• 한국통신학회논문지
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• 제25권10B호
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• pp.1832-1840
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• 2000

The error diffusion algorithm is good for reproducing continuous images to binary images. However the reproduction of edge characteristics is weak in power spectrum an analysis of display error. In this paper an edge enhanced error diffusion method is proposed to improve the edge characteristic enhancement. Spatial gradient information in original image is adapted for edge enhance in threshold modulation of error diffusion. First the horizontal and vertical second order differential values are obtained from the gradient of peripheral pixels(3x3) in original image. second weighting function is composed by function including absolute value and sign of second order differential values. The proposed method presents a good visual results which edge characteristics is enhanced. The performance of the proposed method is compared with that of the conventional edge enhanced error diffusion by measuring the edge correlation and the local average accordance over a range of viewing distances and the RAPSD of display error.

• 치과방사선
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• 제12권1호
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• pp.63-67
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• 1982

The author modified the Aquard 100 head holder device from Denar Co. to be adequate to the Koreans and to enhance the standardization and reproducibility of the temporomandibular joint radiographs. The results were obtained as follows; 1. The projected central ray was at an angle of 25 degrees. 2. Standardization of patients head position was obtained by means of vertical and horizontal bar which were attached to the head holder. 3. Arbitrary 3 points (A.B.C.) which were on the TMJ area of dry skull were measured for the identification of reproducibility. 4. Measured distances in dry skull were as follow; A-B, 28.0±0.25, B-C 11.9±0.25 and C-A 30.4±0.21, in closed position.

• 자원환경지질
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• 제32권4호
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• pp.365-371
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• 1999

Ture diplacement of a fault monement is calculated from the displacement of the index plane such as bedding on an outcrop surface. The input parameters are the orientations of the index, fault, and outcrop planes. It is also necessary to input the orientation of fault striation and the offset distance of the index plane on the outcrop surface. The distances of the total, strike, horizontal and dip slip components of the fault movement are calculated from the input parameters. Hwang(1998) conducted a simlar calculation using trigonoment method. To apply the previous method, the offset distance of the index plane must be measured on a vertical outcrop surface. The calculation method of this study accepts the offset distence of index plane on an outcrop plane of any orientation. Calculation results from both method are indentical, regardless of the simplicity of the new method.

• 한국가스학회지
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• 제19권1호
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• pp.51-56
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• 2015

To assess downward positions of water spray for the small-scale release of chlorine gas, dispersion coefficients for the Gaussian dispersion model were validated at the small-scale release experiment. And the downwind distances of water spray were assessed with the simulated results. As results, the Gaussian plume model using the Briggs' dispersion coefficient well estimated the dispersed characteristics for small-scale release of chlorine gas. The best adequate downwind position of water spray is the position of the maximum concentration of chlorine at the ground level. And the adequate vertical and horizontal dimensions of water spray consider the maximum width and height of cloud.

• 한국환경농학회지
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• 제28권4호
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• pp.340-346
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• 2009

Chromated copper arsenate (CCA) is a chemical wood preservative that has been intensively used to protect wood from decay during the last few decades. CCA is widely used to build structures such as decks, fences, playgrounds and boardwalks. However, structures constructed of CCA-treated wood have caused adverse environmental effects due to leaching of Cr, Cu and As into surrounding soils. This research was conducted to monitor the vertical and horizontal distribution of Cr, Cu and As in soils adjacent to CCA-treated wood structures in Korea. Two structures constructed with CCA-treated wood were selected at Hongcheon and Chuncheon in Gangwon Province, South Korea. Eleven soil profile samples were collected at depths of 0 to 80 cm at each site, while 12 surface soil samples were collected at distances of 0 to 200 cm from each structure. The soil chemical properties, soil particle size distribution and total metal concentrations were then determined. The results revealed that soils near CCA-treated wood structures were generally contaminated with Cr, Cu and As when compared to the background concentration of each metal. In addition, the concentrations of Cr, Cu and As in soils decreased as the vertical and horizontal distance from the structure increased. Further studies should be conducted to evaluate the mobility and distribution of these metals in the environment as well as to develop novel technologies for remediation of CCA contaminated soils.

• Imaging Science in Dentistry
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• 제50권2호
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• pp.117-124
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• 2020

Purpose: The purpose of this study was to evaluate possible differences in the location of the inferior alveolar canal in male and female Egyptians. Materials and Methods: This cross-sectional retrospective study involved the evaluation of 210 CBCT scans of Egyptian individuals (18-70 years old). The inferior alveolar canal was localized by measuring 8 linear dimensions: 2 for the vertical localization of the mental foramen (superior and inferior to the mental foramen), 4 at the first molar bifurcation for the vertical and horizontal localization of the inferior alveolar canal (superior, inferior, buccal, and lingual to the inferior alveolar canal), and 2 for the horizontal localization of the mandibular foramen (anterior and posterior to the mandibular foramen). The measurements were statistically analyzed via comparative analysis, stepwise logistic regression, and receiver operating characteristic (ROC) curve analysis. Results: Six of the 8 measured distances differed to a statistically significant extent between the sexes. Regression analysis suggested a logistic function with a concordance index of 84%. The diagnostic accuracy capabilities of the linear measurements as sex predictors were calculated using ROC analysis, and the 6 best predictors for sex determination were selected and ranked from highest to lowest predictive power. Moreover, combining these 6 predictors increased the predictive power to 84%. Conclusion: The location of the inferior alveolar canal in the Egyptian population varies significantly by sex; accordingly, this anatomic landmark could be used as a reliable indicator of sexual dimorphism.

• Structural Engineering and Mechanics
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• 제61권4호
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• pp.527-538
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• 2017

The evaluation of the loss-of-support conditions of frictional beam-to-column connections using simplified numerical models describing the transverse response of a portal-like structure is presented in this paper considering the effects of the seismic-hazard disaggregation. Real earthquake time histories selected from European Strong-motion Database (ESD) are used to show the effects of the seismic-hazard disaggregation on the beam loss-of-support conditions. Seismic events are classified according to different values of magnitudes, epicentral distances and soil conditions (stiff or soft soil) highlighting the importance of considering the characteristics of the seismic input in the assessment of the loss-of-support conditions of frictional beam-to-column connections. A rigid and an elastic model of a frame of a precast industrial building (2-DoF portal-like model) are presented and adopted to find the minimum required friction coefficient to avoid sliding. Then, the mean value of the minimum required friction coefficient with an epicentral distance bin of 10 km is calculated and fitted with a linear function depending on the logarithm of the epicentral distance. A complete parametric analysis varying the horizontal and vertical period of vibration of the structure is performed. Results show that the loss-of-support condition is strongly influenced by magnitude, epicentral distance and soil conditions determining the frequency content of the earthquake time histories and the correlation between the maxima of the horizontal and vertical components. Moreover, as expected, dynamic characteristics of the structure have also a strong influence. Finally, the effect of the column nonlinear behavior (i.e. formation of plastic hinges at the base) is analyzed showing that the connection and the column are a series system where the maximum force is limited by the element having the minimum strength. Two different longitudinal reinforcement ratios are analyzed demonstrating that the column strength variation changes the system response.

• Journal of Oral Medicine and Pain
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• 제13권1호
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• pp.13-21
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• 1988

The author studied the vertical height of tooth crown and the amounts of alveolar bone resorption with age. All 84 subjects(44 male, 40female) who visited Dental hospital of Wonkwang University with no history of sever periodontal disease and no experience of periodontal surgery. 84 subject were divided into 3 groups by age, that is, group I(28-32yrs), group II(38-42yrs), and group III(48-52yrs). Informal radiogram with bite wing film(horizontal angulation : $0^{\circ}$, vertical angulation : $+5^{\circ}~+10^{\circ}$) were taken on premolar and molar area. The distances from cusp tip to cementoenamel junction (vertical height of tooth crown) and from cementoenamel junction alveolar crest(amount of alveolar bone resorption) were measured, and then recorded data from 946 teeth were statistically analysed. This study was undertaken to obtain the data for age estimation by the changes of tooth crown height and alveolar bone resorption in the point of forensic odontology. The obtained results were as follows : 1. The average crown height of mandibular right 1st. molar was 7.1mm in group I, 6.7mm in group II, and 6.6mm group III, and the average amount of alveolar bone resorption on mandibular right 1st. molar were 1.8mm in group I, 2.5mm in group II, and 3.0mm in group III. Ratio of tooth crown height to amount of alveolar bone resorption was 4.0:1 in groupI, 2.7:1 in group II, and 2.2:1 in group III, the ratio was decreased with age. 2. In comparison with upper teeth and lower teeth in ipsilateral side, the average value of tooth crown height and amount of alveolar bone resorption were slightly higher in upper arch than those in lower arch, but there was not a statistically significant difference. 3. The ratio of height of tooth crown to amount of alveolar bone resorption was decreased with age, and which depended mainly upon the change of amount of alveolar bone resorption rather than the change of tooth crown height.

• 한국안광학회지
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• 제15권1호
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• pp.117-122
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• 2010

목적: 정상인 청년 62명(남: 29, 여: 33)을 대상으로 단안운동과 양안운동 시에 외안근의 운동력을 조사하고자 실시하였다. 방법: 단안운동력 검사에서는 우 좌안의 내전과 외전 그리고 상전과 하전능력을 제 l안위에서의 각막윤부를 기점으로 한 둔동거리로 측정하였고 양안운동력 검사에서는 우 좌안의 상사근과 하사근의 운동능력을 각막 윤부간 거리차로 측정하였으며 데이터 값은 고해상도 디지털 카메라를 이용하여 사진데이터를 얻은 후 high resolution digital image process를 거쳐 처리하였다. 결과: 조사대상 남여의 단안운동기능은 우 좌안에서 각각 외전능력은 (남) 9.35 mm. 9.75 mm. (여) 9.02 mm. 9.52 mm 이고, 내전능력은 (남) 10.23 mm. 10.16 mm, (여) 10.17 mm, 10.07 mm이었으며 상전능력은 (남) 7.01 mm, 6.91 mm, (여) 6.98 mm, 6.64 mm이고 하전능력은 (남) 7.52 mm. 6.82 mm, (여) 7.52 mm, 6.67 mm이었다. 조사대상자의 양안운동기능은 우 좌안에서 각각 하사근은 54.8% 기능항진, 45.1% 기능저하/67.7% 기능항진, 32.2% 기능저하이고, 상사근의 경우는 64.5% 기능항진, 35.5% 기능저하/58.1% 기능항진, 41.9% 기능저하이었다. 결론: 수평운동능력이 수직운동능력보다 더 우세하였으며, 수평운동에서는 내전능력이 외전능력보다 약간 더 우세하였고 수직운동에서는 하전능력이 상전능력보다 약간 더 우세하였다. 우 좌안의 하사근 모두 기증항진의 경우가 더 높은 비율로 나타났다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.15.1-15.6
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• 2018

Background: The purpose of this study was to identify the location of the antilingula, lingula, and mandibular foramen in Korean cadavers and to promote safe and accurate surgery without damage to the inferior alveolar neurovascular bundle (IANB) when performing a vertical ramus osteotomy (VRO). Methods: This study was conducted on the dried mandibles of 20 adult cadavers. Digital calipers were used to measure the distances from the anatomical reference points (antilingula, lingula, and mandibular foramen). Result: The antilingula was located at the anterior 44% and superior 31% in the ramus. The lingula was located at the anterior 55% and superior 30% in the ramus. The mandibular foramen was located at the anterior 58% and superior 46% in the ramus. Regarding the positional relationship with the antilingula, the lingula was located 0.54 mm superior and 4.19 mm posterior, and the mandibular foramen was located 6.95 mm inferior and 4.98 mm posterior. The results suggested that in order to prevent damage to the IANB, osteotomy should be performed in the posterior region of ramus at least 29% of the total horizontal length of the ramus. Conclusion: Using only the antilingula as a reference point is not guaranteed to IANB injury. However, it is still important as a helpful reference point for the surgeon in the surgical field.