Active repositioning of storage units in Robotic Mobile Fulfillment Systems

In our work we focus on Robotic Mobile Fulfillment Systems in e-commerce distribution centers. These systems were designed to increase pick rates by employing mobile robots bringing movable storage units (so-called pods) to pick and replenishment stations as needed, and back to the storage area afterwards. One advantage of this approach is that repositioning of inventory can be done continuously, even during pick and replenishment operations. This is primarily accomplished by bringing a pod to a storage location different than the one it was fetched from, a process we call passive pod repositioning. Additionally, this can be done by explicitly bringing a pod from one storage location to another, a process we call active pod repositioning. In this work we introduce first mechanisms for the latter technique and conduct a simulation-based experiment to give first insights of their effect

A Deep Generative Model of Vowel Formant Typology

What makes some types of languages more probable than others? For instance, we know that almost all spoken languages contain the vowel phoneme /i/; why should that be? The field of linguistic typology seeks to answer these questions and, thereby, divine the mechanisms that underlie human language. In our work, we tackle the problem of vowel system typology, i.e., we propose a generative probability model of which vowels a language contains. In contrast to previous work, we work directly with the acoustic information -- the first two formant values -- rather than modeling discrete sets of phonemic symbols (IPA). We develop a novel generative probability model and report results based on a corpus of 233 languages.Comment: NAACL 201

Service Parts Inventory Control with Lateral Transshipment that Takes Time

In equipment-intensive industries such as truck manufacturing, electronics manufacturing, photo copiers, and airliners, service parts are often slow moving items for which, in some cases, the transshipment time is not negligible. However, this aspect is hardly considered in the existing spare parts literature. We assess the effect of non-negligible lateral transshipment time on various aspects of spare parts inventory control. Furthermore, we introduce customer-oriented service levels by taking the uncommitted pipeline stocks into account. A case study in the dredging industry shows that lateral transshipment may lead to lower system performance, which supports the results from some recent studies. Furthermore, we find that considerable savings can be obtained when we include the uncommitted pipeline stocks in both base stock allocation and lateral transshipment decisions.inventory control;METRIC;customer-oriented service level;lateral transshipment