• Title/Summary/Keyword: The Golden Ratio

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Function Optimization Using Quadratically Convergent Algorithms With One Dimensional Search Schemes

  • Kim, Do-Il
    • Journal of Korean Institute of Industrial Engineers
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    • v.14 no.2
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    • pp.25-40
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    • 1988
  • In this paper, a unified method to construct a quadratically convergent algorithm with one dimensional search schemes is described. With this method, a generalized algorithm is derived. As it's particular cases, three quadratically convergent algorithms are performed. They are the rank-one algorithm (Algorithm I), projection algorithm (Algorithm II) and the Fletcher-Reeves algorithm (Algorithm III). As one-dimensional search schemes, the golden-ratio method and dichotomous search are used. Additionally, their computer programming is developed for actual application. The use of this program is provided with the explanation of how to use it, the illustrative examples that are both quadratic and nonquadratic problems and their output. Finally, from the computer output, each algorithm was analyzed from the standpoint of efficiency for performance.

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TMD parameters optimization in different-length suspension bridges using OTLBO algorithm under near and far-field ground motions

  • Alizadeh, Hamed;Lavasani, H.H.
    • Earthquakes and Structures
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    • v.18 no.5
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    • pp.625-635
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    • 2020
  • Suspension bridges have the extended in plan configuration which makes them prone to dynamic events like earthquake. The longer span lead to more flexibility and slender of them. So, control systems seem to be essential in order to protect them against ground motion excitation. Tuned mass damper or in brief TMD is a passive control system that its efficiency is practically proven. Moreover, its parameters i.e. mass ratio, tuning frequency and damping ratio can be optimized in a manner providing the best performance. Meta-heuristic optimization algorithm is a powerful tool to gain this aim. In this study, TMD parameters are optimized in different-length suspension bridges in three distinct cases including 3, 4 and 5 TMDs by observer-teacher-learner based algorithm under a complete set of ground motions formed from both near-field and far-field instances. The Vincent Thomas, Tacoma Narrows and Golden Gate suspension bridges are selected for case studies as short, mean and long span ones, respectively. The results indicate that All cases of used TMDs result in response reduction and case 4TMD can be more suitable for bridges in near and far-field conditions.

Assessment of Optimization Methods for Design of Axial-Flow Fan (축류송풍기 설계를 위한 최적설계기법의 평가)

  • Choi, Jae-Ho;Kim, Kwang-Yong
    • 유체기계공업학회:학술대회논문집
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    • 1999.12a
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    • pp.221-226
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    • 1999
  • Three-dimensional flow analysis and numerical optimization methods are presented for the design of an axial-flow fan. Steady, Incompressible, three-dimensional Reynolds-averaged Wavier-Stokes equations are used as governing equations, and standard k-$\epsilon$ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Steepest descent method, conjugate gradient method and BFGS method are compared to determine the searching directions. Golden section method and quadratic fit-sectioning method are tested for one dimensional search. Objective function is defined as a ratio of generation rate of the turbulent kinetic energy to pressure head. Sweep angle distributions are used as design variables.

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SO2 Injury to Shoots in Five Apple Cultivars (몇가지 사과품종(品種)의 신초(新梢)에 미치는 SO2 가스의 피해(被害))

  • Ku, Ja-Hyeong
    • Korean Journal of Agricultural Science
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    • v.6 no.2
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    • pp.119-124
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    • 1979
  • In order to examine $SO_2$ injury to apple shoots, cutting shoots of five cultivars were exposed to 3 ppm $SO_2$ in vase life conditions. 1. The most sensitive cultivar to $SO_2$ was 'Rall's Genet', and 'Starking' was most tolerant among cultivars tested. 2. Ethylene production of shoots showed peak after 8 hours exposure, when visible injury was not appeared, and was decreased with increase in exposure time. 'Rall's Genet' showed slower decrease in ethylene production than other cultivars. 3. Chlorophyll a, b and a/b ratio were decreased in all cultivars after 40-hr exposures to 3 ppm $SO_2$ and greatly decreased in 'Rall's Genet' compared to other cultivars.

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Natural Dyeing Using Tea Extract II - The Effect of Dyeing Condition on Dyeing Characteristics of Coffee Extract Dyed Silk Farbic-

  • Yoo, Hyun-Geun;Kim, Sin-Hee
    • Journal of Fashion Business
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    • v.10 no.3
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    • pp.78-86
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    • 2006
  • Coffee extract dyeing on silk fabric using various mordanting agents at different mordanting condition was studied in our previous research. Coffee extract dyeing can exert beautiful colors and have several advantages over the conventional natural dyeing. Since most of natural dyes are expensive for mass production, strongly season and source dependent, and hard to store, and therefore, coffee waste was used as natural dye to create beautiful colors in this study. Coffee waste is inexpensive and easy to store, and provide a comparatively regular quality regardless of season and source. The effects of dyeing condition such as dyeing temperature, dyeing time, and liquor ratio on dyeing characteristics of silk fabrics were investigated. Coffee extract dyed silk showed brilliant colors, and the colors were different with the kind of mordant. Cu, Sn, and Al mordanted silks showed golden yellow with subtle change of hue and value, while Fe mordanted silk showed a brownish green color upon coffee extract dyeing. As the dyeing temperature increased, the dyeability generally increased in all mordanted silk fabrics except Fe mordanted silk until $45^{\circ}C$. The dyeing temperature did not affect the dyeability of Fe mordanted silk fabric. As the liquor ratio increased, the dyeability showed a gradual increase in all mordanted silk except Cu mordanted silk. Cu mordanted silk fabric showed an abrupt increase in dyeability at liquor ratio1:150. The dyeing time effect can be separated into 2 stages. During the initial half an hour, the dyeability did not change significantly, and then, increased after 45 min. dyeing time duration. A further increase in dyeing time after 45 min. did not affect the dyeing efficiency in all mordanted silk fabrics except the Cu mordanted.

Effects of Mixed Seeding of Main Revegetation Plants Treated with Different Seeding Amounts of Pennisetum alopecuroides on Cut-Slope Revegetation (수크령 파종량에 따른 주요녹화식물의 혼파가 비탈면 녹화에 미치는 영향)

  • Ham, Kyung-Sik;Shim, Sang-Ryul
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.18 no.1
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    • pp.25-35
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    • 2015
  • Pennisetum aloperculoides is a key revegetation species mixed with other plants species and used for revegetating cut-slopes. The purpose of this research is to identify the effects of mixed seeding of revegetation plants on cut-slope revegetation with respect to the quantity of Pennisetum aloperculoides seeds. The coverage ratio and appearance frequency of Pennisetum aloperculoides, and other revegetation species were measured to assess the cut-slope revegetation. We divided Pennisetum treatments into four groups with different Pennisetum seed quantities of $0g/m^2$, $5g/m^2$, $10g/m^2$, and $15g/m^2$. For each treatment group, we mixed identical quantities of seeds from herbaceous flowers (bird's-boot trefoil, aster, chrysanthemums, golden coreopsis and china pink), cool-season turfgrasses, and woody plants (korean lespedeza, indigo and silk tree). The increase in the quantity of the Pennisetum seeds resulted in the higher coverage ratio for Pennisetum, but in the lower coverage ratio for herbaceous flowers, cool-season turfgrasses, and woody plants. We observed a short-term succession process in which the dominant species shifted in the following order: the initial species Pennisetum, herbaceous flowers, and then lastly woody plants. In case of the appearance frequency, we also observed the higher appearance frequency for Pennisetum and the lower appearance frequency for the other plants due to the increase in the quantity of Pennisetum seeds. Pennisetum, bird's-foot trefoil and china pink showed the tendency to decrease the appearance frequency from one month after seeding while cool-season turfgrasses became extinct due to summer drought. In the woody plants, the appearance frequencies of korean lespedeza and indigo were high due to the decrease in quantity of Pennisetum seeds. The silk trees were damaged from winter frost and none emerged at all in 2013 (the following year after the seeding). Korean lespedeza and indigo appeared to have the short-term rapid dominance over other treated revegetation plants.

A STUDY ON THE RATIO OF THE DENIAL ARCH STRUCTURE IN KOREANS (한국인 치열궁구조의 비례에 관한 연구)

  • Park, Je-Uk;Nahm, Dong-Seok
    • The korean journal of orthodontics
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    • v.18 no.1 s.25
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    • pp.165-173
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    • 1988
  • The purpose of this study was to investigate and evaluate what proportion is the characteristics in Korean dental arches with normal occlusion. Many others have already indicated Golden proportion in normal dental arches, but have not considered any racial and sociocultural differences. So the author postulated $(\sqrt{2})^n$ relations in Koreans. The materials were consisted of 134 dental casts with normal occlusion, which have never undergone orthodontic and prosthodontic procedures. Measurements were made on the arch dimensions using sliding caliper and data were computerized. The findings were as follows: 1. The width between the distal surfaces of the upper centrals, had $(\sqrt{2})^3$ relation with the width between the buccal surfaces of the upper 1 st premolars in Koreans. 2. The width between the distal surfaces of the lower laterals had $(\sqrt{2})$ relation with the width between the distal surfaces of the lower canines, and had $(\sqrt{2})^2$ relation with the distal surfaces of the upper centrals. 3. The width between the distal surfaces of the lower centrals had $(\sqrt{2})^2$ relation with the width between the distal surfaces of the lower laterals, and had $(\sqrt{2})^3$ relation with the width between the distal surfaces of the upper centrals.

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Aesthetic Characteristics of Grecian Style (그리스 스타일의 미적 특성)

  • Ham, Youn-Ja
    • Fashion & Textile Research Journal
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    • v.9 no.6
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    • pp.595-602
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    • 2007
  • This study examined the aesthetic characteristics of Grecian style which is being considered as the representative classic of Western fashion and the transformations of those Grecian styles on the fashion of the twentieth century. This study used positive research method using literatures on art history and clothing history, fashion related publications, and magazines and websites to understand the trend of fashion designer's collections. The study results are as follows. The aesthetic characteristics of Grecian style was considered to be the ideal beauty combined with symmetry, the functional beauty combined with non-construction, and the sensual beauty combined with natural body. The ideal beauty combined with symmetry appears as a style that shows idealistic proportion of a body emphasizing high-waist based on the golden ratio and the body as a whole rather than details. The functional beauty combined with non-construction appears as perfect recreation a body in its original and natural form. The clothing takes a form that does not have any structural design and has simplified cutting and sewing. It uses pins and strings to fix up the form of clothing which is flexible and naturally draped. The sensual beauty combined with natural body is found in natural silhouette dress alluding naked body in connection with Rousseau' naturalism in neoclassic period. Throughout the twentieth century, the desire for Grecian style was conveyed by a single detail or through an array of allusive effects.

A Study on the Sociocultural Backgrounds of the 'Baby Face Fad' and Phrenological Characteristics (동안(童顔) 열풍의 사회문화적 배경과 골상학적 특징)

  • Kim, Nam-Hee;O, In-Young
    • Journal of the Korean Society of Clothing and Textiles
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    • v.33 no.10
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    • pp.1530-1540
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    • 2009
  • Life expectancy has increased and people are more concerned with keeping their 'youth'. Appearance is a competitive edge and people are caught up in a baby face fad that has expanded into a culture and beauty trend. This study examined the definitions and phrenological characteristics of a baby face and the causes of the baby face fad in a review of the baby face as a "sociocultural and beauty cultural code" based on literature, journals, previous papers, and Internet materials. Anatomically speaking, a "baby face" refers to a face that keeps the features of a child's face without aging signs. The baby face fad gained momentum due to the influences of the digital culture, the encouragement of the mass media, changes to the social structure, dietary improvements, new living styles, and an evolving aesthetic sense. The results reveal the sociocultural backgrounds behind the "baby face fad" settling down as a part of culture in addition to the phrenological characteristics of a baby face. It is also estimated that the baby face fad could affect the beauty culture and trends as a social phenomena.

Application of Numerical Optimization Technique to the Design of Fans (송풍기 설계를 위한 수치최적설계기법의 응용)

  • Kim, K.Y.;Choi, J.H.;Kim, T.J.;Rew, H.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.4
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    • pp.566-576
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    • 1995
  • A Computational code has been developed in order to design axial fans by the numerical optimization techniques incorporated with flow analysis code solving three-dimensional Navier-Stokes equation. The steepest descent method and the conjugate gradient method are used to look for the search direction in the design space, and the golden section method is used for one-dimensional search. To solve the constrained optimization problem, sequential unconstrained minimization technique, SUMT, is used with imposed quadratic extended interior penalty functions. In the optimization of two-dimensional cascade design, the ratio of drag coefficient to lift coefficient is minimized by the design variables such as maximum thickness, maximum ordinate of camber and chord wise position of maximum ordinate. In the application of this numerical optimization technique to the design of an axial fan, the efficiency is maximized by the design variables related to the sweep angle distributed by quadratic function along the hub to tip of fan.

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