water of unknown quality. In order to determine the factors responsible for the deterioration in water color and taste, as well as the sectors of the network most affected, a diagnosis of the network’s equipment was carried out. Water samples taken from the network were analyzed for color and turbidity. The diagnosis revealed that most of the equipment (suction pads, valves, drains and fire hydrants) is outdated and irregularly maintained. Analyses show that the water is more colored in cast-iron and PVC pipes than in asbestos cement pipes. Coloration values in the network range from 0 to 27 UVC for asbestos cement pipes, from 15 to 56 UCV for ductile iron pipes, and from 11 to 102 UCV for PVC pipes. On the over hand, turbidity values vary from 8.02 to 3.32 NTU for ductile cast iron pipes, 8.51 to 16.98 NTU for asbestos cement pipes and 0.9 to 6.98 NTU for PVC pipes. Old cast-iron pipes release ferric ions on contact with water, degrading their color. Old cast-iron pipes release ferric ions into the water, degrading its color. The high color values observed in the vicinity of drains are thought to be due to irregular maintenance of the network. In fact, after network maintenance, a reduction rate ranging from 2% to 73% is observed for turbidity, while for color, the rate varies from 5% to 72%. In short, the network’s obsolescence and irregular maintenance contribute significantly to the deterioration of water quality.
文摘ZTE Corporation, a leading global provider of telecommunications equipment and network solutions, announced an agreement with Westlink part of the Finish telecommunications group Finnet, to supply a unified multi-service metro bearer solution on February 18, 2010.
文摘Supply chain management(SCM)and its associated activities continue to evolve as new communication technologies and cooperative efforts emerge to facilitate system-wide process integration;the context within which supply chains(SCs)operate,the technologies,and performance enhancement mechanisms have all changed.Thus,linear-based SCs are increasingly being challenged as firms look towards a more networked approach to maximize performance amid growing market dynamics.This paper,however,recognizing inherent similarities between social structure of Social Internet of Things(SIoT)principles and what we term supply community networks(SCN)from literature,seeks to cross-pollinate the two in a way capable of dealing with these market dynamics.Our contribution is,therefore,a new‘setting’of social relationships between supply community agents(SCA)within SCN mirroring interactions played out in the physical world;SCAs autonomously sense each other,exchange information and interact within SCN mimicking the behavior of humans.Also,it identifies the bounds of flow,i.e.all possible dimensions within a SCN which need to be understood to support relationship management.Therefore,communications are improved,sharpening SCAs synchronization in a way responsive to customer needs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11547040 and 61703281)Guangdong Province Natural Science Foundation,China(Grant Nos.2016A030310051 and 2015KONCX143)+4 种基金Shenzhen Fundamental Research Foundation,China(Grant Nos.JCYJ20150625101524056 and JCYJ20160520162743717)SZU Student Innovation Fund,China,the PhD Start-up Fund of Natural Science Foundation of Guangdong Province,China(Grant No.2017A030310374)the Young Teachers Start-up Fund of Natural Science Foundation of Shenzhen University,Chinathe Natural Science Foundation of SZU,China(Grant No.2016-24)the Singapore Ministry of Education Academic Research Fund Tier 2(Grant No.MOE 2013-T2-2-033)
文摘The industrial supply chain networks basically capture the circulation of social resource, dominating the stability and efficiency of the industrial system. In this paper, we provide an empirical study of the topology of smartphone supply chain network. The supply chain network is constructed using open online data. Our experimental results show that the smartphone supply chain network has small-world feature with scale-free degree distribution, in which a few high degree nodes play a key role in the function and can effectively reduce the communication cost. We also detect the community structure to find the basic functional unit. It shows that information communication between nodes is crucial to improve the resource utilization. We should pay attention to the global resource configuration for such electronic production management.
基金supported by National Natural Science Foundation of China(Nos.61233004 and 61221003)the National Basic Research Program of China(973 Program)(No.2013CB035500)the Higher Education Research Fund for the Doctoral Program of China(No.20120073130006)
文摘In this paper we address the problem of pressure management in water supply system （WSS） network. The model-based predictive control （MPC） strategies have some important features to deal with WSS. By hydraulic analysis of WSS, the predictive model is derived from the dynamic model and static model of WSS. Through WSS, the consumers＇ demands are required to be met at all times according to some operational constraints that must be satisfied. The constraints of flow through actuators, the water level of reservoirs and the consumer areas＇ pressure demand are determined by a specific system. In this work, we develop a constrained MPC controller that considers the zone control of the pressure outputs and incorporates steady state economic targets in the control cost function. The designed management strategies are applied to a case study and simulation results, covering different aspects, are provided. The output nodal pressure can be controlled in the desired zone by optimal scheduling the actuators of the WSS. If the variation range of reservoir＇s water level is broader, the rate of flow through the actuators is gentle, and vice versa.
文摘In order to achieve the goal of social sustainable development and improve the actual utilization rate of water resources, it is necessary to set up the optimal dispatching model of water-saving state of urban water supply network from the perspective of limited water supply and moderate pressure reduction, so as to fundamentally alleviate the regional water pressure. Based on this, starting from the simulation calculation of water-saving state of urban water supply network, this paper puts forward the optimal scheduling scheme of water-saving state of water supply network for reference.
基金Supported by Tianjin Natural Science Foundation( No. 003611611).
文摘In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares (PLS) regression method provides a model solution which can distinguish between the system information and the noisy data. Finally, a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%, indicating that the model is efficient and feasible, and has better generalization performance.
文摘After entering the information-based society, profound reform has happened in the business pattern of enterprises, and thecompetitive mode between traditional enterprises has been transformed into the competition between supply chains in nowadays. The liquorindustry in Luzhou is the pillar industry of economy, which involves “Luzhou Old Cellar”, “Ichiro Liquor”and other large-scale enterpriseswith well-known brands. Besides, many small and medium-sized enterprises are developing and flourishing in Luzhou. Compared with thedevelopment of large enterprises, the development of small and medium sized enterprises has more uncertainty and risks. At present, Luzhou Cityis setting about to build Huangyi into a liquor centralized zone, which is also a clusterization strategy for industry development of Luzhou liquor.For Luzhou Liquor Zone, the implementation of supply chain management of small and medium-sized enterprises can greatly reduce the cost ofenterprises and improve effi ciency of operation. The growth and development of small and medium-sized enterprises in Luzhou Liquor Zone andthe promotion of advantages of industrial clusters are closely related to the risks of the supply chain.
基金supported in part by the National Natural Science Foundation of China(72091211,72293560/72293565 and 72025102).
文摘In recent years,global supply chains face great challenges driven by events such as trade wars,the Covid-19 pandemic,and the Russia-Ukraine War.Since the disruptions caused by such shocks are more systematic and the duration is harder to predict compared to natural disasters or other operational risks,we highlight two features for future supply chain research:network perspectives and incorporation of more stakeholders such as governments that can influence overarching performances of industrial and supply chains.From the network perspective,we review the literature on vulnerable nodes&links identification,risk propagation modeling,network resilience measures,and disruption mitigation strategies.We suggest promising research directions such as deriving non-probabilistic resilience measures that can incorporate dynamics,extending existing methods for bottleneck detection to the network setting,balancing efficiency and resilience in a more sophisticated way,etc.In terms of incorporating more stakeholders’roles in supply chain network decisions,we review the relevant literature and discuss research opportunities on governments’roles in global supply chains(i.e.,an external circulation perspective)and in incentivizing firms’R&D and stimulating domestic demand(i.e.,an internal circulation perspective).We suggest topics including global supply chain resilience evaluation using trade networks,technology networks,and firm ownership networks,the impact of trade policies with network perspectives,design of tariffand non-tariffmeasures under trade agreements,domestic industry relocation,evaluating the effects of government subsidies on firms’long-term innovation,and design of subsidy strategies for supply chain stability and resilience.We believe research on supply chain resilience will thrive in the years ahead,better supporting firms’and governments’decisions.
