• Title/Summary/Keyword: Area Ratio

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Usefulness of fractal analysis for the diagnosis of periodontitis (치주질환 진단시 프랙탈 분석의 유용성에 관한 연구)

  • Cha Sang-Yun;Han Won-Jeong;Kim Eun-Kyung
    • Imaging Science in Dentistry
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    • v.31 no.1
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    • pp.35-42
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    • 2001
  • Purpose: To evaluate the usefulness of fractal analysis for diagnosis of periodontitis. Materials and Methods : Each 30 cases of periapical films of male mandibular molar were selected in normal group and patient group which had complete furcation involvement. They were digitized at 300 dpi, 256 gray levels and saved with gif format. Rectangular ROIs (10×20 pixel) were selected at furcation, interdental crest, and interdental middle 1/3 area. Fractal dimensions were calculated three times at each area by mass radius method and were determined using a mean of three measurements. We compared fractal dimensions at furcation and interdental crest area of normal group with those of patient group. And then we compared ratio of fractal dimensions at furcation area, interdental crest area to interdental middle 1/3 area. Results: Fractal dimension at interdental crest area of normal group was 1.979±0.018 and that of patient group 1.971±0.012 (p>0.05). Fractal dimension at furcation area of normal group was 1.986±0.024 and that of patient group 1.974±0.015 (p<0.05). The ratio of fractal dimension at interdental crest area to interdental middle 1/3 of normal group was 1.003±0.015 and that of patient group 0.993±0.018 (p<0.05). The ratio of fractal dimension at furcation area to interdental middle 1/3 of normal group was 1.006±0.018 and that of patient group 0.994±0.018 (p<0.05). Conclusion : The ratio of fractal dimension at interdental crest and furcation area to interdental middle 1/3 area showed a statistically significant difference between normal and patient group. In conclusion, it is thought that fractal analysis might be useful for the diagnosis of periodontitis.

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A STUDY OF THE NORMAL & ABNORMAL OCCULSAL PATERNS IN ADULTS USING THE SUPERIMPOSED RUBBER PATTERN METHOD (Superimposed Rubber Pattern법에 의한 성인 정상 및 비정상 교합자의 교합 양상에 관한 연구)

  • Choi, Dae-Gyun;Lee, Sung-Bok;Kwon, Young-Hyuk;Choi, Boo-Byung
    • The Journal of Korean Academy of Prosthodontics
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    • v.33 no.3
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    • pp.467-491
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    • 1995
  • In order to analyze the occlusin of intercuspation with maximun bite force, fifteen healthy adult subjects with the ages 23 to 27 were studied(Group1 ; 5-normal occlusion with Angle's Class1, Group2 ; 5-Angle's Class2 malocclusion, Group3 ; 5-Angle’s Class3 malocclusion). Head Position was fixed with occlusal plane paralleling to horizontal line and occlusal registration r cord was made with polyether rubber impression material(Ramitec, ESPECo. West Germany). After all subject were trained for maximum intercuspation at least 5 times, occlusal registration procedure was repeated for this study. Lower posterior rubber occlusal registration records were sliced with 1mm thickness using precision metal sliding channel(Hitachi Ind. Co., Japan). Gross sectional drawings were traced from occluding view of upper and lower posterior teeth on the rubber slices using digitizer, and superimposed for the determination of each drawing distance(Superimposed Rubber Pattern Method). Based on superimposed rubber pattern drawings, total area of occlusal view, sum of each area of the 5 divided occlusal contact provinces and its ratio, total area and number of occlusal contact area were determined to elucidate occlusal stability in the normal and abnormal occlusion groups. The data were analysed by t-test(p=0.05) to determine statistical significance. The obtained results were as follows : 1. Group1 showed the largest standard area with occlusal view of the lower posterior teeth and Group3 showed the smallest area. There was a significant difference between Group2 and Group3(p=0.025), and Gropu1 was not statistically different for both Group2 and Group3. 2. Means and ratio of the under 2.0mm area(D) and ratio showed $197.49mm^2$, 59.76% in Group1, $188,69mm^2$, 56.10% in Group2, and $174.23mm^2$, 55.76% in Group3. The results that Group1 has the most area/ratio and Group3 has the least area/ratio can be considered Group1 is the most advantageous for masticatory effective area, and Group3 is the least adnantageous. 3. Means and ratio of the under 1.0mm area(C) were $198.96mm^2$, 42.65% in Group1, 123.06$mm^2$, 46.58% in Group2, and $92.24mm^2$, 29.52% in Group3. These data means that Group1 is the most advantageous in terms of masticatory effective area and Group3 is the least. 4. Means and ratio of the under 0.5mm area(B) were $86.68mm^2$, 26.68% in Group1, $62.98mm^2$, 18.71% in Group2, and $36.44mm^2$, 11.66% in Group3. These can also be considered Group1 is the most advantageous for masticatory effective area and occlusal stability. 5. Means and ratio of the under 0.05mm area(A) were $30.92mm^2$, 9.21% in Group1, $14.31mm^2$, 4.25% in Group2, and $7.59mm^2$, 2.43% in Group3. The area ratio of the each subject group was(4.1) : (1.9) : (1)and the data of the under 0.05mm area has the intimate relationship with inter-group and intra-group data/ratio. 6. First molar showed the most occlusal contact points in all subject group and Group1 showed somewhat uniformly distributed occlusal contact point except first premolar. In Group2, all contact point in posterior teeth showed significantly reduced distribution except first molar. Group3 showed evenly distributed contace points in first and second molars.

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An Experimental Study on the Damping Capacity of Lead Rubber Bearing with High Lead-plug Area Ratio (납-플러그 면적비가 큰 LRB의 감쇠능력에 관한 실험적 연구)

  • Choi, Jung-Ho;Kim, Woon-Hak
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.3 s.55
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    • pp.217-224
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    • 2009
  • Many engineering researches are performed to ensuring structural safety from earthquake. In this study, the damping capacity of LRB(lead rubber bearing) with high lead-plug area ratio was examined by hysteresis loop from experiments. The displacement controlled tests were performed for 12 specimens designed in 2 types by lead-plug area ratio as main parameter. Each coupled specimens were tested by 3 times sinusoidal loads with different loading velocities. From the experimental results, LRB with high lead-plug area ratio has sufficient damping ratio for reducing horizontal seismic load to structures.

A Study to Evaluate Impervious Area Ratio by Geographic Information Data (지리정보자료에 따른 불투수면적률 산정 결과에 대한 연구)

  • Min Suh Chae;Kyoung Jae Lim;Joong-Hyuk Min;Minji Park;Jichul Ryu;Mijin Lee;Sohyeon Park;Youn Shik Park
    • Journal of Korean Society on Water Environment
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    • v.39 no.2
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    • pp.142-152
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    • 2023
  • Infiltration is a process by which precipitation infuses into subsurface soils. The process determines the surface flow and baseflow volume, and it is one of most important hydrological processes regarding nonpoint source pollution management. Therefore, the Ministry of Environment has developed a guideline to determine the impervious area ratio to understand the hydrological process in administrative districts and watersheds. The impervious area ratio can be determined using land use or land cover maps. Three approaches were explored to determine the impervious area ratio in 25 districts in Seoul. The impervious area ratio was determined by employing the Land registration map and Land property data in the first approach, Land property map in the second approach, and Land cover map in the third approach. The ratio ranged from 38.96% to 83.01% in the first approach, 38.98% to 83.02% in the second approach, and 37.62% to 76.63% in the third approach. Although the ranges did not provide any significant differences in the approaches, some districts displayed differences up to 9.48% by the approach. These differences resulted from the fact that the data were land use or land cover, especially in the area of airport, residential complex area, and school sites. In other words, division of the pervious and impervious areas in an individual plot was not allowed in the Land registration map, while it was allowed in the Land cover map. Therefore, it was concluded that there is a need to revise the guideline so that a reasonable impervious area ratio can be determined in the districts.

Analysis of the Crop Damage Area Related to Flood by Climate Change Using a Constrained Multiple Linear Regression Model (구속 다중선형회귀 모형을 이용한 기후변화에 따른 농작물 홍수 피해 면적 분석)

  • Kim, Myojeong;Kim, Gwangseob
    • Journal of The Korean Society of Agricultural Engineers
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    • v.62 no.2
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    • pp.1-15
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    • 2020
  • In this study, the characteristics of crop damage area by flooding for 113 middle range watersheds during 2000-2016 were analyzed and future crop damage area by flooding were analyzed using 13 GCM outputs such as hourly maximum rainfall, 10-min maximum rainfall, number of days of 80 mm/day, daily rainfall maximum, annual rainfall amount associated with RCP 4.5 and RCP 8.5 scenarios and watershed characteristic data such as DEM, urbanization ratio, population density, asset density, road improvement ratio, river improvement ratio, drainage system improvement ratio, pumping capacity, detention basin capacity, and crop damage area by flooding. A constrained multiple linear regression model was used to construct the relationships between the crop damage area by flooding and other variables. Future flood index related to crop damage may mainly increase in the Mankyung watershed, Southwest part of Youngsan and Sumjin river basin and Southern part of Nackdong river basin. Results are useful to identify watersheds which need to establish strategies for responding to future flood damage.

Chip Forming Characteristics of Bi-S Free Machining Steel (Bi-S 쾌삭강의 칩생성특성)

  • 조삼규
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.3
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    • pp.48-54
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    • 2000
  • In this study the characteristics of chip formation of the cold drawn Bi-S free machining steels were assessed. And for comparison those of the cold drawn Pb-S free machining steel the hot rolled low carbon steel which has MnS as free machining inclusions and the conventional steels were also investigated. During chip formation the cold drawn free machining steels show relatively little change in thickness and width of chip compare to those of the conventional carbon steels. And a single parameter which indicates the degree of deformation during chip formation chip cross-section area ratio is introduced. The chip cross-section area ratio is defined as chip cross-section area is divided by undeformed chip cross-section area. The variational patters of the chip cross-section area ratio of the materials cut are similar to those of the shear strain values. The shear stress however seems to be dependent on the carbon content of the materials. The cold drawn Bi-S and Pb-S steels show nearly the same chip forming behaviors and the energy consumed during chip formation is almost same. A low carbon steel without free machining aids shows poor chip breakability due to its high ductility. By introducing a small amount of free machining inclusions such as MnS Bi, Pb or merely increasing carbon content the chip breakability improves significantly.

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An Analysis Model Study on the Vulnerability in the Infectious Disease Spread of Public-use Facilities neighboring Senior Leisure Welfare Facilities (노인여가복지시설 주변 다중이용시설에서의 감염병 확산 취약성 분석 모델에 관한 연구)

  • Kim, Mijung;Kweon, Jihoon
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.28 no.4
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    • pp.41-50
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    • 2022
  • Purpose: This study aims to suggest an analysis model finding the relationship between building scale characteristics of Public-use facilities and infectious disease outbreaks around senior leisure welfare facilities and the features and their scopes where quarantine resources are to be concentrated. Methods: Reviewing previous studies found the user characteristics of senior leisure welfare facilities and scale characteristics of urban architectures. The data preprocessing was performed after collecting building data and infectious disease outbreak data in the analysis area. This study derived data for attributes of building size and frequency of infectious disease outbreaks in Public-use facilities around senior leisure welfare facilities. A computing algorithm was implemented to analyze the correlation between the building size characteristics and the infectious disease outbreak frequency as per the change of the spatial scope. Results: The results of this study are as follows: First, the suggested model was to analyze the correlation between the infection frequency and the number of senior leisure welfare facilities, the number of Public-use facilities, building area, total floor area, site area, height, building-to-land ratio, and floor area ratio varied as per the change of spatial scope. Second, correlation results varied between the infection frequency and the number of senior leisure welfare facilities, the number of Public-use facilities, building area, total floor area, site area, height, building-to-land ratio, and floor area ratio. Third, a negative correlation appeared in the analysis between the number of senior leisure welfare facilities and infection frequency. And positive correlations appeared noticeably in the study between the number of Public-use facilities, building area, total floor area, height, building-to-land ratio, and floor area ratio. Implications: This study can be used as primary data on the utilization of limited quarantine resources by analyzing the relationship between the Public-use facilities around the senior leisure welfare facilities and the spread of infectious diseases. In addition, it suggests that infectious disease prevention measures are necessary considering the spatial scope of the analysis area and the size of buildings.

Analysis of the Regional Effectiveness of Urban Wall-Planting Applied by a Biotope Area Ratio - Case of Jung-gu District in Seoul - (생태면적률 적용을 통한 도시 내 벽면녹화의 지역적 효과 분석 - 서울시 중구를 사례로 -)

  • Kang, Tae-Sun;Lee, Myung-Woo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.5
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    • pp.88-100
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    • 2014
  • The purpose of the study is to analyze the regional effectiveness of wall-plantings by applying a biotope area ratio when wall-plantings are constructed in high density areas. For this, this study required a sample of the wall-planting's regional plan. Therefore, types of wall-planting were determined and applied to a sample site. Four types of wall-plantings were developed by formative features and functional features. Type "A" had simple and functional features, Type "B" had both mixed and functional features, Type "C" had both simple and landscape features and Type "D" had mixed and landscape features. Jung-gu District in Seoul was chosen as the sample site. Total investigations were performed three times for three months from June to August, 2011. Total green-able walls were located in 498 places with a total length of 8,449m and gross vertical area of $23,754.90m^2$. The classification results of total green-able walls by the four types were Type "A" at $1,936.65m^2$, Type "B" at $5,875.30m^2$, Type "C" at $12,487.85m^2$ and Type "D" at $3,455.10m^2$. This study analyzed how all facade areas of the green-able walls impacted the biotope area ratio at the site. First, the biotope area ratio regarding all the zones in Jung-gu District was defined as the gross biotope area ratio while the biotope area ratio regarding all of the artificial zones was defined as the net biotope area ratio. In the case of the gross biotope area ratio, 17.97% is current ration with a projected increase to 0.10% after wall-planting. In the case of the net biotope area ratio, 4.73% is the current ration with a projected increase to 0.11% after wall-planting. This 0.11% is about 2.28% of 4.73%. This study looks at all wall-plantings that have been constructed throughout a high density area to observe their impact on the improvement of ecological function therein. With consideration of the landscape value of the facade, the regional effectiveness of wall-planting is expected to increase even more.

Study of Improving the Biotope Area Ratio System for Urban Agriculture Vitalization - Focus on Daylight Condition Analysis- (도시농업 활성화를 위한 생태면적률 제도개선에 관한 연구 -단지내 일조조건 분석을 중심으로-)

  • Lee, Gunwon;Jeong, Yunnam;Min, Byunghak;Kim, Seiyong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.12
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    • pp.7393-7402
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    • 2014
  • This study focused on improving the Biotope Area Ratio, which has existing availability as a legal and institutional method for the architectural and urban fields to respond rapidly to recently growing demands for urban agriculture. The existing Biotope Area Ratio indicators only considers the depth and permeability of soil among a range of conditions for plant growth; they can be used for landscaping plants management but have difficulties in dealing with plants that are the major factors in urban agriculture. This study aimed to verify this hypothesis and suggest a direction of improvement in the Biotope Area Ratio. The study discovered that the management of plant growth only using the Biotope Area Ratio indicators has limitations.

A Study on the Energy Load of the Curtain Wall Buildings according to the Application of the Double-skin Facade System (커튼월 건축물의 이중외피 시스템 적용에 따른 에너지 부하량 검토)

  • Li, Bai-Hong;Lee, Jun-Gi;Kim, Sung-Hoon;Lee, Gab-Taek;Kim, Dong-Wan;Lee, Kyung-Hee
    • Journal of Power System Engineering
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    • v.20 no.6
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    • pp.99-104
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    • 2016
  • In this study, we researched the energy load according to the change of the inner window area ratio, the distance of the air gap and the azimuth of the curtain wall building, which installed the multistory double-skin facade(DSF). and we compared the results with the no double-skin facade situation as follows. With the DSF, it is better than other case, when the window area ratio is 40% and the air gap is 1.2m on the west, south-45-west, south-45-east and east. And it's best when the window area ratio is 40% and the air gap is 0.4m on the south. And on the east or south-45-east, the window area ratio is 40% and the air gap is 1.2m is better than other case with the DSF. On south, it is best when the window area ratio is 100% without DSF. On the south-45-west or west, it is best when the window area ratio is 40% without the DSF.