In this paper, we study a multi-echelon uncapacitated lot-sizing problem in series (mULS), where the output of the intermediate echelons has its own external demand, and is also an input to the next echelon. We propose a polynomial-time dynamic programming algorithm, which gives a tight, compact extended formulation for the two echelon case (2-ULS). Next, we present a family of valid inequaliti...

We present a two-echelon van-based robot last-mile pickup and delivery system in urban settings. Robots can visit areas with van access restrictions, such as pedestrianized or university campuses. The stops at parking nodes to drop off and/or pick up its robot, replenish swap robot’s battery if needed. Five van/robot cases are considered, according the roles plays process of pickup/delivery whe...

In this paper, we study novel variants of the well-known two-echelon vehicle routing problem in which a truck works on first echelon to transport parcels and fleet drones intermediate depots while second echelon, are used deliver from customers. The objective is minimize completion time instead transportation cost as classical problems. Depending context, drone can be launched at an depot once ...

The Two-Echelon Routing Problem constitutes a class of combinatorial optimization problems with applications in many different fields such as city logistic planning, intermodal transportation, postal and parcel delivery distribution systems and so on. This thesis contains: a survey of the main contributions related to the two-echelon routing, focusing on the Two-Echelon Location Routing Problem...

An arborescent distribution system is a multi-level system in which each installation receives input from a unique immediate predecessor and supplies one or more immediate successors. In this paper, it is shown that a distribution system with an arborescent structure can also be modelled using an echelon stock concept where at any instant the total echelon holding cost is accumulated at the sam...

Nowadays, offering extended warranty is considered as a lucrative source of income from the perspective of the after-sale service providers. Meanwhile, the main concern is presence or absence of base warranty and strategies adopted by the manufacturer during this period. Moreover, extended warranty structure must be responsive and customer oriented, which not only control the services cost but ...

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium ((99m)Tc) and vital blue dyes are among t...

Fisher and Fisher (3) and Agostino and Clifton (1, 2) have shown that the metastatic "take" of tumor cells given intra venously to animals can be reduced by prior heparinization. However, if heparinization were to reduce the filtration efficiency of the first echelon lymph nodes for lymphatic métastasesfrom a localized tumor, this useful action would be counterbalanced. To study the effect of ...

By nearly every metric—cost, power consumption, capacity, bandwidth, and latency—memory is emerging as one of the most constrained resources on compute nodes of HPC systems [12]. These constraints will force future systems to abandon flat SMP memory space in favor of a more distributed NUMA design, even within a socket. With exponentially increasing numbers of cores per node, the overhead of gl...

The Two-Echelon Vehicle Routing Problem (2E-VRP) is an extension of the classical VRP where the delivery from a single depot to customers is managed by routing and consolidating the freight through intermediate depots called satellites. We presented several meta-heuristics based on separating the first and second level routing problems and solving iteratively the two resulting routing subproble...