The dynamic model of the ball screw mechanism(BSM)in spatial motion,developed in Part I of the study titled‘research and experimental analysis on precision degradation of BSM at low speed’,has been validated through...The dynamic model of the ball screw mechanism(BSM)in spatial motion,developed in Part I of the study titled‘research and experimental analysis on precision degradation of BSM at low speed’,has been validated through a comparison between calculated values and experimentally measured data obtained from a comprehensive ball-screw test bench.In order to study the perform-ance parameters related to the precision degradation characteristics of ball screw under different pre-loads and speeds,the precision degradation test bench for ball screw is set up.Through the experi-ment on the ball-screw comprehensive test bench,the drag torque,stroke deviation,acceleration peak value,axial contact stiffness and other parameters of the BSM under different speeds are ob-tained,and the different preloads are obtained by the drag torque,the changing regularity of which is consistent with the simulation results.A comprehensive analysis of the experimental data reveals that the dynamic characteristics of the ball screw’s spatial motion are significantly influenced by gy-roscopic torque effects.By incorporating these parametric effects,the accuracy degradation charac-teristics of ball screw under different preloads and speeds can be well analyzed.This methodology establishes a technical foundation for investigating ball screw accuracy retention characteristics.展开更多
Considering the uncertainty of the speed of horizontal transportation equipment,a cooperative scheduling model of multiple equipment resources in the automated container terminal was constructed to minimize the comple...Considering the uncertainty of the speed of horizontal transportation equipment,a cooperative scheduling model of multiple equipment resources in the automated container terminal was constructed to minimize the completion time,thus improving the loading and unloading efficiencies of automated container terminals.The proposed model integrated the two loading and unloading processes of“double-trolley quay crane+AGV+ARMG”and“single-trolley quay crane+container truck+ARMG”and then designed the simulated annealing particle swarm algorithm to solve the model.By comparing the results of the particle swarm algorithm and genetic algorithm,the algorithm designed in this paper could effectively improve the global and local space search capability of finding the optimal solution.Furthermore,the results showed that the proposed method of collaborative scheduling of multiple equipment resources in automated terminals considering hybrid processes effectively improved the loading and unloading efficiencies of automated container terminals.The findings of this study provide a reference for the improvement of loading and unloading processes as well as coordinated scheduling in automated terminals.展开更多
The overall performance of multi-robot collaborative systems is significantly affected by the multi-robot task allocation.To improve the effectiveness,robustness,and safety of multi-robot collaborative systems,a multi...The overall performance of multi-robot collaborative systems is significantly affected by the multi-robot task allocation.To improve the effectiveness,robustness,and safety of multi-robot collaborative systems,a multimodal multi-objective evolutionary algorithm based on deep reinforcement learning is proposed in this paper.The improved multimodal multi-objective evolutionary algorithm is used to solve multi-robot task allo-cation problems.Moreover,a deep reinforcement learning strategy is used in the last generation to provide a high-quality path for each assigned robot via an end-to-end manner.Comparisons with three popular multimodal multi-objective evolutionary algorithms on three different scenarios of multi-robot task allocation problems are carried out to verify the performance of the proposed algorithm.The experimental test results show that the proposed algorithm can generate sufficient equivalent schemes to improve the availability and robustness of multi-robot collaborative systems in uncertain environments,and also produce the best scheme to improve the overall task execution efficiency of multi-robot collaborative systems.展开更多
With the rapid development of modern agriculture,the prevention and control of crop diseases and insect pests has become an important part to ensure the safety of agricultural production,the quality of agricultural pr...With the rapid development of modern agriculture,the prevention and control of crop diseases and insect pests has become an important part to ensure the safety of agricultural production,the quality of agricultural products and the safety of agricultural ecological environment.Although the effect of traditional chemical prevention and control technology is remarkable,the health risks and environmental problems brought by it should not be ignored.As a green and environmentally friendly means of prevention and control,biological prevention and control technology has gradually become a hot research topic and a trend of agricultural production.This paper is intended to comprehensively evaluate the social costs of biological control technologies for crop diseases and pests,including the health risks reduced,environmental improvements,economic benefits,and barriers to promotion,and put forward corresponding policy recommendations.展开更多
In the field of biological control of agricultural and forestry pests,natural enemy insects play an important role,constituting the core of modern integrated pest management(IPM)strategy,providing solid support for th...In the field of biological control of agricultural and forestry pests,natural enemy insects play an important role,constituting the core of modern integrated pest management(IPM)strategy,providing solid support for the zero growth goal of chemical pesticide use,and helping the sustainable development of green agriculture.The rise of the natural enemy insect industry has become a key driver of the transformation of green agriculture,injecting vitality into the sustainability and ecological protection of agriculture.With the increasing concern about food safety,environmental protection and ecological balance all over the world,the application scope of natural enemy insects as biological control means is constantly expanding.Its unique ecological adaptability and environmentally friendly characteristics help to reduce dependence on chemical pesticides,ensure the safety of agricultural products and maintain ecological diversity.The purpose of this study is to analyze the current situation of natural enemy insect industry,evaluate its cost and benefit,emphasize its great significance in promoting the transformation of green agriculture,improving production efficiency and promoting ecological protection by drawing lessons from foreign successful experiences,and explore an efficient and sustainable new agricultural development model.展开更多
Maintaining population diversity is an important task in the multimodal multi-objective optimization.Although the zoning search(ZS)can improve the diversity in the decision space,assigning the same computational costs...Maintaining population diversity is an important task in the multimodal multi-objective optimization.Although the zoning search(ZS)can improve the diversity in the decision space,assigning the same computational costs to each search subspace may be wasteful when computational resources are limited,especially on imbalanced problems.To alleviate the above-mentioned issue,a zoning search with adaptive resource allocating(ZS-ARA)method is proposed in the current study.In the proposed ZS-ARA,the entire search space is divided into many subspaces to preserve the diversity in the decision space and to reduce the problem complexity.Moreover,the computational resources can be automatically allocated among all the subspaces.The ZS-ARA is compared with seven algorithms on two different types of multimodal multi-objective problems(MMOPs),namely,balanced and imbalanced MMOPs.The results indicate that,similarly to the ZS,the ZS-ARA achieves high performance with the balanced MMOPs.Also,it can greatly assist a“regular”algorithm in improving its performance on the imbalanced MMOPs,and is capable of allocating the limited computational resources dynamically.展开更多
This paper proposes an improved cellular automaton model to describe the urban traffic flow with the consideration of traffic light and driving behaviour effects. Based on the model, the characteristics of the urban t...This paper proposes an improved cellular automaton model to describe the urban traffic flow with the consideration of traffic light and driving behaviour effects. Based on the model, the characteristics of the urban traffic flow on a single- lane road are investigated under three different control strategies, i.e., the synchronized, the green wave and the random strategies. The fundamental diagrams and time-space patterns of the traffic flows are provided for these strategies respectively. It finds that the dynamical transition to the congested flow appears when the vehicle density is higher than a critical level. The saturated flow is less dependent on the cycle time and the strategies of the traffic light control, while the critical vehicle density varies with the cycle time and the strategies. Simulated results indicate that the green wave strategy is proven to be the most effective one among the above three control strategies.展开更多
As a synthetic functional analog of salicylic acid, 2,6-dichloroisonicotinic acid(INA) is effective in inducing the host disease resistance of a plant against a pathogen. The effects of INA on controlling postharvest ...As a synthetic functional analog of salicylic acid, 2,6-dichloroisonicotinic acid(INA) is effective in inducing the host disease resistance of a plant against a pathogen. The effects of INA on controlling postharvest blue and green molds and anthracnose decay and defense-related enzymes on citrus fruits were investigated, and the ascorbic acid of naturally infected citrus flavedo was also measured. Results showed that 1.0 mmol L^(–1) INA treatments significantly reduced blue and green molds and anthracnose decay development on both wound-inoculated fruit and naturally-infected fruit compared with the control fruit. The treatment effectively enhanced the β-1,3-glucanase(GLU), chitinase(CHI), phenylalanine ammonia-lyase(PAL) and peroxidase(POD) activities and the polyphenol oxidase(PPO) in flavedo. The results presented here suggest that INA might be used as a chemical fungicide substitution to control postharvest diseases in citrus fruits.展开更多
The throughput capacity of a container terminal is very important in planning and designing at container terminals.The existing methods estimated the throughput capacity without considering its change resulting from t...The throughput capacity of a container terminal is very important in planning and designing at container terminals.The existing methods estimated the throughput capacity without considering its change resulting from the different combination patterns of the types of arriving vessels.A simulation model is established to estimate the throughput capacities of a container terminal under different combination patterns of the types of arriving vessels.It shows that the throughput capacity of a container terminal is influenced by the utilization rates of the berth and quay cranes which result from the different combination patterns of the types of the arriving vessels.It provides a practical approach to estimate the throughput capacity of a container terminal considering the types of the vessels,and it is also helpful for the decision makers to raise the throughputs of the container terminals by optimizing the combination patterns of the types of arriving vessels.展开更多
In this paper, a cellular automaton model considering game strategy update is proposed to study the pedestrian evac- uation in a hall. Pedestrians are classified into two categories, i.e., cooperators and defectors, a...In this paper, a cellular automaton model considering game strategy update is proposed to study the pedestrian evac- uation in a hall. Pedestrians are classified into two categories, i.e., cooperators and defectors, and they walk to an exit according to their own strategy change. The conflicts that two or three pedestrians try to occupy the same site at the same time are investigated in the Game theory model. Based on it, the relationship between the pedestrian flow rate and the evacuation time as well as the variation of cooperative proportion against evacuation time is investigated from the different initial cooperative proportions under the influence of noise. The critical value of the noise is found when there is a small number of defectors in the initial time. Moreover, the influences of the initial cooperative proportion and strength of noise on evacuation are discussed. The results show that the lower the initial cooperative proportion as well as the bigger the strength of noise, the longer the time it takes for evacuation.展开更多
Secure storage yard is one of the optimal core goals of container transportation;thus,making the necessary storage arrangements has become the most crucial part of the container terminal management systems（CTMS）.Thi...Secure storage yard is one of the optimal core goals of container transportation;thus,making the necessary storage arrangements has become the most crucial part of the container terminal management systems（CTMS）.This paper investigates a random hybrid stacking algorithm（RHSA） for outbound containers that randomly enter the yard.In the first stage of RHSA,the distribution among blocks was analyzed with respect to the utilization ratio.In the second stage,the optimization of bay configuration was carried out by using the hybrid genetic algorithm.Moreover,an experiment was performed to test the RHSA.The results show that the explored algorithm is useful to increase the efficiency.展开更多
The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection functi...The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection function,which enables multiplex PCR reaction.In this study,this technique was used to establish triple dPCR detection for the genetically modified soybean MON87708 × MON89788 with stacked traits.Specific absolute quantitative detection was accomplished for the genomic DNA extracted from the homogenized seeds of GM stack MON87708× MON89788 soybean.Our results can serve as a reference for the absolute quantitative detection of stacked events of genetically modified crops.展开更多
As online trade and interactions on the internet are on the rise, a key issue is how to use simple and effective evaluation methods to accomplish trust decision-making for customers. It is well known that subjective t...As online trade and interactions on the internet are on the rise, a key issue is how to use simple and effective evaluation methods to accomplish trust decision-making for customers. It is well known that subjective trust holds uncertainty like randomness and fuzziness. However, existing approaches which are commonly based on probability or fuzzy set theory can not attach enough importance to uncertainty. To remedy this problem, a new quantifiable subjective trust evaluation approach is proposed based on the cloud model. Subjective trust is modeled with cloud model in the evaluation approach, and expected value and hyper-entropy of the subjective cloud is used to evaluate the reputation of trust objects. Our experimental data shows that the method can effectively support subjective trust decisions and provide a helpful exploitation for subjective trust evaluation.展开更多
Jujube fruits usually suffer from physiological disorders or infectious diseases during storage,leading to quality deterioration,softening,or rotting.Therefore,this study aims to investigate the effect of methionine s...Jujube fruits usually suffer from physiological disorders or infectious diseases during storage,leading to quality deterioration,softening,or rotting.Therefore,this study aims to investigate the effect of methionine soaking treatment on the postharvest jujube fruit decay rate and storage quality.Methionine treatment significantly reduced the decay rate of postharvest jujube fruit and effectively maintained fruit color and titratable acid.Methionine treatment effectively delayed the decrease of firmness,soluble solids,ascorbic acid,and lignin contents in jujube fruit.Methionine treatment reduced the content of alanine and phenylalanine,and increased the content of glycine in jujube fruit,but displayed no significant effect on total amino acid content.In addition,jujube fruits in the methionine treatment group had a higher total phenolic and flavonoid content and antioxidant capacity,both in free and bound forms.Compared with the control,methionine treatment also significantly increased the content of individual phenolic acid fractions(gallic acid,vanillic acid,and syringic acid)and flavonoid fractions(catechin,epicatechin,rutin)in free form as well as individual phenolic acid fractions in bound form(gallic acid and ferulic acid)in jujube fruits.Overall,this study suggested that the methionine treatment could be used as a prospective preservative to reduce the postharvest decay of jujube fruit and alleviate its nutritional quality deterioration during cold storage at 4°C.展开更多
Expert system plays an important role in port machine diagnosis, which aims at automatic equipment test for higher availability and efficiency of port operations. In this study, a port machine diagnosis expert system ...Expert system plays an important role in port machine diagnosis, which aims at automatic equipment test for higher availability and efficiency of port operations. In this study, a port machine diagnosis expert system is proposed based on multi-reasoning mechanism. Relying on the knowledge acquired from the experienced experts in the port machine engineering, the system builds a library of relative experience and a set of rules of reasoning and estimating. Multi-reasoning mechanism that simulates the decision-making process of domain experts is employed to achieve reliable diagnosis results. The reasoning machine integrates artificial neural network, uncertain decision making and decision tree, which complements each other by sustainable growing voting mechanism. The effect of this multi-reasoning mechanism is evaluated and validated by means of Matthew＇s Correlation Coefficient （MCC）. The system incorporating the mechanism is successfully designed, implemented and applied in Shanghai Port.展开更多
This paper is on the suggestion of maintenance items for electric railway facility systems.With the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility sys...This paper is on the suggestion of maintenance items for electric railway facility systems.With the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility systems are also increasing,but the railroad electrical facility system in Korea is rapidly aging.To solve this problem,various methodologies are applied to ensure operational reliability and stability for railroad electrical facility systems,but there is a lack of detailed evaluation criteria for railroad electrical facility system maintenance.Also,maintenance items must be selected in a scientific and systematic method.Therefore,railroad electrical facility systems are selected for study.Design StructureMatrix(DSM)is utilized to establish considerations tailored to the maintenance characteristics,and the Fuzzy-TOPSIS methodology is utilized for determining the maintenance detail evaluation item baseline weights,a multi-criteria decision-making problem.Studies show that degradation,insulation items have the highest weight of 14.63%,and capacity items have the lowest weight of 5.34%.The results of this may be contributed to the underlying research in carrying out maintenance activities to ensure the reliability and safety of railroad electrical facility systems.展开更多
Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma dur...Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time.However,the influence of growth stages on the volatile compounds in Jincheng orange remains unclear.In addition,volatiles originate from fatty acids,most of which are the precursors of volatile substances.On this basis,gas chromatography-mass spectrometry(GC-MS)was performed to elaborate the changes in volatile constituents and fatty acids as precursors.This study tested proximately 60 volatiles and 8 fatty acids at 9 growth and development stages(AF1-AF9).Of those compounds,more than 92.00%of total volatiles and 87.50%of fatty acids were terpenoid and saturated fatty acids,respectively.As shown in the PCA plot,the AF5,AF6,and AF9 stages were confirmed as completely segregated and appeared different.In addition,most of the volatiles and fatty acids first increased at the beginning of the development stage,then decreased from the AF6 development stage,and finally increased at the AF9 maturity stage.Moreover,the highest contents of terpenoid,alcohols,aldehydes,ketones,and saturated fatty acids in Jincheng orange peel oil were d-limonene,linalool,octanal,cyclohexanone,and stearic acid during development stages,respectively.Our results found that the growth stages significantly affected the volatile constituents and precursors in Jincheng orange peel oil.展开更多
The search efficiency of differential evolution （DE） algorithm is greatly impacted by its control parameters. Although many adaptation/self-adaptation techniques can automatically find suitable control parameters fo...The search efficiency of differential evolution （DE） algorithm is greatly impacted by its control parameters. Although many adaptation/self-adaptation techniques can automatically find suitable control parameters for the DE, most techniques are based on pop- ulation information which may be misleading in solving complex optimization problems. Therefore, a self-adaptive DE （i.e., JADE） using two-phase parameter control scheme （TPC-JADE） is proposed to enhance the performance of DE in the current study. In the TPC-JADE, an adaptation technique is utilized to generate the control parameters in the early population evolution, and a well-known empirical guideline is used to update the control parameters in the later evolution stages. The TPC-JADE is compared with four state-of-the-art DE variants on two famous test suites （i.e., IEEE CEC2005 and IEEE CEC2015）. Results indicate that the overall performance of the TPC-JADE is better than that of the other compared algorithms. In addition, the proposed algorithm is utilized to obtain optimal nutrient and inducer feeding for the Lee-Ramirez bioreactor. Experimental results show that the TPC-JADE can perform well on an actual dynamic optimization problem.展开更多
A dynamic pricing model was established based on forecasting the demand for container handling of a specific shipping company to maximize terminal profits to solve terminal handling charges under the changing market e...A dynamic pricing model was established based on forecasting the demand for container handling of a specific shipping company to maximize terminal profits to solve terminal handling charges under the changing market environment.It assumes that container handling demand depends on the price and the unknown parameters in the demand model.The maximum quasi-likelihood estimation(MQLE)method is used to estimate the unknown parameters.Then an adaptive dynamic pricing policy algorithm is proposed.At the beginning of each period,through dynamic pricing,determining the optimal price relative to the estimation value of the current parameter and attach a constraint of differential price decision.Meanwhile,the accuracy of demand estimation and the optimality of price decisions are balanced.Finally,a case study is given based on the real data of Shanghai port.The results show that this pricing policy can make the handling price converge to the stable price and significantly increase this shipping company’s handling profit compared with the original“contractual pricing”mechanism.展开更多
This paper reports a study concerning occurrence and growth of traffic jam in a harbor tunnel. The single-lane with three sections （downgrade, fiat, and upgrade） is taken into account and they are characterized with...This paper reports a study concerning occurrence and growth of traffic jam in a harbor tunnel. The single-lane with three sections （downgrade, fiat, and upgrade） is taken into account and they are characterized with different velocity limit. At the low density, the traffic current increases linearly with density and saturates at some values of immediately density. As the density increases, the traffic jam appears firstly before the upgrade section and then extends to the downgrade section. Additionally, the relationships of the velocity and headway against position in different densities are obta/ned from simulation. These results clearly clarify where and when the traffic jam appears. Finally, the critical densities are derived via the theoretical analysis before and after the discontinuous fronts and the theoretical results are consistent with the critical values of simulation results.展开更多
基金Supported by the National Natural Science Foundation of China(No.51575014,51505020)the Key Foundation Project of China Academy of Railway Sciences(No.2021YJ200).
文摘The dynamic model of the ball screw mechanism(BSM)in spatial motion,developed in Part I of the study titled‘research and experimental analysis on precision degradation of BSM at low speed’,has been validated through a comparison between calculated values and experimentally measured data obtained from a comprehensive ball-screw test bench.In order to study the perform-ance parameters related to the precision degradation characteristics of ball screw under different pre-loads and speeds,the precision degradation test bench for ball screw is set up.Through the experi-ment on the ball-screw comprehensive test bench,the drag torque,stroke deviation,acceleration peak value,axial contact stiffness and other parameters of the BSM under different speeds are ob-tained,and the different preloads are obtained by the drag torque,the changing regularity of which is consistent with the simulation results.A comprehensive analysis of the experimental data reveals that the dynamic characteristics of the ball screw’s spatial motion are significantly influenced by gy-roscopic torque effects.By incorporating these parametric effects,the accuracy degradation charac-teristics of ball screw under different preloads and speeds can be well analyzed.This methodology establishes a technical foundation for investigating ball screw accuracy retention characteristics.
基金supported by the National Key R&D Program of China(Grant No.2017YFC0805309)Natural Science Foundation of Fujian Province(Grant No.2021J01820)Department of Education of Fujian Province Project(Grant Nos.JAT190294 and JAT210230).
文摘Considering the uncertainty of the speed of horizontal transportation equipment,a cooperative scheduling model of multiple equipment resources in the automated container terminal was constructed to minimize the completion time,thus improving the loading and unloading efficiencies of automated container terminals.The proposed model integrated the two loading and unloading processes of“double-trolley quay crane+AGV+ARMG”and“single-trolley quay crane+container truck+ARMG”and then designed the simulated annealing particle swarm algorithm to solve the model.By comparing the results of the particle swarm algorithm and genetic algorithm,the algorithm designed in this paper could effectively improve the global and local space search capability of finding the optimal solution.Furthermore,the results showed that the proposed method of collaborative scheduling of multiple equipment resources in automated terminals considering hybrid processes effectively improved the loading and unloading efficiencies of automated container terminals.The findings of this study provide a reference for the improvement of loading and unloading processes as well as coordinated scheduling in automated terminals.
基金the Shanghai Pujiang Program (No.22PJD030),the National Natural Science Foundation of China (Nos.61603244 and 71904116)the National Natural Science Foundation of China-Shandong Joint Fund (No.U2006228)。
文摘The overall performance of multi-robot collaborative systems is significantly affected by the multi-robot task allocation.To improve the effectiveness,robustness,and safety of multi-robot collaborative systems,a multimodal multi-objective evolutionary algorithm based on deep reinforcement learning is proposed in this paper.The improved multimodal multi-objective evolutionary algorithm is used to solve multi-robot task allo-cation problems.Moreover,a deep reinforcement learning strategy is used in the last generation to provide a high-quality path for each assigned robot via an end-to-end manner.Comparisons with three popular multimodal multi-objective evolutionary algorithms on three different scenarios of multi-robot task allocation problems are carried out to verify the performance of the proposed algorithm.The experimental test results show that the proposed algorithm can generate sufficient equivalent schemes to improve the availability and robustness of multi-robot collaborative systems in uncertain environments,and also produce the best scheme to improve the overall task execution efficiency of multi-robot collaborative systems.
文摘With the rapid development of modern agriculture,the prevention and control of crop diseases and insect pests has become an important part to ensure the safety of agricultural production,the quality of agricultural products and the safety of agricultural ecological environment.Although the effect of traditional chemical prevention and control technology is remarkable,the health risks and environmental problems brought by it should not be ignored.As a green and environmentally friendly means of prevention and control,biological prevention and control technology has gradually become a hot research topic and a trend of agricultural production.This paper is intended to comprehensively evaluate the social costs of biological control technologies for crop diseases and pests,including the health risks reduced,environmental improvements,economic benefits,and barriers to promotion,and put forward corresponding policy recommendations.
文摘In the field of biological control of agricultural and forestry pests,natural enemy insects play an important role,constituting the core of modern integrated pest management(IPM)strategy,providing solid support for the zero growth goal of chemical pesticide use,and helping the sustainable development of green agriculture.The rise of the natural enemy insect industry has become a key driver of the transformation of green agriculture,injecting vitality into the sustainability and ecological protection of agriculture.With the increasing concern about food safety,environmental protection and ecological balance all over the world,the application scope of natural enemy insects as biological control means is constantly expanding.Its unique ecological adaptability and environmentally friendly characteristics help to reduce dependence on chemical pesticides,ensure the safety of agricultural products and maintain ecological diversity.The purpose of this study is to analyze the current situation of natural enemy insect industry,evaluate its cost and benefit,emphasize its great significance in promoting the transformation of green agriculture,improving production efficiency and promoting ecological protection by drawing lessons from foreign successful experiences,and explore an efficient and sustainable new agricultural development model.
基金This work was partially supported by the Shandong Joint Fund of the National Nature Science Foundation of China(U2006228)the National Nature Science Foundation of China(61603244).
文摘Maintaining population diversity is an important task in the multimodal multi-objective optimization.Although the zoning search(ZS)can improve the diversity in the decision space,assigning the same computational costs to each search subspace may be wasteful when computational resources are limited,especially on imbalanced problems.To alleviate the above-mentioned issue,a zoning search with adaptive resource allocating(ZS-ARA)method is proposed in the current study.In the proposed ZS-ARA,the entire search space is divided into many subspaces to preserve the diversity in the decision space and to reduce the problem complexity.Moreover,the computational resources can be automatically allocated among all the subspaces.The ZS-ARA is compared with seven algorithms on two different types of multimodal multi-objective problems(MMOPs),namely,balanced and imbalanced MMOPs.The results indicate that,similarly to the ZS,the ZS-ARA achieves high performance with the balanced MMOPs.Also,it can greatly assist a“regular”algorithm in improving its performance on the imbalanced MMOPs,and is capable of allocating the limited computational resources dynamically.
基金supported by the Strategic Research Grants from City University of Hong Kong [Project No. CityU-SRG 7002370]the National Natural Science Foundation of China (Grant No. 10972135)+1 种基金Science Foundation of Shanghai Maritime University(Grant No. 20110046)the Science Foundation of Shanghai Science Commission (Grant Nos. 09DZ2250400 and 09530708200)
文摘This paper proposes an improved cellular automaton model to describe the urban traffic flow with the consideration of traffic light and driving behaviour effects. Based on the model, the characteristics of the urban traffic flow on a single- lane road are investigated under three different control strategies, i.e., the synchronized, the green wave and the random strategies. The fundamental diagrams and time-space patterns of the traffic flows are provided for these strategies respectively. It finds that the dynamical transition to the congested flow appears when the vehicle density is higher than a critical level. The saturated flow is less dependent on the cycle time and the strategies of the traffic light control, while the critical vehicle density varies with the cycle time and the strategies. Simulated results indicate that the green wave strategy is proven to be the most effective one among the above three control strategies.
基金supported by the National Natural Science Foundation of China(31772027)the Key Project in Applied Technology of Chongqing Science and Technology Bureau,China(cstc2017shms-xdny80058)。
文摘As a synthetic functional analog of salicylic acid, 2,6-dichloroisonicotinic acid(INA) is effective in inducing the host disease resistance of a plant against a pathogen. The effects of INA on controlling postharvest blue and green molds and anthracnose decay and defense-related enzymes on citrus fruits were investigated, and the ascorbic acid of naturally infected citrus flavedo was also measured. Results showed that 1.0 mmol L^(–1) INA treatments significantly reduced blue and green molds and anthracnose decay development on both wound-inoculated fruit and naturally-infected fruit compared with the control fruit. The treatment effectively enhanced the β-1,3-glucanase(GLU), chitinase(CHI), phenylalanine ammonia-lyase(PAL) and peroxidase(POD) activities and the polyphenol oxidase(PPO) in flavedo. The results presented here suggest that INA might be used as a chemical fungicide substitution to control postharvest diseases in citrus fruits.
基金the Innovation Action Project from Science and Technology Commission of Shanghai Municipality (No. 08170511300)
文摘The throughput capacity of a container terminal is very important in planning and designing at container terminals.The existing methods estimated the throughput capacity without considering its change resulting from the different combination patterns of the types of arriving vessels.A simulation model is established to estimate the throughput capacities of a container terminal under different combination patterns of the types of arriving vessels.It shows that the throughput capacity of a container terminal is influenced by the utilization rates of the berth and quay cranes which result from the different combination patterns of the types of the arriving vessels.It provides a practical approach to estimate the throughput capacity of a container terminal considering the types of the vessels,and it is also helpful for the decision makers to raise the throughputs of the container terminals by optimizing the combination patterns of the types of arriving vessels.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11262003 and 11302125)the Fund from the Shanghai Science and Technology Commission,China(Grant No.12PJ1404000)the Graduate Student Innovative Foundation of Guangxi Zhuang Autonomous Region,China(Grant No.YCSZ2012013)
文摘In this paper, a cellular automaton model considering game strategy update is proposed to study the pedestrian evac- uation in a hall. Pedestrians are classified into two categories, i.e., cooperators and defectors, and they walk to an exit according to their own strategy change. The conflicts that two or three pedestrians try to occupy the same site at the same time are investigated in the Game theory model. Based on it, the relationship between the pedestrian flow rate and the evacuation time as well as the variation of cooperative proportion against evacuation time is investigated from the different initial cooperative proportions under the influence of noise. The critical value of the noise is found when there is a small number of defectors in the initial time. Moreover, the influences of the initial cooperative proportion and strength of noise on evacuation are discussed. The results show that the lower the initial cooperative proportion as well as the bigger the strength of noise, the longer the time it takes for evacuation.
基金Supported by the Research Grants from Shanghai Municipal Natural Science Foundation（No.10190502500） Shanghai Maritime University Start-up Funds,Shanghai Science＆Technology Commission Projects（No.09DZ2250400） Shanghai Education Commission Project（No.J50604）
文摘Secure storage yard is one of the optimal core goals of container transportation;thus,making the necessary storage arrangements has become the most crucial part of the container terminal management systems（CTMS）.This paper investigates a random hybrid stacking algorithm（RHSA） for outbound containers that randomly enter the yard.In the first stage of RHSA,the distribution among blocks was analyzed with respect to the utilization ratio.In the second stage,the optimization of bay configuration was carried out by using the hybrid genetic algorithm.Moreover,an experiment was performed to test the RHSA.The results show that the explored algorithm is useful to increase the efficiency.
文摘The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection function,which enables multiplex PCR reaction.In this study,this technique was used to establish triple dPCR detection for the genetically modified soybean MON87708 × MON89788 with stacked traits.Specific absolute quantitative detection was accomplished for the genomic DNA extracted from the homogenized seeds of GM stack MON87708× MON89788 soybean.Our results can serve as a reference for the absolute quantitative detection of stacked events of genetically modified crops.
文摘As online trade and interactions on the internet are on the rise, a key issue is how to use simple and effective evaluation methods to accomplish trust decision-making for customers. It is well known that subjective trust holds uncertainty like randomness and fuzziness. However, existing approaches which are commonly based on probability or fuzzy set theory can not attach enough importance to uncertainty. To remedy this problem, a new quantifiable subjective trust evaluation approach is proposed based on the cloud model. Subjective trust is modeled with cloud model in the evaluation approach, and expected value and hyper-entropy of the subjective cloud is used to evaluate the reputation of trust objects. Our experimental data shows that the method can effectively support subjective trust decisions and provide a helpful exploitation for subjective trust evaluation.
基金supported by the National Key R&D Program of China(2019YFD1002300).
文摘Jujube fruits usually suffer from physiological disorders or infectious diseases during storage,leading to quality deterioration,softening,or rotting.Therefore,this study aims to investigate the effect of methionine soaking treatment on the postharvest jujube fruit decay rate and storage quality.Methionine treatment significantly reduced the decay rate of postharvest jujube fruit and effectively maintained fruit color and titratable acid.Methionine treatment effectively delayed the decrease of firmness,soluble solids,ascorbic acid,and lignin contents in jujube fruit.Methionine treatment reduced the content of alanine and phenylalanine,and increased the content of glycine in jujube fruit,but displayed no significant effect on total amino acid content.In addition,jujube fruits in the methionine treatment group had a higher total phenolic and flavonoid content and antioxidant capacity,both in free and bound forms.Compared with the control,methionine treatment also significantly increased the content of individual phenolic acid fractions(gallic acid,vanillic acid,and syringic acid)and flavonoid fractions(catechin,epicatechin,rutin)in free form as well as individual phenolic acid fractions in bound form(gallic acid and ferulic acid)in jujube fruits.Overall,this study suggested that the methionine treatment could be used as a prospective preservative to reduce the postharvest decay of jujube fruit and alleviate its nutritional quality deterioration during cold storage at 4°C.
文摘Expert system plays an important role in port machine diagnosis, which aims at automatic equipment test for higher availability and efficiency of port operations. In this study, a port machine diagnosis expert system is proposed based on multi-reasoning mechanism. Relying on the knowledge acquired from the experienced experts in the port machine engineering, the system builds a library of relative experience and a set of rules of reasoning and estimating. Multi-reasoning mechanism that simulates the decision-making process of domain experts is employed to achieve reliable diagnosis results. The reasoning machine integrates artificial neural network, uncertain decision making and decision tree, which complements each other by sustainable growing voting mechanism. The effect of this multi-reasoning mechanism is evaluated and validated by means of Matthew＇s Correlation Coefficient （MCC）. The system incorporating the mechanism is successfully designed, implemented and applied in Shanghai Port.
基金This research was supported by a grant from R&D Program of the Korea Railroad Research Institute,Republic of Korea.
文摘This paper is on the suggestion of maintenance items for electric railway facility systems.With the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility systems are also increasing,but the railroad electrical facility system in Korea is rapidly aging.To solve this problem,various methodologies are applied to ensure operational reliability and stability for railroad electrical facility systems,but there is a lack of detailed evaluation criteria for railroad electrical facility system maintenance.Also,maintenance items must be selected in a scientific and systematic method.Therefore,railroad electrical facility systems are selected for study.Design StructureMatrix(DSM)is utilized to establish considerations tailored to the maintenance characteristics,and the Fuzzy-TOPSIS methodology is utilized for determining the maintenance detail evaluation item baseline weights,a multi-criteria decision-making problem.Studies show that degradation,insulation items have the highest weight of 14.63%,and capacity items have the lowest weight of 5.34%.The results of this may be contributed to the underlying research in carrying out maintenance activities to ensure the reliability and safety of railroad electrical facility systems.
基金supported by the Guizhou Provincial Science and Technology Projects,China(ZK[2022]391)the Cultivation Project of National Natural Science Foundation of Guizhou Medical University,China(21NSFCP20).
文摘Jincheng orange(Citrus sinensis Osbeck)is widely grown in Chongqing,China,and is commonly consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds.The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time.However,the influence of growth stages on the volatile compounds in Jincheng orange remains unclear.In addition,volatiles originate from fatty acids,most of which are the precursors of volatile substances.On this basis,gas chromatography-mass spectrometry(GC-MS)was performed to elaborate the changes in volatile constituents and fatty acids as precursors.This study tested proximately 60 volatiles and 8 fatty acids at 9 growth and development stages(AF1-AF9).Of those compounds,more than 92.00%of total volatiles and 87.50%of fatty acids were terpenoid and saturated fatty acids,respectively.As shown in the PCA plot,the AF5,AF6,and AF9 stages were confirmed as completely segregated and appeared different.In addition,most of the volatiles and fatty acids first increased at the beginning of the development stage,then decreased from the AF6 development stage,and finally increased at the AF9 maturity stage.Moreover,the highest contents of terpenoid,alcohols,aldehydes,ketones,and saturated fatty acids in Jincheng orange peel oil were d-limonene,linalool,octanal,cyclohexanone,and stearic acid during development stages,respectively.Our results found that the growth stages significantly affected the volatile constituents and precursors in Jincheng orange peel oil.
基金supported by National Natural Science Foundation of China(Nos.61603244 and 41505001)Fundamental Research Funds for the Central Universities(No.222201717006)
文摘The search efficiency of differential evolution （DE） algorithm is greatly impacted by its control parameters. Although many adaptation/self-adaptation techniques can automatically find suitable control parameters for the DE, most techniques are based on pop- ulation information which may be misleading in solving complex optimization problems. Therefore, a self-adaptive DE （i.e., JADE） using two-phase parameter control scheme （TPC-JADE） is proposed to enhance the performance of DE in the current study. In the TPC-JADE, an adaptation technique is utilized to generate the control parameters in the early population evolution, and a well-known empirical guideline is used to update the control parameters in the later evolution stages. The TPC-JADE is compared with four state-of-the-art DE variants on two famous test suites （i.e., IEEE CEC2005 and IEEE CEC2015）. Results indicate that the overall performance of the TPC-JADE is better than that of the other compared algorithms. In addition, the proposed algorithm is utilized to obtain optimal nutrient and inducer feeding for the Lee-Ramirez bioreactor. Experimental results show that the TPC-JADE can perform well on an actual dynamic optimization problem.
文摘A dynamic pricing model was established based on forecasting the demand for container handling of a specific shipping company to maximize terminal profits to solve terminal handling charges under the changing market environment.It assumes that container handling demand depends on the price and the unknown parameters in the demand model.The maximum quasi-likelihood estimation(MQLE)method is used to estimate the unknown parameters.Then an adaptive dynamic pricing policy algorithm is proposed.At the beginning of each period,through dynamic pricing,determining the optimal price relative to the estimation value of the current parameter and attach a constraint of differential price decision.Meanwhile,the accuracy of demand estimation and the optimality of price decisions are balanced.Finally,a case study is given based on the real data of Shanghai port.The results show that this pricing policy can make the handling price converge to the stable price and significantly increase this shipping company’s handling profit compared with the original“contractual pricing”mechanism.
基金Supported by Research Grants from City University of Hong Kong,HKSAR under Grant No.CityU-SRG 7002684Science&Technology Program of Shanghai Maritime University under Grant No.20110046+1 种基金Shanghai Municipal Natural Science Foundation under Grant No.10190502500National Natural Science Foundation of China under Grant Nos.11172164,71101088 and 71171129
文摘This paper reports a study concerning occurrence and growth of traffic jam in a harbor tunnel. The single-lane with three sections （downgrade, fiat, and upgrade） is taken into account and they are characterized with different velocity limit. At the low density, the traffic current increases linearly with density and saturates at some values of immediately density. As the density increases, the traffic jam appears firstly before the upgrade section and then extends to the downgrade section. Additionally, the relationships of the velocity and headway against position in different densities are obta/ned from simulation. These results clearly clarify where and when the traffic jam appears. Finally, the critical densities are derived via the theoretical analysis before and after the discontinuous fronts and the theoretical results are consistent with the critical values of simulation results.
