The adoption of new technologies often represents a crucial component of firms' investment decisions. This paper studies a dynamic duopoly model in which two firms compete in adoption of current technology with a fur...The adoption of new technologies often represents a crucial component of firms' investment decisions. This paper studies a dynamic duopoly model in which two firms compete in adoption of current technology with a further new technology anticipated. Here it is assumed that the operating costs are not zero which has more explanatory power of the real world. There exist three kinds of equilibria that may occur in adoption of current technology, which mainly depends on the level of operating costs and the first-move advantage. It shows that the faster technological substitution or innovation encourages the leader to invest earlier while induces the follower to invest later. Furthermore,like the investment costs,with the increase of operating costs the follower tends to invest later while the leader tends to invest earlier ,the investment thresholds are more sensitive to the change of operating costs than that of investment costs.展开更多
The purpose of this paper is to approach the administrative costs in the field of education and to answer questions such as:How are administrative costs measured and evaluated?Is it taken into account in the analysis ...The purpose of this paper is to approach the administrative costs in the field of education and to answer questions such as:How are administrative costs measured and evaluated?Is it taken into account in the analysis of policy options?Administrative costs affect all areas of public education and absorb a large part of the state budget appropriations intended for education.Through the presentation of the general and specific objectives but also the European participation in the rational management of the management costs of the educational units,we lead to a holistic approach to the operational costs of the education that is part of the social costs.展开更多
The application of floating photovoltaics (PVs) in hydropower plants has gained increasing interest in forming hybrid energy systems (HESs). It enhances the operational benefits of the existing hydropower plants. Howe...The application of floating photovoltaics (PVs) in hydropower plants has gained increasing interest in forming hybrid energy systems (HESs). It enhances the operational benefits of the existing hydropower plants. However, uncertainties of PV and load powers can present great challenges to scheduling HESs. To address these uncertainties, this paper proposes a novel two-stage optimization approach that combines distributionally robust chance-constrained (DRCC) and robust-stochastic optimization (RSO) approaches to minimize the operational cost of an HES. In the first stage, the scheduling of each device is obtained via the DRCC approach considering the PV power and load forecast errors. The second stage provides a robust near real time energy dispatch according to different scenarios of PV power and load demand. The solution of the RSO problem is obtained via a novel double-layer particle swarm optimization algorithm. The performance of the proposed approach is compared to the traditional stochastic and robust-stochastic approaches. Simulation results de- monstrate the superiority of the proposed two-stage approach and its solution method in terms of operational cost and execution time.展开更多
目的对经外周置入中心静脉导管(peripherally inserted central catheter,PICC)置管、维护及拔管的单项操作成本进行核算,为制定合理的操作收费价格提供依据。方法通过横断面调查,采用项目成本阶梯分摊法,于2019年1—5月在复旦大学附属...目的对经外周置入中心静脉导管(peripherally inserted central catheter,PICC)置管、维护及拔管的单项操作成本进行核算,为制定合理的操作收费价格提供依据。方法通过横断面调查,采用项目成本阶梯分摊法,于2019年1—5月在复旦大学附属肿瘤医院血管通路门诊测算PICC各单项操作人力成本、设备折旧费及未单独计价材料费,测算直接成本,并通过分摊测算间接成本,最后测算PICC置管、维护及拔管的单项操作成本。结果PICC置管、维护及拔管的各单项操作实际成本分别为(157.03±4.73)元、(33.66±3.04)元、(32.38±3.11)元,与上海市医疗机构对PICC各项操作的收费标准(分别为150元、30元、30元)基本相符。结论建议将PICC维护及拔管的操作收费纳入收费标准中,促进PICC输液技术的可持续发展并确保护理服务的持续供给。展开更多
We apply the simplex algorithm which is a branch of linear programming to efficiently determine the allocation of resources required to operate a company in the software development field. The main aim of applying thi...We apply the simplex algorithm which is a branch of linear programming to efficiently determine the allocation of resources required to operate a company in the software development field. The main aim of applying this technique is to maximize the profit of a company under certain limitations. This <span>can be done using the trial-and-error approach. However, this tedious</span> process can be replaced by user-level tools such as Excel which are based on linear programming that will give more accurate results. Small software companies cannot afford to hire a high number of senior programmers to produce the required level of quality and to keep up with the demand for adding new features. On the other hand, lowering the quality of the product will reduce the number of customers and decrease profit. Another aspect is maximizing the utilization of hosting servers which are required for providing the services to customers since the cost of buying servers and maintaining them is extremely high. The simplex algorithm in linear programming will take the specified <span>constraints into account to compute the optimal allocation of the available</span> <span>resources to maximize profit and limit the cost. This paper will present a</span> <span>model that uses the simplex algorithm with a set of constraints to determine</span> how many projects of each type a company should take in one period of time.展开更多
A continuous-flow ultrasound-assisted oxidative desulfurization(UAOD)of partially hydro-treated diesel has been investigated using hydrogen peroxide-formic acid as simple and easy to apply oxidation system.The effects...A continuous-flow ultrasound-assisted oxidative desulfurization(UAOD)of partially hydro-treated diesel has been investigated using hydrogen peroxide-formic acid as simple and easy to apply oxidation system.The effects of different operating parameters of oxidation stage including residence time(2–24 min),formic acid to sulfur molar ratio(10–150),and oxidant to sulfur molar ratio(5–35)on the sulfur removal have been studied using response surface methodology(RSM)based on Box–Behnken design.Considering the operating costs of the continuous-flow oxidation stage including chemical and electrical energy consumption,the appropriate values of operating parameters were selected as follows:residence time of 16 min,the formic acid to sulfur molar ratio of 54.47,and the oxidant to sulfur molar ratio of 8.24.In these conditions,the sulfur removal and the volume ratio of the hydrocarbon phase to the aqueous phase were 86.90%and 4.34,respectively.By drastic reduction in the chemical consumption in the oxidation stage,the volume ratio of the hydrocarbon phase to the aqueous phase was increased up to 10.Therefore,the formic acid to sulfur molar ratio and the oxidant to sulfur molar ratio were obtained 23.64 and 3.58,respectively,which lead to sulfur removal of 84.38%with considerable improvements on the operating cost of oxidation stage in comparison with the previous works.展开更多
Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mix...Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mixture is explored. An evaluating method is proposed, and the pertinent optimization model is then derived. The ethanol-water system is studied as an illustrative example. The optimization results show that the maximum energy saving in ITCDIC process is about 35% and the maximum operating cost saving in ITCDIC process is about 30%,as compared with a conventional distillation column(CDIC) under the minimum reflux ratio operating; the optimal operating pressure of the rectifying section is found to be around 0.25 MPa; the effects of the feed composition,operating pressure and the heat transfer rate on operation are also found and analyzed. It is revealed that ITCDIC process possesses high energy saving potential and promising economical prospect.展开更多
The beer game model is a typical paradigm used to study complex dynamics behaviours in production–distribution systems. The model, however, does not accord with current practical supply chain system models in discret...The beer game model is a typical paradigm used to study complex dynamics behaviours in production–distribution systems. The model, however, does not accord with current practical supply chain system models in discrete?type manufacturing industry, which are generally composed of retailers, distributors, manufacturers with internal sup?ply chain, and suppliers. To describe how ordering policies influence the complex dynamics behaviour modes and operating cost in a general discrete?type manufacturing industry supply chain system, a high dimension piecewise?linear dynamics model is built for the supply chain system. Five kinds of ordering policy combination are considered. The distribution of both the largest Lyapunov exponent of e ective inventory and average operating cost per cycle is obtained by simulation in a policy space. The simulation shows that for the general discrete?type manufacturing industry supply chain system, the upper chaotic corners emerge besides the lower chaotic corners in the policy space expressing the distribution of system behaviour mode, and that the ordering policies at each supply chain node as well as their combination have very significant e ect on the topology of the distribution of both system behaviour mode and operating cost in the policy space. We find that chaos is not always corresponding to high cost, and the "chaos amplification" is not completely relevant to the "cost amplification".展开更多
Based on the analysis of inherent limitations in existing security response decision-making systems, a dynamic adaptive model of fault response is presented. Several security fault levels were founded, which comprise ...Based on the analysis of inherent limitations in existing security response decision-making systems, a dynamic adaptive model of fault response is presented. Several security fault levels were founded, which comprise the basic level, equipment level and mechanism level. Fault damage cost is calculated using the analytic hierarchy process. Meanwhile, the model evaluates the impact of different responses upon fault repair and normal operation. Response operation cost and response negative cost are introduced through quantitative calculation. This model adopts a comprehensive response decision of security fault in three principles--the maximum and minimum principle, timeliness principle, acquiescence principle, which assure optimal response counter- measure is selected for different situations. Experimental results show that the proposed model has good self- adaptation ability, timeliness and cost-sensitiveness.展开更多
The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will ...The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will greatly deepen the coupling of the electricity-gas integrated energy system,improve the flexibility and safety of the operation of the power system,and bring a deal of benefits to the power system.On this background,an optimal dispatch model of RIES combined cold,heat,gas and electricity with SOP is proposed.Firstly,RIES architecture with SOP and P2G is designed and its mathematical model also is built.Secondly,on the basis of considering the optimal scheduling of combined cold,heat,gas and electricity,the optimal scheduling model for RIES was established.After that,the original model is transformed into a mixed-integer second-order cone programming model by using linearization and second-order cone relaxation techniques,and the CPLEX solver is invoked to solve the optimization problem.Finally,the modified IEEE 33-bus systemis used to analyze the benefits of SOP,P2G technology and lithium bromide absorption chillers in reducing systemnetwork loss and cost,as well as improving the system’s ability to absorb wind and solar and operating safety.展开更多
Since July 2014,when the international oil price slumped,the upstream sector of global oil and gas industry has experienced a tough transformation phase lasting over two years.In terms of the development trend,the glo...Since July 2014,when the international oil price slumped,the upstream sector of global oil and gas industry has experienced a tough transformation phase lasting over two years.In terms of the development trend,the global upstream sector has demonstrated six characteristics since 2017:firstly,global upstream investment will probably demonstrate the trend of "touching the ground and rising again";secondly,upstream operating costs will continually decline;thirdly,more favorable finance and taxation clauses will be offered for some resources to be developed through foreign cooperation;fourthly,global oil and gas output will probably further increase;fifthly,upstream exploration efficiency is anticipated to steadily increase;and sixthly,upstream geological understandings,theory and technology will continue to advance.In accordance with the above-mentioned development trends,Chinese oil enterprises must be prepared in four aspects for future rejuvenation.Firstly,persistent upstream investment has to be guaranteed,particularly in the exploration field;secondly,upstream operation efficiency must be promoted through the enhancement of technical research;thirdly,overseas upstream property must be purchased within the "time window";and fourthly,reforms have to be carried out to realize transformation in the petroleum industry.展开更多
Treatment of Indigo dye (leuco form), reduced in the industrial conditions of the SITEX (Textile Industrial Company), by a batch electrocoagulation using aluminum electrodes. Response Surface Methodology (RSM) and Box...Treatment of Indigo dye (leuco form), reduced in the industrial conditions of the SITEX (Textile Industrial Company), by a batch electrocoagulation using aluminum electrodes. Response Surface Methodology (RSM) and Box-Behnken design were used to optimize for Color Removal (CR(%)). Our results showed that the quadratic second order equation provided the best correlation for the decolorization of Indigo dye (CR(%)). On the other hand, the ANOVA analysis proved the large interaction between the current intensity and the initial concentration of the dye. Experiments were conducted to find the desired conditions for removal of particular concentration of the dye and lower Operation Cost. The results showed that CR(%) = 88.3% (R<sup>2</sup>) of color removal for initial dye concentration of 12.31 mg/l, with a current density of 2.81 A/m<sup>2</sup>, solution concentration of NaCl of 2.67 g/l. Under these conditions, Electrical Energy Consumption (EEC) and Electrode Consumption (EMC) and Operation Cost were 0.01999 kWh/m<sup>3</sup> (R<sup>2</sup> = 93.1%), 0.00142768 Kg/m<sup>3</sup> (R<sup>2</sup> = 79.4%) and 0.000558 US$/m<sup>3</sup>, respectively.展开更多
The operational stability and economy of multi-energy systems(MES)are threatened by various uncertainties,such as variable renewable energy power,energy demands,and weather conditions.Most of the existing methods for ...The operational stability and economy of multi-energy systems(MES)are threatened by various uncertainties,such as variable renewable energy power,energy demands,and weather conditions.Most of the existing methods for the dispatch decisions of MES are based on the prescribed probability distribution or uncertainty sets of random variables,which have many disadvantages,such as potential infeasibility and over-conservatism.In this paper,we propose a novel dispatch model for MES that integrates dispatch decision making,uncertainty set selection,and operational cost control into a unified framework.First,the deterministic dispatch model of MES is introduced,in which the physical characteristics of district heating systems and buildings are fully considered.Then,a novel decision framework that combines the two-stage dispatch strategy and info-gap decision theory(IGDT)is proposed for MES,where the uncertainty set is flexible and can be optimized based on the operational cost budget.Finally,a revised algorithm,based on the column-and-constraint generation method,is proposed for the model.Case studies are performed on MES that includes a 33-bus distribution system and a heating network modified from a real 51-node network located in Jinlin Province,China.The results verify the effectiveness of the proposed method.展开更多
In the electricity market environment,the regional integrated energy system(RIES)can reduce the total operation cost by participating in electricity market transactions.However,the RIES will face the risk of load and ...In the electricity market environment,the regional integrated energy system(RIES)can reduce the total operation cost by participating in electricity market transactions.However,the RIES will face the risk of load and electricity price uncertainties,which may make its operation cost higher than expected.This paper proposes a method to optimize the operation cost of the RIES in the electricity market environment considering uncertainty.Firstly,based on the operation cost structure of the RIES in the electricity market environment,the energy flow relationship of the RIES is analyzed,and the operation cost model of the RIES is built.Then,the electricity purchase costs of the RIES in the medium-and long-term electricity markets,the spot electricity market,and the retail electricity market are analyzed.Finally,considering the risk of load and electricity price uncertainties,the operation cost optimization model of the RIES is established based on conditional value-at-risk.Then it is solved to obtain the operation cost optimization strategy of the RIES.Verification results show that the proposed operation cost optimization method can reduce the operation cost of high electricity price scenario by optimizing the energy purchase and distribution strategy,constrain the risk of load and electricity price uncertainties,and help balance the risks and benefits.展开更多
Based on the value function of the prospect theory,this paper constructs a security function,which is used to describe the victims’feelings about the distance in emergency evacuation.Since different paths between the...Based on the value function of the prospect theory,this paper constructs a security function,which is used to describe the victims’feelings about the distance in emergency evacuation.Since different paths between the demand points and the emergency shelters are generally of different importance degrees,they are divided into main paths and auxiliary paths.The security function values and the reliability levels of main paths and auxiliary paths are given different weights.The weighted sum of the security function values and the weighted sum of the reliability level function values of all demand points are maximized to determine the location and the number of the emergency shelters,the transfer paths,the reinforced edges and the incremental reliability level of the selected edge.In order to solve the model,a two-stage simulated annealing-particle swarm optimization algorithm is proposed.In this algorithm,the particle swarm optimization(PSO)algorithm is embedded into the simulated annealing(SA)algorithm.The cumulative probability operator and the cost probability operator are formed to determine the evolution of the particles.Considering the budget constraint,the algorithm eliminates the shelter combinations that do not meet the constraint,which greatly saves the calculation time and improves the efficiency.The proposed algorithm is applied to a case,which verifies its feasibility and stability.The model and the algorithm of this paper provide a basis for emergency management departments to make the earthquake emergency planning.展开更多
Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requiremen...Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requirement for aircraft design. In this paper, estimation method for emis- sion in aircraft conceptual design stage is improved based on the International Civil Aviation Orga- nization (ICAO) aircraft engine emissions databank and the polynomial curve fitting methods. The greenhouse gas emission (CO2 equivalent) per seat per kilometer is proposed to measure the emis- sions. An approximate sensitive analysis and a multi-objective optimization of aircraft design for tradeoff between greenhouse effect and direct operating cost (DOC) are performed with five geom- etry variables of wing configuration and two flight operational parameters. The results indicate that reducing the cruise altitude and Mach number may result in a decrease of the greenhouse effect but an increase of DOC. And the two flight operational parameters have more effects on the emissions than the wing configuration. The Pareto-optimal front shows that a decrease of 29.8% in DOC is attained at the expense of an increase of 10.8% in greenhouse gases.展开更多
Current multi-operator image resizing methods succeed in generating impressive results by using image similarity measure to guide the resizing process. An optimal operation path is found in the resizing space. However...Current multi-operator image resizing methods succeed in generating impressive results by using image similarity measure to guide the resizing process. An optimal operation path is found in the resizing space. However, their slow resizing speed caused by inefficient computation strategy of the bidirectional patch matching becomes a drawback in practical use. In this paper, we present a novel method to address this problem. By combining seam carving with scaling and cropping, our method can realize content-aware image resizing very fast. We define cost functions combing image energy and dominant color descriptor for all the operators to evaluate the damage to both local image content and global visual effect. Therefore our algorithm can automatically find an optimal sequence of operations to resize the image by using dynamic programming or greedy algorithm. We also extend our algorithm to indirect image resizing which can protect the aspect ratio of the dominant object in an image.展开更多
In a UHV DC and AC combined system the UHVDC’s blocking fault becomes the most serious load balance contingency of the receiving end power system due to its large capacity.The amount of contingency reserve thus is la...In a UHV DC and AC combined system the UHVDC’s blocking fault becomes the most serious load balance contingency of the receiving end power system due to its large capacity.The amount of contingency reserve thus is largely increased.This paper proposes three distinct schemes for allocating contingency reserve to cover the power shortage caused by UHVDC’s blocking fault,and compares the economic cost of these schemes.An operation simulation method using a unit commitment technique is proposed for evaluating the operation costs associated with increasing contingency reserve.A real case study for a Jiangsu Province power system in China is presented to demonstrate that the best scheme is to share the contingency reserve with neighborhood power systems through the transmission capacity of UHVAC lines.展开更多
In recent years, cloud sync(hronization) services such as GoogleDrive and Dropbox have provided Internet users with convenient and reliable data storing/sharing functionality. The cloud synchronization mechanism (i...In recent years, cloud sync(hronization) services such as GoogleDrive and Dropbox have provided Internet users with convenient and reliable data storing/sharing functionality. The cloud synchronization mechanism (in particular, how to deliver the user-side data updates to the cloud) plays a critical role in cloud sync services because it greatly affects the cloud operation cost (in terms of sync traffic) and user experience (in terms of sync delay). By comprehensively measuring tens of popular cloud sync services, we find that their cloud sync mechanisms differ greatly in sync performance and design granularity. Quite surprisingly, some very popular services (like GoogleDrive and 115 SyncDisk) utilize a quite coarse-grained cloud sync mechanism that may lead to severe traffic overuse. For example, updating 1-MB data may sometimes result in 260-MB sync traffic. In this paper, we conduct a comparative study of various cloud sync mechanisms by analyzing their respective pros and cons under different situations, unravel the pathological processes for their traffic overuse problems, and finally provide insights/solutions for better choosing/designing a cloud sync service.展开更多
文摘The adoption of new technologies often represents a crucial component of firms' investment decisions. This paper studies a dynamic duopoly model in which two firms compete in adoption of current technology with a further new technology anticipated. Here it is assumed that the operating costs are not zero which has more explanatory power of the real world. There exist three kinds of equilibria that may occur in adoption of current technology, which mainly depends on the level of operating costs and the first-move advantage. It shows that the faster technological substitution or innovation encourages the leader to invest earlier while induces the follower to invest later. Furthermore,like the investment costs,with the increase of operating costs the follower tends to invest later while the leader tends to invest earlier ,the investment thresholds are more sensitive to the change of operating costs than that of investment costs.
文摘The purpose of this paper is to approach the administrative costs in the field of education and to answer questions such as:How are administrative costs measured and evaluated?Is it taken into account in the analysis of policy options?Administrative costs affect all areas of public education and absorb a large part of the state budget appropriations intended for education.Through the presentation of the general and specific objectives but also the European participation in the rational management of the management costs of the educational units,we lead to a holistic approach to the operational costs of the education that is part of the social costs.
文摘The application of floating photovoltaics (PVs) in hydropower plants has gained increasing interest in forming hybrid energy systems (HESs). It enhances the operational benefits of the existing hydropower plants. However, uncertainties of PV and load powers can present great challenges to scheduling HESs. To address these uncertainties, this paper proposes a novel two-stage optimization approach that combines distributionally robust chance-constrained (DRCC) and robust-stochastic optimization (RSO) approaches to minimize the operational cost of an HES. In the first stage, the scheduling of each device is obtained via the DRCC approach considering the PV power and load forecast errors. The second stage provides a robust near real time energy dispatch according to different scenarios of PV power and load demand. The solution of the RSO problem is obtained via a novel double-layer particle swarm optimization algorithm. The performance of the proposed approach is compared to the traditional stochastic and robust-stochastic approaches. Simulation results de- monstrate the superiority of the proposed two-stage approach and its solution method in terms of operational cost and execution time.
文摘目的对经外周置入中心静脉导管(peripherally inserted central catheter,PICC)置管、维护及拔管的单项操作成本进行核算,为制定合理的操作收费价格提供依据。方法通过横断面调查,采用项目成本阶梯分摊法,于2019年1—5月在复旦大学附属肿瘤医院血管通路门诊测算PICC各单项操作人力成本、设备折旧费及未单独计价材料费,测算直接成本,并通过分摊测算间接成本,最后测算PICC置管、维护及拔管的单项操作成本。结果PICC置管、维护及拔管的各单项操作实际成本分别为(157.03±4.73)元、(33.66±3.04)元、(32.38±3.11)元,与上海市医疗机构对PICC各项操作的收费标准(分别为150元、30元、30元)基本相符。结论建议将PICC维护及拔管的操作收费纳入收费标准中,促进PICC输液技术的可持续发展并确保护理服务的持续供给。
文摘We apply the simplex algorithm which is a branch of linear programming to efficiently determine the allocation of resources required to operate a company in the software development field. The main aim of applying this technique is to maximize the profit of a company under certain limitations. This <span>can be done using the trial-and-error approach. However, this tedious</span> process can be replaced by user-level tools such as Excel which are based on linear programming that will give more accurate results. Small software companies cannot afford to hire a high number of senior programmers to produce the required level of quality and to keep up with the demand for adding new features. On the other hand, lowering the quality of the product will reduce the number of customers and decrease profit. Another aspect is maximizing the utilization of hosting servers which are required for providing the services to customers since the cost of buying servers and maintaining them is extremely high. The simplex algorithm in linear programming will take the specified <span>constraints into account to compute the optimal allocation of the available</span> <span>resources to maximize profit and limit the cost. This paper will present a</span> <span>model that uses the simplex algorithm with a set of constraints to determine</span> how many projects of each type a company should take in one period of time.
基金the supports provided by National Iranian Oil Engineering and Construction Company(NIOEC)。
文摘A continuous-flow ultrasound-assisted oxidative desulfurization(UAOD)of partially hydro-treated diesel has been investigated using hydrogen peroxide-formic acid as simple and easy to apply oxidation system.The effects of different operating parameters of oxidation stage including residence time(2–24 min),formic acid to sulfur molar ratio(10–150),and oxidant to sulfur molar ratio(5–35)on the sulfur removal have been studied using response surface methodology(RSM)based on Box–Behnken design.Considering the operating costs of the continuous-flow oxidation stage including chemical and electrical energy consumption,the appropriate values of operating parameters were selected as follows:residence time of 16 min,the formic acid to sulfur molar ratio of 54.47,and the oxidant to sulfur molar ratio of 8.24.In these conditions,the sulfur removal and the volume ratio of the hydrocarbon phase to the aqueous phase were 86.90%and 4.34,respectively.By drastic reduction in the chemical consumption in the oxidation stage,the volume ratio of the hydrocarbon phase to the aqueous phase was increased up to 10.Therefore,the formic acid to sulfur molar ratio and the oxidant to sulfur molar ratio were obtained 23.64 and 3.58,respectively,which lead to sulfur removal of 84.38%with considerable improvements on the operating cost of oxidation stage in comparison with the previous works.
基金Supported by National Natural Science Foundation of China(No.20106008)China Postdoctoral Science Foundation,Tsinghua University-Zhongda Group Postdoctoral Science Foundationthe National Environmental Protect Bureau of China(Huan-Ke-Ke,1997,
文摘Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mixture is explored. An evaluating method is proposed, and the pertinent optimization model is then derived. The ethanol-water system is studied as an illustrative example. The optimization results show that the maximum energy saving in ITCDIC process is about 35% and the maximum operating cost saving in ITCDIC process is about 30%,as compared with a conventional distillation column(CDIC) under the minimum reflux ratio operating; the optimal operating pressure of the rectifying section is found to be around 0.25 MPa; the effects of the feed composition,operating pressure and the heat transfer rate on operation are also found and analyzed. It is revealed that ITCDIC process possesses high energy saving potential and promising economical prospect.
基金Supported by National Natural Science Foundation of China(Grant No.11072192)Shaanxi Provincial Industrial Technology Research Projects of China(Grant No.2015GY118)
文摘The beer game model is a typical paradigm used to study complex dynamics behaviours in production–distribution systems. The model, however, does not accord with current practical supply chain system models in discrete?type manufacturing industry, which are generally composed of retailers, distributors, manufacturers with internal sup?ply chain, and suppliers. To describe how ordering policies influence the complex dynamics behaviour modes and operating cost in a general discrete?type manufacturing industry supply chain system, a high dimension piecewise?linear dynamics model is built for the supply chain system. Five kinds of ordering policy combination are considered. The distribution of both the largest Lyapunov exponent of e ective inventory and average operating cost per cycle is obtained by simulation in a policy space. The simulation shows that for the general discrete?type manufacturing industry supply chain system, the upper chaotic corners emerge besides the lower chaotic corners in the policy space expressing the distribution of system behaviour mode, and that the ordering policies at each supply chain node as well as their combination have very significant e ect on the topology of the distribution of both system behaviour mode and operating cost in the policy space. We find that chaos is not always corresponding to high cost, and the "chaos amplification" is not completely relevant to the "cost amplification".
基金Sponsored by the Ministerial Level Foundation(20021823)
文摘Based on the analysis of inherent limitations in existing security response decision-making systems, a dynamic adaptive model of fault response is presented. Several security fault levels were founded, which comprise the basic level, equipment level and mechanism level. Fault damage cost is calculated using the analytic hierarchy process. Meanwhile, the model evaluates the impact of different responses upon fault repair and normal operation. Response operation cost and response negative cost are introduced through quantitative calculation. This model adopts a comprehensive response decision of security fault in three principles--the maximum and minimum principle, timeliness principle, acquiescence principle, which assure optimal response counter- measure is selected for different situations. Experimental results show that the proposed model has good self- adaptation ability, timeliness and cost-sensitiveness.
基金Project Supported by National Natural Science Foundation of China(51777193).
文摘The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will greatly deepen the coupling of the electricity-gas integrated energy system,improve the flexibility and safety of the operation of the power system,and bring a deal of benefits to the power system.On this background,an optimal dispatch model of RIES combined cold,heat,gas and electricity with SOP is proposed.Firstly,RIES architecture with SOP and P2G is designed and its mathematical model also is built.Secondly,on the basis of considering the optimal scheduling of combined cold,heat,gas and electricity,the optimal scheduling model for RIES was established.After that,the original model is transformed into a mixed-integer second-order cone programming model by using linearization and second-order cone relaxation techniques,and the CPLEX solver is invoked to solve the optimization problem.Finally,the modified IEEE 33-bus systemis used to analyze the benefits of SOP,P2G technology and lithium bromide absorption chillers in reducing systemnetwork loss and cost,as well as improving the system’s ability to absorb wind and solar and operating safety.
文摘Since July 2014,when the international oil price slumped,the upstream sector of global oil and gas industry has experienced a tough transformation phase lasting over two years.In terms of the development trend,the global upstream sector has demonstrated six characteristics since 2017:firstly,global upstream investment will probably demonstrate the trend of "touching the ground and rising again";secondly,upstream operating costs will continually decline;thirdly,more favorable finance and taxation clauses will be offered for some resources to be developed through foreign cooperation;fourthly,global oil and gas output will probably further increase;fifthly,upstream exploration efficiency is anticipated to steadily increase;and sixthly,upstream geological understandings,theory and technology will continue to advance.In accordance with the above-mentioned development trends,Chinese oil enterprises must be prepared in four aspects for future rejuvenation.Firstly,persistent upstream investment has to be guaranteed,particularly in the exploration field;secondly,upstream operation efficiency must be promoted through the enhancement of technical research;thirdly,overseas upstream property must be purchased within the "time window";and fourthly,reforms have to be carried out to realize transformation in the petroleum industry.
文摘Treatment of Indigo dye (leuco form), reduced in the industrial conditions of the SITEX (Textile Industrial Company), by a batch electrocoagulation using aluminum electrodes. Response Surface Methodology (RSM) and Box-Behnken design were used to optimize for Color Removal (CR(%)). Our results showed that the quadratic second order equation provided the best correlation for the decolorization of Indigo dye (CR(%)). On the other hand, the ANOVA analysis proved the large interaction between the current intensity and the initial concentration of the dye. Experiments were conducted to find the desired conditions for removal of particular concentration of the dye and lower Operation Cost. The results showed that CR(%) = 88.3% (R<sup>2</sup>) of color removal for initial dye concentration of 12.31 mg/l, with a current density of 2.81 A/m<sup>2</sup>, solution concentration of NaCl of 2.67 g/l. Under these conditions, Electrical Energy Consumption (EEC) and Electrode Consumption (EMC) and Operation Cost were 0.01999 kWh/m<sup>3</sup> (R<sup>2</sup> = 93.1%), 0.00142768 Kg/m<sup>3</sup> (R<sup>2</sup> = 79.4%) and 0.000558 US$/m<sup>3</sup>, respectively.
基金the National Science Foundation of China(52207080)in part by the State Grid Jiangsu Electric Power Company Science and Technology Project(J2020001)in part by the National Science Foundation of Jiangsu Province(BK20200404).
文摘The operational stability and economy of multi-energy systems(MES)are threatened by various uncertainties,such as variable renewable energy power,energy demands,and weather conditions.Most of the existing methods for the dispatch decisions of MES are based on the prescribed probability distribution or uncertainty sets of random variables,which have many disadvantages,such as potential infeasibility and over-conservatism.In this paper,we propose a novel dispatch model for MES that integrates dispatch decision making,uncertainty set selection,and operational cost control into a unified framework.First,the deterministic dispatch model of MES is introduced,in which the physical characteristics of district heating systems and buildings are fully considered.Then,a novel decision framework that combines the two-stage dispatch strategy and info-gap decision theory(IGDT)is proposed for MES,where the uncertainty set is flexible and can be optimized based on the operational cost budget.Finally,a revised algorithm,based on the column-and-constraint generation method,is proposed for the model.Case studies are performed on MES that includes a 33-bus distribution system and a heating network modified from a real 51-node network located in Jinlin Province,China.The results verify the effectiveness of the proposed method.
基金supported in part by the Research Project of Digital Grid Research Institute,China Southern Power Grid(No.YTYZW20010)in part by the Research and Development Program Project in Key Areas of Guangdong Province(No.2021B0101230003)in part by the National Natural Science Foundation of China(No.51907031)。
文摘In the electricity market environment,the regional integrated energy system(RIES)can reduce the total operation cost by participating in electricity market transactions.However,the RIES will face the risk of load and electricity price uncertainties,which may make its operation cost higher than expected.This paper proposes a method to optimize the operation cost of the RIES in the electricity market environment considering uncertainty.Firstly,based on the operation cost structure of the RIES in the electricity market environment,the energy flow relationship of the RIES is analyzed,and the operation cost model of the RIES is built.Then,the electricity purchase costs of the RIES in the medium-and long-term electricity markets,the spot electricity market,and the retail electricity market are analyzed.Finally,considering the risk of load and electricity price uncertainties,the operation cost optimization model of the RIES is established based on conditional value-at-risk.Then it is solved to obtain the operation cost optimization strategy of the RIES.Verification results show that the proposed operation cost optimization method can reduce the operation cost of high electricity price scenario by optimizing the energy purchase and distribution strategy,constrain the risk of load and electricity price uncertainties,and help balance the risks and benefits.
文摘Based on the value function of the prospect theory,this paper constructs a security function,which is used to describe the victims’feelings about the distance in emergency evacuation.Since different paths between the demand points and the emergency shelters are generally of different importance degrees,they are divided into main paths and auxiliary paths.The security function values and the reliability levels of main paths and auxiliary paths are given different weights.The weighted sum of the security function values and the weighted sum of the reliability level function values of all demand points are maximized to determine the location and the number of the emergency shelters,the transfer paths,the reinforced edges and the incremental reliability level of the selected edge.In order to solve the model,a two-stage simulated annealing-particle swarm optimization algorithm is proposed.In this algorithm,the particle swarm optimization(PSO)algorithm is embedded into the simulated annealing(SA)algorithm.The cumulative probability operator and the cost probability operator are formed to determine the evolution of the particles.Considering the budget constraint,the algorithm eliminates the shelter combinations that do not meet the constraint,which greatly saves the calculation time and improves the efficiency.The proposed algorithm is applied to a case,which verifies its feasibility and stability.The model and the algorithm of this paper provide a basis for emergency management departments to make the earthquake emergency planning.
基金supported by the Fundamental Research Funds for the Central Universities (NUAA NN2012071)China Postdoctoral Science Foundation (2011M500919)
文摘Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requirement for aircraft design. In this paper, estimation method for emis- sion in aircraft conceptual design stage is improved based on the International Civil Aviation Orga- nization (ICAO) aircraft engine emissions databank and the polynomial curve fitting methods. The greenhouse gas emission (CO2 equivalent) per seat per kilometer is proposed to measure the emis- sions. An approximate sensitive analysis and a multi-objective optimization of aircraft design for tradeoff between greenhouse effect and direct operating cost (DOC) are performed with five geom- etry variables of wing configuration and two flight operational parameters. The results indicate that reducing the cruise altitude and Mach number may result in a decrease of the greenhouse effect but an increase of DOC. And the two flight operational parameters have more effects on the emissions than the wing configuration. The Pareto-optimal front shows that a decrease of 29.8% in DOC is attained at the expense of an increase of 10.8% in greenhouse gases.
基金supported by the National Natural Science Foundation of China (NSFC) under Grant Nos. 60872120, 60902078, 61172104the Natural Science Foundation of Beijing under Grant No. 4112061+2 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars of State Education Ministry of Chinathe French System@tic Paris-Region (CSDL Project)the National Agency for Research of French (ANR)-NSFC under Grant No. 60911130368
文摘Current multi-operator image resizing methods succeed in generating impressive results by using image similarity measure to guide the resizing process. An optimal operation path is found in the resizing space. However, their slow resizing speed caused by inefficient computation strategy of the bidirectional patch matching becomes a drawback in practical use. In this paper, we present a novel method to address this problem. By combining seam carving with scaling and cropping, our method can realize content-aware image resizing very fast. We define cost functions combing image energy and dominant color descriptor for all the operators to evaluate the damage to both local image content and global visual effect. Therefore our algorithm can automatically find an optimal sequence of operations to resize the image by using dynamic programming or greedy algorithm. We also extend our algorithm to indirect image resizing which can protect the aspect ratio of the dominant object in an image.
基金supported by National Natural Science Foundation of China(No.51325702)Science-Technology Project of State Grid Corporation of China(No.GHJS1500009)State Grid Excellent Innovation Foundation of Tsinghua University(No.2011079).
文摘In a UHV DC and AC combined system the UHVDC’s blocking fault becomes the most serious load balance contingency of the receiving end power system due to its large capacity.The amount of contingency reserve thus is largely increased.This paper proposes three distinct schemes for allocating contingency reserve to cover the power shortage caused by UHVDC’s blocking fault,and compares the economic cost of these schemes.An operation simulation method using a unit commitment technique is proposed for evaluating the operation costs associated with increasing contingency reserve.A real case study for a Jiangsu Province power system in China is presented to demonstrate that the best scheme is to share the contingency reserve with neighborhood power systems through the transmission capacity of UHVAC lines.
基金supported in part by the National Natural Science Foundation of China (No. 61073015)the National Key Basic Research and Development (973) Program of China (No. 2011CB302305)National Key Projects of Science and Technology of China (No.2010ZX03004-001-03)
文摘In recent years, cloud sync(hronization) services such as GoogleDrive and Dropbox have provided Internet users with convenient and reliable data storing/sharing functionality. The cloud synchronization mechanism (in particular, how to deliver the user-side data updates to the cloud) plays a critical role in cloud sync services because it greatly affects the cloud operation cost (in terms of sync traffic) and user experience (in terms of sync delay). By comprehensively measuring tens of popular cloud sync services, we find that their cloud sync mechanisms differ greatly in sync performance and design granularity. Quite surprisingly, some very popular services (like GoogleDrive and 115 SyncDisk) utilize a quite coarse-grained cloud sync mechanism that may lead to severe traffic overuse. For example, updating 1-MB data may sometimes result in 260-MB sync traffic. In this paper, we conduct a comparative study of various cloud sync mechanisms by analyzing their respective pros and cons under different situations, unravel the pathological processes for their traffic overuse problems, and finally provide insights/solutions for better choosing/designing a cloud sync service.