基于信息一体化VMI模式的军事物流配送研究

文章首先介绍了一种新的库存管理方法—供应商管理用户库存（Vendor Managed Inventory）,并分析了目前我军的装备物资配送现状;然后在此基础上提出了基于信息一体化的军事配送中心管理库存模式,将其划分为需求预测模块和配送计划模块,并规划了系统的工作流程;最后介绍了该系统的三种技术支持。     

陕西秦巴山区产时保健质量与儿童智能发育相关因素分析

为探讨产时保健质量与儿童智能发育的相关因素,采用病例一对照研究,对秦巴山区弱智儿童（ＭＲ组）１１０名和智力正常儿童（对照组）１２６名的母亲产时情况进行了单因素分析。结果发现：ＭＲ组的胎儿宫内窘迫、新生儿重度窒息、早产、低体重儿、无产前检查、旧法接生率（分别为１４．５５％、８．１８％、１０．００％、３０．００％、５３．６４％、５４．５５％）均高于对照组（分别为３．９７％、２．３０％、２．３０％、１３．４９％、３７,３０％、３２．５４％）,差异有显著性（Ｐ＜０．０５）;而ＭＲ组新生儿轻、中度室息、滞产的发生率（分别为２１,８２％、１２．７３％）与对照组（分别为１３．９４％、９．５２％）无显著性差异（Ｐ＞０．０５）。提示胎儿宫内窘迫、新生儿重度窒息、早产、低体重儿、无产前检查、旧法接生均与儿童智能发育有显著相关性,新生儿轻、中度窒息、滞产与儿童智能发育无显著相关性。     

高速铁路开展快运物流有关问题的探讨

我国拥有世界上规模最大、速度最快、管理经验最丰富的高速铁路网,为开展高速铁路快运物流打下了坚实的基础,但目前高速铁路快运物流的占比却并不理想.针对此问题,本文就现代化物流条件下,高速铁路如何更好地开展快运物流进行了研究,分析了目前我国高速铁路快运存在的主要问题,提出了高速铁路办理快运物流的潜在运量,并对高速铁路快运的运...     

Quantifying environmental and financial benefits of using porters and cycle couriers for last-mile parcel delivery

Parcel carriers face increasingly difficult operating conditions in busy metropolitan areas due to growing consumer demand for ever faster delivery services and having to cope with traffic congestion and city authority measures that may restrict or penalise access for certain types of vehicle. This paper evaluates the potential environmental and financial benefits of switching from traditional van-based deliveries to an alternative operating model, where porters or cycle couriers undertake deliveries supported by a substantially reduced van fleet.Results using a specially-developed algorithm to model operations of a real carrier in an area of central London, UK, suggested that the carrier could reduce CO₂ emissions by 45%, NOx emissions by 33%, driving distance by 78% and curbside parking time by 45%. Overall cost savings to the carrier were estimated to be in the range 34–39%. Scaling up the modelled emissions savings to London’s Central Activities Zone, an area of approximately 30 km² and with current total annual parcel delivery distance of around 15 million km, could see annual emissions savings in the region of 2 million kg CO₂ and 1633 kg NOx if all carriers utilised porters or cycle couriers. The key operating challenges identified were related to sorting and consolidating items by weight and volume, parcel handover arrangements and how to deal with express items and failed deliveries.     

基于客户分类的即时配送路径优化研究

大数据背景下即时配送平台对客户进行精细化管理已成为可能.为寻求企业长期发展，将客户分类融入到车辆路径问题中，用有限的资源提高配送准时性以得到优质客户的维持和发展，为企业赢得更多潜在效益.本文结合客户的消费行为将客户分为多个层级，根据每层级客户的特点设置超时惩罚成本，构建出基于客户分类的即时配送路径优化模型，并根据问题特点设计遗传算法求解，最后，结合某即时配送平台的业务场景进行案例分析，验证了模型和算法的有效性.     

Evaluating CO2 emissions, cost, and service quality trade-offs in an urban delivery system case study

Growing pressure to limit greenhouse gas emissions is changing the way businesses operate. This paper presents the trade-offs between cost, service quality (represented by time window guarantees), and emissions of an urban pickup and delivery system under these changing pressures. A model, developed by the authors in ArcGIS, is used to evaluate these trade-offs for a specific case study involving a real fleet with specific operational characteristics. The problem is modeled as an emissions minimization vehicle routing problem with time windows. Analyses of different external policies and internal operational changes provide insight into the impact of these changes on cost, service quality, and emissions. Specific consideration of the influence of time windows, customer density, and vehicle choice are included.The results show a stable relationship between monetary cost and kilograms of CO₂, with each kilogram of CO₂ associated with a $3.50 increase in cost, illustrating the influence of fuel use on both cost and emissions. In addition, customer density and time window length are strongly correlated with monetary cost and kilograms of CO₂ per order. The addition of 80 customers or extending the time window 100 minutes would save approximately $3.50 and 1 kilogram of CO₂ per order. Lastly, the evaluation of four different fleets illustrates significant environmental and monetary gains can be achieved through the use of hybrid vehicles.The results demonstrate there is not a trade-off between CO₂ emissions and cost, but that these two metrics trend together. This suggests the most effective way to encourage fleet operators to limit emissions is to increase the cost of fuel or CO₂ production, as this is consistent with current incentives that exist to reduce cost, and therefore emissions.     

Designing optimal autonomous vehicle sharing and reservation systems: A linear programming approach

Autonomous vehicle (AV) technology holds great promise for improving the efficiency of traditional vehicle sharing systems. In this paper, we investigate a new vehicle sharing system using AVs, referred to as autonomous vehicle sharing and reservation (AVSR). In such a system, travelers can request AV trips ahead of time and the AVSR system operator will optimally arrange AV pickup and delivery schedules and AV trip chains based on these requests. A linear programming model is proposed to efficiently solve for optimal solutions for AV trip chains and required fleet size through constructed AVSR networks. Case studies show that AVSR can significantly increase vehicle use rate (VUR) and consequentially reduce vehicle ownership significantly. In the meantime, it is found that the actual vehicle miles traveled (VMT) in AVSR systems is not significantly more than that of conventional taxis, despite inevitable empty hauls for vehicle relocation in AVSR systems. The results imply huge potential benefits from AVSR systems on improving mobility and sustainability of our current transportation systems.     

Understanding the impact of e-commerce on last-mile light goods vehicle activity in urban areas: The case of London

Growth in e-commerce has led to increasing use of light goods vehicles for parcel deliveries in urban areas. This paper provides an insight into the reasons behind this growth and the resulting effort required to meet the exacting delivery services offered by e-retailers which often lead to poor vehicle utilisation in the last-mile operation, as well as the duplication of delivery services in urban centres as competitors vie for business. A case study investigating current parcel delivery operations in central London identified the scale of the challenge facing the last-mile parcel delivery driver, highlighting the importance of walking which can account for 62% of the total vehicle round time and 40% of the total round distance in the operations studied. The characteristics of these operations are in direct conflict with the urban infrastructure which is being increasingly redesigned in favour of walking, cycling and public transport, reducing the kerbside accessibility for last-mile operations. The paper highlights other pressures on last-mile operators associated with managing seasonal peaks in demand; reduced lead times between customers placing orders and deliveries being made; meeting delivery time windows; first-time delivery failure rates and the need to manage high levels of product returns. It concludes by describing a range of initiatives that retailers and parcel carriers, sometimes in conjunction with city authorities, can implement to reduce the costs associated with last-mile delivery, without negatively impacting on customer service levels.     

A decomposition-based iterative optimization algorithm for traveling salesman problem with drone

This study investigates a new delivery problem that has emerged after the attempts of several e-commerce and logistics firms to deploy drones in their operations to increase efficiency and reduce delivery times. In this problem, a delivery truck that carries a drone on its roof serves customers in coordination with a drone. The drone is considered to complement the truck due to its cost-efficiency and ability to access difficult terrains and to travel without exposure to congestion. This study presents an iterative algorithm that is based on a decomposition approach to minimize delivery completion time. In the first stage of the proposed methodology, the truck route and the customers assigned to the drone are determined. In the second stage, a mixed-integer linear programming model is solved to optimize the drone route by fixing the routing and the assignment decisions that are made in the first stage. Beginning with the shortest truck route, the assignment and the routing decisions are iteratively improved. The solution times of our algorithm are compared with the solution times of the state-of-the-art formulations that are solved by CPLEX. The results demonstrate that our algorithm yields shorter solution times for the instances that we generated with the specified parameters. An optimization-based heuristic algorithm, which obtains solutions for medium-sized instances, is developed by reducing the feasible search area.     

Combining pickups and deliveries in vehicle routing – An assessment of carbon emission effects

This paper studies the effect on carbon emissions of consolidation of shipments on trucks. New positioning and communication technologies, as well as decision support systems for vehicle routing, enable better utilization of vehicle capacity, reduced travel distance, and thereby carbon emission reductions. We present a novel carbon emission analysis method that determines the emission savings obtained by an individual transport provider, who receives customer orders for outbound deliveries as well as pickup orders from supply locations. The transport provider can improve vehicle utilization by performing pickups and deliveries jointly instead of using separate trucks. In our model we assume that the transport provider minimizes costs by use of a tool that calculates detailed vehicle routing plans, i.e., an assignment of each transport order to a specific vehicle in the fleet, and the sequence of customer visit for each vehicle. We compare a basic set-up, in which pickups and deliveries are segregated and performed with separate vehicles, with two consolidation set-ups where pickups and deliveries may be mixed more or less freely on a single vehicle. By allowing mixing, the average vehicle load will increase and the total driven distance will decrease. To compare carbon emissions for the three set-ups, we use a carbon assessment method that uses the distance driven and the average load factor. An increase in the load factor can reduce part of the emission savings from consolidation. We find that emission savings are relatively large in case of small vehicles and for delivery and pickup locations that are relatively far from the depot. However, if a truck visits many demand and supply locations before returning to the depot, we observe negligible carbon emission decreases or even emission increases for consolidation set-ups, meaning that in such cases investing in consolidation through joint pickups and deliveries may not be effective. The results of our study will be useful for transport users and providers, policymakers, as well as vehicle routing technology vendors.