• Journal of Microbiology and Biotechnology
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• v.7 no.3
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• pp.200-203
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• 1997

Bacteria isolated from ultrapure water made by a high-purity water manufacturing system in a semiconductor manufacturing plant were classified into two groups which either grew in diluted nutrient broth medium (oligotrophic bacteria) or could not grow (copiotrophic bacteria). The nutritional flexibility of oligotrophic and copiotrophic bacteria was investigated. The oligotrophic bacteria were shown to be able to utilize a significantly broader range of organic substrates than the copiotrophic bateria. This finding substantiates the hypothesis that nutritional flexibility is adaptive for oligotrophic bacteria.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.87-92
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• 2019

In this paper, a closed hydroponics device was designed and fabricated to grow and harvest plants in a small space for safe consumption, which enables horticultural activities that are difficult to perform due to space constraints from urbanization. This device also aimed to minimize the air pollution of crops. To obtain data for the optimal growth conditions for crops in this intelligent plant-growing system, sensors were used to measure and control the growth conditions. To investigate the optimal growth conditions, blue lettuce and crown daisy were selected as representative crops. The growth rates were comparatively analyzed through four experiments for each plant. This hydroponics device was used to collect data on growth rates that are altered depending on cultivation conditions, which can then be used to study methods to control the growth rate of crops.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.2
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• pp.249-260
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• 1997

The manufacturing environment is rife with nonlinear processes. In this context, an intelligent production controller should be able to predict the dynamic behavior of various subsystems as they react to transient environmental conditions, the varying internal condition of the manufacturing plant, and the changing demands of the production schedule. This level of adaptive capability may be achieved through a coherent methodology for a learning coordinator to predict nonlinear and stochastic processes. The system is to serve as a real time, online supervisor for routine activities as well as exceptional conditions such as damage, failure, or other anomalies. The complexity inherent in a learning coordinator can be managed by a modular architecture incorporating case based reasoning. In the interest of concreteness, the concepts are presented through a case study involving a knowledge based robotic system.

• Journal of Mechanical Science and Technology
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• v.14 no.4
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• pp.380-392
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• 2000

A typical production-distribution system consist of three main echelons representing the retailer, distributors, and a factory each with an on-site warehouse. The system is sufficiently general and realistic to represent many industrial situations. However, decision functions and parameters have been selected to apply particularly to the production and distribution of consumer durables. The flows included in the model are materials, orders, and those information flows needed to support the material and order-rate decisions. In this work, a realistic production-distribution system has been used as a basic model, which consists of three sectors: retailer, distributor, and factory. That system is a nonlinear 25th-order continuous system interconnected between the echelons. Using a modern control algorithm, a typical multi-echelon production-distribution system using a dynamic controller is numerically simulated in the nominal plant and in the perturbed plant when the piecewise constant manufacturing decision is limited by a factory manufacturing upper-limit due to capital equipment, manpower, and factory lotsize.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.200-211
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• 1997

Most recently, offshore Engineering & Construction field is concerned about integration management technology such as CIM(Computer Integrated Manufacturing), PDM(Product Data Management) and Enterprise Information Engineering in order to cope with the rapid change of engineering and manufacturer specification as per owner's requirement during construction stage of the project. System integration and integrated data modeling with relational database in integration management technology improve the quality of product and reduce the period of the construction project by reason of owing design information jointly. This paper represents the design methodology of system integration using Business Process Reengineering by the case study. The case study is about the offshore plant material information process from front end engineering design to detail engineering for the construction and the basis of monitoring system by integrating and sharing the design information between the 2D intelligent P&ID and 3D plant modeling using relational database. As a result of the integrated data modeling and system integration, it is possible to maintain the consistency of design process in point of view of the material balancing and reduce the design assumption/duration. Near future, this system will be expanded and connected with the MRP(Material Requirement Planing) and the POR (Purchase Order Requisition) system.

• IE interfaces
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• v.21 no.3
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• pp.322-332
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• 2008

Digital Virtual Manufacturing is a technology to facilitate effective product developments and agile productions by digital model representing the physical and logical schema and the behavior of real manufacturing system, and it includes product, resources, processes and plant. For successful applications of this technology, a digital virtual factory as a well-designed and integrated environment is essential. In this research, we constructed a sophisticated digital virtual factory of a Korean automotive company's press shop. For efficient constructions of a digital virtual factory useful to kinematic simulations and visualizations, we analyzed entire business process and detailed activities of press engineering. Also, we evaluated geometries, structures, characteristics and motions of a plant and machines in press shop. The geometric model and related data of a virtual press shop are built and managed by a modeling standard defined in this paper. The virtual manufacturing simulation of press machines is conducted to evaluate kinematic motions, cycle time and locations of components using geometric models and related data. It's for interference checks and productivity improvements. We expect that this virtual press shop helps us to achieve great savings in time and cost in many manufacturing preparation activities in the new car development process of automotive companies.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.530-533
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• 2000

Recently, Manufacturers have recognized the importance of recycling because of the limitation of natural resources and new and proposed laws and legislations that assign responsibility to manufacturer for the ultimate disposal of their products and the environmental problems. In this paper, products assembled recyclable parts and non-recyclable parts are collected after consumer usage and go into a plant. And the collected recyclable parts are disassembled through the disassembly process and have three attributes - re-usable attribute, re-manufacturing attribute and dumping attribute. In this situation, we deal with a production planning for recycle-oriented manufacturing system. The proposed model maximizing the profit in a system is formulated as a mixed-integer linear programming. And then a numerical example is used to evaluate the effectiveness of the proposed model

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.305-307
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• 2021

In this paper, we propose a study related to the development of a Digital-Twin platform using a smart factory based CPPS (Cyber Pysical Production System) using ICT (Information Communication Technology) technology. The platform developed through this study performs a 3D model simulation function in conjunction with P3R (Product, Process, Plant, Resource) including BOP (Bill of Process) management function from the preceding manufacturing process planning stage. In addition, we propose a digital twin platform that can predict production processes, equipment, layout, and production. The platform proposed through this paper proposes a feature that can manage the entire smart factory manufacturing process from the initial planning design stage to the manufacturing, production, operation, and maintenance stages.

• IE interfaces
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• v.16 no.3
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• pp.352-361
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• 2003

Vehicle manufacturing plant is a typical mixed-model production system. Generally it consists of three main shops including body shop, painting shop and assembly shop in addition to engine shop. Each shop contains diverse manufacturing processes, all of which are integrated in a form of flow line. Due to the high pressure from the market requesting small-volume large variety production, production planning becomes very critical for the competitiveness of automotive industry. In order to save costs and production time, production planning system is requested to meet some designated requirements for each shop: to balance the work load in body and assembly shops, and to minimize the number of color changes in painting shop. In this context, we developed a sequencing module for a vehicle production planning system using the ILOG Solver Library. It is designed to take into account all the manufacturing constraints at a time with meeting hard constraints in body shop, minimizing the number of soft constraints violated in assembly shop, and minimizing the number of color changes in painting shop.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.108-118
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• 1997

The heterarchical structure provides a more attractive solution to the conventional hierarchical structure as the density and level of distrubution of computing resources in manufacturing system expands. Tracing the evolution of control structures for automated manufacturing systems, this paper discusses the design principles for heterarchical system to reduce complexity, increase extendability, flexible configurability and suggests a good example of real-time adaptation using the concept of intelligent agent of manufac- turing entities and fault diagmosis system.