• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.82-88
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• 1996

A simpel formular is proposed for the analysis of gate delay of CMOS gate in the low V$_{GS}-V_{TH}$ scaling. The effects of magnitude of V$_{GS}-V_{TH}$ on gate delay can be readily found through the formula so that it can be used ot design the device parameters in the low V$_{DD}$ CMOS circuits. The measured sresutls confirm the usability of the proposed formula and quantifies the improtance of V$_{TH}$ effects on gate delay under low voltae operation. Applying the formula to the prototype NMOSFET devices representing the five generations of technology, the impacts of the V$_{GS}-V_{TH}$ on the various aspects of the circuit and device characteristics are investigated in a consistent manner.

• Earthquakes and Structures
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• v.8 no.1
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• pp.185-204
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• 2015

This study investigates the impact of the earthquake incident angle on the structural demand and the influence of ground motion selection and scaling methods on seismic directionality effects. The structural demand produced by Non-Linear Time-History Analyses (NLTHA) varies with the seismic input incidence angle. The seismic directionality effects are evaluated by subjecting four three-dimensional reinforced concrete structures to different scaled and un-scaled records oriented along nine incidence angles, whose values range between 0 and 180 degrees, with an increment of 22.5 degrees. The results show that NLTHAs performed applying the ground motion records along the principal axes underestimate the structural demand prediction, especially when plan-irregular structures are analyzed. The ground motion records generate the highest demand when applied along the lowest strength structural direction and a high energy content of the records increases the structural demand corresponding to this direction. The seismic directionality impact on structural demand is particularly important for irregular buildings subjected to un-scaled accelerograms. However, the orientation effects are much lower if spectrum-compatible combinations of scaled records are used. In both cases, irregular structures should be analyzed first with pushover analyses in order to identify the weaker structural directions and then with NLTHAs for different incidence angles.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.25-33
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• 2011

As chip operating frequency increases, there is growing concern about on-chip interconnect inductance. This paper presents a two-step inductance screening tool to select interconnects with significant inductance effects in a VLSI design. Test chips designed in different CMOS technology nodes are examined. The inductance screening results show that 0.1% of the nets in a design have inductance problems with chips running at its operating frequency, supporting the necessity of a screening process instead of adding inductance model to all the nets in the design. The increase in resistance due to geometry scaling will strongly affect the significance of inductance on delay as technology and frequency scale. Since higher frequency worsens inductance problem and geometry scaling alleviates it, inductance screening tool can provide useful guidelines to circuit designers.

• Korean Journal of Dental Materials
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• v.43 no.1
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• pp.17-28
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• 2016

The aim of this study was to evaluate the changes in dentinal permeability after application of dentin desensitizer on exposed dentin immediately after ultrasonic scaling to teeth with non-carious cervical lesions. Thirty caries-free extracted molars were fixed to slide glasses after horizontally being sectioned at 5 mm below the cemento- enamel junction (CEJ). The prepared specimen was connected to a fluid flow measuring device (nano-Flow), and a V-shaped cavity was formed at the CEJ to imitate the non-carious cervical lesion. After no fluid leakage was confirmed in the connected system with specimen, tooth surface was treated ultrasonic cleaning with piezoelectric ultrasonic scalers until dentinal tubules were exposed. And 6 different desensitizers were applied on exposed dentin. Real-time measurements of dentinal fluid flow were performed during ultrasonic scaling and application of dentin desensitizer. To evaluate the occlusion of exposed dentinal tubules, tooth surface was examined by SEM. Following results were observed. After ultrasonic scaling, more dentinal tubules were exposed on the tooth with non-carious cervical lesions compared to tooth without lesions. The rate of fluid flow measured with nano-Flow system had correlation with the degree of dentin occlusion observed with SEM after application of desensitizers on exposed dentin. Desensitizers with glutaraldehyde and HEMA did not decrease the rate of fluid flow and did not show dentin occlusion. Desensitizers with oxalate showed the limited effects on the rate of fluid flow and dentinal tubule occlusion. Desensitizer with resin monomer showed the significant effect on the rate of fluid flow and dentin occlusion.

• Journal of Periodontal and Implant Science
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• v.39 no.sup2
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• pp.239-251
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• 2009

Purpose: Full-mouth disinfection enables to reduce the probability of cross contamination from untreated pockets to treated ones, for completing the entire SRP under local anesthesia with chlorhexidine as a mouth wash in two visits within 24 hours. This study aimed to compare the clinical effects of modified full-mouth disinfection (Fdis) after 6 months with those of conventional SRP (cSRP). Methods: Thirty non-smoking chronic periodontitis subjects were randomly allocated two groups. The Fdis group underwent the entire SRP under local anesthesia in two visits within 24 hours, a week after receiving supragingival scaling. A chlorhexidine (0.1%) solution was used for rinsing and subgingival irrigation for Fdis. The cSRP group received SRP per quadrant under local anesthesia at one-week intervals, one week after they had received scaling. Clinical parameters were recorded at baseline, after 1, 3 and 6 months. Results: There are significant (P<0.05) decreases in the sulcus bleeding index, and plaque index, and the increases in gingival recession were significantly smaller with Fdis after six months compared with cSRP. There was significant improvement in the probing depth and clinical attachment level for initially medium-deep pockets (4-6mm) after Fdis compared with cSRP. Multi-rooted teeth showed significantly larger attachment gain up to six months after Fdis. Single-rooted teeth showed significantly more attachment gain, 1 and 6 months after Fdis. Conclusions: Fdis has more beneficial effects on reducing gingival inflammation, plaque level, probing depth, gingival recession and improving clinical attachment level over cSRP.

• Journal of Korea Game Society
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• v.10 no.1
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• pp.135-146
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• 2010

The development of image technologies in such area as broadcasting and movies has recently increased our attention to 3D stereoscopic images. In addition, the development of stereoscopic image representation technologies in 3D contents becomes more active over time due to the representational limitations of 2D images. Without limitation to the above-mentioned area, stereoscopic image technologies have been developed and studied so that they can be widely accessed in diverse areas including medical services and education. Due to the refined production, however, required to represent a three dimensional effects and the fatigue caused by the perception of a three dimensional effects, the stereoscopic image technologies are not combined into real time systems such as games where environments change unforeseeably. In this study we design a technique to adjust the depth scaling that will enable efficient management of a three dimensional effects and to relieve fatigue through automatic view point interval adjustment in accordance with situations based on the geometrical structure of the DirectX SDK graphic pipeline. Through this, we would like to suggest a new alternative idea to activate the production of games combined with stereoscopic image technologies.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.531-545
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• 1998

The objective of the present study was to evaluate the clinical and microbiological effects of scaling and root planing combined with local application of 2% minocycline gel to patients with moderate to advanced chronic adult periodontitis. 27 healthy patients with moderate to advanced chronic adult periodontitis were enrolled in the study. The quadrants that had 2 or more teeth with $5{\sim}8mm$ probing pocket depth and radiographic evidence of alveolar bone loss were selected and divided into test side and control side according to the splitmouth design. All patients received standardized oral hygiene instructions at the beginning of the study. Subsequently scaling and root plaining was performed on all remaining teeth until 0 week. The 2% minocycline gel was applied to periodontal pocket at 0, 1, 2, 3week in the test side. The normal saline was irrigated subgingivally for about 30 seconds in the control side. The clinical and microbiological analysis was carried out at 0, 4, 8, and 12weeks. The results of this st udy were as follows; 1.2% minocycline gel delivered subgingivally as an adjunct to scaling and root planing provided benefit in reducing sulcular bleeding index and pocket depth than the use of normal saline. 2. The relative proportion of cocci and non-motile bacteria was increased in the test and control groups with time, and there was no statistically significantdifference between two groups. 3. The proportion of spirochetes was slowly reduced in the control group, but, inthe test group, they were remarkably reduced from the 4th week, and there was a statistically significant difference between two groups. 4. In both groups, the relative proportion of motile rods was notably decreasedat the beginning of the study, and remained until 12th week in the test group,but, in the control group, they were slowly increased from the 4th weekand finally similar to that of the initial examination. In conclusion, local application of 2% minocycline gel may be effective in the clinical and microbiological aspects as an adjunct to scaling and root planing in periodontal disease sites.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.657-668
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• 2008

Purpose: In this study, we compared low-power $CO_2$ laser treatment to ultrasonic scaling, which is generally approved as a power-driven mechanical instrumentation, and evaluated both of these treatments regarding their clinical effectiveness and change in the volume of in GCF. Material and methods: 20 patients who had gingivitis were selected. all of patients has no systemic problems. Randomly selected, one quadrant received ultrasonic scaling only, another quadrant received ultrasonic scaling and $CO_2$ laser irradiation, the other quadrant received $CO_2$ laser irradiation only. Clinical parameters measured at baseline, 1 weeks, 2weeks, 4weeks and 8weeks. Result: Pocket probing depth and clinical attachment level were not changed during study period. Gingival index of all group were improved after treatment. At 1 weeks after treatment, Gingival index of ultrasonic scaling group was only significantly different compared to control group. At 2 weeks after treatment, gingival index of all experimental group were significantly different compared to control group. At 4 and 8 weeks after treatment, gingival index of all group were increased, but experimental group were lower than control group. Sulcus bleeding index was similar to the results of gingival index. At 1 weeks after treatment, all experimental group were significantly different compared to control group and it maintained during study. At 2 weeks after treatment, sulcus bleeding index of all group were lowest during study. Gingival crevicular fluid were measured with $Periotron^{(R)}$ 8000($Oraflow^{(R)}$, Inc. USA). At baseline, all group were showed moderately severe condition. At 1 week after treatment, laser treatment only group was reduced quantity of gingival crevicular fluid mostly, and all group were reduced quantity of gingival crevicular fluid. At 2 weeks after treatment, all group were health state. At 4 and 8 weeks after treatment, all group were showed recurrent of inflammation, and control group was the most significantly increased. Conclusion: This study showed that the effects of $CO_2$ laser treatment were similar to conventional ultrasonic scaling and this result remained longer than plaque control only. These results suggest possibility of $CO_2$ laser treatment for altered periodontal therapy.

• Journal of Korean society of Dental Hygiene
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• v.13 no.1
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• pp.114-121
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• 2013

Objectives : The purpose of the research is to measure Dental Hygiene students' level of musculoskeletal pain before and after receiving scaling training which involves repetitive operations and examine effects the operations have on the students' grip and pinch strength. Methods : 15 subjects in Dental Hygiene at Y university located in Chungbuk were tested on November 2, 2011. Results : 12 students had a musculoskeletal pain before receiving scaling training. However, all the 15 students had a musculoskeletal pain after the training. Body part the largest number of the students complained of the pain on was shoulders(37.9%) followed by neck(20.8%), waist(13.9%), wrists(10.3%), then back(6.9%) before receiving the training. Then the result showed that shoulders are where the largest number of students(24.1%) felt the pain, followed by neck(17.2%), wrists and fingers(13.8%), waist(12.1%), back and lower arms(6.9%), then palms(5.2%) after the training. Visual Analogue Scale(VAS) increased to $6.35{\pm}2.09$ after receiving the training from $3.31{\pm}3.38$ and this shows statistically significant difference(p<.001). Upon inspection, average grip strength decreased to $23.23{\pm}5.79kg$ from $25.00{\pm}4.51kg$ after receiving the training and this shows statistically significant difference(p<.05). Key pinch was the strongest among the three pinch strengths followed by tripod pinch then tip pinch. Average of all the three pinch strengths showed to have statistically significant difference before and after the training(p<.05); Tip pinch from $6.53{\pm}1.36$ to $5.87{\pm}1.3$, key pinch from $13.47{\pm}2.5$ to $12.53{\pm}2.30$, and tripod pinch from $9.27{\pm}3.04$ to $8.03{\pm}2.72$. Conclusions : The result showed that scaling training has effects on Dental Hygiene students' musculoskeletal subjective symptoms and their grip and pinch strength changes after receiving the training.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.24-34
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• 1995

The purpose of this study was to compare effects of demineralization of citric acid and tetracycline HCI on periodontally involved root surface. Twelve periodontally involved single rooted teeth were used. After scaling and root planing, root conditioning with citric acid and tetracycline HCI were carried and the teeth were processed scanning electron microscopic observation.The results were as follows: The scaled root surface was covered by much debris and calculus. The effect of demineralization of citric acid and tetracycline HCI was more reduced on scaling group than root planing group, because of hypermineralization of cementum surface and demineralization effect on root surface of tetracycline HCI showed tendency to reduction. The root planed group displayed more smooth root surface than scaling group, the surface was covered by smear layer, thus no exposure of dentinal tubule opening and collagen fiber, especially after root planing, citric acid and tetracycline HCl treated group showed exposure of dentinal tubule and collagen fiber, thus it was thought that new connective tissue attachment could be acquired.