Richard Lee Storch

An algorithm for scheduling a chemical processing tank line

Abstract This paper presents a model and an algorithm for scheduling a system in which parts are processed through a chemical processing tank line. The tank line is equipped with one piece of material-handling equipment. The tank line is modelled with a mixed integer linear programming formulation. The formulation is then used to develop a heuristic algorithm. The algorithm generates the optimum or near optimum schedule and is easy to apply in practice where no defectives are permitted.

Improving flow to achieve lean manufacturing in shipbuilding

As the world has moved closer to a global economy, competition between manufacturing companies has also become global. This increasingly competitive environment has led tointense study ofthe companies that are at the top in terms of competitive position. As a result of this study, the concepts of lean thinking and lean manufacturing have been described. The shipbuilding industry, especially outside Japan, has not yet responded to the need to apply these principles. This paper explores the potential application of one of these principles, flow, to the shipbuilding industry. It proposes an approach to move the industry closer tolean manufacturing in terms offlow, and offers a metric by which to determine how close to ideal flow a shipbuilding system is. The basis for the establishment of lean thinking in shipbuilding is the appropriate application of group technology through the use of a product-oriented workbreakdown structure. This paper also considers how these ideas may be generalized to any large assem...

Pipe-routing algorithm development: case study of a ship engine room design

Abstract This study presents an automatic pipe-routing algorithm accommodating all major detail-design facets. First, the algorithm uses pattern-match methods to provide candidate paths. A cell-generation method is developed which satisfies geometric constraints. This makes the generation and evaluation of paths effective and efficient. Next, various non-geometric aspects, such as material costs, installation costs, and valve operability, are assessed from a fiscal point of view. Then, from a tree of combinations, the algorithm chooses an appropriate path for each pipeline from the candidate paths. Finally, a general approach toward detail design automation is suggested. The software implementation was done with Microsoft Visual Basic 6.0 and Access 2000, Heide Corporation Intent! for AutoCAD 2000, and AutoDesk AutoCAD 2000.

Challenges in computer applications for ship and floating structure design and analysis

This paper presents a review on the key research areas in the design and analysis of ships and floating structures. The major areas of computer application are identified in several stages of ship/floating structure design and analysis with the principal emphasis on the methodologies, the modeling, and the integration of the design and analysis process. The discussion addresses some of the key challenges in computer applications for ship and floating structure design and analysis, and reports on the emerging trends in the research, design and industrial application.

Heterogeneous dispatching rules in job and flow shops

Abstract This paper reports the results of a study of the use of heterogeneous dispatching rules for the scheduling of work in a job shop. The methodology employed included discrete event simulation, using rule combinations determined by prior genetic algorithm searches and generalization using neural networks. Eight dispatching rules were considered, including first in first out (FIFO), earliest due date ( EDD), shortest processing time (SPT), slack/ number of operations (SLK), critical ratio (CR), modified due date (MDD), modified operation due date (MOD), and apparent tardiness cost (ATC). A three-machine job shop was studied, in which three work organizations were employed, pure flow (fixed sequence), pure job shop ( random sequence), and a hybrid shop where flow is random but with unequal probabilities. Three levels of machine loading were used and average tardiness was used as the performance measure. In most cases, modified due date and apparent tardiness cost were the best rules. The application o...

Overview of ship‐design expert systems

Expert systems constitute a branch of artificial intelligence, and their unique characteristics enable computer systems to perform at the level of a human expert by the use of algorithms that can capture domain-specific knowledge. Through an extensive survey of research about ship-design expert systems, we conclude that although development and implementation of expert systems for ship design offer substantial barriers, the shipbuilding industry needs them nonetheless. We examine the major reasons that use of expert systems in this industry has lagged behind. These include the problems of integration with existing computer-aided design systems, problems of knowledge representation and sizable development costs. We discuss in detail some key factors that can lead to the solution of these problems.

Asynchronous stochastic learning curve effects in engineering-to-order customisation processes

As industrial technology progresses from tailored customisation and mass production all the way to mass customisation, the demand for faster order-to-delivery time keeps increasing, especially for those products that require lengthy customised engineering-to-order (ETO) tasks among multiple partners. Products such as commercial airplanes and ocean vessels, which have delivery demands before the integrated production system has reached a steady production pace, involve partners progressing through their engineering tasks at asynchronous stochastic learning curve (ASLC) rates. This paper aims to contribute to the research by revealing the novel ASLC model and addressing ETO-related processes. An application of the ASLC model in an ETO case study by using sanitised real production data is also presented.

An example for scheduling a chemical processing tank line

This paper presents an algorithm for scheduling a chemical processing line with one piece of material handling equipment to transfer jobs through the line. An easy to use scheduler is developed which can be used to schedule a line or analyze the line design parameters during the design stage to achieve the maximum throughput while not allowing defects.

A non-sequential just-in-time simulation model

Non-sequential Just-in-Time discrete-event simulation logic is presented. This logic allows for batches of parts to be routed from any operation to any other operation within the same facility or manufacturing cell. In addition, this logic is able to accommodate large batch-to-batch variations in processing times. Some initial results based on data collected from a manufacturer of industrial lift equipment are presented.

The collaborative engineering process within the framework of the virtual enterprise

The virtual enterprise has become a prominent organizational structure under which small and medium sized enterprises having strong, narrowly focused core competencies can band together to accomplish large projects. Great strides have been made in the evolution of the virtual enterprise as a collaborative engineering environment; however, in many cases, a key component of the virtual enterprise is missing that allows for the enterprise to stay focused on project goals, rather than concentrate on conflict resolution among its members. This component is the project manager. By having a project manager take responsibility for the management of the project, the virtual enterprise can maintain its collaborative environment and its members can remain focused on the goals of the project.