• Title/Summary/Keyword: two dimensions

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Prediction of osteoporosis using fractal analysis et cetera on panoramic radiographs (파노라마 방사성사진에서 프랙탈 분석 등을 이용한 골다공증 예측)

  • Kim, Joo-Yeon;Nah, Kyung-Soo
    • Imaging Science in Dentistry
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    • v.37 no.2
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    • pp.79-82
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    • 2007
  • Purpose: The purpose of this study was to investigate whether panoramic radiographs were useful in predicting osteoporosis. Materials and Methods: 50 postmenoposal women between the age of 41.8 and 78.5 were classified as normal and osteoporosis groups according to the bone mineral density of lumbar vertebrae. Panoramic radiographs were taken. Age, body mass index, remaining mandibular teeth, mandibular cortical thickness and morphology, and fractal dimensions at periapical areas of mandibular first molars were evaluated to differentiate the two groups. Results: The age of osteoporotic group was statistically significantly higher than that of normal group (p<0.05), but not the body mass index or number of remaining mandibular teeth. The mean fractal dimension of osteoporotic group was $1.391{\pm}0.085$, and was significantly lower than that of the normal group, which was $1.523{\pm}0.725$ (p<0.01). Thick mandibular cortical thickness was common in normal group, whereas thin or very thin mandibular cortical thickness was common in osteoporotic group and the difference was significant (p < 0.05). C2 pattern was common in normal group followed by C1, whereas C2 was common in osteoporotic group followed by C3. The difference was statistically significant (p< 0.0 1). Conclusion: Age, mandibular cortical thickness and shape, fractal dimension on panoramic radiographs were useful in predicting osteoporosis.

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Architecture and Language: Theories and Practice in Architecture since the 1960s. (건축과 언어: 1960년대 이후 서구건축의 이론과 실험)

  • 김성홍
    • Lingua Humanitatis
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    • v.1 no.2
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    • pp.107-121
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    • 2001
  • This paper examines the way in which the idea of language has been introduced in architectural discourse since the late 1960s. The paper reviews the works of Robert Venturi, Charles Jencks, Peter Eisenman, Alan Colquhoun, and Mario Gandelsonas, which explore the analogy between linguistic and architectural form. All of the writers above are responsive to each other's theoretical positions, sometimes implicitly and sometimes explicitly. A system of signs can be approached by asking how the lexicon and syntax are proportioned. The same question may be posed to architecture: can architecture be understood as a lexicon or as a relational structure, such as language is\ulcorner Two perspectives are presented by architectural theorists. The first advocated by Venturi and Jencks posit architectural form as a problem of signs. The problem with this perspective is that, it reduces architecture into popularized iconography in favor of the representational aspects of architectural form. The second perspective, developed by Eisenman, explores the possibility of finding new formal constructs in the abstract relationship of formal properties. Eisenman's theory, however, has its own problems for, in highlighting syntactic structure, it minimizes the distinction between the perceptual and the pragmatic dimensions. Yet both perspectives address crucial problems of contemporary architecture and expand architectural discourse into the broader realm of humanistic studies.

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Poly-gate Quantization Effect in Double-Gate MOSFET (폴리 게이트의 양자효과에 의한 Double-Gate MOSFET의 특성 변화 연구)

  • 박지선;이승준;신형순
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.8
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    • pp.17-24
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    • 2004
  • Quantum effects in the poly-gate are analyzed in two dimensions using the density-gradient method, and their impact on the short-channel effect of double-gate MOSFETs is investigated. The 2-D effects of quantum mechanical depletion at the gate to sidewall oxide is identified as the cause of large charge-dipole formation at the corner of the gate. The bias dependence of the charge dipole shows that the magnitude of the dipole peak-value increases in the subthreshold region and there is a large difference in carrier and potential distribution compared to the classical solution. Using evanescent-nude analysis, it is found that the quantum effect in the poly-gate substantially increases the short-channel effect and it is more significant than the quantum effect in the Si film. The penetration of potential contours into the poly-gate due to the dipole formation at the drain side of the gate corner is identified as the reason for the substantial increase in short-channel effects.

A Study on the Prevalence and Predictors of Problem Drinking among High School Students in Korea (청소년기 문제성 음주 실태와 결정요인에 관한 연구)

  • Jang, Seung-Ock
    • Korean Journal of Social Welfare
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    • v.42
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    • pp.372-396
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    • 2000
  • This study focuses on high school students and aims not only to examine the relationships among problem drinking measures and drinking motives to cope but also to determine the factors to predict the negative consequences related to alcohol. 1,436 self-reported questionnaires were collected from seven big cities' high school students who had ever experienced drinking. The survey data identified the following results; first, there were statistically significant differences in drinking motives to cope and 4 measures of problem drinking depending on gender and the school type. It should be noted that more girls and more students in vocational schools had experienced drunkenness rather than boys and students in academic schools unlike alcohol consumption, binge drinking, and negative consequences related to alcohol. Second, the use of alcohol to cope may place individuals at greater risk for alcohol problems. Four dimensions of problem drinking are moderately correlated to drinking motives to cope. Third, the result from logistic regressions indicated that factors related to drinking (binge drinking, drunkenness, and drinking reasons to cope) rather than demographic factors would be contributed more to one more as well as two more negative consequences. Especially, drunkeness seems to be the best factor to predict negative consequences related to alcohol. Implications for developing prevention programs are suggested.

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Alterations of the soft tissue dimensions around implant-supported singletooth replacements in the maxillary anterior region - A retrospective longitudinal study - (상악 전치부 임플란트지지 수복금관의 주변 연조직 제원 변화에 관한 누년적 연구)

  • Chang, Moon-taek
    • Journal of Periodontal and Implant Science
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    • v.28 no.3
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    • pp.507-517
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    • 1998
  • This study was performed to investigate the soft tissue changes around single implant-supported crowns during followup periods. Twenty patients(31 implants) whose single missing tooth in the maxillary anterior region had been replaced with an single implant-supported crown were recruited for the study. Crown length, soft tissue level and papilla height at the single implant-supported crowns were measured at follow-up examination and calculated from the slides taken at time of crown placement. as well Papilla index was scored from the slides taken at the time of crown placement and follow-up examination. A very little amount of recession occurred and the soft tissue level moved more apically and the papilla height increased significantly (p<0.01). Especially, both mesial and distal papilla index at single implant-supported crowns increased significantly during follow-up periods (p<0.001). When the two slides taken at the time of crown placement and follow-up were compared simultaneously, except one site, papillae size increased at all sites. From the results of the study, the interdental papillae at the single implant-supported crowns seemed to regenerate significantly and their crown margins were stable during follow-up periods. Hence it is indicated that various surgical interventions at on early stage to enhance soft tissue esthetics arourd single implants may be unnecessary.

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Monoethanolamine Hydrobromide의 結晶 構造

  • Chung Hoe Koo;Chuhyun Choe;Tae Sun Roe;Hoon Sup Kim
    • Journal of the Korean Chemical Society
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    • v.18 no.1
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    • pp.25-30
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    • 1974
  • The crystal and molecular structure of monoethanolamine hydrobromide, HOCH2CH2NH2 HBr, has been determined by X-ray diffraction methods. The crystals are triclinic, space group Pi and unit cell contains two formula units and has dimensions a = 4.54, b = 7.45, c = 7.76${\AA}$ and ${\alpha}$ = 102.5, ${\beta}$=93.6, ${\gamma}=78.7^{\circ}$. The present structure determination confirmed that the structure of monoethanolamine hydrobromide is isomorphous with that of monoethanolamine hydrochloride.

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Analysis of the Types of Fractal Dimension Appeared in Fashion (패션에 나타난 프랙탈 디멘션의 유형분석)

  • Song, Arum;Kan, Hosup
    • Journal of Fashion Business
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    • v.22 no.1
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    • pp.135-147
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    • 2018
  • Since the 20th century, there has been a growing interest in the new concept of fractals, a combination of mathematics and art, and the attempt to study the creative spatial aspects of the concept is being made. The purpose of this research is to examine artistic characteristics of fractal dimension and then analyze the types of fractal dimensions expressed in the fashion. Previous literature on fractals and dimension, and visual data on art and fashion collected over the Internet were used for analysis. Fractal dimension refers to the spatial concept of structural dimension of geometrical self-similarity. An analysis of the types of fractals seen in fashion revealed spatial expansion, the repetition in continual figures, superposition accordant to different sizes, and shades of different shapes. The aesthetic characteristics of fractal dimension appearing in fashions were examined based on analyses of fractal dimension types; the inherent characteristics of self-similarity, superimposition, and atypicality were found. Results obtained from this study are expected to be used as basic materials for the application of the design of fractal dimension into various perspectives of fashion.

Attitudes Toward General Elders and Elders with Dementia Among Baccalaureate Junior Nursing Students (간호학사 과정 3학년 학생들의 노인과 치매노인에 대한 태도)

  • Kim, Jung-Hee
    • Research in Community and Public Health Nursing
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    • v.18 no.4
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    • pp.601-610
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    • 2007
  • Purpose: This study investigated attitudes toward general elders and elders with dementia among nursing students before beginning the clinical practicum. In addition, students' characteristics differentiating the attitudes were examined. Methods: Attitudes were measured with questionnaires developed for Asian culture at the beginning week of the first semester of the junior year in two baccalaureate programs. Responses from 120 out of 121 students were analyzed using Pearson correlation coefficient, paired t-test, ANOVA, and Scheffe test. Results: Students held negative attitudes toward both types of elders except for generosity dimension toward general elders showing a neutral attitude. Elders with dementia were evaluated more negatively than general elders in all the dimensions of vitality, generosity and flexibility. Vitality and generosity toward general elders were different according to intimacy and the degree of communication with elders. Generosity toward general elders was also different according to students' religious beliefs. Students with interest in elders/issues showed more negative attitudes of vitality and flexibility toward elders with dementia. Conclusions: Students in general had negative attitudes toward elders and more negative attitudes toward elders with dementia. We need to put more efforts into the entire nursing curriculum in order to improve attitudes toward elders with particular concern over attitudes toward elders with dementia.

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Development of Design Formulas for Pipe Loops Used in Ships Considering the Structural Characteristics of Curved Portions (곡선부의 구조 특성을 고려한 선박용 파이프 루프 설계식 개발)

  • Park, Chi-Mo;Bae, Byoung-Il
    • Journal of Ocean Engineering and Technology
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    • v.26 no.5
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    • pp.87-93
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    • 2012
  • Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.

Development of Design Formulas for Pipe Loops Used in Ships Considering the Curvature of Corners (코너부 곡률을 고려한 선박용 파이프 루프 설계식 개발)

  • Park, Chi-Mo;Yang, Park-Dal-Chi
    • Journal of Ocean Engineering and Technology
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    • v.23 no.4
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    • pp.91-99
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    • 2009
  • Many longitudinally arranged pipes in ships are subject to considerable displacement loads caused by the hull girder bending of ships and/or thermal loads in some special pipes through which fluids with highly abnormal temperatures are conveyed. As these loads may cause failure in the pipes or their supporting structures, loops have been widely adopted as a measure to prevent such failure, with the idea that they can lower the stress level in a pipe by absorbing some portion of these loads. But since such loops have some negative effects, such as causing extra manufacturing cost and occupying extra space, the number and dimensions of the loops need to be minimized. This research developed design formulas for pipe loops, modeling them as a spring element, for which the axial stiffness is calculated based on the beam theory, incorporating the effects of the curvature of loop corners and the flexibility of the straight portion of the pipe. The accuracy of the proposed design formulas was verified by comparing two results respectively obtained by the proposed formulas and MSC/NASTRAN. The paper ends with a sample application of the proposed formulas showing their efficiency.