Richard J. Linn

Storage space allocation in container terminals

Container terminals are essential intermodal interfaces in the global transportation network. Efficient container handling at terminals is important in reducing transportation costs and keeping shipping schedules. In this paper, we study the storage space allocation problem in the storage yards of terminals. This problem is related to all the resources in terminal operations, including quay cranes, yard cranes, storage space, and internal trucks. We solve the problem using a rolling-horizon approach. For each planning horizon, the problem is decomposed into two levels and each level is formulated as a mathematical programming model. At the first level, the total number of containers to be placed in each storage block in each time period of the planning horizon is set to balance two types of workloads among blocks. The second level determines the number of containers associated with each vessel that constitutes the total number of containers in each block in each period, in order to minimize the total distance to transport the containers between their storage blocks and the vessel berthing locations. Numerical runs show that with short computation time the method significantly reduces the workload imbalance in the yard, avoiding possible bottlenecks in terminal operations.

Dynamic crane deployment in container storage yards

Storage yards at container terminals serve as temporary buffers for inbound and outbound containers. Rubber tyred gantry cranes (RTGCs) are the most frequently used equipment in yards for container handling. The efficiency of yard operations heavily depends on the productivity of these RTGCs. As the workload distribution in the yard changes over time, dynamic deployment of RTGCs among storage blocks (container stacking areas) is an important issue of terminal operations management. This paper addresses the crane deployment problem. Given the forecasted workload of each block in each period of a day, the objective is to find the times and routes of crane movements among blocks so that the total delayed workload in the yard is minimized. The problem is formulated as a mixed integer programming (MIP) model and solved by Lagrangean relaxation. To improve the performance of this approach, we augment the Lagrangean relaxation model by adding additional constraints and modify the solution procedure accordingly. Computational experiments show that the modified Lagrangean relaxation method generates excellent solutions in short time.

A decision support system for operations in a container terminal

We describe a variety of inter-related decisions made during daily operations at a container terminal. The ultimate goal of these decisions is to minimize the berthing time of vessels, the resources needed for handling the workload, the waiting time of customer trucks, and the congestion on the roads and at the storage blocks and docks inside the terminal; and to make the best use of the storage space. Given the scale and complexity of these decisions, it is essential to use decision support tools to make them. This paper reports on work to develop such a decision support system (DSS). We discuss the mathematical models and algorithms used in designing the DSS, the reasons for using these approaches, and some experimental results.

Rubber tired gantry crane deployment for container yard operation

Container terminals competitiveness is generally measured by the vessel discharging and loading time. The shore crane operation has attracted a number of research works. However, yard operation management has been very much experience based and did not receive much attention until last decade. This paper presents an algorithm and a mathematical model for the optimal yard crane deployment. The potential of the model in optimizing yard crane deployment was tested with a set of real operation data extracted from a major container yard terminal.

A heuristic for dynamic yard crane deployment in a container terminal

Rubber Tired Gantry Cranes (RTGCs) are the most widely used pieces of equipment in the Hong Kong sea-freight container yards. Workload distribution in the yard changes continuously over time. The dynamic deployment of RTGCs is an important issue in yard operation management. This paper investigates the dynamic crane deployment problem with the objective of determining the crane deployment frequency and routes over a planning horizon to minimize the total workload overflow. The problem is formulated as a mixed integer programming model. A heuristic algorithm is then developed to solve problems of practical sizes. The heuristic quickly finds a near optimal solution for crane deployment operation.

Supplier Selection Based on Process Capability and Price Analysis

Supplier selection is an important part of supply chain management. Among the numerous methods that have been proposed, process capability index is considered to be the most effective technique for identifying quality parts. However, supplier selection should be carried out on the basis of quality and cost together. There is no easy tool available to evaluate the price and quality in an integrated manner. In this article, a new approach to supplier selection using capability index and price comparison (CPC) chart is presented. The CPC chart integrates the process capability and price information of multiple suppliers and presents them in a single chart. It provides a simple but effective method to consider quality and price simultaneously in the supplier selection process.

An intelligent management system for technology management

Current approaches to technology management express the need to manage technology systematically from both strategic and operational perspectives. However, considerable ambiguity seems to prevail over the exact way of managing it. This paper presents an object-oriented intelligent management system for technology management by using the methodology of Intelligent Engineering. A hierarchical model is proposed to manage the complex and ill-formulated technology management process. The design and implementation for the Intelligent Management System for Technology Management (IMS-TM) using the hierarchical model are described. A meta-system, which serves as IMS-TM kernel to manage and control the operation of the systems, is presented. This intelligent management system framework has been implemented in a government technology supervision bureau to assist the management of their technology development policy and project management.

Process Capability Improvement for Multistage Processes

While the quality control procedures for multistage has been considerably studied, multistage process capability analysis has not been explored much at all. Fostering on the recent development of the multistage process variation transmission model, a multistage process capability analysis algorithm is developed to prioritize process improvement efforts. The application of algorithm is demonstrated with two 2-stage industrial process examples and a 4-stage process example for its expandability.

EFFICIENT HEURISTICS FOR DRILLING ROUTE OPTIMIZATION IN PRINTED CIRCUIT BOARD MANUFACTURING

A multi-layer printed circuit board (PCB) consists of multiple layers of circuitry sandwiched together with insulating laminate, such as FR-4, in between layers. The connections among the layers of circuits are made by the electroplated via holes which are drilled one by one. With miniaturization of the printed circuit design and increase in circuit density, the number of holes per panel has increased significantly, and minimizing the drill travel time becomes an attractive way of increasing PCB production capacity. Drill travel time minimization is a classical traveling salesman problem (TSP). There have been several studies addressing the efficiency of different algorithms in solving TSPs. However, the number of nodes involved in these studies is far less than the modern PCB design requirement. This study is to evaluate the efficiency of documented combinatorial optimization algorithms for PCB drilling route minimization. Four algorithms — simulated annealing, nearest neighbor search, sequential search and ranged sequential search — are evaluated for best improvement in drilling route length. Ranged sequential search and nearest neighbor are found to be the better heuristics among them. The performance can be further improved if a composite approach of pairing two algorithms is used. However, computation time may become a constraint.

Analysis of process errors and production yield for surface mounted printed circuit assembly

Concurrent engineering in electronic manufacturing industries assures product quality through the integration of product and process design. To maximize the concurrent engineering effort, the fundamental understanding of the relationship between product and process quality, especially the process capabilities and propagation of in-process errors, must be better developed. This paper presents a process error model which is intended for production yield evaluation during the printed circuit design stage by considering the process errors in the device packaging, printed circuit board manufacturing, and assembly equipment process capability. An analysis of the effects of in-process errors in the pick-and-place process is described. The application of Monte Carlo simulation in estimating the surface mounted technology printed circuit assembly yield is also demonstrated.