• Journal of the Korea Computer Graphics Society
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• v.20 no.2
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• pp.13-24
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• 2014

In this study, a graphics-processing-unit (GPU)-based acceleration technique is proposed for the feature-based image morphing. This technique uses the depth-buffer of the graphics hardware to calculate efficiently the shortest distance between a pixel and the control lines. The pairs of control lines between the source image and the destination image are determined by user's input, and the distance function of each control line is rendered using two rectangles and two cones. The distance between each pixel and its nearest control line is stored in the depth buffer through the graphics pipeline, and this is used to conduct the morphing operation efficiently. The pixel-unit morphing operation is parallelized using the compute unified device architecture (CUDA) to reduce the morphing time. We demonstrate the efficiency of the proposed technique using several experimental results.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.51-59
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• 2002

The aim of the present study was to investigate the distribution of periodontally hopeless teeth in patients who had not been treated. Five hundred nineteen teeth of 163 patients who had visited at the Department of Periodontology, Chonbuk National University Hospital during the period from January 1999 to July 2001 were selected as a periodontally hopeless tooth. Selection criteria were as follows: 1) probing pocket depth more than 8mm, 2) tooth mobility of degree III, 3) radiographic bone loss more than 75%. The contralateral tooth to a hopeless tooth (experimental tooth) was designated as a control tooth. Between the experimental and control tooth, differences in probing pocket depth, tooth mobility and amount of radiographic bone loss were examined as well as correlation. The results showed that hopeless teeth were most frequently found in the maxillary first molar position and least frequently in the maxillary canine position. Differences between experimental and control teeth were 2mm in probing depth, 1 degree in tooth mobility, and 20% in amount of bone loss (p<0.01). The periodontal conditions between the experimental and control teeth showed correlation in general, however, statistical significances were found in posterior teeth positions. Within limitations of this study, it can be concluded that local factors may play a role in deterioration of periodontal disease along with symmetrical character of periodontal disease.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.527-532
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• 2013

Depth estimation is an essential factor for robot vision, 3D scene modeling, and motion control. The depth estimation method is based on focusing values calculated in a series of images by a single camera at different distance between lens and object. In this paper, we proposed a relative depth estimation method using focus measure. The proposed method is implemented by focus value calculated for each image obtained at different lens position and then depth is finally estimated by considering relative distance of two patterns. We performed various experiments on the effective focus measures for depth estimation by using various patterns and their usefulness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.101-102
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• 2011

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1352-1355
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surface. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamometer. Based on the parameter estimation of cutting dynamics and the admittance model-based nanodynamic control scheme, simulation results are shown.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.23-32
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• 2009

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.503-512
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• 1994

The purpose of this study was to assess the clinical and microbiological effect of chlorhexidine rinse following scaling and root planing on periodontits. 10 patients with periodontal disease were selected for the study. They had not taken antibiotics for months and no history of dental treatment for 6 months before the study. They were good in general health. Patients received a scaling and root planing under local infiltration anesthesia, chlorhexidine rise group were subjected to twice a day 0.1% chlorhexidine rinse for a period 2 week. After initial clinical(plaque index, gingival index, probing pocket depth), microbiological and BANA tests were determined, each subject received a single session of scaling and root planing but no oral hygiene instructions. Clinical indices were measured, microbial parameters and BANA test were reassessed 1, 2 and 4 weeks after treatment. The results were as follows : 1. Plaque index, gingival index and pocket depth in chlorhexidine rinse group and control group were not significantly reduce during all weeks when compared chlorhexidine rinse group with control groups. Plaque index in chlorhexidine rinse group and control group were siginificantly reduced at 1, 2, 4weeks(P<0.05), gingival index and pocket depth wee ignificantly reduced at 2, 4weeks in both groups(P<0.05). 2. Perecntage of cocci and motile rods was significantly changed at 1, 2, 4weeks in chlorhexidine rinse group(P<0.05), control group was significantly changed at 4weeks in control group(P<0.05), intergroup difference was significantly at 2weeks in cocci and 4weeks in motile rods(P<0.05). 3. Percentage of non-motile rods in all group were not significantly changed when compared with those of baseline. 4. Percentage of spirochetes was significantly reduced at 4 week(P<0.05), control group was not significantly reduced during all weeks. 5. BANA test scores was significantly reduced during all weeks in chlorhexidine rinse group(P<0.05), control group was not significantly reduced during all weeks. The result showed that clinical and microbiological effect following scaling, root palning and chlorhexidine on periodontal disease.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.847-852
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• 2003

The purpose of this paper is to develop the new deep mixing method installed automatic control equipments for the better construction in deep mixing and grouting. Civil, geotechnical, electronic, and communication experts have worked together for a long time for the development of automatic measuring devices using wire and wireless transmitting-receiving set. A series of laboratory and field experiments were carried out to check the reliability and field applicability of this system. New total automatic control system including automatic devices for checking angle, depth and quantity of injected grout was invented from the result of this research.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.81-87
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• 2000

A variable cutting speed control model was developed to be implemented for the flexible disk grinding process Control algorithm was based on the error referred by the discrepancy between current disk angle and intended one that are pro-posed to produce desired resulting depth of cut. Controller was implemented in two different aspect One was to initiate the control law from the beginning while the other was to activate as soon as the disk start to produce ground surface i.e. The beginning of the between edges stage. Several performance analysis were conducted comparing various process parameters such as cutting force disk angle depth of cut and disk speed with respect to process transition time Tentative results revealed that controller implemented from the earlier stages of the process showed better performance than the other revealed that controller implemented from the earlier stages of the process showed better performance that the other.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.221-224
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• 1996

Since impact phenomenon is highly nonlinear, the analysis and control of the contact motion has been a challenging subject. Various researches have been carried out mostly for the contact of a rigid robotic manipulator with a stiff and elastic environment. This paper is motivated by a new contact task: the in-circuit test of a printed circuit board. In this process, high speed contact occurs between a rigid probing manipulator and a plastically deformable work environment. A new dynamic model of the impact controlled probing task has been proposed, considering contact with the plastically deformable object. Approaching velocity conditions to avoid an excess of the allowable penetration depth and control the generated impact force properly are derived from the proposed model. The results of the simulation studies are made for various probing conditions and show the validity of the proposed model.