ITS Berkeley

The Productivity of Multipurpose Seaport Terminals

Carlos Daganzo
1990

This paper studies the peculiar queueing problem that arises at multipurpose port terminals serving two traffic types. Primary (liner ship) traffic obeys a schedule and has absolute priority on the use of the multipurpose facilities. Secondary (tramp) traffic, which arrives at random, can also be served elsewhere in the port. Secondary traffic is routed to the multipurpose berths only if doing so does not delay any primary ship. (The port knows a fair amount ahead of time the arrival times of these ships and the likely service times of both liners and tramps). The goal is to obtain simple...

Some Properties of Polling Systems

Carlos Daganzo
1990

This paper examines the properties of single server queueing systems with customers of several types, where the server rotates its effort among the customer classes and serves all the customers that have accumulated for each class before moving on to the next. The paper shows that expressions for the first two moments of the queue lengths, and for the mean waiting times, can be developed from two simple properties of the arrival and service processes. The properties, which include existing models as special cases, seem plausible descriptors of the complex arrival and service processes that...

A Branch and Bound Solution Method for the Crane Scheduling Problem

Peterkofsky, Roy I.
Carlos Daganzo
1990

Typical cargo ships spend 60% of their time in port, costing their owners about $1000 per hour. In this paper, we attack such costs with a method to speed loading and unloading. We model the need for container handling as generic “work,” which cranes can do at a constant rate. Each hold of each ship has a given amount of this work and cranes can interrupt their work on individual holds without any loss of efficiency. In the parlance of scheduling theory, this constitutes an “open shop” with parallel, identical machines, where jobs consist of independent, single-stage, preemptable tasks....

Analysis of Baggage Sorting Schemes for Containerized Aircraft

Robusté, Francesc
Carlos Daganzo
1992

Baggage transfer is a critical factor in determining connecting schedules at hub airports. This paper examines the potential benefits of “ramp transfers”-bags that bypass the hub sorting facility because they have been presorted at their point of origin. It presents three idealized baggage presorting strategies for containerized (wide-bodied) aircraft. These strategies are compared under a range of conditions, and are then integrated in a computer tool that can handle more complex problems. Presorting baggage at the origin by final destinations or groups of final destinations may be...

Optimal Pricing Policies for Temporary Storage at Ports

de Castilho, Bernardo
Carlos Daganzo
1991

Centralized Hub‐Terminal Geometric Concepts. II: Baggage and Extensions

Robusté, Francesc
Carlos Daganzo
1991

This paper shows how the geometric concepts examined in the first paper perform for baggage operations, recognizing that passengers and bags travel different distances through the airport. The paper shows that the most effective geometry (minimizing
...

Synchronizing Production and Transportation Schedules

Blumenfeld, Dennis E.
Burns, Lawrence D.
Carlos Daganzo
1991

This paper examines whether it is cost-effective to synchronize production and transportation schedules on a production network. The network considered consists of one origin and many destinations. The origin produces parts that are shipped directly to each destination. Trade-offs between production set-up, freight transportation, and inventory costs on the network are analyzed, and total costs are compared for synchronized and independent schedules. The paper focuses on a simple production system, which can be modeled analytically and which allows the basic issues in synchronizing...

Bounding the VRP Distance Before Knowing the Location of Points

Carlos Daganzo
1991

This note presents upper bounds for the minimum distance needed to visit n points in a unit circle, with a vehicle fleet based at its center and allowed to visit a maximum of q points per vehicle tour. The paper shows that the minimum distance can never exceed: [2n/q]+ + pi q. If points are randomly and uniformly distributed, and travel can only take place on a ring-radial network, the paper also proves that for q = 0(n**beta), 0 less than beta less than 1/2, the average minimum distance does not exceed: [4n/3q] + 0.82(pi n)**1/2 + 0(q). For the Euclidean metric, it is claimed that a...

Restricting Road Use Can Benefit Everyone

Carlos Daganzo
1992

This paper seeks congestion reduction schemes that do not penalize anyone. It shows that a combination of rationing and pricing (unlike congestion pricing alone) can benefit everyone even if the collected revenues are not returned to the population. The simple conditions under which this is possible are identified. Little data are needed to choose a proper policy. Examples are given.

Restricting Road Use Can Benefit Everyone, Part II: Time-of-Day Restrictions that Encourage Earlier Arrivals

Carlos Daganzo
1992

This research considers a less restricting rationing scheme where a restriction would mean that passage through the bottleneck is banned after a certain time of the day (e.g. the start of the rush hour) but not before that time. Conservatively, we assume that the ban remains in force even after the conclusion of the rush, although in practice one would like to terminate it earlier. (This assumption limits the benefits that can be gained from control as it discourages people from delaying their arrival in order to avoid the queue.) Despite this inefficiency, the scheme is shown to...