An Optimization Approach to the Ordering Phase of an Attended Home Delivery Service

Attended Home Delivery (AHD) systems are used whenever a supplying company offers online shopping services that require that customers must be present when their deliveries arrive. Therefore, the supplying company and the customer must both agree on a time window, which ideally is rather short, during which delivery is guaranteed. Typically, a capacitated Vehicle Routing Problem with Time Windows forms the underlying optimization problem of the AHD system. In this work, we consider an AHD system that runs the online grocery shopping service of an international grocery retailer. The ordering phase, during which customers place their orders through the web service, is the computationally most challenging part of the AHD system. The delivery schedule must be built dynamically as new orders are placed. We propose a solution approach that allows to (non-stochastically) determine which delivery time windows can be offered to potential customers. We split the computations of the ordering phase into four key steps. For performing these basic steps we suggest both a heuristic approach and a hybrid approach employing mixed-integer linear programs. In an experimental evaluation we demonstrate the efficiency of our approaches

Incorporating risk in field services operational planning process

© Springer Nature Switzerland AG 2018. This paper presents a model for the risk minimisation objective in the Stochastic Vehicle Routing Problem (SVRP). In the studied variant of SVRP, service times and travel times are subject to stochastic events, and a time window is constraining the start time for service task. Required skill levels and task priorities increase the complexity of this problem. Most previous research uses a chance-constrained approach to the problem and their objectives are related to traditional routing costs whilst a different approach was taken in this paper. The risk of missing a task is defined as the probability that the technician assigned to the task arrives at the customer site later than the time window. The problem studied in this paper is to generate a schedule that minimises the maximum of risks and sum of risks over all the tasks considering the effect of skill levels and task priorities. The stochastic duration of each task is supposed to follow a known normal distribution. However, the distribution of the start time of the service at a customer site will not be normally distributed due to time window constraints. A method is proposed and tested to approximate the start time distribution as normal. Moreover, a linear model can be obtained assuming identical variance of task durations. Additionally Simulated Annealing method was applied to solve the problem. Results of this work have been applied to an industrial case of SVRP where field engineering individuals drive to customer sites to provide time-constrained services. This original approach gives a robust schedule and allows organisations to pay more attention to increasing customer satisfaction and become more competitive in the market

Universal DNA methylation age across mammalian tissues.

Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals

Integrated Planning of Order Capture and Delivery for Attended Deliveries in Metropolitan Areas

The ongoing boom in e-commerce increases the importance of profitable and customer-oriented delivery services. Particularly in metropolitan areas, the high population density offers great potential for e-commerce, while uncertain demand and traffic conditions increase planning uncertainty. This contribution focuses on e-commerce delivery fulfillment (e-fulfillment) for attended last-mile delivery services in metropolitan areas. As the customer needs to be present for deliveries of groceries, for example, a service time window has to be agreed upon already when a customer’s order is accepted. We consider service time windows as a scarce resource and as the critical interface between order capture and order delivery. To optimally utilize this scarce resource, we propose combining concepts of revenue management and vehicle routing to extend tactical and operational planning for e-fulfillment. We define the research problem and provide a perspective on integrated planning for attended deliveries. Furthermore, we present the design of a virtual laboratory to support benchmarking in e-fulfillment research. To ensure realistic experimental settings, we plan to incorporate real-world data provided by a major e-grocery in Germany

Panel Session Conceptual Modelling for Archaeology: Discussión

Comunicación presentada en la 39th Annual Conference of Computer Applications and Quantitative Methods in Archaeology (CAA 2011), celebrada en Pekín del 12 al 16 de abril de 2011.Peer Reviewe

Time-Dependent Travel-Time Constrained Inventory Routing Problem

International audienc

Levers of logistics service providers’ efficiency in urban distribution

This paper identifies the most important factors that influence the productivity of the urban fleet of a Logistics Service Provider (LSP). Through a regression analysis on a dataset from distribution warehouses of a single LSP, three main levers are shown to have significant impacts on productivity, namely the network design, the vehicle loading strategy, and the business environment wherein the operations are carried out. This paper contributes to bridge the gap about the lack of works addressing the efficiency of LSPs operating in urban areas, by performing a detailed empirical analysis instead of taking an aggregated company perspective