• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.298-301
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• 2001

In semiconductor manufacturing, wafer fabrication is the most complicated and important process, which is composed of several hundreds of process steps and several hundreds of machines involved. The productivity of the manufacturing mainly depends on how well they control balance of WIP flow to achieve maximal throughput under short manufacturing cycle time. In this paper mathematical formulation is suggested for the stepper scheduling, in which cycle time reduction and maximal production is achieved.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.939-954
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• 1995

We propose a policy for controlling the release of raw wafers into the semiconductor wafer fabrication lines. The proposed policy exploits up-to-date factory floor information gathered by tracking systems used to calculate the time and amount of a new release to minimize mean flow times and mean tardiness while maintaining the maximum output rates of the system. Extensive computer experiments show that the proposed policy results in significant improvements for the same output rates compared to existing release rules.

• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.437-450
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• 2006

The Contour Crafting(CC) process, which has been developed at the University of Southern California, aims at automated construction of whole houses as well as sub-components. For this purpose, new trowel mechanism is basically needed in order to fabricate the true 3D shape. This paper presents our concepts and initial investigation of 3D free form fabrication using the pivoting side trowel. Specifically, the status of research and development of the processand experiments with ceramics materials, and its potential application areas are detailed.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.4
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• pp.105-114
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• 2003

This paper considers a single facility scheduling problem for the fabrication of components supporting the subsequent assembly into products. Each product consists of two types of components, one is common to all products and the other is unique to itself. The unique components are processed individually and the common components are processed in batches, and a distinct setup is incurred for the production of a batch of common components. Under the so-called “batch availability” environment, we propose an efficient dynamic programming(DP) procedure for the optimal sequencing and batching schedule with minimum total completion times of products in the situation that each product is said to be complete if both common and unique components of the product are finished. Computational results show that the proposed DB procedure is more efficient than the previous work which has considered the same problem as this paper.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1081-1087
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• 2009

An automatic construction system in Korea is now at the stage of the full automation like in Japan, and an actual pilot project is going to be built in 2009. However, in developing a new construction system that has never been implemented before, there is a need to assess the performance and to consider the uncertainty of the system. The program evaluation and review technique (PERT) allows dealing with this uncertainty. Thus, this paper implements an analysis of the process of steel fabrication and makes suggestions for time-related problems arising from the analysis. The time required for steel erection by the automatic system was compared with that in the traditional method. In the result, finding out another construction process and improving robot performance were proposed to resolve the problems. The results will contribute to promoting the development of an efficient system for the new automatic construction system.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.401-406
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• 1988

Various types and huge volume of information such as process instructions, work-in process and parametric data are created in a wafer fabrication process and should be provided to personnels inside or outside the facility. This article describes design criteria and functional description on the information system for small-scale wafer fabrication process to accomplish paperless fab and to support efficient fab management.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1107-1112
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• 2009

To design and build a deformed building, new approaches and technologies are required, in which a design approach with parametric and generative technology is used for design and for building it, computer based fabrication technology. Even if parametric design technology is not a state of the art thing, the technology is still used widely, in order to effect the efficiency and furthermore it will continue to be innovated upon continuously. To cope with the limitation of it, the generative design system is developed. Deformed building design requires new methodology to overcome the limitations of conventional ways, which have difficulties to create enough design alternatives to explore satisfied design solutions order to deformed design have geometrical complexity and dramatically increased amount of data. Hence the generative design system can be a cutting edge methodology to solve it. However we should consider how to build the design in the real world. For this, the computer based fabrication technology which is used in mechanical industry is required to introduce to architecture and construction domain for efficiency. In this research, the methodology is modeled and tested with Bezier surface based shell structure.

• Journal of Ocean Engineering and Technology
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• v.32 no.2
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• pp.106-115
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• 2018

The forward and afterward parts of ships and offshore structures are designed to improve the fuel consumption performance. These are made of curved plates with a large thickness. If a fabricated curved plate has some dimensional errors, a lot of additional cost is incurred in the assembly process. Thus, an accurate dimensional assessment is very important for fabrication. In this paper, we propose an assessment method for the dimensional quality management of curved plates. This can be applied to data measured using a variety of three-dimensional instruments, with boundary measurement points automatically classified and sorted to create a measurement surface. The assessment is evaluated after matching the CAD surface and the measured surface considering constrained conditions. The fabrication assessment is evaluated as a probability of how much the tolerance is satisfied.

• Smart Structures and Systems
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• v.30 no.1
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• pp.35-47
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• 2022

Data-driven engineering is crucial for information delivery between design, fabrication, assembly, and maintenance of prefabricated structures. Design for manufacturing and assembly (DfMA) is a critical methodology for prefabricated bridge structures. In this study, a novel concept of digital engineering model that combined existing knowledge of DfMA with object-oriented parametric modeling technologies was developed. Three-dimensional (3D) geometry models and their data models for each phase of a construction project were defined for information delivery. Digital design models were used for conceptual design, including aesthetic consideration and possible variation during fabrication and assembly. The seismic performance of a bridge pier was evaluated by linking the design parameters to the calculated moment-curvature curves. Control parameters were selected to consider the tolerance control and revision of the digital models. Digitalized fabrication of the prefabricated members was realized using the digital fabrication model with G-code for a concrete printer or a robot. The fabrication error was evaluated and the design digital models were updated. The revised fabrication models were used in the preassembly simulation to guarantee constructability. For the maintenance of the bridge, the as-built information was defined for the prefabricated bridge piers. The results of this process revealed that data-driven information delivery is crucial for lifecycle management of prefabricated bridge piers.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1101-1106
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• 2005

The purpose of this study was to develop a process management system to manage ingot fabrication and the quality of the ingot. The ingot is the first manufactured material of wafers. Operating data (trace parameters) were collected on-line but quality data (measurement parameters) were measured by sampling inspection. The quality parameters were applied to evaluate the quality. Thus, preprocessing was necessary to extract useful information from the quality data. First, statistical methods were employed for data generation, and then modeling was accomplished, using the generated data, to improve the performance of the models. The function of the models is to predict the quality corresponding to the control parameters. The dynamic polynomial neural network (DPNN) was used for data modeling that used the ingot fabrication data.