Staffing problems and symmetric integer programs

Issued as Final project report, Project no. E-24-63

The best shape for a crossdock

The article of record as published may be found at http://dx.doi.org/10.10.1287/trsc.1030.0077Within both retail distribution and less-than-truckload transportation networks crossdocks vary greatly in shape. Docks in the shape of an I, L, or T are most common, but unusual ones may be found, including those in the shape of a U, H, or E. Is there a best shape? We show that the answer depends on the size of the facility and on the pattern of freight flows inside. Our results suggest that many large crossdocks in practice suffer from poor design that increases labor costs on the dock.Office of Naval ResearchNational Science FoundationN00014-95-1-0380 (ONR)DMI-0008313 (NSF)N00014-00-WR-20244 (ONR

Chaos and Convergence on Bucket Brigade Assembly Lines

One way to coördinate the efforts of workers along an assembly line that has fewer workers than work stations is to form a bucket brigade. Each worker in a bucket brigade simultaneously assembles a single item (an instance of the product) along the line. The worker carries the item from work station to work station until either he hands off his item to a downstream co-worker or he completes the work for his item. The worker then walks back to get another item, either from his co-worker upstream or from a buffer at the beginning of the line. The most notable application of bucket brigades is to coördinate workers to pick products for customer orders in distribution centers, as reported in Bartholdi and Eisenstein (1996b) and Bartholdi et al. (2001). Bucket brigades have also been used in the production of garments, the packaging of cellular phones, and the assembly of tractors, large-screen televisions, and automotive electrical harnesses (see Bartholdi and Eisenstein (1996a,b, 2005), and Villalobos et al. (1999a,b)). In the Normative Model of bucket brigades (Bartholdi and Eisenstein 1996a) the work content of the product is assumed to be deterministic and to be continuously and evenly

Amenability of groups and GG-sets

This text surveys classical and recent results in the field of amenability of groups, from a combinatorial standpoint. It has served as the support of courses at the University of G\"ottingen and the \'Ecole Normale Sup\'erieure. The goals of the text are (1) to be as self-contained as possible, so as to serve as a good introduction for newcomers to the field; (2) to stress the use of combinatorial tools, in collaboration with functional analysis, probability etc., with discrete groups in focus; (3) to consider from the beginning the more general notion of amenable actions; (4) to describe recent classes of examples, and in particular groups acting on Cantor sets and topological full groups

Independent agents and self-organizing logistics system

Issued as final reportNavy Office of Naval Researc

A ROUTING SYSTEM BASED ON SPACEFILLING CURVES

We describe some fundamental issues in routing and distribution and illustrate them in a case study, which shows how to build a commercial-quality routing sys-tem in one day and with no computer. 1 Routing and distribution Distribution is the getting the product to the customer. The management of distribu-tion has continued to change rapidly after deregulation in the early 1980’s and with the development of new technologies such as on-board computers, radio, and global-positioning systems. It is cheapest to ship long distance by train and so railroads are capturing an in-creasing amount of long-haul freight. Small, urgently-needed goods move by more expensive plane. But currently the bulk of freight, and all local freight, is handled by truck. The basic problem faced by a distribution manager, then, is this: How best to coördinate a fleet of vehicles to deliver goods to their destination 1. One would like to accomplish many things, some of which work at cross-purposes, such as • Allocate the goods among the vehicles so that not too many trucks are required

Production lines that balance themselves

Issued as Report, and Final report, Project no. E-24-61

Static and dynamic balance of rotor stacks

Issued as Final technical report, Project E-24-X5