• Proceedings of the Korea Society for Simulation Conference
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• 1996.05a
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• pp.15-15
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• 1996

A shop floor control system (SFCS) is the central part of a CIM system used to control the activities of several pieces of manufacturing equipment (e.g., NC machines, robots, conveyors, AGVs, AS/RS). The SFCS receives orders and related process plans, and then performs selecting a specific process routing, allocating resources, scheduling the workpieces, downloading the processing instructions (e.g., RS-274 instructions for NC machines, VAL II programs for robot), monitoring the progress of activities, detecting and recovering from errors, and preparing reports on the status of the manufacturing system. Simulation has been utilized in discovering control policies used for resolving shop floor be control problems such as resource contentions, part dispatching, deadlock. The simulation model must be designed to respond to real-time data coming from a shop floor. However, to rapidly build a realtime simulation model of SFCS cannot be easily accomplished. This talk is to address an automatic program generator of discrete event simulation model for shop floor control from process plans and resource models. The program generator is capable of constructing complete discrete simulation models for multi-product and multi-stage flexible manufacturing systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.135-138
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• 2000

This paper is intended to propose what manufacturing configuration (manufacturing planning and shop floor control) is suitable for the tire industry. Basically tire-manufacturing process is mixed-products, parallel-disconnected-flow-shop. Both throughput time and cycle tine are very short, the variety of tires is very high, the setup time is long, shop floor data reporting requirements is high, and there are many equipments and people working. And with no exception, tire industry also now confronts increasing requirements of delivery conformance with the above peculiar characteristics of tire manufacturing and changing market environments, this paper suggests, weekly master scheduling with no MRP is desirable and traditional kanban is right selection for shop floor control/scheduling. This paper describes why this configuration should be, using the manufacturing engineering principles and some new insights like four primitives of parallel flow shop. Generally known that shop with high parallel-product-mix and long setup time isn't good candidate for kanban. The four primitives of parallel flow shop explain why kanban is also useful scheduling technique in that environment.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.4
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• pp.719-739
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• 1996

A common control model used to implement computer integrated manufacturing(CIM) is based on the hierarchical decomposition of the shop floor activities, in which supervisory controllers are responsible for all the interactions among subordinates. Although the hierarchical control philosophy provides for easy understanding of complex systems, an emerging manufacturing paradigm, agile manufacturing, requires a new control structure necessary to accommodate the rapid development of a shop floor controller. This is what is called autonomous agent-based heterarchical control. As computing resources and communication network on the shop floor become increasingly intelligent and powerful, the new control architecture is about to come true in a modern CIM system. In this paper, heterarchical control is adopted and investigated, in which a controller for a unit of device performs three main functions - planning, scheduling and execution. Attention is paid to the planning function and all the detailed planning activities for heterarchical shop floor control are identified. Interactions with other functions are also addressed. In general, planning determines tasks to be scheduled in the future. In other words, planning analyzes process plans and transforms process plans into detailed plans adequate for shop floor control. Planning is also responsible for updating a process plan and identifying/resolving replanning activities whether they come from scheduling or execution.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.185-192
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• 1995

A common control model used to implement computer integrated manufacturing(CIM) is based on the hierarchical decomposition of the shop floor activities, in which supervisory controllers are responsible for all the interactions among subordinates. Although the hierarchical control philosophy provides for easy understanding of complex systems, an emerging manufacturing paradigm, agile manufacturing, requires a new control structure necessary to accommodate the rapid development of a shop floor controller. This is what is called CSCW(computer supported cooperative work)-based control or component-based heterarchical control. As computing resources and communication network on the shop floor become increasingly intelligent and powerful, the new control architecture is about to come true in a modern CIM system. In this paper, CSCW-based control is adopted and investigated, in which a controller for a unit of device performs 3 main functions - planning, scheduling and execution. In this paper, attention is paid to a planning function and all the detailed planning activities for CSCW-based shop floor control are identified. Interactions with other functions are also addressed. Generally speaking, planning determines tasks to be scheduled in the future. In other words, planning analyzes process plans and transforms process plans into detailed plans adequate for shop floor control. Planning is also responsible for updating the process plan and identifying/resolving replanning activities whether they come from scheduling or execution.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.176-181
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• 2001

Due to the increasing complexity to handle conflicts and interruptions caused by resource failures and rush orders, shop control is obliged to redesign its organization according to the changing demands of the manufacturing control. These demands are leading to the development of decentralization and gradually to their permanent optimization. As a result, a powerful modeling method which can be adapted efficiently is required. The use of agent theory enables specific modeling of the relevant shop planning activities. The planning activities are modeled in a so-called activity modeling through the definition of three classes of agents; Plan Agent, Manufacturing System Agent and Control Agent as well as the description of the cooperative relationship among these agents. On the basis of the activity model the agent-based shop control method is developed which emphasizes the distributed problem-solving and the cooperation with relevant agents.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.65-72
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• 2014

To improve the productivity of manufacturing company, the analysis of loss in shop floor has to be conducted and validated. This paper introduces the downtime tracking module using the pre-developed shop floor information acquisition system. To collect the downtime, it utilized shop floor monitoring information, user-registered downtime event, equipment diagnosis algorithm and operator's input. Also, it provided the user interface for the analysis of downtime. From the results of a pilot study, the usability of developed system was validated.

• IE interfaces
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• v.8 no.3
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• pp.187-195
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• 1995

본 연구는 생산 현장과 기술 설계 부서를 효율적으로 연결시키고 기술 자료를 공유화하기 위해서는 각 역할분담(Software Module)에서 공통DB(EDB/MDB)를 공유화할 뿐만 아니라, 이러한 공통DB를 특별한 지식이 없이 이용할 수 있는 공통 API)(Application Program Interface)와 DB를 통합적으로 관리해주는 Servet Process의 필요성의 업계의 동향과 국제 표준화 동향을 참고하여 설명하고자 한다.

• Korean Journal of Computational Design and Engineering
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• v.4 no.4
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• pp.339-349
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• 1999

The punose of this paper is to introduce the comprehensive CAM system (called PosCAM) supporting various function requested from shop floor operators. PosCAM is comported of two subsystems (PosCAM I and PosCAM II) which are designed to make up for the contemporary CAD/CAM systems. PosCAM I is mainly for : a) verifying the part programs written in both custom macros and standard G-codes, b) enhancing machining productivity and quality with built-in cutting conditions and feedrate optimization algorithm. PosCAM II is for : a) efficiently managing the numerous part programs and tool data stored in CNC memory, and b) integratively controlling and monitoring various CNCs from the control center through RS-422 with DNC 2 protocol. The developed systems have been tested via various experiments, and can be Applied for the industrial CNC machine shop as a means for enhancing productivity. The PosCAM system has been implemented and successfully used in the Machine Shop Department of PosCAM since march 1998.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.380-385
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• 1993

The demand for automatic manufacturing systems is incerasing. Computer Integrated Manufacturing(CIM) technology is believed to be a solution for the problem to enhance productivities and flexibilities. Although researches on CIM have been conducted treendously, application of the technology is not widely accepted yet. The CIM research on the shop floor starts with the Flexible Manufacturing System(FMS). One of the crucial obstacles to the FMS is the lack of excellent strategies for efficient operations. The aim of this research is constructing an automation scheme in the low level of factories where various machinaries are involved. An operating strategy is established for an automation unit named as a cell which resides between the upper level computers and manufacturing shop floor. The cell is defined to fit into the total manufacturing system. The defined cell has more functions than conventional cells. A scheduling scheme is adopted for the shop floor operations. A set of software has been developed and tested through simulations and shop floor experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.8
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• pp.760-767
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• 2011

The flexibility and evolvability are critical characteristics of modern manufacturing to adapt to changes from products and disturbances in the shop floor. The technologies inspired from biology and nature enable to equip the manufacturing systems with these characteristics. This paper proposes an ant colony inspired autonomous manufacturing system in which the resources on the shop floor are considered as the autonomous entities. Each entity overcomes the disturbance by itself or negotiates with the others. The swarm of cognitive agents with the ant-like pheromone based negotiation mechanism is proposed for controlling the shop floor. The functionality of the developed system is proven on the test bed.