In this study,we introduce an integrated schedule of order picking and delivery for instant delivery.Order picking,including order batching and picking sequencing,is scheduled online under real-time order arrival,whic...In this study,we introduce an integrated schedule of order picking and delivery for instant delivery.Order picking,including order batching and picking sequencing,is scheduled online under real-time order arrival,which integrates order delivery by depicting order location dispersion in an online order picking strategy.Order delivery,including delivery person assignment and route planning,is modeled to minimize the total duration of order fulfillment by considering the influence of the order picking completion time.A rule-based online order picking strategy is established,and a customized ant colony optimization(ACO)algorithm is proposed to optimize order delivery.Experiments on 16 simulated instances of different scales demonstrate that our online order picking schedule considering order delivery outperforms existing approaches and that the customized ACO algorithm for order delivery is effective.展开更多
The rise in online home delivery services(OHDS)has had a significant impact on how urban services are supplied and used in recent years.Studies on the spatial accessibility of OHDS are emerging,but few is known about ...The rise in online home delivery services(OHDS)has had a significant impact on how urban services are supplied and used in recent years.Studies on the spatial accessibility of OHDS are emerging,but few is known about the temporal dimension of OHDS accessibility as well as the geographic and socioeconomic differences in the spatiotemporal accessibility of OHDS.This study measures the spatiotemporal accessibility of four types of OHDS,namely leisure,fresh and convenient,medical,and catering services.The geographic and socioeconomic disparities in the spatiotemporal accessibility of these four types of OHDS are then identified using spatial statistical methods and the Kruskal-Wallis test(K-W test).The case study in Nanjing,China,suggests that:1)spatiotemporal accessibility better reflects the temporal variation of OHDS accessibility and avoids overestimation of OHDS accessibility when only considering its spatial dimension.2)The spatiotemporal accessibility of OHDS varies geographically and socioeconomically.Neighborhoods located in the main city or neighborhoods with higher housing prices,higher population density,and higher point of interest(POI)mix have better OHDS spatiotemporal accessibility.Our study contributes to the understanding of OHDS accessibility from a spatiotemporal perspective,and the empirical insights can assist policymakers in creating intervention plans that take into account variations in OHDS spatiotemporal accessibility.展开更多
Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliv...Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliveries. Careful design of the meal preparation and order delivery systems is needed to avoid excessive cust omer waiting time bet ween ordering and delivery. This paper considers the meal preparation and delivery processes simultaneously to approximate average customer waiting time for deliveries. The authors first discuss the system performance with one cook and unit-capacity delivery vehicles, using an M/G/1queue and a GI/G/1queue. Numerical experiments show that our approximation can adequately describe real waiting times. Then, series queues with multiple cooks and multi-capacity delivery vehicles, e.g., an M/G/n queue and a GI/Gn/1 queue, are examined. Results show that except for situations with a large meal preparation time and a small vehicle capacity, compared with the result of simulation, the approximation in this paper is acceptable with a deviation of less than 20%. The marginal decrease in waiting time associated with hiring more vehicles is est.imated under different meal preparation speeds, sizes of service area and vehicle capacities.展开更多
<div style="text-align:justify;"> <span style="font-family:Verdana;">Average Bangladeshis spend a significant amount of income on medicine. A reliable and fast online medicine delivery ...<div style="text-align:justify;"> <span style="font-family:Verdana;">Average Bangladeshis spend a significant amount of income on medicine. A reliable and fast online medicine delivery system is not ubiquitous. Most people buy medicine from the local Pharmacies. They need to go to medicine stores to buy the specific medicine prescribed by the specialized doctors. Sometimes all prescribed medicines are not available in local Pharmacies therefore people need to go to other areas to buy the medicines. It is very time consuming and people need to spend money as well for this. In our country, traffic jams are a very big problem. People waste longer time on the road due to traffic jams. Here most of the pharmacies are closed at night time but sometimes in an emergency situation medicine is very essential. In this case an online web based e-commerce medicine delivery system is needed very much. In addition, currently the whole world is suffering due to COVID-19 pandemic. Coronavirus is very contagious which we all know. In this pandemic time it is not risk free to go out to buy medicine from the pharmacies. Due to COVID-19, medicine scarcity is also an important issue. In this situation, an online medicine delivery system can play an important role. By considering the above mentioned facts, a reliable and fast online solution is proposed. This paper presents the development of a web based online medicine delivery system. A reliable, fast, safe and user-friendly online based e-commerce web application has been developed in this paper. Medicine delivery system has also been included with this proposed system. This platform is a dynamic web application built in Hypertext Preprocessor (PHP) based Laravel framework with a powerful back end. It is hosted on a dedicated Virtual Private Server (VPS). This system is lightning fast and optimized very well for searching engines. With the help of the developed platform, drugs will be available at one’s doorstep very fast, safely and reliably. In this system, users can choose a me展开更多
Cationic polymers have been receiving much attention as non-viral gene vectors. The aqueous mobile phase was optimized in combination with Shodex OHpak SB columns for size-exclusion chromatography （SEC） analysis of ...Cationic polymers have been receiving much attention as non-viral gene vectors. The aqueous mobile phase was optimized in combination with Shodex OHpak SB columns for size-exclusion chromatography （SEC） analysis of disulfide-containing poly（ethylene imine） （PEI） derivatives used in gene delivery. Addition of acetonitrile in mobile phase was shown to be able to suppress the hydrophobic interactions between polymer analytes and the stationary phase. The absolute molecular weights and distributions of the cationic polymers were determined directly from online SEC-MALS （multi-angle light scattering）/RI （refractive index detector）. The results demonstrate that a good SEC separation of disulfide-containing PEI derivatives used in gene delivery with little band broadening was achieved.展开更多
基金supported by the National Natural Science Foundation of China(72032001,71972071)the Ministry of Education,Humanities and Social Sciences Research Planning Foundation(21YJA630057).
文摘In this study,we introduce an integrated schedule of order picking and delivery for instant delivery.Order picking,including order batching and picking sequencing,is scheduled online under real-time order arrival,which integrates order delivery by depicting order location dispersion in an online order picking strategy.Order delivery,including delivery person assignment and route planning,is modeled to minimize the total duration of order fulfillment by considering the influence of the order picking completion time.A rule-based online order picking strategy is established,and a customized ant colony optimization(ACO)algorithm is proposed to optimize order delivery.Experiments on 16 simulated instances of different scales demonstrate that our online order picking schedule considering order delivery outperforms existing approaches and that the customized ACO algorithm for order delivery is effective.
基金Under the auspices of National Natural Science Foundation of China (No.42330510)。
文摘The rise in online home delivery services(OHDS)has had a significant impact on how urban services are supplied and used in recent years.Studies on the spatial accessibility of OHDS are emerging,but few is known about the temporal dimension of OHDS accessibility as well as the geographic and socioeconomic differences in the spatiotemporal accessibility of OHDS.This study measures the spatiotemporal accessibility of four types of OHDS,namely leisure,fresh and convenient,medical,and catering services.The geographic and socioeconomic disparities in the spatiotemporal accessibility of these four types of OHDS are then identified using spatial statistical methods and the Kruskal-Wallis test(K-W test).The case study in Nanjing,China,suggests that:1)spatiotemporal accessibility better reflects the temporal variation of OHDS accessibility and avoids overestimation of OHDS accessibility when only considering its spatial dimension.2)The spatiotemporal accessibility of OHDS varies geographically and socioeconomically.Neighborhoods located in the main city or neighborhoods with higher housing prices,higher population density,and higher point of interest(POI)mix have better OHDS spatiotemporal accessibility.Our study contributes to the understanding of OHDS accessibility from a spatiotemporal perspective,and the empirical insights can assist policymakers in creating intervention plans that take into account variations in OHDS spatiotemporal accessibility.
基金supported by the National Natural Science Foundation of China under Grant No.71661167009the Fundamental Research Funds for the Central Universities under Grant No.B17JB00280
文摘Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliveries. Careful design of the meal preparation and order delivery systems is needed to avoid excessive cust omer waiting time bet ween ordering and delivery. This paper considers the meal preparation and delivery processes simultaneously to approximate average customer waiting time for deliveries. The authors first discuss the system performance with one cook and unit-capacity delivery vehicles, using an M/G/1queue and a GI/G/1queue. Numerical experiments show that our approximation can adequately describe real waiting times. Then, series queues with multiple cooks and multi-capacity delivery vehicles, e.g., an M/G/n queue and a GI/Gn/1 queue, are examined. Results show that except for situations with a large meal preparation time and a small vehicle capacity, compared with the result of simulation, the approximation in this paper is acceptable with a deviation of less than 20%. The marginal decrease in waiting time associated with hiring more vehicles is est.imated under different meal preparation speeds, sizes of service area and vehicle capacities.
文摘<div style="text-align:justify;"> <span style="font-family:Verdana;">Average Bangladeshis spend a significant amount of income on medicine. A reliable and fast online medicine delivery system is not ubiquitous. Most people buy medicine from the local Pharmacies. They need to go to medicine stores to buy the specific medicine prescribed by the specialized doctors. Sometimes all prescribed medicines are not available in local Pharmacies therefore people need to go to other areas to buy the medicines. It is very time consuming and people need to spend money as well for this. In our country, traffic jams are a very big problem. People waste longer time on the road due to traffic jams. Here most of the pharmacies are closed at night time but sometimes in an emergency situation medicine is very essential. In this case an online web based e-commerce medicine delivery system is needed very much. In addition, currently the whole world is suffering due to COVID-19 pandemic. Coronavirus is very contagious which we all know. In this pandemic time it is not risk free to go out to buy medicine from the pharmacies. Due to COVID-19, medicine scarcity is also an important issue. In this situation, an online medicine delivery system can play an important role. By considering the above mentioned facts, a reliable and fast online solution is proposed. This paper presents the development of a web based online medicine delivery system. A reliable, fast, safe and user-friendly online based e-commerce web application has been developed in this paper. Medicine delivery system has also been included with this proposed system. This platform is a dynamic web application built in Hypertext Preprocessor (PHP) based Laravel framework with a powerful back end. It is hosted on a dedicated Virtual Private Server (VPS). This system is lightning fast and optimized very well for searching engines. With the help of the developed platform, drugs will be available at one’s doorstep very fast, safely and reliably. In this system, users can choose a me
基金supported by the National Natural Science Foundation of China(Nos.20774068,21074100)the Ph.D. Programs Foundation of Ministry of Education of China(No.20070486035)
文摘Cationic polymers have been receiving much attention as non-viral gene vectors. The aqueous mobile phase was optimized in combination with Shodex OHpak SB columns for size-exclusion chromatography （SEC） analysis of disulfide-containing poly（ethylene imine） （PEI） derivatives used in gene delivery. Addition of acetonitrile in mobile phase was shown to be able to suppress the hydrophobic interactions between polymer analytes and the stationary phase. The absolute molecular weights and distributions of the cationic polymers were determined directly from online SEC-MALS （multi-angle light scattering）/RI （refractive index detector）. The results demonstrate that a good SEC separation of disulfide-containing PEI derivatives used in gene delivery with little band broadening was achieved.
