• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.668-678
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• 1995

In order to evaluate the therapeutic effect of argon laser irradiation on hypersensitive root, 60 mandibular premolars that had been extracted due to periodontal disease were treated by thorough scaling, root planing and root conditioning with tetracycline HCI(100mg/ml, 5 min.) for induction of hypersensitive root. Within middle one third of root mesial surface(30) or distal surface(30) was randomly irradiated by 0.5W-, 0.75W- and 1.0W-power for 2 minutes argon laser(HGM Inc., USA) with or without topical application of 1.23% acidulated phosphate fluoride gel(Pascal, USA). After all teeth were maintained in 2% methylene blue solution for 48 hours and cross-sectioned through irradiated surface of dried roots, methylene blue stained area was compared between irradiated side and nonirradiated side. Following results were obtained : 1. Methylene blue stained area was significantly less in the laser irradiated group than control group(p<0.05). 2. There was no significant difference in methylene blue stained area between 0.5W-power and 0.75W-power group(p>0.1) and between 0.75W-power and 1.0W-power group(p>0.1), but there was significant difference between 0.5W-power and 1.0W-power group(p<0.05). 3. There was no significant difference in methylene blue stained area between two groups with and without topical application of 0.12% acidulated phosphate fluoride gel(p>0.1). The results suggest that argon laser irradiation on hypersensitive root may reduce the hypersensitivity by obstruction of dentinal tubules.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.32-35
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• 2011

Experimental studies were carried out in an explosion chamber to investigate the influences of multiple cylinder obstacles on local flame propagation. The chamber dimension is 235 mm in height with a $1,000{\times}950\;mm^2$ rectangular cross section and a large vent area of $1,000{\times}320\;mm^2$. Multiple cylinder bars with obstruction ratio of 30% were used. In order to examine the interaction between the propagating flames and the obstacles, temporally resolved flame front images were recorded by a high speed video camera. The propagation behaviour of local flame fronts around the left obstacle was analyzed in terms of two different methods such as the incremental burnt area divided by the flame front length and the average of the local propagation velocity determined at each point along the flame front. It was found that two methods give good consistency.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.299-311
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• 2011

The objective of this paper is to present a methodology for the classification of spatial patterns considering the parameters of urban form which play a significant role in the formation of the urban climate. The urban morphological parameters, i.e. building coverage, impervious pavement, vegetation, water, farmland and landuse types were used to classify the spatial patterns by a K-means cluster analysis. And the presented methodology was applied on Changwon city, South Korea. According to the results of cluster analysis, the total spatial patterns were classified as 24 patterns. First of all, The spatial patterns(A-1, A-2, A-3, B-1, B-2, B-3, C-1, C-2, C-3, D-1, D-2, D-3, E-1, E-2, E-3, F-1, F-2, F-3, G-1, G-2, G-3), which distributed in the rural area and the suburban area, can have the positive impacts of cold air generation and wind corridor on an urban climate environment, were distributed in the rural area. On the other hand, the spatial patterns of the downtown area including A-4, B-4, C-4 and D-4 are expected to have the negative impacts on urban climate owing to the of artificial heat emission or the wind flow obstruction. Finally, it will require the future research to analysis the climatic properties according to the same spatial patterns by the field survey.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.105-115
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• 2020

Purpose: This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class II, and class III malocclusions. Eight linear and 2 angular hyoid parameters(H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean crosssectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with P values <0.05 indicating statistical significance. Results: The mean airway volume differed significantly among the malocclusion classes(P<0.05). The smallest and largest volumes were noted in class II (2107.8±844.7 ㎣) and class III (2826.6±2505.3 ㎣), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class II and III malocclusions and between H-Y and upper airway length in class I malocclusions. Conclusion: The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.

• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.339-349
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• 2017

In this paper, we propose a technique for smoothly replacing a signboard image in a video clip with another signboard image and an application for performing it. In order to replace the signboard area in the image, it must be tracked and the shape of the signboard changed. Also, when an obstruction occurs due to a front object, the obscured area is extracted so that only the signboard area can be replaced, and color correction is performed for natural synthesis. The proposed application receives the information required by the algorithm from the user and explains the required functions, thereby disclosing the entire process in which the algorithm is actually implemented and tested. This can be used for a variety of media, and can be used as a means to remove the indirect advertisement that is often seen, and it can also be used as a new advertisement model in which another advertisement image is inserted into the image to be advertised.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.147-154
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• 2008

A variety of activity happens around the sidewalk in the city. Particularly, a large variety of activity happens in shopping area, but it causes an obstruction of economical revitalization since the pedestrians require time and cost to find what they want. So, this study will develop the path searching method to minimize the economical loss of shoppers by providing the significant path and supporting the walking movement. Firstly, consider existing network expression techniques and approach three points which are physical and environmental factor, the recognition of the pedestrians' space when changing the direction, and the recognition of restriction of vision and accessibility. Try to design the network DB and simulate the algorithm. As a result, it is now possible to do the path searching that considers variety of recognition factors and show the method how to make the path-searching algorithm for pedestrian.

• Water for future
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• v.28 no.6
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• pp.119-131
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• 1995

Two-dimensional diffusion and kinematic hydrodynamic models have been studied for preparing the flood inundation map. The models have been tested by applying to one-dimensional dam-break problem. The results have good agreements compared with those of dynamic wave model. The diffusion wave model produces the mass conservation error close to zero. Floodwave analyses for two-dimensional floodplain with obstruction and channel-floodplain show both stable and efficient results. The model presented in this study can be used for flood inundation map and flood warning system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3350-3365
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• 2020

A considerable literature has recently grown up on the theme of ship wireless communications. However, much of the research up to now has been descriptive in the offshore area. There has been little quantitative analysis of wireless communication in inland waterways, which has received considerable attention lately. Until now, only the effects on inland river environment are examined. What is less clear is the nature of channel change caused by the antenna movement. Here we explore the moving ship-to-fixed-ship fading characteristics at 5.9 GHz for an inland waterway in the city center of China. The ship motion trajectory is designed in order to determine the effect of changes in the antenna position. We evaluate the channel fading characteristics of inland waterway, which are highly correlated with the distance between transmitter and receiver. We demonstrate that the line-of-sight component, as well as the components from multipath with obstruction reflections, contributes largely to the mean power gap. Our findings reveal critical ship-to-ship characteristics in inland waterway, which definitely contribute to the field of ship wireless communications.

• Korean Journal of Head & Neck Oncology
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• v.32 no.1
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• pp.49-52
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• 2016

The lobular capillary hemangioma (LCH) was previously known to pyogenic granuloma and is benign vascular lesion which grows rapidly on skin and mucosa. It arises from whole body, but oral and nasal cavities are most predilection sites in the head and neck area. The laryngeal LCH looks like a granulomatous lesion of posterior glottis and its common etiology are tracheal intubation and laryngopharyngeal reflux disease etc. The LCH in larynx can cause blood tinged sputum and lump sense. The lesions refractory to medical therapy or causing dyspnea may require surgical excision. A 74-year-old man who presented gradually aggravated dyspnea, lump sensation and hoarseness of one month came to our hospital. The stroboscopic examination revealed large well-margined glottic mass. It was excised with $CO_2$ laser and finally diagnosed as LCH. We present a rare unique case of glottic LCH with a review of literatures.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1335-1340
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• 2013

Herein the water film was introduced to the hydrophilic area on the line patterned surface to solve the contradiction caused by surface roughness (high different wettability has advantage to control the droplet but high roughness for that high wettability difference causes obstruction of droplet moving). Thus the droplet on the water film could not be hindered to line direction but restricted to orthogonal direction, effectively. In addition, droplet behaviors according to droplet volume and line thickness were studied. Droplet fell off the line with narrowing the interface between the droplet and the water film on the line. When the droplet fell off the line, the plate angle was designated as a critical plate angle and it used as an indicator of surface capability to control the droplet. As a result critical plate angle increases as droplet volume decreases and line thickness increases.