• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.115-123
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• 2021

A lot of sensor and control signals is generated by an industrial controller and related internet-of-things in discrete manufacturing system. The acquired signals are such records indicating whether several process operations have been correctly conducted or not in the system, therefore they are usually composed of binary numbers. For example, once a certain sensor turns on, the corresponding value is changed from 0 to 1, and it means the process is finished the previous operation and ready to conduct next operation. If an actuator starts to move, the corresponding value is changed from 0 to 1 and it indicates the corresponding operation is been conducting. Because traditional fault detection approaches are generally conducted with analog sensor signals and the signals show stationary during normal operation states, it is not simple to identify whether the manufacturing process works properly via conventional fault detection methods. However, digital control signals collected from a programmable logic controller continuously vary during normal process operation in order to show inherent sequence information which indicates the conducting operation tasks. Therefore, in this research, it is proposed to a recurrent neural network-based fault detection approach for considering sequential patterns in normal states of the manufacturing process. Using the constructed long short-term memory based fault detection, it is possible to predict the next control signals and detect faulty states by compared the predicted and real control signals in real-time. We validated and verified the proposed fault detection methods using digital control signals which are collected from a laser marking process, and the method provide good detection performance only using binary values.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.24-27
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• 2001

Nowadays, increasing demand of the customized products has led to an increased usage of rapid prototyping in the product development. However, the acquisition price of a rapid prototyping equipment is still too high that not every body can afford to buy one. To offer a wide access to the users who need physical prototypes, a connection of the rapid prototyping equipment to the Internet is a viable step. It would allow a large group of customers all over the world to use the manufacturing capability of a service provider offering this kind of manufacturing service. To realize how such an e-manufacturing concept can look like, a LOM-type 3D printer developed at KIST has been used as test site and connected to the Internet. A possible user can log on to the server of the equipment and view his STL file and start the building operation from a remote place. To see whether the operation runs properly, a CCD camera is used to transmit the actual state of operation online. The result so far proves the feasibility of rapid prototyping on the Internet as well as an order-adaptive manufacturing system via web.

• Journal of Power Electronics
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• v.15 no.3
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• pp.849-859
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• 2015

This paper proposes a novel compound-type hybrid energy storage system (HESS) that inherits the unique advantages of both battery/supercapacitor (SC) and the SC/battery HESSs for electric vehicles (EVs). Eight operation modes are designed to match this system. A mode control strategy is developed for this HESS on the basis of these modes, and five classes of operation modes are established to simplify this strategy. The mode control strategy focuses on high operating efficiency and high power output. Furthermore, the compound-type HESS is designed such that the SC is the main priority in braking energy absorption. Thus, this HESS can operate efficiently and extend battery life. Simulation results also show that the compound-type HESS can not only supply adequate power to the motor inverter but can also determine suitable operation modes in corresponding conditions. Experimental results demonstrate that this HESS can extend battery life as well. The overall efficiency of the compound-type HESS is higher than those of the battery/SC and the SC/battery HESSs.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.63-73
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• 2001

This paper presents a process and operation planning system with an NC code post-processor for effective machining of press dies for production of cars. Based on the machining features, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor we developed adjusts feedrates along the tool path to reduce machining time. The adjustment rule is selected based on the metal removal rate estimated by virtually machining with virtual cutting tool.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.287-297
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• 1997

This research is concerned with operation control problem for an automated manufacturing system which consists of two machine centers and a single automatic guided vehicle. The objective is to develop and evaluate heuristic scheduling procedures that minimize maximum completion time to be included travel time of AGV. A new heuristic algorithm is proposed and a numerical example illustrates the proposed algorithm. The heuristic algorithm is implemented for various cases by SLAM II. The results show that the proposed algorithm provides better solutions than the previous algorithms.

• 연구논문집
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• s.26
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• pp.57-68
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• 1996

Recently, a lot of researches on material handling system are actively studied for realization of FA(Factory Automation), FMS(Flexible Manufacturing System) and CIM(Computer Integrated Manufacturing). Management and application of material handling system are precondition technologies playing an important part in integration of production system including manufacturing. assemhly, and inspection cell. In this paper, the general situation of automation technology is investigated and technology level is analyzed in comparision with an advanced country. And the operation trend and part of material handling system including AS/RS, AGV, and Conveyor, are studied. And also technologies related to material handling system in the inside and outside of the country are studied.

• IE interfaces
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• v.21 no.4
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• pp.435-443
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• 2008

RFID (Radio Frequence Identification) is emerging technology and it is used for many fields. The research about RFID has been focused on hardware such as increasing hitting ratio. But recently the research about how and where RFID can apply is going on. Especially people are doing research about connecting RFID with existing information system. In this paper, when BPM manage RFID based manufacturing operation process, we show components which is needed and how we can obtain the components. And we apply this to straw manufacturing process on experiment. The claim-handling process and order-handling process which need improvement in straw manufacturing are chosen and we improve those processes. For executing the improved process, we define components which are database, data acquisition workflow and real-time event processing system and then we make prototype system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1303-1310
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• 1999

In this paper, the Timed Petri-Nets(TPN) modeling of Modular Cell Manufacturing Systems(MCMS) was investigated to overcome the limit of batch mode operation, which has been one of the most popular manufacturing types to produce an extensive industrial output and to be able to adopt to suitable and quickly changing manufacturing environments. A model of the MCMS was developed in reference to the actual TFT-LCD manufacturing system. TFT-LCD manufacturing system is not mass-productive in batch mode, but it operates in the form of MCMS which consists of a sequence of several cells with four processes of operation, including those of color filter(C/F), TFT, cell, and module. The cell process is further regrouped in those of Front-End and Back-End. For the Back-End cell process, it is reconstructed into a virtual model, consisting of three cells. The TPN modeling encompasses those properties, such as states and operations of machines, the number of buffers, and the processing time. The performance of the modeling was further examined in terms of scheduling system. The productivity in each cells was examined with respect to the change of failure rate of the cell machines and Automatic Guided Vehicles(AGV) using simulation by TPN.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.122-122
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• 2000

Polishing work of a free-curved surface die demands simple and repetitive operations but requires a considerable amount of time for high precision. In out previous study, to reduce the polishing time and solve the problem of the shortage of skilled workers, the automatic polishing system was developed. However, in the polishing process of die, workers have to stay still in factory to monitor the polishing process for a long time in the poor environment. Therefore, this study proposes the remote operation and monitoring system of the automatic polishing robot. The developing system offer worker monitoring functions and teleoperating functions, as following: system state check, manual manipulation mode, automatic mode, manual teaching mode, automatic teaching mode, simulation by virtual manufacturing device. And automatic teaching system is developed to easily obtain a teaching data.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.76-83
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• 2019

The South Korean government is actively assisting the supply of the smart factory solutions to SMEs (Small & Medium-sized Enterprises) according to its manufacturing innovation 3.0 policy for the smart manufacturing as the 4th industrial revolution era unfolds. This study analyzed the impacts of the smart factory solutions, which have been supplied by the government, on the companies performances. The effects of the level of smart factory and the operation capabilities for the smart factory solutions on company performances, and the mediating effects of manufacturing capabilities have been analyzed using SPSS and AMOS. The data for this survey-based study were collected from the SMEs which implemented the smart factory solutions since 2015. The results show that the level of smart factory solutions adopted and operation capabilities for the smart factories do not have direct effects on the company performances, but their mediating effects on the manufacturing capabilities matter and the manufacturing capabilities effect directly on the company performances. In addition significant factors boosting the operation capability for the smart factory and the levels of the smart factory solutions are identified. Finally, the policy direction for enhancing the smart factory effects is presented, and the future research directions along with the limitations are suggested.