• Journal of Technologic Dentistry
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• v.43 no.2
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• pp.48-55
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• 2021

Purpose: This study aimed to analyze deformation according to post-curing of complete arch artificial teeth for temporary dentures printed with a digital light processing (DLP) printer. Methods: An edentulous model was prepared and an occlusal rim was produced. The edentulous model and occlusal rim were scanned using a model scanner. A complete denture was designed using a dental computer-aided design, and the denture base and artificial tooth were separated. Ten complete arch artificial teeth were printed using a 3D printer (DLP). Complete arch artificial teeth was classified into the following three groups: a group no post-curing (NC), a group with 10 minutes post-curing (10M), and a group with 20 minutes post-curing (20M). Specimens were scanned using a model scanner. The scanned data were overlapped with the reference data. Statistical analysis was performed using one-way ANOVA analysis of variance, Kruskal-Wallis test, and Mann-Whitney U test (α=0.05). Results: Regarding the overall deviation of complete arch artificial teeth, the NC group showed the lowest mean deviation of 111.13 ㎛ and the 20M group showed the highest mean deviation of 131.03 ㎛. There were statistically significant differences among the three groups (p<0.05). Conclusion: The complete arch artificial tooth showed deformation due to post-curing. In addition, the largest shrinkage deformation was observed at 10 minutes of post-curing, whereas the least deformation was observed at 20 minutes.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.48-56
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• 2022

The importance of data analysis in baseball has been increasing after the success of MLB's Oakland which applied Billy Beane's money ball theory, and the 2020 KBO winner NC Dinos. Various studies using data in baseball has been conducted not only in the United States but also in Korea, In particular, the models using deep learning and machine learning has been suggested. However, in the previous studies using deep learning and machine learning, the focus is only on predicting the win or loss of the game, and there is a limitation in that it is difficult to interpret the results of which factors have an important influence on the game. In this paper, to investigate which factors is important by position, the prediction model for the Golden Glove award which is given for the best player by position is developed. To develop the prediction model, XGBoost which is one of boosting method is used, which also provide the feature importance which can be used to interpret the factors for prediction results. From the analysis, the important factors by position are identified.

• Knowledge Management Research
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• v.21 no.3
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• pp.27-44
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• 2020

In order to solve the user's information overload problem, recommender systems infer users' preferences and suggest items that match them. The collaborative filtering (CF), the most successful recommendation algorithm, has been improving performance until recently and applied to various business domains. Visual information, such as book covers, could influence consumers' purchase decision making. However, CF-based recommender systems have rarely considered for visual information. In this study, we propose VizNCS, a CF-based deep learning model that uses visual information as additional information. VizNCS consists of two phases. In the first phase, we build convolutional neural networks (CNN) to extract visual features from image data. In the second phase, we supply the visual features to the NCF model that is known to easy to extend to other information among the deep learning-based recommendation systems. As the results of the performance comparison experiments, VizNCS showed higher performance than the vanilla NCF. We also conducted an additional experiment to see if the visual information affects differently depending on the product category. The result enables us to identify which categories were affected and which were not. We expect VizNCS to improve the recommender system performance and expand the recommender system's data source to visual information.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.122-124
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• 2022

Handling Passenger Traffic is the main challenge for designing an elevator group-control algorithm. Advanced control systems such as Hyundai's Destination Selection System(DSS) lets passengers select the destination by pressing on a selecting screen, and the systems have shown great efficiency. However, the algorithm cannot be applied to the general elevator control system due to the expensive cost of the technology. Often many elevator systems use Nearest Car(NC) algorithms based on the SCAN algorithm, which results in time efficiency problems. In this paper, we designed an elevator group-control algorithm for specific buildings that have approximate timetable data for most of the passengers in the building. In that way, it is possible to predict the destination and the location of passenger calls. The algorithm consists of two parts; the waiting function and the assignment function. They evaluate elevators' actions with respect to the calls and the overall situation. 10 different timetables are created in reference to a real timetable following midday traffic and interfloor traffic. The specific coefficients in the function are set by going through the genetic algorithm process that represents the best algorithm. As result, the average waiting time has shortened by a noticeable amount and the efficiency was close to the known DSS result. Finally, we analyzed the algorithm by evaluating the meaning of each coefficient result from the genetic algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.416-421
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• 2002

The purpose of t his paper is to database each factors from experimental results and develop the servo-controlled feeding system on these database. At first, spring back and bending farce are analyzed by basic theory of bending processing. In database, through practical experiment by the expert various types of bending angel and thickness of plate are tested and classified with SB34P and Aluminum. For the development of servo-controlled feeding system, automatic feeding system is designed and manufactured with ball screw and LM guide and performance of the developed feeding system is tested under condition of standard machine tool examination. Also, Mechanical consideration of mainframe in press brake, development of controller based on NC, program for servo-control are studied. Finally, based on experimental data, the system is operated and compared with theoretical data

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.160-165
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• 2002

A study on digital processes of injection mold in reverse engineering are presented. Reverse engineering is useful fur several cases, where user has no geometry information of object. Laser scanner is used to obtaining 3D coordinates of object. Sequences to process cloud data are described; sampling to reduce number of points, sorting to adjust the point order, and fitting to curve and surface, and so on. Split slide structure of mold is used fur undercut part and high viscosity material. Flow of injection molding are analysed to correct cooling channel and simulate molding conditions. NC tool paths are generated to carve core and cavity. The processes are performed in digital data for reduction of lead time and consecutive geometry data.

• IE interfaces
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• v.9 no.2
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• pp.119-128
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• 1996

A procedure is presented for a 3D-contour machining without cutter interferences. The 3D-contouring machining along a spatial curve is often required for manufacturing trimming and flange dies in motor industries. Input data for the machining contour is a spline curve with polynomial vector equation provided by CATIA system. Points are sampled on the contour curve and line segments and helical curves are approximated from the point data. Cutter interference is checked on the approximated spline and all of interference curves are substituted with interference-free helical curves for a tool path generation. The non-machined curve areas are locally machined by tools with smaller diameters. A tool radius offset is considered for generating NC data to be free with tool size.

• Journal of Mechanical Science and Technology
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• v.14 no.6
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• pp.675-689
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• 2000

Rapid design and production techniques are indispensable for the custom-made production systems. For manufacturing custom-made shoes, the shoelast should be designed rapidly from the individual foot model. In this paper, we develop an integrated system for rapid design and manufacturing of custom-tailored shoes. The foot shape measurement sub-system allows scanning a standard shoelast and an individual foot and then extracts the three-dimensional crosssectional data of the shoelast and the human foot shape from the captured image data. The shoelast design sub-system uses the scanned data to design new customized shoelast curves or surfaces with the heeling and mixing algorithms built in this system. The pattern design subsystem provides a method, which transforms a shoe-upper surface designed by a stylist into a flat-pattern that can be manufactured. We also export the surface model to an NC machine to manufacture the physical shoelast model.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.48-53
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• 1993

At present, the manufacturing industry is in a process of a great change. There is a demand for a variety of types and shorter product life. The change increases the number of different tools and frequencies of tool changes. For the most part, the tools are presetted and offset values are entered manually or via punched tapes to NC machines. Thus a large amount of capital is tied up in the tool area and considerable productive time is lost. Consequently, there is a need for improvement in tool management. This paper describes a computer controlled tool data management system which include: 1) tool identification with bar code. 2) computer aided management and updating of tool data. 3) tool data communication with tool presetter, CNC, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.396-399
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• 1995

In this study, Acquisition system is proposed to acquire 3 dimensional data of the free surface model using direct pulse control to machining center. Todo this, I/F to connect between manual operating handle and computer is made, and 3 dimensional shape measuring algorithm using Z-map is applied. The 3 dimensional shape data of the free surface model measured by laser displacement sensor and electric touch probe are achieved directly. Performance of the proposed system is evaluated through measurement of various shape model.