• Journal of Korea Society of Industrial Information Systems
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• v.15 no.4
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• pp.61-70
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• 2010

In this paper, we propose a mobile document viewer which is executable on a variety of mobile platforms. The proposed viewer is designed with file decoding engine and independent module which are adopted with os independent. The proposed viewer can be used as a basis of document editing tool by analyzing the characteristics of the document file.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.648-652
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• 2008

We all know *.x file is a bridge of the 3D model developer and the game developer. In today's 3D game programming, more and more advanced hardware support it to run, but we still need to consider the methods to generate the animations. 3D model maker is tired of rectifying the skeletal animations. If he mistakes one point in some one animation, this will lead to distortion in *.x file. Then the modification consumes long time. So finding a good blending method is the best choice for generating multiple skeletal animations. There were some methods for animations blending. In this paper, we could use 3D max or Maya to blend animations; and we could use *.x file and blend animations in coding. And we will use 3D max 8.0 to export the *.x file and present a better way to combine skeletal animations.

• Imaging Science in Dentistry
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• v.34 no.3
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• pp.145-150
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• 2004

Purpose: To compare three digital radiographic imaging sensors by evaluating the visibility of endodontic file tips with interobserver reproducibility and assessing subjectively the clarity of images in comparison with the x-ray film images. Materials and Methods: Forty-five extracted sound premolars were used for this study. Fifteen plaster blocks were made with three premolars each and #8, 10, 15 K-flexofiles were inserted into the root canal of premolars. They were radiographically exposed using periapical x-ray films (Kodak Insight Dental film, Eastmann Kodak company, Rochester, USA), Digora imaging plates (Soredex-Orion Co., Helsinki, Finland), CDX 2000HQ sensors (Biomedisys Co., Seoul, Korea), and CDR sensors (Schick Inc., Long Island, USA). The visibility of endodontic files was evaluated with interobserver reproducibility, which was calculated as the standard deviations of X, Y coordinates of endodontic file tips measured on digital images by three oral and maxillofacial radiologists. The clarity of images was assessed subjectively using 3 grades, i.e. plus, equal, and minus in comparison with the conventional x-ray film images. Results: Interobserver reproducibility of endodontic file tips was the highest in CDR sensor (p < 0.05) only except at Y coordinates of #15 file. In the subjective assessment of the image clarity, the plus grade was the most frequent in CDR sensor at all size of endodontic file (p < 0.05). Conclusion : CDR sensor was the most superior to the other sensors, CDX 2000HQ sensor and Digora imaging plate in the evaluation of interobserver reproducibility of endodontic file tip and subjective assessment of image clarity.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.1-6
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• 2013

A LEO satellite transmits recorded images to a ground station using an X-band antenna during contact. The X-band antenna points to the ground station according to a TPF (tracking parameter file) during communication time. A TPF generation software generates azimuth and elevation profile which make the antenna point to the ground station using satellite orbit and attitude information and mission information including recording and downlink operation. When the satellite passes above the ground station, azimuth velocity increases rapidly so that jitter may occur if the azimuth velocity is in specific range. In case of realtime mission in which the satellite perform recording and downlink simultaneously, azimuth velocity must be lower than specific value to prevent image blur due to jitter effect. The method to point one virtual ground station has limitation of azimuth velocity reduction. In this paper, we propose the azimuth fixing method to reduce azimuth velocity of X-band antenna. The experimental results show that azimuth velocity of the X-band antenna is remarkably reduced using proposed method.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.39-46
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• 2013

If a file system is damaged because of the unusual system close, the system performs the consistency test using fsch and it takes long time. Especially, if it is a big file system, it will take a lot of time. The journaling file system that uses journaling technique, can reduce the restoring time because it uses meta data and it may increase the chance of restoration when restoring. The goal of this paper compared performance evaluation journaling file systems focused on the reading and writing using Iozone tool which is the kernel based benchmarking tool in linux operating system. In this paper, Ex4 which is the current basic Linux file system. is 1.28x faster than XFS file system in terms of file read performance and 1.22x faster than Ext3 file system in terms of file write performance.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.758-767
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• 1995

The purpose of this study was to evaluate canal shaping ability after canal preparation by using engine-driven nickel-titanium file and endosonic file in curved canals. 30 mesiobuccal canals of molars extracted within recent 3 months were divided into 3 groups. Group I and group II were prepared by using engine-driven nickel-titanium Gates-Glidden drill type and the engine-driven nickel-titanium file type. Group III prepared by using en do sonic file. The image of preinstrumented canals was taken by X-ray. The image of postinstrumented canal was taken by X-ray in the same condition of preinstrumentation. A magnified X-ray image on magnifier screen was traced and then compared the preinstrumentated canal image with the postinstrumentated canal image by superimposing method. The following results were obtained : 1. In the change of canal curvature, the engine-driven nickel-titanium Gates-Glidden drill type showed the least change and the ultrasonically filing showed the greatest change. 2. In the percentage of canal enlargement, the engine-driven nickel-titanium file type was greatest at all level(p<0.05), the apex of all group was the greatest, the difference of ultrasonically filing group showed greater between apex and cervix. 3. The percentage of canal enlargement on convex side was greater than that of on concave side in apex of each group(p<0.05). In the ultrasonically filing group, both sides of canal enlargement showed sharply difference(p<0.01). 4. The percentage of canal enlargement on convex side was greater than that of on concave side in the third of cervix of the engine-driven nickel-titanium file type and the ultrasonically filling. The percentage of canal enlargement of convex and concave side in the third of middle of the engine-driven nickel-titanium Gates-Glidden drill type show a similar canal enlargement between convex side and concave side. As above result, the engine-driven nickel-titanium file type was greater in canal enlargement than the other instruments. The engine-driven nickel-titanium Gates-Glidden dirll type was efficient endodontic instrument for curved canal preparation because it was least change in canal curvature.

• The Journal of the Korean dental association
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• v.45 no.6 s.457
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• pp.362-369
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• 2007

The aim of this study was to investigate the effect of the hybrid instrumentation method with ProTaper and ProFile on the change of root canal area and distance from the canal to the root surface after canal shaping. The mesial canals of twenty extracted mandibular first molars having $10-20^{\circ}\Delta$ curvature were scanned using X-ray microcomputed tomography (XMCT)-scanner before root canals were instrumented. They were divided into four groups (n=10 canals ter group). In Group 1, root canals were instrumented by the step-back technique with stainless steel K-Flexofile after coronal flaring. The remainders were instrumented by the crown-down technique with, ProTaper system (Group 2), ProFile (Group 3) or ProTaper (Group 4). All canals were prepared up to size 25 at the end-point of preparation and scanned again. Pre- and post-operative cross-sectional images of 1, 3, 5, and 7 mm from the apical foramen were compared. For each level, change of cross-sectional canal are and distance to the nearest external root surface was calculated using Adobe Photoshop 6.0 and image software program. In the change of cross-sectional area, Group 4 was less than Group 2 at 3 mm and 5 mm level (p<0.05). In the difference of the distance from the canal to the root surface after canal shaping, Group 4 was least among the other groups at 7 mm level (p<0.05). According to the results, the methods using ProFile or K file only and the hybrid instrumentation technique using ProTaper and ProFile are more appropriate methods of canal preparation than ProTaper system for narrow of curved canals.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1016-1020
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• 2000

In this study, a structural characteristics analysis system for motor-integrated high-speed spindle systems, “SpindleX”, is developed based on the Timoshenko theory and the multi-layered finite element method. Since “SpindleX” has the various analysis modules related to static deflection analysis, modal analysis, frequency response analysis, unbalance response analysis and so on, it is useful in performing systematically and quantitatively the design and evaluation processes of spindle system under the windows GUI environment. Also, to enhance the user-friendliness, “SpindleX” possesses the various additional functions such as the DXF file interface for auto-importing the shape and geometric data of spindle system from the DXF file, the bearing database for auto-importing the mechanical properties and geometric data of bearing by the bearing number, and the graphical visualization for certificating the imported and analysed data of spindle system.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.51.1-51.10
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• 2020

Objectives: No studies have yet assessed vibration characteristics according to endodontic file length. Accordingly, the objective of the present study was to examine the vibration characteristics according to nickel-titanium file length and to compare these characteristics between different file systems. Materials and Methods: A total of 45 root canal models were divided into 3 experimental groups (n = 15 each) based on the file system used (ProTaper Gold [PTG], ProTaper Next, or WaveOne Gold [WOG]). Each experimental group was further divided into 3 subgroups according to file length (21, 25, or 31 mm). An electric motor (X-SMART PLUS) was used in the experiment. For each file system, vibrations generated when using a size 25 file were measured and used to calculate the average vibration acceleration. The differences in vibrations were analyzed using 1-way analysis of variance and the Scheffé post hoc test with a confidence interval of 95%. Results: In the PTG file system, significantly lower vibration acceleration was observed when using a 21-mm file than when using a 31-mm file. In the WOG file system, significantly stronger vibration acceleration was observed when using a 31-mm file than when using 21- or 25-mm files. Regardless of the file length, the WOG group exhibited significantly stronger vibration acceleration than the other 2 experimental groups. Conclusions: In clinical practice, choosing a file with the shortest length possible could help reduce vibrations. Additionally, consideration should be given to vibrations that could be generated when using WOG files with reciprocating motion.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.18-25
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• 1996

In this study, we have developed the stereolithography system that supports the development of a products. This paper presents the development of the stereolithography system. The system is composed of hardware, software and control part. The software converts a STL file to NC data and displays the monitoring figure in control part. The hardware part deals with structure of machine. The most important theme in this paper is LG-SLCAM software. This software can generate NC data and scanning condition data from a STL file semiautimatically. On the basis of three diensional shapes, it makes data for support structure from STL file. The effectiveness of using out stereolithography system is confirmed by processes of good development.