Freight and Goods Movement

A Routing Model for Pickups and Deliveries: No Capacity Restrictions on the Secondary Items

Daganzo, Carlos F.
Hall, Randolph W.
1993

This paper examines a routing problem in which vehicles from a single depot cover a large area, where randomly located customers request pickup and delivery service. The paper assumes that each vehicle must serve its deliveries before it collects any pickups, that vehicles do not need to return to the depot between delivery and collection, and that each vehicle can serve at most C deliveries, but an unlimited number of pickups. This paper does not propose a detailed algorithm; rather, it discusses the pros and cons of various broad routing schemes, and quantifies their performance with...

The Variance of the Number of Customers in an Infinite-Server Queueing System with an Arbitrarily Correlated Arrival Process

Daganzo, Carlos F.
Diez-Roux, Esteban
1995

Motivated by a container storage problem at seaports, this paper examines the infinite-server queueing model with a (second order) stationary but arbitrarily correlated arrival process. It starts with a description of the application context, including an explanation of why non-standard inputs and service times arise in certain container storage problems. As further illustration, formulas characterizing the input and service processes for a particular situation are then presented and justified, together with the simple container accumulation variance formula that follows from the general...

Impact of Manufacturing Response Time on Retailer Inventory

Blumenfeld, Dennis E.
Daganzo, Carlos F.
Frick, Michael C.
Gonsalvez, David J.A.
1999

Retailers receiving items from a manufacturer carry inventory to meet customer demand. As items are sold, a retailer orders new items to replenish the inventory. Once an order is placed, there is a time taken for the items to be delivered to the retailer. This time is the manufacturing response time. It includes processing, production, and delivery times. These different components of time can result in response times that are long and uncertain. This paper develops a queueing model for analysing how manufacturing response time affects the inventory needed at retailers to meet demand. The...

Deferred Item and Vehicle Routing within Integrated Networks

Smilowitz, Karen R.
Atamtürk, Alper
Daganzo, Carlos F.
2003

This paper studies the possible integration of long-haul operations by transportation mode and service level (defined by guaranteed delivery time) for package delivery carriers. Specifically, we consider the allocation of deferred items to excess capacity on alternative modes in ways that allow all transportation modes to be utilized better. Model formulation and solution techniques are discussed. The solution techniques presented produce solutions for large-scale problem instances with up to 141 consolidation terminals and 17 breakbulk terminals. Allowing deferred items to travel by air...

Reducing Ship Turn-Around Time Using Double-Cycling

Goodchild, A. V.
Daganzo, Carlos F.
2004

Double cycling improves efficiency by unloading and loading a ship simultaneously; using wasted crane moves to transport containers. This paper demonstrates that double cycling can reduce ship turn-around time through this efficiency improvement. The paper describes the nature of the double cycling problem and, for a given loading-plan, quantifies the benefits using a greedy algorithm. The relationship between the benefits of double cycling, and the problem parameters is analyzed using simple formulas and a simulation program. This paper demonstrates that double cycling can create...

On the Stability of Supply Chains

Daganzo, Carlos F.
2004

This paper examines the stability of decentralized, multistage supply chains under arbitrary demand conditions. It looks for intrinsic properties of the inventory replenishment policies that hold for all customer demand processes and for policies with desirable properties. It is found that the overall conditions experienced by suppliers several stages removed from the final customer, e.g., the variances of the orders they receive and the inventories they keep, depend on the policy much more than on the demand process. A policy-specific but demand-independent upper bound for the order...

Some Properties of Decentralized Supply Chains

Ouyang, Yanfeng
Daganzo, Carlos F.
2005

This paper analyzes the bullwhip effect in decentralized, linear and time-invariant (LTI) supply chains. It generalizes existing results by broadening the class of policies and customer demand processes under consideration. The supply chain is modeled as a single-input, singleoutput control system driven by arbitrary demands. The paper discusses the appropriateness of various metrics for the bullwhip effect, and derives analytical conditions to predict its presence independently of the demand process. The paper also gives a formula for the variance of the order stream at any stage when the...

A Review of Green Logistics Schemes Used in Cities Around the World

Geroliminis, Nikolaos
Daganzo, Carlos F.
2005

Freight carriers strive to provide higher levels of transportation service with lower costs. However, the economic and environmental viability of cities are negatively affected by the present organization of urban goods distribution. Can these two competitive goals be harmonised to create efficient and environmentally friendly urban logistics systems? This paper presents several examples of “green logistics” schemes tried in a number of forward-looking cities around the world. The review highlights the basic qualitative ideas of these schemes and the results of field tests. Most of the...

Bullwhip Effect in Decentralized Supply Chains

Daganzo, Carlos F.
Ouyang, Yanfeng
2006

This paper analyzes the bullwhip effect in decentralized, linear and time-invariant (LTI) supply chains. It generalizes existing results by broadening the class of policies and customer demand processes under consideration. The supply chain is modeled as a single-input, single-output control system driven by arbitrary demands. The paper discusses the appropriateness of various metrics for the bullwhip effect, and derives analytical conditions to predict its presence independently of the demand process. The paper also gives a formula for the variance of the order stream at any stage...