• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.28-34
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• 1997

This paper describes an automatic measurement method for the in-line inspection of assembly tolerances of cathod ray electron guns. The method uses an optical microscope with a CCD camera as a probe. An automatic gap recognition algorthm with digital image processing and a new software autofocus algorithm based on using an optimal edge detector have been developed to improve the measuring accuracy. An inspection system has been proposed and practically implemented for in-line inspection to a real factory automation line. The inspection system consists of a gap inspection part and an eyelet. Total time consumed for inspecting all measuring items is about 10 seconds and the repeatability is below .+-. 5 .mu. m

• Korean Journal of Computational Design and Engineering
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• v.14 no.1
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• pp.10-17
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• 2009

Surface detection and parameter estimation in point cloud is a relevant subject in CAD/CAM, reverse engineering, computer vision, coordinate metrology and digital factory. In this paper we present a software for a fully automatic surface detection and parameter estimation in unordered, incomplete and error-contaminated point cloud with a large number of data points. The software consists of three algorithmic modules each for object identification, point segmentation, and model fitting, which work interactively. Our newly developed algorithms for orthogonal distance fitting(ODF) play a fundamental role in each of the three modules. The ODF algorithms estimate the model parameters by minimizing the square sum of the shortest distances between the model feature and the measurement points. We demonstrate the performance of the software on a variety of point clouds generated by laser radar, computer tomography, and stripe-projection method.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.27-30
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• 2019

Factory monitoring systems are gaining importance in wide areas of industry. Especially, there have been many efforts in implementation of vibration measurement and analysis for monitoring the status of rotating machines. In this paper, a digital signal processor (DSP) based monitoring system dedicated to the vibration monitoring and analysis on rotating machines is discussed. Vibration signals are acquired and processed for the continuous monitoring of the machine status. Time domain signals and fast Fourier transform (FFT) are used for vibration analysis. All of the signal processing procedures are done in the DSP to reduce the production and maintenance cost. The developed system could also provide remote and mobile monitoring capabilities to operator via internet connection. This paper describes the overview of the functional blocks of the implemented system. Test results based on signals from small-size single phase motors are discussed for monitoring and defect diagnosis of the machine status.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.271-280
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• 2019

Smart factory, a critical part of digital transformation, enables data-driven decision making using monitoring, analysis and prediction. Predictive maintenance is a key element of smart factory and the need is increasing. The purpose of this study is to analyze the degradation characteristics of a galvanizing kettle for the steel plating process and to predict the remaining useful life(RUL) for predictive maintenance. Correlation analysis, multiple regression, principal component regression were used for analyzing factors of the process. To identify the trend of degradation, a proposed rolling window was used. It was observed the degradation trend was dependent on environmental temperature as well as production factors. It is expected that the proposed method in this study will be an example to identify the trend of degradation of the facility and enable more consistent predictive maintenance.

• The Korean Journal of Archival Studies
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• no.58
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• pp.147-190
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• 2018

Currently, the appraisal system for public records is mainly based on the disposition authority named 'Records Management Criteria Table,' which has many limitations in digital environment. Especially, it does not apply to other systems than the 'Business Management System' and does not adequately reflect the complex environment of records creation. The purpose of this study is to suggest ways to improve the 'Records Management Criteria Table,' so that it can be applied to appraisal of records created in a complex work environment. For this purpose, this study investigates a case of 'Factory Establishment and Registration' activity performed by local governments. For this activity, related laws and regulations, business processes and systems for those processes are analyzed and types of records are examined by each business process and system. Based on these analyses, the development procedure and structure of a new 'Records Management Criteria Table' are suggested, so that it can be applicable as disposition authority in the complex environments of records creation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.4
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• pp.556-561
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• 2022

In this paper, we present a block media communication (BMC) system which employs powerline communication to the equipments used in the welding process for ship-assembly and uses metal block as a communication medium. Inductive couplers are installed on digital feeder and pin jig. Information signal is added to the current generated by the welding gun, and applied to the block. When the welding operation starts, information generated in the field is transmitted to the monitoring server in real-time. The field test on the BMC system confirms that the transmitted data are correctly received at the server. Since the proposed system can be built without any changes to the existing welding process, it is helpful to increase competitiveness of the shipbuilding industry through smart factory of shipyards. It is also possible to quickly respond to emergency situations that may occur to workers in an electromagnetic wave shielding environment or a closed space, the effect of preventing industrial accidents will be great.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.159-166
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• 2018

This paper introduces a manufacturing facility visualization system for the monitoring of smart factories. With the development of technology and the emergence of such terms as the Fourth Industrial Revolution and Industry 4.0, technologies for smart factories are becoming more important. A Manufacturing Execution System that can improve productivity and help decision making by monitoring production plants in real-time is one of the key technologies for smart factories. The application of digital twin technology for more accurate monitoring technology is also an important issue. However, digital twin implementations require an integrated infrastructure that can integrate facility data from multiple manufacturers. Therefore, this paper designs and develops a visualization program that can verify real-time information of facilities using data collection system based on international standard protocol for heterogeneous collection and monitoring of facility data. This allows a factory to consolidate equipment data from multiple manufacturers and to view them in real-time.

• Archives of Reconstructive Microsurgery
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• v.20 no.1
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• pp.38-42
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• 2011

Purpose: To evaluate the effect of intermittent bleeding method in the distal phalanx replantation. Materials and Methods: From January 2007 through June 2009, authors have replanted 117 cases of distal phalangeal amputation in adults at Soo Hospital and Chonbuk National University Hospital. Cases of zone II were 60 cases and zone III 57 according to Allen classification. Male to female ratio was 8.7:1.3. The most common cause was machinery injury in the factory, 98 cases(83.8%), next one was belt injury of the machine, 11 cases(9.4%) and others, 8(6.8%). At least one digital artery and digital nerve were anastomosed under the operating microscope, but vein was impossible to anastomosis as unable to find out in the zone II and III. After anastomosis of one or more digital arteries and nerves, heparine(6,000-10,000 units) was kept to intravenous injection for 24 hours and at the same time fish mouth incision in 2-3 millimeter diameter was made in the distal radial and ulnar margin of the replanted distal phanlanx. From the first 30 minutes to an hour after replantation, incision site was swabbed with heparinized cotton ball for 5 minutes in every 30 to 40 minutes to make sure perfusion for 24 hours, every an hour at the second day, every two hours at the postoperative third to fifth day. Results: 92 cases(78.6%) was completely survived at average postoperative third week follow-up and satisfied with preservation of the finger nail, digit length, good range of motion of the distal interphalangeal joint and acceptable sensibility at average 1.2 years follow-up. Conclusions: Intermittant bleeding method in replantation of crushed distal phalanx impossible to anastomosis of vein at zone II and III of Allen classification was regarded as one of the notable salvage procedure.

• Journal of the Korea Society for Simulation
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• v.32 no.1
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• pp.1-11
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• 2023

Smart factory environments and digital twin environments are established, and today's factories accumulate vast amounts of production data and are managed in real time as visualized results suitable for user convenience. Production simulation techniques are in the spotlight as a way to prevent delays in delivery and predict factory volatility in situations where production schedule planning becomes difficult due to the diversification of production products. With the development of the digital twin environment, new packages are developed and functions of existing packages are updated, making it difficult for users to make decisions on which packages to use to develop simulations. Therefore, in this study, the concept of Discrete Event Simulation (DES) performed based on discrete events is defined, and the characteristics of various simulation packages were compared and analyzed. To this end, studies that solved real problems using discrete event simulation software for 10 years were analyzed, and three types of software used by the majority were identified. In addition, each package was classified by simulation technique, type of industry, subject of simulation, country of use, etc., and analysis results on the characteristics and usage of DES software were provided. The results of this study provide a basis for selection to companies and users who have difficulty in selecting discrete event simulation package in the future, and it is judged that they will be used as basic data.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.4
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• pp.236-244
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• 2024

A representative problem in domestic chestnut industry is the high loss of flesh due to excessive knife peeling in order to increase the peeling rate, resulting in a decrease in production efficiency. In this study, a prediction model for weight loss rate of chestnut by stage of knife peeling process was developed as undergarment study to optimize conditions of the machine. 51 control conditions of the two-stage blade peeler used in the experiment were derived and repeated three times to obtain a total of 153 data. Machine learning(ML) models including artificial neural network (ANN) and random forest (RF) were implemented to predict the weight loss rate by chestnut peel stage (after 1st peeling, 2nd peeling, and after final discharge). The performance of the models were evaluated by calculating the values of coefficient of determination (R), normalized root mean square error (nRMSE), and mean absolute error (MAE). After all peeling stages, RF model have better prediction accuracy with higher R values and low prediction error with lower nRMSE and MAE values, compared to ANN model. The final selected RF prediction model showed excellent performance with insignificant error between the experimental and predicted values. As a result, the proposed model can be useful to set optimum condition of knife peeling for the purpose of minimizing the weight loss of domestic chestnut flesh with maximizing peeling rate.