Taking the distribution route optimization of refined oil as background, this paper studies the inventory routing problem of refined oil distribution based on working time equilibrium. In consideration of the constrai...Taking the distribution route optimization of refined oil as background, this paper studies the inventory routing problem of refined oil distribution based on working time equilibrium. In consideration of the constraints of vehicle capacity, time window for unloading oil, service time and demand of each gas station, we take the working time equilibrium of each vehicle as goal and establish an integer programming model for the vehicle routing problem of refined oil distribution, the objective function of the model is to minimize the maximum working time of vehicles. To solve this model, a Lingo program was written and a heuristic algorithm was designed. We further use the random generation method to produce an example with 10 gas stations. The local optimal solution and approximate optimal solution are obtained by using Lingo software and heuristic algorithm respectively. By comparing the approximate optimal solution obtained by heuristic algorithm with the local optimal solution obtained by Lingo software, the feasibility of the model and the effectiveness of the heuristic algorithm are verified. The results of this paper provide a theoretical basis for the scheduling department to formulate the oil distribution plan.展开更多
There is growing interest in the correlation between working time and environmental pressures,but prior empirical studies mostly focused on static methodologies.This article used dynamic panel regression approaches to...There is growing interest in the correlation between working time and environmental pressures,but prior empirical studies mostly focused on static methodologies.This article used dynamic panel regression approaches to examine and compare the relationship among western,southern,and northern European countries over the period 1970-2010,and proved the existence of strongly significant relationships in all models.Furthermore,this article detected the relationship between working hours and environmental indicators(carbon emission and energy use) at different phases.We contribute to a further understanding of the environmental effects of the working time reduction policy by comparing the differences among various periods and country groups in a system generalized method of moments(GMM) dynamic framework.展开更多
China is witnessing a very complicated economic development environment.Migrant workers'working patterns will directly affect their income level and the realization of many economic and social development goals.Th...China is witnessing a very complicated economic development environment.Migrant workers'working patterns will directly affect their income level and the realization of many economic and social development goals.This paper collects relevant data from three places:Shanghai,Lanzhou and Chengdu for empirical research whose results show that determinants of migrant worker's willing working time in urban areas mainly include the“income-consumption difference”,“urban-rural consumption difference”and their“urban income and expenditure uncertainty”.These factors directly affect their effective working time in the city,and determine their choice of choosing corresponding work patterns.From the significant differences of these factors,we can see that migrant workers in China is still struggling to solve their material needs under the pressure of livelihood,and less attention is paid to their spiritual needs and the pursuit of quality of life.展开更多
30 college students who have the habit of lunch time napping (LTN) participated in experiments under two different conditions: Having lunch time napping and not having lunch time napping. They were asked to complete t...30 college students who have the habit of lunch time napping (LTN) participated in experiments under two different conditions: Having lunch time napping and not having lunch time napping. They were asked to complete three tasks in-cluding vigilance reaction, short-term memory, addition arithmetic;their performance was re-corded automatically by computer during 3 dif-ferent periods in the afternoon and early eve-ning. The analysis about the experimental data showed that: as for habitual nappers, midafter-noon nap zone existed, LTN played a very im-portant role in overcoming it, and did great help in enhancing their vigilance in the afternoon and early evening, however, LTN didn’t bring sig-nificant positive effect to executing complex tasks (such as short-term memory and addition task) at the periods of time 16:30-17:30, 20:00- 21:00. Finally, this article discussed the conclu-sions and its significance.展开更多
This paper presents an investigation of temperature, displacement, stress, and induced magnetic field in a half space perfectly-conductive plate. Finite element equations regarding generalized magneto-thermoelasticity...This paper presents an investigation of temperature, displacement, stress, and induced magnetic field in a half space perfectly-conductive plate. Finite element equations regarding generalized magneto-thermoelasticity problems with two relaxation times （i.e., the G-L theory） are derived using the principle of virtual work. For avoiding numerical complication involved in inverse Laplace and Fourier transformation and low precision thereof, the equations are solved directly in time-domain. As a numerical example, the derived equation is used to investigate the generalized magneto-thermoelastic behavior of a semi-infinite plate under magnetic field and subjecting to a thermal shock loading. The results demonstrate that FEM can faithfully predict the deformation of the plate and the induced magnetic field, and most importantly can reveal the sophisticated second sound effect of heat conduction in two-dimensional generalized thermoelastic solids, which is usually difficult to model by routine transformation methods. A peak can be observed in the distribution of stress and induced front and the magnitude of magnetic field at the heat wave the peak decreases with time, which can not be obtained by transformation methods. The new method can also be used to study generalized piezo-thermoelastic problems.展开更多
文摘Taking the distribution route optimization of refined oil as background, this paper studies the inventory routing problem of refined oil distribution based on working time equilibrium. In consideration of the constraints of vehicle capacity, time window for unloading oil, service time and demand of each gas station, we take the working time equilibrium of each vehicle as goal and establish an integer programming model for the vehicle routing problem of refined oil distribution, the objective function of the model is to minimize the maximum working time of vehicles. To solve this model, a Lingo program was written and a heuristic algorithm was designed. We further use the random generation method to produce an example with 10 gas stations. The local optimal solution and approximate optimal solution are obtained by using Lingo software and heuristic algorithm respectively. By comparing the approximate optimal solution obtained by heuristic algorithm with the local optimal solution obtained by Lingo software, the feasibility of the model and the effectiveness of the heuristic algorithm are verified. The results of this paper provide a theoretical basis for the scheduling department to formulate the oil distribution plan.
基金supported by the State Scholarship Fund under the China Scholarship Council[grant number 201306240017]
文摘There is growing interest in the correlation between working time and environmental pressures,but prior empirical studies mostly focused on static methodologies.This article used dynamic panel regression approaches to examine and compare the relationship among western,southern,and northern European countries over the period 1970-2010,and proved the existence of strongly significant relationships in all models.Furthermore,this article detected the relationship between working hours and environmental indicators(carbon emission and energy use) at different phases.We contribute to a further understanding of the environmental effects of the working time reduction policy by comparing the differences among various periods and country groups in a system generalized method of moments(GMM) dynamic framework.
基金The National Social Science Fund of China:Study on the Impact of Migrant Workers'Migrant Birds Work Mode and Employment Security in the Process of Urbanization(15XJL011)。
文摘China is witnessing a very complicated economic development environment.Migrant workers'working patterns will directly affect their income level and the realization of many economic and social development goals.This paper collects relevant data from three places:Shanghai,Lanzhou and Chengdu for empirical research whose results show that determinants of migrant worker's willing working time in urban areas mainly include the“income-consumption difference”,“urban-rural consumption difference”and their“urban income and expenditure uncertainty”.These factors directly affect their effective working time in the city,and determine their choice of choosing corresponding work patterns.From the significant differences of these factors,we can see that migrant workers in China is still struggling to solve their material needs under the pressure of livelihood,and less attention is paid to their spiritual needs and the pursuit of quality of life.
文摘30 college students who have the habit of lunch time napping (LTN) participated in experiments under two different conditions: Having lunch time napping and not having lunch time napping. They were asked to complete three tasks in-cluding vigilance reaction, short-term memory, addition arithmetic;their performance was re-corded automatically by computer during 3 dif-ferent periods in the afternoon and early eve-ning. The analysis about the experimental data showed that: as for habitual nappers, midafter-noon nap zone existed, LTN played a very im-portant role in overcoming it, and did great help in enhancing their vigilance in the afternoon and early evening, however, LTN didn’t bring sig-nificant positive effect to executing complex tasks (such as short-term memory and addition task) at the periods of time 16:30-17:30, 20:00- 21:00. Finally, this article discussed the conclu-sions and its significance.
基金The project supported by the National Natural Science Foundation of China(10132010 and 10472089)
文摘This paper presents an investigation of temperature, displacement, stress, and induced magnetic field in a half space perfectly-conductive plate. Finite element equations regarding generalized magneto-thermoelasticity problems with two relaxation times （i.e., the G-L theory） are derived using the principle of virtual work. For avoiding numerical complication involved in inverse Laplace and Fourier transformation and low precision thereof, the equations are solved directly in time-domain. As a numerical example, the derived equation is used to investigate the generalized magneto-thermoelastic behavior of a semi-infinite plate under magnetic field and subjecting to a thermal shock loading. The results demonstrate that FEM can faithfully predict the deformation of the plate and the induced magnetic field, and most importantly can reveal the sophisticated second sound effect of heat conduction in two-dimensional generalized thermoelastic solids, which is usually difficult to model by routine transformation methods. A peak can be observed in the distribution of stress and induced front and the magnitude of magnetic field at the heat wave the peak decreases with time, which can not be obtained by transformation methods. The new method can also be used to study generalized piezo-thermoelastic problems.
